bluuebunny/crossref_metadata_2025_split huggingface dataset:
Release of salbutamol sulphate and ketoprofen enantiomers from matrices containing HPMC and cellulose derivatives
Authors: Solinís M. Angeles , de la Cruz Yaimy , Calvo Begoña , Hernández Rosa M. , Gascón Alicia R. , Goñi Isabel , Gurruchaga M. Dolores , Pedraz José Luis 
Published: October 2002

AbstractWe studied the release of salbutamol and ketoprofen enantiomers from HPMC K100M matrices containing two types of cellulose derivatives: cellulose tris (3,5‐dimethylphenylcarbamate) and cellulose tris (2,3‐dichlorophenylcarbamate), chiral excipients used as stationary phases for liquid chromatography. These matrices provided an extended release of both drugs. Ketoprofen release from formulations elaborated with cellulose tris (2,3‐dichlorophenylcarbamate) was by anomalous transport, because the value of n (release exponent of the diffusion equation) ranged between 0.60–0.68, whereas for all other formulations the value of exponent n ranged from 0.50–0.54. The drug thus diffuses through the matrix and is released following a quasi‐Fickian diffusion mechanism (stereoselective process). The matrices preferentially retained R‐salbutamol and S‐ketoprofen and cellulose tris (3,5‐dimethylphenylcarbamate) showed more capacity of chiral discrimination for both drugs than cellulose tris (2,3‐dichlorophenylcarbamate). Moreover, we observed that stereoselectivity is dependent on the amount of chiral excipient in the formulation. Diffusion tests confirmed the chiral interaction between drugs and cellulose derivatives observed in the dissolution assays except for matrices elaborated with ketoprofen and cellulose tris (2,3‐dichlorophenylcarbamate), where the low stereoselectivity observed with the matrices is due to the presence of HPMC K100M. We conclude that the inclusion of these cellulose derivatives in HPMC matrices does not result in a relevant stereoselectivity with respect to the two drugs studied. Chirality 14:806–813, 2002. © 2002 Wiley‐Liss, Inc.
Solution structure of diastereomeric thymidine 3′‐O(N,N‐diisopropyl‐O‐β‐cyanoethyl‐phosphoramidothioate)s by NMR spectroscopy
Authors: Gács‐Baitz Eszter , Kajtár‐Peredy Mária 
Published: October 2002

AbstractThe conformational properties of a diastereomeric nucleoside‐phosphorothioate pair is reported as reflected by different NMR parameters. Configurational assessment is based partly on the different NOE (nuclear overhauser enhancement) effects of the individual isomers and on the trends observed in other NMR parameters. Vicinal carbon‐phosphorus couplings reflect the predominance of the ϵ‐ conformation for the Sp isomer and the ϵt conformation for the Rp isomer. The effects of solvent and temperature on these vicinal couplings are described and the results are interpreted in terms of conformational shift towards the preferred ϵt conformation. Chirality 14:814–818, 2002. © 2002 Wiley‐Liss, Inc.
Optical rotation: Recent advances in determining the absolute configuration
Authors: Polavarapu Prasad L. 
Published: October 2002

AbstractThe field of optical rotations is currently undergoing a renaissance, which is a direct result of the advances in quantum mechanics and the availability of faster desktop computers. In the last few years, the field of optical rotations has taken an important role for determining the three‐dimensional molecular structure (absolute configuration and conformations) with confidence. The purpose of this review is to present the latest advances in this area so that practicing chemists can utilize them in their respective areas of research and development. Chirality 14:768–781, 2002. © 2002 Wiley‐Liss, Inc.
Polyproline II structure in proteins: Identification by chiroptical spectroscopies, stability, and functions
Authors: Bochicchio Brigida , Tamburro Antonio Mario 
Published: October 2002

AbstractIn the last years polyproline II (PPII) structure has been demonstrated to be essential to biological activities such as signal transduction, transcription, cell motility, and immune response. The polyproline left‐handed helical structure was nearly unknown until now and often confused with unordered, disordered, irregular, unstructured, extended, or random coil conformations because it is neither α‐helical nor β‐turn nor β‐sheet, i.e., a classical structure. In spite of the regularity of the PPII structure and, more precisely, its well‐defined dihedral angle values, a typical feature of PPII structure is the absence of any intramolecular hydrogen bonds that renders the PPII structure indistinguishable from an irregular backbone structure by 1H‐NMR spectroscopy. The only way to unambiguously reveal PPII structure in solution is to use spectroscopies based on optical activity, such as circular dichroism (CD), vibrational circular dichroism (VCD), and Raman optical activity (ROA). Herein we focus on the identification of PPII structure by CD, widely considered to be the most reliable methodology. Then we report on VCD and ROA spectroscopies as tools in the identification of PPII structure. A third section is dedicated to the analysis of the stabilization of PPII conformation in aqueous solution. Finally, the significance of PPII in self‐assembly processes, in elasticity of elastomeric proteins, and in proteins‐(peptides) proteins molecular recognition processes are considered. Chirality 14:782–792, 2002. © 2002 Wiley‐Liss, Inc.
Polar signal averaging
Authors: Thomas G.W. , Bachman H.N. , Sigmund E.E. , Mitrović V.F. , Calder E.S. , Halperin W.P. 
Published: October 2002

AbstractSignals suffering from phase noise, such as spin echoes from NMR experiments in a fluctuating magnetic field, can be underestimated by traditional signal averaging. Averaging in the polar rather than in the Cartesian domain can solve this problem. However, because of background noise, there is an inherent drawback in the polar averaging technique: polar averaging under conditions of a low initial signal to noise will cause these same signals to be overestimated. We studied this problem with both numerical simulations and experiments. The quantitative results allow not only an assessment of the applicability of polar averaging for a given experiment but also possible corrections of the overestimate. © 2002 Wiley Periodicals, Inc. Concepts Magn Reson 14: 359–364, 2002
Data acquisition and analysis of broad chemical‐shift powder patterns from solids with spin–echo techniques
Authors: Van Bramer S.E. , Glatfelter A. , Bai S. , Dybowski C. , Neue G. 
Published: October 2002

AbstractThe data acquisition and processing of the wide‐line chemical‐shift NMR spectra of solids present unique challenges. Developing procedures to minimize and address inherent distortions is critical for the proper determination of NMR chemical‐shift parameters from these wide‐line spectra. The analysis of such data provides an understanding of many assumptions that are made about solids and liquids in spectroscopy. We discuss techniques for the analysis of spin–echo spectra broadened by chemical‐shift dispersion. © 2002 Wiley Periodicals, Inc. Concepts Magn Reson 14: 365–387, 2002
Signal de‐noising in magnetic resonance spectroscopy using wavelet transforms
Authors: Cancino‐De‐Greiff Hector F. , Ramos‐Garcia Rubersy , Lorenzo‐Ginori Juan V. 
Published: October 2002

AbstractComputer signal processing is used for quantitative data analysis (QDA) in magnetic resonance spectroscopy (MRS). The main difficulty in QDA is that MRS signals appear to be contaminated with random noise. Noise reduction can be achieved by coherent averaging, but it is not always possible to average many MRS waveforms. Wavelet shrinkage de‐noising (WSD) is a technique that can be employed in this case. The potentialities of WSD in MRS, alone and combined with the Cadzow algorithm, are analyzed through computer simulations. The results can facilitate an appropriate application of WSD, as well as a deeper understanding of this technique. © 2002 Wiley Periodicals, Inc. Concepts Magn Reson 14: 388–401, 2002
Maximum likelihood constrained deconvolution. I: Algorithm and qualitative and quantitative enhancement in synthetic two‐dimensional NMR spectra
Authors: Jeong Gwang‐Woo , Kang Heoung‐Keun 
Published: October 2002

AbstractThe maximum likelihood method is a constrained iterative spectral deconvolution technique in which a spectral fitting model is determined by minimizing the variance of fit in the time domain in a nonlinear iterative manner. Application of this method to synthetic 2‐dimensional (2‐D) NMR spectra, which have heavily overlapped multiplets associated with low signal to noise ratios, yields contrast‐enhanced spectra with simultaneous noise suppression and resolution improvement. This protocol greatly facilitates peak recognition and often partitions overlapping multiplets into individual components, leading to a more accurate interpretation of resonance frequencies, coupling constants, and multiplets than does the conventional apodization or Fourier transform method. These advantages are useful for constructing reliable 3‐D molecular structures for complex molecular systems. © 2002 Wiley Periodicals, Inc. Concepts Magn Reson 14: 402–415, 2002
Color difference predicted by color component differences
Authors: Indow Tarow 
Published: October 2002

AbstractA relationship between assessed color differences and assessed components of colors is presented. The perceptual difference between colors j and k is converted to a lightness difference of two Munsell grays, VA and VB, and djk = |VA − VB|. Scaled values of principal hue components of a color ξα(H|V/C), α = R, Y, G, and B, are read from charts based on assessments of observers. Previous charts (Color Research and Application, 1999, 24, 266–279) are enlarged and extended. A linear combination of ΔV = |Vj − Vk| and Δξα = |ξα(Hj|Vj/Cj) − ξα(Hk|Vk /Ck)|, d̃jk, is the best to predict djk. The root‐mean‐squares of (djk − d̃jk) is 0.34 V, about one third of the lightness difference from V to V + 1 on the Munsell Value Scale.
Influence of chemical and mineralogical composition on color for commercial talcs
Authors: Soriano M. , Sánchez‐Marañón M. , Melgosa M. , Gámiz E. , Delgado R. 
Published: October 2002

AbstractCommercial talcs are pulverized mineral products with a variable chemical and mineralogic composition, widely used in industry. Although generally white, they have color variations. The aim of this study was to establish relationships between color parameters and the chemical and mineralogic composition of commercial talc samples, in order to investigate the causes of color. Chlorite, dolomite, magnesite, and calcite were the most abundant accessory minerals. Fe, Mn, Ti, and Ni were the most abundant chromophore chemical elements. Factor statistical analysis (89.8% of total variance explained) revealed that the influence of each mineral species on the different color parameters a*, b*, and L* is well defined (the highest loading factors). Chlorite associated with Fe, Mn, Ti, Zr, Cu, Zn, and V, and calcite associated with Zn, Cu, Sr (and, to a lesser degree, Fe, Mn, Ni, and Co) affect the color parameters a* and b* by inducing chromatic variations (greening and yellowing). Dolomite and magnesite associated with Fe, Sr, Ni, Co, V (and, to a lesser extent, Mn and Cu) affect L* by inducing darkening.
Environmental colour design for the third millennium: An evolutionary standpoint
Authors: Tosca Theano Fannie 
Published: October 2002

AbstractThis is a study based on observation, research, literature, and design of the effect of environmentally applied colour on human evolution. Given the structuring abilities of colour, here, it is first examined here how it can help to make the emerging man–environment system a living evolvable entity. Then follows a description of a related design approach for improvement by lighting design as practiced recently by world‐known artists and researched by the Colour Semiotics Study Group under the author's direction. It is argued that, by its increasing complexity, flexibility, and sensorimotor stimulation, environmental colour may raise not only the visual but also the broader perceptual capacities of man with regard to selected qualities. The extension of the human consciousness through machine‐aided imagery and scientific knowledge, finally, calls for a new kind of colour–light organization of the environment, based on the interplay of sensory stimulation and intellectual processes, professional design, and user interaction, in tune with our new understanding of the cosmologic law as constant regeneration. The very structure of this article is intended to exemplify the concept of the portended intertwining of cognitive and intuitive processes in the act of creation central to the study.
Transition metals and polyol pathway in the development of diabetic neuropathy in rats
Authors: Nakamura Jiro , Hamada Yoji , Chaya Sadao , Nakashima Eitaro , Naruse Keiko , Kato Koichi , Yasuda Yutaka , Kamiya Hideki , Sakakibara Fumihiko , Koh Naoki , Hotta Nigishi 
Published: October 2002

AbstractBackgroundThe transition metal–catalyzed reaction is a major source of oxygen free radicals, which play an important role in vascular dysfunction leading to ischemia in diabetic tissues. The inhibition of polyol pathway hyperactivity has been reported to ameliorate neurovascular abnormalities in diabetic rats and has been proposed to improve the oxygen free radical scavenging capacity. The present study was conducted to compare the effect of a transition metal chelating agent, trientine (TRI), on diabetic neuropathy with that of an aldose reductase inhibitor, NZ‐314 (NZ).MethodsDiabetic rats were divided into three groups: (1) untreated, (2) TRI‐treated, and (3) NZ‐treated. TRI (20 mg/kg) or NZ (100 mg/kg) was administered by gavage or chow containing NZ, respectively, for 8 weeks. Motor nerve conduction velocity (MNCV), coefficient of variation of the R − R interval on electrocardiogram (CVr‐r), sciatic nerve blood flow (SNBF), platelet aggregation activities, and serum concentrations of malondialdehyde were measured.ResultsUntreated diabetic rats showed delayed MNCV, decreased CVR−R, and reduced SNBF compared to normal rats. TRI or NZ completely prevented these deficits. Platelet hyperaggregation activities in diabetic rats were prevented by NZ, but not by TRI. Increased concentrations of malondialdehyde in diabetic rats were partially but significantly ameliorated by either TRI or NZ.ConclusionsThese observations suggest that increased free radical formation through the transition metal–catalyzed reaction plays an important role in the development of diabetic neuropathy and that the preventive effect of an aldose reductase inhibitor on diabetic neuropathy may also be mediated by decreasing oxygen free radicals. Copyright © 2002 John Wiley & Sons, Ltd.
An adipocentric view of signaling and intracellular trafficking
Authors: Mora Silvia , Pessin Jeffrey E. 
Published: October 2002

AbstractAdipocytes have traditionally been considered to be the primary site for whole body energy storage mainly in the form of triglycerides and fatty acids. This occurs through the ability of insulin to markedly stimulate both glucose uptake and lipogenesis. Conventional wisdom held that defects in fuel partitioning into adipocytes either because of increased adipose tissue mass and/or increased lipolysis and circulating free fatty acids resulted in dyslipidemia, obesity, insulin resistance and perhaps diabetes. However, it has become increasingly apparent that loss of adipose tissue (lipodystrophies) in both animal models and humans also leads to metabolic disorders that result in severe states of insulin resistance and potential diabetes. These apparently opposite functions can be resolved by the establishment of adipocytes not only as a fuel storage depot but also as a critical endocrine organ that secretes a variety of signaling molecules into the circulation. Although the molecular function of these adipocyte‐derived signals are poorly understood, they play a central role in the maintenance of energy homeostasis by regulating insulin secretion, insulin action, glucose and lipid metabolism, energy balance, host defense and reproduction. The diversity of these secretory factors include enzymes (lipoprotein lipase (LPL) and adipsin), growth factors [vascular endothelial growth factor (VEGF)], cytokines (tumor necrosis factor‐α, interleukin 6) and several other hormones involved in fatty acid and glucose metabolism (leptin, Acrp30, resistin and acylation stimulation protein). Despite the large number of molecules secreted by adipocytes, our understanding of the pathways and mechanisms controlling intracellular trafficking and exocytosis in adipocytes is poorly understood. In this article, we will review the current knowledge of the trafficking and secretion processes that take place in adipocytes, focusing our attention on two of the best characterized adipokine molecules (leptin and adiponectin) and on one of the most intensively studied regulated membrane proteins, the GLUT4 glucose transporter. Copyright © 2002 John Wiley & Sons, Ltd.
Current knowledge of Japanese type 1 diabetic syndrome
Authors: Abiru Norio , Kawasaki Eiji , Eguch Katsumi 
Published: October 2002

AbstractThe Japanese have one of the lowest incidence of childhood type 1 diabetes in the world, but the incidence of this disease is clearly increasing within the Japanese population, as reported in several European countries. Latent autoimmune diabetes mellitus in adult (LADA) patients are also likely to have a lower incidence compared to Caucasians. Among the non‐autoimmune (type 1B) diabetes in Japanese adults, there exists a novel subtype of type 1 diabetes characterized by extremely rapid onset and pancreatic exocrine inflammation. HLA and non‐HLA gene associations to type 1 diabetes may vary depending on ethnic origin. Highly susceptible HLA haplotypes of type 1 diabetes observed in Caucasian patients are not found in Japanese patients, while protective HLA haplotypes are similar. Association studies of non‐HLA genes have identified several candidate genes that influence the heterogeneity of disease phenotypes as well as disease susceptibility to type 1 diabetes. The INS‐VNTR gene or polymorphisms of MICA gene are associated with susceptibility, whereas a certain allele of MICA gene and IL‐10 gene polymorphism are associated with clinical heterogeneity of the disease. An expression of multiple autoantibodies to a biochemically determined autoantigen confers a high risk for progression to type 1 diabetes. The combined evaluation of multiple autoantibodies is more sensitive than is ICA testing for the diagnosis of type 1 diabetes. A high titer of GAD autoantibody has the predictive value of future insulin deficiency in patients with LADA. For accurate predictive strategies of future insulin deficiency, combinational multiple autoantibodies analysis or genetic determination should be considered for effective immune intervention. Copyright © 2002 John Wiley & Sons, Ltd.
Children with dyslexia are slow to articulate a single speech gesture
Authors: Fawcett Angela J. , Nicolson Roderick I. 
Published: October 2002

AbstractIn addition to their well‐established problems in phonological processing, children with dyslexia show reduced speed of articulation. Two groups of children with dyslexia, mean ages 13 and 16 years, participated together with two groups of normally achieving children matched for age and IQ, with 33 participants in total. Participants were asked to articulate repeatedly, as fast as they could, either a single articulatory gesture /p/ /t/ or /k/ or the sequence ‘putuku’. The waveforms generated were analysed in two ways; the time per gesture excluding inter‐articulatory pauses (articulatory duration); and the mean time including the pauses (gesture duration). No age effects were found, but dyslexic groups were significantly slower on all tests. Deficits were greater in relative magnitude for gesture duration than articulatory duration. The results suggest that children with dyslexia have significant problems in articulation, not only in gesture planning, but also in the speeded production of single articulatory gestures. Copyright © 2002 John Wiley & Sons, Ltd.
Comments on ‘the dyslexia ecosystem’: a reply to Nicolson
Authors: Richards Ian L. , Witton Caroline , Moores Elisabeth , Reddy Peter A. , Rippon Gina , Talcott Joel B. 
Published: October 2002

AbstractThe central issue facing the dyslexia community, and the underlying theme of Nicolson's ‘The Dyslexia Ecosystem’ (Nicolson, 2002, Dyslexia, 8, 55–66), is how we can best translate what we know about this particular developmental disorder into practice to give each child the greatest opportunity of acquiring the enabling skill of literacy. To achieve this, and notwithstanding Nicolson's caveat on this point, we have to consider how we can best move from our sphere of expertise to a greater sphere of influence, both as individuals and as a community of research practitioners. In our response, we first consider aspects of Nicolson's general analysis of ‘The Dyslexia Ecosystem’ and then examine some of the specific objectives that have been proposed. Copyright © 2002 John Wiley & Sons, Ltd.
The association of abnormal cerebellar function in children with developmental coordination disorder and reading difficulties
Authors: O'Hare Anne , Khalid Shabana 
Published: October 2002

AbstractChildren with developmental coordination disorder/dyspraxia (DCD) are at high risk of reading and writing delay. The difficulties with motor skills are heterogeneous and many children have features of poor cerebellar function, reflected in problems with posture, balance and fast accurate control of movement. This study confirmed a high level of parental reporting of reading and writing delay in a clinical group of 23 children with DCD, defined on the basis of both clinical examination and standardized testing of motor function. Direct measurement of reading delay, identified still further children in the group. Those children with reading delay had associated findings typical of phonological awareness difficulties. The children also underwent a standardized test of neurological function and although they all had difficulties with cerebellar function, no distinctive pattern emerged for those whose presentation was complicated by delayed reading and writing. Both the children with DCD and 136 typically developing children, completed the pilot parental questionnaire on gross motor skills. The three skills of catching a ball, jumping on a moving playground roundabout and handwriting, distinguished the children with DCD. This study therefore confirms that children with DCD should be assessed for difficulties in phonological awareness. Additionally, children aged between 7 and 12 years are on the whole, highly competent in a range of gross motor skills and further study might determine whether a simple parental questionnaire might detect children who would benefit from further assessment. The study also suggests that all the children with DCD have cerebellar dysfunction and further work with a larger group might determine particular patterns associated with reading delay. Copyright © 2002 John Wiley & Sons, Ltd.
Electromagnetic analysis of inductrack magnetic levitation
Authors: Murai Toshiaki , Hasegawa Hitoshi 
Published: October 2002

AbstractA new type of magnetic levitation system called the Inductrack has been proposed by R. F. Post. This system is composed of a special arrangement of permanent magnets on board which is called the Halbach array, and a close‐packed array of shorted coils in the longitudinal direction on the ground. This composition can obtain a large magnetic force, a very low take‐off speed, and a high lift‐to‐drag ratio. This paper describes numerical simulations of the Inductrack magnetic levitation by the Fourier series analysis which is utilized in the analysis of superconducting magnetic levitation. By using numerical examples considering a full‐scale car model, we reveal the features of the Inductrack system in comparison with the superconducting magnetic levitation. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 67–74, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10061