Perylene Diimide as a Precise Graphene-like Superoxide Dismutase Mimetic

Here we show that the active portion of a graphitic nanoparticle can be mimicked by a perylene diimide (PDI) to explain the otherwise elusive biological and electrocatalytic activity of the nanoparticle construct. Development of molecular analogues that mimic the antioxidant properties of oxidized graphenes, in this case the poly(ethylene glycolated) hydrophilic carbon clusters (PEG–HCCs), will afford important insights into the highly efficient activity of PEG–HCCs and their graphitic analogues. PEGylated perylene diimides (PEGn–PDI) serve as well-defined molecular analogues of PEG–HCCs and oxidized graphenes in general, and their antioxidant and superoxide dismutase-like (SOD-like) properties were studied. PEGn–PDIs have two reversible reduction peaks, which are more positive than the oxidation peak of superoxide (O2•–). This is similar to the reduction peak of the HCCs. Thus, as with PEG–HCCs, PEGn–PDIs are also strong single-electron oxidants of O2•–. Furthermore, reduced PEGn–PDI, PEGn–PDI•–, in the presence of protons, was shown to reduce O2•– to H2O2 to complete the catalytic cycle in this SOD analogue. The kinetics of the conversion of O2•– to O2 and H2O2 by PEG8–PDI was measured using freeze-trap EPR experiments to provide a turnover number of 133 s–1; the similarity in kinetics further supports that PEG8–PDI is a true SOD mimetic. Finally, PDIs can be used as catalysts in the electrochemical oxygen reduction reaction in water, which proceeds by a two-electron process with the production of H2O2, mimicking graphene oxide nanoparticles that are otherwise difficult to study spectroscopically

A DFT and TDDFT Study of Alkylated Trimethylene-Bridged Bis(p-Phenylenediamines)

The conclusions are: (1) LDA predicts fairly well the structures of {pi}-dimers. This has been reported before. Here we show that even the small difference between conformers can be described by LDA. Electron densities suggest a stronger bond is formed in LDA than B3LYP. (2) Though its good performance is possibly due to error cancelations, LDA may be used as a practical tool for large {pi}-dimer systems. (3) TDDFT once again does a good job for the optical transitions. The near-IR band shows a weak dependence on the functional, but a stronger one on the interplanar distance

Online Access to the Topic of Fluid Flow and Biophysical Properties for Students of Medical Institutes

This article is devoted to the transition of students of medical institutes in the modular system of lectures, practical classes and independent work on "Flow of fluids and biophysical properties." The importance of the viscosity coefficient in medicine, its application in diagnosis and forensic medical examination, the Stokes method of finding the viscosity coefficient, the availability of viscometric methods, and the use of the Gess (VK-4) viscometer in medicine to find the viscosity coefficient. It is also shown that the coefficient of surface tension is obtained by the method of drop break and the role of the surface tension coefficient in medicine. &nbsp

Oxidation Products of Doubly Trimethylene-Bridged Tetrabenzyl <i>p</i>‑Phenylenediamine Paracyclophane

We report synthesis and investigation of doubly trimethylene-bridged tetrabenzyl-<i>p</i>-phenylenediamine <b>1­(Bz)</b> in its singly and doubly charged redox states. The singly oxidized monoradical cation, which is a mixed-valence (MV) system with directly interacting charge-bearing units, shows broad and solvent-sensitive intervalence bands consistent with class II compounds according to the Robin–Day classification. The doubly oxidized diradical dication of <b>1­(Bz)</b> exists in the spin-paired singlet state with thermally accessible triplet state. It has similar conformations as the other dimeric <i>p</i>-phenylenediamines, such as derivatives <b>1­(Me)</b> and <b>1­(Et)</b>, in both the solid-state and solution phases. The successful isolation of the single-crystalline <b>1­(Bz)</b>^<b>2+</b> diradical dications with two different in nature counteranions, relatively highly coordinating SbF₆^– and weakly coordinating carborane [undecamethylcarborane HCB₁₁Me₁₁^– (CB^–)], reveals the distinct effect of the nature of counterions on the structural features of diradical dication. Cyclic voltammetry measurements of <b>1­(Bz)</b> in dichloromethane reveal separation of the first and second oxidation potential by 0.12 V (2.8 kcal/mol), indicating relatively stable mixed-valence state in the dichloromethane, whereas in the acetonitrile both the first and second oxidation potentials overlap into one unresolved redox peak with minimal separation

Oxidation Products of Doubly Trimethylene-Bridged Tetrabenzyl <i>p</i>‑Phenylenediamine Paracyclophane

We report synthesis and investigation of doubly trimethylene-bridged tetrabenzyl-<i>p</i>-phenylenediamine <b>1­(Bz)</b> in its singly and doubly charged redox states. The singly oxidized monoradical cation, which is a mixed-valence (MV) system with directly interacting charge-bearing units, shows broad and solvent-sensitive intervalence bands consistent with class II compounds according to the Robin–Day classification. The doubly oxidized diradical dication of <b>1­(Bz)</b> exists in the spin-paired singlet state with thermally accessible triplet state. It has similar conformations as the other dimeric <i>p</i>-phenylenediamines, such as derivatives <b>1­(Me)</b> and <b>1­(Et)</b>, in both the solid-state and solution phases. The successful isolation of the single-crystalline <b>1­(Bz)</b>^<b>2+</b> diradical dications with two different in nature counteranions, relatively highly coordinating SbF₆^– and weakly coordinating carborane [undecamethylcarborane HCB₁₁Me₁₁^– (CB^–)], reveals the distinct effect of the nature of counterions on the structural features of diradical dication. Cyclic voltammetry measurements of <b>1­(Bz)</b> in dichloromethane reveal separation of the first and second oxidation potential by 0.12 V (2.8 kcal/mol), indicating relatively stable mixed-valence state in the dichloromethane, whereas in the acetonitrile both the first and second oxidation potentials overlap into one unresolved redox peak with minimal separation

Financial and socio-economic viability of irrigated agricultural development in the Roper catchment: A technical report from the CSIRO Roper River Water Resource Assessment for the National Water Grid

Sustainable regional development is a priority for the Australian and Northern Territory governments. Across northern Australia, however, there is a scarcity of scientific information on land and water resources to complement local information held by Indigenous owners and landholders. Sustainable regional development requires knowledge of the scale, nature, location and distribution of the likely environmental, social and economic opportunities and the risks of any proposed development. Especially where resource use is contested, this knowledge informs the consultation and planning that underpins the resource security required to unlock investment. In 2019 the Australian Government commissioned CSIRO to complete the Roper River Water Resource Assessment. In response, CSIRO accessed expertise and collaborations from across Australia to provide data and insight to support consideration of the use of land and water resources for development in the Roper catchment. While the Assessment focuses mainly on the potential for agriculture, the detailed information provided on land and water resources, their potential uses and the impacts of those uses are relevant to a wider range of regional-scale planning considerations by Indigenous owners, landholders, citizens, investors, local government, the Northern Territory and federal governments. Importantly the Assessment will not recommend one development over another, nor assume any particular development pathway. It provides a range of possibilities and the information required to interpret them - including risks that may attend any opportunities - consistent with regional values and aspirations. The purpose of this report is to provide information on the costs, risks and benefits of new irrigated development in the catchment of the Roper River, at farm to scheme and regional scales, and supply chains beyond. The overall conclusion is that large public dams would be marginal, but on-farm water sources, suitably sited, could provide good prospects for viable new farms

Monotrimethylene-Bridged Bis‑<i>p</i>‑phenylenediamine Radical Cations and Dications: Spin States, Conformations, and Dynamics

The properties of <i>p</i>-phenylenediamine- (PD-) based systems substantially depend on the molecular topology. The singly bridged PD analogues HMPD and OMPD in which the PD rings are connected by a flexible linker reveal particular electronic properties in their radical cations and dications. The EPR and UV–vis spectra of HMPD^2+•• were found to be exceptionally temperature-sensitive, following a change from the extended conformation (doublet–doublet state) predominant at room temperature to the π-stacked conformation (singlet state) prevailing at dry-ice temperature. Changing the single bridge from (CH₂)₃ to dimethylated CH₂CMe₂CH₂ in OMPD^2+•• causes considerably less of the π-stacked conformation to be present at low temperature as a result of the steric interactions with the methyl groups of the bridge. In contrast to HMPD^2+•• and OMPD^2+••, in which the positive charges are localized separately in each PD^+• ring, in the extended conformation, exchange of the electron (“hole hopping”) between the two PD units (fast at the time scale of EPR experiments) was observed for HMPD^+• and OMPD^+•. This process slows in a reversible manner with decreasing temperature, thus forming the radical cation with the unpaired electron spin density predominantly on one PD core, at low temperatures. Accordingly, a subtle balance between conformational changes, electron delocalization, and spin states could be established

Remittances, rituals and reconsidering women's norms in mahallas : emigrant labour and its social effects in Ferghana Valley

This paper describes recent economic and social changes in Central Asian neighbourhood communities known as mahallas, using data from a town in the Ferghana Valley. First, the paper examines how the increasing costs of life-cycle rituals are damaging the harmony of mahallas. Since 2007, more and more hosts have begun to outsource the provision of food and services for these rituals, using money acquired mostly through emigrant labour. This in turn lessens mahallas’ mutual aid practices, and reveals emerging economic disparities between neighbours. Secondly, the paper argues that emigration has had transformative effects on the lifestyles of Muslim women in mahallas. With the globalization of their economy, conventional local norms are becoming harder to obey, and some young and middle-aged women are choosing to live outside these norms. Dependence on emigrant labour and the associated remittances has significantly affected the lifestyles and morals of mahalla inhabitants.参考文献の記載方法等の点で、出版社版とは微細な違いあ

Lightweight hexagonal boron nitride foam for CO2 absorption

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPWeak van der Waals forces between inert hexagonal boron nitride (h-BN) nanosheets make it easy for them to slide over each other, resulting in an unstable structure in macroscopic dimensions. Creating interconnections between these inert nanosheets can remarkably enhance their mechanical properties. However, controlled design of such interconnections remains a fundamental problem for many applications of h-BN foams. In this work, a scalable in situ freeze-drying synthesis of low-density, lightweight 3D macroscopic structures made of h-BN nanosheets chemically connected by poly(vinyl alcohol) (PVA) molecules via chemical cross-link is demonstrated. Unlike pristine h-BN foam which disintegrates upon handling after freeze-drying, h-BN/PVA foams exhibit stable mechanical integrity in addition to high porosity and large surface area. Fully atomistic simulations are used to understand the interactions between h-BN nanosheets and PVA molecules. In addition, the h-BN/PVA foam is investigated as a possible CO, absorption and as laser irradiation protection material.11989448952FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2013/08293-72016/12340-9The authors thank the Air Force Office of Scientific Research (Grant FA9550-13-1-0084) for funding this research, and Air Force Office of Scientific Research MURI Grant FA9550-12-1-0035 financial support of this research. C.F.W. thanks Sao Paulo Research Foundation (FAPESP) Grant No. 2016/12340-9 for financial support. C.F.W. and D.S.G. acknowledge the Center for Computational Engineering and Sciences at State University of Campinas (FAPESP/CEPID Grant No. 2013/08293-7). S.O. acknowledges financial support from a LANL Director's Postdoctoral Fellowship