545 research outputs found
A quality assessment of Spatial TDR soil moisture measurements in homogenous and heterogeneous media with laboratory experiments
Investigation of transient soil moisture profiles yields valuable information of near- surface processes. A recently developed reconstruction algorithm based on the telegraph equation allows the inverse estimation of soil moisture profiles along coated, three rod TDR probes. Laboratory experiments were carried out to prove the results of the inversion and to understand the influence of probe rod deformation and solid objects close to the probe in heterogeneous media. Differences in rod geometry can lead to serious misinterpretations in the soil moisture profile, but have small influence on the average soil moisture along the probe. Solids in the integration volume have almost no effect on average soil moisture, but result in locally slightly decreased moisture values. Inverted profiles obtained in a loamy soil with a clay content of about 16% were in good agreement with independent measurements
Outcomes of surgical treatment of non-metastatic gastric cancer in patients aged 70 and older:A systematic review and meta-analysis
The optimal surgical treatment strategy for gastric cancer in older patients needs to be carefully evaluated due to increased vulnerability of older patients. We performed a database search for randomized controlled trials (RCTs) and cohort studies that included patients ≥70 years with potentially resectable stage I-III gastric cancer. Postoperative and survival outcomes were compared between groups undergoing 1) gastrectomy vs conservative treatment (best supportive care or non-operative treatment), 2) minimally invasive (MIG) vs open gastrectomy (OG), or 3) extended vs limited lymphadenectomy. When possible, results were pooled using risk ratios (RR). Thirty-one studies were included. Six retrospective studies compared overall survival (OS) between gastrectomy (N = 2332) and conservative treatment (N = 246). Longer OS was reported in the gastrectomy group in all studies, but study quality was low and meta-analysis was not feasible. Eighteen cohort studies compared MIG (N = 3626) and OG (N = 5193). MIG was associated with fewer complications (pooled RR 0.68, 95% confidence interval 0.54–0.84). OS was not different between the groups. Two RCTs and five cohort studies compared outcomes between extended (N = 709) and limited lymphadenectomy (N = 1323). Complication rates were comparable between the groups. Two cohort studies found longer OS or cancer-specific survival after extended lymphadenectomy. No quality of life (QoL) or functional outcomes were reported. In older patients with gastric cancer, there is low-quality evidence for better OS after gastrectomy vs conservative treatment. Compared to OG, MIG was associated with less postoperative morbidity. The evidence to support extended lymphadenectomy is limited. QoL and functional outcomes should be addressed in future studies
Spintronics: Fundamentals and applications
Spintronics, or spin electronics, involves the study of active control and
manipulation of spin degrees of freedom in solid-state systems. This article
reviews the current status of this subject, including both recent advances and
well-established results. The primary focus is on the basic physical principles
underlying the generation of carrier spin polarization, spin dynamics, and
spin-polarized transport in semiconductors and metals. Spin transport differs
from charge transport in that spin is a nonconserved quantity in solids due to
spin-orbit and hyperfine coupling. The authors discuss in detail spin
decoherence mechanisms in metals and semiconductors. Various theories of spin
injection and spin-polarized transport are applied to hybrid structures
relevant to spin-based devices and fundamental studies of materials properties.
Experimental work is reviewed with the emphasis on projected applications, in
which external electric and magnetic fields and illumination by light will be
used to control spin and charge dynamics to create new functionalities not
feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes
from the published versio
Early changes in biochemical markers of bone turnover and their relationship with bone mineral density changes after 24 months of treatment with teriparatide
Summary
We report the changes in biochemical markers of bone formation during the first 6 months of teriparatide therapy in postmenopausal women with osteoporosis according to previous antiresorptive treatment. Prior therapy does not adversely affect the response to teriparatide treatment. Similar bone markers levels are reached after 6 months of treatment.
Introduction
The response of biochemical markers of bone turnover with teriparatide therapy in subjects who have previously received osteoporosis drugs is not fully elucidated. We examined biochemical markers of bone formation in women with osteoporosis treated with teriparatide and determined: (1) whether the response is associated with prior osteoporosis therapy, (2) which marker shows the best performance for detecting a response to therapy, and (3) the correlations between early changes in bone markers and subsequent bone mineral density (BMD) changes after 24 months of teriparatide.
Methods
We conducted a prospective, open-label, 24-month study at 95 centers in 10 countries in 758 postmenopausal women with established osteoporosis (n = 181 treatment-naïve) who had at least one post-baseline bone marker determination. Teriparatide (20 μg/day) was administered for up to 24 months. We measured procollagen type I N-terminal propeptide (PINP), bone-specific alkaline phosphatase (b-ALP), and total alkaline phosphatase (t-ALP) at baseline, 1 and 6 months, and change in BMD at the lumbar spine, total hip and femoral neck from baseline to 24 months.
Results
Significant increases in formation markers occurred after 1 month of teriparatide regardless of prior osteoporosis therapy. The absolute increase at 1 month was lower in previously treated versus treatment-naïve patients, but after 6 months all groups reached similar levels. PINP showed the best signal-to-noise ratio. Baseline PINP correlated positively and significantly with BMD response at 24 months.
Conclusions
This study suggests that the long-term responsiveness of bone formation markers to teriparatide is not affected in subjects previously treated with antiresorptive drugs
Prognostic factors in 264 adults with invasive Scedosporium spp. and Lomentospora prolificans infection reported in the literature and FungiScope
Invasive Scedosporium spp. and Lomentospora prolificans infections are an emerging threat in
immunocompromised and occasionally in healthy hosts. Scedosporium spp. is intrinsically resistant
to most, L. prolificans to all the antifungal drugs currently approved, raising concerns about
appropriate treatment decisions. High mortality rates of up to 90% underline the need for comprehensive
diagnostic workup and even more for new, effective antifungal drugs to improve
patient outcome. For a comprehensive analysis, we identified cases of severe Scedosporium spp.
and L. prolificans infections from the literature diagnosed in 2000 or later and the FungiScopeVR
registry. For 208 Scedosporium spp. infections solid organ transplantation (n¼58, 27.9%) and for
56 L. prolificans infection underlying malignancy (n¼28, 50.0%) were the most prevalent risk factors.
L. prolificans infections frequently presented as fungemia (n¼26, 46.4% versus n¼12, 5.8%
for Scedosporium spp.). Malignancy, fungemia, CNS and lung involvement predicted worse outcome
for scedosporiosis and lomentosporiosis. Patients treated with voriconazole had a better
overall outcome in both groups compared to treatment with amphotericin B formulations. This
review discusses the epidemiology, prognostic factors, pathogen susceptibility to approved and
investigational antifungals, and treatment strategies of severe infections caused by Scedosporium
spp. and L. prolificans
The effects of acute tryptophan depletion on costly information sampling: impulsivity or aversive processing?
RATIONALE: The neurotransmitter serotonin (5-HT) has been implicated in both aversive processing and impulsivity. Reconciling these accounts, recent studies have demonstrated that 5-HT is important for punishment-induced behavioural inhibition. These studies focused on situations where actions lead directly to punishments. However, decision-making often involves making tradeoffs between small 'local' costs and larger 'global' losses. OBJECTIVE: We aimed to distinguish whether 5-HT promotes avoidance of local losses, global losses, or both, in contrast to an overall effect on reflection impulsivity. We further examined the influence of individual differences in sub-clinical depression, anxiety and impulsivity on global and local loss avoidance. METHODS: Healthy volunteers (N = 21) underwent an acute tryptophan depletion procedure in a double-blind, placebo-controlled crossover design. We measured global and local loss avoidance in a decision-making task where subjects could sample information at a small cost to avoid making incorrect decisions, which resulted in large losses. RESULTS: Tryptophan depletion removed the suppressive effects of small local costs on information sampling behaviour. Sub-clinical depressive symptoms produced effects on information sampling similar to (but independent from) those of tryptophan depletion. Dispositional anxiety was related to global loss avoidance. However, trait impulsivity was unrelated to information sampling. CONCLUSIONS: The current findings are consistent with recent theoretical work that characterises 5-HT as pruning a tree of potential decisions, eliminating options expected to lead to aversive outcomes. Our results extend this account by proposing that 5-HT promotes reflexive avoidance of relatively immediate aversive outcomes, potentially at the expense of more globally construed future losses
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