Electric Conductivities, Currents And Energy Dissipation In The Polar Ionosphere

Thesis (Ph.D.) University of Alaska Fairbanks, 1983During the International Magnetospheric Study (IMS), magnetic records from the six IMS meridian chain stations were obtained on March 17, 18 and 19, 1978. The data set is one of the most comprehensive ever obtained. Furthermore, several advanced computer codes calculating ionospheric current distributions based on the ground magnetic data were recently introduced. Combining the data set and the computer code developed by Kamide et al. (1981), it is attempted to re-examine the longstanding uncertainties in the current distributions and the energy dissipation rates in the polar ionosphere during substorms. For this purpose, a conductivity model which can reflect substorm conditions on an instantaneous basis was obtained based on the empirical relations of the north-south component ((DELTA)H) of the magnetic disturbance field observed at College, with the Pedersen and Hall conductivities deduced from Chatanika radar observations. In addition, the relationship of the particle energy injection rate, estimated from the radar, to (DELTA)H is also established. Based on the conductivity model thus obtained and the computer code, the ionospheric current distributions of 5-minute time resolution are obtained. Several interesting features in the current distributions during each phase of substorm are discussed. Furthermore, a new ionospheric current model during a substorm is schematically suggested. The IMF effects on the current patterns are also discussed. For several events, the roles of the ionospheric Pedersen and Hall currents are examined separately. By constructing the hourly distribution map of the Joule heat production rate, the particle energy injection rate and their sum over the entire polar region, it is possible to estimate the global Joule heat production rate, the global particle energy injection rate and the sum of the two quantities. It is found that the three global quantities are related almost linearly to the AE and AL indices

Cellular aging is associated with increased ubiquitylation of histone H2B in yeast telomeric heterochromatin

a b s t r a c t Epigenetic changes in chromatin state are associated with aging. Notably, two histone modifications have recently been implicated in lifespan regulation, namely acetylation at H4 lysine 16 in yeast and methylation at H3 lysine 4 (H3K4) in nematodes. However, less is known about other histone modifications. Here, we report that cellular aging is associated with increased ubiquitylation of histone H2B in yeast telomeric heterochromatin. An increase in ubiquitylation at histone H2B lysine 123 and methylations at both H3K4 and H3 lysine 79 (H3K79) was observed at the telomere-proximal regions of replicatively aged cells, coincident with decreased Sir2 abundance. Moreover, deficiencies in the H2B ubiquitylase complex Rad6/Bre1 as well as the deubiquitylase Ubp10 reduced the lifespan by altering both H3K4 and H3K79 methylation and Sir2 recruitment. Thus, these results show that low levels of H2B ubiquitylation are a prerequisite for a normal lifespan and the trans-tail regulation of histone modifications regulates age-associated Sir2 recruitment through telomeric silencing

Comprehensive understanding of cathodic and anodic polarization effects on stability of nanoscale oxygen electrode for reversible solid oxide cells

Whereas solid oxide cells (SOCs), which perform dual functions of power generation (fuel-cell mode) and energy storage (electrolysis mode) with high efficiency at high temperatures, are considered a potent candidate for future energy management systems, it is yet far from their practical use due to the fact that the stable long-term operations have not been achieved. Particularly, degradations of oxygen-electrode in the both electrolysis and fuel-cell operations are considered as the most imminent issues that should be overcome. Unfortunately, even the origins and mechanisms of degradation in the oxygen-electrode have not been clearly established due to the difficulties in precise assessments of microstructural/compositional changes of porous electrode, which is a typical form in actual solid oxide cells, and due to the diversities in operating conditions, electrode structure and material, fabrication history, and so on. We simultaneously investigated the degradation phenomena in electrolysis and fuel-cell operations for 540h using identical two half cells composed of a geometrically well-defined, nanoscale La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) dense film with a thickness of ~ 70 nm on Ce0.9Gd0.1O2-δ electrolyte. Owing to the benefit of well-defined geometry of LSCF thin film, the microstructural/compositional changes in LSCF films were successfully analyzed in nanoscale, and the correlation between the components of electrochemical impedance and the major origins resulting in degradations was clarified. Furthermore, we suggest the most probable degradation mechanisms, and importantly, it is newly suggested that kinetic demixing/decomposition of LSCF, which is not readily observable in the typical porous-structured electrode, are highly probable to affect the both fuel-cell and electrolysis long-term degradations

The Obturator Guiding Technique in Percutaneous Endoscopic Lumbar Discectomy

In conventional percutaneous disc surgery, introducing instruments into disc space starts by inserting a guide needle into the triangular working zone. However, landing the guide needle tip on the annular window is a challenging step in endoscopic discectomy. Surgeons tend to repeat the needling procedure to reach an optimal position on the annular target. Obturator guiding technique is a modification of standard endoscopic lumbar discectomy, in which, obturator is used to access triangular working zone instead of a guide needle. Obturator guiding technique provides more vivid feedback and easy manipulation. This technique decreases the steps of inserting instruments and takes safer route from the peritoneum

Topical administration of EGF suppresses immune response and protects skin barrier in DNCB-induced atopic dermatitis in NC/Nga mice

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by a complex, heterogeneous pathogenesis including skin barrier dysfunction, immunology, and pruritus. Although epidermal growth factor (EGF) is essential for epithelial homeostasis and wound healing, the effect of EGF on AD remains to be explored. To develop a new therapy for AD, the anti-AD potential of EGF was investigated by inducing AD-like skin lesions in NC/Nga mice using 2,4-dinitrochlorobenzene (DNCB). EGF was administrated to NC/Nga mice to evaluate its therapeutic effect on DNCB-induced AD. EGF treatment improved dermatitis score, ear thickness, epidermal hyperplasia, serum total immunoglobulin E level, and transepidermal water loss in NC/Nga mice with DNCB-induced AD. In addition, levels of skin barrier-related proteins such as filaggrin, involucrin, loricrin, occludin, and zonula occludens-1 (ZO-1) were increased by EGF treatment. These beneficial effects of EGF on AD may be mediated by EGF regulation of Th1/Th2-mediated cytokines, mast cell hyperplasia, and protease activated receptor-2 (PAR-2) and thymic stromal lymphopoietin (TSLP), which are triggers of AD. Taken together, our findings suggest that EGF may potentially protect against AD lesional skin via regulation of skin barrier function and immune response

Reversible reddish skin color change in a patient with compressive radial neuropathy

Background The motor and sensory symptoms caused by compressive radial neuropathy are well-known, but the involvement of the autonomic nervous system or the dermatologic symptoms are less well known. We report an unusual case of compressive radial neuropathy with reversible reddish skin color change. Case presentation A 42-year-old man was referred for left wrist drop, finger drop and a tingling sensation over the lateral dorsum of the left hand. Based on clinical information, neurologic examinations and electrophysiologic studies, he was diagnosed with compressive radial neuropathy. In addition, a reddish skin color change was observed at the area of radial sensory distribution. After two weeks of observation without specific treatment, the skin color had recovered along with a marked improvement in weakness and aberrant sensation. Conclusions Compressive radial neuropathy with a reversible reddish skin color change is unusual and is considered to be due to vasomotor dysfunction of the radial autonomic nerve. Compressive radial neuropathy is presented with not only motor and sensory symptoms but also autonomic symptoms; therefore, careful examination and inspection are needed at diagnosis