bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cathodoluminescence of SiOx under‐stoichiometric silica layers
Authors: Salh Roushdey , von Czarnowski A. , Zamoryanskaya M. V. , Kolesnikova E. V. , Fitting H.‐J. 
Published: April 2006

AbstractUnder‐stoichiometric thin silica layers SiOx with different stoichiometric degree 1 ≤ x ≤ 2, were prepared by thermal evaporation of silicon monoxide in vacuum and in ambient oxygen atmosphere of various pressure onto crystalline silicon substrates. The chemical composition has been determined by Fourier transform infrared spectroscopy (FTIR). A special formula is derived to correlate the stoichiometric degree x with the wavenumber of the main TO stretching mode (Si–O–Si) in silica, finally to determine the actual composition values x of the layers. Cathodoluminescence (CL) of these layers shows the development of typical amorphous SiO2 luminescence bands at the composition threshold x > 1.5 and then onwards to x = 2. These luminescence bands were observed at 4.3, 2.7, 2.15, and 1.9 eV. The green–yellow luminescence (2.15 eV) is strongly increasing with the annealing temperature up to 1300 °C and is assigned to phase separation of SiOx into Si and SiO2 and formation of hexamer silicon rings in the understoichiometric silica network. Finally we observe Si nanoclusters by means of transmission elec‐ tron microscopy (TEM) micrographs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
EPR study of the structural phase transitions in Fe3+ doped TlInS2
Authors: Mikailov F. A. , Kazan S. , Rameev B. Z. , Acikgoz M. , Aktaş B. 
Published: April 2006

AbstractThe results of low temperature EPR investigations of Fe doped TlInS2 single crystals in the temperature range 5–300 K are presented. The EPR signal due to Fe3+ centers located at the centers of InS4 tetrahedrons has been observed. It has been established that the resonance lines exhibit a slight shift and remarkable splitting at the temperatures lower than 200 K, which is attributed to the effect of the ferroelectric phase transition. The rotational patterns of the resonance fields reveal a doubling of the number of centers at low temperatures. The preliminary simulation indicates that the doubling is related to the rotation of the principal axis system of the centers, while the magnitude of fine structure splitting is nearly the same. ( © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Six Sigma Literature: A Review and Agenda for Future Research
Authors: Brady James E. , Allen Theodore T. 
Published: April 2006

AbstractLike quality management in general, Six Sigma has penetrated into most sectors of today's business world. Although Six Sigma originated in industry, it has inspired a considerable amount of academic literature. This paper reviews this literature describing the trends, sources, and findings. The paper also seeks to synthesize the literature, with an emphasis on establishing its relationship to quality management theory and topics for future research. In doing so, there is an attempt to answer the following fundamental questions. (i) What is Six Sigma? (ii) What are its impacts on operational performance? (iii) What roles can academics usefully play in relation to Six Sigma? Copyright © 2006 John Wiley & Sons, Ltd.
Fraction of Design Space Plots for Split‐plot Designs
Authors: Liang Li , Anderson‐Cook Christine M. , Robinson Timothy J. 
Published: April 2006

AbstractIn industrial experiments, restrictions on the execution of the experimental runs or the existence of one or more hard‐to‐change factors often leads to split‐plot experiments, where there are two types of experimental units and two independent randomizations. The resulting compound symmetric error structure, as well as the settings of whole‐plot and subplot factors, play important roles in the performance of split‐plot experiments. When the practitioner is interested in predicting the response, a response surface design for a second‐order model such as a central composite design (CCD) is often used. The prediction variance of second‐order designs under a split‐plot error structure is often of interest. In this paper, fraction of design space (FDS) plots are adapted to split‐plot designs. In addition to the global curve exploring the entire design space, sliced curves at various whole‐plot levels are presented to study prediction performance for subregions in the design space. The different sizes of the constrained subregions are accounted for by the proportional size of the sliced curves. The construction and use of the FDS plots are demonstrated through two examples of the restricted CCD in split‐plot schemes. We also consider the impact of the variance ratio on design performance. Copyright © 2006 John Wiley & Sons, Ltd.
Classes of Split‐plot Response Surface Designs for Equivalent Estimation
Authors: Parker Peter A. , Kowalski Scott M. , Vining G. Geoffrey 
Published: April 2006

AbstractWhen planning an experimental investigation, we are frequently faced with factors that are difficult or time consuming to manipulate, thereby making complete randomization impractical. A split‐plot structure differentiates between the experimental units associated with these hard‐to‐change factors and those that are relatively easy‐to‐change. Furthermore, it provides an efficient strategy that integrates the restrictions imposed by the experimental apparatus into the design structure. In this paper, several industrial and scientific examples are presented to highlight design considerations when a restriction on randomization is encountered. We propose classes of split‐plot response designs that provide an intuitive and natural extension from the completely randomized context. For these designs, the ordinary least‐squares estimates of the model are equivalent to the generalized least‐squares estimates. This property provides best linear unbiased estimators and simplifies model estimation. The design conditions that provide equivalent estimation are presented and lead to design construction strategies to transform completely randomized Box–Behnken, equiradial and small composite designs into a split‐plot structure. Published in 2006 by John Wiley & Sons, Ltd.
New approach using the relativistic Hamilton–Jacobi equation to evaluate the correct energy levels for the hydrogen atom
Authors: Nascimento D. L. , Fonseca A. L. A. 
Published: April 2006

AbstractThe aim of the present study is to propose a model based on classical field theory to study atomic and molecular systems. Starting from the basic principles of the special relativity theory (SRT), the model is described by taking the interaction between two moving particles with the standing wave radiated from the particles in the four‐dimensional space–time. According to the classical theory of fields, the geometrical properties of the solutions are governed by a classical‐like equation of motion. An eigenvalue equation is derived from an improvement of the relativistic variational method introduced by Schrödinger in 1926 1. This formalism is applied to the standard hydrogen atom problem, yielding solutions of the equation of motion by integrals of action and by solving the associated differential eigenvalue equation. Both sets of solutions reproduce the correct fine structure of the energy levels. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
First hyperpolarizabilities of vinylogue organometallic sesquifulvalene chromophores: A DFT study
Authors: Mang Chaoyong , Wu Kechen 
Published: April 2006

AbstractStatic first hyperpolarizabilities of vinylogue mono‐ and bimetallic sesquifulvalene chromophores, [(η5‐C5H5)M{μ−(η5‐C5H4)CHCH(η6‐C7H7)}]+ (M = Fe, Ru, and Os) and [(η5−C5H5)M{μ−(η5‐C5H4)CHCH(η6‐C7H7)}Cr(CO)3]+ (M = Fe, Ru, and Os) have been calculated within DFT theoretical approach. The results agree well with the recent Hyper‐Rayleigh scattering (HRS) measurements. The coordinated transition metals reduced the magnitude of dipole moment and first hyperpolarizability. The metal‐to‐ligand charge‐transfer contributes to the first hyperpolarizability and, as a result, the rational substitution of coordinated metal could modulate the first hyperpolarizability of the organometallic chromophores. The study would be helpful to understand optical nonlinearities in organometallic complexes. © 2006 Wlley Periodicals, Inc. Int J Quantum Chem, 2006
An analysis of complex multiple‐choice science–technology–society items: Methodological development and preliminary results
Authors: Vázquez‐Alonso Ángel , Manassero‐Mas María‐Antonia , Acevedo‐Díaz José‐Antonio 
Published: April 2006

AbstractThe scarce attention to the assessment and evaluation in science education research has been especially harmful for teaching science–technology–society (STS) issues, due to the dialectical, tentative, value‐laden, and polemic nature of most STS topics. This paper tackles the methodological difficulties of the instruments that monitor views related to STS topics and rationalizes a quantitative methodology and an analysis technique to improve the utility of an empirically developed multiple‐choice item pool, the Questionnaire of Opinions on STS. This methodology embraces an item‐scaling psychometrics based on the judgments by a panel of experts, a multiple response model, a scoring system, and the data analysis. The methodology finally produces normalized attitudinal indices that represent the respondent's reasoned beliefs toward STS statements, the respondent's position on an item that comprises several statements, or the respondent's position on an entire STS topic that encompasses a set of items. Some preliminary results show the methodology's ability to evaluate the STS attitudes in a qualitative and quantitative way and for statistical hypothesis testing. Lastly, some applications for teacher training and STS curriculum development in science classrooms are discussed. © 2006 Wiley Periodicals, Inc. Sci Ed 90:681–706, 2006
A natural history model of stage progression applied to breast cancer
Authors: Plevritis Sylvia K. , Salzman Peter , Sigal Bronislava M. , Glynn Peter W. 
Published: April 2006

AbstractInvasive breast cancer is commonly staged as local, regional or distant disease. We present a stochastic model of the natural history of invasive breast cancer that quantifies (1) the relative rate that the disease transitions from the local, regional to distant stages, (2) the tumour volume at the stage transitions and (3) the impact of symptom‐prompted detection on the tumour size and stage of invasive breast cancer in a population not screened by mammography. By symptom‐prompted detection, we refer to tumour detection that results when symptoms appear that prompt the patient to seek clinical care. The model assumes exponential tumour growth and volume‐dependent hazard functions for the times to symptomatic detection and stage transitions. Maximum likelihood parameter estimates are obtained based on SEER data on the tumour size and stage of invasive breast cancer from patients who were symptomatically detected in the absence of screening mammography. Our results indicate that the rate of symptom‐prompted detection is similar to the rate of transition from the local to regional stage and an order of magnitude larger than the rate of transition from the regional to distant stage. We demonstrate that, in the even absence of screening mammography, symptom‐prompted detection has a large effect on reducing the occurrence of distant staged disease at initial diagnosis. Copyright © 2006 John Wiley & Sons, Ltd.
A unimodal curve for primate group size along a gradient of population density
Authors: Horiuchi Shiro 
Published: April 2006

AbstractWhen plotted along a gradient of population density, the mean group size in populations of several primate species has a unimodal distribution, i.e., mean group size is greater at intermediate population densities than at higher or lower population densities. In this study I present a mathematical model to clarify the cause of this relationship. Population density is assumed to affect group size by enhancing between‐ or within‐group competition and by changing the number of neighboring groups around each group. The mean group size is predicted to decline as population density increases above a critical value, owing to the increasing number of neighboring groups.
Vitamin B12 and vitamin B6 supplementation is needed among adults with phenylketonuria (PKU)
Authors: Hvas A. M. , Nexo E. , Nielsen J. B. 
Published: April 2006

SummaryPhenylketonuria (PKU) is caused by an autosomal recessive deficiency of the enzyme phelnylalanine hydroxylase leading to a failure to convert phenylalanine to tyrosine. To avoid irreversible neurological damage because of increased phenylalanine, treatment is instituted rapidly after birth. We examined 31 adult PKU patients living on a less protein‐restricted diet. Theoretically, these PKU patients had an increased risk of developing vitamin B12 and B6 deficiency because of a limited intake of animal products. Besides laboratory tests (n = 31) we obtained clinical information (n = 30) and detailed information on food consumption (n = 28). Three‐quarters of the patients had early biochemical signs of vitamin B12 deficiency. In spite of a normal folate status, 9 (29%) had a plasma homocysteine above 12 μmol/L. In accord with these findings, the food questionnaires indicated that 11 (39%) patients received less than the recommended daily vitamin B12, and 20 (71%) received less vitamin B6 than recommended. A significant association was found between reduced vitamin B12 intake and both reduced serum cobalamins (p = 0.04) and reduced serum transcobalamin saturation (p = 0.03). Eleven patients took a vitamin pill daily, and these patients had a significantly lower plasma homocysteine compared to the rest. The present study suggests that adult PKU patients were at increased risk of developing vitamin B12 deficiency, and their intake of vitamin B6 was below the recommended daily intake. In conclusion PKU patients need continuing dietary guidance throughout adult life, and considering the risks, costs and potential benefits, daily vitamin supplementation seems justified in these patients.
A study on the nature of genetic metabolic practice at a major paediatric referral centre
Authors: Glass H. C. , Feigenbaum A. , Clarke J. T. R. 
Published: April 2006

SummaryA retrospective chart review of new paediatric patients seen during the calendar year 1998 by specialists of the Division of Clinical and Metabolic Genetics of the Hospital for Sick Children in Toronto, the largest such referral centre in the country, showed that 81% of specific genetic metabolic diagnoses were made within one month of being seen in consultation by one of the consultants of the programme. In 5% of cases, a specific diagnosis was not reached 4 years after initial consultation. We concluded from this study that the specific diagnosis of inborn errors of metabolism at a major medical genetic referral centre tended to be made quickly, or never. Some of the causes of delays in diagnosis include (1) the lack of ready access to existing diagnostic laboratory testing; (2) technical barriers to the identification of specific metabolic or genetic defects; and (3) incomplete knowledge of genetic defects causing inherited metabolic diseases.
Enzyme replacement therapy and bony changes in Egyptian paediatric Gaucher disease patients
Authors: El‐Beshlawy A. , Ragab L. , Youssry I. , Yakout K. , El‐Kiki H. , Eid K. , Mansour I. M. , El‐Hamid S. Abd , Yang M. , Mistry P. K. 
Published: April 2006

SummaryBackground. In Gaucher disease, the infiltration of the bone marrow by glucocerebroside‐laden macrophages (Gaucher cells) triggers a diverse pattern of skeletal disease that results in crippling complications. Reliable ascertainment of the severity and pattern of skeletal disease is essential to determine disease status and the response to enzyme replacement therapy (ERT). Although there is ample documentation of reversal of haematological and visceral disease by ERT, there is a paucity of data on skeletal response to ERT in children.Aim. To delineate the pattern of bone disease in children with Gaucher disease in Egypt and to evaluate its response to ERT.Method. Twenty‐two children with Gaucher disease were treated with ERT. Phenotyping by clinical, laboratory and radiological criteria was performed at baseline and following 11.2 ± 4 months of ERT. Genotyping for glucocerebrosidase (GBA) mutations was performed by gene sequencing, and genotype–phenotype correlations were performed.Results. Two‐thirds of the patients were from consanguineous pedigrees and 14/22 patients were homozygous or compound heterozygous for L444P and D409H mutations. Bone involvement was detected by plain radiology in 11 children (50%) and in 16 (73%) by magnetic resonance imaging (MRI). There was no correlation of severity of bone involvement and GBA genotype. ERT ameliorated bone disease: 10 of the 11 children with abnormal radiographic findings at baseline showed improvement in skeletal lesions; while 9/16 showed improvement of marrow disease by MRI. Radiographic sensitivity and specificity were 62% and 82% compared to MRI for detection of bone involvement in this patient population. At baseline, bone pain was present in 5 patients and ERT resulted in complete symptomatic remission in all of them. ERT was associated with significant improvement in growth parameters and amelioration of haematological and visceral involvement.Conclusion. Symptomatic and radiological skeletal disease is common in children with Gaucher disease in Egypt. MRI is the most accurate technique for detecting early skeletal involvement. There was no correlation between severity of skeletal involvement and GBA genotype. ERT was effective in ameliorating radiological manifestations of skeletal disease and achieving complete remission of bone pain.
X‐linked creatine transporter defect: A report on two unrelated boys with a severe clinical phenotype
Authors: Anselm I. M. , Alkuraya F. S. , Salomons G. S. , Jakobs C. , Fulton A. B. , Mazumdar M. , Rivkin M. , Frye R. , Poussaint T. Young , Marsden D. 
Published: April 2006

SummaryWe report two unrelated boys with the X‐linked creatine transporter defect (CRTR) and clinical features more severe than those previously described with this disorder. These two boys presented at ages 12 and 30 months with severe mental retardation, absent speech development, hypotonia, myopathy and extra‐pyramidal movement disorder. One boy has seizures and some dysmorphic features; he also has evidence of an oxidative phosphorylation defect. They both had classical absence of creatine peak on brain magnetic resonance spectroscopy (MRS). In one, however, this critical finding was overlooked in the initial interpretation and was discovered upon subsequent review of the MRS. Molecular studies showed large genomic deletions of a large part of the 3′ end of the complete open reading frame of the SLC6A8 gene. This report emphasizes the importance of MRS in evaluating neurological symptoms, broadens the phenotypic spectrum of CRTR and adds knowledge about the pathogenesis of creatine depletion in the brain and retina.
A single‐residue mutation, G203E, causes 3‐hydroxy‐3‐methylglutaric aciduria by occluding the substrate channel in the 3D structural model of HMG‐CoA lyase
Authors: Mir C. , Lopez‐Viñas E. , Aledo R. , Puisac B. , Rizzo C. , Dionisi‐Vici C. , Deodato F. , Pié J. , Gomez‐Puertas P. , Hegardt F. G. , Casals N. 
Published: April 2006

Summary3‐Hydroxy‐3‐methylglutaric aciduria is a rare autosomal recessive genetic disorder that affects ketogenesis and leucine metabolism. The disease is caused by mutations in the gene coding for 3‐hydroxy‐3‐methylglutaryl‐coenzyme A lyase (HL). To date 26 different mutations have been described. A (βα)8 TIM barrel structure has been proposed for the protein, and almost all missense mutations identified so far localize in the beta sheets that define the inside cavity. We report an Italian patient who bears homozygously a novel HL mutation, c.608G > A (p. G203E) in beta sheet six. A structural model of the mutated protein suggests that glutamic acid 203 impedes catalysis by blocking the entrance to the inner cavity of the enzyme. Loss of functionality has been confirmed in expression studies in E. coli, which demonstrate that the G203E mutation completely abolishes enzyme activity. Beta sheet six and beta sheet two are the two protein regions that accumulate most missense mutations, indicating their importance in enzyme functionality. A model for the mechanism of enzyme function is proposed.
Biochemical compared to molecular diagnosis in acute intermittent porphyria
Authors: Groß U. , Puy H. , Jacob K. , Deybach J. C. , Kremer J. , Doss M. O. 
Published: April 2006

SummaryThe biochemical and the molecular diagnoses of an inherited porphyria require experience. False positive or negative screening tests and the low penetrance of the disease make a correct diagnosis difficult.The biochemical and the molecular procedures for the diagnosis of acute intermittent porphyria were applied to five unrelated patients suffering from acute intermittent porphyria. All patients were shown to be gene carriers of acute intermittent porphyria by both methods. The two different possibilities of the diagnosis corresponded well. In a family definitively identified by molecular diagnosis of one of the patients and his relatives, the patient's two children were asymptomatic. His son was shown to be a gene carrier of the father's deficiency by biochemical as well as molecular analysis, whereas his daughter was not affected by acute intermittent porphyria.
Biochemical and molecular diagnosis of lipoamide dehydrogenase deficiency in a North American Ashkenazi Jewish family
Authors: Sansaricq C. , Pardo S. , Balwani M. , Grace M. , Raymond K. 
Published: April 2006

SummaryA late‐onset presentation of lipoamide dehydrogenase (E3) deficiency is described in a North American Ashkenazi Jewish (AJ) family. Diagnosis was made by urine organic acid and molecular analyses.
Effect of docosahexaenoic acid administration on plasma lipid profile and metabolic parameters of children with methylmalonic acidaemia
Authors: Aldámiz‐Echevarría L. , Sanjurjo P. , Elorz J. , Prieto J. A. , Pérez C. , Andrade F. , Rodríguez‐Soriano J. 
Published: April 2006

SummaryAim. To evaluate the effect of administration of docosahexaenoic acid (DHA) on dyslipidaemia, plasma fatty acid composition and metabolic parameters of children with isolated methylmalonic acidaemia (MMA) (McKusick 25100).Methods. Four children (3 male, 1 female) with MMA (mut(0)), participated in a crossover, randomized study of DHA administration (25 mg/kg per day, divided into three daily doses). The control group comprised 56 healthy children, aged 10± 2.7 years, (51 male, 5 female), who were followed in our clinic owing to possible familial risk of cardiovascular disease.Results. The comparison of plasma fatty acid composition of children with MMA versus control children demonstrated that the patients had significantly higher values for oleic acid (p = 0.004) and linolenic acid (p = 0.008). No differences were observed in the levels of DHA and arachidonic acid. Plasma concentrations of insulin, glycine, ammonia, total cholesterol and cholesterol fractions did not change with DHA administration. No significant changes were observed in urinary excretion of methylmalonic acid. As expected, the percentage of DHA and n−3 fatty acids in plasma increased significantly after therapy (p = 0.005 and 0.014, respectively). The most remarkable result was a decrease of plasma levels of triglycerides after DHA therapy (p = 0.014).Conclusion. As previously found in normal children, dietary supplementation with DHA decreases the triglyceride levels, normalizing the hypertriglyceridaemia of these children without any evidence of short‐term adverse effects.