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reference standards

Shelley HuaLei Zhang, Stephan E Maier, Lawrence P Panych
PURPOSE: Magnetic resonance spectroscopic imaging (MRSI), under low-spatial resolution settings, often suffers signal contamination from neighboring voxels due to ringing artifacts. Spatial localization can be improved by constraining the point-spread-function (PSF). Here the effectiveness of the two-dimensional PSF-Choice technique in providing improved spatial localization for MRSI is demonstrated. THEORY AND METHODS: The PSF-Choice technique constrains the PSF to a desired shape by manipulating the weighting of RF excitation pulse throughout phase-encode steps...
March 3, 2018: Journal of Magnetic Resonance
Samuel Mesihää, Ilpo Rasanen, Ilkka Ojanperä
Gas chromatography (GC) hyphenated with nitrogen chemiluminescence detection (NCD) and quadrupole time-of-flight mass spectrometry (QTOFMS) was applied for the first time to the quantitative analysis of new psychoactive substances (NPS) in urine, based on the N-equimolar response of NCD. A method was developed and validated to estimate the concentrations of three metabolites of the common stimulant NPS α-pyrrolidinovalerophenone (α-PVP) in spiked urine samples, simulating an analysis having no authentic reference standards for the metabolites and using the parent drug instead for quantitative calibration...
February 27, 2018: Forensic Science International
Naomi Weintrob, Anita Schachter Davidov, Anat Segev Becker, Galit Israeli, Asaf Oren, Ori Eyal
OBJECTIVE: The total cortisol (TC) response may be measured during the glucagon stimulation test (GST) for growth hormone (GH) reserve in order to assess the integrity of the hypothalamic-pituitary-adrenal (HPA) axis. Measurements of TC are unreliable in conditions of albumin and cortisol-binding globulin (CBG) alterations (e.g., hypoproteinemia or CBG deficiency). We aimed to measure the serum free cortisol (sFC) response to the GST in children and adolescents and determine whether it could predict the GH response to glucagon stimulation...
March 2018: Endocrine Practice
Nora Stünkel-Grees, Jens Clausen, Alexander Wünsch
Outpatient Psychotherapy for Children and Adolescents with Intellectual Disability The psychiatric morbidity risk for people with intellectual disability is considerably increased. Psychotherapy is considered as one possible treatment. Among experts the caresituation is described as substantial insufficient. This study investigated the perspective of psychotherapists for children and adolescents in the German state North Rhine-Westphalia regarding the care situation of outpatient psychotherapy for children and adolescents with intellectual disability...
March 2018: Praxis der Kinderpsychologie und Kinderpsychiatrie
Philip Gc Chan, Gerard S Goh
PURPOSE: The AngioJet Hemolytic Thrombectomy Device "AngioJet" (Boston Scientific, Malborough, MA, USA) is a rheolytic thrombectomy device that can be used in the treatment of hemodialysis arteriovenous fistula and graft thrombosis. We aim to appraise the current evidence on AngioJet thrombectomy in hemodialysis vascular access thrombosis, and to determine its safety, including complications and efficacy. MATERIALS AND METHODS: An electronic literature search was performed on the MEDLINE and Embase databases...
March 1, 2018: Journal of Vascular Access
Ruchita Dixit, Sowmya Nettem, Simerjit S Madan, Htoo Htoo Kyaw Soe, Adinegara Bl Abas, Leah D Vance, Patrick J Stover
BACKGROUND: Sickle cell disease (SCD) is a group of disorders that affects haemoglobin, which causes distorted sickle- or crescent-shaped red blood cells. It is characterized by anaemia, increased susceptibility to infections and episodes of pain. The disease is acquired by inheriting abnormal genes from both parents, the combination giving rise to different forms of the disease. Due to increased erythropoiesis in people with SCD, it is hypothesized that they are at an increased risk for folate deficiency...
March 16, 2018: Cochrane Database of Systematic Reviews
Mattia Bonzi, Giulia Cernuschi, Monica Solbiati, Giuliano Giusti, Nicola Montano, Elisa Ceriani
Infective endocarditis (IE) is a serious and potentially life-threatening disease, and accurate diagnosis is essential. We performed a systematic review and meta-analysis to assess the diagnostic accuracy of transthoracic echocardiography (TTE), with transesophageal echocardiography (TEE) as the reference standard, in patients with suspected IE of the native valves. We performed a systematic search in MEDLINE, EMBASE and Cochrane Library searching for studies that enrolled adult patients with suspected native valves IE where data about both TTE and TEE could be extracted...
March 15, 2018: Internal and Emergency Medicine
Sunao Mizumura, Kazuhiro Nishikawa, Akihiro Murata, Kosei Yoshimura, Nobutomo Ishii, Tadashi Kokubo, Miyako Morooka, Akiko Kajiyama, Atsuro Terahara
OBJECTIVE: In Japan, the Southampton method for dopamine transporter (DAT) SPECT is widely used to quantitatively evaluate striatal radioactivity. The specific binding ratio (SBR) is the ratio of specific to non-specific binding observed after placing pentagonal striatal voxels of interest (VOIs) as references. Although the method can reduce the partial volume effect, the SBR may fluctuate due to the presence of low-count areas of cerebrospinal fluid (CSF), caused by brain atrophy, in the striatal VOIs...
March 15, 2018: Annals of Nuclear Medicine
Bernd Zimmer, Hiba Sino
PURPOSE: The objective of this investigation was to develop equations to describe the geometric relations among "targeted incisor inclinations" (tU1, tL1) accommodating different cephalometric norms (Ricketts, Bergen, etc.) with the "expected inclinations" (eU1, eL1), as they can be generated by bracket torque values according to Andrews, Roth, Ricketts, and MBT. METHODS: In its key parts, the present study is a theoretical work in which structural relationships are described using standard mathematical and geometric methodologies...
March 15, 2018: Journal of Orofacial Orthopedics, Fortschritte der Kieferorthopädie
Juan A Santana, Nahyr A Lopez-Dauphin, Peter Beiersdorfer
Level energies are reported for Si V, Si VI, Si VII, Si VIII, Si IX, Si X, Si XI and Si XII. The energies have been calculated with the relativistic Multi-Reference Møller-Plesset Perturbation Theory method and include valence and K-vacancy states with nl up to 5 f . The accuracy of the calculated level energies is established by comparison with the recommended data listed in the National Institute of Standards and Technology (NIST) on-line database. The average deviation of valence level energies ranges from 0...
2018: Astrophysical Journal. Supplement Series
Cary Presser, Ashot Nazarian, Amit Millo
Thermochemical characteristics were determined for several National Institute of Standards and Technology standard-reference-material petroleum and biodiesel fuels, using a novel laser-heating calorimetry technique. Measurements focused on the sample thermal behavior, specific heat release rate, and total specific heat release. The experimental apparatus consists of a copper sphere-shaped reactor mounted within a chamber, along with laser-beam-steering optical components, gas-supply manifold, and a computer-controlled data-acquisition system...
February 2018: Fuel
Diana Schoeppler, Hans-Ulrich Schnitzler, Annette Denzinger
Bats of the Rhinolophidae and Hipposideridae families, and Pteronotus parnellii, compensate for Doppler shifts generated by their own flight movement. They adjust their call frequency such that the frequency of echoes coming from ahead fall in a specialized frequency range of the hearing system, the auditory fovea, to evaluate amplitude and frequency modulations in echoes from fluttering prey. Some studies in hipposiderids have suggested a less sophisticated or incomplete Doppler shift compensation. To investigate the precision of Doppler shift compensation in Hipposideros armiger, we recorded the echolocation and flight behaviour of bats flying to a grid, reconstructed the flight path, measured the flight speed, calculated the echo frequency, and compared it with the resting frequency prior to each flight...
March 15, 2018: Scientific Reports
Helena S Gouveia, Sílvia O Lopes, Ana Luísa Faria
Tumour lysis syndrome (TLS) is a rare oncological emergency in solid tumours. Because it is associated with bad short-term prognosis, early recognition and treatment are mandatory. This case refers to a middle-aged woman who presented with stage IV colon cancer, with massive hepatic involvement. After three cycles of first-line FOLFOX (folinic acid, 5-fluorouracil and oxaliplatin), she developed acute kidney injury and hyperkalaemia that did not respond to standard measures. High suspicion of TLS prompted further corroborating investigations and early intensive care unit admission...
March 15, 2018: BMJ Case Reports
Meryem Mniouil, Hajiba Fellah, Fatima Amarir, Abderrahim Sadak, Abdeslam Et-Touys, Youssef Bakri, Aziza Moustachi, Fatima Zahraa Tassou, Mostapha Hida, Mohamed Lyagoubi, El Bachir Adlaoui, Mohamed Rhajaoui, Faiza Sebti
A rapid, sensitive and specific tool for detection of Leishmania infantum infection in Humans would be highly desirable, because it would allow control interventions in endemic areas of visceral leishmaniasis. This study was carried out at the Reference National Laboratory of Leishmaniasis (RNLL) in National Institute of Hygiene (NIH) Morocco, in order to evaluate the diagnostic potential of immunochromatographic dipstick test (ICT) rk39 in Moroccan suspected VL patients. A total of 49 admitted patients with strong clinical suspicion of VL and 40 healthy controls were investigated for the performance of the ICT rk39...
March 12, 2018: Acta Tropica
Leontine Mulder, Renate van der Molen, Carin Koelman, Ester van Leeuwen, Anja Roos, Jan Damoiseaux
ISO 15189:2012 requires validation of methods used in the medical laboratory, and lists a series of performance parameters for consideration to include. Although these performance parameters are feasible for clinical chemistry analytes, application in the validation of autoimmunity tests is a challenge. Lack of gold standards or reference methods in combination with the scarcity of well-defined diagnostic samples of patients with rare diseases make validation of new assays difficult. The present manuscript describes the initiative of Dutch medical immunology laboratory specialists to combine efforts and perform multi-center validation studies of new assays in the field of autoimmunity...
March 12, 2018: Autoimmunity Reviews
Melissa L Kirkwood, Gary M Arbique, Jeffrey B Guild, Katie Zeng, Yin Xi, John Rectenwald, Jon A Anderson, Carlos Timaran
OBJECTIVE: Radiation to the interventionalist's brain during fluoroscopically guided interventions (FGIs) may increase the incidence of cerebral neoplasms. Lead equivalent surgical caps claim to reduce radiation brain doses by 50% to 95%. We sought to determine the efficacy of the RADPAD (Worldwide Innovations & Technologies, Lenexa, Kan) No Brainer surgical cap (0.06 mm lead equivalent at 90 kVp) in reducing radiation dose to the surgeon's and trainee's head during FGIs and to a phantom to determine relative brain dose reductions...
March 12, 2018: Journal of Vascular Surgery
Sean Robison, Gauri Rani Karur, Rachel M Wald, Paaladinesh Thavendiranathan, Andrew M Crean, Kate Hanneman
BACKGROUND: Calculation of cardiovascular magnetic resonance (CMR) extracellular volume (ECV) requires input of hematocrit, which may not be readily available. The purpose of this study was to evaluate the diagnostic accuracy of ECV calculated using various noninvasive measures of hematocrit compared to ECV calculated with input of laboratory hematocrit as the reference standard. METHODS: One hundred twenty three subjects (47.7 ± 14.1 years; 42% male) were prospectively recruited for CMR T1 mapping between August 2016 and April 2017...
March 15, 2018: Journal of Cardiovascular Magnetic Resonance
Goran Abdula, Jannike Nickander, Peder Sörensson, Magnus Lundin, Peter Kellman, Andreas Sigfridsson, Martin Ugander
OBJECTIVES: Late gadolinium enhancement (LGE) is the in vivo reference standard for assessing focal myocardial fibrosis. Post-contrast T1-mapping by Modified Look-Locker Inversion recovery (MOLLI) can be used to generate synthetic late gadolinium enhancement (SynLGE) images with an image contrast similar to conventional LGE images. We hypothesized that SynLGE has an accuracy that approaches conventional LGE for diagnosing focal myocardial fibrosis. METHODS: Consecutive patients (n = 109, mean ± SD age 50 ± 16 years, 63% male) referred for clinical cardiac magnetic resonance imaging underwent LGE and post-contrast MOLLI starting 10-15 and 20-25 minutes post contrast, respectively...
March 16, 2018: Scandinavian Cardiovascular Journal: SCJ
Carol Kelly, James D Chalmers, Iain Crossingham, Nicola Relph, Lambert M Felix, David J Evans, Stephen J Milan, Sally Spencer
BACKGROUND: Bronchiectasis is a chronic respiratory disease characterised by abnormal and irreversible dilatation and distortion of the smaller airways. Bacterial colonisation of the damaged airways leads to chronic cough and sputum production, often with breathlessness and further structural damage to the airways. Long-term macrolide antibiotic therapy may suppress bacterial infection and reduce inflammation, leading to fewer exacerbations, fewer symptoms, improved lung function, and improved quality of life...
March 15, 2018: Cochrane Database of Systematic Reviews
Cherian K Kandathil, Emily A Spataro, Katri Laimi, Sami P Moubayed, Sam P Most, Mikhail Saltychev
Importance: While functional rhinoplasty has been broadly studied, to our knowledge no systematic review and meta-analysis of lateral wall repair has been done previously. Objective: To evaluate the effectiveness of repair of the lateral nasal wall in adult patients with nasal airway obstruction. Data Sources: Medline, Embase, Cinahl, Central, Scopus, and Web of Science databases and reference lists were searched for clinical and observational studies...
March 15, 2018: JAMA Facial Plastic Surgery
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