Thermodynamic study of adsorption alcohols on natural clay by inverse gas chromatography

The adsorption of VOCs onto porous clays has been considered as an innovative research of environmental treatment. This work was performed to investigate the adsorption properties of alcohols vapors (ethanol and methanol) on natural clay using inverse gas chromatography (IGC). This method was based on the principle of the chromatography of elution in gas phase. From the IGC data, the adsorption isotherms of alcohols on natural clay were determined. These isotherms were used to calculate the thermodynamic parameters such as enthalpy and entropy and to find the appropriate adsorption model. Finally, the adsorptive performance in terms of adsorption of alcohols by natural clay has been compared to activated carbon. Keywords: Adsorption, Elution chromatography, isotherms, enthalpy, entropy

Effect of some tillage methods and sowing dates on bulk density, soil moisture and sorghum yield in the rainfed areas of northern Gedarif , Gedarif State , Sudan

     The study was carried out during three consecutive seasons (2005/06, 2006/07 and 2007/08) under rain-fed conditions, to investigate the effect of some tillage methods and sowing dates  of  sorghum (Sorghum bicolor L.) on soil moisture  content, bulk density and sorghum grain  yield  in  northern Gedarif area, at the pilot farm of the Faculty of Agricultural  and Environmental Sciences, University of  Gedarif, Gedarif, Sudan. The experiment was laid out in a split plot design with three replicates. Main plots were assigned to three tillage methods; which were:  Zero tillage (ZT), offset disc as post harvest tillage(PHT) and farmers practice which was  wide level disc (WLD) as control, while sub-plots were assigned  to two sowing dates  which were early sowing date (S1) and late sowing date (S2). Post-harvest tillage treatment (PHT) resulted in significantly higher soil moisture content in the three growing seasons  compared to the other two treatments. Combined analysis indicated that ZT resulted in  significantly higher soil bulk density  in comparison with WLD and PHT treatments  for the three depths. The 3-years average grain yield for PHT, WLD and ZT were 1113 kg/ha, 976 kg/ha and 885 kg/ha, respectively.  The respective increase in yield was  26% and 14%.                                                                                                                                                                              The study was carried out during three consecutive seasons (2005/06, 2006/07 and 2007/08) under rain-fed conditions, to investigate the effect of some tillage methods and sowing dates  of  sorghum (Sorghum bicolor L.) on soil moisture  content, bulk density and sorghum grain  yield  in  northern Gedarif area, at the pilot farm of the Faculty of Agricultural  and Environmental Sciences, University of  Gedarif, Gedarif, Sudan. The experiment was laid out in a split plot design with three replicates. Main plots were assigned to three tillage methods; which were:  Zero tillage (ZT), offset disc as post harvest tillage(PHT) and farmers practice which was  wide level disc (WLD) as control, while sub-plots were assigned  to two sowing dates  which were early sowing date (S1) and late sowing date (S2). Post-harvest tillage treatment (PHT) resulted in significantly higher soil moisture content in the three growing seasons  compared to the other two treatments. Combined analysis indicated that ZT resulted in  significantly higher soil bulk density  in comparison with WLD and PHT treatments  for the three depths. The 3-years average grain yield for PHT, WLD and ZT were 1113 kg/ha, 976 kg/ha and 885 kg/ha, respectively.  The respective increase in yield was  26% and 14%.                                                                                                                                                                       &nbsp

Cryoprotective Effect of l-Carnitine on Motility, Vitality and DNA Oxidation of Human Spermatozoa

Successful cryopreservation for human spermatozoa markedly influences the reproductive outcomes of assisted reproductive technologies. But in spite of its usefulness, cryopreservation significantly decreases sperm quality. l-carnitine has been found to improve the quality of spermatozoa in selected cases with male infertility. Here, we examined the efficacy of l-carnitine in improving sperm motility and vitality and reducing sperm DNA oxidation during cryopreservation. Semen samples from infertile patients (n = 22) were collected and analysed. Cryopreservation medium supplemented with l-carnitine was mixed with the semen at a ratio of 1 : 1 (v/v). The final l-carnitine concentration in each cryovial was 0.5 mg ml−1 per 5 × 106 cell ml−1. Controls were cryopreserved without addition of l-carnitine. After 24 h of cryopreservation, thawed sperm samples were analysed for motility, vitality and DNA oxidation. Sperm vitality was assessed by the eosin–nigrosin test, while sperm DNA oxidation was measured by flow cytometry. Addition of l-carnitine significantly improved sperm motility and vitality (P \u3c 0.05) compared with the control. The flow cytometry experiment showed no statistical difference (P \u3e 0.05) in the levels of DNA oxidation between samples and controls. In conclusion, l-carnitine improves human sperm motility and vitality, but has no effect on sperm DNA oxidation after cryopreservation

Reductive Decomposition of A Diazonium Intermediate by Dithiothreitol Affects The Determination of NOS Turnover Rates

Accurate determination of nitrite either as such or as the breakdown product of nitric oxide (NO) is critical in a host of enzymatic reactions in various settings addressing structure–function relationships, as well as mechanisms and kinetics of molecular operation of enzymes. The most common way to quantify nitrite, for instance in nitric oxide synthase (NOS) mechanistic investigations, is the spectrophotometric assay based on the Griess reaction through external standard calibration. This assay is based on a two-step diazotization reaction, in which a cationic diazonium derivative of sulfanilamide is formed as intermediate before the final absorbing azo-product. We show that this intermediate is very sensitive to reducing agents that may be transferred from the reaction media under investigation. The interaction of this vital intermediate with the reducing agent, dithiothreitol (DTT), which is widely used in NOS reactions, is characterized by both electrochemical and spectroscopic means. The effect of DTT on the performance of external calibration, both in sample recovery studies and in actual NOS reactions, is presented. Finally an alternative method of standard additions, which partially compensates for the accuracy and sensitivity problems of external calibration, is proposed and discussed

Human Sperm DNA Oxidation, Motility and Viability in The Presence of l-Carnitine During in Vitro Incubation and Centrifugation

In vitro incubation and centrifugation is known to decrease human sperm quality. In the human body, besides its antioxidant effects, l-carnitine (LC) facilitates the transport of activated fatty acids from the cytosol to the mitochondrial matrix. In this study, we investigated the effect of LC on human sperm motility, viability and DNA oxidation after incubation and centrifugation, following the sperm preparation protocols of assisted reproduction. Normozoospermic semen samples (n = 55) were analysed according to the World Health Organization (WHO) guidelines. LC concentrations that are not toxic to spermatozoa as determined by sperm motility and viability were standardised after 2 and 4 h of incubation at 37 °C. Semen samples to which the optimal LC concentrations were added were also centrifuged for 20 min at 300 g and analysed for sperm motility, viability and DNA oxidation. Sperm motility was improved at 0.5 mg ml−1 LC after incubation and centrifugation with 5 × 106 sperm ml−1. Higher concentration of LC (50 mg ml−1) significantly decreased sperm motility and viability. LC did not alter the baseline of sperm DNA oxidation during both incubation and centrifugation. In conclusion, LC may enhance sperm motility following incubation and centrifugation, while it might not affect sperm viability and DNA oxidation

A Clinicopathological Study of Urinary Bladder Neoplasms in Patients at Three Centers in Khartoum, Sudan

OBJECTIVES: To present the histopathological pattern of urinary bladder neoplasms using the WHO/ISUP classification system and relate it to the outcome.METHODS: This study was conducted in the period from January 2004 through December 2005 at three centres in Khartoum, Sudan. One hundred and six patients with urinary bladder neoplasms were included in the study.RESULTS: The commonest affected age group was 60-80 years with male to female ratio 4.6:1. Urothelial neoplasms were found in 72 (67.9%), Squamous cell carcinoma (SCC) in 26 (24.5%), urothelial neoplasms with Squamous differentiation in 3 (2.8%), and other types in 5 (4.7%) of thepatients. There were 43.4% of the urothelial neoplasms graded as papillary carcinoma of high grade, 52.6% papillary carcinoma of low grade, 1.3% papillary neoplasm of low malignant potential, 1.3% papilloma, and 1.3% was graded as flat neoplasm. Of the SCCs, twelve (42.9%)were poorly differentiated SCCs, nine (32.1%) moderately differentiated, and seven (25%) cases were well differentiated SCCs. Follow-up information was available in 32 patients. At last followup, fifteen (46.9%) patients were dead of the disease, twelve (35.5%) were alive with no evidence of disease, four (12.5%) were alive with disease, and one (3.1%) was alive and terminally ill. CONCLUSION: Histological grade (P: 0.006), and muscle invasion (P: 0.002) were significantly associated with survival. A subset of the cases could not be assessed for muscle invasion due toinadequate sampling; we thus recommend proper trans-urethral bladder biopsy (TUBP) sampling.Key words: Urinary bladder neoplasm; Papillary carcinoma; Squamous cell carcinoma; WHO/ISUP classification system

Human Sperm DNA Oxidation, Motility and Viability in The Presence of l-Carnitine During in Vitro Incubation and Centrifugation

In vitro incubation and centrifugation is known to decrease human sperm quality. In the human body, besides its antioxidant effects, l-carnitine (LC) facilitates the transport of activated fatty acids from the cytosol to the mitochondrial matrix. In this study, we investigated the effect of LC on human sperm motility, viability and DNA oxidation after incubation and centrifugation, following the sperm preparation protocols of assisted reproduction. Normozoospermic semen samples (n = 55) were analysed according to the World Health Organization (WHO) guidelines. LC concentrations that are not toxic to spermatozoa as determined by sperm motility and viability were standardised after 2 and 4 h of incubation at 37 °C. Semen samples to which the optimal LC concentrations were added were also centrifuged for 20 min at 300 g and analysed for sperm motility, viability and DNA oxidation. Sperm motility was improved at 0.5 mg ml−1 LC after incubation and centrifugation with 5 × 106 sperm ml−1. Higher concentration of LC (50 mg ml−1) significantly decreased sperm motility and viability. LC did not alter the baseline of sperm DNA oxidation during both incubation and centrifugation. In conclusion, LC may enhance sperm motility following incubation and centrifugation, while it might not affect sperm viability and DNA oxidation

Statistical modeling of the effect of rainfall flushing on dengue transmission in Singapore

Background: Rainfall patterns are one of the main drivers of dengue transmission as mosquitoes require standing water to reproduce. However, excess rainfall can be disruptive to the Aedes reproductive cycle by “flushing out” aquatic stages from breeding sites. We developed models to predict the occurrence of such “flushing” events from rainfall data and to evaluate the effect of flushing on dengue outbreak risk in Singapore between 2000 and 2016. Methods: We used machine learning and regression models to predict days with “flushing” in the dataset based on entomological and corresponding rainfall observations collected in Singapore. We used a distributed lag nonlinear logistic regression model to estimate the association between the number of flushing events per week and the risk of a dengue outbreak. Results: Days with flushing were identified through the developed logistic regression model based on entomological data (test set accuracy = 92%). Predictions were based upon the aggregate number of thresholds indicating unusually rainy conditions over multiple weeks. We observed a statistically significant reduction in dengue outbreak risk one to six weeks after flushing events occurred. For weeks with five or more flushing events, compared with weeks with no flushing events, the risk of a dengue outbreak in the subsequent weeks was reduced by 16% to 70%. Conclusions: We have developed a high accuracy predictive model associating temporal rainfall patterns with flushing conditions. Using predicted flushing events, we have demonstrated a statistically significant reduction in dengue outbreak risk following flushing, with the time lag well aligned with time of mosquito development from larvae and infection transmission. Vector control programs should consider the effects of hydrological conditions in endemic areas on dengue transmission.Charles Stark Draper Laborator

TTA solvation kinetics in the ionic liquid BumimTf2NTf_2N

TTA, a classical complexing agent of metallic cations, has been studied by UV–vis in the ionic liquid (IL) 1-methyl-3-butyl-imidazolium bistriflimide (BumimTf2N), in the presence of variable amounts of water. Depending on the water content, the keto-hydrate/enol equilibrium kinetics can last up to tens of hours. Modelling by use of classical homogeneous kinetic equations appears unsatisfactory, which pledges for the existence of non-homogeneous phenomena in such solutions, most probably related to the state of water in ILs

Fungicidal Activities and Mechanisms of Action of Pseudomonas syringae pv. syringae Lipodepsipeptide Syringopeptins 22A and 25A

The plant-associated bacterium Pseudomonas syringae pv. syringae simultaneously produces two classes of metabolites: the small cyclic lipodepsinonapeptides such as the syringomycins and the larger cyclic lipodepsipeptide syringopeptins SP22 or SP25. The syringomycins inhibit a broad spectrum of fungi (but particularly yeasts) by lipid-dependent membrane interaction. The syringopeptins are phytotoxic and inhibitory to Gram-positive bacteria. In this study, the fungicidal activities of two major syringopeptins, SP22A and SP25A, and their mechanisms of action were investigated and compared to those of syringomycin E. SP22A and SP25A were observed to inhibit the fungal yeasts Saccharomyces cerevisiae and Candida albicans although less effectively than syringomycin E. S. cerevisiae mutants defective in ergosterol and sphingolipid biosyntheses were less susceptible to SP22A and SP25A but the relative inhibitory capabilities of SRE vs. SP22A and SP25A were maintained. Similar differences were observed for capabilities to cause cellular K+ and Ca2+ fluxes in S. cerevisiae. Interestingly, in phospholipid bilayers the syringopeptins are found to induce larger macroscopic ionic conductances than syringomycin E but form single channels with similar properties. These findings suggest that the syringopeptins target the yeast plasma membrane, and, like syringomycin E, employ a lipid-dependent channel-forming mechanism of action. The differing degrees of growth inhibition by these lipodepsipeptides may be explained by differences in their hydrophobicities. The more hydrophobic SP22A and SP25A might interact more strongly with the yeast cell wall that would create a selective barrier for their incorporation into the plasma membrane