114 research outputs found

    Estrateriga de dispersión de plantas en diferentes hábitats ecológicos de los Emiratos Árabes Unidos

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    Fecha de lectura de Tesis Doctoral: 18 de enero 2019Biología Vegetal (Botánica y Fisiología Vegetal) Resumen tesis: Estudio de las estrategias de dispersion de las especies vegetales en diferentes habitats del desierto de los Emiratos Arabes Unidos. Se estudian las estrategias de dispersion de 307 especies y se relacionan con los principales caracteres funcionales relacionados con la supervivencia de especies en cinco ecosistemas aridos -deserticos. Se estudia la relacion entre la forma de crecimiento de las especies vegetales y la presencia de baco aereo de semillas. Se estudia el efecto de los regimenes de luz y temperatura que intervien en la dormancia y germinacion de Citrulus colocynthis, especie clave en el desierto de Arabi

    Performance of Isolated Footing with Several Corrosion Levels under Axial Loading

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    This research aims to illustrate the corrosion process and its effect on the deterioration of reinforced concrete (RC) isolated footings using a small-scale model (1/8) and present the results of a prototype-scale study using a numerical model with different concrete depths and corrosion levels under axial load. The experimental program consisted of testing five small-scale (1/8) model RC isolated footings under axial loading after subjecting them to accelerated corrosion tests with a constant current. The main variable in the small-scale sample test was the corrosion level. This study presents an experimental approach, using the constant current method and the finite element method (FEM) with the ABAQUS package, to examine its effect on the axial load behavior under different corrosion ratios, which were 0%, 4.21%, 9.11%, 24.56%, and 30.67%. On the prototype scale, the variables were the corrosion level and the RC depths of 300 mm, 400 mm, and 500 mm. The results indicated that the average deviation in ultimate load between the experimental and FEM outcomes for the small-scale was below 5.6%, while the average deflection deviation was 6.8%. Also, the study found that an increase in the depth of the RC footing and corrosion ratio led to a more pronounced impact of the cracking pattern in the concrete and corroded bars, as well as a greater difference in the failure load. The experimental results suggest that the proposed numerical model is accurate and effective. These findings have important implications for the evaluation of isolated footings affected by corrosion damage using FEM, and can help inform decisions related to their design and maintenance. The failure loads of non-corroded footings with different depths were compared with the ECP-203 provisions of the 2018 Egyptian Code, and how corrosion ratios can be simulated by numerical models. The percentage variation between the design loads by code and the numerical loads by ABAQUS for controlled footings with thicknesses of 300, 400, and 500 mm was found to be 73%, 80%, and 78%, respectively. Using the derived relationship, the equivalent corrosion ratio percentages were 23.8%, 20.2%, and 32%, respectively. Doi: 10.28991/CEJ-2023-09-06-011 Full Text: PD

    Resonance Two Photon Ionization Study of Binary Clusters of Styrene with Polar Molecules

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    One-color resonance two-photo ionization (R2PI) spectra of mixed clusters of styrene molecule (S) with polar molecules [water (W), methanol (M), ethanol (E), and trifuoroethanol (T)] were measured through the S1←S0 transition of the styrene molecule. The spectra reveal a rapid increase in complexity with the number of polar molecules in the cluster, associated with van der Waal modes and isomeric forms. The spectral shifts of the cluster origins from the S1-S0 transition of the bare styrene molecule reflect the nature of the intermolecular interactions within the binary clusters. The obtained R2PI spectra xv were compared with the spectra of the analogous benzene containing clusters. The styrene-water and the styrene-methanol complexes exhibited very different spectral shifts and structures as compared to the benzene-water and benzene-methanol complexes, respectively. The favorable interactions of polar molecules with the olefin group of styrene may explain the strong inhibition effects of exerted by small concentrations of water and alcohols on the cationic polymerization of styrene. Size-specified intracluster proton transfer reactions were observed for mixed clusters of styrene dimer with water, methanol and ethanol molecules. It was proposed that the polar molecules tend to aggregate around the olefin center, which promotes the transfer of the charge from the propagating chain to the hydrogen-bonded polar molecules subcluster. The minimum number of polar molecules required for a proton transfer to take place exothermically depends on the proton affinity of the polar molecules subcluster. The estimated upper limit value for the proton affinity of styrene dimer radical was evaluated based on the energetic of the proton transfer reaction to be ≤ 220.4 kcal/mol. No intracluster reaction was observed for styrene-trifluoroethanol (STn) system. In order to provide a comparison between the styrene and benzene systems, the benzene-ethanol (BEn) and benzene-trifluoroethanol (BTn) clusters were studied by using the R2PI technique via the 6¹0 transition of the benzene molecule. Both dissociative electron transfer and dissociative proton transfer reactions were observed within the BEn clusters, where n = 2 and 3, respectively. Proton transfer reactions were observed following dissociative electron transfer reactions within the (BTn) clusters, where n = 4, to generate the protonated clusters (H+Tn)

    Overview on Hepatitis B vaccination

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    Background: Hepatitis B virus (HBV) infection is increasing globally, posing a serious public health problem. Hepatitis B virus (HBV) infection and mortality are among the leading causes of death worldwide. Concerns for public health are amplified by the fact that about a third of the world's population is afflicted with HBV. HBV infection may result in cirrhosis, hepatocellular cancer, or both (HCC).Immunization is the most cost-effective strategy available worldwide for controlling and preventing hepatitis B in terms of benefit-cost ratio. Objective: This review article discusses the most critical components of the HBV vaccine and the most efficient strategies for increasing HBV vaccinatio

    Minimally Invasive Approach in Surgical Management of Renal Neoplasms National Cancer Institute Experience

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    BACKGROUND: Minimally invasive nephrectomy is considered a technically challenging procedure requiring a long learning curve to reach acceptable warm ischemia time and perioperative complications. These minimally invasive techniques result in a shorter hospital stay and less post-operative pain. AIM: This study aims to demonstrate the National Cancer Institute experience regarding the benefits of laparoscopic and robot-assisted nephrectomy over open technique. METHODS: This is a retrospective descriptive cohort study including 62 patients with renal masses treated with nephrectomy whether partial, total or radical, 26 cases were treated by minimally invasive techniques (8 robotic and 18 laparoscopic), while 36 cases were treated by open technique. Inclusion criteria were patients between 20 and 70 years with renal neoplasm without renal vein thrombosis, with tumor stage T1 or T2 N0 M0. Exclusion criteria were patients with medical comorbidities that preclude surgical management or minimally invasive techniques and patients refusing surgery in general. RESULTS: Minimally invasive nephrectomy resulted in shorter hospital stay (mean hospital stay was 2.2 days for the minimally invasive group and 3.6 days for the open group) and less post-operative pain than open technique (p < 0.001 and = 0.002, respectively), while open technique resulted in shorter operation time (p = 0.039, mean operation time 147.8 min compared to 184.8 in the minimally invasive group). CONCLUSION: Minimally invasive nephrectomy (laparoscopic and robotic) resulted in less post-operative pain and shorter hospital stay compared to open technique despite consuming longer operation time which may be decreased by improving the learning curve of operating surgeons

    Survival rate in acute kidney injury superimposed COVID-19 patients: a systematic review and meta-analysis

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155406/1/Yessayan_Survival_Rate.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155406/4/COVID YESSAYAN DeepBluepermissions_agreement-CCBYandCCBY-NC_ORCID.docxDescription of Yessayan_Survival_Rate.pdf : ArticleDescription of COVID YESSAYAN DeepBluepermissions_agreement-CCBYandCCBY-NC_ORCID.docx : Deep Blue Sharing Agreemen

    Characterization and classification of the microporosity in the unconventional carbonate reservoirs: A case study from Hanifa Formation, Jafurah Basin, Saudi Arabia

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    Formation porosity is a key factor that exerts substantial control upon reserve estimates, and ultimately may affect the development viability of unconventional resources. Microporosity studies have largely focused on siliciclastic mudstones, with limited examples that assess porosity type and distribution in organic-rich calcareous mudstone successions. In this work, a comprehensive porosity characterization study was performed on the organic-rich carbonate-dominated Hanifa Formation of the Jafurah Basin, which is the largest unconventional basin in Saudi Arabia. An extensive experimental program, involving petrographical description, SEM analysis, mineralogical analysis using XRD and QEMSCAN, and geochemistry analysis was employed in order to characterize the samples and analyze the geological origins of the microporosity. The main constituent minerals in this study are calcite (87 wt%) and anhydrite (9 wt%), as well as 85%. Fundamentally, the findings of this study demonstrate that the Hanifa Formation in the Jafurah Basin has the potential for gas exploration and recovery

    Novel quinazoline-based sulfonamide derivative (3D) induces apoptosis in colorectal cancer by inhibiting JAK2–STAT3 pathway

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    Introduction: Colorectal cancer (CRC) is a major worldwide health problem owing to its high prevalence and mortality rate. Developments in screening, prevention, biomarker, personalized therapies and chemotherapy have improved detection and treatment. However, despite these advances, many patients with advanced metastatic tumors still succumb to the disease. New anticancer agents are needed for treating advanced stage CRC as most of the deaths occur due to cancer metastasis. A recently developed novel sulfonamide derivative 4-((2-(4-(dimethylamino) phenyl)quinazolin-4-yl)amino)benzenesulfonamide (3D) has shown potent antitumor effect; however, the mechanism underlying the antitumor effect remains unknown. Materials and methods: 3D-mediated inhibition on cell viability was evaluated by MTT and real-time cell proliferation was measured by xCelligence RTDP instrument. Western blotting was used to measure pro-apoptotic, anti-apoptotic proteins and JAK2-STAT3 phosphorylation. Flow cytometry was used to measure ROS production and apoptosis. Results: Our study revealed that 3D treatment significantly reduced the viability of human CRC cells HT-29 and SW620. Furthermore, 3D treatment induced the generation of reactive oxygen species (ROS) in human CRC cells. Confirming our observation, N-acetylcysteine significantly inhibited apoptosis. This is further evidenced by the induction of p53 and Bax; release of cytochrome c; activation of caspase-9, caspase-7 and caspase-3; and cleavage of PARP in 3D-treated cells. This compound was found to have a significant effect on the inhibition of antiapoptotic proteins Bcl2 and BclxL. The results further demonstrate that 3D inhibits JAK2–STAT3 pathway by decreasing the constitutive and IL-6-induced phosphorylation of STAT3. 3D also decreases STAT3 target genes such as cyclin D1 and survivin. Furthermore, a combination study of 3D with doxorubicin (Dox) also showed more potent effects than single treatment of Dox in the inhibition of cell viability. Conclusion: Taken together, these findings indicate that 3D induces ROS-mediated apoptosis and inhibits JAK2–STAT3 signaling in CRC

    Non-penetrating deep sclerectomy versus combined trabeculotomy–trabeculectomy in primary congenital glaucoma

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    Background: The primary mode of therapy in children with primary congenital glaucoma (PCG) and mild or no corneal edema is goniotomy, which has a high success rate. However, in developing countries, the diagnosis of PCG is usually delayed, and corneal cloudiness interferes with goniotomy. Therefore, trabeculotomy may be the best choice in such eyes. We compared the short-term efficacy and safety of primary combined trabeculotomy–trabeculectomy (primary CTT) with that of non-penetrating deep sclerectomy (NPDS) in managing PCG. Methods: This prospective, randomized, comparative study included patients with PCG referred to Al-Azhar University Hospitals within a 1-year period. Eyes were randomly allocated to one of two groups: eyes in NPDS group underwent NPDS, and those in primary CTT group underwent primary CTT. Baseline and frequent postoperative assessments of intraocular pressure (IOP), cup-to-disc ratio (C/D ratio), corneal diameter, and axial length were performed for up to 6 months. The success rates were recorded in both groups. Results: Forty eyes of 26 patients were included, with 20 eyes allocated to each group. The mean (standard deviation) age of all patients was 12.9 (9.5) months, with comparable ages and sex ratios between groups (both P > 0.05). Both groups demonstrated a significant reduction in IOP and C/D ratio at each postoperative visit compared to the baseline visit (all P < 0.001), with no significant difference detected between the groups (all P > 0.05), except for a significantly lower IOP in NPDS group at 1 month (P < 0.05). The corneal diameter and axial length were comparable between groups at baseline and remained unchanged at all postoperative visits (all P > 0.05). The groups had comparable success rates (P > 0.05). No serious complications were detected. Conclusions: CTT and NPDS both yielded reasonable IOP control and reversal of cupping in eyes with PCG. We observed equal effectiveness of the surgical procedures without major safety concerns. Further large-scale clinical trials with longer follow-up periods are needed to verify our preliminary findings

    Aflibercept or ranibizumab for diabetic macular edema

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    Background: Vascular endothelial growth factor (VEGF) is the primary substance involved in retinal barrier breach. VEGF overexpression may cause diabetic macular edema (DME). Laser photocoagulation of the macula is the standard treatment for DME; however, recently, intravitreal anti-VEGF injections have surpassed laser treatment. Our aim was to evaluate the efficacy of intravitreal injections of aflibercept or ranibizumab for managing treatment-naive DME.   Methods: This single-center, retrospective, interventional, comparative study included eyes with visual impairment due to treatment-naive DME that underwent intravitreal injection of either aflibercept 2 mg/0.05 mL or ranibizumab 0.5 mg/0.05 mL at Al-Azhar University Hospitals, Egypt between March 2023 and January 2024. Demographic data and full ophthalmological examination results at baseline and 1, 3, and 6 months post-injection were collected, including the best-corrected distance visual acuity (BCDVA) in logarithm of the minimum angle of resolution (logMAR) notation, slit-lamp biomicroscopy, dilated fundoscopy, and central subfield thickness (CST) measured using spectral-domain optical coherence tomography.   Results: Overall, the 96 eyes of 96 patients with a median (interquartile range [IQR]) age of 57 (10) (range: 20–74) years and a male-to-female ratio of 1:2.7 were allocated to one of two groups with comparable age, sex, diabetes mellitus duration, and presence of other comorbidities (all P >0.05). There was no statistically significant difference in baseline diabetic retinopathy status or DME type between groups (both P >0.05). In both groups, the median (IQR) BCDVA significantly improved from 0.7 (0.8) logMAR at baseline to 0.4 (0.1) logMAR at 6 months post-injection (both P = 0.001), with no statistically significant difference between groups at all follow-up visits (all P >0.05). The median (IQR) CST significantly decreased in the aflibercept group from 347 (166) µm at baseline to 180 (233) µm at 6 months post-injection, and it decreased in the ranibizumab group from 360 (180) µm at baseline to 190 (224) µm at 6 months post-injection (both P = 0.001), with no statistically significant differences between groups at all follow-up visits (all P >0.05). No serious adverse effects were documented in either group.   Conclusions: Ranibizumab and aflibercept were equally effective in achieving the desired anatomical and functional results in patients with treatment-naive DME in short-term follow-up without significant differences in injection counts between both drugs. Larger prospective, randomized, double-blinded trials with longer follow-up periods are needed to confirm our preliminary results.&nbsp
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