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In this study, we report a successful strategy for the generation of palladium nanoparticles on porous P-doped carbon spheres with a high surface area. The synthesized Pd/P-CS was used in the CO2 fixation reaction with various epoxides under solvent-free conditions. The prepared Pd0/P-CS nanocatalyst was affirmed by different analysis, including TEM, FE-SEM, EDS, BET, FT-IR, XRD, and ICP-OES. The aforesaid nanocatalyst with a unique porous structure was an outstanding catalytic performance on different substrates toward produce of cyclic carbonates under solvent-free condition with high yields of final products. The catalytic activity of Pd0/P-Cs could be maintained efficiently after recycling up to five consecutive runs under the optimized reaction conditions. [ABSTRACT FROM AUTHOR]

This study investigated mathematical modeling and optimization of the xylene isomerization reaction in a commercial adiabatic reactor. The proposed model, consisting of a set of algebraic and ordinary differential equations, is based on a heterogeneous one‐dimensional steady‐state formulation. To verify the proposed model, the simulation results have been compared to available data from an industrial reactor. A good agreement has been found between the simulation and plant data. The genetic algorithm (GA) method is applied to optimize the reactor operating conditions considering the para‐xylene (p‐xylene) mole fraction in reactor outlet as the main objective function. According to the simulation results, there is an optimum initial temperature for maximizing the objective function. In the optimization process, the p‐xylene mole fraction was enhanced by 3.0% at an optimized feed temperature of 678.04K. [ABSTRACT FROM AUTHOR]

Nano‐catalyst of cobalt‐vanadate (Co‐V/Al2O3, supported on alumina) application in Fischer–Tropsch process (FT) was explored in a various conversions of synthesis gas. The catalyst characterization was performed using different methods including Brunauer–Emmett–Teller (BET) surface area, X‐ray fluorescence (XRF), X‐ray diffraction (XRD), Temperature programmed reduction (TPR) profile, and Transmission electron microscopy (TEM). Due to the extreme complexity and nonlinearity of catalytic processes, adaptive network based fuzzy interface system (ANFIS) was developed as a predictive tool for evaluation of Co‐V/Al2O3 nano‐catalyst performance in FT process. Input vector included reaction condition such as, pressure, temperature, time, and CO/H2 ratio of different experiments while the outputs were composition of CO, CO2, and CH4. The proposed model was used for optimization of the process, also the optimal operating conditions were acquired using particle swarm optimization (PSO). The performance of the algorithms and the quality of the solutions were measured by introducing the optimal operating conditions to obtained model. Comparative studies and results analysis were then conducted on the optimization results. The model result shows a good consistency with experimental observations. [ABSTRACT FROM AUTHOR]

In this paper, the structure of Al2O3 is modified with magnesium to synthesize MgAl2O4 as an oxygen carrier (OC) support. The surface properties and structural stability of the modified support are improved by the incorporation of magnesium in the structure of the support and additionally by narrowing the pore size distribution (about 2.3 nm). Then, iron oxide is impregnated on both an Al2O3 support and a MgAl2O4 support as the oxygen transfer active site. The XRD results showed the formation of solely Fe2O3 on the MgAl2O4 support, while both Fe2O3 and Fe3O4 are detected in the synthesized Fe2O3-Al2O3 structure. The synthesized samples are investigated in chemical looping cycles, including CO reduction (as one of the most important side reactions of chemical looping reforming), at different temperatures (300-500 °C) and oxidation with steam at 700 °C for hydrogen production. The obtained results showed the inhibition of Fe-Al spinel formation in the structure of the Fe2O3-MgAl2O4 OC. In addition, H2 with a purity higher than 98% is achievable in oxidation of the OC with steam. In addition, the activity and crystalline change of the Fe2O3-MgAl2O4 OC is investigated after 20 reduction-oxidation cycles. [ABSTRACT FROM AUTHOR]

Background: Group B streptococcus colonization in pregnant women usually has no symptoms, but it is one of the major factors of newborn infection in developed countries. In Iran, there is a little information about the prevalence of maternal colonization and newborns infected by group B streptococcus. In order to find the necessary information to create a protocol for prevention and treatment of group B streptococcus infection in newborns, we conducted a study of its prevalence among Iranian pregnant women and its vertical transmission to their newborns. Materials and Methods: This is a cross-sectional descriptive and analytic study performed at Prenatal Care Clinic of the Sarem Hospital from 2009 to 2011. The pregnant women with the gestational age of 35-37 weeks were enrolled in the study. The vaginal culture for group B streptococcus was done for 980 mothers based on our protocol. Among 980 mothers, 48 were shown positive vaginal culture; however, 8 cases among these 48 mothers were positive for both vaginal and urine culture. Babies with mothers showing positive vaginal culture were screened for infection using complete blood count /blood culture (B/C) and C-reactive protein (CRP). Then, a complete sepsis workup was performed for babies with any signs of infection in the first 48 hours after birth, and they received antibiotic therapy if necessary. All collected data were analyzed (SPSS version 15). Results: Among 980 pregnant women with vaginal culture, 48 cases had positive group B streptococcus cultures among which 8 mothers also had positive group B streptococcus urine culture. Our findings revealed that 22 (50%) symptomatic neonates were born from the mothers with positive vaginal culture for group B streptococcus. About 28 of them (63%) had absolute neutrophil count more than normal, and 4 (9.1 %) newborns were omitted from the study. Therefore, 50% of neonates showed clinical feature, whereas para-clinical test was required to detect the infection for the rest of neonates who showed no signs or symptoms. Conclusion: The colonization of group B streptococcus in Iranian women is significant, while 50% of newborns from mother with positive vaginal culture were symptomatic after birth; therefore, screening of newborns for group B streptococcus infection is recommended to become a routine practice in all healthcare centers in Iran. [ABSTRACT FROM AUTHOR]

Microthrombi formation and hemolytic anemia are signs of hemolytic-uremic syndrome (HUS) that result from platelet consumption and red blood cell (RBC) destruction due to vascular damage. HUS manifests as a triad of signs: micro-angiopathic hemolytic anemia, throm-bocytopenia, and uremia. Prenatal asphyxia (PA) also leads to renal insufficiency and vascular damage. There is an overlap between the clinical presentation of PA and neonatal atypical HUS. We have reported the case of a neonate with a primary diagnosis of PA and clinical presentation of acute renal failure (ARF), anemia (Hb = 10 g/dl) and thrombocytopenia (Pit = 80000). His APGAR scores were 1 (1 minute), 3 (5 minutes), and 7 (10 minutes). A peripheral blood smear (PBS) was performed, which contained schistocytes (32%) with helmet and burr cells. The neonate's cord blood gas values were: pH of 7.07, HC03 = 11mmol/L, and C02 = 57mmHg. The first two days of life, he was anuric with elevated BUN and Cr (2.1mg/dL) levels. Complement (C3) was within normal limits at 0.65 g/L (0.89 - 1.87 g/L), however C4 was below the lower limit of normal at 0.14 g/L (0.16 - 0.38 g/L). We ruled out other causes of PA such as maternal illness, placenta abnormalities and infections (TORCH). We hypothesized that atypical neonatal HUS can progress to PA because of the presence of severe anemia and microthrombi formation. [ABSTRACT FROM AUTHOR]