556 research outputs found

    High-Resolution Measurements of the Dark Matter Halo of NGC 2976: Evidence for a Shallow Density Profile

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    We have obtained two-dimensional velocity fields of the dwarf spiral galaxy NGC 2976 in Halpha and CO. The high spatial (~75 pc) and spectral (13 km/s and 2 km/s, respectively) resolution of these observations, along with our multicolor optical and near-infrared imaging, allow us to measure the shape of the density profile of the dark matter halo with good precision. We find that the total (baryonic plus dark matter) mass distribution of NGC 2976 follows a rho_tot ~ r^(-0.27 +/- 0.09) power law out to a radius of 1.8 kpc, assuming that the observed radial motions provide no support. The density profile attributed to the dark halo is even shallower, consistent with a nearly constant density of dark matter over the entire observed region. A maximal disk fit yields an upper limit to the K-band stellar mass-to-light ratio (M*/L_K) of 0.09^{+0.15}_{-0.08} M_sun/L_sun,K (including systematic uncertainties), with the caveat that for M*/L_K > 0.19 M_sun/L_sun,K the dark matter density increases with radius, which is unphysical. Assuming 0.10 M_sun/L_sun,K < M*/L_K < 0.19 M_sun/L_sun,K, the dark matter density profile lies between rho_dm ~ r^-0.17 and rho_dm ~ r^-0.01. Therefore, independent of any assumptions about the stellar disk or the functional form of the density profile, NGC 2976 does not contain a cuspy dark matter halo. We also investigate some of the systematic effects that can hamper rotation curve studies, and show that 1) longslit rotation curves are far more vulnerable to systematic errors than two-dimensional velocity fields, 2) NGC 2976 contains large radial motions at small radii, and 3) the Halpha and CO velocity fields of NGC 2976 agree within their uncertainties. [slightly abridged]Comment: 30 pages, 4 tables, 13 figures (7 in color; Figures 1 and 3 are low-resolution to save space). Accepted for publication in ApJ. Version with full-resolution figures available at http://astro.berkeley.edu/~bolatto/ngc2976rotation.ps (46 MB

    X ray absorption spectroscopy and X ray Raman scattering of water and ice; an experimental view

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    Here we present a review of X-ray absorption spectroscopy and X-ray Raman scattering with the perspective to understand the spectra of water including changes with temperature, mass of the water molecule and presence of monovalent ions. The different detection schemes are discussed and it is concluded that transmission X-ray absorption measurements, using a small area where the thickness is uniform, and X-ray Raman scattering give the most reliable spectra. Different model systems are discussed such as the surface and bulk of ice and various adsorbed monolayer structures on metal surfaces.</p

    Similar promotion of Aβ(1-42 )fibrillogenesis by native apolipoprotein E ε3 and ε4 isoforms

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    The apolipoprotein E ε4 allele contributes to the genetic susceptibility underlying a large proportion (~40–60%) of typical, sporadic Alzheimer disease. Apolipoprotein E deficient mice made transgenic for human apolipoprotein E ε4 accumulate excess cerebral amyloid when compared to similarly prepared mice expressing human apolipoprotein E ε3. Therefore, it is important to search for relevant interactions(s) between apolipoprotein E ε4 and Aβ in order to clarify the biological role for apolipoprotein E ε4 in Alzheimer disease. Using a thioflavine T (ThT)-based assay, we have investigated the effects of native human apolipoprotein E isoforms on the kinetics of Aβ fibrillogenesis. No obvious profibrillogenic activity was detected in Aβ(1-40)-based assays of any native apolipoprotein E isoform. However, when ThT assays were repeated using Aβ(1-42), modest, but statistically significant, profibrillogenic activity was detected in both apolipoprotein E ε3- and apolipoprotein E ε4-containing media and was similar in magnitude for the two isoforms. These data demonstrate that native apolipoprotein E possesses "pathological chaperone"-type activity for Aβ: in other words, the data indicate that a chaperone-like misfolding reaction can occur between native apolipoprotein E and Aβ. However, the equipotent activities of the apolipoprotein E ε3 and ε4 isoforms suggests the possibility that either extended co-incubation of apolipoprotein E and Aβ, or, perhaps, the inclusion in the reaction of other fibrillogenesis-modulation co-factors (such as metal ions, or inflammatory mediators such as reactive oxygen species, α(2)-macroglobulin, apolipoprotein J, etc.) may be required for modeling in vitro the apolipoprotein E-isoform-specific-regulation of extracellular Aβ accumulation that occurs in vivo. Alternatively, other events, such as differential apolipoprotein E-isoform-mediated clearance of Aβ or of apolipoprotein E/Aβ complexes may underlie apolipoprotein E-isoform-dependent Aβ accumulation

    Task-sharing and telemedicine delivery of psychotherapy to treat perinatal depression: a pragmatic, noninferiority randomized trial

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    Task-sharing and telemedicine can increase access to effective psychotherapies. Scaling Up Maternal Mental healthcare by Increasing access to Treatment (SUMMIT) is pragmatic, multisite, noninferiority, four-arm trial that tested the non-inferiority of provider (non-specialist vs. specialist providers) and modality (telemedicine vs. in-person) in delivering psychotherapy for perinatal depressive symptoms. Across three university-affiliated networks in the United States and Canada, pregnant and postpartum adult participants were randomized 1:1:1:1 to each arm (472 nonspecialist telemedicine, 145 nonspecialist in-person, 469 specialist telemedicine and 144 specialist in-person) and offered weekly behavioral activation treatment sessions. The primary outcome was depressive symptoms (Edinburgh Postnatal Depression Scale (EPDS)) and the secondary outcome was anxiety (Generalized Anxiety Disorder (GAD-7)) symptoms at 3 months post-randomization. Between 8 January 2020 and 4 October 2023, 1,230 participants were recruited. Noninferiority was met for the primary outcome comparing provider (EPDS: nonspecialist 9.27 (95% CI 8.85–9.70) versus specialist 8.91 (95% CI 8.49–9.33)) and modality (EPDS: telemedicine 9.15 (95% CI 8.79–9.50) versus in-person 8.92 (95% CI 8.39–9.45)) for both intention-to-treat and per protocol analyses. Noninferiority was also met for anxiety symptoms in both comparisons. There were no serious or adverse events related to the trial. This trial suggests compelling evidence for task-sharing and telemedicine to improve access to psychotherapies for perinatal depressive and anxiety symptoms. ClinicalTrials.gov NCT0415386

    Optimizing treatment for depression in primary care using psychotherapy versus antidepressant medication in a low-resource setting: protocol for the OptimizeD randomized controlled trial

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    Background: Psychotherapy and antidepressant medications are first-line treatments for depression, and they both have significant treatment effects on average. However, treatment response varies widely across patients, and neither approach is universally effective. Identifying the most effective treatment for each patient is critical everywhere, but particularly in low-resource settings where access to mental health care is limited. The Optimizing Depression (OptimizeD) trial aims to explore whether different patients respond differently to behavioral activation therapy versus antidepressant medication and if providing each patient with their optimal treatment improves outcomes in primary care. Methods: We plan to randomize 1,500 patients with moderate to severe depression (defined as a Patient Health Questionnaire [PHQ-9] score ≥ 10) from primary healthcare settings in Bhopal, India, with equal allocation either to a culturally adapted behavioral activation therapy delivered by trained counselors (Healthy Activity Program) or to antidepressant medication (fluoxetine). Treatment will last 3 months, with remission (defined as PHQ-9 score < 5) at 3 months as the primary endpoint. Using machine learning, we will attempt to develop a precision treatment rule that leverages baseline clinical, psychological, cognitive, socioeconomic, and biological data to predict which treatment is most likely to achieve remission for each patient. Cost-effectiveness analysis will then assess whether the added costs of optimizing treatment are justified by improvements in remission, recovery, and cost savings at the health system and societal levels. Secondary and exploratory objectives include assessing the effectiveness of optimization in a range of secondary outcomes, evaluating treatment mechanisms, and exploring whether incorporating genetic and biological markers as predictors improves treatment optimization. Discussion: The OptimizeD trial will evaluate whether baseline information collected in routine care can inform optimal depression treatment selection and identify predictors of nonresponse to facilitate timely specialist referrals. Findings have the potential to enhance personalized depression care in primary health systems, particularly in low-resource settings, with broader implications for global public health. Trial registration: ClinicalTrials.gov (NCT05944926; registered July 2, 2023) and Clinical Trials Registry India (CTRI/2024/01/061932; registered January 29, 2024)

    Systematic review and meta-analysis of Transurethral Needle Ablation in symptomatic Benign Prostatic Hyperplasia

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    BACKGROUND: Benign prostatic hyperplasia (BPH) constitutes a major clinical problem. Minimally invasive therapies for the treatment of symptomatic BPH include Transurethral Needle Ablation (TUNA), but it is unclear what impact this technique has on the disease and its role among other currently available therapeutic options. The objective of this study is to ascertain the efficacy and safety of TUNA in the treatment of BPH. METHODS: Systematic review of the literature until January 2005 and meta-analysis of clinical studies assessing TUNA in symptomatic BPH. Studies were critically appraised. Estimates of effect were calculated according to the random-effects model. RESULTS: 35 studies (9 comparative, 26 non-comparative) were included. Although evidence was limited by methodological issues, the analysis of relevant outcomes indicates that while TUNA significantly improves BPH parameters with respect to baseline, it does not reach the same level of efficacy as TURP in respect to all subjective and objective variables. Further, its efficacy declines in the long-term with a rate of secondary-treatment significantly higher than of TURP [OR: 7.44 (2.47, 22.43)]. Conversely, TUNA seems to be a relatively safe technique and shows a lower rate of complications than TURP [OR:0.14 (0.05, 0.14)] with differences being particularly noteworthy in terms of postoperative bleeding and sexual disorders. Likewise, TUNA has fewer anesthetic requirements and generates a shorter hospital stay than TURP [WMD: -1.9 days (-2.75, -1.05)]. Scarce data and lack of replication of comparisons hinder the assessment of TUNA vs. other local therapies. No comparisons with medical treatment were found. CONCLUSION: The body of evidence on which TUNA has been introduced into clinical practice is of only moderate-low quality. Available evidence suggest that TUNA is a relatively effective and safe technique that may eventually prove to have a role in selected patients with symptomatic BPH. TUNA significantly improves BPH parameters with respect to baseline values, but it does not reach the same level of efficacy and long-lasting success as TURP. On the other hand, TUNA seems to be superior to TURP in terms of associated morbidity, anesthetic requirements and length of hospital stay. With respect to the role of TUNA vis-à-vis other minimally invasive therapies, the results of this review indicate that there are insufficient data to define this with any degree of accuracy. Overall cost-effectiveness and the role of TUNA versus medical treatment need further evaluation

    Conversion of Vertical Banded Gastroplasty to Roux-en-Y Gastric Bypass Results in Restoration of the Positive Effect on Weight Loss and Co-morbidities: Evaluation of 101 Patients

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    BACKGROUND: Vertical banded gastroplasty (VBG) is a widely used restrictive procedure in bariatric surgery. However, the re-operation rate after this operation is high. In the case of VBG failure, a conversion to Roux-en-Y gastric bypass (RYGBP) is an option. A study was undertaken to evaluate the results of the conversion from VBG to RYGBP. METHODS: 101 patients had conversion from VBG to RYGBP. Patients were separated into 3 groups, based on the indication for conversion: weight regain (group 1), excessive weight loss (group 2) and severe eating difficulties (group 3). Data for the study were collected by retrospective analysis of prospectively recorded data. RESULTS: Weight regain (group 1) was the reason for conversion in 73.3% of patients. Staple-line disruption was the most important cause for the weight regain (74.3%). Excessive weight loss (group 2) affected 14% of patients and was caused by outlet stenosis in 78.6% of patients. The remaining 13% had severe eating difficulties as a result of outlet stenosis (46.1%), pouch dilatation (30.8%) and pouch diverticula (23.1%). Mean BMI before conversion to RYGBP was 40.5, 22.3 and 29.8 kg/m2 in group 1, 2 and 3, respectively. Minor or major direct postoperative complications were observed in 2.0% to 7.0%. Long-term complications were more frequent, and consisted mainly of anastomotic stenosis (22.7%) and incisional hernia (16.8%). Follow-up after conversion was achieved in all patients (100%), with a mean period of 38 +/- 29 months. BMI decreased from 40.5 to 30.1 kg/m2, increased from 22.3 to 25.3 kg/m2. and decreased slightly from 29.8 to 29.0 kg/m2 in group 1, 2 and 3, respectively. All patients in group 3 noticed an improvement in eating difficulties. CONCLUSION: Complications after conversion from failed VBG to RYGBP are substantial and need to be considered. However, the conversion itself is a successful operation in terms of effect on body weight and treating eating difficulties after VBG
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