1,402 research outputs found
A comparative study to determine the clinical efficacy of Ramipril versus combination of Ramipril and Telmisartan in reducing microalbuminuria associated with grade 2 hypertension
Inhibition of the renin-angiotensin system causes a reduction in urinary protein excretion. It is uncertain whether Angiotensin receptor blockers (ARBs) are equally effective antiproteinuric agents as Angiotensin converting Enzyme (ACE) inhibitors, or whether the combination of ACE inhibitors with ARBs is preferable to ACE inhibitor alone? Microalbuminuria is a prognostic marker for cardiovascular and renal risk. The objective of the study was to compare the clinical efficacy of Ramipril alone versus combination of Ramipril and Telmisartan by assessing the fall in B.P. and the improvement in the degree of microalbuminuria in stage II hypertensive patients. 60 patients of stage II hypertension without having any other cause of microalbuminuria were selected as subjects for the present study and were randomly distributed in to 2 groups- Group A included 30 patients who were given Ramipril 5 mg/ day and Group B included the same number of patients who were given a combination of Ramipril 5 mg/day and Telmisartan 40 mg/day. Baseline parameters included were measurement of Systolic, diastolic blood pressure and mean arterial pressure; microalbuminuria, blood urea, serum creatinine and serum potassium estimations. The drugs under trial were given for 20 weeks. Microalbuminuria was determined at 0 and 20 weeks. The mean percentage fall in microalbuminuria and mean arterial pressure were statistically highly significant (p<0.0001) with combination of Ramipril and Telmisartan (Group B) in comparison to Ramipril (Group A) alone. A highly significant (p‹ 0.0001) mean percentage increase in potassium level was observed in group B at the end of 20 weeks. The side effects were less observed in the combination group. Thus to conclude the combination of Ramipril and Telmisartan provides superior blood pressure (BP) lowering and target organ protection than Ramipril alone, hence the combination of Ramipril and Telmisartan is a better choice to treat and to prevent the progression of the disease.Keywords: Hypertension; Microalbuminuria; Ramipril; Telmisarta
AmniSure: A Point of Care Diagnostic for Preterm, Term Prelabor Rupture of Membranes
Background: Accurate, early diagnosis, prompt appropriate intervention is essential in the management of rupture of membranes (ROM), especially preterm. Aim: The aim was to determine efficacy of AmniSure rapid immunoassay placental alpha‑microglobulin‑1 test for accurate diagnosis of true ROM in women with watery discharge after 28 weeks gestation, compare with conventional methods. Subjects and Methods: Study was carried out in women presenting with ROM to labor the room of referral rural medical institute in Central India after ethical approval. Prospective study was performed in women presenting with symptoms/signs of ROM after 28 weeks of gestation. Sterile speculum examination was performed to observe pooling of liquor. Nitrazine, ferning tests were done to diagnose ROM. Vaginal examination was performed to determine cervical dilatation, effacement, station of presenting part in term cases. If all or 2 of 3 tests (pooling, ferning, and nitrazine) were positive, provisional diagnosis of ROM was made. Confirmation of ROM was done at birth. However, if 2 of 3 tests were negative, sterile speculum examination was repeated after 30 min of the first test. Test performance was calculated by comparing AmniSure results against final diagnosis at birth. Of 200 patients between 28 and 42 weeks gestation recruited for study, 31.5% (63/200) were preterm, 68.5% (137/200) term. Statistical analysis of data collected in the electronic database using SPSS version (Amnisure International LLC, 30 JFK Street, 4th Floor, Cambridge, MA 02138, USA). Results: AmniSure rapid immunoassay, rapid method for diagnosis of ROM, has 100% specificity, 99.44% sensitivity (one false negative due to meconium and immediate cesarean section). Conclusion: In comparison to nitrazine, pooling, ferning, AmniSure has almost 100% sensitivity, specificity.Keywords: AmniSure, diagnosis, meconium, preterm, term rupture of membrane
Controlling the Morphology of Aggregates of an Amphiphilic Synthetic Receptor through Host-Guest Interactions
A new amphiphilic receptor containing a macrocyclic anionic headgroup and a single alkyl chain was prepared through an efficient templated synthesis. The interdependence of the aggregation behavior and the host-guest chemistry was studied. In the absence of any guest the terminus of the alkyl chain of the receptor is included inside the hydrophobic cavity of the macrocycle (as evident from 1H NMR studies) leading to self-assembly into micrometer-long nanotubes (as evident from TEM studies). The alkyl chain can be displaced by an acridizinium bromide guest (as evident from 1H NMR and ITC), which leads to a dramatic change in aggregate size and morphology (as evident from DLS). Studies of the solubilization of Nile red suggest that the resulting aggregates are micelles with a cmc of around 35 µM. These results represent a new addition to the still small number of water-soluble amphiphilic receptors and one of the first examples in which specific host-guest chemistry controls the size and shape of nanoscale aggregates.
Modeling of secondary organic aerosol yields from laboratory chamber data
Laboratory chamber data serve as the basis for constraining models of secondary organic aerosol (SOA) formation. Current models fall into three categories: empirical two-product (Odum), product-specific, and volatility basis set. The product-specific and volatility basis set models are applied here to represent laboratory data on the ozonolysis of α-pinene under dry, dark, and low-NOx conditions in the presence of ammonium sulfate seed aerosol. Using five major identified products, the model is fit to the chamber data. From the optimal fitting, SOA oxygen-to-carbon (O/C) and hydrogen-to-carbon (H/C) ratios are modeled. The discrepancy between measured H/C ratios and those based on the oxidation products used in the model fitting suggests the potential importance of particle-phase reactions. Data fitting is also carried out using the volatility basis set, wherein oxidation products are parsed into volatility bins. The product-specific model is most likely hindered by lack of explicit inclusion of particle-phase accretion compounds. While prospects for identification of the majority of SOA products for major volatile organic compounds (VOCs) classes remain promising, for the near future empirical product or volatility basis set models remain the approaches of choice
Changes in organic aerosol composition with aging inferred from aerosol mass spectra
Organic aerosols (OA) can be separated with factor analysis of aerosol mass spectrometer (AMS) data into hydrocarbon-like OA (HOA) and oxygenated OA (OOA). We develop a new method to parameterize H:C of OOA in terms of f_(43)(ratio of m/z 43, mostly C_2H_3O^+, to total signal in the component mass spectrum). Such parameterization allows for the transformation of large database of ambient OOA components from the f_(44) (mostly CO^+_2, likely from acid groups) vs. f_(43) space ("triangle plot") (Ng et al., 2010) into the Van Krevelen diagram (H:C vs. O:C) (Van Krevelen, 1950). Heald et al. (2010) examined the evolution of total OA in the Van Krevelen diagram. In this work total OA is deconvolved into components that correspond to primary (HOA and others) and secondary (OOA) organic aerosols. By deconvolving total OA into different components, we remove physical mixing effects between secondary and primary aerosols which allows for examination of the evolution of OOA components alone in the Van Krevelen space. This provides a unique means of following ambient secondary OA evolution that is analogous to and can be compared with trends observed in chamber studies of secondary organic aerosol formation. The triangle plot in Ng et al. (2010) indicates that f_(44) of OOA components increases with photochemical age, suggesting the importance of acid formation in OOA evolution. Once they are transformed with the new parameterization, the triangle plot of the OOA components from all sites occupy an area in Van Krevelen space which follows a ΔH:C/ΔO:C slope of ~ −0.5. This slope suggests that ambient OOA aging results in net changes in chemical composition that are equivalent to the addition of both acid and alcohol/peroxide functional groups without fragmentation (i.e. C-C bond breakage), and/or the addition of acid groups with fragmentation. These results provide a framework for linking the bulk aerosol chemical composition evolution to molecular-level studies
Secondary organic aerosol formation from m-xylene, toluene, and benzene
Secondary organic aerosol (SOA) formation from the photooxidation of m-xylene, toluene, and benzene is investigated in the Caltech environmental chambers. Experiments are performed under two limiting NOx conditions; under high-NOx conditions the peroxy radicals (RO2) react only with NO, while under low-NOx conditions they react only with HO2. For all three aromatics studied (m-xylene, toluene, and benzene), the SOA yields (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) under low-NOx conditions substantially exceed those under high-NOx conditions, suggesting the importance of peroxy radical chemistry in SOA formation. Under low-NOx conditions, the SOA yields for m-xylene, toluene, and benzene are constant (36%, 30%, and 37%, respectively), indicating that the SOA formed is effectively nonvolatile under the range of Mo(>10 μg m−3) studied. Under high-NOx conditions, aerosol growth occurs essentially immediately, even when NO concentration is high. The SOA yield curves exhibit behavior similar to that observed by Odum et al. (1996, 1997a, b), although the values are somewhat higher than in the earlier study. The yields measured under high-NOx conditions are higher than previous measurements, suggesting a "rate effect" in SOA formation, in which SOA yields are higher when the oxidation rate is faster. Experiments carried out in the presence of acidic seed aerosol reveal no change of SOA yields from the aromatics as compared with those using neutral seed aerosol
Gaussian phase autocorrelation as an accurate compensator for FFT-based atmospheric phase screen simulations
Accurately simulating the atmospheric turbulence behaviour is always challenging. The well-known FFT based method falls short in correctly predicting both the low and high frequency behaviours. Sub-harmonic compensation aids in low-frequency correction but does not solve the problem for all screen size to outer scale parameter ratios (G/L₀). FFT-based simulation gives accurate result only for relatively large screen size to outer scale parameter ratio (G/L₀). In this work, we have introduced a Gaussian phase autocorrelation matrix to compensate for any sort of residual errors after applying for a modified subharmonics compensation. With this, we have solved problems such as under sampling at the high-frequency range, unequal sampling/weights for subharmonics addition at low-frequency range and the patch normalization factor. Our approach reduces the maximum error in phase structure-function in the simulation with respect to theoretical prediction to within 1.8%, G/L₀ = 1/1000
Analysis of photochemical and dark glyoxal uptake: Implications for SOA formation
The dependence of glyoxal uptake onto deliquesced ammonium sulfate seed aerosol was studied under photochemical (light + hydroxyl radical (OH)) and dark conditions. In this study, the chemical composition of aerosol formed from glyoxal is identical in the presence or absence of OH. In addition, there was no observed OH dependence on either glyoxal uptake or glyoxal-driven aerosol growth for this study. These findings demonstrate that, for the system used here, glyoxal uptake is not affected by the presence of OH. In combination with previous studies, this shows that the exact nature of the type of seed aerosol, in particular the presence of a coating, has a large influence on fast photochemical uptake of glyoxal. Due to the challenge of relating this seed aerosol dependence to ambient conditions, this work highlights the resulting difficulty in quantitatively including SOA formation from glyoxal in models
Glyoxal uptake on ammonium sulphate seed aerosol: reaction products and reversibility of uptake under dark and irradiated conditions
Chamber studies of glyoxal uptake onto ammonium sulphate aerosol were performed under dark and irradiated conditions to gain further insight into processes controlling glyoxal uptake onto ambient aerosol. Organic fragments from glyoxal dimers and trimers were observed within the aerosol under dark and irradiated conditions. Glyoxal monomers and oligomers were the dominant organic compounds formed under the conditions of this study; glyoxal oligomer formation and overall organic growth were found to be reversible under dark conditions. Analysis of high-resolution time-of-flight aerosol mass spectra provides evidence for irreversible formation of carbon-nitrogen (C-N) compounds in the aerosol. We have identified 1H-imidazole-2-carboxaldehyde as one C-N product. To the authors' knowledge, this is the first time C-N compounds resulting from condensed phase reactions with ammonium sulphate seed have been detected in aerosol. Organosulphates were not detected under dark conditions. However, active photochemistry was found to occur within aerosol during irradiated experiments. Carboxylic acids and organic esters were identified within the aerosol. An organosulphate, which had been previously assigned as glyoxal sulphate in ambient samples and chamber studies of isoprene oxidation, was observed only in the irradiated experiments. Comparison with a laboratory synthesized standard and chemical considerations strongly suggest that this organosulphate is glycolic acid sulphate, an isomer of the previously proposed glyoxal sulphate. Our study shows that reversibility of glyoxal uptake should be taken into account in SOA models and also demonstrates the need for further investigation of C-N compound formation and photochemical processes, in particular organosulphate formation
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