Coupled Ocean-Atmosphere Summer Intraseasonal Oscillation over the Bay of Bengal

This study shows the active role of subsurface ocean temperature in the evolution of coupled intra-seasonal oscillation (ISO) in the Bay of Bengal (BoB) using multi-satellite observations and ocean analysis product. Satellite-derived humidity profiles obtained from the atmospheric infrared sounder (AIRS) show that intense rains over the BoB are associated with the moistening (drying) in the lower and mid-troposphere during the active (break) phase of summer intraseasonal oscillation (ISO). Anomalous moistening in the mid-troposphere up to 500 hPa ahead of the maximum precipitation band over north BoB gives a precursor signal for the northward movement of the rain band. During the active (break) phase, the upper-tropospheric positive (negative) temperature anomaly ahead of the maximum rain band also sets a precondition by heating the mid- to upper troposphere. Daily subsurface temperature from Global Ocean Data Assimilation System (GODAS) analysis show that during the active phase, tropospheric moistening (drying) coincides with the subsurface warm (cold) temperature up to 200-m depth. The upper ocean warms uniformly by \~ 1 degrees C during the active phase as compared to the break phase in the entire BoB. The presence of a thin warm layer below the maximum rain band creates an environment conducive to sustaining the active phase on the ISO time scale. A positive sea surface temperature (SST) anomaly along with upper ocean warming ahead of a rain band in the north BoB in association with lower and mid-tropospheric moistening sets a precondition for the northward movement of the rain band. The anomalous warming (cooling) in the thermocline is associated with deeper (shallower) thermocline depth 23 degrees isotherms (D23)] and coincides with the mixed-layer warmin

Near-surface salinity and stratification in the north Bay of Bengal from moored observations

A thin layer of fresh water from summer monsoon rain and river runoff in the Bay of Bengal (BoB) has profound influence on air-sea interaction across the south Asian region, but the mechanisms that sustain the low-salinity layer are as yet unknown. Using the first long time series of high-frequency observations from a mooring in the north BoB and satellite salinity data, we show that fresh water from major rivers is transported by large-scale flow and eddies, and shallow salinity stratification persists from summer through the following winter. The moored observations show frequent 0.2–1.2 psu salinity jumps with time scales of 10 min to days, due to O(1–10) km submesoscale salinity fronts moving past the mooring. In winter, satellite sea surface temperature shows 10 km wide filaments of cool water, in line with moored data. Rapid salinity and temperature changes at the mooring are highly coherent, suggesting slumping of salinity-dominated fronts. Based on these observations, we propose that submesoscale fronts may be one of the important drivers for the persistent fresh layer in the north Bo

Outcomes in Hepatitis C Positive Liver Transplantation: Timing of Direct-Acting Antiviral Treatment and Impact on Graft Fibrosis

Liver transplantation for hepatitis C virus (HCV)-related disease has the lowest five-year graft survival among all liver transplant recipients. Graft failure due to accelerated fibrosis from unrestrained HCV replication is common. Optimal timing of HCV treatment with direct-acting antiviral agents remains unknown. We compared HCV liver transplant recipients successfully treated for HCV before transplant to those treated within 1 year of transplant to determine if graft fibrosis, measured by Fib-4 scores, differs with timing of treatment. Fib-4 scores less than or equal to 1.45 defined minimal fibrosis and greater than 1.45 defined greater than minimal fibrosis. We identified 117 liver transplant recipients: 52 treated before transplantation and 65 treated within 1 year of transplantation. Overall, 34% of recipients had minimal fibrosis, and the likelihood of having minimal fibrosis following treatment and liver transplantation did not differ by timing of treatment. The odds ratio of having greater than minimal fibrosis was 0.65 (95% CI 0.30, 1.42) among those treated within 1 year after transplantation compared to those treated before transplantation (p-value 0.28). Importantly, nearly 2/3 of these patients had evidence of fibrosis progression one year after sustained virologic response, supporting recommendations for early antiviral-based treatment to prevent accumulation of HCV-related disease

Eight Weeks of Ledipasvir/Sofosbuvir in Kidney Transplant Recipients With Hepatitis C Genotype 1 Infection

Abstract. Short treatment duration of ledipasvir/sofosbuvir (LDV/SOF) has been successfully used to treat hepatitis C virus (HCV) genotype 1 infection in treatment-naive noncirrhotic patients with viral loads (VLs) under 6 million IU/mL. However, this short duration has not been studied in renal transplant recipients (RTRs), a patient population on lifelong immunosuppression. Here, we describe 3 RTRs who received 8 weeks of LDV/SOF, meeting the standard criteria for shortened treatment duration. All 3 patients tolerated treatment well and achieved sustained virologic response at 12 weeks (SVR 12)