keyword
MENU ▼
Read by QxMD icon Read
search

reference materials

keyword
https://www.readbyqxmd.com/read/28917745/chlorine-determination-via-mgcl-molecule-in-environmental-samples-using-high-resolution-continuum-source-graphite-furnace-molecular-absorption-spectrometry
#1
Rina Lourena da S Medeiros, Sidnei Oliveira Souza, Rennan Geovanny Oliveira Araújo, Djalma Ribeiro da Silva, Tatiane de A Maranhão
This paper describes a method development for chlorine determination through the formation of MgCl molecule, applied for the first time for Cl quantification, by high resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) in environmental samples. Pyrolysis and vaporization temperatures were optimized as well as the use of chemical modifier. Determinations were carried out at the wavelength of 377.010 and the compromise conditions of the graphite furnace temperature program were 500°C and 2500°C for pyrolysis and vaporization, respectively, using 10µg of chemical modifier Pd...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917739/determination-of-fluorine-in-copper-concentrate-via-high-resolution-graphite-furnace-molecular-absorption-spectrometry-and-direct-solid-sample-analysis-comparison-of-three-target-molecules
#2
Heloisa R Cadorim, Jefferson S de Gois, Aline R Borges, Maria Goreti R Vale, Bernhard Welz, Heike Gleisner, Christina Ott
The chemical composition of complex inorganic materials, such as copper concentrate, may influence the economics of their further processing because most smelters, and particularly the producers of high-purity electrolyte copper, have strict limitations for the permissible concentration of impurities. These components might be harmful to the quality of the products, impair the production process and be hazardous to the environment. The goal of the present work is the development of a method for the determination of fluorine in copper concentrate using high-resolution graphite furnace molecular absorption spectrometry and direct solid sample analysis...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917261/development-of-standard-reference-material-srm-2973-vitamin-d-metabolites-in-frozen-human-serum-high-level
#3
Susan S-C Tai, Michael A Nelson, Mary Bedner, Brian E Lang, Karen W Phinney, Lane C Sander, James H Yen, Joseph M Betz, Christopher T Sempos, Stephen A Wise
The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health Office of Dietary Supplements and the Vitamin D Standardization Program, has recently issued a new serum-matrix Standard Reference Material (SRM): 2973 Vitamin D Metabolites in Frozen Human Serum (High Level). SRM 2973 was designed to provide a serum material with a total 25-hydroxyvitamin D [25(OH)D] concentration near 100 nmol/L to complement the existing serum-based SRMs with values assigned for total 25(OH)D between 20 and 80 nmol/L...
September 1, 2017: Journal of AOAC International
https://www.readbyqxmd.com/read/28916744/hydrogen-sulphate-based-ionic-liquid-assisted-electro-polymerization-of-pedot-catalyst-material-for-high-efficiency-photoelectrochemical-solar-cells
#4
Buket Bezgin Carbas, Mahir Gulen, Merve Celik Tolu, Savas Sonmezoglu
This work reports the facile, one-step electro-polymerization synthesis of poly (3,4-ethylenedioxythiophene) (PEDOT) using a 1-ethyl-3-methylimidazolium hydrogen sulphate (EMIMHSO4) ionic liquid (IL) and, for the first time its utilization as a counter electrode (CE) in dye-sensitized solar cells (DSSCs). Using the IL doped PEDOT as CE, we effectively improve the solar cell efficiency to as high as 8.52%, the highest efficiency reported in 150 mC/cm(2) charge capacity, an improvement of ~52% over the control device using the bare PEDOT CE (5...
September 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28916101/improved-analytical-techniques-of-sulfur-isotopic-composition-in-nanomole-quantities-by-mc-icp-ms
#5
Tsai-Luen Yu, Bo-Shian Wang, Chuan-Chou Shen, Pei-Ling Wang, Tsanyao Frank Yang, George S Burr, Yue-Gau Chen
We propose an improved method for precise sulfur isotopic measurements by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in conjunction with a membrane desolvation nebulization system. The problems of sulfur loss through the membrane desolvation apparatus are carefully quantified and resolved. The method overcomes low intrinsic sulfur transmission through the instrument, which was initially 1% when operating at a desolvation temperature of 160 °C. Sulfur loss through the membrane desolvation apparatus was resolved by doping with sodium...
October 2, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28915925/biomechanical-analysis-of-the-posterior-bony-column-of-the-lumbar-spine
#6
Jiukun Li, Shuai Huang, Yubo Tang, Xi Wang, Tao Pan
BACKGROUND: Each part of the rear bone structure can become an anchor point for an attachment device. The objective of this study was to evaluate the stiffness and strength of different parts of the rear lumbar bone structure by axial compression damage experiments. METHODS: Five adult male lumbar bone structures from L2 to L5 were exposed. The superior and inferior articular processes, upper and lower edges of the lamina, and upper and lower edges of the spinous process were observed and isolated and then divided into six groups (n = 10)...
September 15, 2017: Journal of Orthopaedic Surgery and Research
https://www.readbyqxmd.com/read/28915871/virtual-patients-in-the-acquisition-of-clinical-reasoning-skills-does-presentation-mode-matter-a-quasi-randomized-controlled-trial
#7
Fabian Schubach, Matthias Goos, Götz Fabry, Werner Vach, Martin Boeker
BACKGROUND: The objective of this study is to compare two different instructional methods in the curricular use of computerized virtual patients in undergraduate medical education. We aim to investigate whether using many short and focused cases - the key feature principle - is more effective for the learning of clinical reasoning skills than using few long and systematic cases. METHODS: We conducted a quasi-randomized, non-blinded, controlled parallel-group intervention trial in a large medical school in Southwestern Germany...
September 15, 2017: BMC Medical Education
https://www.readbyqxmd.com/read/28915519/-e-cigarettes-on-everyone-s-lips-current-representative-data-on-use-among-adolescents-and-adults
#8
Sven Schneider, Tatiana Görig, Laura Schilling, Katharina Diehl
Background International data suggest an increase in e-cigarette use. However, there are still significant deficits in the reporting of its current prevalence. The present study reports representative data on e-cigarette use that make it possible to differentiate users both by the nicotine content of the e-cigarette liquids being used and by their smoking status. Methods and material The underlying data are taken from the National Cancer Aid Monitoring (NCAM). In its first wave, 3000 persons aged between 14 and 45 were interviewed by telephone...
September 15, 2017: Deutsche Medizinische Wochenschrift
https://www.readbyqxmd.com/read/28915102/acceleration-selective-arterial-spin-labeling-mr-angiography-used-to-visualize-distal-cerebral-arteries-and-collateral-vessels-in-moyamoya-disease
#9
Osamu Togao, Akio Hiwatashi, Makoto Obara, Koji Yamashita, Kazufumi Kikuchi, Ryotaro Kamei, Ataru Nishimura, Koichi Arimura, Koji Yoshimoto, Koji Iihara, Marc Van Cauteren, Hiroshi Honda
Purpose To evaluate and compare the performance of acceleration-selective arterial spin labeling (AccASL) magnetic resonance (MR) angiography in the visualization of cerebral arteries and collateral vessels in patients with Moyamoya disease with that of time-of-flight (TOF) MR angiography, with digital subtraction angiography (DSA) as the reference standard. Materials and Methods Thirty-six cerebral hemispheres from 22 patients with Moyamoya disease underwent TOF and AccASL MR angiography and DSA. Qualitative evaluations included imaging of the terminal internal carotid artery (ICA), distal middle cerebral arteries (MCAs), Moyamoya vessels, and leptomeningeal anastomosis (LMA) collaterals with reference to DSA...
September 15, 2017: Radiology
https://www.readbyqxmd.com/read/28914821/biocompatibility-of-titania-nanotube-coatings-enriched-with-silver-nanograins-by-chemical-vapor-deposition
#10
Piotr Piszczek, Żaneta Lewandowska, Aleksandra Radtke, Tomasz Jędrzejewski, Wiesław Kozak, Beata Sadowska, Magdalena Szubka, Ewa Talik, Fabrizio Fiori
Bioactivity investigations of titania nanotube (TNT) coatings enriched with silver nanograins (TNT/Ag) have been carried out. TNT/Ag nanocomposite materials were produced by combining the electrochemical anodization and chemical vapor deposition methods. Fabricated coatings were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The release effect of silver ions from TNT/Ag composites immersed in bodily fluids, has been studied using inductively coupled plasma mass spectrometry (ICP-MS)...
September 15, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28914598/ovarian-cancer-prevalence-in-incidental-simple-adnexal-cysts-initially-identified-in-ct-examinations-of-the-abdomen-and-pelvis
#11
Johannes Boos, Olga R Brook, Jieming Fang, Alexander Brook, Deborah Levine
Purpose To evaluate the rate of malignancy in incidentally detected simple adnexal cysts at computed tomography (CT) to determine if simple-appearing cysts require follow-up. Materials and Methods In this HIPAA-compliant, institutional review board-approved retrospective cohort study, an institutional database was searched for abdominal and pelvic CT studies performed between June 2003 and December 2010 in women reported to have adnexal cysts. Adnexal cyst characterization was determined by prospective report description as well as image review by a research fellow and by a fellowship-trained abdominal radiologist for examinations with disagreement between the original report and the research fellow's assessment...
September 14, 2017: Radiology
https://www.readbyqxmd.com/read/28914372/the-role-of-gut-microbiota-in-the-pathogenesis-of-rheumatic-diseases
#12
Danli Zhong, Chanyuan Wu, Xiaofeng Zeng, Qian Wang
Rheumatic diseases refer to many diseases with a loss of immune self-tolerance, leading to a chronic inflammation, degeneration, or metabolic derangement in multiple organs or tissues. The cause of rheumatic diseases remains to be elucidated, though both environmental and genetic factors are required for the development of rheumatic diseases. Over the past decades, emerging studies suggested that alteration of intestinal microbiota, known as gut dysbiosis, contributed to the occurrence or development of a range of rheumatic diseases, including rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, systemic sclerosis, and Sjogren's syndrome, through profoundly affecting the balance between pro- and anti-inflammatory immune responses...
September 15, 2017: Clinical Rheumatology
https://www.readbyqxmd.com/read/28913812/theory-of-liquid-crystal-elastomers-and-polymer-networks-connection-between-neoclassical-theory-and-differential-geometry
#13
Thanh-Son Nguyen, Jonathan V Selinger
In liquid crystal elastomers and polymer networks, the orientational order of liquid crystals is coupled with elastic distortions of crosslinked polymers. Previous theoretical research has described these materials through two different approaches: a neoclassical theory based on the liquid crystal director and the deformation gradient tensor, and a geometric elasticity theory based on the difference between the actual metric tensor and a reference metric. Here, we connect those two approaches using a formalism based on differential geometry...
September 2017: European Physical Journal. E, Soft Matter
https://www.readbyqxmd.com/read/28913422/ultratransparent-and-stretchable-graphene-electrodes
#14
Nan Liu, Alex Chortos, Ting Lei, Lihua Jin, Taeho Roy Kim, Won-Gyu Bae, Chenxin Zhu, Sihong Wang, Raphael Pfattner, Xiyuan Chen, Robert Sinclair, Zhenan Bao
Two-dimensional materials, such as graphene, are attractive for both conventional semiconductor applications and nascent applications in flexible electronics. However, the high tensile strength of graphene results in fracturing at low strain, making it challenging to take advantage of its extraordinary electronic properties in stretchable electronics. To enable excellent strain-dependent performance of transparent graphene conductors, we created graphene nanoscrolls in between stacked graphene layers, referred to as multilayer graphene/graphene scrolls (MGGs)...
September 2017: Science Advances
https://www.readbyqxmd.com/read/28912414/polish-experience-with-liver-transplantation-and-post-transplant-outcomes-in-children-with-urea-cycle-disorders
#15
Edyta Szymańska, Piotr Kaliciński, Joanna Pawłowska, Sylwia Szymańska, Maciej Pronicki, Marek Stefanowicz, Joanna Teisseyre, Dorota Broniszczak, Dariusz Rokicki
BACKGROUND Liver transplantation (LT) is recommended for various metabolic diseases, including urea cycle disorders (UCDs). The aim of this study was to determine indications and outcomes of LT for UCDs in the tertiary reference Children's Hospital in Warsaw, Poland. MATERIAL AND METHODS Medical charts of children with UCD who underwent LT between 2008 and July 2016 were retrospectively reviewed. The following parameters were analyzed: symptoms at time of diagnosis, age at diagnosis, age at transplantation, graft characteristics and survival, postsurgical complications, and biochemical and laboratory results before and after transplantation...
September 15, 2017: Annals of Transplantation: Quarterly of the Polish Transplantation Society
https://www.readbyqxmd.com/read/28911607/certification-of-caffeine-reference-material-purity-by-ultraviolet-visible-spectrophotometry-and-high-performance-liquid-chromatography-with-diode-array-detection-as-two-independent-analytical-methods
#16
REVIEW
A B Shehata, M S Rizk, E A Rend
Caffeine reference material certified for purity is produced worldwide, but no research work on the details of the certification process has been published in the literature. In this paper, we report the scientific details of the preparation and certification of pure caffeine reference materials. Caffeine was prepared by extraction from roasted and ground coffee by dichloromethane after heating in deionized water mixed with magnesium oxide. The extract was purified, dried, and bottled in dark glass vials. Stratified random selection was applied to select a number of vials for homogeneity and stability studies, which revealed that the prepared reference material is homogeneous and sufficiently stable...
October 2016: Journal of Food and Drug Analysis
https://www.readbyqxmd.com/read/28910324/effect-of-dialyzer-membrane-materials-on-survival-in-chronic-hemodialysis-patients-results-from-the-annual-survey-of-the-japanese-nationwide-dialysis-registry
#17
Masanori Abe, Takayuki Hamano, Atsushi Wada, Shigeru Nakai, Ikuto Masakane
BACKGROUND: Little information is available regarding which type of dialyzer membrane results in good prognosis in patients on chronic hemodialysis. Therefore, we conducted a cohort study from a nationwide registry of hemodialysis patients in Japan to establish the association between different dialyzer membranes and mortality rates. METHODS: We followed 142,412 patients on maintenance hemodialysis (female, 39.1%; mean age, 64.8 ± 12.3 years; median dialysis duration, 7 [4-12] years) for a year from 2008 to 2009...
2017: PloS One
https://www.readbyqxmd.com/read/28910083/inhibiting-mercury-reemission-and-enhancing-magnesia-recovery-by-cobalt-loaded-carbon-nanotubes-in-a-novel-magnesia-desulfurization-process
#18
Lidong Wang, Tieyue Qi, Mengxuan Hu, Shihan Zhang, Peiyao Xu, Dan Qi, Siyu Wu, Huining Xiao
Mercury re-emission because of the reduction of Hg2+ to form Hg0 by sulfite has been becoming a great concern in the desulfurization process. Lowering down the concentrations of Hg2+ and sulfite in the desulfurization slurry can retard the Hg0 formation and thus mitigate the mercury re-emission. To that end, cobalt-based carbon nanotubes (Co-CNTs) were developed for the simultaneous Hg2+ removal and sulfite oxidation in this work. Furthermore, the thermodynamics and kinetics of the Hg2+ adsorption and effect of Hg2+ adsorption on catalytic activity of Co-CNTs were investigated...
September 14, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28904631/do-research-papers-provide-enough-information-on-design-and-material-used-in-ankle-foot-orthoses-for-children-with-cerebral-palsy-a-systematic-review
#19
N Eddison, M Mulholland, N Chockalingam
OBJECTIVES: The purpose of this article is to determine how many of the current peer-reviewed studies of ankle foot or-thoses (AFOs) on children with cerebral palsy (CP) have included adequate details of the design and material of the AFO, to enable the study to be reproduced and outcomes clearly understood. METHODS: A thorough search of studies published in English was conducted in March 2015, with no restriction on dates, within all major databases using relevant phrases...
August 1, 2017: Journal of Children's Orthopaedics
https://www.readbyqxmd.com/read/28904269/the-effectiveness-of-specific-risk-mitigation-techniques-used-in-the-production-and-handling-of-manufactured-nanomaterials-a-systematic-review
#20
Toshihiko Myojo, Tomohisa Nagata, Jos Verbeek
Many kinds of manufactured nanomaterials (MNMs) have been developed and used as basic materials of industrial products, and they may pose health risks for workers in not only developed countries but also in developing countries. Few studies have looked at the evidence for effects of controls that mitigate the risk of exposure to MNMs. Therefore, we systematically searched the literature from the year 2000 to 2015. We included studies that compared the use of an exposure control to the situation without such a technique and those that measured the exposure to MNMs as the outcome...
2017: Journal of UOEH
keyword
keyword
112810
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"