The Contribution of Human Activities to Dissolved Inorganic Carbon Fluxes in a Karst Underground River System: Evidence From Major Elements and ?(13)CDIC in Nandong, Southwest China.
The contribution of human activities to dissolved inorganic carbon fluxes in a karst underground river system: Evidence from major elements and ?(13)CDIC in Nandong, Southwest China.
J Contam Hydrol. 2013 Jun 11; 152C: 1-11
Jiang Y
Generally, the DIC in karst groundwater is dominantly derived from carbonate dissolution by carbonic acid. However, recently increases in the inorganic carbon flux have been linked to human activities, which nitric and sulfuric acids may contribute to carbonate dissolution. In order to quantify the sources and fluxes of DIC, and evaluate the carbon isotopic evolution of groundwater in Southwest China, the carbonate dissolution by carbonic, sulfuric and nitric acids was evaluated by hydrochemistry and ?(13)CDIC of groundwater. The results show that: (1) groundwater collected from residential and agricultural areas, showed higher DIC concentrations and ?(13)CDIC than those in groundwater collected from forested and grass land areas; (2) the contributions of carbonate dissolution by carbonic acid to total DIC concentrations in groundwater collected from forested and grass land areas averaged 99%; (3) the contributions of carbonate dissolution by carbonic acid to total DIC concentrations in groundwater, collected from residential and agricultural areas, varied from 40% to 77% with a mean percentage of 62%; (4) while the contributions of carbonate dissolution by sulfuric and nitric acids to total DIC concentrations in groundwater, collected from residential and agricultural areas, varied from 23% to 60% with a mean percentage of 38%; and (5) the ?(13)CDIC approaching a value of around -14‰, with a molar ratio between (Ca(2+)+Mg(2+)) and HCO3(-) of around 0.5 in groundwater, indicated that the carbonate was dissolved by soil CO2 from C3 vegetation under open system conditions. While the ?(13)CDIC varying from -5‰ to -11‰, with a variational molar ratio between (Ca(2+)+Mg(2+)) and HCO3(-) of 0.5 to 0.8 in groundwater, indicated that carbonate dissolution was controlled by soil CO2 (from C3 vegetation), HNO3 and H2SO4. Also, this study indicated that the amount of soil or atmospheric CO2 consumed during carbonate weathering should be critically evaluated when sulfuric or nitric acids are involved. Thus, not only the exports of inorganic carbon have been enhanced, but also the concentrations of nitrate and sulfate in karst groundwater have been elevated due to carbonate dissolution by sulfuric or nitric acid. HubMed – rehab
Efficacy of newer versus older antihypertensive drugs in black patients living in sub-Saharan Africa.
J Hum Hypertens. 2013 Jun 27;
M’buyamba-Kabangu JR, Anisiuba BC, Ndiaye MB, Lemogoum D, Jacobs L, Ijoma CK, Thijs L, Boombhi HJ, Kaptue J, Kolo PM, Mipinda JB, Osakwe CE, Odili A, Ezeala-Adikaibe B, Kingue S, Omotoso BA, Ba SA, Ulasi II, Staessen JA
To address the epidemic of hypertension in blacks born and living in sub-Saharan Africa, we compared in a randomised clinical trial (NCT01030458) single-pill combinations of old and new antihypertensive drugs in patients (30-69 years) with uncomplicated hypertension (140-179/90-109?mm?Hg). After ?4 weeks off treatment, 183 of 294 screened patients were assigned to once daily bisoprolol/hydrochlorothiazide 5/6.25?mg (n=89; R) or amlodipine/valsartan 5/160?mg (n=94; E) and followed up for 6 months. To control blood pressure (<140/<90?mm?Hg), bisoprolol and amlodipine could be doubled (10?mg per day) and ?-methyldopa (0.5-2?g per day) added. Sitting blood pressure fell by 19.5/12.0?mm?Hg in R patients and by 24.8/13.2?mm?Hg in E patients and heart rate decreased by 9.7 beats per minute in R patients with no change in E patients (-0.2 beats per minute). The between-group differences (R minus E) were 5.2?mm?Hg (P<0.0001) systolic, 1.3?mm?Hg (P=0.12) diastolic, and 9.6 beats per minute (P<0.0001). In 57 R and 67 E patients with data available at all visits, these estimates were 5.5?mm?Hg (P<0.0001) systolic, 1.8?mm?Hg (P=0.07) diastolic and 9.8 beats per minute (P<0.0001). In R compared with E patients, 45 vs 37% (P=0.13) proceeded to the higher dose of randomised treatment and 33 vs 9% (P<0.0001) had ?-methyldopa added. There were no between-group differences in symptoms except for ankle oedema in E patients (P=0.012). In conclusion, new compared with old drugs lowered systolic blood pressure more and therefore controlled hypertension better in native African black patients.Journal of Human Hypertension advance online publication, 27 June 2013; doi:10.1038/jhh.2013.56. HubMed – rehab
Surgical management in patient with uveitis.
Indian J Ophthalmol. 2013 Jun; 61(6): 284-290
Murthy SI, Pappuru RR, Latha KM, Kamat S, Sangwan VS
Surgery in the management of uveitis can be divided based on indication: either for therapeutic or can be for diagnostic purposes or to manage complications. The commonest indications include: Visual rehabilitation: surgery for removal of cataract, band keratopathy, corneal scars, pupillary membranes, removal of dense vitreous membranes, management of complications: anti-glaucoma surgery, vitreous hemorrhage, retinal detachment and chronic hypotony and diagnostic: aqueous tap, vitreous biopsy, tissue biopsy (iris, choroid). In this review, we shall describe the surgical technique for visual rehabilitation and for management of complications. HubMed – rehab