Породы песчаники – редкие материалы высокой крепости – уникальные фрикционные материалы

Розглядаються питання при підготовці до відпрацювання пологих вугільних пластів на великих глибинах в умовах шахти «Довжанська Капітальна» ТОВ "ДТЕК Свердловантрацит". Проведено дослідження вміщуючих підготовчу виробку порід. Запропоновано можливості проектування комплексного видобутку супутніх корисних компонентів при підготовці Антрацитівського пластів до видобутку.The questions in preparation for mining of shallow coal seams at great depths in the mine "Dolzhanskaya Capital" LLC "DTEK Sverdlovantratsit." Investigations of host rocks of underground working. Suggested the possibility of designing an integrated co-production of useful components in preparation Antratsitovskogo of flat seam to production

Acquisition time and reproducibility of continuous arterial spin-labeling perfusion imaging at 3 T

SUMMARY: Arterial spin-labeling (ASL) is a relatively new and noninvasive MR imaging technique, used to measure cerebral blood flow (CBF). Scanning time and reproducibility remain important issues in the clinical applicability of ASL. We expected both to benefit from higher field strengths. We describe that when performing ASL at 3T, 20 averages suffice to obtain steady and reproducible CBF values. Scanning time can be as short as 3 minutes. A rterial spin labeling (ASL) is a noninvasive MR imaging technique, used for visualization and quantification of cerebral perfusion. Cerebral blood flow (CBF) values measured by ASL are comparable with CBF values measured by conventional techniques (eg, positron-emission tomography or susceptibility-weighted MR imaging). ASL is based on magnetic labeling of arterial blood water protons, which are used as an endogenous tracer of flow. Magnetic inversion takes place in a plane proximal to the brain. The decay rate of the labeled spins is sufficiently long to visualize perfusion of brain vasculature and microvasculature. Perfusion images are obtained by subtraction of successively acquired labeled and nonlabeled control images. In general, 40 to 60 paired acquisitions are averaged to improve perfusion signal intensity. ASL sequences differ in the way magnetic labeling is applied and are commonly classified as continuous or pulsed ASL (CASL or PASL, respectively). In CASL, continuous adiabatic inversion of spins is applied. In PASL, labeling is performed at once over a wide spatial range. Pseudocontinuous ASL (pCASL) has been introduced recently and uses a series of discrete labeling pulses. 1-8 Despite its advantages, scanning time and reproducibility remain important issues in the clinical applicability of ASL. The use of higher-field strengths could overcome these issues because of increased signal-to-noise ratio, prolonged T1-weighted relaxation time of labeled blood, and better spatial and temporal resolution. Also, we hypothesized that acquisition-related reproducibility of ASL will improve at higher-field strengths, whereas physiology-related reproducibility will not change. Previous CASL reproducibility studies were performed at 1.5T with test-retest timeframes of at least 1 hour. Technique After approval of the local ethics committee and written informed consent from all volunteers, we scanned 10 volunteers (5 men; age range, 25-33 years) without known cerebrovascular disease during 3 different sessions within 3 weeks. Each session protocol consisted of 2 CASL sequences preceded by MR angiography. All scans were performed on a 3T Intera MR scanner with a transmit-receive head coil from the manufacturer (Philips Medical Systems, Best, the Netherlands). The 3D time-of-flight MR angiography was obtained to allow for careful planning of the labeling plane perpendicular to the distal ascending portion of the internal carotid and basilar arteries, 10 -20 mm below the circle of Willis. For the ASL sequences, we implemented the amplitude-modulated CASL approach described by Alsop and Detre 5 , without compromising clinical specific absorption rate levels. We used spin-echo single-shot echo-planar imaging. The imaging volume was positioned parallel to the labeling plane with its center 60 mm above the labeling plane. ASL parameters were TR, 4500 ms; TE, 32ms; flip angle, 90°; FOV, 210 ϫ 210; section thickness, 7 mm with 1-mm gap; matrix size, 64 ϫ 45 (reconstructed to 64 ϫ 64); 50 averages; labeling duration, 2.0 s; radiofrequency pulse amplitude, 3.5 T; gradient strength, 2.5 mT/m; modulation frequency, 250 Hz; and postlabeling delay, 1.2 to 2.2 s. FSL (FMRIB-Software-Library, Functional Magnetic Resonance Imaging of the Brain Centre, Department of Clinical Neurology, University of Oxford, Oxford, UK) was used for off-line data processing. f ϭ ⌬MR 1a 2␣M con {e ϪwR1a Ϫ e Ϫ(ϩW)R1a } in which f is CBF (mL/g/s), ␣ is the labeling efficiency at 3T (0.68), 7 is the blood-brain partition coefficient (0.98 mL/g), ⌬M is the difference between labeled image and control image intensity, R 1a is the longitudinal relaxation time of blood (0.67 s Ϫ1 ), M con is the average control image intensity, ⌻ is the labeling duration (2 s), and w is the postlabeling delay (1.2-2.2 s)

Medication screening using Beers and STOPP/START criteria for elderly patients: Association between potentially inappropriate medication and medication-related hospital admissions

OBJECTIVE To assess the risk of medication-related hospital admissions associated with inappropriate medication use applying the Beers and the STOPP/START criteria. There are multiple screening methods to detect and reduce potentially inappropriate medication [PIM] and prescribing omissions (PPOs). Whether this will result in less medication-related hospitalisations is unknown. DESIGN A nested case-control study was conducted with a subset of patients of the Hospital Admissions Related to Medication (HARM) study. METHODS Cases were defined as patients ≥65 years with a potentially preventable medication-related hospital admission. For each case one control was selected, matched on age and sex. The primary determinant was defined as the presence of one or more PlMs and/or PPOs according to the Beers 2012 and the STOPP/START criteria. The strength of the association between a PIM/PPO and a medication-related hospital admission was evaluated with multivariate logistic regression and expressed as odds ratios with 95% confidence intervals (Cl95). RESULTS PlMs and PPOs detected with the STOPP/START criteria are associated with medication-related hospital admissions [OR 3.47; CI95 1.70-7.09], while for the presence of PIMs according to the Beers 2012 criteria a non-significant trend was visible (ORadj 1.49; CI95 0.90-2.47). CONCLUSION Both the STOPP/START criteria and the Beers 2012 criteria can be used to identify older people at risk for medication-related problems. The choice which set of criteria should be used is more dependent on other factors (e.g. national guidelines, practical considerations) than on the association of each set with ADR-related hospital admission

Effect of increased convective clearance by on-line hemodiafiltration on all cause and cardiovascular mortality in chronic hemodialysis patients – the Dutch CONvective TRAnsport STudy (CONTRAST): rationale and design of a randomised controlled trial [ISRCTN38365125]

BACKGROUND: The high incidence of cardiovascular disease in patients with end stage renal disease (ESRD) is related to the accumulation of uremic toxins in the middle and large-middle molecular weight range. As online hemodiafiltration (HDF) removes these molecules more effectively than standard hemodialysis (HD), it has been suggested that online HDF improves survival and cardiovascular outcome. Thus far, no conclusive data of HDF on target organ damage and cardiovascular morbidity and mortality are available. Therefore, the CONvective TRAnsport STudy (CONTRAST) has been initiated. METHODS: CONTRAST is a Dutch multi-center randomised controlled trial. In this trial, approximately 800 chronic hemodialysis patients will be randomised between online HDF and low-flux HD, and followed for three years. The primary endpoint is all cause mortality. The main secondary outcome variables are fatal and non-fatal cardiovascular events. CONCLUSION: The study is designed to provide conclusive evidence whether online HDF leads to a lower mortality and less cardiovascular events as compared to standard HD

Pathways to ischemic neuronal cell death: are sex differences relevant?

We have known for some time that the epidemiology of human stroke is sexually dimorphic until late in life, well beyond the years of reproductive senescence and menopause. Now, a new concept is emerging: the mechanisms and outcome of cerebral ischemic injury are influenced strongly by biological sex as well as the availability of sex steroids to the brain. The principal mammalian estrogen (17 β estradiol or E2) is neuroprotective in many types of brain injury and has been the major focus of investigation over the past several decades. However, it is becoming increasingly clear that although hormones are a major contributor to sex-specific outcomes, they do not fully account for sex-specific responses to cerebral ischemia. The purpose of this review is to highlight recent studies in cell culture and animal models that suggest that genetic sex determines experimental stroke outcome and that divergent cell death pathways are activated after an ischemic insult. These sex differences need to be identified if we are to develop efficacious neuroprotective agents for use in stroke patients

Severe Pediatric COVID-19 and Multisystem Inflammatory Syndrome in Children from Wild-type to Population Immunity: A Prospective Multicenter Cohort Study with Real-time Reporting

Background: SARS-CoV-2 variant evolution and increasing immunity altered the impact of pediatric SARS-CoV-2 infection. Public health decision-making relies on accurate and timely reporting of clinical data. Methods: This international hospital-based multicenter, prospective cohort study with real-time reporting was active from March 2020 to December 2022. We evaluated longitudinal incident rates and risk factors for disease severity. Results: We included 564 hospitalized children with acute COVID-19 (n = 375) or multisystem inflammatory syndrome in children (n = 189) from the Netherlands, Curaçao and Surinam. In COVID-19, 134/375 patients (36%) needed supplemental oxygen therapy and 35 (9.3%) required intensive care treatment. Age above 12 years and preexisting pulmonary conditions were predictors for severe COVID-19. During omicron, hospitalized children had milder disease. During population immunity, the incidence rate of pediatric COVID-19 infection declined for older children but was stable for children below 1 year. The incidence rate of multisystem inflammatory syndrome in children was highest during the delta wave and has decreased rapidly since omicron emerged. Real-time reporting of our data impacted national pediatric SARS-CoV-2 vaccination- and booster-policies. Conclusions: Our data supports the notion that similar to adults, prior immunity protects against severe sequelae of SARS-CoV-2 infections in children. Real-time reporting of accurate and high-quality data is feasible and impacts clinical and public health decision-making. The reporting framework of our consortium is readily accessible for future SARS-CoV-2 waves and other emerging infections

Degradation of haloaromatic compounds

An ever increasing number of halogenated organic compounds has been produced by industry in the last few decades. These compounds are employed as biocides, for synthetic polymers, as solvents, and as synthetic intermediates. Production figures are often incomplete, and total production has frequently to be extrapolated from estimates for individual countries. Compounds of this type as a rule are highly persistent against biodegradation and belong, as "recalcitrant" chemicals, to the class of so-called xenobiotics. This term is used to characterise chemical substances which have no or limited structural analogy to natural compounds for which degradation pathways have evolved over billions of years. Xenobiotics frequently have some common features. e.g. high octanol/water partitioning coefficients and low water solubility which makes for a high accumulation ratio in the biosphere (bioaccumulation potential). Recalcitrant compounds therefore are found accumulated in mammals, especially in fat tissue, animal milk supplies and also in human milk. Highly sophisticated analytical techniques have been developed for the detection of organochlorines at the trace and ultratrace level

Screening for microorganisms producing D-malate from maleate.

More than 300 microorganisms were screened for their ability to convert maleate into D-malate as a result of the action of maleate hydratase. Accumulation of fumarate during incubation of permeabilized cells with maleate was shown to be indicative of one of the two enzymes known to transform maleate. The ratio in which fumarate and malate accumulated could be used to estimate the enantiomeric composition of the malate formed. Many strains (n = 128) were found to be capable of converting maleate to D-malate with an enantiomeric purity of more than 97%. Pseudomonas pseudoalcaligenes NCIMB 9867 was selected for more detailed studies. Although this strain was not able to grow on maleate, permeabilized cells were able to degrade maleate to undetectable levels, with a concomitant formation of D-malate. The D-malate was formed with an enantiomeric purity of more than 99.97%