953 research outputs found
Analysis of Stress State of Bolts under Different Anchorage Qualities
A series of pull-out tests were conducted in order to study the stress states of bolts under different anchorage qualities and to simulate the influence of quality defects in empty-slurry and low-strength mortar anchorage in actual engineering. The tests mainly investigated strain characteristics at different positions of the bolts and the effects of strains at the same positions under different anchorage conditions. The research led to the following conclusions: (1) under ultimate bearing capacity, the strain values decayed the fastest along the length of the bolt in the full-length anchorage, the strain values decayed the slowest in the empty-slurry and low-strength mortar anchorage, and the decaying speed of strains in the empty-slurry mortar anchorage was between that of the above two kinds of anchorages; (2) at almost 50% of the ultimate bearing capacity, the strain values were slightly different between the empty-slurry and low-strength mortar anchorage and the empty-slurry anchorage. Obvious differences in strain values occurred when the bolts were continued to be loaded. The strain values of the full-length anchorage bolts were different from those of the other two kinds of anchorages; (3) from the analysis of stress variation characteristics, the safety reserve was the highest for the full-length anchorage under the condition of ultimate bearing capacity, followed by the empty-slurry mortar anchorage, while the safety reserve was the lowest for the empty-slurry and low-strength mortar anchorage. However, in terms of uniformity of force and utilization of the material, the result was reverse
介入治疗下肢动脉硬化闭塞症患者的护理体会
Objective: To explore the nursing methods of lower limb arteriosclerosis occlusion disease with interventional therapy. Methods: Analyze perioperative nursing for 30 cases of lower limb arteriosclerosis occlusion with stenting and balloon dilatation. Results: 27 cases of patients with stent implantation, 3 cases of balloon dilatation, including 3 cases of late stent patients had bypass surgery, the rest has achieved good nursing effect. Conclusion: Perioperative nursing plays an important role in AOS interventional therapy and early recovery of the patient.目的 探讨下肢动脉硬化闭塞症介入治疗的护理方法。方法 对30例下肢动脉硬化闭塞症患者给予了支架植入和球囊扩张术围手术期的护理总结。结果 27例患者行支架植入术,3例球囊扩张术,其中有3例支架植入患者后期做了搭桥手术,其余均取得良好的护理效果。结论 围手术期的护理对于AOS介入治疗起到重要保障,促进了患者的早日康复
Analysis of Stress State of Bolts Under Different Anchorage Qualities
A series of pull-out tests were conducted in order to study the stress states of bolts under different anchorage qualities and to simulate the influence of quality defects in empty-slurry and low-strength mortar anchorage in actual engineering. The tests mainly investigated strain characteristics at different positions of the bolts and the effects of strains at the same positions under different anchorage conditions. The research led to the following conclusions: (1) under ultimate bearing capacity, the strain values decayed the fastest along the length of the bolt in the full-length anchorage, the strain values decayed the slowest in the empty-slurry and low-strength mortar anchorage, and the decaying speed of strains in the empty-slurry mortar anchorage was between that of the above two kinds of anchorages; (2) at almost 50% of the ultimate bearing capacity, the strain values were slightly different between the empty-slurry and low-strength mortar anchorage and the empty-slurry anchorage. Obvious differences in strain values occurred when the bolts were continued to be loaded. The strain values of the full-length anchorage bolts were different from those of the other two kinds of anchorages; (3) from the analysis of stress variation characteristics, the safety reserve was the highest for the full-length anchorage under the condition of ultimate bearing capacity, followed by the empty-slurry mortar anchorage, while the safety reserve was the lowest for the empty-slurry and low-strength mortar anchorage. However, in terms of uniformity of force and utilization of the material, the result was reverse
Insufficient Radiofrequency Ablation Promotes Angiogenesis of Residual Hepatocellular Carcinoma Via HIF-1α/VEGFA
Background: The mechanism of rapid growth of the residual tumor after radiofrequency (RF) ablation is poorly understood. In this study, we investigated the effect of hyperthermia on HepG2 cells and generated a subline with enhanced viability and dys-regulated angiogenesis in vivo, which was used as a model to further determine the molecular mechanism of the rapid growth of residual HCC after RF ablation. Methodology/Principal Findings: Heat treatment was used to establish sublines of HepG2 cells. A subline (HepG2 k) with a relatively higher viability and significant heat tolerance was selected. The cellular protein levels of VEGFA, HIF-1α and p-Akt, VEGFA mRNA and secreted VEGFA were measured, and all of these were up-regulated in this subline compared to parental HepG2 cells. HIF-1α inhibitor YC-1 and VEGFA siRNA inhibited the high viability of the subline. The conditioned media from the subline exerted stronger pro-angiogenic effects. Bevacizumab, VEGFA siRNA and YC-1 inhibited proangiogenic effects of the conditioned media of HepG2 k cells and abolished the difference between parental HepG2 cells and HepG2 k cells. For in vivo studies, a nude mouse model was used, and the efficacy of bavacizumab was determined. HepG2 k tumor had stronger pro-angiogenic effects than parental HepG2 tumor. Bevacizumab could inhibit the tumor growth and angiogenesis, and also eliminate the difference in tumor growth and angiogenesis between parental HepG2 tumor and HepG2 k tumor in vivo. Conclusions/Significance: The angiogenesis induced by HIF1α/VEGFA produced by altered cells after hyperthermia treatment may play an important role in the rapid growth of residual HCC after RF ablation. Bevacizumab may be a good candidate drug for preventing and treating the process
Low temperature of radiofrequency ablation at the target sites can facilitate rapid progression of residual hepatic VX2 carcinoma
<p>Abstract</p> <p>Background</p> <p>Rapid progression of residual tumor after radiofrequency ablation (RFA) of hepatocellular carcinoma has been observed increasingly. However, its underlying mechanisms remain to be clarified. The present study was designed to determine whether low temperature of RFA at the target sites facilitates rapid progression of residual hepatic VX2 carcinoma and to clarify the possible underlying mechanisms.</p> <p>Methods</p> <p>The residual VX2 hepatoma model in rabbits was established by using RFA at 55, 70 and 85°C. Rabbits that were implanted with VX2 hepatoma but did not receive RFA acted as a control group. The relationship between rapid progression of residual hepatic VX2 carcinoma and low temperature of RFA at the target sites was carefully evaluated. A number of potential contributing molecular factors, such as proliferating cell nuclear antigen (PCNA), matrix metalloproteinase 9 (MMP-9), vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and Interleukin-6 (IL-6) were measured.</p> <p>Results</p> <p>The focal tumor volume and lung metastases of RFA-treated rabbits increased significantly compared with the control group (<it>P </it>< 0.05), and the greatest changes were seen in the 55°C group (<it>P </it>< 0.05). Expression of PCNA, MMP-9, VEGF, HGF and IL-6 in tumor tissues increased significantly in the RFA-treated groups compared with the control group, and of the increases were greatest in the 55°C group (<it>P </it>< 0.05). These results were consistent with gross pathological observation. Tumor re-inoculation experiments confirmed that low temperature of RFA at the target sites facilitated rapid progression of residual hepatic VX2 carcinoma.</p> <p>Conclusions</p> <p>Insufficient RFA that is caused by low temperature at the target sites could be an important cause of rapid progression of residual hepatic VX2 carcinoma. Residual hepatic VX2 carcinoma could facilitate its rapid progression through inducing overexpression of several molecular factors, such as PCNA, MMP-9, VEGF, HGF and IL-6.</p
Nuclear liquid-gas phase transition with machine learning
The machine-learning techniques have shown their capability for studying
phase transitions in condensed matter physics. Here, we employ the
machine-learning techniques to study the nuclear liquid-gas phase transition.
We adopt an unsupervised learning and classify the liquid and gas phases of
nuclei directly from the final state raw experimental data of heavy-ion
reactions. Based on a confusion scheme which combines the supervised and
unsupervised learning, we obtain the limiting temperature of the nuclear
liquid-gas phase transition. Its value is consistent with
that obtained by the traditional caloric curve method. Our study explores the
paradigm of combining the machine-learning techniques with heavy-ion
experimental data, and it is also instructive for studying the phase transition
of other uncontrollable systems, like QCD matter.Comment: 9 pages, 8 figures, 1 table; Physical Review Research, in press
(2020
Infant attraction: why social bridging matters for female leadership in Tibetan macaques
Leadership is a key issue in the study of collective behavior in social animals. Affiliation–leadership models predict that dyadic partner preferences based on grooming relationships or alliance formation positively affect an individual’s decision to follow or support a conspecific. In the case of many primate species, females without young infants are attracted to mother–infant dyads. However, the effects of mother–infant–female associations on affiliation–leadership models remain less clear. In free-ranging Tibetan macaques Macaca thibetana, we used social network analysis to examine the importance of “mother-infant-adult female” social bridging events as a predictor of who leads and who follows during group movement. Social bridging is a common behavior in Tibetan macaques and occurs when 2 adults, generally females, engage in coordinated infant handling. Using eigenvector centrality coefficients of social bridging as a measure of social affiliation, we found that among lactating females, initiating bridging behavior with another female played a significant role in leadership success, with the assisting female following the mother during group movement. Among nonlactating females, this was not the case. Our results indicate that infant attraction can be a strong trigger in collective action and directing group movement in Tibetan macaques and provides benefits to mothers who require helpers and social support in order to ensure the safety of their infants. Our study provides new insights into the importance of the third-party effect in rethinking affiliation–leadership models in group-living animals
Prediction feedback in intelligent traffic systems
The optimal information feedback has a significant effect on many
socioeconomic systems like stock market and traffic systems aiming to make full
use of resources. In this paper, we studied dynamics of traffic flow with
real-time information provided and the influence of a feedback strategy named
prediction feedback strategy is introduced, based on a two-route scenario in
which dynamic information can be generated and displayed on the board to guide
road users to make a choice. Our model incorporates the effects of adaptability
into the cellular automaton models of traffic flow and simulation results
adopting this optimal information feedback strategy have demonstrated high
efficiency in controlling spatial distribution of traffic patterns compared
with the other three information feedback strategies, i.e., vehicle number and
flux.Comment: 14 pages, 15 figure
Assessment of structural characteristics of regenerated cellulolytic enzyme lignin based on a mild DMSO/[Emim]OAc dissolution system from triploid of Populus tomentosa Carr.
The structural characteristics of native lignin are essential for the further deconstruction of plant cell walls for value-added application of lignocellulosic biomass.</p
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