11,208 results match your criteria: "‡National Institute of Standards and Technology[Affiliation]"

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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Thermodynamic compensation to temperature extremes in B. subtilis vs T. maritima lysine riboswitches.

Biophys J

October 2024

JILA, University of Colorado Boulder and National Institute of Standards and Technology, Boulder, Colorado; Department of Chemistry, University of Colorado Boulder, Boulder, Colorado; Department of Physics, University of Colorado Boulder, Boulder, Colorado. Electronic address:

T. maritima and B. subtilis are bacteria that inhabit significantly different thermal environments, ∼80 vs.

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The DNA Commission of the International Society for Forensic Genetics (ISFG) has developed a set of nomenclature recommendations for short tandem repeat (STR) sequences. These recommendations follow the 2016 considerations of the DNA Commission of the ISFG, incorporating the knowledge gained through research and population studies in the intervening years. While maintaining a focus on backward compatibility with the CE data that currently populate national DNA databases, this report also looks to the future with the establishment of recommended minimum sequence reporting ranges to facilitate interlaboratory comparisons, automated solutions for sequence-based allele designations, a suite of resources to support bioinformatic development, guidance for characterizing new STR loci, and considerations for incorporating STR sequences and other new markers into investigative databases.

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Understanding molecular state evolution is central to many disciplines, including molecular dynamics, precision measurement, and molecule-based quantum technology. Details of this evolution are obscured when observing a statistical ensemble of molecules. Here, we report real-time observations of thermal radiation-driven transitions between individual states ("jumps") of a single molecule.

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Incorporation of polymer chain entanglements within a single network can synergistically improve stiffness and toughness, yet attaining such dense entanglements through vat photopolymerization additive manufacturing [e.g., digital light processing (DLP)] remains elusive.

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Bridging length scales in hard materials with ultra-small angle X-ray scattering - a critical review.

IUCrJ

September 2024

X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA.

Article Synopsis
  • Hard materials like ceramics, metals, and composites are valuable for various industries, making it essential to understand their microstructural characteristics for performance enhancement and innovation.
  • The review highlights ultra-small angle X-ray scattering (USAXS), which is a nondestructive technique to analyze the nano-to-micrometer features in hard materials, offering insights into aspects like porosity and grain size.
  • The authors discuss the techniques' principles, its advantages, challenges in the characterization process, and propose future opportunities in USAXS research, aiming to encourage its broader use in hard materials science.
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Certified reference material (CRM) for natural (K,Pb,Po,Ra,Ra,Th,Th,Th,U,U, andU) and anthropogenic (Cs,Pu, andAm) radionuclides in marine sediment from the Baltic Sea (IAEA-465) has been developed. Information values are given for Pu,Pu andPu. Altogether 27 laboratories participated in this exercise.

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Advances in yeast synthetic biology for human G protein-coupled receptor biology and pharmacology.

Curr Opin Biotechnol

August 2024

Department of Molecular and Cellular Pharmacology, University of Miami School of Medicine, USA; Sylvester Comprehensive Cancer Center, Tumor Biology Program, USA; Frost Institute for Data Science and Computing, USA.

G protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors in humans. Over 800 GPCRs regulate the (patho)biology of every organ, tissue, and cell type. Consequently, GPCRs are the most prominent therapeutic targets in medicine.

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Glycans are oligosaccharides attached to proteins or lipids and affect their functions, such as drug efficacy, structural contribution, metabolism, immunogenicity, and molecular recognition. Conventional glycosylation analysis has relied on destructive, slow, system-sensitive methods, including enzymatic reactions, chromatography, fluorescence labeling, and mass spectrometry. Herein, we propose quantum cascade laser (QCL) infrared (IR) spectroscopy as a rapid, nondestructive method to quantify glycans and their monosaccharide composition.

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Clock with 8×10^{-19} Systematic Uncertainty.

Phys Rev Lett

July 2024

JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA.

We report an optical lattice clock with a total systematic uncertainty of 8.1×10^{-19} in fractional frequency units, representing the lowest uncertainty of any clock to date. The clock relies on interrogating the ultranarrow ^{1}S_{0}→^{3}P_{0} transition in a dilute ensemble of fermionic strontium atoms trapped in a vertically-oriented, shallow, one-dimensional optical lattice.

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Article Synopsis
  • Scientists studied how a special type of gel, made from three different building blocks, changes when heated.
  • At normal temperatures, these gels form tiny ball-like structures in water.
  • When heated, the gel changes shape, forming a network that can look different based on the lengths of the building blocks used to make it.
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Traditional technologies for far-infrared (FIR) spectroscopy generally involve bulky dispersive optics. Integrated filter bank spectrometers promise more compact designs, but implementations using superconducting transmission line networks become lossy at terahertz frequencies. We describe a novel on-chip spectrometer architecture designed to extend this range.

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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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Article Synopsis
  • COVID-19 had a significant impact on minority communities, highlighting the need for better research engagement with these groups, while existing evaluation methods hinder comprehensive analysis.
  • A cross-sectional study in Massachusetts showed that 91.4% of 290 participants had received a COVID-19 vaccine, and 41.7% reported past infections, with findings indicating varying antibody responses and lingering symptoms, particularly among middle-aged Latinas.
  • The study emphasized the importance of using saliva samples for serology and introduced standardized methods for better future evaluations, enhancing the understanding of COVID-19 and public health responses in underserved populations.
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Quantitative Analysis of Complement Membrane Attack Complex Proteins Associated with Extracellular Vesicles.

Proteomes

July 2024

Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology, University of Maryland, Rockville, ML 20850, USA.

Extracellular vesicles (EVs) represent a universal mechanism of intercellular communication in normal and pathological conditions. There are reports showing the presence of complement proteins in EV preparations, specifically those that can form a membrane attack complex (MAC). In the present work, we have used a quantitative mass spectrometry method that allows for the measurement of multiple targeted proteins in one experimental run.

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Article Synopsis
  • - The study focused on modifying high-amylose maize starch by debranching it to enhance linear molecule formation and create spherulites, which are specific crystalline structures.
  • - After heating the starch at 180 °C and crystallizing it at various temperatures, researchers found that crystallization at 150 °C resulted in less stable spherulites with negative birefringence, indicating molecular degradation and reduced digestion resistance.
  • - In contrast, spherulites crystallized at temperatures between 25 to 120 °C displayed strong positive birefringence, a more stable structure, and high levels of resistant starch, as α-amylase could not penetrate these structures effectively.
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Highly concentrated aqueous electrolytes (termed water-in-salt electrolytes, WiSEs) at solid-liquid interfaces are ubiquitous in myriad applications including biological signaling, electrosynthesis, and energy storage. This interface, known as the electrical double layer (EDL), has a different structure in WiSEs than in dilute electrolytes. Here, we investigate how divalent salts [zinc bis(trifluoromethylsulfonyl)imide, Zn(TFSI)], as well as mixtures of mono- and divalent salts [lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) mixed with Zn(TFSI)], affect the short- and long-range structure of the EDL under confinement using a multimodal combination of scattering, spectroscopy, and surface forces measurements.

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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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In 2015, a study showed that Krypton-Chloride (KrCl) excimer lamps could induce erythema and basal layer DNA damage in human skin. Later studies found that filtering out longer wavelength emissions from these lamps resulted in no acute skin effects. However, there is a limited understanding of how much to reduce unwanted emissions and which wavelengths are important.

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As a neighbor of carbon in the periodic table, boron exhibits versatile structural and electronic configurations, with its allotropes predicted to possess intriguing structures and properties. Since the experimental realization of two-dimensional (2D) boron sheets (borophene) on Ag(111) substrates in 2015, the experimental study of the realization and characteristics of borophene has drawn increasing interest. In this review, we summarize the synthesis and properties of borophene, which are mainly based on experimental results.

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Prokaryotic transcription factors can be repurposed into biosensors for the ligand-inducible control of gene expression, but the landscape of chemical ligands for which biosensors exist is extremely limited. To expand this landscape, we developed Ligify, a web application that leverages information in enzyme reaction databases to predict transcription factors that may be responsive to user-defined chemicals. Candidate transcription factors are then incorporated into automatically generated plasmid sequences that are designed to express GFP in response to the target chemical.

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Magnetic skin effect in Pb(Fe _{1/2}$Nb _{1/2}$)O.

J Phys Condens Matter

July 2024

School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom.

Article Synopsis
  • Relaxor-ferroelectrics are materials with unique dielectric properties due to random dipolar fields created by strong chemical inhomogeneity, displaying a significant skin effect where surface structures differ from the bulk over a length of approximately 100 μm.
  • A study of Pb(Fe_{1/2}Nb_{1/2})O (PFN) showed it has ferroelectric and relaxor-like dielectric characteristics, along with antiferromagnetism, indicating it is a multiferroic material.
  • Using muon spectroscopy, the research revealed depth-dependent magnetic relaxation behaviors in PFN, demonstrating a magnetic skin effect similar to that seen in its structural properties, while the chemical concentration variations alone did not explain these dynamics.
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Article Synopsis
  • The research investigates how manipulating spin-phonon coupling in two-dimensional van der Waals ferromagnetic semiconductors can enhance magnetism, opening new possibilities for spintronic devices.
  • The study uses tetrabutyl ammonium (TBA) as an intercalant to show its effects on the magnetic and electronic properties of CrGeTe, revealing increased ferromagnetic Curie temperature through temperature evolution of Raman modes and magnetization measurements.
  • The findings point to significant electron transfer from TBA to Cr, emphasizing the importance of spin-phonon interaction and magnetic ordering in understanding and controlling magnetism in layered structures.
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