919 research outputs found
Diet quality, liveweight change and responses to N supplements by cattle grazing Astrebla spp. (Mitchell grass) pastures in the semi-arid tropics in north-western Queensland, Australia
Experiments during 4 years examined the diets selected, growth, and responses to N supplements by Bos indicus-cross steers grazing summer-rainfall semi-arid C4 Astrebla spp. (Mitchell grass) rangelands at a site in north-western Queensland, Australia. Paddock groups of steers were not supplemented (T-NIL), or were fed a non-protein N (T-NPN) or a cottonseed meal (T-CSM) supplement. In Experiment 1, young and older steers were measured during the late dry season (LDS) and the rainy season (RS), while steers in Experiments 2–4 were measured through the annual cycle. Because of severe drought the measurements during Experiment 3 annual cycle were limited to T-NIL steers. Pasture availability and species composition were measured twice annually. Diet was measured at 1–2 week intervals using near infrared spectroscopy of faeces (F.NIRS). Annual rainfalls (1 July–30 June) were 42–68% of the long-term average (471 mm), and the seasonal break ranged from 17 December to 3 March. There was wide variation in pasture, diet (crude protein (CP), DM digestibility (DMD), the CP to metabolisable energy (CP/ME) ratio) and steer liveweight change (LWC) within and between annual cycles. High diet quality and steer liveweight (LW) gain during the RS declined progressively through the transition season (TS) and early dry season (EDS), and often the first part of the LDS. Steers commenced losing LW as the LDS progressed. In Experiments 1 and 2 where forbs comprised ≤15 g/kg of the pasture sward, steers selected strongly for forbs so that they comprised 117–236 g/kg of the diet. However, in Experiments 3 and 4 where forbs comprised substantial proportions of the pasture (173–397 g/kg), there were comparable proportions in the diet (300–396 g/kg). With appropriate stocking rates the annual steer LW gains were acceptable (121–220 kg) despite the low rainfall. The N supplements had no effect on steer LW during the TS and the EDS, but usually reduced steer LW loss by 20–30 kg during the LDS. Thus during low rainfall years in Mitchell grass pastures there were substantial LW responses by steers to N supplements towards the end of the dry season when the diet contained c. <58 g CP/kg or c. <7.0 g CP/MJ ME
Interactive molecular dynamics in virtual reality for accurate flexible protein-ligand docking
Simulating drug binding and unbinding is a challenge, as the rugged energy
landscapes that separate bound and unbound states require extensive sampling
that consumes significant computational resources. Here, we describe the use of
interactive molecular dynamics in virtual reality (iMD-VR) as an accurate
low-cost strategy for flexible protein-ligand docking. We outline an
experimental protocol which enables expert iMD-VR users to guide ligands into
and out of the binding pockets of trypsin, neuraminidase, and HIV-1 protease,
and recreate their respective crystallographic protein-ligand binding poses
within 5 - 10 minutes. Following a brief training phase, our studies shown that
iMD-VR novices were able to generate unbinding and rebinding pathways on
similar timescales as iMD-VR experts, with the majority able to recover binding
poses within 2.15 Angstrom RMSD of the crystallographic binding pose. These
results indicate that iMD-VR affords sufficient control for users to carry out
the detailed atomic manipulations required to dock flexible ligands into
dynamic enzyme active sites and recover crystallographic poses, offering an
interesting new approach for simulating drug docking and generating binding
hypotheses.Comment: PLOS ON
Geometry of the Grosse-Wulkenhaar Model
We define a two-dimensional noncommutative space as a limit of finite-matrix
spaces which have space-time dimension three. We show that on such space the
Grosse-Wulkenhaar (renormalizable) action has natural interpretation as the
action for the scalar field coupled to the curvature. We also discuss a natural
generalization to four dimensions.Comment: 16 pages, version accepted in JHE
Following the banking cycle of umbilical cord blood in India: the disparity between prebanking persuasion and post-banking utilization
To address critique of the rare uptake of umbilical cord blood (UCB) in private banks, hybrid-banking models would combine the advantages of ‘public UCB banking’ and private UCB banking by responding to both market forces and public needs. We question both by following the cycle of UCB banking in India: the circulation and stagnation of UCB as waste, gift, biological insurance, enclaved good, source of saving lives, and commodity through various practices of public, private and hybrid UCB banking. Making the journey from ‘recruitment’, ‘collection’ and ‘banking’ to ‘research’ and ‘therapy’ allowed us to identify concerns about the transparency of this cycle. Drawing on archival research and fieldwork interviews with different stakeholders in UCB banks in India, this article shows how private/hybrid cord blood banks are competing for their market share and its implication for the circulation of UCB: speculation, stagnation and opacity
Predictors of Successful Decannulation Using a Tracheostomy Retainer in Patients with Prolonged Weaning and Persisting Respiratory Failure
Background: For percutaneously tracheostomized patients with prolonged weaning and persisting respiratory failure, the adequate time point for safe decannulation and switch to noninvasive ventilation is an important clinical issue. Objectives: We aimed to evaluate the usefulness of a tracheostomy retainer (TR) and the predictors of successful decannulation. Methods: We studied 166 of 384 patients with prolonged weaning in whom a TR was inserted into a tracheostoma. Patients were analyzed with regard to successful decannulation and characterized by blood gas values, the duration of previous spontaneous breathing, Simplified Acute Physiology Score (SAPS) and laboratory parameters. Results: In 47 patients (28.3%) recannulation was necessary, mostly due to respiratory decompensation and aspiration. Overall, 80.6% of the patients could be liberated from a tracheostomy with the help of a TR. The need for recannulation was associated with a shorter duration of spontaneous breathing within the last 24/48 h (p < 0.01 each), lower arterial oxygen tension (p = 0.025), greater age (p = 0.025), and a higher creatinine level (p = 0.003) and SAPS (p < 0.001). The risk for recannulation was 9.5% when patients breathed spontaneously for 19-24 h within the 24 h prior to decannulation, but 75.0% when patients breathed for only 0-6 h without ventilatory support (p < 0.001). According to ROC analysis, the SAPS best predicted successful decannulation {[}AUC 0.725 (95% CI: 0.634-0.815), p < 0.001]. Recannulated patients had longer durations of intubation (p = 0.046), tracheostomy (p = 0.003) and hospital stay (p < 0.001). Conclusion: In percutaneously tracheostomized patients with prolonged weaning, the use of a TR seems to facilitate and improve the weaning process considerably. The duration of spontaneous breathing prior to decannulation, age and oxygenation describe the risk for recannulation in these patients. Copyright (c) 2012 S. Karger AG, Base
The failure of suicide prevention in primary care: family and GP perspectives - a qualitative study
Background Although Primary care is crucial for suicide prevention, clinicians tend to report completed suicides in their care as non-preventable. We aimed to examine systemic inadequacies in suicide prevention from the perspectives of bereaved family members and GPs.Methods Qualitative study of 72 relatives or close friends bereaved by suicide and 19 General Practitioners who have experienced the suicide of patients.Results Relatives highlight failures in detecting symptoms and behavioral changes and the inability of GPs to understand the needs of patients and their social contexts. A perceived overreliance on anti-depressant treatment is a major source of criticism by family members. GPs tend to lack confidence in the recognition and management of suicidal patients, and report structural inadequacies in service provision.Conclusions Mental health and primary care services must find innovative and ethical ways to involve families in the decision-making process for patients at risk of suicide
A combined clinical and biomarker approach to predict diuretic response in acute heart failure
Background:
Poor diuretic response in acute heart failure is related to poor clinical outcome. The underlying mechanisms and pathophysiology behind diuretic resistance are incompletely understood. We evaluated a combined approach using clinical characteristics and biomarkers to predict diuretic response in acute heart failure (AHF).
Methods and results:
We investigated explanatory and predictive models for diuretic response—weight loss at day 4 per 40 mg of furosemide—in 974 patients with AHF included in the PROTECT trial. Biomarkers, addressing multiple pathophysiological pathways, were determined at baseline and after 24 h. An explanatory baseline biomarker model of a poor diuretic response included low potassium, chloride, hemoglobin, myeloperoxidase, and high blood urea nitrogen, albumin, triglycerides, ST2 and neutrophil gelatinase-associated lipocalin (r2 = 0.086). Diuretic response after 24 h (early diuretic response) was a strong predictor of diuretic response (β = 0.467, P < 0.001; r2 = 0.523). Addition of diuretic response after 24 h to biomarkers and clinical characteristics significantly improved the predictive model (r2 = 0.586, P < 0.001).
Conclusions:
Biomarkers indicate that diuretic unresponsiveness is associated with an atherosclerotic profile with abnormal renal function and electrolytes. However, predicting diuretic response is difficult and biomarkers have limited additive value. Patients at risk of poor diuretic response can be identified by measuring early diuretic response after 24 h
Serum potassium levels and outcome in acute heart failure (data from the PROTECT and COACH trials)
Serum potassium is routinely measured at admission for acute heart failure (AHF), but
information on association with clinical variables and prognosis is limited. Potassium
measurements at admission were available in 1,867 patients with AHF in the original cohort
of 2,033 patients included in the Patients Hospitalized with acute heart failure and Volume
Overload to Assess Treatment Effect on Congestion and Renal FuncTion trial. Patients
were grouped according to low potassium (<3.5 mEq/l), normal potassium (3.5 to 5.0 mEq/l),
and high potassium (>5.0 mEq/l) levels. Results were verified in a validation cohort of 1,023
patients. Mean age of patients was 71 – 11 years, and 66% were men. Low potassium was
present in 115 patients (6%), normal potassium in 1,576 (84%), and high potassium in 176
(9%). Potassium levels increased during hospitalization (0.18 – 0.69 mEq/l). Patients with
high potassium more often used angiotensin-converting enzyme inhibitors and mineralocorticoid
receptor antagonists before admission, had impaired baseline renal function and a
better diuretic response (p [ 0.005), independent of mineralocorticoid receptor antagonist
usage. During 180-day follow-up, a total of 330 patients (18%) died. Potassium levels at
admission showed a univariate linear association with mortality (hazard ratio [log] 2.36,
95% confidence interval 1.07 to 5.23; p [ 0.034) but not after multivariate adjustment.
Changes of potassium levels during hospitalization or potassium levels at discharge were
not associated with outcome after multivariate analysis. Results in the validation cohort
were similar to the index cohort. In conclusion, high potassium levels at admission are
associated with an impaired renal function but a better diuretic response. Changes in potassium
levels are common, and overall levels increase during hospitalization. In conclusion,
potassium levels at admission or its change during hospitalization are not associated
with mortality after multivariate adjustment
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