Silk fibroin/hyaluronic acid porous scaffold for dermal wound healing

The use of silk protein as a biomaterial has been studied for decades. In this study, silk fibroin (SF)/hyaluronic acid (HA) blend scaffolds were prepared by freeze-drying technique. The structure and properties of the blend scaffolds were examined and analyzed. The results demonstrated that the secondary structures of the SF/HA scaffolds were mainly amorphous and β-sheet structures. The pore radius and porosity of the scaffolds decreased with a decrease in the freezing temperature decrease and an increase in the HA ratio. The pore radius and porosity were regulated from 32.22 μm to 290.76 μm and from 74.1 % to 91.15 %, respectively. In vitro, the SF/HA scaffolds could support the fibroblast cell adhesion and proliferation and showed good cytocompatibility. In vivo, the SF/HA scaffolds were implanted into the dorsum of Sprague Dawley rats to evaluate their bioactivity for dermal tissue reconstruction. The vascular-like structures appeared more rapidly in SF/HA scaffolds than that in the PVA group, and a new dermal layer was formed, as determined by histological analysis. The SF/HA porous scaffolds have promise as a dermal substitute.     

Preparation and performance as PEM of sulfonated pre-oxidized nanofiber/SPEEK composite membrane

Building proton transfer channel is an important strategy to optimize the proton transfer process of the proton exchange membrane (PEM). In this work, sulfonated pre-oxidized nanofibers were prepared by solution blowing of polyacrylonitrile (PAN) nanofibers followed by pre-oxidization and sulfonating, and the nanofibers were composited with SPEEK to enhance its performance as PEM. The results of the proton conductivity verified that the employment of sulfonated pre-oxidized nanofibers improved the proton conductivity. Meanwhile, the introduction of the sulfonated pre-oxidized nanofibers realized the upgrades of the thermostability and water absorbency of the membrane, and led to the decrease of the swelling property and methyl alcohol’s permeability of the material. It is indicated that the composite membrane is promising materials for PEM fuel cells.     

Ultrasound-mediated preparation and evaluation of a collagen/PVP-PCL micro- and nanofiber scaffold electrospun from chloroform/ethanol mixture

In this study, to improve the cellular biocompatibility of PVP-PCL micro- and nanofiber scaffold, a novel electrospun collagen/PVP-PCL micro- and nanofiber scaffold was sucessfully prepared assisted by ultrasonic irradiation using chloroform/ethanol mixtures as solvent. The micro- and nanofibers of the electrospun PCL-PVP scaffolds still presented compact inter-fiber entanglement and three-dimensional netlike network with some certain range of pore space after introducing collagen. The incorporated collagen phase was dispersed as inclusions within the electrospun fibers, and then could be easily released by immersing the scaffold in Hanks simulated body fluid. Meanwhile, the integral triple helix structure of collagen could be maintained after blending with the PVP-PCL mixture due to the weak intermolecular interactions. Furthermore, the suitable mechanical and degradation properties of the PVP-PCL scaffold were still reserved after introducing collagen, and the introduction of collagen could further promote the thermostability of the PVP-PCL scaffold. Above all, the collagen/PVP-PCL scaffold showed no cytotoxicity, better cell proliferation, and improved viability of primary fibroblasts than the PVP-PCL scaffold. In conclusion, blending collagen with the PVP-PCL mixture in this study has potential for promoting the biocompatibility of PVP-PCL micro- and nanofiber scaffolds for tissue engineering.     

Exploration of AgNW/PU nanoweb as ECG textile electrodes and comparison with Ag/AgCl electrodes

This study aims to measure ECG signals by the AgNW/PU nanoweb electrodes, and, to compare with signals measured by the conventional Ag/AgCl electrodes. Finally, to investigate the usage potential of the AgNW/PU nanoweb as ECG textile electrodes. The ECG textile electrodes were fabricated, using the polyurethane (PU) nanoweb (Pardam, s.r.o., Czech Republic) coated with 1 wt% of silver nanowires (AgNW) dispersed in ethanol (KLK Co., Korea). To measure the ECG signals, eight participants (Male:Female=1:1) were collected, and then, the signals were measured at rest-state and stress-state in anechoic chamber using Lead I method. From the measured ECG signals, heart rate (HR) and R-R intervals were acquired by using MP150 (Biopac system Inc., USA) and Acqknowledge (ver. 4.2, Biopac system Inc., USA), and then, analyzed by using Kubios HRV (ver. 2.0., Biosignal Analysis and Medical Imaging Group, Finland). To examine the morphology of the signals, direct visual evaluation was performed. Also, to statistically compare to the signals, Wilcoxon signed-rank test was conducted by using R statistical language and RStudio (1.0.143 ver., RStudio, Inc., USA). As a result, the ECG waveforms measured by the two different types of electrodes looked similar, especially, QRS-complex, P-wave and T-wave as well as R-peaks properly appeared. Also, there was not a significant difference of HR and RR-intervals measured by the two different types of electrodes. It demonstrated that the new AgNW/PU nanoweb electrodes could perform properly as ECG electrodes.     

In vitro tuberization of potato sprouts as affected by ethrel and gibberellic acid

Summary In vitro tuberization of etiolated potato sprouts was considerably advanced by a dose of 50 ppm ethrel (2-chloro-ethyl-phosphonic acid). The adition of ethrel also increased the number of tubers, produced shorter and thicker stolons and reduced root development. Some of these effects are opposite to those induced by gibberellic acid which is known to retard tuberization and to promote elongation. When both substances were simultaneously supplied to the medium, they showed a clear antagonistic interaction.     

缓/控释肥料类型及质量评价方法

缓/控释肥料具有减少养分淋失、挥发损失,提高肥料利用率等诸多优点,近年来在国内发展尤其迅速,是今后肥料发展的主要方向之一。介绍缓/控释肥料的概念、分类和质量评价方法,并对今后的研究方向进行展望。     

In vitro digestibility and calculated PER as rapid methods for the nutritional evaluation of potato protein

Protein Efficiency Ratios (PER) have been determined for hybrid potato selections by feeding flake diets to rats; more rapid and inexpensive tests are required by breeding programs which select for improved potato protein. Two more recent methods, in vitro digestibility (IVD) and calculated PER utilizing discriminant computed PER (DC-PER) and computed PER (C-PER), were studied for their potential in evaluation of the nutritional quality of potato. Albumin (A) and two subfractions, acid soluble and insoluble (ASA and AIA), were studied, as well as flakes. The average IVD for albumin was 68.9%, for ASA was 67.5% and for AIA was 77.5%. Digested proteins were identified by electrophoresis before and after enzyme treatment. The higher IVD values for AIA were probably due to the presence of protease inhibitors among the ASA proteins. IVD differences among groups of hybrids were found and a reasonable correlation (r=0.71*) of these values with flake PER values was observed. The DC-PER values ranged from 2.64 to 2.79, these values were larger than those observed in feeding trials; additional genotypes need to be studied before this method can be proposed for potato evaluation. The presence of protease inhibitors in the albumin samples is indicated, because the average IVD value of 68 increased to about 84 after the albumins were heated prior to IVD determinations.Scientific Journal Article 12,095 of the Minnesota Agricultural Experiment Station. This research was supported by a USDA/SEA Grant.     

An evaluation of three bacterial inoculants and formic acid as additives for first harvest grass

An experiment was carried out during 1984 to study the effect of treating grass at ensiling with three commercially available inoculant-type additives (H/M Inoculant, Grass Sile and Siron), formic acid (850 g kg⁻¹; Add-F) or no additive on grass preservation, in-silo loss, intake and animal performance. Primary growth grass ensiled from 28–29 May into concrete-walled covered silos was of high dry matter (DM, 234 g kg⁻¹), water-soluble carbohydrate content (WSC. 212 g kg DM⁻¹) and digestibility (MADF, 250 g kg DM⁻¹).
The untreated silage displayed good preservation and with the exception of the Sirontreated silage which showed significantly lower buffering capacity (Be) and volatile fatty acid (VFA) contents than the untreated silage, the application of inoculant-type additives did not improve silage preservation or decrease in-silo DM losses. The formic acid-treated silage displayed significantly lower Be, water-soluble carbohydrate, ash, ammonia nitrogen (g kg total N⁻¹) and lactate contents than the untreated silage.
After a 133 d storage period, silages were offered to finishing beef cattle for an 84-d period. Cattle offered the silages displayed similar and non-significant daily DM intakes, daily liveweight gains, dressing proportions and daily carcass gains. From this experiment it appears unlikely that any of the additives evaluated will improve animal performance relative to a well-preserved untreated silage.     

Amino acid composition and chemical evaluation of protein quality of cereals as affected by insect infestation

A significant decrease in essential amino acids of wheat, maize and sorghum was observed due to grain infestation caused by mixed populations ofTrogoderma granarium Everts andRhizopertha dominica Fabricius (50:50). Non-essential amino acids were also adversely affected. Among the essential amino acids, maximum reduction was found in methionine, isoleucine and lysine in infested wheat, maize and sorghum grains, respectively. Lysine, with lowest chemical score in uninfested and infested grains of three cereals, is the first limiting amino acid. Insect infestation caused significant (p<0.05) reduction in the chemical score of all the essential amino acids, yet did not change the position of first and second limiting amino acids in wheat and sorghum. However, in case of maize, isoleucine became the second limiting amino acid. Infested grains also showed substantial reduction in essential amino acid index, calculated biological value and requirement index.     

Immunomodulatory Effects of Domoic Acid Differ Between In vivo and In vitro Exposure in Mice

The immunotoxic potential of domoic acid (DA), a well-characterized neurotoxin, has not been fully investigated. Phagocytosis and lymphocyte proliferation were evaluated following in vitro and in vivo exposure to assay direct vs indirect effects. Mice were injected intraperitoneally with a single dose of DA (2.5 μg/g b.w.) and sampled after 12, 24, or 48 hr. In a separate experiment, leukocytes and splenocytes were exposed in vitro to 0, 1, 10, or 100 μM DA. In vivo exposure resulted in a significant increase in monocyte phagocytosis (12-hr), a significant decrease in neutrophil phagocytosis (24-hr), a significant decrease in monocyte phagocytosis (48-hr), and a significant reduction in T-cell mitogen-induced lymphocyte proliferation (24-hr). In vitro exposure significantly reduced neutrophil and monocyte phagocytosis at 1 μM. B- and T-cell mitogen-induced lymphocyte proliferation were both significantly increased at 1 and 10 μM, and significantly decreased at 100 μM. Differences between in vitro and in vivo results suggest that DA may exert its immunotoxic effects both directly and indirectly. Modulation of cytosolic calcium suggests that DA exerts its effects through ionotropic glutamate subtype surface receptors at least on monocytes. This study is the first to identify DA as an immunotoxic chemical in a mammalian species.     

Sound absorption properties of spiral vane electrospun PVA/nano particle nanofiber membrane and non-woven composite material

In this research, we fabricated a series of PVA membranes loaded with 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.% ZrC and 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.% TiO₂ using a spiral vane electrospun machine respectively. There were 2 sizes of TiO₂ nano particles: 10 nm and 200 nm. We tested sound absorption properties of needle-punched nonwovens as well as the composite of nano membranes and needle-punched nonwovens by an impedance tube at the frequency range from 500 Hz to 6500 Hz. Besides, we tested morphological characterization of nano membranes by scanning electron microscope (SEM) and crystalline properties by X-ray diffraction (XRD). We investigated the sound absorption properties of composites as well as the effect of ZrC, TiO₂, nano particle sizes and cavity depth on sound absorption properties. Results showed that sound absorption properties of composites increased at the whole range of frequency compared to those of needle-punched nonwovens. When loaded with ZrC nano particles, sound absorption properties of composite shifted to a higher frequency region, and with increasing content of ZrC, sound absorption properties were better above 2500 Hz. However, when loaded with TiO₂, sound absorption properties were better at lower frequency. With 3 wt.% TiO₂, sound absorption coefficient reached the best at the frequency range from 500 Hz to 1500 Hz. Besides, 200 nm TiO₂ was more conductive to the increase of sound absorption properties at lower frequency region compared to 10 nm TiO₂. Sound absorption properties of composites with air back cavity shifted to a lower frequency region, too. SEM showed that there was nano particle aggregation when loaded TiO₂ nano particles. XRD showed that ZrC nano particles loaded in PVA nano fiber retained their crystalline structure while TiO₂ didn’t. It appeared from the results that nano particles had an effect on sound absorption materials, with different kinds and different sizes, sound absorption properties will improve in different ranges of frequency     

Preparation and characterization of Ceftazidime loaded electrospun silk fibroin/gelatin mat for wound dressing

Fabrication of Ceftazidime (CTZ) loaded silk fibroin/gelatin (SF/GT) nanofibers (NFs) without the loss of structure and bioactivity of CTZ was demonstrated by electrospinning method. The structure, morphology and mechanical properties of the electrospun SF/GT nanofibrous mats were characterized using FT-IR, SEM and DSC. The drug release profile of different electrospun fibers was analyzed using spectrophotometric method, and also diffusion method was applied to assess the antibacterial effect of NFs. Cell viability was evaluated by MTT assay. The results show that the average diameter of drug loaded NFs at the optimum polymer to drug feeding ratio (10:1) was 276.55±35.8 nm, while increasing the feeding ratio to 1:1 increases the average diameter to 825.02±70.3 nm. FT-IR of drug loaded NFs was revealed that CTZ was successfully encapsulated into NFs while viability study approved cytocompatibility of SF/GT NFs. CTZ was released from NFs during 6 h, and formation of inhibition zone in diffusion test demonstrated the antibacterial effect of drug loaded NFs. Altogether, the CTZ loaded SF/GT NFs can improve the drug effectiveness particularly in the prevention of post-surgical adhesions and infections for wound dressing.     

Enzyme inhibitory and antioxidant activity of Melia azedarach L. naturalized in Anatolia and its phenolic acid and fatty acid composition

In the present study, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase inhibitory and antioxidant activities of the fruit and leaf extracts of Melia azedarach L. (Meliaceae) of Turkish origin were evaluated. Enzyme inhibitory activity of the extracts was tested in vitro using ELISA microplate reader. Antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferrous ion-chelation, and ferric-reducing antioxidant power (FRAP) assays. Phenolic composition of the extracts was elucidated by high performance liquid chromatography (HPLC) and fatty acid compositions of the fatty oils of the fruits and leaves were elucidated by gas chromatography-mass spectrometry (GC-MS). The ethyl acetate extract from the leaves showed the highest inhibition against AChE (33.63 ± 1.40%) and BChE (92.89 ± 3.05%). The methanol extract from the leaves exerted the best antioxidant activity in DPPH radical scavenging and FRAP assays, while the ethyl acetate extracts of the fruits and leaves had the most notable effect in metal-chelation assay.     

Carbon nanofiber/poly(vinylidene fluoride-hexafluoro propylene) composite films: The crystal structure and thermal properties with various drawing temperatures

Carbon nanofiber (CNF)/polyvinylidene fluoride-hexafluoro propylene (PVDF-HFP) composite film was prepared by solution casting and melt pressing. The resultant 2 % CNF/PVDF-HFP composite films were uniaxially drawn at 50 °C, 75 °C, and 100 °C, respectively. In the SEM images, the morphology of drawn CNF/PVDF-HFP composite film confirmed the orientation of the CNF and the polymer matrix. The WAXD results showed the coexistence crystal phase of PVDF-HFP. The drawn CNF/PVDF-HFP composite film demonstrates improved electrical properties. The DSC thermogram results indicated no change in the melting temperature but slightly increased crystallinity with increasing drawing temperature. Dynamic mechanical analysis and tensile test showed an improvement in the storage modulus and stress at a drawing temperature of 75 °C.     

茶叶品质性状的构成与评价

一、茶叶品质和品质评价的概念所谓茶叶品质,一般指茶叶的色、香、味、形与叶底,是茶叶产品所具备的满足人们需要的属性,即茶叶的使用价值。茶叶品质评价是对茶叶产品的属性,即卫生品质、加工品质、保健品质、商品品质等方面进行客观、定量和标准的分析过程,从而对茶叶质量作综合评价。茶叶产品根据加工方法不同和品质上的差异,分为绿茶、红茶、乌龙茶、白茶、黑茶、黄茶六大茶类和再加工茶,茶叶产品种类繁多,产品各异。20世纪70年代以来,人们尝试采用机器视觉技术、人工神经网络技术、电子鼻、电子舌、化学指纹图谱等手段对茶叶品质进行评价。但目前在国内外,茶叶品质的优劣大多数是通过人的感官评定的,其原因是由于茶叶的品质成分组成复杂,无法通过某种成分的量化表达。     

Bioscouring of cotton fabrics using pectinase enzyme its optimization and comparison with conventional scouring process

The conventional scouring process involving the harsh environment is slowly being replaced with environment friendly approach using enzymes. These enzymes remove the non cellulosic impurities present in the fabric. Such a process would enhance the absorbency of the fabric without appreciable strength loss and also would help in the proper dyeing and finishing of the fabric. In the present work pectinase enzyme was isolated from Fusariumn sp. and was optimized under different cultural conditions. The partially purified pectinase enzyme was used in the scouring of cotton fabric. The efficiency of the bioscoured cotton fabric was compared with that of the conventionally scoured fabric. It was found that the water absorbing character of the bioscoured fabric was found to be considerably higher than that of the conventionally scoured fabric. Also, the tensile strength of the cotton fabric was found to be higher for the sample treated using pectinase enzyme than the sample treated conventionally. The results of FTIR confer that the pectin and wax impurities were removed from the cotton surface in both the conventionally scoured and bioscoured fabrics.     

A comparison of grass/white clover and grass silages offered to dairy cows as the sole feed

Two diets were compared: perennial ryegrass ( Lolium perenne L.) silage and perennial ryegrass/white clover ( Trifolium repens L.) silage, in each case fed ad libitum , without supplementation, to lactating dairy cows. The comparison was made with silages cut on each of four dates. The crops were wilted to a dry matter content of at least 256g kg^-1 and no additives were used.
The grass/clover silages were well preserved at all four cuts. The grass was well preserved at three cuts, but, at a May cut, the grass silage was less well preserved and less digestible than the grass/clover silage. When the May silages were fed, milk yield was higher with grass/clover than with grass. Taking the experiment as a whole, however, milk yield and composition were similar on the two diets. The grass/clover silages had a lower proportion of cell wall and their intake by dairy cows was consistently higher than that of the grass silages.
It is concluded that perennial ryegrass/white clover crops can be ensiled successfully and fed successfully, with high intake, to lactating dairy cows, but it should not be assumed that cows will give more milk than when fed equivalent all-grass silage.     

Process technology and properties evaluation of a chitosan-coated Tencel/cotton nonwoven fabric as a wound dressing

A double-layer nonwoven fabric containing Tencel, cotton, and chitosan was prepared by the immersion-precipitation phase-inversion method and evaluated as a wound covering. Macroporous structure of the chitosan membrane could control evaporative water loss, promote fluid drainage, and inhibit exogenous micro-organisms invasion due to inherent antimicrobial property of the chitosan. The chitosan membrane was hemostatic and could accelerate the healing of the wound. Histological examination showed that epithelialization rate was increased and the deposition of collagen in the dermis was well organized by covering the wound with the membrane. These results indicate that the chitosan-coated Tencel/cotton nonwoven fabric can be a potential material employed as a wound dressing.     

Variation in oil content and fatty acid profile of Calophyllum inophyllum L. with fruit maturity and its implications on resultant biodiesel quality

Variation in oil content and fatty acid profile (FAP) of Calophyllum inophyllum; a potential biodiesel feedstock species were studied at different maturity stages and biodiesel quality parameters were estimated based on the FAP. A steady increase in oil content was observed with maturity. Variation in palmitic (16:0) and linoleic (18:2) acids followed exactly opposite trends where palmitic acid content has decreased and linoleic acid content has increased 77 days after anthesis. Oleic acid (18:1) content has shown a steady increase. Stearic acid (18:0) content remained steady up to 68 days after anthesis and then felt slightly in 77 days after anthesis. Linoleic and eicosanoic acids were found to exist in low concentrations demonstrated very little compositional variation with fruit maturity. Estimated biodiesel parameters of all maturity stages were found to comply with industrial standards. Even though 48 days after anthesis had the most ideal FAP for biodiesel production, ∼77 days after anthesis is preferred point to harvest due to higher oil content.