Phosphites and Hexafluoroacetone-Hexafluoroacetylacetones: a Comparison

Abstract

Selected acyclic and cyclic phosphites (RO)₂PX (1-5) were reacted with activated ketones (CF₃)₂CO (6) and Z-CF₃C(O)CH=C(OH)CF₃ (7a) / E-CF₃C(O)CH=C(OSiMe₃)CF₃ (7b) in order to study the influence of R and X on the product formation. A new type of insertion, a 1,4 group shift and cyclo-addition reactions yielding five membered rings and bicyclic fused systems were observed. In most cases phosphonates and their λ⁵[sgrave]⁵ P derivatives were obtained. The ketones in question can be considered versatile reactants in phosphorus chemistry.     

UiO-66-NH2 and Zeolite-Templated Carbon Composites for the Degradation and Adsorption of Nerve Agents

Composites of metal-organic frameworks and carbon materials have been suggested to be effective materials for the decomposition of chemical warfare agents. In this study, we synthesized UiO-66-NH₂/zeolite-templated carbon (ZTC) composites for the adsorption and decomposition of the nerve agents sarin and soman. UiO-66-NH₂/ZTC composites with good dispersion were prepared via a solvothermal method. Characterization studies showed that the composites had higher specific surface areas than pristine UiO-66-NH₂, with broad pore size distributions centered at 1–2 nm. Owing to their porous nature, the UiO-66-NH₂/ZTC composites could adsorb more water at 80% relative humidity. Among the UiO-66-NH₂/ZTC composites, U_0.8Z_0.2 showed the best degradation performance. Characterization and gas adsorption studies revealed that beta-ZTC in U_0.8Z_0.2 provided additional adsorption and degradation sites for nerve agents. Among the investigated materials, including the pristine materials, U_0.8Z_0.2 also exhibited the best protection performance against the nerve agents. These results demonstrate that U_0.8Z_0.2 has the optimal composition for exploiting the degradation performance of pristine UiO-66-NH₂ and the adsorption performance of pristine beta-ZTC.     

简论鲁迅小说《孔乙己》的三重意蕴

小说《孔乙己》具有深刻的思想性和高度的艺术性。在很短的篇幅中融入了鲁迅对人性、文化人自我定位以及生存本质的美学思考。论文论析了该小说在思想方面所具有的三重意蕴,体现为社会结构下的人性反思、人与文化关系的两难悖论、对生命＂原初痛苦＂的悲剧性揭示。     

探寻卡夫卡小说的社会意义——对《变形记》指引“苦痛”的思考

《变形记》作为卡夫卡短篇小说的代表作,以其真实的细节、象征、反讽等独特的艺术形式构筑出一个梦魇般的生活世界,具有独特的美学价值。然而其作为文学的功用不仅于此,它指引出现代人当下的生存困境及个体生命的苦痛,在唤醒我们对于自身主体意识关注的同时,引导我们以自省的姿态去改变令人不满的生存状态,探寻实现个体生命与社会和谐的途径,彰显着巨大的社会意义。     

Neurofilaments are intrinsic determinants of axonal caliber

Neurofilaments (NFs) are intrinsic determinants of axonal caliber in large-caliber myelinated nerve fibers. Axonal caliber is influenced by the number of NFs in the axon (axonal NF content) and the spacing between adjacent NFs (interfilament distance). Axonal NF content depends on the level of NF gene expression, the amount of NF protein entering the axon, and the velocity at which NF protein moves within the axon. In this review we discuss possible factors affecting both axonal NF content and interfilament distance; these include the ratio of NF subunits, the level of phosphorylation of these subunits, interactions with target cells, and interactions with ensheathing glial cells.     

Activity inAplysia buccal ganglia characterized by signal processing techniques

Summary Two procedures aimed at a synthetic, quantitative characterization of the integrative activity in a small system of nerve cells are proposed, and applications to the buccal ganglion of the molluskAplysia are described. Both methods are based on cross-correlation evaluation. The first method processes intracellular signals simultaneously recorded from pairs of neurones, and reveals and measures the occurrence of shared synaptic input. The second method processes extracellular multiunit signals recorded by two cuff electrodes placed around one nerve, and evaluates the impulse traffic, subdivided according to direction and speed of propagation. The outcome of both methods may be used to represent the state of the system, and may provide a basis to further studies on its dynamics. Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing and Related Phenomena?, Elba, 5–10 June 1994.     

基于BP神经网络的三维地质参数预测及立体图显示

基于现代神经网络数理统计新技术，提出一种简易可行的ＢＰ神经网络三维估值模型，以此可根据研究区域的已知资料对其未知点处的储层参数值进行高分辨率的预测；采用立体等值线图可视化技术来实现该模型估值的直观图形显示，充分揭示三维地质体某种特征参数的纵横向变化规律．最后成功地处理了Ｓ盆地中部气田马家沟组地层压力数据，结果表明，该法是一种有效的高分辨率估值技术，在油气藏描述中值得推广使用．     

Inhibitory Effect of Anisodamine on the Neuropathic Hyperalgesia Following Peripheral Nerve Injury(Ⅱ)

A peripheral neuropathy with hyperalgesia and allodynia was produced by loosely tying constrictive ligature around the left sciatic nerve of rats, i.v. injection of anisodamine 20mg/Kg abolished both neuropathic hyperalgesia responses to noxious radiant heat and ectopic discharges generated from the injured region of the nerve. Anisodanime applied either systemically or locally to the damaged area of the nerve not only ceased the spontaneous ectopic discharges recorded from A_β to C fibers but also blocked the afferent ectopic discharge elicited by K~+ channel blocker, noradrenaline, Ca~(2+) or antidromic stimulation of sciatic nerve proximal to the injured nerve area. The experiments indicated that anisodamine probably possessed a calcium channel blocker-like activity and produced selective block of the new channels in the injured area. It is suggested that anisodamine may be a candidate therapeutic agent in relieving hyperalgesia and allodynia following nerve injury.     

铅球教棍点拨法设计及其运用

在铅球技术教学中，教师或教练利用短棍使其手臂增长，在学生练习过程中，给予直接或间接的帮助，使其体会正确的肌肉用力，达到缩短教学时间、提高教学质量的目的。     

Recurrent Laryngeal Nerve Electrophysiologic Monitoring in Thyroid Surgery: The Standard of Care?

Reports in the literature suggest that the rate of transient and permanent vocal fold immobility (VFI) after thyroid surgery is 4% to 7% and 1% to 4%. The intraoperative use of nerve integrity monitors has been advocated to reduce the incidence of VFI during thyroid surgery. The purpose of this study was to compare postoperative VFI after unmonitored and monitored thyroid surgical procedures. The charts of 136 consecutive patients who underwent thyroid surgery from 1998 to 2003 were retrospectively surveyed. Fifty-four patients had total thyroidectomies, bringing the total recurrent laryngeal nerves (RLNs) dissected to 190. Three of 190 (1.6%) and 7 of 190 (3.7%) RLNs dissected had permanent and transient vocal fold dysfunction. Overall, 107 RLNs were unmonitored compared with 83 RLNs that were monitored. Unmonitored and monitored RLNs had a 4 of 83 (4.8%) versus 3 of 107 (2.8%) rate of transient VFI (P > 0.05). Unmonitored and monitored RLNs had a 1 of 107 (0.9%) versus 2 of 83 (2.4%) rate of permanent VFD (P > 0.05). Electrophysiologic RLN monitoring was not demonstrated in this study to reduce the incidence of transient or permanent VFI after thyroid surgery. Electrophysiologic RLN integrity does not always translate into clinical postoperative vocal fold mobility. Electrophysiologic RLN monitoring may support that the RLN was not severed in the patient with postoperative VFI.