Molecular mobility of fish flesh measured by low-field nuclear magnetic resonance (LF-NMR) relaxation: effects of freeze–thaw cycles     

Nasser Abdullah Al-Habsi  Sara Al-Hadhrami  Habiba Al-Kasbi  Mohammad Shafiur Rahman 《Fisheries Science》2017,83(5):845-851

In this study, the molecular mobility of fish flesh was measured by low field nuclear magnetic resonance (LF-NMR) relaxation. Sardine, tuna and mackerel were frozen at ?40 °C and stored for 1 day (24 h); and then these samples were thawed at room temperature (20 °C). The relaxation of water protons in fish flesh was measured for fresh (i.e., before freezing) and multi-cycle freeze–thaw samples (i.e., up to 12 times). Three domains from different pools of protons (i.e., low-mobile, medium-mobile and high-mobile) were identified from the relaxation curve. The T _2b (low-mobile), T ₂₁ (medium-mobile) and T ₂₂ (high-mobile) indicated the proton populations in the protein molecules, strongly bound water molecules, and weakly bound water molecules, respectively. In all cases, the relaxation time (T _2b: sardine r = 0.736 and p < 0.01, tuna r = 0.857 and p < 0.001, mackerel r = 0.904 and p < 0.001; and T ₂₂: sardine r = 0.956 and p < 0.0001, tuna r = 0.927 and p < 0.0001, mackerel r = 0.890 and p < 0.0001) increased with the freeze–thaw cycles and it reached a nearly constant value after 6 freeze–thaw cycles. The increased relaxation time (i.e., higher mobility) up to 6 freeze–thaw cycles could be due to the increase in proton mobility. However, relaxation time (T ₂₁: sardine r = ?0.510 and p > 0.05, tuna r = 0.162 and p > 0.5, mackerel r = 0.513 and p > 0.01) showed insignificant change with the increase of freeze–thaw cycles, which indicated minimal change in the medium-mobile protons. The results in this study revealed that the changes in proton mobility in the fish flesh during freeze–thaw cycles could be identified using T _2b and T ₂₂ relaxation of LF-NMR.  相似文献   

Measuring technical,allocative and cost efficiency of pangas (Pangasius hypophthalmus: Sauvage 1878) fish farmers of Bangladesh     

Md Ferdous Alam 《Aquaculture Research》2011,42(10):1487-1500

The present study is conducted to measure the technical (TE), allocative (AE) and cost efficiency (CE) of pangas fish‐producing farmers of Bangladesh. Data envelopment analysis is used to measure the efficiency while Tobit regression is applied to identify the factors affecting efficiencies. The estimated mean TE, AE and CEs are 86%, 62% and 54% respectively. Pangas production is characterized by considerable technical inefficiencies and substantial allocative and cost inefficiencies. Pond size, fingerling size, culture length and use of pelleted feed are important determinants of efficiencies. It is nevertheless profitable in terms of benefit–cost ratio, break‐even yield and price criteria. Production of pangas can be made further profitable by eliminating inefficiencies. Proper mixing of inputs given their prices could make pangas producers profit maximizers. Efficiency improvement is expected to help to increase production and provide scopes for exporting the surplus production. More fisheries extension is suggested to expand pangas culture and improve efficiency.  相似文献   

Ophthalmic findings in a septic calf with the concurrent exhibition of meningitis and endophthalmitis     

Naoaki YOSHIMURA  Takeshi TSUKA  Yuji SUNDEN  Takehito MORITA  Md Shafiqul ISLAM  Osamu YAMATO  Takaaki YOSHIMURA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(11):1648

The aim of this study was to evaluate the impacts of ophthalmic findings obtained from both macroscopic examination and ocular ultrasonography when diagnosing bovine endophthalmitis. A newborn crossbreed (Japanese black and Holstein breeds) calf was suspected of visual impairment and central nervous system (CNS) symptoms, such as decreased activity and weak drinking performance. This calf was found to display macroscopic signs, such as clouded lens, convergent strabismus, and horizontal nystagmus, in both eyes. On ocular ultrasonography of both eyes, a V-shaped, thickened, hyperechoic structure was present in the anechoic vitreous humors, indicating retinal detachment. The animal died 4 days after the examination. Sepsis was evident in this case, as Escherichia coli was isolated from multiple organs. The autopsy and histological examination revealed meningitis, encephalitis, and secondary hydrocephalus in the CNS, and endophthalmitis and retinal detachment in both eyes. In this case, the ophthalmic findings did not provide definitive evidence for a diagnosis of endophthalmitis. However, this study indicated that retinal detachment might be an ultrasonographic finding that is suggestive of bovine endophthalmitis.  相似文献   

A simulation model for fate and transport of methyl bromide during fumigation in plastic‐mulched vegetable soil beds     

Dilip Shinde  Arthur G Hornsby  Robert S Mansell  Mohammad R Savabi 《Pest management science》2000,56(10):899-908

A coupled water‐heat and chemical transport model was used to describe the fate and transport of methyl bromide fumigant in low‐density polyethylene plastic‐mulched soil beds used for vegetable production. Methyl bromide transport was described by convective‐dispersive processes including transformations through hydrolysis. Effects of non‐isothermal conditions on chemical transport were considered through inclusion of temperature effects on transport parameters. An energy‐balance approach was used to describe the plastic‐mulched boundary condition that controls the thermal regime within the soil bed. Simulations were made for variable water‐saturation regimes within the bed and for different depths of fumigant injection. Simulations for various scenarios revealed that large amounts (20–44% over a 7‐day period) of applied methyl bromide are lost from the un‐mulched furrows between the beds. Plastic mulching of the bed was found to be only partially effective (11–29% emission losses over a 7‐day period) in reducing atmospheric emissions. Deep injection of fumigant and saturating the soil with water both led to increased retention of methyl bromide within the soil and less emission to the atmosphere. However, deep injection was unfavorable for effective sterilization of the crop root zone. © 2000 Society of Chemical Industry  相似文献   

Antibacterial properties and color fastness of silk fabric dyed with turmeric extract     

Seyed Majid Ghoreishian  Laleh Maleknia  Hamid Mirzapour  Mohammad Norouzi 《Fibers and Polymers》2013,14(2):201-207

The use of non-toxic and eco-friendly natural dyes on textiles has received much attention due to the increased environmental awareness in order to avoid some hazardous synthetic dyes. In the present study, an eco-friendly approach was developed to impart color and antibacterial properties to silk fabrics dyed with turmeric extract as a non-toxic natural colorant. The natural colorant was extracted from Curcuma Longa rhizome. Copper sulfate, ferrous sulfate and potassium aluminium sulfate were applied in a pre-metallization process as mordanting agents. Antibacterial properties of treated fabrics were evaluated against common pathogenic bacteria, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). The effects of dye concentration and mordant types on the obtained color hues, antibacterial efficiency and color fastness of the fabrics were investigated. The results indicated that mordanted and dyed fabrics possessed desirable antibacterial properties. Complete antibacterial activity of the treated fabrics was obtained with 3 %owf (on weight of the fabric) copper sulfate. It was also shown that increasing the dye concentration could lead to a more efficient antibacterial activity on the mordanted dyed fabrics. An optimum level of the antibacterial activity was observed in the sample treated with 30 %owf of turmeric. Furthermore, the results of CIE L*, a*, b* values, FTIR, washing, light and rubbing fastnesses of the dyed fabrics were reported. The mordanted dyed silk fabrics exhibited desirable color fastness properties. These studies proved a direct relationship between the degree of antibacterial activity of the fabrics treated with turmeric and the metals ion concentration.  相似文献   

Effect of Dioxane and N-Methyl-2-pyrrolidone as a Solvent on Biocompatibility and Degradation Performance of PLGA/nHA Scaffolds     

Neda Aboudzadeh  Alireza Khavandi  Jafar Javadpour  Mohammad Ali Shokrgozar  Mohammad Imani 《Iranian Biomedical Journal》2021,25(6):408

Background:Solvent casting/particulate leaching is one of the most conventional methods for fabricating polymer/ceramic composite scaffolds. In this method, the solvent generally affects resulting scaffold properties, including porosity and degradation rate. Methods:Herein, composite scaffolds of PLGA/nHA with different percentages of nHA (25, 35, and 45 wt. %) were prepared by the solvent casting/particle leaching combined with freeze drying. The effects of two different solvents, DIO and NMP, on morphology, porosity, bioactivity, degradation rate, and biocompatibility of the resulting scaffolds were investigated. Results:The results revealed that increasing the nHA percentages had no significant effect on the porosity and interconectivity of scaffolds (p > 0.05), whereas altering the solvent from DIO into NMP decreased the porosity from about 87% into 71%, respectively. Moreover, scaffolds of DIO illustrated the high results of cell proliferation compared to those of NMP; the cell viability of GD25 decreased from 85% to 65% for GN25. The findings also indicated that scaffolds prepared by NMP had a higher rate of losing weight in comparison to DIO. Adding nHA to PLGA had a significant effect on the bioactivity of scaffolds (p < 0.05), composite scaffolds with 45 wt % nHA had at least 30% more weight gain compared to the neat polymer scaffolds. Conclusion:The DIO scaffolds have higher rates of porosity, interconnectivity, bioactivity, and biocompatibility than NMP scaffolds due to its high evaporation rate. Key Words: Freeze drying, Porosity, Solvents  相似文献   

Extrusion Properties and Cooking Quality of Spaghetti Containing Buckwheat Bran Flour     

Frank A. Manthey  Saujanya R. Yalla  Todd J. Dick  Mohammad Badaruddin 《Cereal Chemistry》2004,81(2):232-236

The effect of hydration level on processing properties and the effects of hydration level, concentration of buckwheat bran flour and drying temperature on the physical and cooking quality of spaghetti were determined. Specific mechanical energy transferred to the dough during extrusion decreased 69% for semolina and 79% for semolina containing 30%, w/w, buckwheat bran flour, as hydration level increased 29–32% absorption. Little or no postdrier checking occurred in spaghetti made from semolina or spaghetti containing buckwheat bran flour when dried at high (70°C) or ultrahigh temperature (90°C). When dried at low temperature (40°C), tolerance to postdrier checking of spaghetti decreased as buckwheat bran flour increased 0–30% (w/w). Hydration level before extrusion did not affect cooking loss of spaghetti made from semolina. However, cooking loss was greater from spaghetti made with semolinabuckwheat bran flour that was hydrated to 32% compared with 29–31% absorption. Cooked firmness of spaghetti containing buckwheat bran flour decreased from 0.588–0.471 Nm as hydration increased from 29–32% absorption. Cooking loss was lower and cooked firmness was greater when spaghetti containing buckwheat bran flour was dried at ultrahigh than at low temperature.  相似文献   

Population genetic structure of <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis> on canola in Iran     

Roghayeh Hemmati  Mohammad Javan-Nikkhah  Celeste C. Linde 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(4):617-628

The genetic structure of 276 Sclerotinia sclerotiorum isolates representing 37 field populations from four provinces in northern Iran were analysed with six polymorphic microsatellite loci. In total, 80 haplotypes were detected with 19 haplotypes (23.7%) shared amongst at least two regional populations. None of the haplotypes were shared among all four regional populations. Of the 80 haplotypes, 32 haplotypes (40%) occurred in low frequencies represented by only one isolate. Moderate levels of gene diversity (H = 0.51 to 0.61) and genotypic diversity (Ĝ = 12.0 to 22.0; clonal fraction = 0.39 to 0.67) for regional populations were observed. Genotypic diversities (Ĝ) did not differ significantly among populations. All regional populations were in linkage equilibrium indicating the occurrence of outcrossing. Low to moderate levels of population subdivision (0.03 to 0.07), were observed among regional populations. Only one large panmictic population was inferred by Structure, indicating no significant population structure. A Mantel test showed no significant isolation by distance (r = −0.43; P = 0.18), indicating anthropogenic movement of inoculum. The results demonstrated that S. sclerotiorum populations in northern Iran, are randomly mating and have a number of shared haplotypes among regional populations; this possibly represents recent founder populations and/or a high occurrence of anthropogenic migration of infected plant material among populations.  相似文献   

Vegetative propagation and initial growth performance of <Emphasis Type="Italic">Stereospermum suaveolens</Emphasis> DC., a wild tropical tree species of medicinal value     

Tarit K. Baul  Mohammad Mezbahuddin  Mohammed Mohiuddin 《New Forests》2009,37(3):275-283

The present study aimed at examining the amenability of Stereospermum suaveolens DC. to vegetative propagation through rooting of leafy stem cuttings using low-cost polythene propagators. Rooting efficiencies of cuttings derived from two selected matured mother trees were studied using four different concentrations of Indole-3-butyric acid (IBA), viz. 0, 0.1, 0.2 and 0.4%. IBA applied at 40 μg per cutting (0.4% concentration) resulted in significantly higher rooting responses compared to the control (P < 0.05). Differences in the length of longest root for all the treatments were significant (P = 0.05) with cuttings treated with 0.2% IBA producing the longest root. The highest survival after 3 weeks of transference of the rooted cuttings into polythene bags was found for rooted cuttings treated with 0.2% IBA. Effects of three fertilizer treatments viz. T₀ (no fertilizer), T₁ (10 g of Urea + 20 g of TSP + 10 g of MOP dissolved in 1 l of water) and T₂ (10 g of Urea + 20 g of TSP + 10 g of MOP dissolved in 2 l of water) on initial growth of established rooted cuttings (stecklings) of Stereospermum suaveolens in polythene bags were also measured for a period of 90 days. Stem length, collar diameter and leaf area of the stecklings increased throughout the observation period. Increments of both stem length and collar diameter were significantly higher for the stecklings treated with T₂ in comparison with the control while increment of leaf area was found the highest for the stecklings treated with T₁. The study clearly indicated that Stereospermum suaveolens is amenable to vegetative propagation technique using juvenile single-node leafy cuttings and the initial growth performance of the established rooted cuttings (stecklings) in polythene bags under different fertilizer treatments was satisfactory.  相似文献   

Electrospinning of silk nanofibers. I. An investigation of nanofiber morphology and process optimization using response surface methodology     

Nasim Amiraliyan  Mahdi Nouri  Mohammad Haghighat Kish 《Fibers and Polymers》2009,10(2):167-176

Ultra fine fibers were electrospun from regenerated silk fibroin/formic acid solution. Effect of some process parameters on the morphology, diameter and variation in fiber diameter of electrospun fibers were experimentally investigated. Scanning electron microscope was used for the measurement of fiber diameter. Fibers with diameter ranging from 80 to 210 nm were collected depending on the solution concentration and the applied voltages. Response surface methodology (RSM) was used to obtain a quantitative relationship between selected electrospinning parameters and the average fiber diameters and its distribution. It was shown that concentration of silk fibroin solution had a significant effect on the fiber diameter and the standard deviation of the fiber diameter. Applied voltage had no significant effect on the fiber diameter and its standard deviation.  相似文献