Intramolecular vibrational energy redistribution from a high frequency mode in the presence of an internal rotor: Classical thick-layer diffusion and quantum localization

We study the effect of an internal rotor on the classical and quantum intramolecular vibrational energy redistribution (IVR) dynamics of a model system with three degrees of freedom. The system is based on a Hamiltonian proposed by Martens and Reinhardt (J. Chem. Phys. {\bf 93}, 5621 (1990).) to study IVR in the excited electronic state of para-fluorotoluene. We explicitly construct the state space and show, confirming the mechanism proposed by Martens and Reinhardt, that an excited high frequency mode relaxes via diffusion along a thick layer of chaos created by the low frequency-rotor interactions. However, the corresponding quantum dynamics exhibits no appreciable relaxation of the high frequency mode. We attribute the quantum suppression of the classical thick-layer diffusion to the rotor selection rules and, possibly, dynamical localization effects.Comment: To appear in J. Chem. Phys. (August 28, 2007); 4 pages and 3 figure

Experimental Characterization Of Cu Free-Air Ball And Simulations Of Dielectric Fracture During Wire Bonding

Wire bonding is the process of forming electrical connection between the integrated circuit (IC) and its structural package. ICs made of material with low dielectric constant (low-k) and ultra low-k are porous in nature, and are prone to fracture induced failure during packaging process. In recent years, there is increasing interest in copper wire bond technology as an alternative to gold wire bond in microelectronic devices due to its superior electrical performance and low cost. Copper wires are also approximately 25% more conductive than Au wires aiding in better heat dissipation. At present, validated constitutive models for the strain rate and temperature dependent behavior of Cu free-air ball (FAB) appear to be largely missing in the literature. The lack of reliable constitutive models for the Cu FAB has hampered the modeling of the wire bonding process and the ability to assess risk of fracture in ultra low-k dielectric stacks. The challenge to FAB characterization is primarily due to the difficulty in performing mechanical tests on spherical FAB of micrometers in size. To address this challenge, compression tests are performed on FAB using custom-built microscale tester in the current study. Specifically, the tester has three closed-loop controlled linear stages with submicron resolution, a manual tilt stage, a six-axis load cell with sub-Newton load resolution for eliminating misalignment, a milliNewton resolution load cell for compression load measurement, a capacitance sensor to estimate sample deformation and to control the vertical stage in closed loop, a high working depth camera for viewing the sample deformation, and controllers for the stages implemented in the LabVIEW environment. FAB is compressed between tungsten carbide punches and a constitutive model is developed for Cu FAB through an inverse modeling procedure. In the inverse procedure, appropriate constitutive model parameter values are iterated through an automated optimization workflow, until the load-displacement response matches the experimentally observed response. Using the material properties obtained from the experiment, a macroscale finite element model for the impact and ulatrasonic vibration stages of wire bonding process is constructed to simulate (a) Plastic deformation of the Cu FAB at different time steps (b) Evolution of contact pressure (c) Phenomenon such as pad splash and lift-off. The deformations from the macroscale model are provided as input to a microscale model of the dielectric with copper vias as well as line-type heterogeneities. The microscale model is used to identify potential crack nucleation sites as well as the crack path within the ILD stack during wire bonding. The modeling provides insight into the relative amounts of damage accumulated during the impact and the ultrasonic excitation stages. In general, Bonding over Active Circuit (BOAC) has made wire bonding a considerable challenge due to the brittleness of the dielectric. Identifying and locating microscale fractures beneath the bond pads during wire bonding require extensive sample preparation and investigation for microscopic characterization. While simulations of fracture are an attractive alternative to trial and error microscopic characterization, the length scale of components involved in wire bonding varies from millimeters to nanometers. Therefore, constructing a finite element mesh across the model is computationally costly. Also, a multi-scale simulation framework is necessary. Such a modeling framework is also developed in this work to predict crack nucleation and propagation in wire bond induced failure

Pharmacokinetic profile of a new matrix-type transdermal delivery system: Diclofenac diethyl ammonium patch

A transdermal delivery system containing the anti-inflammatory analgesic diclofenac diethyl ammonium in an ethyl hexyl acrylate and vinyl acetate pressure-sensitive adhesive system was developed for percutaneous absorption. These patches were subjected to in vitro permeation and permeation enhancement studies through rat skin using a specially designed diffusion cell. Further, the work deals with peucutaneous absorption studies carried out on both animals and human volunteers. The pharmacokinetic parameters calculated from the blood levels of the drug reveal a profile typical of a sustained-release formulation, with the ability to maintain adequate plasma levels for 24 hr (i.e., up to the next application). (Area under the curve [AUC]: 4.356 +/- 1.3 mcg/ml.hr in animals and 0.442 +/- 0.053 mcg/ml.hr in humans; T-max was 8 hr in both the cases, whereas C-max was 0.288 +/- 0.088 mcg/ml in animals and 0.034 +/- .008 mcg/ml in human volunteers.) The amount of the drug bioavailable for targeting the sites of action is lower than via the oral route, but the absorbed dose appears to be adequate for therapeutic use, particularly because of the absence of side effects

The National Sentinel Caesarean Section Audit Report

This report presents the findings of the national audit of caesarean section rates in England, Wales and Northern Ireland. As the first national survey of its kind, this report provides information about the range and determinants of caesarean section rates with comparative data by countries, regions and maternity units, about demographic, clinical and organizational factors that may be influential, and about the views of women and obstetricians. This report provides an overview of the main results and a detailed description of the methodology

Give and take? The unexpected benefits of public engagement as an end-in-itself social practice in the Aberdeen Children of the 1950s cohort study

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Reducing low birth weight: prioritizing action to address modifiable risk factors

Background Low birth weight (LBW) affects 6.9% of all UK births and has remained largely unchanged for many years. The United Nations and theWorld Health Assembly have set targets to substantially reduce global incidence. Understanding the contribution of modifiable risk factors to the burden of LBW is required to ensure appropriate interventions are in place to achieve this reduction. Methods Data from published studies on the risks from key modifiable factors were used alongside prevalence data from theWelsh population to calculate the population attributable risk for each factor individually and in combination. Results Fourteen risk factors accounted for nearly half of LBW births, and 60% of those to younger mothers (,25 years). Tobacco smoke exposure was the largest contributor.We estimated that smoking in pregnancy was a factor in one in eight LBW births, increasing to one in five for women aged under 25. Conclusions Risk factors are interrelated and inequitably distributed within the population. Exposure to one factor increases the likelihood of exposure to a constellation of factors further increasing risk. Action to address LBW must consider groups where the risk factors are most prevalent and address these risk factors together using multi-component interventions

Mediators and Effect Modifiers of the Causal Pathway Between Child Exposure to Domestic Violence and Internalizing Behaviors Among Children and Adolescents : A Systematic Literature Review

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Caesarean section rates in England and Wales : investigating variation between maternity units

In England and Wales, the Caesarean section (CS) rate is 21.5%, ranging from 6% to 66% between maternity units. The impact of a high CS rate on women's health and NHS resources is not clear. Case-mix differences should be taken into account to enable valid comparisons and exploration of factors contributing to this variation. An understanding of these factors is important to ensure quality of obstetric care. The aim of this thesis was to explore the variation in CS rates between maternity units and evaluate the impact of (I) case-mix and (ii) women's birth preferences using National Sentinel Caesarean Section Audit (NSCSA) data. Summary of NSCSA data: Phase 1 (01.05.2000 to 31.07.2000) • Information on 150,139 women giving birth in 216 maternity units in England and Wales. Variables collected include age, ethnicity, parity, number of previous CS, mode of onset of labour, gestation, presentation, mode of delivery and birth weight. Phase 2 (01.12.2000 to 31 .01 .2001) • Survey of 2,475 pregnant women from 40 selected maternity units. Variables include preferred type of birth. Case-mix data were also collected for all 32,536 women giving birth in these maternity units. The relationship between case-mix variables and CS (i) before labour and (ii) during labour was demonstrated using logistic regression. Using tese results, standardised CS rates were calculated for individual maternity units. Using meta-analytical techniques, the amount of variation in CS rates explained by case-mix adjustment was quantified. Data on preferred type of birth were available for 7% of women in Phase 2. Therefore various techniques for handling 'missing data' including multiple imputations were researched and applied to these data. Key findings: . The association between CS and case-mix variables vary for CS before labour and CS during labour. The odds of CS (before and in labour) increase with maternal age. Women from ethnic minority groups have lower odds of CS before labour, and increased odds of CS in labour. Women with a previous vaginal delivery have lower odds of CS, although the magnitude of this for CS before and in labour is markedly different. . Adjustment for case-mix explained 34% of the variance in CS rates between maternity units. • Adjustment for case-mix differences and women's birth preferences explained 45% of the variance in CS rates between maternity units in England and Wales. 3EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The causal web of foetal alcohol spectrum disorders : a review and causal diagram

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Hospital admissions in infants with Down syndrome : a record-linked population-based cohort study in Wales

Acknowlegements This research was supported by The Centre for the Development and Evaluation of Complex Interventions for Public Health Improvement (DECIPHer), a UK Clinical Research Collaboration Public Health Research Centre of Excellence, and The Centre for the Improvement of Population Health through E-records Research (CIPHER). CIPHER was funded by: Arthritis Research UK, the British Heart Foundation, Cancer Research UK, the Chief Scientist Office (Scottish Government Health Directorates), the Economic and Social Research Council, the Engineering and Physical Sciences Research Council, the Medical Research Council, the National Institute for Health Research, the National Institute for Social Care and Health Research (Welsh Government), and the Wellcome Trust (Grant reference: MR/K006525/1). The development of the Wales Electronic Cohort for Children (WECC) was supported by a Translational Health Research Platform Award from the National Institute for Social Care and Health Research (grant reference: TPR08-006).Peer reviewedPublisher PD