A modular approach toward functionalized three-dimensional macromolecules: from synthetic concepts to practical applications

A new strategy for the preparation of functional, multiarm star polymers via nitroxide-mediated "living" radical polymerization has been explored. The generality of this approach to the synthesis of three-dimensional macromolecular architectures allows for the construction of nanoscopically defined materials from a wide range of different homo, block, and random copolymers combining both apolar and polar vinylic repeat units. Functional groups can also be included along the backbone or as peripheral/chain end groups, thereby modulating the reactivity and polarity of defined portions of the stars. This modular approach to the synthesis of three-dimensional macromolecules permits the application of these tailored materials as multifunctional hosts for hydrogen bonding, nanoparticle formation, and as scaffolds for catalytic groups. Examples of applications of the functional stars in catalysis include their use in a Heck-type coupling as well as an enantioselective addition reaction.     

温州地区维持性血液透析患者矿物质代谢紊乱情况调查

目的 了解温州地区维持性血液透析患者矿物质代谢紊乱情况及相关影响因素。方法 收集2013 年在温州地区长期维持性血液透析患者血钙、血磷、全段甲状旁腺激素（iPTH）的资料,并根据美国肾脏病协会指南（KDOQI）及中华医学会肾脏病学分会（CSN）制订的《慢性肾脏病矿物质和骨异常诊治指导》计算患者的血钙、血磷、iPTH 的达标率,并对相关影响因素进行分析。结果 共收集2 227 例2013 年在温州地区各家透析中心维持性血液透析患者的资料。按KDOQI 指南标准,患者血钙、血磷、iPTH 的达标率分别为44.90%、46.30%、27.64%,3 项均达标者占6.29%;按《慢性肾脏病矿物质和骨异常诊治指导》建议,患者血钙、血磷、iPTH 的达标率分别为57.66%、46.30%、61.14%,3 项均达标者占16.97%。此外,三级医院维持性血液透析患者的平均血磷水平为（1.67±0.51）mmol/L,血磷达标率49.10%,二级医院患者的平均血磷水平为（1.79±0.53）mmol/L,达标率为43.22%,三级医院维持性血液透析患者的血磷达标率情况优于二级医院。血白蛋白、含钙磷结合剂的使用及透析频率是影响血钙达标的独立相关因素。患者的性别、年龄、活性维生素D 的使用、透析龄及透析频率是影响血磷达标的独立相关因素。患者活性维生素D的使用是影响iPTH 达标的独立相关因素。结论 温州地区维持性血液透析患者矿物质代谢紊乱纠正情况与有关指南的要求仍然存在较大差距;患者性别、营养状态、透析频率、含钙磷结合剂的服用、活性维生素D 的使用等是影响维持性血液透析患者矿物质代谢紊乱纠正的主要相关因素。     

Fine-tuning molecular acoustic models: sensitivity of the predicted attenuation to the Lennard-Jones parameters

In a previous paper [Y. Dain and R. M. Lueptow, J. Acoust. Soc. Am. 109, 1955 (2001)], a model of acoustic attenuation due to vibration-translation and vibration-vibration relaxation in multiple polyatomic gas mixtures was developed. In this paper, the model is improved by treating binary molecular collisions via fully pairwise vibrational transition probabilities. The sensitivity of the model to small variations in the Lennard-Jones parameters--collision diameter (sigma) and potential depth (epsilon)--is investigated for nitrogen-water-methane mixtures. For a N2(98.97%)-H2O(338 ppm)-CH4(1%) test mixture, the transition probabilities and acoustic absorption curves are much more sensitive to sigma than they are to epsilon. Additionally, when the 1% methane is replaced by nitrogen, the resulting mixture [N2(99.97%)-H2O(338 ppm)] becomes considerably more sensitive to changes of sigma(water). The current model minimizes the underprediction of the acoustic absorption peak magnitudes reported by S. G. Ejakov et al. [J. Acoust. Soc. Am. 113, 1871 (2003)].     

The effect of methyl jasmonate and light irradiation treatments on the stilbenoid biosynthetic pathway in Vitis vinifera cell suspension cultures

Grape stilbenes are a well-known family of plant polyphenolics that have been confirmed to have many biological activities in relation to health benefits. In the present study, we investigated the effect of methyl jasmonate (MeJA) elicitor at four different concentrations (25, 50, 100 and 200 μM) in combination or not with high-level light irradiation (10,000 LUX) on a cell line obtained from the pulp of Vitis vinifera cv. Shahani. Our results showed that the stilbene synthesis pathway is inhibited by high-light conditions. A concentration of 50 μM MeJA was optimum for efficient production and high accumulation of total phenolics and total flavonoids as well as total stilbenoids. Furthermore, we showed that there is a significant negative correlation between the production of these metabolites and cell growth. These data provide valuable information for the future scale-up of cell cultures for the production of these very high value compounds in bioreactor system.     

粤航一号稻米及其亲本抗性淀粉含量的测定与比较

为确定航天品种功能稻米——粤航一号抗性淀粉含量,给临床观察膳食干预后果判断提供实验参考数据,并了解航天育种对该品种大米抗性淀粉含量的影响,用Goni测定方法测定了粤航一号、富硒粤航一号、长丝占、粳籼89 4种稻米的抗性淀粉含量。结果表明,粤航一号、富硒粤航一号、长丝占、粳籼89 4种稻米的抗性淀粉含量分别是(0.30±0.11)%、(0.47±0.37)%、(0.31±0.66)%、(0.36±0.62)%。可见粤航一号与亲本长丝占,及与富硒品种富硒粤航一号,和非航天品种优质大米粳籼89在抗性淀粉含量上无差异,航天育种对该品种稻米抗性淀粉生成遗传特征无影响。     

Catalytic C-H amination with aromatic amines

Aniline joins the club: A β-diketiminato copper(I) catalyst enables C-H amination of anilines employing low catalyst loadings to preclude oxidation to the diazene ArN=NAr. Electron-poor anilines are particularly resistant towards diazene formation and participate in the amination of strong and unactivated C-H bonds. N-alkyl anilines also take part in C-H amination.     

A model for the vertical sound speed and absorption profiles in Titan's atmosphere based on Cassini-Huygens data

Measurements of thermodynamic quantities in Titan's atmosphere during the descent of Huygens in 2005 are used to predict the vertical profiles for the speed and intrinsic attenuation (or absorption) of sound. The calculations are done using one author's previous model modified to accommodate non-ideal equations of state. The vertical temperature profile places the tropopause about 40 km above the surface. In the model, a binary nitrogen-methane composition is assumed for Titan's atmosphere, quantified by the methane fraction measured by the gas chromatograph/mass spectrometer (GCMS) onboard Huygens. To more accurately constrain the acoustic wave number, the variation of thermophysical properties (specific heats, viscosity, and thermal conductivity) with altitude is included via data extracted from the NIST Chemistry WebBook [URL webbook.nist.gov, National Institute of Standards and Technology Chemistry WebBook (Last accessed 10/20/2011)]. The predicted speed of sound profile fits well inside the spread of the data recorded by Huygens' active acoustic sensor. In the N(2)-dominated atmosphere, the sound waves have negligible relaxational dispersion and mostly classical (thermo-viscous) absorption. The cold and dense environment of Titan can sustain acoustic waves over large distances with relatively small transmission losses, as evidenced by the small absorption. A ray-tracing program is used to assess the bounds imposed by the zonal wind-measured by the Doppler Wind Experiment on Huygens-on long-range propagation.     

Lumped-element technique for the measurement of complex density.

A novel lumped-element technique is employed to measure the complex density of a gas in circular pores. The complex density expresses the geometry-dependent viscous coupling between the gas and the pore walls and is related to the thermoacoustic function f(mu), or equivalently, F(lambdaV). The acoustic impedance of a compliant region coupled to a pore (or pore-array) is measured and the impedance of the compliant region is subtracted to yield the impedance of the pore(s) alone, which is directly related to F(lambdaV). Pores of different lengths are measured in order to eliminate end effects. Working down to very low frequencies achieves a wide range of values for the ratio of the viscous penetration depth to the mean pore size. The results agree very well with analytical solutions for circular pores. The technique is also applied to two porous foam materials. Comparing the results to previous measurements of the complex compressibility, it is shown that two different shape factors (or equivalently, characteristic dimensions) are required to account for the data.