Possible d0 ferromagnetism in MgO doped with nitrogen

We study the possibility of d0 ferromagnetism in the compound MgO doped with nitrogen (N). The Haldane-Anderson impurity model is formulated within the tight-binding approximation for determining the host band-structure and the impurity-host hybridization. Using the quantum Monte Carlo technique, we observe a finite local moment for an N impurity, and long-range ferromagnetic correlations between two N impurities. The ferromagnetic correlations are strongly influenced by the impurity bound state. When the ferromagnetic correlation between a pair of impurities is mapped onto the isotropic Heisenberg model for two spin-1/2 particles, the effective exchange constant J12 is found to increase with increasing temperature. Similar temperature dependence of J12 is also obtained in other diluted magnetic semiconductors, such as zincblende ZnO doped with Mn. The temperature dependence of J12 suggests that the mapping of the full Hamiltonian onto the spin Hamiltonian cannot fully describe the magnetic correlations for the diluted magnetic semiconductors at least in the limit of low impurity spin.Comment: 8 pages, 8 figure

Long-range ferromagnetic correlations between Anderson impurities in a semiconductor host

We study the two-impurity Anderson model for a semiconductor host using the quantum Monte Carlo technique. We find that the impurity spins exhibit ferromagnetic correlations with a range which can be much more enhanced than in a half-filled metallic band. In particular, the range is longest when the Fermi level is located above the top of the valence band and decreases as the impurity bound state becomes occupied. Comparisons with the photoemission and optical absorption experiments suggest that this model captures the basic electronic structure of Ga_{1-x}Mn_xAs, the prototypical dilute magnetic semiconductor (DMS). These numerical results might also be useful for synthesizing DMS or dilute-oxide ferromagnets with higher Curie temperatures.Comment: 4 pages, 4 figure

Methyl lactate synthesis using batch reactive distillation: Operational challenges and strategy for enhanced performance

YesBatch reactive distillation is well known for improved conversion and separation of desired reaction products. However, for a number of reactions, the distillation can separate the reactants depending on their boiling points of them and thus not only reduces the benefit of the reactive distillation but also offers operational challenges for keeping the reactants together. Methyl lactate (ML) synthesis via the esterification of lactic acid (LA) with methanol in a reactive distillation falls into this category and perhaps that is why this process has not been explored in the past. The boiling points of the reactants (LA, methanol) are about 490 K and 337 K while those of the products (ML, water) are 417 K and 373 K respectively. Clearly in a conventional reactive distillation (batch or continuous) methanol will be separated from the LA and will reduce the conversion of LA to ML significantly. Here, first the limitations of the use of conventional batch distillation column (CBD) for the synthesis of ML is investigated in detail and a semi-batch reactive distillation (SBD) configuration is studied in detail where LA is the limiting reactant and methanol is continuously fed in excess in the reboiler allowing the reactants to be together for a longer period. However, this poses an operational challenge that the column has to be carefully controlled to avoid overflow of the reboiler at any time of the operation. In this work, the performance of SBD for the synthesis of ML is evaluated using model based optimization in which operational constraints are embedded. The results clearly demonstrate the viability of the system for the synthesis of ML

Isolation of keratinophilic fungi and aerobic actinomycetes from park soils in Gorgan, North of Iran

Background: Keratinophilic fungi are a group of fungi that colonize in various keratinous substrates and degrade them to the components with low molecular weight. This study was conducted to determine the prevalence of keratinophilic fungi and aerobic Actinomycetes in soil of city parks in Gorgan. Objectives: In this study, we surveyed the city park soils of Gorgan (a northern province of Iran) to determine the identities and diversity of soil aerobic Actinomycetes, keratinophilic and non-keratinophilic fungi. Materials and Methods: A total of 244 soil samples were collected from 22 diferent parks of Gorgan, North of Iran. The samples were collected from the superfcial layer with depth not exceeding than 0-10 cm in sterile polyethylene bags. We used hair bait technique for isolation keratinophilic fungi. The colonies identifed by macroscopic and microscopic characterization after slide culturing. Actinomycetes were isolated by antibiotic dilution methods and detected by using physiological tests such as Lysozyme, Casein, Xanthine, Hypoxanthine, Gelatin, Urea Broth, and modifed acid-fast stain. Results: Totally, 75 isolates of aerobic Actinomycetes were detected that Actinomadura madurae and Nocardia asteroides were the most prevalent strains, with 14.66 and 28% prevalence respectively. Microsporum gypseum was more frequent than other keratinophilic fungi (22.96%) and Aspergillus spp. was the most species of saprophyte fungi (15.92%). Conclusions: This study showed that the collected soil from studied areas was rich of keratinophilic fungi and Actinomycetes, therefore hygiene protocol should be taken to prevent the spread of pathogenic and saprophytes fungi in the environment of susceptible person. © 2013, Ahvaz Jundishapur University of Medical Sciences

Synthesis of methyl decanoate using different types of batch reactive distillation systems

YesMethyl Decanoate (MeDC) is a Fatty Acid Methyl Ester (FAME) and is an important chemical compound with global production of 31 million tons per year. However, synthesis of methyl decanoate (MeDC) via esterification of Decanoic Acid (DeC) with methanol by reactive distillation is operationally challenging due to difficulty of keeping the reactants together in the reaction zone as methanol being the lightest component in the mixture can separate itself easily form the other reactant deteriorating significantly the conversion of DeC using either conventional batch or continuous distillation column. This is probably the main reason for not applying the conventional route for MeDC synthesis. Whether Semi-batch Distillation column (SBD) and the recently developed Integrated Conventional Batch Distillation column (i-CBD) offer the possibility of revisiting such chemical reactions for the synthesis of MeDC is the focus of this paper. The minimum energy consumption (Qtot) as the performance measure is used to evaluate the performances of each of these reactive column configurations for different range of methyl decanoate purity and the amount of product. It is observed that the use of i-CBD column provides much better performance than SBD column in terms of the production time and the maximum energy savings when excess methanol is used in the feed. However, the SBD column is found to perform better than the i-CBD column when both reactants in the feed are in equal amount. Also, the optimization results for a given separation task show that the performance of two-reflux intervals strategy is superior to the single-reflux interval in terms of operating batch time, and energy usage rate in the SBD process at equimolar ratio

Dualisation of the D=7 Heterotic String

The dualisation and the first-order formulation of the D=7 abelian Yang-Mills supergravity which is the low energy effective limit of the D=7 fully Higssed heterotic string is discussed. The non-linear coset formulation of the scalars is enlarged to include the entire bosonic sector by introducing dual fields and by constructing the Lie superalgebra which generates the dualized coset element.Comment: 20 page

Factor V G1691A (Leiden) is a major etiological factor in Egyptian Budd-Chiari syndrome patients

Objective: Budd-Chiari syndrome is a multifactorial disease in which several prothrombotic disorders may predispose patients to the development of thrombosis at this uncommon location (hepatic veins). The aim of this study was to determine the prevalence and characteristics of inherited thrombophilia in Egyptian Budd-Chiari syndrome patients.Materials and Methods: The study included 47 Budd-Chiari syndrome patients (20 children and 27 adults). Genotyping of Factor V G1691A (Leiden), prothrombin G20210A (PT), and methylenetetrahydrofolate reductase C677T were performed using real-time PCR and fluorescence melting curve detection analysis.Results: Factor V Leiden was observed in 29 patients (61.7%). It is the only factor that caused Budd-Chiari syndrome in 18 of the patients and in 5 of the patients with inferior vena cava involvement. Myeloproliferative disease was noted in 12 (25.5%) patients, antiphospholipid syndrome in 5 (10.6%), and Behcet’s disease in 3 (6.4%). Interestingly, 3 of the children with Budd-Chiari syndrome had lipid storage disease.Conclusion: Factor V Leiden was a major etiological factor in Egyptian Budd-Chiari syndrome patients, which may have been related to the high frequency of this mutation in the study region. Factor V Leiden was also a strong thrombophilic factor and the leading cause of inferior vena cava thrombosis in these patients. Lipid storage disease should be included as a risk factor for Budd-Chiari syndrome

Protective Potential of Antioxidant Enzymes as Vaccines for Schistosomiasis in a Non-Human Primate Model

Schistosomiasis remains a major cause of morbidity in the world. The challenge today is not so much in the clinical management of individual patients, but rather in population-based control of transmission in endemic areas. Recent large-scale efforts aimed at limiting schistosomiasis have produced limited success. There is an urgent need for complementary approaches, such as vaccines. We demonstrated previously that anti-oxidant enzymes such as Cu-Zn superoxide dismutase (SOD) and glutathione S peroxidase (GPX), when administered as DNA-based vaccines induced significant levels of protection in inbred mice, greater than the target 40% reduction in worm burden compared to controls set as a minimum by the WHO. These results led us to investigate if immunization of non-human primates with antioxidants would stimulate an immune response that could confer protection, as a prelude for human trials. Issues of vaccine toxicity and safety that were difficult to address in mice were also investigated. All baboons in the study were examined clinically throughout the study and no adverse reactions occurred to the immunization. When our outbred baboons were vaccinated with two different formulations of SOD (SmCT-SOD and SmEC-SOD) or one of GPX (SmGPX), they showed a reduction in worm number to varying degrees, when compared with the control group. More pronounced, vaccinated animals showed decreased bloody diarrhea, days of diarrhea and egg excretion (transmission), as well as reduction of eggs in the liver tissue and in the large intestine (pathology) compared to controls. Specific IgG antibodies were present in sera after immunizations and 10 weeks after challenge infection compared to controls. PBMC, mesenteric and inguinal node cells from vaccinated animals proliferated and produced high levels of cytokines and chemokines in response to crude and recombinant antigens compared with controls. These data demonstrate the potential of antioxidants as vaccine candidates

Integrated Batch Reactive Distillation Column Configurations for Optimal Synthesis of Methyl Lactate

YesAlthough batch reactive distillation process outperforms traditional reactor-distillation processes due to simultaneous reaction and separation of products for many reaction systems, synthesis of Methyl lactate (ML) through esterification of lactic acid (LA) with methanol in such process is very challenging due to difficulty of keeping the reactants together when one of the reactants (in this case methanol) has the lowest boiling point than the reaction products. To overcome this challenge, two novel reactive distillation column configurations are proposed in this work and are investigated in detail. These are: (1) integrated conventional batch distillation column (i-CBD) with recycled methanol and (2) integrated semi-batch and conventional batch distillation columns (i-SBD) with methanol recovery and recycle. Performances of each of these configurations are evaluated in terms of profitability for a defined separation task. In i-SBD column, an additional constraint is included to avoid overflow of the reboiler due to continuous feeding of methanol into the reboiler as the reboiler is initially charged to its maximum capacity. This study clearly indicates that both integrated column configurations outperform the traditional column configurations (batch or semi-batch) in terms of batch time, energy consumption, conversion of LA to ML, and the achievable profit

Dry socket following surgical removal of impacted third molar in an Iranian population: Incidence and risk factors

Introduction: Dry socket (DS) is the most common post‑surgical complication following extraction of impacted molar teeth. Various risk factors have been mentioned for this complication including gender, age, amount of trauma during extraction, difficulty of surgery, inappropriate irrigation, infection, smoking, and oral contraceptive use. The aim of the current study was to evaluate the incidence of DS among surgical removal of impacted third mandibular molar in an Iranian Oral and Maxillofacial Clinic and also identifying the background risk factors.Materials and Methods: A total of 189 patients with a total of 256 surgeries entered this study. Surgeries to remove impacted third mandibular molar teeth between April 2009 and August 2010 were included in this study. A questionnaire containing two sections was designed; in the first section demographic data along with smoking status, oral contraceptive use, menstrual cycle phase, systemic disorders, and use of antibiotics prior to surgery collected; in the second section data regarding difficulty of surgery according to radiograph and surgeon perception after surgery, length of surgery, and number of anesthetic carpules along with data regarding cases returning with DS recorded. Data were reported descriptively and analyzed with Fisher’s exact test and Chi‑square with the confidence interval of 95%.Results: The incidence of DS was 19.14%. Age, gender, systemic disorder, and antibiotics use prior to surgery revealed no significant associations with DS (P > 0.05). However, incidence of DS was significantly relevant to smoking, oral contraceptive use, menstruation cycle, difficulty of the surgery according to pre‑surgery radiograph evaluation and perception of surgeon post‑surgery, length of surgery, and number of carpules used to reach anesthesia (P < 0.05).Conclusion: It is recommended to identify high risk groups when performing extraction surgeries to consider measures in order to reduce postoperative complications.Keywords: Alveolar osteitis, dry socket, incidence, impacted third molar, risk factorsNigerian Journal of Clinical Practice • Oct-Dec 2013 • Vol 16 • Issue