•A novel CNFs based Cu/ZrO2 catalyst for CO2 hydrogenation to methanol was investigated.•The efficiency of the catalyst was influenced by Cu content.•Efficient CO2 conversion recorded at relatively ...low reaction temperature.•N2O chemisorptions and activity data revealed the dependency of methanol synthesis rate on Cu surface area.
A series of novel bimetallic copper/zirconia carbon nanofibers supported catalysts with different Cu contents (5–25 wt%) were synthesized via deposition precipitation method. The physicochemical characterization of the calcined catalysts was carried out by X-ray diffraction, inductively coupled plasma optical emission spectroscopy, N2 adsorption–desorption, N2O chemisorption, temperature programmed reduction, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy and temperature programmed CO2 desorption. Structure-reactivity correlation for catalytic hydrogenation of CO2 to methanol was discussed in details. Reaction studies revealed 15 wt% as optimum Cu concentration for CO2 conversion to methanol with CO2/H2 feed volume ratio of 1:3. Cu surface area was found to play a vital role in methanol synthesis rate. CO2 conversion was observed to be directly proportional to the number of total basic sites. A comparative study of this novel catalyst with the recently reported data revealed the better CO2 conversion at relatively low reaction temperature.
Photoreceptor replacement by transplantation is proposed as a treatment for blindness. Transplantation of healthy photoreceptor precursor cells into diseased murine eyes leads to the presence of ...functional photoreceptors within host retinae that express an array of donor-specific proteins. The resulting improvement in visual function was understood to be due to donor cells integrating within host retinae. Here, however, we show that while integration occurs the majority of donor-reporter-labelled cells in the host arises as a result of material transfer between donor and host photoreceptors. Material transfer does not involve permanent donor-host nuclear or cell-cell fusion, or the uptake of free protein or nucleic acid from the extracellular environment. Instead, RNA and/or protein are exchanged between donor and host cells in vivo. These data require a re-evaluation of the mechanisms underlying rescue by photoreceptor transplantation and raise the possibility of material transfer as a strategy for the treatment of retinal disorders.
•A comprehensive review of heterogeneous catalytic CO2 reduction to methanol.•Different reaction aspects of the title reaction has been elaborated in details.•The review covers the recent challenges ...and latest developments for the said reaction.
Catalytic reduction of carbon dioxide to methanol is an attractive option to reduce concentration of greenhouse gas and generation of renewable energy. Moreover, depletion of fossil fuel, global warming and steep hikes in the price of fuels are the key driving factor to investigate methanol synthesis by CO2 hydrogenation. In the last few decades, several investigations on catalytic CO2 hydrogenation to methanol have been reported in the literature. This article deals with a comprehensive review of all the recent studies conducted during the past decades. Furthermore, different aspects of the reaction system such as thermodynamic constrains, catalysts formulation, reactors aspects, reaction mechanism and influences of reaction conditions are discussed in detail. By now, such a discussion is still missing, and we intend to close this gap in this paper. The current scenario demonstrates the existence of immense prospects and opportunities to investigate further in this area.
Profound muscle weakness during and after critical illness is termed intensive care unit-acquired weakness (ICUAW).
To develop diagnostic recommendations for ICUAW.
A multidisciplinary expert ...committee generated diagnostic questions. A systematic review was performed, and recommendations were developed using the Grading, Recommendations, Assessment, Development, and Evaluation (GRADE) approach.
Severe sepsis, difficult ventilator liberation, and prolonged mechanical ventilation are associated with ICUAW. Physical rehabilitation improves outcomes in heterogeneous populations of ICU patients. Because it may not be feasible to provide universal physical rehabilitation, an alternative approach is to identify patients most likely to benefit. Patients with ICUAW may be such a group. Our review identified only one case series of patients with ICUAW who received physical therapy. When compared with a case series of patients with ICUAW who did not receive structured physical therapy, evidence suggested those who receive physical rehabilitation were more frequently discharged home rather than to a rehabilitative facility, although confidence intervals included no difference. Other interventions show promise, but fewer data proving patient benefit existed, thus precluding specific comment. Additionally, prior comorbidity was insufficiently defined to determine its influence on outcome, treatment response, or patient preferences for diagnostic efforts. We recommend controlled clinical trials in patients with ICUAW that compare physical rehabilitation with usual care and further research in understanding risk and patient preferences.
Research that identifies treatments that benefit patients with ICUAW is necessary to determine whether the benefits of diagnostic testing for ICUAW outweigh its burdens.
Neuromuscular dysfunction is prevalent in critically ill patients, is associated with worse short-term outcomes, and is a determinant of long-term disability in intensive care unit survivors. ...Diagnosis is made with the help of clinical, electrophysiological, and morphological observations; however, the lack of a consistent nomenclature remains a barrier to research. We propose a simple framework for diagnosing and classifying neuromuscular disorders acquired in critical illness.
Vanadium is listed on the United States Environment Protection Agency (USEPA) candidate contaminant list # 2 (CCL2), and regulatory guidelines for vanadium exist in some US states. The USEPA requires ...treatability studies before making regulatory decisions on CCL2 contaminants. Previous studies have examined vanadium adsorption onto some metal hydroxides but not onto commercially available adsorbents. This paper briefly summarizes known vanadium occurrence in North American groundwater and assesses vanadium removal by three commercially available metal oxide adsorbents with different mineralogies.
GTO (Dow) is TiO2 based and
E-33 (Seven Trents) and
GFH (US Filter) are iron based. Preliminary vanadate adsorption kinetics onto GFH, E-33 and GTO has been studied and the homogenous surface diffusion model (HSDM) is used to describe the adsorption kinetics data. The effects of pH, vanadium concentration, and volume/mass ratio are assessed. Vanadium adsorption decreases with increasing pH, with maximum adsorption capacities achieved in at pH 3–4. Results indicate that all adsorbents remove vanadium; GFH has the highest adsorption capacity, followed by GTO and E-33. Data are best fit with the Langmuir model rather than Freundlich isotherms. Both the sorption maxima (Xm) and binding energy constant (
b) follow the trend GFH>GTO>E-33. Naturally occurring vanadium is also removed from Arizona ground water in rapid small-scale column tests (RSSCTs). Metal oxide adsorption technologies currently used for arsenic removal may also remove vanadium but not always with the same effectiveness.
A series of novel carbon nanofibers (CNFs) supported bimetallic copper/zirconia catalysts are synthesized by deposition precipitation method and calcined at different temperatures. Calcined catalysts ...are characterized by various techniques like X-ray diffraction, N sub(2) adsorption-desorption, N sub(2)O chemisorption, high resolution transmission electron microscopy, temperature programmed reduction, X-ray photo-electron spectroscopy and temperature programmed desorption (CO sub(2) & NH sub(3)). The structure-activity correlation is discussed in details. The results demonstrate 450 degreesC as optimum calcination temperature for methanol synthesis rate with CO sub(2)/H sub(2) feed volume ratio of 1:3. CO sub(2) conversion is found to be directly proportional to copper metallic surface area (S sub(Cu)), while a linear relationship is observed between methanol synthesis rate and fraction of dispersed Cu.
Treatment and prevention of hyperglycemia has been advocated for subjects with sepsis. Glucose variability, rather than the glucose level, has also been shown to be an important factor associated ...with in-hospital mortality, in general, critically ill patients. Our objective was to determine the association between glucose variability and hospital mortality in septic patients and the expression of glucose variability that best reflects this risk.
Retrospective, single-center cohort study.
Academic, tertiary care hospital.
Adult subjects hospitalized for >1 day, with a diagnosis of sepsis were included.
None.
Glucose variability was calculated for all subjects as the average and standard deviation of glucose, the mean amplitude of glycemic excursions, and the glycemic lability index. Hospital mortality was the primary outcome variable. Logistic regression was used to determine the odds of hospital death in relation to measures of glucose variability after adjustment for important covariates.
Of the methods used to measure glucose variability, the glycemic lability index had the best discrimination for mortality (area under the curve = 0.67, p < 0.001). After adjustment for confounders, including the number of organ failures and the occurrence of hypoglycemia, there was a significant interaction between glycemic lability index and average glucose level, and the odds of hospital mortality. Higher glycemic lability index was not independently associated with mortality among subjects with average glucose levels above the median for the cohort. However, subjects with increased glycemic lability index, but lower average glucose values had almost five-fold increased odds of hospital mortality (odds ratio = 4.73, 95% confidence interval = 2.6-8.7) compared with those with lower glycemic lability index.
Glucose variability is independently associated with hospital mortality in septic patients. Strategies to reduce glucose variability should be studied to determine whether they improve the outcomes of septic patients.
Machine learning and deep learning algorithms are widely used in computer science domains. These algorithms are mostly used for classification and regression problems in almost every field of life. ...Semantic segmentation is an instantly growing research topic in the last few decades that refers to the association of each pixel in the image to the class it belongs. This paper illustrates the systematic survey of advanced research in the field of semantic segmentation till date. This study provides the brief knowledge about the latest proposed methods in the domain of semantic segmentation. The proposed study comprehends the concepts, techniques, tool, and results of different research frameworks proposed in the context of semantic segmentation. This study discusses the latest research papers in which machine learning and deep learning techniques are exploited for semantic segmentation and published between 2016 and 2021. The systematic literature review collected from seven different article libraries including ACM digital Library, Google Scholar, IEEE Xplore, Science Direct, Google Books, Refseek and Worldwide Science. For assuring the quality of the paper those papers are selected which have several citations on standardized platforms. Most of the studies used COCO, PASCAL, Cityscapes and CamVid dataset for training and validation of the machine learning and deep learning models. The results of the selected research articles are collected in the form of accuracy, mIoU value, F1 score, precision, and recall. In this study, we also conclude that most of the semantic segmentation studies use ResNet as the backbone of the architecture and none of the researchers used ensemble learning methods for semantic segmentation that is the loophole of the selected studies.
Background
Waiting lists for kidney transplantation continue to grow and live organ donation has become more important as the number of brain stem dead cadaveric organ donors continues to fall. The ...major disincentive to potential kidney donors is the pain and morbidity associated with open surgery.
Objectives
To identify the benefits and harms of using laparoscopic compared to open nephrectomy techniques to recover kidneys from live organ donors.
Search methods
We searched the online databases CENTRAL (in The Cochrane Library 2010, Issue 2), MEDLINE (January 1966 to January 2010) and EMBASE (January 1980 to January 2010) and handsearched textbooks and reference lists.
Selection criteria
Randomised controlled trials comparing laparoscopic donor nephrectomy (LDN) with open donor nephrectomy (ODN).
Data collection and analysis
Two review authors independently screened titles and s for eligibility, assessed study quality, and extracted data. We contacted study authors for additional information where necessary.
Main results
Six studies were identified that randomised 596 live kidney donors to either LDN or ODN arms. All studies were assessed as having low or unclear risk of bias for selection bias, allocation bias, incomplete outcome data and selective reporting bias. Four of six studies had high risk of bias for blinding. Various different combinations of techniques were used in each study, resulting in heterogeneity in the results. The conversion rate from LDN to ODN ranged from 1% to 1.8%. LDN was generally found to be associated with reduced analgesia use, shorter hospital stay, and faster return to normal physical functioning. The extracted kidney was exposed to longer warm ischaemia periods (2 to 17 minutes) with no associated short‐term consequences. ODN was associated with shorter duration of procedure. For those outcomes that could be meta‐analysed there were no significant differences between LDN or ODN for perioperative complications (RR 0.87, 95% CI 0.47 to 4.59), reoperations (RR 0.57, 95% CI 0.09 to 3.64), early graft loss (RR 0.31, 95% CI 0.06 to 1.48), delayed graft function (RR 1.09, 95% CI 0.52 to 2.30), acute rejection (RR 1.41, 95 % CI 0.87 to 2.27), ureteric complications (RR 1.51, 95% CI 0.69 to 3.31), kidney function at one year (SMD 0.15, 95% CI ‐0.11 to 0.41) or graft loss at one year (RR 0.76, 95% CI 0.15 to 3.85).
Authors' conclusions
LDN is associated with less pain compared with open surgery; however, there are equivalent numbers of complications and occurrences of perioperative events that require further intervention. Kidneys obtained using LDN procedures were exposed to longer warm ischaemia periods than ODN‐acquired grafts, although this has not been reported as being associated with short‐term consequences.
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