371 research outputs found
Ommatidial heterogeneity in the compound eye of the male small white butterfly, Pieris rapae crucivora
The ommatidia in the ventral two-thirds of the compound eye of male Pieris rapae crucivora are not uniform. Each ommatidium contains nine photoreceptor cells. Four cells (R1-4) form the distal two-thirds of the rhabdom, four cells (R5-8) approximately occupy the proximal one-third of the rhabdom, and the ninth cell (R9) takes up a minor basal part of the rhabdom. The R5-8 photoreceptor cells contain clusters of reddish pigment adjacent to the rhabdom. From the position of the pigment clusters, three types of ommatidia can be identified: the trapezoidal (type I), square (type II), and rectangular type (type III). Microspectrophotometry with an epi-illumination microscope has revealed that the reflectance spectra of type I and type III ommatidia peak at 635 nm and those of type II ommatidia peak at 675 nm. The bandwith of the reflectance spectra is 40-50 nm. Type II ommatidia strongly fluoresce under ultra-violet and violet epi-illumination. The three types of ommatidia are randomly distributed. The ommatidial heterogeneity is presumably crucial for color discrimination
Single Spin Asymmetry in Lepton Angular Distribution of Drell-Yan Processes
We study the single spin asymmetry in the lepton angular distribution of
Drell-Yan processes in the frame work of collinear factorization. The asymmetry
has been studied in the past and different results have been obtained. In our
study we take an approach different than that used in the existing study. We
explicitly calculate the transverse-spin dependent part of the differential
cross-section with suitable parton states. Because the spin is transverse, one
has to take multi-parton states for the purpose. Our result agrees with one of
the existing results. A possible reason for the disagreement with others is
discussed.Comment: Typos corrected. Conclusions unchange
Comparison of the effects of edge functionalized graphene oxide membranes on monovalent cation selectivity
Layer-by-layer graphene oxide (GO) membrane in principle has great potential in separating Li+ from monovalent cations, which is achieved by their functionalized interlayer entrance. The edge effects on different monovalent ions, however, are not fully understood. Therefore, molecular dynamics simulations were utilized in this study to separately elucidate the filtration effects of three typical edge functional groups, which were carboxyl (COOH), hydroxyl (OH), and hydrogen (H), on the LiCl, NaCl, and KCl solutions. The results revealed that the water permeance was dominantly influenced by the steric size of edge functional groups. It could also be affected by the ions blocked at the entrance. The drastic dehydration of the hydrated Na+ and K+ caused by the OH edge required more energy that led to higher ion rejection. The compressed-dehydrated hydration shell, which was tuned by the edge functional groups, introduced repulsion from Na+ and attraction from Li+ on Cl− when they were 3–5 Å away from each other. It would be strategic to use all three edge functional groups to retain NaCl in the retentate stream while allowing selective permeance of LiCl and the OH edge could additionally retain KCl
Relationship between Desalination Performance of Graphene Oxide Membranes and Edge Functional Groups
High desalination efficiency in principle could be achieved by layer-by-layer graphene oxide (GO) membranes, which benefits from their entrance-functionalized channels assembled by edge-functionalized GO nanosheets. The effects of these edge functional groups on desalination, however, are not fully understood yet. To study the isolated influence of three typical edge functional groups, namely, carboxyl (-COOH), hydroxyl (-OH), and hydrogen (-H), molecular dynamics simulation was used in this work. The results revealed that the edge volumetric blockage effect, resulting in ion permeability at G-H > G-OH > G-COOH membranes, was the dominant mechanistic effect inside the GO membranes with 7 Å interlayer channels. The OH edge has the same effect as the H edge in NaCl/water selectivity because of a unique "ion pulling" effect. Moreover, the OH and H edge-functionalized membranes with 7 Å interlayer channels showed preferential Na+ and Cl- rejections, respectively. This kind of preference leads to a cycle of charging and neutralization in the penetrant reservoir throughout the filtration process. The results from this work suggested that it would be strategic to keep the COOH and H edge functional groups, to maintain the size of interlayer channels in order to stimulate the effects of edge functional groups, and to increase the membrane porosity for designing higher desalination efficiency GO membranes
Effects of Edge Functional Groups on Water Transport in Graphene Oxide Membranes
Graphene oxide (GO) membranes assembled by GO nanosheets exhibit high water flux because of the unique water channels formed by their functionalized layer-by-layer structure. Although water transport in the GO membrane is in principle influenced by the functional groups at the edges of GO nanosheets, this is yet to be fully understood. To fill this knowledge gap, molecular dynamics simulation was employed in this work to gain insights into the influences of three typical edge functional groups of GO nanosheets: Carboxyl (COOH), hydroxyl (OH), and hydrogen (H). A well-controlled numerical analysis with complete isolation of the functional groups at the edges was undertaken. The results reveal that the COOH group has a negative impact on water transport because of its relatively large steric geometric structure, which resists water flow. By contrast, the OH group promotes water transport by uniquely "pulling" water molecules across the nanosheet layer because of its relatively stronger interaction with water. The H atom promotes water transport as well, mainly because of its low-resistance steric structure. Moreover, the size of the inter-edge hub has an apparent impact on the influence of these functional groups on water transport. The results suggest that in the design of high water flux GO membranes, it would be strategic to remove COOH edge functional groups while maintaining a mixture of OH and H edge functional groups
Ameliorative Effects of Neurolytic Celiac Plexus Block on Stress and Inflammation in Rats with Partial Hepatectomy
Purpose: To investigate effects of neurolytic celiac plexus block (NCPB) on stress and inflammation in rats with partial hepatectomy (PH).Methods: A model of PH rat was established, and serum C-reactive protein (CRP); corticosterone (GC); adrenocorticotropin (ACTH); noradrenaline (NA); adrenalin (AD); aspartate transaminase (AST); alanine transaminase (ALT); as well as tumor necrosis factor-α (TNF-α); interleukin (IL)-1β and IL-6; high mobility group box1 (HMGB1); and nitric oxide (NO) concentrations in serum assessed after PH. Additionally, Western blotting was performed to determine the effect of NCPB on expressions of glucocorticoid receptors (GR), inhibitor of nuclear factor kappa B (IκB), p65, c-Jun and inducible nitric oxide synthase (iNOS) of PH rats, as well as assay effects of NCPB on nuclear translocation of GR, c- Jun and p65. DNA binding activities of nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1) were also determined.Results: NCPB reduced AST and ALT (P < 0.05), decreased secretion of inflammatory cytokines and NO (P < 0.05), as well as decreased CRP, GC, ACTH, NA and AD after PH (p < 0.05). NCPB increased expressions of GR and IκB, but expressions of p65, c-Jun, and iNOS (p < 0.05). Additionally, NCPB increased nuclear translocation of GR (p < 0.01), but decreased nuclear translocation of p65 and c-Jun after PH (p < 0.05). Additionally, DNA binding activity of NF-κB and AP-1 was decreased by NCPB (p < 0.05).Conclusion: The results indicate that NCPB treatment can significantly inhibit stress and inflammation in PH rats.Keywords: Neurolytic celiac plexus block, Cytokine, Nuclear translocation, Partial hepatectomy, Stress, Inflammatio
Evaluation of SLOG/TCI-III pediatric system on target control infusion of propofol
<p>Abstract</p> <p>Background</p> <p>The target-controlled infusion-III (SLOG/TCI-III) system was derived from a model set up by the local pediatric population for target control infusion of propofol.</p> <p>Methods</p> <p>The current study aimed at evaluating the difference between target concentrations of propofol and performance, which was measured using the SLOG/TCI-III system in children. Thirty children fulfilling the I-II criteria according to American Society of Anesthesiology were enrolled in the study. The target plasma concentration of propofol was fed into the SLOG/TCI-III system and compared with the measured concentrations of propofol. Blood samples were collected and analyzed by high performance liquid chromatography with fluorescence detector. The performance error (PE) was determined for each measured blood propofol concentration. The performances of the TCI-III system were determined by the median performance error (MDPE), the median absolute performance error (MDAPE), and Wobble (the median absolute deviation of each PE from the MDPE), respectively.</p> <p>Results</p> <p>Concentration against target concentration showed good linear correlation: concentration = 1.3428 target concentration - 0.2633 (r = 0.8667). The MDPE and MDAPE of the pediatric system were 10 and 22%, respectively, and the median value for Wobble was 24%. MDPE and MDAPE were less than 15 and 30%, respectively.</p> <p>Conclusions</p> <p>The performance of TCI-III system seems to be in the accepted limits for clinical practice in children.</p
Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay
The decay channel
is studied using a sample of events collected
by the BESIII experiment at BEPCII. A strong enhancement at threshold is
observed in the invariant mass spectrum. The enhancement can be fit
with an -wave Breit-Wigner resonance function with a resulting peak mass of
and a
narrow width that is at the 90% confidence level.
These results are consistent with published BESII results. These mass and width
values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics
Lack of Association of Two Common Polymorphisms rs2910164 and rs11614913 with Susceptibility to Hepatocellular Carcinoma: A Meta-Analysis
BACKGROUND: Single nucleotide polymorphisms (SNPs) in microRNA-coding genes may participate in the process of carcinogenesis by altering the expression of tumor-related microRNAs. It has been suggested that two common SNPs rs2910164 in miR-146a and rs11614913 in miR-196a2 are associated with susceptibility to hepatocellular carcinoma (HCC). However, published results are inconsistent and inconclusive. In the present study, we performed a meta-analysis to systematically summarize the possible association between the two SNPs and the risk for HCC. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a search of case-control studies on the associations of SNPs rs2910164 and/or rs11614913 with susceptibility to HCC in PubMed, EMBASE, ISI Web of Science, Cochrane Central Register of Controlled Trials, ScienceDirect, Wiley Online Library and Chinese National Knowledge Infrastructure databases. Data from eligible studies were extracted for meta-analysis. HCC risk associated with the two polymorphisms was estimated by pooled odds ratios (ORs) and 95% confidence intervals (95% CIs). 5 studies on rs2910164 and 4 studies on rs11614913 were included in our meta-analysis. Our results showed that neither allele frequency nor genotype distribution of the two polymorphisms was associated with risk for HCC in all genetic models. Similarly, subgroup analysis in Chinese population showed no association between the two SNPs and the susceptibility to HCC. CONCLUSIONS/SIGNIFICANCE: This meta-analysis suggests that two common SNPs rs2910164 and rs11614913 are not associated with the risk of HCC. Well-designed studies with larger sample size and more ethnic groups are required to further validate the results
Electroacupuncture pretreatment attenuates cerebral ischemic injury through α7 nicotinic acetylcholine receptor-mediated inhibition of high-mobility group box 1 release in rats
<p>Abstract</p> <p>Background</p> <p>We have previously reported that electroacupuncture (EA) pretreatment induced tolerance against cerebral ischemic injury, but the mechanisms underlying this effect of EA are unknown. In this study, we assessed the effect of EA pretreatment on the expression of α7 nicotinic acetylcholine receptors (α7nAChR), using the ischemia-reperfusion model of focal cerebral ischemia in rats. Further, we investigated the role of high mobility group box 1 (HMGB1) in neuroprotection mediated by the α7nAChR and EA.</p> <p>Methods</p> <p>Rats were treated with EA at the acupoint "Baihui (GV 20)" 24 h before focal cerebral ischemia which was induced for 120 min by middle cerebral artery occlusion. Neurobehavioral scores, infarction volumes, neuronal apoptosis, and HMGB1 levels were evaluated after reperfusion. The α7nAChR agonist PHA-543613 and the antagonist α-bungarotoxin (α-BGT) were used to investigate the role of the α7nAChR in mediating neuroprotective effects. The roles of the α7nAChR and HMGB1 release in neuroprotection were further tested in neuronal cultures exposed to oxygen and glucose deprivation (OGD).</p> <p>Results</p> <p>Our results showed that the expression of α7nAChR was significantly decreased after reperfusion. EA pretreatment prevented the reduction in neuronal expression of α7nAChR after reperfusion in the ischemic penumbra. Pretreatment with PHA-543613 afforded neuroprotective effects against ischemic damage. Moreover, EA pretreatment reduced infarct volume, improved neurological outcome, inhibited neuronal apoptosis and HMGB1 release following reperfusion, and the beneficial effects were attenuated by α-BGT. The HMGB1 levels in plasma and the penumbral brain tissue were correlated with the number of apoptotic neurons in the ischemic penumbra. Furthermore, OGD in cultured neurons triggered HMGB1 release into the culture medium, and this effect was efficiently suppressed by PHA-543,613. Pretreatment with α-BGT reversed the inhibitory effect of PHA-543,613 on HMGB1 release.</p> <p>Conclusion</p> <p>These data demonstrate that EA pretreatment strongly protects the brain against transient cerebral ischemic injury, and inhibits HMGB1 release through α7nAChR activation in rats. These findings suggest the novel potential for stroke interventions harnessing the anti-inflammatory effects of α7nAChR activation, through acupuncture or pharmacological strategies.</p
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