Plasmoids Formation During Simulations of Coaxial Helicity Injection in the National Spherical Torus Experiment.

The formation of an elongated Sweet-Parker current sheet and a transition to plasmoid instability has for the first time been predicted by simulations in a large-scale toroidal fusion plasma in the absence of any preexisting instability. Plasmoid instability is demonstrated through resistive MHD simulations of transient coaxial helicity injection experiments in the National Spherical Torus Experiment (NSTX). Consistent with the theory, fundamental characteristics of the plasmoid instability, including fast reconnection rate, have been observed in these realistic simulations. Motivated by the simulations, experimental camera images have been revisited and suggest the existence of reconnecting plasmoids in NSTX. Global, system-size plasmoid formation observed here should also have strong implications for astrophysical reconnection, such as rapid eruptive solar events.

Helicity-flux-driven α effect in laboratory and astrophysical plasmas.

The constraint imposed by magnetic helicity conservation on the α effect is considered for both magnetically and flow dominated self-organizing plasmas. Direct numerical simulations are presented for a dominant contribution to the α effect, which can be cast in the functional form of a total divergence of an averaged helicity flux, called the helicity-flux-driven α (Hα) effect. Direct numerical simulations of the Hα effect are presented for two examples-the magnetically dominated toroidal plasma unstable to tearing modes, and the flow-dominated accretion disk.

Early results of stand-alone anterior lumbar interbody fusion in iatrogenic spondylolisthesis patients.

BACKGROUND: Iatrogenic spondylolisthesis is a challenging condition for spinal surgeons. Posterior surgery in these cases is complicated by poor anatomical landmarks, scar tissue adhesion of muscle and dural structures and difficult access to the intervertebral disc. Anterior interbody fusion provides an alternative treatment method, allowing indirect foraminal decompression, reliable disc clearance and implantation of large surface area implants. MATERIALS AND METHODS: A retrospective chart review of patients with iatrogenic spondylolisthesis including pre- and post-operative Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) scores was performed. Imaging criteria were pelvic incidence, overall lumbar lordosis and segmental lordosis. In addition, the fusion rate was investigated after 6 months. RESULTS: Six consecutive patients treated between 2008 and 2011 (4 female, 2 male, mean age 61 ± 7.1 years) were identified. The initially performed surgeries included decompression with or without discectomy; posterior instrumented and non-instrumented fusion. The olisthetic level was in all cases at the decompressed level. All patients were revised with stand-alone anterior interbody fusion devices at the olisthetic level filled with BMP 2. Average ODI dropped from 49 ± 11 % pre-operatively to 26.0 ± 4.0 at 24 months follow-up. VAS average dropped from 7 ± 1 to 2 ± 0. Mean total lordosis of 39.8 ± 2.8° increased to 48.5 ± 4.9° at pelvic incidences of 48.8 ± 6.8° pre-operatively. Mean segmental lordosis at L4/5 improved from 10.5 ± 6.7° to 19.0 ± 4.9° at 24 months. Mean segmental lordosis in L5/S1 increased from 15.1 ± 7.4° to 23.2 ± 5.6°. Cage subsidence due to severe osteoporosis occurred in one case after 5 months, and hence there was no further follow-up. Fusion was confirmed in all other patients. CONCLUSION: Anterior interbody fusion offers good stabilisation and restoration of lordosis in iatrogenic spondylolisthesis and avoids the well-known problems associated with reentering the spinal canal for revision fusions. In this group, ODI and VAS scores were improved.

Experimental evidence for a reduction in electron thermal diffusion due to trapped particles.

New high time resolution measurements of the electron thermal diffusion χ(e) throughout the sawtooth cycle of the Madison Symmetric Torus reversed-field pinch have been made by utilizing the enhanced capabilities of the upgraded multipoint, multipulse Thomson scattering system. These measurements are compared to the χ(e) due to magnetic diffusion predicted by using information from a new high spectral resolution zero-ß nonlinear resistive magnetohydrodynamic simulation performed, for the first time, at the Lundquist number of high current Madison Symmetric Torus plasmas (S≈4×10(6)). Agreement between the measured and predicted values is found only if the reduction in thermal diffusion due to trapped particles is taken into account.

Intestinal alkaline phosphatase preserves the normal homeostasis of gut microbiota.

BACKGROUND AND AIMS: The intestinal microbiota plays a critical role in maintaining human health; however, the mechanisms governing the normal homeostatic number and composition of these microbes are largely unknown. Previously it was shown that intestinal alkaline phosphatase (IAP), a small intestinal brush border enzyme, functions as a gut mucosal defence factor limiting the translocation of gut bacteria to mesenteric lymph nodes. In this study the role of IAP in the preservation of the normal homeostasis of the gut microbiota was investigated. METHODS: Bacterial culture was performed in aerobic and anaerobic conditions to quantify the number of bacteria in the stools of wild-type (WT) and IAP knockout (IAP-KO) C57BL/6 mice. Terminal restriction fragment length polymorphism, phylogenetic analyses and quantitative real-time PCR of subphylum-specific bacterial 16S rRNA genes were used to determine the compositional profiles of microbiotas. Oral supplementation of calf IAP (cIAP) was used to determine its effects on the recovery of commensal gut microbiota after antibiotic treatment and also on the colonisation of pathogenic bacteria. RESULTS: IAP-KO mice had dramatically fewer and also different types of aerobic and anaerobic microbes in their stools compared with WT mice. Oral supplementation of IAP favoured the growth of commensal bacteria, enhanced restoration of gut microbiota lost due to antibiotic treatment and inhibited the growth of a pathogenic bacterium (Salmonella typhimurium). CONCLUSIONS: IAP is involved in the maintenance of normal gut microbial homeostasis and may have therapeutic potential against dysbiosis and pathogenic infections.

Olfactory neurons are interdependent in maintaining axonal projections.

In mice, individual olfactory neurons express one of the thousand distinct olfactory receptor genes [1] [2] [3]. Neurons that express a given receptor converge on distinct loci in the olfactory bulb to form structures called glomeruli [4] [5] [6]. The olfactory receptor is involved in an instructive manner in this axonal convergence [6] [7] but little is known about the mechanisms involved in maintaining convergence. We have previously created a transgenic olfactory receptor locus that functions independently of the endogenous loci [8]. Here, we show that, although the projections of neurons expressing this ectopic transgenic olfactory receptor always converge in newborn mice, surprisingly, in adult mice, convergence is not always maintained. Moreover, in adult mice there is a positive correlation between the number of neurons expressing the transgenic receptor and the probability of maintaining convergence. These observations, taken together with the variability observed in wild-type [4] [6] and genetically manipulated mice ([6] and our unpublished observations), suggest that olfactory neurons require the presence of other similar axons to maintain a glomerulus. We call this phenomenon interdependence.

Olfactory G proteins: simple and complex signal transduction.

In both vertebrates and invertebrates, olfactory perception is mediated by G-protein-coupled receptors. Recent work, in both mouse and Caenorhabditis elegans, sheds light on the role of specific G proteins in olfactory signal transduction, neuronal morphology and axon guidance.

The specification of olfactory neurons.

Recent studies have shed light on the different relationships between odorant receptor expression and the specification of neural identity in the olfactory systems of vertebrates and invertebrates. In mice, neuronal identity and axon guidance are specified by the single expressed olfactory receptor, whereas in C. elegans, neuronal identity appears to be independent of receptor expression.

Pulmonary complications in primary hypogammaglobulinemia: a survey by high resolution CT scan.

BACKGROUND: Primary hypogammaglobulinemia disorders are a group of heterogeneous immunodeficiency syndromes with an increased susceptibility to pulmonary complications. METHODS: The aim of this study was to evaluate the extent of lung abnormalities in primary hypogammaglobulinaemic patients by high resolution computed tomography (HRCT) scan and pulmonary function test (PFT). HRCT and PFT were performed in 22 Iranian patients with primary hypogammaglobulinemia. RESULTS: Pathological bronchial findings were observed in thirteen patients: three patients showed only peribronchial thickening and the remaining ten patients suffered from both bronchiectasis and peribronchial wall thickening. Mild type of bronchiectasis and peribronchial wall thickening were the most common type, predominantly observed in the right middle and both right and left lower lobe segments of lungs. Although bullae were not found, emphysema, air-trapping, and collapse/consolidation were observed in two patients. Bronchial involvement was mostly limited to 1 up to 5 bronchopulmonary segments; only one HRCT indicated bronchial involvement in more than nine bronchopulmonary segments. Pathological bronchial findings mostly observed in the proximal bronchi; meanwhile the involvement of the distal bronchi was less common. Decreasing FEVI and FVC were observed in 65% and 55% of patients, respectively. There was a significant correlation between the HRCT score and the predicted values by PFT. The delay of diagnosis in patients with bronchiectasis was significantly higher than those without bronchiectasis. CONCLUSIONS: It seems that the majority of hypogammaglobulinaemic patients suffer from the mild type of bronchiectasis, which is mostly observed in the proximal bronchi of the lower lobe segments. The delay of diagnosis plays an important role in the occurrence of this complication in these patients.

Effect of teaching stress management skills on self-esteem and behavioral adjustment in people with somatomotor disabilities.

Objective: Psychological interventions for enhancing mental health in those with somatomotor-physical disabilities are vital. The existing research aimed to examine the effect of teaching stress management skills on self-esteem and behavioral adjustment in individuals with somatomotor-physical disabilities. Methodology: The method of the survey was semi-experimental with a pre-test post-test design and a control group. Hence, in Tehran, 40 girls with somatomotor-physical disabilities were selected by using convenience sampling, and they were divided into two groups: control and experiment. Both groups were tested by using a demography questionnaire, Rozenberg's self-esteem scale, and a behavioral adjustment questionnaire. Afterwards, the test group received lessons on stress management within ten sessions, but the control group received no interventions. Then both groups were post-tested, and the collected data were analyzed by using descriptive and inferential statistics methods through SPSS software. Findings: Findings showed that teaching stress management skills significantly increased self-esteem and behavioral adjustment in girls with somatomotor-physical disabilities (p < 0.001). Conclusion: According to the study, it could be concluded that teaching stress management skills is an effective way to help endangered individuals such as girls who have somatomotor-physical disabilities because it is highly efficient especially when it is performed in groups, it is cheap, and acceptable by different people.

Absence of complete finite-Larmor-radius stabilization in extended MHD.

The dominant finite-Larmour-radius (FLR) stabilization effects on interchange instability can be retained by taking into account the ion gyroviscosity or the generalized Ohm's law in an extended MHD model. However, recent simulations and theoretical calculations indicate that complete FLR stabilization of the interchange mode may not be attainable by ion gyroviscosity or the two-fluid effect alone in the framework of extended MHD. For a class of plasma equilibria in certain finite-beta or nonisentropic regimes, the critical wave number for complete FLR stabilization tends toward infinity.

Assessment of Itakura Distance as a valuable feature for computer-aided classification of sleep stages.

Staging and detection of various states of sleep derived from EEG and other biomedical signals have proven to be very helpful in diagnosis, prognosis and remedy of various sleep related disorders. The time consuming and costly process of visual scoring of sleep stages by a specialist has always motivated researchers to develop an automatic sleep scoring system and the first step toward achieving this task is finding discriminating characteristics (or features) for each stage. A vast variety of these features and methods have been investigated in the sleep literature with different degrees of success. In this study, we investigated the performance of a newly introduced measure: the Itakura Distance (ID), as a similarity measure between EEG and EOG signals. This work demonstrated and further confirmed the outcomes of our previous research that the Itakura Distance serves as a valuable similarity measure to differentiate between different sleep stages.

Momentum transport from current-driven reconnection in the reversed field pinch.

We calculate momentum transport from tearing fluctuations in a reversed field pinch with sheared flow, considering both the effect of a single tearing mode (through quasilinear theory and MHD computation) and multiple tearing modes (through nonlinear MHD computation). A single tearing mode transports momentum, via Maxwell and Reynolds stresses, more rapidly than classical viscous forces. Moreover, the transport is enhanced by nonlinear coupling of multiple modes.

Cause of sudden magnetic reconnection in a laboratory plasma.

The cause for sudden reconnection in reversed field pinch plasmas is determined experimentally for two cases: large reconnection events (the sawtooth crash) and small reconnection events during improved confinement. We measure the term in the MHD equations which represents the driving (or damping) of edge tearing modes due to the axisymmetric magnetic field. The term is negative for large reconnection events (the modes are stable, implying that reconnection may be driven by nonlinear coupling to other modes) and positive for small reconnection events (modes are unstable, reconnection is spontaneous).

Fracture behavior of urinary stones under compression.

The fracture behavior of two types of urinary stones, namely struvite and calcium oxalate, during compression testing was studied. Scanning electron microscopy (SEM) was used to characterize the fracture surfaces. Both types of stone showed pseudo-plastic behavior as indicated by their load-displacement curve. The onset of nonlinear behavior was found to correspond to development of microcracks in the specimens. The compressive strength was defined as the stress calculated at the maximum load. In struvite samples, the maximum load corresponded with the development of large cracks parallel to the compressive axis. For oxalate stones a separation of the outer layer (crust) from the inner layer (core) marked the point of maximum load. The compressive strength of the struvite samples was found to depend on the orientation of lamellae relative to the loading axis. Struvite stones, when loaded parallel to the lamination direction showed a higher compressive strength than oxalate stones did. The fracture behavior and compressive strength of a model material (z-brick) were also characterized and compared to those of the urinary stones.

YAC transgene-mediated olfactory receptor gene choice.

In the mouse, individual olfactory neurons express one of a thousand distinct olfactory receptor genes. Furthermore, only one allele of the expressed gene is transcribed. This phenomenon, random allelic inactivation, along with the observation that the olfactory receptor genes reside in large chromosomal arrays, suggests a role for long-range gene regulation in olfactory receptor gene choice. We have constructed a 300-kb yeast artificial chromosome (YAC) transgene in which a single receptor gene is marked while maintaining its coding region. This 300-kb piece of DNA functions as an independent olfactory receptor gene locus in directing olfactory receptor gene choice in both the olfactory system and the accessory olfactory system (vomeronasal organ, VNO). Furthermore, the transgene, like endogenous olfactory receptor loci, is subject to allelic inactivation.