Publications by authors named "William Guthrie"

Importance: The association of guideline-based decision support with the quality of care in patients with non-small cell lung cancer (NSCLC) is not known.

Objective: To evaluate the association of exposure to the National Comprehensive Cancer Center (NCCN) guidelines with guideline-concordant care and patients' decisional conflict.

Design, Setting, And Participants: A nonrandomized clinical trial, conducted at a tertiary care academic institution, enrolled patients from February 23, 2015, to September 28, 2017.

View Article and Find Full Text PDF
Article Synopsis
  • A new standard reference material (SRM 3600) for small-angle X-ray scattering (SAXS) has been developed using glassy carbon to enable accurate intensity calibration.
  • The validation of this SRM has confirmed its reliability within a certified range of 0.008-0.25 Å, making it applicable to various SAXS instruments that utilize transmission measurement geometries.
  • The article also highlights the potential for future certification renewals that may include validation with small-angle neutron scattering (SANS) techniques.
View Article and Find Full Text PDF

A new material has been certified to become Standard Reference Material (SRM) 2806b - Medium Test Dust in Hydraulic Fluid. SRM 2806b consists of trace polydisperse, irregularly shaped mineral dust particles suspended in hydraulic fluid. The certified values of SRM 2806b are the projected area circular-equivalent diameters of the collected dust particles from the hydraulic fluid.

View Article and Find Full Text PDF

In recent years there has been considerable interest in developing photonic temperature sensors such as the Fiber Bragg gratings (FBG) as an alternative to resistance thermometry. In this study we examine the thermal response of FBGs over the temperature range of 233 K to 393 K. We demonstrate, in hermetically sealed dry Argon environment, FBG devices show a quadratic dependence on temperature with expanded uncertainties (k=2) of ≈500 mK.

View Article and Find Full Text PDF

The devices calibrated most frequently by the acoustical measurement services at the National Institute of Standards and Technology (NIST) over the 50-year period from 1963 to 2012 were one-inch condenser microphones of three specific standard types: LS1Pn, LS1Po, and WS1P. Due to its long history of providing calibrations of such microphones to customers, NIST is in a unique position to analyze data concerning the long-term stability of these devices. This long history has enabled NIST to acquire and aggregate a substantial amount of repeat calibration data for a large number of microphones that belong to various other standards and calibration laboratories.

View Article and Find Full Text PDF
Article Synopsis
  • A new radiochemical neutron activation analysis (RNAA) method was developed to measure arsenic levels in standard reference materials (SRMs) for blood and urine samples.
  • Samples were freeze-dried, irradiated, and analyzed using gamma-ray spectroscopy after separating arsenic from other materials.
  • The results were standardized with values from other labs, yielding certified arsenic concentrations for several levels in the SRMs, while an information value was assigned for one level due to measurement discrepancies.
View Article and Find Full Text PDF
Article Synopsis
  • - The National Institute of Standards and Technology (NIST) and the National Institutes of Health (NIH) created the Standard Reference Material (SRM) 1950 to enhance metabolomics research by providing a reliable reference for metabolite concentrations in human plasma.
  • - SRM 1950 reflects the metabolite profile of adult human plasma, with samples obtained from a diverse group of donors to represent the U.S. population's ethnic composition.
  • - This reference material includes around 100 different analytes such as amino acids and clinical markers, and is the first of its kind specifically designed for the broad applications within the diverse field of metabolomics.
View Article and Find Full Text PDF

Programmers routinely omit run-time safety checks from applications because they assume that these safety checks would degrade performance. The simplest example is the use of arrays or array-like data structures that do not enforce the constraint that indices must be within bounds. This report documents an attempt to measure the performance penalty incurred by two different implementations of bounds-checking in C and C++ using a simple benchmark and a desktop PC with a modern superscalar CPU.

View Article and Find Full Text PDF

A mathematical formulation for a gravimetric approach to the univariate standard addition method (SAM) is presented that has general applicability for both liquids and solids. Using gravimetry rather than volumetry reduces the preparation time, increases design flexibility, and makes increased accuracy possible. SAM has most often been used with analytes in aqueous solutions that are aspirated into flames or plasmas and determined by absorption, emission, or mass spectrometric techniques.

View Article and Find Full Text PDF

Background: Calcium phosphate cement (CPC) hardens in situ to form hydroxyapatite and has been used in dental and craniofacial restorative applications. However, when CPC was used in periodontal osseous repair, tooth mobility resulted in the fracture and exfoliation of the brittle CPC implant. The objective of the authors' study was to develop a strong and nonrigid CPC to provide compliance for tooth mobility without fracturing the implant.

View Article and Find Full Text PDF

Staffs of the Semiconductor Electronics Division, the Information Technology Laboratory, and the Precision Engineering Laboratory at NIST, have developed a new generation of prototype Single-Crystal CD (Critical Dimension) Reference (SCCDRM) Materials with the designation RM 8111. Their intended use is calibrating metrology instruments that are used in semiconductor manufacturing. Each reference material is configured as a 10 mm × 11 mm silicon test-structure chip that is mounted in a 200 mm silicon carrier wafer.

View Article and Find Full Text PDF

To improve the effectiveness of calcium phosphate cement (CPC), we have developed a method to seed osteoblasts into the cement. CPC powder is mixed with water to form a paste that can be shaped to fit a bone defect in situ. The paste hardens in 30 min, reacts to form hydroxyapatite, and is replaced with new bone.

View Article and Find Full Text PDF

A radiochemical neutron activation analysis procedure has been developed, critically evaluated, and shown to have the necessary sensitivity, chemical specificity, matrix independence, and precision to certify phosphorus at ion implantation levels in silicon. 32P, produced by neutron capture of 31P, is chemically separated from the sample matrix and measured using a beta proportional counter. The method is used here to certify the amount of phosphorus in SRM 2133 (Phosphorus Implant in Silicon Depth Profile Standard) as (9.

View Article and Find Full Text PDF

The detection limit is an important figure of merit for evaluating instrumentation and analytical methods. While the detection limit for techniques using linear calibration functions has been studied extensively, this fundamental metric has rarely been discussed for mass spectrometry that bases the calibration on the principle of isotope dilution. We have developed a formulation for the detection limit for isotope dilution mass spectrometry (IDMS) after a thorough analysis of the uncertainty of IDMS measurements.

View Article and Find Full Text PDF

The disposal of ready mixed concrete truck wash water and returned plastic concrete is a growing concern for the ready mixed concrete industry. Recently, extended set-retarding admixtures, or stabilizers, which slow or stop the hydration of portland cement have been introduced to the market. Treating truck wash-water or returned plastic concrete with stabilizing admixtures delays its setting and hardening, thereby facilitating the incorporation of these typically wasted materials in subsequent concrete batches.

View Article and Find Full Text PDF