Solar photolysis of CH2I2, CH2ICl, and CH2IBr in water, saltwater, and seawater

Ultraviolet-visible absorption spectroscopy and purge-and-trap GC-MS were used to determine the rates and products of the photodissociation of low concentrations of CH2I2, CH2IBr, and CH2ICl in water, saltwater (0.5 M NaCl), and seawater in natural sunlight. Photoproducts of these reactions include iodide (I-) and, in salt- and seawater environments, CH2XCl (where X = Cl, Br, or I). Thus, CH2ICl was produced during CH2I2 photolysis (with a molar yield of 35 +/- 20%), CH2BrCl from CH2IBr photolysis, and CH2Cl2 from CH2ICl photolysis (in lower yields of 6-10%). Formation of these chlorine-atom-substituted products may be via direct reaction of Cl- with either (A) the isopolyhalomethane photoisomer or associated ion pair (e.g., CH2I+-I-) or (B) the initially produced CH2I. photofragment. Estimated quantum yields for photodissociation were 0.62 +/- 0.09, 0.17 +/- 0.03, and 0.26 +/- 0.06 for CH2I2, CH2IBr, and CH2ICl, respectively, in 0.5 M NaCl, with only small differences from these values in water and seawater. The much higher quantum yield of CH2I2 photolysis compared to CH2IBr and CH2ICl photolysis may be explained by the higher yield of the isodiiodomethane photoisomer of CH2I2, resulting in reduced geminate recombination of the initially produced radical photofragments back to the parent molecule. We use a radiative transfer model with measured absorption cross-sections in saltwater to calculate seasonal values of CH2I2, CH2IBr, and CH2ICl photodissociation in surface seawater at midlatitudes (50 degrees N) and show that a significant proportion of CH2ICl in surface seawater may arise from CH2I2 photodecomposition. We also suggest that surface seawater photolysis of CH2I2 over an 8 h period may contribute up to approximately 10% of the surface seawater I- levels, with implications for the increased deposition of O3 to the surface ocean.     

企业社会责任与CSC9000T

企业社会责任是指：企业在所从事的各种活动中,应当对所有利益相关者承担相应的责任,以求不仅在经济方面,更在社会、环境等领域获得可持续发展的能力。文章指出,企业社会责任运动自上世纪90年代从欧美兴起以来,其积极影响越来越明显,是人类文明与社会进步的表现。以跨国公司为代表的众多商业组织已开始规范其本身以及相应供贷商的社会行为准则,但目前尚没有全球统一的企业社会责任标准。因此,建立中国自己的企业社会责任管理体系意义重大,一方面有利于改善劳资关系,顺应国家“构建和谐社会”的历史潮流;另一方面,有助于中国制造业坚持“以人为本,走新型工业化道路”,实现可持续发展。CSC9000T——中国纺织企业社会责任管理体系正是在这种背景下应运而生的。     

Microbiological analysis of seed sprouts in Norway

As part of larger survey of microbial contamination of fruits and vegetables in Norway, four different sprouted seed products were analysed for bacterial and parasitic contaminants (n = 300 for bacterial analyses and n = from 17 to 171 for parasite analyses, depending on parasite). Escherichia coli O157, Salmonella, Listeria monocytogenes, Cyclospora oocysts, Ascaris eggs and other helminth parasites were not detected in any of the sprout samples. Thermotolerant coliform bacteria (TCB) were isolated from approximately 25% of the sprout samples, with the highest percentage of TCB positive samples in alfalfa sprouts. Most TCB were Enterobacter spp. and Klebsiella. E. coli was isolated from 8 of 62 TCB positive mung bean sprout samples. Cryptosporidium oocysts were detected in 8% of the sprout samples and Giardia cysts were detected in 2% of the samples. All the Cryptosporidium positive samples, and most of the Giardia positive samples, were mung bean sprouts. Parasite concentrations in positive samples were low (between 1 and 3 oocysts/cysts per 50 g sprouts). Sprout irrigation water was also analysed for microbial contaminants. E. coli O157 and L. monocytogenes were not detected. TCB were isolated from approximately 40% of the water samples. Salmonella reading was isolated from three samples of spent irrigation water on 3 consecutive days. Cryptosporidium and Giardia were also isolated from spent irrigation water. Additionally, eight samples of unsprouted mung bean seed were analysed for Cryptosporidium oocysts and Giardia cysts. One or both of these parasites were detected in six of the unsprouted seed samples at concentrations of between 1 and 5 oocysts/cysts per 100 g unsprouted seed. Whilst our results support spent irrigation water as the most suitable matrix for testing for bacteria, unsprouted seed is considered the more useful matrix for analysing for parasite contaminants.     

Short communication: Glucose infusion into early postpartum cows defines an upper physiological set point for blood glucose and causes rapid and reversible changes in blood hormones and metabolites

Low blood glucose concentrations after calving are associated with infertility in postpartum dairy cows perhaps because glucose is a master regulator of hormones and metabolites that control reproductive processes. The hypothesis was that low blood glucose postpartum is caused by inadequate glucose entry rate relative to whole-body demand as opposed to the alternative possibility that postpartum cows have a lower regulatory set point for blood glucose. Eight early postpartum (10 to 25 d) dairy cows (5 Holstein and 3 Guernsey) were jugular catheterized. During the first 24 h, cows were infused with physiological saline at 83.3 mL/h. After 24 h, the infusion solution was switched to 50% dextrose that was infused at a rate of 41.7 mL/h (total daily glucose dose = 500 g). On d 3 and d 4, the rate of glucose infusion was increased to 83.3 mL/h (daily dose = 1,000 g) and 125 mL/h (daily dose = 1,500 g), respectively. On d 5, physiological saline was infused at 83.3 mL/h. Blood was sampled hourly through a second jugular catheter (contralateral side) and analyzed for glucose, nonesterified fatty acids, β-hydroxybutyrate, insulin-like growth factor 1, and insulin. Blood glucose concentrations on d 1 (saline infusion) averaged 53.4 ± 1.7 mg/dL. Blood glucose concentrations increased on d 2 when cows were infused with 500 g/d and increased further on d 3 when cows were infused with 1,000 g of glucose/d. Increasing the infusion rate to 1,500 g/d on d 4 did not cause a further increase in blood glucose concentrations. Based on a segmented regression analysis, the upper physiological set point for blood glucose was 72.1 mg/dL. Both insulin and insulin-like growth factor 1 concentrations increased in response to glucose infusion and decreased when cows were infused with saline on d 5. Serum nonesterified fatty acids and β-hydroxybutyrate concentrations decreased in response to glucose infusion and rebounded upward on d 5 (saline infusion). In conclusion, early postpartum cows had circulating blood glucose concentrations that were well below the upper set point defined in this study (72.1 mg/dL). Infusing approximately 1,000 g of glucose daily increased blood glucose to the physiological set point and rapidly changed the hormonal and metabolic profile that typifies postpartum cows. The inability of the early postpartum cow to achieve an adequate entry rate for glucose relative to whole-body demand is a possible mechanism that links postpartum physiology and nutrition to reproduction in dairy cows.     

The application of metaphor, analogy, and conceptual models in computer systems

People using computer systems naturally relate what they are experiencing to what they already know. This general cognitive process can be classified into metaphoric, analogical, and modelling processes. Metaphor, a term applied often to today's computer systems, is the process of representing the computer system with objects and events from a noncomputer domain, such as the popular desktop metaphor. Analogy is a comparison between objects or events that serve the same purpose but have different representations. Models are representations of the abstract conceptual structure of a computer system. This paper outlines the differences between these three processes and applies them to the computer domain. Implications for computer systems design are also discussed.     

Gender in medical encounters: An analysis of physician and patient communication in a primary care setting.

The relation of physician and patient gender to verbal and nonverbal communication was examined in 100 routine medical visits. Female physicians conducted longer visits, made more positive statements, made more partnership statements, asked more questions, made more back-channel responses, and smiled and nodded more. Patients made more partnership statements and gave more medical information to female physicians. The combinations of female physician–female patient and female physician–male patient received special attention in planned contrasts. These combinations showed distinctive patterns of physician and patient behavior, especially in nonverbal communication. The relation of the results to gender differences in nonclinical settings, role strains in medical visits, and current trends in medical education are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Active damping of piezo-composite beams

The aim of the present study is to investigate the effects of piezoceramic materials on the active damping of vibrating piezo-composite beams. The active damping is obtained by using an actuator and a sensor piezoceramic layer acting in ‘closed-loop’. By transferring the accumulated voltage on the sensor layer to the piezoelectric actuator layer, the beam can actively damp-out its vibrations. An exact mathematical model, based on a first order shear deformation theory (FSDT) is developed and described. This model allows the investigation of piezo-composite beams with two actuation/sensing type mechanisms, extension and shear. The present study is confined to symmetric lay-up beams using continuous piezoelectric layers. Using the present model, both natural and damped vibrations are calculated. The effects of the feedback gain, G, and the beam length on the damped vibrations are investigated and presented.     

Children experiencing social difficulties: Sociometric neglect reconsidered.

Evaluates an oft-used sociometric procedure, the peer nomination technique. Examination of the data reveals support for the assumption that some rejected children are aggressive; however, the data concerning the behavioral characteristics of neglected children are equivocal. Data revealed that neglected children could not be distinguished from their average counterparts on any dependent measure. Rejected children were found to be more unpopular, aggressive, as well as withdrawn than the other sociometric groups. Results are discussed in terms of their implications for the use of sociometry to identify children "at risk" for social and emotional difficulties. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Beating Bias in the Directed Evolution of Proteins: Combining High‐Fidelity on‐Chip Solid‐Phase Gene Synthesis with Efficient Gene Assembly for Combinatorial Library Construction

Saturation mutagenesis (SM) constitutes a widely used technique in the directed evolution of selective enzymes as catalysts in organic chemistry and in the manipulation of metabolic paths and genomes, but the quality of the libraries is far from optimal due to the inherent amino acid bias. Herein, it is shown how this fundamental problem can be solved by applying high‐fidelity solid‐phase chemical gene synthesis on silicon chips followed by efficient gene assembly. Limonene epoxide hydrolase was chosen as the catalyst in the model desymmetrization of cyclohexene oxide with the stereoselective formation of (R,R)‐ and (S,S)‐cyclohexane‐1,2‐diol. A traditional combinatorial PCR‐based SM library, produced by simultaneous randomization at several residues by using a reduced amino acid alphabet, and the respective synthetic library were constructed and compared. Statistical analysis at the DNA level with massive sequencing demonstrates that, in the synthetic approach, 97 % of the theoretically possible DNA mutants are formed, whereas the traditional SM library contained only about 50 %. Screening at the protein level also showed the superiority of the synthetic library; many highly (R,R)‐ and (S,S)‐selective variants being discovered are not found in the traditional SM library. With the prices of synthetic genes decreasing, this approach may point the way to future directed evolution.     

Low‐temperature crystallization of La0.15Sr0.775TiO3 using ionic liquids

The n‐type thermoelectric oxide La_0.15Sr_0.775TiO₃ (LST) has been synthesized at 600°C using an ionic liquid method. The method uses the ionic liquid 1‐ethyl 3‐methylimidazolium acetate as the sole complexing agent: the lack of a second, carbon‐rich template decreases the quantity of reduced intermediate phases which form during heating. By suppressing these phases, greatly reduced temperatures can be used to crystallize the perovskite LST phase, on the nanoscale. These nanoparticles have the potential to be used to increase the figure of merit in n‐type thermoelectric oxide devices.