Structure-activity Relationships of Vasorelaxing Effect of Polyarginine Oligopeptides

Based on the EDRF(endothelium derived relaxing factor)-like effects for polyarginine Arg-Arg-oH was selected as the lead compound and its derivatives Arg-Arg- OCH_3.Arg Arg-Arg-OH,HO-ArgCOCH_2CH_2COArg-OH,HO-ArgCOCH_2COArg-OH,were synthesized.These substances showed on bioassay various degrees of vasorelaxant activities. With protection for the C-terminal of Arg-Arg-OH with a methyl ester.the vasorelaxing ac- tivitv was decreased.In contrast.when the N-terminal of Arg-OH was protected with mal- onic acid or butane diacid.the biological activites were lower than those of Arg-Arg-OH due to the lowered metabolic rate.With protection of N-terminal of Arg-Arg-OH with L-Arg residue.Arg-Arg-Arg-OH was obtained,which showed a vasorelaxing activity better than that of Arg-Arg-OH.The bioactivities observed on the Wister's rats for the former com- pound become the experimental basis for prodrug design of EDRF.

Human umbilical cord blood-derived stem cells and brain-derived neurotrophic factor protect injured optic nerve:viscoelasticity characterization

The optic nerve is a viscoelastic solid-like biomaterial.Its normal stress relaxation and creep properties enable the nerve to resist constant strain and protect it from injury.We hypothesized that stress relaxation and creep properties of the optic nerve change after injury.Moreover,human brain-derived neurotrophic factor or umbilical cord blood-derived stem cells may restore these changes to normal.To validate this hypothesis,a rabbit model of optic nerve injury was established using a clamp approach.At 7 days after injury,the vitreous body received a one-time injection of 50 μg human brain-derived neurotrophic factor or 1 × 106 human umbilical cord blood-derived stem cells.At 30 days after injury,stress relaxation and creep properties of the optic nerve that received treatment had recovered greatly,with pathological changes in the injured optic nerve also noticeably improved.These results suggest that human brain-derived neurotrophic factor or umbilical cord blood-derived stem cell intervention promotes viscoelasticity recovery of injured optic nerves,and thereby contributes to nerve recovery.

Effect of ocean environmental factors on sound absorption by boric acid relaxation in sea water

By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatures, the effects of pressure, temperature, pH and salinity on (αλ)r and ∫r of the boric acid relaxation in sea water have been estimated. Results show that ( αλ), not only increases with pH but also increases approximately linearly with pressure and temperature, and is nearly proportional to the 1. 35 power of salinity. However, pressure, pH and salinity have negligible effect on ∫r; therefore, ∫r, can be approximately expressed as a function of temperature only. Comparisons of the predicted with the measured ( αλ)r and ∫r in different ocean areas are given.

IMPROVEMENT OF FLUORIMETRIC AND UV－VISIBLE SPECTROPHOTOMETRIC ASSAY METHODS FOR MEASURING NITRIC OXIDE AND／OR EDRF IN BLOOD

The increasing importance of endothelium-derived relaxing factor(EDRF),which has now been identified as nitric oxide (NO),has been underscored by the eltlcidation of its role'in a growing number of normal and pathophysiological processes. Therefore techniques for detection of nitric oxide should serve as useful tools in defining the role of nitric oxide to these processes.We have improved a simple, sensitive assay methods for determination of nitric oxide in blood, tissue, and other body fluids both by fluorometric and by ultraviolet-visible spectrophotometric measurements. Data obtained by floores cence and by UV-visible assay were correlated well (r=0. 9938, P<0. 0001 ).Linearity:0.1￣ 100μmol/L,r =0.9996,P<0.0001. The minimum detection limit were < 10pmol/L. Within-and between-run CVs were 2. 48%and 4. 62% (n = 10),respectively.Reference values for healthy adults(n=40) were(9.82 ± 1. 57) pmol/L. In conclusion:the methods is sensitive, specific,and precise. It is fairly rapid and simple to perform andrequires no pretreatment of sample, i. e., plasma and urine.The value can be obtained by fluorimeter and/or UV-visible spectrophotometer.The present method is sufficiently rapid and simple to make this a practical choice for many laboratories.

An improved algorithm for fluid-structure interaction of high-speed trains under crosswind

Based on the train-track coupling dynamics and high-speed train aerodynamics, this paper deals with an improved algorithm for fluid-structure interaction of high-speed trains. In the algorithm, the data communication between fluid solver and structure solver is avoided by inserting the program of train-track coupling dynamics into fluid dynamics program, and the relaxation factor concerning the load boundary of the fluid-structure interface is introduced to improve the fluctuation and convergence of aerodynamic forces. With this method, the fluid-structure dynamics of a highspeed train are simulated under the condition that the velocity of crosswind is 13.8 m/s and the train speed is 350 km/h. When the relaxation factor equals 0.5, the fluctuation of aerodynamic forces is lower and its convergence is faster than in other cases. The side force and lateral displacement of the head train are compared between off-line simulation and co-simulation. Simulation results show that the fluid-structure interaction has a significant influence on the aerodynam- ics and attitude of the head train under crosswind conditions. In addition, the security indexes of the head train worsen after the fluid-structure interaction calculation. Therefore, the fluid-structure interaction calculation is necessary for high-speed trains.

Effect of Huanglian Jiedu Decoction on vascular endothelium factor and expression of RhoA protein factor in young spontaneously hypertensive rats

To investigate the mechanism of effect of Huanglian Jiedu Decoction(HLJD) on vascular endothelium, we assessed the protective effect of HLJD on vascular endothelium in spontaneously hypertensive rats(SHR) and the expression of RhoA in thoracic aorta. A total of 40 SHR rats were randomly and evenly divided into model group(SHR group), positive group(captopril group), HLJD high-dose group, and HLJD low-dose group. Simultaneously, 10 Wistar Kyoto rats were used in the blank group. All groups were treated by gavage for 6 weeks. The changes of nitric oxide synthase(NOS), von Willebrand factor(vWF), endothelin(ET-1) and calmodulin(CAM) in rat serum were tested by enzyme linked immunosorbent assay(ELISA) method. The expression of RhoA at the protein and mRNA levels in thoracic aorta was determined by Western blotting(WB) and quantitative real-time PCR, respectively. Compare with the blank group after 6 weeks, the levels of ET-l and VWF in serum of the model group were significantly increased(P<0.01), and the levels of NOS and CAM were significantly decreased(P<0.01). Conversely, the levels of ET-1 and vWF in the positive and HLJD groups were significantly decreased(P<0.01 or P<0.05), and the levels of NOS and CAM were significantly increased(P<0.01 or P<0.05) compared with the model group. The expression of Rho A at the mRNA and protein levels was decreased obviously(P<0.05) in HLJD high-dose group. The results shown that HLJD increased diastolic factor(CAM and NOS) in the vascular endothelial of rats, leading to reduced contraction factor(ET-1 and vWF). HLJD revealed the preventive function in the vascular endothelial dysfunction of the early stage hypertension through adjusting secretion of blood vessel endothelium(BVE) relaxing factor and improving vascular endothelial function. The mechanism might be associated with the inhibition of the activity of RhoA protein factor.

Block-Wise ADMM with a Relaxation Factor for Multiple-Block Convex Programming

It has been shown that the alternating direction method of multipliers(ADMM)is not necessarily convergent when it is directly extended to a multiple-block linearly constrained convex minimization model with an objective function that is in the sum of more than two functions without coupled variables.Recently,we pro-posed the block-wise ADMM,which was obtained by regrouping the variables and functions of such a model as two blocks and then applying the original ADMM in block-wise.This note is a further study on this topic with the purpose of showing that a well-known relaxation factor proposed by Fortin and Glowinski for iteratively updat-ing the Lagrangian multiplier of the originalADMMcan also be used in the block-wise ADMM.We thus propose the block-wise ADMM with Fortin and Glowinski’s relax-ation factor for the multiple-block convex minimization model.Like the block-wise ADMM,we also suggest further decomposing the resulting subproblems and regular-izing them by proximal terms to ensure the convergence.For the block-wise ADMM with Fortin and Glowinski's relaxation factor,its convergence and worst-case conver-gence rate measured by the iteration complexity in the ergodic sense are derived.

The functional change of perivascular adipose tissue in hypertensive rats and its mechanisms

Background Recent studies have showed that perivascular adipose tissue （PVAT） may secrete the adventitial-derived relaxing factor （ADRF） to affect vascular function.However,the functional change of ADRF in hypertensive status is seldom studied;and the mechanisms of ADRF remain unclear.Our study examined the ADRF secreted by perivascular adipose tissue of control rats with normal blood pressure （Wistar Kyoto rats,WKY） and discussed the mechanisms of ADRF;We observed the functional change in ADRF of perivascular adipose tissue in spontaneously hypertensive rats （SHRs）.Method The two adjacent thoracic aorta rings of SHR and WKY rats were divided into naked vessel subgroup and PVAT subgroup.The differences of vascular contractility between the two subgroups induced by 10-6 mmol/L phenylephrine were compared.The effect of PVAT culture medium of WKY on the vascular tension of Fat （-） vessels was observed by liquid transfer measure.The mechanism of ADRF was determined by tool drugs.Results In WKY group,vascular contractility of Fat （＋） subgroup was lower than that of the Fat （-） subgroup （P 0.05）;while in SHR group,there was no difference between the two subgroups （P 0.05）.Transferring the incubation solution of WKY Fat （＋） subgroup to the matched Fat （-） subgroup induced rapid vasodilation.When incubating blood vessels in calcium free PSS solution,there was no significant difference of phenylephrine-induced vasoconstriction between Fat （-） and Fat （＋） subgroup.Both glibenclamide,the blocker of ATP-sensitive potassium （KATP） channel and Tetraethy-lammonium chloride （TEA）,the inhibitor of calcium-dependent potassium （KCa） channel,effectively inhibited vasodilation function of ADRF.Conclusions Perivascular adipose tissue in WKY releases ADRF which can cause vasodilation,while this function was inhibited in SHR.ADRF acts through the activation of KCa and KATP channels and calcium ion is involved.

Entry and Exit Stress Variation of Cold Rolling Strip

The shortcomings of an exit stress variation formula which has been well accepted are analyzed~ it is found that the exit stress variation formula violates the premise of the law of volume constancy. The shortcomings of an en- try stress variation formula are analyzed too, and the basic assumption of the formula is uniform exit velocity. How- ever, for a rigid-plastic material uniform exit velocity implies that the lateral distributioi1 of elongation is uniform, so the exit stress must be uniform and any type of flatness defect is impossible, which is contrary to the practice. In fact, entry and exit velocity variation influence entry and exit stress variation, and entry and exit stress variation in- fluence entry and exit velocity variation too, so a precise explicit stress variation formula cannot be got easily. Con- sidering the relationship between stress variation and velocity variation, an iteration method is presented to calculate entry and exit stress variation of cold rolling strip. To avoid divergent phenomenon of the iteration course, a relaxa- tion factor method is adopted. The calculation results are compared with the entry and exit stress variation formula commonly used by many researchers. The difference is remarkable, while the result calculated agree more well with measured result if the exit elastic recovery zone is considered. Specially, the incoming flatnessI propagate efficiency calculated ~ives a more realistic result.

Relaxed inertial proximal Peaceman-Rachford splitting method for separable convex programming

The strictly contractive Peaceman-Rachford splitting method is one of effective methods for solving separable convex optimization problem, and the inertial proximal Peaceman-Rachford splitting method is one of its important variants. It is known that the convergence of the inertial proximal Peaceman- Rachford splitting method can be ensured if the relaxation factor in Lagrangian multiplier updates is underdetermined, which means that the steps for the Lagrangian multiplier updates are shrunk conservatively. Although small steps play an important role in ensuring convergence, they should be strongly avoided in practice. In this article, we propose a relaxed inertial proximal Peaceman- Rachford splitting method, which has a larger feasible set for the relaxation factor. Thus, our method provides the possibility to admit larger steps in the Lagrangian multiplier updates. We establish the global convergence of the proposed algorithm under the same conditions as the inertial proximal Peaceman-Rachford splitting method. Numerical experimental results on a sparse signal recovery problem in compressive sensing and a total variation based image denoising problem demonstrate the effectiveness of our method.