Comparing the reaction profiles of single iron catalytic sites in enzymes and in reticular frameworks for methane-to-methanol oxidation

The design of synthetic inorganic catalysts mimicking the first coordination spheres of enzymatic cofactors often results in lower yields and selectivity than their biological counterparts. In this study, we exploit Kohn-Sham density functional methods to compare the reaction profiles of four single iron-based catalysts for the direct oxidation of methane to methanol: two biomimetic models based on two enzymes (cytochrome P450 and taurine dioxygenase [TauD]) and two synthetic reticular frameworks (iron-BEA zeolite and tri-iron oxo-center-based metal-organic framework). Both the biomimetic and inorganic catalysts show almost zero selectivity toward methanol for methane conversions >1% at ambient temperature. This study highlights that iron's first coordination shell can influence selectivity toward methanol but to a limited extent. In the absence of methanol protection strategies, high selectivity can be reached only by mimicking the reaction microenvironment of enzymes beyond the first coordination shell of iron

Nutritional studies of Chara corallina

Physico-chemical analysis of the pond water supporting growth of Chara corallina and of those grown in different culture media in the laboratory conditions have been carried out. The physico-chemical parameters of the water of Napli forest and P.N. Mehra Botanical Garden show that Chara corallina requires less amount of nutrients and the level of pollution is quite low as is evident from the data and standards. The water is clear enough to allow penetration of visibility to its bottom. Napli forest and P.N. Mehra Botanical Garden lack rich diversity which may be attributed to some chemicals released by Chara corallina. In laboratory culture, it is found that Chara corallina can be grown in all three culture media, viz., Allen and Arnon’s medium , Chu-10 medium and BG-11 medium but growth is seen to be the best in Allen and Arnon’s culture medium in comparison with the other two culture media

Perioperative outcomes and adverse events of robotic colorectal resections for inflammatory bowel disease: a systematic literature review

The purpose of this study was to assess outcome measures and cost-effectiveness of robotic colorectal resections in adult patients with inflammatory bowel disease. The Cochrane Library, PubMed/Medline and Embase databases were reviewed, using the text “robotic(s)” AND (“inflammatory bowel disease” OR “Crohn’s” OR “Ulcerative Colitis”). Two investigators screened abstracts for eligibility. All English language full-text articles were reviewed for specified outcomes. Data were pre - sented in a summarised and aggregate form, since the lack of higher-level evidence studies precluded meta-analysis. Primary outcomes included mortality and postoperative complications. Secondary outcomes included readmission rate, length of stay, conversion rate, procedure time, estimated blood loss and functional outcome. The tertiary outcome was cost-effectiveness. Eight studies (3 case-matched observational studies, 4 case series and 1 case report) met the inclusion criteria. There was no reported mortality. Overall, complications occurred in 81 patients (54%) including 30 (20%) Clavien-Dindo III–IV complica - tions. Mean length of stay was 8.6 days. Eleven cases (7.3%) were converted to open. The mean robotic operating time was 99 min out of a mean total operating time of 298.6 min. Thirty-two patients (24.7%) were readmitted. Functional outcomes were comparable among robotic, laparoscopic and open approaches. Case-matched observational studies comparing robotic to laparoscopic surgery revealed a significantly longer procedure time; however, conversion, complication, length of stay and readmission rates were similar. The case-matched observational study comparing robotic to open surgery also revealed a longer procedure time and a higher readmission rate; postoperative complication rates and length of stay were similar. No studies compared cost-effectiveness between robotic and traditional approaches. Although robotic resections for inflamma - tory bowel disease are technically feasible, outcomes must be interpreted with caution due to low-quality studies

Reconstruction of Network Evolutionary History from Extant Network Topology and Duplication History

Genome-wide protein-protein interaction (PPI) data are readily available thanks to recent breakthroughs in biotechnology. However, PPI networks of extant organisms are only snapshots of the network evolution. How to infer the whole evolution history becomes a challenging problem in computational biology. In this paper, we present a likelihood-based approach to inferring network evolution history from the topology of PPI networks and the duplication relationship among the paralogs. Simulations show that our approach outperforms the existing ones in terms of the accuracy of reconstruction. Moreover, the growth parameters of several real PPI networks estimated by our method are more consistent with the ones predicted in literature.Comment: 15 pages, 5 figures, submitted to ISBRA 201

Induction with Rabbit Antithymocyte Globulin following Orthotopic Liver Transplantation for Hepatitis C

Background: Hepatitis C (HCV) is the most common indication for liver transplantation in the US. Objective: Since steroids are the major stimulus of viral replication, we postulated that steroid-free immunosuppression might be a safer approach. Methods: From January 1995 to October 2002, we used steroid plus calcineurin inhibitor (CNI) immunosuppression after liver transplantation for HCV (steroid group, n=81). From October 2002 to June 2007, rabbit antithymocyte globulin (RATG) induction, followed by CNI and azathioprine (RATG group, n=73) was utilized. Results: There were no differences in 1- and 3-year patient/allograft survival rates. The incidence of acute rejection rate (19% vs. 28%), of biopsy-proven HCV recurrence (70% vs. 75%), and chronic rejection (6% vs. 9%) were comparable. The mean time to develop recurrent HCV was significantly longer in the RATG group (16.2 vs. 9.2 months, p=0.008). The incidence of severe portal fibrosis appears to be lower in RATG group compared to the steroid group; 14% vs. 4% (p=0.07). Conclusions: RATG induction is safe and effective after liver transplantation for HCV, but has no impact on the incidence of HCV recurrence and patient/allograft survival. However, a significant delay in time to HCV recurrence and a trend toward less rejection and portal fibrosis was observed

Impact of Controlling the Site Distribution of Al Atoms on Catalytic Properties in Ferrierite-Type Zeolites

Zeolites with the ferrierite (FER) topology are synthesized using a combination of tetramethylammonium (TMA) cations with differently sized cyclic amines (pyrrolidine (Pyr), hexamethyleneimine (HMI), and 1,4- diazabicyclo[2.2.2]octane (DAB)). Using these organic structure-directing agents (SDAs), low Si/Al ratios and concentrated synthesis mixtures favor the crystallization of FER materials. Increasing the size of the cyclic amine or decreasing the aluminum content leads to the crystallization of other phases or the creation of excessive amounts of connectivity defects. TMA cations play a decisive role in the synthesis of the FER materials, and their presence allows the use of HMI to synthesize FER. Proton MAS NMR is used to quantify the accessibility of pyridine to acid sites in these FER samples, where it is found that the FER + HMI + TMA sample contains only 27% acid sites in the 8-MR channels, whereas FER + Pyr and FER + Pyr + TMA contain 89% and 84%, respectively. The constraint index (CI) test and the carbonylation of dimethyl ether (DME) with carbon monoxide are used as probe reactions to evaluate how changes in the aluminum distribution in these FER samples affect their catalytic behavior. Results show that the use of Pyr as an SDA results in the selective population of acid sites in the 8-MR channels, whereas the use of HMI generates FER zeolites with an increased concentration of acid sites in the 10-MR channels

Comments on the article “Clinical and radiological outcomes of fixed- versus mobile-bearing total knee replacement: a meta-analysis”

Diagnosis and treatment of bone and soft tissue tumour