326 research outputs found
Correlation Effects on Transport Through Few-Electrons Systems
We study lateral tunneling through a quantum box including electron-electron
interactions in the presence of a magnetic field which breaks single particle
degeneracies. The conductance at zero temperature as a function of the Fermi
energy in the leads consists of a set of peaks related to changing by one the
electron occupancy in the box. We find that the position and heights of the
peaks are controlled by many-body effects. We compute the conductance up to 8
electrons for several cases where correlation effects dominate. In the range of
intermediate fields spin selection rules quench some peaks. At low and high
fields the behavior of the conductance as a function of the number of electrons
is very different due to big changes in the many-body ground state
wavefunctions.Comment: 9 pages, 2 postscript figures, Latex 3.1
Система электропривода задвижки паропровода
INTRODUCTION: Encephalitis is a rare complication of primary varicella-zoster virus (VZV) infection in immunocompetent children. METHODS: The clinical and laboratory findings of two girls with VZV-related encephalitis are reported. RESULTS: Both children presented with focal epileptic seizures, corresponding to cortical/subcortical as well as white matter lesions. The first showed a typical vesicular skin rash. She was easily diagnosed and made a rapid recovery during acyclovir and steroid treatment. In the second girl, a preceding measles-mumps-rubella virus vaccination and the absence of skin vesicles were misleading with respect to the diagnosis, which was finally proven by IgG seroconversion and intrathecal synthesis of IgG antibodies to VZV. She developed left parieto-occipital tissue necrosis and recovered only transiently during initial acyclovir/steroid treatment. Eight weeks after onset, progressive white matter demyelination and the occurrence of erythema nodosum in the lower limbs necessitated a second 4-month course of oral steroids. The VZV PCR from cerebrospinal fluid was negative in both children. CONCLUSIONS: Primary VZV infection may cause severe encephalitis that may occur without skin vesicles and lead to a chronic course with systemic vasculitis. The coincidence of vaccination and neurologic diseases offers no proof per se of a causal relationship
Training community care workers to provide comprehensive TB⁄HIV⁄PMTCT integrated care in KwaZulu-Natal: Lessons learnt
To describe a participatory approach to implement and evaluate ways to integrate and traincommunity care workers (CCWs) to enhance collaborative TB⁄HIV⁄PMTCT activities, and home-basedHIV counseling and testing (HCT) at community level. The intervention study was conducted in Sisonke, a rural district of KwaZulu Natal, SouthAfrica. A baseline household (HH) survey was conducted in 11 villages. Six villages were randomlyselected into intervention and control clusters. Training was provided first to CCWs from the inter-vention cluster (IC) followed by the control cluster (CC). Routine monthly data from CCWs werecollected from March–December 2010. The data was subjected to bivariate tests
Studies of Acute Intestinal Obstruction. I. Different Types of Obstruction Produced under Local Anesthesia
11 p. Reprinted from: Archives of Internal Medicine, Vol. 34, No. 1, July 1924
Guanosine diphosphatase is required for protein and sphingolipid glycosylation in the Golgi lumen of Saccharomyces cerevisiae
Current models for nucleotide sugar use in the Golgi apparatus predict a critical role for the lumenal nucleoside diphosphatase. After transfer of sugars to endogenous macromolecular acceptors, the enzyme converts nucleoside diphosphates to nucleoside monophosphates which in turn exit the Golgi lumen in a coupled antiporter reaction, allowing entry of additional nucleotide sugar from the cytosol. To test this model, we cloned the gene for the S. cerevisiae guanosine diphosphatase and constructed a null mutation. This mutation should reduce the concentrations of GDP-mannose and GMP and increase the concentration of GDP in the Golgi lumen. The alterations should in turn decrease mannosylation of proteins and lipids in this compartment. In fact, we found a partial block in O- and N-glycosylation of proteins such as chitinase and carboxypeptidase Y and underglycosylation of invertase. In addition, mannosylinositolphosphorylceramide levels were drastically reduced
Cytochrome oxidase subunit VI of Trypanosoma brucei is imported without a cleaved presequence and is developmentally regulated at both RNA and protein levels
Mitochondrial respiration in the African trypanosome undergoes dramatic developmental stage regulation. This requires co-ordinated control of components encoded by both the nuclear genome and the kinetoplast, the unusual mitochondrial genome of these parasites. As a model for understanding the co-ordination of these genomes, we have examined the regulation and mitochondrial import of a nuclear-encoded component of the cytochrome oxidase complex, cytochrome oxidase subunit VI (COXVI). By generating transgenic trypanosomes expressing intact or mutant forms of this protein, we demonstrate that COXVI is not imported using a conventional cleaved presequence and show that sequences at the N-terminus of the protein are necessary for correct mitochondrial sorting. Analyses of endogenous and transgenic COXVI mRNA and protein expression in parasites undergoing developmental stage differentiation demonstrates a temporal order of control involving regulation in the abundance of, first, mRNA and then protein. This represents the first dissection of the regulation and import of a nuclear-encoded protein into the cytochrome oxidase complex in these organisms, which were among the earliest eukaryotes to possess a mitochondrion
In vivo human retinal imaging by ultrahigh-speed spectral domain optical coherence tomography
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