23 research outputs found
Electrofermentation increases concentration of poly γ‐glutamic acid in Bacillus subtilis biofilms
Full text linkAbstract Fluctuations in redox conditions in bioprocesses can alter the end‐products, reduce their concentration, and lengthen the process time. Electrofermentation enables rapid metabolic modulation of biosynthesis and allows control of redox imbalances in biofilm‐based fermentation processes. In this study, electrofermentation is used to boost the production of the bacterial biopolymer poly‐γ‐glutamic acid (γ‐PGA) from Bacillus subtilis ATCC 6051. When compared to control experiments (3.3 ± 0.99 g L−1), the application of an electrode potential E = 0.4 V versus Ag/AgCl results in a more than two‐fold increase in the production of γ‐PGA (9.13 ± 1.4 g L−1). Using an engineered B. subtilis strain, in which γ‐PGA production is driven by isopropyl β‐d‐1‐thiogalactopyranoside, electrofermentation improves polymer concentrations from 15.4 ± 1.5 to 23.1 ± 1.6 versus g L−1. These results confirm that electrofermentation conditions can be adopted to increase the concentration of γ‐PGA and perhaps other extracellular biopolymers in industrial strains
Management of Helicobacter pylori among medical doctors working in Khartoum, Sudan 2019: a cross-sectional study
Full text linkBackground: Various international guidelines have been developed regarding Helicobacter pylori (H. pylori) management, as it is infecting more than half of the world's population. Sudan's health system lacks guidelines regarding H. pylori management, leading to a discrepancy in practice. Investigating the current approach could be a step forward in the formulation of a national consensus in the management of H. pylori.
Methods: A cross-sectional study was conducted among medical doctors currently working in Khartoum, Sudan. Participants were enrolled from platforms of medical associations through an online questionnaire. The questionnaire was scored out of 25 points, and scoring 13 or above considered a good approach. Data analysis was carried out using Statistical Package for Social Sciences (SPSS).
Results: A total of 358 medical doctors participated in the study. The mean (±SD) score was 12.9(±4.5). Those who were using textbooks, campaigns, symposiums or general medical information to their primary Source of knowledge significantly scored higher. The most selected indication for both diagnosis (76.8%) and treatment (67.6%) was an active peptic ulcer. Stool antigen test (SAT) was the most preferred test (70.7%). The majority of respondents selected triple therapy (82.1%) as a first-line regimen. Only 37.7% confirmed the eradication after four weeks of stopping the treatment. They ensure eradication mainly through SAT (29%).
Conclusion: A suboptimal approach was noted among medical doctors of Khartoum, Sudan, regarding H. pylori management. Efforts should be invested in forming national guidelines and the implementation of continuous medical education programs.
Keywords: Helicobacter pylori, Medical doctor, Sudan
Anti-Factor H Antibodies in Egyptian Children with Hemolytic Uremic Syndrome
No full textBackground. Atypical hemolytic uremic syndrome (aHUS) is an important cause of acute kidney injury in children. It is primarily caused by dysregulation of the complement alternative pathway due to genetic mutations, mainly in complement factor H genes, or due to anti-factor H autoantibodies (anti-FH), leading to uncontrolled overactivation of the complement system. Early diagnosis and treatment of autoimmune HUS (AI-HUS) is essential and leads to a favorable outcome. Methods. Fifty pediatric HUS patients and 50 age- and sex-matched controls were included in the study. Patients were subjected to full history taking, clinical examination, and laboratory testing. All candidates were subjected to an assessment of anti-FH in serum by a homemade enzyme-linked immunosorbent assay technique. Results. A high frequency of serum anti-FH was detected in our aHUS patients. The disease onset of AI-HUS was mainly observed in March and April, with significantly higher rates in school-aged males. All patients who started immunosuppressives early together with plasmapheresis upon detection of their anti-FH had complete renal function recovery. Conclusion. The high frequency of AI-HUS revealed in Egyptian HUS children in our study highlights the importance of implementing anti-FH testing in Egypt to provide early recognition for immediate proper management, including early immunosuppressive therapy, and hence improving patient outcomes
Micellization Behavior and Thermodynamic Characteristics of Saponin and SDS: The Impact of Silica Nanoparticles for Subsurface Formation Interaction Studies
No full textThis study investigates the temperature-dependent micellization behaviors of saponin and sodium dodecyl sulfate (SDS) surfactants, which are both important for chemical enhanced oil recovery (CEOR). It also evaluates the effect of silica nanoparticles (SiO2) on these behaviors, given the growing interest in nanoparticle-enhanced surfactants. The research focuses on the tunable properties of nanoparticle-surfactant combinations. The structural differences between saponin and SDS were identified using FT-IR and H-NMR. The Du Noüy ring method was used to measure surface tension at various concentrations and temperatures (25–75 °C). FTIR analysis showed distinct differences between SDS and Saponin, associated with head group where there is hydroxyl groups in SDS solution. H-NMR showed higher complexity of Saponin's structure, evidenced by its diverse sugar-related proton peaks. Both SDS and Saponin reduce surface tension with temperature; SDS is more effective, lowering it to 42.1 mN/m versus 48.5 mN/m for Saponin. With SiO2, tensions drop to 39.2 mN/m for SDS and 45.5 mN/m for Saponin. Both surfactants maintain CMCs under reservoir temperature in the 0.05–0.1 wt % range. Saponin exhibited a more negative ΔG° and consistently negative ΔH°, indicating a thermodynamically favorable exothermic reaction. The novelty of this study lies in its focus on both anionic and nonionic surfactants under simulated reservoir conditions. The study focuses on the role of nanoparticles in enhancing surfactant stability and efficiency by addressing thermodynamic parameters.</p
Ginkgo biloba attenuates mucosal damage in a rat model of ulcerative colitis
No full textCorresponding Author: Hanan H. Hagar
Department of Pharmacology, College of Medicine & KKUH, King Saud University, P.O. Box 2925, Riyadh 11461, Saudi Arabia
Tel.: +96614786768, fax: +96614679289
Email: [email protected] inflammatory states, regardless of specific initiating events, share common immunologically mediated pathways of tissue injury and repair. The efficacy of various drugs used to treat ulcerative colitis (UC) was investigated. The aim of the present study is to evaluate the effects of ginkgo biloba extract on the extent and severity of UC caused by intracolonic administration of acetic acid in rats. The inflammatory response was assessed by histology and measurement of myeloperoxidase activity (MPO), reduced glutathione (GSH), tumor necrosis factor (TNF- ) and interleukin-1 (IL-1 ) levels in colon mucosa. Oral pretreatment with Ginkgo biloba in doses of (30, 60, 120 mg kg−1 body weight) and sulfasalazine in a dose of (500 mg kg−1 body weight used as reference) for 2 days before induction of colitis and continued for 5 consecutive days,
significantly decreased colonic MPO activity, TNF- , and IL-1 levels and increased GSH concentration. Moreover, Ginkgo biloba attenuated the macroscopic colonic damage and the histopathological changes-induced by acetic acid. These results suggest that Ginkgo biloba may be effective in the treatment of UC through its scavenging effect on oxygen-derived free radical
Experimental insights into synergestic SiO<sub>2</sub> nanoparticle/welan gum: the role of surface interaction in improving oil recovery
No full textThis study explored the synergistic interaction of SiO2 NPs and Welan gum for offshore application. Interaction characteristics, rheological behavior, Fluid-rock interaction and oil displacement were evaluated. FTIR, SEM and H-NMR were employed to characterize the SiO2-Welan gum solution. The results showed that SiO2 interacts with Welan gum through chemical bonds and possible hydrogen bonds due to hydroxyl group formation, increasing polymer roughness and causing network disruption. The incorporation of SiO2 NPs into welan gum resulted in a viscosity enhancement of up to 50% at 1.5 wt% salinity, demonstrating significant stability improvement. SiO2 NPs contribute to the thermal resistance of the polymer at elevated temperatures. Their synergistic effect was to mitigate salinity-induced viscosity reduction, maintaining fluid consistency more effectively than in the absence of nanoparticles. With SiO2, the adsorption between polymer and limestone decreased over time, showing an average reduction of 19%. The adsorption was homogeneous and was best described by the Langmuir isotherm model. The oil recovery improved by 15% more efficiently than the welan gum alone. The study suggests that SiO2 interacts with Welan gum in the ionic solution creating a three-dimensional network that resists conformational collapse and controls the polymer diffusion in limestone porous media
Vasospasm following aneurysmal subarachnoid hemorrhage: prediction, detection, and intervention
No full textAbstract Background Vasospasm of the cerebral blood vessels is a common complication of aneurysmal subarachnoid hemorrhage (aSAH) which results in delayed cerebral ischemia (DCI) and worsening of the outcome. Methods This study was performed on 41 aSAH patients diagnosed by non-contrast brain CT, CT angiography, and digital subtraction angiography followed by interventional aneurysmal embolization. Patients were followed up for 20 days by clinical assessment, EEG monitoring, and transcranial duplex studies (TCD) for early detection of vasospasm and DCI. Results The most common ruptured aneurysmal sites were middle cerebral, anterior communicating, posterior communicating, terminal internal carotid, and anterior cerebral arteries respectively. The incidence of vasospasm was 36.8% of the included cases; 57% progressed to DCI while 43% passed a spontaneous regressive course. The most common arteries undergoing vasospasm were the MCA followed by the ACA, ICA, and lastly the basilar arteries. The mean time of vasospasm development as detected by EEG monitoring and/or TCD was 8.4 ± 2.8 days which was earlier than clinical signs by 12.5 ± 5.3 h in those progressed to DCI. Conclusion Continuous EEG monitoring and TCD are valuable methods for early detection of vasospasm and they allow for early therapeutic intervention before irreversible ischemic neurological deficits take place
Prednisolone-Loaded PLGA Microspheres. In Vitro Characterization and In Vivo Application in Adjuvant-Induced Arthritis in Mice
No full textTransient pressure analysis for vertical oil exploration wells: a case of Moga field
Full text linkReservoir engineers use the transient pressure analyses to get certain parameters and variable factors on the reservoir’s physical properties, such as permeability thickness, which need highly sophisticated equipments, methods and procedures. The problem facing the exploration and production teams, with the discoveries of new fields, is the insufficiency of accurate and appropriate data to work with due to different sources of errors. The well-test analyst does the work without reliable set of data from the field, thus, resulting in many errors, which may consequently cause damage and unnecessary financial losses, as well as opportunity losses to the project. This paper analyzes and interprets the noisy production rate and pressure data with problematic mechanical damage using a deconvolution method. Deconvolution showed improvement in simulation results in detecting the boundaries. Also, high-risk area analysis with different methods being applied to get the best set of results needed for subsequent operations
Toward reducing surfactant adsorption on clay minerals by lignin for enhanced oil recovery application
Full text linkThe significant loss of surfactants during reservoir flooding is a challenge in oil field operations. The presence of clay minerals affects the surfactant performance, resulting in surfactant losses. This is because the mineralogical composition of the reservoir results in unpredicted adsorption quantity. Therefore, this paper seeks to investigate Aerosol-OT's adsorption on different quartz/clay mineral compositions during the flow. Also, it investigates adsorption mitigation by preflushing with lignin. The dynamic experiments were conducted on sand packs composed of quartz-sand and up to a 7% clay mineral content. The results obtained from the surfactant losses were compared with/without lignin preflush at different pH values. The main observation was the direct relationship between increasing the composition of clay minerals and the surfactant pore volume required to overcome the adsorption. The highest adsorption calculated was 46 g/kg for 7% kaolinite. Moreover, lignin successfully reduced the adsorption of Aerosol-OT by 60%. Therefore, the results demonstrate that the effects of the clay mineral content on adsorption could be efficiently minimized using lignin at a high pH
