bluuebunny/crossref_metadata_2025 huggingface dataset:
Inelastic Background and Peak Area Determination in X-Ray Photoelectron Spectroscopy (ESCA)
Authors: Proctor Andrew , Hercules David M.
Published: July 2005

Analysis of the Au 4f ESCA spectra of thin gold films deposited over a graphite base shows that as the separation from the main photoelectron peak, ΔE, increases the background decreases. Conversely, the effect of a contaminant overlayer on solid gold gives rise to a background which increases as ΔE increases. There is, therefore, a considerable variety of background profiles which can be encountered in real samples, which depends markedly on the element, its concentration, and its distribution in the sample. Over the region of the photoelectron line signal itself, the simple integral description which assumes that the background is proportional to the number of electrons of higher kinetic energy is reasonably valid and is suggested for peak area measurement when a nonlinear profile is needed.

Direct integration and curve fitting techniques constitute the two main methods of peak area measurement. Simulated Ni 2p spectra are used to compare the effectiveness of the simple integral and linear background profiles for producing the correct peak areas. Although the simple integral profile shows more consistency and is to be preferred in general, certain fortuitous cancellation effects, particularly with non-monochromatized spectra, make areas using the linear background fairly accurate in some instances. Curve fitting can overcome many of the problems of direct integration resulting from severe peak overlap. Two types of Gaussian/Lorentzian functions with a suitable exponential tailing function, which has a finite area over reasonable integration limits, are discussed with regard to their use in non-linear least-squares curve fitting methods. Also discussed is the usefulness of composite and difference spectra as simpler methods of determining the relative areas of overlapping peaks.
Deformation Studies of Polymers by Time-Resolved Infrared Spectroscopy IV: A Modified Approach
Authors: Molis S. E. , MacKnight W. J. , Hsu S. L.
Published: July 2005

Recent studies have demonstrated how effective the time-resolved Fourier transform spectroscopic technique is in obtaining dynamic information about microstructural change in the millisecond time scale. In this current study, the time efficiency of the method has been improved by the development of a scheme implementing the use of a separate microprocessor to maintain synchronization between the interferometer movement and the external event. This method eliminates the need for accurate external timing circuits and their interface to the FT-IR. Therefore, data collection software of the FT-IR system need not be modified as in previous cases.
Characterization of Lubricants Using 31P Fourier Transform Nuclear Magnetic Resonance Spectroscopy
Authors: Marshall G. L.
Published: July 2005

31P Fourier transform nuclear magnetic resonance spectroscopy has been used to characterise phosphorus-containing additives used in lubricants. Quantitative and qualitative data can be obtained with the use of new and used oils that have been subjected to standard Cortina and Petter W1 engine tests. The chemistry of additive degradation during engine testing is discussed in connection with recent theories of the mechanism of engine protection.
Enhancement of the Atomic Absorption of Iodine in Hydrogen-Entrained Air Flames
Authors: Klein M. A. , Heithmar E. M.
Published: July 2005

Hydrogen-entrained air flames diluted with either argon or nitrogen are used to atomize iodine in aqueous solutions. The iodide ion present in the sample is oxidized to elemental iodine with acidic dichromate before being aspirated into the flame. Sensitivity (concentration I− per 1% absorption) in either flame after preliminary oxidation is about 0.6 ppm with a 10-cm single slot burner. Sensitivity without addition of the acidic dichromate reagent is about 150 ppm. Either hydrogen-entrained air flame yields absorbance value about eight times greater than those obtained with a fuel-rich air-acetylene flame when the iodide is oxidized to elemental iodine.
A New Method for Obtaining Individual Component Spectra from Those of Complex Mixtures
Authors: Honigs D. E. , Hieftje G. M. , Hirschfeld T.
Published: July 2005

In near-infrared reflectance analysis (NIRA), a computer is trained to recognize and quantitate the relationship between the near-infrared spectrum of a sample and the concentrations of one or more of the sample constituents. During this training process the computer implicitly generates the spectrum of the constituents in question, although this spectrum is ordinarily not available for operator inspection. In the present study, a method for displaying this implicit information is developed and evaluated. The resulting “reconstructed spectrum” can be of a specific chemical constituent in a sample or can be a composite spectrum of those components that collectively contribute to specific sample properties such as material strength or processing temperature, or to sensory characteristics such as the “hotness” of peppers. A comparison is made of this new spectral reconstruction technique to established methods such as spectral stripping and factor analysis.
Vibrational Circular Dichroism Measurements by Optical Subtraction FT-IR Spectrometry
Authors: Yang Wang-Jih , Griffiths Peter R. , Kemeny Gabor J.
Published: July 2005

The principles of dual-beam FT-IR vibrational circular dichroism (VCD) spectrometry are described. Results from this technique are presented and compared to the results from double modulation FT-IR spectrometry. Performance of dual-beam FT-IR VCD measurements are evaluated for signal-to-noise ratio and optical alignment. The use of Fresnel rhombs for mid-infrared circular dichroism spectrometry is described for the first time.
Selectively Excited Luminescence in GaAs
Authors: Bohn P. W. , Harris T. D. , Bhat R. , Cox H. M.
Published: July 2005

Relaxation of donor and acceptor bound excitons, (D°, X) and (A°, X), to a final state in which the impurity atoms are left in an internally excited state has been used in several laboratories as a tool in assigning the chemical identity of the impurity species. In many specific samples, however, this excited final state emission is obscured by the free to bound (e−, A°) or an interfering donor to acceptor (D°, A°) transition. Enhanced emission from excited final state relaxation processes in GaAs has been observed using selective excitation to increase the population of the appropriate initial states. Increases in emission intensity of approximately 8 for (D°, X)* and 30 for (A°, X)* were observed. The excitation wavelength dependence of the enhancement is explained in terms of instrumental parameters and free exciton absorption.

The converse of the selective excitation experiment was performed in order to learn more about the mechanisms which populate the levels giving rise to the analytically interesting emission. Anti-Stokes emission was observed in the near-gap region in high purity GaAs for the first time. The emission intensity as a function of excitation wavelength data is discussed in terms of a simple parallel pathway model for upconversion. The model postulates two parallel mechanisms which may populate the emitting states, and the access to one or the other of the two is determined by the energy of the incident photon. The model explains both the absolute intensity behavior of the (D°, X) and (D+, X) emission and the intensity ratio trend as a function of excitation wavelength.
Fiber Optics Expand the Range of a Direct-Reading Spark Optical Emission Spectrometer
Authors: Mills J. C. , Hodges R. J.
Published: July 2005

A quartz optical fiber flexible light conductor conveys light from the analytical gap of a vacuum optical emission spectrometer to a secondary monochromator, to extend the range of wavelengths available and enhance the versatility of operation. A simple modification to the spark stand is described. Results are given for the determination of alkali elements in mineral and ash samples. Examples of use of the enhanced versatility are discussed.
The Determination of Selenium and Tellurium in Stainless Steel, White Cast Iron, and Nickel Base Alloy Standard Reference Materials by Isotope Dilution Spark Source Mass Spectrometry
Authors: Kingston H. M. , Paulsen P. J. , Lambert G.
Published: July 2005

Procedures using stable isotope dilution spark source mass spectrometry were developed for the simultaneous determination of selenium and tellurium in stainless steels, white cast irons, and nickel based alloys. The selenium and tellurium were reduced using hypophosphorous acid except in the nickel based alloy where electrodeposition onto gold was also used for tellurium. A gold carrier was used to scavenge the selenium and tellurium efficiently during reduction. The samples were homogenized with gold and introduced into the mass spectrometer as electrodes. The concentrations calculated from the general isotope dilution equation ranged from 0.14 μg/g for selenium to 353 μg/g for tellurium. The materials tested were ten different Standard Reference Materials available from the NBS.
Gas Phase Temperatures in Massmann Furnaces Equipped with L'vov Platforms
Authors: Siemer Darryl D. , Lundberg Erik , Frech Wolfgang
Published: July 2005

The temperature of gaseous lead atoms in a Massmann furnace equipped with a L'vov platform was measured as a function of the distance above the platform. Under typical operating conditions the temperature of analyte atoms at the surface of the platform is several hundred degrees lower than is that of atoms at the walls of the tube. The magnitude of this temperature gradient depends upon both the mass and area of the platform and the heating rate of the tube containing it. L'vov platforms serve to raise the average gas phase temperature experienced by the analyte but do so by creating nonhomogeneous conditions across the optical axis and causing a loss of direct control of the sample volatilization process.
Objective Criteria for Absorbance Subtraction
Authors: Gillette P. C. , Koenig J. L.
Published: July 2005

Using an iterative linear least-squares algorithm it is possible to selectively subtract known spectral components from a mixture in an automated procedure. The proposed approach circumvents the subjective decisions encountered with interactive real-time graphics programs and enables simultaneous removal and/or optimization of scaling coefficients of multiple known pure components in order to yield the difference spectrum.
Robust Smoothing Applied to White Noise and Single Outlier Contaminated Raman Spectra
Authors: Bussian Bernd-M. , Härdle Wolfgang
Published: July 2005

There are several smoothing procedures for spectral data which are affected by occasionally occurring outliers. Most of the known methods are based on local averages (or fits) of the spectral data. We introduce here an outlier-insensitive, robust smoothing method which rejects the influence of huge noise spikes. The proposed smoothing algorithm can be tuned by two parameters. The first corresponds to the signal-to-noise ratio, the second to the halfwidths of the spectral bands. We apply this new technique to several spectra and prove the advantages of our method of identifying peaks and baselines in Raman spectroscopy.
Three-dimensional imaging of cement microstructure evolution during hydration
Authors: Helfen L. , Dehn F. , Mikulík P. , Baumbach T.
Published: July 2005

Synchrotron radiation is used for X-ray computed tomography to characterise the hydration process of Portland cement. Quantitative determination of the three-dimensional absorption coefficient distribution due to the use of monochromatic radiation and the achieved high spatial resolution allows the study of the spatial microstructure of cement volume during hydration. The present study has demonstrated the potential of the method for real-time imaging of the evolution of cement structure after solidification. The method yields three-dimensional (3-D) images of the sample volume in a non-destructive manner. Thus, by reiterated imaging of the same sample region at different times, processes in the sample volume can be tracked. During cement hydration, effects such as the formation and further evolution of microcracks and pores – mainly related to autogeneous shrinkage – could be observed for the first time in the cement volume with up to 1 μm resolution. Image analysis of the acquired 3-D data sets allows the determination of the temporal evolution of microporosity and of the fraction of contiguous pore volume for different water : cement ratios of the initial cement paste.
Efficiency of fly ash in cementitious materials
Authors: Long G. Ch. , Xie Y. J. , Jiang Z. W.
Published: July 2005

A quantitative understanding of the efficiency of fly ash as a mineral admixture in cement-based materials is essential for its effective utilisation. The present paper is directed towards a specific understanding of the efficiency of fly ash in cementitious materials systems by considering the independency of fly ash and its dependency on the characteristics of the cementitious materials system. A new method of quantitatively evaluating the strength effect of fly ash is proposed, in which two parameters, the strength-effect index and the strengthening factor, are employed to study strength development in fly ash mortars and concretes and to further analyse the influences of water to binder ratio (w/b) and the replacement amount of fly ash on strength. Results indicate that the strength effect of fly ash in mortar systems is different from that in concrete; the strength effect of fly ash varies with both amount of fly ash and w/b. Furthermore, in a concrete system, two different optimal w/b ratios are used to maximise the strength-effect index and the strengthening factor of fly ash, respectively. An optimum amount of fly ash exists for an optimal unit strength-effect index in concrete. It is shown that the method presented in this paper is reasonable and effective in assessing the efficiency of fly ash. This information will strengthen the effective utilisation of fly ash in cementitious materials and design of fly ash concrete.
Neural network modelling of properties of cement-based materials demystified
Authors: El-Chabib H. , Nehdi M.
Published: July 2005

Engineers often have to deal with materials of ill-defined behaviour such as cement-based materials in order to perform special design tasks. There is usually great difficulty in predicting the engineering properties of such materials due to various factors, including their non-homogeneous nature, their composite behaviour with dissimilar ingredients and sometimes the dual and/or contradictory effects of some components on the overall performance. Until recently, the methods used to predict the engineering properties of cement-based materials have been based mainly on statistical and mathematical models, which in turn are derived from human observation, empirical relationships and assumptions with limited ability to account for the effects of and interaction between all variables involved. An alternative approach, termed artificial neural networks (ANNs), has recently emerged in different engineering fields as a popular tool to predict the behaviour of materials. Due to the relatively recent adoption of ANNs for modelling the behaviour of cement-based materials, a good understanding of its fundamental basis and a critical assessment of its performance are essential. This paper examines the most widely used ANNs in materials modelling (the feed-forward, back-propagation (FFBP) neural networks). Guidelines for building, training, and validating such networks are provided. A critical assessment is presented of the effects of various parameters on the training and performance of FFBP networks and their use as an alternative approach to traditional modelling methods is evaluated through a case study. Recommendations are made to optimise the performance of ANNs.
Magnetic resonance imaging study in older fragile X premutation male carriers
Authors: Loesch Danuta Z. , Litewka Lucas , Brotchie Peter , Huggins Richard M. , Tassone Flora , Cook Mark
Published: July 2005

Some carriers of a “premutation” allele of the FMR1 gene develop late‐onset tremor/ataxia. We conducted a magnetic resonance imaging volumetric study in an unselected sample of eight older male premutation carriers. Volumetric measures, including total brain volume, and the volumes of cerebrum, cerebellum, and cerebral cortex all were significantly reduced in premutation carriers compared with similar data from 21 age‐matched normal controls. Total brain and cerebral volumes were significantly related to the number of CGG repeats in the FMR1 gene. Moreover, increased hippocampal volume indicates this premutation may account for both neurodegenerative and neurodevelopmental changes. Ann Neurol 2005;58:326–330
Chromosome 1p loss: A favorable prognostic factor in low‐grade gliomas
Authors: Kujas Michèle , Lejeune Julie , Benouaich‐Amiel Alexandra , Crinière Emmanuelle , Laigle‐Donadey Florence , Marie Yannick , Mokhtari Karima , Polivka Marc , Bernier Michèle , Chretien Fabrice , Couvelard Anne , Capelle Laurent , Duffau Hugues , Cornu Philippe , Broët Philippe , Thillet Joëlle , Carpentier Antoine F. , Sanson Marc , Hoang‐Xuan Khê , Delattre Jean‐Yves
Published: July 2005

Search for loss of heterozygosity on chromosomes 1p, 9p, 10q, and 19q, epidermal growth factor receptor (EGFR) gene amplification, and p53 expression was performed in a series of 131 low‐grade gliomas. The profile of molecular changes, clinical findings, and histology were subsequently correlated with the course of the disease, mainly progression‐free survival. When these parameters were considered as candidate variables in a multivariate analysis, only loss of heterozygosity on chromosome 1p was associated with increased progression‐free survival (hazard ratio, 0.521), indicating a major favorable prognostic role of this genetic alteration in low‐grade gliomas. Ann Neurol 2005;58:322–326
Xenon and hypothermia combine to provide neuroprotection from neonatal asphyxia
Authors: Ma Daqing , Hossain Mahmuda , Chow Andre , Arshad Mubarik , Battson Renee M. , Sanders Robert D. , Mehmet Huseyin , Edwards A. David , Franks Nicholas P. , Maze Mervyn
Published: July 2005

Perinatal asphyxia can result in neuronal injury with long‐term neurological and behavioral consequences. Although hypothermia may provide some modest benefit, the intervention itself can produce adverse consequences. We have investigated whether xenon, an antagonist of the N‐methyl‐D‐aspartate subtype of the glutamate receptor, can enhance the neuroprotection provided by mild hypothermia. Cultured neurons injured by oxygen‐glucose deprivation were protected by combinations of interventions of xenon and hypothermia that, when administered alone, were not efficacious. A combination of xenon and hypothermia administered 4 hours after hypoxic‐ischemic injury in neonatal rats provided synergistic neuroprotection assessed by morphological criteria, by hemispheric weight, and by functional neurological studies up to 30 days after the injury. The protective mechanism of the combination, in both in vitro and in vivo models, involved an antiapoptotic action. If applied to humans, these data suggest that low (subanesthetic) concentrations of xenon in combination with mild hypothermia may provide a safe and effective therapy for perinatal asphyxia. Ann Neurol 2005;58:182–193
Trophic factor distribution predicts functional recovery in parkinsonian monkeys
Authors: Gash Don M. , Zhang Zhiming , Ai Yi , Grondin Richard , Coffey Robert , Gerhardt Greg A.
Published: July 2005

Glial cell line–derived neurotrophic factor (GDNF) promotes the survival, growth, and regeneration of dopamine neurons in the midbrain that degenerate in Parkinson's disease. However, translating successful animal studies into effective clinical therapy for Parkinson's disease has proved difficult. In this article, using pulsed infusion for convection‐enhanced delivery of GDNF, we have analyzed two variables hypothesized to be important for achieving efficacy: dose and GDNF distribution in the target tissue. Motor functions were significantly improved in rhesus monkeys with unilateral 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine–induced parkinsonism that received midbrain infusion of GDNF for 10 weeks. The volume of distribution of GDNF in the five trophic factor recipients varied more than fivefold, from 59 to 325 mm3, and significantly correlated with motor function improvements. Significant increases were evident in the number of midbrain dopamine neurons immunopositive for tyrosine hydroxylase in both the substantia nigra and ventral tegmental area. Based on neurochemical and quantitative morphological measures, GDNF administration promoted recovery of both the nigrostriatal and ventral tegmental area–nucleus accumbens dopaminergic pathways without producing evident side effects. Increasing the dose threefold did not increase efficacy, suggesting that after achieving a critical threshold, GDNF tissue distribution is more important than dose for trophic stimulation of dopamine neurons. Ann Neurol 2005;58:224–233
Clinical and genetic spectrum of pyruvate dehydrogenase deficiency: Dihydrolipoamide acetyltransferase (E2) deficiency
Authors: Head Rosemary A. , Brown Ruth M. , Zolkipli Zarazuela , Shahdadpuri Raveen , King Mary D. , Clayton Peter T. , Brown Garry K.
Published: July 2005

Pyruvate dehydrogenase deficiency is a major cause of primary lactic acidosis and neurological dysfunction in infancy and early childhood. Most cases are caused by mutations in the X‐linked gene for the E1α subunit of the complex. Mutations in DLAT, the gene encoding dihydrolipoamide acetyltransferase, the E2 core component of the complex, have not been described previously. We report two unrelated patients with pyruvate dehydrogenase deficiency caused by defects in the E2 subunit. Both patients are less severely affected than typical patients with E1α mutations and both have survived well into childhood. Episodic dystonia was the major neurological manifestation, with other more common features of pyruvate dehydrogenase deficiency, such as hypotonia and ataxia, being less prominent. The patients had neuroradiological evidence of discrete lesions restricted to the globus pallidus, and both are homozygous for different mutations in the DLAT gene. The clinical presentation and neuroradiological findings are not typical of pyruvate dehydrogenase deficiency and extend the clinical and mutational spectrum of this condition. Ann Neurol 2005;58:234–241
Cerebral gene expression profiles in sporadic Creutzfeldt–Jakob disease
Authors: Xiang Wei , Windl Otto , Westner Ingo M. , Neumann Manuela , Zerr Inga , Lederer Rosa M. , Kretzschmar Hans A.
Published: July 2005

The pathomechanism of sporadic Creutzfeldt–Jakob disease (sCJD) in the central nervous system is insufficiently understood. The aims of this study were to identify differentially regulated genes in the frontal cortex of sCJD and to profile the gene expression patterns in sCJD by using Affymetrix HGU133A microarrays (Affymetrix, Santa Clara, CA). The microarray data were generated by dChip and analyzed by Significance Analysis of Microarray (SAM) software. A comparison between control and sCJD samples identified 79 upregulated and 275 downregulated genes, which showed at least 1.5‐ and 2‐fold changes, respectively, in sCJD frontal cortex, with an estimated false discovery rate of 5% or less. The major alterations in sCJD brains included upregulation of the genes encoding immune and stress‐response factors and elements involved in cell death and cell cycle, as well as prominent downregulation of genes encoding synaptic proteins. A comparison of the molecular subtypes of sCJD showed various expression patterns associated with particular subtypes. The range of the upregulated genes and the degree of the increased expression appeared to be correlated with the degree of the neuropathological alterations in particular subtypes. Conspicuously, sCJD brains showed a great similarity with ageing human brains, both in the global expression patterns and in the identified differentially expressed genes. Ann Neurol 2005;58:242–257
Manganese porphyrin given at symptom onset markedly extends survival of ALS mice
Authors: Crow John P. , Calingasan Noel Y. , Chen Junyu , Hill Julie Lynch , Beal M. Flint
Published: July 2005

Mice that overexpress the human Cu,Zn superoxide dismutase‐1 mutant G93A develop a delayed and progressive motor neuron disease similar to human amyotrophic lateral sclerosis (ALS). Most current studies of therapeutics in these mice to date have involved administration of agents long before onset of symptoms, which cannot currently be accomplished in human ALS patients. We examined the effects of the manganese porphyrin AEOL 10150 (manganese [III] tetrakis[N‐N′‐diethylimidazolium‐2‐yl]porphyrin) given at symptom onset and found, in three separate studies, that it extended the survival after onset up to 3.0‐fold. Immunohistochemical analysis of spinal cord for SMI‐32, an abundant protein in motor neurons, indicated better preservation of motor neuron architecture, less astrogliosis (glial fibrillary acidic protein), and markedly less nitrotyrosine and malondialdehyde in porphyrin‐treated spinal cords relative to vehicle‐treated mice. These results show that the catalytic antioxidant AEOL 10150 provides a pronounced therapeutic benefit with onset administration and is, therefore, a promising agent for the treatment of ALS. Ann Neurol 2005;58:258–265
Adult‐onset ataxia and polyneuropathy caused by mitochondrial 8993T→C mutation
Authors: Rantamäki Maria T. , Soini Heidi K. , Finnilä Saara M. , Majamaa Kari , Udd Bjarne
Published: July 2005

The 8993T→C mutation in mitochondrial DNA (mtDNA) has been described previously to be associated with infantile‐ or childhood‐onset phenotypes, ranging from Leigh's syndrome to neurogenic weakness, ataxia, and retinitis pigmentosa syndrome. We report a kindred with adult‐onset slowly progressive ataxia and polyneuropathy and with the heteroplasmic 8993T→C mutation. Our findings suggest that the 8993T→C mtDNA mutation should be considered in the differential diagnosis of nondominant adult‐onset ataxia and axonal neuropathy. Ann Neurol 2005;58:337–340
Sickle cell disease: Ischemia and seizures
Authors: Prengler Mara , Pavlakis Steven G. , Boyd Stewart , Connelly Alan , Calamante Fernando , Chong W. K. , Saunders Dawn , Cox Timothy , Bynevelt Michael , Lane Roderick , Laverty Aidan , Kirkham Fenella J.
Published: July 2005

Although the prevalence of seizures in children with sickle cell disease (SCD) is 10 times that of the general population, there are few prospectively collected data on mechanism. With transcranial Doppler and magnetic resonance imaging (MRI) and angiography, we evaluated 76 patients with sickle cell disease, 29 asymptomatic and 47 with neurological complications (seizures, stroke, transient ischemic attack, learning difficulty, headaches, or abnormal transcranial Doppler), who also underwent bolus‐tracking perfusion MRI. The six patients with recent seizures also had electroencephalography. Group comparisons (seizure, nonseizure, and asymptomatic) indicated that abnormal transcranial Doppler was more common in the seizure (4/6; 67%) and nonseizure (26/41; 63%) groups than in the asymptomatic (10/29; 34%) group (χ2;p= 0.045), but abnormal structural MRI (χ2;p= 0.7) or magnetic resonance angiography (χ2;p= 0.2) were not.Relativedecreased cerebral perfusion was found in all seizure patients and in 16 of 32 of the remaining patients with successful perfusion MRI (p= 0.03). In the seizure patients, the perfusion abnormalities in five were ipsilateral to electroencephalographic abnormalities; one had normal electroencephalogram results. These findings suggest that vasculopathy and focal hypoperfusion may be factors in the development of sickle cell disease–associated seizures. Ann Neurol 2005;58:290–302
Noisy vestibular stimulation improves autonomic and motor responsiveness in central neurodegenerative disorders
Authors: Yamamoto Yoshiharu , Struzik Zbigniew R. , Soma Rika , Ohashi Kyoko , Kwak Shin
Published: July 2005

The vestibular nerves are known to influence neuronal circuits in the medullary cardiovascular areas and, through the cerebellar vermis, the basal ganglia and the limbic system. By means of noisy galvanic vestibular stimulation (GVS), it might be possible to ameliorate blunted responsiveness of degenerated neuronal circuits of patients with multi system atrophy or Parkinson's disease, or both. We evaluated the effect of 24‐hour noisy GVS on long‐term heart rate dynamics in 7 patients with multi system atrophy and on daytime trunk activity dynamics in 12 patients with either levodopa‐responsive Parkinson's disease or levodopa‐unresponsive parkinsonism. Six of the latter patients were also examined for cognitive performance by means of a continuous performance test. Short‐range or high‐frequency fluctuations of heart rate were significantly increased by the noisy GVS compared with sham stimulation, suggestive of improved autonomic, especially parasympathetic, responsiveness. Long‐range antipersistency of trunk activity patterns probed by an autocorrelation measure was significantly increased by the noisy GVS, suggestive of quickening of bradykinesic rest‐to‐active transitions. The mean reaction time of the continuous performance test was also significantly decreased by the noisy GVS, without significant changes in either the omission or commission error ratios, which is suggestive of improved motor execution during the cognitive task. In conclusion, the noisy GVS is effective in boosting the neurodegenerative brains of patients with multi system atrophy or Parkinson's disease, or both, including those unresponsive to standard levodopa therapy; it is also effective in improving these patients' autonomic and motor responsiveness. Ann Neurol 2005;58:175–181
Antibacterial activity of chitosan–alginate sponges incorporating silver sulfadiazine: Effect of ladder‐loop transition of interpolyelectrolyte complex and ionic crosslinking on the antibiotic release
Authors: Yu Shu‐Huei , Mi Fwu‐Long , Wu Yu‐Bey , Peng Chih‐Kang , Shyu Shin‐Shing , Huang Rong‐Nan
Published: July 2005

Hydrogel membranes prepared from polyelectrolyte complex (PEC) have been used for repair of wounds and controlled antibacterial release. A simple method, based on homogenizing interpolyelectrolyte complex, has been developed to prepare a chitosan–alginate sponge with high stability. The spongelike chitosan–alginate hydrogel can be used as a wound dressing for the sustained release of silver sulfadiazine (AgSD) in a controlled way. In this study, we evaluated the effect of electrolyteic properties of chitosan and alginate on the characteristics of the prepared chitosan–alginate PEC. All types of the spongelike chitosan–alginate hydrogels exhibited superabsorbent properties. However, only the chitosan–alginate hydrogel prepared by the interpolyelectrolyte complex of alginate with low pH of chitosan, and that prepared by the interpolyelectrolyte complex of chitosan with high pH of alginate, can keep their stability after swelling in PBS solution. FTIR analysis suggests that the protonated amino groups on chitosan and the ionized carboxylic groups on alginate should be responsible for the formation of a stable ladder‐type of chitosan–alginate PEC. Ionic crosslinking is helpful to increase the stability of the loop‐type of chitosan–alginate PEC. The release of AgSD from chitosan–alginate PEC sponges could be controlled by the variation of ladder‐loop structural transition of chitosan–alginate PEC and the ionic crosslinking of the chitosan–alginate complex. The antibacterial ability of AgSD‐incorporated PEC sponges was examined in agar plate against Pseudomonas aeruginosa and Staphylococcus aureus. The result suggests that the PEC sponges containing antimicrobial agents should effectively suppress bacterial proliferation to protect the wound from bacterial invasion. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 538–549, 2005
Physics and kinetics of alkaline hydrolysis of cationic dyeable poly(ethylene terephthalate) (CDPET) and polyethylene glycol (PEG)–modified CDPET polymers: Effects of dimethyl 5‐sulfoisophthalate sodium salt/PEG content and the number‐average molecular weight of the PEG
Authors: Hsiao Kai‐Jen , Kuo Jen‐Liang , Tang Jing‐Wen , Chen Lien‐Tai
Published: July 2005

This study investigated the physics and kinetics of three cationic dyeable poly(ethylene terephthalate) (CDPET) and four polyethylene glycol (PEG)–modified cationic dyeable PET (PEG‐modified CDPET) polymers using differential scanning calorimetry, thermogravimetric analysis, the density gradient method, gel permeation chromatography, a rheometer, and statistical regression analysis. The molar ratios of dimethyl 5‐sulfoisophthalate sodium salt (SIPM) for three CDPET polymers were 2, 6, and 10%, respectively. For four PEG‐modified CDPET polymers, with molar ratios of SIPM of 2%, the PEG content and the number‐average molecular weights (Mn) of PEG were 3/6 (wt %) and 400/2000 (g/mol), respectively. Experimental results revealed that the crystallinities of CDPET and PEG‐modified CDPET polymers declined as the SIPM and PEG contents increased. The crystallinity of the PEG400–CDPET polymer exceeded that of the PEG2000–CDPET polymer with the same SIPM and PEG contents. The SIPM and PEG segments did not change the original PET unit cell. The SO3Na functional group and the PEG molecules gathered only on the crystal surface and in the amorphous regions. In the kinetic equation of the alkaline hydrolysis of PET, CDPET, and PEG‐modified CDPET polymers, β equals 1. Furthermore, the R2 of the kinetic equation for α from 1.09 to 1.25 was better than that of α = 1. The rate constants of alkaline hydrolysis were in the order CDPET‐10 > CDPET‐6 > PEG2000‐6‐CDPET‐2 > PEG2000‐3‐CDPET‐2 > PEG400‐6‐CDPET‐2 > PEG400‐3‐CDPET‐2 > CDPET‐2 > PET. Clearly, the rate constant of the alkaline hydrolysis of CDPET and PEG‐modified CDPET polymers increased with SIPM/PEG content and the Mn of the PEG increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 550–556, 2005
Comparison and evaluation of the thermooxidative stability of medical natural rubber latex products prepared with a sulfur vulcanization system and a peroxide vulcanization system
Authors: Chen Mei , Ao Ning‐Jian , Zhang Bei‐Long , Den Chun‐Mei , Qian Hong‐Lian , Zhou Hui‐Ling
Published: July 2005

This article deals with our study of the thermooxidative degradation of medical natural rubber latex tubes prepared with sulfur‐prevulcanized latex (sample I) and peroxide‐prevulcanized latex (sample II) in a dynamic air atmosphere by the use of the thermogravimetry/differential thermogravimetry method as well as the evaluation of the thermooxidative stability of these two samples. The test results showed that an oxygen‐absorption mass‐gain process occurred after a slight mass loss; the mass‐gain rate decreased with an increase in the temperature rising rate (β), and this was more prominent in sample II than in sample I. The maximum mass‐gain rate of sample II was 1.43% when β was 5°C/min, which was 5.02 times that of sample I; the thermooxidative stability of sample II was also lower than that of sample I. Because the oxygen absorption of sample II clearly caused serious oxidation, the balanced initial temperature, the temperature of the balanced degradation peak, and the balanced final temperature of sample II in the first reaction stage were obviously lower than those of sample I. The apparent activation energy (Eo = 143.6 kJ/mol) of sample I was significantly higher than that of sample II, and the stability of sample I was also higher than that of sample II. The temperature of the balanced degradation peak of sample II in the second reaction stage was higher than that of sample I, and Eo (154.0 kJ/mol) of sample II was significantly higher than that of sample I; the stability of sample II was also higher. Thermogravimetry curves of the two samples at various β values intercrossed each other, and the temperature at the crosspoint and the degradation rate increased linearly as β increased. On the temperature segment from the initial temperature to the crosspoint, the degradation rate of sample II was higher than that of sample I when the temperature of the two samples was the same, but on the segment from the crosspoint to the final temperature, the degradation rate of sample II was lower than that of sample I when the temperature of the two samples was the same. The degradation rate of the samples at 600°C was 99.2–99.5%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 591–597, 2005
Binding of chlorpheniramine maleate to pharmacologically important alginic acid, carboxymethylcellulose, κ‐carageenan, and ι‐carrageenan as studied by diafiltration
Authors: Moreno‐Villoslada Ignacio , Oyarzún Felipe , Miranda Víctor , Hess Susan , Rivas Bernabé L.
Published: July 2005

The binding of cationic chlorpheniramine maleate (CPM) to the anionic water‐soluble polymers (WSPs) alginic acid, carboxymethylcellulose, κ‐carageenan, and ι‐carageenan was evaluated by diafiltration at pH 7.5 and in the absence and presence of 0.13M NaCl. CPM interacted with all of the WSPs when no NaCl was present in the solution, with charge‐related formation constants of around 700 M−1 for all of the polymers, whereas the interactions were cleaved in the presence of 0.13M NaCl, indicating interactions of an electrostatic nature screened by the single electrolyte. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 598–602, 2005
Short beam three point bend tests in syntactic foams. Part I: Microscopic characterization of the failure zones
Authors: Kishore  , Shankar Ravi , Sankaran S.
Published: July 2005

Scanning Electron Microscopic (SEM) studies were carried out on the failure surface of syntactic foam material tested in a short beam three point bend test (SBT) by employing 21 × 15 × 3 mm3 dimension bearing specimens. The syntactic foams were fabricated using glass microballoons in epoxy binder. The failure of the tensile, compression, and shear dominated regions were studied by SEM at different magnifications. The tensile region had characteristic features, such as partial debonding of the microballoons from the matrix and cracking of glass microballoons, apart from matrix cracking and some river pattern features. The compression side was characterized by crushing and collapsing of microballoons, resulting in accumulation of debris with no apparent river pattern for matrix‐rich regions. The midway positions of the SBT failed surface comprised of deformation bands in the matrix and occasional debonding of microballoons. The morphology recorded in the tensile and compression regions corroborated well with the results obtained on these foam samples in those specimens that were subjected to pure uniaxial tension and compression, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 673–679, 2005
Short‐beam three‐point bend tests in syntactic foams. Part II: Effect of microballoons content on shear strength
Authors: Kishore  , Shankar Ravi , Sankaran S.
Published: July 2005

Epoxy binders containing microballoons ranging from 38.5 to 57.7% by volume were cast in a mold and cured, and the resulting slabs were sectioned to yield short‐beam test coupons. The strength changes with microballoons content were noted. These reveal an increase from 3.87 to 5.79 MPa for a decrease in microballoons content from 57.7 to 38.5%. Mechanical data were correlated with fractographic features employing scanning electron microscope. The failure features involving the microballoons and interface regions are highlighted in this article. The works show the existence of a dependence of strength parameters on the inter‐microballoon distances. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 680–686, 2005
Treatment of rheumatoid arthritis with the selective costimulation modulator abatacept: Twelve‐month results of a phase iib, double‐blind, randomized, placebo‐controlled trial
Authors: Kremer Joel M. , Dougados Maxime , Emery Paul , Durez Patrick , Sibilia Jean , Shergy William , Steinfeld Serge , Tindall Elizabeth , Becker Jean‐Claude , Li Tracy , Nuamah Isaac F. , Aranda Richard , Moreland Larry W.
Published: July 2005

Objective

To determine the clinical efficacy, safety, and immunogenicity of abatacept (CTLA‐4Ig), a selective costimulation modulator, in patients with rheumatoid arthritis (RA) that has remained active despite methotrexate (MTX) therapy.

Methods

This was a 12‐month, multicenter, randomized, double‐blind, placebo‐controlled study. A total of 339 patients with active RA despite MTX therapy were randomly assigned to receive 10 mg/kg abatacept (n = 115), 2 mg/kg abatacept (n = 105), or placebo (n = 119). This report focuses on the results observed at month 12 of a phase IIb trial.

Results

A significantly greater percentage of patients treated with 10 mg/kg abatacept met the American College of Rheumatology 20% improvement criteria (achieved an ACR20 response) at 1 year compared with patients who received placebo (62.6% versus 36.1%; P < 0.001). Greater percentages of patients treated with 10 mg/kg abatacept also achieved ACR50 responses (41.7% versus 20.2%; P < 0.001) and ACR70 responses (20.9% versus 7.6%; P = 0.003) compared with patients who received placebo. For patients treated with 10 mg/kg abatacept, there were also statistically significant and clinically important improvements in modified Health Assessment Questionnaire scores compared with patients who received placebo (49.6% versus 27.7%; P < 0.001). Abatacept at a dosage of 10 mg/kg elicited an increase in rates of remission (Disease Activity Score in 28 joints of <2.6) compared with placebo at 1 year (34.8% versus 10.1%; P < 0.001). The incidence of adverse events was comparable between the groups, and no significant formation of neutralizing antibodies was noted.

Conclusion

Abatacept was associated with significant reductions in disease activity and improvements in physical function that were maintained over the course of 12 months in patients with RA that had remained active despite MTX treatment. Abatacept was found to be well tolerated and safe over the course of 1 year. Abatacept in combination with MTX has the potential to play an important role in future RA therapy.
The smallest detectable difference and sensitivity to change of magnetic resonance imaging and radiographic scoring of structural joint damage in rheumatoid arthritis finger, wrist, and toe joints: A comparison of the omeract rheumatoid arthritis magnetic resonance imaging score applied to different joint combinations and the sharp/van der heijde radiographic score
Authors: Ejbjerg Bo Jannik , Vestergaard Aage , Jacobsen Søren , Thomsen Henrik S. , ØStergaard Mikkel
Published: July 2005

Objective

To compare 2 magnetic resonance imaging (MRI) approaches and radiographic evaluation according to the Sharp/van der Heijde method with respect to sensitivity to change in joint destruction in patients with rheumatoid arthritis (RA).

Methods

Thirty‐five RA patients and 9 healthy controls underwent MRI and radiography on 2 occasions 1 year apart. Conventional radiographs of the hands, wrists, and forefeet were evaluated according to the Sharp/van der Heijde method. MRIs of unilateral wrist and second through fifth metacarpophalangeal (MCP) joints (“few‐joints approach”) and of bilateral wrist and MCP joints plus unilateral metatarsophalangeal (MTP) joints (“many‐joints approach”) were assessed for bone erosions according to the scoring system recommended by the OMERACT (Outcome Measures in Rheumatology Clinical Trials) group. The smallest detectable differences (SDDs) of the radiography and MRI scores were computed based on reevaluation of one‐third of the study population.

Results

Progressive joint destruction, i.e., an increase in score after the followup period, was observed more frequently with the MRI “many‐joints approach” (30 subjects) and “few‐joints approach” (25 subjects) than with the Sharp/van der Heijde radiographic method (9 subjects) (P < 0.001 by chi‐square analysis). No significant difference between the MRI approaches was observed. When only subjects with a change greater than the SDD were considered, progression was revealed with the MRI “many‐joints approach,” the MRI “few‐joints approach,” and radiography in 15, 13, and 5 RA subjects, respectively. With both MRI approaches, significantly more subjects with progression were detected than were detected by radiography (P < 0.05).

Conclusion

MRI, regardless of whether it covers unilateral wrist and MCP joints or bilateral wrist and MCP joints plus unilateral MTP joints, is significantly superior to radiography of the hands, wrists, and forefeet with respect to detection of progressive joint destruction in RA.
Mechanical injury of cartilage explants causes specific time‐dependent changes in chondrocyte gene expression
Authors: Lee Jennifer H. , Fitzgerald Jonathan B. , DiMicco Michael A. , Grodzinsky Alan J.
Published: July 2005

Objective

Joint injury in young adults leads to an increased risk of developing osteoarthritis (OA) later in life. This study was undertaken to determine if injurious mechanical compression of cartilage explants results in changes at the level of gene transcription that may lead to subsequent degradation of the cartilage.

Methods

Cartilage was explanted from the femoropatellar groove of newborn calves. Levels of messenger RNA encoding matrix molecules, proteases, their natural inhibitors, transcription factors, and cytokines were assessed in free swelling control cultures as compared with cartilage cultures at 1, 2, 4, 6, 12, and 24 hours after application of a single injurious compression.

Results

Gene‐expression levels measured in noninjured, free swelling cartilage varied over 5 orders of magnitude. Matrix molecules were the most highly expressed of the genes tested, while cytokines, matrix metalloproteinases (MMPs), aggrecanases (ADAMTS‐5), and transcription factors showed lower expression levels. Matrix molecules showed little change in expression after injurious compression, whereas MMP‐3 increased ∼250‐fold, ADAMTS‐5 increased ∼40‐fold, and tissue inhibitor of metalloproteinases 1 increased ∼12‐fold above the levels in free swelling cultures. Genes typically used as internal controls, GAPDH and β‐actin, increased expression levels ∼4‐fold after injury, making them unsuitable for use as normalization genes in this study. The expression levels of tumor necrosis factor α and interleukin‐1β, cytokines known to be involved in the progression of OA, did not change in the chondrocytes after injury.

Conclusion

Changes in the level of gene expression after mechanical injury are gene specific and time dependent. The quantity of specific proteins may be altered as a result of these changes in gene expression, which may eventually lead to degradation at the tissue level and cause a compromise in cartilage structure and function.