Publications by authors named "Ri Wu"

Probing the structural characteristics of biomolecular ions in the gas phase following native mass spectrometry (nMS) is of great interest, because noncovalent interactions, and thus native fold features, are believed to be largely retained upon desolvation. However, the conformation usually depends heavily on the charge state of the species investigated. In this study, we combine transition metal ion Förster resonance energy transfer (tmFRET) and ion mobility-mass spectrometry (IM-MS) with molecular dynamics (MD) simulations to interrogate the β-hairpin structure of GB1p in vacuo.

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A cytopathology fellowship match would create an enforced and structured recruitment timeline for the benefit of applicants and programs. Major benefits would include delaying fellowship applications to allow residents to explore different subspecialty areas, a standardized application process for administrative ease, and optimization of matches between applicants and programs based on ranked preferences rather than use of time-limited "exploding offers." The overall gains in efficiency and achieving the primary goals of supporting trainees and recruiting in an equitable and inclusive manner outweigh any downsides to instituting a cytopathology fellowship match.

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Article Synopsis
  • Recent research shows that small peptides can prevent the aggregation of amyloid-β (Aβ) by altering its structure, but studying these interactions, especially with metal ions, is complex.
  • A novel method combining transition metal ion Förster resonance energy transfer (tmFRET) and ion mobility-mass spectrometry was used to analyze Aβ complexes with Cu(II) ions and the aggregation inhibitor leucine enkephalin (LE).
  • The study found that upon Cu(II) binding, Aβ's structure changes significantly, and the introduction of LE helped identify how these molecules interact, revealing important information about the binding region and the inhibitor's orientation.
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Gas-phase Förster resonance energy transfer (FRET) combines mass spectrometry and fluorescence spectroscopy for the conformational analysis of mass-selected biomolecular ions. In FRET, fluorophore pairs are typically covalently attached to a biomolecule using short linkers, which affect the mobility of the dye and the relative orientation of the transition dipole moments of the donor and acceptor. Intramolecular interactions may further influence the range of motion.

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Acute myeloid leukemia (AML) is a highly heterogeneous subtype of hematological malignancies with a wide spectrum of cytogenetic and molecular abnormalities, which makes it difficult to manage and cure. Along with the deeper understanding of the molecular mechanisms underlying AML pathogenesis, a large cohort of novel targeted therapeutic approaches has emerged, which considerably expands the medical options and changes the therapeutic landscape of AML. Despite that, resistant and refractory cases caused by genomic mutations or bypass signalling activation remain a great challenge.

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Mass spectrometry is a powerful technique for the structural and functional characterization of biomolecules. However, it remains challenging to accurately gauge the gas-phase structure of biomolecular ions and assess to what extent native-like structures are maintained. Here we propose a synergistic approach which utilizes Förster resonance energy transfer and two types of ion mobility spectrometry (i.

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The conformation and function of somatostatin (SST), a cyclic neuropeptide, was recently found to be altered in the presence of Cu(II) ions, which leads to self-aggregation and loss of biological function as a neurotransmitter. However, the impact of Cu(II) ions on the structure and function of SST is not fully understood. In this work, transition metal ion Förster resonance energy transfer (tmFRET) and native ion mobility-mass spectrometry (IM-MS) were utilized to study the structures of well-defined gas-phase ions of SST and of a smaller analogue, octreotide (OCT).

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Fellowship recruitment and retention of a skilled workforce is one of the biggest challenges that not only cytopathology is facing but that the field of pathology in general is being confronted with. There have long been issues with the fellowship recruitment process for both applicants and fellowship directors, including pressure to move the application process earlier and earlier and frustrations stemming from applicants needing to determine different individual timelines and program requirements. The unified timeline for fellowship recruitment was established as an attempt to standardize the recruitment process and to address the key issues of the push for earlier and earlier decision-making, which placed significant anxiety on trainees, as well as the burden on programs of more unexpected openings.

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Reactive oxygen species (ROS) are critical for many cellular functions, and dysregulation of ROS involves the development of multiple types of tumors, including pancreatic cancer. However, ROS have been grouped into a single biochemical entity for a long time, and the specific roles of certain types of ROS in tumor cells (e.g.

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Native mass spectrometry has emerged as an important tool for gas-phase structural biology. However, the conformations that a biomolecular ion adopts in the gas phase can differ from those found in solution. Herein, we report a synergistic, native ion mobility-mass spectrometry (IM-MS) and transition metal ion Förster resonance energy transfer (tmFRET)-based approach to probe the gas-phase ion structures of a nonstapled peptide (nsp; Ac-CAARAAHAAAHARARA-NH) and a stapled peptide (sp; Ac-CARAHAAAHARARA-NH).

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Three dissociation methods, including collision-induced dissociation (CID), electron capture dissociation (ECD), and electronic excitation dissociation (EED), were evaluated for the dissociation of doubly charged glycans using sodium or magnesium ions as charge carriers. CID produced mainly glycosidic cleavages, although more cross-ring fragment ions could be obtained at higher intensities when magnesium ions were used as charge carriers [M + Mg]. The A, A, and A ions provided structural information on the 3 → 1 and 6 → 1 linkages of the mannoses.

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Single-cell metabolomics is expected to deliver fast and dynamic information on cell function; therefore, it requires rapid analysis of a wide variety of very small quantities of metabolites in living cells. In this work, a hybrid ionization source that combines nanoelectrospray ionization (nanoESI) and dielectric barrier discharge ionization (DBDI) is proposed for single-cell analysis. A capillary with a 1 μm i.

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The current matrix deposition methods in MALDI-mass spectrometry imaging (MALDI-MSI) face technical problems related to the inhomogeneous distribution of crystals and the low analyte extraction and cocrystallization efficiency. In this work, an integrated matrix sublimation device with synchronous solvent nebulization was developed for MALDI-MSI. Droplets of solvents were directly introduced into the chamber of the sublimator by using a miniaturized ultrasonic nebulizer unit.

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Gas-phase fluorescence spectroscopy is still in its infancy, which demands further instrumental developments. In this study, a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS), equipped with a lab-developed data acquisition system, was coupled to a tunable femtosecond laser and a state-of-the-art optical system for fluorescence studies of mass-selected ions. For excitation, a laser beam was focused (beam size < 1.

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Structural studies of mass-selected biomolecules in the gas phase can reveal their intrinsic properties and provide useful benchmarks for biomolecular modeling. Here, we report the first evidence of transition metal ion FRET (tmFRET) in the gas phase and its application to measure short (10-40 Å) biomolecular backbone distances. The measured FRET efficiencies in rhodamine dye (donor) labeled helical peptides complexed with Cu ions (acceptor) decreased with increasing donor - acceptor distances, confirming the occurrence of tmFRET.

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Introduction: Cytopathology fellows are required to enter their fine-needle aspiration (FNA) case numbers in an online data collection system, the Accreditation Council for Graduate Medical Education (ACGME) Case Log system. This study reviewed this data to examine trends in FNA case numbers during fellowship training.

Methods: A retrospective review of the ACGME Accreditation Data System (ADS) FNA Case Log data was performed for academic years 2006-2019.

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Introduction: Cytopathology is one of the most sought-after fellowships within pathology, with a lower fellowship vacancy rate compared with most other subspecialties. The Accreditation Council for Graduate Medical Education (ACGME) actively tracks annual program data for cytopathology fellowship programs, and evaluating this longitudinal data looking at trends in programs and positions over the past 10 years could provide insights into the future of cytopathology and its training programs.

Methods: Data obtained from the ACGME was examined in detail for all ACGME-accredited cytopathology fellowship programs over the past decade (2011-2021).

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Introduction: Cytopathology (CYP) fellowship training is a critical component of maintaining a skilled group of cytopathologists. For years, the recruitment process for CYP fellowship programs has remained unchanged, with individual programs outlining their own requirements and timeline, and applicants bearing the cost of travel and dealing with the variable processes outlined by individual programs. However, there has been renewed interest in analyzing the recruitment process for CYP fellowships to look for areas of potential improvement and uniformity.

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The size and distribution of matrix crystals deposited on the surface of a tissue section play a key role in the performance of MALDI mass spectrometry imaging (MALDI-MSI). In this study, uniform distribution and a restricted size of matrix crystals were achieved via a homemade matrix sublimation device with controllable crystallization temperature. The crystallization temperature was stably controlled at a subzero temperature, and homogeneous matrix crystals with diameters <0.

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In this work, the sorbent-attached microfunnels used in funnel-based spray ionization mass spectrometry were evaluated for the all-in-one digestion of proteins. Sorbent materials, including C and TiO powders, were used as substrates to support in-funnel digestion and subsequent solid-phase extraction and purification of the digested products. In-funnel digestion protocols with and without reductive alkylation were developed for the analysis of proteins with and without disulfide linkages.

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A sandwich-type surface-enhanced Raman scattering (SERS) sensor using dual aptamers and gold-enhanced Raman signal probes has been successfully constructed for the detection of tumor-derived extracellular vesicles. The simple and sensitive sensor has the capability to detect tumor extracellular vesicles in 10-fold diluted human serum samples.

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Context.—: Social media sites are increasingly used for education, networking, and rapid dissemination of medical information, but their utility for facilitating research has remained largely untapped.

Objective.

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