bluuebunny/crossref_metadata_2025 huggingface dataset:
Topical immunotherapy of severe alopecia areata with diphenylcyclopropenone (DPCP): experience in an Iranian population
Authors: Aghaei Shahin
Published: May 2005

Background

Highly variable results of topical diphenylcyclopropenone (DPCP) in the treatment of alopecia areata have been reported so far. The purposes of the present study were to evaluate the efficacy and tolerability of DPCP treatment in severe alopecia areata.

Methods

Twenty-eight patients (16 female and 12 male, 10–35 years old, mean age 25 years) with extensive alopecia areata were enrolled in an open-label clinical trial. After sensitization with 2% DPCP, progressively higher concentrations beginning at 0.001% were applied weekly for 6 months to one side of the scalp, after which, if terminal hair growth was noted, the entire scalp was then treated under the same weekly protocol. The maximum concentration of DPCP in acetone was 2%.

Results

Twenty-seven of 28 patients completed therapy. The overall response rate was 81.5% (22/27), complete remission (90%-100% terminal hair re-growth) was obtained 22.2% (6/27) and partial remission (10%-90% terminal hair re-growth) in 59.3% (16/27). In all patients an eczematous reaction consisting of erythema, itching, and scaling at the site of application were observed. During therapy, other side effects including, occipital lymphadenopathy 40.7% (11/27), severe eczema/blister formation 40.7% (11/27), hyperpigmentation 18.5% (5/27) were observed, but no hypopigmentation, vitiligo, contact urticaria, and erythema multiforme-like reaction were seen in the patients. Nineteen of 27 (70.4%) patients had at least one side effect, other than eczematous reaction. Notably, partial recurrence was observed in 50.9% (13/22) of these patients after 6 to 12 months of follow-up. During the follow-up time the maintenance DPCP immunotherapy was continued.

Conclusion

Topical DPCP treatment for alopecia areata is an effective therapy with a slightly high relapse rate during bilateral maintenance treatment. According to the author's knowledge this is the first experience with DPCP in Iran.
General practitioners with a special interest in respiratory medicine: national survey of UK primary care organisations
Authors: Pinnock Hilary , Netuveli Gopalakrishnan , Price David , Sheikh Aziz
Published: May 2005

Background

To meet the universally recognised challenge of caring for people with long-term diseases many healthcare cultures are encouraging family physicians to develop specialist skills. We aimed to determine the major factors influencing the appointment of respiratory General Practitioners with a Special Interest (GPwSI) in the UK, and to determine the priority attached to the potential roles, perceived barriers to implementation, and monitoring planned.

Methods

We sent a piloted semi-structured questionnaire to a random sample of 50% of English and Welsh primary care organisations (PCOs) (n = 161) during winter 2003. In addition to descriptive statistics, we used hierarchical cluster analysis to classify service priorities. Free-text responses to open-ended questions were analysed qualitatively by a multidisciplinary group to identify emerging themes.

Results

Of the 111 (69%) PCOs who responded, 7 (6%) already have, and a further 35 (32%) are planning, a respiratory GPwSI service. This proportion is considerably lower than in specialities linked to National Health Service clinical priorities. Local needs and pressure on hospital beds were the main described motives for developing a service. Stated service priorities were to relieve pressure on secondary care and to improve quality of care, including the strategic planning of respiratory services within PCOs.

Conclusion

The relatively few respiratory GPwSIs currently in post reflects the lack of government prioritisation of respiratory care. However, respiratory GPwSI services are increasingly being considered as a local strategy for reducing pressure on secondary care respiratory services and raising standards of chronic disease management in primary care.
Development of a semi-quantitative food frequency questionnaire for use in United Arab Emirates and Kuwait based on local foods
Authors: Dehghan Mahshid , Al Hamad Nawal , Yusufali AfzalHussein , Nusrath Fathimunissa , Yusuf Salim , Merchant Anwar T
Published: May 2005

Background

The Food Frequency Questionnaire (FFQ) is one of the most commonly used tools in epidemiologic studies to assess long-term nutritional exposure. The purpose of this study is to describe the development of a culture specific FFQ for Arab populations in the United Arab Emirates (UAE) and Kuwait.

Methods

We interviewed samples of Arab populations over 18 years old in UAE and Kuwait assessing their dietary intakes using 24-hour dietary recall. Based on the most commonly reported foods and portion sizes, we constructed a food list with the units of measurement. The food list was converted to a Semi-Quantitative Food Frequency Questionnaire (SFFQ) format following the basic pattern of SFFQ using usual reported portions. The long SFFQ was field-tested, shortened and developed into the final SFFQ.

To estimate nutrients from mixed dishes we collected recipes of those mixed dishes that were commonly eaten, and estimated their nutritional content by using nutrient values of the ingredients that took into account method of preparation from the US Department of Agriculture's Food Composition Database.

Results

The SFFQs consist of 153 and 152 items for UAE and Kuwait, respectively. The participants reported average intakes over the past year. On average the participants reported eating 3.4 servings/d of fruits and 3.1 servings/d of vegetables in UAE versus 2.8 servings/d of fruits and 3.2 servings/d of vegetables in Kuwait. Participants reported eating cereals 4.8 times/d in UAE and 5.3 times/d in Kuwait. The mean intake of dairy products was 2.2/d in UAE and 3.4 among Kuwaiti.

Conclusion

We have developed SFFQs to measure diet in UAE and Kuwait that will serve the needs of public health researchers and clinicians and are currently validating those instruments.
Octacalcium phosphate crystals directly stimulate expression of inducible nitric oxide synthase through p38 and JNK mitogen-activated protein kinases in articular chondrocytes
Authors: Ea Hang-Korng , Uzan Benjamin , Rey Christian , Lioté Frédéric
Published: May 2005

Basic calcium phosphate (BCP) crystals, including hydroxyapatite, octacalcium phosphate (OCP) and carbonate-apatite, have been associated with severe osteoarthritis and several degenerative arthropathies. Most studies have considered the chondrocyte to be a bystander in the pathogenesis of calcium crystal deposition disease, assuming that synovial cell cytokines were the only triggers of chondrocyte activation. In the present study we identified direct activation of articular chondrocytes by OCP crystals, which are the BCP crystals with the greatest potential for inducing inflammation. OCP crystals induced nitric oxide (NO) production and inducible nitric oxide synthase (NOS) mRNA expression by isolated articular chondrocytes and cartilage fragments, in a dose-dependent manner and with variations over time. OCP crystals also induced IL-1β mRNA expression. Using pharmacological and cytokine inhibitors, we observed that OCP crystals induced NO production and inducible NOS mRNA activation were regulated at both the transcriptional and the translational levels; were independent from IL-1β gene activation; and involved p38 and c-Jun amino-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways, as further confirmed by OCP crystal-induced p38 and JNK MAPK phosphorylation. Taken together, our data suggest that the transcriptional inducible NOS response to OCP crystals involved both the p38 and the JNK MAPK pathways, probably under the control of activator protein-1. NO, a major mediator of cartilage degradation, can be directly produced by BCP crystals in chondrocytes. Together with synovial activation, this direct mechanism may be important in the pathogenesis of destructive arthropathies triggered by microcrystals.
Catabolic stress induces expression of hypoxia-inducible factor (HIF)-1α in articular chondrocytes: involvement of HIF-1α in the pathogenesis of osteoarthritis
Authors: Yudoh Kazuo , Nakamura Hiroshi , Masuko-Hongo Kayo , Kato Tomohiro , Nishioka Kusuki
Published: May 2005

Transcription factor hypoxia-inducible factor (HIF)-1 protein accumulates and activates the transcription of genes that are of fundamental importance for oxygen homeostasis – including genes involved in energy metabolism, angiogenesis, vasomotor control, apoptosis, proliferation, and matrix production – under hypoxic conditions. We speculated that HIF-1α may have an important role in chondrocyte viability as a cell survival factor during the progression of osteoarthritis (OA). The expression of HIF-1α mRNA in human OA cartilage samples was analyzed by real-time PCR. We analyzed whether or not the catabolic factors IL-1β and H2O2 induce the expression of HIF-1α in OA chondrocytes under normoxic and hypoxic conditions (O2 <6%). We investigated the levels of energy generation, cartilage matrix production, and apoptosis induction in HIF-1α-deficient chondrocytes under normoxic and hypoxic conditions. In articular cartilages from human OA patients, the expression of HIF-1α mRNA was higher in the degenerated regions than in the intact regions. Both IL-1β and H2O2 accelerated mRNA and protein levels of HIF-1α in cultured chondrocytes. Inhibitors for phosphatidylinositol 3-kinase and p38 kinase caused a significant decrease in catabolic-factor-induced HIF-1α expression. HIF-1α-deficient chondrocytes did not maintain energy generation and cartilage matrix production under both normoxic and hypoxic conditions. Also, HIF-1α-deficient chondrocytes showed an acceleration of catabolic stress-induced apoptosis in vitro. Our findings in human OA cartilage show that HIF-1α expression in OA cartilage is associated with the progression of articular cartilage degeneration. Catabolic-stresses, IL-1β, and oxidative stress induce the expression of HIF-1α in chondrocytes. Our results suggest an important role of stress-induced HIF-1α in the maintenance of chondrocyte viability in OA articular cartilage.
Tiling microarray analysis of rice chromosome 10 to identify the transcriptome and relate its expression to chromosomal architecture
Authors: Li Lei , Wang Xiangfeng , Xia Mian , Stolc Viktor , Su Ning , Peng Zhiyu , Li Songgang , Wang Jun , Wang Xiping , Deng Xing Wang
Published: May 2005

Background

Sequencing and annotation of the genome of rice (Oryza sativa) have generated gene models in numbers that top all other fully sequenced species, with many lacking recognizable sequence homology to known genes. Experimental evaluation of these gene models and identification of new models will facilitate rice genome annotation and the application of this knowledge to other more complex cereal genomes.

Results

We report here an analysis of the chromosome 10 transcriptome of the two major rice subspecies, japonica and indica, using oligonucleotide tiling microarrays. This analysis detected expression of approximately three-quarters of the gene models without previous experimental evidence in both subspecies. Cloning and sequence analysis of the previously unsupported models suggests that the predicted gene structure of nearly half of those models needs improvement. Coupled with comparative gene model mapping, the tiling microarray analysis identified 549 new models for the japonica chromosome, representing an 18% increase in the annotated protein-coding capacity. Furthermore, an asymmetric distribution of genome elements along the chromosome was found that coincides with the cytological definition of the heterochromatin and euchromatin domains. The heterochromatin domain appears to associate with distinct chromosome level transcriptional activities under normal and stress conditions.

Conclusion

These results demonstrated the utility of genome tiling microarray in evaluating annotated rice gene models and in identifying novel transcriptional units. The tiling microarray sanalysis further revealed a chromosome-wide transcription pattern that suggests a role for transposable element-enriched heterochromatin in shaping global transcription in response to environmental changes in rice.
Refinement and prediction of protein prenylation motifs
Authors: Maurer-Stroh Sebastian , Eisenhaber Frank
Published: May 2005

We refined the motifs for carboxy-terminal protein prenylation by analysis of known substrates for farnesyltransferase (FT), geranylgeranyltransferase I (GGT1) and geranylgeranyltransferase II (GGT2). In addition to the CaaX box for the first two enzymes, we identify a preceding linker region that appears constrained in physicochemical properties, requiring small or flexible, preferably hydrophilic, amino acids. Predictors were constructed on the basis of sequence and physical property profiles, including interpositional correlations, and are available as the Prenylation Prediction Suite (PrePS, http://mendel.imp.univie.ac.at/sat/PrePS) which also allows evaluation of evolutionary motif conservation. PrePS can predict partially overlapping substrate specificities, which is of medical importance in the case of understanding cellular action of FT inhibitors as anticancer and anti-parasite agents.
Impact of Managed Care on Cancer Trial Enrollment
Authors: Gross C.P. , Krumholz H.M.
Published: May 2005

Purpose

To determine the relationship between managed care market activity and cancer trial enrollment.

Methods

Trial participant data were obtained from the National Cancer Institute. Participants in cooperative group trials of breast, colorectal, lung, or prostate cancer during the years 1996 through 2001 were assigned to counties based on their zip code of residence. Linear regression was used to determine the relationship between county enrollment rate and two measures of county managed care activity (penetration and index of competition [IOC]), adjusting for other county characteristics.

Results

In bivariate analysis, there was a strong inverse correlation between trial enrollment rate and IOC (r = −0.23; P < .001) as well as the proportion of the population uninsured (−0.31; P < .001) and the percentage below poverty (−0.16; P < .001). In the multivariate model, greater county managed care competition (IOC) was inversely related to trial enrollment rate (P < .008 for comparison of each quartile v lowest quartile) after accounting for managed care penetration, proportion uninsured, and other county characteristics. Counties in the lowest quartile of managed care penetration tended to have lower enrollment rates than the remaining counties (r = −0.05; P = .048), while counties in the second, third, and fourth quartiles of penetration all had similar enrollment rates to one another.

Conclusion

Cancer trial enrollment rates were suboptimal across all counties, and counties with higher levels of managed care competition had significantly lower enrollment rates. The relationship between managed care penetration and trial enrollment was less consistent. Future efforts to enhance trial participation should address the potential negative influence of market factors.
The Telomerase Activity of Adult Mouse Testis Resides in the Spermatogonial α6-Integrin-Positive Side Population Enriched in Germinal Stem Cells
Authors: Riou Lydia , Bastos Henri , Lassalle Bruno , Coureuil Mathieu , Testart Jacques , Boussin François D. , Allemand Isabelle , Fouchet Pierre
Published: May 2005

Testis is one of the organs with the most telomerase activity in the adult. This activity protects chromosomes from telomere attrition and ensures the transmission of full-length chromosomes to progeny. Little is known about telomerase activity during adult germ cell differentiation, however. We demonstrate here that the telomerase activity of adult mouse testis resides in the α6-integrin-positive Side Population containing spermatogonia and enriched in spermatogonial stem cells. The telomerase activity of these cells fell upon entry into meiosis and during the subsequent spermiogenesis. In addition, the telomerase activity of cells in various stages of differentiation was unaffected by aging and, notably, remained high in the α6-integrin-positive Side Population.
Molecular Pathogenesis of Euthyroid and Toxic Multinodular Goiter
Authors: Krohn Knut , Führer Dagmar , Bayer Yvonne , Eszlinger Markus , Brauer Volker , Neumann Susanne , Paschke Ralf , Führer-Sakel Dagmar
Published: May 2005

The purpose of this review is to summarize current knowledge of the etiology of euthyroid and toxic multinodular goiter (MNG) with respect to the epidemiology, clinical characteristics, and molecular pathology.

In reconstructing the line of events from early thyroid hyperplasia to MNG we will argue the predominant neoplastic character of nodular structures, the nature of known somatic mutations, and the importance of mutagenesis. Furthermore, we outline direct and indirect consequences of these somatic mutations for thyroid pathophysiology and summarize information concerning a possible genetic background of euthyroid goiter.

Finally, we discuss uncertainties and open questions in differential diagnosis and therapy of euthyroid and toxic MNG.
Structure–function analysis of yeast tRNA ligase
Authors: WANG LI KAI , SHUMAN STEWART
Published: May 2005

Trl 1 is an essential 827-amino-acid enzyme that executes the end-healing and end-sealing steps of tRNA splicing in Saccharomyces cerevisiae. Trl1 consists of two catalytic domains—an N-terminal adenylyltransferase/ligase component (amino acids 1–388) and a C-terminal 5′-kinase/cyclic phosphodiesterase component (amino acids 389–827)—that can function in tRNA splicing in vivo when expressed as separate polypeptides. Sedimentation analysis indicates that the ligase and kinase/CPD domains are monomeric proteins that do not form a stable complex in trans. To understand the structural requirements for the RNA ligase component, we performed a mutational analysis of amino acids that are conserved in Trl1 homologs from other fungi. Alanine scanning identified 23 new residues as essential for Trl1-(1–388) activity in vivo. Structure–activity relationships at these positions, and four essential residues defined previously, were clarified by introducing 50 different conservative substitutions. Lethal mutations of Lys114, Glu184, Glu266, and Lys284 abolished Trl1 adenylyltransferase activity in vitro. The essential elements embrace (1) putative equivalents of nucleotidyltransferase motifs I, Ia, III, IV, and V found in DNA ligases, T4 RNA ligase 2, and mRNA capping enzymes; (2) an N-terminal segment shared with the T4 RNA ligase 1 subfamily only; and (3) a constellation of conserved residues specific to fungal tRNA splicing enzymes. We identify yeastlike tRNA ligases in the proteomes of Leishmania and Trypanosoma. These findings recommend tRNA ligase as a target for antifungal and antiprotozoal drug discovery.
In vitro RNA random pools are not structurally diverse: A computational analysis
Authors: GEVERTZ JANA , GAN HIN HARK , SCHLICK TAMAR
Published: May 2005

In vitro selection of functional RNAs from large random sequence pools has led to the identification of many ligand-binding and catalytic RNAs. However, the structural diversity in random pools is not well understood. Such an understanding is a prerequisite for designing sequence pools to increase the probability of finding complex functional RNA by in vitro selection techniques. Toward this goal, we have generated by computer five random pools of RNA sequences of length up to 100 nt to mimic experiments and characterized the distribution of associated secondary structural motifs using sets of possible RNA tree structures derived from graph theory techniques. Our results show that such random pools heavily favor simple topological structures: For example, linear stem–loop and low-branching motifs are favored rather than complex structures with high-order junctions, as confirmed by known aptamers. Moreover, we quantify the rise of structural complexity with sequence length and report the dominant class of tree motifs (characterized by vertex number) for each pool. These analyses show not only that random pools do not lead to a uniform distribution of possible RNA secondary topologies; they point to avenues for designing pools with specific simple and complex structures in equal abundance in the goal of broadening the range of functional RNAs discovered by in vitro selection. Specifically, the optimal RNA sequence pool length to identify a structure with x stems is 20x.
Stable-Isotope Dilution Liquid Chromatography–Electrospray Injection Tandem Mass Spectrometry Method for Fast, Selective Measurement of S-Adenosylmethionine and S-Adenosylhomocysteine in Plasma
Authors: Gellekink Henkjan , van Oppenraaij-Emmerzaal Dinny , van Rooij Arno , Struys Eduard A , den Heijer Martin , Blom Henk J
Published: May 2005

Background: It has been postulated that changes in S-adenosylhomocysteine (AdoHcy), a potent inhibitor of transmethylation, provide a mechanism by which increased homocysteine causes its detrimental effects. We aimed to develop a rapid and sensitive method to measure AdoHcy and its precursor S-adenosylmethionine (AdoMet).

Methods: We used stable-isotope dilution liquid chromatography–electrospray injection tandem mass spectrometry (LC-ESI-MS/MS) to measure AdoMet and AdoHcy in plasma. Acetic acid was added to prevent AdoMet degradation. Solid-phase extraction (SPE) columns containing phenylboronic acid were used to bind AdoMet, AdoHcy, and their internal standards and for sample cleanup. An HPLC C18 column directly coupled to the LC-MS/MS was used for separation and detection.

Results: In plasma samples, the interassay CVs for AdoMet and AdoHcy were 3.9% and 8.3%, and the intraassay CVs were 4.2% and 6.7%, respectively. Mean recoveries were 94.5% for AdoMet and 96.8% for AdoHcy. The quantification limits were 2.0 and 1.0 nmol/L for AdoMet and AdoHcy, respectively. Immediate acidification of the plasma samples with acetic acid prevented the observed AdoMet degradation. In a group of controls (mean plasma total Hcy, 11.2 μmol/L), plasma AdoMet and AdoHcy were 94.5 and 12.3 nmol/L, respectively.

Conclusions: Stable-isotope dilution LC-ESI-MS/MS allows sensitive and rapid measurement of AdoMet and AdoHcy. The SPE columns enable simple cleanup, and no metabolite derivatization is needed. The instability of AdoMet is a serious problem and can be prevented easily by immediate acidification of samples.
An emerging role for comprehensive proteome analysis in human pregnancy research
Authors: Shankar Renu , Gude Neil , Cullinane Fiona , Brennecke Shaun , Purcell Anthony W , Moses Eric K
Published: May 2005

Elucidation of underlying cellular and molecular mechanisms is pivotal to the comprehension of biological systems. The successful progression of processes such as pregnancy and parturition depends on the complex interactions between numerous biological molecules especially within the uterine microenvironment. The tissue- and stage-specific expression of these bio-molecules is intricately linked to and modulated by several endogenous and exogenous factors. Malfunctions may manifest as pregnancy disorders such as preterm labour, pre-eclampsia and fetal growth restriction that are major contributors to maternal and perinatal morbidity and mortality. Despite the immense amount of information available, our understanding of several aspects of these physiological processes remains incomplete. This translates into significant difficulties in the timely diagnosis and effective treatment of pregnancy-related complications. However, the emergence of powerful mass spectrometry-based proteomic techniques capable of identifying and characterizing multiple proteins simultaneously has added a new dimension to the field of biomedical research. Application of these high throughput methodologies with more conventional techniques in pregnancy-related research has begun to provide a novel perspective on the biochemical blueprint of pregnancy and its related disorders. Further, by enabling the identification of proteins specific to a disease process, proteomics is likely to contribute, not only to the comprehension of the underlying pathophysiologies, but also to the clinical diagnosis of multifactorial pregnancy disorders. Although the application of this technology to pregnancy research is in its infancy, characterization of the cellular proteome, unearthing of functional networks and the identification of disease biomarkers can be expected to significantly improve maternal healthcare in the future.
Serotoninergic system blockage in the prepubertal rat inhibits spermatogenesis development
Authors: Aragón M A , Ayala M E , Marín M , Avilés A , Damián-Matsumura P , Domínguez R
Published: May 2005

The stimulatory and inhibitory role of serotonin in gonadotropin secretion and in the onset of puberty in the male rat has been previously described, but its role in the establishment of spermatogenesis is not known. The aim of this study was to investigate the effects of serotoninergic inhibition by p-chloroamphetamine (pCA) on the prepubertal-to-adult stage of the rat reproductive system. Hypothalamic serotonin, gonadotropins and sex steroid hormone concentrations were measured, and a histopathological analysis of seminiferous epithelium was carried out on animals treated with pCA from day 30 and killed at 45 or 65 days of age. The pCA treatment significantly reduced the hypothalamic levels of serotonin and its metabolite (5-hydroxyindole-3-acetic acid). This inhibition did not affect the sex steroid hormone or LH concentrations, but rather it induced an increase in FSH concentration in animals of both ages. Spermatogenesis was impaired by pCA treatment. Disruption of seminiferous epithelium and the death of numerous germ cells were observed. Sperm produced by pCA-treated animals was of poor quality and appeared in small quantities. Apparently, serotonin depletion did not affect communication between the hypothalamus and the pituitary, but the FSH increase could have been related to alterations in the seminiferous epithelium effects. The seminiferous epithelium cycle was altered in rats killed at both 45 and 65 days of age, because at each age of killing the distribution of spermatogenesis stages was different. Germ cell apoptosis did not appear to be related to changes in the FSH concentrations, but other factors produced during spermatogenesis could have been involved in this induction. This study showed that serotonin was necessary for the development of normal spermatogenesis in prepubertal rats.
Blood Biochemistry of the Oyster Toadfish
Authors: Mensinger Allen F. , Walsh Patrick J. , Hanlon Roger T.
Published: May 2005

Blood biochemistry parameters were examined in the oyster toadfish Opsanus tau from the late spring through early fall for two consecutive seasons to establish baseline values and evaluate whether any of the parameters could be used as predictors of disease and mortality in this important experimental organism. The blood plasma was analyzed for alkaline phosphatase, gamma-glutamyl transpeptidase, glutamic oxalacetic transaminase, glutamic pyruvic transaminase, blood urea nitrogen (BUN), calcium, cholesterol, triglycerides, uric acid, creatine, bilirubin, total protein, and glucose. Elevated levels of BUN (28.5 ± 4.1 mg/ dL) and depressed levels of cholesterol (83.0 ± 6.3 mg/ dL) were strongly correlated with disease and subsequent death in the oyster toadfish population and thus may serve as useful indices by which to exclude fish from experimental studies.
Postponed air entrainment in dilute suspension coatings
Authors: Yamamura Masato , Miura Hidenobu , Kage Hiroyuki
Published: May 2005

Experimental evidence is provided that the introduction of solid spheres significantly postpones the onset of air entrainment in a particular range of solid concentrations. Spherical poly(methylmethacrylate) particles were dispersed in Newtonian liquids at different weight fractions up to 1 wt %. Despite the monotonic increase in bulk liquid viscosity, the measured onset velocity of air entrainment first increased and then decreased with increasing particle number density. The maximum onset velocity was obtained at a certain particle number density that did not depend on either the particle diameter or the Bond number. A lubrication model was built by newly considering the forced air‐film splitting by particle contacts. The successive consistency between the model prediction and the experimental observation suggests some directions for broadening the applicability of the coating operation to higher surface speeds. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Chemically amplified resists: Chemistry and processes
Authors: Reichmanis E. , Houlihan F. M. , Nalamasu O. , Neenan T. X.
Published: May 2005

Continued advances in mocroelectronic device fabrication are trying the limits of conventional lithographic techniques. In particular, conventional photoresist materials are not appropriate for use with the new technologies that will be necessary for sub‐0.5 μm lithography. One approach to the desing of new resist chemistries involves the concept of chemical amplification, where one photochemical event can lead to a cascade of subsequent reactions that effect a change in solubility of the parent material. The most well‐known chemically amplified resists utilise photchemically generated acid to catalyse crosslinking or deprotection reactions. This paper reviews the acid generator, crosslinking, deprotection and depolymerisation chemistries that have been evaluated for chemical amplification resist processes. Additionaly, process characteristics and resist performance relative to the process environment are addressed.
Modelling of resist performance
Authors: Hartney Mark A.
Published: May 2005

Simulation of lithographic processes uksing novolac/diazonaphthoquinone resists has become widespread over the past 15 years. Several refinements to the original Dill model have been made to account for experimentally observed behavior. Models have also bee extended to cover other resist chemistry, including electron beam resists, chemically amplified resists and surface‐imaging approaches. While these models are not yet mature, useful insight to the chemical mechanisms and processing can be gained through their use.
Traumatic locked‐in syndrome
Authors: Britt Richard H. , Herrick Maie Kaarsoo , Hamilton Richard D.
Published: May 2005

The first case of traumatic locked‐in syndrome caused by direct damage to the brainstem and not by vascular occlusion of the basilar artery is presented. The lesion consisted of cavitary necrosis of the ventral pontomedullary junction and bilateral disruption of the sixth cranial nerves. Other regions of brainstem damage are described and correlated with the patient's neurological deficits. The damage is thought to be due primarily to mechanical stretching occurring during sudden hyperextension injury.
Properties and crystallization kinetics of poly(ether ether ketone)‐co‐poly(ether ether ketone ketone) block copolymers
Authors: Zhang Yun‐He , Liu Qin‐Hua , Niu Ya‐Ming , Zhang Shu‐Ling , Wang Dong , Jiang Zhen‐Hua
Published: May 2005

A series of block copolymers composed of poly(ether ether ketone) (PEEK) and poly(ether ether ketone ketone) (PEEKK) components were prepared from their corresponding oligomers via a nucleophlilic aromatic substitution reaction. Various properties of the copolymers were investigated with differential scanning calorimetry (DSC) and a tensile testing machine. The results show that the copolymers exhibited no phase separation and that the relationship between the glass‐transition temperature (Tg) and the compositions of the copolymers approximately followed the formula Tg = Tg1X1 + Tg2X2, where Tg1 and Tg2 are the glass‐transition‐temperature values of PEEK and PEEKK, respectively, and X1 and X2 are the corresponding molar fractions of the PEEK and PEEKK segments in the copolymers, respectively. These copolymers showed good tensile properties. The crystallization kinetics of the copolymers were studied. The Avrami equation was used to describe the isothermal crystallization process. The nonisothermal crystallization was described by modified Avrami analysis by Jeziorny and by a combination of the Avrami and Ozawa equations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1652–1658, 2005
Urea/NaOH aqueous solution as new solvent of aeromonas gum
Authors: Xu Xiaojuan , Zhang Lina , Zhang Yuying
Published: May 2005

Aeromonas (A) gum, an acidic heteropolysaccharide, formed aggregates easily in NaCl aqueous solution. A novel solvent of the A gum, which can prevent aggregation, was found to be 0.20M urea/0.25M NaOH aqueous solution. The weight‐average molecular weight (Mw), radius of gyration (〈s2〉1/2), and intrinsic viscosity ([η]) of the samples were determined in 0.20M urea/0.25M NaOH aqueous solution at 25°C by light scattering (Mw, 〈s2〉1/2) and viscometry ([η]). The values of Mw, 〈s2〉1/2, and [η] were close to those in 0.20M lithium chloride/dimethylsulfoxide, in which the A gum exists as a semiflexible single chain, implying the same conformation for the A gum in 0.20M urea/0.25M NaOH aqueous solution. The results revealed that 0.20M urea/0.25M NaOH aqueous solution is a good solvent, which effectively avoids the aggregates of the A gum in aqueous solution. Moreover, it can be used to investigate the solution properties and chain conformation of water‐insoluble polysaccharides or the polysaccharides that are easily aggregated in aqueous systems. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1710–1713, 2005
Impact of hexafluoroisopropylidene on the solubility of aromatic‐based polymers in supercritical fluids
Authors: Shen Zhihao , McHugh Mark A. , Smith Dennis W. , Abayasinghe Nilmini K. , Jin Jianyong
Published: May 2005

Three different supercritical fluids (SCF), CO2, dimethyl ether (DME), and propane, are investigated as potential solvents for processing two lactide‐based terpolymers and two perfluorocyclobutyl (PFCB) aryl ether polymers. The repeat unit of the lactide‐based terpolymers consists of a 1:1:1 ratio of L‐lactide, diglycidyl ether of bisphenol A (DGEBA), and, in one case, 4,4′‐hexafluoroisopropylidenediphenol (6F‐Bis‐A) and, in the other case, 4,4′‐isopropylidenediphenol (6H‐Bis‐A). The PFCB‐based polymers are synthesized from 1,1‐bis[4‐[(trifluorovinyl)oxy]phenyl]hexafluoroisopropylidene (6FVE) and from bis(trifluorovinyloxy)biphenyl (BPVE). For both classes of polymer the steric effect of the hexafluoroisopropylidene (6F) group reduces chain–chain interactions, disrupts electronic resonance between adjacent aromatic groups, and improves solubility. The two lactide‐based terpolymers do not dissolve in CO2 or propane, but dissolve in DME. At room temperature the poly(lactide 6F‐BisA DGEBA) terpolymer dissolves at 700 bar lower pressure in DME compared to the poly(lactide 6H‐Bis‐A DGEBA) terpolymer. Although the 6FVE polymer dissolves in all three SCF solvents, pressures in excess of 800 bar are needed to dissolve this polymer in CO2 and propane while 6FVE dissolves in DME at pressure below 150 bar. The other PFCB‐based polymer (BPVE) only dissolves in DME, again at low pressure, although BPVE drops out of solution as the system temperature is raised above ∼40°C, whereas 6FVE remains in solution in DME for temperatures up to 90°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1736–1743, 2005
Highly active Ziegler–Natta catalyst for propylene polymerization
Authors: Abedi S. , Daftari‐Besheli M. , Shafiei S.
Published: May 2005

Polymerization of propylene was carried out by using a MgCl2–EtOH–TiCl4–ID–TEA–ED catalyst system in n‐heptane, where ID (internal donor) was an organic diester, ED (external donor) was a silane compound, and TEA (triethyl aluminum) was the activator. The influences of temperature, pressure, time, hydrogen, and the molar ratios of Al/Ti and ED/Ti on polymer isotacticity and catalyst activity were studied by solubility in boiling n‐heptane and measuring the polymer produced, respectively. The morphology of the polymers was evaluated through scanning electron microscopy and particle size distribution. The rheological properties of the poly(propylene) were determined by the melt flow index. It was found that the catalyst showed good morphology and high activity and also the produced polymers were characterized by high isotacticity and globulelike shapes. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1744–1749, 2005
Detection of possible archaeological pathways in central Mexico through digital processing of remote sensing images
Authors: Argote‐Espino Denisse , Chávez René E.
Published: May 2005

Many spaceborne multispectral images have been developed recently and applied in archaeology as they provide useful data, which can be digitized, manipulated and integrated. Principal component decomposition (PCD), texture segmentation and linear pattern detection through spatial filtering are useful techniques that provide a new way of processing satellite images in addition to traditional techniques. Such methods may supply more accurate information of an area, in particular a region of archaeological interest. In this paper we applied a new alternative method based on the techniques mentioned above to an important area of central Mexico. The region of study is located to the southwest of Las Cruces Range between the Mexico Basin and the Toluca Valley. Processing a multispectral image from that area, it was possible to detect possible communication corridors, which provided cultural and commercial linking to the ancient settlers of both adjacent basins. This information is very important for understanding the way these people interacted in the past and the commercial importance that could exist between them. Copyright © 2005 John Wiley & Sons, Ltd.
A numerical evaluation of SAR distribution and temperature changes around a metallic plate in the head of a RF exposed worker
Authors: McIntosh Robert L. , Anderson Vitas , McKenzie Raymond J.
Published: May 2005

The 1998 International Commission for Non‐Ionising Radiation (ICNIRP) Guidelines for human exposure to radiofrequency (RF) fields contain a recommendation to assess the potential impact of metallic implants in workers exposed up to the allowable occupational field limits. This study provides an example of how numerical electromagnetic (EM) and thermal modelling can be used to determine whether scattered RF fields around metallic implants in workers exposed to allowable occupational ambient field limits will comply with the recommendations of relevant standards and guidelines. A case study is performed for plane wave exposures of a 50 mm diameter titanium cranioplasty plate, implanted around 5–6 mm under the surface of the forehead. The level of exposures was set to the ambient power flux density limits for occupational exposures specified in the 1998 ICNIRP guidelines and the current 1999 IEEE C95.1 standard over the frequency range 100–3000 MHz. Two distinct peak responses were observed. There was a resonant response for the whole implant at 200–300 MHz where the maximum dimension of the implant is around a third of the wavelength of the RF exposure. This, however, resulted in relatively low peak specific energy absorption rate (SAR) levels around the implant at the exposure limits. Between 2100–2800 MHz, a second SAR concentrating mechanism of constructive interference of the wave reflected back and forth between the air‐scalp interface and the scalp‐plate interface resulted in higher peak SARs that were within the allowable limits for the ICNIRP exposures, but not for the IEEE C95.1 exposures. Moreover, the IEEE peak SAR limits were also exceeded, to a lesser degree, even when the implant was not present. However, thermal modelling indicated that the peak SAR concentrations around the implant did not result in any peak temperature rise above 1 °C for occupational exposures recommended in the ICNIRP guidelines, and hence would not pose any significant health risk. Bioelectromagnetics 26:377–388, 2005. © 2005 Wiley‐Liss, Inc.
The effect of buffers and chelators on the reaction of luminol with Fenton's reagent near neutral pH
Authors: Bottu G.
Published: May 2005

The chemiluminescence of the system luminol +Fe2+ + H2O2 was measured in aqueous buffer at pH 7.2. In veronal (5,5‐diethybarbiturate) buffer, the luminescence is strongly quenched by ethanol and mannitol, but only weakly by t‐butanol, benzoate and superoxide dismutase (SOD); complexing Fe2+ with 1,10‐phenanthroline or 2,2′‐dipyridyl causes a decrease of light production that can be partially obviated by the simultaneous addition of SOD. In phosphate buffer, the luminescence is higher than in veronal and it is efficiently quenched by all four OH · quenchers and by SOD. In Tris buffer, no light production is observed as long as the Fe2+ is not complexed. When Fe2+ is complexed by pyrophosphate or phytate, there is a strong chemiluminescence in all three buffers, which is quenched by all four OH · quenchers and by SOD. When Fe2+ is complexed by EDTA or DTPA, very little luminescence is observed. The luminol analogue phthalhydrazide, which was suggested by Merényi and Lind as a reliable OH · detector, can replace luminol only in phosphate buffer, and thus turns out to be very specific indeed for free OH ·.
Detection of substances with alcoholic or phenolic hydroxyl groups by generation of hydrogen peroxide with imidazole and peroxyoxalate chemiluminescence
Authors: Nozaki Osamu , Iwaeda Toshinao , Kato Yoshio
Published: May 2005

On‐line detection of substances with an alcoholic or phenolic hydroxyl group using imidazole and peroxyoxalate chemiluminescence was investigated qualitatively using a flow‐injection method. The substances tested included six polyphenols, five monophenols and six sugars. After incubation at 80°C with an imidazole buffer (pH 9.5) the substances were detected by peroxyoxalate chemiluminescence. The polyphenols tested (e.g., pyrogallol, purpurogallin, and dopamine) showed the strongest light emission. The sugars with hydroxyl groups (e.g., fructose and lactose) and the monophenols (e.g., phenol, serotonin, and β‐estradiol) produced only a weak light emission. Reaction of hydroxyl compounds and imidazole generated hydrogen peroxide. Imidazole served two roles, it catalysed the reaction with the hydroxyl compound and initiated peroxyoxalate chemiluminescence on‐line. A novel reactor formed by packing glass beads into a flow cell (Teflon) of a chemiluminometer improved the sensitivity of light detection.
Chemiluminescence sandwich enzyme immunoassay for determination of human granulocyte colony stimulating factor (G‐CSF)
Authors: Aoyagi Shigeo , Arasawa Kazue , Matsuyuki Akira , Kamatchi Shin‐ichi , Fukushima Masafumi , Ohsawa Nakaaki
Published: May 2005

A chemiluminescence sandwich enzyme immunoassay, using a glucose oxidase (GO) label, was developed for detecting attomole amounts of human granulocyte colony stimulating factor (G‐CSF). Purified goat F(ab′)2 immobilized on a bead and purified goat Fab′ labelled with GO were selected in combination with a chemiluminescent detection system comprising luminol and ferricyanide. The detection limits for G‐CSF were 4amol/assay (1 pg/mL) in buffer solution and 10 amol/assay (2.5 pg/mL) in human serum. Coefficients of variation within assay and between assay ranged from 5.5% to 7.8% and from 3.4% to 16.0%, respectively. The G‐CSF content of serum from normal healthy individuals was measurable using this method. G‐CSF in 24 normal human sera showed a mean value of 19.3 pg/mL and ranged from 3.6 to 83.0 pg/mL.
Flow injection analysis of riboflavin with chemiluminescence detection using a N‐halo compounds–luminol system
Authors: Safavi A. , Karimi M. A. , Nezhad M. R. Hormozi
Published: May 2005

A chemiluminescent method for the determination of riboflavin is described. The method is based on the chemiluminescence (CL) generated during the oxidation of luminol by N‐bromosuccinimide (NBS) and N‐chlorosuccinimide (NCS) in alkaline medium. It was found that riboflavin could greatly enhance this CL intensity when present in the luminol solution. Based on this observation, a new flow‐injection CL method for the determination of riboflavin is proposed in this paper. The detection limits were 7.5 ng[sol ]mL and 3.5 ng[sol ]mL of riboflavin for the NBS– and NCS–luminol CL systems, respectively. The relative CL intensity was linear, with riboflavin concentration in the range 19–600 ng[sol ]mL and 600–2000 ng[sol ]mL for the NBS–luminol CL system, and 12–200 ng[sol ]mL and 200–2000 ng[sol ]mL for the NCS–luminol CL system. The results obtained for the assay of pharmaceutical preparations compared well with those obtained by the official method and demonstrated good accuracy and precision. Copyright © 2005 John Wiley & Sons, Ltd.
A new on‐line micellar‐enhanced photochemically‐induced fluorescence method for determination of phenylurea herbicide residues in water
Authors: Irace‐Guigand Sandrine , Leverend Emilie , Seye Mame Diabou Gaye , Aaron Jean Jacques
Published: May 2005

A new flow injection analysis micellar‐enhanced photochemically induced fluorescence (FIA–MEPIF) method was developed for the determination of four phenylurea herbicides, including isoproturon, néburon, linuron and diuron. On‐line photoconversion under UV irradiation of these herbicides into strongly fluorescent photoproducts was performed in buffered aqueous solutions and in the presence of surfactants [sodium dodecyl sulphate (SDS) or cetyl trimethyl ammonium chloride (CTAC)] at micellar concentrations. The MEPIF and FIA parameters were optimized. The analytical figures of merit for the determination of the four herbicides were satisfactory, with concentration linear dynamic ranges over about one to two orders of magnitude, detection limits of 0.33–0.92 mg[sol ]L and relative standard deviations of 1.3–11%, according to the compound. Application to the analysis of fortified tap water samples yielded good recovery values (91–103%, according to the herbicide). Our results show that the on‐line MEPIF–FIA method is simple, versatile, sensitive and can be easily applied to quantify pollutant residues in multiresidue systems. Copyright © 2005 John Wiley & Sons, Ltd.
Study on the effect of thiamine on the metabolism of yeast by intrinsic fluorescence
Authors: Wang Jun , Cai Ruxiu , Xu Jing , Liu Zhihong
Published: May 2005

Thiamine in living human bodies exists mainly as diphosphate, which works as a co‐enzyme of the sugar metabolism system (active vitamin B1). Thiamine deficiency brings many clinically significant problems, such as dysphoria, quadriplegia and dyspepsia. Intrinsic fluorescence has an advantage over the extrinsic fluorescence of an unperturbed environment during investigation, especially in complex systems such as biological cells and tissues. Cellular fluorescence provides a sensitive index of the functional state of a living cell (1). Different amounts of thiamine were added to culture medium and the fluorescence of tryptophan and NADH from yeast was determined. When the thiamine concentration was greater than 0–0.16 µg[sol ]mL, the intensity of tryptophan fluorescence increased linearly, whereas the NADH fluorescence decreased. When the thiamine concentration was above 0.24 µg[sol ]mL, the fluorescence of tryptophan and NADH was almost unchanged. We concluded that low thiamine concentration in culture medium had a large effect on the growth of Saccharomyces cerevisiae and possible reasons are discussed. Copyright © 2005 John Wiley & Sons, Ltd.