6,498 research outputs found
The Spectroscopy and Molecular Dynamics of the High Frequency ν1 6 Intermolecular Vibrations in HCNâââHF and DCNâââDF
Gas phase rovibrational analysis of the high frequency intermolecular hydrogen bonded bending overtone 2ν0 6 [ν0=1132.4783(2) cmâ 1] in HCNâââHF and its corresponding perdeuterated fundamental ν1 6 [ν0=409.1660(2) cmâ 1] are reported. Evaluated rovibrational parameters provide the basis for quantitative modeling of the molecular dynamics associated with this vibration. A quantum mechanical calculation permits determination of the quadratic and quartic force constants K 6 6=537(17) and K 6 6 6 6=4.98(12) cmâ 1 which in turn are used to estimate the pertinent cubic band stretching interaction constants K 4 6 6=â149.3(50) cmâ 1 and account for the unexpected behavior in the rotational constantB 1 6. Second order expansion of the vibrational term energies, give X 4 6=â21.61(2), X 6 7=â7.694(1), X 6 6=â14.84(90), g 6 6=â31.04(90) cmâ 1, neglecting corrections for Fermi resonance. The common isotopic species equilibrium rotational constantB e is evaluated to be 3681.1(11) MHz
Incoherent Transport through Molecules on Silicon in the vicinity of a Dangling Bond
We theoretically study the effect of a localized unpaired dangling bond (DB)
on occupied molecular orbital conduction through a styrene molecule bonded to a
n++ H:Si(001)-(2x1) surface. For molecules relatively far from the DB, we find
good agreement with the reported experiment using a model that accounts for the
electrostatic contribution of the DB, provided we include some dephasing due to
low lying phonon modes. However, for molecules within 10 angstrom to the DB, we
have to include electronic contribution as well along with higher dephasing to
explain the transport features.Comment: 9 pages, 5 figure
Erratum: Determination of Dissociation Energies and Thermal Functions of Hydrogen Bond Formation Using High Resolution FTIR Spectroscopy [J. Chem. Phys. 8 7, 5674 (1987)]
Erratu
Extended Huckel theory for bandstructure, chemistry, and transport. II. Silicon
In this second paper, we develop transferable semi-empirical parameters for
the technologically important material, silicon, using Extended Huckel Theory
(EHT) to calculate its electronic structure. The EHT-parameters areoptimized to
experimental target values of the band dispersion of bulk-silicon. We obtain a
very good quantitative match to the bandstructure characteristics such as
bandedges and effective masses, which are competitive with the values obtained
within an orthogonal-tight binding model for silicon. The
transferability of the parameters is investigated applying them to different
physical and chemical environments by calculating the bandstructure of two
reconstructed surfaces with different orientations: Si(100) (2x1) and Si(111)
(2x1). The reproduced - and -surface bands agree in part
quantitatively with DFT-GW calculations and PES/IPES experiments demonstrating
their robustness to environmental changes. We further apply the silicon
parameters to describe the 1D band dispersion of a unrelaxed rectangular
silicon nanowire (SiNW) and demonstrate the EHT-approach of surface passivation
using hydrogen. Our EHT-parameters thus provide a quantitative model of
bulk-silicon and silicon-based materials such as contacts and surfaces, which
are essential ingredients towards a quantitative quantum transport simulation
through silicon-based heterostructures.Comment: 9 pages, 9 figure
Determination of Dissociation Energies and Thermal Functions of Hydrogenâbond Formation using High Resolution FTIR Spectroscopy
A technique which employs high resolution Fourier transform infrared spectroscopy is demonstrated for evaluation of hydrogen bonddissociation energiesD 0 and D e . Results for HCNââHF give a D 0=20.77(22) and D e =28.77(45) kJ/mol which are compared with previously determined values obtained from microwave absolute intensity measurements and a b i n i t i o molecular orbital calculations. Rovibrational band information available for HCNââHF also permits evaluation of thermal functions of dimer formation in kJ/mol: ÎU â 298.2 =20.1(2), ÎH â 298.2 =22.6(2), ÎG â 298.2 =59.4(2), ÎS â 298.2 =â0.1235
Comparison of Kansei Engineering and AttrakDiff to Evaluate Kitchen Products
Kansei Engineering can be used to create scales to measure perceptions and evaluations of products in a particular context. To what extent do specifically constructed Kansei scales reveal more information about a product than a more generic, prestructured instrument, such as AttrakDiff? This case study identified relevant affective and pragmatic Kansei attributes that influence the purchase of a range hood (cooker hood). 102 customers rated the extent to which each of 10 range hoods possessed these attributes. In addition, AttrakDiff was used to measure hedonic and pragmatic quality perceptions. There was a general high correspondence between AttrakDiff and Kansei. While Kansei provided richer and more specific feedback, it was more resource intensive to carry out
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Minimal breast milk transfer of rituximab, a monoclonal antibody used in neurological conditions.
ObjectiveTo determine the transfer of rituximab, an anti-CD20 monoclonal antibody widely used for neurologic conditions, into mature breast milk.MethodsBreast milk samples were collected from 9 women with MS who received rituximab 500 or 1,000 mg intravenous once or twice while breastfeeding from November 2017 to April 2019. Serial breast milk samples were collected before infusion and at 8 hours, 24 hours, 7 days, and 18-21 days after rituximab infusion in 4 patients. Five additional patients provided 1-2 samples at various times after rituximab infusion.ResultsThe median average rituximab concentration in mature breast milk was low at 0.063 Îźg/mL (range 0.046-0.097) in the 4 patients with serial breast milk collection, with an estimated median absolute infant dose of 0.0094 mg/kg/d and a relative infant dose (RID) of 0.08% (range 0.06%-0.10%). Most patients had a maximum concentration at 1-7 days after infusion. The maximum concentration occurred in a woman with a single breast milk sample and was 0.29 Îźg/mL at 11 days postinfusion, which corresponds with an estimated RID of 0.33%. Rituximab concentration in milk was virtually undetectable by 90 days postinfusion.ConclusionsWe determined minimal transfer of rituximab into mature breast milk. The RID for rituximab was less than 0.4% and well below theoretically acceptable levels of less than 10%. Low oral bioavailability would probably also limit the absorption of rituximab by the newborn. In women with serious autoimmune neurologic conditions, monoclonal antibody therapy may afford an acceptable benefit to risk ratio, supporting both maternal treatment and breastfeeding
UK Large-scale Wind Power Programme from 1970 to 1990: the Carmarthen Bay experiments and the Musgrove Vertical-Axis Turbines
This article describes the development of the Musgrove Vertical Axis Wind Turbine (VAWT)
concept, the UK âCarmarthen Bayâ wind turbine test programme, and UK governmentâs wind
power programme to 1990. One of the most significant developments in the story of British
wind power occurred during the 1970s, 1980s, and 1990s, with the development of the
Musgrove vertical axis wind turbine and its inclusion within the UK Governmentâs wind
turbine test programme. Evolving from a supervisorâs idea for an undergraduate project at
Reading University, the Musgrove VAWT was once seen as an able competitor to the
horizontal axis wind systems that were also being encouraged at the time by both the UK
government and the Central Electricity Generating Board, the then nationalised electricity
utility for England and Wales. During the 1980s and 1990s the most developed Musgrove
VAWT system, along with three other commercial turbine designs was tested at
Carmarthen Bay, South Wales as part of a national wind power test programme. From these
developmental tests, operational data was collected and lessons learnt, which were
incorporated into subsequent wind power operations.http://dx.doi.org/10.1260/03095240677860621
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