198 research outputs found
Green synthesis of nano binary oxide SiO2/V2O5 NPs integrated ointment cream application on wound dressings and skin cancer cells
اشتملت الدراسة الحالية على تحضير المزدوج النانو SiO2/V2O5 باستخدام مواد طبيعية خام كمادة أولية حيث استخدمت رماد قشور الارز بعد حرقها بدرجة °C700 سيليزية للتخلص من المواد العضوية واللاعضوية في القشور حيث كانت هي المادة الخام لاستخلاص السليكا جل والتي تم مزجها مع أوكسيد الفناديوم الخماسي وتم تشخيص المزدوج النانو SiO2/V2O5 المحضر باستخدام عدة تقنيات مثل الأشعة السينية ,المجهر الالكتروني الماسح عالي الدقة حيث تم حساب معدل الحجم الحبيبي باستخدام صورة المجهر الالكتروني الماسح للسطح المادة المحضرة عند المقياس 200 نانومتر , مطيافية تشتت الطاقة بالأشعة السينية التي استخدمت لكشف تركيز العناصر الموجودة في النموذج المحضر SiO2/V2O5 من مادة قشور الارز الخام وتقديرها كميا ونوعيا وكذلك تم قياس المساحة السطحية للسليكا المستخلص والمزدوج المحضر SiO2/V2O5 والمقارنة بينهما كما موضح في النتائج كما تضمنت الدراسة البحثية الفعالية البيولوجية للمزدوج SiO2/V2O5 وتأثيرها على تثبيط النمو البكتيري بعد أن تم تطبيق المادة النانوية المحضرة على ضمادات الجروح حيث أعطت نتيجة واعدة لاستخدامها كضمادات موضعية تعمل على إزالة الميكروبات وخاصة لمرضى الحروق والجروح وذلك بسبب فعاليتها العالية لقتل البكتيريا الموجبة S.aurea عند تركيزµg/mL 625 التي تتميز بمقاومتها للعديد من المضادات الحيوية . تعتبر مقاومة المضادات الحيوية من المشكلات التي يسعى العديد من الباحثين لحل هذه المشكلة من خلال توفير مضادات حيوية أكثر فعالية وأمانًا. اختيار مادة السيليكا المستخلصة من مادة طبيعية لتقليل السمية الناتجة عن استخدام الكيماويات ، حيث تعتبرالسيليكا مادة غير سامة. لذلك ، أثناء التحضير ، تم الحرص على استخدام المواد الكيميائية بتراكيز منخفضة لتقليل السمية. تم دراسة التأثيرات السامة للخلايا في المختبر SiO2 / V2O5)) NPs على خط الخلايا الطبيعية Vero 101 وخط خلايا الجلد A431 وتم فحصهما بتراكيز مختلفة. تم استخدام MTT (3- (4،5-dimethylthiazol-2-yl) -2،5-diphenyltetrazolium bromide) لتحديد التأثيرات السامة للخلايا للمساحيق النانوية الخضراء المُصنّعة.Green synthesis is depending on preparation of nano composited SiO2/V2O5 by using the modified sol-gel method depending on rice husk ash as a source for the extraction of silica gel and the product powder of nano composited SiO2/V2O5 characterization by many techniques such as X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FESEM), and N2 adsorptions/desorption isotherms (BET). This study also includs the biological effectiveness of SiO2/V2O5 and its effect on inhibiting bacterial growth after the prepared nanomaterial was applied to wound dressings, which gave a promising result for its use as topical dressings that remove microbes especially for burns and wounds patients, due to its high effectiveness in killing Gram-positive bacteria S.aurea positive bacteria at a concentration of 625 µg/mL, which is characterized by its resistance to many antibiotics. Antibiotic resistance is one of the problems that many researchers seek to solve this problem by providing more effective and safe antibiotics. Choosing silica extracted from a natural substance to reduce the toxicity resulting from the use of chemicals, as silica oxide is considered a non-toxic substance. Therefore, during preparation, care was taken to use chemicals in low concentrations to reduce toxicity. In vitro cytotoxic effects were studied of composited SiO2/V2O5 nanoparticles on Vero cell line 101 and skin cell line-A431were investigated at different concentrations. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to determine the cytotoxic effects of green synthesized nanopowders
Simulation Study of Adrenaline Synthesis from Phenylalanine
      Simulation study of Adrenaline synthesis from Phenylalanine has been carried out using semi-empirical methods (PM3) and density functional theory (DFT) STO-3G level of theory . Geometrical properties and vibration mods have been calculated for all structures. Different probable products have been suggested for each reaction and the most probable products being selected depending upon the electronic properties to prove the pathway of reactions that’s needed to synthesis adrenaline in the human body.          The calculations show the most probable product than other structurs due its energetic values of total energy, energy barrier value, heat of formation, zero point energy, imaginary frequency and rate constant that’s equal to (5.554*1012, 5.572*1012, 7.857*1012, 1.331*1013,1.116*1013) respectively by s-1 units. Thermodynamic functions (∆H, ∆S, ∆G) have been calculated for five steps reactions of Adrenaline synthesis . In reaction 1 equal to (-69.468, 1.37*10-4, -66.610), reaction 2 (-46.453, 3.044*10-3, -64.710), reaction 3 (-63.734, 0.022, 138.900), reaction 4 (87.036, 8.631*10-3, -451.510) and reaction 5 (-6.722,-0.025, 346,800) respectively by kCal/mol, kCal/mol/deg, and kCal/mol respective units. The chemical reactivity or energy gap has been calculated for the most probable products in the pathway of adrenaline synthesis
Solute channels of the outer membrane: from bacteria to chloroplasts
Chloroplasts, unique organelles of plants, originated from endosymbiosis of an ancestor of today's cyanobacteria with a mitochondria-containing host cell. It is assumed that the outer envelope membrane, which delimits the chloroplast from the surrounding cytosol, was thus inherited from its Gram-negative bacterial ancestor. This plastid-specific membrane is thus equipped with elements of prokaryotic and eukaryotic origin. In particular, the membrane-intrinsic outer envelope proteins (OEPs) form solute channels with properties reminiscent of porins and channels in the bacterial outer membrane. OEP channels are characterised by distinct specificities for metabolites and a quite peculiar expression pattern in specialised plant organs and plastids, thus disproving the assumption that the outer envelope is a non-specific molecular sieve. The same is true for the outer membrane of Gram-negative bacteria, which functions as a permeability barrier in addition to the cytoplasmic membrane, and embeds different classes of channel pores. The channels of these prokaryotic prototype proteins, ranging from unspecific porins to specific channels to ligand-gated receptors, are exclusively built of P-barrels. Although most of the OEP channels are formed by P-strands as well, phylogeny based on sequence homology alone is not feasible. Thus, the comparison of structural and functional properties of chloroplast outer envelope and bacterial outer membrane channels is required to pinpoint the ancestral OEP `portrait gallery'
Beyond aggression: Androgen-receptor blockade modulates social interaction in wild meerkats
In male vertebrates, androgens are inextricably linked to reproduction, social dominance, and aggression, often at the cost of paternal investment or prosociality. Testosterone is invoked to explain rank-related reproductive differences, but its role within a status class, particularly among subordinates, is underappreciated. Recent evidence, especially for monogamous and cooperatively breeding species, suggests broader androgenic mediation of adult social interaction. We explored the actions of androgens in subordinate, male members of a cooperatively breeding species, the meerkat (Suricata suricatta). Although male meerkats show no rank-related testosterone differences, subordinate helpers rarely reproduce. We blocked androgen receptors, in the field, by treating subordinate males with the antiandrogen, flutamide. We monitored androgen concentrations (via baseline serum and time-sequential fecal sampling) and recorded behavior within their groups (via focal observation). Relative to controls, flutamide-treated animals initiated less and received more high-intensity aggression (biting, threatening, feeding competition), engaged in more prosocial behavior (social sniffing, grooming, huddling), and less frequently initiated play or assumed a ‘dominant’ role during play, revealing significant androgenic effects across a broad range of social behavior. By contrast, guarding or vigilance and measures of olfactory and vocal communication in subordinate males appeared unaffected by flutamide treatment. Thus, androgens in male meerkat helpers are aligned with the traditional trade-off between promoting reproductive and aggressive behavior at a cost to affiliation. Our findings, based on rare endocrine manipulation in wild mammals, show a more pervasive role for androgens in adult social behavior than is often recognized, with possible relevance for understanding tradeoffs in cooperative systems
Exceptional endocrine profiles characterise the meerkat: sex, status, and reproductive patterns.
In vertebrates, reproductive endocrine concentrations are strongly differentiated by sex, with androgen biases typifying males and estrogen biases typifying females. These sex differences can be reduced in female-dominant species; however, even the most masculinised of females have less testosterone (T) than do conspecific males. To test if aggressively dominant, female meerkats (Suricata suricatta) may be hormonally masculinised, we measured serum androstenedione (A4), T and estradiol (E2) in both sexes and social classes, during both 'baseline' and reproductive events. Relative to resident males, dominant females had greater A4, equivalent T and greater E2 concentrations. Males, whose endocrine values did not vary by social status, experienced increased T during reproductive forays, linking T to sexual behaviour, but not social status. Moreover, substantial E2 concentrations in male meerkats may facilitate their role as helpers. In females, dominance status and pregnancy magnified the unusual concentrations of measured sex steroids. Lastly, faecal androgen metabolites replicated the findings derived from serum, highlighting the female bias in total androgens. Female meerkats are thus strongly hormonally masculinised, possibly via A4's bioavailability for conversion to T. These raised androgen concentrations may explain female aggressiveness in this species and give dominant breeders a heritable mechanism for their daughters' competitive edge
Organizational and activational androgens, lemur social play, and the ontogeny of female dominance
The role of androgens in shaping “masculine” traits in males is a core focus in behavioral endocrinology, but relatively little is known about an androgenic role in female aggression and social dominance. In mammalian models of female dominance, including the ring-tailed lemur (Lemur catta), links to androgens in adulthood are variable. We studied the development of ring-tailed lemurs to address the behavioral basis and ontogenetic mechanisms of female dominance. We measured behavior and serum androgen concentrations in 24 lemurs (8 males, 16 females) from infancy to early adulthood, and assessed their ‘prenatal’ androgen milieu using serum samples obtained from their mothers during gestation. Because logistical constraints limited the frequency of infant blood sampling, we accounted for asynchrony between behavioral and postnatal hormone measurements via imputation procedures. Imputation was unnecessary for prenatal hormone measurements. The typical sex difference in androgen concentrations in young lemurs was consistent with adult conspecifics and most other mammals; however, we found no significant sex differences in rough-and-tumble play. Female (but not male) aggression increased beginning at approximately 15 months, coincident with female puberty. In our analyses relating sexually differentiated behavior to androgens, we found no relationship with activational hormones, but several significant relationships with organizational hormones. Notably, associations of prenatal androstenedione and testosterone with behavior were differentiated, both by offspring sex and by type of behavior within offspring sexes. We discuss the importance of considering (1) missing data in behavioral endocrinology research, and (2) organizational androgens other than testosterone in studies of female dominance
Endosperm development in Brachypodium distachyon
Grain development and its evolution in grasses remains poorly understood, despite cereals being our most important source of food. The grain, for which many grass species have been domesticated, is a single-seeded fruit with prominent and persistent endosperm. Brachypodium distachyon, a small wild grass, is being posited as a new model system for the temperate small grain cereals, but little is known about its endosperm development and how this compares with that of the domesticated cereals. A cellular and molecular map of domains within the developing Brachypodium endosperm is constructed. This provides the first detailed description of grain development in Brachypodium for the reference strain, Bd21, that will be useful for future genetic and comparative studies. Development of Brachypodium grains is compared with that of wheat. Notably, the aleurone is not regionally differentiated as in wheat, suggesting that the modified aleurone region may be a feature of only a subset of cereals. Also, the central endosperm and the nucellar epidermis contain unusually prominent cell walls that may act as a storage material. The composition of these cell walls is more closely related to those of barley and oats than to those of wheat. Therefore, although endosperm development is broadly similar to that of temperate small grain cereals, there are significant differences that may reflect its phylogenetic position between the Triticeae and rice
Degradation of Indigo Dye Using Quantum Mechanical Calculations
The semiempirical (PM3) and DFT quantum mechanical methods were used to investigate the theoretical degradation of Indigo dye. The chemical reactivity of the Indigo dye was evaluated by comparing the potential energy stability of the mean bonds. Seven transition states were suggested and studied to estimate the actually starting step of the degradation reaction. The bond length and bond angle calculations indicate that the best active site in the Indigo dye molecule is at C10=C11. The most possible transition states are examined for all suggested paths of Indigo dye degradation predicated on zero-point energy and imaginary frequency. The first starting step of the reaction mechanism is proposed. The change in enthalpy, Gibbs free energy and change in entropy of the overall reaction are equal to -548268.223 kcal/mol, 30831.951 kcal/mol and 48.552 cal/mol.deg, respectively. The activation energy is 46176.405 kcal/mol. The reaction rate is equal to
An intergenerational androgenic mechanism of female intrasexual competition in the cooperatively breeding meerkat.
Female intrasexual competition can be intense in cooperatively breeding species, with some dominant breeders (matriarchs) limiting reproduction in subordinates via aggression, eviction or infanticide. In males, such tendencies bidirectionally link to testosterone, but in females, there has been little systematic investigation of androgen-mediated behaviour within and across generations. In 22 clans of wild meerkats (Suricata suricatta), we show that matriarchs 1) express peak androgen concentrations during late gestation, 2) when displaying peak feeding competition, dominance behaviour, and evictions, and 3) relative to subordinates, produce offspring that are more aggressive in early development. Late-gestation antiandrogen treatment of matriarchs 4) specifically reduces dominance behaviour, is associated with infrequent evictions, decreases social centrality within the clan, 5) increases aggression in cohabiting subordinate dams, and 6) reduces offspring aggression. These effects implicate androgen-mediated aggression in the operation of female sexual selection, and intergenerational transmission of masculinised phenotypes in the evolution of meerkat cooperative breeding
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