Theoretical Study of the Electronic Properties of The Curcumin Molecule: Using Density Functional Theory

يهدف البحث الى دراسة الخواص الالكترونية لجزيئة الكركمين والتي توجد في صيغتين أيزوميريتين صيغة الكيتون والأينول وتأثير أستخدام دوال أساس مختلفة من خلال الاعتماد على نظرية دالية الكثافة عند المستوي B3LYP. أنتقال ذرة الهيدروجين من مجموعة الميثيلين المركزية(CH2)  لترتبط بذرة الأوكسجين حتى تشكل أصرة هيدروجينية(O H)  يسبب تغيرات هندسية في شكل الأيزوميرين, حيث شكل الأينول هي تركيب خطي   تقريبا ولكن شكل الكيتون ليس خطي تماما. الدالة 6-311G+(d,p) أعطت نتائج مقنعة للحسابات. كذلك حسابات كل من الطاقة الكلية و طاقة أعلى مدار جزيئي ممتلئ وفجوة الطاقة أكدت أن الكيتون هو الأكثر أستقرارا من الأينول. وأيضا الكيتون لديه قابلية عالية لقبول الألكترونات كما ثبت من خلال قيم كل من طاقة أوطأ مدار جزيئي غير ممتلئ وجهد التأين والألفة الألكترونية و الكهروسالبية.This search aims to study electronic properties of the curcumin moleculewhich exist in two isomers, ketone and enol forms, and the effect of usingdifferent basis setsby relying on density functions theory (DFT) at B3LYP level. The hydrogen atom transfer from the central methylene (CH2) group to an oxygen atom to form strong intra-molecular hydrogen (O H) bond causes geometrical changes in two isomers; where the enol form is structure approximately planar but not completely planar for the ketone form.The results showed that the 6-311G+(d,p) basis set gave sat- isfactory results for calculations. As well as the findings of each of the total energy, the energy of the high occupied molecular orbital and energy gap confirm that the isomer ketone is more stable than isomer enol. Also the ketone has a high electron-accepting, as was proven by the values of the energy of lower unoccupied molecular orbital,ionization potential, electron affinity and electronegativity

Возможность инвестирования в Йемен, которую необходимо реализовать, чтобы компенсировать последствия экономического кризиса

Attracting foreign investments has become one of the most important, critical, and vital concerns for any country seeking to improve its economy and achieve economic growth, as investments must be attracted by providing incentives and improving the business climate, as Yemen is under- going a serious economic transformation as a result of the country's war and instability. In addition, because the Yemeni economy is in desperate need of attracting investors, as well as giving investors some incentives not just to invest, but also to help the state with infrastructural reforms.Привлечение иностранных инвестиций стало одним из самых критически важных и жизненно необходимых вопросов для страны, стремящейся улучшить свою экономику и добиться экономического роста. Так как Йемен проходит серьезную экономическую трансформацию в результате войны и нестабильности в стране, то инвестиции должны быть привлечены путем предоставления стимулов и улучшения делового климата. Экономика Йемена отчаянно нуждается в привлечении инвесторов, поэтому необходимо предоставить им различные стимулы для вложения инвестиций, это окажет помощь государству в проведении инфраструктурных реформ

Tuning thermoelectric properties of graphene/boron nitride heterostructures

Using density functional theory combined with a Green's function scattering approach, we examine the thermoelectric properties of hetero-nanoribbons formed from alternating lengths of graphene and boron nitride. In such structures, the boron nitride acts as a tunnel barrier, which weakly couples states in the graphene, to form mini-bands. In un-doped nanoribbons, the mini bands are symmetrically positioned relative to the Fermi energy and do not enhance thermoelectric performance significantly. In contrast, when the ribbons are doped by electron donating or electron accepting adsorbates, the thermopower S and electronic figure of merit are enhanced and either positive or negative thermopowers can be obtained. In the most favourable case, doping with the electron donor tetrathiafulvalene increases the room-temperature thermopower to -284 μv K(-1) and doping by the electron acceptor tetracyanoethylene increases S to 210 μv K(-1). After including both electron and phonon contributions to the thermal conductance, figures of merit ZT up to of order 0.9 are obtained

Proton Radiative Capture at E_p = 150 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

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

GC-MS vs. GC-MS-MS analysis of pentacyclic terpanes in crude oils from Libya and Serbia - A comparison of two methods

The values of parameters calculated from distribution and abundance of the selected pentacyclic terpanes in crude oils from Libya and Serbia, which were originally derived from gas chromatography-mass spectrometry (GC-MS) were compared with results of quantification based on gas chromatography-mass spectrometry-mass spectrometry (GC-MS-MS). The parameters analyzed are the most often used terpane source and maturity parameters, which were applied to a large sample set of 70 oils, originating from five oil fields. The aim of the paper was to investigate to which extent the measurements of the selected parameters by these two instrumental techniques agree and to determine the influence of differences between parameter values on geochemical interpretation. For that purpose two methods, concordance correlation coefficient and mean-difference plot were used. The obtained results indicate that calculation of C(27)18 alpha(H)-22,29,30-trisnorneohopane/(C(27)18 alpha(H)-22,29,30-trisnorneohopane +C(27)17 alpha(H)-22,29,30-trisnorhopane), C(29)18 alpha(H)-30-norneohopane/C(29)17 alpha(H) 21 beta(H)-30-norhopane and C(29)17 alpha(H)21 beta(H)-30-norhopane/ C(30)17 alpha(H)21 beta(H)-hopane ratios either by GC-MS or GC-MS-MS do not significantly influence interpretation. On the other hand, the determination of C(30)17 beta(H)21 alpha(H)-moretane/C(30)17 alpha(H)21 beta(H)-hopane ratio, gammacerane index and oleanane index by GC-MS vs. GC-MS-MS could notably affect interpretation. These differences can be explained by the co-elution and the peak overlapping in GC-MS but also by better separation, higher precision and better selectivity of the GC-MS-MS. Deviation of the almost all studied parameters from the line of equality was similar for the oils from the same oil field but some differences were observed for the oils from different oil fields. Therefore, when GC-MS-MS results are to be used in organic geochemical interpretations, a regional calibration of GC-MS vs. GC-MS-MS relationship for each petroleum system is highly recommended

The Value of Success: Acquiring Gains, Avoiding Losses, and Simply Being Successful

A large network of spatially contiguous, yet anatomically distinct regions in medial frontal cortex is involved in reward processing. Although it is clear these regions play a role in critical aspects of reward-related learning and decision-making, the individual contributions of each component remains unclear. We explored dissociations in reward processing throughout several key regions in the reward system and aimed to clarify the nature of previously observed outcome-related activity in a portion of anterior medial orbitofrontal cortex (mOFC). Specifically, we tested whether activity in anterior mOFC was related to processing successful actions, such that this region would respond similarly to rewards with and without tangible benefits, or whether this region instead encoded only quantifiable outcome values (e.g., money). Participants performed a task where they encountered monetary gains and losses (and non-gains and non-losses) during fMRI scanning. Critically, in addition to the outcomes with monetary consequences, the task included trials that provided outcomes without tangible benefits (participants were simply told that they were correct or incorrect). We found that anterior mOFC responded to all successful outcomes regardless of whether they carried tangible benefits (monetary gains and non-losses) or not (controls). These results support the hypothesis that anterior mOFC processes rewards in terms of a common currency and is capable of providing reward-based signals for everything we value, whether it be primary or secondary rewards or simply a successful experience without objectively quantifiable benefits