Effect of experimental varicocele on structure and function of epididymis in adolescent rats

<abstract>Aim: To study the effect of experimental left varicocele (ELV) on epididymal structure and function in adolescent Sprague-Dawley rats. Methods: ELV was induced by partial ligation of the left renal vein. Sham-operated animals served as the controls. Four and 8 weeks after the operation, the histological, ultrastructural and biochemical (alpha-glucosidase activity and carnitine content) changes in different segments of the epididymis were observed. Results: In the treated animals, there were degeneration of the epididymal epithelium and edema of the interstitial tissue; numerous shedding cells, residual bodies, deformed sperm and macrophages appeared in the epididymal lumen. Morphometric measurement indicated a significant reduction in the epididymal tubular diameter (P<0.05) and a significant increase in the epididymal interstitial area (P<0.05) compared with the controls. Ultrastructural study showed sparse microvilli of the columnar epithelium, increased and enlarged lysosomes in the principal cells with defected organelles and the presence of large cytoplasmic vacuoles. The protein and carnitine contents and the alpha-glucosidase activity in the caput, corpus and cauda epididymis of the ELV rats were lower than those of the controls (P< 0.05). Conclusion: There were structural and functional changes in the epididymis of adolescent ELV rats, which may contribute to the infertility caused by varicocele.

STUDY ON PHASE PERCEPTION IN SPEECH

The perceptual effect of the phase information in speech has been studied by auditorysubjective tests. On the condition that the phase spectrum in speech is changed while amplitudespectrum is unchanged, the tests show that: (1) If the envelop of the reconstructed speech signalis unchanged, there is indistinctive auditory perception between the original speech and thereconstructed speech; (2) The auditory perception effect of the reconstructed speech mainly lieson the amplitude of the derivative of the additive phase; (3) td is the maximum relative time shiftbetween different frequency components of the reconstructed speech signal. The speech qualityis excellent while td ＜10ms; good while 10ms＜ td ＜20ms; common while 20ms＜ td ＜35ms, andpoor while td ＞35ms.

MICROSTRUCTURE AND PROPERTIES OF CuCr25 ALLOYS WITH DIFFERENT Ni CONTENT

CuCr25 alloys containing different Ni content were prepared by vacuum induction melting (VIM). The micro structure and properties were tested. The results show that with the increase of Ni content in CuCr25 alloys, the Cr phase changed from developed dendrite into nodular grains and was drastically refined; the electrical conductivity significantly decrease, but still reach the level of conventional CuCr50 when the Ni content is below 0.5%. The Ni content had little influence on their breakdown strength. The first breakdown sites transferred to the boundary of Cu and Cr phase for CuCr25Ni compared to the Cr phase for CuCr25 without Ni.

A Study on Turbo-rotor Multi-fault Diagnosis Based on a Neural Network

The multi-fault phenomena are common in the turbo-rotor system of a liquidrocket engine. As it has many excellent qualities, the neural network might be used to solve theproblems of multi-fault diagnosis of a turbo-rotor system. First, the feature expression of a commonturbo-rotor fault was studied in order to build up the standard fault pattern and satisfy the needof neural network studying and diagnosing. Then, the turbo-rotor fault identification and diagnosisproblems were investigated by using a BP( back-propagation) neural network. According to the BPneural network problems, the parallel BP neural network method of multi-fault diagnosis andclassification was presented and investigated. The results indicated that the parallel BP neuralnetwork method could solve the turbo-rotor multi-fault diagnosis problems.

Group—Invariant Solutions in Plane Curve Motions

Group-invariant solutions to certain plane curve motions in Euclidean and centro-affine geometries areobtained. The behavior of some solutions is also presented.

Electrochemical Synthesis and Absorption Properties of Gold Nanorods

Suspended gold nanorods have been synthesized via an electrochemical method.The absorption spectrum features show two peaks at 520nm and 650nm,which result from the transverse and longitudinal surface plasmon resonance.The spectra at different growth stages indicate that the absorption peaks split and shift after electrolysis,which correspond to the anisotropy growth of nanorods.The quasi-static calculation results indicate that with increasing the mean aspect ratio of the nanorods,the longer wavelength absorption peak decreases and red shifts obviously,whereas the shorter wavelength absorption peak blue shifts slightly.

Development of centrifugal casting high speed steel rolls

The present study aims at developing the high speed steel (HSS) as rollmaterials to replace the traditional roll materials such as the alloy cast iron and powdermetallurgical (PM) hard alloy. The HSS roll billet was formed by centrifugal casting, and the billetwas rough machined alter soften annealing heat treatment, then it was quenched and tempered to getsuitable hardness and toughness. After that the HSS roll was finish machined to the final dimensionof phi 285 mm in the outer diameter, phi 160 mm in the inner diameter and 120 mm in width and itssurface hardness was tested. Finally the HSS roll was used in high speed wire rod mill. The testresults show that a high and homogeneous hardness can obtain on the work surface of HSS rolls, thesurface hardness is 63-65HRC and its variation is smaller than 2HRC. The impact toughness of thiskind of HSS is about 16 J/cm^2. The results of on-line service investigation in high speed wire rodmill indicate that the HSS rolls have excellent wear resistance, the steel rolling quantity per mmof HSS rolls is 3120 t, the service life-span of HSS rolls is 4 times longer than that of highchromium cast iron rolls and it is close to that of the PM hard alloy rolls. The manufacturingburden of HSS rolls is obviously lower than that of the PM hard alloy rolls, it is only 25 percentof that of the PM hard alloy rolls.

Construction of Compactly Supported Bivariate Orthogonal Wavelets

For a given compactly supported scaling fun ct ion supported over [0,3]×[0,3], we present an algorithm to construct compac t ly supported orthogonal wavelets. By this algorithm, the symbol function of the associated wavelets can be constructed explicitly.

Preparation and Characterization of Polyimide Attached with Azo-dye Chromophore Side Chain

In order to improve the nonlinear optical property and stability of azo-dye chromophore, the nonlinear optical polyimide (NLOPI) attached with azo chromophore side chain is synthesized by diazo coupling reaction of 4-nitrobenzenediazonium tetrafloroborate. The designed chemical structure of production can be proved in the infrared spectrum and ultraviolet-visible absorption spectrum. The NLOPI exhibited UV-Vis absorption of the azobenzene chromophore in the vicinity of the wavelengths of 330 and 490 nm. The broad amorphous peak proved that the NLOPI was amorphous with a little periodical structure along the side chain. According to transmission electron microscope, the NLOPI film was homogeneous. NLOPI only displayed a decrease in mass of about 5% at the temperature of 400 ℃ through thermogravimetric analysis.

Different Effects of Topical Prazosin and Pilocarpine on Uveoscleral Outflow in Rabbit Eyes

Purpose: To investigate the effects of topical prazosin and pilocarpine on uveoscleral outflow(Fu) in rabbits.Methods: Sixteen rabbits were randomly divided into the control group (5 rabbits, only topical application of normal saline in the right eye of each rabbit), Prazosin (PZ) treated group (6 rabbits, only 0.1% Prazosin eyedrop 0.1% in the right eye of each one) and Pilocarpine (PC) treated group (5 rabbits, 1% Pilocarpine eye drop in each right eye).Intraocular pressure (IOP)of bilateral eyes of each rabbit was measured before and 1 h after topical application of the eye drop.And the bilateral eyes were perfused with Fluorescein-isothiocyanate bovine serum albumin (FITC-BSA) as the tracer into the anterior chamber of each rabbit for 30 min at 90 min after topical treatment. Then the rabbits were killed for Fu measurement.Results: IOP of PZ-treated eyes decreased [ (0.71 +0.07)kPa ] in 1 hour after PZ application.IOP of PC-treated eyes decreased [(0.70+0.08)kPa] in 1 hour after PC application. The average value of Fu was (0.176+0.048)μl/min in control eyes. The average value of Fu in PZ-treated eyes was (0.339+0.018)μl/min. The average value of Fu in PC-treated eye was(0.123+0.022) μl/min.Conclusion: Both of PZ and PC can decrease IOP in rabbits following topical application.Topical PZ can increase Fu in rabbits and this is one of the mechanisms of PZ-induced IOP decrease.Topical PC can prevent Fu. PC decreases IOP not through uveoscleral pathway.This study demonstrates that uveoscleral pathway plays an important role in aqueous humor drainage. PZ may be a novel drug for decreasing IOP. FITC-BSA is an effective tracer for studying uveoscleral pathway.

APPLICATION OF TWO VERSIONS OF A RNG BASED k-ε MODEL TO NUMERICAL SIMULATIONS OF TURBULENT IMPINGING JET FLOW

Two independent versions of the RNG based k ε turbulence model in conjunction with the law of the wall have been applied to the numerical simulation of an axisymmetric turbulent impinging jet flow field. The two model predictions are compared with those of the standard k ε model and with the experimental data measured by LDV (Laser Doppler Velocimetry). It shows that the original version of the RNG k ε model with the choice of C ε1 =1.063 can not yield good results, among them the predicted turbulent kinetic energy profiles in the vicinity of the stagnation region are even worse than those predicted by the standard k ε model. However, the new version of RNG k ε model behaves well. This is mainly due to the corrections to the constants C ε1 and C ε2 along with a modification of the production term to account for non equilibrium strain rates in the flow.

The Structural Characterization and Antigenicity of the S Protein of SARS-CoV

The corona-like spikes or peplomers on the surface of the virion under electronic microscope are the most striking features of coronaviruses. The S (spike) protein is the largest structural protein, with 1,255 amino acids, in the viral genome. Its structure can be divided into three regions: a long N-terminal region in the exterior, a characteristic transmembrane (TM) region, and a short C-terminus in the interior of a virion. We detected fifteen substitutions of nucleotides by comparisons with the seventeen published SARS-CoV genome sequences, eight (53.3%) of which are non-synonymous mutations leading to amino acid alternations with predicted physiochemical changes. The possible antigenic determinants of the S protein are predicted, and the result is confirmed by ELISA (enzyme-linked immunosorbent assay) with synthesized peptides. Another profound finding is that three disulfide bonds are defined at the C-terminus with the N-terminus of the E (envelope) protein, based on the typical sequence and positions, thus establishing the structural connection with these two important structural proteins, if confirmed. Phyloge-netic analysis reveals several conserved regions that might be potent drug targets.

STABILITY OF VORTEX STREET IN GAS-LIQUID TWO-PHASE FLOW

The stability of the Karmen vortex street in gas-liquid two-phase flow wasstudied experimentally and theoretically. The values of the parameter h/l characterizing the vortexsirect structure (i. e. , the ratio of the vortex street width to the distance between two vortexes)for a stable vortex street in gas-liquid two-phase flow were obtained for the first lime. Theparameter h/l was proved to be a variable, not a constant as in single-phase flow, h/l is related tothe upstream fluid void fraction. In gas-liquid two-phase fluid flow to form a steady vortex streetis more difficult than in a single-phase fluid flow. Because in the unsteady vortex shedding thevortex shedding band frequency is broader than the one in the single phase fluid flow, so it iseasier to induce the cross-cylinder resonance than in the single phase fluid flow, and this caseshould give rise to the attention of engineers.

CHAOTIC HYDRODYNAMICS IN HORIZONTAL GAS-LIQUID BUBBLY FLOW

To investigate the non-linear hydrodynamics in horizontal gas-liquid bubblyflow, time-series data of local void fraction were obtained using a double sensor probe. Bothdeterministic chaos and stochastic analyses were used to diagnose the dynamic behaviors in thesystem. The power spectra of the local void fraction exhibited no single distinct peak, indicatingthe aperiodic nature of the variation of the local void fraction. The kolmogorov entropy andcorrelation dimension of the attractor reconstructed from the time-series data by the embeddingmethod were to be positive and very large, the Hurst exponent computed from the rescaled rangeanalysis was found to be larger than 0. 5, indicating the non-linear chaotic feature of the system.The Kolmogorov entropy and the correlation dimension decrease with increasing liquid superficialvelocity, and the correlation dimension changes less if the gas superficial velocity is high. On theother hand, the fluctuation of local void fraction in horizontal gas-liquid bubbly flow could beconsidered to take place due to the zigzag motion of bubbles with different shape, size andvelocity.

The R Protein of SARS-CoV: Analyses of Structure and Function Based on Four Complete Genome Sequences of Isolates BJ01-BJ04

The R (replicase) protein is the uniquely defined non-structural protein (NSP) responsible for RNA replication, mutation rate or fidelity, regulation of transcription in coronaviruses and many other ssRNA viruses. Based on our complete genome sequences of four isolates (BJ01-BJ04) of SARS-CoV from Beijing, China, we analyzed the structure and predicted functions of the R protein in comparison with 13 other isolates of SARS-CoV and 6 other coronaviruses. The entire ORF (open-reading frame) encodes for two major enzyme activities, RNA-dependent RNA polymerase (RdRp) and proteinase activities. The R polyprotein undergoes a complex proteolytic process to produce 15 function-related peptides. A hydrophobic domain (HOD) and a hydrophilic domain (HID) are newly identified within NSP1. The substitution rate of the R protein is close to the average of the SARS-CoV genome. The functional domains in all NSPs of the R protein give different phylogenetic results that suggest their different mutation rate under selective pressure. Eleven highly conserved regions in RdRp and twelve cleavage sites by 3CLP (chymotrypsin-like protein) have been identified as potential drug targets. Findings suggest that it is possible to obtain information about the phy-logeny of SARS-CoV, as well as potential tools for drug design, genotyping and diagnostics of SARS.