854 research outputs found
Simulating dioxane transport in a heterogeneous glacial aquifer system (Washtenaw County, Michigan) using publicly available models and data
The primary challenge in groundwater and contaminant transport modeling is obtaining the data needed for constructing, calibrating and testing the models. Large amounts of data are necessary for describing the hydrostratigraphy in areas with complex geology. Increasingly states are making spatial data available that can be used for input to groundwater flow models. The appropriateness of this data for large-scale flow systems has not been tested. This study focuses on modeling a plume of 1,4-dioxane in a heterogeneous aquifer system in Scio Township, Washtenaw County, Michigan. The analysis consisted of: (1) characterization of hydrogeology of the area and construction of a conceptual model based on publicly available spatial data, (2) development and calibration of a regional flow model for the site, (3) conversion of the regional model to a more highly resolved local model, (4) simulation of the dioxane plume, and (5) evaluation of the model\u27s ability to simulate field data and estimation of the possible dioxane sources and subsequent migration until maximum concentrations are at or below the Michigan Department of Environmental Quality\u27s residential cleanup standard for groundwater (85 ppb). MODFLOW-2000 and MT3D programs were utilized to simulate the groundwater flow and the development and movement of the 1, 4-dioxane plume, respectively. MODFLOW simulates transient groundwater flow in a quasi-3-dimensional sense, subject to a variety of boundary conditions that can simulate recharge, pumping, and surface-/groundwater interactions. MT3D simulates solute advection with groundwater flow (using the flow solution from MODFLOW), dispersion, source/sink mixing, and chemical reaction of contaminants. This modeling approach was successful at simulating the groundwater flows by calibrating recharge and hydraulic conductivities. The plume transport was adequately simulated using literature dispersivity and sorption coefficients, although the plume geometries were not well constrained
The assessment of HIV knowledge and attitudes towards caring for HIV/AIDS patients among senior nursing students in baccalaureate programs in the United States of America and Thailand
Title from title screen of research.pdf file (viewed on August 10, 2007)"December 2006"The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Vita.Appendices in Thai.Thesis (Ph. D.) University of Missouri-Columbia 2006.This study uses a descriptive, comparative design to examine, describe, and compare HIV knowledge and attitudes towards caring for HIV/AIDS patients among senior baccalaureate nursing students in the United States of America and Thailand. Either the English or the Thai version of HIV Knowledge Questionnaire (HIV-KQ 45), AIDS Attitude Scale (AAS), and the Caring Survey were administered. Participants of this study come from convenience samples from the schools of nursing at the four universities: 49 U.S senior nursing students at New York University, 50 U.S. senior nursing students at University of Missouri-Columbia, 50 Thai senior nursing students at Chiang-Mai University, and 55 Thai senior nursing students at Prince of Songkla University. The key findings identified that U.S. students, regardless of HIV/AIDS prevalence area, had significantly greater HIV/AIDS knowledge than Thai students. Only the U.S. students practicing in the high HIV/AIDS prevalence area had significantly better attitude and caring scores compared to Thai students who [are] also practicing in the high HIV/AIDS prevalence area.Includes bibliographical reference
Impact Of Pulsed Electric Field Pretreatment On Yield And Quality Of Lipid Extracted From Cephalothorax Of Pacific White Shrimp (Litopenaeus Vannamei) By Ultrasound Assisted Process
Impacts of pulsed electric field (PEF) pretreatment with different electric field strengths (4, 8, 12 and 16 kVcm-1 ) and pulse numbers (120, 160, 200 and 240) on extraction yield of lipid and cell disintegration index (Zc) of Pacific white shrimp cephalothorax were examined. PEF treated samples were subsequently subjected to lipid extraction using ultrasonic assisted extraction (UAE) process at ultrasonic amplitude of 91.2 microns for 25 min in continuous mode. Samples with PEF pretreatment and subjected to UAE rendered the highest lipid yield (30.34% dry basis). PEF pretreatment resulted in suppression of lipid oxidation as affirmed by the decreases in peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Lipid from PEF pretreated samples had higher content of PUFAs as well as carotenoids, which included astaxanthin, astaxanthin monoester, astaxanthin diester, canthaxanthin and β-carotene. Overall, PEF was a promising pretreatment to increase the yield and maintain the quality of lipid extracted from cephalothorax using UAE
Biochemical and microstructural characteristics of meat samples treated with different plant proteases
This study was conducted to compare the efficiency of different plant proteases for changing biochemical and microstructural characteristics in muscle foods. The meat samples from chicken, giant catfish, pork and beef were treated with four types of proteolytic enzymes: Calotropis procera latex proteases, papaya latex proteases, commercial papain and bromelain at the concentrations of 2 × 103 to 6 × 103 activity units/100 g of muscle. The pH, collagen solubility, trichloroacetic acid (TCA) soluble peptides, protein patterns and muscle microstructures of the treated samples were evaluated after 24 h at 4°C. A decrease of muscle pH in chicken, giant catfish and pork was observed when the enzymes were added (p < 0.05). A significant increase in collagen solubility was also found in all of the muscle samples (chicken increased from 37.64 to 83.59%; giant catfish increased from 52.82 to 84.14%; pork increased from 14.34 to 86.78; and beef increased from 26.02 to 86.18%; p < 0.05). An increase in TCA-soluble peptides (from 0.90 to18.53 μmole/g sample), and myofibrillar protein degradation was observed in all of the enzyme treated samples as compared to the control (p < 0.05). The electrophoretic pattern of the muscle proteins also revealed extensive proteolysis and reduction of protein bands in all of the treated samples. At the microstructural level, tissue fibers were broken, and the connections between the sarcolemma and the myofibrils were loosened when each enzyme was applied. When comparing all proteolytic enzymes used, papaya latex proteases showed the highest hydrolysis activity in all muscle types, which was followed by C. procera latex proteases, commercial papain, and then bromelain. The results show that these proteolytic enzymes could be used as an effective meat tenderizer.Key words: Proteases, muscle foods, collagen, tenderization, toughness
Effect of pulsed electric field treatments on melanosis and quality changes of Pacific white shrimp during refrigerated storage
Polyphenoloxidase (PPO) from Pacific white shrimp was subjected to Pulsed electric field (PEF) at varying specific energy (54-483 kJ/kg) and pulse number (200-600). PPO activity was decreased as both parameters increased (P < 0.05). Among shrimp treated with PEF, those subjected to PEF-T3 (483 kJ/kg, 600 pulses) had the lower melanosis score than other PEF treatments and the control, packaged in polystyrene trays and wrapped with shrink film, during 10 days of storage at 4 °C (P < 0.05). Highest shear force values were noticed with PEF-T3 treated sample at the end of storage period (day 10) (P < 0.05). Microstructural gaping between shrimp muscle fibers was notably higher in PEF-T3. No protein degradation was observed for all samples, regardless of PEF treatments. Lower mesophilic and psychrophilic microbial counts in shrimp were obtained when PEF-T3 was implemented. After 10 days of storage, higher sensory scores of PEF-T3 treated samples were also attained, as compared to others (P < 0.05). Quality deterioration of shrimp was retarded with the aid of PEF
Monoclonal antibodies specific to heat-treated porcine blood
BACKGROUND: Porcine blood is potentially being utilized in food as a binder, gelling agent, emulsifier or colorant. However, for certain communities, the usage of animal blood in food is strictly prohibited owing to religious concerns and health reasons. This study reports the development of monoclonal antibodies (MAbs) against heat-treated soluble proteins (HSPs) of autoclaved porcine blood; characterization of MAbs against blood, non-blood and plasma from different animal species using qualitative indirect non-competitive enzyme-linked immunosorbent assay (ELISA); and immunoblotting of antigenic components in HSPs of porcine blood.
RESULTS: Fifteen MAbs are specific to heat-treated and raw porcine blood and not cross-reacted with other animal blood and non-blood proteins (meat and non-meat). Twelve MAbs are specific to porcine plasma, while three MAbs specific to porcine plasma are cross-reacted with chicken plasma. Immunoblotting revealed antigenic protein bands (∼60, ∼85–100 and ∼250 kDa) in porcine blood and plasma recognized by the MAbs.
CONCLUSION: Selection of MAbs that recognized 60 kDa HSPs of porcine blood and plasma as novel monoclonal antibodies would be useful for detection of porcine plasma in processed food using the immunoassay method
Antimicrobial activity of some potential active compounds against food spoilage microorganisms
Antimicrobial activities of six potential active compounds (acetic acid, chitosan, catechin, gallic acid, lysozyme, and nisin) at the concentration of 500 g/ml against the growth of Escherichia coli, Staphylococcus aureus, Listeria innocua, and Saccharomyces cerevisiae were determined. Lysozyme showed the highest antimicrobial activity against L. innocua and S. cerevisiae with an inhibition zone of 19.75 and 17.37 mm, respectively. Catechin was strongly active against E. coli, L. innocua, and S. aureus with 15.37, 19.38, and 17.00 mm of inhibition zone diameter, respectively. The minimum inhibitory concentration (MIC) value of catechin for E. coli and for S. aureus was the same at 640 μg/ml, while the minimum bactericidal concentration (MBC) values were 640 and 1,280 μg/ml, respectively. The MIC and MBC values of lysozyme for L. innocua were 160 and 640 μg/ml, respectively. S. cerevisiae was the most susceptible microorganism to lysozyme among others, since both its MIC and MBC were the lowest (2.5 μg/ml). However, catechin and lysozyme were combined in equal amounts; all tested microorganisms were effectively inhibited as indicated by both qualitative and quantitative antimicrobial activities. This study thus revealed the potential application of some active compounds such as catechin and lysozyme for their usage in food products.Keywords: Antimicrobial activity, catechin, lysozyme, agar disc diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC
En eksplorativ studie av thailandske etterkommeres erfaringer og utviklingsmuligheter i Norge
Familie immigrasjon er en av de største formene for migrasjon av thailendere i Norge, spesielt mødre som har migrert via et transnasjonalt ekteskap. Likeledes har beslutning om vært styrende fra den migrerende forelder, mens barnets ønsker om å migrere har blitt oversett. Det er lite informasjon om livene deres etter de har blitt flyttet til et annet land. Med dette og mangelen på tilgjengelig litteratur, blir hovedformålet til denne studien å utforske erfaringer og utviklingsmuligheter som tha
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Utilization of wastes from Pacific whiting surimi manufacturing : proteinases and protein hydrolysate
Both liquid and solid wastes from Pacific whiting surimi manufacturing were
characterized and value-added products were recovered. A proteinase in surimi wash
water (SWW) was determined to be cathepsin L with Mr 54,200 on SDS-substrate gel.
Heat treatment and acidification shifted the activity zone to M [subscript r] 39,500. No evidence of
calpain, cathepsin B or H activity was found. Cathepsin L from SWW was recovered
by ohmic heating (55°C for 3 min), ultrafiltration, and freeze-drying with overall yield
of 0.83 g protein/L SWW and 78% recovery of activity. A 5.9 purification fold was
achieved by these processes. The recovered enzyme had an optimum activity at pH 4.0
and showed preferable hydrolytic activity towards casein, acid-denatured hemoglobin and
myofibrils. β-Mercaptoethanol, dithiothreitol and urea enhanced the enzyme
activity. The recovered proteinase showed 18.5% residual activity after
7 wk storage at 4°C.
Proteolytic activity in solid waste and digestive organs from Pacific whiting was
investigated. Pepsin-like proteinase predominated in solid waste, while trypsin-like
proteinase was predominant in viscera. Carboxypeptidase b was found in both viscera
and solid waste.
Protein hydrolysate was produced from Pacific whiting solid waste (PWSW) using
commercial proteinase, Alcalase, under optimum hydrolysis conditions. Enzyme
concentration, reaction time and waste/buffer ratio affected the hydrolysis and nitrogen
recovery (NR). Correlation between the degree of hydrolysis (DH) and NR was high
(R₂=0.978). Freeze-dried hydrolysate contained 79.97% protein and showed similar
amino acid composition to PWSW and Pacific whiting muscle but tryptophan was
reduced. With different DH (20, 30, 40, 50, 60%), surface hydrophobicity, total and
surface sulfhydryl content decreased as the DH increased. The hydrolysate showed a
high solubility over a wide pH range. Fat adsorption and fat binding capacity were
reduced, while foam expansion was enhanced with an increased DH. Hydrolysate with
DH of 30% showed highest emulsifying activity. Low emulsion stability and high foam
stability were obtained in all hydrolysates tested. Hydrolysate showed antioxidant
activity, but no obvious differences in activity were found with varying DH and
hydrolysate concentrations
Cosmetic potential of marine fish skin collagen
Many cosmetic formulations have collagen as a major component because of its significant benefits as a natural humectant and moisturizer. This industry is constantly looking for innovative, sustainable, and truly efficacious products, so marine collagen based formulations are arising as promising alternatives. A solid description and characterization of this protein is fundamental to guarantee the highest quality of each batch. In the present study, we present an extensive characterization of marine-derived collagen extracted from salmon and codfish skins, targeting its inclusion as component in cosmetic formulations. Chemical and physical characterizations were performed using several techniques such as sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier Transformation Infrared (FTIR) spectroscopy rheology, circular dichroism, X-ray diffraction, humidity uptake, and a biological assessment of the extracts regarding their irritant potential. The results showed an isolation of type I collagen with high purity but with some structural and chemical differences between sources. Collagen demonstrated a good capacity to retain water, thus being suitable for dermal applications as a moisturizer. A topical exposure of collagen in a human reconstructed dermis, as well as the analysis of molecular markers for irritation and inflammation, exhibited no irritant potential. Thus, the isolation of collagen from fish skins for inclusion in dermocosmetic applications may constitute a sustainable and low-cost platform for the biotechnological valorization of fish by-products.The authors would like to acknowledge to European Union for the financial support under the scope of European Regional Development Fund (ERDF) through the projects 0687_NOVOMAR_1_P (POCTEP (Programa Operacional de Cooperação Transfronteiriça España-Portugal) 2007/2013) and 0302_CVMAR_I_1_P (POCTEP 2014/2020) and the Structured Project NORTE-01-0145-FEDER-000021 (Norte2020) and under the scope of the European Union Seventh Framework Programme (FP7/2007-2013) through grant agreement ERC-2012-ADG 20120216-321266 (ERC Advanced Grant ComplexiTE). The Portuguese Foundation for Science and Technology is also acknowledged for the grant of A.L.A (Ana Luísa Alves.) under Doctoral Programme Do* Mar (PD/BD/127995/2016).info:eu-repo/semantics/publishedVersio
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