Preparation and characterization of electrospun nanofibers based on silk sericin powders

The present contribution reports the fabrication and characterization of silk sericin (SS) nanofibers via electrospinning. The function of solution concentration on morphological appearance and average diameter of the electrospun SS membranes was investigated by scanning electron microscopy. The structure and physical properties were observed by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). All beads were acquired in lower concentration of SS solution, 1.3–8.5 wt% of SS solutions, and beaded fibers were produced from 9.6, 11.7, 14.2, and 16.5 wt% of SS solution. The perfect nanofibers acquiring average diameters of 145 and 184 nm were fabricated from 20.9 to 22.9 wt% of SS solution, respectively. Results from FT-IR showed that in the as-spun fibers, SS was present in a random coil conformation, while after heat treatment, the molecular structure of SS was transformed into a β-sheet containing structure. DSC and TG analysis illustrated that trifluoroacetic acid can be eliminated by heating. The availability of SS nanofibers introduces a new set of possible uses of these amazing fibers at a scale not explored before. New uses include small diameter fibers for cell proliferation purposes, nanocomposite reinforcing fibers for nanotechnology, wound dressing, scaffolds for tissue engineering, and other biomedical applications.     

Thin-Film Thermoelectric Modules for Power Generation Using Focused Solar Light

We demonstrated the fabrication of thin-film thermoelectric generators and evaluated their generation properties using solar light as a thermal source. Thin-film elements of Bi_0.5Sb_1.5Te₃ (p-type) and Bi₂Te_2.7Se_0.3 (n-type), which were patterned using the lift-off technique, were deposited on glass substrates using radiofrequency magnetron sputtering. After annealing at 300°C, the average Seebeck coefficients of p- and n-type films were 150???V/K and ?104???V/K, respectively, at 50°C to 75°C. A cylindrical lens was used to focus solar light to a line shape onto the hot side of the thin-film thermoelectric module with 15 p?Cn junctions. The minimum width of line-shaped solar light was 0.8?mm with solar concentration of 12.5 suns. We studied the properties of thermoelectric modules with different-sized p?Cn junctions on the hot side, and obtained maximum open voltage and power values of 140?mV and 0.7???W, respectively, for a module with 0.5-mm p?Cn junctions. The conversion efficiency was 8.75?×?10^?4%, which was approximately equal to the value estimated by the finite-element method.     

Effects of Heavy Element Substitution on Electronic Structure and Lattice Thermal Conductivity of Fe2VAl Thermoelectric Material

By using first-principles cluster calculations, we identified that Ta or W substitution for V is useful for decreasing the lattice thermal conductivity of the Fe₂VAl Heusler alloy without greatly affecting the electron transport properties. It was clearly confirmed that the Fe₂(V_1?x Ta _x )Al_0.95Si_0.05 (x?=?0, 0.025, 0.05), Fe₂(V_0.9?x Ta _x Ti_0.1)Al (x?=?0, 0.10, 0.20), and Fe₂(V_0.9?2x W _x Ti_0.1+x )Al (x?=?0, 0.05, 0.10) alloys indeed possessed large Seebeck coefficient regardless of the amounts of substituted elements, while their lattice thermal conductivity was effectively reduced. As a result of partial substitution of Ta for V, we succeeded in increasing the magnitude of the dimensionless figure of merit of the Heusler phase up to 0.2, which is five times as large as the Ta-free compound.     

Fermentation of meat with koji and commercial enzymes,and properties of its extract

This study was carried out in order to make the Japanese fermented meat sauce shishibishio. The fermentation mixtures (moromi) were prepared by mixing ground pork with salt at one of three levels (15, 20 or 25%), koji (rice fermented with Aspergillus oryzae) and pepper. Commercial enzymes, ie Alcalase or Pectinase 3S, were added in order to accelerate the proteolysis of the moromi. After 3 months of fermentation, counts of viable bacteria were below 300 cfu g^?1, and no coliforms was detected in any moromi. Shishibishio obtained after 3 months had an acceptable seasoning with high peptide and free amino acid content, and good hygienic quality; in particular, no unpleasant smell and taste was found. The addition of Alcalase or Pectinase 3S appreciably increased yield of shishibishio and protein recovery from moromi by accelerating the liquefaction and the proteolysis, resulting in the improvement of the sensory quality of the products. The highest yields were, respectively, 49.8 to 50.6%, collected from moromi in which we used 15% salt. Shishibishio with Alcalase had a higher peptide content but a lower total free amino acid content than that with Pectinase 3S. However, there was not much difference in the sensory evaluations for two enzyme treatments. Copyright © 2005 Society of Chemical Industry     

Production of silk sericin/silk fibroin blend nanofibers

Silk sericin (SS)/silk fibroin (SF) blend nanofibers have been produced by electrospinning in a binary SS/SF trifluoroacetic acid (TFA) solution system, which was prepared by mixing 20 wt.% SS TFA solution and 10 wt.% SF TFA solution to give different compositions. The diameters of the SS/SF nanofibers ranged from 33 to 837 nm, and they showed a round cross section. The surface of the SS/SF nanofibers was smooth, and the fibers possessed a bead-free structure. The average diameters of the SS/SF (75/25, 50/50, and 25/75) blend nanofibers were much thicker than that of SS and SF nanofibers. The SS/SF (100/0, 75/25, and 50/50) blend nanofibers were easily dissolved in water, while the SS/SF (25/75 and 0/100) blend nanofibers could not be completely dissolved in water. The SS/SF blend nanofibers could not be completely dissolved in methanol. The SS/SF blend nanofibers were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, and differential thermal analysis. FTIR showed that the SS/SF blend nanofibers possessed a random coil conformation and ß-sheet structure.     

Chemical and nutritional characteristics of brown seaweed lipids: A review

Several brown seaweeds show high total lipids (TL) contents, ranging from 10 to 20 wt.% per dry weight. The main lipid class is glycoglycerolipids (GL), which are rich in 18:4n?3, 20:5n?3 and 20:4n?6. Brown seaweed TL also contains fucoxanthin as a key functional compound. Despite the high levels of 18:4n?3, 20:5n?3 and 20:4n?6, brown seaweed lipids are stable to oxidation. Their high oxidative stability is partly related to the presence of these polyunsaturated fatty acids in their GL forms. Brown seaweed lipids show anti-obesity and anti-diabetic effects, which are mainly due to the up-regulatory effect of fucoxanthin on energy expenditure in abdominal white adipose tissue and glucose utilization in muscle.     

Grafting vinyl monomers onto silk (Bombyx mori) using different initiators: Properties of grafted silk

The graft–copolymerization of silk with methacrylamide (MAA), 2‐hydroxyethyl methacrylate (HEMA), and methyl methacrylate (MMA) was studied using three different free‐radical initiators: an inorganic peroxide [ammonium persulfate (APS)] and two azo compounds [2,2′‐azobisisobutyronitrile (AIBN) and 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride (ADC)]. The rate and yield of grafting followed the order: APS > AIBN > ADC. The performance of AIBN was close to that of APS in terms of weight gain attained. The degree of yellowing of grafted silk varied as a function of the initiator–monomer system used. APS induced the highest degree of yellowing, regardless of which monomer was used, whereas silk grafted with the MAA/AIBN system displayed the lowest level of yellowing. Moisture regain of grafted silk changed as a function of the hydrophilic/hydrophobic character of the grafted polymer, regardless of the kind of initiator used. Accordingly, tensile properties showed a tendency to decrease with increasing weight gain of grafted silk, the extent of which was independent of the kind of monomer and initiator used. The different initiators did not induce any appreciable change in the fine structure of silk, as demonstrated by optical measurements. Uneven surface deposition of homopolymer was detected to variable extent with MMA and HEMA grafting, whereas the surface of MAA‐grafted silk was completely free of any foreign deposit, independently of the initiator used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1401–1409, 2001     

Clinical results of combination chemotherapy with cisplatin, vinblastine and bleomycin (pvb) for advanced testicular cancer: evaluation of risk criteria

Between 1982 and 1991, 24 patients with advanced testicular germ cell tumor were treated by combination chemotherapy with cisplatin, vinblastine and bleomycin (PVB). Based on short-term efficacy of the PVB regimen and long-term prognosis in our patients, we evaluated 4 risk criteria proposed by Indiana University, National Cancer Institute (NCI), Memorial Sloan-Kettering Cancer Center (MSKCC) and European Organization for Research and Treatment of Cancer (EORTC). Clinical staging were IIA in 8 patients, IIB in 8, IIIA in 1, IIIB in 5 and IIIC in 2. Metastases included retroperitoneal lymph node in 20 cases (> 5 cm in 10), lung in 6, bone and liver in each 1. Complete response (CR) was obtained in 12 (50%) patients and partial response (PR) in 9 (38%). According to the stage and metastatic site, CR was achieved in 75%, 38% and 38%of the stage IIA, IIB and III tumors, respectively, and in 60% and 50% of retroperitoneal and pulmonary metastases, respectively. However, neither CR nor PR was recognized for live and bone metastases. Prognosis was assessed with a mean followup period of 88.5 months. Although all 12 patients with CR were alive, 4 of the 9 with PR and all patients on whom the drug was ineffective died of cancer. Accuracy in predicting prognosis was 82%, 75%, 74%, and 63% using the MSKCC, Indiana, NCI and EORTC risk criteria, respectively.     

Application of the collocation method to vibration analysis of rectangular mindlin plates

The flexural vibration analysis of rectangular Mindlin plates using the collocation method is described. The results obtained by the present method are compared with published results for plates with uniform thickness and two opposite edges simply supported. The comparison shows that the method yields very good results with a relatively small number of collocation points, and that estimates for the higher modes can be obtained without any difficulties. Furthermore, the method is applied to plates with linearly varying thickness, and new findings are presented for the frequencies of plates.