Bifurcation of Localized Disturbances in a Model Biochemical Reaction

Asymptotic solutions are presented to the nonlinear parabolic reaction-diffusion equations describing a model biochemical reaction proposed by I. Prigogine. There is a uniform steady state which, for certain values of the adjustable parameters, may be unstable. When the uniform solution is slightly unstable, the two-timing method is used to find the bifurcation of new solutions of small amplitude. These may be either nonuniform steady states or time-periodic solutions, depending on the ratio of the diffusion coefficients. When one of the parameters is allowed to depend on space and the basic state is unstable, it is found that the nonuniform steady state which is approached may show localized spatial oscillations. The localization arises out of the presence of turning points in the linearized stability equations

CD5 Plays an Inhibitory Role in the Suppressive Function of Murine CD4\u3csup\u3e+\u3c/sup\u3e CD25\u3csup\u3e+\u3c/sup\u3e T\u3csub\u3ereg\u3c/sub\u3e Cells

A subset of CD4+ T cells, the CD4+ CD25+ regulatory T (Treg) cells in the lymphoid organs and peripheral blood are known to possess suppressive function. Previous in vitro and in vivo studies have indicated that T cell receptor (TCR) signal is required for development of such ‘natural regulatory (Treg) cells’ and for activation of the effector function of CD4+ CD25+ regulatory T cells. CD5 is a cell surface molecule present on all T cells and a subtype of B lymphocytes, the B-1 cells, primarily localized to coelomic cavities, Peyer\u27s patches, tonsils and spleen. CD5 acts as a negative regulator of T cell and B cell signaling via recruitment of SHP-1. Here, we demonstrate that Treg cells obtained from CD5−/− mice are more potent than those from wild type mice in suppressing the in vitro cell proliferation of anti-CD3 stimulated CD4+ CD25− responder T cells. This phenomenon was cell contact and GITR dependent. Lack of CD5 expression on Treg cells (from spleen, lymph node and thymus) did not affect the intracellular levels of Foxp3. However, CD5−/− Tregthymocytes were able to elicit a higher Ca2+ response to TCR + co-stimulatory signals than the wild type cells. CD5−/− mice expressed more Foxp3 mRNA in the colon than wild type mice, and additionally, the severity of the dextran sulfate sodium (DSS)-induced colitis in CD5−/− mice was less than the wild type strain. We suggest that manipulation of CD5 expression or the downstream signaling components of CD4+ CD25+ Treg cells as a potential strategy for therapeutic intervention in cases of auto-immune disorders

Differences in Complication Rates Between Roux-en-Y Gastric Bypass and Longitudinal Sleeve Gastrectomy

Introduction: Sleeve Gastrectomy (SG) has surpassed Roux-en-Y Gastric Bypass (RYGB) as the most commonly performed bariatric operation. Though the beneficial effect of SG on Type 2 Diabetes Mellitus is less than that of RYGB, it is perceived to have a lower complication rate. The purpose of this study was to quantify the complication rates between of SG and RYGB in a severely obese diabetic population. Methods: This was a retrospective cohort study that included all diabetic patients undergoing RYGB and SG at an academic medical center from January 1, 2011 to July 1, 2015. Patients were followed at 6 week, 6 month, 1 year, 2 year, and 3 year postoperatively. Outpatient and emergency visits were identified in the EMR system. Continuous data was analyzed using Student T tests and discrete data was analyzed using Fisher’s Exact Test. We defined early complications as those occurring within 30 days postoperatively, and late complications as those after 30 days. Results: A total of 96 patients underwent RYGB and 89 underwent SG. The groups were concurrent and similar with regards to preoperative demographic factors such as age, gender, Hgb-A1c, HOMA2 parameters, excess body weight, BMI, and diabetic medication use. In terms of early complications, the rate of hemorrhage requiring transfusion was higher in the SG group compared to RYGB (10.1% vs. 3.1%, p=0.073). Postoperative length of stay was lower in the SG group (m=1.7 d vs. m=2 d, p=0.02), but the early readmission rate was also higher in the SG group (7.9% vs. 2.1%, p=0.09). For late postoperative complications, there were 4 anastomotic ulcer perforations and one case of internal hernia in the RYGB group. There were 6 late postoperative reoperations in the RYGB group (6% vs. 0%, p=0.03). In addition, 13 patients underwent 16 total upper endoscopies in the RYGB group (13.5% vs. 0%, p=0.0002). The cumulative rate of early and late interventions was higher in the RYGB group (20% vs. 3.4%, p=0.0005). Conclusions: While the rate of early postoperative complication is similar between SG and RYGB, the need for late intervention is higher after RYGB. The cumulative need for reintervention (early and late) is higher after RYGB. This may explain the shift from Roux-en-Y Gastric Bypass to Sleeve Gastrectomy as the most commonly performed bariatric intervention

Radio astronomy

The following subject areas are covered: (1) scientific opportunities (millimeter and sub-millimeter wavelength astronomy; meter to hectometer astronomy; the Sun, stars, pulsars, interstellar masers, and extrasolar planets; the planets, asteroids, and comets; radio galaxies, quasars, and cosmology; and challenges for radio astronomy in the 1990's); (2) recommendations for new facilities (the millimeter arrays, medium scale instruments, and small-scale projects); (3) continuing activities and maintenance, upgrading of telescopes and instrumentation; (4) long range programs and technology development; and (5) social, political, and organizational considerations

Comparison of Diabetic Remission Rates following Roux en-Y Gastric Bypass and Longitudinal Sleeve Gastrectomy

Introduction: Bariatric surgery is being increasingly investigated as treatment for Type II Diabetes Mellitus (T2DM). As Sleeve Gastrectomy (SG) surpasses Roux-en-Y Gastric Bypass (RYGB) as the new standard in bariatric surgery, it is still unknown if its efficacy in achieving remission is comparable to RYGB. This study compared diabetic remission rates between SG and RYGB in order to identify the predictive factors for remission and the mechanisms of achieving remission. Methods: This was a retrospective cohort study comparing all diabetic patients undergoing RYGB and SG at an academic medical center from 1/1/11-7/1/15. Patients were followed preoperatively and at 6 week, 6 month, and 1, 2, and 3 year intervals. We defined diabetic remission as HbA1c under 7 without insulin or hypoglycemic use and excess body weight (EBW) as percent over ideal body weight. Data were analyzed using Cox analysis, Fisher’s Exact Tests, and Student T Tests. Results: During the study, 96 patients underwent RYGB and 89 underwent SG. Preoperatively, patients from both groups had similar age, weight, gender, preoperative weight loss, HbA1c at onset and at surgery, oral hypoglycemic use, insulin use, and HOMA2 parameters. At one year postoperatively, patients who underwent RYGB showed a statistically greater postoperative EBW loss (62% vs. 36% p \u3c 0.0001). Kaplan Meier analysis showed a significantly higher rate of remission, (83% vs. 66%) in patients who underwent SG (p=0.02). After using Cox analysis to account for differences in delta BMI (p=0.04), EBW loss (p=0.04), preoperative HOMA2 parameters (p=0.008-0.011), and preoperative factors such as HbA1c and insulin use (p=0.001 for both), there was no change in RYGB’s impact on diabetic remission compared to SG. Conclusion: Our results confirm that RYGB achieves a significantly greater rate of diabetic remission and a significantly higher weight loss than SG. Additionally, the difference in rate of diabetic remission is not explained by weight loss or preoperative predictors of less reversible diabetes (HOMA2 parameters, use of insulin). Identification of the factor(s) responsible for this differential effect on diabetes may afford opportunity for therapeutic intervention

Current posttraumatic stress disorder and exaggerated threat sensitivity associated with elevated inflammation in the Mind Your Heart Study

OBJECTIVE: Elevated inflammation has been repeatedly observed in posttraumatic stress disorder (PTSD), and it may drive the development of both psychiatric symptoms and physical comorbidities. However, it is not clear if elevated inflammation is a feature of both remitted and current PTSD, and little is known about relationships between specific clusters of PTSD symptoms and inflammation. Exaggerated threat sensitivity, as indexed by threat reactivity and avoidance of perceived threats, may be particularly closely associated with inflammation. METHODS: We assessed PTSD symptoms and threat sensitivity using the Clinician Administered PTSD Scale in 735 Veterans Affairs patients (35% current PTSD; 16% remitted PTSD) who participated in the Mind Your Heart Study (mean age=59±11; 94% male). High sensitivity C-reactive protein (hsCRP), white blood cell count (WBC), and fibrinogen were used as indices of inflammation. Analysis of covariance models with planned contrasts were used to examine differences in inflammation by PTSD status, adjusting for age, sex, race, kidney function and socioeconomic status

A multi-object fiber spectrograph for The Hale Telescope

A new faint-object spectrograph has been designed around the capabilities of fiber optics. This instrument, the Norris Spectrograph, is for exclusive use at the Cassegrain focus (f/16) of The Hale Telescope and is optimized for faint galaxy spectroscopy. There are 176 independently positionable fibers that are serially manipulated by a single robotic system. Each of these fibers sees 1.6 arcsec on the sky and the total positionable area is in excess of 300 arcmin^2. Unlike most multiobject spectrographs which utilize fibers that are several tens of meters long, the philosophy of the design of the Norris was quite the antithesis, i.e., to minimize the fiber lengths; hence, it is an entirely self-contained telescope-mounted instrument for the Cassegrain focus. The instrument consists of an integrated xy stage, for the fiber positioning, and an attached optical spectrograph. The design of the spectrograph is basically classical: spherical collimator mirror, standard reflection grating, and a newly designed all-transmissive-optics camera lens. The detector currently used is a thinned, AR-coated 2048 X 2048 Tektronix CCD. Fibers are arranged in two linear opposing banks that can access the 20 arcmin diameter field-of-view (FOV) of the instrument. The accuracy of fiber placement (assuming errorless coordinates) is less than 0.1 arcsec over the entire FOV. Fibers may be placed as close as 16 arcsec. This permits close pairings of fibers for very faint-object spectroscopy. Beam switching between paired fibers, as was done with two-channel spectrographs of yesteryear, will help average out temporal and spatial variations of the light of the night sky. Actual observations performed in this mode of operation indicate that the quality of the sky subtraction improves, as would be expected. The density of paired fibers within the Norris FOV matches the approximate density of faint field galaxies expected to a blue magnitude of 21. Software exists to take object lists (α,δ) and convert them to rectilinear (x,y) values (mm) on the xy stage by gnomonic projection and to assign fibers. This software also corrects for precession of the equinoxes, proper motion if epoch differences exist, and corrects for differential atmospheric refraction. To place a single fiber takes approximately 5 s on the average. A lower limit to the efficiency of the spectrograph plus telescope has been estimated to be 6.8% at 5500 Å. In order to derive the throughput of the instrument, the efficiency of the telescope, estimated to be approximately 56%, must be divided out. This value is consistent with the expectation that the reduction in efficiency from that of a standard CCD spectrograph such as The Hale Telescope's Double Spectrograph will be about a factor of 2. This results from the 60%-70% transmittance of the fibers and other losses. The spectra produced are linear with little distortion. With 10 A spectral resolution, fitting residuals on the order of 100 km s^(-1) are easily obtainable by modeling the dispersion by a third-order polynomial. The resolutions currently available range from 1 to about 20 Å. The spectra have a FWHM in the direction perpendicular to that of the dispersion of about 90 µm, or equivalently about three 27 pixels found in the older Tektronix 2048 CCDs. The interorder spacing of 250 µm is large enough to permit clean spectrum extractions. The instrument has been in use for several years. The scientific programs vary from high resolution (1 Å resolution) spectroscopy of stars in nearby globular clusters to a low spectral resolution (10 Å) survey of faint field galaxies. In this latter survey, with typical 2-hr exposures, absorption-line redshifts as high as z ~ 0.5 have been routinely measured. Several heretofore unknown quasars with redshifts around three have also been discovered serendipitously

Chemical data assimilation estimates of continental U.S. ozone and nitrogen budgets during the Intercontinental Chemical Transport Experiment-North America

Global ozone analyses, based on assimilation of stratospheric profile and ozone column measurements, and NOy predictions from the Real-time Air Quality Modeling System (RAQMS) are used to estimate the ozone and NOy budget over the continental United States during the July-August 2004 Intercontinental Chemical Transport Experiment-North America (INTEX-A). Comparison with aircraft, satellite, surface, and ozonesonde measurements collected during INTEX-A show that RAQMS captures the main features of the global and continental U.S. distribution of tropospheric ozone, carbon monoxide, and NOy with reasonable fidelity. Assimilation of stratospheric profile and column ozone measurements is shown to have a positive impact on the RAQMS upper tropospheric/lower stratosphere ozone analyses, particularly during the period when SAGE III limb scattering measurements were available. Eulerian ozone and NOy budgets during INTEX-A show that the majority of the continental U.S. export occurs in the upper troposphere/lower stratosphere poleward of the tropopause break, a consequence of convergence of tropospheric and stratospheric air in this region. Continental U.S. photochemically produced ozone was found to be a minor component of the total ozone export, which was dominated by stratospheric ozone during INTEX-A. The unusually low photochemical ozone export is attributed to anomalously cold surface temperatures during the latter half of the INTEX-A mission, which resulted in net ozone loss during the first 2 weeks of August. Eulerian NOy budgets are shown to be very consistent with previously published estimates. The NOy export efficiency was estimated to be 24%, with NOx + PAN accounting for 54% of the total NOy export during INTEX-A. Copyright 2007 by the American Geophysical Union

Validation of the UCLA Child Post traumatic stress disorder-reaction index in Zambia

<p>Abstract</p> <p>Background</p> <p>Sexual violence against children is a major global health and human rights problem. In order to address this issue there needs to be a better understanding of the issue and the consequences. One major challenge in accomplishing this goal has been a lack of validated child mental health assessments in low-resource countries where the prevalence of sexual violence is high. This paper presents results from a validation study of a trauma-focused mental health assessment tool - the UCLA Post-traumatic Stress Disorder - Reaction Index (PTSD-RI) in Zambia.</p> <p>Methods</p> <p>The PTSD-RI was adapted through the addition of locally relevant items and validated using local responses to three cross-cultural criterion validity questions. Reliability of the symptoms scale was assessed using Cronbach alpha analyses. Discriminant validity was assessed comparing mean scale scores of cases and non-cases. Concurrent validity was assessed comparing mean scale scores to a traumatic experience index. Sensitivity and specificity analyses were run using receiver operating curves.</p> <p>Results</p> <p>Analysis of data from 352 youth attending a clinic specializing in sexual abuse showed that this adapted PTSD-RI demonstrated good reliability, with Cronbach alpha scores greater than .90 on all the evaluated scales. The symptom scales were able to statistically significantly discriminate between locally identified cases and non-cases, and higher symptom scale scores were associated with increased numbers of trauma exposures which is an indication of concurrent validity. Sensitivity and specificity analyses resulted in an adequate area under the curve, indicating that this tool was appropriate for case definition.</p> <p>Conclusions</p> <p>This study has shown that validating mental health assessment tools in a low-resource country is feasible, and that by taking the time to adapt a measure to the local context, a useful and valid Zambian version of the PTSD-RI was developed to detect traumatic stress among youth. This valid tool can now be used to appropriately measure treatment effectiveness, and more effectively and efficiently triage youth to appropriate services.</p