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1.
cDNA selection was used to isolate coding sequences from cosmids mapping to the gene-rich telomeric region of human chromosome 21q. A novel cDNA, termed SMT3A, was isolated and mapped between the loci PFKL and D21S171, about 2.2 Mb proximal to the telomere. The predicted protein of 103 amino acids appears to be a homologue of the Saccharomyces cerevisiae SMT3 protein, whose gene was previously isolated as a suppressor of mutations in the MIF2 gene. The yeast MIF2 gene encodes an essential centromeric protein and shows homology to mammalian CENP-C, an integral component of active kinetochores. SMT3A was found to be highly homologous to two other recently isolated human genes, suggesting the presence of a new gene family. Homologous sequences were also found in protozoa, metazoa, and plants. Moreover, all predicted proteins show significant homology to ubiquitin. The proposed role of yeast SMT3 as centromeric protein and the strong evolutionary conservation of the SMT3A gene suggest an involvement of the encoded protein in the function and/or structure of the eukaryotic kinetochore.  相似文献   
2.
Three tests are routinely done to assess blood status of selenium in cattle: serum selenium, whole blood selenium, and glutathione peroxidase. The objective of this study was to compare the various analytical methods for determining blood selenium status in groups of mature cows and beef calves. Twenty to 30 blood samples per herd were collected from 8 beef herds in central Alberta and 1 dairy in Alberta herd twice a year from the spring of 1992 through the fall of 1995, and once from 185 spring calves in 2 beef herds in Saskatchewan. Serum and whole blood samples were submitted to 1 laboratory and whole blood samples were submitted to a 2nd laboratory. Samples for glutathione peroxidase determinations were submitted to a 3rd laboratory. Pearson's correlation coefficients and Cohen's kappa were calculated for each possible comparison among the different measures. The best agreement was observed between serum and whole blood analysis within Laboratory A. The remaining comparisons reflected poor agreement. Comparison of herd-level assessment resulted in better agreement than comparison of individual sample results among laboratories and procedures for all combinations tested. Serum selenium analysis was the only laboratory procedure for which external reference material was utilized. Serum selenium, whole blood selenium, and glutathione peroxidase measure different compartments of the blood selenium pool. The time frame of interest, supplementation practices, and the stability of recent dietary intake determine the optimum assessment method for individual animals or herds. Determination of the serum status or of blood selenium is more consistently measured at the herd-level than for individual samples.  相似文献   
3.
The most known effects of endogenous Cushing’s syndrome are the phenotypic changes and metabolic consequences. However, hypercortisolism can exert important effects on other endocrine axes. The hypothalamus–pituitary–thyroid axis activity can be impaired by the inappropriate cortisol secretion, which determinates the clinical and biochemical features of the “central hypothyroidism”. These findings have been confirmed by several clinical studies, which also showed that the cure of hypercortisolism can determine the recovery of normal hypothalamus–pituitary–thyroid axis activity. During active Cushing’s syndrome, the “immunological tolerance” guaranteed by the hypercortisolism can mask, in predisposed patients, the development of autoimmune thyroid diseases, which increases in prevalence after the resolution of hypercortisolism. However, the immunological mechanism is not the only factor that contributes to this phenomenon, which probably includes also deiodinase-impaired activity. Cushing’s syndrome can also have an indirect impact on thyroid function, considering that some drugs used for the medical control of hypercortisolism are associated with alterations in the thyroid function test. These considerations suggest the utility to check the thyroid function in Cushing’s syndrome patients, both during the active disease and after its remission.  相似文献   
4.
EGLE is a wide frequency band search- coil magnetometer designed and built at the Roma Tre University. It has been installed onboard the ISS by the Italian astronaut Roberto Vittori on April 25, 2005 within the LAZIO- EGLE experiment carried out during the ENEIDE Soyuz mission. The scope of the experiment is to test EGLE in space and to investigate geomagnetic field variations. The main applications of EGLE are the study of electromagnetic environment inside the ISS, the correlation of magnetic field data with particle fluxes detected by LAZIO particle detector, and the monitoring of ionospheric perturbations possibly caused by Earth seismic activity. Since continuous electromagnetic field measurements on board the ISS are important for diverse space applications, a magnetometer with a suitable design is requested. Appropriate solutions for these applications, which have been adopted by EGLE, are in particular the use of 1- Wire technology and the possibility to detect by means of a search- coil magnetometer a large portion of the ULF frequency band, usually measured by flux- gate probes. To investigate the topside ionosphere electromagnetic environment and stability of Van Allen radiation belts in relation with seismic and anthropogenic electromagnetic emissions, a specific satellite mission (the ESPERIA project) has been designed for the Italian Space Agency (ASI), and up to now a few instruments of its payload have been built and tested in space. One of them is exactly the EGLE search- coil magnetometer. The first magnetic observations performed by this instrument reveal to be promising and demand for a further and deeper analysis based on a longer time series of data.  相似文献   
5.
AIM: Renal functional reserve (RFR), resulting from an increase in glomerular filtration (GFR) after protein load, is a matter of debate. In kidney transplant recipients most studies have failed to show conclusive results, reporting either the absence, the reduction or the presence of renal reserve in normo-functioning kidneys. The aim of this study was to investigate RFR in kidney transplant patients as well as the possible hormonal vasoactive alterations underlying the reduction of renal reserve reported in some patients. PATIENTS AND METHODS: We studied 8 controls and 25 patients, the latter with no history of acute rejection for at least 12 months and GFR >50 ml/min. The 25 patients were divided into 2 groups based on the presence (10) or the absence (15) of RFR. RESULTS: Both the RFR group and the controls experienced a similar increase of GFR after oral protein load: 24.3 +/- 15.57% vs 24.4 +/- 10.8%. The group without RFR showed a paradoxical reduction of GFR after oral protein load: 13.3 +/- 13.2% (p <0.001). We analyzed the filtration fraction (FF) and observed that the group without RFR had higher values than the group with RFR and the controls: 0.35 +/- 0.11 vs 0.29 +/- 0.07 (p = 0.01) and vs 0.26 +/- 0.02 (p = 0.04). The hyperfiltration state observed in the group without RFR was sustained by a high level of thromboxane. The urine ratio TxB2/6ketoPgF1alpha was higher in the group without RFR than in the RFR group 0.78 +/- 0.2 vs 0.64 +/- 0.1 (p = 0.01). This ratio decreased only in the RFR group after a meat meal. In all the patients, changes of TxB2/6ketoPGF1alpha were inversely correlated to changes of GFR after a meat meal (r = -0.6, p = 0.01). CONCLUSIONS: In conclusion, these data demonstrate that kidney transplant recipients with good organ function can be grouped according to the presence of RFR. RFR appears to be inversely correlated with the TxB2/6ketoPGF1alpha ratio, and its decrease seems to be linked to the failure of thromboxane to decrease and prostacycline to increase after a meat meal.  相似文献   
6.
7.
Imaging through random aberrating media can be of interest not only in optics but also in microwaves or in acoustics. However, the holographic techniques applied in optics cannot be readily extended to microwaves without essential modifications. A different holographic method is here proposed which seems convenient at microwaves. The image is obtained by the product of the aberrated hologram with another compensating for the aberration. In the experiments two different procedures have been followed to perform the product of the two holograms, the optical and the electronic multiplication. The results obtained with the two procedures are shown, one of which allows the correction of time variant aberrations. With this technique there is no limitation in the off-set angles of the reference waves that could be also obtained by locally produced signals and no coherence is requested between the object and the compensating wave. The technique could be of interest, for instance, in plasma diagnostic and geophysical problems.  相似文献   
8.
In this paper a time–optimal current control algorithm with constant switching frequency for a STATCOM is presented. The method enables a fast transient response of the device limited only by its output voltage rating. The main idea behind the time–optimal current control is to find such control voltage that enables us to reach current reference values in a pre-determined minimal length of time. This control approach utilizes the mathematical model of the STATCOM and computes the exact required output to move the system state to the reference waveform. The algorithm is tested by means of simulations using the STATCOM mathematical model and a detailed model. The performance of the control algorithm is validated for reference current tracking and balanced and unbalanced network voltage sags. Simulations were carried out in PSCAD.  相似文献   
9.
Water-soluble functionalized carbon nanotubes (CNTs) have been prepared and further conjugated through a stable covalent bond with two peptidomimetics. The structural design of the covalently grafted peptidomimetics to the CNTs is based on their structural similarity with the metabolites of antagonist G of substance P. A variety of analytical spectroscopic methods, in combination with electron microscopy and thermal analysis, aided the structural and morphological characterization of the four newly synthesized peptidomimetic–CNT conjugates. It is demonstrated that the trypsin inhibitory effect of the peptidomimetic–CNT is enhanced as a result of the high-loading of peptidomimetics onto the skeleton of the modified water-soluble CNTs. Additionally, the peptidomimetic–functionalized CNT conjugates can be recovered and re-employed up to six biological evaluation cycles showing the same trypsin inhibitory activity. Such a nanosized system is extremely advantageous for the inhibition of inflammation or malignancy and could find potential future biological applications in the area of drug delivery systems.  相似文献   
10.
Microwave holography is an extension of the optical holography to the microwave field. In fact, by using a well-known characteristic of the holographic process, it is possible to record the hologram at frequencies very far from the optical region (microwave) and to reconstruct a visible image by laser light. This paper describes the experimental apparatus and the technique used for obtaining a satisfactory optical wave reconstruction from microwave holograms. The resolving power of the system which was experimentally tested, and visible images of microwave transparencies and of a back scattering object are given. As an alternative application of the microwave holography together with the optical wave reconstruction, in this paper, extension of holographic interferometry to the microwave region is suggested, and the visible image of a deformed object crossed by fringes due to microwave interference is also shown. This technique can find applications, for instance, in the mapping of the earth's deformations or in that of the tides. Different aspects of the microwave holographic interferometry have been also discussed.  相似文献   
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