Revisiting the Hydrogen Storage Behavior of the Na-O-H System

Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS) experiments of NaH-NaOH composites reveal two principal features: Firstly, an H₂ desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH) and hydridic hydrogen (in NaH) important in the dehydrogenation mechanism, but that also an intra-phase H^δ+… H^δ– interaction may be a crucial step in the desorption process.     

Tinea faciei starting at day two of life

Dermatophyte infections are exceedingly rare in neonates, possibly due to the thin stratum corneum and high sebum content of neonatal skin. Only a handful of cases of tinea faciei have been reported in neonates, with the majority of reports occuring in India. Here, we report what to our knowledge is the earliest reported presentation of tinea faciei in the United States. We also provide a brief literature review of other reported cases of tinea faciei in neonates less than 30 days of age.     

Differential effects of cannabis extracts and pure plant cannabinoids on hippocampal neurones and glia

We have shown previously that the plant cannabinoid cannabidiol (CBD) elevates intracellular calcium levels in both cultured hippocampal neurones and glia. Here, we investigated whether the main psychotropic constituent of cannabis, Δ⁹-tetrahydrocannabinol (THC) alone or in combination with other cannabis constituents can cause similar responses, and whether THC affects the responses induced by CBD. Our experiments were performed with 1 μM pure THC (pTHC), with 1 μM pure CBD (pCBD), with a high-THC, low CBD cannabis extract (eTHC), with a high-CBD, low THC cannabis extract (eCBD), with a mixture of eTHC and eCBD (THC:CBD = 1:1) or with corresponding ‘mock extracts’ that contained only pTHC and pCBD mixed in the same proportion as in eTHC, eCBD or the 1:1 mixture of eTHC and eCBD.     

全膝关节置换术后的骨溶解：胫骨盘表面的修饰及聚乙烯衬垫灭菌方法对其的影响术 后5至10年的报告

背景：从关节和胫骨假体聚乙烯衬垫后表面转移磨损碎屑，是全膝关节置换术后假体周围骨溶解的主要原因。全膝人工关节假体设计随时问而发生变化，例如对胫骨盘近端表面的粗糙度和聚乙烯衬垫的灭菌方法。我们假设胫骨盘表面抛光和采用空气中γ射线照射之外的其他方法对衬垫灭菌，可降低骨溶解的发生率。方法：从1987年至1998年，我们采用后十字韧带保留型的解剖型组配式全膝人工关节假体系列。对300名患者施行365例全膝关节置换术。术后5至10年，对这些患者的膝关节摄正、侧位X线片。由两位关节置换专家对X线片上的骨溶解状况进行单独评定（骨溶解的界定标准为假体周围存在边缘清晰的非线性松质骨丢失区）。结果：在粗糙表面的胫骨盘的242例膝关节中，使用空气中γ射线照射灭菌的衬垫固定，有34％（82例）骨溶解阳性。用惰性气体中γ射线照射或没有照射的衬垫与抛光表面连接的98例膝关节中，有9％（9例）骨溶解阳性。骨溶解与六项因素相关，这些因素为：一项与患者（男性）相关、一项与胫骨盘（近端表面抛光）相关、三项与聚乙烯衬垫（加工的原材料、灭菌方法及存放时间）相关及一项与手术技术（股骨假体与胫骨假体间的过伸）相关。结论：在这类假体设计中，胫骨盘近端表面采用抛光及衬垫采用更为先进的灭菌方法（不用空气中γ射线照射灭菌）能显著减少骨溶解的发生率，但不能避免骨溶解。     

Use of CO2 to move structures as an aid to percutaneous procedures

By injecting small amounts of CO2 through a needle, one can move bowel or bladder from the intended path of instruments during interventional procedures. The technique worked well in six of seven cases in the pelvis and retroperitoneum; it was not effective in the mediastinum or midabdomen (n = 6).     

Ultrastructural observations of organelle accumulation in the equine recurrent laryngeal nerve

Summary The left recurrent laryngeal nerves from five horses with sub-clinical neuropathy were examined by light and electron microscopy in a study designed to examine accumulation of axonal organelles at paranodal and internodal locations. Transverse sections of the nerve showed scattered fibres with split myelin sheaths and axonal accumulation of organelles. On longitudinal sections these collections were seen to result from an axonal outpouching in which dense lamellar bodies and mitochondria had accumulated. These paranodal collections, which could be found on both sides of the node, were often associated with infoldings of the terminal loops of myelin and with occasional paranodal demyelination. The fact that many of the organelles in the outpouches were lysosomal in nature was confirmed by their positive staining for cathepsin D activity. Longitudinal sections demonstrated a number of axons which were swollen over a long distance and which contained focal accumulations of similar organelles. In places, however, there was a clear separation between these organelles and the cytoskeletal proteins. In each case these swollen axons were surrounded by Schwann cell nuclei and their processes, forming well-ordered onion bulbs. The possibility that these two types of changes, i.e. the paranodal accumulations and the axonal swellings could result from a disturbance in axonal transport in this distal axonopathy is discussed.