746 research outputs found
Kondo Effect in Defect-bound Quantum Dots Coupled to NbSe
We report the fabrication of a van der Waals tunneling device hosting a
defect-bound quantum dot coupled to NbSe. We find that upon application of
magnetic field, the device exhibits a zero-bias conductance peak. The peak,
which splits at higher fields, is associated with a Kondo effect. At the same
time, the junction retains conventional quasiparticle tunneling features at
finite bias. Such coexistence of a superconducting gap and a Kondo effect are
unusual, and are explained by noting the two-gap nature of the superconducting
state of NbSe, where a magnetic field suppresses the low energy gap
associated with the Se band. Our data shows that van der Waals architectures,
and defect-bound dots in them, can serve as a novel and effective platform for
investigating the interplay of Kondo screening and superconducting pairing in
unconventional superconductors
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Prophylaxis pharmacotherapy to prevent the onset of post traumatic brain injury depression: a systematic review
YesBackground: Depression is a common psychiatric problem following traumatic brain injury (TBI) with reported prevalence rates of 30-77% in the first year post-TBI. Given the negative influence of post-TBI depression on cognition, interpersonal, social, physical and occupational functioning; early initiation of pharmacotherapy to prevent post-TBI depression has been considered. This systematic review will synthesize the available evidence from published studies on the effectiveness and harms of pharmacotherapy for the secondary prevention of post-TBI depression.
Method: Studies published before November 2017 were reviewed. Six databases were searched, with additional searching of key additional documents. Studies meeting inclusion criteria were evaluated for methodological quality.
Results: Six articles addressing five studies met inclusion criteria. Study designs included three randomised controlled trials (RCT), two retrospective cohorts and one case-control. Prophylactic pharmacotherapy included antidepressants, beta-blockers and statins. In one RCT, the number-needed-to-treat with sertraline to prevent one case of depression post-TBI at 24 weeks was 5.9 (95%CI: 3.1-71.1). Prescribing beta-blockers prior to TBI reduced the depression risk regardless of the specific brain trauma. TBI patients with pre-existing hyperlipidemia not treated with statins had an increased depression risk compared to those without hyperlipidemia.
Conclusion: Early initiation of sertraline prophylaxis in nondepressed TBI patients shows promise to reduce the odds of post-TBI depression developing. However, in the absence of rigorous study of tolerability, existing data are insufficient to recommend sertraline prophylaxis. Optimal timing and treatment duration with identification of patients most likely to benefit from prophylaxis require further consideration. Dedicated prospective studies assessing the effects of beta-blockers and statins on post-TBI depression are required.The Transport Accident Commission (TAC), through the Institute for Safety, Compensation and Recovery Research (ISCRR) at Monash University, provided funding for this review
A new measurement of the 7Li(d,p)8Li cross section and consequences for 7Be(p,gamma)8B
A novel scheme for measuring the cross section of the 7Be(p,gamma)8B
reaction, the major source of high energy neutrinos from t he sun, is
presented. The scheme involves a strictly uniform particle beam and overcomes
some of the recognized experimental uncertainties of previous measurements. A
new measurement of sigma[7Li(d,p)8Li] has been carried out using this setup,and
the present value of sigma[7Li(d,p)8Li] = 155(8) mbarn at the top of the
E_d(lab.)= 776 keV resonance is compared to previous measurements. A new issue
regarding both the (d,p) and (p,gamma) reactions has been examined:
reaction-product nuclei which are backscattered out of the target. Measurements
and simulations carried out in the course of this investigation are presented
and discussed in the context of possible effects on the measured cross sections
of these reactions.Comment: 4 figure
Paradoxical augmented relapse in alcohol-dependent rats during deep-brain stimulation in the nucleus accumbens
Case reports indicate that deep-brain stimulation in the nucleus accumbens may
be beneficial to alcohol-dependent patients. The lack of clinical trials and
our limited knowledge of deep-brain stimulation call for translational
experiments to validate these reports. To mimic the human situation, we used a
chronic-continuous brain-stimulation paradigm targeting the nucleus accumbens
and other brain sites in alcohol-dependent rats. To determine the network
effects of deep-brain stimulation in alcohol-dependent rats, we combined
electrical stimulation of the nucleus accumbens with functional magnetic
resonance imaging (fMRI), and studied neurotransmitter levels in nucleus
accumbens-stimulated versus sham-stimulated rats. Surprisingly, we report here
that electrical stimulation of the nucleus accumbens led to augmented relapse
behavior in alcohol-dependent rats. Our associated fMRI data revealed some
activated areas, including the medial prefrontal cortex and caudate putamen.
However, when we applied stimulation to these areas, relapse behavior was not
affected, confirming that the nucleus accumbens is critical for generating
this paradoxical effect. Neurochemical analysis of the major activated brain
sites of the network revealed that the effect of stimulation may depend on
accumbal dopamine levels. This was supported by the finding that brain-
stimulation-treated rats exhibited augmented alcohol-induced dopamine release
compared with sham-stimulated animals. Our data suggest that deep-brain
stimulation in the nucleus accumbens enhances alcohol-liking probably via
augmented dopamine release and can thereby promote relapse
Gender, war and militarism: making and questioning the links
The gender dynamics of militarism have traditionally been seen as straightforward, given the cultural mythologies of warfare and the disciplining of ‘masculinity’ that occurs in the training and use of men's capacity for violence in the armed services. However, women's relation to both war and peace has been varied and complex. It is women who have often been most prominent in working for peace, although there are no necessary links between women and opposition to militarism. In addition, more women than ever are serving in many of today's armies, with feminists rather uncertain on how to relate to this phenomenon. In this article, I explore some of the complexities of applying gender analyses to militarism and peace work in sites of conflict today, looking most closely at the Israeli feminist group, New Profile, and their insistence upon the costs of the militarized nature of Israeli society. They expose the very permeable boundaries between the military and civil society, as violence seeps into the fears and practices of everyday life in Israel. I place their work in the context of broader feminist analysis offered by researchers such as Cynthia Enloe and Cynthia Cockburn, who have for decades been writing about the ‘masculinist’ postures and practices of warfare, as well as the situation of women caught up in them. Finally, I suggest that rethinking the gendered nature of warfare must also encompass the costs of war to men, whose fundamental vulnerability to psychological abuse and physical injury is often downplayed, whether in mainstream accounts of warfare or in more specific gender analysis. Feminists need to pay careful attention to masculinity and its fragmentations in addressing the topic of gender, war and militarism
Effect of Plant Preservative Mixture Ppmtm on the Shoot Regeneration of Watercress (Nasturtium Officinale)
Plant Preservative Mixture™ (PPM), a relatively new broad-spectrum preservative and biocide for use in plant tissue culture, was evaluated as an alternative to the use of conventional antibiotics and fungicides in plant tissue culture. Culture inoculated in MS media supplemented with PPM (1.5 ml/l) was the effective concentration which gave the best values. The top values were recorded for all studied characters using apical buds compared with lateral buds. The combination between apical buds and (1.5 ml/l ) PPM concentration showed the superior values of all studied parameters( 33.25%,19.40%, 14.46%,20.53% and 79.46%)(60.55%,39.80%,20.97%,45.33% and 54.44%) and (31.20%, 20. 06%, 12.33%, 35.13% and 81.06 %) for contamination, %bacterial contamination, % offungi contamination, dead explants% and survival explants% respectively. Different concentrations of PPM (0, 0.5, 1.0, 1.5, 2.0 and 2.5 ml/l) were tested using single node and apex explants of watercress (Nasturtium officinale). PPM at (1.5ml/l) had significant effect on the studied characters; shoots height, shoots number, leaf pairs number, fresh and dry weight which they reaches (4.16, 4.62, 42.00,0.524 and 0.063 g, respectively ). Apex bud explants showed the greatest effect on shoots height shoots number, leaf pairs number, fresh and dry weight and their values were 3.52, 32.02, 3.38, 0.405 and 0.036 g, respectively. The best parameter were recorded on MS media supplemented with PPM at (1.5ml/l) with apex buds explant (4.55, 5.34, 46.28, 0.570 and 0.085, respectively) for shoots height, shoots number, leaf pair number, fresh and dry weight. Current study aimed to determine the best concentration of PPM for limiting the contamination of watercress and micro shoot regeneration
Minocycline rescues decrease in neurogenesis, increase in microglia cytokines and deficits in sensorimotor gating in an animal model of schizophrenia
Adult neurogenesis in the hippocampus is impaired in schizophrenic patients and in an animal model of schizophrenia. Amongst a plethora of regulators, the immune system has been shown repeatedly to strongly modulate neurogenesis under physiological and pathological conditions. It is well accepted, that schizophrenic patients have an aberrant peripheral immune status, which is also reflected in the animal model. The microglia as the intrinsic immune competent cells of the brain have recently come into focus as possible therapeutic targets in schizophrenia. We here used a maternal immune stimulation rodent model of schizophrenia in which polyinosinic-polycytidilic acid (Poly I:C) was injected into pregnant rats to mimic an anti-viral immune response. We identified microglia IL-1{beta} and TNF-{alpha} increase constituting the factors correlating best with decreases in net-neurogenesis and impairment in pre-pulse inhibition of a startle response in the Poly I:C model. Treatment with the antibiotic minocycline (3mg/kg/day) normalized microglial cytokine production in the hippocampus and rescued neurogenesis and behavior. We could also show that enhanced microglial TNF-{alpha} and IL-1{beta} production in the hippocampus was accompanied by a decrease in the pro-proliferative TNFR2 receptor expression on neuronal progenitor cells, which could be attenuated by minocycline. These findings strongly support the idea to use anti-inflammatory drugs to target microglia activation as an adjunctive therapy in schizophrenic patients
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