Effect of physical parameters in enhancing prodigiosin production and anti-MRSA activity of marine bacterium, Serratia marcescens IBRL USM84

Aims@#Marine bacteria have been reported to produce potential natural pigment with pharmaceutical properties and their growth can be manipulated in the laboratory to increase pigment production and their antimicrobial activity. Hence, this study aimed to enhance the prodigiosin production in Serratia marcescens IBRL USM84 by improving physical conditions.@*Methodology and results@#The quantification of the pigment produced by S. marcescens IBRL USM84, bacterial cell growth, and its antibacterial activity in the broth medium were determined using a spectrophotometry method. Meanwhile, the antibacterial effect of red pigment on MRSA cells was observed under a scanning electron microscope (SEM). This marine isolate produced the highest yield of prodigiosin (6.95 μg/mL) when cultivated in marine broth with the addition of 0.2% of agar, 25 °C incubation temperature, initial medium pH of 7, 150 rpm of agitation speed for 48 h of cultivation time under light illumination. There was an increment of 151.81% in prodigiosin production after enhancement compared to before the enhancement of cultural conditions. SEM observations revealed that severe damage to the cell’s morphologies was exposed to red pigment as indicated by the formation of small dents, which led to completely collapse and eventually, cell death.@*Conclusion, significance and impact of study@#A positive correlation between pigment production and antibacterial activity was observed in the present study. The results supported the fact that marine bacteria are a reservoir of various pigments with antimicrobial properties. Also, the pigment production by S. marcescens and its antibacterial activity were significantly influenced by physical parameters.

Research progress on effects of radio frequency radiation and its physical parameters on male reproductive system / 环境与职业医学

With the widespread use of mobile phones, laptops, and WIFI, the effects of radio frequency radiation (RFR) on human health are of increasing concern, and there are particular concerns about its reproductive toxicity. Studies have shown that the reproductive system is a sensitive target for RFR. In males, RFR is associated with decreased sperm quality and serum testosterone levels, but there are few studies on the biological effects of RFR by altering physical parameters on the male reproductive system. This paper introduced common sources of RFR, reviewed the toxic effects and mechanisms of RFR targeting male reproductive system from the aspects of spermatogenic cells, sperm structure, blood-testicular barrier, and testicular function, and analyzed male reproductive system related toxic effects of RFR by varying physical parameters including frequency, treatment duration, and specific absorption rate, so as to provide a theoretical basis and scientific basis for the safe and reasonable use of radio frequency electromagnetic field by humans and subsequent in-depth research.

Study result of the anxiety among abused child and adolescents / Монголын Анагаах Ухаан

Background. The abuse experiences can change the normal development of the child with the consequences being visible after many years even throughout the whole life. The relation between childhood abuse and the psychiatric disorder in adulthood is reported in a great number of epidemiological studies and researches based on the clinical population surveillance. Numerous studies have significantly expressed the relation between childhood abuse and anxiety, the development of anxiety disorders. Limited research has shown a possible association between exposures to child abuse the risk of developing physical parameter changes as an adult.Goal. To study anxiety and some physical parameters among abused adolescentsMaterials and Method. There were selected46 abused children and 48 non abused children aged between 11-16 years old. The Spence Children’s Anxiety Scale (SCAS; Spence, 1997) is a38-item selfreport questionnaire that assesses multiple symptoms of childhood anxiety disorders based on current diagnosticcriteria. The height, weight, heart rate, breath rate and blood pressure of all participants in the study were measured according to standardized methodology.Results. Average age of all subjects in the study was13.51±1.61 and 60% of them were female and 41% male. All anxiety symptoms of case group was statistically significance higher (p<0.01) than the control group. Significantly more abused children (147.09±10.16) showed stunting compared to 4 sm of non-abused (151.53±10.26).Conclusion. In the present study, abused children were 2.8 times as likely as children with no maltreatment. Also significant stunting was found among abused children identified does differ from the growth of children who are not abused.

A comparative study on the propagation speed and physical parameters of underwater blast wave and air blast wave / 解放军医学杂志

Objective To compare the propagation speed and physical parameters between underwater blast wave and air blast wave. Methods The physical parameters of blast wave were measured by PCB pressure transducers (USA) during underwater and air explosions of 200g, 500g and 1000g TNT respectively. Consequently, the propagation speed, peak overpressure value, positive duration and impulse of blast wave were analyzed. Results Underwater blast wave was characterized by high propagation speed, high peak overpressure value, great impulse, however, short duration. Compared with air blast wave, the propagation speed of underwater blast wave was 3.70-4.30 times higher than that of air blast wave, the peak overpressure value was 227.15-247.86 times higher, and the impulse was 8.48-11.80 times greater than that of air blast wave. Conclusion Underwater blast wave propagates faster than that air blast wave. Meanwhile, it also peoduces higher peak overpressure value and impulse. This result is helpful for the evaluation of injury severity and treatment of underwater blast injury.