20 research outputs found
The Family Name as Socio-Cultural Feature and Genetic Metaphor: From Concepts to Methods
A recent workshop entitled The Family Name as Socio-Cultural Feature and Genetic Metaphor: From Concepts to Methods was held in Paris in December 2010, sponsored by the French National Centre for Scientific Research (CNRS) and by the journal Human Biology. This workshop was intended to foster a debate on questions related to the family names and to compare different multidisciplinary approaches involving geneticists, historians, geographers, sociologists and social anthropologists. This collective paper presents a collection of selected communications
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Effects of nitrogen and sulfur fertilization on free amino acids, sugars, and acrylamide-forming potential in potato
Nitrogen (N) fertilizer is used routinely in potato (Solanum tuberosum) cultivation to maximize yield. However, it also affects sugar and free amino acid concentrations in potato tubers, and this has potential implications for food quality and safety because free amino acids and reducing sugars participate in the Maillard reaction during high-temperature cooking and processing. This results in the formation of color, aroma, and flavor compounds, but also some undesirable contaminants, including acrylamide, which forms when the amino acid that participates in the final stages of the reaction is asparagine. Another mineral, sulfur (S), also has profound effects on tuber composition. In this study, 13 varieties of potato were grown in a field trial in 2010 and treated with different combinations of N and S. Potatoes were analyzed immediately after harvest to show the effect of N and S fertilization on concentrations of free asparagine, other free amino acids, sugars, and acrylamide-forming potential. The study showed that N application can affect acrylamide-forming potential in potatoes but that the effect is type- (French fry, chipping, and boiling) and variety-dependent, with most varieties showing an increase in acrylamide formation in response to increased N but two showing a decrease. S application reduced glucose concentrations and mitigated the effect of high N application on the acrylamide-forming potential of some of the French fry-type potatoes
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The DWPF product composition control system at Savannah River: Statistical process control algorithm
The DWPF Process batch-blends aqueous radwaste (PHA) with solid radwaste (Sludge) in a waste receipt vessel (the SRAT). The resulting SRAT-Batch is transferred to the next process vessel (the SME) and there blended with ground glass (Frit) to produce a batch of feed slurry. The SME-Batch is passed to a subsequent hold tank (the MFT) which feeds a Melter continuously. The Melter produces a molten glass wasteform which is poured into stainless steel canisters for cooling and, ultimately, shipment to and storage in a geologic Repository. The Repository will require that the glass wasteform be resistant to leaching by any underground water that might contact it. In addition, there are processing constraints on Viscosity and Liquidus Temperature of the melt. The Product Composition Control System (PCCS) is the system intended to ensure that the melt will be Processible and that the glass wasteform will be Acceptable. Within the PCCS, the SPC Algorithm is the device which guides control of the DWPF process. The SPC Algorithm is needed to control the multivariate DWPF process in the face of uncertainties (variances and covariances) which arise from this process and its supply, sampling, modeling, and measurement systems
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Growth of IGSC cracks in Type 304 stainless steel at 100 degrees C in an aqueous environment
Intergranular stress corrosion (IGSC) cracking has been observed in the primary coolant system of the Savannah River Site Reactors. There have been several cases during the over one hundred reactor-years of plant operating experience when IGSC cracks have grown through-wall and minor leaks have occurred. Approximately 7% of the heat affected zones of pipe-to-pipe butt welds show indications of IGSC cracking during ultrasonic testing (UT). Other piping and component areas, sensitized by flame washing or hot forming, have also developed IGSC cracks. The entire system was fabricated in the 1950's from Type 304 stainless steel. All joining was by the metal inert gas welding process. IGSC crack growth rates have been measured on compact tension specimens under controlled environmental conditions that encompass the observed conditions in the SRS reactor primary coolant systems. Growth rates were measured extending from less than 10{sup {minus}9} to approximately 10{sup {minus}5} millimeter per second. These growth rates bound the growth rates that have been inferred from a statistical analysis of UT indications. The UT data were collected since 1984 from weld heat affected zones in pipe-to-pipe butt welds in the SRS reactor primary coolant piping. Chloride and sulfate anions, dissolved oxygen, and peroxide have been identified as the water impurities that influence IGSC cracking in the SRS reactor primary coolant systems. A quantitative relationship has been established for susceptibility to IGSC cracking in terms of concentrations of these impurities and temperature. The heavy water reactor moderator and coolant is acidified with nitric acid to a pH of 4.7 to minimize corrosion of the aluminum cladding on the fuel elements
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Control of DWPF melter feed composition
The Defense Waste Processing Facility will be used to immobilize Savannah River Site high-level waste into a stable borosilicate glass for disposal in a geologic repository. Proper control of the melter feed composition in this facility is essential to the production of glass which meets product durability constraints dictated by repository regulations and facility processing constraints dictated by melter design. A technique has been developed which utilizes glass property models to determine acceptable processing regions based on the multiple constraints imposed on the glass product and to display these regions graphically. This system along with the batch simulation of the process is being used to form the basis for the statistical process control system for the facility
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Control of DWPF melter feed composition
The Defense Waste Processing Facility will be used to immobilize Savannah River Site high-level waste into a stable borosilicate glass for disposal in a geologic repository. Proper control of the melter feed composition in this facility is essential to the production of glass which meets product durability constraints dictated by repository regulations and facility processing constraints dictated by melter design. A technique has been developed which utilizes glass property models to determine acceptable processing regions based on the multiple constraints imposed on the glass product and to display these regions graphically. This system along with the batch simulation of the process is being used to form the basis for the statistical process control system for the facility
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Statistical analysis of the DWPF prototypic sampler
The DWPF process will be controlled using assay measurements on samples of feed slurry. These slurries are radioactive, and thus will be sampled remotely. A Hydraguard{trademark} pump-driven sampler system will be used as the remote sampling device. A prototype Hydraguard{trademark} sampler has been studied in a full-scale mock-up of a DWPF process vessel. Two issues were of dominant interest: (1) what accuracy and precision can be provided by such a pump-driven sampler in the face of the slurry rheology; and, if the Hydraguard{trademark} sample accurately represents the slurry in its local area, (2) is the slurry homogeneous enough throughout for it to represent the entire vessel? To determine Hydraguard{trademark} Accuracy, a Grab Sampler of simpler mechanism was used as reference. This (Low) Grab Sampler was located as near to the intake port of the Hydraguard{trademark} as could be arranged. To determine Homogeneity, a second (High) Grab Sampler was located above the first. The data necessary to these determinations comes from the measurement system, so its important variables also affect the results. Thus, the design of the test involved not just Sampling variables, but also some of the Measurement variables as well. However, the main concern was the Sampler and not the Measurement System, so the test design included only such measurement variables as could not be circumvented (Vials, Dissolution Method, and Aliquoting). The test was executed by, or under the direct oversight of, expert technologists. It thus did not explore the many important particulars of ``routine`` plant operations (such as Remote Sample Preparation or Laboratory Shift Operation)
Acrylamide: new European risk management measures and prospects for reducing the acrylamide-forming potential of wheat
Acrylamide (C3H5NO) is a processing contaminant formed from free asparagine and reducing sugars during high-temperature cooking and processing. It is a Group 2A carcinogen, and the European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain (CONTAM Panel) has expressed concern for the potential tumor-inducing effects of dietary exposure. Potato, coffee, and cereal products are the major contributors to dietary acrylamide intake. The European Commission recently introduced strengthened risk management regulations for acrylamide in food, including compulsory mitigation measures and new benchmark levels. Measures adopted to reduce acrylamide formation in potato chips in Europe resulted in a 53% decrease from 2002 to 2011. However, since 2011 there has been a leveling off, suggesting that the easy gains have already been made. Acrylamide levels in chips are influenced by seasonal and geographical factors, making regulatory compliance more difficult. In cereals, acrylamide formation is determined by free asparagine concentration, and this differs substantially between varieties. We would support the inclusion of information on grain asparagine concentration in variety descriptions. However, crop management, including ensuring good disease control and sulfur sufficiency, is also important. A key enzyme in asparagine synthesis is asparagine synthetase. Wheat has four asparagine synthetase genes, TaASN1–4. Gene expression and biochemical data have identified TaASN2 as a prime target for genetic interventions to reduce wheat’s acrylamide-forming potential
Reducing the acrylamide-forming potential of crop plants
Acrylamide is a food processing contaminant formed from free asparagine and reducing sugars during high-temperature cooking and processing. It is a Group 2A carcinogen, and EFSA’s CONTAM Panel has expressed concern for the potential tumour-inducing effects of dietary exposure. Fried, baked, roasted and toasted potato, coffee and cereal products are the major contributors to dietary acrylamide intake. The European Commission has recently introduced strengthened risk management regulations for acrylamide in food, including compulsory mitigation measures and new Benchmark Levels. Steps taken by manufacturers to reduce acrylamide formation in potato chips in Europe resulted in a 53 % decrease from 2002 to 2011. However, since 2011 there has been a levelling off, suggesting that the easy gains have already been made and further large reductions are unlikely. The acrylamide-forming potential of potatoes is influenced by seasonal and geographical factors, making regulatory compliance for potato products more difficult. In cereals, acrylamide formation is determined by free asparagine concentration: this differs substantially between varieties but is also very responsive to environmental factors and crop management. Ensuring good disease control and sulfur sufficiency are particularly important. The relationship between precursor concentration and acrylamide formation is more complex in potato, with the concentration of reducing sugars the more important parameter in most datasets but free asparagine concentration contributing to the variance. Storage is a key issue for potatoes due to the phenomena of cold and senescent sweetening. Investigations into the genetic control of acrylamide formation in wheat have focussed on asparagine metabolism, in particular asparagine synthetase, while biotech potatoes with reduced expression of asparagine synthetase and vacuolar invertase are already on the market in the USA