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.     

Predictive value and limitations of animal models for human transplantation: do we need more models for facial transplantation?

Animal models have traditionally provided the basis for preliminary investigation of new techniques prior to trials taking place in human subjects. The timing of when to proceed with human trials is difficult, as the accuracy of preclinical models can only be determined with hindsight. This review outlines the progression from transplantation in animal models to man. Now that many transplant procedures are well established, it is possible to assess the predictive value and limitations of animal models. These results are of great importance in the current debate about composite tissue allotransplantation (CTA) and in particular facial transplantation. This progression of CTA from animal models to man is outlined and compared with early renal, cardiac, and liver transplants. There is some evidence to suggest that animal models may have been misleading in CTA and that this has effectively delayed the transition to humans. The role for animal models in facial transplantation, which is currently making the step to clinical trials, is discussed.