9,739 research outputs found
A cell sizer network involving Cln3 and Far1 controls entrance into S phase in the mitotic cycle of budding yeast
Saccharomyces cerevisiae must reach a carbon source-modulated critical cell size, protein content per cell at the onset of DNA replication (Ps), in order to enter S phase. Cells grown in glucose are larger than cells grown in ethanol. Here, we show that an increased level of the cyclin-dependent inhibitor Far1 increases cell size, whereas far1Δ cells start bud emergence and DNA replication at a smaller size than wild type. Cln3Δ, far1Δ, and strains overexpressing Far1 do not delay budding during an ethanol glucose shift-up as wild type does. Together, these findings indicate that Cln3 has to overcome Far1 to trigger Cln–Cdc28 activation, which then turns on SBF- and MBF-dependent transcription. We show that a second threshold is required together with the Cln3/Far1 threshold for carbon source modulation of Ps. A new molecular network accounting for the setting of Ps is proposed
Proton pump inhibitors and serum magnesium levels in patients with Torsades de Pointes
Background: Torsades de pointes (TdP) is a life-threatening ventricular tachycardia occurring in long QT-syndrome patients. It usually develops when multiple QT-prolonging factors are concomitantly present, more frequently drugs and electrolyte imbalances. Since proton-pump inhibitors (PPIs)-associated hypomagnesemia is an increasingly recognized adverse event, PPIs were recently included in the list of drugs with conditional risk of TdP, despite only few cases of TdP in PPI users have been reported so far. Objectives: Aim of the present study is to evaluate whether PPI-induced hypomagnesemia actually has a significant clinical impact on the risk of TdP in the general population. Methods: Forty-eight unselected patients who experienced TdP were consecutively enrolled (2008-2017). Shortly after the first TdP episode, in those patients who did not receive magnesium sulfate and/or potassium or calcium replacement therapy, serum electrolytes were measured and their relationship with PPI usage analyzed. Results: Many patients (28/48, 58%) were under current PPI treatment when TdP occurred. Among TdP patients in whom serum electrolyte determinations were obtained before replacement therapy (27/48), those taking PPIs had significantly lower serum magnesium levels than those who did not. Hypomagnesemia occurred in ~40% of patients receiving PPIs (6/14), in all cases after an extended treatment (> 2 weeks). In patients taking PPIs the mean QT-prolonging risk factor number was significantly higher than in those who did not, a difference which was mainly driven by lower magnesium levels. Conclusions: In unselected TdP patients, PPI-induced hypomagnesemia was common and significantly contributed to their cumulative arrhythmic risk. By providing clinical support to current recommendations, our data confirm that more awareness is needed when a PPI is prescribed, specifically as regards the risk of life-threatening arrhythmias
HISTORICAL AND ARCHAEOSEISMIC STUDIES IN THE POLLINO AREA
Section 1. Reappraisal of the January 8, 1693 Pollino earthquake Section 2. Archaeoseismic field survey Section 3. Investigation of damaged speleothem
Biostimulants promoting growth of Vicia faba L. seedlings: inulin coated ZnO nanoparticles
In the present contribution, inulin coated ZnO nanoparticles (ZnO@inu NPs) were investigated for their potential application on crop production systems, by appraisal of their biostimulating effects on Vicia faba L (faba bean). Naked and coated ZnO NPs were synthesized according to purposely implemented eco-friendly protocols and characterized with multiple techniques to determine their crystallographic phase, average particle size, and degree of coating. Faba beans were grown in culture medium supplemented with NPs at 50 or 100 mg kg−1, using ZnO NPs alone, inulin alone, a mixture of the two, or ZnO@inu NPs. Seed germination rate and biometric evaluations on seedlings were carried out, together with Zn localization in the plant tissues. cellular and molecular effects were ascertained by analyses of photosynthetic pigments, cytotoxicity, genotoxicity, viability, induction of oxidative stress and tissue damage, antioxidant response, and modulation of gene expression. these combined studies indicated a potential role of ZnO@inu NPs in promoting growth and development of V. faba seedlings, acting at a post-germinative phase, probably by stimulating the stem cell mitosis. Finally, inulin as a coating agent for the ZnO NPs favored the bioavailability and adsorption of the nanomaterials into the plant tissues, without altering their bioactivity but mitigating any adverse side effect. Graphical Abstract: [Figure not available: see fulltext.]
Recent advances in the development of magnetically recoverable metal nanoparticle catalysts
The aim of this Account is to provide an overview of our current research activities on the design and modification of superparamagnetic nanomaterials for application in the field of magnetic separation and catalysis. First, an introduction of magnetism and magnetic separation is done. Then, the synthetic strategies that have been developed for generating superparamagnetic nanoparticles spherically coated by silica and other oxides, with a focus on well characterized systems prepared by methods that generate samples of high quality and easy to scale-up, are discussed. A set of magnetically recoverable catalysts prepared in our research group by the unique combination of superparamagnetic supports and metal nanoparticles is highlighted. This Account is concluded with personal remarks and perspectives on this research field
Bone demineralization and vertebral fractures in endogenous cortisol excess: role of disease etiology and gonadal status
INTRODUCTION: The effects of endogenous cortisol (F) excess on bone mass and vertebral fractures have still not been thoroughly investigated. The aim of this cross-sectional case-control study was to investigate factors influencing bone demineralization and vertebral fractures in different conditions of F excess, i.e. Cushing's disease and adrenal and ectopic Cushing's syndrome. MATERIALS AND METHODS: Eighty consecutive patients and 80 controls were prospectively enrolled: 37 patients (21 females) with pituitary ACTH-secreting adenoma, 18 (14 females) with adrenocortical adenoma, 15 (11 females) with adrenal carcinoma of mixed secretion, and 10 (three females) with ectopic ACTH secretion. The groups had similar age. At diagnosis, bone mineral density (BMD) was determined by the dual-energy x-ray absorptiometry technique at the lumbar spine (L1-L4) and femoral neck; vertebral fractures were investigated by standard spinal radiographs. RESULTS: When comparing the groups with different etiology of F excess, the patients with ectopic ACTH secretion had higher F and lower BMD values than the other subgroups. Morning F (P = 0.03) and testosterone levels (P = 0.04) correlated with lumbar BMD. Vertebral fractures were found in 61 (76%) of the patients, were multiple in 52 (85%) of the cases, and clinically evident in 32 (52%). Only multiple fractures were more frequent in patients with ectopic ACTH hypersecretion (P < 0.05). Lumbar spine BMD was the best predictor of vertebral fractures (P < 0.01). Surprisingly, amenorrheic and eumenorrheic women had similar BMD values and fracture prevalence. CONCLUSION: A high prevalence (76%) of vertebral fracture was revealed, regardless of the etiology of the patients' hypercortisolism. The harmful effects of F excess at the spine were partly counterbalanced by the increased androgen production but were not affected by gonadal status in women
A Generalized Q-operator for U_q(\hat(sl_2)) Vertex Models
In this paper, we construct a Q-operator as a trace of a representation of
the universal R-matrix of over an infinite-dimensional
auxiliary space. This auxiliary space is a four-parameter generalization of the
q-oscillator representations used previously. We derive generalized T-Q
relations in which 3 of these parameters shift. After a suitable restriction of
parameters, we give an explicit expression for the Q-operator of the 6-vertex
model and show the connection with Baxter's expression for the central block of
his corresponding operator.Comment: 22 pages, Latex2e. This replacement is a revised version that
includes a simple explicit expression for the Q matrix for the 6-vertex mode
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