bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Temperature Compensation Method for a MEMS Gyroscope Oriented on a Periphery Circuit
Authors: Cao Huiliang , Li Hongsheng , Sheng Xia , Wang Shourong , Yang Bo , Huang Libin
Published: September 2013

This paper investigates temperature compensation methods used for the scale factor and bias of the MEMS gyroscope within the temperature range from − 40°C to 60°C. The structure and periphery monitor circuit are introduced. Then the determinant elements of the MEMS gyroscope's scale factor are analysed and the results indicate that scale factor is directly proportional to drive amplitude and sense loop gain and is inversely proportional to the frequency gap between two modes. After that, the compensation methods are proposed, the thermal resistor's positive temperature coefficient (tempco) is utilized to calibrate the scale factor's tempco through regulating the drive mode amplitude and the sense loop gain, and each method is applied respectively and the results are contrasted. The test results of the two specimens express that the most effective compensation method could decrease the scale factor's tempco from 693ppm/°C (640ppm/°C) to 250ppm/°C (257ppm/°C), improving it by 63.9% (59.8%). Finally, a method of declining bias's tempco is investigated and implemented after scale factor compensation. A summator with a thermal resistor is utilized at the output level and decreases the bias's tempco from 103.89°/h/°C (100.78°/h/°C) to 9.70°/h/°C (12°/h/°C) improving it by 90.7% (88%). Repeat tests are performed based on two specimens to prove the repeatability and reproducibility of the methods.
How is a Service Development Simulation Exercise Useful? A Student-Centered Perspective
Authors: Spiteri Damian
Published: September 2013

This paper appraises a simulation activity which forms part of the post-graduate social work curriculum offered at the University of Strathclyde. It shows how simulations that are based on activities that are as close as possible to actual ‘real-life’ situations can be applied as a teaching strategy so as to enable students to integrate knowledge, skills and critical thinking in the social work field. It presents the students' appraisal of the module and aims to generate insights about its suitability for application to a wide range of training courses, including those of education, health, social care and any of the applied social sciences. The study was undertaken by observing and interacting with the students while they set and completed relevant tasks and by extrapolating relevant data from the ‘evaluation sheets’ that they filled in at the end of the module. The paper shows that the students were introduced to perspectives of the subject matter that they had not thought about previously. It also provided them with an opportunity to apply theory to a practice situation in a manner that further consolidated their overall social work training.
Attitudes towards and Effects of the Use of Video Games in Classroom Learning with Specific Reference to Literacy Attainment
Authors: Mifsud Charles L. , Vella Rosalind , Camilleri Liberato
Published: September 2013

The first part of this study shows that there is increased support for using video games in the classroom from different stakeholders, namely students, teachers and parents. The potential role that video games can play in the classroom learning process needs to be more well defined. There is a dire need for research work under experimental conditions which measures tangibly the effectiveness of videogame use in classroom learning. The experimental study described here seeks to address this need and focuses on the very important area of literacy attainment. The Experimental Group of students which used the videogame in the classroom obtained significant gains on a number of English as a Second Language items when compared to the other group of students which followed their regular programme. This study makes a claim for teachers to be supported in their endeavours to harness video games as a teaching and learning tool. However, the role of teachers in this process requires redefinition. It calls also for the concerns of teachers to be addressed if they are to feel they can play a significant role in the adoption of video games in classroom learning.
Family Socioeconomic Status, Parent Expectations, and a Child's Achievement
Authors: Stull Judith C.
Published: September 2013

This study investigates how a family's socioeconomic status (SES) affects a child's educational achievement and differentiates the direct effects of SES on these experiences from the indirect ones as they are mediated by the school. This distinction is an important one as it is in the latter realm where social policy can have an impact. The data are from a nationally representative sample of children enrolled in kindergarten in the US in the Spring of 2000. The percentage of the parents expecting their child to earn at least a Bachelor's degree rises with family SES. However, the percentage of high-SES parents of low-achieving students expecting their child to earn at least a Bachelor's degree is higher than that for low- and middle-SES parents of high-achieving students. Ordinary least squares regression analyses using a mediation model were used to distinguish direct from indirect effects of the family's SES score on achievement. Unexpectedly, the direct effects are greater than the indirect ones.
Gender Differences in Saving and Spending Behaviours of Thai Students
Authors: Sereetrakul Wilailuk , Wongveeravuti Siriwan , Likitapiwat Tanakorn
Published: September 2013

Since males and females are raised differently by their parents (Thorne, 2003), gender roles may affect the saving and spending behaviours of male and female teenagers. The objective of this research was to study the gender differences in saving and spending behaviours of Thai students. This was an exploratory study where a questionnaire was used to collect information from four hundred and fifty-five students. The data were analysed using a Fisher exact test and a t-test for two independent samples. The results showed that female and male students did not have different saving behaviour, although females had a more positive attitude towards saving and shopping than males. In addition, females were more concerned about being rich or having a lot of money than males, while males had a more positive attitude towards spending money than females. The study also revealed that female and male students bought different types of products.
Analyzing the Gender Gap in Math Achievement: Evidence from a Large-Scale US Sample
Authors: Cheema Jehanzeb R. , Galluzzo Gary
Published: September 2013

The US portion of the Program for International Student Assessment (PISA) 2003 student questionnaire comprising of 4,733 observations was used in a multiple regression framework to predict math achievement from demographic variables, such as gender, race, and socioeconomic status, and two student-specific measures of perception, math anxiety and math self-efficacy, while controlling for age, psychological disability, and language proficiency. The results confirmed the existence of persistent racial and socioeconomic gaps in math achievement, showed that both anxiety and self-efficacy contribute significantly towards explaining variation in math achievement, and provided evidence that the gender gap disappears once important predictors of math achievement, such as math-specific self-efficacy and anxiety, are controlled for.
Vascular Endothelial Growth Factors: Pharmacological aspects and applications in ophthalmic practices
Authors: Dubey Ashok K , Biswas N R , Das G K
Published: September 2013

Vascular endothelial growth factor (VEGF) plays a critical role in initiating a cascade of reactions important for the normal as well as abnormal angiogenesis. Many of the serious retinal and other ocular disorders are associated with neovascularization and increased capillary permeability. VEGF has been seen to play a major role in the pathogenesis of neovascular age related macular degeneration (AMD), diabetic retinopathy, macular edema, retinal vein occlusion, retinopathy of prematurity, neovascular glaucoma and other ocular conditions due to neovascularization and increased vascular permeability. Produced by many cells in the eye, VEGF is mainly stimulated by hypoxia and initiates angiogenesis by promoting the mitosis of vascular endothelial cells. It causes the release of nitric oxide from the vascular endothelial cells resulting in vasodilatation. VEGF has hematopoietic effects facilitates monocyte chemotaxis and acts as a survival factor for the endothelial cells. It also breaks down the blood-retinal barrier increasing the capillary permeability. After the introduction of anti-angiogeinic drugs, there has been a paradigm shift in the treatment of neovascular ocular diseases. Anti-VEGF drugs such as pegaptanib, ranbizumab, bevacizumab and aflibercept have helped in the management of many such disorders. Currently VEGF is one of the most pursued research molecule in ophthalmology and the concerns related to the dosing frequency, the duration of treatment, long term safety and cost of its inhibitors will hopefully be further addressed in the near future with more definite insights about the molecule and the related drugs.
Effect of Glaucoma Filtering Surgery on Advanced Visual Fields
Authors: Gupta Vinay , Chaudhary Kulbhushan P. , Sharma Vinod , Thakur Pankaj , Singh Balraj
Published: September 2013

Purpose:

To evaluate the effect of glaucoma filtering surgery on advanced visual fields.

Materials and Methods:

We conducted a cohort study of 17 cases of glaucoma with advanced visual field defects and performed trabeculectomy or its modification. We followed this cohort and reviewed their Intraocular pressure (IOP) & visual fields preoperatively and then postoperatively on days seven, six weeks, three & six months.

Results:

The mean IOP after six months of follow up dropped to 14.12 ± 1.50 mmHg (range 6 to 16) (p=0.001) from preoperative level of 45.77 ± 16.38 mmHg. Visual fields improved in four (23.5%) cases, stabilized in eight (47.1%) and deteriorated in five cases (29.4%). The preoperative Average Mean Meridian of 12.13. ± 8.84 (range 4.29 to 40.83) increased to 12.58± 7.48 (range 2.08 to 22.92) at six month follow up and no wipeout phenomenon was observed

Conclusions:

Glaucoma filtering surgery has a beneficial effect in the vast majority of patients with advanced visual field defects and elevated IOP. Wipeout phenomenon was observed in none.
Glued Endocapsular Hemi-Ring Segment for Sutureless Trans-Scleral Fixation of the Capsular Bag and Its Contents
Authors: Jacob Soosan , Agarwal Amar , Agarwal Athiya
Published: September 2013

The glued endocapsular ring, designed by the author (SJ), is a new device aimed at fibrin glue assisted sutureless trans-scleral fixation of a subluxated cataract/ IOL. This eliminates suture related complications while providing better stability of the bag intra-operatively as well as in the long term post-operatively. This device allows easier surgery and avoids cumbersome, complicated needle passes through the anterior chamber. Intra-operative adjustment and if required, readjustment of IOL centration is possible and easy unlike sutured rings and segments. The fibrin glue allows a hermetic seal of the flap over the exteriorized haptic. The device is made of PVDF and is available as hemi-ring as well as smaller segments.
Primary Optic Atrophy in Osteopetrosis
Authors: Dedhia Chintan , Parekh Nilesh , Gohil Neepa , Patel Hetal , Parmar Yogesh
Published: September 2013

Osteopetrosis is a rare disorder of defective osteoclastic resorption of bone, resulting in abnormally dense bones. Two main forms are milder adult onset autosomal dominant form and severe infantile malignant autosomal recessive form. Both types of mutations lead to disturbances of acidification needed for normal osteoclast function. We report a rare ocular finding in a rare case of malignant variety of osteopetrosis. A five month old girl child diagnosed as malignant variety of osteopetrosis with failure to thrive on fundus examination revealed chalky white optic discs with sharply demarcated borders bilaterally. Cranial neuropathies are caused due to improper bone remodeling leading to narrowing o] cranial nerve foramina and compression of nerves in skull foramina. Allogeneic hematopoietic stem cell transplantation is the only treatment known to significantly alter the course of disease.
Spectrum of features of Gronblad-Stradberg Syndrome
Authors: Gupta Malvika , Vohra Vishal , Bajaj Sonali , Malik Praveen Kumar , Ahuja Arvind
Published: September 2013

Pseudoxanthoma elasticum (PXE) with ocular and cutaneous features, also known as Grönblad-Strandberg syndrome, is a rare inherited disorder associated with mutations in the ABCC6 gene. PXE most commonly involves the elastic fibers of the mid and deep reticular dermis of skin, the Bruch membrane of the eye, and the blood vessels. Almost all patients with PXE have ocular involvement; with characteristic angioid streaks being seen in 85 % of the patients. The streaks represent cracks and fissures in the calcified Bruch's membrane. This ocular change is generally bilateral and is often noted several years after the onset of cutaneous lesions. Prime cause of vision loss is development of macular choroidal neovascularisation (CNV). Patients with PXE typically have a normal life span, with mortality and morbidity largely due to extracutaneous manifestations like central vision loss, gastrointestinal haemorrhage and cardiovascular manifestations, such as angina and hypertension in later stages of the disease spectrum. Authors describe a classic case with typical ocular manifestations of angioid streaks and fine-yellow drusen like pigment irregularities at macula along with distinctive yellow plaques in the flexural areas of the body; posterolateral area of neck, antecubital fossa of arms, chest and thighs. Skin biopsy was done which confirmed the diagnosis
Molecular Evolution: Rates
Authors: Bromham Lindell
Published: September 2013

The rate of molecular evolution varies dramatically between taxa, for example, some viruses have a rate of genome evolution a million times faster than mammals. Although some rate variation may be due to random fluctuations or locus‐specific effects, studies have revealed strong and predictable patterns in the differences in the rate of molecular evolution between species. In particular, large, long‐lived organisms with low reproductive output tend to have slower rates of molecular evolution than related species with shorter lives, faster generations or higher fecundity. Studies of the variation in the rate of molecular evolution between species may reveal the mechansims underlying these differences, and can inform analyses that seek to derive information on evolutionary history and processes from molecular data.

Key Concepts:

The number of genetic differences between lineages increases with the time since their separation, but differences do not accrue in the same rate in all lineages.

Variation in the rate of molecular evolution can be compared between species by comparing absolute rates, derived from laboratory experiments or estimated by comparing sequences where the age of the divergence is known.

A more common approach is to compare the relative rate differences between species by comparing the number of sequence changes that have accumulated since they last shared a common ancestor.

Mutation rate varies between species, at least in part due to the action of selection finding a balance between the competing costs of DNA repair and mutation.

Many mutations arise from DNA replication errors, so the more times DNA is copied per unit time, the higher the mutation rate will be.

Rates of molecular evolution in many taxa scale with body size, possibly because smaller‐bodied taxa go through more genome replications per unit time, a hypothesis referred to as the generation time effect.

Metabolic rate has been suggested to play a role in species differences in mutation rate, on the assumption that species with higher mass‐specific metabolic rate will suffer more DNA damage per unit time, though there is little direct evidence for this hypothesis.

Natural selection might play a role in fine‐tuning mutation rates to fit different life history strategies, for example, reducing mutation rates in large, long‐lived organisms.
Control of Plant Organ Size
Authors: Egea‐Cortines Marcos , Weiss Julia
Published: September 2013

Lateral aerial organs are produced from the primordia initiated in the shoot apical meristem. Early stages of lateral organ growth require cell division and a sharp transition occurs late in development towards a cell expansion‐based growth. A current hypothesis indicates that cytokinin signalling in meristematic cells is downregulated to allow differentiation. Increased local auxin levels promoting growth accompany this event. The later stage coincides with jasmonic acid signalling required for flower maturarion. Within one organism, lateral organs of the same type can change in size and shape during ontogeny, a feature called heteroblasty. The developmental programme leading to final organ size may be modulated by environmental cues including photoperiod, temperature and abiotic stress. These environmental signals are integrated into the morphogenetic programme allowing better adaptation as a result of developmental plasticity.

Key Concepts:

Initial growth of lateral organs requires the downregulation of cytokinins allowing morphogenesis and differentiation.

Early developmental stages are characterised by cell division, whereas later stages show a rapid transition to growth caused by cell expansion.

There seems to be a compensation mechanism at the organ size level allowing increased cell expansion when cell division is compromised and vice versa, giving as a result lower organ size variation.

A given species may develop lateral organs differing in size and shape during development, a phenomenon called heteroblasty. A coordination between a basic growth programme and the timing of organ formation seems to be responsible for this phenomenon.

Plant organ size is the result of an underlying genetic programme and the interaction with environmental conditions that fine tune the final size of an organ.
Comparing the Human and Fish Genomes
Authors: Nakatani Yoichiro , Qu Wei , Morishita Shinichi
Published: September 2013

Comparing human and fish genomes has been proven useful to understand vertebrate evolution. To demonstrate this, two major questions and related findings are addressed here. In 1970, based on limited observations, Ohno postulated that whole genome duplication events took place in early vertebrates and were essential to increasing complexity of vertebrates over the past 600 My. For providing conclusive support to Ohno's hypothesis, comparative genomics of the fish and human genomes was indispensable. Another question is whether
deoxyribonucleic acid (DNA)
sequence variation might reflect germ line genetic activity, underlying chromatin structure and DNA methylation. Analysis of the medaka fish and human genomes uncovered two important properties. Nucleosome positioning is correlated with periodic sequence variation downstream of transcription start sites in germ line cells, and genome‐wide genetic variations are highly correlated with proximal DNA methylation patterns. These findings suggest the potential for genetic activity (transcription), chromatin structure and DNA methylation to contribute to moudling the DNA sequence on an evolutionary timescale.

Key Concepts:

In 1970, based on limited observations, Ohno postulated that whole genome duplication events took place in early vertebrates and were essential to increasing complexity of vertebrates over the past 600 My.

Comparative genomics of the fish and human genomes was indispensable to provide conclusive support to Ohno's hypothesis.

Nucleosome positioning is correlated with periodic sequence variation downstream of transcription start sites in germ line cells.

Genome‐wide genetic variations are highly correlated with proximal DNA methylation patterns.

Nakatani
et al.
suggest a contrast between the slow karyotype evolution after the second WGD and the rapid, lineage‐specific genome reorganisations that occurred in the ancestral lineages of major taxonomic groups such as teleost fishes, amphibians, reptiles, and marsupials.
Lipoxygenase Pathway of the Arachidonate Cascade
Authors: Kobe Matthew J , Newcomer Marcia E
Published: September 2013

Lipoxygenases (LOXs) are iron‐containing enzymes that catalyse the peroxidation of polyunsaturated fatty acids. In mammals, LOX products and their metabolites are potent lipid mediators that provoke diverse biological responses. These eicosanoids, derived from arachidonic acid, play important roles in inflammation and the resolution of inflammation. Moreover, they have been implicated in the development of cardiovascular disease. Although several LOX isoforms are expressed in individual organisms, each generates a specific product. How structurally and mechanistically related enzymes generate different products from a common substrate is not fully understood. In addition, the biological effects of many of the lipid mediators produced through LOX pathways remain to be uncovered.

Key Concepts:

Arachidonic acid is a substrate for lipoxygenases, iron enzymes that catalyse the peroxidation of polyunsaturated fatty acids.

Mammalian lipoxygenases transform the common substrate (arachidonic acid) to a unique stereo‐ and regiospecific product.

Leukotriene synthesis is initiated by 5‐lipoxygenase.

Lipoxygenase products and their downstream metabolites are potent signalling molecules, some of which play roles in inflammation or its resolution.

Lipoxygenase products are associated with cardiovascular diseases, but their molecular mechanism of action remains unclear.
Genetics of Anorexia Nervosa
Authors: Baker Jessica H , Trace Sara E , Janson Lauren E , Bulik Cynthia M
Published: September 2013

Anorexia nervosa (AN) is a heritable disorder characterised by an extremely low body weight and food restriction that frequently onsets during adolescence. However, AN is observed across the lifespan. A majority of twin studies reveal that genetic factors, on average, account for between 40% and 60% of the liability to AN. Candidate gene studies exploring the molecular genetic basis of AN have primarily focussed on genes in the serotoninergic and dopaminergic pathways. Although no pathway or gene has been unequivocally demonstrated to play a causal role in AN,
5‐HTTLPR
,
5HT2A
,
DRD2
and
DRD4
are noteworthy candidates from the serotonin and dopamine systems. Genome‐wide association studies have not yet revealed any genes meeting genome‐wide significance for AN. However, sample sizes have been small and underpowered, underscoring the need for much larger samples.

Key Concepts:

Anorexia nervosa is, on average, estimated to be 40–60% heritable.

Chromosome 1 has received some support for harbouring a region of interest for AN.

Candidate gene studies of AN have provided inconclusive results.

Genes in the serotonin, dopamine and opioid systems have shown some positive associations with AN.

Genome‐wide association studies have not revealed significant findings for AN, although they have been underpowered.

The genetic architecture of AN is likely complex, representing a synergistic interaction between many genetic and environmental factors.
Hyphenated Methods for Speciation Analysis
Authors: Michalski Rajmund , Jabłońska‐Czapla Magdalena , Łyko Aleksandra , Szopa Sebastian
Published: September 2013

Speciation analysis, understood as research into various element forms, is gaining importance in environmental protection, biochemistry, geology, medicine, pharmacy, and food quality control. It is popular because what frequently determines the toxicological properties of a compound or element is not its total content. In many cases, it is the presence of its various forms. Studying low analyte concentrations, particularly in complex matrix samples, requires meticulous and sophisticated analytical techniques. The latest trends embrace the so‐called hyphenated methods, which combine different separation and detection methods. The following article describes the role and importance of hyphenated methods in speciation analyses of selected elements.
Cognitive Restructuring
Authors: Clark David A.
Published: September 2013

Cognitive restructuring is the core therapeutic ingredient of cognitive therapy that was first introduced to the psychotherapy community by A. T. Beck and colleagues. This chapter provides a detailed breakdown and elaboration of cognitive restructuring and how it is implemented to effect symptom change. The nature of cognitive restructuring and its multifaceted therapeutic components are discussed. A critical review of the empirical research on its treatment efficacy is presented, as well as the evidence for cognitive mediation from component and mediation process research. It is concluded that cognitive restructuring is an effective treatment strategy for psychological disorders, especially anxiety and depression. However, superiority to other “less cognitive” interventions has not been demonstrated, even though the effectiveness of cognitive restructuring does occur by inducing cognitive change. Various research issues are raised that would advance a greater understanding of the mechanisms of change associated with cognitive restructuring. With greater knowledge of the change processes that characterize cognitive restructuring, clinicians will be better equipped to employ this powerful therapeutic intervention.
Molecular Spectroscopy and Molecular Dynamics: Theory and Experiment
Authors: Quack Martin , Kutzelnigg Werner
Published: September 2013

Current aspects of the field of research are summarized, as defined by the title of this article and the theme of the related, recent discussion meeting, which is the subject of this special issue of Berichte der Bunsengesellschaft für Physikalische Chemie.
A. Experiment and Theory of High Resolution Spectra of Rovibronic Molecular States. Improved Theoretical 1Σu+ and 1Πu Wavefunctions, Energies, and Transition Moments for the H2 Molecule
Authors: Dressler K. , Wolniewicz L.
Published: September 2013

In the emission spectrum of molecular hydrogen the Rydberg‐Rydberg bands of type nsσg−2pσu,πu are an order of magnitude weaker than the corresponding bands with ndσg upper states. We have calculated the dipole moment functions for the electronic 1Σg+ − 1Σu+ and 1Σg+ ‐ 1Πu transitions whose upper states at small inter‐nuclear distances are of 2s, 3s, 3dσ, 4s, and 4dσ character, with lower states 2pσB, 3pσ B', 4pσ B” 1Σu+, 2pπ C, and 3pπ D 1Πu. The results confirm that the transitions of s–p character are much weaker than the d‐p ones. We have also obtained improved Born‐Oppenheimer electronic energy curves and adiabatic energy corrections for the lowest four 1Σu+ and two 1Πu states, and nonadiabatic coupling functions among the four 1Σu+ states. In the B 1Σu+ state the theoretical term values of the lowest rovibronic levels agree, after correction for nonadiabatic and relativistic energy shifts, with spectroscopic measurements in H2 and D2 within the combined uncertainties of the experiments and of the small, unknown radiative energy corrections.
Dipole Moment Function of Methane and Analytical Anharmonic, 9‐dimensional Potential Surface: Theory and Experiment for the Permanent Electric Dipole Moment of CH2D2 Using Quantum Monte Carlo Calculations and FIR Spectroscopy
Authors: Hollenstein Hans , Marquardt Roberto R. , Quack Martin , Suhm Martin A.
Published: September 2013

The pure rotational spectrum in the far‐infrared and its absolute intensity in the vibrational ground state of CH2D2 and CHD3 were measured by high‐resolution interferometric Fourier transform techniques. The analysis of the integrated absorption cross sections results in a permanent, vibrationally induced electric dipole moment |μ0| = (8.6 ± 1.4)·10−3 Debye for CH2D2. This value is much more reliable than the older value existing in the literature and is also in much better agreement with our previously published theoretical estimate (μ0 = ‐(7.60±0.50)·10−3 Debye, the z‐axis being the C2 axis with sign chosen such that the H‐atoms have positive z‐coordinates).
The Vibrational Spectrum of Fluorochloroethyne FCCC1: Ab Initio Calculations and High Resolution Infrared Studies
Authors: Breidung J. , Bürger H. , Senzlober M. , Thiel W.
Published: September 2013

The FCCC1 molecule has been studied by ab initio methods and high resolution IR spectroscopy. Employing a TZ2Pf basis set the quadratic, cubic, and quartic force fields have been determined at the SCF and MP2 levels, and the equilibrium structure has been calculated. The vibrational and rovibrational parameters deduced from the force fields have guided the analysis of high resolution FTIR spectra of FCCC1 in the v1, v2, 2v4 and v4 v5 regions. Therefrom, ground, v4 = 1 and v5 = 1 rotational parameters have been determined by means of lower state combination differences. The 2v4 (Σ+) and v4v5 (Σ+ and Δ) levels have been analyzed in detail, and anharmonic perturbations disclosed with the help of the ab initio results. The available experimental data are in excellent agreement with the ab initio predictions.
C. Spectroscopy of Excited States, Kinetics and Photodissociation. Fine Structure and Hyperfine Structure Effects in Unimolecular and Complex‐Forming Bimolecular Reactions
Authors: Troe J.
Published: September 2013

Fine structure and hyperfine structure effects can influence the kinetics of unimolecular and complex‐forming bimolecular reactions. The corresponding energetic effects are analyzed in the framework of the statistical adiabatic channel model (SACM). The reactions O+OH → O2 + H, OH + CO → H + CO2, C+ + OH → products, C+ + NO → products, and NO2 → O + NO serve as examples.
Vibration to Electronic Energy Transfer in Carbon Monoxide between X1Σ and a3Π
Authors: Schulz O. , Lin J. X. , Urban W.
Published: September 2013

A careful analysis of experimental data for a CO laser plasma shows a considerable depletion of the vibrational distribution of the electronic ground state in the energy range of the first excited electronic state a3Π. If the transferred population would reappear completely, the corresponding concentration of CO in the a3Π state should be observable by the most sensitive Faraday laser magnetic resonance technique. From the fact that no signal could be found, we deduce an upper concentration for CO a3Π which is then compared to a new refined model. This model takes into account both VE transfer rates between the ground state and the a3Π and a relaxation rate for the triplet state.
Vibrational IR‐Multiphoton Excitation of Thiirane‐1‐oxide (C2H4SO) and d‐Thiirane‐1‐oxide (C2H3DSO)
Authors: Gross Heike , He Yabai , Jeitziner Christian , Quack Martin , Seyfang Georg
Published: September 2013

We report the IR‐laser‐induced dissociation of C2H4SO and of C2H3DSO, which was synthesized for the first time. After multiphoton excitation in the frequency range of the SO chromophore (with a large band strength of G = 2.4 pm2 for C2H4SO and 2.8 pm2 for C2H3DSO) in the 1060‐1090 cm−1 range of the CO2 laser the product analysis was carried out by static yield measurements using quantitative IR‐spectroscopy of ethylene (C2H3D, C2H4). Effective laser chemical rate constants k1(st) = (0.70±0.38) cm2 J−1 for C2H3DSO with excitation at v̄(R28) = 1083.48 cm−1 and (0.52±0.14) cm2 J−1 for C2H4SO were obtained from a fit to the fluence dependence of the photochemical primary yields. A nonlinear intensity dependence of the apparent product yield (Papp) was found by using different temporal pulse profiles (singlemode, mode‐locked and multimode pulses) at 1083.48 cm−1 (9R28) for C2H4SO and at 1082.30 cm−1 (9R26) for C2H3DSO in static yield measurements and time‐resolved experiments. FTIR measurements were performed to assign the fundamentals of C2H3DSO, which are compared with the harmonic frequencies calculated using GAUSSIAN 92 at MP2 level with different basis sets.
Ultrafast Collisional Redistribution of Vibrational Energy in Highly Excited Polyatomic Molecules. The Role of Intramolecular Interactions
Authors: Kosterev A. A. , Malinovsky A. L. , Tretyak S. A. , Ryabov E. A.
Published: September 2013

Time‐resolved Raman probing technique is used to investigate the collisional relaxation of high‐lying C‐H vibrations in CHF3 and CHF2Cl molecules. The relaxation rates both in collisions with parent molecules and a number of buffer gases were measured. The rate values were found to be abnormally fast. The relaxation is faster than single collision in parent gas and requires a few (3‐8) collisions for nonpolar gases. For polar gases the relaxation is still faster.

The conclusion is made that observed ultrafast relaxation of C–H modes is caused by energy transfer from excited “bright” states to nearby “dark” ones. Possible mechanisms of the above transfer are discussed.
Photodissociation of the HCO+ Ion
Authors: Koch A. , van Dishoeck Ewine F. , van Hemert M. C.
Published: September 2013

Ab initio MRD‐CI calculations are presented for the photodissociation of the HCO+ ion, which plays an important role in the chemistry in interstellar space and in combustion flames. One‐dimensional potential energy curves along the C‐H bond length coordinate are presented for the lowest eight electronic singlet states. The calculations show that the 11Π state is the lowest excited state through which dissociation is possible and which can be reached by dipole‐allowed transitions. The photodissociation dynamics on the 11Π potential and through the higher‐lying 2 and 31Σ+ states are studied in the one‐dimensional approximation, using a time‐independent quantum mechanical treatment. The geometry dependence of the electric dipole transition moment is taken into account.
D. New Experimental Methods and Applications. Applications of Fluorescence Demodulation Spectroscopy (FDS)
Authors: Klein Uwe K. A.
Published: September 2013

Some possibilities of fluorescence demodulation spectroscopy (FDS) are discussed. These include the application to decay in the nanosecond to picosecond range and to transitions in spectra with a resolution of less than the Doppler width, i.e. to high‐resolution spectroscopy. Also, a variation of FDS, i.e. demodulation spectroscopy (DS) for use in femtosecond ‐ kinetics, allowing the investigation of ultrashort‐lived transition states, is being discussed.
Recent Advances in Rovibrationally Resolved FTIR Supersonic Jet Spectroscopy of Transients, Weakly Bound Dimers and Trimers
Authors: Hartz C. L. , Wofford B. A. , McIntosh A. L. , Meads R. F. , Lucchese R. R. , Bevan J. W.
Published: September 2013

Recent advances in the development and application of a highly sensitive near infrared FTIR supersonic jet spectrometer are reported. Investigations of: v1 OC‐HF; ν1, ν2 OC‐HCl; ν1 +, ν2 ± (HCl)2; ν1, ν1±ν21 Ar‐HCl and ν1 N2‐HCl will be presented. In specific cases, a direct comparison with corresponding spectra recorded using tunable near infrared laser supersonic jet and molecular beam absorption spectrometers will be made to illustrate the current capabilities and limitations of the FTIR supersonic jet spectrometer. As an example of the application of the technique to clusters, we report a study of the ν5 HCl asymmetric stretching band in the trimer, (HCl)3. Some preliminary studies of discharge‐generated species will also be reported using the jet spectrometer. The latter include: i) the investigation of vibrational hot bands in CO and ii) A2Π3/2,1/2→X2Σ+ rovibronic transitions in the CN radical.
Ab Initio Calculations of the Binding Energies of Small (H2O)n Clusters (n = 1…4)
Authors: Klopper Wim , Schütz Martin
Published: September 2013

The binding energies of the water dimer, trimer, and tetramer were calculated employing coupled‐cluster theory with singles, doubles, and non‐iterative triples (CCSD(TT)), and Møller‐Plesset second‐order perturbation theory (MP2) with terms linear in the interelectronic coordinates (MP2‐R12). Various atomic orbital (AO) basis sets were used to investigate the convergence of the binding energy towards the AO basis set limit. The calculations were performed at fixed geometries taken from the literature (which are geometries that were optimized at the MP2 level). Binding energies (De) of 20.9 kJ/mol (dimer), 69.2 kJ/mol (trimer), and 123.8 kJ/mol (tetramer) were obtained from MP2‐R12 calculations with a large 7s5p3d1f/5s3p1d AO basis set. These values are supposed to be very close (with errors of 2–5%) to the AO basis set limit. Binding energies obtained from CCSD(T) and MP2 calculations with the aug‐cc‐pVDZ basis set agreed within 3%. Hence, the MP2 level of calculation appeared to be appropriate to describe hydrogen‐bonding in small water clusters. All calculations were corrected for the basis set superposition error (BSSE) by the full counterpoise method.
A Pump & Dump & Probe Strategy for the Spectroscopy of the Transition State During a Laser‐Controlled Isomerization: Model Simulation for the Cope Rearrangement of 2,6‐Dicyanoethylmethylsemibullvalene
Authors: Dohle M. , Manz J. , Paramonov G. K.
Published: September 2013

Our previous strategy for laser control of isomerization by intense ultrashort (ps) infrared laser pulses is extended to the spectroscopy of the transition state during the laser‐driven chemical reaction, by means of a pump & dump & probe approach. The pump laser pulse excites a reactant state, typically the ground state, to a delocalized “transition state” with energy just above the shallow potential barrier which separates the potential wells of two near‐degenerate isomers. The dump laser pulse de‐excites the transition state to a product state, e.g. its ground state. The transient population of the transition state is monitored by another ultrashort, yet weak probe laser pulse which induces the electronic transition to the vibrational ground state of the next accessible excited electronic state. The strategy is demonstrated by a simple model simulation of the laser‐driven Cope rearrangement of 2,6‐Dicyanoethylmethylsemibullvalene (DEM‐SBV) by means of representative time‐dependent wave‐packets. This example is used for a discussion of the new pump & dumb & probe method.
Toward Laser Control of Molecular Motion
Authors: Letokhov V. S.
Published: September 2013

This paper considers the possibilities of extending to molecules the laser methods of controlling the motion of atoms. Techniques are analyzed involving the cyclic interaction between the laser field and the molecule at two energy levels by stimulated quantum transitions alone. The use of the sympathetic cooling technique is suggested for molecular ions, this potentially enabling one to obtain extremely narrow spectral lines suitable for the detection of the splitting of energy levels in molecular enantiomers due to parity violation.
The Effect of the Torsional Barrier Height on the Acceleration of Intramolecular Vibrational Relaxation (IVR) by Molecular Flexibility
Authors: Perry David S. , Bethardy G. A. , Wang Xiaoliang
Published: September 2013

Previous work by the present authors (Can. J. Chem. 72, 652 (1994)) pointed out the acceleration of IVR in flexible molecules when the prepared vibration is close to the centre of flexibility (COF). A COF was defined as a bond about which hindered internal rotation can occur thereby giving rise to molecular flexibility. Here, it is shown that the rate of IVR is inversely correlated with the height of the barrier to internal rotation for systems in which the prepared vibration is adjacent to the COF. In ethanol and hydrogen peroxide the barriers are low (≈︁ 380 cm−1) and the relaxation of the adjacent O‐H vibration is fast (4 to 26 ps). On the other hand, higher barrier torsions (1100 to 1700 cm−1) adjacent to the chromophore in 1–butyne, 2‐fluoroethanol, and 1,2‐di‐fluoroethane give rise to much longer IVR lifetimes (270 to 565 ps).

Most of the IVR lifetimes used in this paper were derived from discretely resolved spectra in which a bright state transition is fragmented into a clump of molecular eigenstates; the remainder are from rotationally selected double resonance spectra. An algorithm is described for the derivation of consistent IVR lifetimes for coupling cases ranging from intermediate down to the very sparse limit where only a few perturbing states are explicitly observed in the spectrum.
Highly Vibrationally Excited Non Rigid Molecules: Overtone Spectroscopy and Intramolecular Dynamics of Gaseous Nitromethane
Authors: Cavagnat D. , Lespade L. , Lapouge C.
Published: September 2013

The CH stretching overtone spectra of gaseous nitromethane NO2CH3 (Δv = 4 to 6) and of its monohydrogenated derivative NO2CHD2 (Δv = 2 to 6) have been recorded and analysed with a theoretical treatment which takes into account the coupling of the CH stretch with the low hindered internal rotation of the methyl group and with isoenergetic combination states by Fermi resonance. The calculated spectra reproduce well the experimental ones.
Reinvestigation of the 2v1 Band in Trifluoropropyne using a Frequency Stabilized 1.5 μm Color Center Laser in Conjunction with a Laser Field Build‐up Cavity
Authors: Gambogi Joan E. , Becucci Maurizio , O'Brien Christopher J. , Lehmann Kevin K. , Scoles Giacinto
Published: September 2013

The highly perturbed spectrum of the first overtone of the acetylenic CH stretch in trifluoropropyne has been reinvestigated with an improved multi‐laser, optothermal detection, molecular beam spectrometer. The modifications include installing a build‐up cavity to enhance the coupling between a 1.5 μm color center laser and the molecular beam, and stabilizing the laser frequency to improve the spectrometer's resolution. Upon injecting 25 mW into the cavity, a power enhancement of about 600 is measured. The laser frequency is stabilized by locking it to an external, temperature stabilized, etalon and applying the feedback to an intracavity electro‐optic crystal. The frequency stability reached is estimated to be less than 4 parts in 1010 or 75 kHz (in a 30 Hz bandwidth centered at 300 Hz).

Utilizing infrared/infrared double resonance, the K components of this highly perturbed spetrum were assigned. The results indicate that the lifetime of the acetylenic CH stretch is approximately 1.4 ns and does not change as a function of J' for 0 ≤ J' ≤4. In agreement with a previous lower resolution study [J. Chem. Phys. 95, 3891 (1991)], the P(1) clump shows an experimental density of states almost equal to the calculated one and the level spacing distribution is similar to that of a Gaussian Orthogonal Ensemble indicating chaotic classical dynamics.
The Acetylene S0 Surface: From Dispersed Fluorescence Spectra to Polyads to Dynamics
Authors: Solina Stephani Ann B. , O'Brien Jonathan P. , Field Robert W. , Polik William F.
Published: September 2013

Dispersed Fluorescence spectra of acetylene have been recorded and unzipped, through a fortuitous coincidence of FC active modes and active anharmonic resonances, there by pictorially revealing the key factors controlling the vibrational dynamics on the acetylene S0 surface. When energy is placed into very high excitation of the trans‐bend and moderate excitation of the CC stretch, three approximately conserved quantities survive, i.e., no trace of the expected total breakdown of vibrational constants of motion due to energetic access to the vinylidene isomer is observed for vibrational energies up to at least 16400 cm−1. Unzipping the DF spectrum reveals the FC intensity profiles for the acetylene Ã ↔ X̃ system with two FC active modes. Also, the unzipped DF spectrum clearly demonstrates that IVR increases within a polyad by increasing trans‐bead, v4, and by decreasing CC stretch, v2. Increasing IVR with increasing v4 or decreasing v2, are both cases where the first few resonance tiers play the dominant role in controlling IVR for the initial states prepared in these experiments, very high excitation in the trans‐bend and moderate excitation in the CC stretch.
Localization of Vibrational Excitation: A Simple Model
Authors: Schmid G. M. , Silbey R. J.
Published: September 2013

A simple model of localization of vibrational excitation in molecules is presented which is based on the idea to treat the dynamics of the molecular equilibrium configuration and the molecular oscillations around it as different degrees of freedom. From the comparison of their timescales, two limiting regimes are identified where localization occurs under formation of quasiparticles: the standard “local mode limit” and a previously undiscussed limit.
Morbidity in survivors of child and adolescent meningioma
Authors: Kotecha Rishi S. , Jacoby Peter , Cole Catherine H. , Gottardo Nicholas G.
Published: September 2013

BACKGROUND

The extent of initial surgical resection has been identified as the strongest prognostic indicator for survival in child and adolescent meningioma. Given the paucity of data concerning long‐term outcome, the authors undertook a meta‐analysis to analyze morbidity in survivors of this disease.

METHODS

Individual patient data were obtained from 19 case series published over the last 23 years through direct communication with the authors. Ordinal logistic regression models were used to assess the influence of risk factors on morbidity.

RESULTS

Of 261 patients, 48% reported a completely normal life with no morbidity, and 25% had moderate/severe meningioma‐associated morbidity at last follow‐up. Multivariate analysis identified relapse as the only independent variable associated with an increased risk of morbidity (odds ratio, 4.02; 95% confidence interval, 2.11‐7.65; P ≤ .001). Univariate analysis also revealed an increased risk for patients with neurofibromatosis (odds ratio, 1.90; 95% confidence interval, 1.04‐3.48; P = .04). Subgroup analysis identified a higher incidence of morbidity among patients who had intracranial tumors with a skull base location compared with a nonskull base location (P ≤ .001). Timing at which morbidity occurred was available for 70 patients, with persistence of preoperative tumor‐related symptoms in 67% and as a result of therapy in 20%.

CONCLUSIONS

The majority of survivors of child and adolescent meningioma had no or only mild long‐term morbidity, whereas 25% had moderate/severe morbidity, with a significantly increased risk in patients with relapsed disease. In the majority, morbidity occurred as a consequence of the tumor itself, justifying aggressive surgery to achieve gross total resection. However, for patients with neurofibromatosis and skull base meningioma, a more cautious surgical approach should be reserved. Cancer 2013;119:4350–4357. © 2013 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of the American Cancer Society.
Energy transfer induced enhancement of localized exciton emission in ZnO nanoparticle–anthracene hybrid films
Authors: Main Kyle , Shimada Ryoko , Fujita Yasuhisa , Neogi Arup
Published: September 2013

Optically transparent and high‐quality hybrid ZnO nanoparticle and anthracene embedded polyphenylsiloxane (PPS) glass films were spin‐coated on quartz substrates. A strong Förster resonant energy transfer (FRET) process was indicated by the observation of quenching of the ZnO emission and an enhancement of the anthracene emission at room temperature. The efficiency of this energy transfer between ZnO and the S1 vibronic states of the anthracene molecules can be optimized to exceed 90%.

magnified image

Visible emission from anthracene only, ZnO only, and the ZnO/anthracene hybrid. The anthracene emission is visibly more intense in the presence of ZnO.

(© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)