The Potential Pathway of L-arginine·L-aspartate for Inhibition of Platelet Function

Aim L-Arginine· L-aspartate, a double salt, has been recently reported toinhibit platelet aggregation and thrombosis, but its action mechanism is not clear yet. This studywas conducted to investigate its effect on FITC-PAC-1, an anti-glycoprotein IIb/IIIa monoclonalantibody binding to activated platelets, and on correlative autacoid levels in plasma or inplatelets in order to explore its potential pathway of inhibiting platelet aggregation andthrombosis. Methods Monoclonal antibody binding to activated platelets was assayed by flowcytometry; NO was assessed by colorimetric method. cAMP, TXB_2 or 6-keto-PGF_(1α) levels wereassessed by radioimmunoassay. Results Gavaged 30 mg·kg^(-1) of L-arginine·L-aspartate increasedboth concentration of NO in plasma and 6-keto-PGF_(1) in incubated supernatant of aortic segment ofrats ex vivo (P < 0.05), but it did not influence cAMP content in platelets and the level of TXB_2or 6-keto-PGF_(1) in plasma of rats, whereas ASA significantly lowered TXB_2 or 6-keto-PGF_(1α) inplasma. Both 100 μmol-L^(-1) of L-arginine ·L-aspartate and ASA inhibited FITC-PAC-1 binding toactivated platelets in vitro. Conclusion The increase in NO and PGI_2 release from endo-thelialcells and consequent inhibition of platelet activation may contribute to the inhibition of plateletaggregation and thrombosis by L-arginine· L-aspartate; whereas arachidonic acid or cAMP metabolicpathway is not closely correlative with the studied effect.

Failure analysis of air fan blades

The failure of all 12 blades of an air fan was investigated by metallurgical and mechanical experiments and an examina-tion of the fracture surface. The experimental results show that the cast aluminium-silicon alloy without any modification had a number of material defects, such as coarse grains, a loose structure, a large number of shrinkage holes, a long and thin bold-pin shaped silicon-phase, poor material strength and serious brittleness. In addition, installed on the spindle without elastic conjunction, blade No.10 vibrated and inevitably.spun off due to the large centrifugal force. Therefore, blade No.10 first cracked at the locking handle, then broke at the root, which caused all the other 11 blades to be broken by the crack of blade No.10.

Horizontal trap-door investigation on face failure zone of shield tunneling in sands

A novel horizontal trap-door test system was devised in this study to analyze the face stability of shield tunnels in sands.The test system can be used to investigate both the longitudinal and cross sections of the face failure simultaneously at one single apparatus and was employed to perform face stability tests on small-scaled tunnel models at single gravity.The lateral support pressures and failure zones were studied with varying sand materials and earth covers.The results demonstrate that the tunnel face moves back,the lateral active earth pressure on the tunnel face decreases rapidly to a residual value,and the lateral pressure distribution can be categorized into three stages during the failure process:1)initial state;2)pressure dissipation stage;and 3)pressure zone diminution stage.Furthermore,face failure firstly develops from a stable condition to the local failure state,and then continues to develop to the global failure state that can be divided into two sub-zones with different failure mechanisms:rotational failure zone(lower zone)and gravitational failure zone(upper zone).Further discussion shows that under the effects of soil arching,the shape of the gravitational failure zone can adopt arch shaped(most frequent)and column shaped(in shallow tunnels).Limit support pressure for face stability usually appears atδ/D=0.2%−0.5%(ratio of face displacement to tunnel diameter).

Dynamic Behavior of a New Hydraulic Steel Gate

A new style of hydraulic steel gate based on the principle of bionics is proposed in this paper. It has a fish-like shape and consists of right arches, invert arches, connection components and a face plate. It would be first applied in the project of Caoe River Sluice, used as both tidal barrage and flood gate. Compared with conventional hydraulic steel gate of beam grids, this new style of hydraulic steel gate can save up to 30%-50% of steel consumption. The dynamic behavior of the new gate under the impact load of tidal bore is investigated. The impact load of tidal bore is considered by a load spectrum obtained by field observation over a long period of time. Then a numerical analysis of the gate under the load spectrum is carried out by finite element method. The fluid-structure interaction is considered in the analysis. And a comparison between the response of the gate under the impact load and the response of the gate under the corresponding static load is conducted and indicates that the gate has a dynamic magnification factor of 1.2.

Nonlinear Modeling of a High Precision Servo Injection Molding Machine Including Novel Molding Approach

A nonlinear mathematical model of the injection molding process for electrohydraulic servo injection molding machine (IMM) is developed.It was found necessary to consider the characteristics of asymmetric cylinder for electrohydraulic servo IMM.The model is based on the dynamics of the machine including servo valve,asymmetric cylinder and screw,and the non-Newtonian flow behavior of polymer melt in injection molding is also considered.The performance of the model was evaluated based on novel approach of molding - injection and compress molding,and the results of simulation and experimental data demonstrate the effectiveness of the model.

Periods and Energy Dissipations of a Novel TLD Rectangular Tank with Angle-adjustable Baffles

A novel tuned liquid damper (TLD) rectangular tank with two angle-adjustable baffles was pre- sented.The numerical analysis was performed using the commercial code FLUENT.The standard kinetic energy and dissipation rate turbulent model was employed,which was solved using volume of fluid (VOF) method able to treat both the free surface motion and the viscous stresses over the rigid walls accurately.The relationship between the natural periods of water and the angles of its baffles was studied by numerical sim- ulating of a case,and the changes of energy dissipations were investigated.The natural periods and dampers of the novel TLD can be changed in a wide range by adjusting the baffles' angle,thus it is more effective in controlling the vibration of structures in a wide frequency range.

Seismic Design Loads of Truss Arch Frames with Ceilings subjected to Vertical and Horizontal Earthquake Motions

Spatial structures such as a gymnasium and an exhibition hall often use ceilings because of enhancing sound effects and reducing heating bills. Although the ceiling members fell down on a large scale due to the seismic motion according to the past great earthquake disaster reports, structural engineers particularly do not carry out the seismic design. The study gives structural engineers the equivalent static loads for the design of the earthquake-proof design of the ceiling system. In particular, it is significant to investigate the dynamic behavior and the applied seismic loads for the complicated vibration of the long span arch building structures with RC columns.

A latent form of essential thrombocythemia presenting as portal cavernoma

Essential thrombocythemia with abdominal thrombotic is frequently associated complications including portal cavernoma as a consequence of chronic portal vein thrombosis. Essential thrombocythemia in a latent form is difficult to identify at onset due to the absence of an overt disease phenotype. In the presented case report, the diagnosis of essential thrombocythemia was initially missed because the typical disease phenotype was masked by bleeding and hypersplenism. The correct diagnosis was only reached when the patient experienced persistent thrombocytosis and pseudohyperkalemia after a shunt operation.

门板

哨兵在野地里被敌人的探子捅了，伤很重，要就地做手术，缺一手术台。医官说：“快，找张门板来!”尔东没多想，颠颠急步跑到村子里。

门板上的夏天

我最喜欢的是夏天。夏天好玩的最多。不说白天去游泳、跟着大人去钓黄鳝、爬高落低的去捉知了，单说夏天的晚上，就足够让人觉得有趣了。

Does the Digital Economy Optimize Tourism Industry Structure?Effects and Mechanisms Based on Quantile Regression and Threshold Modeling

A comprehensive evaluation index system is constructed,and the entropy weight TOPSIS method isused to measure the optimization level of the digital economy and tourism industry structure of 30 provinces inChina from 2012 to 2021.Moreover,models such as quantile regression and panel threshold are used to explorethe influence of the digital economy(DIG)on the optimization of the tourism industry structure(TIS)as well as itstransmission mechanism.The study reveals that DIG significantly promotes TIS,which remains valid after endogeneity and robustness tests;the impact of DIG on TIS exhibited a“U-shape”effect that first decreases and thenincreases,and its highest significance is at the 90%quartile level.Threshold model tests revealed a nonlinearthreshold effect with DIG and tourism total factor productivity(TTFP)as a single threshold and tourism technological progress index(TECH)as a double threshold,and the second threshold has the largest effect of 0.163.Mechanism analysis found that the mediating impact of the DIG on the TIS was mediated by increasing the TTFP,and the TECH accounted for the highest proportion of 12.15%.Regional analysis revealed that the role of DIG onthe TIS is Central>East>West>Northeast,and the empowering effect is more significant in the high digital economylevel area and the high tourism industry structure optimization area.

Development?A Study based on Spatial Effects and Threshold Characteristics

As a pivotal element within the modern service industry,tourism possesses the capacity to reconfigure regional economic dynamics,alter resource flow patterns,and notably influence urban green development.By establishing an evaluation index system for urban green development across 60 prefecture-level cities within the Yellow River Basin from 2006 to 2021,this study employs the spatial Durbin model to delve into the nonlinear relationship between the tourism economy and urban green development.Furthermore,it investigates the heterogeneous impact of the tourism economy on green development across varying levels of urbanization.This study reveals several key findings:(1)Both tourism economy and urban green development exhibit significant spatial clustering,with tourism economy showing“midstream>downstream>upstream”and urban green development showing“downstream>midstream>upstream”.(2)The tourism economy exerts a non-linear positive influence on the green development of cities,characterized by a non-linear inverted“S”shape in its direct impact and a nonlinear“S”shape in its indirect impact.(3)As urbanization rate level escalate,the positive influence of the tourism economy on urban green development follows a non-linear trajectory,initially declining before ascending.Specifically,when the urbanization rate level is below the first threshold value,the tourism economy notably promotes urban green development.However,between the first and second threshold values,this positive impact diminishes,only to rebound beyond the second threshold value.

The Effects of Tourism Industry Agglomeration on Tourism Environmental Carrying Capacity: Evidence from a Panel Threshold Model

By utilizing the panel data of 26 cities in the Yangtze River Delta urban agglomeration of China from 2000 to 2018, this study constructs a panel threshold model to examine the nonlinear relationship between Tourism Environmental Carrying Capacity(TECC) and Tourism Industry Agglomeration(TIA). TECC is evaluated based on the Driver-Pressure-State-Impact-Response(DPSIR) model, and TIA is estimated by the location quotient index.The analysis reveals that TIA and TECC both show growth trends and significant regional differences among the 26cities, but the latter fluctuates at certain stages. Moreover, TIA has a significant double threshold effect on TECC,which shows that the positive impact of TIA is enhanced initially but then weakens afterwards. Theoretically, this study contributes to enriching the current literature on TECC from the perspective of TIA. Practically, it could help local governments effectively arrange agglomerations to promote the sustainable development of the tourism industry in China.

Utility of Doppler ultrasonography for predicting improvement of platelet count after transjugular intrahepatic portosystemic shunt

Objective.Portal pressure gradient(PPG)after transjugular intrahepatic portosystemic shunt(TIPS)<12mmHg has been reported as the only factor predictive of increase in platelet count.As flow velocities measured on Doppler ultrasound are related to pressure gradient based on the Bernoulli equation,we used this parameter to predict increased platelet count after TIPS placement.Methods.A total of 161 consecutive patients who underwent TIPS placement entered this retrospective study.The platelet count was measured before,one week after and one month after TIPS placement.Clinically significant thrombocytopenia was defined as platelet count≤100000.Pre-and post-TIPS PPGs were measured.The velocity of blood flow in the proximal,mid and distal TIPS stent was measured using Doppler ultrasound,and the difference in the highest and lowest measured velocity was entitled flow velocity gradient(FVG),which was considered normal when≤100 cm/s.Results.In 121 patients with pre-TIPS thrombocytopenia,the mean platelet count one week and one month after TIPS placement increased 25.7×10^(3) and 35.0 × 10^(3) in 90 patients with PPG≤12mmHg(P=0.028 and P=0.015),while there was no significant change in platelet count in patients with a PPG>12mmHg(P=0.098 and P=0.075).Platelets increased significantly when FVG≤100 cm/s(n=95)vs FVG>100 cm/s(n=26)one week(37.0×10^(3) vs 11.0×10^(3);P=0.005 vs 0.07)and one month after TIPS placement(17.0×10^(3) vs 5.2×10^(3);P=0.01 vs 0.21).Conclusion.FVG>100 cm/s is not associated with increase in post-TIPS platelet count.On the other hand,findings suggestive of proper TIPS function(FVG≤100 cm/s and PPG≤12mmHg)predict a significant increase in post-TIPS platelet count.