Screening of different interactions in oxo-manganese porphyrin dimers containing axial N-donor ligands: a theoretical study

A theoretical analysis for describing the dimeric assemblies of high-valent manganese(v)-oxo meso-tetraphenylporphyrin (TPP) ([(TPP)Mn^VO]₂²⁺) and meso-tetrakis(pentafluorophenyl)porphyrin (TPFPP) ([(TPFPP)Mn^VO]₂²⁺) in the presence of axial N-donor ligands is presented. Our theoretical results revealed two types interactions in dimers: a sandwich-like interaction between phenyl rings of porphyrin molecules, and a non-bonded T-shape interaction between nitrogen donors attached to Mn centers. The curvature in the geometry of porphyrin in the [(TPP)Mn^VO]₂²⁺/N-donor system is significantly smaller than that of [(TPFPP)Mn^VO]₂²⁺/N-donor system. Moreover, the Mn–N_(ax) distances in [(TPFPP)Mn^VO]₂²⁺/N-donor system are shorter than those of [(TPP)Mn^VO]₂²⁺/N-donor system. Also, the donor–acceptor interaction between the imidazoles and the Mn centers are stronger than those of the other ligands in both porphyrins. These results are supported by atoms in molecules (AIM) and natural bond orbital (NBO) analysis.

A DFT analysis for describing the dimeric assemblies of high-valent manganese(v)-oxo meso-tetraphenylporphyrin ([(TPP)Mn^VO]₂²⁺) and meso-tetrakis(pentafluorophenyl)porphyrin ([(TPFPP)Mn^VO]₂²⁺) in the presence of axial N-donor ligands is presented.     

Caesarean Delivery in South-Western Iran: Trends and Determinants in a Community-Based Survey

Objective

To assess trends in caesarean delivery and its associated factors in south-western Iran.

Subjects and Methods

This cross-sectional study was conducted from January 2007 to January 2010 in Fars province, Iran. All deliveries recorded in public and private hospitals were included. The Mann-Whitney U test, χ² test and multivariate logistic regression models were used for analysis of data. A p value less than 0.05 was considered significant.

Results

The rate of caesarean section for the whole sample of 139,159 increased from 51.6% in 2007 to 53.3% in 2009, which was statistically and clinically significant. The rate of caesarean delivery was significantly higher in primiparous compared to multiparous mothers. The rate increased steadily with the mother''s age. The most prevalent recorded reason for caesarean delivery was maternal request. Logistic regression analysis showed that maternal age, previous abortions, underlying maternal disease, gestational age and number of living children were key contributing factors to the choice of mode of delivery.

Conclusion

This study showed an increasing rate of caesarean delivery which should draw the attention of policymakers to factors associated with this mode of delivery.Key Words: Caesarean delivery, Iran, Trend     

Systemic lupus erythematosus in Iran: a study of 2280 patients over 33 years

Objective: Systemic lupus erythematosus (SLE) as a chronic autoimmune disease has a worldwide distribution. There is a wide variation in the natural history of SLE among different ethnic and geographic groups. The aim of this study was to show the manifestations of SLE in Iranian patients. Methods: The study was on manifestations of SLE according to the database of the Rheumatology Research Center (RRC), Tehran, Iran, on registered patients during the period of 1976 to 2009. Results: A total of 2280 SLE patients (2052 female and 228 male) were studied. The female : male ratio was 9 : 1 and the mean age at presentation was 24.4 ± 10.4 years. Prevalence of manifestations included: musculoskeletal (83.2%), cutaneous (81.1%), renal (65.4%), neuropsychiatric (23.4%), pulmonary (21.5%), cardiac (17.2%), and hematologic (66.4%) symptoms. There was positive antinuclear antibodies in 86.4% and anti‐DNA in 82.3% of patients. Overlap syndrome and positive family history with other autoimmune diseases were detected in 7.6% and 3.4% of patients, respectively. Conclusion: In our patients the prevalence of cutaneous involvement was similar to those of nearby countries (with similar climate). Renal involvement was seen more than some other countries especially more than European countries, while other manifestations (such as hematologic and joint involvement) were similar to European countries (with similar ethnicity). We may conclude that genetic and/or climatic factors may lead to different presentations of lupus.     

The enhanced visible-light-induced photocatalytic activities of bimetallic Mn–Fe MOFs for the highly efficient reductive removal of Cr(vi)

The photocatalytic efficiencies of bimetallic MOFs, namely STA-12-Mn–Fe, for the reductive removal of Cr(vi) were explored. The best effective variable values were obtained and correlation between the response and influential variables was optimized via experimental design methodology. Complete Cr(vi) removal was achieved under natural sunlight and fluorescent 40 W lamp radiation at pH 2, with an initial Cr(vi) concentration of 20 mg L⁻¹, and 10 mg of photocatalyst within 30 min. A pseudo-first-order rate constant of 0.132 min⁻¹ at T = 298 K was obtained for the Cr(vi) reduction reaction. The title catalysts revealed high performance in the visible region based on photoefficiency measurements, while improved activity was observed compared to the corresponding single-metal MOFs under natural sunlight, highlighting the synergistic effect between the two metal ions. Trapping experiment results proved that direct electron transfer is the main pathway during the photocatalytic Cr(vi) reduction process.

The photocatalytic efficiencies of bimetallic MOFs for the reductive removal of Cr(vi) were explored. The catalysts revealed higher performance compared to the corresponding single-metal MOFs, highlighting the synergistic effect between the two metal ions.     

Cu(ii)–vitamin C-complex catalyzed photo-induced homocoupling reaction of aryl boronic acid in base-free and visible light conditions

In this work, the photocatalytic efficiency of Cu(ii)–vitamin C complex immobilized on titanium dioxide nanoparticles was exploited in the photo-assisted homocoupling reaction of aryl boronic acids under heterogeneous conditions. The homocoupling reaction affords the corresponding symmetrical biaryls in 50–97% yields at ambient temperature in the air under visible light irradiation without any need for any additive such as base or oxidant. This method tolerates various substituents on the aryl boronic acids such as halogen, carbonyl, and a nitro group. The light-dependent photocatalytic performance of the title catalyst evaluated by action spectra revealed a maximum apparent quantum efficiency (AQYs) at 410 nm demonstrating the visible-light-driven photocatalytic reaction. The as-prepared nano biophotocatalyst proved to be reusable at least six times without losing its activity. Thus this work exhibits a favorable method from the environmental and economic point of view which enables the industrially important reactions such as coupling reactions, to be carried out efficiently under photocatalytic and practically attainable conditions.

TiO₂–ascorbic acid (AA)–Cu(ii), nanohybrid is active in the selective aerobic oxidative homocoupling of aryl boronic acids under heterogeneous conditions in air and visible light conditions.     

A nanoscopic icosahedral {Mo72Fe30} cluster catalyzes the aerobic synthesis of benzimidazoles

In this study, the catalytic efficiency of amorphous {Mo₇₂Fe₃₀} nanocapsules as a safe Keplerate polyoxometalate in organic synthesis was exploited. The easy-made solid catalyst exhibited high efficiency using a very low dosage (0.02–0.05 mol%) in the catalyzed condensation of various aromatic 1,2-diamines and aldehydes for the aerobic synthesis of benzimidazoles with very small E-factor values (0.11–0.33). The superior catalytic activity of amorphous nanoclusters compared to that of its crystalline counterpart was demonstrated. The high activity and recyclability of heterogeneous catalysts in a green reaction media under oxygen atmosphere, make this environmentally benign organic process appropriate for our applied goals.

Catalytic activity of amorphous {Mo₇₂Fe₃₀} nanoclusters as a safe Keplerate polyoxometalate in aerobic synthesis of benzimidazoles was described.     

Cu(ii) vitamin C tunes photocatalytic activity of TiO2 nanoparticles for visible light-driven aerobic oxidation of benzylic alcohols

The incorporation of Cu(OAc)₂ into ascorbic acid coated TiO₂ nanoparticles easily provided a new heterogeneous visible-light active titania-based photocatalyst (TiO₂-AA-Cu(ii)) which was characterized by different techniques such as FT-IR, XPS, ICP-AES, TGA and TEM. A red-shift of the band-edge and a reduction of the band-gap (2.8 eV vs. 3.08 for TiO₂) were demonstrated by UV-DRS and Tauc plots. The combination of the as-prepared TiO₂-AA-Cu(ii) nanoparticles with TEMPO and molecular oxygen (air) afforded an active catalytic system for the selective oxidation of diverse set of benzylic alcohols under solvent-free conditions. A photoassisted pathway was confirmed for oxidation reactions evidenced by good correlation between apparent quantum yield (AQY) and diffuse reflectance spectra (DRS) of the as-prepared nanohybrid. The spectral data and recycling experiments demonstrated the structural stability of the title copper photocatalyst during oxidation reactions.

The combination of TiO₂-AA-Cu(ii) nanoparticles with TEMPO and molecular oxygen (air) afforded an active catalytic system for the selective oxidation of diverse set of benzylic alcohols under solvent-free condition.     

Alteration of rat hippocampal neurogenesis and neuronal nitric oxide synthase expression upon prenatal exposure to tamoxifen

The present study delineates the effect of tamoxifen on neuronal density and expression of neuronal nitric oxide synthase (nNOS) in hippocampal nerve cells during prenatal and postnatal periods in rats. Pregnant rats were administered with tamoxifen one day prior to labor (E21) and on the childbirth day (E22). Hippocampi of embryos at E22 and newborns at postnatal days of 1, 7, and 21 (P1, P7, and P21) were investigated. Density of the neurons in areas of the developing hippocampus including cornu ammonis (CA1, CA3), dentate gyrus, and subiculum were studied. Our findings show that the number of pyramidal neurons was significantly decreased in CA1 and subiculum of tamoxifen-treated rats in E22, P1, and P7. We found that cellular density was lower in early stages of development, however, cellular density and thickness gradually increased during the development particularly in the third week. We found that nNOS expression was decreased in E22, P1, and P7 in animals treated with tamoxifen. The present study shows that tamoxifen affects development and differentiation of postnatal rat hippocampus, CA1 neurons, and nNOS expression.     

Heterogeneous Fenton-like activity of novel metallosalophen magnetic nanocomposites: significant anchoring group effect

Two new pyridine and thiolate anchoring groups were prepared to functionalize γ-Fe₂O₃ nanoparticles for coordinative attachment of simple Fe(iii)- and Mn(iii)salophen complexes. Four new magnetically recoverable composites were characterized by several analytical techniques such as FT-IR, XRD, TGA, EDS compositional analysis and VSM to confirm superparamagnetic properties. TEM images revealed the nanostructure nature of composites with size ranging between 20 and 40 nm. A heterogeneous advanced oxidation process for degradation of some organic dyes as water pollution compounds using an aqueous solution of H₂O₂ were successfully exploited. Several key parameters including the metal center in the salophen complex, initial pH, catalyst dosage, H₂O₂ and dye concentration and temperature were investigated. A significant effect of the anchoring ligand on the degradation efficiency and catalyst stability was documented. The superior catalytic activity and particularly durability of the thiolate-based catalysts were demonstrated in comparison with their Py counterparts. Rate constants of 0.21, 0.17, 0.23 and 0.11 min⁻¹ were obtained for degradation of rhodamine B (RhB), methylene blue (MB), methyl orange (MO), and crystal violet (CV). Finally, a photoluminescence probing technology and radical scavenging measurements were carried out to elucidate the active species involved in the process.

Novel magnetically recoverable Fe(iii)- and Mn(iii)salophen complexes were designed for the effective degradation of hazardous organic dyes using a heterogeneous advanced oxidation process.