Microbial activity and biomass and N and P availability in a saline sandy loam amended with inorganic N and lupin residues

Plant residue can be a cost effective source of N and P fertilisers, which may enhance plant growth in saline soils. Salinity and limited availability of N may limit microbial activity and thus residue decomposition N and P availability. A laboratory experiment was conducted to investigate the effects of NH4-N or NO3-N on microbial activity and biomass and N and P availability in a saline sandy loam. Three levels of salinity (EC1:5 0.21, 0.51 and 0.85 dS m-1) were imposed in the sandy loam using solutions of Na+ and Ca2+. Soil was amended with or without 2% (w/w) lupin residues (C/N ratio 15.4) or 50 μg N g-1 soil as KNO3 or (NH4)2.SO4. With no residue or inorganic N added, the concentration of available N and P remained unchanged over 45 days. Soil respiration and microbial biomass C, N and P decreased with increasing salinity, but significantly increased with residue addition. Addition of inorganic N had no significant effect, but addition of NO3-N with residue significantly increased soil respiration and microbial biomass C, N and P. Salinity had no effect on N availability and decreased P availability. Nitrogen availability was lower with addition of NH4-N, N than with NO3-N. Available N and P increased with residue addition and increased further with addition of NO3-N than with NH4-N. The greater C availability in the lupin residue amended saline sandy loam stimulated microbial activity and biomass with greater N demand, thus promoted immobilization of NO3. Hence, N and P availability increased in the saline sandy loam. © 2011 Elsevier Masson SAS.Ahmed Elgharably, Petra Marschne

Wheat growth in a saline sandy loam soil as affected by N form and application rate

First published online in 2009Plant growth in saline soils may be increased by fertilisation, but little is known about the effect of different forms of N on wheat growth in soils with different salinity levels. The aim of this study was to investigate the response of wheat (Triticum aestivum L., cv Krichauff) to (NH4)2SO4 or KNO3 or NH4NO3 at 0 (N0), 50 (N50), 100 (N100) and 200 (N200) mg N kg-1 soil in a saline sandy loam. Salinity was induced using Na+ and Ca2+ salts to achieve three ECe levels, 2. 8, 6. 6 and 11. 8 dS m-1 denoted S1, S2 and S3, respectively, while maintaining a low SAR (>1). Dry weights of shoot and root were reduced by salinity in all N treatments. Addition of N significantly increased shoot and root dry weights with significant differences between N forms. Under non-saline conditions (S1), addition of NO3-N at rates higher than N50 had a negative effect, while N100 as NH4-N or NH4NO3-N increased shoot and root dry weights. At N100, shoot concentrations of N and K were higher and P, Ca, Fe, Mn, Cu and Zn were lower with NO3-N than with NH4-N nutrition. The concentration of all nutrients however fell in ranges did not appear to be directly associated with poor plant growth with NO3-N. At all N additions, calculations indicated that soil salinity was highest with N addition as NO3-N and decreased in the following order: NO3-N > NH4-N > NH4NO3-N. Addition of greater than N50 as NO3 - N, compared to NH4-N or NH4-NO3, increased soil salinity and reduced micronutrient uptake both of which likely limited plant growth. It can be concluded that in saline soils addition of 100 mg N kg-1 as NH4-N or NH4NO3-N is beneficial for wheat growth, whereas NO3-N can cause growth depression. © Springer Science + Business Media B.V. 2009.Ahmed Elgharably, Petra Marschner and Pichu Rengasam

Hepatitis C in Egypt – Past, Present and Future

Hepatitis C viral infection is endemic in Egypt with the highest prevalence rate in the world. It is widely accepted that the implementation of mass population anti-schistosomal treatment involving administration of tartar emetic injections (between the 1950s to the 1980s) led to widespread infection. What is less well known, however, is that these schemes were implemented by the Egyptian Ministry of Health on the advice of the World Health Organisation. There has been a spectrum of treatments to target the public health disaster represented by the hepatitis C problem in Egypt: from the use of pegylated-Interferon to the recent use of direct acting antiviral drugs. Some new treatments have shown greater than 90% efficacy. However, cost is a key barrier to access of these new medicines. This is coupled with a growing population, limited resources and a lack of infection control practices which mean Egypt still faces significant disease control issues today

Hepatitis C in Egypt – past, present, and future

Ahmed Elgharably,1,2 Asmaa I Gomaa,2 Mary ME Crossey,1,2 Peter J Norsworthy,1 Imam Waked,2 Simon D Taylor-Robinson1 1Division of Digestive Health, Department of Surgery and Cancer, St Mary’s Hospital, Imperial College London, London, UK; 2National Liver Institute, Menoufiya University, Shebeen El Kom, Egypt Abstract: Hepatitis C viral infection is endemic in Egypt with the highest prevalence rate in the world. It is widely accepted that the implementation of mass population antischistosomal treatment involving administration of tartar emetic injections (from 1950s to 1980s) led to widespread infection. What is less well known, however, is that these schemes were implemented by the Egyptian Ministry of Health on the advice of the World Health Organization. There has been a spectrum of treatments to target the public health disaster represented by the hepatitis C problem in Egypt: from the use of PEGylated interferon to the recent use of direct acting antiviral drugs. Some new treatments have shown >90% efficacy. However, cost is a key barrier to access these new medicines. This is coupled with a growing population, limited resources, and a lack of infection control practices which means Egypt still faces significant disease control issues today. Keywords: hepatitis C, Egypt, schistosomiasi

Incidence, Risk Factors, and Outcomes Associated With Permanent Pacemaker Implantation Following Tricuspid Valve Surgery

Background Data regarding permanent pacemaker (PPM) implantation following tricuspid valve surgery (TVS) are limited. We sought to evaluate its incidence, risk factors, and outcomes. Methods and Results Medicare beneficiaries who underwent TVS from 2013 to 2020 were identified. Patients who underwent TVS for endocarditis were excluded. The primary exposure of interest was new PPM after TVS. Outcomes included all‐cause mortality and readmission with endocarditis or heart failure on follow‐up. Among the 13 294 patients who underwent TVS, 2518 (18.9%) required PPM placement. Risk factors included female sex (relative risk [RR], 1.26 [95% CI, 1.17–1.36], P<0.0001), prior sternotomy (RR, 1.12 [95% CI, 1.02–1.23], P=0.02), preoperative second‐degree heart block (RR, 2.20 [95% CI, 1.81–2.69], P<0.0001), right bundle‐branch block (RR, 1.21 [95% CI, 1.03–1.41], P=0.019), bifascicular block (RR, 1.43 [95% CI, 1.06–1.93], P=0.02), and prior malignancy (RR, 1.23 [95% CI, 1.01–1.49], P=0.04). Tricuspid valve (TV) replacement was associated with a significantly higher risk of PPM implantation when compared with TV repair (RR, 3.20 [95% CI, 2.16–4.75], P<0.0001). After a median follow‐up of 3.1 years, mortality was not different in patients who received PPM compared with patients who did not (hazard ratio [HR], 1.02 [95% CI, 0.93–1.12], P=0.7). PPM placement was not associated with a higher risk of endocarditis but was associated with a higher risk of heart failure readmission (HR, 1.28 [95% CI, 1.14–1.43], P<0.001). Conclusions PPM implantation frequently occurs after TVS, notably in female patients and patients undergoing TV replacement. Although mortality is not increased, it is associated with higher rates of heart failure rehospitalization