Fluorescence microscopy of cereal grains

1982 ◽  
Vol 60 (4) ◽  
pp. 325-329 ◽  
Author(s):  
R. G. Fulcher ◽  
S. I. Wong

The fluorescence microscope is one of the most sensitive instruments available for morphological and microchemical analysis of cereal grains. Recent innovations in illuminating systems, fluorescence chemistry, and specimen preparation methods have combined to provide dramatic improvements over conventional bright-field microscopy in both specificity and sensitivity. Examples of useful fluorescence methods for microscopic analysis of cereals are included.

2014 ◽  
Vol 20 (4) ◽  
pp. 1208-1217 ◽  
Author(s):  
Jan Buytaert ◽  
Jana Goyens ◽  
Daniel De Greef ◽  
Peter Aerts ◽  
Joris Dirckx

AbstractTwo methods are especially suited for tomographic imaging with histological detail of macroscopic samples that consist of multiple tissue types (bone, muscle, nerve or fat): Light sheet (based) fluorescence microscopy (LSFM) and micro-computed tomography (micro-CT). Micro-CT requires staining with heavy chemical elements (and thus fixation and sometimes dehydration) in order to make soft tissue imageable when measured alongside denser structures. LSMF requires fixation, decalcification, dehydration, clearing and staining with a fluorescent dye. The specimen preparation of both imaging methods is prone to shrinkage, which is often not mentioned, let alone quantified. In this paper the presence and degree of shrinkage are quantitatively identified for the selected preparation methods/stains. LSFM delivers a volume shrinkage of 17% for bone, 56% for muscle and 62% for brain tissue. The three most popular micro-CT stains (phosphotungstic acid, iodine with potassium iodide, and iodine in absolute ethanol) deliver a volume shrinkage ranging from 10 to 56% for muscle and 27–66% for brain, while bone does not shrink in micro-CT preparation.


2007 ◽  
Vol 30 (2) ◽  
pp. 88-98 ◽  
Author(s):  
Vanesa García-Macías ◽  
Paulino de Paz ◽  
Felipe Martinez-Pastor ◽  
Mercedes Álvarez ◽  
Susana Gomes-Alves ◽  
...  

Author(s):  
L. Gandolfi ◽  
J. Reiffel

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.


Author(s):  
Toshihiko Takita ◽  
Tomonori Naguro ◽  
Toshio Kameie ◽  
Akihiro Iino ◽  
Kichizo Yamamoto

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.


Author(s):  
H. M. Kerch ◽  
R. A. Gerhardt

Highly porous ceramics are employed in a variety of engineering applications due to their unique mechanical, optical, and electrical characteristics. In order to achieve proper design and function, information about the pore structure must be obtained. Parameters of importance include pore size, pore volume, and size distribution, as well as pore texture and geometry. A quantitative determination of these features for high porosity materials by a microscopic technique is usually not done because artifacts introduced by either the sample preparation method or the image forming process of the microscope make interpretation difficult.Scanning electron microscopy for both fractured and polished surfaces has been utilized extensively for examining pore structures. However, there is uncertainty in distinguishing between topography and pores for the fractured specimen and sample pullout obscures the true morphology for samples that are polished. In addition, very small pores (nm range) cannot be resolved in the S.E.M. On the other hand, T.E.M. has better resolution but the specimen preparation methods involved such as powder dispersion, ion milling, and chemical etching may incur problems ranging from preferential widening of pores to partial or complete destruction of the pore network.


Author(s):  
Tan-Chen Lee ◽  
Jui-Yen Huang ◽  
Li-Chien Chen ◽  
Ruey-Lian Hwang ◽  
David Su

Abstract Device shrinkage has resulted in thinner barriers and smaller vias. Transmission Electron Microscopy (TEM) has become a common technique for barrier profile analysis because of its high image resolution. TEM sample preparation and image interpretation becomes difficult when the size of the small cylindrical via is close to the TEM sample thickness. Effects of different sample thickness and specimen preparation methods, therefore, have been investigated. An automatic FIB program has been shown to be useful in via sample preparation. Techniques for imaging a TEM specimen will be discussed in the paper. Conventional TEM bright field (BF) image is adequate to examine the barrieronly via; however, other techniques are more suitable for a Cu filled via.


2021 ◽  
Vol 9 (8) ◽  
pp. 848
Author(s):  
Elise E. B. LaDouceur ◽  
Linda A. Kuhnz ◽  
Christina Biggs ◽  
Alicia Bitondo ◽  
Megan Olhasso ◽  
...  

Sea pigs (Scotoplanes spp.) are deep-sea dwelling sea cucumbers of the phylum Echinodermata, class Holothuroidea, and order Elasipodida. Few reports are available on the microscopic anatomy of these deep-sea animals. This study describes the histologic findings of two, wild, male and female Scotoplanes sp. collected from Monterey Bay, California. Microscopic findings were similar to other holothuroids, with a few notable exceptions. Sea pigs were bilaterally symmetrical with six pairs of greatly enlarged tube feet arising from the lateral body wall and oriented ventrally for walking. Neither a rete mirabile nor respiratory tree was identified, and the large tube feet may function in respiration. Dorsal papillae protrude from the bivium and are histologically similar to tube feet with a large, muscular water vascular canal in the center. There were 10 buccal tentacles, the epidermis of which was highly folded. Only a single gonad was present in each animal; both male and female had histologic evidence of active gametogenesis. In the male, a presumed protozoal cyst was identified in the aboral intestinal mucosa, and was histologically similar to previous reports of coccidians. This work provides control histology for future investigations of sea pigs and related animals using bright field microscopy.


2021 ◽  
pp. 175815592098715
Author(s):  
José Carrillo-Ortiz ◽  
Santi Guallar ◽  
Jessica Martínez-Vargas ◽  
Javier Quesada

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.


2017 ◽  
pp. 307-344
Author(s):  
Onkar D. Dhingra ◽  
James B. Sinclair

2021 ◽  
Author(s):  
Antentor Hinton ◽  
Prasanna Katti ◽  
Trace A. Christensen ◽  
Margaret Mungai ◽  
Jianqiang Shao ◽  
...  

Mitochondrial dynamics and morphology (fission, fusion, and the formation of nanotunnels) are very sensitive to the cellular environment and may be adversely affected by oxidative stress, changes in calcium levels, and hypoxia. Investigating the precise relationship between the organelle structure and function requires methods that can adequately preserve the structure while providing accurate, quantitative measurements of mitochondrial morphological attributes. Here, we demonstrate a practical approach for preserving and measuring fine structural changes in two-dimensional electron micrographs, obtained using transmission electron microscopy, highlighting the specific advantages of this technique. Additionally, this study defines a set of quantifiable metrics that can be applied to measure mitochondrial architecture and other organellar structures. Finally, we validated specimen preparation methods that avoid the introduction of morphological artifacts in mitochondrial appearance that do not require whole-animal perfusion.


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