Mild modification method for the generation of mesoporosity in synthetic and natural mordenite

Zeolites are widely used as acid catalysts for the synthesis of fine chemicals in industrial processes. However, in most cases, diffusion limitations in the microporous network of zeolites prevents a good catalytic performance. In this sense, in the course of our research we have modified synthetic and natural mordenite zeolites by mild dealumination/desilication process to obtain mesoporosity. Commercial mordenite (CBV21A Si/Al = 10.5), and natural mordenite from Ethiopia (Si/Al = 6.2) have been treated under mild conditions (pH = 6) in order to maintain high crystallinity in the final zeolites. The impact of this mild treatment (based on ammonium acetate) is remarkable in the synthetic mordenite, creating good degree of mesoporosity while maintaining the bulk Si/Al ratio and crystallinity of the sample. In the case of the natural mordenite, the treatment leads to strong increase in the crystallinity of the sample, although only small mesoporosity is created. All samples were characterized by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), N2 adsorption-desorption isotherms and transmission electron microscopy (TEM). KEY WORDS: Zeolites, Mordenite, Natural mordenite, Modification, Mesoporous zeolites Bull. Chem. Soc. Ethiop. 2015, 29(1), 95-103DOI: http://dx.doi.org/10.4314/bcse.v29i1.

Baseline for ostracod-based northwestern Pacific and Indo-Pacific shallow-marine paleoenvironmental reconstructions: ecological modeling of species distributions

Fossil ostracods have been widely used for Quaternary paleoenvironmental reconstructions, especially in marginal marine environments (e.g., for water depth, temperature, salinity, oxygen levels, pollution). But our knowledge of indicator species autoecology, the base of paleoenvironmental reconstructions, remains limited and commonly lacks robust statistical support and comprehensive comparison with environmental data. We analyzed marginal marine ostracod taxa at 52 sites in Hong Kong for which comprehensive environmental data are available. We applied linear regression models to reveal relationships between species distribution and environmental factors for 18 common taxa (mainly species, a few genera) in our Hong Kong dataset and identified indicator species of environmental parameters. For example, Sinocytheridea impressa, a widely distributed euryhaline species throughout the East and South China Sea and the Indo-Pacific, indicates eutrophication and bottom-water hypoxia. Neomonoceratina delicata, a widely known species from nearshore and estuarine environments in the East and South China Sea and the Indo-Pacific, indicates heavy metal pollution and increased turbidity. The 18 taxa used for this study are widely distributed geographically and divided into the following groups: widespread (throughout the northwestern Pacific and Indo-Pacific regions), temperate (South China Sea to Russia (Sea of Japan coast) and Japan), subtropical (Indo-Pacific to the East China Sea), tropical (Indo-Pacific and South China Sea), and globally distributed. With statistical support from ecological modeling and comprehensive environmental data, these results provide a robust baseline for ostracod-based Quaternary–Anthropocene paleoenvironmental reconstructions in the tropical–extratropical northwestern Pacific and Indo-Pacific. Highlights. We provide a robust baseline for ostracod-based (microscopic Arthropods) paleoenvironmental reconstructions from Quaternary and Anthropocene marginal marine sediments. The studied species have wide distributions over the tropics and extratropics of the northwestern Pacific and Indo-Pacific. Ecological modeling has established ostracod species as reliable indicators for paleoenvironmental reconstructions.</ol

The calcitic test growth rate of <i>Spirillina vivipara</i> (Foraminifera)

Foraminifera encompass vastly differing morphologies, ecological preferences, and elemental/isotopic test compositions. The calcification mechanism is completely unknown for some wall-type taxa and might be different from that of well-studied groups. This study aims to understand the test growth and determine the calcification rate of Spirillina vivipara Ehrenberg, 1843 (order Spirillinida) and to compare them to other foraminiferal species. Spirillinids have a closely coiled spiral chamber like a tube, yet their calcitic microstructure is unique amongst foraminifera. Calcification observations in S. vivipara facilitate the estimation of carbonate precipitation rates during active test growth, which are revealed to be independent of the individual's size. Spirillina vivipara grows its test in response to food availability, suggesting that calcification directly corresponds to cell growth. Time-lapse observations of S. vivipara indicate continuous growth, suggesting active growth phases interspersed with resting periods, hinting at potential biological rhythms in the growth and calcification process. We also implemented a 24 h observation period using calcein staining, showing calcite precipitation rates of 8.08 µm h−1, which corresponds to approximately 364 nmol cm−2 min−1 (i.e., 36.4 mg cm−2 min−1). These rates are higher than those of other foraminiferal species and those in most inorganic precipitation experiments. Such high rates in spirillinid foraminifera may explain their distinctive morphology, elemental composition, unusual reproduction, and ecological distribution.</p

Population Based Survey of Chronic Non-Communicable Diseases at Gilgel Gibe Field Research Center, Southwest Ethiopia

BACKGROUND: Chronic Non-communicable Diseases are increasingly becoming more prevalent and burden to the health care system in developing countries including Ethiopia. However, evidences showing the magnitude of the problem in those countries are scarce particularly in a community setting.The objective of this study was to determine the magnitude of chronic non communicable diseases in a community.METHODS: A population-based cross-sectional study was conducted in Gilgel Gibe Field Research Center from late September 2008 to end of January 2009. A random sample of 4,469 individuals aged 15-64 years was studied. Data on characteristics and chronic symptom inventories were collected by interviewing study participants. Blood pressure was taken three times from each individual and blood sugar and lipid levels were determined after an overnight fasting. Data were analyzed using SPSS for Windows version 16.0 and STATA 11.RESULTS: The overall prevalence of CNCD was 8.9% (7.8% men and 9.8% women). The specific observed prevalence were 0.5% for diabetes mellitus (DM), 2.6% for hypertension, 3.0% for cardiovascular diseases, 1.5% for asthma and 2.7% for mental illness. In addition 3.1% and 9.3% of the study population had been informed to have DM and hypertension respectively.CONCLUSION: There is a high prevalence of CNCD among the study population indicating an immediate need for preventive action and also warrant further nationally representative study.Keywords: CNCD, Non-communicable, Prevalence, Southwest Ethiopi

Probucol Suppresses Enterocytic Accumulation of Amyloid-β Induced by Saturated Fat and Cholesterol Feeding

Amyloid-β (Aβ) is secreted from lipogenic organs such as intestine and liver as an apolipoprotein of nascent triacylglycerol rich lipoproteins. Chronically elevated plasma Aβ may compromise cerebrovascular integrity and exacerbate amyloidosis—a hallmark feature of Alzheimer’s disease (AD). Probucol is a hypocholesterolemic agent that reduces amyloid burden in transgenic amyloid mice, but the mechanisms for this effect are presently unclear. In this study, the effect of Probucol on intestinal lipoprotein-Aβ homeostasis was explored. Wild-type mice were fed a control low-fat diet and enterocytic Aβ was stimulated by high-fat (HF) diet enriched in 10% (w/w) saturated fat and 1% (w/w) cholesterol for the duration of 1 month. Mice treated with Probucol had the drug incorporated into the chow at 1% (w/w). Quantitative immunofluorescence was utilised to determine intestinal apolipoprotein B (apo B) and Aβ abundance. We found apo B in both the perinuclear region of the enterocytes and the lacteals in all groups. However, HF feeding and Probucol treatment increased secretion of apo B into the lacteals without any change in net villi abundance. On the other hand, HF-induced enterocytic perinuclear Aβ was significantly attenuated by Probucol. No significant changes in Aβ were observed within the lacteals. The findings of this study support the notion that Probucol suppresses dietary fat induced stimulation of Aβ biosynthesis and attenuate availability of apo B lipoprotein-Aβ for secretion

Risk factors for brucellosis and knowledge-attitude practice among pastoralists in Afar and Somali regions of Ethiopia

BACKGROUND: Brucellosis is a neglected bacterial zoonotic disease with substantial economic impact on households. Pastoral communities are a potential risk group due to their way of life being closely interlinked with their large livestock herds. METHODOLOGY: A semi-structured questionnaire survey was conducted in households in the pastoral Afar and Somali (SRS) regions. All households had people and animals serologically tested for brucellosis. Questions were related to husbandry, consumption habits, and knowledge-attitude-practice towards the disease and zoonoses. Descriptive statistics and logistic analysis were performed to assess potential risk factors for having households with positive humans and/or animals. RESULT: 647 households were included in the survey. Herd brucellosis prevalence was 40.3 % (15.9-86.3 % in Afar; 4-72.2 % in SRS). Over half (56.3 %) of the households in Afar and 41.8 % in SRS had at least one human reactor. Nearly a quarter of the households (22.8 %), recalled abortions in goats in the last 12 months, whereas 52.5 % and 50.3 % recalled stillborn in all species and membrane retentions respectively. All respondents drank raw milk and discarded animal afterbirths in the direct surroundings with minimal protection. Risk factors for animal reactors were goat herd size, and goat abortion. There was no identified risk factor for having human reactors in households. None of the households knew about brucellosis. CONCLUSION: Although being endemic in Afar and SRS, Brucellosis is not known by the pastoralists. Brucellosis control programs will have to be tailored to the pastoral context, accounting for their mobility, large, multi-species herds and habits

Integrated human-animal sero-surveillance of Brucellosis in the pastoral Afar and Somali regions of Ethiopia

BACKGROUND: Brucellosis is widespread in Ethiopia with variable reported prevalence depending on the geographical area, husbandry practices and animal species. However, there is limited information on the disease prevalence amongst pastoral communities, whose life is intricately linked with their livestock. METHODOLOGY: We conducted an integrated human-animal brucellosis sero-surveillance study in two adjacent pastoral regions, Afar and Somali region (SRS). This cross-sectional study included 13 woredas (districts) and 650 households. Blood samples were collected from people and livestock species (cattle, camel, goats and sheep). Sera were analyzed with C-ELISA for camels and shoats (sheep and goats), with I-ELISA for cattle and IgG ELISA for humans. Descriptive and inferential statistics analyses were performed. RESULTS: A total of 5469 sera were tested by ELISA. Prevalence of livestock was 9.0% in Afar and 8.6% in SRS (ranging from 0.6 to 20.2% at woreda level). In humans, prevalence was 48.3% in Afar and 34.9% in SRS (ranging from 0.0 to 74.5% at woreda level). 68.4% of all households in Afar and 57.5% of households in SRS had at least one animal reactor. Overall, 4.1% of animals had a history of abortion. The proportion of animals with abortion history was higher in seropositive animals than in seronegative animals. Risk factor analysis showed that female animals were significantly at higher risk of being reactors (p = 0.013). Among the species, cattle had the least risk of being reactors (p = 0.014). In humans, there was a clear regional association of disease prevalence (p = 0.002). The older the people, the highest the odds of being seropositive. CONCLUSION: Brucellosis is widespread in humans and animals in pastoral communities of Afar and SRS with the existence of geographical hotspots. No clear association was seen between human and particular livestock species prevalence, hence there was no indication as whether B. abortus or B. melitensis are circulating in these areas, which warrants further molecular research prior to embarking on a national control programs. Such programs will need to be tailored to the pastoral context

Quarkonium dissociation by anisotropy

We compute the screening length for quarkonium mesons moving through an anisotropic, strongly coupled N=4 super Yang-Mills plasma by means of its gravity dual. We present the results for arbitrary velocities and orientations of the mesons, as well as for arbitrary values of the anisotropy. The anisotropic screening length can be larger or smaller than the isotropic one, and this depends on whether the comparison is made at equal temperatures or at equal entropy densities. For generic motion we find that: (i) mesons dissociate above a certain critical value of the anisotropy, even at zero temperature; (ii) there is a limiting velocity for mesons in the plasma, even at zero temperature; (iii) in the ultra-relativistic limit the screening length scales as $(1-v^2)^\epsilon$ with \epsilon =1/2, in contrast with the isotropic result \epsilon =1/4.Comment: 39 pages, 26 figures; v2: minor changes, added reference