bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, characterization, and degradation of poly(anhydride‐co‐amide)s and their blends with polylactide
Authors: Zhang Zhi‐Qin , Su Xin‐Mei , He Han‐Ping , Qu Fan‐Qi
Published: July 2004

In attempt to improve the properties of polyanhydrides based on aliphatic anhydrides, we synthesized novel polyanhydrides containing amide groups in the main chains. In this work, N,N′‐bis(L‐alanine)‐sebacoylamide (BSAM) was prepared from natural amino acid and sebacic acid (SA) and characterized by IR and 1H NMR. In addition, polymers of PBSAM, P[1,6‐bis(P‐carboxyphenoxy) hexane (CPH)‐BSAM], and P(CPH‐SA), blends of P(CPH‐SA)/polylactide (PLA), P(CPH‐BSAM)/PLA were also prepared and characterized by IR, gel permeation chromatography, and differential scanning calorimetry. The hydrolytic degradation of polyanhydrides and their blends with PLA (number‐average molecular weight = 2.90 × 105) was evaluated in 0.1 M phosphate buffer pH 7.4 at 37 °C. The results indicate that the existence of amide, aromatic, and ester bonds in the main chain of polymers slows down the degradation rate, and the tendency becomes clearer with the increasing amount of them, and the copolymers and their blends with PLA possess excellent physical and mechanical properties. These can make them more widely used in drug delivery and nerve regeneration. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4311–4317, 2004
Direct synthesis of linear low‐density polyethylene of ethylene/1‐hexene from ethylene with a tandem catalytic system in a single reactor
Authors: Alobaidi Fahad , Ye Zhibin , Zhu Shiping
Published: July 2004

Tandem catalysis offers a promising synthetic route to the production of linear low‐density polyethylene. This article reports the use of homogeneous tandem catalytic systems for the synthesis of ethylene/1‐hexene copolymers from ethylene stock as the sole monomer. The reported catalytic systems employ the tandem action between an ethylene trimerization catalyst, (η5‐C5H4CMe2C6H5)TiCl3 (1)/modified methylaluminoxane (MMAO), and a copolymerization metallocene catalyst, [(η5‐C5Me4)SiMe2(tBuN)]TiCl2 (2)/MMAO or rac‐Me2Si(2‐MeBenz[e]Ind)2ZrCl2 (3)/MMAO. During the reaction, 1/MMAO in situ generates 1‐hexene with high activity and high selectivity, and simultaneously 2/MMAO or 3/MMAO copolymerizes ethylene with the produced 1‐hexene to generate butyl‐branched polyethylene. We have demonstrated that, by the simple manipulation of the catalyst molar ratio and polymerization conditions, a series of branched polyethylenes with melting temperatures of 60–128 °C, crystallinities of 5.4–53%, and hexene percentages of 0.3–14.2 can be efficiently produced. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4327–4336, 2004
Synthesis and chirooptical properties of optically active poly(ester imide)s based on axially asymmetric 1,1′‐binaphthyls
Authors: Song Naiheng , Qi Wei , Qiu Xuepeng , Gao Lianxun , Ding Mengxian
Published: July 2004

A series of optically active poly(ester imide)s (PEsI's) has been synthesized by the polycondensation reactions of new axially asymmetric dianhydrides, that is, (R)‐2,2′‐bis(3,4‐dicarboxybenzoyloxy)‐1,1′‐binaphthyl dianhydride and (S)‐2,2′‐bis(3,4‐dicarboxybenzoyloxy)‐1,1′‐binaphthyl dianhydride, and various diamines with aromatic, semiaromatic, and aliphatic structures. The polymers have inherent viscosities of 0.45–0.70 dL/g, very good solubility in common organic solvents, glass‐transition temperatures of 124–290 °C, and good thermal stability. Wide‐angle X‐ray crystallography of these polymers shows no crystal diffraction. In comparison with model compounds, an enhanced optical rotatory power has been observed for the repeat unit of optically active PEsI's based on aromatic diamines, and it has been attributed to a collaborative asymmetric perturbation of chiral 1,1′‐binaphthyls along the rigid backbones. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4318–4326, 2004
Structural study of the influence of partially crystalline poly(ethylene butene) random copolymers on paraffin crystallization in dilute solutions
Authors: Radulescu Aurel , Schwahn Dietmar , Monkenbusch Michael , Fetters Lewis J. , Richter Dieter
Published: July 2004

Random crystalline–amorphous copolymers containing ethylene and butene segments, yielded from dilute‐solution, and self‐assembled to one‐dimensional, needle‐shaped aggregates, can modify wax crystal structures through the cocrystallization of the copolymer and wax molecules into hairy platelets. These copolymers show selectivity in their wax crystal modification capacities that depends on the ethylene content of the backbone. Thus, it has been qualitatively established that a copolymer containing larger crystallizable polyethylene sections [poly(ethylene butene) with 7.5 ethyl branches per 100 backbone carbons (PEB‐7.5)] is very efficient for longer wax molecules (C36), whereas for shorter waxes (C24), its efficacy diminishes. Here we present a quantitative evaluation of the small‐angle neutron scattering results obtained in a complex study of the self‐assembling behavior of PEB‐7.5 and paraffin waxes (C24 and C36) in decane and of cocrystallization for different polymer–paraffin combinations and solution conditions. The richness of the morphologies was evaluated with a contrast variation technique and the application of structural models. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3113–3132, 2004
Dornase alpha and exhaled NO in cystic fibrosis
Authors: Grasemann Hartmut , Lax Hildegard , Treseler Jennifer W. , Colin Andrew A.
Published: July 2004

Nitric oxide (NO) that is produced within the airways can be measured in the exhaled air. Concentrations of exhaled NO (FENO) are decreased in cystic fibrosis (CF) and, in cross sectional studies, have been shown to be even lower in patients with more advanced pulmonary disease. This may result from retention and metabolisation of NO within viscous airway secretions. Treatment with recombinant human DNase I (dornase alpha) modifies the rheological properties of airway secretions and thereby improves pulmonary function even in young and apparently healthy patients with CF. We studied FENO and pulmonary function in children with CF with little clinical evidence of lung morbidity in a two‐year randomized double‐blind placebo‐controlled study with nebulized dornase alpha. Mean age at enrollment was 8 years (range 6 to 11 years), mean forced vital capacity (FVC) was 112% (range 86 to 133%), and mean forced expiratory volume in one second (FEV1)was 109% (range 88 to 128%) of predicted values. In five of six (83%) of the dornase alpha treated patients, FENO changed in parallel to changes in pulmonary function tests while no such correlation was observed in any of the eight patients receiving placebo. This difference between treatment groups was statistically significant for both FVC (P = 0.026, Wilcoxon‐test) and FEV1 (P = 0.042). These data suggest that FENO may serve as a surrogate measure for evaluating the effectiveness of interventions that affect airway clearance in CF. Pediatr Pulmonol. © 2004 Wiley‐Liss, Inc.
Infant immunization and the occurrence of atopic disease in Dutch and German children: A nested case‐control study
Authors: Mommers M. , Weishoff‐Houben M. , Swaen G.M.H. , Creemers H. , Freund H. , Dott W. , van Schayck C.P.
Published: July 2004

Our goal was to assess the role of early childhood vaccination in the occurrence of respiratory symptoms and allergic sensitization in 7–8‐year‐old Dutch and German children. A nested case‐control study was conducted among children participating in a large longitudinal study on respiratory health, to study the relationship between vaccination (bacille Calmette‐Guérin (BCG), pertussis, measles/mumps, rubella, and Haemophilus influenza type b (Hib)) and respiratory symptoms and allergic sensitization. Parents of 510 7–8‐year‐old children with respiratory complaints and an equal number of randomly selected children without respiratory complaints were asked to complete a questionnaire. Blood samples were collected for specific serum IgE analysis. Vaccination status was assessed through the records of the participating Municipal Health Services. No association between vaccination against pertussis, measles, rubella, or Hib and respiratory symptoms or allergic sensitization was found. For sensitization against house dust mite, BCG vaccination resulted in an increased risk (OR, 2.28; 95% CI, 1.05–4.96). Birth order was inversely associated with allergic sensitization, but was not related to respiratory symptoms. We found an association between BCG vaccination and the subsequent risk for sensitization against house dust mite. No evidence was found for an association between vaccination and respiratory symptoms. Earlier reports of an association of birth order with atopic disease were supported by the results of the present study. Pediatr Pulmonol. 2004; 38:329–334. © 2004 Wiley‐Liss, Inc.
Longitudinal pulmonary status of cystic fibrosis children with meconium ileus
Authors: Li Zhanhai , Lai HuiChuan J. , Kosorok Michael R. , Laxova Anita , Rock Michael J. , Splaingard Mark L. , Farrell Philip M.
Published: July 2004

Although meconium ileus (MI) is the earliest manifestation of cystic fibrosis (CF), and is associated with poorer growth, the longitudinal pulmonary progression of CF children with MI is not clear. To test the hypothesis that MI is associated with worse pulmonary outcomes, we prospectively compared from diagnosis to 12 years of age 32 CF children with MI to 50 CF children without MI who were diagnosed during early infancy through neonatal screening. Pulmonary outcome measures included respiratory symptoms, respiratory infections, pathogens, antibiotic usage, hospitalizations, quantitative chest radiology, spirometry, and lung volume determinations. Obstructive lung disease was defined as percent predicted spirometry values below the lower limits of normal. Longitudinal analyses revealed no significant differences in cough, wheezing, respiratory infections, prevalence of and median times to acquisition of Pseudomonas aeruginosa or Staphylococcus aureus, antibiotic usage, and chest radiograph scores between the two groups. However, MI children showed significantly worse forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC), forced expiratory flow between 25–75% of FVC (FEF25–75), % predicted FEV1, % predicted FEF25–75, and total lung capacity (TLC). These differences were particularly apparent beginning at age 8–10 years. MI children also had higher rates of and shorter median times to obstructive lung disease. Subgroup analyses showed MI children treated surgically and those treated medically had similar pulmonary outcomes. In conclusion, MI children have worse lung function and more obstructive lung disease than those without MI. Such abnormalities are accompanied by reduced lung volume. MI is a distinct CF phenotype with more severe pulmonary dysfunction. Pediatr Pulmonol. 2004; 38:277–284. © 2004 Wiley‐Liss, Inc.
Treatment with tobramycin solution for inhalation reduces hospitalizations in young CF subjects with mild lung disease
Authors: Murphy Timothy D. , Anbar Ran D. , Lester Lucille A. , Nasr Samya Z. , Nickerson Bruce , VanDevanter Donald R. , Colin Andrew A.
Published: July 2004

Our objective was to study the effect of tobramycin solution for inhalation (TSI; TOBI®, Chiron Corp.) on lung function decline rate in 400 young persons with cystic fibrosis (CF) and mild lung disease. Effects on hospitalization, antibiotic use, school days missed, and nutritional status also were determined. This was an open‐label, randomized (stratified by sex and age group, i.e., 6–10 and 11–15 years), parallel‐group, multicenter study. Routine subject management (control group) was compared to routine management plus 28 days of twice‐daily TSI inhalation, followed by 28 days off the drug (TSI group) for 56 weeks. Primary efficacy endpoints included rate of lung function decline (as measured by forced expiratory volume in 1 sec; FEV1), hospitalization, and concomitant antibiotic use. Safety was assessed by analysis of treatment‐emergent adverse events. Only 184 of 400 planned subjects were recruited and randomized (93 to the TSI group, and 91 to the control group). Enrollment was ended after 2 years because of difficult recruitment. An interim safety review showed a 2.42‐fold risk of respiratory hospitalization for control group subjects (P = 0.020), and the study was terminated. Sixty‐three subjects (34.2%) completed the entire study (30 in the TSI group, or 32.3%; and 33 in the control group, or 36.3%). Significantly fewer TSI subjects were hospitalized for worsening of respiratory symptoms (11.0% vs. 25.6%; P = 0.011), and fewer TSI subjects were hospitalized overall (16.5% vs. 27.8%; P = 0.065). Fewer TSI subjects received antibiotics other than the study drug (78.0% vs. 95.6%), and significantly fewer received oral antibiotics (76.9% vs. 91.1%; P = 0.009). No other safety or adverse event differences were observed. In conclusion, significant reductions in respiratory hospitalizations, concomitant antibiotic use, and a trend towards improvement in percent predicted forced expiratory flow (FEF25–75) provide evidence of a clinical benefit of TSI use in young persons with CF and mild lung disease. An effect on lung function decline rate could not be evaluated as planned, due to inadequate enrollment and early study termination. Pediatr Pulmonol. 2004; 38:314–320. © 2004 Wiley‐Liss, Inc.
Pulmonary lymphangiectasia: Diagnosis and clinical course
Authors: Esther Charles R. , Barker Pierre M.
Published: July 2004

Pulmonary lymphangiectasia (PL) is a rare disease characterized by dilation of the normal lung lymphatics. The disease was previously associated with a poor prognosis. However, several recent case reports and case studies indicate that survival is possible in the severe neonatal form of PL, and the prognosis is good for infants who present after the neonatal period. In this report, we describe the etiology, clinical presentation, diagnosis, management, and outcome of PL. A revised classification of PL is proposed, based on the current state of knowledge of its etiology and presentation. Pediatr Pulmonol. 2004; 38:308–313. © 2004 Wiley‐Liss, Inc.
Measurement of inspiratory flow in children with acute asthma
Authors: Bentur Lea , Mansour Yasser , Hamzani Yaniv , Beck Raphael , Elias Nael , Amirav Israel
Published: July 2004

Dry‐powder inhalers (DPIs) have been proposed for treatment of acute asthma. Different DPIs vary in their inspiratory resistance and have different recommended optimal peak inspiratory flows (PIFs). Reduced PIF during acute asthma may result in inadequate drug delivery to the lungs. Our aim was to measure the inspiratory flow in relation to inspiratory resistance during acute asthma in children presenting to the emergency room. School‐age (range, 6–18 years) children were referred to the emergency room for acute asthma. PIF measurements were performed by In‐Check Dial™ device with simulated airflow resistances equivalent to Turbuhaler®, Diskus,® and free flow. Percent change in PIF between remission and acute asthma (%Δ) was correlated with percent change in clinical score (CS) and percent change in spirometry in children <9 and >9 years old. Thirty‐three children (21 males) participated. PIF with simulated Turbuhaler resistance was significantly lower than with simulated Diskus resistance in both acute and remission states (P < 0.0001). PIF with simulated Turbuhaler resistance increased from 62.1 ± 15.3 (acute) to 74.4 ± 16.5 l/min (remission, P < 0.0001), while with Diskus it rose from 72.6 ± 20.5 to 91.1 ± 18.9 l/min (P < 0.0001). Turbuhaler %Δ PIF correlated with %Δ FEV1 (P = 0.01) and with %Δ CS (P = 0.0001). A lesser degree of correlation was observed while using Diskus resistance and in children above 9 years old. During acute asthmatic attacks, PIF is reduced; this reduction is particularly prominent in young children who use a high‐resistance device. However, the PIF generated is generally within the values considered compatible with adequate lung deposition with both Diskus and Turbuhaler. Pediatr Pulmonol. 2004; 38:304–307. © 2004 Wiley‐Liss, Inc.
Pediatric bronchiectasis: Correlation of HRCT, ventilation and perfusion scintigraphy, and pulmonary function testing
Authors: Pifferi Massimo , Caramella Davide , Bulleri Alessandra , Baldi Simonetta , Peroni Diego , Pietrobelli Angelo , Boner Attilio L.
Published: July 2004

Bronchiectasis in children, although occurring with diminished frequency, continues as a major challenge for the pediatric pulmonologist. The method of choice for the diagnosis of the condition is high‐resolution computed tomography (HRCT). The aim of the present study was to correlate the relationship(s) of HRCT, lung function, ventilation lung scintigraphy (VLS), and perfusion lung scintigraphy (PLS) in children with bronchiectasis. Sixteen children ranging in age from 4–18 years with clinical and chest X‐ray evidence of bronchiectasis were enrolled in the study. The degree of bronchiectasis was assessed by HRCT scores, decrease in attenuation on expiratory scans, VLS, and PLS. HRCT scores for bronchiectasis and decreased lung attenuation showed a strong correlation with PLS (ρ = 0.82; P < 0.001) and with VLS (ρ = 0.72; P < 0.01). There was a moderate negative correlation between FEV1 and HRCT bronchiectasis scores (ρ = −0.53; P = 0.02), decreased lung attenuation score (ρ = −0.64; P = 0.007), and atelectasis score (ρ = −0.54; P = 0.03). In conclusion, HRCT provides a complete and precise assessment of children with bronchiectasis. Ventilation/perfusion scans and lung functions are additive tools to understand the complexity of the disease process and to improve diagnosis and therapeutic strategies. Pediatr Pulmonol. 2004; 38:298–303. © 2004 Wiley‐Liss, Inc.
Theoretical AM1 studies of inclusion complexes of heptakis(2‐O‐hydroxypropyl)‐β‐cyclodextrins with alkylated phenols
Authors: Huang Ming‐Ju , Yi Manyin
Published: August 2004

Semiempirical Austin model I (AM1) calculations have been performed on a family of inclusion complexes of heptakis(2‐O‐hydroxypropyl)‐β‐cyclodextrin isomers derived from the 2‐hydroxyl position (2HPβCD) and from the 6‐hydroxyl position (6HPβCD) with alkylated phenol derivatives. From the stabilization energies and hydrogen bonding studies of the inclusion complexes of 2HPβCD and 6HPβCD with substituted phenols in head‐first and tail‐first positions, we found that the main driving forces for the formation of the inclusion complexes are from the van der Waals interactions. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Continuous‐flow sample introduction for field desorption/ionization mass spectrometry
Authors: Schaub Tanner M. , Linden H. Bernhard , Hendrickson Christopher L. , Marshall Alan G.
Published: July 2004

We introduce continuous‐flow field desorption (FD) for improved spectral quality, higher sample throughput, and simpler interface to sample handlers and chromatographic equipment. A recently developed commercial FD probe with integral fused‐silica capillary allows sample dosing in situ, without probe removal and reinsertion. A stable FD‐generated ion current can be sustained for longer than an hour by continuous deposition of analyte solution on the FD emitter heated and at high voltage. Continuous‐flow FD allows ensemble averaging of up to 100 Fourier transform ion cyclotron resonance (FT‐ICR) mass spectra, in contrast to the traditional emitter dosing technique. Continuous‐flow FD is amenable to interface with liquid chromatography (LC) and/or automated sample injectors. Copyright © 2004 John Wiley & Sons, Ltd.
Flow‐rate characterization of microfabricated polymer microspray emitters
Authors: Lion Niels , Gellon Jean‐Olivier , Girault Hubert H.
Published: July 2004

Microfabricated polymer microspray emitters are characterized in terms of applicable flow rates, temporal and spectral signal‐to‐noise ratios (SNRs), and solution composition. First, microspray emitters can be operated with 50% methanol/49% water/1% acetic acid from 250 nL/min up to 7 μL/min, with better SNRs above 1 μL/min. Interestingly, even at the lowest flow rates tested, they compare well with nanospray capillaries in terms of mass spectral performances. Secondly, they can be operated with acetonitrile from 10 up to 99% (v/v), with flow rates from 250 nL/min up to 4 μL/min. Even if the mass spectral performances (especially the spectral SNRs) vary with the acetonitrile content, this study validates such microfabricated microspray emitters as interfaces between liquid‐phase separations and electrospray mass spectrometers. Copyright © 2004 John Wiley & Sons, Ltd.
Trace level quantification of deuterated 17β‐estradiol and estrone in ovariectomized mouse plasma and brain using liquid chromatography/tandem mass spectrometry following dansylation reaction
Authors: Xia Yuan‐Qing , Chang Steve W. , Patel Shefali , Bakhtiar Ray , Karanam Bindhu , Evans David C.
Published: July 2004

A sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method coupled with dansylation was developed for the simultaneous quantification of exogenously administered deuterated 17β‐estradiol‐d4 (E2‐d4) and its metabolite, estrone‐d4 (E1‐d4), in mouse plasma and brain homogenates. The dansylation reaction was simple, fast, and sensitive, and a lower limit of quantification of 50 pg/mL was achieved by using 50 μL of mouse plasma. Interference from endogenous 17β‐estradiol and estrone in plasma and brain samples was minimized by the use of deuterated‐E2 as well by utilizing ovariectomized (OVX) mice. The recovery of dansylated derivative exceeded 83% and the reaction was completed within approximately 3 min. The intra‐ and inter‐day assay precision were better than 12.9% and assay accuracy ranged between 92–104% for E1‐d4 and E2‐d4 in plasma, respectively. The absorption of E2‐d4 at both 1 and 3 mg/kg P.O. was rapid, reaching peak plasma concentrations (Cmax) at 5 min post‐dose that was the earliest time point obtained, and were 1.1 and 13.8 ng/mL, respectively; the Cmax values for the estrone metabolite, E1‐d4, were 1.1 and 43.2 ng/mL, respectively. The area‐under‐the‐plasma‐time curve (AUC0‐2h) values were determined to be 0.65 and 2.90 ng · h/mL for E2‐d4 and 0.77 and 6.74 ng · h/mL for E1‐d4, respectively, at 1 and 3 mg/kg. The mean brain‐to‐plasma ratio for E1‐d4 and E2‐d4 after P.O. administration of E2‐d4 to the OVX mice at 1 and 3 mg/kg indicated that both E1‐d4 and E2‐d4 were present in the brain as well as in the circulation. Copyright © 2004 John Wiley & Sons, Ltd.
Determination of alkanolamines in cattails (Typha latifolia) utilizing electrospray ionization with selected reaction monitoring and ion‐exchange chromatography
Authors: Peru Kerry M. , Headley John V. , Doucette William J.
Published: July 2004

Selected reaction monitoring (SRM) with electrospray ionization was used as a specific detection technique for the analysis of alkanolamines in plant tissue extracts. Ion‐exchange chromatography was used as the method of separation. Quantification was based on monitoring the loss of either H2O or 2(H2O) from the protonated molecule [M+H]+. The method provided increased selectivity for all analytes and better detection limits for three of the six analytes investigated compared with an earlier method using selected ion monitoring with liquid chromatography. Instrumental detection limits ranged from 6–300 pg injected for monoethanolamine (MEA), monoisopropanolamine (MIPA), diethanolamine (DEA), methyldiethanolamine (MDEA), diisopropanolamine (DIPA), and triethanolamine (TEA). Method robustness and selectivity were demonstrated by the determination of DIPA and a known transformation product MIPA in over 35 plant extract samples derived from a laboratory study of plant uptake mechanisms. Copyright © 2004 John Wiley & Sons, Ltd.
Formation of iminium ions by fragmentation of a2 ions
Authors: Harrison Alex G. , Young Alex B. , Schnoelzer Martina , Paizs Béla
Published: July 2004

Tandem mass spectrometric experiments have been carried out on the protonated amides H‐Gly‐Ala‐NH2, H‐Ala‐Gly‐NH2, H‐Ala‐Val‐NH2, H‐Val‐Ala‐pNA, H‐Leu‐Phe‐NH2, H‐Phe‐Leu‐NH2, H‐Phe‐Tyr‐NH2 and H‐Tyr‐Phe‐NH2 with particular emphasis on the fragmentation of the isomeric a2 ions derived therefrom. Primary fragmentation reactions of the protonated amides involve formation of the y1″ and b2 ions with further fragmentation of the b2 ion to form the a2 ion which fragments to form iminium ions. Collision‐induced dissociation studies of the mass‐selected a2 ions were carried out. For the Gly‐Ala, Ala‐Gly and Val‐Ala a2 ions, weak signals were observed corresponding to loss of CO from the a2 ion. With the exception of the Gly‐Ala, Ala‐Gly and Val‐Ala a2 ions, both possible iminium ions (a1 and the internal iminium ion) are observed with the most abundant being that formed by proton attachment to the imine of higher proton affinity. The results provide strong support for the recently proposed (El Aribi et al. J. Am. Chem. Soc. 2003; 125: 9229) mechanism of fragmentation of a2 ions which involves elimination of CO from the a2 ion to form a proton‐bound complex of two imines. Based on this mechanism ab initio calculations of the total energies of the a2 ions and the transition states for fragmentation have been carried out giving the energy barrier for fragmentation of each a2 ion. The experimental results are interpreted in terms of these energetics data, unimolecular rate constants calculated by using the RRKM theory, and the imine proton affinities. Copyright © 2004 John Wiley & Sons, Ltd.
RScore: a peptide randomicity score for evaluating tandem mass spectra
Authors: Li Fuxin , Sun Wei , Gao Youhe , Wang Jue
Published: July 2004

RScore, a new criterion of randomicity for evaluating tandem mass (MS/MS) spectra, is described. RScore is defined as the relative quality in cross‐correlation and matched intensity percentage of a potentially positive peptide to those of other possible candidates for the same spectrum. By utilizing RScore combined with less stringent SEQUEST score filters, the number of true positive peptides can be increased and the number of false positives in datasets from a known protein mixture can be reduced compared with current SEQUEST parameters used alone. This algorithm is simple and adds little overheads to SEQUEST computation. Copyright © 2004 John Wiley & Sons, Ltd.
Determination of N‐acetyl‐S‐(N‐methylcarbamoyl)cysteine (AMCC) in urine by high‐performance liquid chromatography combined with mass spectrometry
Authors: Perico A. , Baglioni S. , Bavazzano P.
Published: July 2004

A simple, sensitive and specific method for the quantification of N‐acetyl‐S‐(N‐methylcarbamoyl)cysteine (AMCC) in urines of the general population and of exposed workers has been developed. Samples were first diluted with phosphate buffer followed by purification by solid‐phase extraction (SPE) with SAX columns prior to analysis by liquid chromatography/mass spectrometry (LC/MS). An external standard was used for the quantification together with selected ion monitoring of m/z 219, [MH]−. The linear calibration curve showed a good correlation (r2 = 0.98, p < 0.001) between 0.1–110 mg/L of AMCC, and the detection limit was calculated to be 2 μg/L. The within‐day and between‐day precision, calculated for exposed workers and general population AMCC levels in urine samples, were determined as 1.2 and 3.6%, respectively (as relative standard deviation (RSD)). Copyright © 2004 John Wiley & Sons, Ltd.
Quantification of hydrogen cyanide in humid air by selected ion flow tube mass spectrometry
Authors: Španěl Patrik , Wang Tianshu , Smith David
Published: July 2004

Following our recent observation that Pseudomonas bacteria in vitro emit hydrogen cyanide, we have found it necessary to investigate the ion chemistry of this compound and to extend the kinetics database for selected ion flow tube mass spectrometry (SIFT‐MS) to allow the accurate quantification of HCN in moist air samples, including exhaled breath. Because of the proximity of the proton affinities of HCN and H2O molecules, the presence of water vapour can significantly distort HCN analysis in the presence of water vapour and a more sophisticated analytical procedure has to be developed. Thus, the reactions of H3O+(H2O)0,1,2,3 ions with HCN molecules have been studied in the presence of varying concentrations of water vapour, reactions on which SIFT‐MS analysis of HCN relies. The results of these experiments have allowed an analytical procedure to be developed which has extended the kinetics database of SIFT‐MS, such that HCN can now be quantified in humid air and in exhaled breath. Copyright © 2004 John Wiley & Sons, Ltd.
Rapid identification of environmental bacterial strains by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Ruelle Virginie , Moualij Benaissa El , Zorzi Willy , Ledent Philippe , Pauw Edwin De
Published: August 2004

In recent years, various mass spectrometry procedures have been developed for bacterial identification. The accuracy and speed with which data can be obtained by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) could make this a powerful tool for environmental monitoring. However, minor variations in the sample preparation can influence the mass spectra significantly. Therefore, the first objectives of this study were the adjustment and the optimization of experimental parameters allowing a rapid identification of whole bacterial cells without laborious sample preparation. The tested experimental parameters were matrix, extraction solvent, salt content, deposition method, culture medium and incubation time. This standardized protocol was applied to identify reference and environmental bacterial strains of Escherichia coli, Salmonella and Acinetobacter. The environmental bacterial strains were isolated from sewage sludge using an original microextraction procedure based on repeated sonications and enzymatic treatments. The bacterial identification was realized by the observation of the respective genus‐, species‐ and strain‐specific biomarkers. This bacterial taxonomy could be completed within one hour, with minimal sample preparation, provided that sufficient bacteria had been collected prior to MALDI‐TOF analysis. Copyright © 2004 John Wiley & Sons, Ltd.
ENDOW (efficient development of offshore wind farms): modelling wake and boundary layer interactions
Authors: Barthelmie Rebecca , Larsen Gunner , Pryor Sara , Jørgensen Hans , Bergström Hans , Schlez Wolfgang , Rados Kostas , Lange Bernhard , Vølund Per , Neckelmann Søren , Mogensen Søren , Schepers Gerard , Hegberg Terry , Folkerts Luuk , Magnusson Mikael
Published: July 2004

While experience gained through the offshore wind energy projects currently operating is valuable, a major uncertainty in estimating power production lies in the prediction of the dynamic links between the atmosphere and wind turbines in offshore regimes. The objective of the ENDOW project was to evaluate, enhance and interface wake and boundary layer models for utilization offshore. The project resulted in a significant advance in the state of the art in both wake and marine boundary layer models, leading to improved prediction of wind speed and turbulence profiles within large offshore wind farms. Use of new databases from existing offshore wind farms and detailed wake profiles collected using sodar provided a unique opportunity to undertake the first comprehensive evaluation of wake models in the offshore environment. The results of wake model performance in different wind speed, stability and roughness conditions relative to observations provided criteria for their improvement. Mesoscale model simulations were used to evaluate the impact of thermal flows, roughness and topography on offshore wind speeds. The model hierarchy developed under ENDOW forms the basis of design tools for use by wind energy developers and turbine manufacturers to optimize power output from offshore wind farms through minimized wake effects and optimal grid connections. The design tools are being built onto existing regional‐scale models and wind farm design software which was developed with EU funding and is in use currently by wind energy developers. Copyright © 2004 John Wiley & Sons, Ltd.
Insight into wind turbine stall and post‐stall aerodynamics
Authors: Tangler James L.
Published: July 2004

The objective of this study was to evaluate measured NASA Ames Unsteady Aerodynamic Experiment post‐stall blade element data and to provide guidelines for developing an empirical approach that predicts post‐stall aerofoil characteristics. Blade element data were analysed from the five radial stations of the baseline 5·03 m radius rotor. A lifting surface/prescribed wake performance prediction method was used to determine a reference angle of attack that corresponds to the measured blade element data. Using the measured normal and tangential force coefficients and estimated angle of attack, spanwise distributions of lift and drag performance characteristics were derived along with the circulation distributions. Guidelines for a new stall and post‐stall model based on the measured trends in the aerofoil performance characteristics, along with flat plate theory, are proposed for predicting the peak and post‐peak power. Copyright © 2004 John Wiley & Sons, Ltd.
Yeast Pho85 kinase is required for proper gene expression during the diauxic shift
Authors: Nishizawa Masafumi , Katou Yuki , Shirahige Katsuhiko , Toh‐e Akio
Published: August 2004

The budding yeast Saccharomyces cerevisiae changes its gene expression profile when environmental nutritional conditions are changed. Protein kinases including cyclic AMP‐dependent kinase, Snf1 and Tor kinases play important roles in this process. Pho85 kinase, a member of the yeast cyclin‐dependent kinase family, is involved in the regulation of phosphate metabolism and reserve carbohydrates, and thus is implicated to function as a nutrient‐sensing kinase. Upon depletion of glucose in the medium, yeast cells undergo a diauxic shift, accompanied by a carbon metabolic pathway shift, stimulation of mitochondrial function and downregulation of ribosome biogenesis and protein synthesis. We analysed the effect of a pho85Δ mutation on the expression profiles of the genes in this process to investigate whether Pho85 kinase participates in the yeast diauxy. We found that, in the absence of PHO85, a majority of mitochondrial genes were not properly induced, that proteasome‐related and chaperonin genes were more repressed, and that, when glucose was still present in the medium, a certain class of genes involved in ribosome biogenesis (ribosomal protein and rRNA processing genes) was repressed, whereas those involved in gluconeogenesis and the glyoxylate cycle were induced. We also found that PHO85 is required for proper expression of several metal sensor genes and their regulatory genes. These results suggest that Pho85 is required for proper onset of changes in expression profiles of genes responsible for the diauxic shift. Copyright © 2004 John Wiley & Sons, Ltd.
An efficiently regulated promoter system for Cryptococcus neoformans utilizing the CTR4 promoter
Authors: Ory Jeramia J. , Griffith Cara L. , Doering Tamara L.
Published: August 2004

Cryptococcus neoformans is an opportunistic fungal pathogen responsible for serious meningitis. Although many useful molecular tools have been developed for its study, there are currently few inducible promoters available for general use. To address this need, we have constructed expression plasmids incorporating upstream elements of the C. neoformans copper transporter gene CTR4, and tested them in C. neoformans serotypes A and D. In response to copper deprivation, these plasmids mediate high‐level expression of a reporter protein. This expression can be completely repressed using physiologically low concentrations of copper. Notably, this new family of copper‐sensing promoters demonstrates excellent expression in serotype A, contrasting with other available promoters. These plasmids therefore offer efficient and regulated expression for both serotypes A and D, and should be valuable tools for the C. neoformans research community. Copyright © 2004 John Wiley & Sons, Ltd.
Screening the yeast deletant mutant collection for hypersensitivity and hyper‐resistance to sorbate, a weak organic acid food preservative
Authors: Mollapour Mehdi , Fong Dahna , Balakrishnan Krishna , Harris Nicholas , Thompson Suzanne , Schüller Christoph , Kuchler Karl , Piper Peter W.
Published: August 2004

Certain yeasts cause large‐scale spoilage of preserved food materials, partly as a result of their ability to grow in the presence of the preservatives allowed in food and beverage preservation. This study used robotic methods to screen the collection of Saccharomyces cerevisiae gene deletion mutants for both increased sensitivity and increased resistance to sorbic acid, one of the most widely‐used weak organic acid preservatives. In this way it sought to identify the non‐essential, non‐redundant activities that influence this resistance, activities that might be the potential targets of new preservation strategies. 237 mutants were identified as incapable of growth at pH 4.5 in presence of 2 mM sorbic acid, while 34 mutants exhibit even higher sorbate resistance than the wild‐type parental strain. A number of oxidative stress‐sensitive mutants, also mitochondrial mutants, are sorbate‐sensitive. This appears to reflect the importance of sustaining a reducing intracellular environment (high reduced glutathione levels and NADH/NAD and NADPH/NADP ratios). Sorbate resistance is also very severely compromised in mutants lacking an acidified vacuole, in vacuolar protein sorting (vps) mutants, in mutants defective in ergosterol biosynthesis (erg mutants) and with several defects in actin and microtubule organization. Sorbate resistance is, however, elevated with the loss of the Yap5 transcription factor; with single losses of two B‐type cyclins (Clb3p, Clb5p); and with loss of a plasma membrane calcium channel activated by endoplasmic reticulum stress (Cch1p/Mid1p). Copyright © 2004 John Wiley & Sons, Ltd.
Searching clusters of community composition along multiple spatial scales: a case study on aquatic invertebrate communities in bamboo stumps in West Timor
Authors: Sunahara Toshihiko , Mogi Motoyoshi
Published: July 2004

We examined spatial heterogeneity at multiple scales in composition of the aquatic invertebrate communities in bamboo stumps in a mountainous area of West Timor. We partitioned the study area (ca. 15,000 m2) at five levels of patchiness: two sites, four sub‐sites, eight super‐clumps, 14 clumps, and 84 stumps. Similarity of community composition between stumps varied more than expected from independent occurrence of each taxon in comparisons within any levels of patches. Negative association was frequently detected among taxa. These results indicate heterogeneity in community composition at a stump level. At higher levels, similarity among stumps within each site was greater than expected from null models which assumed no spatial heterogeneity, and similarities among super‐clumps, sub‐sites and between sites in a whole area were lower than expected from the null models. The observed patterns in similarities among subsets of the community and distribution of each taxon were mostly consistent with the models which assumed site‐level heterogeneity. Therefore, we conclude that the community in this area was spatially heterogeneous at stump and site levels. The relationship between mean intra‐ and inter‐specific crowding suggested that the site level habitat heterogeneity might reduce the chance of encounters between two predators, the larvae of the Toxorhynchites mosquito and the Brachyceran fly.
Internal organisation of the nucleus: assembly of compartments by macromolecular crowding and the nuclear matrix model
Authors: Hancock Ronald
Published: August 2004

Abstract Many and possibly all macromolecules in the nucleus are segregated into discrete compartments, but the current model that this is achieved by a fibrillar nuclear matrix which structures the nuclear interior and compartments is not consistent with all experimental observations, as reviewed here. New results are presented which suggest that macromolecular crowding forces play a crucial role in the assembly of at least two compartments, nucleoli and PML bodies, and an in vitro system in which crowding assembles macromolecular complexes into structures which resemble nuclear compartments is described. Crowding forces, which are strong in the nucleus due to the high macromolecule concentration (in the range of 100 mg/ml), vastly increase the association constants of intermolecular interactions and can segregate different macromolecules into discrete phases. The model that they play a role in compartmentalisation of the nucleus is generally consistent with the properties of compartments, including their spherical or quasispherical form and their dynamic and mobile nature.
Prevalence of depression as measured by the CBDI in a predominantly adolescent school population in Turkey
Authors: Toros Fevziye , Gamsiz Bilgin N. , Bugdayci R. , Sasmaz T. , Kurt O. , Camdeviren H.
Published: August 2004

Objectives

This cross-sectional randomised study involving a predominantly adolescent school population (ranging from the 6th to the 11th grades) was conducted to determine the prevalence and clinical characteristics of depression in adolescents in the city of Mersin, Turkey.

Subjects and methods

A stratified sample of 4256 students was selected as representative of the city’s adolescent school population. The students were divided into two groups according to diagnosis (Group I: depressive adolescents; Group II: adolescents without depression). The age range varied between 10 and 20 years, with a mean of 14.53 years (S.D. = 1.89), i.e. a mean of 14.73 years (S.D. = 1.79) for Group I, and 15.5 years (S.D. = 1.9) for Group II. Data was obtained via two structured questionnaires designed to determine the presence and clinical characteristics of depression both in adolescents and in their parents. In addition, the Child Beck Depression Inventory (CBDI) was administered to all students participating in the study. After quality control of data, the study sample was reduced to 4143 adolescents. The mean age of the students was 11.23 ± 6.44 years, and the ratio of boys/girls was 1.19:1.

Results

The prevalence of depression according to the CBDI (cut-off point: 19) was found to be 12.55% in this study group, with a significantly higher prevalence of depression in girls than in boys. Binary regression analysis demonstrated that the most important factors involved in the onset of depression in adolescents were having problems with parents, staying down a grade, and humiliation at school, and that the most common symptoms were feelings of worthlessness/guilt, sadness, emptiness, irritability and somatic disorders.

Conclusion

This cross-sectional prospective randomised school-based study has examined sociodemographic and clinical characteristics of adolescents with depression in a student population. It was found that in this study group there was a relatively high level of depressive symptoms, with a clear predominance of females over males. Other clinical characteristics of adolescents with depression have been discussed in the context of previous investigations.
One-year course of the first vs. multiple episodes of depression—Polish naturalistic study
Authors: Rybakowski Janusz K. , Nawacka Dorota , Kiejna Andrzej
Published: August 2004

Purpose

The aim of the study was to compare a clinical course and treatment results of depression occurring as the first depressive episode, the second depressive episode or the third or further depressive episode. The study was 1-year, prospective, naturalistic observation made by Polish psychiatrists.

Methods

One-hundred and seventy-nine patients with the first depressive episode (group I), 170 patients with the second episode (group II) and 183 patients with the third or further episode of depression (group III) were compared. The main analysed variable was remission, defined as the score of ≤7 points on 17-item Hamilton depression rating scale (HDRS), after 6 and 12 months of observation.

Results

The groups of patients studied did not initially differ as to age, proportion of gender and intensity of depression. The percentages of remission after 6 months of observation in groups I.III were: 49%, 41% and 32%, and after 12 months 69%, 60% and 50%, respectively.

Conclusions.

The results obtained indicate that the course of subsequent depressive episodes is less favourable compared to the first depressive episode. The percentages of remission obtained in individual groups studied may have implications regarding duration of pharmacological treatment of depressive episode.
Functional characterization of the putative orphan neuropeptide G‐protein coupled receptor C26F1.6 in Caenorhabditis elegans
Authors: Mertens Inge , Vandingenen Anick , Meeusen Tom , Janssen Tom , Luyten Walter , Nachman Ronald J. , De Loof Arnold , Schoofs Liliane
Published: August 2004

In this study, we describe the cloning and the characterization of the third FMRFamide‐related peptide (FaRP) receptor in Caenorhabditis elegans, the VRFa receptor 1. Numerous structurally different FaRPs were synthesized and used to screen the orphan C26F1.6 receptor for activation. Two peptides ending in M(orL)VRFamide elicited a calcium response in receptor expressing mammalian cells. The response is dose‐dependent and appeared to be very specific, since very closely related FaRPs were less active, even the other peptides ending in M(orL)VRFamide. Pharmacological profiling of the most active peptide suggests that SMVRFa is the most active binding core. N‐terminal extension decreases peptide activity.
Role of amino‐acid residue 95 in substrate specificity of phosphagen kinases
Authors: Tanaka Kumiko , Suzuki Tomohiko
Published: August 2004

The purpose of this study is to elucidate the mechanisms of guanidine substrate specificity in phosphagen kinases, including creatine kinase (CK), glycocyamine kinase (GK), lombricine kinase (LK), taurocyamine kinase (TK) and arginine kinase (AK). Among these enzymes, LK is unique in that it shows considerable enzyme activity for taurocyamine in addition to its original target substrate, lombricine. We earlier proposed several candidate amino acids associated with guanidine substrate recognition. Here, we focus on amino‐acid residue 95, which is strictly conserved in phosphagen kinases: Arg in CK, Ile in GK, Lys in LK and Tyr in AK. This residue is not directly associated with substrate binding in CK and AK crystal structures, but it is located close to the binding site of the guanidine substrate. We replaced amino acid 95 Lys in LK isolated from earthworm Eisenia foetida with two amino acids, Arg or Tyr, expressed the modified enzymes in Escherichia coli as a fusion protein with maltose‐binding protein, and determined the kinetic parameters. The K95R mutant enzyme showed a stronger affinity for both lombricine (K
m=0.74 mM and k
cat/K
m=19.34 s−1 mM−1) and taurocyamine (K
m=2.67 and k
cat/K
m=2.81), compared with those of the wild‐type enzyme (K
m=5.33 and k
cat/K
m=3.37 for lombricine, and K
m=15.31 and k
cat/K
m=0.48 for taurocyamine). Enzyme activity of the other mutant, K95Y, was dramatically altered. The affinity for taurocyamine (K
m=1.93 and k
cat/K
m=6.41) was enhanced remarkably and that for lombricine (K
m=14.2 and k
cat/K
m=0.72) was largely decreased, indicating that this mutant functions as a taurocyamine kinase. This mutant also had a lower but significant enzyme activity for the substrate arginine (K
m=33.28 and k
cat/K
m=0.01). These results suggest that Eisenia LK is an inherently flexible enzyme and that substrate specificity is strongly controlled by the amino‐acid residue at position 95.