White Powder (white + powder)

Distribution by Scientific Domains


Selected Abstracts


High performance liquid chromatography (HPLC) in the investigation of gout in palaeopathology

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 2 2010
D. Swinson
Abstract Gout is a disease caused by the abnormal accumulation of uric acid in the body, which can result in sodium urate crystals forming tophi at joints, with associated erosion of bone and cartilage. Only two examples of tophi have been reported from archaeological individuals, and the diagnosis of gout based on dry bone manifestations can be difficult. This paper presents preliminary results of a new technique to aid the diagnosis of gout in palaeopathology, namely high performance liquid chromatography (HPLC). Five archaeological skeletons with suspected gout (diagnosed using visual and radiological analysis) and three controls were analysed. Two of the gouty individuals had a white powder in their erosive lesions. HPLC showed the presence of uric acid in bone in four of the five individuals with evidence of gouty arthritis and was negative for uric acid in bone from the three controls. The white powder was also positive for uric acid. With reliance on the presence of articular erosions, cases of gout will be missed in archaeological human bone. HPLC measurement of uric acid could prove useful in the differential diagnosis of erosive arthropathy in archaeology. It may also be useful in identifying individuals with an increased body pool of uric acid, linked to conditions included in the term ,metabolic syndrome'. As a result, HPLC uric acid measurement also has the potential to provide additional information on health and lifestyle in past communities. Copyright © 2008 John Wiley & Sons, Ltd. [source]


An Epidemic of Illicit Fentanyl Deaths in Cook County, Illinois: September 2005 through April 2007

JOURNAL OF FORENSIC SCIENCES, Issue 2 2008
J. Scott Denton M.D.
Abstract:, Between September 2005 and April 2007, 350 fentanyl intoxication deaths were investigated and certified by the Cook County Medical Examiners Office. Investigations revealed that the majority of these fatalities were by intravenous injection of a white powder followed by a rapid collapse. The fentanyl was clandestinely produced in a lab in Toluca, Mexico and sold by the Mickey Cobra street gang. The term "Drop Dead" was coined for this "tainted heroin." Postmortem samples were screened by ELISA and confirmed by standard GC-MS methods. Fentanyl fatalities peaked at 47 per month in May and June 2006. Fifty-two percent were single fentanyl intoxications, with the remainder accompanied by either cocaine, morphine from heroin, or alcohol. This epidemic stressed the limited resources of the toxicology laboratory and autopsy service of the Medical Examiners Office. The clandestine lab was terminated, distributing gang members and leaders arrested, and the epidemic ceased in April 2007. [source]


CdBiO2Cl: synthesis and powder structure solution

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2001
Sergei D. Kirik
The title compound, cadmium bismuth dioxide chloride, CdBiO2Cl, was obtained as a white powder by reaction of solid BiOCl with CdO at 973,K. Ab initio crystal structure determination was carried out using X-ray powder diffraction techniques, including direct methods for atom location and Rietveld fitting for the final refinement. Being monoclinic, the crystal structure can be related to tetragonal Sillen layered phases. The main structural elements present are CdBiO2+ pleated metal,oxy­gen layers alternating with Cl layers along the c axis, whereas along the b axis, all atoms are on mirror planes. The formation of a strong Cd,Cl bond draws the layers together, causing layer deformation and a monoclinic distortion in the layer arrangement. [source]


Radical copolymerization of vinylidene fluoride with 1-bromo-2,2-difluoroethylene

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2010
G. K. Kostov
Abstract The radical copolymerization of vinylidene fluoride (VDF) and 1-bromo-2,2-difluoroethylene (BDFE) in 1,1,1,3,3-pentafluorobutane solution at different monomer molar ratios (ranging from 96/4 to 25/75 mol %) and initiated by tert -butylperoxypivalate (TBPPI, mainly) is presented. Poly(VDF- co -BDFE) copolymers of various aspects (from white powders to yellow viscous liquids) were produced depending on the copolymer compositions. The microstructures of the obtained copolymers were characterized by 19F and 1H NMR spectroscopy and by elementary analysis and these techniques enabled one to assess the contents of both comonomers in the produced copolymers. VDF was shown to be more incorporated in the copolymer than BDFE. From the extended Kelen and Tudos method, the kinetics of the radical copolymerization led to the determination of the reactivity ratios, ri, of both comonomers (rVDF = 1.20 ± 0.50 and rBDFE = 0.40 ± 0.15 at 75 °C) showing that VDF is more reactive than BDFE. Alfrey-Price's Q and e values of BDFE monomer were calculated to be 0.009 (from QVDF = 0.008) or 0.019 (from QVDF = 0.015) and +1.22 (vs. eVDF = 0.40) or +1.37 (vs. eVDF = 0.50), respectively, indicating that BDFE is an electron-accepting monomer. Statistic cooligomers were produced with molar masses ranging from 1,800 to 5,500 g/mol (assessed by GPC with polystyrene standards). A further evidence of the successful copolymerization was shown by the selective reduction of bromine atoms in poly(VDF- co -BDFE) cooligomers that led to analog PVDF. The thermal properties of the poly(VDF- co -BDFE) cooligomers were also determined and those containing a high VDF amount exhibited a high thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3964,3976, 2010. [source]


Block copolymers of poly(ethylene oxide) and poly(vinyl alcohol) synthesized by the RAFT methodology

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2009
Yin-Yin Tong
Abstract A methodology for the synthesis of well-defined poly(ethylene oxide)- block -poly(vinyl alcohol) (PEO- b -PVA) and PVA- b -PEO- b -PVA polymers was reported. Novel xanthate end-functionalized PEOs were synthesized by a series of end-group transformations. They were then used to mediate the reversible addition,fragmentation chain transfer polymerization of vinyl acetate to obtain well-defined poly(ethylene oxide)- b -poly(vinyl acetate) (PEO- b -PVAc) and PVAc- b -PEO- b -PVAc. When these block copolymers were directly hydrolyzed in methanol solution of sodium hydroxide, polymers with brown color were obtained, which was due to the formation of conjugated unsaturated aldehyde structures. To circumvent these side reactions, the xanthate groups were removed by adding a primary amine before hydrolysis and the products thus obtained were white powders. The polymers were characterized by gel permeation chromatography, 1H NMR spectroscopy and FT-IR. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1901,1910, 2009 [source]


Synthesis and polymerization reactions of cyclic imino ethers.

POLYMER ENGINEERING & SCIENCE, Issue 8 2007

To study the effect of nonequal reactivity of B units in ABx monomers, two novel monomers for synthesis of hyperbranched polymers of the polyaddition type, namely 2-(2,5-dihydroxyphenyl)-2-oxazoline (2a) and 2-(2,4-dihydroxyphenyl)-2-oxazoline (2b) were prepared and characterized. Both monomers have one free phenolic group and one hydrogen-bonded phenolic group with the difference in chemical shift more than 2 ppm. Both monomers undergo thermally initiated polymerization in bulk and in solution at the temperature 220°C during 1 h in bulk and 24 h in solution of 1-chloronaphthalene. Products are white powders with degree of polymerization 17 and 13 for the respective polymer 3a and 3b. The degree of branching is 0.37 and 0.3 for the respective polymer. The structure of polymers is in agreement with the structure, which was expected from the structure of monomers and consists of linear, dendritic, and terminal units. POLYM. ENG. SCI., 47:1272,1280, 2007. © 2007 Society of Plastics Engineers [source]