396 research outputs found
Transcendental Numbers
The numbers e and π are transcendental numbers, meaning each of them are not the root of any polynomial with rational coefficients. We prove that e and π are transcendental numbers. The original proofs use the Fundamental Theorem of Symmetric Polynomials and Stirling’s Formula, which we develop and prove. Since π is not algebraic, neither is √π, which answers the ancient question of whether one can square a circle. The proof that π is transcendental is a beautiful example of how higher level mathematics can be used to answer ancient questions
Exploratory Molten Flux Crystal Growth of Complex Uranium Oxides
While the use of nuclear technology has proven useful for energy generation and for military use, the proper disposal and storage of the resulting nuclear waste requires serious attention to ensure radioactive species are indefinitely sequestered to protect the biosphere. There are several classifications of nuclear waste such as spent nuclear fuel (from industrial power plants), low level waste (slightly contaminated trash), and high level waste (HLW) which is in the form of a sludge, precipitated salt, or liquid. Each of these requires a different approach to processing and storage. Of these, HLW requires the most attention because it is the most expensive, highest risk, and will take longest to process and store. While the current method of incorporating the HLW into a glass is very successful, it is inefficient for a few of the species found in this waste such as Cs, I, and Tc.
The lack of a universal waste storage material not only calls us to further characterize known materials that are good candidates for waste sequestration, but also to discover new materials with potentially better properties than those of existing materials. Crystal growth, in general, is well suited for material discovery as it facilitates the preparation of new complex compositions in the absence of a fully established crystal chemistry and crystals can be efficiently characterized by single crystal X-ray diffraction. This work explores the exploratory flux crystal growth of uranium oxide framework structures and characterizes their structures as well as thermal and ion exchange properties which are useful for preliminary screening of potential wasteforms and discovering structure-property relationships
Experience with the Multi-Year Implementation of an Industrial Control System
In 1990, CERN passed a multi-year purchasing and installation contract for the LEP 200 Cryogenics control system with ABB, one of the world's leading suppliers of integrated Distributed Control Systems (DCS). A financial framework provided over a period of eight years the required supplies. These were called up with so called "Release Orders", taking into account the latest technical developments. The issues and experiences with such a new approach and the resulting control system are described
Zinc absorption in adult humans: the effect of protein sources added to liquid test meals
The influence of different protein sources on Zn absorption was evaluated in healthy adults by radioisotopic labelling of single meals, followed by whole-body retention measurements 14 d after intake. Semi-synthetic liquid diets were used for the evaluation of different animal-protein sources and dephytinized soyabean-protein isolate ( ··01 g phytic acid/kg). Zn absorption was measured in the same subjects from identical test meals containing no added protein. No statistically significant differences were found in the Zn absorption from test meals containing bovine whey, casein or egg albumen when compared with test meals without added protein. Bovine serum albumin (BSA) and soyabean-protein isolate (< ··01 g phytic acid/kg) significantly reduced the mean absorption of Zn from 45-49% (no added protein) to 38·0 (SD 10·9) (BSA, P < ··05) and 33·9 (SD 12·6)% (soyabean-protein isolate < ··01 g phytic acid/kg, P < ··01). These results demonstrate that Zn absorption is inhibited by certain protein sources, such as BSA and dephytinized soyabean-protein isolate, while other proteins have little or no effec
Tryptic phosphopeptides from whole casein. I. Preparation and analysis by fast protein liquid chromatography
Tryptic phosphopeptides were obtained from whole bovine casein by chromatography on the anion exchange resin QAE-Sephadex A 25. Salt gradient elution of the column allowed separation of non-phosphorylated peptides from phosphorylated species. The preparations obtained contained at least seven distinct phosphopeptides of which the following casein fragments were identified: αs1(43-58):2P, αs1(59-79): 5P, αs2(46-70): 4P, β(1-28): 4P, β(2-28): 4P, and β(33-48): 1P. Fast protein liquid chromatography (FPLC) on Mono Q HR 5/5 resin showed that the phosphopeptides were eluted in the same order as from the QAE-Sephadex resin. However, on the analytical column HR 5/5 the fragments αs1(59-79): 5P and β(2-28): 4P, having the same net charge under the conditions of chromatography, co-eluted, whereas they were at least partly separated on the preparative column HR 16/10. Following enzymic dephosphorylation, the peptides eluted at lower salt strength in the gradient. FPLC on Mono Q resin thus permitted dephosphorylation to be monitored and intermediates between the parent species and the fully dephosphorylated peptide to be identifie
Tryptic phosphopeptides from whole casein. II. Physicochemical properties related to the solubilization of calcium
Casein phosphopeptides (GPP) were produced by tryptic hydrolysis of sodium caseinate and further purified by precipitation and chromatography on QAE-Sephadex A-25. Their physico-chemical properties were compared with the properties of an enzymically dephosphorylated equivalent preparation (DPP). Binding of Ca2+ to the peptides was measured using a Ca selective electrode and was found to increase with pH and to show 1/1 stoicheiometry Ca/Porg in CPP at pH 6·5 a.nd 7·6. Klotz plots indicated equivalent binding sites at these two pH values, but some heterogeneity was seen at pH 3·5. In contrast, DPP did not bind significant amounts of Ca2+. CPP effectively inhibited the formation of insoluble calcium phosphates at different Ca/P ratios. The effective CPP concentration was 10 mg/1 and complete stability of calcium phosphate solutions was obtained at about 100 mg/1. This stabilizing effect was dependent on the presence of organic
Cryogenic Facilities at 1.9 K for the Reception of the Superconducting Wires and Cables of the LHC Dipoles Magnets
CERN's LHC project has moved to an implementation phase. The fabrication of 1600 high-field superconducting magnets operating at 1.9 K will require about 6400 km of Nb-Ti cables. A cryogenic test facility has therefore been set up in order, on the one hand, to verify the quality of individual wires and, on the other hand, to control the critical current of the assembled cables. The facility is composed of a helium liquefier, a transfer line, a dewar and pumps. The paper describes the fully automatic operation of this installation and the different test cycles applied to these wires and cables
P719 Determinants of tobacco consumption in the Swiss IBD cohort
Background: Tobacco consumption is an important environmental factor in inflammatory bowel diseases (IBD). Our aim was to identified characteristics associated with smoking in Crohn's disease (CD) and Ulcerative colitis (UC).
Methods: Adult UC and CD patients included in the Swiss IBD cohort study (SIBDCS) from Nov. 2006 to Nov. 2015 were asked about their smoking status. Patients were separated in two groups (active smokers vs. non-smokers). A logistic regression analysis was performed with smoking as main outcome
Differential stress reaction of human colon cells to oleic-acid-stabilized and unstabilized ultrasmall iron oxide nanoparticles.
Therapeutic engineered nanoparticles (NPs), including ultrasmall superparamagnetic iron oxide (USPIO) NPs, may accumulate in the lower digestive tract following ingestion or injection. In order to evaluate the reaction of human colon cells to USPIO NPs, the effects of non-stabilized USPIO NPs (NS-USPIO NPs), oleic-acid-stabilized USPIO NPs (OA-USPIO NPs), and free oleic acid (OA) were compared in human HT29 and CaCo2 colon epithelial cancer cells. First the biophysical characteristics of NS-USPIO NPs and OA-USPIO NPs in water, in cell culture medium supplemented with fetal calf serum, and in cell culture medium preconditioned by HT29 and CaCo₂ cells were determined. Then, stress responses of the cells were evaluated following exposure to NS-USPIO NPs, OA-USPIO NPs, and free OA. No modification of the cytoskeletal actin network was observed. Cell response to stress, including markers of apoptosis and DNA repair, oxidative stress and degradative/autophagic stress, induction of heat shock protein, or lipid metabolism was determined in cells exposed to the two NPs. Induction of an autophagic response was observed in the two cell lines for both NPs but not free OA, while the other stress responses were cell- and NP-specific. The formation of lipid vacuoles/droplets was demonstrated in HT29 and CaCo₂ cells exposed to OA-USPIO NPs but not to NS-USPIO NPs, and to a much lower level in cells exposed to equimolar concentrations of free OA. Therefore, the induction of lipid vacuoles in colon cells exposed to OA utilized as a stabilizer for USPIO NPs is higly amplified compared to free OA, and is not observed in the absence of this lipid in NS-USPIO NPs
Case Report: Don’t chew the fufu: a case report of suspected drug body stuffing
Background: Intrabody concealment of illicit substances is a common practice in the trafficking chain. Body packing is a technique used in drug trafficking that consists of deliberately ingesting many drug pellets. Body stuffing consists of precipitously swallowing packets of substances, which are smaller and more fragile than body-packing pellets, for concealment from law-enforcement officers in anticipation of impending search or arrest. Therefore, body stuffing is particularly dangerous due to the rupture risk of the loosely wrapped drug packets, which could lead to substance intoxication or even death. Case presentation: This article reports the case of a young man who was taken by law enforcement authorities to our Emergency Department for investigation of suspected body stuffing. Although the patient denied the facts, the initial reading of the computed tomography (CT) scan confirmed the presence of multiple images compatible with drug pellets, which were mostly in the stomach. The pellet findings were more consistent with body packing than body stuffing as initially suspected by the police. However, upon admission to our secured inpatient ward for clinical surveillance of pellet evacuation, the patient denied again having ingested such pellets, and declared that he only ate ‘fufu’. Fufu is a traditional food of central and western Africa consisting of a starchy preparation compacted by hand into small balls. Fufu balls are usually swallowed without chewing to allow a sensation of stomach fullness throughout the day. Considering the fufu intake history, a careful reassessment of the imaging confirmed the presence of food content. Conclusions: This case study offers an example of suspected intrabody concealment of illicit substances, which turned out to be false positive due to fufu. It illustrates the importance of a history of food intake that could bias the interpretation of CT scan images.</ns3:p
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