719 results match your criteria: "National Institute of Standards and Technology (NIST)[Affiliation]"

Commutability is where the measurement response for a reference material (RM) is the same as for an individual patient sample with the same concentration of analyte measured using two or more measurement systems. Assessment of commutability is essential when the RM is used in a calibration hierarchy or to ensure that clinical measurements are comparable across different measurement procedures and at different times. The commutability of three new Standard Reference Materials (SRMs) for determining serum total 25-hydroxyvitamin D [25(OH)D], defined as the sum of 25-hydroxyvitamin D [25(OH)D] and 25-hydroxyvitamin D [25(OH)D], was assessed through an interlaboratory study.

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We describe a modification of a previously described measurement-analysis protocol to determine the intrinsic properties of triaxial accelerometers by using a measurement protocol based on angular stepwise rotation in the Earth's gravitational field. This study was conducted with MEMS triaxial accelerometers that were co-integrated in four consumer-grade wireless microsensors. The measurements were carried out on low-cost rotation tables in different laboratories in different countries to simulate the reproducibility environment encountered in inter-comparisons of calibration capabilities.

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NIST Mass Spectral Libraries in the Context of the Circular Economy of Plastics.

J Am Soc Mass Spectrom

January 2025

Mass Spectrometry Data Center, Biomolecular Measurement Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, 20899, United States.

Article Synopsis
  • The Mass Spectrometry Data Center (MSDC) is enhancing libraries for identifying plastics-related compounds (PRC) and materials (PRM) as part of NIST's circular economy initiative.
  • To increase the diversity of compounds analyzed, MSDC is utilizing three ionization methods: EI, ESI, and APCI, along with pyrolysis-gas chromatography (py-GC-MS) for solid materials.
  • Collaborating with agencies like the FDA and EPA, they are testing these libraries to address health risks and environmental issues concerning plastics.
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Atomic Ordering-Induced Ensemble Variation in Alloys Governs Electrocatalyst On/Off States.

J Am Chem Soc

January 2025

Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States.

The catalytic behavior of a material is influenced by ensembles─the geometric configuration of atoms on the surface. In conventional material systems, ensemble effects and the electronic structure are coupled because these strategies focus on varying the material composition, making it difficult to understand the role of ensembles in isolation. This study introduces a methodology that separates geometric effects from the electronic structure.

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Somatic mosaicism is an important cause of disease, but mosaic and somatic variants are often challenging to detect because they exist in only a fraction of cells. To address the need for benchmarking subclonal variants in normal cell populations, we developed a benchmark containing mosaic variants in the Genome in a Bottle Consortium (GIAB) HG002 reference material DNA from a large batch of a normal lymphoblastoid cell line. First, we used a somatic variant caller with high coverage (300x) Illumina whole genome sequencing data from the Ashkenazi Jewish trio to detect variants in HG002 not detected in at least 5% of cells from the combined parental data.

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Mass spectral libraries are collections of reference spectra, usually associated with specific analytes from which the spectra were generated, that are used for further downstream analysis of new spectra. There are many different formats used for encoding spectral libraries, but none have undergone a standardization process to ensure broad applicability to many applications. As part of the Human Proteome Organization Proteomics Standards Initiative (PSI), we have developed a standardized format for encoding spectral libraries, called mzSpecLib (https://psidev.

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We present a versatile optical setup for high-resolution neutron imaging with an adaptable field of view and magnification that can resolve individual neutron absorption events with an image intensifier and a CMOS camera. Its imaging performance is characterized by evaluating the resolution limits of the individual optical components and resulting design aspects are discussed. Neutron radiography measurements of a Siemens star pattern were performed in event mode acquisition comparing two common high-resolution neutron scintillators, crystalline Gadolinium Gallium Garnet (GGG) and powdered Gadolinium Oxysulfide (GOS).

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Introduction: Human metabolomics has made significant strides in understanding metabolic changes and their implications for human health, with promising applications in diagnostics and treatment, particularly regarding the gut microbiome. However, progress is hampered by issues with data comparability and reproducibility across studies, limiting the translation of these discoveries into practical applications.

Objectives: This study aims to evaluate the fit-for-purpose of a suite of human stool samples as potential candidate reference materials (RMs) and assess the state of the field regarding harmonizing gut metabolomics measurements.

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Federated Learning (FL) has emerged as a means of distributed learning using local data stored at clients with a coordinating server. Recent studies showed that FL can suffer from poor performance and slower convergence when training data at the clients are not independent and identically distributed (IID). Here, we consider auxiliary server learning as a approach to improving the performance of FL on non-IID data.

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Nucleic acid sequencing technologies have gone through extraordinary advancements in the past several decades, significantly increasing throughput while reducing cost. To create similar advancement in proteomics, numerous approaches are being investigated to advance protein sequencing. One of the promising approaches uses N-terminal amino acid binders (NAABs), also referred to as recognizers, that selectively can identify amino acids at the N-terminus of a peptide.

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Phase transitions in random circuit sampling.

Nature

October 2024

Google Research, Mountain View, CA, USA.

Undesired coupling to the surrounding environment destroys long-range correlations in quantum processors and hinders coherent evolution in the nominally available computational space. This noise is an outstanding challenge when leveraging the computation power of near-term quantum processors. It has been shown that benchmarking random circuit sampling with cross-entropy benchmarking can provide an estimate of the effective size of the Hilbert space coherently available.

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Article Synopsis
  • - The paper explores the quantum anomalous Hall (QAH) effect in a resistor made from Chromium-doped Bismuth Antimony Telluride, aimed at linking it with a programmable Josephson voltage standard (PJVS) without using a magnetic field.
  • - Precision measurements of the QAH resistance were conducted while applying a microwave signal to the PJVS, which enhances the accuracy of the resistance readings.
  • - The findings aim to enhance experimental setups for combining various quantum electrical standards into one cohesive system, which could lead to advancements in quantum technology.
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Article Synopsis
  • Standard information reporting is essential for consistent assay conditions and data, enabling easier comparisons between laboratories.
  • The publication presents the Minimum Information for Reporting on the TEER assay (MIRTA), a key method used to assess cell culture models and toxicity potential.
  • Developed through an international collaboration, the recommendations from the RespTox Collaborative aim to improve data transparency, reproducibility, and quality in both respiratory and other cell systems.
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Article Synopsis
  • High-crystal-quality nanoferrites with short ligands, like oleic acid, have been found to improve sensitivity and spatial resolution in magnetic particle imaging (MPI) due to their ability to form uniaxial assemblies.
  • A one-pot thermal decomposition method was developed to create magnetic nano-objects (MNOs) that show strong magnetic interactions and reproducibility, with sizes ranging from 12 to 27 nm, affecting their response and chain formation capabilities.
  • The study revealed that these ferrite MNOs significantly enhance signal and spatial resolution compared to existing MPI tracers, with results indicating the importance of optimizing the frequency and field amplitude for effective imaging and thermal performance.
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On-Chip Synthesis of Quasi-2D Semimetals from Multi-Layer Chalcogenides.

Adv Mater

November 2024

Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA.

Reducing the dimensions of materials from three to two, or quasi-two, provides a fertile platform for exploring emergent quantum phenomena and developing next-generation electronic devices. However, growing high-quality, ultrathin, quasi2D materials in a templated fashion on an arbitrary substrate is challenging. Here, the study demonstrates a simple and reproducible on-chip approach for synthesizing non-layered, nanometer-thick, quasi-2D semimetals.

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Topological insulators (TI) and magnetic topological insulators (MTI) can apply highly efficient spin-orbit torque (SOT) and manipulate the magnetization with their unique topological surface states (TSS) with ultrahigh efficiency. Here, efficient SOT switching of a hard MTI, V-doped (Bi,Sb)Te (VBST), with a large coercive field that can prevent the influence of an external magnetic field, is demonstrated. A giant switched anomalous Hall resistance of 9.

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The quantum Hall (QH) effect is one of the most widely studied physical phenomenon in two dimensions. The plateau-plateau transition within this effect can be comprehensively described by the scaling theory, which encompasses three pivotal exponents: the critical exponent κ, the inelastic scattering exponent p, and the universal exponent γ. Prior studies have focused on measuring κ and estimating γ, assuming a constant p value of 2 across magnetic fields.

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The protein dynamical transition at ~200 K, where the biomolecule transforms from a harmonic, non-functional form to an anharmonic, functional state, has been thought to be slaved to the thermal activation of dynamics in its surface hydration water. Here, by selectively probing the dynamics of protein and hydration water using elastic neutron scattering and isotopic labeling, we found that the onset of anharmonicity in the two components around 200 K is decoupled. The one in protein is an intrinsic transition, whose characteristic temperature is independent of the instrumental resolution time, but varies with the biomolecular structure and the amount of hydration, while the one of water is merely a resolution effect.

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Biocompatibility testing using in vivo tests is often one of the final evaluations of new dental materials. To reduce the likelihood of failure at this late stage, predictive biocompatibility testing using in vitro methods is needed. In this study, we describe a sensitivity analysis of an oral irritation test by evalu­ating changes in the viability, using the MTT assay, of 3-D models with EpiOral constructs as a case study.

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Nondispersive ultraviolet visible gas analyzer designs were evaluated for monitoring molybdenum-containing chloride and oxychloride precursor delivery during microelectronics vapor deposition processes. The performances of three analyzer designs, which differed only in the bandpass filter employed for wavelength selection, were compared for measuring the partial pressure of molybdenum pentachloride, molybdenum oxytetrachloride (MoOCl), and molybdenum dioxydichloride (MoOCl). The analyzer's optical response with a 369 nm center wavelength filter for molybdenum pentachloride was determined by measuring the molybdenum pentachloride absorbance as a function of vapor molar density.

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Solution Synthesis of NdTe Magnetic Nanosheets.

Chem Mater

July 2024

Department of Chemistry, Georgetown University, 37th and O Sts. NW, Washington, D.C. 20057, United States.

Neodymium tritelluride is a layered van der Waals material, with correlated electronic properties including high electronic mobility, charge density waves, and antiferromagnetism. We developed a solution synthesis method to form free-standing nanosheets of NdTe, with nanosheet lateral dimensions of 200-400 nm. The morphology of the nanosheet was influenced by the neodymium precursor.

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Measurement of total bilirubin (TBil) concentration in serum is the gold standard approach for diagnosing neonatal unconjugated hyperbilirubinemia. It is of utmost importance that the measured TBil concentration is sufficiently accurate to prevent under treatment, unnecessary escalation of care, or overtreatment. However, it is widely recognized that TBil measurements urgently require improvement in neonatal clinical chemistry.

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Recent advancements in materials science have shed light on the potential of exploring hierarchical assemblies of molecules on surfaces, driven by both fundamental and applicative challenges. This field encompasses diverse areas including molecular storage, drug delivery, catalysis, and nanoscale chemical reactions. In this context, the utilization of nanotube templates (NTs) has emerged as promising platforms for achieving advanced one-dimensional (1D) molecular assemblies.

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Economic and environmental considerations have elucidated research interests on the best approach to managing electronic waste (e-waste), which has increasing social, environmental, and economic impacts. Proper e-waste managementis essential for resource recovery, environmental sustainability, and public health protection, and effective management of e-waste necessitates analytical techniques to assess and characterize their elemental composition. Despite expansive literature published on the topic of e-waste, there is scarce coverage of the various analytical techniques employed to characterize the inorganic contents of e-waste.

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Introduction: During the Metabolomics 2023 conference, the Metabolomics Quality Assurance and Quality Control Consortium (mQACC) presented a QA/QC workshop for LC-MS-based untargeted metabolomics.

Objectives: The Best Practices Working Group disseminated recent findings from community forums and discussed aspects to include in a living guidance document.

Methods: Presentations focused on reference materials, data quality review, metabolite identification/annotation and quality assurance.

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