bluuebunny/crossref_metadata_2025 huggingface dataset:
Tonsil size as a predictor of cardiac complications in children with sleep‐disordered breathing
Authors: Granzotto Eduardo Homrich , Aquino Flavio Veras , Flores José Antônio , Neto José Faibes Lubianca
Published: May 2010

Objectives/Hypothesis:

The primary objective was to evaluate the association of palatine (T/P) tonsil size determined by radiography with pulmonary artery pressure (PAP) measured by Doppler echocardiography in children with surgical indication for adenotonsillar hypertrophy. The secondary objective was to evaluate if tonsil size could help to identify children at higher risk of pulmonary artery hypertension (PAH).

Study Design:

Cross‐sectional study.

Methods:

The study was conducted with a consecutive sample of children with indication of adenotonsillectomy for sleep‐disordered breathing. T/P was measured by lateral neck radiography, PAP by echodopplercardiography, and symptoms and quality of life by the Obstructive Sleep Apnea (OSA)‐18 questionnaire. T/P was plotted in a receiver operating characteristic (ROC) curve to determine the best cut‐off point to identify children with PAH.

Results:

A total of 45 children participated in the study. The mean age was 72.0 ± 32.3 months, and six (13%) patients had PAH. Correlation between systolic PAP and T/P was strong (r = 0.624; P < .0001). T/P was significantly higher in patients with PAH (P < .001). OSA‐18 score did not significantly correlate with the variables. The cut‐off point identified in the ROC was 0.66, which was the minimum T/P where sensitivity was still 100%. Mean systolic pulmonary artery pressure in children with T/P >0.66 was significantly higher than in those with T/P <0.66 (P < .001).

Conclusions:

T/P showed a good correlation with PAP in children with adenotonsillar hypertrophy and surgical indication for sleep‐disordered breathing. Children with T/P >0.66 can be at greater risk for cardiac complications and should be submitted to complementary studies with echodopplercardiography or given preference for surgery.
The role of intratympanic lactate injection in the prevention of cisplatin‐induced ototoxicity
Authors: Nader Marc‐Elie , Théorêt Yves , Saliba Issam
Published: May 2010

Objectives/Hypothesis:

There is no approved agent to prevent cisplatin‐induced ototoxicity. Our objectives were to: 1) identify and compare the effect of intratympanic injections of lactate or N‐acetylcysteine (NAC) in the prevention of cisplatin‐induced ototoxicity, 2) investigate inner ear protection using a scanning electron microscope, and 3) study systemic diffusion of intratympanic NAC.

Study Design:

Prospective animal study.

Methods:

Sixteen guinea pigs formed two groups, and respectively received intratympanic lactate and 20% NAC in one ear. The contralateral ears received a control saline solution. After 30 minutes, an intraperitoneal cisplatin injection of 3 mg/kg was performed and repeated eight times, once a week, to achieve 24 mg/kg. Auditory brainstem responses (ABRs) were recorded before any injection, after 9 mg/kg and after 24 mg/kg of cisplatin for the frequencies 2, 4, 6 and 8 kHz. Cochleas were analyzed under scanning electron microscope. Systemic diffusion of NAC was studied using high‐performance liquid chromatography.

Results:

For the control ears, ABR thresholds increased uniformly and averaged 28.4 dB. The lactate group showed a lower threshold increase and averaged 17.0 dB. The NAC showed an important threshold increase of 89.0 dB. Lactate showed a significant hearing protection at 2000 Hz (P < .01). Electron microscopy revealed partial preservation of outer hair cell stereocilia for the ears treated with lactate and severe disruption for NAC group. No systemic diffusion of NAC was observed with chromatography.

Conclusions:

Intratympanic lactate offers significant partial protection against cisplatin‐induced ototoxicity at midfrequencies. High‐concentration NAC does not seem a viable solution as it causes a considerable inflammatory reaction. NAC does not diffuse systemically.
Barriers to the implementation of competency‐based education and assessment: A survey of otolaryngology program directors
Authors: Laeeq Kulsoom , Weatherly Robert A. , Masood Hamid , Thompson Richard E. , Brown David J. , Cummings Charles W. , Bhatti Nasir I.
Published: May 2010

Objectives/Hypothesis:

To identify the barriers faced by otolaryngology program directors as they implement competency‐based education and assessment and to identify preferred approaches to meet these challenges as suggested by program directors.

Study Design:

A national survey of otolaryngology–head and neck surgery program directors.

Methods:

We developed a 20‐item questionnaire that was distributed to 102 otolaryngology program directors through SurveyMonkey. Nonrespondents were reminded by follow‐up email and phone calls. Results were analyzed by descriptive statistical analysis.

Results:

A total of 88 (86%) program directors responded to the survey. There was a marked discrepancy between the income received and time spent performing the duties of the program director. Program director workload was recognized as the most important barrier to the implementation of competency‐based education. Creating a practical clearinghouse of existing and emerging assessment tools was given the highest rating among the approaches to meet the challenges faced by program directors.

Conclusions:

Program directors in otolaryngology do not have sufficient financial support, protected time, and personnel to fulfill their administrative and educational responsibilities. They should be provided with additional institutional assistance to help them achieve the goals of the Accreditation Council for Graduate Medical Education outcome project.
The etiology of otosclerosis: A combination of genes and environment
Authors: Schrauwen Isabelle , Van Camp Guy
Published: May 2010

Otosclerosis is a common form of hearing loss characterized by abnormal bone remodeling in the otic capsule. It is a complex genetic disease, caused by a combination of genetic and environmental factors. During the past decade, several attempts have been made to identify factors for otosclerosis. This review provides an overview of the current understanding of the etiology of otosclerosis and describes the genetic and environmental factors that have been implicated in the disease. Environmental factors include fluoride and viral factors, particularly measles. Genetic association studies for otosclerosis have reported several associations of genetic variants that influence the risk of disease, mainly involving bone remodeling pathways, although their individual risk contributions are small. Rare monogenic forms of otosclerosis also exist, which are caused by a mutation in a single gene leading to a clear familial segregation of the disease. Linkage analysis of large otosclerosis families has led to the identification of seven loci, and recently evidence was found that T cell receptor beta is a gene responsible for familial otosclerosis, suggesting an underlying immunological pathway. However, this might also represent an autoimmune process, a hypothesis that is supported by other data as well. In conclusion, a variety of pathways have been identified to be involved in the development of otosclerosis, showing that distinct mechanisms involving both genetic and environmental risk factors can influence and contribute to a similar disease outcome.
Automorphisms of endomorphism semigroups of reflexive digraphs
Authors: Araüjo João , Dobson Edward , Konieczny Janusz
Published: May 2010

A reflexive digraph is a pair (X, ρ), where X is an arbitrary set and ρ is a reflexive binary relation on X. Let End (X, ρ) be the semigroup of endomorphisms of (X, ρ). We determine the group of automorphisms of End (X, ρ) for: digraphs containing an edge not contained in a cycle, digraphs consisting of arbitrary unions of cycles such that cycles of length ≥2 are pairwise disjoint, and some circulant digraphs (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Group extensions and free actions by finite groups on solvmanifolds
Authors: Jo Jang Hyun , Lee Jong Bum
Published: May 2010

The purpose of this paper is to generalize Yalçin's result [Trans. Amer. Math. Soc. 352, 2689–2700 (2000)] from tori to solvmanifolds. As a result, we prove that if (ℤp)r acts freely on a solvmanifold M of dimension n, then r ≤ n (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Uniformly continuous superposition operators in the space of bounded variation functions
Authors: Matkowski Janusz
Published: May 2010

Let I, J ⊂ ℝ be intervals. The main result says that if a superposition operator H generated by a function of two variables h: I × J → ℝ,

H (φ)(x) ≔ h (x, φ (x)),

maps the set BV (I, J) of all bounded variation functions, φ: I → J into the Banach space BV (I, ℝ) and is uniformly continuous with respect to the BV ‐norm, then

h (x, y) = a (x)y + b (x), x ∈ I, y ∈ J,

for some a, b ∈ BV (I, ℝ) (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Members of the low‐density lipoprotein receptor‐related proteins provide a differential molecular signature between parental and CD133(+) DAOY medulloblastoma cells
Authors: Annabi Borhane , Doumit Jinane , Plouffe Karine , Laflamme Carl , Lord‐Dufour Simon , Béliveau Richard
Published: May 2010

Members of the low‐density lipoprotein receptor‐related protein (LRP) family are involved in metabolic stress and resistance phenotypes of cancer cells. New breakthroughs in brain cancer therapy have exploited that molecular signature and proved that efficient delivery of therapeutic agents involve LRP‐mediated mechanisms. We performed gene expression profiling of CD133, a cell surface cancer stem cell marker, and of LRP in response to in vitro nutrient deprivation. We found that CD133 was selectively induced in serum‐starved DAOY medulloblastoma cells but not in U87MG glioblastoma cells. Such CD133 induction was correlated to increases in LRP‐1 and LRP‐1b gene and protein expression. When a specific CD133(+) DAOY cell population was sorted from parental DAOY, we found increases in LRP‐5 and LRP‐8. Uptake of α2‐macroglobulin, a specific LRP‐1/1b ligand, was increased in serum‐starved parental DAOY cells but not in CD133(+) DAOY cells, and receptor‐associated protein (RAP), which binds to all cell surface LRPs, was able to compete for that uptake. Conversely, RAP binding was increased in serum‐starved parental DAOY but α2‐macroglobulin was unable to compete for such uptake. Strategies aiming at targeting cancer stem cell metabolic adaptative responses, such as that through LRP differential expression within the brain tissue microenvironmental niche, can now be envisioned. © 2010 Wiley‐Liss, Inc.
Synthesis and thermal behavior of a novel UV‐curable transparent flame retardant film and phosphorus‐nitrogen synergism of flame retardancy
Authors: Xing Weiyi , Song Lei , Jie Ganxin , Lv Xiaoqi , Wang Xin , Hu Yuan
Published: May 2010

A novel phosphorus monomer (PDHA) has been synthesized through phenyl dichlorophosphate (PDPC) reacting with 2‐hydroxyethyl acrylate (HEA). The structure of PDHA was characterized by Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance spectroscopy (1H NMR). A series of UV curable resins were manufactured by blending PDHA with triglycidyl isocyanurate acrylate (TGICA) at different weight ratios. The fire performance was examined by micro‐scale combustion calorimeter (MCC) and limiting oxygen index (LOI). The results obtained from MCC indicated that the addition of PDHA to TGICA reduced the HRR and HRC. In addition, the LOI values varied from 28 to 34. The char residues of the composites were observed by scanning electron microscopy (SEM). Their thermal degradation behavior was investigated by thermogravimetric analysis and real time FTIR analysis (RT‐FTIR). The test results indicated that when the weight ratio of PDHA/TGICA = 1:1, the onset temperature of the composite was highest and the most char residue at 700°C was observed. RT‐FTIR showed that the phosphate group of PDHA first degraded to form poly(phosphoric acid)s at around 300°C, which had the major contribution to form the compact char to protect the sample from further degradation. Copyright © 2010 John Wiley & Sons, Ltd.
Simultaneous determination of three naphthoquinones in the leaves ofImpatiens balsaminaL. by reversed‐phase high‐performance liquid chromatography
Authors: Sakunphueak Athip , Panichayupakaranant Pharkphoom
Published: May 2010

Introduction – Naphthoquinones; lawsone (1), lawsone methyl ether (2) and methylene‐3,3′‐bilawsone (3) are the main active compounds ofImpatiens balsaminaleaves.

Objective – To develop and validate an HPLC method for simultaneous quantitative determination of1–3inI. balsaminaleaf extracts.

Methodology – The method utilised a Supelco® C18column (5 µm, 4.6 × 150 mm) at 25°C with the mixture of 2% aqueous acetic acid : methanol (gradient elution as follows: 0–10 min, 25 : 75; 10–20 min, 32 : 68; 20–35 min, 55 : 45) as the mobile phase at a flow‐rate of 1 mL/min, and UV detection at 280 nm. The parameters of linearity, repeatability, reproducibility, accuracy specificity and sensitivity of the method were evaluated.

Results – The recovery of the method was 96–101% and linearity (r2≥ 0.9995) was obtained for all naphthoquinones. A high degree of specificity, as well as repeatability and reproducibility (RSD less than 5%), were also achieved. Copyright © 2010 John Wiley & Sons, Ltd.
Implementing Data Standards: A report on the HUPOPSI Workshop September 2009, Toronto, Canada
Authors: Orchard Sandra , Albar Juan‐Pablo , Deutsch Eric W. , Eisenacher Martin , Binz Pierre‐Alain , Hermjakob Henning
Published: May 2010

The plenary session of the Proteomics Standards Initiative of the Human Proteome Organisation at the 8th Annual HUPO World Congress updated the delegates on the current status of the ongoing work of this group. The mass spectrometry group reviewed the progress of mzML since its release last year and detailed new work on providing a common format for SRM/MRM transition lists (TraML). The implementation of mzIdentML, for describing the output of proteomics search engines, was outlined and the release of a new web service PSICQUIC, which allows users to simultaneously search multiple interaction databases, was announced. Finally, the audience participated in a lively debate, discussing both the benefits of these standard formats and issues with their adoption and use in a research environment.
HUPO Biological Reference Material Initiative Workshop 26 September 2009, Toronto, Canada
Authors: Nagy Judit M.
Published: May 2010

The Biological Reference Material Initiative Workshop held at the Toronto HUPO congress on 26 September 2009, focused on the development of new biological reference materials and tools for the assessment of reproducibility, the solutions to many of the technical challenges in proteomics and protein‐based molecular diagnostics. This half‐day meeting included presentations from leading scientists from the worldwide proteomic community, who shared a common interest in standardization and increased accuracy of proteomic data. The conclusion was that proteomics is highly sensitive to both biological and technical variability. It is this biological and technical variance, when not accounted for by experiment design, that invalidates proteomic experiments, but both of these issues can be dealt with by tackling reproducibility.
Burning Behavior of Nitramine Gun Propellants under the Influence of Pressure Oscillations
Authors: Pauly Gert , Scheibel Rudolf
Published: May 2010

By means of DNDA nitramine fractions in the formulation, it is hoped to produce gun propellants that have an almost temperature‐independent burning behavior. The reason for this behavior is not clear yet. In the last years, it has become known that pressure oscillations may occur in the hole channels of gun propellant grains that may lead to a modification of the burning. To analyze the impact of such oscillations on the burning behavior of DNDA powders, tests with two different DNDA powders were performed in a closed vessel. In both cases, it could be demonstrated that the oscillations have a determining influence on the temperature behavior.
F‐theory and unification
Authors: Wijnholt M.
Published: May 2010

We review some recent progress in Grand Unification using F‐theory.
Defects in highly Mg‐doped AlN
Authors: Nonaka Kentaro , Asai Toshiaki , Nagamatsu Kentaro , Iwaya Motoaki , Kamiyama Satoshi , Amano Hiroshi , Akasaki Isamu
Published: May 2010

Microstructural analysis was conducted to observe Mg‐related defects in highly Mg‐doped AlN on an undoped AlN layer grown by metalorganic vapor phase epitaxy. Pyramidal defects at a density of 1015 cm−3 were observed in the Mg‐doped AlN layer with a Mg concentration of 2.5 × 1019 cm−3. The size and density of the pyramidal defects decreased at a low Mg‐doped AlN layer with a Mg concentration. When the Mg concentration is high, defects of different shapes were formed in the Mg‐doped AlN layer.
A screened hybrid density functional study on energetic complexes: Metal carbohydrazide nitrates
Authors: Huang Huisheng , Zhang Tonglai , Zhang Jianguo , Wang Liqiong
Published: May 2010

The molecular geometry, electronic structure and thermochemistry of a series of metal carbohydrazide nitrates were investigated using the Heyd–Scuseria–Ernzerhof (HSE) screened hybrid density functional. The results show that Ca, Sr, and Ba complexes have additional coordinated oxygen atoms from the nitrate ion, which differ obviously from Cu, Ni, Co, and Mg complexes in terms of the geometric structure. Detailed NBO analyses clearly indicate that the metal–ligand interactions in Cu, Ni, and Co complexes are covalent, whereas those of Mg, Ca, Sr, and Ba complexes are ionic in nature. Furthermore, the donor–acceptor interactions result in a reduction of occupancies of σCO and σNH orbitals. Consequently, the bond lengths increase and the bond orders decrease. Finally, the calculated heats of formation predict that the ionic alkaline‐earth metal carbohydrazide nitrates are more stable than the covalent transition metal carbohydrazide nitrates. It agrees well with the available experimental thermal stabilities, indicating that the metal–ligand bonding character plays an important role in the stabilities of these energetic complexes. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A mechanism of the 1,3‐dipolar cycloaddition between the hydrogen nitryl HNO2 and acetylene HCCH: The electron localization function study on evolution of the chemical bonds
Authors: Berski Slawomir , Latajka Zdzislaw
Published: May 2010

The reaction between the simplest nitro compound HNO2 (hydrogen nitryl) and acetylene HCCH ‐ formally proceeding via 1,3‐dipolar cycloaddition ‐ has been studied by means of the B3LYP, MPW1K and MP2 methods. The energy barrier of 20.74 ÷ 32.91 kcal/mol is similar to ΔEa of the NNO + HCCH process but is essentially larger than computed for the reactions of HCCH with fulminic acid (HCNO) and NNCH2. Whole process is exothermic with the reaction energy: −10.87 ÷ −17.94 kcal/mol. An evolution of the chemical bonding has been analyzed by means of the Bonding Evolution Theory (BET) at the B3LYP/6‐31+G(d) and B3LYP/cc‐pVTZ levels. Two approximations of the reaction path have been considered, namely: the IRC and pseudo‐reaction paths. The reaction requires five steps and seven catastrophes of the fold and cusp type. A different effect of first fold catastrophe has been noticed. At the B3LYP/6‐31+G(d) level one of two nonbonding Vi=1,2(N) attractors is annihilated (F), meanwhile at B3LYP/cc‐pVTZ new V(N) attractor is created (F†). The chemical bonds are not formed/broken in TS. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A global search algorithm of minima exploration for the investigation of low lying isomers of clusters from DFT‐based potential energy surface. A theoretical study of Sin and Sin − 1Al clusters
Authors: Marchal Rémi , Carbonnière Philippe , Pouchan Claude
Published: May 2010

The first and most important step in the study of properties and dynamics of atomic and molecular clusters is the determination of their microscopic structures. We have developed a new algorithm (Marchal et al., J Chem Phys 2009, 131, 114105), called global search algorithm of minima exploration, which includes two original schemes: the spheroidal generation, allowing the generation of rings, spheres, m‐rings cylinders and planar structures, and the raking optimization process allowing to discard step by step the conformations that become physically unrealistic during the optimization process. Using such an algorithm, the microscopic structure of the well‐known silicon clusters have been revisited as a test case as well as the doped Sin−1Al ones. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Performance of 12 DFT functionals in the study of crystal systems: Al2SiO5 orthosilicates and Al hydroxides as a case study
Authors: Demichelis Raffaella , Civalleri Bartolomeo , D'Arco Philippe , Dovesi Roberto
Published: May 2010

The performance of 12 DFT functionals in describing the equilibrium structure and the relative stability of three Al2SiO5 orthosilicates (kyanite, andalusite and sillimanite) and four Al2O3 · nH2O hydroxides (diaspore, boehmite, gibbsite, and bayerite, with the last three systems being H‐bonded layered structures, HBLs) is assessed. Calculations were performed with the periodic ab initio CRYSTAL code by using all electron Gaussian‐type basis sets. The exchange‐correlation functionals tested are: Two LDA functionals (SVWN and PWLSD), five semilocal GGA functionals, both the standard ones tailored for molecules (PW and PBE) and the newly functionals devised for solids (PBEsol, SOGGA, and WC), and five hybrid functionals (B1WC, WC1LYP, B3LYP, B3PW, and PBE0). We find that recent GGA functionals for solids give similar results that are in between LDA and standard GGA functionals. They reproduce quite well the structure of Al2SiO5 polymorphs but fail for the H‐bonded layered Al hydroxides. The inclusion of HF exchange in the hybrid functionals leads to very good predicted structures for both systems. In particular, the structural parameters related to H atoms (OH and H···O distances, the lattice parameter along which the layers are stacked in HBLs) are remarkably improved with respect to the LDA and GGA functionals. Among the studied polymorphs, the correct order of stability is obtained with LDA and GGA functionals for solids, even if they overstabilize denser phases. Standard GGA and hybrids reduce the range of stability but they are often unsatisfactory in reproducing the correct order of stability. This is particularly relevant for the B3LYP functionals. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Continuum, discrete, and explicit solvation models for describing the low‐lying absorption spectrum of the pterin acid in aqueous environment
Authors: Jaramillo Paula , Coutinho Kaline , Canuto Sylvio
Published: May 2010

The absorption spectrum of the acid form of pterin in water was investigated theoretically. Different procedures using continuum, discrete, and explicit models were used to include the solvation effect on the absorption spectrum, characterized by two bands. The discrete and explicit models used Monte Carlo simulation to generate the liquid structure and time‐dependent density functional theory (B3LYP/6‐31G+(d)) to obtain the excitation energies. The discrete model failed to give the correct qualitative effect on the second absorption band. The continuum model, in turn, has given a correct qualitative picture and a semiquantitative description. The explicit use of 29 solvent molecules, forming a hydration shell of 6 Å, embedded in the electrostatic field of the remaining solvent molecules, gives absorption transitions at 3.67 and 4.59 eV in excellent agreement with the S0–S1 and S0–S2 absorption bands at of 3.66 and 4.59 eV, respectively, that characterize the experimental spectrum of pterin in water environment. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2371–2377, 2010
A DFT study on molecular junction devices with cyclic disulfide anchors: Effect of anchor oxidation on electron transport
Authors: Jang Yun Hee
Published: May 2010

A molecular‐scale electronic device can be built with programmable molecular switches sandwiched between two electrodes. A cyclic disulfide, 1,2‐dithiolane, is a promising anchor group for attaching molecules to gold electrodes in such molecular junction devices, since its dithiol–Au linkage (with the disulfide bond broken) can provide added stabilities and reduced current fluctuations. However, operations of the molecular switches under redox conditions might lead to redox processes involving the AuS bonds at the contact. Formation of the disulfide linkage can be induced, and the dithiolate group (AuS) can be converted into disulfoxide (AuSO) or disulfone (AuSO2) groups. Coexistence of these various oxidation states at the contact or the conversion between them can be a potential source of current fluctuation in the junction. However, our nonequilibrium Green's function calculations combined with the density functional theory show that the molecular junctions with different oxidation states of the 1,2‐dithiolane alligator clips to two gold electrodes exhibit essentially the same insulating current–voltage characteristics at moderate bias voltages. Therefore, the robustness of the molecular junctions would not be affected by the state change of the disulfide alligator clips at the contact. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Analytical energy gradients of Coulomb‐attenuated time‐dependent density functional methods for excited states
Authors: Nguyen Kiet A. , Day Paul N. , Pachter Ruth
Published: May 2010

We present an implementation and validation of the analytical energy gradient of time‐dependent density functional theory (TDDFT) using Coulomb‐attenuated (CA) functionals for excited state energies, dipole moments, geometries, and vibrational frequencies. The CA‐TDDFT gradient is based on the previous long‐range corrected TDDFT of (Chiba et al. J Chem Phys 2006, 124, 144106) and the Z‐vector formalism of (Furche and Ahlrichs J Chem Phys 2002, 117, 7433). Geometry optimization using CA‐TDDFT was carried out for molecules (substituted stilbenes and coumarins) having intramolecular charge‐transfer excited states and for a series of small molecules (CO, HCN, CH2O, CH2S, CCl2, C2H2, trans‐(CHO)2). We assess the results of the CA functionals, the long‐range corrected LC‐BLYP functional, and the B3LYP hybrid functional, by comparing to accurate experimental data. The results highlight the applicabilty of different functionals for excited state properties. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Entropy–energy balance in base catalyzed keto‐enol interconversion: A joint theoretical and experimental investigation
Authors: Aschi Massimiliano , Zappacosta Romina , DE Maria Paolo , Siani Gabriella , Fontana Antonella , Amadei Andrea
Published: May 2010

The mechanism of base catalyzed keto‐enol interconversion of aqueous 2‐phenylacetylthiophene has been investigated by a joint application of experimental and computational approaches. Primarily we have focused our attention on the water‐enolate proton transfer representing the rate determining step of the reaction. Computational results, in good agreement with experimental data demonstrate the crucial role exerted by the solvent. In particular, beyond the bulk catalytic effect an explicit assistance of solvent molecules allows the reaction to increase its efficiency. A combination on Molecular Dynamics simulations and Perturbed Matrix Method calculations also highlight the subtle balance between energetic and entropic effects which characterize the mechanistic scenario. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Gödelian structures and self‐organization in biological systems
Authors: Brändas Erkki J.
Published: May 2010

In 1986, Seel and Ladik asked, which role Gödel's incompleteness theorem should have in a basic theory of biology. Recently, the author has tried to collect the conditions, which such a meta‐theory must fulfill. A further argument concerned the deeper connection between classical canonical forms of so‐called (triangular) Jordan blocks in the description of open quantal systems far from equilibrium and those of self‐referential contradictions and paradoxes in philosophy and mathematical logic. Related examples were quoted from the emergence of self‐organization in so‐called dissipative structures with applications to both fundamental‐ and of higher order levels of organization. To bring this analogy closer together, we have developed a quantum logical formalism, describing such a Gödelian situation, via the characterization of a well‐defined “truth matrix.” In this setting, the modus operandi of exploiting self‐referential traits and paradoxical inconsistencies emphasize the possibility of a meta‐code in complicated enough (biological) systems. In conclusion, we will revisit situations were the aforementioned self‐referential property, together with the laws of physics and chemistry will guide our understanding of biology. We will finally consider subsequent implications on the various positions on artificial intelligence. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
The quantum divided basins: A new class of quantum subsystems
Authors: Heidarzadeh Farnaz , Shahbazian Shant
Published: May 2010

The rigorous theory of the quantum divided basins (QDB), the quantum subsystems emerging from the net zero‐flux equation, is considered in this article. This framework, the quantum theory of proper open subsystems, is derived from the extension of the quantum theory of atoms in molecules to encompass the new class of quantum subsystems. It is demonstrated that the regional hypervirial theorem and the associated regional observables as well as the subsystem variational procedure are all expressible for the QDB. The history of QDB is briefly reviewed and the bundles, which were introduced by other researchers, are offered as typical examples whereas new examples of QDB (not yet mentioned in literature) are also presented. Based on some model systems as well as the nitrogen molecule, the regional properties and the morphologies of typical QDB are scrutinized. It is also demonstrated that the QDB may be used to study the fine structure of the electron localization and delocalization. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
A computational study of the absorption spectra of 1‐substituted phenyl‐3,5‐diphenylformazans
Authors: Tezcan Habi̇be , Tokay Nesri̇n
Published: May 2010

In this study, the ground‐state geometries and absorption wavelengths of 1‐substituted (NO2, COOH) phenyl‐3,5‐diphenylformazans have been determined with density functional theory (DFT) and time‐dependent DFT (TD‐DFT) by combining polarizable continuum model. The calculations were carried out by using PBE1PBE functional with four basis sets to determine the λmax of the UV–visible (UV–vis) spectra for the studied formazans. Comparison of experimental and theoretical results showed that λmax of the UV–vis spectra could be reproduced by TD‐DFT. The effects of chemical substitution on the UV–vis spectra were analyzed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Checking the validity of the vorticity expansion approximation of the current‐density functional theory
Authors: Higuchi Katsuhiko , Miyasita Mitiyasu , Higuchi Masahiko
Published: May 2010

Four kinds of asymptotic bounds for the exchange‐correlation (XC) energy functional of the current‐density functional theory (CDFT) are derived by using both the coordinate scaling of electrons and the adiabatic connection. These asymptotic bounds are effectively used to check the validity of the approximate form of the exchange‐correlation energy functional of the CDFT. It is found that the vorticity expansion approximation (VEA) formula, which has recently been proposed by us, exactly satisfies all asymptotic bounds, though the local density approximation of the CDFT does not satisfy two of four asymptotic bounds. The validity of the VEA formula is thus confirmed successfully. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Impact of the ionic forms on the UV–Vis spectra 2‐hydroxybenzylamine. A TD‐DFT study
Authors: Adrover Miquel , Frau Juan , Caldés Catalina , Vilanova Bartolomé , Donoso Josefa , Muñoz Francisco
Published: May 2010

PCM‐TD‐DFT computations were used to examine the electronic transitions exhibited by the molecular species of 2‐hydroxybenzylamine (2‐BNZ). The theoretical results thus obtained were found to accurately fit their experimental counterparts and to afford the assignation of the different experimental electronic transitions to 2‐BNZ tautomers present in the solution. Also, the HCTH functional was found to accurately reproduce electronic excitations in the cationic species and neutral tautomer, and the B3LYP functional to provide accurate predictions of the transitions for the anionic species and zwitterionic tautomer. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Preventive doping control screening analysis of prohibited substances in human urine using rapid‐resolution liquid chromatography/high‐resolution time‐of‐flight mass spectrometry
Authors: Vonaparti A. , Lyris E. , Angelis Y. S. , Panderi I. , Koupparis M. , Tsantili‐Kakoulidou A. , Peters R. J. B. , Nielen M.W.F. , Georgakopoulos C.
Published: May 2010

Unification of the screening protocols for a wide range of doping agents has become an important issue for doping control laboratories. This study presents the development and validation of a generic liquid chromatography/time‐of‐flight mass spectrometry (LC/TOFMS) screening method of 241 small molecule analytes from various categories of prohibited substances (stimulants, narcotics, diuretics, β2‐agonists, β‐blockers, hormone antagonists and modulators, glucocorticosteroids and anabolic agents). It is based on a single‐step liquid‐liquid extraction of hydrolyzed urine and the use of a rapid‐resolution liquid chromatography/high‐resolution time‐of‐flight mass spectrometric system acquiring continuous full scan data. Electrospray ionization in the positive mode was used. Validation parameters consisted of identification capability, limit of detection, specificity, ion suppression, extraction recovery, repeatability and mass accuracy. Detection criteria were established on the basis of retention time reproducibility and mass accuracy. The suitability of the methodology for doping control was demonstrated with positive urine samples. The preventive role of the method was proved by the case where full scan acquisition with accurate mass measurement allowed the retrospective reprocessing of acquired data from past doping control samples for the detection of a designer drug, the stimulant 4‐methyl‐2‐hexanamine, which resulted in re‐reporting a number of stored samples as positives for this particular substance, when, initially, they had been reported as negatives. Copyright © 2010 John Wiley & Sons, Ltd.
Sparse partial least squares regression for on‐line variable selection with multivariate data streams
Authors: McWilliams Brian , Montana Giovanni
Published: May 2010

Data streams arise in several domains. For instance, in computational finance, several statistical applications revolve around the real‐time discovery of associations between a very large number of co‐evolving data feeds representing asset prices. The problem we tackle in this paper consists of learning a linear regression function from multivariate input and output streaming data in an incremental fashion while also performing dimensionality reduction and variable selection. When input and output streams are high‐dimensional and correlated, it is plausible to assume the existence of hidden factors that explain a large proportion of the covariance between them. The methods we propose build on recursive partial least squares (PLS) regression. The hidden factors are dynamically inferred and tracked over time and, within each factor, the most important streams are recursively identified by means of sparse matrix decompositions. Moreover, the recursive regression model is able to adapt to sudden changes in the data generating mechanism and also identifies the number of latent factors. Extensive simulation results illustrate how the methods perform and compare with alternative penalized regression models for streaming data. We also apply the algorithm to solve a multivariate version of theenhanced index trackingproblem in computational finance. Copyright © 2010 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 3: 170‐193, 2010
Online training on a budget of support vector machines using twin prototypes
Authors: Wang Zhuang , Vucetic Slobodan
Published: May 2010

This paper proposes twin prototype support vector machine (TVM), a constant space and sublinear time support vector machine (SVM) algorithm for online learning. TVM achieves its favorable scaling by memorizing only a fixed‐size data summary in the form of example prototypes and their associated information during training. In addition, TVM guarantees that the optimal SVM solution is maintained on all prototypes at any time. To maximize the accuracy of TVM, prototypes are constructed to approximate the data distribution near the decision boundary. Given a new training example, TVM is updated in three steps. First, the new example is added as a new prototype if it is near the decision boundary. If this happens, to maintain the budget, either the prototype farthest away from the decision boundary is removed or two near prototypes are selected and merged into a single one. Finally, TVM is updated by incremental and decremental techniques to account for the change. Several methods for prototype merging were proposed and experimentally evaluated. TVM algorithms with hinge loss and ramp loss were implemented and thoroughly tested on 12 large datasets. In most cases, the accuracy of low‐budget TVMs was comparable with the resource‐unconstrained SVMs. Additionally, the TVM accuracy was substantially larger than that of SVM trained on a random sample of the same size. Even larger difference in accuracy was observed when comparing with Forgetron, a popular budgeted kernel perceptron algorithm. As expected, the difference in accuracy between hinge loss and ramp loss TVM was negligible and hinge loss version is preferable due to its lower computational cost. The results illustrate that highly accurate online SVMs could be trained from arbitrary large data streams using devices with severely limited memory budgets. Copyright © 2010 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 3: 149‐169, 2010
Antimony biomethylation in culture media revisited in the light of solubility and chemical speciation considerations
Authors: Filella Montserrat , Williams Peter A.
Published: May 2010

Laboratory culture experiments have shown that antimony biomethylation can result from bacterial and fungal activity under both aerobic and anaerobic conditions. However, in the light of our current knowledge of antimony solubility and equilibria, critical analysis of the conditions used in published laboratory studies reveals that solution chemistry was generally overlooked and oversaturated solutions were used. As a result, it is very difficult, if not impossible, to establish reliable observed effect‐concentration relationships in the experiments published. © 2010 Wiley Periodicals, Inc. Environ Toxicol 2010.
Two‐mode limited feedback block‐fading adaptive transmission with minimum guaranteed rate in MIMO channel
Authors: Knize Milan , Sykora Jan
Published: May 2010

This paper develops an adaptive scheme relying on a part‐time availability of the channel state information and supplying the constant minimum rate achievable for an arbitrary fading realization. The two‐mode transmission is investigated with the instantaneous perfect channel state information being known at the transmitter in the limited portion of time. We derived a general procedure for a suitable probabilistic description of the channel under such a scheme. The first mode is without any feedback and it uses a simple uniform symbol energy assignment. The second one is the emergency mode with the perfect instantaneous channel state information. It is implemented by the channel inversion (or eigenmode sub‐space channel inversion) guaranteeing the minimum required rate regardless of the channel observation. The parameters of the transmission are the total available transmitted symbol energy, the portion of time the perfect feedback channel is used, the minimum required rate, and the average symbol energy transmitted in the first and the second mode. For these cases, we have found very essential trade‐off among the system parameters and also we have derived a general procedure how to evaluate long‐term performance. Copyright © 2010 John Wiley & Sons, Ltd.
Computational social science
Authors: Cioffi‐Revilla Claudio
Published: May 2010

The social sciences investigate human and social dynamics and organization at all levels of analysis (consilience), including cognition, decision making, behavior, groups, organizations, societies, and the world system. Computational social science is the integrated, interdisciplinary pursuit of social inquiry with emphasis on information processing and through the medium of advanced computation. The main computational social science areas are automated information extraction systems, social network analysis, social geographic information systems (GIS), complexity modeling, and social simulation models. Just like Galileo exploited the telescope as the key instrument for observing and gaining a deeper and empirically truthful understanding of the physical universe, computational social scientists are learning to exploit the advanced and increasingly powerful instruments of computation to see beyond the visible spectrum of more traditional disciplinary analyses. Copyright © 2010 John Wiley & Sons, Inc.

This article is categorized under:

Data: Types and Structure > Social Networks
Synthesis, Structure and Magnetic Properties of dimeric Nickel(II) Benzoate with Pyridyl‐substituted Nitronyl Nitroxides
Authors: Zhu Lili , Chen Xiaodan , Zhao Qihua , Li Zhongshu , Zhang Xiangyang , Sun Baiwang
Published: May 2010

The novel heterospin complex [Ni2(PhCOO)4(NITpPy)2]·2CH3CN (1) was synthesized by the reaction of nickel benzoate and 2‐(4‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide (NITpPy) in acetonitrile and dichloromethane solutions. The X‐ray structure determination shows that complex 1 consists of a symmetrical dimeric NiII benzoate paddle‐wheel core and pyridyl nitrogen atoms of radical ligands at the apical position, in addition, the temperature (2–300K) dependent magnetic susceptibility measurements indicate that 1 has antiferromagnetic behavior.
Local well‐posedness of the viscous rotating shallow water equations with a term of capillarity
Authors: Wu G. , Zhang B.
Published: May 2010

Making use of the Fourier localization method, we prove the local‐in‐time existence and uniqueness of solutions to the viscous rotating shallow water equations with a term of capillarity under both the low regularity assumption on the initial data and the assumption that the initial height is bounded away from zero.
The rounded triangular cross section – Exact solutions for torsion, flow and heat transfer
Authors: Wang C.Y.
Published: May 2010

Exact solutions for the torsion of a bar, flow, and heat transfer in a duct, all having rounded triangular cross sections, are presented. The family of shapes has the circle and the equilateral triangle as extreme cases. Geometrical properties, torsional rigidity, flow rates, and Nusselt numbers are determined.
Novel photodynamic therapy against biliary tract carcinoma using mono‐l‐aspartyl chlorine e6: basic evaluation for its feasibility and efficacy
Authors: Kasuya Kazuhiko , Shimazu Motohide , Suzuki Minako , Kuroiwa Yukari , Usuda Jitsuo , Itoi Takao , Tsuchida Akihiko , Aoki Tatsuya
Published: May 2010

Background

Recently, a second‐generation photosensory agent for photodynamic therapy (PDT), mono‐l‐aspartyl chlorine e6 (NPe6), which degrades rapidly in vivo, has been developed. We evaluated its feasibility and efficacy for treatment in biliary tract carcinoma.

Methods

A transmittance of semiconductor laser light (664 nm), sensitivity of a human biliary tract carcinoma cell line, and disorder to normal tissue including Glissonian constructs and adjacent hepatocytes were investigated.

Results

The transmittance of the laser was 85‐91% through yellow clear bile and that of the bile including 50 μg/ml NPe6 was 17–48%. The effective concentration of NPe6 which showed LD50 for a cell line was 12.5 μg/ml, and that of LD95 was 25 μg/ml. NPe6 in the supernatant reduced laser transmissiveness, but it had little influence on the antitumor effect in supernatant with or without NPe6. The NOZ cell‐tumor volume was reduced significantly 14 days after irradiation in the PDT group (PDT 69.9 ± 44.6 mm3 vs control 296.3 ± 239.9 mm3
P < 0.05). No severe hepatic disorder including Glisson components was observed by the histological findings.

Conclusion

NPe6 PDT was effective in carcinomas even in the presence of bile, and causes no serious complication for the liver and Glisson structure. Therefore, NPe6 PDT will be a useful candidate as a new therapy for biliary tract carcinomas.
Exogenous melatonin treatment reduces hepatocyte damage in rats with experimental acute pancreatitis
Authors: Çöl Cavit , Dinler Kahraman , Hasdemir Oğuz , Büyükaşık Oktay , Buğdaycı Güler , Terzi Hakan
Published: May 2010

Background/purpose

The hormone melatonin affects cellular immunity in particular and the immune system in general both directly and indirectly. We report our evaluation of the effects of decreasing and increasing serum melatonin levels on hepatocyte damage in rats with experimental acute pancreatitis.

Methods

Winstar Albino rats with experimentally induced acute pancreatitis were divided into three groups of ten rats each: (1) control (induced acute pancreatitis only); (2) rats with induced acute pancreatitis plus surgical pinealectomy (no melatonin injections); (3) rats with induced acute pancreatitis plus injections of exogenous melatonin. The effects of melatonin levels were evaluated using biochemical and histopathological parameters.

Results

Rats undergoing the pinealectomy had increased amylase and lactate dehydrogenase (LDH) levels, while those receiving injections of exogenous melatonin had decreased amylase, aspartate transaminase, LDH, and bilirubin levels but increased levels of alanine transferase levels.

Conclusion

Melatonin may have a therapeutic or protective effect on acute pancreatitis and obstructive jaundice.