Primordial metallic melt in the deep mantle

Seismic tomography models reveal two large low shear velocity provinces (LLSVPs) that identify large-scale variations in temperature and composition in the deep mantle. Other characteristics include elevated density, elevated bulk sound speed, and sharp boundaries. We show that properties of LLSVPs can be explained by the presence of small quantities (0.3–3%) of suspended, dense Fe-Ni-S liquid. Trapping of metallic liquid is demonstrated to be likely during the crystallization of a dense basal magma ocean, and retention of such melts is consistent with currently available experimental constraints. Calculated seismic velocities and densities of lower mantle material containing low-abundance metallic liquids match the observed LLSVP properties. Small quantities of metallic liquids trapped at depth provide a natural explanation for primitive noble gas signatures in plume-related magmas. Our model hence provides a mechanism for generating large-scale chemical heterogeneities in Earth's early history and makes clear predictions for future tests of our hypothesis

Predictors of Recovery from Prenatal Depressive Symptoms from Pregnancy Through Postpartum

Abstract Background: Identifying predictors of the course of depressive symptoms from pregnancy through postpartum is important to inform clinical interventions. Methods: This longitudinal study investigated predictors of recovery from prenatal elevated depressive symptoms in the postpartum period. Forty-one pregnant women completed demographic, interpersonal, and psychosocial self-report assessment measures at 32 weeks of gestation and again 12 weeks postpartum. Results: Of those with elevated depressive symptoms, defined as a Beck Depression Inventory-II (BDI-II) score ≥10, at the prenatal baseline, 39% (n=16) recovered to nonelevated symptom levels postpartum, whereas 61% (n=25) experienced sustained elevated symptoms. Women who recovered evidenced significantly lower baseline depression severity and more frequent engagement in physical activity and cohabitated with a romantic partner. In multiparous women (n=25), history of past postpartum depression (PPD) differentiated between those with transient and those with persisting symptoms, although history of lifetime depression did not. None of the additional demographic, interpersonal, or psychosocial variables investigated differentiated between groups. Logistic regression analysis showed prenatal depression severity and exercise frequency as predictors of recovery postpartum. Conclusions: Results suggest most women will not experience spontaneous recovery. Women with prenatal heightened symptom severity and previous experiences with PPD are acutely vulnerable to experience sustained symptoms. In contrast, having a cohabitating partner and engagement in prenatal exercise predicted symptom improvement. Physical exercise may be an important clinical recommendation, as it may improve mood. Given the small sample size, these results are preliminary. Implications and future research recommendations are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98461/1/jwh%2E2010%2E2266.pd

Exercise and manual auricular acupuncture: a pilot assessor-blind randomised controlled trial

Abstract Background Evidence supports the use of exercise for chronic low back pain (CLBP); however, adherence is often poor due to ongoing pain. Auricular acupuncture is a form of pain relief involving the stimulation of points on the outer ear corresponding with specific body parts. It may be a useful adjunct to exercise in managing CLBP; however, there is only limited evidence to support its use with this patient group. Methods/Design This study was designed to test the feasibility of an assessor-blind randomised controlled trial which assess the effects on clinical outcomes and exercise adherence of adding manual auricular acupuncture to a personalised and supervised exercise programme (PEP) for CLBP. No sample size calculation has been carried out as this study aims to identify CLBP referral rates within the catchment area of the study site. The researchers aim to recruit four cohorts of n = 20 participants to facilitate a power analysis for a future randomised controlled trial. A computer generated random allocation sequence will be prepared centrally and used to allocate participants by cohort to one of the following interventions: 1) six weeks of PEP plus manual auricular acupuncture; 2) six weeks of PEP alone. Both groups will also complete a further six weeks of self-paced exercise with telephone follow-up support. In addition to a baseline and exit questionnaire at the beginning and end of the study, the following outcomes will be collected at baseline, and after 7, 13 and 25 weeks: pain frequency and bothersomeness, back-specific function, objective assessment and recall of physical activity, use of analgesia, perceived self-efficacy, fear avoidance beliefs, and beliefs about the consequences of back pain. Since this is a feasibility study, significance tests will not be presented, and treatment effects will be represented by point estimates and confidence intervals. For each outcome variable, analysis of covariance will be performed on the data, conditioning on the baseline value. Discussion The results of this study investigating the adjuvant effects of auricular acupuncture to exercise in managing CLBP will be used to inform the design of a future multi-centre randomised controlled trial. Trial Registration Current Controlled Trials ISRCTN94142364

Exercise and manual auricular acupuncture: a pilot assessor-blind randomised controlled trial. (The acupuncture and personalised exercise programme (APEP) Trial)

<p>Abstract</p> <p>Background</p> <p>Evidence supports the use of exercise for chronic low back pain (CLBP); however, adherence is often poor due to ongoing pain. Auricular acupuncture is a form of pain relief involving the stimulation of points on the outer ear corresponding with specific body parts. It may be a useful adjunct to exercise in managing CLBP; however, there is only limited evidence to support its use with this patient group.</p> <p>Methods/Design</p> <p>This study was designed to test the feasibility of an assessor-blind randomised controlled trial which assess the effects on clinical outcomes and exercise adherence of adding manual auricular acupuncture to a personalised and supervised exercise programme (PEP) for CLBP. No sample size calculation has been carried out as this study aims to identify CLBP referral rates within the catchment area of the study site. The researchers aim to recruit four cohorts of n = 20 participants to facilitate a power analysis for a future randomised controlled trial. A computer generated random allocation sequence will be prepared centrally and used to allocate participants by cohort to one of the following interventions: 1) six weeks of PEP <it>plus </it>manual auricular acupuncture; 2) six weeks of PEP alone. Both groups will also complete a further six weeks of self-paced exercise with telephone follow-up support. In addition to a baseline and exit questionnaire at the beginning and end of the study, the following outcomes will be collected at baseline, and after 7, 13 and 25 weeks: pain frequency and bothersomeness, back-specific function, objective assessment and recall of physical activity, use of analgesia, perceived self-efficacy, fear avoidance beliefs, and beliefs about the consequences of back pain. Since this is a feasibility study, significance tests will not be presented, and treatment effects will be represented by point estimates and confidence intervals. For each outcome variable, analysis of covariance will be performed on the data, conditioning on the baseline value.</p> <p>Discussion</p> <p>The results of this study investigating the adjuvant effects of auricular acupuncture to exercise in managing CLBP will be used to inform the design of a future multi-centre randomised controlled trial.</p> <p>Trial Registration</p> <p>Current Controlled Trials ISRCTN94142364.</p

Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur? Can the dates be regarded as real ages, reflecting several growth episodes? Furthermore, under some circumstances of (ultra-)high-temperature metamorphism, decoupling of zircon U–Pb dates from their trace element geochemistry has been reported. Understanding these processes is crucial to help interpret such dates in the context of the P–T history. Our study presents evidence for decoupling in zircon from the highest grade metapelites (> 850 °C) taken along a continuous high-temperature metamorphic field gradient in the Ivrea Zone (NW Italy). These rocks represent a well-characterised segment of Permian lower continental crust with a protracted high-temperature history. Cathodoluminescence images reveal that zircons in the mid-amphibolite facies preserve mainly detrital cores with narrow overgrowths. In the upper amphibolite and granulite facies, preserved detrital cores decrease and metamorphic zircon increases in quantity. Across all samples we document a sequence of four rim generations based on textures. U–Pb dates, Th/U ratios and Ti-in-zircon concentrations show an essentially continuous evolution with increasing metamorphic grade, except in the samples from the granulite facies, which display significant scatter in age and chemistry. We associate the observed decoupling of zircon systematics in high-grade non-metamict zircon with disturbance processes related to differences in behaviour of non-formula elements (i.e. Pb, Th, U, Ti) at high-temperature conditions, notably differences in compatibility within the crystal structure

The Terminal Immunoglobulin-Like Repeats of LigA and LigB of Leptospira Enhance Their Binding to Gelatin Binding Domain of Fibronectin and Host Cells

Leptospira spp. are pathogenic spirochetes that cause the zoonotic disease leptospirosis. Leptospiral immunoglobulin (Ig)-like protein B (LigB) contributes to the binding of Leptospira to extracellular matrix proteins such as fibronectin, fibrinogen, laminin, elastin, tropoelastin and collagen. A high-affinity Fn-binding region of LigB has been localized to LigBCen2, which contains the partial 11th and full 12th Ig-like repeats (LigBCen2R) and 47 amino acids of the non-repeat region (LigBCen2NR) of LigB. In this study, the gelatin binding domain of fibronectin was shown to interact with LigBCen2R (KD = 1.91±0.40 µM). Not only LigBCen2R but also other Ig-like domains of Lig proteins including LigAVar7'-8, LigAVar10, LigAVar11, LigAVar12, LigAVar13, LigBCen7'-8, and LigBCen9 bind to GBD. Interestingly, a large gain in affinity was achieved through an avidity effect, with the terminal domains, 13th (LigA) or 12th (LigB) Ig-like repeat of Lig protein (LigAVar7'-13 and LigBCen7'-12) enhancing binding affinity approximately 51 and 28 fold, respectively, compared to recombinant proteins without this terminal repeat. In addition, the inhibited effect on MDCKs cells can also be promoted by Lig proteins with terminal domains, but these two domains are not required for gelatin binding domain binding and cell adhesion. Interestingly, Lig proteins with the terminal domains could form compact structures with a round shape mediated by multidomain interaction. This is the first report about the interaction of gelatin binding domain of Fn and Lig proteins and provides an example of Lig-gelatin binding domain binding mediating bacterial-host interaction

Phagosomal Rupture by Mycobacterium tuberculosis Results in Toxicity and Host Cell Death

Survival within macrophages is a central feature of Mycobacterium tuberculosis pathogenesis. Despite significant advances in identifying new immunological parameters associated with mycobacterial disease, some basic questions on the intracellular fate of the causative agent of human tuberculosis in antigen-presenting cells are still under debate. To get novel insights into this matter, we used a single-cell fluorescence resonance energy transfer (FRET)-based method to investigate the potential cytosolic access of M. tuberculosis and the resulting cellular consequences in an unbiased, quantitative way. Analysis of thousands of THP-1 macrophages infected with selected wild-type or mutant strains of the M. tuberculosis complex unambiguously showed that M. tuberculosis induced a change in the FRET signal after 3 to 4 days of infection, indicating phagolysosomal rupture and cytosolic access. These effects were not seen for the strains M. tuberculosisΔRD1 or BCG, both lacking the ESX-1 secreted protein ESAT-6, which reportedly shows membrane-lysing properties. Complementation of these strains with the ESX-1 secretion system of M. tuberculosis restored the ability to cause phagolysosomal rupture. In addition, control experiments with the fish pathogen Mycobacterium marinum showed phagolysosomal translocation only for ESX-1 intact strains, further validating our experimental approach. Most importantly, for M. tuberculosis as well as for M. marinum we observed that phagolysosomal rupture was followed by necrotic cell death of the infected macrophages, whereas ESX-1 deletion- or truncation-mutants that remained enclosed within phagolysosomal compartments did not induce such cytotoxicity. Hence, we provide a novel mechanism how ESX-1 competent, virulent M. tuberculosis and M. marinum strains induce host cell death and thereby escape innate host defenses and favor their spread to new cells. In this respect, our results also open new research directions in relation with the extracellular localization of M. tuberculosis inside necrotic lesions that can now be tackled from a completely new perspective

Pulmonary oxygen uptake and muscle deoxygenation kinetics during recovery in trained and untrained male adolescents

Previous studies have demonstrated faster pulmonary oxygen uptake ( V ˙ O 2 ) kinetics in the trained state during the transition to and from moderate-intensity exercise in adults. Whilst a similar effect of training status has previously been observed during the on-transition in adolescents, whether this is also observed during recovery from exercise is presently unknown. The aim of the present study was therefore to examine V ˙ O 2 kinetics in trained and untrained male adolescents during recovery from moderate-intensity exercise. 15 trained (15 ± 0.8 years, V ˙ O 2max 54.9 ± 6.4 mL kg−1 min−1) and 8 untrained (15 ± 0.5 years, V ˙ O 2max 44.0 ± 4.6 mL kg−1 min−1) male adolescents performed two 6-min exercise off-transitions to 10 W from a preceding “baseline” of exercise at a workload equivalent to 80% lactate threshold; V ˙ O 2 (breath-by-breath) and muscle deoxyhaemoglobin (near-infrared spectroscopy) were measured continuously. The time constant of the fundamental phase of V ˙ O 2 off-kinetics was not different between trained and untrained (trained 27.8 ± 5.9 s vs. untrained 28.9 ± 7.6 s, P = 0.71). However, the time constant (trained 17.0 ± 7.5 s vs. untrained 32 ± 11 s, P < 0.01) and mean response time (trained 24.2 ± 9.2 s vs. untrained 34 ± 13 s, P = 0.05) of muscle deoxyhaemoglobin off-kinetics was faster in the trained subjects compared to the untrained subjects. V ˙ O 2 kinetics was unaffected by training status; the faster muscle deoxyhaemoglobin kinetics in the trained subjects thus indicates slower blood flow kinetics during recovery from exercise compared to the untrained subjects

The Back 2 Activity Trial: education and advice versus education and advice plus a structured walking programme for chronic low back pain

<p>Abstract</p> <p>Background</p> <p>Current evidence supports the use of exercise-based treatment for chronic low back pain that encourages the patient to assume an active role in their recovery. Walking has been shown it to be an acceptable type of exercise with a low risk of injury. However, it is not known whether structured physical activity programmes are any more effective than giving advice to remain active.</p> <p>Methods/Design</p> <p>The proposed study will test the feasibility of using a pedometer-driven walking programme, as an adjunct to a standard education and advice session in participants with chronic low back pain. Fifty adult participants will be recruited via a number of different sources. Baseline outcome measures including self reported function; objective physical activity levels; fear-avoidance beliefs and health-related quality of life will be recorded. Eligible participants will be randomly allocated under strict, double blind conditions to one of two treatments groups. Participants in group A will receive a single education and advice session with a physiotherapist based on the content of the 'Back Book'. Participants in group B will receive the same education and advice session. In addition, they will also receive a graded pedometer-driven walking programme prescribed by the physiotherapist. Follow up outcomes will be recorded by the same researcher, who will remain blinded to group allocation, at eight weeks and six months post randomisation. A qualitative exploration of participants' perception of walking will also be examined by use of focus groups at the end of the intervention. As a feasibility study, treatment effects will be represented by point estimates and confidence intervals. The assessment of participant satisfaction will be tabulated, as will adherence levels and any recorded difficulties or adverse events experienced by the participants or therapists. This information will be used to modify the planned interventions to be used in a larger randomised controlled trial.</p> <p>Discussion</p> <p>This paper describes the rationale and design of a study which will test the feasibility of using a structured, pedometer-driven walking programme in participants with chronic low back pain.</p> <p>Trial Registration</p> <p>[ISRCTN67030896]</p