Antimicrobial activity of 7,3ʹ,4ʹ-trihydroxyflavonol isolated from Acacia nilotica var. ad stringens

Acacia species (Mimosaceae) is widely distributed in tropical and subtropical countries and has a variety of ethnomedicinal uses. There is inadequate laboratory investigation to identify bioactive compounds and therapeutic effect of Acacia nilotica var. ad stringens. This research has been conducted to extract, isolate and identify major compounds from heartwood of Acacia nilotica var. ad stringens and to test them against representative bacteria. Powdered air-dried heartwood of A. nilotica var. ad stringens has been extracted with methanol/water, 4:1 and the extract has been then purified using chromatographic techniques (column and paper chromatography). A pure flavonoid compound has been isolated and the structure has been elucidated based on extensive spectroscopic analysis procedures (IR, UV, 1H NMR, and mass spectrometery). The isolated compound has then been evaluated for antimicrobial potential against Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus) using cup-plate agar diffusion method. The spectroscopic analysis of the isolated compound has led to its identification as 7,3ʹ,4ʹ-trihydroxyflavonol. The compound shows varying antimicrobial responses with high potency against Gram-negative human pathogens. The Gram-positive bacteria which are inhibited are Bacillus cereus, Corynebacterium sp., Enterococcus faecalis, Staphylococcus aureus , and Streptococcus agalactiae. The Gram-negative bacteria are Acinetobacterbaumannii , Acinetobacter sp. , Escherichia coli, Pseudomonas aeruginosa and yeasts are Candida albicans and Cryptococcus neoformans. The present study has demonstrated that 7,3ʹ,4ʹ-trihydroxyflavonol is an effective antimicrobial compound. If applied in suitable pharmaceutical formulations it could be valuable for treating various bacterial infections or introduced as adjunct treatment along with standard agents.

New approach towards the classification of microporosity in Miocene carbonate rocks, Central Luconia, offshore Sarawak, Malaysia

Microporosity is recognized as a significant concern in limestone reservoirs throughout the world because it presence can highly complicate the hydrocarbon estimation and production. Numerous studies around the globe emphasises on the physical appearance, occurrence, and abundance of microporosity, but no published study has been emphasises on the presence of microporosity in Miocene carbonate reservoirs. Miocene carbonates from Central Luconia, offshore Sarawak, Malaysia, contains a significant amount of micropores, which occurs in grain, matrix, and cement. For a better understanding of the presence of micropores, it is necessary to consider grains, matrix, cement, and pore types. Based on the qualitative and quantitative knowledge of these components a classification of micropores is proposed and their effect on reservoir quality. These results can reduce the number of the assumption made about the internal rock connectivity and quality.For quantitative analysis, 32 high-resolution images of each thin sections were taken under the transmitted light microscopy. Succeeding these 32 images were stacked together as a photo panel to enable quantifying the amount of grain, matrix, cement, pore types and macroporosity using Digital Image Analysis and J.Microvision software. Furthermore, Field Emission Scanning Electron Microscopy images were also used for the measurement of crystallometry of micrite particles, classification of micrite particles and the micropores.Eight facies scheme is introduced based on the detailed lithofacies study of five wells. The qualitative observation of thin sections unveiled that corals, red algae, green algae, foraminifera, echinoderms, sponge, bivalve, and bryozoans are the most dominant components. Foraminifera, red algae, and corals are the far most dominant components covering almost 50% of the total intervals. Regarding porosity types, the mouldic porosity is the far most dominant pore types with converting the total 50% of the interval. Lithofacies observed in these wells indicate a good reservoir quality, but diagenesis plays a vital role in enhancing or reducing their porosity and permeability. Most of the depositional textures of the reservoir are leached, making this location unique to study facies distribution and diagenetic history.Result exhibits that the micrite particles are classified into five classes, which are very fine, fine, medium, coarse and very coarse, with a diameter of 0.1–2 μm, 2–4 μm, 4–6 μm, 6–8 μm and 8–10 μm respectively. The texture and morphology of micrite microtexture are classified into six classes. Among these six classes, rounded, subrounded, trigonal, rhombic (micro-sub)-polyhedral micrite are representing porous micrite particles, whereas fitted bounded subhedral, and fitted fused anhedral are interpreted as tight micrite particles. Furthermore, five micropores classes are introduced based on the size of these particles. The empirical porosity-permeability relationship is affected by the presence of microporosity and its influences the assessment of ultimate recovery of hydrocarbons in Central Luconia, offshore Sarawak, Malaysia. Keywords: Quantification, Grain types, Porosity, Microporosity, Micrite particles, Central Luconi

Quantitative Interpretation of carbonate reservoir rock using wireline logs: a case study from Central Luconia, offshore Sarawak, Malaysia

The current study focuses on the quantitative evaluation of petrophysical parameters of selected wells using wireline log data in Central Luconia, offshore Sarawak. Based on the relatively high resistivity and, low-neutron/-density log responses, three major zones are identified. These include gas-bearing zones (Zone-1 and Zone-3) and mixed zone (Zone-2). The gamma ray, neutron and density logs confirmed that Well A was composed of carbonate rocks ranging from limestone to dolomite. Zone-1 and Zone-3 consist of limestone, whereas Zone-2 contains dolomite. The average porosity of these zones (Zone-1, Zone-2 and Zone-3) are 15.7, 4.3 and 13.7%, whereas gas saturation is 83, 41 and 93%, respectively. The permeability values are 543 mD (Zone-1), 47.7 mD (Zone-2) and 601.5 mD (Zone-3). The water saturation value in Zone-2 is very high, up to 66% compared to Zone-1 and Zone-3 which are 17 and 7%, respectively. It is pertinent to mention that Zone-1 and Zone-3 contain movable gas (i.e., HC movability index is less than 0.7). Furthermore, bulk volume water values in three zones (0.012, 0.0083 and 0.009) indicate the presence of irreducible water. In contrast, pore-filled dolomite cement is mostly from Zone-2, indicating high water, low gas saturation, low porosity and less movability index values, which indicate the presence of high microporosity. Additionally, bulk volume water suggests that these micropores are saturated with irreducible water. High microporosity affects the wireline log response in Zone-2 and therefore provides misleading information

The strategic plan for combating antimicrobial resistance in Gulf Cooperation Council States

Summary: The Gulf Cooperation Council Center for Infection Control (GCC-IC) has placed the emergence of antimicrobial resistance (AMR) on the top of its agenda for the past four years. The board members have developed the initial draft for the GCC strategic plan for combating AMR in 2014. The strategic plan stems from the WHO mandate to combat AMR at all levels. The need for engaging a large number of stakeholders has prompted the GCC-IC to engage a wider core of professionals in finalizing the plan. A multi-disciplinary group of more than 40 experts were then identified. And a workshop was conducted in Riyadh January 2015 and included, for the first time, representation of relevant ministries and agencies as well as international experts in the field. Participants worked over a period of two and a half days in different groups. International experts shared the global experiences and challenges in addressing human, food, animal, and environmental aspects of controlling AMR. Participants were then divided into 4 groups each to address the human, animal, microbiological and diagnostic, or the environmental aspect of AMR. At the end of the workshop, the strategic plan was revised and endorsed by all participants. The GCC-IC board members then approved it as the strategic plan for AMR. The document produced here is the first GCC strategic plan addressing AMR, which shall be adopted by GCC countries to develop country-based plans and related key performance indicators (KPIs). It is now the role of each country to identify the body that will be accountable for implementing the plan at the country level. Keywords: Strategic plan, Antimicrobial resistance, AMR, GCC, Saudi Arabia, United Arab Emirates, Qatar, Bahrain, Oman, Kuwai