Spatial variations of teleseismic P-wave attenuation and scattering beneath the southeastern United States and the Malawi and Luangwa rift zones in East Africa

Seismic attenuation is an important physical parameter for characterizing subsurface morphology and the thermal structure of the Earth’s crust and mantle. In this study, teleseismic P-wave amplitude spectra are used to examine the seismic attenuation beneath the southeastern United States and the Malawi and Luangwa rift zones in east African. The resulting seismic attenuation parameters (Δt*) reveal a systematic contrast between the Appalachian Mountains and the Gulf of Mexico Coastal Plain exhibiting high and low attenuation, respectively. Spatial coherency analysis of the Δt* observations suggests that the center of the low-attenuation layer is located within the uppermost mantle at about 70 km depth. The origin of this low-attenuation anomaly can be attributed to low-attenuation bodies in the form of remnant fossil lithospheric fragments in the deep crust or the uppermost mantle. The contribution of scattering to the observed Δt* is relatively weaker in the Gulf of Mexico Coastal Plain, which is suggestive of a more homogenous crustal and uppermost mantle structure. The first regional-scale 3-D P- wave attenuation model demonstrates high-attenuation anomalies at the northern and southern tips of the Malawi Rift Zone (MRZ) and an elongated NE-SW strip of low- attenuation anomaly traversing central MRZ. The high attenuation zone beneath the Rungwe Volcanic Province is confined to the upper mantle, which can be associated with decompression melting in response to continental extension. The prominent low- attenuation anomaly beneath the Luangwa Rift Zone that traverses the central part of the MRZ suggests the presence of a relatively thick cratonic lithosphere and possibly advocates the southward subsurface extension of the Bangweulu block --Abstract, page iv

Abdominal tuberculosis: a study of 50 cases

Background: The main type of tuberculosis of interest to any hospital- based surgeon is intestinal, the clinical presentation of which varies from one of an acute abdomen to one of a protracted cause of ill health and morbidity with a notorious reputation for poor response to therapy, both conservative as well as surgical. Low socio- economic status and malnutrition in our country are very important causes of the high prevalence of pulmonary tuberculosis, and with superadded problems of overcrowding and poor access to good sanitation and neglect for medical attention, extra pulmonary forms of tuberculosis also form a sizeable proportion of the case load of tuberculosis. The major source of infection is the open untreated case of pulmonary tuberculosis.Methods: Presented here is a brief account of hospital- based study of the presentation of 50 cases of abdominal tuberculosis and its management in both the acute as well as chronic setting, carried out at the B. Y. L. Nair Municipal Hospital Mumbai.Results: In our study 40% patients presented with signs of intestinal obstruction, 6% with perforative peritonitis, 34% with diffuse or well defined lump and 54% with ascites. All these patients underwent biochemical, radiological and endoscopic investigations.All the cases in this study were put on antitubercular four drug regime. Isoniazid (5mg / kg), Rifampicin (5-10mg/kg), Ethambutol (15mg/kg) and Pyrazinamide (20-25mg/kg) for two months followed by Isoniazid and Rifampicin for seven months. None of the patients developed drug toxicity during treatment. In our study out of 50 patients, 24 patients were treated conservatively. These includes 12 with tuberculous peritonitis (2 of the 12 had associated paraortic lymphadenopathy), 6 with subacute intestinal obstruction, 4 with RIF lump and 2 with colonic pathology) were treated conservatively. 26 patients underwent surgical treatment. Out of these 26 patients, 14 were operated in emergency and 12 were operated electively. Emergency surgeries were performed after correction of fluid electrolyte imbalance. Of the 14 emergency cases, 3 patients underwent resection anastomosis of small bowel, 6 patients underwent right hemicolectomy for iieocaecal tuberculosis. One patient had a stricturoplasty for ileal stricture in addition to right hemicolectomy. One patient underwent a stricturoplasty for ileal stricture and one unstable patient underwent drain insertion under local anaesthesia to drain out contaminated peritoneal fluid. Remaining two patients underwent adhesiolysis.Conclusions: In this study 60% patients had an acute and subacute presentation and 40% patients had a chronic presentation.

Management of hepatic hydatidosis by open versus laparoscopic surgery

Background:Aim of current study was to compare between laparoscopic versus open management of the hydatid cyst of liver regarding complication rate, post-operative recovery course with different modality of treatment and hospital stay. This study shows our results of surgical treatment of liver hydatid cysts during a 2.5 years period.Methods:A prospective study of 30 patients operated on in a 2.5 year period (April 2011 to October 2013) in department of general surgery of J.N. medical college, Sawangi (Meghe), Wardha, Maharashtra, with hepatic hydatid cyst. All patients were preoperatively treated with albendazole. 15 patients were tackled by laparoscopic technique (using Palanivelu hydatid system) and rest 15 underwent Open procedure as surgical approach.Results:Patients operated by laparoscopic surgery shown a better post-operative recovery course, required less analgesia, mobilized and started on oral feed early, intra-abdominal drain was removed at a much earlier period as compared to open group patient, this not only reduced morbidity but also because of this patient could be discharged earlier.Conclusion:Minimal invasive management, using Palanivelu hydatid system for aspiration and laparoscopic intervention, is an alternative to open surgery because of its ability to prevent spillage and thus minimize recurrences. It is better and safe to use laparoscopy in treatment of hydatid liver with less morbidity, mortality and recurrence rate in comparison with open technique.

Slit2N/Robo1 Inhibit HIV-gp120-Induced Migration and Podosome Formation in Immature Dendritic Cells by Sequestering LSP1 and WASp

Cell-mediated transmission and dissemination of sexually-acquired human immunodeficiency virus 1 (HIV-1) in the host involves the migration of immature dendritic cells (iDCs). iDCs migrate in response to the HIV-1 envelope protein, gp120, and inhibiting such migration may limit the mucosal transmission of HIV-1. In this study, we elucidated the mechanism of HIV-1-gp120-induced transendothelial migration of iDCs. We found that gp120 enhanced the binding of Wiskott-Aldrich Syndrome protein (WASp) and the Actin-Related Protein 2/3 (Arp2/3) complex with β-actin, an interaction essential for the proper formation of podosomes, specialized adhesion structures required for the migration of iDCs through different tissues. We further identified Leukocyte-Specific Protein 1 (LSP1) as a novel component of the WASp-Arp2/3-β-actin complex. Pretreating iDCs with an active fragment of the secretory glycoprotein Slit2 (Slit2N) inhibited HIV-1-gp120-mediated migration and podosome formation, by inducing the cognate receptor Roundabout 1 (Robo1) to bind to and sequester WASp and LSP1 from β-actin. Slit2N treatment also inhibited Src signaling and the activation of several downstream molecules, including Rac1, Pyk2, paxillin, and CDC42, a major regulator of podosome formation. Taken together, our results support a novel mechanism by which Slit2/Robo1 may inhibit the HIV-1-gp120-induced migration of iDCs, thereby restricting dissemination of HIV-1 from mucosal surfaces in the host

A Countdown to Orthognathic Surgery

For patients whose orthodontic problems are so severe that neither growth modification nor camouflage offers a solution, surgery to realign the jaws or reposition dentoalveolar segments is the only possible treatment. Surgery is not a substitute for orthodontics in these patients. Instead, it must be properly coordinated with orthodontics and other dental treatment to achieve good overall results

Hormonal and non-hormonal oral contraceptives given long-term to pubertal rats differently affect bone mass, quality and metabolism

IntroductionWe investigated the effects of hormonal and non-hormonal oral contraceptives (OCs) on bone mass, mineralization, composition, mechanical properties, and metabolites in pubertal female SD rats.MethodsOCs were given for 3-, and 7 months at human equivalent doses. The combined hormonal contraceptive (CHC) was ethinyl estradiol and progestin, whereas the non-hormonal contraceptive (NHC) was ormeloxifene. MicroCT was used to assess bone microarchitecture and BMD. Bone formation and mineralization were assessed by static and dynamic histomorphometry. The 3-point bending test, nanoindentation, FTIR, and cyclic reference point indentation (cRPI) measured the changes in bone strength and material composition. Bone and serum metabolomes were studied to identify potential biomarkers of drug efficacy and safety and gain insight into the underlying mechanisms of action of the OCs.ResultsNHC increased bone mass in the femur metaphysis after 3 months, but the gain was lost after 7 months. After 7 months, both OCs decreased bone mass and deteriorated trabecular microarchitecture in the femur metaphysis and lumbar spine. Also, both OCs decreased the mineral: matrix ratio and increased the unmineralized matrix after 7 months. After 3 months, the OCs increased carbonate: phosphate and carbonate: amide I ratios, indicating a disordered hydroxyapatite crystal structure susceptible to resorption, but these changes mostly reversed after 7 months, indicating that the early changes contributed to demineralization at the later time. In the femur 3-point bending test, CHC reduced energy storage, resilience, and ultimate stress, indicating increased susceptibility to micro-damage and fracture, while NHC only decreased energy storage. In the cyclic loading test, both OCs decreased creep indentation distance, but CHC increased the average unloading slope, implying decreased microdamage risk and improved deformation resistance by the OCs. Thus, reduced bone mineralization by the OCs appears to affect bone mechanical properties under static loading, but not its cyclic loading ability. When compared to an age-matched control, after 7 months, CHC affected 24 metabolic pathways in bone and 9 in serum, whereas NHC altered 17 in bone and none in serum. 6 metabolites were common between the serum and bone of CHC rats, suggesting their potential as biomarkers of bone health in women taking CHC.ConclusionBoth OCs have adverse effects on various skeletal parameters, with CHC having a greater negative impact on bone strength

Spectroscopic studies on transition metal iron complexes of 2-(N-Aryl ethanimidoyl) phenol as ligands

740-747The spectroscopic studies of transition metal complexes of iron. metal complexes, are characterized by XRD, FTIR, 1H NMR, Mössbauer and VSM (vibrating sample magnetometer) measurements, are reported in the present paper. The XRD analysis reveals the crystalline nature of all the compounds. Mössbauer study interprets paramagnetic nature of complexes at room temperature. VSM measurements also reveal the paramagnetic nature of complexes at higher temperature range, while complexes follow magnetic phase transition from paramagnetic to anti-ferromagnetic nature at low temperature

Teleseismic P

Seismic attenuation is an important parameter for characterizing subsurface morphology and thermal structure. In this study, we use P-wave amplitude spectra from 588 teleseismic events recorded by 477 broadband seismic stations in the southeastern United States to examine the spatial variations of seismic attenuation in the crust and upper mantle. The resulting seismic attenuation parameter (∆t*) measurements obtained using the spectral ratio technique reveal a zone of relatively low attenuation in the Gulf of Mexico Coastal Plain and the southwestern terminus of the Piedmont province. Spatial coherency analysis of the ∆t* observations suggests that the center of the low attenuation layer is located within the uppermost mantle at about 70 km depth. This low attenuation anomaly lies along the suture zone between Laurentia and Gondwana and approximately coincides with the east-west trending Brunswick magnetic anomaly. The origin of this low attenuation anomaly can be attributed to low attenuation bodies in the form of remnant lithospheric fragments in the deep crust and the uppermost mantle. The contribution of scattering to the observed ∆t* is estimated by calculating the ratio of amplitude on the transverse and vertical components in the P-wave window. Relative to the rest of the study area, the Gulf of Mexico Coastal Plain demonstrates weaker scattering which is suggestive of a more homogenous crustal and uppermost mantle structure