609 research outputs found
The role of the mobile proton in fucose migration
Fucose migration reactions represent a substantial challenge in the analysis of fucosylated glycan structures by mass spectrometry. In addition to the well-established observation of transposed fucose residues in glycan-dissociation product ions, recent experiments show that the rearrangement can also occur in intact glycan ions. These results suggest a low-energy barrier for migration of the fucose residue and broaden the relevance of fucose migration to include other types of mass spectrometry experiments, including ion mobility-mass spectrometry and ion spectroscopy. In this work, we utilize cold-ion infrared spectroscopy to provide further insight into glycan scrambling in intact glycan ions. Our results show that the mobility of the proton is a prerequisite for the migration reaction. For the prototypical fucosylated glycans Lewis x and blood group antigen H-2, the formation of adduct ions or the addition of functional groups with variable proton affinity yields significant differences in the infrared spectra. These changes correlate well with the promotion or inhibition of fucose migration through the presence or absence of a mobile proton
Expanding the scope of density derived electrostatic and chemical charge partitioning to thousands of atoms
The density derived electrostatic and chemical (DDEC/c3) method is implemented into the onetep program to compute net atomic charges (NACs), as well as higher-order atomic multipole moments, of molecules, dense solids, nanoclusters, liquids, and biomolecules using linear-scaling density functional theory (DFT) in a distributed memory parallel computing environment. For a >1000 atom model of the oxygenated myoglobin protein, the DDEC/c3 net charge of the adsorbed oxygen molecule is approximately -1e (in agreement with the Weiss model) using a dynamical mean field theory treatment of the iron atom, but much smaller in magnitude when using the generalized gradient approximation. For GaAs semiconducting nanorods, the system dipole moment using the DDEC/c3 NACs is about 5% higher in magnitude than the dipole computed directly from the quantum mechanical electron density distribution, and the DDEC/c3 NACs reproduce the electrostatic potential to within approximately 0.1 V on the nanorod’s solvent-accessible surface. As examples of conducting materials, we study (i) a 55-atom Pt cluster with an adsorbed CO molecule and (ii) the dense solids Mo2C and Pd3V. Our results for solid Mo2C and Pd3V confirm the necessity of a constraint enforcing exponentially decaying electron density in the tails of buried atoms
Integrating the little talks intervention into Early Head Start: An experimental examination of implementation supports involving fidelity monitoring and performance feedback
Enriching home visiting services by incorporating scientifically-supported interventions is a means for improving their effectiveness in promoting child development. However, deliberate efforts to ensure that home visitors are fully knowledgeable and supported to implement interventions with parents of young children are necessary. In this experimental study, a randomly-assigned group of Early Head Start home visitors monitored the fidelity of their provision of a scientifically-based intervention, Little Talks, and the program\u27s general child development services. On a bi-weekly basis, home visitors received performance feedback specific to their implementation of Little Talks and based upon the fidelity data. Findings demonstrated that home visitors showed immediate and consistent mastery of the Little Talks content, while the quality of their implementation, including their clinical decision-making and collaborative processes, improved to adequate levels over time. The Little Talks home visitors showed generalized improvements in their ability to obtain Parent Input while providing the program\u27s typical child development services were detected. In fact, Little Talks home visitors\u27 were superior in obtaining Parent Input relative to comparison home visitors. Further, parents for whom low-quality intervention implementation was observed discontinued their enrollment in home visiting prematurely, while high-quality implementation was associated with sustained enrollment. Limitations for this study are identified, leading to future directions for advancing home visitors\u27 incorporation of evidence-based practices
Risk Stratification in Older Intensively Treated Patients With AML
\ua9 2024 by American Society of Clinical Oncology.PURPOSE AML is a genetically heterogeneous disease, particularly in older patients. In patients older than 60 years, survival rates are variable after the most important curative approach, intensive chemotherapy followed by allogeneic hematopoietic cell transplantation (allo-HCT). Thus, there is an urgent need in clinical practice for a prognostic model to identify older patients with AML who benefit from curative treatment. METHODS We studied 1,910 intensively treated patients older than 60 years with AML and high-risk myelodysplastic syndrome (HR-MDS) from two cohorts (NCRIAML18 and HOVON-SAKK). The median patient age was 67 years. Using a random survival forest, clinical, molecular, and cytogenetic variables were evaluated in an AML development cohort (n = 1,204) for association with overall survival (OS). Relative weights of selected variables determined the prognostic model, which was validated in AML (n = 491) and HR-MDS cohorts (n = 215). RESULTS The complete cohort had a high frequency of poor-risk features, including 2022 European LeukemiaNet adverse-risk (57.3%), mutated TP53 (14.4%), and myelodysplasia-related genetic features (65.1%). Nine variables were used to construct four groups with highly distinct 4-year OS in the (1) AML development, (2) AML validation, and (3) HR-MDS test cohorts ([1] favorable: 54% \ub1 4%, intermediate: 38% \ub1 2%, poor: 21% \ub1 2%, very poor: 4% \ub1 1%; [2] 54% \ub1 9%, 43% \ub1 4%, 27% \ub1 4%, 4% \ub1 3%; and [3] 54% \ub1 10%, 33% \ub1 6%, 14% \ub1 5%, 0% \ub1 3%, respectively). This new AML60+ classification improves current prognostic classifications. Importantly, patients within the AML60+ intermediate- and very poor-risk group significantly benefited from allo-HCT, whereas the poor-risk patients showed an indication, albeit nonsignificant, for improved outcome after allo-HCT. CONCLUSION The new AML60+ classification provides prognostic information for intensively treated patients 60 years and older with AML and HR-MDS and identifies patients who benefit from intensive chemotherapy and allo-HCT
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