A DFT study of the catalytic pyrolysis of benzaldehyde on ZnO, γ-Al2O3, and CaO models.

The catalytic pyrolysis pathways of carbonyl compounds in coal were systematically studied using density functional theory (DFT), with benzaldehyde (C6H5CHO) employed as a coal-based model compound and ZnO, γ-Al2O3, and CaO as catalysts. The results show that the products of both pyrolysis and catalytic pyrolysis are C6H6 and CO. However, the presence of any of the catalysts changes the reaction pathway and reduces the energy barrier, indicating that these catalysts promote C6H5CHO decomposition. Graphical abstract The presence of catalysts changes the reaction pathway and the energy barrier decreases in the order Ea (no catalyst)> Ea (CaO)> Ea (γ-Al2O3)> Ea (ZnO), indicating that these catalysts promote C6H5CHO decomposition.

Structural properties of polysaccharides from cultivated fruit bodies and mycelium of Cordyceps militaris.

The structural properties of polysaccharides, respectively, obtained from the fermented mycelium and cultivated fruiting bodies of the Cordyceps militaris were investigated and compared in this paper. First, the crude polysaccharides were extracted from the mycelium and the fruiting bodies, respectively. The polysaccharides were successively purified by Sevag and chromatography on Sephadex G-100 column to produce two polysaccharides fractions termed CMPS-II and CBPS-II, respectively. The average molecular weights of CMPS-II and CBPS-II were 1.402×10(3) kDa and 1.273×10(3) kDa, respectively, and they were mainly composed of mannose, glucose and galactose in the mole ratios of 1:28.63:1.41 and 1:12.41:0.74, respectively, for CMPS-II and CBPS-II. Afterward, the structural features of CMPS-II and CBPS-II were investigated by a combination of chemical and instrumental analysis, such as FT-IR, periodate oxidation-Smith degradation, GC-MS, NMR and methylation analysis. The results indicated that structurally, both CMPS-II and CBPS-II were 1,3-branched-galactomannoglucan that had a linear backbone of (1→4)-linked α-D-glucopyranose (Glcp). Congo-red test revealed that CMPS-II and CBPS-II existed as triple-helical chains in 0.05-0.15 M NaOH solution.

[Pretreatment method of near-infrared diffuse reflection spectra used for sugar content prediction of pears].

The content of sugar is an important quality index for pears. However, the traditional sugar measurement methods are time-consuming and destructive. In the present study, the authors measured the sugar content of pears using visible and near infrared diffuse reflection spectroscopy. The pretreatment methods of multiplicative scatter correction (MSC), baseline correction, standard normal variate (SNV) transformation, and moving average algorithms were used on the original absorbance spectrum. Results indicate that the absorbance spectra after pretreatment are better than the original absorbance spectra for prediction. Partial least squares (PLS) regression was also used on the original absorbance spectrum and the absorbance spectrum after moving average and baseline correction. It follows that the forecast accuracy of the absorbance spectra after moving average is higher than that of the original absorbance spectra. The models gave good predictions of the sugar content of pears, with corresponding r values of 0.990 8, and standard errors of predictions of 0.019 0.

Current role of surgery for the treatment of fulminant Clostridium difficile colitis.

OBJECTIVE: This review discusses the current status and progress in studies on fulminant Clostridium difficile colitis (FCDC), including the definition, risk factor, diagnostic role of CT, surgical treatment, postoperative mortality, and new therapeutic strategy. DATA SOURCES: A literature search was conducted mainly in Medline and PubMed published in English between January 2000 and May 2011. The search terms were "ulminant Clostridium difficile colitis" "reatment", "urgery" and "ortality" RESULTS: Recent studies show that the overall mortality rate for FCDC remains high despite early surgical intervention. It has been difficult to identify the real value for surgical intervention in patients with FCDC due to the absence of prospective, randomized studies. Early recognition of patients with FCDC will help a clinician decide the need for treatment in an intensive care setting, multi-disciplinary consultation, and appropriate therapeutic selection. Some studies emphasize the importance of early recognition and emergent surgery at a less severe stage. Monoclonal antibody therapy and intravenous immunoglobulin treatment may be useful for the treatment of FCDC. CONCLUSIONS: Present studies do not provide strong evidence for guiding the surgical treatment of FCDC; hence, creation of collaborative research networks is crucial in order to undertake large prospective multi-center studies for improvement in overall survival.

[Experimental study of acellular dermal matrix biological patch enriched with bone marrow mesenchymal cells for the treatment of external anal sphincter injury].

OBJECTIVE: To investigate the feasibility of bone marrow mesenchymal stem cells(MSC)with the acellular dermal matrix(ADM) biological patch for the treatment of external anal sphincter injury on the animal models. METHODS: Thirty Wistar rats with sphincter injury were randomly divided into three groups. Group A underwent end to end sphincteric repair directly, group B underwent end to end repair and then covered by ADM patch, and group C underwent end to end repair and then covered by ADM which was previously seeded with MSC. After six weeks, the whole ring specimens including anal canal and lower rectum were removed. The hematoxylin and eosin stain and Masson trichrome stain were performed to observe the change of histomorphology. RESULTS: Two weeks later, the majority of rat models presented with moist anus and crissum with loose stools, which indicated that the model was established successfully. Six weeks after repair, in group A and B, the suffusion of fibrous connective tissue and the infiltration of inflammatory cells were observed at the repair site of sphincter. And lots of collagen fiber which was stained into blue deposited dispersedly at the site of repair with no obvious proliferation of capillaries. However, in group C, the blue collagenous fiber which deposited at the sphincter injury site was less than that in groups A and B. Muscle fibers were observed to be stained into red distributed dispersedly at the repair site of sphincter in group C. CONCLUSIONS: Transplantation of ADM biological patch rich in bone MSC can partly improve the regeneration of rat injured anal sphincter and lessen the formation of cicatrix.

[Use of antiperistaltic cecoproctostomy in colorectal reconstruction].

OBJECTIVE: To explore the feasibility and functional outcome of antiperistaltic cecoproctostomy in colorectal reconstruction. METHODS: Fifty-six patients who underwent antiperistaltic cecoproctostomy were retrospectively studied. Indications for antiperistaltic cecoproctostomy included slow transit constipation(n=44), synchronous colon cancer or colonic polyps(n=5), acute obstructing left colon carcinoma(n=4), and adult megacolon(n=3). RESULTS: Short-term postoperative complications included wound infections(n=5), 3 lymphatic leakages(n=3), and inflammatory small bowel obstruction(n=1). One month after antiperistaltic cecoproctostomy, the median frequency of daily bowel movement was 4.0(range, 2-6). After a median follow-up of 4 years(range, 1 month to 7 years), the median daily bowel frequency was 2.5(range, 0.5-4.0). Five patients suffered from long-term postoperative complications including small bowel obstruction(n=3), incision hernia(n=1), and mild cecal dilatation(n=1). The mean Wexner incontinence score was 4.2±1.1. CONCLUSION: Antiperistaltic cecoproctostomy is safe and effective for colorectal reconstruction.

[A finite element investigation of bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation].

OBJECTIVES: To investigate the mechanical properties of bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation with finite element method. METHODS: There was a volunteer with age of 28 years old, body height 172 cm, body weight of 60 kg and without cervical deformity by X rays. The ligamentous, nonlinear, three-dimensional finite element models of normal upper cervical spine (C0-3) was developed and validated. The destabilized model with bilateral atlantoaxial trans-articular screws and atlas laminar hooks was evaluated for quasistatic loading. RESULTS: The finite element model of upper cervical spine consists of 229,047 nodes and 152,475 elements, and correlated well with experimental data for all load cases and could be used for experiment. The finite model with bilateral atlantoaxial trans-articular screws and atlas-laminar hooks predicted that the maximum Von Mises Stress was in the region in which screws penetrated the atlantoaxial articular facet. The novel instrumentation resulted in sufficient stability. CONCLUSION: The bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation is useful and effective for atlantoaxial arthrodesis.