A computational study on relationship between quantum chemical parameters and reactivity of the zwitterionic GABA and its agonists: Solvent effect

The agonist activity of the title compounds on GABAC receptor as well as GABA uptake inhibition activity is reported. B3LYP/6-311++G(d,p) calculations have been performed to obtain the quantum chemical descriptors such as global hardness, electrophilicity, the electronic chemical potential of the title compounds. Polarized continuum model has been used to explore the solvent effect on activity of the title compounds in four solvent media, viz., chloroform, ethanol, DMSO, and water. The results obtained from the quantum chemical calculations show that the calculated energy gap and the global hardness, as well as molecular electrostatic potential values, are in good agreement with the experimental data.

Structures of mixed argon-nitrogen clusters

The structures of mixed argon-nitrogen clusters of different compositions are investigated by analyzing core level shifts and relative intensities of surface and bulk sites in the Ar 2p 3/2 regime in soft X-ray photoelectron spectroscopy. These structures are confirmed by core level shift calculations taking induced dipole interactions into account, in which several model structures of the mixed clusters are considered by Monte Carlo simulations. These results suggest that the mixed argon-nitrogen clusters show partial core-shell structures, where an argon core is partially covered by nitrogen molecules

The evolution of commercial institutions and business networks in the Ottoman empire: British merchant families and individual merchants in the Levant trade in the 18th century

This thesis has been written with the purpose of contributing to the existing general literature on the Levant trade while at the same time being informed by recent advances in research on Ottoman business history. Our aim in this thesis was to study the effect of institutional and organizational change that the Levant Company underwent in the 18th century on the evolution of individual business networks. This thesis is based on an examination of British and Ottoman archival documents and Lloyd's Lists and Registers, which have served as our main source of data and information for the purpose of identifying the initiatives undertaken by individual merchants that led to the creation of new business networks after the year 1753. The variables on which this change in the character of trade depended most and the areas in which the impact of such change was experienced most intensely is revealed during the course of our study. This thesis demonstrates the distinctive character of relationships between family merchants on the one hand and individual merchants on the other in different phases of the early, middle and late 18th century. Furthermore, it confirms the effects that the liberalization and easing of access to trade that the Levant Company introduced in the period between 1744 and 1753 as part of a broad institutional as well as legislative transformation. The character and scope of business activity undertaken by Levant merchants changed significantly in consequence. This thesis departs from the current historiography with its network analysis in favour of high-level programming language (Python). It also marks a departure in showing the trade routes of the Levant Company with web-based data visualization and analytical apps (Plotly) through utilising shipping registers for the 18th century

Controlling the microstructure of the porous nickel electrodes in alkaline electrolysers

Ni-based electrodes have been extensively studied for hydrogen evolution reaction (HER) in alkaline electrolysers in an attempt to improve its electrocatalytic activity through alloying it with other metals and/or increasing the surface area. However, the role of microstructure on the electrochemical performance has received little attention. In this study, Ni-based catalysts have been prepared by a powder metallurgy technique including compaction and sintering of a mixture of Ni, starting alloy (consisting of Al3Ni and Al3Ni2) and binder. As-sintered samples were then treated in concentrated alkaline solution for leaching of Al. The microstructural properties are controlled by changing the parameters of the preparation process; i.e. sintering temperature, starting alloy to Ni ratio, leaching temperature and binder properties (concentration and particle size). Increasing the sintering temperature from 625 to 900 °C improved the mechanical strength but also increased the diffusion of Al from Al-rich phases into Ni, resulting in reduced Al-rich phases available after sintering. Since Al can only be leached from Al-rich phases, the specific surface area of micro- and mesopores (with the latter having a size range of 2-14 nm) created during the leaching reduced by almost 90 % from 625 to 900 °C sintering temperature. Although there was a ca. 15 times increase in the specific surface area by increasing the starting alloy concentration from 0 to 60 wt.%, the robustness of catalysts reduced since the compressibility of alloy powder is lower than that of Ni, resulting in increased macroporosity. This suggests that the starting alloy concentration should be in the range of 20-40 wt.% in order to achieve relatively robust and inexpensive porous catalysts without compromising too much the surface area. N2 sorption isotherms showed that leaching at 30 and 50 °C resulted in pores with a slit shape, whilst leaching at 60, 70 and 80 °C lead to ink-bottle pores. This was attributed to increasing leaching rate with higher leaching temperatures in comparison to speed of atomic rearrangement at the surface. Increasing the leaching temperature from 30 to 60 °C improved the specific surface area by almost 4 times, whilst leaching at 60, 70 and 80 °C gave similar surface areas. Greater binder concentrations led to increased macroporosity and surface roughness as well as greater numbers of windows between the adjacent cavities. Consequently, the mechanical strength of porous catalysts reduced due to the decrease in the wall thickness. It was also found that the size of the binder particles influences the robustness of the porous catalysts, with the smaller the binder size the greater the robustness. The comparison of trends in alkaline electrolyser cell voltage and compositional and microstructural properties showed that the surface area has a dominant effect on the electrocatalytic activity for HER in comparison to the composition of Ni-based electrodes. Despite greater Al contents, the cell voltage still decreased with increasing surface areas (with micropores accounting for ca. 80 %). However, it was found that the effective use of micro- and mesopores depends on the pore morphology, with slit-shaped pores being more effectively used during HER in comparison to ink-bottle pores which can be more subject to mass transport limitation. It was shown that H2 bubbles cannot form inside the micro- and mesopores, therefore generated H2 can only leave the pores through diffusion which appears to be favoured by a slit shape in comparison to ink-bottles. It was also found that increasing the amount of large macropores (> 15 µm) is not advantageous to the production of electrodes for alkaline electrolysers as it results in increased electrode thickness and reduced mechanical strength with no measureable improvement in electrochemical performance

Acne Vulgaris

Acne vulgaris is a multifactorial disorder of the pilosebaceous unit. The clinical picture can range from mild comedones to fulminant, scarring cases. Approximately 83–100% of all adolescents experience acne vulgaris at some point of their lives. Although acne often tends to resolve following the adolescent period, many men and women continue to suffer from either active acne or postinflammatory scars into their twenties and thirties. Most patients with acne vulgaris are in the complicated adolescence period and thus carry a distinctive psychosocial burden. They possess a disease stigma on their skin for the external world to criticize every day. For all these reasons, acne is a disease which should be treated promptly and efficiently in all age groups. This chapter will provide a comprehensive and up-to-date review of pathophysiology of acne vulgaris, new molecular mechanisms on the evolving acne lesions, epidemiology of the disease, and latest treatment options. The molecular biology of acne lesions, novel treatment options including cosmetic approaches, their role in acne pathogenesis, pathophysiology, and mechanism of actions of the drugs, safety, and efficacy issues, and various treatment regimens will be discussed along with novel discoveries and areas in which further research is needed

Determination of normal splenic volume in relation to age, gender and body habitus: a stereological study on computed tomography

Background: The aim of this study is to assess and document the dimensions of the normal spleen measured on computed tomography (CT) images with the normal splenic volume measured by Cavalieri principle on CT images and thereby serve as a baseline for comparison in cases of splenomegaly using abdominal CT. To investigate the relationship between these changes and body mass index, gender, abdominal diameters.Materials and methods: We retrospectively reviewed abdominal CT examinations of 212 adults between the ages of 20 and 88 years. There were seven groups of patients. The spleen volume (SV) measurements using abdominal CT images of each patient on the Image Information Systems were performed with Cavalieri principle.Results: The mean SV and splenic length (SL), width (SW), and thickness (ST) for the total study population of 212 patients was 198 ± 88 cm3, 9.96 ± 2.1 cm, 8.87 ±± 1.6 cm and 4.58 ± 0.8 cm, respectively. There was a strong correlation between SV and ST (r = 0.752, p < 0.001), SL (r = 0.735, p < 0.001), SW (r = 0.681,p < 0.001) mean values of total study population. Comparison between mean splenic dimension parameters for males and females showed a statistically significant difference (p = 0.032 for SV, p = 0.04 for ST) but no statistically significant difference with SL and SW. Also there was a positive correlation between SV and body height, sagittal abdominal diameter and transvers abdominal diameter in mean of total groups and female groups, there was no correlation in males.Conclusions: The normal reference ranges for SV and size given in this study canserve as a standard to judge whether splenomegaly is present in patients

Determination of normal splenic volume in relation to age, gender and body habitus: a stereological study on computed tomography

Background: The aim of this study is to assess and document the dimensions of the normal spleen measured on computed tomography (CT) images with the normal splenic volume measured by Cavalieri principle on CT images and thereby serve as a baseline for comparison in cases of splenomegaly using abdominal CT. To investigate the relationship between these changes and body mass index, gender, abdominal diameters. Materials and methods: We retrospectively reviewed abdominal CT examinations of 212 adults between the ages of 20 and 88 years. There were seven groups of patients. The spleen volume (SV) measurements using abdominal CT images of each patient on the Image Information Systems were performed with Cavalieri principle. Results: The mean SV and splenic length (SL), width (SW), and thickness (ST) for the total study population of 212 patients was 198 +/- 88 cm(3), 9.96 +/- 2.1 cm, 8.87 +/- +/- 1.6 cm and 4.58 +/- 0.8 cm, respectively. There was a strong correlation between SV and ST (r = 0.752, p < 0.001), SL (r = 0.735, p < 0.001), SW (r = 0.681, p < 0.001) mean values of total study population. Comparison between mean splenic dimension parameters for males and females showed a statistically significant difference (p = 0.032 for SV, p = 0.04 for ST) but no statistically significant difference with SL and SW. Also there was a positive correlation between SV and body height, sagittal abdominal diameter and transvers abdominal diameter in mean of total groups and female groups, there was no correlation in males. Conclusions: The normal reference ranges for SV and size given in this study can serve as a standard to judge whether splenomegaly is present in patients