576 research outputs found
Azimuthal correlation between the and planes in the semileptonic rest frame decay of a polarized top quark: An effect
The azimuthal correlation between the planes formed by the vectors
and in the
semileptonic rest frame decay of a polarized top quark belongs to a class of polarization observables involving the
top quark which vanish at the Born term level in the standard model. We
determine the next--to--leading order QCD corrections to the afore-mentioned
azimuthal correlation and compare the result to the corresponding contribution
of a non--standard--model right--chiral quark current.Comment: latex, 12 pages with 2 figures in the text, typos removed,comment and
references added, replaced with published versio
On the direction of transcription of cloned genes in Neurospora crassa.
On the direction of transcription of cloned genes in Neurospora crassa
Co-regulation of two tandem genes by one blue-light element in Neurospora crassa
Many genes of Neurospora crassa are regulated by blue light: al-1 (Schmidhauser et al. 1990 Mol. Cell. Biol. 10:5064-5070), al-2 (Lauter, Schmidhauser, Yanofsky, Russo unpublished), al-3 (Nelson et al. 1989 Mol. Cell. Biol. 9:1271-1276), bli-3, bli-4, bli-7, bli-13 (Sommer et al. 1989 NAR 17:5713-5723). For none of these genes are the blue light cis-regulatory sequences (blue-light elements, BE) known. Here we report the presence of such BE in front of bli-4
Osteoporosis and Sarcopenia Increase Frailty Syndrome in the Elderly
Musculoskeletal aging is a major public health interesting and strain due to the significant demographic modifications in the population, and it is linked to high risk of falls, loss of autonomy in elderly individuals and institutionalization with small health outcomes. Thus, this pathological status is related to high morbidity and health care rates. Bone mass and muscle mass and strength increase during late adolescence and early adulthood but start to reduce noticeably from the fifth decade of life and are closely linked. Bone and muscle tissues were increasingly recognized, as endocrine target organs and endocrine organs themselves, interacting through paracrine and endocrine signals. During growth, bone mineral content closely correlates with muscle mass, and several evidences suggest that osteoporosis and sarcopenia present common pathophysiological factors and show the correlation between low bone mineral density and sarcopenia in both men and women. Then, sarcopenia and osteoporosis, typical features of aging, are often associated with each other and with the frailty syndrome. In particular, sarcopenia and osteoporosis are major contributors to disability and frailty and the common denominators are age-related chronic inflammation, changes in body composition and hormonal imbalance. Frailty syndrome is characterized by a reduced response to stress, triggering the decline of the physiological functioning of the various systems. Frailty syndrome, typical of the older people, is frequently associated with a reduction in the quality of life and mobility. Falls often are the basis of reduced mobility and ability to perform the common functions of daily life and the increase in the number of institutionalizations. Moreover, the reduction of muscle mass, associated with altered muscle composition, fat and fibrous infiltration and alterations in innervations, and the increase in fat mass, have a synergistic effect on the increase in cardiovascular risk. The aim of this review is to analyze the pathophysiological mechanisms underlying the frailty syndrome and its association with sarcopenia and osteoporosis, and investigate possible intervention measures
Salt and Metal Tolerance Involves Formation of Guttation Droplets in Species of the Aspergillus versicolor Complex
Three strains of the Aspergillus versicolor complex were isolated from a salty marsh at a former uranium mining site in Thuringia, Germany. The strains from a metal-rich environment were not only highly salt tolerant (up to 20% NaCl), but at the same time could sustain elevated Cs and Sr (both up to 100 mM) concentrations as well as other (heavy) metals present in the environment. During growth experiments when screening for differential cell morphology, the occurrence of guttation droplets was observed, specifically when elevated Sr concentrations of 25 mM were present in the media. To analyze the potential of metal tolerance being promoted by these excretions, proteomics and metabolomics of guttation droplets were performed. Indeed, proteins involved in up-regulated metabolic activities as well as in stress responses were identified. The metabolome verified the presence of amino sugars, glucose homeostasis-regulating substances, abscisic acid and bioactive alkaloids, flavones and quinones
Mutation analysis of BRCA1 and BRCA2 genes in Iranian high risk breast cancer families
Background: Telomerase is a ribonucleoprotein enzyme that synthesises telomeres after cell
division and maintains chromosomal stability leading to cellular immortalization. Telomerase has
been associated with negative prognostic indicators in some studies. The present study aims to
detect any association between telomerase sub-units: hTERT and hTR and the prognostic
indicators including tumour's size and grade, nodal status and patient's age.
Methods: Tumour samples from 46 patients with primary invasive breast cancer and 3 patients
with benign tumours were collected. RT-PCR analysis was used for the detection of hTR, hTERT,
and PGM1 (as a housekeeping) genes expression.
Results: The expression of hTR and hTERT was found in 31(67.4%) and 38 (82.6%) samples
respectively. We observed a significant association between hTR gene expression and younger age
at diagnosis (p = 0.019) when comparing patients ≤ 40 years with those who are older than 40
years. None of the benign tumours expressed hTR gene. However, the expression of hTERT gene
was revealed in 2 samples.
No significant association between hTR and hTERT expression and tumour's grade, stage and nodal
status was seen.
Conclusion: The expression of hTR and hTERT seems to be independent of tumour's stage. hTR
expression probably plays a greater role in mammary tumourogenesis in younger women (≤ 40
years) and this may have therapeutic implications in the context of hTR targeting strategies
Chiral corrections to the vector and axial couplings of quarks and baryons
We calculate chiral corrections to the semileptonic vector and axial quark
coupling constants using a manifestly Lorentz covariant chiral quark approach
up to order O(p4) in the two- and tree-flavor picture. These couplings are then
used in the evaluation of the corresponding couplings which govern the
semileptonic transitions between octet baryon states. In the calculation of
baryon matrix elements we use a general ansatz for the spatial form of the
quark wave function, without referring to a specific realization of
hadronization and confinement of quarks in baryons. Matching the physical
amplitudes calculated within our approach to the model-independent predictions
of baryon chiral perturbation theory (ChPT) allows one to deduce the connection
between our parameters and those of baryon ChPT.Comment: 28 pages, 4 figure
- …