Air Filtration and Radon Decay Product Mitigation

Air cleaning as a means of mitigating the risks arising from exposure to indoor radon progeny has been evaluated in a single-family house in the north eastem US. using an automated, semi-continuous activity-weighted size distribution measurement system. The measurements included radon concentration, condensation nuclei count, and activity-weighted size distribution of radon decay products. Measurements were made in the house with and without an operating air filtration system and with various particle sources common to normal indoor activities operating. Aerosols were generated by running water in a shower, candle burning, cigarette smoking, vacuuming, opening doors, and cooking. Using a room model, the changes in attachment rates, average attachment diameters, and deposition rates of the unattached fraction with and without the air cleaning system were calculated. In the presence of active aerosol sources, the air filtration unit typically reduced the concentration of particles within the hour following the end of particle generation. After candle burning, cigarette smoking, and vacuuming in the bedroom, the reductions of PAEC by air filtration are about 60% with the air filtration system operating in the bedroom. During cooking in the kitchen, the reductions of PAEC in the bedroom with the air filtration system were about 40%. However, for all cases the dose reductions were smaller than the particle and PAEC reductions. For those particles that were generated within the bedroom, there was a 20% to 50% reduction in dose. In the case of cooking where the door was open and particles infiltrated from the rest of the house, the dose reduction was only 5% on average and appears to be insignificant. Thus, the dose reductions were h e r than the reductions in activity concentration, but there were no cases where the estimated dose actually increased.     

Causes of Decay of Fresh-cut Celery

A decay of fresh-cut celery (Apium graveolens) segments stored at < 5°C in sealed film bags began with a water soaking of the cut surfaces. Slimy moisture accumulated inside the bags. The segments water soaked completely, softened, discolored and sometimes disintegrated. Total aerobic bacterial populations isolated from decayed segments ranged from log₁₀ 7.0–7.7 CFU/g tissue weight. The predominant bacteria, identified by fatty acid analysis as Pseudomonas fluorescens and P. marginalis, caused water soaking, soft rot, and discoloration in freshly inoculated celery tissues stored at 5 or 25°C. Leuconostoc mesenteroides was also isolated and may have been responsible for slime production.     

Commentary on Krishnaswamy et al. - Quantifying and mapping biodiversity and ecosystem services: Utility of a multi-season NDVI based Mahalanobis distance surrogate

Remote sensing is a powerful tool for characterizing, estimating or modelling species diversity. Differences in environmental properties of different habitats should lead to differences of spectral responses, which can be detected by satellite imagery. Hence, spectral distance may be related to species diversity. Based on previous studies, Krishnaswamy et al. [Krishnaswamy, J., Bawa, K. S., Ganeshaiah, K. N., & Kiran, M. C. (2009). Quantifying and mapping biodiversity and ecosystem services: Utility of a multi-season NDVI based Mahalanobis distance surrogate. Remote Sensing of Environment.] used spectral distance to estimate species diversity. Since a noisy scatterplot of species versus spectral diversity is expected, the commonly used Ordinary Least Square regression may fail to detect trends which occur across other quantiles than the mean.Krishnaswamy et al. [Krishnaswamy, J., Bawa, K. S., Ganeshaiah, K. N., & Kiran, M. C. (2009). Quantifying and mapping biodiversity and ecosystem services: Utility of a multi-season NDVI based Mahalanobis distance surrogate. Remote Sensing of Environment.] proposed a quantile-quantile plot method as an alternative to conventional regression based approaches which are inappropriate for dependent pair-wise dissimilarity or similarity data. By this commentary I demonstrate the utility of a quantile regression technique to complement the Krishnaswamy et al. [Krishnaswamy, J., Bawa, K. S., Ganeshaiah, K. N., & Kiran, M. C. (2009). Quantifying and mapping biodiversity and ecosystem services: Utility of a multi-season NDVI based Mahalanobis distance surrogate. Remote Sensing of Environment.] graphical approach in terms of a predictive model.     

Stochastic stabilization of differential systems with general decay rate

Some sufficient conditions concerning stability of solutions of stochastic differential evolution equations with general decay rate are first proved. Then, these results are interpreted as suitable stabilization ones for deterministic and stochastic systems. Also, they permit us to construct appropriate linear stabilizers in some particular situations.     

Optical properties of CdSe quantum dots grown on ZnSe and ZnBeSe by molecular beam epitaxy

We report detailed studies of the optical properties of CdSe quantum dots (QDs) grown on ZnSe and ZnBeSe by molecular-beam epitaxy (MBE). We performed steady-state and time-resolved photoluminescence (PL) measurements and observe that nonradiative processes dominate at room temperature (RT) in the CdSe/ZnBeSe QDs structures, though these nonradiative processes do not dominate in the CdSe/ZnSe QDs structures up to RT. We performed secondary ion-mass spectrometry (SIMS) measurement and propose that the oxygen incorporation in the ZnBeSe layers (possibly caused by the reactivity of Be) may contribute to the dominant nonradiative processes at high temperatures in the QDs grown on ZnBeSe.     

单色光光电导衰减法测试硅单晶少子寿命的表面复合修正公式

本文在数值分析和实验数据的基础上，提出了用单色光高频光电导衰减法测量硅单晶少子寿命的表面复合修正公式。     

Biocontrol of postharvest gray and blue mold decay of apples with Rhodotorula mucilaginosa and possible mechanisms of action

The efficacy of Rhodotorula mucilaginosa against postharvest gray mold, blue mold and natural decay development of apples and the possible mechanisms involved were investigated. The decay incidence and lesion diameter of gray mold and blue mold of apples treated by R. mucilaginosa were significantly reduced compared with the control fruits, and the higher concentration of R. mucilaginosa, the better the efficacy of the biocontrol. R. mucilaginosa also significantly reduced the natural decay development of apples following storage at 20 °C for 35 days or at 4 °C for 45 days followed by 20 °C for 15 days. Germination and survival of spores of Penicillium expansum and Botrytis cinerea were markedly inhibited by R. mucilaginosa in an in vitro test. Rapid colonization of the yeast in apple wounds was observed whether stored at 20 °C or 4 °C. In apples, the activities of peroxidase (POD) and polyphenoloxidase (PPO) were significantly induced and lipid peroxidation (malondialdehyde (MDA) content) was highly inhibited by R. mucilaginosa treatment compared with those of the control fruits. All these results indicated that R. mucilaginosa has great potential for development of commercial formulations to control postharvest pathogens on fruits. Its modes of action were based on competition for space and nutrients with pathogens, inducement of activities of defense-related enzymes such as POD, PPO and inhibition of lipid peroxidation (MDA content) of apples, so as to enhance the resistance and delay the ripening and senescence of apples.     

苯并噻二唑结合罗伦隐球酵母对桃果采后青霉病的控制

研究了拮抗酵母菌罗伦隐球酵母与植物诱导剂苯并噻二唑(BTH)结合使用控制桃果青霉病的效果。结果显示,罗伦隐球酵母与100μg/mL的BTH结合使用时,不仅其生防效力显著提高,还可以显著提高桃果的抗性相关酶活性,包括过氧化物酶(POD)和过氧化氢酶(CAT),并且抑制了丙二醛(MDA)含量的增加。因此,BTH与罗伦隐球酵母结合使用,集成了生物防治酵母和植物生长调节剂的生物双重活性,可能成为防治桃果采后病害的一个新途径。      

BABA处理对葡萄果实采后灰霉病的影响及机理

以‘巨峰’葡萄果实为实验材料,研究β-氨基丁酸（β-aminobutyric acid,BABA）处理对葡萄果实灰霉病、抗病相关酶活性和总酚含量的影响。葡萄果实先用75 mmol/L的BABA溶液处理后刺伤接种灰霉葡萄孢菌,然后转入25 ℃贮藏60 h。结果发现,BABA处理有效抑制了‘巨峰’葡萄果实的腐烂和病斑的扩展;同时BABA处理还诱导了果实中几丁质酶、β-1,3葡聚糖酶、苯丙氨酸解氨酶、4-香豆酸辅酶A连接酶和肉桂酸羟化酶等抗病相关酶活性以及总酚含量的提高。结果表明,BABA可诱导葡萄果实产生抗病性,从而减少灰霉病的发生。     

马尾松回用纤维品质衰变规律及其机理研究

通过对马尾松亚硫酸盐浆、TMP浆和GWP浆的回用实验,本文得出了回用纤维品质衰变的基本规律。根据著名的Page方程,从回用纤维中聚戊糖含量的变化和回用纤维长度分布的变化以及回用纤维纸页光散射系数变化等数据中推断出了影响回用纤维品质衰变的主要因素,并进一步探讨了这些因素影响回用纤维品质的机理。