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1.
Brandon Carter Larissa DiMarzo Joice Pranata David M. Barbano MaryAnne Drake 《Journal of dairy science》2021,104(8):8630-8643
Our objective was to measure whey protein removal percentage from separated sweet whey using spiral-wound (SW) polymeric microfiltration (MF) membranes using a 3-stage, 3× process at 50°C and to compare the performance of polymeric membranes with ceramic membranes. Pasteurized, separated Cheddar cheese whey (1,080 kg) was microfiltered using a polymeric 0.3-μm polyvinylidene (PVDF) fluoride SW membrane and a 3×, 3-stage MF process. Cheese making and whey processing were replicated 3 times. There was no detectable level of lactoferrin and no intact α- or β-casein detected in the MF permeate from the 0.3-μm SW PVDF membranes used in this study. We found BSA and IgG in both the retentate and permeate. The β-lactoglobulin (β-LG) and α-lactalbumin (α-LA) partitioned between retentate and permeate, but β-LG passage through the membrane was retarded more than α-LA because the ratio of β-LG to α-LA was higher in the MF retentate than either in the sweet whey feed or the MF permeate. About 69% of the crude protein present in the pasteurized separated sweet whey was removed using a 3×, 3-stage, 0.3-μm SW PVDF MF process at 50°C compared with 0.1-μm ceramic graded permeability MF that removed about 85% of crude protein from sweet whey. The polymeric SW membranes used in this study achieve approximately 20% lower yield of whey protein isolate (WPI) and a 50% higher yield of whey protein phospholipid concentrate (WPPC) under the same MF processing conditions as ceramic MF membranes used in the comparison study. Total gross revenue from the sale of WPI plus WPPC produced with polymeric versus ceramic membranes is influenced by both the absolute market price for each product and the ratio of market price of these 2 products. The combination of the market price of WPPC versus WPI and the influence of difference in yield of WPPC and WPI produced with polymeric versus ceramic membranes yielded a price ratio of WPPC versus WPI of 0.556 as the cross over point that determined which membrane type achieves higher total gross revenue return from production of these 2 products from separated sweet whey. A complete economic engineering study comparison of the WPI and WPPC manufacturing costs for polymeric versus ceramic MF membranes is needed to determine the effect of membrane material selection on long-term processing costs, which will affect net revenue and profit when the same quantity of sweet whey is processed under various market price conditions. 相似文献
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Emissions and environmental implications of mercury from artisanal gold mining in North Sulawesi,Indonesia 总被引:1,自引:0,他引:1
Limbong D Kumampung J Rimper J Arai T Miyazaki N 《The Science of the total environment》2003,302(1-3):227-236
In artisanal gold mining practiced in North Sulawesi Island, Indonesia, gold is separated from ore by the use of mercury, which forms an amalgam with gold. All related processes are undertaken with a low level of technical knowledge and skills, no regulation, and with disregard for the safety of human and environment health. The situation is generating serious potential health and environmental risks in the area. As part of an ongoing monitoring program, total mercury concentrations were examined in water, bottom sediment and fish samples from three main rivers in Talawaan Watershed, which receives drainage from gold mining practices. Monitoring began in May-June 2000, almost 2 years after artisanal gold mining had begun. At that time, the mercury concentration in the sediment was generally low, except in places close to the gold processing plants. In the present study, a more systematic sampling and analysis was conducted in May-June 2001. Bottom surface sediments, water, and fish samples were collected at 12 sites along the three main rivers in the watershed. In addition, one site outside the watershed was sampled to serve as a control. Sample collections were conducted in three phases in duplicate, with two-week intervals between each phase. The mercury concentration observed in this study indicated that an increase took place along the three main rivers in the watershed. Solutions to this problem must be formulated as soon as possible in order to avoid a major health, economic, and ecological disaster arising from the continuing discharge of Hg. The present study proposes that mercury dispersion occur downstream of the mining. 相似文献
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Palladium complexes of crosslinked polyacrylamide and poly-N-vinylimidazole coated on silica gel have been prepared and used as hydrogenation catalysts for alkenes, dienes and alkynes under ambient conditions. The characterisation of the catalysts, the kinetic and mechanistic aspects of the hydrogenation of a few substrates, the effect of temperature, selectivity and the recycling efficiency of the catalysts are presented. A comparison of their activity is made with other silica supported and silica free polymer-Pd catalysts. 相似文献
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Structure–Activity Relationship of Tumor‐Selective 5‐Substituted 2‐Amino‐3‐carboxymethylthiophene Derivatives
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Dr. Joice Thomas Dr. Alenka Jejcic Peter Vervaeke Prof. Romeo Romagnoli Prof. Sandra Liekens Prof. Jan Balzarini Prof. Wim Dehaen 《ChemMedChem》2014,9(12):2744-2753
Methyl‐2‐amino‐5‐[2‐(4‐methoxyphenethyl)]thiophene‐3‐carboxylate ( 8 c ) is the prototype of a well‐defined class of tumor‐selective agents. Compound 8 c preferentially inhibited the proliferation of a number of tumor cell lines including many human T‐lymphoma/leukemia cells, but also several prostate, renal, central nervous system and liver tumor cell types. Instead, a broad variety of other tumor cell lines including B‐lymphomas and HeLa cells were not affected. The tumor selectivity (TS; selectivity index or preferential suppression of CEM lymphoma (IC50=0.90 μM ) versus HeLa tumor cell carcinoma (IC50=39 μM )) amounted up to ~43 for 8 c . At higher concentrations, the compound proved cytotoxic rather than cytostatic. The antiproliferative potency and selectivity of 8 c could be preserved by replacing the ethyl linker between the 2‐amino‐3‐carboxymethylthiophene and the substituted aryl by a thioalkyl but not by an oxyalkyl nor an aminoalkyl. Among >50 novel 8 c derivatives, the 5‐(4‐ethyl‐ and 4‐isopropylarylmethylthio)thiophene analogues, methyl‐2‐amino‐5‐((4‐ethylphenylthio)methyl)thiophene‐3‐carboxylate ( 13 m ) and methyl‐2‐amino‐5‐((4‐isopropylphenylthio)methyl)thiophene‐3‐carboxylate ( 13 n ), were more potent (IC50: 0.3–0.4 μM ) and selective (TS: 100–144) anti‐T‐lymphoma/leukemia agents than the prototype compound. 相似文献
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The aim of the study was to document the nature and incidence of surgical errors enacted during laparoscopic surgery in order to direct future research and surgical training. A modified Human Reliability Analysis (HRA) approach, based on direct observation, was adopted to categorise and record errors encountered during the practice of laparoscopic cholecystectomy. This study confirmed the applicability and usefulness of an observational methodology in the assessment of human error in endoscopic surgical performance. The study identified aspects of the design and usage of instruments, surgical training and the differences between tasks which needed further directed research in order to identify underlying performance shaping factors (PSFs) and so reduce error rates. 相似文献
8.
Hatha M Vivekanandhan AA Joice GJ Christol 《International journal of food microbiology》2005,98(2):131-134
Motile aeromonads isolated from the intestines of farm-raised freshwater fish such as Catla catla, Labeo rohita and Ctenopharyngodon idella have been characterized to species level. Morphological and physiological grouping revealed 61% Aeromonas hydrophila, 30% Aeromonas caviae, 7% Aeromonas sobria and 2% which remained unidentified. Hemolytic activity was detected mostly in A. hydrophila, while only half of the A. sobria and A. caviae showed this activity. Antibiotic resistance patterns of the strains revealed that they had acquired a relatively higher resistance to oxytetracycline, amoxycillin, ampicillin, novobiocin and polymixin-B, implicating possible use of these antibiotics in the aquaculture systems. 相似文献
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Joice Aline Pires Vilela Ângelo Luiz Fazani CavallieriRosiane Lopes da Cunha 《Food Hydrocolloids》2011
The cold-set gelation of soy protein isolate (SPI)-gellan gum was induced by the addition of salts (KCl or CaCl2) using two different procedures: the direct addition of salts (fast gelation) or the diffusion of salts through a membrane (slow gelation). The mechanical properties, syneresis and microstructure of the mixed gels were evaluated, as well as for gellan and SPI gels. The mixed gels induced by calcium diffusion were stronger and more deformable than gels induced by the direct addition of calcium, while the opposite occurred for potassium-induced gels. All the mixed gels were macroscopically homogeneous, but at the microscopic level two independent networks could be observed. These two separate networks were more evident for the calcium-induced gels, and the structural characteristics depended strongly on the concentration of the protein and the polysaccharide. However an organized microstructure with the formation of microtubes surrounded by other network was only observed for the mixed gels induced by calcium diffusion at the higher protein/polysaccharide (10:1) ratio. Thus besides the composition and concentration of the biopolymers, the results showed that the type of salt and its velocity of incorporation led to gels with different structures and consequently different mechanical properties. 相似文献
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The Nanocrystalline SnO2–TiO2 System‒Part II: Surface Energies and Thermodynamic Stability
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Joice Miagava Andre L. da Silva Alexandra Navrotsky Ricardo H.R. Castro Douglas Gouvêa 《Journal of the American Ceramic Society》2016,99(2):638-644
The thermodynamic stability of nanocrystalline SnO2–TiO2 solid solutions was studied experimentally. Microcalorimetry of water adsorption revealed a systematic decrease in the surface energy with increasing Ti4+ content in the SnO2‐rich compositions, consistent with previous reports of Ti4+ segregation on the surface. The surface energy change was accompanied by an increase in the magnitude of the heat of water adsorption, also indicating a modification of the SnO2 surface by Ti4+. Supporting the water adsorption data, calculations using high‐temperature oxide melt solution calorimetry data also suggest a decrease in the interface energies. A thermodynamic analysis showed that the observed surface energy decrease is responsible for an increase in the stability of solid solutions in the nanophase regime. Although a miscibility gap is expected in this system from bulk phase diagrams, the surface energy contribution modifies the bulk trend and promotes extensive solid solutions when the surface area is above a critical value dependent on the surface energy and the bulk enthalpy of mixing. 相似文献