Preparation and crystal structures of the isomeric series 4-tolyl-1,2,3,5-dithiadiazolyl, (<i>o</i>-MeC₆H₄CNSSN)₂, (<i>m</i>-MeC₆H₄CNSSN)₂ and (<i>p</i>-MeC₆H₄CNSSN)₂

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A contrastive analysis of the Homeric and Hesiodic augment, with special focus on Hesiod

The 4'-alkoxy-tetrafluorophenyl dithiadiazolyls, ROC6F4CNSSN [R = Me (1), Et (2), nPr (3), nBu(4)] all adopt cis-oid dimers in the solid state. The methoxy derivative 1 adopts a p-stacked AA'AA' motif, whereas propoxy (3) and butoxy (4) derivatives exhibit an AA'BB' stacking. The ethoxy derivative (2) is polymorphic. The a-phase (2a) adopts an AA'BB' motif comparable with 3 and 4, whereas 2ß and 2y are reminiscent of 1 but combine a mixture of both monomers and dimers in the solid state. The structure of 2ß exhibits Z' = 6 with two dimers and two monomers in the asymmetric unit but undergoes a thermally induced phase transition upon cooling below -25 °C to form 2y (Z' = 14) with six dimers and two monomers in the asymmetric unit. The transition is associated with both rotation and translation of the dithiadiazolyl ring. Detailed differential scanning calorimetry and variable temperature powder X-ray diffraction studies coupled with SQUID magnetometry have been used to show that 2a converts irreversibly to 2ß upon heating and that 2ß and 2¿; interconvert through a reversible phase transition with a small thermal hysteresis in its magnetic response

Linear and non-linear dielectric properties of a short-pitch ferroelectric liquid crystal stabilized by a polymer network

Linear and non-linear dielectric measurements were carried out on a ferroelectric liquid crystal stabilized by an anisotropic polymer network. The polymerization process was achieved at room temperature. It was performed from an achiral monomer in the ferroelectric chiral smectic C phase, exhibiting a very short helical pitch and a large polarization. The linear and non-linear dielectric spectroscopy were also completed by textural morphology as well as structural and ferroelectric characterizations. All these measurements were carried out on a pure ferroelectric liquid crystal material and on composite films containing two polymer concentrations. The increase of the polymer network density leads to a decrease of the dielectric strength determined in the linear and non-linear dielectric spectroscopy. The complementarity between the linear and non-linear dielectric measurements and their confrontation with a theoretical model allowed the simultaneous determination of some physical parameters such as macroscopic polarization, rotational viscosity and twist elastic energy. We also discuss the effect of the polymer network density on the obtained physical parameters

Health care utilization among elderly according to body mass index and risk of malnutrition

Background: Malnutrition is prevalent among elderly, and this trend is projected to continue due increased life expectancy and more so, malnutrition has been attributed to morbidity and mortality. Further, investigations reveal that malnutrition is associated with prolonged hospital stay, use of emergency services and long term care services. The association between health care utilization and malnutrition will be explored in this study. Method: The study material was collected from the Tromsø 6 cross-sectional study. The study population is comprised of 4017 elderly women (53.5%) and men (46.5 %) aged ≥65 years. The assessment of malnutrition was effectuated by using the body mass index (BMI) and the Malnutrition Universal Screening Tool (MUST). The BMI was classified in to six categories, while the MUST derived three MUST score categories 0, 1, and 2+. The score 1 and 2+ indicated medium and high risk respectively. While taking into consideration some socio-economic and demographic variables, the exploration of the association between health care utilization (visit to GP or medical specialist last year or surgery the last three years) and nutritional assessment variables was accomplished using cross tabulation, analysis of variance (ANOVA) and logistic regression. Results: The respondents in the higher BMI categories were most likely to visit the GP, but no relationships were found between BMI and use of medical specialist or surgery during the last three years. Inconsistent associations were seen regarding risk of malnutrition and GP consultations, but there were indications that increased risk of malnutrition was associated with higher odds of surgery during the last three years and visit to the medical specialist last year. Discussion: The results suggest that BMI and MUST score is related to selected indicators of health care utilization, but in different directions. The cross-sectional design of the study limits the possibility for conclusions regarding causality. The results may also suggest that elderly subjects at high risk for malnutrition do not get sufficient attention in the primary health care. Search words: elderly, malnutrition, health care utilization, BMI, MUS

A supramolecular approach for modulated photoprotection, lysosomal delivery, and photodynamic activity of a photosensitizer

Prompted by a knowledge of the photoprotective mechanism operating in photosystem supercomplexes and bacterial antenna complexes by pigment binding proteins, we have appealed to a boxlike synthetic receptor (ExBox·4Cl) that binds a photosensitizer, 5,15-diphenylporphyrin (DPP), to provide photoprotection by regulating light energy. The hydrophilic ExBox4+ renders DPP soluble in water and modulates the phototoxicity of DPP by trapping it in its cavity and releasing it when required. While trapping removes access to the DPP triplet state, a pH-dependent release of diprotonated DPP (DPPH22+) restores the triplet deactivation pathway, thereby activating its ability to generate reactive oxygen species. We have employed the ExBox4+-bound DPP complex (ExBox4+⊃DPP) for the safe delivery of DPP into the lysosomes of cancer cells, imaging the cells by utilizing the fluorescence of the released DPPH22+ and regulating photodynamic therapy to kill cancer cells with high efficiency

The new Algerian Digital Seismic Network (ADSN): towards an earthquake early-warning system

Seismic monitoring in Algeria has seen great changes since the Boumerdes earthquake of 21 May 2003. Indeed, the installation of a new digital seismic network has resulted in a significant upgrade of the previous analog telemetry network. <br><br> During the last four years, the number of stations in operation has increased substantially from 25 to 69, and 20 of these are broadband, 2 are very broadband, 47 are short period. 21 are equipped with accelerometers. They are all managed by Antelope software from Kinemetrics (US Cie), and they are all connected in real time and use various modes of transmission (e.g., satellite, internet, mobile phone). The spatial repartition of the stations now cover most of northern Algeria. In addition, 70 GPS stations have recently been added to this seismological network, most of them collocated with the seismological stations. <br><br> Since the installation of the network, the records of local or distant events have improved significantly. The automatic processing of the data in a few minutes allows alert messages to be distributed to Civil Defense and other national authorities to react promptly to any emergency. The current strategy is to improve the data quality, to increase the density of the network by adding about 50 new stations, to reduce the processing time, and to reduce the time needed to send out an alert message. The result should be greatly improved network performance, which will lead to an effective early-warning system

Discrete Open-Shell Tris(bipyridinium radical cationic) Inclusion Complexes in the Solid State

The solid-state properties of organic radicals depend on radical-radical interactions that are influenced by the superstructure of the crystalline phase. Here, we report the synthesis and characterization of a substituted tetracationic cyclophane, cyclobis(paraquat-p-1,4-dimethoxyphenylene), which associates in its bisradical dicationic redox state with the methyl viologen radical cation (MV•+) to give a 1:1 inclusion complex. The (super)structures of the reduced cyclophane and this 1:1 complex in the solid state deviate from the analogous (super)structures observed for the reduced state of cyclobis(paraquat-p-phenylene) and that of its trisradical tricationic complex. Titration experiments reveal that the methoxy substituents on the p-phenylene linkers do not influence binding of the cyclophane toward small neutral guests - such as dimethoxybenzene and tetrathiafulvalene - whereas binding of larger radical cationic guests such as MV•+ by the reduced cyclophane decreases 10-fold. X-ray diffraction analysis reveals that the solid-state superstructure of the 1:1 complex constitutes a discrete entity with weak intermolecular orbital overlap between neighboring complexes. Transient nutation EPR experiments and DFT calculations confirm that the complex has a doublet spin configuration in the ground state as a result of the strong orbital overlap, while the quartet-state spin configuration is higher in energy and inaccessible at ambient temperature. Superconducting quantum interference device (SQUID) measurements reveal that the trisradical tricationic complexes interact antiferromagnetically and form a one-dimensional Heisenberg antiferromagnetic chain along the a-axis of the crystal. These results offer insights into the design and synthesis of organic magnetic materials based on host-guest complexes

Discrete open-shell tris(bipyridinium radical cationic) inclusion complexes in the solid state

The solid-state properties of organic radicals depend on radical–radical interactions that are influenced by the superstructure of the crystalline phase. Here, we report the synthesis and characterization of a substituted tetracationic cyclophane, cyclobis(paraquat-p-1,4-dimethoxyphenylene), which associates in its bisradical dicationic redox state with the methyl viologen radical cation (MV•+) to give a 1:1 inclusion complex. The (super)structures of the reduced cyclophane and this 1:1 complex in the solid state deviate from the analogous (super)structures observed for the reduced state of cyclobis(paraquat-p-phenylene) and that of its trisradical tricationic complex. Titration experiments reveal that the methoxy substituents on the p-phenylene linkers do not influence binding of the cyclophane toward small neutral guests—such as dimethoxybenzene and tetrathiafulvalene—whereas binding of larger radical cationic guests such as MV•+ by the reduced cyclophane decreases 10-fold. X-ray diffraction analysis reveals that the solid-state superstructure of the 1:1 complex constitutes a discrete entity with weak intermolecular orbital overlap between neighboring complexes. Transient nutation EPR experiments and DFT calculations confirm that the complex has a doublet spin configuration in the ground state as a result of the strong orbital overlap, while the quartet-state spin configuration is higher in energy and inaccessible at ambient temperature. Superconducting quantum interference device (SQUID) measurements reveal that the trisradical tricationic complexes interact antiferromagnetically and form a one-dimensional Heisenberg antiferromagnetic chain along the a-axis of the crystal. These results offer insights into the design and synthesis of organic magnetic materials based on host–guest complexes

Electrochemical behavior of magnesium alloys AZ91D, AZCe2, and AZLa1 in chloride and sulfate solutions

The influence of Cl- and SO42- on the electrochemical behavior of AZ91D, AZCe2, and AZLa1 was studied. For all alloys, there was a current plateau in the anodic polarization curves in Na2SO4 solutions. In 0.5% NaCl solution, there was a small current plateau, whereas there was none in the 3.5% and 5% NaCl solutions. This indicated that SO42- is less aggressive than Cl-. The range of the current plateau decreased with increasing SO42- concentration. For all alloys, the high frequency capacitive loop in the Nyquist plots decreased with increasing concentration consistent with the decrease in corrosion resistance with increasing Cl- and SO42- concentration