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Advanced Instruments: Characterization of Nanomaterials
Published in M. H. Fulekar, Bhawana Pathak, Environmental Nanotechnology, 2017
TEM is used widely both in material science/metallurgy and biological sciences. In both the cases the specimens must be very thin and able to withstand the high vacuum present inside the instrument. For biological specimens, the maximum specimen thickness is roughly 1 μm to withstand the instrument vacuum. Biological specimens are typically held at liquid nitrogen temperatures after embedding in vitreous ice, or fixated using negative staining material like uranyl acetate or by plastic embedding. The properties on nanocomposites depend, to large extent, on a successful nanolevel dispersion or intercalation/exfoliation of nanoclays. Therefore, monitoring their morphology and dispersion is very crucial. Figure 8.2 shows TEM image of the PP/MMT nanocomposite with the clay content of 4.6 wt.%. The dark line represents an individual clay layer, whereas the bright area represents the PP matrix (Ma et al., 2001). TEM images reveal the distribution and dispersion of nanoparticles in polymer matrices of nanocomposite fibres, nanocoatings, etc. The extent of exfoliation, intercalation and orientation of nanoparticles can also be visualized using the TEM micrograph.
Commercialization of Microfluidic Point-of-Care Diagnostic Devices
Published in Raju Khan, Chetna Dhand, S. K. Sanghi, Shabi Thankaraj Salammal, A. B. P. Mishra, Advanced Microfluidics-Based Point-of-Care Diagnostics, 2022
Pushpesh Ranjan, Mohd. Abubakar Sadique, Arpana Parihar, Chetna Dhand, Alka Mishra, Raju Khan
The further development of microfluidics devices for diagnostic applications is expected to feature in our everyday life. The development of such sensors can be easy by keeping in mind the following points – (i) the applicability of the device, like being home-based or field-based, etc. (ii) type of bio-analyte like serum, plasma, or any other biological specimen, (iii) type of analysis, either molecular or any other, (iv) level of training to personnel for operation, etc. The developed biosensors should be well tested on various validation parameters like specificity, sensitivity, low limit of detection, long-term stability, etc. [23].
Detection — Analytical
Published in Lorris G. Cockerham, Barbara S. Shane, Basic Environmental Toxicology, 2019
Christine A. Purser, Arthur S. Hume
The biological specimen might include human tissue, blood or urine, or animal tissue, that is, wildlife, domestic animals, produce, and meats. The isolation of most organic pollutants from biological tissue, particularly fat, is a formidable task since these chemicals themselves are highly fat soluble. Thus, extraction of these chemicals with solvents can be very difficult and troublesome as the chemical constituents of biological tissue are also soluble in the extracting solvent.
Toward an integrated framework for assessing micropollutants in marine mammals: Challenges, progress, and opportunities
Published in Critical Reviews in Environmental Science and Technology, 2021
Edmond Sanganyado, Ran Bi, Charles Teta, Lucas Buruaem Moreira, Xiaoxuan Yu, Sun Yajing, Tatenda Dalu, Imran Rashid Rajput, Wenhua Liu
Stranded animals and bycatch are widely used in assessing impact of micropollutants in cetaceans. These samples have been a valuable resource for understanding the physiology, diet (stomach content analysis), micropollutant metabolism and distribution (tissue distribution analysis), and micropollutant toxicology (cell culture and pathological analysis) in cetaceans as well as validation of noninvasive and minimally invasive techniques such as skin/biopsy, urine, blow, scat, and earwax sampling. Stranding patterns have been shown to be useful early warning indicators of changes in environmental conditions, species distribution, and health status in marine ecosystems. Hence, the Marine Mammal Protection Act (MMPA) recommended the establishment of a national network that monitor stranding of marine mammals in the US coastal waters (Danil et al., 2010). The inductive inference power of strandings is often questioned since they are of unknown geographic conditions and highly opportunistic. To address this shortcoming, a previous study used photometry to determine drift duration and then reverse drift to determine the geographic origin of stranded dolphins in the French Atlantic coast (Peltier et al., 2012). Condition codes of stranded animals are used to ensure the data is viable for effects assessments (Table 1). Capture-release sampling is common for monitoring seals, sea lions, polar bears, and small cetaceans (Bik et al., 2016; Mancia et al., 2008; Mann, 1999). Capture-release can provide biological specimens such as blood, oral swabs, or skin/blubber samples as well as body status data such as animal size, sex, and age. However, it is a logistical and ethical quandary for endangered species and large mammals such as the blue whale.
Injury risk functions based on population-based finite element model responses: Application to femurs under dynamic three-point bending
Published in Traffic Injury Prevention, 2018
Gwansik Park, Jason Forman, Taewung Kim, Matthew B. Panzer, Jeff R. Crandall
Following the limited number of specimens available, the use of scaling techniques is another challenge that needs to be addressed. The responses and injuries from biomechanical test data usually have a large variation due to the complexity of the human body, including anthropometric differences, local geometric differences, and other physical characteristics of specimens used in tests. Thus, various scaling techniques are sometimes used to normalize subject responses to estimate the response of a target subject size before developing injury risk functions. At present, a mass-based scaling technique is the most commonly used method in the field of injury biomechanics. This scaling technique normalizes human subject responses based on the mass ratio between the subjects assuming a constant density and modulus of elasticity (Eppinger et al. 1984). In addition to the mass-based scaling technique, an impulse momentum-based scaling technique (Mertz 1984) and a structure-based scaling technique (Nie et al. 2016) have been proposed. Although scaling techniques are applied in other engineering fields, there is no consensus on which scaling technique would be valid for normalizing the biomechanical responses in the field of injury biomechanics (Yoganandan et al. 2014). Because scaling techniques represent complex human structure and composition using a limited number of parameters, such as stature or mass, based on the assumption of geometric similarity, they are limited in their ability to capture the effect of variabilities in human body that may affect the responses of a human under car crash conditions. Most of all, the uncertainty in scaling techniques and the limited number of specimens available are challenges intrinsic for the use of biological specimens. Thus, consideration of new approaches to overcome the challenges facing the development of IRFs is necessary.