Antibacterial activity of a marine bacterium against pathogenic and environmental isolates of vibrio species

The marine environment covers three quarters of the surface of the planet is estimated to be home to more than 80% of life and yet it remains largely unexplored. The rich diversity of marine flora and fauna and its adaptation to the harsh marine environment coupled with new developments in biotechnology, has opened up a new exciting vista for extraction of bioactive products of use in medicine. In this study inhibitory activity of a marine bacterium isolated from gut of ribbonfish was studied against pathogenic and environmental isolates of Vibrio species. This strain was identified as Pseudomonas stutzeri and it was found active against V. harveyi (luminescent bacteria), V. cholerae, V. alginolyticus, V. damseal, V. fluvialis. The antibacterial substance produced by Pseudomonas stutzeri was soluble in organic solvent and closely bound to external surface of bacterial cells. Reduction of the absorbance of the V. cholera cell suspension was observed when log phase cells of V. cholerae were treated with MIC and 4xMIC concentration of crude extract of Pseudomonas stutzeri.

Multidirectional scattering models for 3-dimensional ultrasound imaging

An ultrasound image is created from backscattered echoes originating from both diffuse and directional scattering. It is potentially useful to separate these two components for the purpose of tissue characterization. This article presents several models for visualization of scattering fields on 3-dimensional (3D) ultrasound imaging. By scanning the same anatomy from multiple directions, we can observe the variation of specular intensity as a function of the viewing angle. This article considers two models for estimating the diffuse and specular components of the backscattered intensity: a modification of the well-known Phong reflection model and an existing exponential model. We examine 2-dimensional implementations and also propose novel 3D extensions of these models in which the probe is not constrained to rotate within a plane. Both simulation and experimental results show that improved performance can be achieved with 3D models. © 2013 by the American Institute of Ultrasound in Medicine.

Mechanical behaviour of electrospun fibre-reinforced hydrogels

Mechanically robust and biomimicking scaffolds are needed for structural engineering of tissues such as the intervertebral disc, which are prone to failure and incapable of natural healing. Here, the formation of thick, randomly aligned polycaprolactone electrospun fibre structures infiltrated with alginate is reported. The composites are characterised using both indentation and tensile testing and demonstrate substantially different tensile and compressive moduli. The composites are mechanically robust and exhibit large strains-to-failure, exhibiting toughening mechanisms observed in other composite material systems. The method presented here provides a way to create large-scale biomimetic scaffolds that more closely mimic the composite structure of natural tissue, with tuneable tensile and compressive properties via the fibre and matrix phases, respectively. © 2014 Springer Science+Business Media New York.

The development of long - Term ambulatory pH monitoring system and its clinical application

This paper introduced a long-term ambulatory intragastric pH monitoring system, which is designed for prolonged ambulatory studies of Gastroesophageal Reflux Diseases. The whole system is composed of the gastric catheter with two pH sensors, a small data logger (Microdatalog), and a notebook PC. In this paper, the design of monitoring system hardware and software are described in detail. Clinical applications reveal good results.

Simulations to design an online motion compensation system for scanned particle beams

Respiration-induced target motion is a major problem in intensity-modulated radiation therapy. Beam segments are delivered serially to form the total dose distribution. In the presence of motion, the spatial relation between dose deposition from different segments will be lost. Usually, this results in over-and underdosage. Besides such interplay effects between target motion and dynamic beam delivery as known from photon therapy, changes in internal density have an impact on delivered dose for intensity-modulated charged particle therapy. In this study, we have analysed interplay effects between raster scanned carbon ion beams and target motion. Furthermore, the potential of an online motion strategy was assessed in several simulations. An extended version of the clinical treatment planning software was used to calculate dose distributions to moving targets with and without motion compensation. For motion compensation, each individual ion pencil beam tracked the planned target position in the lateral aswell as longitudinal direction. Target translations and rotations, including changes in internal density, were simulated. Target motion simulating breathing resulted in severe degradation of delivered dose distributions. For example, for motion amplitudes of +/- 15 mm, only 47% of the target volume received 80% of the planned dose. Unpredictability of resulting dose distributions was demonstrated by varying motion parameters. On the other hand, motion compensation allowed for dose distributions for moving targets comparable to those for static targets. Even limited compensation precision (standard deviation similar to 2 mm), introduced to simulate possible limitations of real-time target tracking, resulted in less than 3% loss in dose homogeneity.

Large-scale isolation and purification of R-phycoerythrin from red alga Palmaria palmata using the expanded bed adsorption method

R-phycoerythrin, a light-harvesting protein in some marine algae, and can be widely used in medicine, was isolated and purified from a red alga, Palmaria palmata (Lannaeus) Kuntze, using the streamline column (expanded bed adsorption) combined with ion-exchange chromatography. Because the crude extract was applied to the column upwardly, the column would not be blocked by polysaccharides usually very abundant in the extract of marine alga, this kind of blockage could hardly lie overcome in ordinary chromatographic column. After applying the crude extract containing 0.5 mol/L (NH4)(2)SO4, (NH4)(2)SO4 solution of different concentrations (0.2 mol/L, 0.1 mol/L and 0.05 mol/L) was used to elute the column downwardly and the eluates were collected and desalted. The desalted eluates were then applied onto all ion-exchange chromatographic column loaded with Q-sepharose for further purification of the R-phycoerythrin. Through these two steps, the purity (OD565/OD280) of the R-phycoerythrin from P. palmata was up to 3.5, more than 3.2, the commonly accepted criterion for purity, and the yield of the purified R-phycoerythrin could reach 0.122 mg/g of frozen P. palmata, much higher than that of phycobiliproteins purified with the previous methods. The result indicated that the cost of R-phycoerythrin will drop down with the method reported in this article.

中学生抑郁和素质、压力、环境因素的关系及其整合模型研究

As a kind of mood, depression is one of the emotions which people experienced usually. Depressive disorder is one of the common mental diseases. There are about 100 million people in the world be disturbed by depression every year. So it is long history that depression is investigated widely in medicine, psychology, and sociology. There are many theorial problems remain to be solved. Viewed from latest vocuments, the development of depression theory is tending to become more complicated. Most of the prior depression theory focused on relation between one factor and depression. Because depressed individuls have various characteristics and factors that cause depression are different, and each factor can explain only part of depression variance, these prior depression theories are defected. As the knowledge about depression accumulated, the view that depression be caused by multifactor is clearer. There is tendency to integrate these cooperational factor into a model while developing a depression theory. In the present study, depression status of 1625 middle school students from junior 1 to senior 3 are measured using Depression Scale of Middle-school Student which is developed by ourselves. From approach of depressive mood, the present study explored depressive diathesis including attributional style, personality, coping style, and self. The relation among depressive diathesis, stress and depression is analysed. The relation between depression and school life adaptation, depression and cohesion, adaptation in family are also analysed from environmental view. At last, relation among environment, stress, depressive diathesis is examined by using covariance structure modelling. Synthesizing the results from the present study, the following conclusions were drawn: (1) There is grade-characteristics in development of depression in middle school students. Depression degree increased with grade. The main reason may be that the stress middle-school students experience increase and self-acceptance decrease with grade; (2) High depressive diathesis is different from low depressive diathesis. the features of high depressive diathesis are that attributing failure to ability or background, low capacity for status, low sociability, low independence, low self-blame, more illusion. The features of low depressive diathesis are that not attributing failure to ability or background, high capacity for status, high sociability, high independence, high self-acceptance, while facing difficulties, using problem-resolving coping strategy, less self-blame, less illusion. Individuals who have high depressive diathesis showed serious depression, and individuals who have low depressive diathesis showed light depression; (3) Depressive diathesis had accumulative effect on depression. More low depressive diathesis, more light is depression. More high depressive diathesis, more serious is depression; (4) Depressive diathesis can predict present depression and future depression. Predicting present depression is more effective than predicting future depression; (5) Individual who has different depressive diathesis experiences different level of stress. Higher the depressive diathesis individual has, higher stress he will experience. Lower the depressive diathesis individual has, lower stress will he experience; (6) There is correlation between life event pressure and depression. Life event pressure can predict a part of variance of depression. Life event pressure has accumulative effect on depression. More life event and higher life event pressure, more serious depression individual will experience; (7) There exits high correlation between depression and school life adaptation which can predict depression; (8) There is high correlative relation between depression and cohesion, adaptation in family which can predict depression; and (9) Environment have more effect on diathesis than on stress. Diathesis has more effect on depression than stress does. The past depression can predict future depression. This study had enlarged the domain of depressive diathesis such as attributional style, personality, coping style, and self, which are analysed wholly. This study had also enriched the connotation of diathesis=stress theory. Above two aspects are theoretical significance of the study. This study provide a framework of mental health educational curriculum in high school and provide the guideline for prevention and cure of depression. It is the practical significance of this study.