bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ligand-field theory applied to diatomic transition metals. Results for the d
A9d
B9σ2 states of Ni2, the dNi9dCu10σ2 states of NiCu, and the dNi8(3F)dCu10σ2σ*1 excited states of NiCu
Authors: Spain Eileen M. , Morse Michael D. 
Published: July 2002

A ligand-field theory has been developed for transition-metal diatomics having electronic configurations of dA9dB10σ2, dA9dB9σ2, and dA8(3F)dB10σ2σ*1. The theory treats each atom as a point charge and includes spin–orbit interactions. No contributions due to d-orbital chemical bonding are included. Since the d orbitals are quite small compared to the bond lengths in these molecules, the only inputs to the theory are the ligand charges (ZA and ZB), the radial expectation values &lt;rA2≳nd, &lt;rB2≳nd, &lt;rA4≳nd, and &lt;rB4≳nd, the atomic spin–orbit parameters ζA and ζB, and the bond length, R. Calculations employing no adjustable parameters (setting ZA, B =+1.0, and using radial expectation values and spin–orbit parameters from atomic tables) provide essentially quantitative agreement with ab initio results on the dNi9dCu10σ2 manifold of states in NiCu, and on the dA9dB9σ2 manifold of states in Ni2.
This demonstrates that the ligand-field model has some validity for metal molecules containing nickel, primarily because of the compact nature of the 3d orbitals in this element. Similar calculations of the dA9dB9σ2 manifold of states in Pt2 and the dNi9dPt9σ2 manifold of states in NiPt are presented for comparison to future ab initio or experimental measurements, although the possibility of d-orbital contributions to the bonding in these species makes the ligand-field model less favorable in these examples. The dNi8(3F)dCu10σ2σ*1 excited electronic states of NiCu, which are well known from resonant two-photon ionization spectroscopy, are also investigated in the ligand-field model. As a final example, the dNi8(3F)σ2σ*1 excited electronic states of NiH are also examined using the same treatment as that employed for the dNi8(3F)dCu10σ2σ*1 excited manifold of NiCu.
Application of integral equation theories to predict the structure of diatomic fluids
Authors: Lue Leo , Blankschtein Daniel 
Published: July 2002

We compare the capabilities of the site–site Ornstein–Zernike equation and the Chandler–Silbey–Ladanyi equations to predict the fluid structure for: (i) fluids composed of homonuclear diatomic Lennard-Jones molecules, and (ii) fluids composed of nonpolar or polar heteronuclear diatomic Lennard-Jones molecules. In (i), we solve the site–site Ornstein–Zernike (SSOZ) equation with the Percus–Yevick (PY) closure, and the Chandler–Silbey–Ladanyi (CSL) equations with the hypernetted-chain (HNC) closure to predict the various pair correlation functions at various bond lengths, fluid densities, and temperatures. In general, we find that the CSL equations become more accurate, when compared with computer simulation results, as the bond length increases or as the density decreases, with temperature having no significant effect. In fact, at densities below the critical density, the fluid structure predictions of the CSL equations are found to be in closer agreement with the computer simulation results than those of the SSOZ equation. We also present a general method for computing the low-order density bridge functions in the context of the CSL equations. In the case of homonuclear diatomic molecules, the zeroth-order bridge functions, B(0), are found to have little effect on the pair correlation function predictions of the CSL equations. However, the addition of the first-order bridge functions, B(1), results in a significant improvement of these predictions.
In general, the accuracy of the CSL equations, including the various bridge function corrections, is found to increase as the bond length increases or as the density decreases, similar to what we found when the HNC closure (in which the bridge functions are set equal to zero) was used. Finally, in (ii), we find that for nonpolar heteronuclear diatomic fluids, the CSL equations, with the HNC, HNC+B(0), and HNC+B(1) closures, perform very well in predicting the correlation functions between the larger interactions sites. For polar heteronuclear diatomic fluids, we find that the CSL equations seem to offer an improvement over the SSOZ equation. Once again, the CSL equations provide better predictions for the correlation function between the larger interaction sites.
Dipole–dipole coupling effects upon infrared spectroscopy of compressed electrochemical adlayers: Application to the Pt(111)/CO system
Authors: Severson Mark W. , Stuhlmann Christopher , Villegas Ignacio , Weaver Michael J. 
Published: July 2002

Experimental infrared spectra for CO adlayers on Pt(111) electrodes having known real-space structures as deduced by scanning tunneling microscopy are compared with predictions extracted from conventional dipole–dipole coupling models in order to test the validity of such treatments for compressed electrochemical adlayers, especially with regard to band-intensity transfer effects. The specific structures considered are (2×2)–3CO and (√19×√19)R23.4°–13CO hexagonal adlayers; the former is especially close packed (θCO=0.75) with a pair of threefold hollow and one atop CO per unit cell, while the latter has a lower coverage (θCO=13/19) and involves largely asymmetric binding sites. The comparisons between dipole-coupling theory and experiment include infrared spectra for various 13CO/12CO mixtures, thereby exploiting the well-known systematic alterations which are induced in the degree of coupling for a given adlayer. Consistent with an earlier assessment (Ref. ) the conventional dipole–dipole treatment can account semiquantitatively for the marked higher intensity of the atop relative to the threefold hollow C–O stretching band in the observed infrared spectra even though the occupancy on the latter site is twofold greater and the singleton frequencies are substantially (∼280 cm−1) different. This coupling-induced intensity transfer toward the higher-frequency band component is likely to be a widespread phenomenon for densely packed adlayers.
For the (2×2) adlayer, however, the isotope composition-dependent spectral band frequencies and relative intensities deviate markedly from the experiment. While the inclusion of stochastic broadening effects associated with adlayer disorder improves the situation, a satisfactory fit between theory and experiment requires the incorporation of vibrational coupling associated with short-range intermolecular interactions. For the (√19×√19) adlayer, on the other hand, dipole–dipole coupling with stochastic broadening accounts well for the observed spectral behavior. The more pronounced limitation of the conventional theory for the (2×2) structure may well be due to the abnormally high adsorbate packing density enhancing the importance of short-range interactions.
Public service broadcasting in Italy: Historical trends and future prospects
Authors: Hibberd Matthew 
Published: July 2002

SummaryThe article outlines the current structure and organization of public service broadcasting in Italy and explores various options for its future development. With moves towards digital broadcasting, RAI is set to enter a discrete next stage which will bring new challenges and will inevitably lead to a revision of its public service remit. While it is currently unclear how far Italian public service broadcasting will change, there is evidence that members of the government and senior RAI managers wish partially to privatize core elements of its public service. Focusing on the development of television, the article addresses some of the salient issues facing RAI and other public service broadcasters who have become the victims of a pervasive disenchantment with public provision of goods and services.
RRTree: Relative-Rate Tests between groups of sequences on a
phylogenetic tree
Authors: Robinson-Rechavi Marc , Huchon Dorothée 
Published: July 2002

Abstract
*To whom correspondence should be addressed.
3Present address: Laboratoire de Biologie Moléculaire et Cellulaire, Ecole Normale Supérieure de Lyon, 6 allée d’Italie, 69364 Lyon cedex 07, France, marc.robinson@ens-lyon.fr
Summary: RRTree is a user-friendly program for comparing substitution rates between lineages of protein or DNA sequences, relative to an outgroup, through relative rate tests. Genetic diversity is taken into account through use of several sequences, and phylogenetic relations are integrated by topological weighting.
Availability: The ANSI C source code of RRTree, and compiled versions for Macintosh, MS-DOS/Windows, SUN Solaris, and CGI, are freely available at http://pbil.univ-lyon1.fr/software/rrtree.html
Contact: marc.robinson@ens-lyon.fr
Prevalence and Correlates of Long COVID Symptoms Among US Adults
Authors: Perlis Roy H. , Santillana Mauricio , Ognyanova Katherine , Safarpour Alauna , Lunz Trujillo Kristin , Simonson Matthew D. , Green Jon , Quintana Alexi , Druckman James , Baum Matthew A. , Lazer David 
Published: October 2022

ImportancePersistence of COVID-19 symptoms beyond 2 months, or long COVID, is increasingly recognized as a common sequela of acute infection.ObjectivesTo estimate the prevalence of and sociodemographic factors associated with long COVID and to identify whether the predominant variant at the time of infection and prior vaccination status are associated with differential risk.Design, Setting, and ParticipantsThis cross-sectional study comprised 8 waves of a nonprobability internet survey conducted between February 5, 2021, and July 6, 2022, among individuals aged 18 years or older, inclusive of all 50 states and the District of Columbia.Main Outcomes and MeasuresLong COVID, defined as reporting continued COVID-19 symptoms beyond 2 months after the initial month of symptoms, among individuals with self-reported positive results of a polymerase chain reaction test or antigen test.ResultsThe 16 091 survey respondents reporting test-confirmed COVID-19 illness at least 2 months prior had a mean age of 40.5 (15.2) years; 10 075 (62.6%) were women, and 6016 (37.4%) were men; 817 (5.1%) were Asian, 1826 (11.3%) were Black, 1546 (9.6%) were Hispanic, and 11 425 (71.0%) were White. From this cohort, 2359 individuals (14.7%) reported continued COVID-19 symptoms more than 2 months after acute illness. Reweighted to reflect national sociodemographic distributions, these individuals represented 13.9% of those who had tested positive for COVID-19, or 1.7% of US adults. In logistic regression models, older age per decade above 40 years (adjusted odds ratio [OR], 1.15; 95% CI, 1.12-1.19) and female gender (adjusted OR, 1.91; 95% CI, 1.73-2.13) were associated with greater risk of persistence of long COVID; individuals with a graduate education vs high school or less (adjusted OR, 0.67; 95% CI, 0.56-0.79) and urban vs rural residence (adjusted OR, 0.74; 95% CI, 0.64-0.86) were less likely to report persistence of long COVID. Compared with ancestral COVID-19, infection during periods when the Epsilon variant (OR, 0.81; 95% CI, 0.69-0.95) or the Omicron variant (OR, 0.77; 95% CI, 0.64-0.92) predominated in the US was associated with diminished likelihood of long COVID. Completion of the primary vaccine series prior to acute illness was associated with diminished risk for long COVID (OR, 0.72; 95% CI, 0.60-0.86).Conclusions and RelevanceThis study suggests that long COVID is prevalent and associated with female gender and older age, while risk may be diminished by completion of primary vaccination series prior to infection.
Association of Vascular Risk Factors and Genetic Factors With Penetrance of Variants Causing Monogenic Stroke
Authors: Cho Bernard P. H. , Harshfield Eric L. , Al-Thani Maha , Tozer Daniel J. , Bell Steven , Markus Hugh S. 
Published: October 2022

ImportanceIt is uncertain whether typical variants causing monogenic stroke are associated with cerebrovascular disease in the general population and why the phenotype of these variants varies so widely.ObjectiveTo determine the frequency of pathogenic variants in the 3 most common monogenic cerebral small vessel diseases (cSVD) and their associations with prevalent and incident stroke and dementia.Design, Setting, and ParticipantsThis cohort study is a multicenter population-based study of data from UK Biobank participants recruited in 2006 through 2010, with the latest follow-up in September 2021. A total of 9.2 million individuals aged 40 to 69 years who lived in the United Kingdom were invited to join UK Biobank, of whom 5.5% participated in the baseline assessment. Participants eligible for our study (n = 454 756, excluding 48 569 with incomplete data) had whole-exome sequencing and available data pertaining to lacunar stroke-related diseases, namely stroke, dementia, migraine, and epilepsy.ExposuresNOTCH3, HTRA1, and COL4A1/2 pathogenic variants in monogenic stroke; Framingham cardiovascular risk; and ischemic stroke polygenic risk.Main Outcomes and MeasuresPrimary outcomes were prevalent and incident stroke and dementia. Odds ratios (ORs) and hazard ratios (HRs) were adjusted for age, sex, ethnicity, exome sequencing batch, and top 10 genetic principal components.ResultsOf the 454 756 participants (208 027 [45.8%] men; mean [SD] age, 56.5 [8.1] years), 973 participants carried NOTCH3 variants, 546 carried HTRA1 variants, and 336 carried COL4A1/2 variants. Variant carriers were at least 66% more likely to have had stroke. NOTCH3 carriers had increased vascular dementia risk (OR, 5.42; 95% CI, 3.11-8.74), HTRA1 carriers an increased all-cause dementia risk (OR, 2.17; 95% CI, 1.28-3.41), and COL4A1/2 carriers an increased intracerebral hemorrhage risk (OR, 3.56; 95% CI, 1.34-7.53). NOTCH3 variants were associated with incident ischemic stroke and vascular dementia. NOTCH3 and HTRA1 variants were associated with magnetic resonance imaging markers of cSVD. Cardiovascular risk burden was associated with increased stroke risk in NOTCH3 and HTRA1 carriers. Variant location was also associated with risk.Conclusions and RelevanceIn this cohort study, pathogenic variants associated with rare monogenic stroke were more common than expected in the general population and associated with stroke and dementia. Cardiovascular risk burden is associated with the penetrance of such variants. Our results support the hypothesis that cardiovascular risk factor control may improve disease prognosis in individuals with monogenic cSVD variants. This lays the foundation for future studies to evaluate the effect of early identification before symptom onset on mitigating stroke and dementia risk.
Association of Intraocular Pressure With Retinal Nerve Fiber Layer Thinning in Patients With Glaucoma
Authors: Nishida Takashi , Moghimi Sasan , Chang Aimee C. , Walker Evan , Liebmann Jeffrey M. , Fazio Massimo A. , Girkin Christopher A. , Zangwill Linda M. , Weinreb Robert N. 
Published: October 2022

ImportanceHigher intraocular pressure variability may be associated with faster structural changes in patients with glaucoma.ObjectivesTo investigate the association of mean intraocular pressure and intraocular pressure variability (defined as the SD of intraocular pressure and the intraocular pressure range) with the rate of retinal nerve fiber layer thinning over time in patients with glaucoma.Design, Setting, and ParticipantsIn this retrospective analysis of a longitudinal cohort, patients were enrolled from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation study. A total of 815 eyes (564 with perimetric glaucoma and 251 with preperimetric glaucoma) from 508 patients with imaging follow-up for a mean of 6.3 years from December 2008 to October 2020 were studied. Data were analyzed from November 2021 to March 2022.Main Outcomes and MeasuresIn this longitudinal study, eyes with at least 4 visits and 2 years of follow-up optical coherence tomography and intraocular pressure measurement were included. A linear mixed-effect model was used to investigate the association of intraocular pressure parameters with the rates of retinal nerve fiber layer thinning. Dominance analysis was performed to determine the relative importance of the intraocular pressure parameters.ResultsOf 508 included patients, 280 (55.1%) were female, 195 (38.4%) were African American, 24 (4.7%) were Asian, 281 (55.3%) were White, and 8 (1.6%) were another race or ethnicity; the mean (SD) age was 65.5 (11.0) years. The mean rate of retinal nerve fiber layer change was −0.67 (95% CI, −0.73 to −0.60) μm per year. In multivariable models adjusted for mean intraocular pressure and other confounding factors, faster annual rate of retinal nerve fiber layer thinning was associated with a higher SD of intraocular pressure (−0.20[ 95% CI, −0.26 to −0.15] μm per 1–mm Hg higher; P &amp;lt; .001) or higher intraocular pressure range (−0.05 [95% CI, −0.06 to −0.03] μm per 1–mm Hg higher; P &amp;lt; .001).Conclusions and RelevanceIn this study, intraocular pressure variability was independently associated with structural change in patients with glaucoma, even after adjustment for mean intraocular pressure, supporting its potential value in clinical management.
3D Human iPSC Blood Vessel Organoids as a Source of Flow‐Adaptive Vascular Cells for Creating a Human‐Relevant 3D‐Scaffold Based Macrovessel Model
Authors: Meijer Elana M. , Koch Suzanne E. , van Dijk Christian G.M. , Maas Renee G.C. , Chrifi Ihsan , Szymczyk Wojciech , Besseling Paul J. , Pomp Lisa , Koomen Vera J.C.H. , Buikema Jan Willem , Bouten Carlijn V.C. , Verhaar Marianne C. , Smits Anthal I.P.M. , Cheng Caroline 
Published: October 2022

Abstract3D‐scaffold based in vitro human tissue models accelerate disease studies and screening of pharmaceutics while improving the clinical translation of findings. Here is reported the use of human induced pluripotent stem cell (hiPSC)‐derived vascular organoid cells as a new cell source for the creation of an electrospun polycaprolactone‐bisurea (PCL‐BU) 3D‐scaffold‐based, perfused human macrovessel model. A separation protocol is developed to obtain monocultures of organoid‐derived endothelial cells (ODECs) and mural cells (ODMCs) from hiPSC vascular organoids. Shear stress responses of ODECs versus HUVECs and barrier function (by trans endothelial electrical resistance) are measured. PCL‐BU scaffolds are seeded with ODECs and ODMCs, and tissue organization and flow adaptation are evaluated in a perfused bioreactor system. ODECs and ODMCs harvested from vascular organoids can be cryopreserved and expanded without loss of cell purity and proliferative capacity. ODECs are shear stress responsive and establish a functional barrier that self‐restores after the thrombin challenge. Static bioreactor culture of ODECs/ODMCs seeded scaffolds results in a biomimetic vascular bi‐layer hierarchy, which is preserved under laminar flow similar to scaffolds seeded with primary vascular cells. HiPSC‐derived vascular organoids can be used as a source of functional, flow‐adaptive vascular cells for the creation of 3D‐scaffold based human macrovascular models.
Engineering Heart Valve Interfaces Using Melt Electrowriting: Biomimetic Design Strategies from Multi‐Modal Imaging
Authors: Vernon Michael J. , Lu Jason , Padman Benjamin , Lamb Christopher , Kent Ross , Mela Petra , Doyle Barry , Ihdayhid Abdul Rahman , Jansen Shirley , Dilley Rodney J. , De‐Juan‐Pardo Elena M. 
Published: October 2022

AbstractInterfaces within biological tissues not only connect different regions but also contribute to the overall functionality of the tissue. This is especially true in the case of the aortic heart valve. Here, melt electrowriting (MEW) is used to engineer complex, user‐defined, interfaces for heart valve scaffolds. First, a multi‐modal imaging investigation into the interfacial regions of the valve reveals differences in collagen orientation, density, and recruitment in previously unexplored regions including the commissure and inter‐leaflet triangle. Overlapping, suturing, and continuous printing methods for interfacing MEW scaffolds are then investigated for their morphological, tensile, and flexural properties, demonstrating the superior performance of continuous interfaces. G‐codes for MEW scaffolds with complex interfaces are designed and generated using a novel software and graphical user interface. Finally, a singular MEW scaffold for the interfacial region of the aortic heart valve is presented incorporating continuous interfaces, gradient porosities, variable layer numbers across regions, and tailored fiber orientations inspired by the collagen distribution and orientation from the multi‐modal imaging study. The scaffold exhibits similar yield strain, hysteresis, and relaxation behavior to porcine heart valves. This work demonstrates the ability of a bioinspired approach for MEW scaffold design to address the functional complexity of biological tissues.
Advances in the Translation of Electrochemical Hydrogel‐Based Sensors
Authors: Shafique Houda , de Vries Justin , Strauss Julia , Khorrami Jahromi Arash , Siavash Moakhar Roozbeh , Mahshid Sara 
Published: October 2022

AbstractNovel biomaterials for bio‐ and chemical sensing applications have gained considerable traction in the diagnostic community with rising trends of using biocompatible and lowly cytotoxic material. Hydrogel‐based electrochemical sensors have become a promising candidate for their swellable, nano‐/microporous, and aqueous 3D structures capable of immobilizing catalytic enzymes, electroactive species, whole cells, and complex tissue models, while maintaining tunable mechanical properties in wearable and implantable applications. With advances in highly controllable fabrication and processability of these novel biomaterials, the possibility of bio‐nanocomposite hydrogel‐based electrochemical sensing presents a paradigm shift in the development of biocompatible, “smart,” and sensitive health monitoring point‐of‐care devices. Here, recent advances in electrochemical hydrogels for the detection of biomarkers in vitro, in situ, and in vivo are briefly reviewed to demonstrate their applicability in ideal conditions, in complex cellular environments, and in live animal models, respectively, to provide a comprehensive assessment of whether these biomaterials are ready for point‐of‐care translation and biointegration. Sensors based on conductive and nonconductive polymers are presented, with highlights of nano‐/microstructured electrodes that provide enhanced sensitivity and selectivity in biocompatible matrices. An outlook on current challenges that shall be addressed for the realization of truly continuous real‐time sensing platforms is also presented.