Flash point prediction of organic compounds using a group contribution and support vector machine

The flash point is one of the most important properties of flammable liquids. This study proposes a support vector regression (SVR) model to predict the flash points of 792 organic compounds from the DIPPR 801 database. The input variables of the model consist of 65 different functional groups, logarithm of molecular weight and their boiling points in this study. Cross-validation and particle swarm optimization were adopted to find three optimal parameters for the SVR model. Since the prediction largely relies on the selection of training data, 100 training data sets were randomly generated and tested. Moreover, all of the organic compounds used in this model were divided into three major classes, which are non-ring, aliphatic ring, and aromatic ring, and a prediction model was built accordingly for each class. The prediction results from the three-class model were much improved than those obtained from the previous works, with the average absolute error being 5.11–7.15 K for the whole data set. The errors in calculation were comparable with the ones from experimental measurements. Therefore, the proposed model can be implemented to determine the initial flash point for any new organic compounds.     

Properties of osteoconductive biomaterials: Calcium phosphate cement with different ratios of platelet-rich plasma as identifiers

This study aims to evaluate further the performance of a platelet-rich plasma (PRP) additive incorporated with calcium phosphate bone cement (CPC) in vitro to prove its efficiency as bone graft substitutes and its compatibility to be incorporated into the CPC with other techniques in clinical restoration in vivo. The growth factor release ability and the osteogenic evaluation of PRP, CPC, and PRP/CPC testing groups with 5, 10, and 15 wt.% PRP were compared in vitro. Four groups were measured using non-decalcified staining methods in vivo, which include the testing group of 10 wt.% PRP/CPC selected from the evaluation in vitro, by using both the autograft with rabbit trabecular and CPC-only as comparison groups and the group without grafting material as the control sample. The results obtained through specimen immersion show that growth factor release and alkaline phosphatase activities after osteoprogenitor cell culture had a significantly better effect on 10 and 15 wt.% PRP/CPC than on the other groups in vitro. Analysis results suggest that PRP was still retained in the CPC matrix even after 32 days of immersion. The results in vivo show that the histology of the autograft bone and the control group without grafting material exhibited fibrous connective and adipose tissues, which obviously filled the created cavity even at nine weeks after the operation. Osteoregeneration was more successful in the PRP-additive group, which accumulated bone remodeling than in the other groups. In conclusion, CPC could be a potential carrier with adequate PRP additives that bear a therapeutic potential for enhanced bone tissue regeneration.     

Organic whey as a source of Lactobacillus strains with selected technological and antimicrobial properties

Twenty‐five strains, isolated from raw, non‐pasteurised, organic whey samples, were identified phenotypically and genotypically. Biochemical tests were performed, and enzyme profiles, antibiotic resistance and antimicrobial properties were investigated. Sixteen strains were identified as genus Lactobacillus. Based on 16S rDNA gene sequence, the strains were identified as Lb. plantarum and Lb. fermentum. All of the strains had β‐galactosidase activity, and some of them reduced nitrate content. All strains utilised carbohydrates. The tested strains were characterised by low or average lipolytic and esterolytic activity. Moreover, the strains showed low proteolytic activity which is advantageous for their use as starter cultures for foods with low protein content. Strains Lb. fermentum S20, SM1, SM3, S2R and Lb. plantarum SM5 produced harmful N‐acetyl‐β‐glucosaminidase; moreover, the strain S20 produced also β‐glucuronidase. None of the strains produced α‐chymotrypsin. In phenotypic studies, most of the test strains were susceptible to gentamicin, ampicillin, tetracycline, chloramphenicol, penicillin and erythromycin. Strains Lb. plantarum S1 and Lb. fermentum S4, S7, S8, S10, SM1 and SM3 did not possess any transfer resistance genes. Antagonistic activity of the culture LAB strains was assessed as high or moderate in relation to the indicator strains, with the greatest zones of inhibition for E.coli and the smallest for L. monocytogenes ATCC 15313. This study reveals that the LAB strains isolated from organic whey have high potential for food application. Some strains of species Lb. fermentum (S4, S7, S8, S10) have been identified as the best candidates.     

Expression of Aspergillus nidulans phy Gene in Nicotiana benthamiana Produces Active Phytase with Broad Specificities

A full-length phytase gene (phy) of Aspergillus nidulans was amplified from the cDNA library by polymerase chain reaction (PCR), and it was introduced into a bacterial expression vector, pET-28a. The recombinant protein (rPhy-E, 56 kDa) was overexpressed in the insoluble fraction of Escherichia coli culture, purified by Ni-NTA resin under denaturing conditions and injected into rats as an immunogen. To express A. nidulans phytase in a plant, the full-length of phy was cloned into a plant expression binary vector, pPZP212. The resultant construct was tested for its transient expression by Agrobacterium-infiltration into Nicotiana benthamiana leaves. Compared with a control, the agro-infiltrated leaf tissues showed the presence of phy mRNA and its high expression level in N. benthamiana. The recombinant phytase (rPhy-P, 62 kDa) was strongly reacted with the polyclonal antibody against the nonglycosylated rPhy-E. The rPhy-P showed glycosylation, two pH optima (pH 4.5 and pH 5.5), an optimum temperature at 45~55 °C, thermostability and broad substrate specificities. After deglycosylation by peptide-N-glycosidase F (PNGase-F), the rPhy-P significantly lost the phytase activity and retained 1/9 of the original activity after 10 min of incubation at 45 °C. Therefore, the deglycosylation caused a significant reduction in enzyme thermostability. In animal experiments, oral administration of the rPhy-P at 1500 U/kg body weight/day for seven days caused a significant reduction of phosphorus excretion by 16% in rat feces. Besides, the rPhy-P did not result in any toxicological changes and clinical signs.     

Microstructure of Reaction Zone Formed During Diffusion Bonding of TiAl with Ni/Al Multilayer

In this article, the characterization of the interfacial structure of diffusion bonding a TiAl alloy is presented. The joining surfaces were modified by Ni/Al reactive multilayer deposition as an alternative approach to conventional diffusion bonding. TiAl substrates were coated with alternated Ni and Al nanolayers. The nanolayers were deposited by dc magnetron sputtering with 14 nm of period (bilayer thickness). Joining experiments were performed at 900 °C for 30 and 60 min with a pressure of 5 MPa. Cross sections of the joints were prepared for characterization of their interfaces by scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), high resolution TEM (HRTEM), energy dispersive x-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD). Several intermetallic compounds form at the interface, assuring the bonding of the TiAl. The interface can be divided into three distinct zones: zone 1 exhibits elongated nanograins, very small equiaxed grains are observed in zone 2, while zone 3 has larger equiaxed grains. EBSD analysis reveals that zone 1 corresponds to the intermetallic Al₂NiTi and AlNiTi, and zones 2 and 3 to NiAl.     

Radiation-induced synthesis of solid alkaline exchange membranes with quaternized 1,4-diazabicyclo[2,2,2] octane pendant groups for fuel cell application

In this study, anion exchange membranes having various quaternary ammonium groups were prepared by using a radiation-induced graft polymerization method and followed by subsequent treatment of films with amines. FT-IR and SEM-EDX techniques were employed to monitor the reaction progress. The cross-sectional distribution of the anionic exchange functional groups through the membranes has also been investigated using SEM-EDX technique. The results reveal that the anion exchange groups were found to be evenly distributed throughout the membranes. It was also observed that the physico-chemical properties of the anion exchange membranes such as water uptake, ionic conductivity, thermal stability, chemical stability, mechanical properties, and dimensional stability are largely influenced by the chemical structure of the quaternary ammonium moiety which is attached to the graft chains. Among the prepared anion exchange membranes, the membrane having mono-quaternized 1,4-diazabicyclo[2,2,2]octane moiety was found to have both enhanced chemical and dimensional stabilities, while the others having quaternized trimethylamine or bis-quaternized 1,4-diazabicyclo[2,2,2]octane have the decreased dimensional and chemical stabilities.     

Biodegradation of phenol by Synechocystis sp. in media including triacontanol hormone

Phenol removal levels of Synechocystis sp. were investigated in BG11 media with 10 mg/L triacontanol (TRIA) and without it to test whether the hormone could increase the removal efficiency by increasing biomass. The assays were performed to determine the effect of light on degradation, in media with 119.0–492.8 mg/L phenol under light and dark conditions. At increasing phenol concentrations, the degradation ranged between 98.5 and 100% regardless of a dark or a light condition. Experiments were carried out under light to determine the optimum pH for effective degradation. Optimum pH was found to be 6.5 at 200 mg/L phenol with or without TRIA. Phenol degradation was investigated in the 120.2–826.9 mg/L range. Although 377.4 mg/L phenol was completely degraded in hormone controls within 120 h, degradation was increased by TRIA, and the process was completed in 96 h. These data suggest that Synechocystis sp. has potential for use in the treatment of wastewaters containing phenol.     

Extraction and characterization of pectin from Yuza (Citrus junos) pomace: A comparison of conventional-chemical and combined physical–enzymatic extractions

Pectin from Yuza (Citrus junos) pomace was extracted by using combined physical and enzymatic (CPE) treatment, and their characteristics were compared with those of chemically-extracted pectin. Their physico-chemical and thermo-mechanical properties were also investigated in a wheat flour–water system. The CPE extraction produced pectin with 55% of galaturonic acid and the extraction yield was 7.3%. Also, the pectin obtained by CPE extraction exhibited a higher degree of esterification (46%) than chemically-extracted pectin (41%), which was confirmed by FT-IR analysis. When the pectin solutions were subjected to steady-shear conditions, both samples had shear-thinning properties while high apparent viscosity was observed in the chemically-extracted pectin. Even though the use of both pectins raised the pasting parameters of wheat flour as well as its gelatinization temperature, less change in the pasting properties was found in the wheat flour–water system containing the pectin prepared by CPE treatment. The Mixolab results demonstrated that during mechanical shearing and thermal treatments, the dough samples containing chemically-extracted pectin exhibited enhanced mixing stability, strong protein network structure, and increased peak viscosity.