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Gilsang Jeong,James Russell,Richard Stouthamer 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.05
The Wolbachia bacterium is known to induce reproductive anomalies in various insect taxa such as cytoplasmic incompatibility, feminization, male killing and parthenogenesis. It is hypothesized that the degree of reproductive anomalies is dependent on the bacterial infection density. In this study, we attempted to test the hypothesis using the tiny egg wasp, Trichogramma kaykai that has served as the model system of parthenogenesis where an unfertilized egg develops into a female due to the bacterial infection. So far this is only found in haplodiploid organisms. The results show that 1) as mothers aged, they started producing male offspring, 2) the sex ratio was negatively correlated with the bacterial infection density, 3) female offspring were more than six times heavily infected with Wolbachia than male offspring in the species. In conclusion, female offspring production, parthenogenesis, is as a function of the Wolbachia bacterial density in this species.
Microfluidic Systems for Assisted Reproductive Technologies: Advantages and Potential Applications
Sequeira Russel C.,Criswell Tracy,Atala Anthony,Yoo James J. 한국조직공학과 재생의학회 2020 조직공학과 재생의학 Vol.17 No.6
Microfluidic technologies have emerged as a powerful tool that can closely replicate the in-vivo physiological conditions of organ systems. Assisted reproductive technology (ART), while being able to achieve successful outcomes, still faces challenges related to technical error, efficiency, cost, and monitoring/assessment. In this review, we provide a brief overview of the uses of microfluidic devices in the culture, maintenance and study of ovarian follicle development for experimental and therapeutic applications. We discuss existing microfluidic platforms for oocyte and sperm selection and maintenance, facilitation of fertilization by in-vitro fertilization/intracytoplastimc sperm injection, and monitoring, selection and maintenance of resulting embryos. Furthermore, we discuss the possibility of future integration of these technologies onto a single platform and the limitations facing the development of these systems. In spite of these challenges, we envision that microfluidic systems will likely evolve and inevitably revolutionize both fundamental, reproductive physiology/toxicology research as well as clinically applicable ART.
Bioinspired Hard–Soft Interface Management for Superior Performance in Carbon Fibre Composites
Ben Newman,James D. Randall,Russell J. Varley,Filip Stojcevski,Luke C. Henderson 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9
Nature has evolved to create materials of unmatched performance governed by the interfacial interactions between hard and soft surfaces. Typically, in a carbon fibre composite, one polymer and one type of carbon fibre is used throughout a laminate. In this work, we use a carbon fibre surface modification approach to vary the fibre–matrix interface throughout the laminate to tailor the soft–hard interfaces. We demonstrate this effect using reclaimed carbon fibre materials in a thermoset polymer, then extend this concept to a thermoplastic polymer matrix–polypropylene. The thermoset specimens examined in this work consist of 5 carbon fibre plies, featuring 0, 1, 3 or 5 surface-modified layers located at the centre of the composite. The largest improvements in physical properties for these composites (yield strength, ultimate flexural strength, and tensile modulus) were found when only 1 modified layer of carbon fibre was placed directly within the centre of the composite. Subsequent investigations revealed that for a polypropylene matrix, where the surface chemistry is tailored specifically for polypropylene, improvements are also observed when mixed surface chemistries are used. This work shows that surface modification of reclaimed carbon fibres as non-woven mats can provide significant improvements in mechanical properties performance for structural composites when used in strategically advantageous locations throughout the composite.
Atrasentan (ABT-627) enhances perfusion and reduces hypoxia in a human tumor xenograft model.
Yang, Kwang Mo,Russell, James,Lupu, Mihaela E,Cho, Hyungjoon,Li, Xiao-Feng,Koutcher, Jason A,Ling, C Clifton Landes Bioscience 2009 Cancer Biology & Therapy Vol.8 No.20
<P>The endothelin-1 antagonist, Atrasentan (ABT-627) was used to modify perfusion in the human tumor xenograft model, HT29, growing in nude mice. Atrasentan produced a significant increase in perfusion, as measured in vivo by Gd-DTPA DCE-MRI. Changes in tumor hypoxia were assessed by comparing the binding of two hypoxia tracers, pimonidazole and EF5 given before and after Atrasentan administration. In vehicle-treated controls, the distribution of EF5 and pimonidazole was very similar. However, Atrasentan treatment was associated with decreased uptake of the second hypoxia tracer (EF5), relative to the first (pimonidazole). Although Atrasentan had no independent effect on the growth of HT29 tumors, Atrasentan combined with 20 Gy radiation led to a modest but significant increase in tumor growth delay compared to radiation alone.</P>
Angel Olivia,Rothwell Glynn,English Russell,Ren James,Cummings Andrew 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.9
The aim of this study is to provide a clear and accessible method to obtain accurate true-stress strain data, and to extend the limited material data beyond the ultimate tensile strength (UTS) for AISI 304L. AISI 304L is used for the outer construction for some types of nuclear transport packages, due to its postyield ductility and high failure strain. Material data for AISI 304L beyond UTS is limited throughout literature. 3D digital image correlation (DIC) was used during a series of uniaxial tensile experiments. Direct method extracted data such as true strain and instantaneous cross-sectional area throughout testing such that the true stress-strain response of the material up to failure could be created. Post processing of the DIC data has a considerable effect on the accuracy of the true stress-strain data produced. Influence of subset size and smoothing of data was investigated by using finite element analysis to inverse model the force displacement response in order to determine the true stress strain curve. The FE force displacement response was iteratively adapted, using subset size and smoothing of the DIC data. Results were validated by matching the force displacement response for the FE model and the experimental force displacement curve
Characterization of PM<sub>2.5</sub>-bound polycyclic aromatic hydrocarbons in Atlanta
Li, Zheng,Sjodin, Andreas,Porter, Erin N.,Patterson Jr., Donald G.,Needham Jr., Larry L.,Lee Jr., Sangil,Russell Jr., Armistead G.,Mulholland Jr., James A. Elsevier 2009 Atmospheric environment Vol.43 No.5
<P><B>Abstract</B></P><P>Twenty-four hour PM<SUB>2.5</SUB> samples from a rural site, an urban site, and a suburban site (next to a major highway) in the metropolitan Atlanta area in December 2003 and June 2004 were analyzed for 19 polycyclic aromatic hydrocarbons (PAH). Extraction of the air samples was conducted using an accelerated solvent extraction method followed by isotope dilution gas chromatography/mass spectrometry determination. Distinct seasonal variations were observed in total PAH concentration (i.e. significantly higher concentrations in December than in June). Mean concentrations for total particulate PAHs in December were 3.16, 4.13, and 3.40ngm<SUP>−3</SUP> for the urban, suburban and rural sites, respectively, compared with 0.60, 0.74, and 0.24ngm<SUP>−3</SUP> in June. Overall, the suburban site, which is impacted by a nearby major highway, had higher PAH concentration than did the urban site. Total PAH concentrations were found to be well correlated with PM<SUB>2.5</SUB>, organic carbon (OC), and elemental carbon (EC) in both months (<I>r</I><SUP>2</SUP>=0.36–0.78, <I>p</I><0.05), although the slopes from the two months were different. PAHs represented on average 0.006% of total PM<SUB>2.5</SUB> mass and 0.017% of OC in June, compared with 0.033% of total PM<SUB>2.5</SUB> and 0.14% of OC in December. Total PAH concentrations were also correlated with potassium ion (<I>r</I><SUP>2</SUP>=0.39, <I>p</I>=0.014) in December, but not in June, suggesting that in winter biomass burning can potentially be an important source for particulate PAH. Retene was found at a higher median air concentration at the rural site than at the urban and suburban sites—unlike the rest of the PAHs, which were found at lower levels at the rural site. Retene also had a larger seasonal difference and had the weakest correlation with the rest of the PAHs measured, suggesting that retene, in particular, might be associated with biomass burning.</P>