scholarly journals A revision of bird skin preparation aimed at improving the scientific value of ornithological collections

2021 ◽  
pp. 175815592098715
Author(s):  
José Carrillo-Ortiz ◽  
Santi Guallar ◽  
Jessica Martínez-Vargas ◽  
Javier Quesada
Keyword(s):  
The Body ◽  
Biological Knowledge ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Tarsus Length ◽  
Skin Preparation ◽  
Primary Feather ◽  
Preparation Methods ◽  
Wing Chord ◽  
Scientific Value

The methods used to preserve bird skins in museums have a potentially crucial impact on the feasibility and use of these specimens as a source of biological knowledge, although this subject is rarely broached. Study skins of birds are usually prepared with folded wings and straight legs to facilitate storage in the collection; yet, this method can hamper the measurement and examination of certain important features such as wing-feather moult. To make consultation easier for ornithologists, alternative preparation methods such as the splitting of wings and tarsi from the rest of the animal have been proposed by curators. Our aim was to study whether or not preparing bird specimens with spread limbs makes consultation simpler. First, we used two different methods to prepare two specimens each of two common European passerine species: (1) ‘traditional’ (folded wings and straight tarsi) and (2) ‘spread’ (limbs spread on one side of the body). Then, we asked 22 experienced ornithologists to identify moult limits and take three biometric measurements (wing chord, length of the third primary feather and tarsus length) from all four specimens. Subsequently, we asked which preparation method they preferred for obtaining data. The ‘spread’ preparation was preferred for moult, third primary feather length and tarsus length, whilst the ‘traditional’ preparation was preferred for wing chord. Data obtained from the folded and spread preparations were very highly repeatable within each method but only moderately to highly repeatable between methods. One of the handicaps with the ‘spread’ preparation is the increase in storage space required, a factor that should be taken into account before it is employed. Nevertheless, this specimen preparation technique can greatly facilitate consultation and therefore improve the scientific value of ornithological collections.

Preparation of Large Thin Area Vlsi Tem Specimens by Dimpling With A “Flatting Tool”

1991 ◽  
Vol 254 ◽  
Author(s):  
Helen L. Humiston ◽  
Bryan M. Tracy ◽  
M. Lawrence ◽  
A. Dass
Keyword(s):  
Cross Section ◽  
Milling Time ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Ion Milling ◽  
Sampling Area ◽  
Preparation Methods

AbstractAn alternative VLSI TEM specimen preparation technique has been developed to produce 100μm diameter electron transparent thin area by using a conventional dimpler with a texmet padded ‘flatting tool’ for dimpling and a microcloth padded ‘flatting tool’ for polishing, followed by low angle ion milling. The advantages of this technique are a large sampling area and shorter milling times than conventional specimen preparation methods. In the following, we report the details of the modified dimpling technique. The improvements in available electron transparency, and a decrease in ion milling time are demonstrated with the preparation of planar and cross section VLSI device samples.

scholarly journals A Simple Preparation Method for Full-Range Electron Tomography of Nanoparticles and Fine Powders

2017 ◽  
Vol 23 (6) ◽  
pp. 1150-1158 ◽  
Author(s):  
Elliot Padgett ◽  
Robert Hovden ◽  
Jessica C. DaSilva ◽  
Barnaby D. A. Levin ◽  
John L. Grazul ◽  
...  
Keyword(s):  
Electron Tomography ◽  
Bulk Material ◽  
Automatic Segmentation ◽  
Full Range ◽  
Three Dimensional ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Preparation Methods ◽  
Tomographic Images ◽  
Fine Powders

AbstractElectron tomography has become a valuable and widely used tool for studying the three-dimensional nanostructure of materials and biological specimens. However, the incomplete tilt range provided by conventional sample holders limits the fidelity and quantitative interpretability of tomographic images by leaving a “missing wedge” of unknown information in Fourier space. Imaging over a complete range of angles eliminates missing wedge artifacts and dramatically improves tomogram quality. Full-range tomography is usually accomplished using needle-shaped samples milled from bulk material with focused ion beams, but versatile specimen preparation methods for nanoparticles and other fine powders are lacking. In this work, we present a new preparation technique in which powder specimens are supported on carbon nanofibers that extend beyond the end of a tungsten needle. Using this approach, we produced tomograms of platinum fuel cell catalysts and gold-decorated strontium titanate photocatalyst specimens. Without the missing wedge, these tomograms are free from elongation artifacts, supporting straightforward automatic segmentation and quantitative analysis of key materials properties such as void size and connectivity, and surface area and curvature. This approach may be generalized to other samples that can be dispersed in liquids, such as biological structures, creating new opportunities for high-quality electron tomography across disciplines.

scholarly journals Composting – Recent Investigations for Specimen Preparation

2018 ◽  
Vol 2 ◽  
pp. e26340
Author(s):  
Sheldon Teare ◽  
Katrina McCormick
Keyword(s):  
Marine Mammals ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Subsequent Work ◽  
Preparation Methods ◽  
Preparation Conditions ◽  
Set Up ◽  
The Individual ◽  
Long Term Preservation

Preparators and taxidermists spend a great deal of time preparing osteological materials before these can enter collections. The different preparation methods can have variable results and even the type of specimen being prepared can impact on its overall finish after preparation. This can often result in a lot of extra preparation work to finish or tidy up specimens. Common methods for preparation include maceration, dermestid beetles, burial and composting. Most techniques require initial preparation (flensing) and subsequent work that often introduces more chemicals or handling of the specimens. Each method has uncontrolled elements and difficulties. Dermestids are sometimes temperamental in their preferences and require a lot of care to maintain. Maceration often involves additives like detergents or follow-up chemical treatments. Burial is often highly uncontrolled, leading to problems of drainage and the build-up of unwanted pH environments. Marine mammals or larger specimens present further challenges, being oily or too large to process onsite. When these types of specimens are buried they must often be further processed before entering the collections. All of these different processes can have an impact on the long-term preservation of the individual specimens, which is a concern for conservators. A separate project was set up to investigate how illegally traded bones (tiger in this case) are affected by various environmental (“preparation”) conditions. A series of stations was set up simulating different environments, one being a compost. This started off further investigations into composting as a viable routine preparation technique. We will contrast the recent recovery of three buried beaked whales with composting trials of a frozen unflensed beaked whale skull and a small whole dolphin. The composting techniques seem to allow greater control, and produced excellent results. Our visual results will be complemented with data from the compost site, such as temperature loggers. This is currently an ongoing investigation and it is hoped that further data will be collected over time, such as pH testing of soil samples from burial sites and compost sites. Data from two trials at the Australian Museum – a larger outdoor controlled compost heap and smaller plastic tub composts – will be presented. This project highlights the importance of data collection during specimen preparation. The pathways a specimen goes through before entering a collection have an impact on its long-term preservation and research potential. These data need to be retained.

FIB system for TEM specimen preparation and its application

1996 ◽  
Vol 54 ◽  
pp. 1032-1033
Author(s):  
T. Yaguchi ◽  
T. Kamino ◽  
H. Koike ◽  
T. Ishitani ◽  
Y. Kitano
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Specific Area ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Beam Diameter ◽  
Positional Accuracy ◽  
Preparation Methods ◽  
Specimen Holder ◽  
Transmission Electron

The transmission electron microscope(TEM) is one of the most powerful instrument in materials characterization, and various TEM specimen preparation methods have been developed. It is known that Ar-etching method is most widely applied in the studies of high technology materials. However, it is time-consuming when a specific area is desired for examination. Because it is necessary to iterate through Ar-ion etching and TEM examination until the desired information is obtained.There is a great demand on a new specimen preparation technique that has high positional accuracy, reliability, and throughput.Focused ion beam (FIB) milling has been proposed as a solution to the above requirements. We have developed the FIB system (FB-2000) for SEM/TEM specimen preparation. An external view of the system is shown in Fig.l. The system is designed to use a compatible specimen holder (Fig.2) which allows both FIB milling and TEM observation without re-mounting the specimen. The instrument has maximum accelerating voltage of 30kV and a minimum beam diameter of lOnm. The FIB current density of 15A/cm2 is available.

Enhancement of Contrast in the CEM and STEM Using Bumpy Specimens and Employing the “Dappled Field” Mode of Operation

1974 ◽  
Vol 32 ◽  
pp. 552-553 ◽  
Author(s):  
L. Gandolfi ◽  
J. Reiffel
Keyword(s):  
Operating Mode ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Specimen Preparation ◽  
Field Mode ◽  
Preparation Methods ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Mode Of Operation ◽  
Scanning Transmission

Calculations have been performed on the contrast obtainable, using the Scanning Transmission Electron Microscope, in the observation of thick specimens. Recent research indicates a revival of an earlier interest in the observation of thin specimens with the view of comparing the attainable contrast using both types of specimens.Potential for biological applications of scanning transmission electron microscopy has led to a proliferation of the literature concerning specimen preparation methods and the controversy over “to stain or not to stain” in combination with the use of the dark field operating mode and the same choice of technique using bright field mode of operation has not yet been resolved.

Contrast from epitaxially sandwiched macromolecules

1978 ◽  
Vol 36 (2) ◽  
pp. 226-227
Author(s):  
M. Talianker ◽  
D.G. Brandon
Keyword(s):  
Gold Film ◽  
Lattice Defect ◽  
Gold Foil ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Resolution Limit ◽  
Transmission Electron ◽  
Crystal Lattice Defect ◽  
Void Effect ◽  
Lattice Resolution

A new specimen preparation technique for visualizing macromolecules by conventional transmission electron microscopy has been developed. In this technique the biopolymer-molecule is embedded in a thin monocrystalline gold foil. Such embedding can be performed in the following way: the biopolymer is deposited on an epitaxially-grown thin single-crystal gold film. The molecule is then occluded by further epitaxial growth. In such an epitaxial sandwich an occluded molecule is expected to behave as a crystal-lattice defect and give rise to contrast in the electron microscope.The resolution of the method should be limited only by the precision with which the epitaxially grown gold reflects the details of the molecular structure and, in favorable cases, can approach the lattice resolution limit.In order to estimate the strength of the contrast due to the void-effect arising from occlusion of the DNA-molecule in a gold crystal some calculations were performed.

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

SEM evaluation of the TEM cold-stage double-film specimen

1984 ◽  
Vol 42 ◽  
pp. 272-273
Author(s):  
Jayesh Bellare
Keyword(s):  
Spatial Distribution ◽  
Sample Preparation ◽  
Sample Thickness ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Liquid Sample ◽  
Thin Specimen ◽  
Sample Preparation Technique ◽  
Cold Stage ◽  
Film Specimen

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.

Ultramicrotomy as a Technique for Materials Specimen Preparation

1990 ◽  
Vol 48 (2) ◽  
pp. 428-429
Author(s):  
S.R. Glanvill
Keyword(s):  
Materials Science ◽  
Structural Information ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Cross Sectional ◽  
Surfaces And Interfaces ◽  
Beam Analysis ◽  
Flat Embedding ◽  
20 Nm ◽  
Sectional Analysis

This paper summarizes the application of ultramicrotomy as a specimen preparation technique for some of the Materials Science applications encountered over the past two years. Specimens 20 nm thick by hundreds of μm lateral dimension are readily prepared for electron beam analysis. Materials examined include metals, plastics, ceramics, superconductors, glassy carbons and semiconductors. We have obtain chemical and structural information from these materials using HRTEM, CBED, EDX and EELS analysis. This technique has enabled cross-sectional analysis of surfaces and interfaces of engineering materials and solid state electronic devices, as well as interdiffusion studies across adjacent layers.Samples are embedded in flat embedding moulds with Epon 812 epoxy resin / Methyl Nadic Anhydride mixture, using DY064 accelerator to promote the reaction. The embedded material is vacuum processed to remove trapped air bubbles, thereby improving the strength and sectioning qualities of the cured block. The resin mixture is cured at 60 °C for a period of 80 hr and left to equilibrate at room temperature.

Scanning electron microscopy of human iliac bone by a simple preparation method

1990 ◽  
Vol 48 (3) ◽  
pp. 226-227
Author(s):  
Toshihiko Takita ◽  
Tomonori Naguro ◽  
Toshio Kameie ◽  
Akihiro Iino ◽  
Kichizo Yamamoto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Real Surface ◽  
Public Attention ◽  
Preparation Methods ◽  
The Real ◽  
Simple Preparation ◽  
Scanning Electron

Recently with the increase in advanced age population, the osteoporosis becomes the object of public attention in the field of orthopedics. The surface topography of the bone by scanning electron microscopy (SEM) is one of the most useful means to study the bone metabolism, that is considered to make clear the mechanism of the osteoporosis. Until today many specimen preparation methods for SEM have been reported. They are roughly classified into two; the anorganic preparation and the simple preparation. The former is suitable for observing mineralization, but has the demerit that the real surface of the bone can not be observed and, moreover, the samples prepared by this method are extremely fragile especially in the case of osteoporosis. On the other hand, the latter has the merit that the real information of the bone surface can be obtained, though it is difficult to recognize the functional situation of the bone.

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