Miscibility, structural characteristics, and thermal behavior of wet spun regenerated silk fibroin/nylon 6 blend filaments     

Jae Sang Ko  Kee Hoon Lee  Do Gyu Bae  In Chul Um 《Fibers and Polymers》2010,11(1):14-20

In this study, the regenerated silk fibroin (SF)/nylon 6 blend filaments were fabricated by the wet spinning and miscibility, structural characteristics, and thermal behavior of blend filaments were elucidated. The XRD results implied that the amount of crystalline region of each polymer did not change linearly with the blend ratio suggesting that there are some changes in the miscibility depending on the mixing ratio. The SEM observation revealed that the miscibility of blend decreased with an increase of nylon 6 resulting in a severe phase separation in 50/50 SF/nylon 6 filament. The miscibility governed the thermal behavior of blend filaments. The melting point of nylon 6 remained constant until 50 % nylon 6 content, whereas the melting point depression appeared in 30 % nylon 6 implying miscibility. Interestingly, the thermal decomposition of the nylon 6 component was accelerated by the presence of SF and the acceleration action of SF became stronger as the miscibility increased.  相似文献   

Improvement of Sponge Cake Baking Test Procedure for Simple and Reliable Estimation of Soft White Wheat Quality     

Hyun‐Wook Choi  Tracy Harris  Byung‐Kee Baik 《Cereal Chemistry》2012,89(2):73-78

The sponge cake baking test is accepted and routinely used as a standard quality evaluation tool of soft white wheat for Asian markets, but its lengthy and laborious procedure makes it unsuitable for the routine evaluation of a large number of wheat breeding lines. We simplified the sponge cake baking procedure in the egg‐whipping step and improved its consistency by replacement of the hand mixing of cake batter with mechanical mixing, using a wire whisk or a BeaterBlade paddle. Egg whipping and mechanical batter mixing conditions were optimized by comparing foam density, sponge cake volume, and crumb grain to those obtained by the conventional procedure. Foam density, sponge cake volume, and crumb grain comparable to the conventional 100 g flour procedure were obtained with modifications, including extension of whipping time without heat input using a 5 L KitchenAid mixer, one‐time water addition at 3 min before the completion of egg whipping instead of twice, as in the conventional procedure, and cake batter mixing with a KitchenAid wire whisk or a BeaterBlade paddle. For baking a 50 g flour cake, egg foam of appropriate density was obtained with increased whipping speed and shortened egg‐whipping time (8 min). The modified sponge cake baking procedure yielded egg‐foam density, cake volume, and crumb grain similar to the conventional procedure and effectively differentiated soft wheat flours of different quality. Sponge cake volume of 14 soft white wheat flours ranged from 1,134 to 1,426 mL with the conventional procedure, from 1,113 to 1,333 mL with the modified procedure of batter mixing with a wire whisk, from 1,108 to 1,360 mL with the modified procedure of batter mixing with a BeaterBlade paddle, and from 577 to 719 mL with the modified method of 50 g of flour and batter mixing with a wire whisk. The modified methods with the BeaterBlade paddle and wire whisk exhibited significant correlation in cake volume with a conventional procedure (r = 0.931, P < 0.001 and r = 0.925, P < 0.001, respectively).  相似文献   

Acid-sensitivity and physical properties of polymethylmethacrylate and polyurethane films containing polymeric styryl dye     

Jae?Whan?ChoEmail author  Sun?Hwa?Lee  Jung?Hyun?So  Jae?Yun?Jaung  Kee?Jong?Yoon 《Fibers and Polymers》2004,5(3):239-244

Solution-cast films of polymethylmethacrylate (PMMA) and polyurethane (PU) containing polymeric styryl dye up to 5% by weight were prepared to investigate their acid-sensitivity and mechanical and thermal properties. Original red samples due to styryl dye turned out yellow very rapidly as they were exposed to acid vapor of hydrochloric acid or p-toluenesulfonic acid. According to UV/VIS spectroscopic measurements, characteristic peak intensities near 430 nm and 520 nm increased or decreased relatively with exposed amounts of acid, respectively. Both PMMA and PU samples showed uniform color distribution due to a good miscibility between polymer and dye which can be evidenced by measurements of glass transition temperature. No significant difference in acid-sensitivity was found between PU and PMMA except relative absorbance. However, dependence of their mechanical properties on dye content was somewhat different with PU or PMMA. In case of PMMA, modulus and breaking stress increased up to about 50% with increasing dye content, whereas those of PU samples showed only slight increase. It was ascribed to whether the matrix polymer was in the glassy or rubbery state.  相似文献   

The development of a novel percutaneous lung biopsy procedure for use on feedlot steers     

Burgess BA  Hendrick SH  Pollock CM  Abutarbush SM  Vogstad A  Jim GK  Booker CW 《Canadian journal of veterinary research》2011,75(4):254-260

The purpose of this study was to develop a percutaneous lung biopsy technique to be used on steers in a commercial feedlot setting. Thirty-four crossbred steer and heifer calves from a commercial feedlot in southern Alberta were used in this study. The calves originated from the auction market and all were chronically affected with bovine respiratory disease (BRD). A technique was developed to obtain a lung sample from the right cranioventral lung lobe, intercostal space (ICS) 2, using a manual or an automatic biopsy instrument with a 14- or 12-gauge (ga) biopsy needle. Overall, lung parenchyma was successfully harvested in 55.9% of experimental animals and in 55.0% of lung biopsy trials. Compared with postmortem diagnosis, the biopsy resulted in the same pathologic diagnosis for 75% of biopsy samples when evaluated using standardized criteria by the same veterinary pathologist. The success rate was 61.5% and 42.9% in a hospital or field setting, respectively. With an automatic instrument, lung was recovered from 57.9% and 37.5% of samples obtained using a 12- or 14-ga biopsy needle, respectively. One experimental animal or 2.9% of the total had fatal complications from the procedure. In a commercial feedlot setting, the procedure took 20 min for each animal. Percutaneous lung biopsy of the right cranioventral lung lobe may be a viable technique when used on feedlot steers affected with chronic pneumonia. These findings suggest that using an automatic instrument with either a 14- or 12-ga biopsy needle may yield lung samples that are suitable for histopathological evaluation. However, this technique needs to be further evaluated in a field setting.  相似文献   

Absorption, translocation, and metabolism of propoxycarbazone-sodium in ALS-inhibitor resistant Bromus tectorum biotypes     

Kee Woong Park 《Pesticide biochemistry and physiology》2004,79(1):18-24

Experiments were conducted to investigate the absorption, translocation, and metabolism of propoxycarbazone-sodium in acetolactate synthase-inhibitor resistant (AR and MR) and susceptible (AS and MS) Bromus tectorum biotypes. Absorption and translocation of ^l4C-propoxycarbazone-sodium were similar in all biotypes. One major and three minor metabolites were identified using reverse-phase high performance liquid chromatography. In all biotypes, 80% of the propoxycarbazone-sodium was metabolized by 72 h after treatment (HAT). However, propoxycarbazone-sodium was metabolized more rapidly in the MR biotype than in the other biotypes. The half-life of propoxycarbazone-sodium in the MR biotype was 8.9 h, which was 30, 36, and 40% shorter than in the AS, AR, and MS biotypes, respectively. When ¹⁴C-propoxycarbazone-sodium was applied with 1-aminobenzotriazole, a known cytochrome P450 inhibitor, metabolism decreased 20% 12 HAT in the MR biotype. These results indicate that resistance of the MR biotype to propoxycarbazone-sodium is due to a relatively rapid rate of propoxycarbazone-sodium metabolism compared to other B. tectorum biotypes and that cytochrome P450s may be involved in the metabolism. The fact that these populations evolved so quickly and with different resistance mechanisms is a concern as more ALS inhibitors are introduced into the production systems.  相似文献   

An evaluation of the relative efficacy of a new formulation of oxytetracycline for the treatment of undifferentiated fever in feedlot calves in western Canada          下载免费PDF全文

Schunicht OC  Booker CW  Guichon PT  Jim GK  Wildman BK  Hill BW  Ward TI  Bauck SW 《The Canadian veterinary journal. La revue veterinaire canadienne》2002,43(12):940-945

A field trial was performed under commercial feedlot conditions in western Canada to compare the efficacy of a new formulation of long-acting oxytetracycline (LA 30) to a standard long-acting oxytetracycline formulation (LA 20) and florfenicol (FLOR) for the treatment of undifferentiated fever (UF) in calves that received metaphylactic tilmicosin upon arrival at the feed-lot. Seven hundred and ninety-seven recently weaned, auction market derived, crossbred, beef calves suffering from UF were allocated to 1 of 3 experimental groups as follows: LA 30, which received intramuscular long-acting oxytetracycline (300 mg/mL formulation) at the rate of 30 mg/kg body weight (BW) at the time of allocation; LA 20, which received intramuscular long-acting oxytetracycline (200 mg/mL formulation) at the rate of 20 mg/kg BW at the time of allocation; or FLOR, which received intramuscular florfenicol administered at the rate of 20 mg/kg BW at the time of allocation and again 48 hours later. Two hundred and sixty-six animals were allocated to the LA 30 group, 265 animals were allocated to the LA 20 group, and 266 animals were allocated to the FLOR group. The relative efficacy of the LA 30 group, as compared with the LA 20 and FLOR groups, was assessed by comparing relapse, chronicity, wastage, and mortality rates. The overall mortality (RR = 0.50) rate in the LA 30 group was significantly (P < 0.05) lower than in the LA 20 group. However, the overall chronicity (RR = 2.56) and overall wastage (RR = 6.97) rates of the LA 30 group were significantly (P < 0.05) higher than in the LA 20 group. There were no significant (P > or = 0.05) differences in UF relapse rates or cause specific mortality rates between the LA 30 and LA 20 groups. In the economic analysis, there was an advantage of $28.59 CDN per animal in the LA 30 group compared with the LA 20 group. The overall chronicity (RR = 2.25) and overall wastage (RR = 2.80) rates of the LA 30 group were significantly (P < 0.05) higher than the FLOR group. There were no significant (P > or = 0.05) differences in UF relapse rates, overall mortality rates, or cause specific mortality rates between the LA 30 and FLOR groups. In the economic analysis, there was an advantage of $12.90 CDN per animal in the LA 30 group compared with the FLOR group. In summary, the results of this study indicate that it is more cost-effective to use a new formulation of long-acting oxytetracycline (300 mg/mL formulation administered at a rate of 30 mg/kg BW) than a standard long-acting oxytetracycline formulation (200 mg/mL formulation administered at a rate of 20 mg/kg BW) or florfenicol for the treatment of UF in feedlot calves that have previously received metaphylactic tilmicosin upon arrival at the feedlot.  相似文献   

Microbiological and histopathological findings in cases of fatal bovine respiratory disease of feedlot cattle in Western Canada   总被引：1，自引：0，他引：1  

Booker CW  Abutarbush SM  Morley PS  Jim GK  Pittman TJ  Schunicht OC  Perrett T  Wildman BK  Fenton RK  Guichon PT  Janzen ED 《The Canadian veterinary journal. La revue veterinaire canadienne》2008,49(5):473-481

The aim of this study was to describe the microbiologic agents and pathologic processes in fatal bovine respiratory disease (BRD) of feedlot cattle and to investigate associations between agents and pathologic processes. Ninety feedlot calves diagnosed at necropsy with BRD and 9 control calves without BRD were examined, using immunohistochemical (IHC) staining and histopathologic studies. Mannheimia haemolytica (MH) (peracute, acute, and subacute cases) and Mycoplasma bovis (MB) (subacute, bronchiolar, and chronic cases) were the most common agents identified in fatal BRD cases. Significant associations (P < 0.10) were detected between microbiologic agents and between agents and pathologic processes. When IHC staining was used, 25/26 (96%) of animals that were positive for bovine viral diarrhea virus (BVDV) were also positive for MH; 12/15 (80 %) of animals that were positive for Histophilus somni (HS) were also positive for MB; and all of the animals that were positive for HS were negative for MH and BVDV. This quantitative pathological study demonstrates that several etiologic agents and pathologic processes are involved in fatal BRD of feedlot cattle.  相似文献   

Effects of Postharvest Processing on Texture Profile Analysis of Cooked Rice     

Elaine T. Champagne  Brenda G. Lyon  Bong Kee Min  Bryan T. Vinyard  Karen L. Bett  Franklin E. Barton  Bill D. Webb  Anna M. McClung  Karen A. Moldenhauer  Steve Linscombe  Kent S. McKenzie  David E. Kohlwey 《Cereal Chemistry》1998,75(2):181-186

The effects of drying conditions, final moisture content, and degree of milling on the texture of cooked rice varieties, as measured by texture profile analysis, were investigated. Instrumentally measured textural properties were not significantly (α = 0.05) affected by drying conditions, with the exception of cohesiveness. Cohesiveness was lower in rice dried at lower temperatures (18°C or ambient) than in that dried at the higher commercial temperatures. Final moisture content and degree of milling significantly (α = 0.05) affected textural property values for adhesiveness, cohesiveness, hardness, and springiness; their effects were interdependent. The effects of deep milling were more pronounced in the rice dried to 15% moisture than that dried to 12%. In general, textural property values for hardness were higher and those for cohesiveness, adhesiveness, and springiness were lower in regular-milled rice dried to 15% moisture than in that dried to 12%. In contrast, hardness values were lower and cohesiveness, adhesiveness, and springiness values were higher in deep-milled rice dried to 15% moisture than in that dried to 12% moisture. Deep milling resulted in rice with lower hardness values and higher cohesiveness, adhesiveness, and springiness values.  相似文献   

Morphology,phylogeny and pathogenicity of Fusarium species from Sansevieria trifasciata in Malaysia     

Yee Jia Kee  Latiffah Zakaria  Masratul Hawa Mohd 《Plant pathology》2020,69(3):442-454

Leaf blight is a common disease affecting Sansevieria trifasciata in many countries, including Malaysia. In the present study, Fusarium isolates were consistently recovered from the diseased leaves collected from various locations throughout the country. Based on morphology and multigene phylogenetic analysis using mitochondrial small subunit (mtSSU), intergenic spacer region (IGS) and translation elongation factor 1-α (TEF1-α) gene sequences, seven Fusarium species were identified, with F. oxysporum being the most prevalent (67.6%) among 34 isolates. Pathogenicity tests resulted in the discovery of pathogenic isolates that belonged to F. oxysporum, F. proliferatum, and F. pseudocircinatum, whereas all isolates of F. brachygibbosum, F. concentricum, F. mangiferae, and F. solani were nonpathogenic. The results suggest that several Fusarium species are accountable for causing disease on S. trifasciata in Malaysia.  相似文献   

Extrusion of Regular and Waxy Barley Flours for Production of Expanded Cereals     

Byung‐Kee Baik  Joseph Powers  Linhda T. Nguyen 《Cereal Chemistry》2004,81(1):94-99

Grains of two regular and two waxy barley cultivars were milled into break and reduction stream flours using a wheat milling mill, granulated to facilitate feeding and flow through the barrel, and extruded to form expanded products using a modified laboratory single‐screw extruder. As moisture content of barley granules decreased from 21 to 17%, the expansion index of extrudates increased from 1.81 to 2.68, while apparent modulus of compression work (AMCW) decreased from 17.1 × 10⁴ to 7.8 × 10⁴ N/m². Break stream flours of both regular and waxy barley produced extrudates with higher expansion index (2.72–3.02), higher water absorption index (WAI), and lower AMCW than extrudates from reduction stream flours. Extrudates produced from regular barley had generally higher expansion and lower density than those produced from waxy barley. The specific mechanical energy (SME) was greater during extrusion of regular than of waxy barley. Barrel temperatures of 130, 150, and 170°C for the feeding, compression, and metering sections, respectively, resulted in higher SME, higher expansion index, lower water absorption index and lower AMCW of extrudates compared with a constant extruder barrel temperature of 160°C. Increased screw speed generally resulted in larger expansion index and increased WAI of extrudates. With increased feed rate from 89 to 96 g/min, the expansion index of extrudates decreased from 3.20 to 2.78 in regular barley and 3.23 to 2.72 in waxy barley, and harder extrudates were produced.  相似文献