bluuebunny/crossref_metadata_2025 huggingface dataset:
On the choice of the driving temperature for eddy-covariance carbon dioxide flux partitioning
Authors: Lasslop G. , Migliavacca M. , Bohrer G. , Reichstein M. , Bahn M. , Ibrom A. , Jacobs C. , Kolari P. , Papale D. , Vesala T. , Wohlfahrt G. , Cescatti A.
Published: July 2012

Abstract. Networks that merge and harmonise eddy-covariance measurements from many different parts of the world have become an important observational resource for ecosystem science. Empirical algorithms have been developed which combine direct observations of the net ecosystem exchange of carbon dioxide with simple empirical models to disentangle photosynthetic (GPP) and respiratory fluxes (Reco). The increasing use of these estimates for the analysis of climate sensitivities, model evaluation, and calibration demands a thorough understanding of assumptions in the analysis process and the resulting uncertainties of the partitioned fluxes. The semi-empirical models used in flux partitioning algorithms require temperature observations as input, but as respiration takes place in many parts of an ecosystem, it is unclear which temperature input – air, surface, bole, or soil at a specific depth – should be used. This choice is a source of uncertainty and potential biases. In this study we analysed the correlation between different temperature observations and nighttime NEE (which equals nighttime respiration) across FLUXNET sites to understand the potential of the different temperature observations as input for the flux partitioning model. We found that the differences in the correlation between different temperature data streams and nighttime NEE are small and depend on the selection of sites. We investigated the effects of the choice of the temperature data by running two flux partitioning algorithms with air and soil temperature. We found the time lag (phase shift) between air and soil temperatures explains the differences in the GPP and Reco estimates when using either air or soil temperatures for flux partitioning. The impact of the source of temperature data on other derived ecosystem parameters was estimated, and the strongest impact was found for the temperature sensitivity. Overall, this study suggests that the choice between soil or air temperature must be made on site-by-site basis by analysing the correlation between temperature and nighttime NEE. We recommend using an ensemble of estimates based on different temperature observations to account for the uncertainty due to the choice of temperature and to assure the robustness of the temporal patterns of the derived variables.
The OASIS3 coupler: a European climate modelling community software
Authors: Valcke S.
Published: July 2012

Abstract. This paper presents the OASIS3 software used in five of the seven European Earth System Models (ESMs) participating to the Fifth Coupled Model Intercomparison Project (CMIP5). A short history of the coupler development and a description of its large community of users are followed by a detailed OASIS3 technical description. The performances of few relatively high resolution OASIS3 coupled models are then described and show that even if its limited field-per-field parallelism will eventually become a bottleneck in the simulation, OASIS3 can still be considered an appropriate tool for most of these relatively heavy coupled configurations. Its successful use in different CMIP5 ESMs is then detailed. A discussion of the benefits and drawbacks of the OASIS3 approach and a presentation of planned developments conclude the paper.
Imbalance of energy and momentum source terms of the sea wave transfer equation for fully developed seas
Authors: Caudal G. V.
Published: July 2012

Abstract. Using a two-dimensional empirical sea wave spectral model at full development, this paper performs an assessment of the compatibility of the energy and momentum budgets of sea waves over the whole spectral range. Among the various combinations of model functions for wave breaking and wind source terms tested, no one fulfilled simultaneously the energy and momentum balance of the transfer equation. Based on experimental and theoretical grounds, wave breaking is known to contribute to frequency downshift of a narrow-banded wave spectrum, when the modulational instability is combined with wave breaking. On those grounds, it is assumed that, in addition to dissipation, wave breaking produces a spectral energy flux directed toward low wavenumbers. I show that it is then possible to remove the energy and momentum budget inconsistency, and correlatively the required strength of this spectral flux is estimated. Assuming such a downward spectral flux permits to fulfill both energy and momentum balance conditions, while slightly reducing the consistency between source terms and empirical spectra, as estimated by a cost function K. Other tests were performed in which it was further assumed that wave breaking would also be associated with azimuthal diffusion of the spectral energy. This could allow a slight improvement of the cost function K, and might correlatively reduce the required downward spectral flux by a factor of 4, although it would not be able to remove it entirely.
Shorter peripheral blood telomeres are a potential biomarker for patients with advanced colorectal adenomas
Authors: Riegert-Johnson Douglas L. , Boardman Lisa A. , Crook Julia E. , Thomas Colleen S. , Johnson Ruth A. , Roberts Maegan E.
Published: July 2012

Background

Colorectal cancer (CRC) can be prevented by the early detection and removal of advanced adenomas (AAs) by colonoscopy. Our aim was to evaluate peripheral blood leukocyte (PBL) telomere length as a potential biomarker for the presence of AAs.

Methods

PBL telomere length was measured in patients with AAs (n=35), in a control group of similarly aged patients who had a normal colonoscopy (n=145) and in a separate population group with no history of cancer, again similarly aged (n=495). Telomere measurements were performed using a quantitative PCR assay and reported as ratios of telomere and single copy gene measurements.

Results

Telomere lengths tended to be lower in patients with AAs than in patients in the normal colonoscopy group (p<0.001) as well as those in the population group (p=0.011). A telomere/single copy gene ratio of 0.5 was found to have an estimated 94% sensitivity and a 56% specificity for AAs; a combination of sensitivity and specificity for which a value of >0.5 would reduce the odds of a patient having AAs by a factor of 0.11 (the negative likelihood ratio). Thirty three percent of individuals in the population group tested above this cutoff and could be considered at low risk for AAs.

Conclusions

PBL telomeres are shortened in patients with colorectal neoplasia, suggesting that PBL telomere length could be a promising non-invasive blood biomarker to pre-screen for risk of AAs prior to colonoscopy.
Insulin Glargine and Risk of Cancer: A Meta-Analysis
Authors: Du Xinli , Zhang Rihua , Xue Yi , Li Dong , Cai Jinmei , Zhou Suming , Huang Zhengkai , Yu Rongbin , Liu Yun
Published: July 2012

Aims

Recently, more and more attention has been drawn on the long-term effects of insulin glargine. Here we strived to estimate the association of cancer occurrence with the use of insulin glargine.

Methods

We searched all the publications regarding the association between cancer occurrence and the use of insulin glargine using the US National Library of Medicine's PubMed database. Data were independently extracted and analyzed using random or fixed effects meta-analysis depending upon the degree of heterogeneity.

Results

Seven cohort studies were included in the meta-analysis. Cancer occurrence had no significant difference in glargine-treated patients compared to patients treated with other insulins (RR=0.86, 95% CI=0.69–1.07, p=0.17, Pheterogeneity <0.00001). In our subgroup analysis, glargine, compared to other insulins, did not increase the risk of breast cancer (RR=1.14, 95% CI=0.65–2.02, p=0.65, Pheterogeneity=0.002), prostate cancer (RR=1.00, 95% CI=0.79–1.26, p=0.99, Pheterogeneity=0.78), pancreatic cancer (RR=0.57, 95% CI=0.14–2.35, p=0.44, Pheterogeneity=0.0002) and gastrointestinal cancer (RR=0.80, heterogeneity 95% CI=0.62–1.02, p=0.07, Pheterogeneity=0.86).

Conclusions

This meta-analysis of open-label studies does not support an increased cancer risk in patients treated with insulin glargine. The result provides confidence for the development of insulin glargine, but needs confirmation by further clinical studies.
Growth of ZnO Nanorod Arrays on Flexible Substrates: Effect of Precursor Solution Concentration
Authors: Tong Fei , Kim Kyusang , Wang Yaqi , Thapa Resham , Sharma Yogesh , Modic Aaron , Claude Ahyi Ayayi , Issacs-Smith Tamara , Williams John , Ahn Hosang , Park Hyejin , Kim Dong-Joo , Lee Sungkoo , Lim Eunhee , Lee Kyeong K. , Park Minseo
Published: July 2012

We report a low-temperature aqueous solution growth of uniformly aligned ZnO nanorod arrays on flexible substrates. The substrate is Indium Tin Oxide (ITO) film coated on polyethylene terephthalate (PET). Solutions with five different concentrations of the precursors with equimolar Zinc Nitrate and Hexamethylenetetramine (HMT) in distilled water were prepared to systematically study the effect of precursor solution concentration on the structural and optical properties of ZnO nanorods. It was concluded that the precursor concentration have great influence on the morphology, crystal quality, and optical property of ZnO nanorods. The diameter, density, and orientation of the nanorods are dependent on the precursor solution concentration. X-ray diffraction and micro-Raman spectroscopy showed that the ZnO nanorods with the highest concentration of 50 mM were highly aligned and have the highest level of surface coverage. It was also found that the diameter and length of the nanorods increases upon increasing precursor solution concentration. This is the first systematic investigation of studying the effect of precursor solution concentration on the quality of ZnO nanorods grown on ITO/PET substrates by low-temperature solution method. We believe that our work will contribute to the realization of flexible organic-inorganic hybrid solar cell based on ZnO nanorods and conjugated polymer.
The Effect of Three Different Feed Types on Growth Performance and Survival of African Catfish Fry (Clarias gariepinus) Reared in a Hatchery
Authors: Musa Safina M. , Aura Christopher Mulanda , Ngugi Charles Chege , Kundu Rodrick
Published: July 2012

African catfish Clarias gariepinus is cultured as food fish, used to control overpopulation in tilapia ponds, and is grown as baitfish for the Lake Victoria Nile Perch fishery. Since the demand for Clarias gariepinus fingerlings is high, many farmers wish to specialize in fingerling production. In this study, the performance of three dietary feed types: freshwater rotifers with Artemia nauplii, freshwater rotifers with fish meal, and freshwater rotifers with maize bran, on the growth performance of African catfish fry, were done in a hatchery and they were raised in 9 glass tanks for a period of 21 days. Pearson’s correlation showed no relationship (r=0.1; P>0.05) between growth and water quality parameters, but indicated a strong relationship between survival rate and total length between treatments (r=0.85; P=0.02). Mean total length (TL) after 21 days were (A=15.003), (B=12.964), and (C=11.90) in mm for Treatments A, B, and C, respectively. Treatment A had the highest specific growth rate (SGR) of 6.475% day 1 followed by B (5.5320% day−1) and C (4.960% day−1). Results from this study demonstrate that after the 7 days of feeding using rotifers, Artemia is the best feed for increasing growth of Clarias gariepinus.
Ecosystem-Wide Impacts of Deforestation in Mangroves: The Urabá Gulf (Colombian Caribbean) Case Study
Authors: Blanco J. F. , Estrada E. A. , Ortiz L. F. , Urrego L. E.
Published: July 2012

Mangroves are ecologically important and extensive in the Neotropics, but they are visibly threatened by selective logging and conversion to pastures in the Southern Caribbean. The objective of this paper was to summarize the impacts of both threats on forest structure, species composition, aboveground biomass and carbon reservoir, species introgressions, and benthic fauna populations by collating past and current data and by using an interdisciplinary approach in the Urabá Gulf (Colombia) as a case study. Mangroves in the Eastern Coast have been decimated and have produced unskewed tree-diameter (DBH) distributions due to the overexploitation of Rhizophora mangle for poles (DBH range: 7–17 cm) and of Avicennia germinans for planks and pilings (DBH >40 cm). Selective logging increased the importance value of the light-tolerant white mangrove Laguncularia racemosa, also increasing biomass and carbon storage in this species, thus offsetting reductions in other species. Introgressions (cryptic ecological degradation) by L. racemosa and Acrostichum aureum (mangrove fern) and low densities of otherwise dominant detritivore snails (Neritina virginea) were observed in periurban basin mangroves. Finally, basin mangroves were more threatened than fringing mangroves due to their proximity to expanding pastures, villages, and a coastal city.
Intracellular Human Papillomavirus E6, E7 mRNA Quantification Predicts CIN 2+ in Cervical Biopsies Better Than Papanicolaou Screening for Women Regardless of Age
Authors: Pierry Deirdre , Weiss Gerald , Lack Benjamin , Chen Victor , Fusco Judy
Published: July 2012

Context.—Cervical cancer screening in women younger than 30 years relies on cervical cytology because of the poor performance of human papillomavirus (HPV) DNA testing in this age group.

Objectives.—To determine the performance of in-cell HPV E6, E7 mRNA quantification (HPV OncoTect) for the detection of high-grade cervical intraepithelial neoplasia in women younger than 30 years.

Design.—We analyzed 3133 cytology specimens from a screening population of women aged 19–75 years investigate HPV OncoTect as a triage/secondary screening test for atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesion (LSIL) cytology in women younger than 30 years. Test results were compared to histology in 246 cases.

Results.—The sensitivity of E6, E7 mRNA was 89% for CIN 2+ and 100% for CIN 3+ lesions in women 30 years and older. In women younger than 30 years, the sensitivity of E6, E7 mRNA for CIN 2+ lesions was 88% for CIN 2+ and 92% for CIN 3+ lesions. Abnormal cytology (≥ASCUS) exhibited a sensitivity of 89% for CIN 2+ and 100% for CIN 3+ in women 30 years and older and 96% sensitivity for CIN 2+ and 93% sensitivity for CIN 3+ in women younger than 30. The specificity of E6, E7 mRNA was >80% for CIN 2+ and CIN 3+ in both groups of women compared to a specificity of abnormal cytology of <10% for CIN 2+ and CIN 3+ in both groups.

Conclusions.—HPV OncoTect demonstrates a performance that would be effective for ASCUS/LSIL triage in women including those younger than 30 years.
Gastroblastoma in a 28-Year-Old Man With Nodal Metastasis: Proof of the Malignant Potential
Authors: Wey Elizabeth A. , Britton Andrew J. , Sferra Joseph J. , Kasunic Tim , Pepe Linda R. , Appelman Henry D.
Published: July 2012

Gastroblastoma is a newly defined neoplasm of children and young adults with only 4 reported cases to date. Morphologically, the tumor is a mixture of epithelial structures and stromal elements with minimal cytologic atypia. In these 4 reported cases, there were no metastases or postresection recurrences. We report a case of gastroblastoma in a 28-year-old man with a histologic nodal metastasis and clinical distant metastases.
Transformation of Indolent Mantle Cell Lymphoma to Pleomorphic Mantle Cell Lymphoma: Case Report and Review of Clinical and Morphologic Variants
Authors: Kiel Mark J. , Smith Lauren B.
Published: July 2012

We report a case of indolent mantle cell lymphoma with progression to pleomorphic mantle cell lymphoma 8 years after initial presentation. The first lymph node biopsy showed expanded mantle zones composed of uniformly small B lymphocytes. A cyclin D1 immunohistochemical stain was negative and the patient was observed. Eight years later, the patient developed symptomatic splenomegaly. Microscopic examination of the spleen revealed expanded mantle zones with an increased number of large cells with irregular nuclear contours. Immunohistochemistry for cyclin D1 was positive. A repeat cyclin D1 immunohistochemical staining performed on the initial lymph node biopsy was positive, indicating an inadequate initial study. Immunoglobulin heavy-chain gene rearrangement studies confirmed clonal identity. A revised diagnosis of indolent mantle cell lymphoma with progression to pleomorphic mantle cell lymphoma was rendered. The differential diagnosis of mantle cell lymphoma, including clinical and morphologic variants, is discussed.
Clear Cell Tumors of the Central Nervous System: A Case-Based Review
Authors: Camelo-Piragua Sandra
Published: July 2012

Clear cell tumors of the central nervous system (CNS) encompass a variety of tumor subtypes that are challenging to diagnose given their similar morphologic features. Here, I use a case-based approach to review the clinicopathologic and radiologic features to help guide the general pathologist in the diagnosis of clear cell tumors of the CNS. First, the reader is invited to study 6 images of different CNS tumors with clear cell morphology. Then, each case is expanded in light of clinical and radiologic data and includes a histopathologic description of the tumor. A brief discussion follows with up-to-date diagnostic tools. Finally, I propose an immunohistochemical algorithm to navigate through the complex features that characterize clear cell tumors of the CNS. This review aims to provide a comprehensive approach to diagnosing clear cell neoplasms of the CNS based on improved assessment of the clinicopathologic and radiologic features of each entity.
CyberKnife Radiosurgery for the Treatment of Orbital Metastases
Authors: Klingenstein A. , Kufeld M. , Wowra B. , Muacevic A. , Fürweger C. , Schaller U. C.
Published: July 2012

Purpose of this study is to evaluate radiographic therapy response, clinical outcome and adverse effects of CyberKnife radiosurgery in patients suffering from orbital metastases. Sixteen orbital metastases originating from different solid cancers in fourteen patients were treated by single fraction CyberKnife radiosurgery. Radiographic response and clinical outcome were evaluated. The treated tumor volume ranged from 0.2 to 35 cm3 (median 2.3 cm3, mean 7.0 cm3, SD ± 10.4 cm3, CI 0.9–9.4 cm3). The prescription dose ranged from 16.5–21 Gy (median 18 Gy, mean 18.2 Gy, SD ± 1.2 Gy, CI 17.0–18.4 Gy). A no change situation was observed in nine lesions, partial remission in four as well as complete remission in one metastasis. Tumor growth was stabilized or regressive following CyberKnife therapy in 87% of the cases. Recurrence was observed in two cases (13%). Before therapy, three patients suffered from visual disturbance and five patients reported diplopia. Six patients had no initial symptoms. After therapy, one patient indicated improvement of the present visual deficit and two patients no change. Out of the two patients with persistent diplopia, two reported improvement after therapy and three no change. No progression of symptoms was noted in any of the cases. Fourteen out of sixteen treated lesions were stable or regressive following CyberKnife radiosurgery (87%). As no serious adverse effects were reported in this series, CyberKnife therapy was shown to be of great value for local management of orbital metastases.
Analysis of a Metalloporphyrin Antioxidant Mimetic (MnTE-2-PyP) as a Radiomitigator: Prostate Tumor and Immune Status
Authors: Mehrotra S. , Pecaut M. J. , Freeman T. L. , Crapo J. D. , Rizvi A. , Luo-Owen X. , Slater J. M. , Gridley D. S.
Published: July 2012

Due to radiation-induced immune depression and development of pathologies such as cancer, there is increasing urgency to identify radiomitigators that are effective when administered after radiation exposure. The main goal of this study was to determine the radiomitigation capacity of MnTE-2-PyP[Mn(III) tetrakis (N-ethylpyridinium-2-yl) porphyrin], a superoxide dismutase (SOD) mimetic, and evaluate leukocyte parameters in spleen and blood. C57BL/6 mice were total-body exposed to 2 Gy γ-rays (Co-60), i.e., well below a lethal dose, followed by subcutaneous implantation of 5 × 105 RM-9 prostate tumor cells and initiation of MnTE-2-PyP treatment (day 0); interval between each procedure was 1–2 h. The drug was administered daily (12 times). Tumor progression was monitored and immunological analyses were performed on a subset per group on day 12. Animals treated with MnTE-2-PyP alone had significantly slower tumor growth compared to mice that did not receive the drug (P < 0.05), while radiation alone had no effect. Treatment of tumor-bearing mice with MnTE-2-PyP alone significantly increased spleen mass relative to body mass; the numbers of splenic white blood cells (WBC) and lymphocytes (B and T), as well as circulating WBC, granulocytes, and platelets, were high compared to one of more of the other groups (P < 0.05). The results show that MnTE-2-PyP slowed RM-9 tumor progression and up-regulated immune parameters, but mitigation of the effects of 2 Gy total-body irradiation were minimal.
Direct Response to Proton Beam Linear Energy Transfer (LET) in a Novel Polymer Gel Dosimeter Formulation
Authors: Lopatiuk-Tirpak O. , Su Z. , Li Z. , Zeidan O. A. , Meeks S. L. , Maryanski M. J.
Published: July 2012

Linear energy transfer (LET) of clinical proton beams is an important parameter influencing the biological effects of radiation. This work demonstrates LET-induced response enhancement in novel formulations of polymer gel dosimeters, potentially useful for LET mapping of clinical proton beams. A series of four polymer gel dosimeters (labeled A through D), prepared based on the BANG3-Pro2 formulation, but with varying concentrations of polymerization modifiers, were irradiated by a clinical proton beam with a spread out Bragg peak modulation (SOBP) and read out using the OCTOPUS-IQ optical CT scanner. The evaluation of optical density profiles in the SOBP (constant physical dose) revealed response deviations at the distal end consistent with variations in gel composition. Maximum response deviations were as follows: −3% (under-response) for gel A, and over-response of 2%, 12%, and 17% for gels B, C, and D, respectively, relative to the mean dose in the center of the SOBP. This enhancement in optical response was correlated to LET by analytical calculations. Gels A and B showed no measurable dependence on LET. Gel C responded linearly in the limited range from 1.5 to 3.5 keV/μm. LET response of gel D was linear up to at least 5.5 keV/μm, with the threshold at about 1.3 keV/μm. These results suggest that it may be possible to develop a polymer gel system with direct optical response to LET for mapping of LET distributions for particle therapy beams.
Adaptive fuzzy output feedback backstepping control of pure‐feedback nonlinear systems via dynamic surface control technique
Authors: Tong Shaocheng , Li Yongming
Published: July 2012

In this paper, an adaptive fuzzy backstepping dynamic surface control approach is considered for a class of uncertain pure‐feedback nonlinear systems with immeasurable states. Fuzzy logic systems are first employed to approximate the unknown nonlinear functions, and then an adaptive fuzzy state observer is designed to estimate the immeasurable states. By the combination of the adaptive backstepping design with a dynamic surface control technique, an adaptive fuzzy output feedback backstepping control approach is developed. It is proven that all the signals of the resulting closed‐loop system are semi‐globally uniformly ultimately bounded, and the observer and tracking errors converge to a small neighborhood of the origin by choosing the design parameters appropriately. Simulation examples are provided to show the effectiveness of the proposed approach. Copyright © 2012 John Wiley & Sons, Ltd.
Real time indicators of material refinement in an attritor mill
Authors: Santhanam Priya R. , Dreizin Edward L.
Published: July 2012

Power, torque, and rotation speed of the impeller of an attritor mill were measured during preparation of metal matrix composite powders. Compositions of Al·MgO and Al·B4C were selected to include ductile (Al) and brittle components. Brittle components, MgO, and B4C, were respectively softer and harder than the milling media (hardened steel). Yield strength of pressed powder compacts and x‐ray diffraction peak width were treated as indicators of the achieved structural refinement. Both peak width and yield strength increased for both materials at longer milling times. Torque and power increased for Al·MgO but decreased for Al·B4C at longer milling times. The results were interpreted considering differences in hardness of MgO and B4C. Amplitudes of rapid oscillations of the milling process parameters were also monitored and were observed to correlate with the material refinement. Utility of real‐time milling progress indicators for different types of materials is demonstrated. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1088–1095, 2013
Advanced FO membranes from newly synthesized CAP polymer for wastewater reclamation through an integrated FO‐MD hybrid system
Authors: Su Jincai , Ong Rui Chin , Wang Peng , Chung Tai‐Shung , Helmer Bradley J. , de Wit Jos S.
Published: July 2012

A new cellulose acetate propionate (CAP) polymer has been synthesized and used to prepare high‐performance forward osmosis (FO) membranes. With an almost equal degree of substitution of acetyl and propionyl groups, the CAP‐based dense membranes show more balanced physicochemical properties than conventional cellulose acetate (CA)‐based membranes for FO applications. The former have a lower equilibrium water content (6.6 wt. %), a lower salt diffusivity (1.6×1014 m2 s−1) and a much lower salt partition coefficient (0.013) compared with the latter. The as‐prepared and annealed CAP‐based hollow fibers have a rough surface with an average pore radius of 0.31 nm and a molecular weight cut off of 226 Da. At a transmembrane pressure of 1 bar, the dual‐layer CAP‐CA hollow fibers show a pure water permeability of 0.80 L m−2 h−1 bar−1 (LMH/bar) and a rejection of 75.5% to NaCl. The CAP‐CA hollow fibers were first tested for their FO performance using 2.0 M NaCl draw solution and deionized water feed. An impressive water flux of 17.5 L m−2 h−1 (LMH) and a reverse salt flux of 2.5 g m−2 h−1 (gMH) were achieved with the draw solution running against the active CAP layer in the FO tests. The very low reverse salt flux is mainly resulting from the low salt diffusivity and salt partition coefficient of the CAP material. In a hybrid system combining FO and membrane distillation for wastewater reclamation, the newly developed hollow fibers show very encouraging results, that is, water production rate being 13–13.7 LMH, with a MgCl2 draw solution of only 0.5 M and an operating temperature of 343 K due to the incorporation of bulky propionyl groups with balanced physiochemical properties. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1245–1254, 2013
Refining psychiatric phenotypes for response to treatment: Contribution of LPHN3 in ADHD
Authors: Labbe Aurelie , Liu Andy , Atherton Juli , Gizenko Natalie , Fortier Marie‐Ève , Sengupta Sarojini M. , Ridha Joober
Published: July 2012

Attention deficit/hyperactivity disorder (ADHD) is a heterogeneous disorder characterized by inappropriate levels of attention, hyperactivity, and impulsivity. Although a strong genetic component to the disorder has been established, the molecular genetic underpinnings of this disorder remain elusive. Recently, several studies have reported an association between polymorphisms within the latrophilin 3 gene (LPHN3) and ADHD. Interestingly, the same single‐nucleotide polymorphism conferring susceptibility to ADHD has also been found to predict efficacy of stimulant medication in children. The main objectives of the current article are: (i) To tackle the phenotype heterogeneity issue in ADHD by defining an objective and quantitative measure of response to treatment in a sample of ADHD children based on a hand held automatic device (Actiwatch) and (ii) to use this measure to reproduce for the first time the association between LPHN3 variants and response to methylphenidate (MPH) using a double‐blind, placebo‐controlled crossover experimental design. The results of our study confirm the hypothesis that LPHN3 is associated with response to MPH in ADHD children. Although this will require further validation, our work suggests that the use of an objective measure of response to treatment, such as the change in the child's motor activity measured by Actiwatch, has the potential to uncover genetic association signals that in some conditions might not be obtained using more subjective measures, such as the clinical consensus rating, for example. © 2012 Wiley Periodicals, Inc.
Cortical Circuitry Associated With Reflex Cardiovascular Control in Humans: Does the Cortical Autonomic Network “Speak” or “Listen” During Cardiovascular Arousal
Authors: Shoemaker J. Kevin , Wong Savio W. , Cechetto David F.
Published: July 2012

Beginning with clinical evidence of fatal cardiac arrhythmias in response to severe stress, in epileptic patients, and following stroke, the role of the cerebral cortex in autonomic control of the cardiovascular system has gained both academic and clinical interest. Studies in anesthetized rodents have exposed the role of several forebrain regions involved in cardiovascular control. The introduction of functional neuroimaging techniques has enabled investigations into the conscious human brain to illuminate the temporal and spatial activation patterns of cortical regions that are involved with cardiovascular control through the autonomic nervous system. This symposia report emphasizes the research performed by the authors to understand the functional organization of the human forebrain in cardiovascular control during physical stressors of baroreceptor unloading and handgrip exercise. The studies have exposed important associations between activation patterns of the insula cortex, dorsal anterior cingulate, and the medial prefrontal cortex and cardiovascular adjustments to physical stressors. Furthermore, these studies provide functional anatomic evidence that sensory signals arising from baroreceptors and skeletal muscle are represented within the insula cortex and the medial prefrontal cortex, in addition to the sensory cortex. Thus, the cortical pathways subserving reflex cardiovascular control integrate viscerosensory inputs with outgoing traffic that modulates the autonomic nervous system. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Charge Transfer across Organic Photoconductor/Insulating Liquid Interface. Part I: Metal Free Phthalocyanine/Alkanes
Authors: Ahuja R. C. , Hauffe K.
Published: July 2012

In order to understand the decisive step in the photoelectrophoretic image formation i. e. the charge exchange between inert and photosensitive particles, we report in part I of a series of papers the charge transfer across metal free x‐Phthalocyanine/Octane and Dodecane interfaces. The electron injection from the photoconductor into the organic liquid as a function of intensity and wavelength of light, and electric field has been studied using a transient measurement technique. It was found that oxygen is the most dominant species in alkanes which is responsible for the negative charge transfer from the photoconductor into the alkanes. The values of the interfacial charge transfer efficiency and quantum yield have been calculated from experimental data and were found to be in agreement with the previous results. The photoinjected charge follows the absorption spectrum of x‐Phthalocyanine qualitatively and was found to be dependent on the electric field and the intensity of light.
A High Pressure Study of the Phase Diagram and the Critical Exponent β of Binary Liquid Systems
Authors: Sivaraman A. , Tiwari M. K. , Jyothi S. , Gopal E. S. R.
Published: July 2012

The pressure dependence of critical parameters xc, Tc, and β have been analysed in four systems namely cyclohexane + acetic anhydride, n‐heptane + acetic anhydride, methanol + n‐heptane, and carbon disulphide + acetonitrile. The separation temperature was found to increase linearly with pressure the value of dTc/dP being 28 mK, 11 mK, 22 mK, and 25 mK respectively. These are in fair agreement with earlier measurements available for two systems. For the methanol + n‐heptane system dTc/dP is apparently not consistent with the value predicted from the specific heat and thermal expansion data.
Anreicherung von Indium an Pseudophasengrenzen zwischen In‐dotierten Halbleitern
Authors: Leute Volkmar , Flötotto Burkhard , Schmidtke Heinrich M.
Published: July 2012

Durch die Grenzfläche zwischen In‐dotierten HgSe‐ und HgTe‐Kristallen sowie zwischen In‐dotierten PbSe‐ und PbTe‐Kristallen erfolgt beim Tempern ein In‐Transport, obwohl anfangs die In‐Konzentration beiderseits der Grenzfläche gleich groß war. Die In‐Anreicherung in den Selenidphasen läßt sich durch eine vom Selenidgehalt abhängige Leerstellendichte erklären. Mit einsetzender Chalkogeninterdiffusion zwischen Selenid‐ und Telluridbereich geht die In‐Anreicherung wieder zurück. Im Pb‐Chalkogenidsystem kommt es im unteren Temperaturbereich zur Ausscheidung von Indiumselenid im PbSe.
Zur thermodynamischen Interpretation von1H‐NMR‐Verschiebungsdaten mit Gittermodellen
Authors: Kietz E. , Bittrich H.‐ J.
Published: July 2012

Für ausgewählte binäre Systeme von Nichtelektrolyten wurde versucht, die Molenbruchabhängigkeit der protonenchemischen Verschiebung mit den Ansätzen des Guggenheim‐ bzw. des Uniquac‐Modells zu interpretieren. Im Rahmen der vorgenommenen Untersuchungen erweist sich das Uniquac‐Modell der quasichemischen Näherung von Guggenheim überlegen. Diese Überlegenheit äußert sich sowohl bei der Wiedergabe der Molenbruchfunktion der chemischen Verschiebung als auch bei der thermodynamischen Interpretation der erhaltenen Wechselwirkungsparameter.
Pulse Radiolysis of Arenediazonium Salts in Water/tert.‐Butanol
Authors: Brede O. , Mehnert R. , Naumann W. , Becker H. G. O.
Published: July 2012

The pulse radiolysis of benzenediazonium tetrafluoroborate and its p‐NMe2, p‐MeO, p‐Me, p‐Cl, p‐COOEt, and p‐CN derivatives was studied in water/tert.‐butanol mixtures. Absorption spectra observed at wavelengths between 400 and 700 nm were attributed to the recombination products (tetrazadienes) Ar  N = N  N = N  Ar of arenediazo radicals Ar  N = N* which are generated by a diffusion‐controlled reaction of the solvated electrons with the solute. The recombination of Ar  N = N* competes with an unimolecular decay of these radicals. According to an inhomogeneous initial distribution of Ar  N = N* the apparent rate of the recombination reaction is higher than the diffusion‐controlled limit. For the unimolecular decay of Ar  N = N* rate constants between (1.8 and 330) · 105s−1 were calculated. The tetrazadienes decompose unimolecularly with rate constants from (0.3 to 17) · 105s−1. — The rate constants of the decay of the arenediazo radicals as well as of the decomposition of tetrazadienes exhibit good Hammet plots with almost identical reaction constants indicating similar paths of nitrogen elimination.
The Role of Relaxational Processes in Resonant Optoacoustic Spectroscopy
Authors: Frank Klaus , Hess Peter
Published: July 2012

An apparatus for resonant optoacoustic spectroscopy is described. The dispersion of the acoustic resonance frequency and the variation of the frequency bandwidth was studied as a function of pressure in the vibrational relaxation region for pure CH4 and mixtures with Xe and H2. These measurements yield the corresponding relaxation times and a better understanding of the dissipation effects caused by energy transfer processes. The role played by other loss mechanisms is also discussed.
Calculation of the Influence of Density on the Thermal Conductivity of Gaseous Mixtures
Authors: Kestin J. , Wakeham W. A.
Published: July 2012

The scheme for the prediction of the thermal conductivity of dense gas mixtures, proposed by Mason and his collaborators, is critically examined, for the first time, with respect to accurate experimental data for eight systems. The systems studied are binary monatomic mixtures of He  Ar and Ne  Ar; a ternary mixture, Ne  Ar  Kr; the mixtures He  H2, He  N2, Ne  N2, and Ar  N2, which involve one polyatomic component; and the mixture H2  D2 which has two polyatomic components. The experimental results used for the comparison refer to a temperature of 27.5°C and extend over the pressure range 0.6–12 MPa. — For binary and ternary systems whose components have molecular mass ratios in the range 1 – 2, the calculation scheme is found to predict the thermal conductivity with a deviation from the experimental data which does not exceed ± 0.8% even when the mixtures contain polyatomic components. However, for mixtures where the molecular mass ratio is larger, the agreement is significantly poorer and deviations amounting to as much as 2.5% are observed. These larger deviations are attributed to the inadequacy of the first‐order kinetic theory formulae upon which the prediction scheme is based.
The system hydrogen ‐ water up to 440°C and 2500 bar pressure
Authors: Seward T. M. , Franck E. U.
Published: July 2012

The system H2— H2O has been studied isochorically from 0.5 to 90 mol‐% H2and up to 440°C and 2500 bar pressure using an autoclave containing two sapphire windows through which phase transitions could be observed at elevated temperatures and pressures. — The system was found to exhibit so‐called “gas‐gas” immiscibility with a critical curve proceeding to higher temperatures and pressures from the critical point of pure water. Within the range of these experiments, the critical temperature of H2—H2O mixtures does not change greatly from that of pure water (e.g.Tc= 381.3°C atpc= 2520 bar for 38 mol‐% H2).pVTmeasurements have been made in the homogeneous region and excess volumes have been calculated at 400°C and at different pressures. At 300 bar, the excess volumes are relatively large and positive (e.g.VE= 58.0 cm3mol−1at 40 mol‐% H2) whereas at 2500 bar, excess volumes of H2—H2O mixtures indicate only small positive or negative departures from ideality.
Molecular dynamics simulation study of the negative hydration effect in aqueous electrolyte solutions
Authors: Geiger A.
Published: July 2012

To study the structure breaking effect in aqueous electrolyte solutions (also termed negative hydration), a series of molecular dynamics simulation runs has been carried out. An originally uncharged, nonpolar spherical solute particle (“Xenon”) is charged step by step fromg1= 0.0etoq1= +0.67e, + 1.0eandq1= +2.0e(eis the positive elementary charge). At zero charge the occurrence of hydrophobic hydration is observed. The surroundings of the divalent cation also shows marked structuring: the normal “positive” ionic hydration. In an intermediate region of charge (atq1= 1.0e) negative hydration is detected, which proves to be a state of minimum order. Structural changes are discussed by using pair and three particle correlation functions. Hydration energies, binding energies and pair interaction energy distributions are determined. The microdynamics is studied by observing the reorientational motion and the self diffusion behaviour of the water molecules in different regions. A zone of increased mobility is located in the vicinity of the ion, which may include the innermost hydration shell. Additionally a system comprising a negatively hydrated anion has also been studied.
Heterogeneous catalytic degradation of chlorofluoromethanes on zinc oxide surfaces
Authors: Filby W. G. , Mintas M. , Güsten H.
Published: July 2012

The decomposition of the spray propellants CFCl3 and CF2Cl2 on the surface of variously treated zinc oxides has been studied by X‐ray photoelectron spectroscopy. Whereas decomposition on “untreated” surfaces could only be induced photolytically ( λ < 400 nm) “activated” surfaces caused both spontaneous dark and additionally, photocatalytic decomposition. Indications are that the mechanism involves interaction between physisorbed substrate molecules and surface electrons of the catalyst. Decomposition causes chlorination of the zinc oxide resulting in a surface approaching hypochlorite‐perchlorate stochiometry.
Master equations for photochemistry with intense infrared light (IV). A unified treatment of case B and case C including nonlinear effects
Authors: Quack Martin
Published: July 2012

A unified master equation for unimolecular reactions induced by monochromatic infrared radiation (URIMIR) is presented. Its effective rate coefficient matrix covers both case B (Pauli equation) and case C, properly including the nonlinearity of the latter. Exact quantum mechanical model solutions are compared with results from the approximate unified master equation. The exact analytical solutions of the master equation are presented for the URIMIR of some realistic molecular models. The important new properties of the transition range between case B and case C are quantitatively discussed with respect to time dependent and steady state level populations, time dependent and steady state rate coefficients and their nonlinear intensity dependence, and with respect to the influence of molecular properties. The role of case C for the interpretation of static field effects and its importance for efficient isotope separation are pointed out.
A Molecular Beam Apparatus for the Investigation of Radical Reactions: The Reaction CH3 + Br2 → CH3Br + Br at a Collision Energy of 36 kJ/mol
Authors: Somssich P. , Strein K. , Schmiedel H.
Published: July 2012

The reaction of CH3 + Br2 → CH3Br + Br was studied in a crossed molecular beam apparatus at a collision energy of 36.3 kJ/mol. Two heatable nozzles provide intensive and fast beams of Br2 (950 m/sec) and CH3 radicals (2096 m/sec), the latter of which are formed by pyrolysis of (CH3)2Hg. By using a pseudorandom TOF chopper, velocity analysis of the product CH3Br was made possible despite the very low flux involved. The CH3Br product angular distribution peaks at a center of mass angle of θ ∼ 100°. The reactive scattering of CH3Br can still be characterized as backward scattering with respect to the CH3 beam although an unmistakable tendency towards sideward scattering with increasing collision energy is observed, when compared to measurements at an energy of only 18 kJ/mol. The proportion of the average translational energy after the collision was found to be approximately 0.5 of Etot. The observed distribution leads to the conclusion that the dominant potential surface of the reaction is of the repulsive type (late downhill).
The Temperature Dependence of the Binary Diffusion Coefficients of the Systems Ne‐CO2, Kr‐CO2 and Xe‐CO2
Authors: Robjohns H. L. , Dunlop Peter J.
Published: July 2012

Binary diffusion coefficients are reported for the systems Ne‐CO2, Kr‐CO2 and Xe‐CO2 over the temperature range 277 – 323 K, and combined with accurate second virial coefficients to obtain (m, 6, 8) potentials for the unlike‐interactions. These potentials, together with others for the like‐interactions, have been used to calculate binary viscosities for comparison with existing data.
Neutron Scattering from Concentrated Micellar Solutions
Authors: Hayter John B.
Published: July 2012

Aqueous solutions of sodium dodecyl sulphate have been studied by neutron small‐angle scattering at concentrations up to 0.8 mol dm−3, with up to 0.2 mol dm−3 of added NaCl. The data were analysed taking specific account of intermicellar correlations, to obtain a single micelle form‐factor which is consistent with a Hartley‐like model with a rough outer surface. The measured structural parameters were used to predict the solution dynamics, and the results were confirmed using dynamic neutron spin‐echo spectroscopy.
Melting Curves, Densities, Viscosities and Thermodynamic Excess Properties of 1,2,4‐Trichlorobenzene + n‐Decane and + n‐Tetradecane
Authors: Atrops H. , Kalali H. E. , Kohler F.
Published: July 2012

Melting curves, viscosities and densities have been determined for the mixtures of 1,2,4‐trichlorobenzene + n‐decane and + n‐tetradecane. Derived thermodynamic excess properties (excess Gibbs energy gE and excess volume vE) can be combined with literature data on trichlorobenzene + n‐alkane systems to establish an unusual trend of mixing properties with chain length of n‐alkane. Also viscosities of equimolar mixtures of trichlorobenzene with various n‐alkanes and of benzene with various n‐alkanes have been measured, in order to collect more material on the behaviour of n‐alkane mixtures.
The Reversible Hydration of Carbonyl Compounds in Aqueous Solution Part II: The Kinetics of the Keto/Gem‐diol Transition
Authors: Buschmann Hans‐JüRgen , Dutkiewicz Edward , Knoche Wilhelm
Published: July 2012

The kinetics of hydration of 17 different carbonyl compounds have been studied in acidic solution. The reactions have been found to be acid‐catalysed. For the aliphatic aldehydes propanal to hexanal the rate constants are k0 = (3.5 ± 1) · 10−3 s−1 and kH = (450 ± 30) dm3 mol−1 s−1 and for α‐keto acids they are in the ranges k0 = (0.13 to 0.40) s−1 and kH = (1 to 6) dm3 mol−1 s−1. For halogenated acetones the rate constants depend strongly on the substituents. The large negative value for the reaction entropy ΔS0 = −70 J mol−1 K−1 indicates that three water molecules are involved in the hydration process.
Selfsensitization of the Photopolymerization of Diacetylenes Studied in Multilayers
Authors: Bubeck C. , Tieke B. , Wegner G.
Published: July 2012

The photoreactivity of multimolecular Langmuir‐Blodgett layers is studied with optical absorption spectroscopy. Whereas the polymerization of monomeric layers can be initiated by UV‐irradiation only, irradiation of partially polymerized layers with visible light up to λ ≤ 500 nm leads to a continuation of the reaction. The maximal polymer yield obtained with UV‐ and visible light irradiation is the same. The action spectra of the chain growth of partially polymerized layers and of the photoconductivity correspond to each other. A new mechanism of the chain growth is proposed.
Fast Reaction Rates in IR‐Photochemistry: c‐C4F8 → 2 C2F4
Authors: Quack M. , Seyfang G.
Published: July 2012

Quantitative experimental results are reported for the photo‐decomposition of octafluorocyclobutane under irradiation with intense, mono‐chromatic light from a pulsed TEA‐CO2‐laser in the range of the v21 fundamental near 963 cm−1. The IR‐photochemical rate coefficient is found to be

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for irradiation with P 8 at 954.6 cm−1, close to the optimum frequency. It is shown that the intensity dependence is linear to a good approximation by comparing irradiation with intense self‐mode‐locked pulse trains and smooth single mode pulses of low peak intensity, generated by means of an intracavity absorber. Results on the frequency dependence and upon the influence of inert gas pressure in the IR‐photochemistry of C4F8 are reported. The experimental results are found to compare well with theoretical predictions based on a Pauli equation treatment and simple models for the rate coefficient matrix.