Piezoelectric Pump Used in Bionic Underwater Propulsion Unit

A new piezoelectric pump can pump liquid either forward or backward and adjust the flow rate. Thus an object can be driven forward or backward at different speeds. The driver of the pump, a circular piezoelectric plate, is modelled by Finite Element Method （FEM） in ANSYS and its performance is simulated and analyzed. The pump gives the best performance when the driving signals of the inlet and outlet valves have a bigger duty cycle and the plate has a higher voltage applied.     

24例人工全膝关节置换术患者手术前后的护理

目的：观察2000年3月至2003年4月人工全膝关节置换术（TKR）患者围手术期进行系统康复训练的护理.方法：选择接受TKR的患者24例30个膝关节,入院后进行术前康复教育和肢体的康复训练（包括肌肉、关节训练及步态训练等）,术后护理包括有针对性的心理护理及系统规范的康复训练.结果：本组术后随访6-12周,效果满意,优良率达95.8%,未发生并发症.结论：TKP患者围手术期间进行系统康复训练,可以减少膝关节并发症,增强膝关节活动范围,满足日常生活所需的关节活动,提高生活质量.     

Mapping the spatial variation of mitral valve elastic properties using air-pulse optical coherence elastography

The mitral valve is a highly heterogeneous tissue composed of two leaflets, anterior and posterior, whose unique composition and regional differences in material properties are essential to overall valve function. While mitral valve mechanics have been studied for many decades, traditional testing methods limit the spatial resolution of measurements and can be destructive. Optical coherence elastography (OCE) is an emerging method for measuring viscoelastic properties of tissues in a noninvasive, nondestructive manner. In this study, we employed air-pulse OCE to measure the spatial variation in mitral valve elastic properties with micro-scale resolution at 1 mm increments along the radial length of the leaflets. We analyzed differences between the leaflets, as well as between regions of the valve. We found that the anterior leaflet has a higher elastic wave velocity, which is reported as a surrogate for stiffness, than the posterior leaflet, most notably at the annular edge of the sample. In addition, we found a spatial elastic gradient in the anterior leaflet, where the annular edge was found to have a greater elastic wave velocity than the free edge. This gradient was less pronounced in the posterior leaflet. These patterns were confirmed using established uniaxial tensile testing methods. Overall, the anterior leaflet was stiffer and had greater heterogeneity in its mechanical properties than the posterior leaflet. This study measures differences between the two mitral leaflets with greater resolution than previously feasible and demonstrates a method that may be suitable for assessing valve mechanics following repair or during the engineering of synthetic valve replacements.     

MicroRNA replacement therapy in cancer

Despite the recent progress in cancer management approaches, the mortality rate of cancer is still growing and there are lots of challenges in the clinics in terms of novel therapeutics. MicroRNAs (miRNA) are regulatory small noncoding RNAs and are already confirmed to have a great role in regulating gene expression level by targeting multiple molecules that affect cell physiology and disease development. Recently, miRNAs have been introduced as promising therapeutic targets for cancer treatment. Regulatory potential of tumor suppressor miRNAs, which enables regulation of entire signaling networks within the cells, makes them an interesting option for developing cancer therapeutics. In this regard, over recent decades, scientists have aimed at developing powerful and safe targeting approaches to restore these suppressive miRNAs in cancerous cells. The present review summarizes the function of miRNAs in tumor development and presents recent findings on how miRNAs have served as therapeutic agents against cancer, with a special focus on tumor suppressor miRNAs (mimics). Moreover, the latest investigations on the therapeutic strategies of miRNA delivery have been presented.     

Identification of 10-dehydrooxyglycyuralin E as a selective human estrogen receptor alpha partial agonist

Selective estrogen receptor modulators (SERMs) act as either agonist or antagonist of estrogen receptor (ER) in a tissue selective manner and have been used in several diseases such as breast cancer, postmenopausal syndrome, osteoporosis, and cardiovascular diseases. However, current SERMs may also increase the risk of serious side effects and trigger drug resistance. Herein, a screening program, that was designed to search for novel SERMs, resulted in the identification of a series of 2-arylbenzofuran-containing compounds that are ligands for ERα, when applying the Gaussia-luciferase reporter assay. One of these compounds, 10-dehydrooxyglycyuralin E (T9) was chemically synthesized. T9 showed anti-estrogenic/proliferative activity in ERα-positive breast cancer cells. Pretreatment of T9 prevented the mRNA expression of GREB1, which is an estrogen response gene. Furthermore, by an in silico docking simulation study we demonstrated that T9 showed interactions directly to ERα. Taken together, these results demonstrated that T9 is a candidate of SERMs and a useful seed compound for the foundation of the selective activity of SERMs.     

An investigation of residue-specific contributions to peptide desorption in MALDI-TOF mass spectrometry*

*Work supported by DGICYT (Grant PB94-0845) and by Generalitat de Catalunya (Centre de Referència de Biotecnologia.The MALDI-TOF mass spectra of a set of 240 analogs of the pentadecapeptide YTASARGDLAHLTTT, displaying single point replacements with all amino acids except Met, Cys and Trp, have been used to study the contribution of individual residues to peptide desorption. Replacements with non-polar aliphatic (except Ala) or aromatic residues at most positions tend to reinforce ion signals relative to the cognate sequence. Among polar residues, Arg shows also a clear tendency to enhance signal intensity at most positions. The responses recorded for replacements with a given amino acid can be averaged and normalized to give a mean response index, _m, which qualitatively expresses the relative contribution of that residue to the desorption of a generic peptide. HPLC analysis of the replacement set does not support a significant role of residue hydrophobicity in peptide desorption. The unique role of Arg in promoting peptide desorption may be related to a better stabilization of peptide-matrix adducts through guanidinium-carboxylate interaction.     

Chromosomal promoter replacement in Saccharomyces cerevisiae: Construction of conditional lethal strains for the cloning of glycosyltransferases from various organisms

Heterologous complementation in yeast has been a successful tool for cloning and characterisation of genes from various organisms. Therefore we constructed conditionally lethal Saccharomyces cerevisiae strains by replacing the endogenous promoter from the genes of interest (glycosyltransferases) by the stringently regulated GAL1-promoter, by a technique called chromosomal promoter replacement. Such yeast strains were constructed for the genes Alg 1, Alg7, Sec59, Wbp1 involved in N-Glycosylation, the genes Gpi2, Gpi3/Spt14, Gaal, Pis1, involved in GPI-anchor biosynthesis and Dpm involved in both pathways. All strains show the expected conditionally lethal phenotype on glucose-containing medium when expression of the respective gene is turned off.     

Size-dependent male–male competition for a spawning substrate between <Emphasis Type="Italic">Pseudorasbora parva</Emphasis> and <Emphasis Type="Italic">Pseudorasbora pumila</Emphasis>

Pseudorasbora parva, a species native to western Japan, has been accidentally introduced into eastern Japan, where P. pumila is indigenous. We investigated inter- and intraspecific, male–male competition between P. parva and P. pumila for acquisition of spawning substrates in an experimental setting. Within each species, males of larger standard length and heavier body weight were more successful in acquiring a substrate. Males of the two species competed, but the outcome was determined primarily by body weight. This interspecific, size-dependent, male–male competition might be an important factor in the species replacement of P. pumila by P. parva.     

A reverse genetic approach for generating gene replacement mutants in<Emphasis Type="Italic"> Ustilago maydis</Emphasis>

We describe a versatile strategy for generating gene replacement mutants in the phytopathogenic fungus Ustilago maydis. The system includes the choice of 32 different insertion cassettes for genetic engineering purposes, such as gene disruption and more sophisticated insertions of reporter genes, heterologous promoters or combinations of the two. PCR-amplified flanking sequences needed for homologous recombination are ligated to the respective insertion cassettes via Sfi I sites. As proof of principle we generated two replacement mutants in which the endogenous promoter of the pheromone gene mfa1 drives expression of the Green Fluorescent Protein gene (gfp). Simultaneously, expression of the mfa1 ORF is controlled either by the carbon source-regulated crg1 promoter or the nitrogen source-regulated nar1 promoter. In both cases gfp expression was pheromone-inducible and pheromone expression was only detected when the heterologous promoters were active.Communicated by G. JürgensThe first two authors contributed equally to this work