胶原/生物活性玻璃/壳聚糖增强型复合支架

背景：生物活性玻璃/胶原复合材料具有优良的成骨活性和的生物学性能,然而其在人体环境中易降解而导致支架溃散、力学性能下降。 目的：构建具有良好力学性能、抗降解性能和骨修复特性的胶原/生物活性玻璃/壳聚糖增强型复合支架。 方法：以壳聚糖作为分散剂,将生物活性玻璃粉体预先在壳聚糖溶液中均匀分散,然后与胶原溶液混合,结合冷冻干燥法制备多孔胶原/生物活性玻璃/壳聚糖增强型复合骨修复支架。采用傅里叶变换红外光谱仪、场发射扫描电子显微镜、X射线衍射仪、动态生物力学试验机等对复合支架的结构和性能进行表征。 结果与结论：由于壳聚糖和生物活性玻璃粉体在微酸性环境下的电荷吸引,使在壳聚糖中预分散的生物活性玻璃颗粒在复合支架中分散更均匀;壳聚糖的引入大量增加了机体中的羟基和氨基,使分子间的相互作用增强,显著提高了材料的抗压模量和强度;壳聚糖和胶原在分子尺度的混合,使胶原分子被壳聚糖包裹,降低了胶原酶对胶原分子的酶切能力,显著提高了复合支架的抗胶原酶解性;壳聚糖分子使生物活性玻璃颗粒更均匀的包裹在大分子基相中,减少了生物活性玻璃颗粒的团聚和暴露,导致复合支架在模拟体液中的矿化活性略微降低。     

Gap junctions in the inner plexiform layer of the goldfish retina

Oblique thin sections of the goldfish inner plexiform layer (IPL) were examined to characterize the processes engaging in gap junctions. Omission of en bloc uranyl acetate staining enhanced the relative visibility of gap junctions, thus facilitating surveys. Three general categories were identified: (1) extensive gap junctions between large caliber amacrine cell dendrites presynaptic to ganglion cells and other amacrine cells in distal and proximal IPL; (2) moderate to small gap junctions between amacrine cell synaptic terminals or small amacrine cell-like processes of similar cytoplasmic appearance; and (3) gap junctions between the telodendria/terminals of bipolar cells. Most instances of gap junctions in the goldfish IPL seem to represent cases of homologous coupling. We have not found unambiguous cases of heterologous coupling as in the mammalian retina, nor have we yet found mixed synapses. Taken together with previous physiological and anatomical findings, homologous coupling occurs between pairs of rods, cones, horizontal cells, bipolar cells and amacrine cells in the goldfish retina, and this in turn implies that direct intercellular communication among like cell types is a common theme in retinal circuitry.     

第三次分配视角下网络公益众筹助力医疗救助的发力点及监管重点

网络公益众筹是多层次医疗保障体系的一项有益补充,可缓解因病致贫、因病返贫现象。推动健康中国建设,需要做好第二次分配与第三次分配、医疗救助与网络公益众筹有效衔接。本文在对医疗救助体系进行分析的基础上,厘清现有框架存在的短板和痛点,并提出网络公益众筹助力医疗救助的发展定位和发力点,以及政府对网络公益众筹的监管策略。     

Vanadium exposure-induced neurobehavioral alterations among Chinese workers

Vanadium-containing products are manufactured and widely used in the modern industry. Yet the neurobehavioral toxicity due to occupational exposure to vanadium remained elusive. This cross-sectional study was designed to examine the neurotoxic effects of occupational vanadium exposure. A total of 463 vanadium-exposed workers (exposed group) and 251 non-exposed workers (control group) were recruited from a Steel and Iron Group in Sichuan, China. A WHO-recommended neurobehavioral core test battery (NCTB) and event-related auditory evoked potentials test (P300) were used to assess the neurobehavioral functions of all study subjects. A general linear model was used to compare outcome scores between the two groups while controlling for possible confounders. The exposed group showed a statistically significant neurobehavioral alteration more than the control group in the NCTB tests. The exposed workers also exhibited an increased anger-hostility, depression-dejection and fatigue-inertia on the profile of mood states (p < 0.05). Performances in the simple reaction time, digit span, benton visual retention and pursuit aiming were also poorer among exposed workers as compared to unexposed control workers (p < 0.05). Some of these poor performances in tests were also significantly related to workers’ exposure duration. P300 latencies were longer in the exposed group than in the control (p < 0.05). Longer mean reaction times and more counting errors were also found in the exposed workers (p < 0.05). Given the findings of our study and the limitations of neurobehavioral workplace testing, we found evidence of altered neurobehavioral outcomes by occupational exposure to vanadium.     

小脑皮层神经回路及其功能作用(英文)

目的利用小脑的生理结构构造模拟小脑网络回路,研究小脑皮层不同神经细胞的电位发放、外界刺激对小脑皮层细胞的影响以及各类细胞电位发放模式等。方法与结果利用神经元的多房室模型和NEURON软件,研究不同输入刺激对蒲肯野细胞电位发放的影响。对颗粒细胞–高尔基细胞的反馈抑制回路对蒲肯野细胞的时间聚焦以及平行纤维–篮状/星状细胞局部抑制回路对蒲肯野细胞的空间聚焦现象进行了验证。运用施加运动学习的小脑网络模型研究兔子眨眼的条件反射现象,用模型的电位发放指标反映学习后兔子眨眼的实验现象。当刺激信号从攀状纤维输入时,通过精确放电时间依赖的突触可塑性学习,兔子眨眼的适应作用逐渐达到稳定状态。结论本文构造的小脑皮层网络真实可靠。模型的数值结果证实,小脑皮层经过精确放电时间依赖的突触可塑性学习后,输出信号稳定,可以执行时间聚焦和空间聚焦的功能。     

Leptomeningeal Myeloma As the Sole Manifestation of Relapse: An Unusual Presentation

We report a case of a 57-year-old African American male patient with standard risk (IIIA) IgA kappa multiple myeloma. This patient presented with neurologic complaints (manifesting as generalized muscle weakness and swallowing dysfunction associated with a poor cough reflex) 10 months after achieving a very good partial remission and without evidence of systemic progression. Examination of the cerebrospinal fluid revealed leptomeningeal involvement. Very little is known about the mechanisms of myelomatous spread to the leptomeninges, a very rare event, and the presentation of this case could raise awareness of this rare complication in those involved in caring for patients with multiple myeloma.     

吹扫捕集-GC—MS／SIM方法检测阿莫西林中的溶剂残留

目的：建立阿莫西林中甲基异丁基酮和醋酸丁酯2种挥发性有机溶剂的残留量测定方法。方法：采用用吹扫捕集浓缩仪和色谱-质谱联用（SIM）（P＆T—GC—MS／SIM）方法测定阿莫西林中甲基异丁基酮和醋酸丁酯2种挥发性有机溶剂的残留量。结果：吹扫管中2种溶剂量在0—3200ng范围内线性关系良好（r〉0．99）；吹扫管中2种溶剂量均为2400ng时，平行测定5次相对标准偏差分别为4．75％和0．66％；甲基异丁基酮和醋酸丁酯的检测限分别为2．9和4．8ng。结论：方法能满足粉状和液体药品中ng至μg级残留溶剂的测定。