108 research outputs found

    A Novel Triterpene Saponin from Gypsophila capillaris

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    A novel C-28 tetraglycoside of quillaic acid (1) has been isolated from Gypsophila capillaris. The structure was elucidated by 1 D NMR (NOE difference, DEPT, selective13C{1H} INEPT), 2D NMR (1H,1H and1H,13C COSY,1H,1H,1H RELAY, ROESY and TOCSY) and other spectroscopic and chromatographic evidences. Conformational dynamics within the tetrasaccharide part were estimated from NOE responses and ROESY peaks. © 1995 Verlag der Zeitschrift fĂŒr Naturforschung. All rights reserved

    Towards the chemical control of molecular packing: syntheses and crystal structures of three trans-[NiL4(NCS)2] complexes

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    Three nickel(II) isothiocyanato complexes of the formula trans-[NiL4(NCS)2] (L = ethylisonicotinate, methylisonicotinate and 4-benzoylpyridine) have been prepared: [Ni(ethylisonicotinate) 4(NCS)2] (I), [Ni(methylisonicotinate)4(NCS)2] (II) and [Ni(4-benzoylpyridine)4(NCS)2] (III). All three complexes are monomeric and have a distorted octahedral geometry around NiII. Despite their apparent molecular similarity, the crystal density of (III) (1.454 g cm 3) is significantly higher than that of (I) and (II) (both 1.408 g cm 3), suggesting that the molecular packing is most efficient in (III). A study of the molecular Hirshfeld surfaces, together with density functional theory (DFT) calculations, provide insights into the origin of the molecular packing features, and it is suggested that the greater crystal density of (III) results from smaller intermolecular electrostatic repulsions

    DESIGN AND ASSESSMENT OF A SPEED-BASED INTEGRATED ACTIVE VEHICLE CONTROLLER FOR LATERAL STABILITY

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    An integrated active vehicle control system implementing fuzzy-logic control (FLC) is introduced. The system integrates three commercially- available active vehicle control systems, namely, Active Front Steering (AFS), Electronic Stability Control (ESC) and Torque Vectoring System (TVS) aiming at enhancing vehicle handling and cornering stability and rollover prevention. Two different vehicle models were constructed to simulate the dynamic behavior of the system with and without the proposed integration controller, namely, a 14-DOF vehicle dynamic model with nonlinear tire characteristics and a 2DOF bicycle reference model. Last model was utilized to generate controller’s reference values of vehicle’s yaw rate and body side slip angle at a given forward speed and driver’s steering input. Simulation was carried out in the MATLAB/SIMULINK software environment. The effectiveness of the system was investigated applying five different standard cornering test maneuvers at different vehicle forward speeds of 10, 20 and 30m/s. Simulated test maneuvers are: step, J-turn, single lane change (SLC), sine with dwell, (SWD) and fishhook.Results reveal that, for stability enhancement, AFS is most effective at low vehicle speeds with declining efficacy as speed goes up. Both ESC and TVS have been found to be equally effective at moderate to high speeds. In conclusion, an integrated chassis control (ICC) strategy has been proposed that improves vehicle handling and cornering performance across the entire operating range of speed using a forward-speed-based stability criterion to allocate stability control authority and ensure smooth transition of control between the three AFS, ESC, and TVS systems

    Assessment of <i>Helicobacter pylori </i>cytotoxin-associated Gene A (Cag A) protein and its association with ferritin and vitamin B12 deficiencies among adult healthy asymptomatic residents in Sharjah, United Arab Emirates

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    Introduction: The United Arab Emirates (UAE) serves as an effective epidemiological site for assessing Helicobacter pylori (H. pylori) infection due to its diverse population. However, comprehensive studies on the prevalence of H. pylori in the UAE are notably scarce. In depth prevalence studies are needed as a preventive measure against gastric cancer and other emerging extra gastric diseases associated with H. pylori infection. Aim: This study aimed to assess H. pylori infection and its virulent oncoprotein, the Cytotoxin-Associated Gene (Cag A) and its association with ferritin and vitamin B12 deficiencies. Methods: The study was conducted on 1094 healthy asymptomatic volunteers residents in the Sharjah Emirate, UAE. Enzyme-linked immunosorbent assay (ELISA) was performed to assess H. pylori infection using H. pylori antibodies (IgG), and detection of CagA protein using Cag A antibody (IgG) in the human serum. Ferritin and vitamin B12 serum levels were assessed and correlated to H. pylori infection. Results: This study focuses mainly on the assessment of H. pylori and its virulent factor CagA, in relation to vitamin B12 and ferritin deficiencies. Remarkably, 49.6 % of the participants were detected positive for H. pylori, with over half of these cases involving CagA positive strains. Notably, among Emirati participants, 76.11 % of those with H. pylori infection were CagA positive. Statistical analysis revealed a significant correlation between H. pylori, CagA level, and ferritin/vitamin B12 deficiencies. Conclusion: These findings emphasize the importance of timely detection and eradication of H. pylori not only as a preventive strategy against gastric cancer but also as an effective strategy to rescue the adverse effects from ferritin and vitamin B12 deficiencies, thereby improving the overall health outcomes of individuals affected by H. pylori infection.</p

    Synthesis, structure diversity, and antimicrobial studies of Ag(i) complexes with quinoline-type ligands

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    Compounds [Ag(5NO2Qu)2]BF4 (1) and [Ag(Qu3CN)(H2O)]BF4 (2) were prepared and studied from a structural perspective and screened for antimicrobial activity. The Ag(i) in the monomeric complex 1 is coordinated to two 5-nitroquinoline (5NO2Qu) ligands via the N-atoms of the quinoline rings with equidistant Ag-N bonds (2.146(2) \uc5) and a N-Ag-N# bond angle of 171.42(8)\ub0. The 2D coordination polymer 2 contains tetracoordinated Ag(i) with two N-atoms (N1 and N2#1) from two quinoline-3-carbonitrile (Qu3CN) ligands and two O-atoms (O1 and O1#1) from two water molecules. The Qu3CN ligand acts as a connector between the Ag(i) sites along the b-direction via two short Ag1-N1 (2.185(4) \uc5) and Ag1-N2#1 (2.204(4) \uc5) bonds. In addition, the Ag(i) is coordinated with two symmetry related water molecules which are also acting as connectors between the Ag(i) sites along the a-direction via two longer Ag1-O1 (2.470(4) \uc5) and Ag1-O1#2 (2.546(4) \uc5) bonds. Hirshfeld surface analysis confirmed the significance of the polar F⋯H contacts in the molecular packing of 1 (25.9%) and 2 (39.9%). In addition, the crystal packing of 1 showed a significant amount of polar O⋯H (23.5%) contacts. Also, both complexes displayed π-π stacking interactions. The Ag(i) complexes and the free ligand were assessed for their antimicrobial activities. It was found that 1 (MIC = 7.8 ÎŒg mL−1) and 2 (MIC = 31.25 ÎŒg mL−1) have higher antifungal potency against C. albicans than their free ligands (MIC = 125 ÎŒg mL−1). Interestingly, 1 has better antifungal activity than the standard nystatin (15.6 ÎŒg mL−1). Also, both Ag(i) complexes and the free ligands as well have better activity against P. mirabilis than the common antibiotic amoxicillin

    Mechanisms of Foreign Body Response Mitigation by Nitric Oxide Release

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    Implantable glucose biosensors provide real-time information about blood glucose fluctuations, but their utility and accuracy are time-limited due to the foreign body response (FBR) following their insertion beneath the skin. The slow release of nitric oxide (NO), a gasotransmitter with inflammation regulatory properties, from a sensor surface has been shown to dramatically improve sensors’ analytical biocompatibility by reducing the overall FBR response. Indeed, work in a porcine model suggests that as long as the implants (sensors) continue to release NO, even at low levels, the inflammatory cell infiltration and resulting collagen density are lessened. While these studies strongly support the benefits of NO release in mitigating the FBR, the mechanisms through which exogenous NO acts on the surrounding tissue, especially under the condition of hyperglycemia, remain vague. Such knowledge would inform strategies to refine appropriate NO dosage and release kinetics for optimal therapeutic activity. In this study, we evaluated mediator, immune cell, and mRNA expression profiles in the local tissue microenvironment surrounding implanted sensors as a function of NO release, diabetes, and implantation duration. A custom porcine wound healing-centric multiplex gene array was developed for nanoString barcoding analysis. Tissues adjacent to sensors with sustained NO release abrogated the implant-induced acute and chronic FBR through modulation of the tissue-specific immune chemokine and cytokine microenvironment, resulting in decreased cellular recruitment, proliferation, and activation at both the acute (7-d) and chronic (14-d) phases of the FBR. Further, we found that sustained NO release abrogated the implant-induced acute and chronic foreign body response through modulation of mRNA encoding for key immunological signaling molecules and pathways, including STAT1 and multiple STAT1 targets including MAPK14, IRAK4, MMP2, and CXCL10. The condition of diabetes promoted a more robust FBR to the implants, which was also controlled by sustained NO release

    Plant growth-promoting microorganisms as biocontrol agents of plant diseases: Mechanisms, challenges and future perspectives

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    Plant diseases and pests are risk factors that threaten global food security. Excessive chemical pesticide applications are commonly used to reduce the effects of plant diseases caused by bacterial and fungal pathogens. A major concern, as we strive toward more sustainable agriculture, is to increase crop yields for the increasing population. Microbial biological control agents (MBCAs) have proved their efficacy to be a green strategy to manage plant diseases, stimulate plant growth and performance, and increase yield. Besides their role in growth enhancement, plant growth-promoting rhizobacteria/fungi (PGPR/PGPF) could suppress plant diseases by producing inhibitory chemicals and inducing immune responses in plants against phytopathogens. As biofertilizers and biopesticides, PGPR and PGPF are considered as feasible, attractive economic approach for sustainable agriculture; thus, resulting in a “win-win” situation. Several PGPR and PGPF strains have been identified as effective BCAs under environmentally controlled conditions. In general, any MBCA must overcome certain challenges before it can be registered or widely utilized to control diseases/pests. Successful MBCAs offer a practical solution to improve greenhouse crop performance with reduced fertilizer inputs and chemical pesticide applications. This current review aims to fill the gap in the current knowledge of plant growth-promoting microorganisms (PGPM), provide attention about the scientific basis for policy development, and recommend further research related to the applications of PGPM used for commercial purposes

    Promising prospective effects of Withania somnifera on broiler performance and carcass characteristics: A comprehensive review

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    Poultry production contributes markedly to bridging the global food gap. Many nations have limited the use of antibiotics as growth promoters due to increasing bacterial antibiotic tolerance/resistance, as well as the presence of antibiotic residues in edible tissues of the birds. Consequently, the world is turning to use natural alternatives to improve birds' productivity and immunity. Withania somnifera, commonly known as ashwagandha or winter cherry, is abundant in many countries of the world and is considered a potent medicinal herb because of its distinct chemical, medicinal, biological, and physiological properties. This plant exhibits antioxidant, cardioprotective, immunomodulatory, anti-aging, neuroprotective, antidiabetic, antimicrobial, antistress, antitumor, hepatoprotective, and growth-promoting activities. In poultry, dietary inclusion of W. somnifera revealed promising results in improving feed intake, body weight gain, feed efficiency, and feed conversion ratio, as well as reducing mortality, increasing livability, increasing disease resistance, reducing stress impacts, and maintaining health of the birds. This review sheds light on the distribution, chemical structure, and biological effects of W. somnifera and its impacts on poultry productivity, livability, carcass characteristics, meat quality, blood parameters, immune response, and economic efficiency

    Large-scale pharmacogenomic study of sulfonylureas and the QT, JT and QRS intervals: CHARGE Pharmacogenomics Working Group

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    Sulfonylureas, a commonly used class of medication used to treat type 2 diabetes, have been associated with an increased risk of cardiovascular disease. Their effects on QT interval duration and related electrocardiographic phenotypes are potential mechanisms for this adverse effect. In 11 ethnically diverse cohorts that included 71 857 European, African-American and Hispanic/Latino ancestry individuals with repeated measures of medication use and electrocardiogram (ECG) measurements, we conducted a pharmacogenomic genome-wide association study of sulfonylurea use and three ECG phenotypes: QT, JT and QRS intervals. In ancestry-specific meta-analyses, eight novel pharmacogenomic loci met the threshold for genome-wide significance (P&lt;5 × 10−8), and a pharmacokinetic variant in CYP2C9 (rs1057910) that has been associated with sulfonylurea-related treatment effects and other adverse drug reactions in previous studies was replicated. Additional research is needed to replicate the novel findings and to understand their biological basis
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