241 research outputs found
Sex differences in metabolic rates in field crickets and their dipteran parasitoids
Sex differences in metabolic rate (MR) can result from dimorphism in the performance of energetically demanding activities. Male crickets (Teleogryllus oceanicus) engage in costly calling and aggressive activity not performed by females. Consistent with this difference, we found higher maximal MR, factorial scope, and fat content in males than females. T. oceanicus song is also costly because it attracts the parasitoid fly Ormia ochracea. Parasitized crickets had reduced maximal MR consistent with a metabolic cost to harboring larvae. This cost was greater for females, either because females invest more heavily into reproduction at the expense of metabolic capacity, or because males are under stronger selection to respond to infection. Little is known about O. ochracea outside of its auditory system and parasitic lifestyle. We observed greater resting MR in male flies, possibly reflecting a sex difference in the requirement for metabolic power output, because male flies perform potentially costly mating behavior not seen in females. We found a positive relationship between larval density within a cricket and pupal resting MR, suggesting that crickets in good condition are able to both harbor more larvae and produce larvae with higher resting MR. These results reveal a complex interplay between the metabolism of crickets and their fly parasitoids
Caudal regression syndrome: a rare case report
Caudal regression syndrome is a rare disorder characterised by abnormal development of structures in the caudal region of the embryo like lower lumbar and sacral vertebrae, urogenital and lower gastrointestinal system. It is secondary to abnormal development of mesoderm. Multiple hypotheses like genetic, metabolic and vascular hypoperfusion have been proposed as etiologies. It can be picked up in early second trimester by ultrasound. It has a higher incidence in diabetic pregnancies
Experimental study of tensile response of Strain Hardening UHPFRC at early age
Strain Hardening Ultra High Performance Fibre Reinforced Concrete (SH-UHPFRC), has a high tensile strength (over 10 MPa) and exhibit significant strain hardening (several ‰) under tensile loads. These appealing features make it a suitable material for improving the efficiency and durability of new or existing structures. However, in rehabilitation works, when a layer of a new material is applied on an existing structure, due to restraints from the existing structure, the shrinkage deformations lead to high tensile stresses in the new layer, which can lead to premature cracking. To characterize the effect of the restraining conditions, experimental investigations of evolution of autogenous shrinkage and development of eigenstresses were done using a Temperature Stress Testing Machine (TSTM) at quasi-isothermal curing conditions at 20oC, from the time of casting. Tests were done at partial and full restraint conditions to study the development of the eigenstresses. The tests with 100% restraint are the first of their kind on SH-UHPFRC and the results show that under full restraint conditions, the material enters into the strain-hardening zone of the tensile response
Transition metal saccharide chemistry and biology: syntheses, characterization, solution stability and putative bio-relevant studies of iron-saccharide complexes
A number of Fe(III) complexes of saccharides and their derivatives, and those of ascorbic acid were synthesized, and characterized by a variety of analytical, spectral (FT-IR, UV-Vis, EPR, Mossbauer and EXAFS), magnetic and electrochemical techniques. Results obtained from various methods have shown good correlations. Data obtained from EPR, magnetic susceptibility and EXAFS techniques could be fitted well with the mono-, di- and trinuclear nature of the complexes. The solution stability of these complexes has been established using UV-Vis absorption and cyclic voltammetric techniques as a function of pH of the solution. Mixed valent, Fe(II,III) ascorbate complexes have also been synthesized and characterized. Reductive release of Fe(II) from the complexes using sodium dithionite has been addressed. In vitro absorption of Fe(III)-glucose complex has been studied using everted sacs of rat intestines and the results have been compared with that of simple ferric chloride. Fe(III)-saccharide complexes have shown regular protein synthesis even in hemin-deficient rabbit reticulocyte lysate indicating that these complexes play a role that is equivalent to that played by hemin in order to restore the normal synthesis of protein. These complexes have exhibited enhanced DNA cleavage properties in the presence of hydrogen peroxide with pUC-18 DNA plasmid
Precautionary Regulation in Europe and the United States: A Quantitative Comparison
Much attention has been addressed to the question of whether Europe or the United States adopts a more precautionary stance to the regulation of potential environmental, health, and safety risks. Some commentators suggest that Europe is more risk-averse and precautionary, whereas the US is seen as more risk-taking and optimistic about the prospects for new technology. Others suggest that the US is more precautionary because its regulatory process is more legalistic and adversarial, while Europe is more lax and corporatist in its regulations. The flip-flop hypothesis claims that the US was more precautionary than Europe in the 1970s and early 1980s, and that Europe has become more precautionary since then. We examine the levels and trends in regulation of environmental, health, and safety risks since 1970. Unlike previous research, which has studied only a small set of prominent cases selected non-randomly, we develop a comprehensive list of almost 3,000 risks and code the relative stringency of regulation in Europe and the US for each of 100 risks randomly selected from that list for each year from 1970 through 2004. Our results suggest that: (a) averaging over risks, there is no significant difference in relative precaution over the period, (b) weakly consistent with the flip-flop hypothesis, there is some evidence of a modest shift toward greater relative precaution of European regulation since about 1990, although (c) there is a diversity of trends across risks, of which the most common is no change in relative precaution (including cases where Europe and the US are equally precautionary and where Europe or the US has been consistently more precautionary). The overall finding is of a mixed and diverse pattern of relative transatlantic precaution over the period
Automated analysis of fibrous cap in intravascular optical coherence tomography images of coronary arteries
Thin-cap fibroatheroma (TCFA) and plaque rupture have been recognized as the
most frequent risk factor for thrombosis and acute coronary syndrome.
Intravascular optical coherence tomography (IVOCT) can identify TCFA and assess
cap thickness, which provides an opportunity to assess plaque vulnerability. We
developed an automated method that can detect lipidous plaque and assess
fibrous cap thickness in IVOCT images. This study analyzed a total of 4,360
IVOCT image frames of 77 lesions among 41 patients. To improve segmentation
performance, preprocessing included lumen segmentation, pixel-shifting, and
noise filtering on the raw polar (r, theta) IVOCT images. We used the
DeepLab-v3 plus deep learning model to classify lipidous plaque pixels. After
lipid detection, we automatically detected the outer border of the fibrous cap
using a special dynamic programming algorithm and assessed the cap thickness.
Our method provided excellent discriminability of lipid plaque with a
sensitivity of 85.8% and A-line Dice coefficient of 0.837. By comparing lipid
angle measurements between two analysts following editing of our automated
software, we found good agreement by Bland-Altman analysis (difference 6.7+/-17
degree; mean 196 degree). Our method accurately detected the fibrous cap from
the detected lipid plaque. Automated analysis required a significant
modification for only 5.5% frames. Furthermore, our method showed a good
agreement of fibrous cap thickness between two analysts with Bland-Altman
analysis (4.2+/-14.6 micron; mean 175 micron), indicating little bias between
users and good reproducibility of the measurement. We developed a fully
automated method for fibrous cap quantification in IVOCT images, resulting in
good agreement with determinations by analysts. The method has great potential
to enable highly automated, repeatable, and comprehensive evaluations of TCFAs.Comment: 18 pages, 9 figure
Biological activities of fusarochromanone: a potent anti-cancer agent
Background
Fusarochromanone (FC101) is a small molecule fungal metabolite with a host of interesting biological functions, including very potent anti-angiogenic and direct anti-cancer activity. Results
Herein, we report that FC101 exhibits very potent in-vitro growth inhibitory effects (IC50 ranging from 10nM-2.5 μM) against HaCat (pre-malignant skin), P9-WT (malignant skin), MCF-7 (low malignant breast), MDA-231 (malignant breast), SV-HUC (premalignant bladder), UM-UC14 (malignant bladder), and PC3 (malignant prostate) in a time-course and dose-dependent manner, with the UM-UC14 cells being the most sensitive. FC101 induces apoptosis and an increase in proportion of cells in the sub-G1 phase in both HaCat and P9-WT cell lines as evidenced by cell cycle profile analysis. In a mouse xenograft SCC tumor model, FC101 was well tolerated, non-toxic, and achieved a 30% reduction in tumor size at a dose of 8 mg/kg/day. FC101 is also a potent anti-angiogenenic agent. At nanomolar doses, FC101 inhibits the vascular endothelial growth factor-A (VEGF-A)-mediated proliferation of endothelial cells. Conclusions
Our data presented here indicates that FC101 is an excellent lead candidate for a small molecule anti-cancer agent that simultaneously affects angiogenesis signaling, cancer signal transduction, and apoptosis. Further understanding of the underlying FC101’s molecular mechanism may lead to the design of novel targeted and selective therapeutics, both of which are pursued targets in cancer drug discovery
AltitudeOmics: Red Blood Cell metabolic adaptation to high altitude hypoxia
Red blood cells (RBCs) are key players in systemic oxygen transport. RBCs respond to in vitro hypoxia through the so-called oxygen-dependent metabolic regulation, which involves the competitive binding of deoxyhemoglobin and glycolytic enzymes to the N-terminal cytosolic domain of band 3. This mechanism promotes the accumulation of 2,3-DPG, stabilizing the deoxygenated state of hemoglobin, and cytosol acidification, triggering oxygen off-loading through the Bohr effect. Despite in vitro studies, in vivo adaptations to hypoxia have not yet been completely elucidated. Within the framework of the AltitudeOmics study, erythrocytes were collected from 21 healthy volunteers at sea level, after exposure to high altitude (5260m) for 1, 7 and 16days, and following reascent after 7days at 1525m. UHPLC-MS metabolomics results were correlated to physiological and athletic performance parameters. Immediate metabolic adaptations were noted as early as a few hours from ascending to >5000m, and maintained for 16 days at high altitude. Consistent with the mechanisms elucidated in vitro, hypoxia promoted glycolysis and deregulated the pentose phosphate pathway, as well purine catabolism, glutathione homeostasis, arginine/nitric oxide and sulphur/H2S metabolism. Metabolic adaptations were preserved one week after descent, consistently with improved physical performances in comparison to the first ascendance, suggesting a mechanism of metabolic memory
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