Understand Microscope

An Introduction to microscope

Tounde Adekounle (born December 20, 1988 in Masséda) is a Togolese footballer, who currently plays for US Masseda

Understand  Microscope 1

Notable equipment of microscope

Camera lenses of R and J Beck are known as Beck Ensign, and the Frena camera was developed in the 1890s, using celluloid films.

A catalogue of work by R & J Beck from 1900 has been digitised as part of the Internet Archive which features the terms of business and pricing from 1900, simplex microscopes, No. 10 London Microscope, No. 22 London Microscope, No. 29 London Microscope, Beck Pathological Microscope, No. 3201 Massive Microscope, Radial Research Microscope, Angular Model Microscope, Beck Combined Binocular and Monocular Microscope, Baby London Microscope, No.3755 Portable Microscope, Pathological Microscope, Binomax magnifier, Greenough Binocular Microscope, Crescent Dissecting Microscope, Cornex Dissecting Microscope, Beck Ultra Violet Microscope made for J. E. Barnard F.R.S., Beck Object Glasses, Eyepieces, Beck-Chapman Opaque Illuminator, Photomigraphic Cameras, Optical Benches, Microtomes, University Micro-projector and Folding Pocket Magnifiers.

Who Invented the Microscope?

A microscope is an instrument used to see tiny things which are otherwise invisible to the naked eye. The word microscope is a combination of two Greek words: mikros "small" and skopos "watcher."

An object will appear larger the closer it is moves to the human eye. But when it is less than 10 inches, it becomes unfocused. However if a simple convex lens is placed between the eye and the object, it can be brought closer than 10 inches and still remain in focus.Ordinary magnifying glasses are basically a simple microscope, and they have been used as such since remote times. So when we speak of the invention of the microscope, we really mean the "compound microscope." But today when we refer to a "microscope" the compound microscope is the kind we mean.The technique of using water-filled glass spheres to produce magnification was known to the Greeks in the 2nd century B.C. In the 10th and 11th centuries A.D. the Arab scientist Alhazen studied the magnification produced by segments of glass spheres.The first compound microscope was devised by a Dutch maker of spectacles, Zacharias Janssen, in 1590. The first person to make extensive use of the microscope used a simple microscope. He was the Dutch scientist Antony van Leeuwenhoek (1632-1723).About 1684 the Dutch physicist Christiaan Huygens invented a modern type of twin-lens eyepiece. Important improvements in the compound microscope were made by the English scientist Robert Hooke (1635-1703). Major improvements in microscope lenses were made by the German physicist Ernst Abbe (1840-1905).The electron microscope was developed by two German scientists, Max Knoll and Ernst Ruska, in 1932. Their work was based on the discovery of electron lenses by another German scientist, Hans Busch.

Leeuwenhoek's lenses, powerful as they were for his time, did not have a great magnification. He used simple magnifiers which he mounted himself. The complicated piece of machinery we call a microscope represents a vast improvement in optical achievements and must be well understood by its users. Many have worked up to the microscope by using hand and pocket lenses to magnify things of interest. This prepares them for the fun of viewing a miniature world through the compound microscope.To study the quill of a porcupine with the aid of a hand lens so that the effective "barb" on its outer end becomes visible, or to view the pollen baskets of the worker bees can be fascinating. But, the real thrill will come when numbers of tiny creatures suddenly become visible through the compound microscope.

Microscope Mechanics

Knowledge of the compound microscope, the name and purpose of each part, is important to the student of microscopy. Starting at the top, you come into contact with the eyepiece, or ocular, which may be on an extension tube of the main tube of the microscope.At the bottom of the tube are the objectives (a very simple microscope may have only one) which are poised above the stage. There are clips to hold the slide in place on the stage, and a hole in the center through which shines light reflected by a mirror attached above the foot of the microscope. The adjustment knob for raising or lowering the tube is on the microscope arm.With the aid of the lenses in the microscope, you are actually bringing the object nearer your eye. Depending upon the power of the lenses, you will see the object in various stages of enlargement.As an example, if the objective magnifies the object 10 diameters- that is, your eye is 10 times nearer to the object - the image it receives is further magnified by the eyepiece which is also 10 times, giving you a magnification of 100 times the object.Care and skill in handling the microscope are essential. The mechanics of the instrument must be mastered first.

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Frequently Asked Questions (FAQ) for Operating Microscope
Frequently Asked Questions (FAQ) for Operating Microscope
1. What is the surgical microscopes market size and share?Surgical/Operating Microscopes market analysis and an industry research report can be accessed at Global Surgical/Operating Microscopes Market - Infinium Global ResearchA complete view of the surgical/operating microscopes industry is provided based on definitions, product classification, applications, major players driving the global surgical/operating microscopes market share and revenue. The information in the form of graphs, pie charts will lead to an easy analysis of an industry. The market share of top leading players, their plans and business policies, growth factors will help other players in gaining useful business tactics. Global Surgical/Operating Microscopes Market by Application 2017 - 2023Plastic and Reconstructive SurgeryOncologyDentistryEnt SurgeryDocumentationGynecology and UrologyNeuro and Spine SurgeryOphthalmologyGlobal Surgical/Operating Microscopes Market by End User 2017 - 2023Outpatient FacilitiesHospitalsMajor Players in the Surgical/Operating Microscopes Market are:Takagi Seiko Co. Ltd.Karl Kaps GmbH & Co. KgArri Medical (Arri Group)Alltion (Wuzhou) Co., Ltd.Accu-Scope Inc.Haag-Streit Surgical GmbH (Mller-Wedel GmbH)Carl Zeiss AGTopcon CorporationDanaher CorporationNovartis AGMajor Regions Play Vital Role in Surgical/Operating Microscopes Market are:North AmericaEuropeAsia-PacificTo Request for Sample Request, visit -Global Surgical/Operating Microscopes Market - Infinium Global Research.------2. Which is better, open ended or closed ended vasectomy? I'm interested in research-based answers, not personal anecdotes.Vasectomy is a simple surgical procedure, which divides the sperm-carrying tubes in the scrotum. It will take 30 to 40 mins. A vasectomy does not work immediately it will take several months to clean the sperm in the vas deferens after the procedure. After Vasectomy the ejaculated semen will contain no sperm but vasectomy will not affect your sexual performance. At Metrocentre, we utilizing the most advanced microsurgical techniques. Metrocentre uses one of the most refined & revered techniques used in the world and we provide the worlds best technique to our patients.Dr. Lekin is one of the best micro-surgeons in the world. Dr. Lekin's personal use of ultrasound for our patients has enabled us to achieve a successful result for difficult cases. We are dedicated to open-ended vasectomy and 3 layers micro-surgical vasectomy reversal and are fully equipped with most advanced operating microscopes, ultrasound & we can perform our technique procedures optimizing the best outcome for the patients. Our doctors also perform vasectomy reversal. Which is better, open ended or closed ended vasectomy? I'm interested in research-based answers, not personal anecdotes------3. What is single-sitting RCT?SINGLE -SITTING ROOT CANAL TREATMENTA Single-sitting Root Canal Treatment is performed in less than an hour using advanced Endodontic technology incorporating latest rotary equipment, apex locators, surgical operating microscope, digital radiography and LASERs.To ensure high degree of clinical success, patients have to be thoroughly examined and appraised of clinical situation by the dentist who can accordingly advise you for a single visit root canal treatment.Is single visit Root Canal Treatment possible in all patients?In clinical conditions with extensive infections single visit Root Canal Treatment is not advised. It is possible in fractured teeth with close pulp (nerve) involvement and teeth with minimal infection.Briefly, in cases of vital pulp, a single-visit root canal treatment can be done whenever possible. This is based on the fact that the pulp is only superficially infected and the root canal is free of bacteria, provided the aseptic chain is maintained during the intra-canal procedures. To understand why Endodontic procedures need to be case specific and dealt with personalized approach, you can refer to the following link is single-sitting RCT?------4. Is hand surgery the hardest surgery?Yes, absolutely. Hand Surgery or the surgery of the hand, wrist and the peripheral nerves of the upper limb is among the most crucial surgeries conducted nowadays. It also encompasses reconstructive surgery that improves upper limb function. The main steps during the surgery are as follows. The surgeon uses fine instruments to handle the delicate structures in the hand and may use magnifying glasses or an operating microscope for repair of the small nerves and arteries in the hand. A typical hand surgery operation is performed as a day-case under a regional anaesthetic , the patient is awake or lightly sedated, according to preference. Post the operation a therapy by a hand specialist is essential for optimal recovery after some types of hand surgery. Among the prominent medical institutes in Bangalore, the Sita Bhateja Speciality Hospital has a dedicated team of eminent surgeons. Under the leadership of Dr. Arvind Bhateja and SBS Hospital uses cutting-edge technology and the very latest surgical techniques. Visit their website to know more: Neurosurgery in Bangalore | Neurosurgeons | Sita Bhateja Specialty HospitalsIs hand surgery the hardest surgery?.------5. Which is the best hospital in India for orthopedics treatment?In my opinion, Vimhans Nayati Multi Super Specialty Hospital could be considered the best hospital in India for orthopedic treatment. Located in New Delhi, the Centre for Advanced Orthopedics and Reconstructive Surgery has been known to successfully perform complex surgeries to treat various kind of injuries including joint replacement, arthritis, knee, hip, shoulder, and sports injuries that too at particularly affordable rates, making it a preferred medical destination for patients in the region.The Centre is specifically termed Advanced as it features state-of-the-art equipment like operating microscope, a computer navigation system, image intensifier, and the latest generation of arthroscopy systems. Furthermore, the hospital is replete with highly experienced and qualified doctors.In addition, Vimhans Nayati requires only a half day admission to perform arthroscopy on patients suffering from Osteoarthritis. The surgery is stitchless and is extremely helpful for patients who experience moderate degree of pain due to degeneration of joints. Within 24 hours, a successful arthroscopy at Vimhans Nayati Multi Super Specialty Hospital can help a patient regain their total knee movement and resume their routine activities without any complications------6. As more & more surgery is done by laser, does that mean the need for surgeons will decline to almost zero?As more & more surgery is done by laser, does that mean the need for surgeons will decline to almost zero?The advent of carbon dioxide laser and other lasers made a revolution in surgery. It was applied in almost all fields of surgery.Benefit in ophthalmology is evident and today lasers are used in eye surgery every day. In ENT surgery, they were tried and at the present moment theyre invaluable in phonosurgery (surgery of the vocal cords). The instrument used is carbon dioxide laser coupled to the operating microscope and suspension laryngoscope. Suspension laryngoscope presents the vocal cords. Microscope enlarges them. Laser coupled to a joystick allows the laser beam to lase the tissues (tumours of the vocal cords or papillomas of the vocal cords).Its essential in removing skin lesions (tattooes mainly). Other types of laser are essential in removing coloured lesions on the skin or elsewhere. And so onStill very useful and expensive instruments but definitely not as popular as they appeared for the very first time------7. What are some instruments used to examine the ear?Many different instruments are used> (including, but not limited to the following)Otic speculum which holds the ear canal open and straightOtoscope, same as above with a light source and magnificationPneumatic Otoscope, as above with the addition of the ability to insufflate air and observe movement of the eardrumTuning Forks which allow for quick and easy gross examination of hearing; need multiple frequencies for completenessOperating Microscope (my favorite) allows greatly magnified 3D visualization of eardrum, ear canal, ossicles and middle ear space. Additionally allows observer to use various other instruments safelyAudiometer: used to more completely measure hearingTympanometer: measures some physical parameters of the ear by bouncing sound waves off of the eardrum and measuring the return with varying air pressures in the ear canal. Will also determine presence of stapedial reflex (search separately)Bithermal caloric testing instruments (different types) Used to measure function of semicircular canalsBrainstem evoked auditory response testing. measures electrical activity of ear in response to sounds.Otoacoustic emission testing: measures sounds created by the inner ear.CAT ScanMRIPolytomography (a type of X-ray)What are some instruments used to examine the ear?.------8. What tips or techniques can be used to hand solder/rework fine pitch parts? closedFor some people soldering under a laboratory stereo microscope - a microscope that has a high stand off distance (so you have room underneath to operate the iron etc.) is sufficient to provide visual feedback and they find they can control their shakes better.These can be relatively expensive but can also be purchased used for $100. Here is an example of one.Lifted from luxeo website.Sometimes the shakes are reduced but supplying resistance that the muscles can work against.Sometimes you can hand solder using solder paste rather than just solder, that reduces the necessity to co-ordinate two hands. And in this case you can use two hands to control the iron in counter opposition. You apply the paste first and then solder.Some people used a slightly weighted tether on the iron, you attach a lanyard and run it up to a pulley with a weight. Again a technique the provides opposition for better muscle control. It can be dampened also.These are techniques that are used to hand probe chips at 100 um or less.------9. I have slight facial paralysis, are there any medical options to add nerves to my face?There are some highly specialised surgical procedures that can be performed from nerve grafts to composite muscle nerve grafts. These surgeries are performed under an operating microscope with a magnification of about 30x. The thread used to sew these nerve ends and arteries together are so fine ('8 to 10-0') that they often cannot be seen to the naked eye. nYou would need to see a neurologist and/or plastic surgeon to direct you to the appropriate surgeon.This answer is not a substitute for professional medical advice. This answer is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor or (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Quora users who provide responses to health-related questions are intended third party beneficiaries with certain rights under Quora's Terms of Service quora. com/about/tos). I have slight facial paralysis, are there any medical options to add nerves to my face?------10. What is the reliability tetsing of a printed circuit board? And what is the procedure??By reliability you might mean two things and I am not sure which. As part of production there are typically quality tests that verify that the empty or stuffed board has all of its components and its connections done correctly. For small runs this could be done by eye or visually with a microscope to make sure that Vias are properly connected and that mounting pads are not of the specified required size. The stuffed boards could be checked with meters and compared to the drawings for component location and value. In a large run pricey fixtures that have probes on each key location would be vacuum clamped onto each board and a computer check for component values and voltages would be done automatically. As far as the overall reliability of a board with a specific design there are heat oven cycling tests, vibration tests, flex tests, component-pull test, under and over voltage tests, high-pot tests, and long term operating tests. There also can be destructive tests in which board details are checked with microscopes, thermal cameras and x-rays. .------11. Is surgery necessary in treating varicocele?If it is causing pain and/or infertility, then treatment is necessary.You have 2 options: microsurgery and embolisation.Both on the whole are equally efficacious. With both, make sure you choose a skilled surgeon with years of expertise.If choosing surgery, it is VITAL that the surgeon uses the following equipment: an operating microscope (NOT loupes), a micro-doppler probe (which helps identify arteries), and electrocautery to prevent accidental damage.As to which treatment to use, it is difficult to answer. Many consider surgery to be the gold standard, as embolisation tends to have a higher recurrence/failure rate, and it can be difficult if you have a bilateral varicocele.Other doctors (such as in the NHS) prefer to avoid surgery as a first line measure because there is a 2% chance of losing the testicle due to accidental arterial damage.What I can say is that if the first treatment fails, you can fall on the other as a plan B. Laparoscopic surgery tends to be reserved for cases whereby both of the above treatments fail
2021 06 25
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Woman Shares Gruesome Pics Showing What Years of Gel Manicures Have Done to Her Nails  and It'll Pro
Woman Shares Gruesome Pics Showing What Years of Gel Manicures Have Done to Her Nails and It'll Pro
NO matter how lovely they look, we all know that gel manicures can wreak havoc on our nail beds.Let's be honest though, even that doesn't stop us booking in for our monthly salon appointments... but now one beauty YouTuber has shared the terrifying effects shellac has had on her nails.Australian gel manicure addict Tina Yong filmed the shocking video as part of her "Tinascope" series.Having previously filmed videos where she examines her skin, eyes, and eyelashes under a microscope, Tina has now shed light on the damaging consequences "5 years" of gel manicures can have on the nail beds.From ordinary fluff and dirt to where the nails are slowly peeling away, Tina explained to her 2.4 million subscribers how her nails always "look scratched and thin" after removing her gel.But this was more than just a case of battered nails...Using a digital microscope to film the disgusting video, Tina identified where her "nails have been lifted and peeled off because of the gel polish"."She then likened the huge build-up of dead skin under her nail to "lots of icebergs" around her cuticles.Unsurprisingly, there was also plenty of dirt and "little hairs" hiding under Tina's fragile nails to the point where she had to acknowledge "oh my god, that's so bad!"But there wasn't just a horrifying build-up of dead skin around Tina's battered nails, the beauty vlogger also noticed that her love of gel manicures have also altered the colour of her nails.Estimating to have worn gel nails religiously for the past five to six years, Tina noticed that her nails had now turned a distinct shade of light yellow after previously "always being off white."Tina's up close and personal video has already been viewed over 200,000 times and one horrified follower has said she will "never put my fingers in my mouth again".One intrigued viewer added that she "can't stop watching" even though the video is "SO GROSS."Warning her followers of the dangers of gel manicures, the online beauty guru said: "Usually, if you use normal polish, your nails won't look this when you remove it. They will still look smooth."And if that hasn't convinced us to swap our shellac habit for ordinary polish, we don't know what will.In even more beauty news, this YouTuber uses Poundland beauty products for 24 hours only... and the foundation is a total disaster.Plus this beauty YouTuber shares the surprising kitchen ingredient she uses to shave her bikini line... and you'll definitely have it in your kitchen cupboards.Washing your hair with CHAMPAGNE is the most bonkers beauty braze on Instagram right now... but is it just throwing money down the drain?
2021 06 25
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Binocular  Microscopes
Binocular Microscopes
Simply put, it is a microscope that uses two eyepieces instead of one. The costs to use this type of microscope are comparable to the one with just one eyepiece. Over the years, the popularity of this microscope has grown and today it currently represents the mass majority of microscopes sold. The technology between binocular microscope and a monocular, one eyepiece, microscope is almost identical. The only difference between the two is the cost of the additional materials such as an extra eyepiece.There are three primary types of binocular microscopes.•Student binocular microscope—this is the cheapest of all three primary binocular microscopes. It is called a student microscope because this is what is normally seen in a classroom or student laboratory. Because it is not that expensive this is why schools and colleges choose this type. It is not necessary to purchase a more expensive microscope because this one can do most of the functions that the student will need to do, The standard cost for this microscope is between one and two thousand dollars with the binocular microscope being at the high end of the price.•Benchmark binocular microscope—this is the next highest one in price range of approximately four thousand dollars for a cheap one. If you are not studying to become a molecular scientist or not an advanced one most of the features of this type of microscope will not be used•Research binocular microscope—this is the most advanced microscope that you can purchase and one most people will see but never use. These are huge microscopes that can weigh approximately one hundred thirty pounds. What makes this binocular microscope weigh so much is the various ocular devices along with the complex series of lenses. In the total weight the electronics included inside the microscope are also counted. When deciding to purchase a binocular microscope you need to consider what you are going to use it for because some are high powered while others are not. You need to look at the price because a basic model would be suitable for a high school student but if you are going to college or in medical studies you many need one that is more advanced. Look to see if it has two or three-dimensional capabilities, how easy it is to adjust the illumination, and the construction of the model you are considering. It should be made to keep out the moisture and air so the delicate parts are not damaged. What features you will need depends on your needs.
2021 06 25
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Zoom into a New World with This Microscope Camera
Zoom into a New World with This Microscope Camera
Using a microscope to see cells, zoom in and see what your hair looks like up close, or examine leaves, bugs and nature's other offerings is one of the most interesting parts of high school science class. It was also one of the most expensive: you probably remember the horrified look on your teacher's face if you ever heard the telltale "crunch" of zooming in too closely and breaking your slide. If your interest in everything great and small never died but you don't want to invest hundreds of dollars in a standard microscope (and risk breaking it and shelling out for expensive replacement parts), the 1000X Zoom 1080p Microscope Camera can take you back to science class for less than $40.This microscope camera is great for science buffs, or for people who want to get a closer look at their jewelry, stamp collections, electronics or other small collectibles. It has a 1000X zoom that brings every detail to life, and its camera feature uses a dynamic image sensor to and super-bright white LED lights for crisp images that you can save. The camera feature means that you can also use the microscope to print out a fascinating image that can add a science-meets-art flair to your home, or you can hand it off as a unique gift.Usually, the Zoom Microscope Camera would cost you $129.99, but right now it's 70% off for a sale price of $38.99.The Salon Marketplace team writes about stuff we think you'll like. Salon has affiliate partnerships, so we may get a share of the revenue from your purchase.//
2021 06 25
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Radial Arrangement of Janus-like Setae Permits Friction Control in Spiders
Radial Arrangement of Janus-like Setae Permits Friction Control in Spiders
Dynamic attachment is the key to move on steep surfaces, with mechanisms being still not well understood. The hunting spider Cupiennius salei (Arachnida, Ctenidae) possesses hairy attachment pads (claw tufts) at its distal legs, consisting of directional branched setae. The morphological investigation revealed that adhesive setae are arranged in a radial manner within the distal tarsus. Friction of claw tufts on smooth glass was measured to reveal the functional effect of seta arrangement within the pad. Measurements revealed frictional anisotropy in both longitudinal and transversal directions. Contact behaviour of adhesive setae was investigated in a reflection interference contrast microscope (RICM). Observations on living spiders showed, that only a small part of the hairy pads is in contact at the same time. Thus the direction of frictional forces is depending on leg placement and rotation. This may aid controlling the attachment to the substrate.Three living individuals of the hunting spider K 1877 (Ctenidae) were obtained from a laboratory stock of the Department of Neurobiology, University of Vienna, Austria. Spiders were kept in cylindrical glasses at the room temperature and 95% relative humidity and fed with house crickets () obtained from the local pet shop.The claw tufts were observed with aid of a stereo microscope (M205 A, Leica Microsystems, Wetzlar, Germany) under lateral and coaxial illumination in spiders resting upside-down on the smooth transparent surface of Plexiglas Petri dishes.Tarsi of the four pairs of walking legs of one body side were ablated with a scalpel in spiders anaesthetized with carbon dioxide. The samples were air dried, mounted on metal stubs and sputter coated with a 15 nm layer of gold-palladium. Samples were viewed in the SEM TM-3000 (Hitachi Ltd., Tokyo, Japan) at 15.0 kV using back-scattered electron (BSE) detector.The setup for force measurements was as previously described by Niederegger and Gorb and is displayed in . Freshly ablated tarsi of different walking legs from spiders anaesthetized with carbon dioxide were shaved at their dorsal side and mounted on a Plexiglas slide with bees wax. Tarsi were positioned in the wax so that the median surface of the setal array of the claw tuft was parallel to the Plexiglas slide. Those samples were attached with double sided adhesive tape to the distal cantilever of a load cell force transducer with 10 g force range (World Precision Instruments Inc., Sarasota, FL, USA). A second force transducer of the same type was attached to a micromanipulator (DC3001R with controller MS314, World Precision Instruments Inc., Sarasota, FL, USA) and placed perpendicularly to the first one. A clean glass cover slip was mounted on the lateral edge of the cantilever. Thus, normal force and friction force could be recorded simultaneously. Force curves were recorded with AcqKnowledge 3.7.0 software (Biopac Systems Ltd, Goleta, CA, USA). A laterally installed stereo microscope was used to monitor the sample movements and the proper contact formation between the claw tuft and smooth substrate.Experiments were performed at an environmental temperature of 20–23°C and a relative humidity of 20–25%. The cover slip was brought into contact with the claw tuft and loaded until normal force reached about 7 mN. Then it was horizontally moved for 3 s with the constant velocity of 200 μm·s in the proximal (simulating leg pushing) and distal (simulating leg pulling) direction, and the friction forces, resisting these movements, was recorded. Proximal and distal sliding experiments were done in a randomized order.Similar force measurements were repeated with the same but air dried samples after two days. Additionally, pro- and retrolateral shearing experiments were performed in the pro- and retrolateral lobes of the claw tuft on an air dried anterior leg tarsus. For this purpose, the leg sample was positioned in the way that the surface of respective lobe was oriented parallelly to the surface of the glass cover slip.Force data were obtained by respective processing of the recorded time-force curves. We have taken into account values recorded after two seconds after shear movement was started, to ensure that the contact between the pad and substrate was formed and friction forces have reached plateau. Friction coefficient μ was calculated as the quotient between friction and normal force. Data were statistically compared with R software package (version 2.13.2, ).Contact behaviour between tuft pad and glass substrate was visualized with an inverted light microscope (Axio Observer.A1, Carl Zeiss Microscopy GmbH, Göttingen, Germany). In the RICM mode, the light source is positioned in a way that light is reflected at the interface of direct (real) contact between the glass slide and the object. Zones of direct contact appear as dark spots on the bright background. Similar visualisation techniques were previously used in studies of attachment of cells and frogs.A cleaned glass cover slip was mounted on the stage and viewed at ×200–630 (oil immersion) magnification. The air dried claw tuft was glued onto a sample holder and positioned with the ventral side onto the cover slip. The stage was then manually moved vertically and laterally and the behaviour of spatulae in contact with glass was recorded with a high speed video camera (Photron Fastcam SA1.1, VKT Video Kommunikation GmbH, Pfullingen, Germany) at 500–1000 frames per second.
2021 06 25
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Formation of Printable Granular and Colloidal Chains Through Capillary Effects and Dielectrophoresis
Formation of Printable Granular and Colloidal Chains Through Capillary Effects and Dielectrophoresis
One-dimensional conductive particle assembly holds promise for a variety of practical applications, in particular for a new generation of electronic devices. However, synthesis of such chains with programmable shapes outside a liquid environment has proven difficult. Here we report a route to simply 'pull' flexible granular and colloidal chains out of a dispersion by combining field-directed assembly and capillary effects. These chains are automatically stabilized by liquid bridges formed between adjacent particles, without the need for continuous energy input or special particle functionalization. They can further be deposited onto any surface and form desired conductive patterns, potentially applicable to the manufacturing of simple electronic circuits. Various aspects of our route, including the role of particle size and the voltages needed, are studied in detail. Looking towards practical applications, we also present the possibility of two-dimensional writing, rapid solidification of chains and methods to scale up chain production.The experimental set-up consisted of a signal generator (SDG1025 Siglent), a high-voltage bipolar amplifier (10HVA24-BP1 HVP), –– motorized translation stage (MTS25-Z8 Thorlabs), a digital microscope (AM7115 Dino-Lite) and a PC for collecting images. The signal electrode for pulling out the particles from a dispersion was made of a thin aluminium wire attached to another motorized translation stage for controlling the pulling rate.Silicone oils (Dow Corning 200 with kinematic viscosity 100 cSt; electric conductivity
2021 06 25
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An Elasto-mechanical Unfeelability Cloak Made of Pentamode Metamaterials
An Elasto-mechanical Unfeelability Cloak Made of Pentamode Metamaterials
Metamaterial-based cloaks make objects different from their surrounding appear just like their surrounding. To date, cloaking has been demonstrated experimentally in many fields of research, including electrodynamics at microwave frequencies, optics, static electric conduction, acoustics, fluid dynamics, thermodynamics and quasi two-dimensional solid mechanics. However, cloaking in the seemingly simple case of three-dimensional solid mechanics is more demanding. Here, inspired by invisible core-shell nanoparticles in optics, we design an approximate elasto-mechanical core-shell 'unfeelability' cloak based on pentamode metamaterials. The resulting three-dimensional polymer microstructures with macroscopic overall volume are fabricated by rapid dip-in direct laser writing optical lithography. We quasi-statically deform cloak and control samples in the linear regime and map the displacement fields by autocorrelation-based analysis of recorded movies. The measured and the calculated displacement fields show very good cloaking performance. This means that one can elastically hide objects along these lines.For the fabrication of the mechanical cloak as well as the reference structures, we used the commercially available DLW system Photonic Professional GT (Nanoscribe GmbH, Germany). In this setup, a liquid photoresist (IP-S resist, Nanoscribe GmbH) was polymerized via multi-photon absorption using a frequency-doubled Erbium fibre laser with a center wavelength of 780 nm and with a pulse duration of about 90 fs. The 3D exposure pattern was addressed by laser scanning using a set of galvo-mirrors and mechanical stages. The samples were prepared by drop-casting the negative-tone photoresist on a glass cover slip (22 × 22 × 0.17 mm). To avoid depth-dependent aberrations, the objective lens ( × 25, numerical aperture=0.8, Carl Zeiss) was directly dipped into the resist. Structural data were created in STL file format using the open-source software Blender and COMSOL Multiphysics. The software package Describe (Nanoscribe GmbH) was used to compile the CAD data into machine code. The scan raster was set to 0.5 μm laterally and 1 μm axially. The structure was laterally split into 8 scan fields of about 500 × 500 μm footprint each that were stitched together. The writing speed was set to 5 cm s. After the DLW of the preprogrammed pattern, the exposed sample was developed for 20 min in mr-Dev 600 and acetone. The process was finished in a supercritical point dryer to avoid capillary forces during drying.The images used for the extraction of the strain field were recorded with a camera (Sony GigE Vision XCG-5005CR) attached to a stereo microscope (Leica Mz 125 and a 0.5 × adapter from Leica mount to C-Mount). To reduce data, the images were then cropped to show only the structure and its close vicinity. For each picture taken, a linear stage induced a different predefined strain into the sample. The strain was successively increased in 50 steps towards the maximum value and afterwards decreased in 50 steps back to the initial value with a strain rate of 2% per minute. The glass substrate with the sample was attached to a goniometer and a micrometre stage to allow for positioning and aligning the sample with respect to the rest of the setup. The stamp was moved with a linear stage to which part of a silicon wafer with well-defined surface was attached.The software used to extract the strain field was based on a freely available package. Here, selected markers with a set size of 15 × 15 image pixels were cross-correlated with the images from the measurement. The initial marker positions were fixed in a square grid with a spacing of 15 pixels in both dimensions spanning the entire size of the sample. This resulted in 67 markers along the horizontal direction and about 35 in the vertical. The tracking algorithm was set to a precision of 1/1,000 pixel. After cross-correlation, the position of each marker was known for each image. By subtracting the current marker positions from those of the reference frame, the displacement vector field was calculated for each image. Small movements of the glass substrate were corrected for. Movies of the reference, the obstacle and the cloak sample are given as . There, the full displacement vectors, multiplied by a factor of 4, are depicted. Additional colour coding of the modulus of the displacement vector helps to identify gradients. Colour coding and scales are identical for the three movies.We used the commercial software package COMSOL Multiphysics to numerically solve the static equations for linear elasticity. This means that neither a nonlinearity of the constituent material nor of the structure was accounted for. The geometry with the design parameters described in the main text was built using the internal kernel of COMSOL Multiphysics. The mesh consisted of about 640,000 tetrahedral elements (in COMSOL nomenclature: maximum element size=0.2 × , minimum element size=0.05 × , maximum element growth rate=16, resolution of curvature=0.7 and resolution of narrow regions=0.4) corresponding to 3–4 × 10 degrees of freedom. We used the direct solver MUMPS with a convergence tolerance of 10. As constituent material, we set an isotropic polymer with Young's modulus=1 GPa , Poisson's ratio =0.4 and mass density =1,200 kg m. Owing to the scalability of the underlying equations, Young's modulus and mass density did not even enter into the final results. The Poisson's ratio was not actually important. To deduce the displacements depicted in , we have tracked the connections with diameter in the middle of the extended fcc unit cell with respect to the direction. Further data processing was done like in the experiment.
2021 06 25
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Best Camera for Backpacking: Three Top Choices for Compact Digital Cameras
Best Camera for Backpacking: Three Top Choices for Compact Digital Cameras
Pentax Optio W90 Digital Camera (5 out of 5)The absolute best camera for backpacking might just be a breakthrough offering from Pentax. For the price ($200 on Amazon.com), the dynamic, waterproof, and extremely durable Pentax Optio W90 is jam packed with features well suited for the backpacker. Beginning with its light weight (5.8 ounces) and compact dimensions (4.2 x 2.3 x 1 inches), this sleek device is small enough to have at the ready in a pocket the whole time you're hiking. Since it powers up in 1.3 seconds and there's only a .3 second shutter lag, you can snap any interesting woodland creature that wanders into focus too. With a 5x digital zoom and 12.1 megapixel capacity, you can convince your friends that the stunningly clear 300 pound grizzly bear was a lot closer than it actually was. What's more, you don't have to worry about rain, sleet, or snow because this camera is waterproof (usually when "W" is in a model name, that's what it means) up to 20 feet. So that means you can take plenty of great underwater shots with it too.It's shockproof so long as it's no longer than four feet and don't worry about the dust, desert scramblers. It's really easy to use if you're new to the digital photography world, taking great pictures no matter what skill level you're at along with high quality HD to boot (complete with an editing feature built into the camera). Incidentally, if you're in the market for one, check out The Backpacker's Top Ratings for Handheld GPS. Back to the Pentax W90; for close ups, it has a digital microscope mode to capture a subject that is only a mere centimeter away from the lens. What they deem an Advanced Pixel Track Shake Reduction translates to the user taking clear and crisp pictures while shivering, shaking, or even on a moving surface (or hanging from a rope, climbers). It will operate at 14 and 104 degrees Fahrenheit and everything in between. Finally, you can get it in yellow so that after you're ready to hit the trail again after a break, it sticks out like a sore thumb during your gear check.Olympus Stylus Tough-8010 (5 out of 5)Designed with adventurous souls in mind, the Stylus Tough-8010 out does the other offerings on the list in terms of its rugged frame that can take a 6.6 ft drop and withstand a 220 lb. crushing blow; so it's the optimum choice for the clumsy and those really hard on gear. You can confidently take pictures at deeper depths (33 feet) also. But the rugged design doesn't diminish the ability of this high resolution 14 megapixel to create stunning and vividly detailed photos. The anti-glare 2.7" LCD gives you a nice and wide viewing angle and the 5x optical zoom (that doesn't protrude) can get you really close to wildlife and you can also shoot HD video with ease. This model retails for around $250 on Amazon.com. It has 29 different shooting modes but the Auto option will identify your target and make all the adjustments for you. Dual Image Stabilization combined with ISO sensitivity and a super-quick shutter speed captures those moving objects. The Li-ion rechargeable battery has a decent life at about 200 pictures. This model's one big drawback is that it's slow starting up, and slower between pictures. But if it's landscapes it's great for the money. The Canon PowerShot D10reviewed in the second article in this series is quicker and the image quality is a little better too.But it's also worthy of noting that although the Stylus 1030SW has been discontinued (or what they annoyingly deem as "archived" on the company website) you can still find this outstanding, smash-proof offering on the Web (Amazon has it listed for $420). This Stylus model topped Backpacker Magazine's best gear list in 2009. If they said it's the best camera for backpacking, then it certainly is a well-regarded item to put on your gear list.Nikon Coolpix P6000 Camera – Great Photos and Geotagging TooContinuing on with our choices for the best camera to take backpacking, we move on to Nikon now. The hardy, feature-laden Coolpix P6000 was designed with the rugged backpacker in mind because first of all, it's designed to withstand a pounding either rattling around in the pack or even dropping it (although they do give a four foot maximum). The internal GPS geotags every picture you take with a digital stamp so you know exactly where it was taken. Then, when you return from a trip, it's a breeze to download all your pictures to Google Earth, the post-a-trip feature on Backpacker.com, or Nikon Picturetown. It's a fantastic way to photo journal every trip you take by integrating the pics with maps. Even when the camera is off, it's little electronic brain updates and locks your GPS position. You might want to take a look at this great review of the Coolpix 7000 too, for comparative purposes.This compact and lightweight (8.5 ounces) digital dynamo has a 13.5 megapixel capacity with a 2.7-inch LCD screen that takes stunning pictures that capture the subtleties and shadowy features of the natural world better than most point and shoot offerings. To zero in on distant wildlife, it has a 4x zoom optical lens that never protrudes from the camera because it's internally stacked. When the sun is too bright, you have the option of using the additional viewfinder to frame your images. From those mountain peaks, treasured by many backpackers, this camera has a mode for panorama stitching mode to recreate that breathtaking view. The only downside is the 11 hour battery life you get with the rechargeable cell battery. The experts at Backpacker Magazine gave this the Editor's Choice Award for 2009 which speaks volumes about its prowess in the field. At the time of this writing, it's on sale for $650 on Amazon.com. But you can find it for a lot cheaper than that with a little searching of your own.So there you have it, three models you can't go wrong with that will all withstand any conditions you might encounter, but they also offer some different features that might appeal to you. So get out there and enjoy the wild reaches of this world to get in tune with your true self. And take lots of pictures to remind yourself of that feeling back in this silly world where having to go to jobs is the best we could come up with in 4000 years.This post is part of the series: Best Compact Digital Point-and-Shoots for Outdoor Enthusiasts
2021 06 25
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Introduction to Microscope Slide
Introduction to Microscope Slide
1. Bibliography of microscope slideRichard Cote, Saul Suster, Lawrence Weiss, Noel Weidner (Editor). Modern Surgical Pathology (2 Volume Set). London: W B Saunders. ISBN0-7216-7253-1.CS1 maint: multiple names: authors list (link) CS1 maint: extra text: authors list (link).mw-parser-output cite.citationfont-style:inherit.mw-parser-output .citation qquotes:"""""""'""'".mw-parser-output .id-lock-free a,.mw-parser-output .citation .cs1-lock-free abackground-image:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png");background-image:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg");background-repeat:no-repeat;background-size:9px;background-position:right .1em center.mw-parser-output .id-lock-limited a,.mw-parser-output .id-lock-registration a,.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration abackground-image:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png");background-image:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg");background-repeat:no-repeat;background-size:9px;background-position:right .1em center.mw-parser-output .id-lock-subscription a,.mw-parser-output .citation .cs1-lock-subscription abackground-image:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png");background-image:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg");background-repeat:no-repeat;background-size:9px;background-position:right .1em center.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcolor:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-ws-icon abackground-image:url("//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png");background-image:linear-gradient(transparent,transparent),url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg");background-repeat:no-repeat;background-size:12px;background-position:right .1em center.mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:inherit;padding:inherit.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-maintdisplay:none;color:#33aa33;margin-left:0.3em.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em.mw-parser-output .citation .mw-selflinkfont-weight:inherit------2. Function of microscope slideBefore HM Government wind-up led by minister James Brokenshire, the FSS was the market leader in the supply of forensic science services to police forces in England and Wales, as well as being a source of training, consultancy and scientific support. The FSS originally set up and maintained the UK National DNA Database, but it is now run by the National Policing Improvement Agency (NPIA).The FSS suffered damage to its reputation following the failure to recover blood stains from a shoe in the murder of Damilola Taylor. Further damage occurred when the FSS failed to use the most up-to-date techniques for extracting DNA samples in cases between 2000 and 2005. This led the Association of Chief Police Officers (ACPO) to advise all police forces in England and Wales to review cases where samples had failed to give a DNA profile.TechnologiesThe FSS's innovative and highly sensitive DNA profiling technique called LCN (low copy number) was used in convicting Antoni Imiela (the M25 rapist) and Ronald Castree (for the murder of Lesley Molseed in 1975), but was questioned during the 2007 trial of a suspect in the Omagh bombing. However, a review by the CPS found that "the CPS has not seen anything to suggest that any current problems exist with LCN. Accordingly we conclude that LCN DNA analysis provided by the FSS should remain available as potentially admissible evidence". In addition, other Police Forces around the world are reviewing cases where LCN DNA profiling resulted in the successful prosecution of suspects. Included in this are several high-profile international cases including the murder of Swedish Foreign Minister Anna Lindh by Mijailo Mijailovic and in Australia, the murder of a backpacker Peter Falconio by Bradley John Murdoch and trial of Bradley Robert Edwards for the Claremont serial killings.In later years the FSS drew on internal expertise and key international experts to become a pioneer in forensic software and technology, notably DNA interpretation, databasing, and electronic forensics.------3. Background of microscope slide24 March commemorates the day in 1882 when Dr Robert Koch astounded the scientific community by announcing to a small group of scientists at the University of Berlin's Institute of Hygiene that he had discovered the cause of tuberculosis, the TB bacillus. According to Koch's colleague, Paul Ehrlich, "At this memorable session, Koch appeared before the public with an announcement which marked a turning-point in the story of a virulent human infectious disease. In clear, simple words Koch explained the aetiology of tuberculosis with convincing force, presenting many of his microscope slides and other pieces of evidence." At the time of Koch's announcement in Berlin, TB was raging through Europe and the Americas, causing the death of one out of every seven people. Koch's discovery opened the way toward diagnosing and curing tuberculosis------4. Botanical illustrator of microscope slideA botanical illustrator is a person who paints, sketches or otherwise illustrates botanical subjects. Typical illustrations are in watercolour, but may also be in oils, ink or pencil, or a combination of these. The image may be life size or not, the scale is often shown, and may show the habit and habitat of the plant, the upper and reverse sides of leaves, and details of flowers, bud, seed and root system.Botanical illustration is sometimes used as a type for attribution of a botanical name to a taxon. The inability of botanists to conserve certain dried specimens, or restrictions on safe transport, have meant illustrations have been nominated as the type for some names. Many minute plants, which may only be viewed under a microscope, are often identified by an illustration to overcome the difficulties in using slide mounted specimens. The standards for this are by international agreement (Art 37.5 of the Vienna Code, 2006)...------5. Specimens of microscope slideThere are two major types of specimens submitted for surgical pathology analysis: biopsies and surgical resections.A biopsy is a small piece of tissue removed primarily for the purposes of surgical pathology analysis, most often in order to render a definitive diagnosis. Types of biopsies include core biopsies, which are obtained through the use of large-bore needles, sometimes under the guidance of radiological techniques such as ultrasound, CT scan, or magnetic resonance imaging. Core biopsies, which preserve tissue architecture, should not be confused with fine-needle aspiration specimens, which are analyzed using cytopathology techniques. Incisional biopsies are obtained through diagnostic surgical procedures that remove part of a suspicious lesion, whereas excisional biopsies remove the entire lesion and are similar to therapeutic surgical resections. Excisional biopsies of skin lesions and gastrointestinal polyps are very common. The pathologist's interpretation of a biopsy is critical to establishing the diagnosis of a benign or malignant tumor, and can differentiate between different types and grades of cancer, as well as determining the activity of specific molecular pathways in the tumor. This information is important for estimating the patient's prognosis and for choosing the best treatment to administer. Biopsies are also used to diagnose diseases other than cancer, including inflammatory, infectious, or idiopathic diseases of the skin and gastrointestinal tract, to name only a few.Surgical resection specimens are obtained by the therapeutic surgical removal of an entire diseased area or organ (and occasionally multiple organs). These procedures are often intended as definitive surgical treatment of a disease in which the diagnosis is already known or strongly suspected. However, pathological analysis of these specimens is critically important in confirming the previous diagnosis, staging the extent of malignant disease, establishing whether or not the entire diseased area was removed (a process called "determination of the surgical margin", often using frozen section), identifying the presence of unsuspected concurrent diseases, and providing information for postoperative treatment, such as adjuvant chemotherapy in the case of cancer.In the determination of surgical margin of a surgical resection, one can use the bread loafing technique, or CCPDMA. A special type of CCPDMA is named after a general surgeon, or the Mohs surgery method.------6. Structure of microscope slideThe FSS had several facilities throughout the country, and provided scene-of-crime and forensic investigation services to police forces in England and Wales, as well as to the Crown Prosecution Service, HM Revenue and Customs, HM Coroners' Service, Ministry of Defence Police, British Transport Police and worldwide forensic services.When an executive agency, its two main headquarters were at 109 Lambeth Road (A3202), London and at Priory House on Gooch Street North in Birmingham.Its headquarters were close to the A452, near to where it crosses the M42. The Police in England and Wales spend 170million on forensic science.LaboratoriesIt had seven main laboratories across England and Wales:Trident Court, nr Solihull / BirminghamPriory House BirminghamHinchingbrooke Park, HuntingdonLondon (Lambeth) after becoming an executive agency as until then it had been the Met Lab.Audby Lane, Wetherby, LeedsUsk Road, ChepstowWashington Hall, ChorleyAldermaston Laboratory, Aldermaston------7. Subspecialties of microscope slideMany pathologists seek fellowship-level training, or otherwise pursue expertise in a focused area of surgical pathology. Subspecialization is particularly prevalent in the academic setting, where pathologists may specialise in an area of diagnostic surgical pathology that is relevant to their research, but is becoming increasingly prevalent in private practice as well. Subspecialization has a number of benefits, such as allowing for increased experience and skill at interpreting challenging cases, as well as development of a closer working relationship between the pathologist and clinicians within a subspecialty area. Commonly recognized subspecialties of surgical pathology include the following:Bone pathologyCardiac pathologyCytopathology (A board-certifiable subspecialty in the U.S.)Dermatopathology (A board-certifiable subspecialty in the U.S.)Endocrine pathologyGastrointestinal pathologyGenitourinary pathologyGynecologic pathologyHematopathology (A board-certifiable subspecialty in the U.S.)Neuropathology (A board-certifiable subspecialty in the U.S. and a recognised specialty in the U.K.)Ophthalmic pathologyPediatric pathology (A board-certifiable subspecialty in the U.S. and a recognised specialty in the U.K.)Pulmonary pathologyRenal pathologySoft tissue pathologyBreast pathology
2021 06 25
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Biomimetic Virus-based Colourimetric Sensors
Biomimetic Virus-based Colourimetric Sensors
Many materials in nature change colours in response to stimuli, making them attractive for use as sensor platform. However, both natural materials and their synthetic analogues lack selectivity towards specific chemicals, and introducing such selectivity remains a challenge. Here we report the self-assembly of genetically engineered viruses (M13 phage) into target-specific, colourimetric biosensors. The sensors are composed of phage-bundle nanostructures and exhibit viewing-angle independent colour, similar to collagen structures in turkey skin. On exposure to various volatile organic chemicals, the structures rapidly swell and undergo distinct colour changes. Furthermore, sensors composed of phage displaying trinitrotoluene (TNT)-binding peptide motifs identified from a phage display selectively distinguish TNT down to 300 p.p.b. over similarly structured chemicals. Our tunable, colourimetric sensors can be useful for the detection of a variety of harmful toxicants and pathogens to protect human health and national security.Our group identified a consensus TNT-binding peptide sequence (WHWQ) using phage display with a commercially available 12mer linear peptide library (Ph.D.-12). To incorporate the TNT-binding peptide, we genetically engineered the M13 phage's major coat proteins (pVIII). The desired peptide sequences were inserted between the first and the sixth amino acids of the amino terminus of wild-type pVIII, replacing residues 2–5 (Ala--Pro to Ala-()-Pro). To incorporate the most stable phage to carry the consensus TNT-binding peptide (WHWQ) identified by phage display, we designed a partial library with sequence of the form ADP using the primer: 5′-ATATATCTGCAGCCCGCAAAAGCG GCCTTTAACTCCC-3′ and the primer 5′-GCTGTCTTTCGCTGC AGAGGGTG-3′ to linearize the vector (=A/C/G/T and =G/T). To incorporate the gene sequences, PCR amplification was performed using Phusion DNA Polymerase, two primers (insertion and linearization) and an M13KE vector with an engineered I site as the template. The obtained product was purified on an agarose gel, eluted by spin column purification, digested with I enzyme and recircularized by an overnight ligation at 16 °C with T4 DNA ligase. The ligated DNA vector was transformed into XL1-Blue electroporation competent bacteria and the amplified plasmid sequence was verified at the University of California, Berkeley, DNA sequencing facility. The pVIII library was screened against TNT and the resulting sequences were tested for stability after large-scale amplification. The library member, ADDWHWQEGDP, was finally chosen to create our TNT–Phage litmus sensors. Alanine-substituted control phage (WAW, AHW and WHA) sequences were synthesized by site-directed mutagenesis of the WHW phage. Using similar genetic engineering approaches, we constructed 4E phage as a control. The constructed phages were amplified using bacterial cultures and purified through standard polyethylene glycol precipitation. The phage solution was further purified by filtration through 0.45 μm pore size membranes. To verify phage stability, DNA sequences were confirmed at each step of the amplification.We created the phage self-assembled colour band patterns using a simple pulling method. The colours of the assembled structures were varied by controlling the pulling speed between 20 and 80 μm min. We constructed a home-built phage deposition apparatus by modifying a syringe pump. We programmed software using C to control the motor speed (between 0.1 μm min and 30 mm min) through an RS232C cable. For preparing Phage litmus matrices, we used 6 mg ml 4E phage suspensions in Tris-buffered saline (12.5 mM Tris and 37.5 mM NaCl, pH 7.5) or 2.4 mg ml WHW-phage suspensions in DI water. A spectrum of coloured bands (each band was obtained at a different pulling speed) was clearly perceptible when the matrices were deposited on gold-coated Si wafers.Fresh turkey head samples were donated from a local turkey farm (Pitman Farms, Sanger, CA, USA). The heads were obtained through overnight delivery immediately after they were slaughtered. The fresh turkey skin samples were immediately taken and processed for optical microscopy and transmission electron microscopy. For histology, 0.5 × 1 cm turkey skin samples were soaked in 20% sucrose in PBS for 2 h, embedded in OCT Compound (Sakura, Torrance, CA, USA), cryosectioned at 5 μm thickness (Shandon Cryostat, Asheville, NC) and stained with Masson's trichrome. Images were collected using an IX71 Microscope (Olympus, Tokyo, Japan). Transmission electron microscopy samples were fixed with 2% glutaraldehyde in 0.1 M sodium cacodylate (pH 7.2) for 1 h, post-fixed with 1% osmium tetroxide in 0.1 M sodium cacodylate (pH 7.2) and rinsed three times with sodium cacodylate (pH 7.2). Dehydration was done using a graded ethanol series (20, 40, 60, 80, 100 and 100%) followed by step-wise infiltration with epon-araldite resin (two parts acetone/one part resin for 1 h, one part acetone/one part resin for 1 h, one part acetone/two parts resin for 1 h, 100% resin for 1 h, 100% resin overnight, 100% resin with benzyl dimethylamine (BDMA) for 1 h) and heat polymerized in a 60 °C oven. Sample blocks were sectioned at 90 nm using a Leica EM UC6 microtome (Leica Microsystems Inc., Buffalo Grove, IL 60089, USA). Grids were stained with 2% uranyl acetate and Reynolds' lead citrate. Imaging was done using a FEI Tecnai 12 transmission electron microscope (FEI, Hillsboro, OR 97124, USA).AFM images were collected using an MFP3D AFM (Asylum Research, Santa Barbara, CA) and analysed using Igor Pro 6.0 (WaveMetrics, Inc., Lake Oswego, OR) and Asylum software package (Asylum Research). All images were taken in tapping mode with a tip spring constant of 2 N m. The probe tips (Ted Pella, Inc., Redding, CA) were made of silicon with a 10-nm radius. The humidity experiments were carried out in a closed liquid cell. We injected a fixed quantity of DI water to control the humidity. FFT analysis of AFM cross-sectional height profiles was used to determine the periodicity of the self-assembled nanofilament structures within the Phage litmus matrices. Numerical computation of the Fourier transform was done with a 2D FFT algorithm in OriginPro 8 (Origin Lab Corp., Northampton, MA) and imageJ v1.44p (National Institutes of Health, USA). We calculated the Fourier power spectra expressed in spatial frequency (μm) from the AFM images.Phage litmus matrices were illuminated by a white light source of a Xenon lamp (X-Cite, Exfo, Mississauga, Canada) and the reflected spectra were obtained using a fibre optic spectrophotometer (USB4000, Ocean Optics, Dunedin, FL) through a Y-shaped bifurcated optical fibre (). An optical fibre fixed on an –– stage was positioned normal to the Phage litmus surface and perpendicular to the scanning direction. Reflectance was measured using a gold-coated Si wafer as a reference. The humidity experiments were performed in a closed glove box (Plas Labs, Inc., Lansing, MI). The humidity was controlled by DI water and monitored using a hygrometer (VWR International Inc., West Chester, PA).To characterize the reflectance spectra of the Phage litmus under omnidirectional illumination, we lit a box coated with aluminium foil with a lamp (Incandescent Light, 150 W, DWC Sylvania, USA; ). We characterized the reflectance spectra while rotating the substrate between 10° and 90° from horizontal. A gold-coated Si wafer was used as a reference.To characterize the swelling behaviour of the Phage litmus, we performed GISAXS experiments before and during exposure to humidity (3 ml of DI water in a closed chamber). The GISAXS data were collected at the beamline 7.3.3 at the Advanced Light Source at Lawrence Berkeley National Laboratory. X-rays with a wavelength of 1.23984 Å (10 keV) were used, and the scattering spectra were collected on an ADSC Quantum 4 μm CCD detector with an active area of 188 × 188 mm (2,304 × 2,304 pixels). The scattering profiles were obtained after a 60-s collection time by integrating the 2D scattering pattern. The sample to detector distance was 1.84791, m and the incidence angle was 0.14°. Line-averaged intensities were reported as versus , where =(4/) × sin(/2), was the wavelength of incident X-rays and was the scattering angle.A home-built sensing and analysis system was developed for real-time chemical sensing. The equipment setup consisted of a gas chamber with an optical opening where a digital microscope (Celestron LLC, Torrance, CA) was attached to monitor the colour of the Phage litmus. The chamber with the Phage litmus inside was positioned on top of a heat block to control the temperature of the chamber. A MATLAB programme (Mathworks Inc., Natick, MA) was run on a PC to control the camera settings, to perform real-time readout and processing of the captured images and to display the real-time RGB data. First, the automatic gain of the digital microscope was turned to manual mode and a fixed gain was retained to prevent unwanted automatic compensation of brightness. The number of regions of interest, usually matching the number of different colour bands on the Phage litmus, was input by keyboard. Next, the specific regions to compare were selected from the first image (reference image) by mouse input. The subsequent images were taken and saved according to a pre-set frame rate (usually every 5 s). The change of the average RGB values with respect to the reference image for each region of interest was calculated and displayed on a graph in real time. We provide typical code from which we performed our experiments in . The vapour-phase experiments were performed by injection of a volume of solvent needed to achieve 300 p.p.m. concentration into a small container inside the chamber through an inlet tube. For explosive exposure experiments, we put excess amounts of each explosive crystal (200 mg) in a sealed chamber (20 ml) and controlled the vapour pressures by temperature. We obtained the concentration of all compounds based on the vapour pressure at each temperature with the assumption of vapour ideality. The vapour pressure of TNT, DNT and MNT was obtained from previously reported values. To collect the data at saturated conditions, we held the Phage litmus in the sealed chamber for 30 min and then obtained corresponding sensing results. To test the specificity of our TNT–Phage litmus sensor towards interfering molecules, experiments were performed in mixed vapours of MNT, DNT and TNT. First, we put the small sealed chambers (1 ml) containing excess amounts of each explosive crystal (200 mg) in a large chamber with the phage litmus. Next, we exposed the chambers to MNT, DNT and TNT vapours sequentially using needles to open each small chamber (). A similar setup was used to perform the same experiments in a background of ethanol vapour (). We performed the control experiments using a 4E–Phage litmus sensor ().Surface plasmon resonance analyses were performed using the Kretschmann optical configuration. A tungsten halogen lamp with a multiwavelength light source was used and a polarizer was positioned on the input path of the light for transverse magnetic fields. The prism coupler and the Phage litmus were mounted on an stage. We made an enclosed cell of 100 μl using polydimethylsiloxane (PDMS) moulds. Flow of solution to the cell was implemented using 1 mm internal diameter tube. We injected 1 ml of solution into the cell at a flow rate of 50 μl min. The outflow from the cell was carried through to a reservoir. The reflected spectrum was measured by a fibre optic spectrometer (USB4000-ultraviolet visible, Ocean Optics) and data acquisition was performed using a homemade LabVIEW programme (LabVIEW 2009, National Instrument, Austin, TX). The surface plasmon resonance spectrum was calculated from linearly polarized light parallel/perpendicular to the incidence plane (TM/TE configuration).iColour analyser is an iOS 5 application software built using the Xcode programming language (Xcode 4.2, Apple Inc., Cupertino, CA) and designed for the iPhone (Apple Inc, compatible with the iPod and iPad). This software has been built to analyse colourimetric changes of the RGB components from a Phage litmus in a systematic manner using a handheld device (). As demonstrated in this paper, the RGB colour components and their changes from the Phage litmus can be linked to specific responses from target molecules. The iColour analyser workflow is constituted of different parts (), as follows:: A channel type (picker) is displayed to choose an analysis mode: single or double channel. Single-channel mode samples from one to five colour matrices of a Phage litmus labelled as S1–S5. The results display one to five different colour matrix RGB components in a bar graph and their values on an 8-bit level. Double-channel mode allows for colour comparison analysis between a reference Phage litmus (before exposure to chemical) and the sample Phage litmus (after exposure to chemical) through comparison between one and five matrices. The RGB values displayed will be the difference between the RGB values of the sample and the reference.: Once the user clicks on the single button of this application, the iPhone takes a picture of the Phage litmus. One can resize and crop the picture of the Phage litmus sample to precisely obtain the target area to analyse.: Once the picture is taken, its central area is cropped and displayed. The picture is converted into a matrix containing the RGB and intensity values of each pixel. The vector data from the iPhone digital camera CCD (Omnivision OV5650, Santa Clara, CA) is processed to get the average of the RGB values from 2,592 × 1,944 pixels over the different areas selected by the user. An analysis table displays the RGB component intensity values and their s.d. An analysis graph will display the RGB values obtained from the sample. The 'average' picture displays a synthesized picture made from either the average RGB values in the case of the single analysis mode, or the difference between the average RGB values of the Phage litmus and its reference in the case of the double comparison mode. After displaying the analysis data and the date and time, a screenshot of the interface is saved in the picture browser of the iPhone and can be transferred easily to any computer through e-mail. In this work, for display purposes, the colour ranges of images are expanded from 5- to 8 bits per colour (RGB colour ranges of 0–31 expanded to 0–255).
2021 06 25
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+86 020 8483 5259
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