33 research outputs found
Synthesis and characterization of sago / polyvinyl alcohol blend pervaporation membrance for ethyl acetate recovery
Pervaporation is a membrane separation technology with high selectivity, efficiency and energy saving benefits that make it the method of choice for separation of mixtures. The application for pervaporation includes removal of dilute organic compounds from aqueous solution and dehydration of organics such as dehydration of ethyl acetate-water mixture. The best successful application that has been used for pervaporation is dehydration of organic liquid from water using hydrophilic polymer membrane. In this work, material used for membrane separation was sago and polyvinyl alcohol. However, during the separation process, excessive affinity of water towards hydrophilic polymer membrane led to an increase in the swelling of the membrane. To control the degree of swelling the membranes were cross-linked to improve the intrinsic properties of hydrophilic polymer membranes. Sago starch was used as based polymer to prepare membranes with polyvinyl alcohol (PVA) with various morphologies such as homogenous, composite and blended ration of sago and PVA. Sago/PVA membranes were cross-linked using three different approaches: firstly, using glutaraldehyde, secondly using thermal treatment (80 °C) and thirdly by using both glutaraldehyde and thermal treatment. The effects of various cross-linking methods on the intrinsic properties of hydrophilic polymer membrane were investigated. Before applying the cross-linking to sago/PVA membranes for separation of ethyl acetate-water mixture, a physicochemical characterization was carried out using Fourier transform infrared spectroscopy, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), atomic force microscopy and swelling experiments. The investigation on the effect of cross-linking on the sago/PVA membranes showed an increase in surface hydrophobicity from contact angle measurements. DSC measurements showed an increase in melting temperature of the polymer membranes after cross-linking. In addition, TGA showed an increase in the stability of the polymer membranes after cross-linking. The effects of operating condition such as feed temperature and feed concentration on the permeation flux and separation factor were also investigated. For the pervaporation of ethyl acetate-water mixture, a decrease in flux and an increase in the separation factor were observed with chemical and combination of chemical and thermal cross-linking. Finally, central composite designs (CCD) of response surface methodology was applied to analyse pervaporation performance of thermal cross-linked membrane. Regression models were developed for permeation flux and separation factor as a function of feed temperature, feed concentration and permeate pressur
Evaluating water controls on vegetation growth in the semi-arid sahel using field and earth observation data
Water loss is a crucial factor for vegetation in the semi-arid Sahel region of Africa. Global satellite-driven estimates of plant CO2 uptake (gross primary productivity, GPP) have been found to not accurately account for Sahelian conditions, particularly the impact of canopy water stress. Here, we identify the main biophysical limitations that induce canopy water stress in Sahelian vegetation and evaluate the relationships between field data and Earth observation-derived spectral products for up-scaling GPP. We find that plant-available water and vapor pressure deficit together control the GPP of Sahelian vegetation through their impact on the greening and browning phases. Our results show that a multiple linear regression (MLR) GPP model that combines the enhanced vegetation index, land surface temperature, and the short-wave infrared reflectance (Band 7, 2105-2155 nm) of the moderate-resolution imaging spectroradiometer satellite sensor was able to explain between 88% and 96% of the variability of eddy covariance flux tower GPP at three Sahelian sites (overall = 89%). The MLR GPP model presented here is potentially scalable at a relatively high spatial and temporal resolution. Given the scarcity of field data on CO2 fluxes in the Sahel, this scalability is important due to the low number of flux towers in the region
Smart two-tank water quality and level detection system via IoT
The two-tank water system is common practice for the storage and distribution of water in many homes. Water is transported via a pipeline network from the storage tank (lower tank) to the distribution tank (overhead tank) using an electric pumping machine. Due to limited control in the existing pumping system, water wastage becomes inevitable. Determining the quality of water in the overhead tank before supply in the home is still unaddressed. In this work, an integrated Android mobile App and a control system were developed to assess the water quality, perform level check in the overhead tank, and activate intelligent pumping control. An ultrasonic pulse-echo technique was used for water level checks, while the water turbidity and pH signals were used for water quality checks. Three-level control conditions (LC_1, LC_2, LC_3) and two water quality check conditions (QC_1 and QC_2) were devised and used in the intelligent control algorithm of the system. Control valve1 regulates the flushable poor water quality while valve2 regulates the house's supply of good water quality. The absolute relative error between the expected time and the system time of filling the tank level was observed to be less than 10% when the water volume is less than 81%. Hence, distortion in the sensory signals increases and worsen as the water level approaches the ultrasonic sensor position. The poor internet signal network was observed to affect the real-time monitoring and automation of the system control through delay in system responses to commands. However, the average recorded response time of the system is 3 s, and it could be less in the situation of good internet network services
Effect of sitagliptin on cardiovascular outcomes in type 2 diabetes
BACKGROUND: Data are lacking on the long-term effect on cardiovascular events of adding sitagliptin, a dipeptidyl peptidase 4 inhibitor, to usual care in patients with type 2 diabetes and cardiovascular disease. METHODS: In this randomized, double-blind study, we assigned 14,671 patients to add either sitagliptin or placebo to their existing therapy. Open-label use of antihyperglycemic therapy was encouraged as required, aimed at reaching individually appropriate glycemic targets in all patients. To determine whether sitagliptin was noninferior to placebo, we used a relative risk of 1.3 as the marginal upper boundary. The primary cardiovascular outcome was a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for unstable angina. RESULTS: During a median follow-up of 3.0 years, there was a small difference in glycated hemoglobin levels (least-squares mean difference for sitagliptin vs. placebo, -0.29 percentage points; 95% confidence interval [CI], -0.32 to -0.27). Overall, the primary outcome occurred in 839 patients in the sitagliptin group (11.4%; 4.06 per 100 person-years) and 851 patients in the placebo group (11.6%; 4.17 per 100 person-years). Sitagliptin was noninferior to placebo for the primary composite cardiovascular outcome (hazard ratio, 0.98; 95% CI, 0.88 to 1.09; P<0.001). Rates of hospitalization for heart failure did not differ between the two groups (hazard ratio, 1.00; 95% CI, 0.83 to 1.20; P = 0.98). There were no significant between-group differences in rates of acute pancreatitis (P = 0.07) or pancreatic cancer (P = 0.32). CONCLUSIONS: Among patients with type 2 diabetes and established cardiovascular disease, adding sitagliptin to usual care did not appear to increase the risk of major adverse cardiovascular events, hospitalization for heart failure, or other adverse events
Data for dynamics analysis of riverine dissolved organic in watersheds
This data article presents water stage, flow, and net primary productivity (NPP) data that were used to analyze the dynamics of the riverine dissolved organic carbon (DOC) dynamics in the Rukarara River watershed in Rwanda. We measured water stage data every 15 min and calculated daily averages used to estimate flow based on rating curves. The rating curves were produced using several measured contemporaneous water stage and flow data. Estimated flow data were used to calculate water dissolved organic carbon (DOC) loadings separate the total stream flow into quick and baseflow. Annual NPP data for a 15-year period were used to estimate the effect of proportion of stream DOC loading on carbon sequestration within the Rukarara River watershed
Examining the NDVI-rainfall relationship in the semi-arid Sahel using geographically weighted regression
The Sahel of Africa is an eco-sensitive zone with complex relations emerging between vegetation productivity and rainfall. These relationships are spatially non-stationary, non-linear, scale dependant and often fail to be successfully modelled by conventional regression models. In response, we apply a local modelling technique, Geographically Weighted Regression (GWR), which allows for relationships to vary in space. We applied the GWR using climatic data (Normalized Vegetation Difference Index and rainfall) on an annual basis during the growing seasons (June–September) for 2002–2012. The operating scale of the Sahelian NDVI–rainfall relationship was found to stabilize around 160 km. With the selection of an appropriate scale, the spatial pattern of the NDVI-rainfall relationship was significantly better explained by the GWR than the traditional Ordinary Least Squares (OLS) regression. GWR performed better in terms of predictive power, accuracy and reduced residual autocorrelation. Moreover, GWR formed spatial clusters with local regression coefficients significantly higher or lower than those that the global OLS model resulted in, highlighting local variations. Areas near wetlands and irrigated lands displayed weak correlations while humid areas such as the Sudanian region at southern Sahel produced higher and more significant correlations. Finally, the spatial relationship of rainfall and NDVI displayed temporal variations as there were significant differences in the spatial trends throughout the study period
Riverine dissolved organic carbon in Rukarara River Watershed, Rwanda
Dissolved organic carbon (DOC) loading is rarely estimated in tropical watersheds. This study quantifies DOC loading in the Rukarara River Watershed (RRW), a Rwandan tropical forest and agricultural watershed, and evaluates its relationship with hydrological factors, land use and land cover (LULC), and topography to better understand the impact of stream DOC export on watershed carbon budgets. The annual average load for the study period was 977.80 kg C, which represents approximately 8.44% of the net primary productivity of the watershed. The mean daily exports were 0.37, 0.14, 0.075 and 0.32 kg C/m2 in streams located in natural forest, tea plantation, small farming areas, and at the outlet of the river, respectively. LULC is a factor that influences DOC loading. The quick flow was the main source of stream DOC at all study sites. Stream DOC increases with increasing water flow, indicating a positive relationship. Thus, the expectation is that a change in land cover and/or rainfall will result in a change of stream DOC dynamics within the watershed. Topography was also found to influence the dynamics of stream DOC through its effect on overland flow in terms of drainage area and total length of flow paths. Tea plantations were located in areas of high drainage density and projected increase of rainfall in the region, as a consequence of climate change, could increase stream DOC content and affect stream water quality, biodiversity, balance between autotrophy and heterotrophy, and bioavailability of toxic compounds within the RRW
Long Non-Coding RNAs ANRIL and HOTAIR Upregulation is Associated with Survival in Neonates with Sepsis in a Neonatal Intensive Care Unit
Nouran B AbdAllah,1 Essam Al Ageeli,2 Abdullah Shbeer,3 Jawaher A Abdulhakim,4 Eman A Toraih,5,6 Doaa O Salman,6 Manal S Fawzy,7,8 Sanaa S Nassar1 1Department of Pediatrics, Faculty of Medicine, Suez Canal University, Ismailia, Egypt; 2Department of Clinical Biochemistry (Medical Genetics), Faculty of Medicine, Jazan University, Jazan, Saudi Arabia; 3Anesthesiology and Intensive Care, Department of Surgery, Faculty of Medicine, Jazan University, Jazan, Saudi Arabia; 4Medical Laboratory Department, College of Applied Medical Sciences, Taibah University, Yanbu, Saudi Arabia; 5Division of Endocrine and Oncologic Surgery, Department of Surgery, School of Medicine, Tulane University, New Orleans, LA, USA; 6Genetics Unit, Department of Histology and Cell Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt; 7Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt; 8Department of Biochemistry, Faculty of Medicine, Northern Border University, Arar, Saudi ArabiaCorrespondence: Manal S Fawzy, Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt, Email [email protected] Eman A Toraih, Division of Endocrine and Oncologic Surgery, Department of Surgery, School of Medicine, Tulane University, New Orleans, LA, USA, Email [email protected]: Recently, long non-coding RNAs (lncRNAs) have emerged as potential molecular biomarkers for sepsis. We aimed to profile the expression signature of three inflammation-related lncRNAs, MALAT1, ANRIL, and HHOTAIR, in the plasma of neonates with sepsis and correlate these signatures with the phenotype.Patients and Methods: This case–control study included 124 neonates with sepsis (88 survivors/36 non-survivors) admitted to the neonatal ICU and 17 healthy neonates. The relative expressions were quantified by real-time PCR and correlated to the clinic-laboratory data.Results: The three circulating lncRNAs were upregulated in the cases; the median levels were MALAT1 (median = 1.71, IQR: − 0.5 to 3.27), ANRIL (median = 1.09, IQR: 0.89 to 1.30), and HOTAIR (median = 1.83, IQR: 1.44 to 2.41). Co-expression analysis showed that the three studied lncRNAs were directly correlated (all p-values < 0.001). Overall and stratification by sex analyses revealed significantly higher levels of the three lncRNAs in non-survivors compared to the survivor group (all p-values < 0.001). Principal component analysis showed a clear demarcation between the two study cohorts in males and females. Cohorts with upregulated ANRIL (hazard ratio; HR = 4.21, 95% CI = 1.15– 10.4, p=0.030) and HOTAIR (HR = 2.49, 95% CI = 1.02– 6.05, p=0.044) were at a higher risk of mortality.Conclusion: Circulatory MALAT1, ANRIL, and HOTAIR were upregulated in neonatal sepsis, and the latter two may have the potential as prognostic biomarkers for survival in neonatal sepsis.Keywords: neonatal sepsis, long non-coding RNAs, MALAT1, ANRIL, HOTAIR, surviva