Computational Insight into Conformational Rearrangement and Intramolecular-H Bond Analysis of Some Calix[4]Arenes Including Acryloyl Moiety

T he conformational analyses of Calix[4]arenes reveals four different stable structures conformations ; Cone, Partial Cone, 1,2-Alternate and 1,3-Alternate after employing a density functional theory DFT computational analysis. Intramolecular Hydrogen Bonds IHBs existing Calixarene core cause Cone conformation, supporting to be the best stable state in 1, 2 and 3 compounds. In addition, one needs Natural Bond Orbital NBO analyses of current compounds in order to understand nature of these IHBs. Specifically, it has been shown using NBO that the LP *→σ interactions for O˙˙˙O¯H IHBs and the delocalization LP → π* for O¯C=O are the major contributions to energy stabilization. Of all conformers of compound 4, Partial Cone has the lowest energy, which can be attributed to devoid of intramolecular hydrogen bond due to the absence of free phenolic group

Physical properties of heteroatom doped graphene monolayers in relation to supercapacitive performance

885-891Electrodes fabricated using graphene are quite promising for electric double layer capacitors. However graphene has the limitations of low ‘Quantum Capacitance (QC)’ near fermi level due to the presence of Dirac point that can be modified by doping graphenewith suitable dopant. The density functional theory DFT calculations are performed for doped graphene using Boron, Sulphur and phosphorus as dopants to improve the quantum capacitance of electrodes fabricated using graphene. The calculations are performed at temperatures of 233, 300 and 353 °K. From present calculations no significant temperature dependence of quantum capacitance is observed, however a marked increase in QC of value above 58μFcm-2 is seen. Forphosphorus and Sulphur doped graphene a significant energy gap shift of ~ 1.5 eV from the Fermi level is observed that significantly increases the QC at Fermi level to a high value of ~ 35 μFcm-2. With boron dopant as well, a shift of energy gap ~ 1.25eV from the Fermi level is observed. The shift in Dirac point increases quantum capacitance at Fermi level that in turn can increase the energy density of supercapacitor remarkably. The effect of increasing doping concentration on quantum capacitance is also investigated. These results suggest that doping of graphene may result in significant increase in QC near Fermi level, if the dopants are selected carefully depending upon the use of graphene as a positive or negative electrode. The results of these calculations reveal that the problem of low QC of graphene in the range of interest can be addressed by modifying itssurface and structure chemistry which may increase energy density in supercapacitors

Physical properties of heteroatom doped graphene monolayers in relation to supercapacitive performance

Electrodes fabricated using graphene are quite promising for electric double layer capacitors. However graphene has the limitations of low ‘Quantum Capacitance (QC)’ near fermi level due to the presence of Dirac point that can be modified by doping graphenewith suitable dopant. The density functional theory DFT calculations are performed for doped graphene using Boron, Sulphur and phosphorus as dopants to improve the quantum capacitance of electrodes fabricated using graphene. The calculations are performed at temperatures of 233, 300 and 353 °K. From present calculations no significant temperature dependence of quantum capacitance is observed, however a marked increase in QC of value above 58μFcm-2 is seen. Forphosphorus and Sulphur doped graphene a significant energy gap shift of ~ 1.5 eV from the Fermi level is observed that significantly increases the QC at Fermi level to a high value of ~ 35 μFcm-2. With boron dopant as well, a shift of energy gap ~ 1.25eV from the Fermi level is observed. The shift in Dirac point increases quantum capacitance at Fermi level that in turn can increase the energy density of supercapacitor remarkably. The effect of increasing doping concentration on quantum capacitance is also investigated. These results suggest that doping of graphene may result in significant increase in QC near Fermi level, if the dopants are selected carefully depending upon the use of graphene as a positive or negative electrode. The results of these calculations reveal that the problem of low QC of graphene in the range of interest can be addressed by modifying itssurface and structure chemistry which may increase energy density in supercapacitors

X-ray crystallographic and theoretical study of 4-cyclohexyl-5-(2-furyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione

In order to investiaate the molecular geometry, structural analysis of the title compound (4a) was carried out by single crystal X-ray diffraction. Tautomeric properties and conformations were investigated by semi-empirical (AM1) and ab initio quantum mechanical (RHF/6-31G) calculations. The compound prefers thione tautomer in the solid state. On the other hand, semiempirical calculations show that in the gas phase the thiol tautomer is energetically favored in most cases. (C) 2006 Elsevier B.V. All rights reserved

Synthesis, molecular docking, in silico ADME, and EGFR kinase inhibitor activity studies of some new benzimidazole derivatives bearing thiosemicarbazide, triazole, and thiadiazole

Epidermal growth factor receptor (EGFR), one of the important targets in the development of the anticancer compound, is a member of the ErbB receptor tyrosine kinase receptor family and is highly expressed in solid tumors. Inhibition of EGFR is important for cancer treatment to inhibit the progression and growth of EGFR-expressing tumor cells. Agents targeting EGFR are successful drugs involved in the treatment of various cancers, particularly colorectal, head, neck, lung, and breast cancers. In this study, the design of some novel benzimidazole compounds that can interact with EGFR kinase enzyme, synthesis and analysis of these compounds, and evaluation of their biological activities in vitro was aimed. To reach the target compounds, by reacting acid hydrazides with alkyl isothiocyanates, thiosemicarbazides were formed, then cyclization of these compounds with concentrated sulfuric acid or sodium hydroxide, thiadiazole, or triazole derivatives were obtained. As a result of the study, a total of 38 new benzimidazole derivatives was obtained, and the structures of these compounds were clarified by elemental analysis, mass, H-1, and C-13 NMR spectroscopy. Also, the structure of compound 4c was proven by X-ray crystallography. Molecular docking studies of the synthesized compounds have also been carried out, some molecules with high docking scores have been selected and EGFR kinase inhibitor properties have been tested. Among the compounds tested, it was determined that the most active compound was 12a, which inhibited 68% EGFR at a concentration of 10 mu M

Adli Otopsilerde Santral Sinir Sistemi Enfeksiyonu Saptanan Olguların Değerlendirilmesi

Amaç Çalışmada amacımız, retrospektif olarak santral sinir sistemi enfeksiyonlarının histopatolojik özelliklerini literatür bilgileri ışığında değerlendirmektir. Gereç- Yöntem 1998-2002 yıllarında Adli Tıp Kurumu Morg İhtisas Dairesinde otopsileri yapılan ve santral sinir sistemi enfeksiyonu saptanan 103 olgu çalışmaya alındı. Olgularımız yaş, cinsiyet, ölüm nedenleri (doğal ve travmaya bağlı ölümler) ve beyinde saptanan enfeksiyonun histopatolojik özellikleri açısmdan değerlendirildi. Bulgular Çalışmaya alman 103 olgunun %50,4’ü doğal, %49,6’sı travmaya bağlı gelişen komplikasyonlar sonucunda ölen olgulardı. Olgularımızın 85’i (%83,3) erkek, 18’i (%16,6) kadındı. Histopatolojik olarak, toplam 73 olguda (%70,87) menenjit saptandı. Bu grupta 60 olgu (%58,25) akut piyojenik (bakteryel) menenjit, 8 olgu (%7,76) akut aseptik (viral) menenjit, 5 olgu (%4,85) granülomatöz menenjit olarak değerlendirildi. Granülomatöz menenjit olgularından birinde (%20) beyin sapı tutulumuntın da eşlik ettiği nokardia enfeksiyonu, dördünde (%80) tüberküloz enfeksiyonu saptandı. 19 olguda (%18,44)ensefalit saptandı. Bu grupta 8 olgu nonspesifik ensefalit (%7,76), 5 olgu (%4,85) kuduza bağlı viral ensefalit, 1 olgu (%0,97) HlV’e bağlı ensefalit, 1 olgu (%0,97) progresif mültifokal lökoensefalopati, 4 olgu (%3,88) Prion hastalığı (Jacob-Creutzfeld) olarak değerlendirildi. Serimizde 3 olguda (%2,91) meningoensefalit , 6 olguda (%5,82) beyin absesi, 2 olguda da (% 1,94) non-spesifik serebrit tespit edildi. Sonuç Santral sinir sisteminde enfeksiyon hastalıklarının patolojisi oldukça karmaşık ve sıklıkla birbirleriyle örtüşen tabloları içermektedir. Sonuç olarak, enfeksiyon hastalıklarının patolojisinde mültidisipliner bir laboratuar araştırma yapılması gerekmektedir. Anahtar kelimeler: Santral sinir sistemi enfeksiyonları, otops

Beyinde Vasküler Malformasyona Bağlı Kanama Nedeni ile Ani Ölen Üç Olgu Sunumu

Santral sinir sisteminde görülen damar anomalileri; beyindeki damarlanma bozuklukları sonucu oluşurlar ve otopsilerde tesadüfen saptanan küçük lezyonlardan, öldürücü kafa içi kanamalara neden olan büyük lezyonlara kadar farklı şekillerde görülebilirler. Çalışmamızda 1998-2003 yılları arasında Adli Tıp Kurumu Morg İhtisas Dairesinde ani ölüm nedeni ile otopsileri yapılan ve ölüm nedeni beyinde vasküler malformasyona bağlı subaraknoidal ve intraserebral kanama olarak değerlendirilen üç olgu ele alındı. Olgularımızın yaşları 16-29 arasında olup, ikisi erkek, biri kadındı. Makroskopik incelemede, beyin ve beyincik kıvamında yumuşama, lgulardan birinde sağ parietal lob yerleşimli, diğer ikisinde de beyincik ve beyin sapı yerleşimli parankim içi, intraventriküler ve subaraknoidal kanama alanları saptandı. Mikroskopik incelemede, beyin parankimi içinde yerleşmiş birbirleri ile ilişkili ve kıvrıntılı sırt sırta vermiş damar yapıları izlenmekteydi. Damarların bir kısmı ince duvarlı ve venöz yapıda olmakla birlikte, çoğu özellikleri seçilemeyen (ambigious) damarsal yapılardan oluşmaktaydı. Damarlar arasında nöral doku seçilebilmekteydi. Makroskopik ve mikroskopik bulgular eşliğinde olguların ikisi arteriovenöz malformasyon bağlı subaraknoidal ve intraserebral kanama olarak değerlendirildi. Olgularda ölümün vasküler malformasyona bağlı patolojik beyin kanaması sonucu meydana gelmiş olduğu saptandı. Farklı klinik seyir gösteren, bir kısmı ise klinik sessiz kalabilen bu olgular adli tıp pratiğinde ani ölüm nedeni olarak karşımıza çıkabilmektedir. Bu olgu sunumunun amacı nedeni açıkça ortaya konamayan ölüm olgularında sistematik otopsinin tıp ve adalet açısından değerini bir kez daha vurgulamaktır. Anahtar kelimeler: Arteriyovenöz malformasyon, ani ölüm, otops