Black brookite rich in oxygen vacancies as an active photocatalyst for CO2 conversion: experiments and first-principles calculations

Photocatalytic CO2 conversion is a clean technology to deal with CO2 emissions, and titanium oxide (TiO2) polymorphs are the most investigated photocatalysts for such an application. In this study, black TiO2 brookite is produced by a high-pressure torsion (HPT) method and employed as an active photocatalyst for CO2 conversion. Black brookite with a large concentration of lattice defects (vacancies, dislocations and grain boundaries) showed enhanced light absorbance, narrowed optical bandgap and diminished recombination rate of electrons and holes. The photocatalytic activity of the black oxide for CO2 conversion was higher compared to commercial brookite and benchmark P25 catalyst powders. First-principles calculations suggested that the presence of oxygen vacancies in black brookite is effective not only for reducing optical bandgap but also for providing active sites for the adsorption of CO2 on the surface of TiO2

Sleep Quality in Chronic Inflammatory Skin Diseases and The Effect on The Dermatology Life Quality Index.

TEZ11483Tez (Uzmanlık) -- Çukurova Üniversitesi, Adana, 2018.Kaynakça (s. 59-66) var.x, 75 s. : res. (bzs. rnk.), tablo ; 29 cm.Amaç: Kronik inflamatuvar deri hastalıklarındaki kaşıntı gibi semptomlar, kişilerin uyku kalitesini ve bağlantılı olarak yaşam kalitesini düşürmektedir. Bu çalışmada, kronik inflamatuvar deri hastalıklarında uyku kalitesini araştırmak, hastalığın ve hastalardaki kişisel özelliklerin uyku kalitesi ile ilişkilerini ve bu ilişkinin Dermatoloji Yaşam Kalite İndeksi üzerine etkilerini değerlendirmek amaçlanmıştır. Gereç ve Yöntem: Çalışmaya, Ocak 2018-Ağustos 2018 tarihleri arasında, Çukurova Üniversitesi Tıp Fakültesi Deri ve Zührevi Hastalıklar Anabilim Dalında takip edilen 200 hasta dahil edildi. Hastalar sosyodemografik veri formu, Pittsburgh Uyku Kalite İndeksi, Dermatoloji Yaşam Kalite İndeksi ve Kaşıntı Şiddeti Görsel Analog Ölçeği anketlerini doldurdu. Bu ölçeklerden elde edilen sonuçlar, uyku kalitesine olan etkilerine göre karşılaştırıldı. Bulgular: Eksik verili hastalar dışlandıktan sonra kalan 195 hastanın 41’i atopik dermatit, 59’u kronik spontan ürtiker, 45’i liken planus ve 50’si psoriazis idi. Uyku kalitesine göre, bağımsız değişkenler arasında yapılan ikili karşılaştırmalarda istatistiksel olarak anlamlı veya anlamlılığa yakın (p<0,10) sonuç veren değişkenler; evlilik durumu, deri hastalığı, kaşıntı skoru, Dermatoloji Yaşam Kalite İndeksi, alkol kullanımı, akciğer hastalığı ve psikiyatrik hastalık idi. Çoklu lojistik regresyon analizinde, uyku kalite indeksi üzerinde, Dermatoloji Yaşam Kalite İndeksi (p<0,001), alkol kullanımı (p<0,05) ve psikiyatrik hastalık (p<0,01) anlamlı prediktörler olarak kaldı. Yapılan analizin prediktivitesi % 69,2, sensitivitesi % 75,0 ve spesifitesi % 65,2 idi. Sonuç: Kronik inflamatuvar deri hastalarında, Dermatoloji Yaşam Kalite İndeksi skorlarının artması, eşlik eden psikiyatrik hastalık olması ve alkol kullanımı yaşam kalitesini ve uyku kalitesini bozmaktadır.Objective: Symptoms such as pruritus in chronic inflammatory skin diseases reduce the quality of life and sleep quality of individuals. The aim of this study was to investigate sleep quality in chronic inflammatory skin diseases and to evaluate the relationship between sleep quality and personal characteristics of the patients and the disease, and the effects of this relationship on Dermatology Life Quality Index. Materials and Methods: In the study, 200 patients who were followed in the Department of Skin and Venereal Diseases of Çukurova University Medical Faculty between January 2018 and August 2018 were included. Patients completed the sociodemographic data form, Pittsburgh Sleep Quality Index, Dermatology Life Quality Index and Itching Severity Visual Analog Scale. The results obtained from these scales were compared according to their effects on sleep quality. Results: After the exclusion of the missing data, for the remaining 195 patients, 41 had atopic dermatitis, 59 had chronic spontaneous urticaria, 45 had lichen planus and 50 had psoriasis. Variables in terms of statistically significant or close to the significance (p <0.10) after the comparisons between the independent variables according to the sleep quality included: the marital status, skin disease, itching score, Dermatology Life Quality Index, alcohol consumption, lung disease and psychiatric disease. After the multivariate logistic regression analysis, Dermatology Life Quality Index (p<0.001), alcohol consumption (p<0,05) and psychiatric disease (p<0,01) remained significant predictors on sleep quality index. The predictability of the analysis was 69,2 %, the sensitivity was 75,0 % and the specificity was 65,2 %. Conclusion: Increased Dermatology Life Quality Index scores, comorbid psychiatric disorders and alcohol consumption impair the quality of life and sleep quality in chronic inflammatory skin diseases.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi tarafından desteklenmiştir. Proje No: TTU-2018-10649

The use of strain sensors for modal identification of aeroelastic structures

Acceleration measurements are most commonly employed to determine mode shapes by modal identification. There are two simple reasons for this: an acceleration sensor is easy to apply and deflection mode shapes can directly be estimated from acceleration signals by experimental or operational modal analysis techniques. In the past strain gauges have played a minor role in modal identification because they were of single use and more difficult to apply. Another drawback is that strain modes need to be converted into deflection modes. Nevertheless there are applications where strain measurements show better performance than acceleration measurements if rotating structures are considered. Recent progress in strain measurement technology with fiber optical strain sensors offering spatially nearly continuous measurements up to more than 100Hz of sampling rate raise the interest for aeroelastic applications. This study will analyze the use of strain sensors for aeroelastic applications

Effects of calcium silicate cements on neuronal conductivity

Objectives: This study evaluated alterations in neuronal conductivity related to calcium silicate cements (CSCs) by investigating compound action potentials (cAPs) in rat sciatic nerves. Materials and methods: Sciatic nerves were placed in a Tyrode bath and cAPs were recorded before, during, and after the application of test materials for 60-minute control, application, and recovery measurements, respectively. Freshly prepared ProRoot MTA, MTA Angelus, Biodentine, Endosequence RRM-Putty, BioAggregate, and RetroMTA were directly applied onto the nerves. Biopac LabPro version 3.7 was used to record and analyze cAPs. The data were statistically analyzed. Results: None of the CSCs totally blocked cAPs. RetroMTA, Biodentine, and MTA Angelus caused no significant alteration in cAPs (p > 0.05). Significantly lower cAPs were observed in recovery measurements for BioAggregate than in the control condition (p < 0.05). ProRoot MTA significantly but transiently reduced cAPs in the application period compared to the control period (p < 0.05). Endosequence RRM-Putty significantly reduced cAPs. Conclusions: Various CSCs may alter cAPs to some extent, but none of the CSCs irreversibly blocked them. The usage of fast-setting CSCs during apexification or regeneration of immature teeth seems safer than slow-setting CSCs due to their more favorable neuronal effects

Oxygen Activation and Dissociation on Transition Metal Free Perovskite Surfaces

Density functional theory and low energy ion scattering spectroscopy were applied to study the mechanism of oxygen dissociation on the SrO-terminated surfaces of strontium titanate (SrTiO₃) and iron-doped strontium titanate (SrTi_1–<i>x</i>Fe_<i>x</i>O_3−δ). Our study reveals that while O₂ dissociation is not favored on the SrO-terminated perovskite surface, oxygen vacancies can act as active sites and catalyze the O–O bond cleavage. Electron transfer from lattice oxygen atoms to the O₂ molecule, mediated by the subsurface transition metal cations, plays an important role in the resulting formation of surface superoxo species. The O₂ molecule dissociates to produce oxygen ions, which are incorporated into the perovskite lattice, and highly active oxygen radicals on the perovskite surface, which further recombine to O₂ molecules. Our focus on the SrO-terminated surface, rather than the TiO₂ layer, which is presumed to be more catalytically active, was driven by experimental observation using low energy ion scattering spectroscopy, which reveals that the surface of SrTiO₃ after high temperature heat treatment is SrO-terminated, and hence this is the surface that is technologically relevant for devices such as solid oxide fuel cells (SOFCs). Our study demonstrates that although the more active BO₂-perovskite layer is not exposed at the gas–solid interface, the SrO-terminated surfaces also actively participate in oxygen exchange reaction

Fast Diffusivity of PF₆^– Anions in Graphitic Carbon for a Dual-Carbon Rechargeable Battery with Superior Rate Property

The diffusivity of PF₆^– intercalated into graphitic carbon is investigated using the galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS). The chemical diffusion constant <i>D</i> of PF₆^– is estimated by the GITT and EIS to be around 10^–12 cm²/s. The diffusivity of PF₆^– in graphitic carbon is comparable to or slightly higher than that of Li⁺ in oxide cathode materials such as LiFePO₄ or LiCoO₂ for Li ion batteries. The activation energy for PF₆^– diffusion is also estimated using EIS and found to be around 0.366 eV. The diffusion route of PF₆^– in graphitic carbon is probed using density functional theory (DFT), and diffusion is found to be slightly easier along the ⟨100⟩ direction than along the ⟨110⟩ direction. The estimated activation energy for PF₆^– diffusion obtained by DFT calculation was about 0.23 eV, which is lower than that estimated using EIS. However, both the experimentally measured and theoretically calculated low activation barrier values confirm the fast diffusivity of PF₆^– along the ⟨100⟩ family of directions in graphitic carbon, which is an interesting phenomenon in light of its large ionic size. This result also suggests that a superior rate property can reasonably be achieved in dual-carbon battery applications