bluuebunny/crossref_metadata_2025_split huggingface dataset:
Focusing slabs made of negative index materials based on inhomogeneous dielectric rods
Authors: Sergentu V. V. , Ursaki V. V. , Tiginyanu I. M. , Foca E. , Föll H. , Boyd Robert W. 
Published: April 2006

AbstractWe show the advantages of using inhomogeneous dielectric rods to design photonic crystals that behave as materials with negative refractive index. We found that the analysis of light scattering properties of inhomogeneous dielectric rods allows one to estimate the interval of frequencies where a photonic crystal exhibits negative refractive index. A triangular‐lattice photonic crystal – assembled from multilayer dielectric rods designed to approximate a fish‐eye profile – is shown to exhibit negative refractive index and good focusing properties at frequencies where the fish‐eye dielectric rods scatter the light like a medium with negative refractive index. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Process Optimization via Robust Parameter Design when Categorical Noise Factors are Present
Authors: Robinson Timothy J. , Brenneman William A. , Myers William R. 
Published: April 2006

AbstractWhen categorical noise variables are present in the Robust Parameter Design (RPD) context, it is possible to reduce process variance by not only manipulating the levels of the control factors but also by adjusting the proportions associated with the levels of the categorical noise factor(s). When no adjustment factors exist or when the adjustment factors are unable to bring the process mean close to target, a popular approach for determining optimal operating conditions is to find the levels of the control factors that minimize the estimated mean squared error of the response. Although this approach is effective, engineers may have a difficult time translating mean squared error into quality. We propose the use of a parts per million defective objective function. Furthermore, we point out that in many situations the levels of the control factors are not equally desirable due to cost and/or time issues. We have termed these types factors non‐uniform control factors. We propose the use of desirability functions to determine optimal operating conditions when non‐uniform control factors are present and illustrate this methodology with an example from industry. Copyright © 2006 John Wiley & Sons, Ltd.
A QSAR Study of Avian Oral Toxicity using Support Vector Machines and Genetic Algorithms
Authors: Mazzatorta Paolo , Cronin Mark T. D. , Benfenati Emilio 
Published: April 2006

AbstractThis paper presents a study conducted on 116 pesticides to investigate the underlying relationship between structural properties and avian oral toxicity. Data were collected from several sources and screened to ensure quality and consistency. Physico‐chemical and structural descriptors were obtained for the pesticides using the OpenMolGRID system. The resulting dataset was mined using principal component analysis (PCA), genetic algorithms (GA) and other classification algorithms. The final model was obtained using a support vector machine (SVM) combined with genetic algorithms for feature selection. It has good predictive ability (the error rate of the training set=0.021, the error rate of the validation set=0.158). Analysis of the descriptors indicates the prominent role of the interaction of pesticides with macromolecules and/or proteins in the mechanism of action.
Aromaticity‐induced changes in electronic properties of size‐expanded DNA bases: Case of xC
Authors: Fuentes‐Cabrera Miguel , Lipkowski Pawel , Huertas Oscar , Sumpter Bobby G. , Orozco Modesto , Luque F. Javier , Wells Jack C. , Leszczynski Jerzy 
Published: April 2006

AbstractSize‐expanded DNA bases are analogues of natural bases that can be described as a synthesis between benzene and a natural base. Size‐expanded bases have been combined with natural bases to form xDNA and yDNA, a new class of synthetic nucleic acids. We are interested in xDNA and yDNA because they might function as molecular wires. Recently, we also became intrigued by the possibility of altering the electronic conductivity of xDNA and yDNA by means of structural changes in the constituent bases. This possibility appeared after we noticed that the highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap of the base yG can be increased dramatically, ∼0.73 eV, by changing the aromaticity of its benzene ring. Therefore, if one is able to alter the HOMO–LUMO gap of size‐expanded bases, it should be possible to change the electronic conductivity of xDNAs and yDNAs as well. In the present work, we extend our study on aromaticity‐induced changes on the electronic properties of size‐expanded bases by investigating the HOMO–LUMO gap of all possible tautomers of xC. We have found that, as for yG, the HOMO–LUMO gap of xC can be modified by ∼ 0.74 eV, and that this can be accomplished by changing the aromaticity of its benzene ring. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Long‐term outcome and neuroradiological findings of 31 patients with 6‐pyruvoyltetrahydropterin synthase deficiency
Authors: Wang L. , Yu W.‐M. , He C. , Chang M. , Shen M. , Zhou Z. , Zhang Z. , Shen S. , Liu T.‐T. , Hsiao K.‐J. 
Published: April 2006

SummaryTetrahydrobiopterin (BH4) deficiency is an autosomal recessive disorder caused by enzyme defects in the biosynthesis or recycling of BH4. Patients with BH4 deficiency present with severe neurological signs and symptoms and .require a different treatment from classical phenylketonuria. During the last 12 years, 31 cases of BH4 deficiency were identified in our department. They were all classified as 6‐pyruvoyl‐tetrahydropterin synthase (PTPS) deficiency. They were diagnosed at the ages of 2.5–48 months and treated with BH4, L‐dopa and 5‐hydroxytryptophan immediately after diagnosis. The average development quotients (DQ) at diagnosis and after treatment for more than 3 years were 53± 16, and 78± 15, respectively. A significant negative correlation was observed between the level of the DQ and the age at which treatment was commenced (r = −0.751, p = 0.002). Developmental profiles were uneven. Language, adaptability and at later age mathematics were particularly weak areas. Only two patients achieved a good performance in mathematics. Eleven patients who were treated with drugs from ages of 2.9–48 months had neuroradiological scanning. Computed tomography disclosed calcification in lentiform nuclei in one patient and magnetic resonance imaging disclosed delayed myelination and abnormal high intensity signal in cerebral white matter in all of them. Even though most of abnormalities were reversible, small patchy or spotted areas were still present on these regions after treatment for 10–46 months. In summary, our study supports the substantial efficacy of the current therapeutic approach in PTPS deficiency of normalizing amine neurotransmitters with three drugs as early as possible. For the first time, calcifications could be detected in patients with PTPS deficiency. Abnormalities in white matter on magnetic resonance imaging were not related to clinical manifestations and most were reversible.
Severe normotensive metabolic alkalosis in a 2‐month‐old boy with hyperekplexia
Authors: Schlapbach L. J. , Sozzo A. , Ramelli G. , Bianchetti M. G. 
Published: April 2006

SummaryA 2‐month‐old infant with hereditary hyperekplexia, umbilical and bilateral inguinal hernias and history of poor feeding was noted to have severe normotensive metabolic alkalosis: sodium 132 mmol/L, potassium 3.4 mmol/L, chloride 77 mmol/L, pH 7.55, carbon dioxide tension 56.3 mmHg and bicarbonate 48.0 mmol/L. After parenteral rehydration and treatment with clonazepam, laboratory parameters normalized.
The spectrum of phenylalanine variations under tetrahydrobiopterin load in subjects affected by phenylalanine hydroxylase deficiency
Authors: Leuzzi V. , Carducci C. , Carducci C. , Chiarotti F. , Artiola C. , Giovanniello T. , Antonozzi I. 
Published: April 2006

SummaryA fall in blood phenylalanine (Phe) after tetrahydrobiopterin (BH4) administration is a common trait in phenylalanine hydroxylase (PAH, EC 1.14.16.1) deficiency (McKusick 261600). To explore the extent and biological correlates of this phenomenon we studied: (a) the spectrum of BH4 response in patients with PAH deficiency; (b) the variability of BH4 response according to the severity of the biochemical phenotype; and (c) the variability of the response to BH4 in subjects with the same genotype. Fifty PAH‐deficient subjects (age 1 month–35 years) were enrolled for the study (5 with mild hyperphenylalaninaemia (MHPHE), 15 with mild phenylketonuria (MPKU) and 30 with classic phenylketonuria (CPKU) and underwent an identical schedule of blood samplings 24 h before and after oral BH4 challenge (6(R)‐BH4, 20 mg/kg per day), leaving Phe intake unchanged. The effect of BH4 on blood Phe concentration was evaluated according to the percent decrease of Phe during the 24 h following the challenge (criterion a), and as variation exceeding the individual variability of blood Phe (criterion b). The number of BH4‐responders according to criterion b was 31 (including all the 14 detected by criterion a): 17 out of 30 CPKU (57%), 9 out of 15 MPKU (60%), and all the MHPHE subjects (χ2 = 3.45, df = 2, p = 0.178). The effect of BH4 showed a large interindividual variability unrelated to diagnostic classification, basal value of blood Phe, maximum percentage of Phe reduction, Phe intake, and genotype. Some inconsistencies were found in patients with identical genotype. The first responsive case homozygous for the severe R408W mutation was found. Two new mutations, Y387X and G352C, were identified (the former was BH4‐responsive), and the responsiveness of three already reported mutations (R261Q, D338Y, T92I) was substantiated.
Homocysteine metabolism, hyperhomocysteinaemia and vascular disease: An overview
Authors: Castro R. , Rivera I. , Blom H. J. , Jakobs C. , de Almeida I. Tavares 
Published: April 2006

SummaryHyperhomocysteinaemia has been regarded as a new modifiable risk factor for atherosclerosis and vascular disease. Homocysteine is a branch‐point intermediate of methionine metabolism, which can be further metabolised via two alternative pathways: degraded irreversibly through the transsulphuration pathway or remethylated to methionine by the remethylation pathway. Both pathways are B‐vitamin‐dependent. Plasma homocysteine concentrations are determined by nongenetic and genetic factors. The metabolism of homocysteine, the role of B vitamins and the contribution of nongenetic and genetic determinants of homocysteine concentrations are reviewed. The mechanisms whereby homocysteine causes endothelial damage and vascular disease are not fully understood. Recently, a link has been postulated between homocysteine, or its intermediates, and an alterated DNA methylation pattern. The involvement of epigenetic mechanisms in the context of homocysteine and atherosclerosis, due to inhibition of transmethylation reactions, is briefly overviewed.
HHH syndrome (hyperornithinaemia, hyperammonaemia, homocitrullinuria), with fulminant hepatitis‐like presentation
Authors: Fecarotta S. , Parenti G. , Vajro P. , Zuppaldi A. , Casa R. Della , Carbone M. T. , Correra A. , Torre G. , Riva S. , Dionisi‐Vici C. , Santorelli F. M. , Andria G. 
Published: April 2006

SummaryWe report a 3‐year‐old Italian patient with the hyperornithinaemia, hyperammonaemia, homocitrullinuria (HHH) syndrome who presented with neurological deterioration after an intercurrent infection. Hyperammonaemia, coagulopathy and moderate hypertransaminasaemia were detected on hospital admission. Severe hepatocellular necrosis with hypertransaminasaemia (aspartate aminotransferase 20 000 UI/L, alanine aminotransferase 18 400 UI/L) and coagulopathy (PT < 5%) rapidly developed within few days, prompting evaluation for liver transplantation. A protein‐restricted diet and arginine supplementation were immediately started, with a rapid improvement of the patient's neurological conditions and normalization of liver function tests and blood ammonia. The diagnosis of HHH syndrome was based on the presence of the typical metabolic abnormalities. Molecular analysis of the SLC25A15 gene showed that the patient was heterozygous for two novel mutations (G113C and M273K). The diagnosis of HHH syndrome should be considered in patients with fulminant hepatitis‐like presentations. Early identification and treatment of these patients can be life‐saving and can avoid liver transplantation.
Successful liver transplantation for argininosuccinate lyase deficiency (ASLD)
Authors: Robberecht E. , Maesen S. , Jonckheere A. , Van Biervliet S. , Carton D. 
Published: April 2006

SummaryLiver transplantation was performed in a girl with early‐onset ASLD, leading to unrestricted protein intake and no further neurological deterioration.
A patient with common glycogen storage disease type Ib mutations without neutropenia or neutrophil dysfunction
Authors: Martens D. H. J. , Kuijpers T. W. , Maianski N. A. , Rake J. P. , Smit G. P. A. , Visser G. 
Published: April 2006

SummaryWe describe a 16‐year old boy with glycogen storage disease type Ib, homozygous for the common 1211–1212delCT mutation, who never experienced neutropenia, and did not suffer from frequent infections or inflammatory bowel disease. In addition, neutrophil function tests showed no abnormalities.
Measurement of ATP production in mitochondrial disorders
Authors: Shepherd R. K. , Checcarelli N. , Naini A. , De Vivo D. C. , DiMauro S. , Sue C. M. 
Published: April 2006

SummaryMitochondrial diseases are a heterogeneous group of disorders caused by mutations in both nuclear DNA (nDNA) and mitochondrial DNA (mtDNA). Mitochondrial disease leads to impaired respiratory chain function and reduced ATP production. The aim of this study was to compare disturbances in mitochondrial function by measuring ATP synthesis in fibroblasts derived from patients with nDNA and mtDNA defects. Skin fibroblasts derived from 22 patients with either nDNA‐related disorders (n = 8) or mtDNA‐related disorders (n = 14) were analysed. ATP synthesis was markedly decreased in fibroblasts derived from patients with nDNA‐related disorders but only variably so in patients with mtDNA mutations. In fibroblasts with the MELAS 3243A > G mutation, ATP synthesis correlated with mutant load. We believe that the observed differences in ATP production between cell lines derived from patients with nDNA‐related disorders and mtDNA‐related disorders may help in the assessment of patients with undiagnosed mitochondrial disease. The clinical comparisons observed in patients with nDNA‐ and mtDNA‐related disorders may be explained by differences in the disturbance of ATP synthesis measured in the two conditions.
Psychological complications of patients with Gaucher disease
Authors: Packman W. , Crosbie T. Wilson , Riesner A. , Fairley C. , Packman S. 
Published: April 2006

SummaryThe Minnesota Multiphasic Personality Inventory (MMPI‐2) is commonly used in chronic illness and chronic pain populations to assess psychological functioning. We report the results of the first study employing the MMPI‐2 to assess psychological aspects of patients with Gaucher disease, type I (GD) is an inborn error of metabolism with unique features as a chronic illness: the disorder often presents with mild symptoms, and is frequently diagnosed in later childhood or adulthood; the treatment is highly efficacious, but, that same treatment is intrusive and expensive and requires that patients restructure their work and personal schedules. In this study, 28 patients with GD completed the MMPI‐2 and a background questionnaire. GD patients scored significantly higher than the MMPI‐2 normative sample on MMPI‐2 scales of Validity (K), Hypochondriasis (Hs), Depression (D), Hysteria (Hy), Psychasthenia (Pt) and Schizophrenia (Sc). Individuals with elevated scores on the Hs, D and Hy scales tend to have somatic concerns and depressed mood. Under stress, they are likely to report physical symptoms. Elevated Pt and Sc scales suggest psychological turmoil and, possibly feelings of isolation. An elevated K scale indicates a tendency for individuals to deny psychopathology. The length of time the patient with GD had been on enzyme replacement therapy was not significantly related to any of the 13 MMPI‐2 scales. Cohorts of patients with chronic heart disease (CRHD) and cohorts of patients with chronic pain were utilized as comparative populations in this investigation. The elevated scores of the GD patients on MMPI‐2 scales Hs, D and Hy were similar to those of the CRHD population. The chronic pain patients also showed elevations on MMPI‐2 scales Hs, D and Hy, which were elevated in the GD patients; the elevations in the chronic pain patients were higher than those shown by the GD patients. We conclude that patients with GD exhibit moderate to severe psychological complications, similar to patients with other long‐term chronic illnesses.
An unusual clinical and biochemical presentation of ornithine transcarbamylase deficiency in a male patient
Authors: Burlina A. B. , Peduto A. , Palma A. Di , Bellizzi A. , Sperlì D. , Morrone A. , Burlina A. P. 
Published: April 2006

SummaryWe report a male patient with a history of recurrent idiopathic vomiting, normal plasma ammonia and glutamine concentrations in acute phase, who died at 3 years of age. Ornithine transcarbamylase deficiency was diagnosed after detecting elevated urinary orotate concentrations in a sample collected just before death, and the diagnosis was confirmed by DNA analysis.
Two cases of citrullinaemia presenting with stroke
Authors: Choi J. H. , Kim H. , Yoo H. W. 
Published: April 2006

SummaryUrea cycle disorders are known to be unusual causes of stroke. We report two infant cases of citrullinaemia that both initially presented with a stroke and suggest that urea cycle disorders should be included in the differential diagnosis of unexplained stroke during infancy and childhood.
Fatty acid oxidation in the human fetus: Implications for fetal and adult disease
Authors: Oey Nadia A. , Ruiter Jos P. N. , Attié‐Bitach Tania , IJlst Lodewijk , Wanders Ronald J. A. , Wijburg Frits A. 
Published: April 2006

SummaryStudies in the last few years have shown a remarkably high activity of fatty acid oxidation (FAO) enzymes in human placenta. We have recently shown mRNA expression as well as enzymatic activity of long‐chain FAO enzymes in the human embryo and fetus. In this study we show activity of the FAO enzymes carnitine palmitoyltranferase 1, medium‐chain acyl‐CoA dehydrogenase and short‐chain hydroxyacyl‐CoA dehydrogenase in embryonic and fetal tissues. In addition, we show the presence of different acylcarnitines in fetal liver and kidney, which substantiates the notion that the mitochondrial FAO enzymes are not only present in human fetal tissues but also metabolically active. In a glucose‐rich environment FAO might be necessary for additional ATP production from fatty acids, but also for the breakdown of fatty acids that are products of the turnover of membranes in the growing fetus. The importance of FAO in the human embryo and fetus is further stressed by the fact that a higher frequency of prematurity, intrauterine growth retardation, fetal morbidity and intrauterine death is noted in long‐chain FAO defects. Furthermore, in animal studies, gestational loss during early embryonic development has been observed as a consequence of disturbed FAO. Finally, there are indications that regulation of activity of FAO during fetal development might not only be important for fetal life but may also have implications for health and disease in adulthood.
The longest‐surviving patient with classical maple syrup urine disease
Authors: le Roux Carel , Murphy Elaine , Lilburn Maggie , Lee Philip J. 
Published: April 2006

SummaryThe clinical problems, dietary management and biochemical monitoring over a 40‐year period of the longest‐surviving patient with maple syrup urine disease are described. Her case illustrates that a good outcome can be obtained with early diagnosis and institution of a diet restricted in branched‐chain amino acids. Changes in dietary supplementation have benefited her in terms of nutrition and quality of life. Consistently high blood concentrations of branched‐chain amino acids have not been associated with neuropsychometric decline.
Asymmetric dimethylarginine in homocystinuria due to cystathionine β‐synthase deficiency: Relevance of renal function
Authors: Wilcken David E. L. , Wang Jun , Sim Ah Siew , Green Kathryn , Wilcken Bridget 
Published: April 2006

SummaryObjective Vascular disease is associated with increased plasma asymmetric dimethylarginine (ADMA) and homocysteine, and both are increased in renal failure. In cystathionine β‐synthase deficiency (CBS) there is severe hyperhomocysteinaemia, precocious vascular disease, and endothelial dysfunction. We investigated whether ADMA levels are elevated in CBS patients with and without renal impairment, and whether lowering plasma homocysteine also lowers ADMA.Methods We measured plasma homocysteine, arginine, asymmetric and symmetric dimethylarginines, nitrate + nitrite, creatinine and cystatin C in 23 CBS‐deficient patients and 24 age‐matched controls.Results In the patients, nitrate + nitrite and the ratio L‐arginine/ADMA were markedly reduced (21.6 ± 6.1 vs 57.7 ± 7.5 μmol/L and 132.9 ± 24.7 vs 181.9 ± 56.1, respectively, p < 0.001 for both), reflecting endothelial dysfunction. Plasma ADMA for the group was moderately increased (0.55 ± 0.08 vs 0.49 ± 0.07 μmol/L, p = 0.018), but this was due to significantly higher levels than controls in only those 7 of the 23 patients who had elevated cystatin C levels (0.59 ± 0.08 vs 0.49 ± 0.07 mg/L, p = 0.007). Posttreatment total homocysteine in patients varied widely (15–285, median 92 μmol/L), but was not correlated with ADMA or other measured variables. In three newly‐diagnosed patients, marked reduction of total homocysteine during treatment produced minimal changes in ADMA.Conclusions ADMA levels were significantly increased only in the CBS‐deficient patients with elevated cystatin C levels, and not in those with normal renal function. The reported relationship between hyperhomocysteinaemia and ADMA may not be direct, but could be secondary to reduced renal function.
X‐Linked creatine transporter deficiency in two patients with severe mental retardation and autism
Authors: Póo‐Argüelles P. , Arias A. , Vilaseca M. A. , Ribes A. , Artuch R. , Sans‐Fito A. , Moreno A. , Jakobs C. , Salomons G. 
Published: April 2006

SummaryWe describe the first two unrelated Spanish patients with creatine transporter deficiency initially identified by brain proton magnetic resonance spectroscopy (MRS). The clinical phenotype was characterized by severe mental retardation, epilepsy, autism, severe speech delay and absence of brain creatine by MRS. Urine creatine/creatinine ratio was increased and creatine uptake in fibroblasts was impaired in both patients. On DNA sequence analysis of the SLC6A8/creatine transporter gene, one hemizygous mutation was found in each patient: one mutation was novel and consisted of a deletion of two nucleotides c.878–879delTC in exon 5, resulting in a frameshift (p.Lys293fsX3), and in the other patient a known deletion of three nucleotides 1222–1224delTTC in exon 8 resulting in p.Phe408del. Creatine treatment for one year failed to improve the neurological symptoms and was associated with a striking increase in body weight in both patients (13 and 16 kg, respectively).