Theoretical studies on the structural, vibrational, conformational analysis and nonlinear optic property of 4-(methoxycarbonyl)-phenylboronic acid

1504-1512In this paper, the structural, electronic, non-linear optical (NLO) properties and vibrational frequencies of 4-(methoxycarbonyl)-phenylboronic acid have been examined theoretically using ab initio Hartree-Fock (HF) and Density Functional Theory (DFT/B3LYP) methods applying the standard 6-311++G(d,p) basis set. 1H- and 13C NMR chemical shifts are calculated by employing the direct implementation of the gauge including-atomic-orbital (GIAO) method at the B3LYP/6-311++G(d,p) and HF/6-31G(d) levels of the theory. There are two conformers, cis-trans(ct) and trans-cis (tc) for title molecule. The energy difference between ct and tc conformers of studied molecule are of 0.126 kcal/mol with B3LYP/6-311++G(d,p) and 0.138 kcal/mol with HF/6-311++G(d,p), respectively. The conformer ct is more stable than the conformer tc. Also, the energy gap differences between the highest occupied and the lowest unoccupied molecular orbitals, dipole moment, polarizability and first static hyperpolarizability are calculated as a function of both dihedral angle (C3-C4-C7-O3), between methoxycarbonyl group (CH3-O-CO-) and benzene ring, and dihedral angle (C2-C1-B-O1), between boronic acid group (-B(OH)2) and benzene ring. In the change of the energy gap and polarizability depending on dihedral angles, it is shown that the polarizabilities follow inverse relationship the energy gaps

Theoretical Studies on The Structural, Vibrational, Conformational Analysis and Nonlinear Optic (NLO) Property of 4-(Methoxycarbonyl) Phenylboronic Acid

In this paper, the structural, electronic, non-linear optical (NLO) properties and vibrational frequencies of 4-(methoxycarbonyl) phenylboronic acid has been examined theoretically using ab initio Hartree-Fock (HF) and Density Functional Theory (DFT/B3LYP) methods applying the standard 6-311++G(d,p) basis set. 1H- and 13C-chemical shifts were calculated by employing the direct implementation of the gauge including-atomic-orbital (GIAO) method at the B3LYP/6-311++G(d,p) and HF/6-31G(d) levels of the theory. There are two conformers, (cis-trans = ct) and (trans-cis = tc) for title molecule. The energy difference between ct and tc conformers of studied molecule are of 0.126 kcal/mol with B3LYP/6-311++G(d,p) and 0.138 kcal/mol with HF/6-311++G(d,p), respectively. The conformer ct is more stable than the conformer tc. Also, the energy gap (ΔΕg) differences between the highest occupied (HOMO) and lowest unoccupied molecular orbitals(LUMO), dipole moment, polarizability and first static hyperpolarizability were calculated as a function of both dihedral angle (C3-C4-C7-O3), between methoxycarbonyl group (CH3-O-CO-) and benzene ring, and dihedral angle (C2-C1-B-O1), between boronic acid group (-B(OH)2) and benzene ring. In the change of the energy gap and polarizability depending on dihedral angles, it was shown that the polarizabilities were follow inverse relationship the energy gaps

Akut perikardit ile komplike olan özafagus yırtığı

Özofagus perforasyonu yüksek mortalite hızı olan ciddi bir durumdur. Özofagus perforasyonunun gecikmiş tanısı mediastinit ve perikardit gibi yıkıcı komplikasyonlarla sonuçlanabilmektedir. Özofagus perforasyonları nadiren yabancı cisim aspirasyonuna bağlı olmaktadır. Bu yazıda tavuk kemiği yutulmasına bağlı ve ilk bulguları akut nonspesifik perikarditi düşündüren komplike olmuş özofagus perforasyonlu 59 yaşında bir erkek olgu sunuldu.Esophageal perforation is a serious condition with a high mortality rate. Delayed detection of esophageal perforation may result in devastating complications such as mediastinitis and pericarditis. Esophageal perforation is rare- ly due to aspiration of foreign bodies. Here we report the case of a 59-year-old male patient with complicated esophageal perforation due to ingestion of a chicken bone, whose first signs are considered to be acute non-specific pericarditis

Komşuluk Yaklaşımı ile Kablosuz Sensör Ağlarda Izgara Temelli Kümeleme Tasarımı ve Uygulaması

Kablosuz sensör ağlar, medikal, askeri, endüstriyel, tarım ve çevresel uygulamada alanı izlemek için yoğun olarak kullanılmaktadır. Bu ağlarda birçok sensör düğüm bulunmaktadır ve bu düğümler kısıtlı kaynaklar sahiptir. Ayrıca bu sensör düğümler tekrar şarj özelliğinin çok olmaması nedeni ile enerjilerini bittiği durumlarda tekrar kullanılamaz hale gelmektedir. Enerji tüketiminin verimli kullanılması bu ağlardaki en önemli çalışma alanlarından biridir. Kümeleme yaklaşımı düğümlerin dağıtıldığı alanı kümelere ayırır ve her küme için bir küme başı seçer. Küme başı küme içerisinde bulunan sensör düğümlerden algılanan verileri toplar, birleştirir ve baz istasyonuna iletir. Kümeleme enerji tüketimini azaltarak ağın ömrünü uzatır. Bu çalışmada ızgara temelli kümeleme işlemi yapılmış ve en çok komşuluğa sahip düğüm küme başı olarak seçilmiştir. Küme başı enerjisi azaldığında ilgili küme içerisinde en çok ikincil komşuluğa sahip düğüm küme başı seçilmektedir. Önerilen yöntem MATLAB simülasyon ortamında gerçekleştirilmiştir. Çalışmada elde edilen bulgular incelendiğinde önerilen yöntemin, kümeleme yapılmadan oluşturulan ağlara kıyasla %60 daha uzun ömürlü olduğu ve sensör düğümlerde enerji tüketiminin verimli hale getirildiği gözlemlenmiştir

Epicardial adipose tissue thickness is associated with myocardial infarction and impaired coronary perfusion

Objective: Epicardial adipose tissue (EAT) is associated with the presence, severity and extent of atherosclerotic coronary artery disease (CAD) in addition to subclinical atherosclerosis. We investigated if EAT thickness is related to acute myocardial infarction in patients with CAD. We also searched for the association between EAT thickness and objective coronary flow and myocardial perfusion parameters such as Thrombolysis in Myocardial Infarction Frame count (TFC) and myocardial blush grade (MBG). Methods: Two-hundred consecutive patients with stable angina pectoris or acute coronary syndrome who were admitted to Ufuk University Faculty of Medicine, Dr Rıdvan Ege Hospital cardiology department were included in this observational, cross-sectional study. EAT thickness was evaluated by conventional transthoracic echocardiography. Coronary angiography was performed to determine the coronary involvement and perfusion. Results: Mean EAT thicknesses were 5.4±1.9 mm, 6.3±1.8 mm, and 8.5±1.4 mm in the stable angina pectoris (SAP), unstable angina pectoris (USAP) and acute myocardial infarction groups, respectively (p<0.001). With increasing EAT thickness, TFC increases whereas mean MBG values decrease (for EAT thickness 7 mm; mean TFC: 21.6±2.2, 25.3±3.3 and 35.2±7.7; and MBG values: 2.98±0.14, 2.83±0.57 and 1.7±1.16, respectively; both p<0.001). Cut-off EAT value to predict AMI was identified as 7.8 mm (ROC analysis AUC:0.876; p<0.001, 95% CI:0.822- 0.927). Sensitivity and specificity of EAT cut-off value 7.8 mm to predict AMI were 81.8% and 82.5% respectively. Conclusion: Increased EAT is associated with AMI and it may prove beneficial for choosing patients who would need more aggressive approach in terms of risk reduction using echocardiography which is a relatively cheap and readily available tool as a follow-up parameter