796 research outputs found
Simulating the mid-Pliocene Warm Period with the CCSM4 model
This paper describes the experimental design and model results from a 500 yr fully coupled Community Climate System, version 4, simulation of the mid-Pliocene Warm Period (mPWP) (ca. 3.3–3.0 Ma). We simulate the mPWP using the "alternate" protocol prescribed by the Pliocene Model Intercomparison Project (PlioMIP) for the AOGCM simulation (Experiment 2). Results from the CCSM4 mPWP simulation show a 1.9 °C increase in global mean annual temperature compared to the 1850 preindustrial control, with a polar amplification of ~3 times the global warming. Global precipitation increases slightly by 0.09 mm day−1 and the monsoon rainfall is enhanced, particularly in the Northern Hemisphere (NH). Areal sea ice extent decreases in both hemispheres but persists through the summers. The model simulates a relaxation of the zonal sea surface temperature (SST) gradient in the tropical Pacific, with the El Niño–Southern Oscillation (Niño3.4) ~20% weaker than the preindustrial and exhibiting extended periods of quiescence of up to 150 yr. The maximum Atlantic meridional overturning circulation and northward Atlantic oceanic heat transport are indistinguishable from the control. As compared to PRISM3, CCSM4 overestimates Southern Hemisphere (SH) sea surface temperatures, but underestimates NH warming, particularly in the North Atlantic, suggesting that an increase in northward ocean heat transport would bring CCSM4 SSTs into better alignment with proxy data
An Analysis of Pedestrian Waiting Time at Uncontrolled Crosswalks Using Discrete Choice Model
A study of pedestrians crossing behavior is conducted at an uncontrolled mid-block
crosswalk in Istanbul Turkey, to model the pedestrians waiting time, related to their behavior for
making the crossing decision. This article focused on the issues encountered in the modeling of
the operational behavior of pedestrians. The discrete choice framework is used because of its
capacity to deal with individuals’ choice behavior. Pedestrians waiting time is classified into
three levels, including low, medium, and high levels based on the level of service of pedestrians
waiting time. The pedestrians’ behavior prediction has been improved by analyzing, taking into
account three levels for pedestrian behavior
Standardized Outcomes in Nephrology-Transplantation: A Global Initiative to Develop a Core Outcome Set for Trials in Kidney Transplantation.
BACKGROUND: Although advances in treatment have dramatically improved short-term graft survival and acute rejection in kidney transplant recipients, long-term graft outcomes have not substantially improved. Transplant recipients also have a considerably increased risk of cancer, cardiovascular disease, diabetes, and infection, which all contribute to appreciable morbidity and premature mortality. Many trials in kidney transplantation are short-term, frequently use unvalidated surrogate endpoints, outcomes of uncertain relevance to patients and clinicians, and do not consistently measure and report key outcomes like death, graft loss, graft function, and adverse effects of therapy. This diminishes the value of trials in supporting treatment decisions that require individual-level multiple tradeoffs between graft survival and the risk of side effects, adverse events, and mortality. The Standardized Outcomes in Nephrology-Transplantation initiative aims to develop a core outcome set for trials in kidney transplantation that is based on the shared priorities of all stakeholders. METHODS: This will include a systematic review to identify outcomes reported in randomized trials, a Delphi survey with an international multistakeholder panel (patients, caregivers, clinicians, researchers, policy makers, members from industry) to develop a consensus-based prioritized list of outcome domains and a consensus workshop to review and finalize the core outcome set for trials in kidney transplantation. CONCLUSIONS: Developing and implementing a core outcome set to be reported, at a minimum, in all kidney transplantation trials will improve the transparency, quality, and relevance of research; to enable kidney transplant recipients and their clinicians to make better-informed treatment decisions for improved patient outcomes
The management of diabetic ketoacidosis in children
The object of this review is to provide the definitions, frequency, risk factors, pathophysiology, diagnostic considerations, and management recommendations for diabetic ketoacidosis (DKA) in children and adolescents, and to convey current knowledge of the causes of permanent disability or mortality from complications of DKA or its management, particularly the most common complication, cerebral edema (CE). DKA frequency at the time of diagnosis of pediatric diabetes is 10%–70%, varying with the availability of healthcare and the incidence of type 1 diabetes (T1D) in the community. Recurrent DKA rates are also dependent on medical services and socioeconomic circumstances. Management should be in centers with experience and where vital signs, neurologic status, and biochemistry can be monitored with sufficient frequency to prevent complications or, in the case of CE, to intervene rapidly with mannitol or hypertonic saline infusion. Fluid infusion should precede insulin administration (0.1 U/kg/h) by 1–2 hours; an initial bolus of 10–20 mL/kg 0.9% saline is followed by 0.45% saline calculated to supply maintenance and replace 5%–10% dehydration. Potassium (K) must be replaced early and sufficiently. Bicarbonate administration is contraindicated. The prevention of DKA at onset of diabetes requires an informed community and high index of suspicion; prevention of recurrent DKA, which is almost always due to insulin omission, necessitates a committed team effort
Twelve thousand years of dust: The Holocene global dust cycle constrained by natural archives
Mineral dust plays an important role in the climate system by interacting with radiation, clouds, and biogeochemical cycles. In addition, natural archives show that the dust cycle experienced variability in the past in response to global and local climate change. The compilation of the DIRTMAP paleodust datasets in the last two decades provided a target for paleoclimate models that include the dust cycle, following a time slice approach. We propose an innovative framework to organize a paleodust dataset that moves on from the positive experience of DIRTMAP and takes into account new scientific challenges, by providing a concise and accessible dataset of temporally resolved records of dust mass accumulation rates and particle grain-size distributions. We consider data from ice cores, marine sediments, loess/paleosol sequences, lake sediments, and peat bogs for this compilation, with a temporal focus on the Holocene period. This global compilation allows investigation of the potential, uncertainties and confidence level of dust mass accumulation rates reconstructions, and highlights the importance of dust particle size information for accurate and quantitative reconstructions of the dust cycle. After applying criteria that help to establish that the data considered represent changes in dust deposition, 43 paleodust records have been identified, with the highest density of dust deposition data occurring in the North Atlantic region. Although the temporal evolution of dust in the North Atlantic appears consistent across several cores and suggest that minimum dust fluxes are likely observed during the Early to mid-Holocene period (6000–8000 years ago), the magnitude of dust fluxes in these observations is not fully consistent, suggesting that more work needs to be done to synthesize datasets for the Holocene. Based on the data compilation, we used the Community Earth System Model to estimate the mass balance and variability of the global dust cycle during the Holocene, with dust load ranging from 17.1 to 20.5 Tg between 2000 and 10 000 years ago, and a minimum in the Early to Mid-Holocene (6000–8000 years ago)
Identification of Presurgical Risk Factors for the Development of Chronic Postsurgical Pain in Adults: A Comprehensive Umbrella Review
Beate C Sydora,1 Lindsay Jane Whelan,1,2 Benjamin Abelseth,2 Gurpreet Brar,3 Sumera Idris,3 Rachel Zhao,4 Ashley Jane Leonard,4 Brittany N Rosenbloom,5 Hance Clarke,6 Joel Katz,6,7 Sanjay Beesoon,1 Nivez Rasic2,8 1Department of Surgery Strategic Clinical Network, Alberta Health Services, Edmonton, AB, Canada; 2Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; 3Health Systems Knowledge and Evaluation, Alberta Health Services, Edmonton, AB, Canada; 4Knowledge Resource Service, Alberta Health Services, Edmonton, AB, Canada; 5Toronto Academic Pain Medicine Institute, Toronto, ON, Canada; 6Department of Anesthesia and Pain Management, Toronto General Hospital, UHN, Toronto, ON, Canada; 7Department of Psychology, York University, Toronto, ON, Canada; 8Department of Anesthesiology, Perioperative & Pain Medicine, University of Calgary, Calgary, AB, CanadaCorrespondence: Nivez Rasic, Department of Anesthesiology, Perioperative and Pain Medicine, University of Calgary, Medical Lead, Vi Riddell Pain & Rehabilitation Program, Acute Pain Lead, Alberta Pain Strategy, Alberta Children’s Hospital, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada, Tel +403-955-7810, Email [email protected] Sanjay Beesoon, Assistant Scientific Director, Surgery Strategic Clinical Network, Alberta Health Services, 02-048 South Tower, Seventh Street Plaza, 10030 107 St NW, Edmonton, AB, T5J 3E4, Canada, Tel +780-735-1682 ; +780-218-4786, Email [email protected]: Risk factors for the development of chronic postsurgical pain (CPSP) have been reported in primary studies and an increasing number of reviews. The objective of this umbrella review was to compile and understand the published presurgical risk factors associated with the development of CPSP for various surgery types.Methods: Six databases were searched from January 2000 to June 2023 to identify meta-analyses, scoping studies, and systematic reviews investigating presurgical CPSP predictors in adult patients. Articles were screened by title/abstract and subsequently by full text by two independent reviewers. The selected papers were appraised for their scientific quality and validity. Data were extracted and descriptively analyzed.Results: Of the 2344 retrieved articles, 36 reviews were selected for in-depth scrutiny. The number of primary studies in these reviews ranged from 4 to 317. The surgery types assessed were arthroplasty (n = 13), spine surgery (n = 8), breast surgery (n = 4), shoulder surgery (n = 2), thoracic surgery (n = 2), and carpal tunnel syndrome (n = 1). One review included a range of orthopedic surgeries; six reviews included a variety of surgeries. A total of 39 presurgical risk factors were identified, some of which shared the same defining tool. Risk factors were themed into six broad categories: psychological, pain-related, health-related, social/lifestyle-related, demographic, and genetic. The strength of evidence for risk factors was inconsistent across different reviews and, in some cases, conflicting. A consistently high level of evidence was found for preoperative pain, depression, anxiety, and pain catastrophizing.Conclusion: This umbrella review identified a large number of presurgical risk factors which have been suggested to be associated with the development of CPSP after various surgeries. The identification of presurgical risk factors is crucial for the development of screening tools to predict CPSP. Our findings will aid in designing screening tools to better identify patients at risk of developing CPSP and inform strategies for prevention and treatment.Plain Language Summary: Chronic postsurgical pain (CPSP) is pain experienced predominantly at the surgical site for longer than 3 months after a surgical procedure. Depending on surgery type, it can affect between 10 and 80% of people undergoing major surgeries, which may have negative effects such as a lower quality of life, disability, and persistent opioid use. Targeted identification and management of at risk patients in the presurgical phase may decrease the risk of CPSP. This umbrella review generated a list of potential risk factors for CPSP from evidence-based reviews of the current literature.Thirty-nine presurgical risk factors were identified in this review. Risk factors are divided into six broad categories: psychological, pain-related, health-related, demographic, genetic, and social/lifestyle-related. Although the strength of evidence for individual risk factors varied across reviews, risk factors in the psychological category consistently showed a strong impact on the development of CPSP.It is vital to understand which individuals are vulnerable and at risk for CPSP. The findings of this umbrella review will aid in designing screening tools to identify surgical candidates at risk. Some risk factors, such as genetics, cannot be altered. However, many identified risk factors are modifiable and may inform strategies for the prevention and treatment of CPSP using screening tools. Our findings may guide future research to consider an in-depth analysis of risk factor characterization to group modifiable presurgical risk factors. At risk patients will be offered psychological, physical, and pharmacological treatments accordingly to mitigate their risk of developing CPSP and ultimately improve patient outcomes in surgery.Keywords: chronic postsurgical pain, risk factors, predictors, umbrella review, surger
Nicotinamide Phosphoribosyltransferase/Visfatin Does Not Catalyze Nicotinamide Mononucleotide Formation in Blood Plasma
Nicotinamide (Nam) phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in mammalian NAD synthesis, catalyzing nicotinamide mononucleotide (NMN) formation from Nam and 5-phosphoribosyl 1-pyrophosphate (PRPP). NAMPT has also been described as an adipocytokine visfatin with a variety of actions, although physiological significance of this protein remains unclear. It has been proposed that possible actions of visfatin are mediated through the extracellular formation of NMN. However, we did not detect NMN in mouse blood plasma, even with a highly specific and sensitive liquid chromatography/tandem mass spectrometry. Furthermore, there is no or little ATP, the activator of NAMPT, in extracellular spaces. We thus questioned whether visfatin catalyzes the in situ formation of NMN under such extracellular milieus. To address this question, we here determined Km values for the substrates Nam and PRPP in the NAMPT reaction without or with ATP using a recombinant human enzyme and found that 1 mM ATP dramatically decreases Km values for the substrates, in particular PRPP to its intracellular concentration. Consistent with the kinetic data, only when ATP is present at millimolar levels, NAMPT efficiently catalyzed the NMN formation at the intracellular concentrations of the substrates. Much lower concentrations of Nam and almost the absence of PRPP and ATP in the blood plasma suggest that NAMPT should not efficiently catalyze its reaction under the extracellular milieu. Indeed, NAMPT did not form NMN in the blood plasma. From these kinetic analyses of the enzyme and quantitative determination of its substrates, activator, and product, we conclude that visfatin does not participate in NMN formation under the extracellular milieus. Together with the absence of NMN in the blood plasma, our conclusion does not support the concept of “NAMPT-mediated systemic NAD biosynthesis.” Our study would advance current understanding of visfatin physiology
Viewpoints of pedestrians with and without cognitive impairment on shared zones and zebra crossings
Background: Shared zones are characterised by an absence of traditional markers that segregate the road and footpath. Negotiation of a shared zone relies on an individual’s ability to perceive, assess and respond to environmental cues. This ability may be impacted by impairments in cognitive processing, which may lead to individuals experiencing increased anxiety when negotiating a shared zone. Method: Q method was used in order to identify and explore the viewpoints of pedestrians, with and without cognitive impairments as they pertain to shared zones. Results: Two viewpoints were revealed. Viewpoint one was defined by “confident users” while viewpoint two was defined by users who “know what [they] are doing but drivers might not”. Discussion: Overall, participants in the study would not avoid shared zones. Pedestrians with intellectual disability were, however, not well represented by either viewpoint, suggesting that shared zones may pose a potential barrier to participation for this group
The impact of preoperative anxiety and education level on long-term mortality after cardiac surgery
<p>Abstract</p> <p>Background</p> <p>Psychosocial factors have shown independent predictive value in the development of cardiovascular diseases. Although there is strong evidence to support the role of psychosocial factors in cardiovascular mortality, there is a scarcity of knowledge about how these factors are related. Therefore, we investigated the relationship between depression, anxiety, education, social isolation and mortality 7.5 years after cardiac surgery.</p> <p>Methods</p> <p>After informed consent, 180 patients undergoing cardiac surgery between July 2000 and May 2001 were prospectively enrolled and followed for ten years. During the follow-up period, the patients were contacted annually by mail. Anxiety (Spielberger State-Trait Anxiety Inventory, STAI-S/STAI-T), depression (Beck Depression Inventory, BDI) and the number and reason for rehospitalizations were assessed each year. Those patients who did not respond were contacted by telephone, and national registries were searched for deaths.</p> <p>Results</p> <p>During a median follow-up of 7.6 years (25<sup>th</sup> to 75<sup>th</sup> percentile, 7.4 to 8.1 years), the mortality rate was 23.6% (95% confidence interval [CI] 17.3-29.9; 42 deaths). In a Cox regression model, the risk factors associated with an increased risk of mortality were a higher EUROSCORE (points; Adjusted Hazard Ratio (AHR):1.30, 95%CI:1.07-1.58)), a higher preoperative STAI-T score (points; AHR:1.06, 95%CI 1.02-1.09), lower education level (school years; AHR:0.86, 95%CI:0.74-0.98), and the occurrence of major adverse cardiac and cerebral events during follow up (AHR:7.24, 95%CI:2.65-19.7). In the postdischarge model, the same risk factors remained.</p> <p>Conclusions</p> <p>Our results suggest that the assessment of psychosocial factors, particularly anxiety and education may help identify patients at an increased risk for long-term mortality after cardiac surgery.</p
Mapping and Functional Characterisation of a CTCF-Dependent Insulator Element at the 3′ Border of the Murine Scl Transcriptional Domain
The Scl gene encodes a transcription factor essential for haematopoietic development. Scl transcription is regulated by a panel of cis-elements spread over 55 kb with the most distal 3′ element being located downstream of the neighbouring gene Map17, which is co-regulated with Scl in haematopoietic cells. The Scl/Map17 domain is flanked upstream by the ubiquitously expressed Sil gene and downstream by a cluster of Cyp genes active in liver, but the mechanisms responsible for delineating the domain boundaries remain unclear. Here we report identification of a DNaseI hypersensitive site at the 3′ end of the Scl/Map17 domain and 45 kb downstream of the Scl transcription start site. This element is located at the boundary of active and inactive chromatin, does not function as a classical tissue-specific enhancer, binds CTCF and is both necessary and sufficient for insulator function in haematopoietic cells in vitro. Moreover, in a transgenic reporter assay, tissue-specific expression of the Scl promoter in brain was increased by incorporation of 350 bp flanking fragments from the +45 element. Our data suggests that the +45 region functions as a boundary element that separates the Scl/Map17 and Cyp transcriptional domains, and raise the possibility that this element may be useful for improving tissue-specific expression of transgenic constructs
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