574 research outputs found
The Quark-Gluon Plasma Equation of State and The Generalized Uncertainty Principle
The quark-gluon plasma (QGP) equation of state within a minimal length
scenario or Generalized Uncertainty Principle (GUP) is studied. The Generalized
Uncertainty Principle is implemented on deriving the thermodynamics of ideal
QGP at a vanishing chemical potential. We find a significant effect for the GUP
term. The main features of QCD lattice results were quantitatively achieved in
case of , and flavors for the energy density,
the pressure and the interaction measure. The exciting point is the large value
of bag pressure especially in case of flavor which reflects the
strong correlation between quarks in this bag which is already expected. One
can notice that, the asymptotic behavior which is characterized by
Stephan-Boltzmann limit would be satisfied.Comment: 9 Pages, 8 figure
Floristic analysis and biogeography of Tubiflorae in Egypt
The species distribution and biogeography of the Egyptian Tubiflorae were exam-ined in detail. We found 284 species of vascular plants belonging to 96 genera and 12 families, making the Egyptian Tubiflorae richer in species than that of other arid region floras: Libya and Saudi Arabia. The most species rich families were Scrophulariaceae, Boraginaceae, Labiatae, Convolvulaceae and Solanaceae, constituting more than 85% of the totál species in the order. The generic spectrum dominated by a suite of species-rich genera (Convolvulus, Heliotropium, Veronica, Solanum, Salvia, Cuscuta, Echium, Ipomoea and Orobanche). Therophytes were the most dominant life forms among the families, followed by chamaephytes and hemicryptophytes. Boraginaceae and Scrophulariaceae had the highest share of annuals. Remarkable distribution patterns of the life forms in the seven studied biogeographic zones were noticed. Trees were dominant in the Mediterranean zone, while shrubs, perennial herbs and therophytes were dominant in the Sinai. Altogether 8 endemic species and 14 near-endemics were included in the Tubiflorae of Egypt; mostly from Southern Sinai. We found that Labiatae and Scrophulariaceae were the families with higher concentration of endemics. Notably, Teucrium was among the genera of the Mediterranean Africa with highest endemism. Gamma diversity varied from 171 in the Sinai Peninsula to 43 and 39 in the Oases of the western Desert and along the Red Sea, respectively. Interestingly, highest significant values of similarity and species turnover (béta diversity) were observed between the Oases and the Nile lands. It is worthy noting the com-bined effect of both temperature and precipitation on gamma diversity of Tubiflorae in the 7 biogeographic zones. Our results indicated that almost one-half of the species showed a certain degree of consistency, i.e., with narrow geographic expansion. On the basis of UPGMA clustering and PCoA analysis, 4 floristic groups were recognized, each include one or more biogeographic zone. The occurrence of the species of Tubiflorae in the adjacent régiónál arid floras and their phytochorological afflnities, were discussed
Drinking water quality evaluation of hand pumping wells using water quality index and standard algal toxicity testing in Mansoura and Talkha cities, Egypt
تم اختيار ستة مضخات منزلية حبشية موزعة على قرى مختلفة من مدينتي المنصورة (Mans-I, Mans-II, Mans-III) وطلخا (Talk-I, Talk-II, Talk-III)،مصر ، لتقييم جودة المياه خلال عام 2017. تم جمع عينات المياه خلال منتصف الفصول الأربعة وهي الشتاء والربيع والصيف والخريف. تم استخدام أدوات التقييم القياسية لتقييم جودة المياه اشتملت علىدالة جودة المياه (WQI) ، واختبار الطحالب القياسي للسمية.أوضحت نتائجWQI اختلافات موقعية وموسمية ملحوظة مع جودة مياه ممتازه (WQI =90) وجيدة (WQI, 70 -89) مسجلة فقط لعينات المياه التي تم جمعها من مضخة Mans-I الموجودة في منطقة قليلة السكان وعلى بعد 50 مترًا فقط من الفرع الشرقي (دمياط) من نهر النيل. أظهرت قيمWQI للمضخات الأخرى الموجودة في المناطق المكتظة بالسكان وعلى بعد كيلومترات من فرع النيل جودة مياه متوسطة (WQI, 50-69) أو سيئة (WQI, 25-49) حسب موسم أخذ العينات والموقع. جميع عينات المياه التي تم جمعها من مضخة Mans-I كانت غير سامة دون أي آثار مثبطة على نمو طحلب الاختبار القياسيPseudokirchneriella subcapitata. أظهرت عينات المياه المحمعة من جميع المضخات الأخرى تأثيرات سامة واضحة على نمو طحالب الاختبار مع قيم السمية(EC50) متفاوتة تتراوح بين15.8 %و 83 %.. الخلاصة ، كانت جميع عينات المياه التي تم جمعها من مضخة Mans-I آمنة للصحة بينماالعينات التي تم جمعها من مضخات أخرى يمكن أن تشكل مخاطر كبيرة على صحة الإنسان إذا استخدمت للشرب.Six house-hold Abyssinian pumps distributed in different villages of Mansoura (Mans-I, Mans-II and Mans-III) and Talkha (Talk-I, Talk-II and Talk-III) cities, Egypt, have been selected for regular seasonal water quality assessment during 2017. Water samples have been collected within the mid-periods of four seasons Standard assessment tools were employed for the integrated water quality assessment including Water Quality Index (WQI) and ISO standard algal toxicity test. WQI displayed remarkable local and seasonal variations with excellent (≥ 90) and good (70 - 89) only recorded for water samples collected from Mans-I pump located in sparsely populated area and far 50 meters only from the eastern (Damietta) branch of Nile River. WQI of other pumps located in densely populated areas and far kilometers from the Nile branch indicated either medium (50-69) or bad (25-49) quality depending on sampling season and sampling site location. All water samples collected from the pump Mans-I were non toxic without any inhibitory effects on the growth of the standard test alga Pseudokirchneriella subcapitata. Water samples from all other pumps, however, showed obvious toxic effects on test algae growth with varying EC50 values ranged between15.8% and 83%, depending on water sample and the sampling season. Concisely, all water samples collected from Mans-I pump were health safe with acceptable drinking water guidelines while samples collected from other pumps can impose great human health risks if used for drinkin
Dihydrochalcone glycosides from Oxytropis myriophylla
Chemical investigations of the 70% alcohol extract of Oxytropis myriophylla (Pall.) DC. (Leguminosae) have afforded the new natural product neohesperidin dihydrochalcone (1) and the known phloretin-4'-O-β-D-glucopyranoside (2), which was the first reported from the genus Oxytropis. This paper reports the isolation and full spectroscopic characterization of compounds 1 and 2 by NMR, UV, IR and MS data
Evaluation of Groundwater for Arsenic Contamination Using Hydrogeochemical Properties and Multivariate Statistical Methods in Saudi Arabia
The aim of this research is to evaluate arsenic distribution and associated hydrogeochemical parameters in 27 randomly selected boreholes representing aquifers in the Al-Kharj geothermal fields of Saudi Arabia. Arsenic was detected at all sites, with 92.5% of boreholes yielding concentrations above the WHO permissible limit of 10 μg/L. The maximum concentration recorded was 122 μg/L (SD = 29 μg/L skewness = 1.87). The groundwater types were mainly Ca+2-Mg+2-SO4-2-Cl− and Na+-Cl−-SO4-2, accounting for 67% of the total composition. Principal component analysis (PCA) showed that the main source of arsenic release was geothermal in nature and was linked to processes similar to those involved in the release of boron. The PCA yielded five components, which accounted for 44.1%, 17.0%, 10.1%, 08.4%, and 06.5% of the total variance. The first component had positive loadings for arsenic and boron along with other hydrogeochemical parameters, indicating the primary sources of As mobilization are derived from regional geothermal systems and weathering of minerals. The remaining principal components indicated reductive dissolution of iron oxyhydroxides as a possible mechanism. Spatial evaluation of the PCA results indicated that this secondary mechanism of arsenic mobilization may be active and correlates positively with total organic carbon. The aquifers were found to be contaminated to a high degree with organic carbon ranging from 0.57 mg/L to 21.42 mg/L and showed high concentrations of NO3- ranging from 8.05 mg/L to 248.2 mg/L
Effect of Denture Base Reinforcement Using Light Cured E- Glass Fibers on the Level of Salivary Immunoglobulin A
BACKGROUND: A gap still exists between in vitro and clinical studies concerning the biocompatibility of the material in the oral environment and their potential to cause immunological undesirable side effects. The uses of glass fibres to improve the mechanical properties of acrylic resin denture base polymers are well documented in vitro.
AIM: The present study aimed to evaluate the effect of denture base reinforcement using light-cured E- glass fibres mesh on the level of salivary immunoglobulin A (S-IgA) in patients wearing complete dentures.
MATERIAL AND METHODS: Fourteen completely edentulous patients, in need of complete dentures, participated in the study. The patients were divided into two groups (n = 7) according to the treatment protocol. In the first group, patients received conventional heat-cured acrylic resin dentures. In the second group, the mandibular dentures were reinforced using light cured resin impregnated E glass fibres mesh. In both groups, salivary samples were collected using passive drool technique. The level IgA was assessed by enzyme-linked immunosorbent assay (ELISA) technique at different time intervals. Statistical analysis was carried out using one-way ANOVA followed by Tukey`s post-hoc test and independent t-test. The significant level was set at P ≤ 0.05.
RESULTS: Acrylic resin dentures and reinforced ones demonstrated an increase in the mean values of IgA level at the end of the follow-up intervals. And this increase was statistically significant (P ≤ 0.05). Although, the reinforced dentures revealed higher mean values, there was no statistically significant difference between the two groups (P > 0.05)
CONCLUSIONS: Within the limitations of the present study, the following could be concluded: (1) the insertion of complete dentures induced changes in the level of IgA; and (2) denture base reinforcement using light cured resin impregnated E-glass fibres mesh had a similar effect to that of heat cured acrylic resin on the level of IgA
Prognostic Exploration of U-F-Au-Mo-W Younger Granites for Geochemical Pathfinders, Genetic Affiliations, and Tectonic Setting in El-Erediya-El-Missikat Province, Eastern Desert, Egypt
Younger granite bodies form two arches, the western and the eastern (WA, EA), which extend from the south northwards from the Meatique, ophiolitic group-island arc rocks, to the large older granite outcrop to the north. This paper concerns the feasibility of exploration in the El-Erediya-Ria El-Garah-El-Gidami-El-Missikat Y Gr regions. Fieldwork and remote sensing, together with geochemical, petrochemical, and mineralogical studies, are used to show the controlling factors, routes, and the origins of the deposits. Remote sensing is used to delineate the different rock units. Normal and strike–slip NW, NNE faults, veins, fractured ENE shear zones, and alteration zones of magmatic-hydrothermal fluids are discussed. Granites are considered using petrochemical diagrams as resources. These rocks are categorized as syeno-and alkali feldspar granites. Geochemical binary relationships recognized the granites are highly fractionated calc-alkaline-altered Monzo-, syeno-, and alkali feldspar granites formed in the active continental margin. The observed positive Ga vs. Cu, Zn, and Ni correlations are used for epithermal-magmatic-hydrothermal polymetallic veins and mineralized greisen zones. Negative Cu vs. Mo correlation patterns show probable Mo-porphyry deposits in the deeper zones at the contact point between porphyritic perthite and perthite granitic El-Erediya mass. The Zr/Sr between 1.65 to 2.93 plus fluorites in El-Missikat and up to 5.48 plus fluorites in El-Erediya show both U-poor at El-Missikat and U-rich deposits at El-Erediya. The recorded U, Th, Cu, and Pb vertical zoning sequence of deposition differentiates U aureole and deposit zones. The estimated lateral zoning sequences of deposition of these elements define the centers of U deposits. Pathfinders for the deposit of the examined area include the positive Fe2 O3 vs. Mg O and Fe2 O3 vs. Ca O correlations, and also negative Rb/Sr vs. K/Na and Rb vs. Sr ones, can be applied to future prospecting for similar U-F-Au-W-Mo deposits in the Eastern Desert of Egypt. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
Redox linked flavin sites in extracellular decaheme proteins involved in microbe-mineral electron transfer
Extracellular microbe-mineral electron transfer is a major driving force for the oxidation of organic carbon in many subsurface environments. Extracellular multi-heme cytochromes of the Shewenella genus play a major role in this process but the mechanism of electron exchange at the interface between cytochrome and acceptor is widely debated. The 1.8 Å x-ray crystal structure of the decaheme MtrC revealed a highly conserved CX8C disulfide that, when substituted for AX8A, severely compromised the ability of S. oneidensis to grow under aerobic conditions. Reductive cleavage of the disulfide in the presence of flavin mononucleotide (FMN) resulted in the reversible formation of a stable flavocytochrome. Similar results were also observed with other decaheme cytochromes, OmcA, MtrF and UndA. The data suggest that these decaheme cytochromes can transition between highly reactive flavocytochromes or less reactive cytochromes, and that this transition is controlled by a redox active disulfide that responds to the presence of oxygen
On the fourth-order accurate compact ADI scheme for solving the unsteady Nonlinear Coupled Burgers' Equations
The two-dimensional unsteady coupled Burgers' equations with moderate to
severe gradients, are solved numerically using higher-order accurate finite
difference schemes; namely the fourth-order accurate compact ADI scheme, and
the fourth-order accurate Du Fort Frankel scheme. The question of numerical
stability and convergence are presented. Comparisons are made between the
present schemes in terms of accuracy and computational efficiency for solving
problems with severe internal and boundary gradients. The present study shows
that the fourth-order compact ADI scheme is stable and efficient
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