In Vitro Biodegradation of Polyester-Based Plastic Materials by Selected Bacterial Cultures

A simple and rapid in vitro test was designed for the assessment of the biodegradation of polyester-based plastics by selected biodegrading bacterial strains. Variovorax paradoxus LMG 16137 was used for the degradation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Acidovorax avenae subsp. avenae LMG 17238 fo the synthetic-based polyesters poly(-caprolactone) (PCL), poly(butylene succinate-co-butylene adipate), and a starch-PCL blend. Degradation by the bacteria was studied in liquid medium with the plastics (films, granules, and injection-molded test bars) as sole sources of carbon. Degradation was followed through gravimetry, growth of the culture, and tensile testing. The effects of incubation time, inoculum density, aeration, incubation temperature, and pH of the medium on the mass loss were investigated and conditions optimized. The test allowed to obtain reproducible results on the mass loss of plastic samples in less than 3 weeks and yielded excellent partially degraded samples for further analysis.     

Collision and violation involvement of drivers who use cellular telephones

The study sample consisted of 3,869 drivers, split approximately 50/50 between observed cell phone users and those observed not using cell phones (labeled "nonusers"). Cell phone use was determined by a snapshot observation made on city streets. The sample represented 54% of those originally observed, for whom a match was obtained for both vehicle license plate and for gender and estimated age group of the observed driver and that of the driver named in the vehicle policy. Data were obtained from records of insurance claims, police-reported collisions and violations, following a strict protocol to protect individual privacy. The dependent measures were at-fault crash claims and "inattention" violations. A logistic regression model controlled for age, gender, exposure (represented by not-at-fault crash claims), alcohol-related offenses, and aggressive driving offenses. The study also involved a comparison of the contributing factors and collision configurations of police-reported collisions involving the users and "nonusers" in the sample. Drivers observed using cell phones had a higher risk of an at-fault crash than did the "nonusers," although the difference was not significant for males. There was no apparent effect on "inattention" violations. The cell phone users also had a higher proportion of rear-end collisions. The violation pattern of cell phone users suggests that they are, in general, riskier drivers. These differences likely reflect lifestyle, attitude and personality factors. It is essential to control for these factors in assessing the direct risk attributable to cellular telephone use.     

Fetal hypothyroidism as a complication of amiodarone treatment for persistent fetal supraventricular tachycardia

We present a case of persistent fetal supraventricular tachycardia where transplacental and direct fetal treatment with amiodarone caused an iatrogenic hypothyroidism. This condition was successfully managed with the intra-amniotic instillation of 250 μg of L-thyroxine weekly, for 3 weeks. A male infant was delivered at 32 weeks by Caesarean section. The neonatal electrocardiogram showed Wolf-Parkinson-White (WPW) syndrome, which was controlled by digoxin alone. Thyroid function normalized quickly and the baby is developing normally.     

A FLOOD DAMAGE MODEL FOR FLOOD PLAIN STUDIES1

ABSTRACT: Hydrologic and economic information must be integrated in flood plain management. This study describes an integrated approach which includes consideration of the hydrologic, hydrodynamic, physical, and economic components of the total system. On the basis of these components, a theoretical model is proposed which provides a rational procedure for estimating flood damages from projections of economic development within an area. The utility of the model is demonstrated by applying it to a flood-prone region in Southern Quebec, Canada.     

兰州市西固区蔬菜重金属污染现状及健康风险评价研究

针对西北地区典型的工业区-兰州市西固工业区内种植的蔬菜进行重金属含量状况调查分析,对购自当地市场的8种蔬菜中Cu、Cd、Pb、Zn 4种重金属元素的含量进行分析,通过污染指数法和经蔬菜途径重金属暴露接触对人体的健康风险进行了系统评价.结果表明,蔬菜中均不含有Pb元素或Pb元素在蔬菜中的含量比较少,低于分析方法检测限;Cu元素含量最高的是茄子为0.067 mg/kg,含量最低的是菜花为0.015 mg/kg;Cd元素含量最高的是芹菜为0.067 mg/kg,含量最低的是白菜为0.023 mg/kg;Zn元素含量最高的是菠菜为1.001 mg/kg,含量最低的是辣椒为0.274 mg/kg.美国环境健康风险评估方法评价所得THQ值均小于1,表明实验所采集的大多数蔬菜样品的重金属含量符合农产品安全质量要求.     

Sexual selection and reproductive careers in mandrills (Mandrillus sphinx)

In sexually dimorphic, polygynous species, where males provide little parental care and competition between males for access to fertile females is high, sexual selection theory predicts sex differences in age-specific reproductive output and mortality profiles, and greater variance in lifetime reproductive success in males than in females. We examined age-specific reproductive output, mortality patterns and the extent and causes of variation in reproductive success for a semi-free-ranging colony of mandrills (Mandrillus sphinx, Cercopithecidae) in Franceville, Gabon, using long-term (20 year) demographic records and microsatellite parentage analysis. Although differences in the demography and feeding ecology of this closed, provisioned colony, in comparison with wild mandrills, limit interpretation of our results, sex differences in reproductive output and mortality showed the patterns predicted by sexual selection theory. Mortality was higher in males than in females after sexual maturity, and lifespan was significantly shorter in males (mean 14 year) than in females (>22 year). Age at first reproduction was significantly earlier in females (mean 4.2 year) than in males (11.6 year), and male reproductive output declined earlier. All females of breeding age produced offspring; while only 17 of 53 sexually mature males (32%) sired. Males sired a maximum of 41 offspring, versus 17 in females, and variance in male reproductive output was significantly greater than in females at all ages. The most important influence on variation in lifetime reproductive output in both sexes was joint variation between length of the breeding period and reproductive rate, due to lower reproductive rates in younger animals. Finally, social rank significantly influenced reproductive output in both sexes: high-ranking females began their reproductive careers earlier and had a higher subsequent reproductive rate than low-ranking females, while males that achieved top rank during their career sired far more offspring than males that did not.Electronic Supplementary Material Supplementary material is available for this article at     

Competition for the home and aggressive behaviour in the chiton Acanthopleura gemmata (Blainville) (Mollusca: Polyplacophora)

Summary Computerized screening of all the positions recorded during a synodic month on 120 individually marked chitons (Acanthopleura gemmata) pinpointed their preferential resting points. Unlike the majority of intertidal chitons so far studied, A. gemmata rests in well-defined homes actively dug in the rock. Homes proved to be not strictly individual and periodically interchangeable. A complex aggressive behaviour was recorded in the field when two animals came in contact at home. When competing for ownership of a resting site rival chitons may suppress their nocturnal feeding activity. Despite its strong home-related territoriality A. gemmata showed no mutual exclusion on the feeding area. The highly specialized resting habits clearly protects A. gemmata from its most important predator, the toad fish Arothron immaculatus. The behaviour of A. gemmata is compared to that of other chitons and gastropods, and the current hypotheses concerning the adaptive value of the homing behaviour in littoral molluscs are discussed.     

Miscanthus × Giganteus straw and pellets as sustainable fuels

In this paper we present, for the first time, data on the combustion of Miscanthus × Giganteus straw and pellets. We found that the heating value of Miscanthus is 17.744 MJ/kg. The gaseous emission indices of SO₂, NO _x and total organic carbon (TOC) in the exhaust are reported and compared with the European standards for biomass boilers. On the basis of our results, it is possible to evaluate a net energy yield between 152 and 326 MJ/hectare/year for the cultivation of Miscanthus with an energy balance estimated to be in the range of 7.7–15.4. According to the presented results, it seems reasonable to consider Miscanthus as a promising candidate as alternative fuel.     

Cytochrome P4501A induction and testosterone hydroxylation in cultured hepatocytes of four fish species

Primary hepatocytes of the rainbow trout (Oncorhynchus mykiss), flounder (Platychthis flesus), dab (Limanda limanda) and lemon sole (Microstomus kitt) were exposed to 3,3'4,4'5 pentachlorobiphenyl (PCB 126) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for two days. This resulted in a dose-dependent induction of cytochrome P4501A (CYP1A) activity, measured as ethoxyresorufin O-deethylase (EROD), or methoxyresorufin O-deethylase (MROD) activity. In all species, a linear relationship was observed between EROD and MROD activities, suggesting that the same CYP1A enzyme metabolizes the two alkoxy-resorufin substrates. Exposures of hepatocytes of flounder or dab to TCDD, resulted in a 59-fold and 8.2-fold induction of EROD activity, respectively. This did not concur with a change in the in vitro testosterone hydroxylation profiles of both species. These and other in vitro data indicate that TCDD exposure does not influence monooxygenase activities involved in testosterone hydroxylation. Furthermore, CYP1A is of minor importance for testosterone hydroxylation in these fish species.