Magnetic vortices are characterized by the sense of in-plane magnetization circulation and by the polarity of the vortex core. With each having two possible states, there are four possible stable ...magnetization configurations that can be utilized for a multibit memory cell. Dynamic control of vortex core polarity has been demonstrated using both alternating and pulsed magnetic fields and currents. Here, we show controlled dynamic switching of spin circulation in vortices using nanosecond field pulses by imaging the process with full-field soft X-ray transmission microscopy. The dynamic reversal process is controlled by far-from-equilibrium gyrotropic precession of the vortex core, and the reversal is achieved at significantly reduced field amplitudes when compared with static switching. We further show that both the field pulse amplitude and duration required for efficient circulation reversal can be controlled by appropriate selection of the disk geometry.
Excessive glutamate release followed by N-methyl-d-aspartate receptor (NMDAR) activation plays a crucial role in perinatal brain injury. We have previously shown that dextromethorphan, a low‐affinity ...NMDAR antagonist with anti-inflammatory properties, is neuroprotective against neonatal excitotoxic brain injury. Of interest, dextromethorphan is also a sigma-1 receptor (σ1R) agonist. The pharmacologic class of σ1R agonists has yielded propitious results in various animal models of adult central nervous system pathology. In an established neonatal mouse model of excitotoxic brain injury, we evaluated the effect of the selective σ1R agonist 2-(4-morpholinethyl) 1-phenylcyclohexanecarboxylate (PRE-084). A single intraperitoneal injection of 0.1μg/g (low dose) or 10μg/g (high dose) bodyweight (bw) PRE-084, given 1h after the excitotoxic insult, significantly reduced lesion size in cortical gray matter 24h and 120h after the insult. Repetitive injections of 0.1μg/g PRE-084 proved to be equally effective. PRE-084 treatment resulted in a decrease in cell death indicated by reduced TUNEL positivity and caspase-3 activation. Furthermore, it lowered the number of isolectin B4-positive, activated microglial cells. PRE‐084 had no effect on developmental apoptosis in the undamaged brain. In vitro findings in primary hippocampal neurons suggest that PRE-084 treatment provides partial protection against glutamate induced morphological and functional changes. For excitotoxicity as playing a crucial role in the pathogenesis of perinatal brain injury, we demonstrate for the first time that systemic treatment with the highly selective σ1R agonist PRE-084 protects against NMDAR-mediated excitotoxic brain damage.
► We evaluate neuroprotective effects of a highly selective sigma receptor agonist. ► We use an established mouse model of neonatal excitotoxic brain injury. ► Administration of PRE-084 reduces cell death and microglial cell activation. ► PRE-084 has a beneficial effect in vitro after glutamate exposure. ► Sigma receptor agonists are a potential strategy in perinatal brain injury.
Forming Limit Curve (FLC) is a well-known tool for the evaluation of failure in sheet metal process. However, its experimental determination and evaluation are rather complex. From theoretical point ...of view, FLC describes initiation of the instability not fracture. During the last years Digital Image Correlation (DIC) techniques have been developed extensively. Throughout this paper, all the measurements were done using DIC and as it is reported in the literature, different approaches to capture necking and fracture phenomena using Cross Section Method (CSM), Time dependent Method (TDM) and Thinning Method (TM) were investigated. Each aforementioned method has some advantages and disadvantages. Moreover, a cruciform specimen was used in order to cover whole FLC in the range between uniaxial to equi-biaxial tension and as an alternative for Nakajima test. Based on above-mentioned uncertainty about the fracture strain, some advanced numerical failure models can describe necking and fracture phenomena accurately with consideration of anisotropic effects. It is noticeable that in this paper, dog-bone, notch and circular disk specimens are used to calibrate Johnson-Cook (J-C) fracture model. The results are discussed for mild steel DC01.
. The main goal of the present paper is investigation of the mechanical behaviour of high manganese content steel sheet which is well known in the literature as Twinning-Induced Plasticity (TWIP) ...under linear and nonlinear loading path. Contrary to Nakajima experiment, cruciform specimen under biaxial loading can provide linear and nonlinear strain path. This work aims to determine the numerical Forming Limit Curve (FLC) for TWIP sheet using cruciform specimen under biaxial loading. For this purpose, uniaxial tensile tests are performed on standard dog-bone samples which are extracted from rolling, transversal and diagonal directions to identify the flow curve as well as Lankford ratios. Data are used as input for numerical simulation of cruciform specimen. Results show the applicability of cruciform specimen for linear and nonlinear strain paths.
Context: Polycystic ovary syndrome (PCOS) is a common endocrine disorder that is believed to have a genetic basis. However, no specific susceptibility gene or region has been conclusively identified.
...Objective: The objective of this study was to duplicate a previous study that localized a PCOS susceptibility region to chromosome 19p13.2 and to narrow the susceptibility region.
Design: This study was designed to test for genetic linkage and association between PCOS and short tandem repeat polymorphisms in 367 families, by analysis of linkage and family-based association.
Setting: The study was conducted at academic medical centers.
Patients or Other Participants: We studied 367 families of predominantly European origin with at least one PCOS patient. Families included 107 affected sibling (sister) pairs (ASPs) in 83 families, and 390 trios with both parents and an affected daughter. The data set comprises two independent groups. Set 1 consists of 44 ASPs and 163 trios. Set 2 consists of 63 ASPs and 227 trios.
Intervention(s): The intervention was the drawing of blood for DNA extraction.
Main Outcome Measure: We employed measures of evidence for linkage and association between PCOS and 19 STRs.
Results: Linkage with PCOS was observed over a broad region of chromosome 19p13.2. The strongest evidence for association was observed with D19S884 (χ2=11.85; nominal P < 0.0006; permutation P = 0.034) and duplicated our earlier findings.
Conclusions: The present analysis suggests that a PCOS susceptibility locus maps very close to D19S884. Additional studies that systematically characterize DNA sequence variation in the immediate area of D19S884 are required to identify the PCOS susceptibility variant.
Hypoxia–ischaemia (HI) is a major factor in the pathogenesis of developmental brain injury, leading to cognitive deficits and motor disabilities in preterm infants. The haematopoietic growth factor ...granulocyte colony-stimulating factor (G-CSF) has been shown to exert a neuroprotective activity in rodent models of ischaemic stroke and is currently subject to phase I/II clinical trials in adults. Results of studies examining the effect of G-CSF in perinatal brain damage have been contradictory. We have previously shown that G-CSF increases NMDAR-mediated excitotoxic brain injury in the neonatal mouse brain.
In this study, we evaluated the effect of G-CSF on long-term outcomes after HI. On postnatal day 5, mice pubs were first randomly assigned to a sham operation or HI and then divided into four treatment groups: i) G-CSF; ii) phosphate buffered saline (PBS) 1h after injury; iii) G-CSF and iv) PBS 60h after injury. G-CSF (200μg/kg BW) was administered five times within a 24h interval. Neuromotor and cognitive outcomes were assessed by open-field, novel object recognition tests and rotarod tests starting on P90, with subsequent histological analyses of brain injury.
G-CSF treatment did not improve either neurobehavioural outcomes or brain injuries. Interestingly, the application of PBS and G-CSF in the acute phase increased brain damage in the hippocampus. We could not confirm the neuroprotective properties of G-CSF in neonatal HI brain damage. The exacerbation of injury by the administration of substances in the acute phase might indicate a heightened state of neurological sensitivity that is specific to mechanisms of secondary neurodegeneration and influenced by unidentified external factors possibly associated with the treatment protocol during the acute phase. This article is part of a Special Issue entitled "Interaction between repair, disease, & inflammation."
► G-CSF treatment does not improve brain injury in newborn mice after hypoxia–ischaemia. ► CSF treatment does not improve neurobehavioural long-term outcomes. ► Any substance injection in the acute phase after injury exacerbates brain injury.
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