bluuebunny/crossref_metadata_2025 huggingface dataset:
Lymphocytic inflammation in childhood bronchiolitis obliterans
Authors: Mauad Thais , van Schadewijk Annemarie , Schrumpf Jasmijn , Hack C. Erik , Fernezlian Sandra , Garippo Ana L. , Ejzenberg Bernardo , Hiemstra Pieter S. , Rabe Klaus F. , Dolhnikoff Marisa
Published: June 2004

Childhood bronchiolitis obliterans (CBO) is an infrequent, severe disorder characterized by persistent obstructive respiratory symptoms after an acute episode of bronchiolitis. The viral etiology is most common, and adenovirus is the most frequently identified causative agent. Pathologically, the disease is characterized as constrictive type BO, with variable degrees of chronic inflammation and fibrosis in the bronchioles. The nature of the cellular infiltrate is largely unknown, and its characterization may provide better understanding of the disease and offer clues for therapy. Therefore, the aim of the present study was to characterize the inflammatory infiltrate in the bronchioles of 23 open lung biopsies of children with CBO and to compare this to the infiltrate in histologically normal airways. Our results show that CD3+ T cells were the most frequent cell type observed in CBO, with a predominance of the CD8+ T‐cell subtype. When compared to the control group, there was a larger number of CD8+, CD4+, CD20+, granzyme B+, and perforin+ lymphocytes in the CBO group. Further studies are needed to address the role of different cell types in the development of CBO. © 2004 Wiley‐Liss, Inc.
Asthma and acute chest in sickle‐cell disease
Authors: Boyd Jessica H. , Moinuddin Asif , Strunk Robert C. , DeBaun Michael R.
Published: June 2004

Our objective was to determine if physician‐diagnosed asthma increases the risk of acute chest syndrome (ACS) in children with sickle‐cell disease (SCD) hospitalized for pain. Our study design was a retrospective case‐control study of all SCD patients, aged 2–21 years, hospitalized for pain during the interval 1999–2000. Medical records of first admissions during the interval were reviewed to determine the presence of ACS during the admission. Cases were defined as patients with ACS, and controls were patients without ACS. Independently, medical records of admissions prior to the study interval were reviewed for evidence of physician‐diagnosed asthma. Sixty‐three cases with ACS and 76 controls without ACS were identified. No significant differences in gender, age, and hemoglobin phenotype were found. Patients with physician‐diagnosed asthma were 4.0 times (95% CI, 1.7, 9.5) more likely to develop ACS during the admission than patients without asthma. Individuals with physician‐diagnosed asthma had a longer hospitalization for ACS, i.e., 5.6 days vs. 2.6 days, respectively (P = 0.01). In conclusion, our preliminary data suggest that asthma in children with SCD admitted to the hospital for pain may be a risk factor for ACS and may increase the duration of hospitalization when compared to children with SCD and without asthma. © 2004 Wiley‐Liss, Inc.
Reduced eosinophil pro‐fibrogenic effect in severe childhood asthma compared to mild disease: An effect of corticosteroids?
Authors: Puxeddu Ilaria , Lack Gideon , Smith Susan J. , Levi‐Schaffer Francesca
Published: June 2004

Eosinophils play an important role in inflammation and probably in airway remodeling in asthma. We previously demonstrated that eosinophils from atopic subjects display pro‐fibrogenic properties towards lung fibroblasts partially by preformed transforming growth factor‐β (TGF‐β). We hypothesized that the pro‐fibrogenic potential of eosinophils is increased in children with life‐threatening asthma (LTA). Six children with atopic LTA clinically well‐controlled by inhaled corticosteroids (ICS) and 5 children with atopic mild asthma (MA) treated only with inhaled β2‐agonists were investigated. The effects of their peripheral blood eosinophils on fibroblast proliferation and lattice contraction were investigated. In addition, TGF‐β1 and IL‐6 eosinophil content were also evaluated. Unexpectedly, eosinophils from LTA increased fibroblast proliferation (5.4‐fold) and gel contraction (1.1‐fold) significantly less than those from MA. TGF‐β1 but not IL‐6 eosinophil content in LTA was significantly lower than that in MA (2.7‐fold). In vitro, addition of dexamethasone on eosinophils stimulated by mast cells resulted in a marked decrease in their TGF‐β1 content by 1.6‐fold. In conclusion, eosinophils from children with ICS‐treated LTA displayed significantly less pro‐fibrogenic properties than those from MA treated only with β2‐agonists. Our data suggest that the pro‐fibrogenic effect of eosinophils might be influenced by treatment with ICS in childhood asthma. © 2004 Wiley‐Liss, Inc.
Extracellular matrix remodeling in children with airway foreign‐body aspiration
Authors: Tang Lan Fang , Du Li Zhong , Chen Zhi Min , Zou Chao Chun
Published: June 2004

The purpose of this study was to observe extracellular matrix remodeling in children with airway foreign‐body aspiration (FBA) by detecting the expression of matrix metalloproteinase‐9 (MMP‐9), tissue inhibitor of matrix metalloproteinase‐1 (TIMP‐1), and hydroxyproline (HYP) in bronchoalveolar lavage fluid (BALF). Forty‐six children with FBA and 12 control subjects from 2002–2003 were enrolled in this study. The former were divided into three subgroups according to duration of foreign‐body (FB) retention (subgroup 1, <7 days; subgroup 2, 7–30 days; subgroup 3, >30 days). Cell count, and levels of MMP‐9, TIMP‐1, and HYP in BALF were measured. The total number of cells and differential counts detected in BALF did not differ significantly between patients and controls (P > 0.05), while mast cells were found only in the BALF of patients. The positive rates of MMP‐9 in controls, subgroup 1, subgroup 2, and subgroup 3 were 33.3%, 62.5%, 80.0%, and 93.3%, respectively, with a significant difference (P = 0.006). The positive rate of TIMP‐1 in controls and subgroups 1, 2, and 3 were 33.3%, 62.5%, 80.0%, and 93.3%, respectively, with a significant difference (P < 0.001) as well. HYP levels in subgroups 2 and 3 were significantly more increased than in subgroup 1 and controls (all P < 0.001). Levels of MMP‐9, TIMP‐1, and HYP in patients were positively correlated with duration of FB retention (all P < 0.05), and levels of MMP‐9 and TIMP‐1 were also positively correlated with percentage of mast cells in BALF (all P < 0.05). The differences in MMP‐9 and TIMP‐1 before and after FB removed were not significant (P > 0.05), while HYP levels decreased significantly after FB were removed (P = 0.001). Our findings support the hypothesis that FBA may contribute not only to mechanical airway obstruction, but also possibly to eventual airway remodeling by generation of MMPs and TIMPs. Pediatr Pulmonol. 2004; 38:140–145. © 2004 Wiley‐Liss, Inc.
Usefulness of a program of hospital‐supervised physical training in patients with cystic fibrosis
Authors: Turchetta Attilio , Salerno Teresa , Lucidi Vincenzina , Libera Flavia , Cutrera Renato , Bush Andrew
Published: June 2004

Exercise is an important part of normal childhood, but the ability to exercise may be impaired in chronic lung diseases such as cystic fibrosis (CF). Improving exercise performance by training is very attractive. The aim of the present study was the evaluation of the effects of a physical aerobic training program, performed in the Children's Hospital and Research Institute “Bambino Gesù” (Rome, Italy) in outpatient CF children, supervised by a physician. Twelve patients (mean forced expiratory flow in 1 sec (FEV1), 71%), age range 12–24 years (16.7 ± 4.4 years), were enrolled. They performed a maximal exercise stress test on the treadmill (modified Bruce protocol) with breath‐by‐breath determination of oxygen consumption (VO2) to maximum at end‐exercise; we measured time of exercise (TE), maximal heart rate (Hrmax) in beats per minute (bpm), and maximal systolic blood pressure (SBPm) in mmHg. The program consisted of 12 weeks of training twice a week. Each training session consisted of walking or running on the treadmill for 30 min at the speed that allowed the child to attain 60% of the maximal heart rate obtained during a baseline stress test for 4 weeks, 70% in the following 4 weeks, and 80% in the last 4 weeks, under strict medical supervision. HR was continously monitored. There was no change in FEV1 and forced vital capacity after the treatment period. Hrmax and SBPm also remained the same (P = 0.37 and P = 0.25, respectively). There was a significant increase in TE (P < 0.002), VO2, VO2/kg, and pulmonary ventilation (VE) (P < 0.0001, P < 0.001, and P < 0.001, respectively). This pilot study showed that a simple training program improves short‐term cardiopulmonary fitness in children with CF. Further studies with a larger sample and for a more prolonged time are necessary to assess if sport can have a long‐term effect on lung function or survival in CF patients. Pediatr Pulmonol. 2004; 38:115–118. © 2004 Wiley‐Liss, Inc.
Evaluation of tracheobronchial anomalies in children using low‐dose multidetector CT: Report of a 13‐year‐old boy with a tracheal bronchus and recurrent pulmonary infections
Authors: Heyer Christoph M. , Kagel Thomas , Lemburg Stefan P. , Nicolas Volkmar , Rieger Christian H.L.
Published: June 2004

Tracheobronchial anomalies in children may be associated with recurrent episodes of pulmonary infections and symptoms of recurrent or persistent airway obstruction. Diagnosis by conventional imaging may be difficult. Multidetector computed tomography (MDCT) offers the possibility to generate a virtual three‐dimensional bronchoscopy, thus enabling detailed overview of the tracheobronchial system. We report on a 13‐year old boy, admitted to hospital after recurrent episodes of bronchial infections. Functional studies showed airway obstruction with no response to bronchodilators. A chest radiograph was normal. Flexible bronchoscopy revealed tracheobroncho malacia of the distal trachea and the right main bronchus. The ostium of an accessory right‐sided tracheal bronchus, which could not be entered by the endoscope, was also detected. MDCT using a low‐dose protocol was performed on a four‐section scanner (Somatom Volume Zoom®, Siemens, Erlangen, Germany). A three‐dimensional virtual bronchoscopy based on surface rendering was generated, which confirmed moderate narrowing of the trachea and right main bronchus. Furthermore, an accessory and stenotic tracheal bronchus including poststenotic segments, ventilating parts of the right upper lobe, could be clearly visualized. MDCT can be a valuable instrument in the diagnostic pathway of assessing tracheobronchial anomalies in children, including visualization of poststenotic bronchial structures. The use of low‐dose protocols provides adequate image quality to perform virtual bronchoscopy, thus reducing administered radiation to a tolerable amount. Pediatr Pulmonol. 2004; 38:168–173. © 2004 Wiley‐Liss, Inc.
A simple method of reducing complications of pediatric nonbronchoscopic bronchoalveolar lavage
Authors: Morrow Brenda , Futter Merle , Argent Andrew
Published: June 2004

Our objective was to determine whether a simple method of maintaining positive pressure ventilation during nonbronchoscopic bronchoalveolar lavage (NB‐BAL) would successfully reduce the incidence and/or severity of desaturation events. Our design was a clinical trial with historical controls. Seventy ventilated pediatric patients undergoing diagnostic NB‐BAL participated. Two NB‐BAL techniques were compared: 1) the “unsealed” method, where the suction catheter was passed through an open system, maintaining oxygenation but not airway pressure; and 2) the “sealed” technique, which was identical except that the catheter was passed through a diaphragm, maintaining positive pressure ventilation throughout. NB‐BAL was performed on 35 patients using the “unsealed” technique and 2 years later on 35 patients using the “sealed” method. Heart rate and oxyhemoglobin saturation (SaO2) were recorded before, during, and after NB‐BAL. There was no difference between groups with regard to demographic data, oxygenation, or ventilatory requirements (P ≥ 0.1). The “sealed” group experienced a median drop in SaO2 of 6.0% (range, −6% to 44%), and the “unsealed” group a drop of 13.0% (−2% to 61%), during NB‐BAL (P < 0.05). Patients with oxygenation index greater than 10 experienced the most severe desaturation events in both groups: 53.8% of patients in the “sealed” group with oxygenation index >10 desaturated to <80% vs. 91.6% in the “unsealed” group (P < 0.05). In conclusion, we describe a simple, inexpensive modification of the NB‐BAL technique that reduces the incidence and severity of desaturation during NB‐BAL. © 2004 Wiley‐Liss, Inc.
Synthesis and anti‐mildew activity of 5‐(2‐aroyl)aryloxymethyl‐2‐phenyl‐1,3,4‐oxadiazoles against downy mildew of pearl millet
Authors: Khanum Shaukath A , Shashikanth Sheena , Sudha Belgur S , Deepak Saligrama A , Shetty Huntrike S
Published: June 2004

A manipulatively simple, rapid, high‐yielding and environmentally benign method for the integration of a heterocyclic ring, 1,3,4‐oxadiazole, at the benzophenone nucleus has been achieved through intramolecular cyclization of substituted aroylaryloxyacetohydrazides to substituted 5‐(2‐aroyl)aryloxy‐methyl‐2‐phenyl‐1,3,4‐oxadiazoles under solventless ‘dry’ conditions using montmorillonite K10 clay and microwave irradiation. A comparison is made of the microwave‐accelerated reaction with conventional heating conditions. Certain of the derivatives tested showed significant anti‐mildew activity against Sclerospora graminicola (Sacc) Schroeter, the downy mildew pathogen of pearl millet. Copyright © 2004 Society of Chemical Industry
Comparative analysis of neonicotinoid binding to insect membranes: I. A structure–activity study of the mode of [3H]imidacloprid displacement in Myzus persicae and Aphis craccivora
Authors: Kayser Hartmut , Lee Connie , Decock Arnaud , Baur Markus , Haettenschwiler Joerg , Maienfisch Peter
Published: June 2004

Neonicotinoids bind selectively to insect nicotinic acetylcholine receptors with nanomolar affinity to act as potent insecticides. While the members of the neonicotinoid class have many structural features in common, it is not known whether they also share the same mode of binding to the target receptor. Previous competition studies with [3H]imidacloprid, the first commercialised neonicotinoid, indicated that thiamethoxam, representing a novel structural sub‐class, may bind in a different way from that of other neonicotinoids. In the present work we analysed the mode of [3H]imidacloprid displacement by established neonicotinoids and newly synthesized analogues in the aphids Myzus persicae Sulzer and Aphis craccivora Koch. We found two classes of neonicotinoids with distinct modes of interference with [3H]imidacloprid, described as direct competitive inhibition and non‐competitive inhibition, respectively. Competitive neonicotinoids were acetamiprid, nitenpyram, thiacloprid, clothianidin and nithiazine, whereas thiamethoxam and the N‐methyl analogues of imidacloprid and clothianidin showed non‐competitive inhibition. The chloropyridine or chlorothiazole heterocycles, the polar pharmacophore parts, such as nitroimino, cyanoimino and nitromethylene, and the cyclic or acyclic structure of the pharmacophore were not relevant for the mode of inhibition. Consensus structural features of the neonicotinoids were defined for the two mechanisms of interaction with [3H]imidacloprid binding. Furthermore, two sub‐classes of non‐competitive inhibitors can be discriminated on the basis of their Hill coefficients for imidacloprid displacement. We conclude from the present data that the direct competitors share the binding site with imidacloprid, whereas non‐competitive compounds, like thiamethoxam, bind to a different site or in a different mode. Copyright © 2004 Society of Chemical Industry
Insecticidal activity of deoxypodophyllotoxin, isolated from Juniperus sabina L, and related lignans against larvae of Pieris rapae L
Authors: Gao Rong , Gao Congfen , Tian Xuan , Yu Xiangyang , Di Xudong , Xiao Hang , Zhang Xing
Published: June 2004

In the course of screening for naturally occurring insecticides from plants from the northwestern part of China, a petroleum ether extract of Juniperus sabina L was found to show insecticidal activity against fifth‐instar larvae of Pieris rapae L. From the extract, an insecticidal compound was isolated by bioassay‐guided fractionation. The compound was identified as deoxypodophyllotoxin (1) by comparison of its spectroscopic characteristics with literature data. In bioassays, 1 showed antifeedant activity against fifth‐instar larvae of P rapae at 0.05–1.00 g litre−1 and its AFC50 (concentration for 50% antifeedant activity) values at 12 and 48 h were 0.170 and 0.060 g litre−1, respectively. In that concentration range, all treated insects died within 48 h after treatment and compound 1 showed delayed insecticidal activity. At 0.015–0.100 g litre−1, 1 showed insecticidal activity, with an LC50 of 0.020 g litre−1. The related compound deoxypicropodophyllotoxin (2), however, showed lower antifeedant and insecticidal activities than 1 in bioassay. This indicated that the trans‐lactone ring is an important moiety for enhancing activity in these compounds. Comparison of the insecticidal activities of 1 and another related compound, podophyllotoxin (3), suggested that varying the substituent at C‐4 is an exciting possibility for synthesizing more potent analogues. Copyright © 2004 Society of Chemical Industry
Capacity analysis and system optimization for the forward link of multi‐beam satellite broadband systems exploiting adaptive coding and modulation
Authors: Rinaldo Rita , Gaudenzi Riccardo De
Published: June 2004

This paper proposes a methodology for designing and optimizing the performance of adaptive coding and modulation (ACM) schemes for the forward link of unicast satellite broadband networks. The proposed technique of general applicability is based on the overall system capacity maximization conditioned on meeting a certain service area coverage for a given outage probability. The paper first derives in detail the method for computing the Shannon‐based capacity of a multi‐beam satellite system adopting ACM. Then the link efficiency is optimized under different physical layer constraints allowing a more realistic system performance assessment. Finally, to exemplify the methodology application and to quantify the ACM system performance improvement capabilities a study case corresponding to a Ka‐band state‐of‐the‐art bent pipe satellite network is provided. The example illustrates the very substantial capacity gain offered by state‐of‐the‐art adaptive modulation and coding schemes utilization compared to current broadband satellite system design approach. Copyright © 2004 John Wiley & Sons, Ltd.
DVB‐S2 ACM modes for IP and MPEG unicast applications
Authors: Rinaldo R. , Vazquez‐Castro M. A. , Morello A.
Published: June 2004

The DVB‐S2 standard (ETSI: EN 302 307. Digital Video Broadcasting (DVB): second generation framing structure, channel coding and modulation systems for Broadcasting, Interactive Services, News Gathering and other broadband satellite applications (DVB‐S2)) has been conceived for several satellite broadband applications: Television Broadcast Services, Interactive Services including Internet Access by consumers, Professional Applications such as Digital Satellite News Gathering (DSNG) and TV distribution, data trunking. This paper focuses on the profiles supporting interactive type of services, for which Adaptive Coding and Modulation (ACM) has been included in the new generation of the standard. Following the DVB‐S2 specifications, a number of modem configurations and tools are made available for implementing ACM in interactive systems. However, the different approaches have important impacts on the design of the system architecture and of the scheduling/resource management algorithms. The aim of the present contribution is providing a first discussion on the critical issues at system and MAC level, which need to be addressed when implementing a DVB‐S2 ACM system. A general introduction to ACM is also provided, as well as an illustration of the key elements included in the DVB‐S2 standard for supporting physical layer adaptivity. Copyright © 2004 John Wiley & Sons, Ltd.
The impact of firm and environmental characteristics on international joint venture (IJV) marketing performance in Thailand
Authors: Julian Craig , O'Cass Aron
Published: June 2004

International joint ventures (IJVs) have become an important means of market entry for many firms, particularly those seeking entry into Asia (Lin & Germain, 1999). This study examines firm and environmental characteristics that impact the overall satisfaction with marketing performance and economic performance of IJVs in Thailand. The data for this study were collected via a mail survey of 1,047 Thai‐foreign IJVs in Thailand. The analysis indicated that IJV marketing performance was influenced by market characteristics, commitment, marketing orientation, and organizational control and that these variables differentially impact overall satisfaction with marketing performance and economic performance. © 2004 Wiley Periodicals, Inc.
Doing business in South Africa
Authors: van Wyk Jay , Custy Mary C.
Published: June 2004

This survey of the South African business environment outlines the major transformations the country has experienced since 1994. The economy has been restructured, which enhanced fiscal and monetary discipline as well as domestic and global competitiveness. The general business climate has been improved, but continued progress requires (1) prioritization of social issues such as HIV/AIDS, employment, and crime and (2) accelerated privatization, market reforms, and clarity about black economic empowerment. Such changes may stimulate inflation‐rate reduction, foreign exchange stability, and an increase in foreign direct investment. © 2004 Wiley Periodicals, Inc.
Research note: The internet's impact on export channel structure
Authors: Li Lee
Published: June 2004

This study explores the Internet's impact on export channel structure. Findings from this study suggest that the Internet does not have a considerable impact on the export channel structure of those manufacturers that adopt differential pricing policies and market separation policies. Export manufacturers that pursue broad targeting or experience dominant distributors may keep their traditional channel structure as well. However, export manufacturers that face tough competition or short product life cycles have to change their traditional channel structure to fit the market changes caused by the Internet. © 2004 Wiley Periodicals, Inc.
Capitalist China: Strategies for a revolutionized economy
Authors: Reid David McHardy
Published: June 2004

Jonathan R. Woetzel. 2003.Capitalist China: Strategies for a Revolutionized Economy.New York: John Wiley & Sons. 250 pages. ISBN: 0‐470‐82108‐6.
Globalization and its discontents
Authors: Finnegan Carol A.
Published: June 2004

Joseph E. Stiglitz. 2002.Globalization and Its Discontents.New York: W.W. Norton & Company. xxii + 282 pages. ISBN: 0‐393‐05124‐2.
Development of poly(vinyl chloride)/wood composites. A literature review
Authors: Jiang Haihong , Kamdem D. Pascal
Published: June 2004

Poly(vinyl chloride)/wood fiber (flour) composites are currently experiencing a dramatic increase in use. Most of them are used to produce window/door profiles, decking, railing, and siding by using conical counterrotating intermeshing twin‐screw extruders. Heat stabilizers, processing aids, impact modifiers, lubricants, and pigments are still important for PVC/wood composite formulations. Poly[methylene(polyphenyl isocyanate)] (PMPPIC), γ‐aminopropyltriethoxysilane, maleated polypropylene (MAPP), and copper metallic complex have proved to be effective coupling agents for this composite system. Mechanical properties of PVC/wood composites can be enhanced by combining wood with mica or glass fibers to form hybrid reinforcements. Ultraviolet light resistance and weathering dimensional stabilities of PVC/wood composites are superior to those of natural wood. Density reduction can be achieved through the microcellular foaming technique by using chemical blowing agents, such as azodicarbonamide and sodium bicarbonate, or physical blowing agents, such as carbon dioxide. J. Vinyl Addit. Technol. 10:59–69, 2004. © 2004 Society of Plastics Engineers.
Effects of copper amine treatment on mechanical properties of PVC/wood‐flour composites
Authors: Jiang Haihong , Kamdem D. Pascal
Published: June 2004

Copper amine–treated wood flour was added to PVC [poly(vinyl chloride)] matrix in order to manufacture PVC/wood‐flour composites. Effects of copper treatments on the mechanical properties of PVC‐wood composites were evaluated. Unnotched impact strength, flexural strength, and flexural toughness of the composites were significantly improved by the wood‐flour copper treatment. The optimum copper concentration range was 0.2 to 0.6 wt% of wood flour. Fractured surfaces were examined by using scanning electron microscopy (SEM) combined with energy‐dispersive spectroscopy (EDS). PVC/wood interfacial debonding was the main fracture mode of untreated wood‐flour composites, whereas wood‐particle pullout and breakage dominating the fractured surfaces of copper‐treated wood‐flour composites. On the fractured surfaces, more PVC could be found on the exposed copper‐treated wood particles than on untreated wood, a result suggesting improved PVC‐wood interfacial adhesion after copper treatments. J. Vinyl Addit. Technol. 10:70–78, 2004. © 2004 Society of Plastics Engineers.
Antimony/iron interactions in chlorinated polymer blends
Authors: Carty Peter , Price Dennis
Published: June 2004

The flammability properties of blends of acrylonitrile‐butadiene‐styrene (ABS) and chlorinated poly(vinyl chloride) (CPVC) have been investigated. Additive‐free ABS/CPVC blends, blends containing an iron(III) based smoke suppressant, basic iron(III) oxide (FeOOH) and blends containing equal amounts of the commercially available flame retardant, antimony(III) oxide (Sb2O3) and FeOOH were prepared. Char formation at 650°C, flammability (Oxygen Index) and smoke density (flaming‐mode‐NBS Smoke Density Chamber) data was obtained using standard procedures. Char formation in these systems was found to be linearly dependent on the chlorine content of the blends, even in the presence of antimony(III) oxide and basic iron(III) oxide. Oxygen index values for the additive‐free blends vary with blend composition (non‐linear) but the presence of FeOOH and Sb2O3/FeOOH combinations in the blends raise oxygen index values, especially at low (∼20%) chlorine concentrations. Smoke density values for the additive‐free blends are linearly dependent on chlorine content, but the additives have different effects on smoke formation, effects that also depend on the chlorine content of the blends. Attempts to relate these changes in flammability parameters to chemical interactions occurring between polymers and additives during thermal decomposition are discussed. J. Vinyl Addit. Technol. 10:88–94, 2004. © 2004 Society of Plastics Engineers.
Extending the use of zinc‐containing biocides in PVC
Authors: Burley Joseph W. , Clifford Patrick D.
Published: June 2004

While zinc is a crucial element in the formulation of many PVC stabilizers, high levels negatively affect heat and shear stabilities of PVC formulations. Thus, the use of zinc‐containing biocides in PVC has been limited to plastisol formulations, which are not subjected to the heat and shear histories of calendered and extruded formulations. Patented technology has been developed that overcomes many of the stability issues raised by the addition of zinc‐containing biocides to PVC. Specifically, the use of hydrotalcites in combination with zinc pyrithione improves sensitivity to heat and shear as well as retention of the antimicrobial activity of the zinc additive. J. Vinyl Addit. Technol. 10:95–98, 2004. © 2004 Society of Plastics Engineers.
Organophosphite transformations in flexible PVC formulations
Authors: Jakupca Michael R. , Harr Mark E. , Stevenson Don R.
Published: June 2004

Organophosphites are a versatile component of liquid PVC heat stabilizers and stabilize PVC through a variety of mechanisms. Organophosphites can decompose peroxides, replace labile chlorines on the PVC backbone, scavenge HCl (via the Arbuzov rearrangement), complex Lewis acids, and add to double bonds. This paper attempts to identify the relative contributions of these mechanisms in both model systems and flexible PVC formulations. J. Vinyl Addit. Technol. 10:99–103, 2004. © 2004 Society of Plastics Engineers.
Enhancing collaborative tendencies: Extending the single identity model for youth conflict education
Authors: Jones Tricia S.
Published: June 2004

A conflict intervention in postapartheid South Africa suggests new insights into encouraging an honest and engaging participation in the dialogue process.
Seeds of peace: Toward a common narrative
Authors: van Woerkom Marieke
Published: June 2004

In the woods of Maine, young people from conflict regions meet to learn about themselves, each other, and their potential to promote peace.
Are reconstructed pre‐instrumental hemispheric temperatures consistent with instrumental hemispheric temperatures?
Authors: Andronova N. G. , Schlesinger M. E. , Mann M. E.
Published: June 2004

Reconstructions of Northern Hemisphere near‐surface temperatures from climate ‘proxy’ data such as tree rings, ice cores, and corals, suggest that late 20th century Northern Hemisphere mean warmth is anomalous in the context of the past several centuries and likely at least the past two millennia. Though substantial uncertainties in the paleoclimate reconstructions exist, these findings add to the evidence for a discernible human influence on climate. Here we use our simple climate model with six radiative‐forcing reconstructions and climate sensitivity determined from instrumental temperatures over 1861 to 1997 to simulate the forced pre‐instrumental hemispheric‐average temperatures from 1500 to 1895. The model‐simulated pre‐instrumental temperatures indicate that the proxy temperature reconstructions are consistent with the instrumental temperatures in the Northern Hemisphere, but are too warm in the Southern Hemisphere.
Decadal‐scale climate drivers for glacial dynamics in Glacier National Park, Montana, USA
Authors: Pederson Gregory T. , Fagre Daniel B. , Gray Stephen T. , Graumlich Lisa J.
Published: June 2004

Little Ice Age (14th–19th centuries A.D.) glacial maxima and 20th century retreat have been well documented in Glacier National Park, Montana, USA. However, the influence of regional and Pacific Basin driven climate variability on these events is poorly understood. We use tree‐ring reconstructions of North Pacific surface temperature anomalies and summer drought as proxies for winter glacial accumulation and summer ablation, respectively, over the past three centuries. These records show that the 1850's glacial maximum was likely produced by ∼70 yrs of cool/wet summers coupled with high snowpack. Post 1850, glacial retreat coincides with an extended period (>50 yr) of summer drought and low snowpack culminating in the exceptional events of 1917 to 1941 when retreat rates for some glaciers exceeded 100 m/yr. This research highlights potential local and ocean‐based drivers of glacial dynamics, and difficulties in separating the effects of global climate change from regional expressions of decadal‐scale climate variability.
Dynamics of an ice continent on Titan
Authors: Perron J. Taylor , de Pater Imke
Published: June 2004

If the large, high‐albedo surface feature on Titan's leading hemisphere is an elevated “continent” composed mainly of water ice, it will deform under its own weight. We present a model for the axisymmetric spreading of this hypothesized continent based on the similarity solution of Halfar [1983] and the approach of Nye [2000]. We find that the thickness of the model continent is dictated by the spreading time, whereas topographic relief is controlled primarily by isostatic effects. For a mantle density of 1000 kg m−3, the relief of an isostatically supported continent on Titan is not likely to exceed ∼3–7 km.
Impacts of winter‐NAO on March cooling trends over subtropical Eurasia continent in the recent half century
Authors: Yu Rucong , Zhou Tianjun
Published: June 2004

At odds with global warming trends, surface air temperature over large subtropical Eurasia continent in spring March exhibits unique strong cooling over the last half century. The cause for this cooling is shown to be related to Winter (DJF) North Atlantic Oscillation (W‐NAO). Positive values of W‐NAO provoke cooling signals in northern Africa continent simultaneously from surface to tropopause. The W‐NAO generated signals barotropically extend eastward over most of subtropical Eurasia and reaches eastern China in March.
A new 1.6‐micron map of Titan's surface
Authors: Roe H. G. , de Pater I. , Gibbard S. G. , Macintosh B. A. , Max C. E. , Young E. F. , Brown M. E. , Bouchez A. H.
Published: June 2004

We present a new map of Titan's surface obtained in the spectral ‘window’ at ∼1.6 μm between strong methane absorption. This pre‐Cassini view of Titan's surface was created from images obtained using adaptive optics on the W.M. Keck II telescope and is the highest resolution map yet made of Titan's surface. Numerous surface features down to the limits of the spatial resolution (∼200–300 km) are apparent. No features are easily identifiable in terms of their geologic origin, although several are likely craters.
A tree‐ring based reconstruction of the Atlantic Multidecadal Oscillation since 1567 A.D.
Authors: Gray Stephen T. , Graumlich Lisa J. , Betancourt Julio L. , Pederson Gregory T.
Published: June 2004

We present a tree‐ring based reconstruction of the Atlantic Multidecadal Oscillation (AMO) which demonstrates that strong, low‐frequency (60–100 yr) variability in basin‐wide (0–70°N) sea surface temperatures (SSTs) has been a consistent feature of North Atlantic climate for the past five centuries. Intervention analysis of reconstructed AMO indicates that 20th century modes were similar to those in the preceding ∼350 yr, and wavelet spectra show robust multidecadal oscillations throughout the reconstruction. Though the exact relationships between low‐frequency SST modes, higher frequency (∼7–25 yr) atmospheric modes (e.g., North Atlantic Oscillation/Arctic Oscillation), and terrestrial climates must still be resolved, our results confirm that the AMO should be considered in assessments of past and future Northern Hemisphere climates.
Wind observations of asymmetric magnetic reconnection in the distant magnetotail
Authors: Øieroset Marit , Phan Tai D. , Fujimoto Masaki
Published: June 2004

On February 23, 2001, during southward and strongly dawnward IMF, Wind traversed the distant magnetotail near XGSM = −90 RE. Wind encountered the mantle in the southern hemisphere and a nearly empty lobe in the northern hemisphere. In the current layer (plasma sheet), high‐speed tailward plasma jets with plasma density intermediate between the mantle and the lobe were detected. The speed of these flows were 96–99% of the Alfvén speed measured in the deHoffmann‐Teller frame. We interpret these observations as evidence for asymmetric reconnection involving a rotational discontinuity in the distant tail when the density in the two inflow regions are vastly different. This is in contrast to typical symmetric magnetotail reconnection involving two lobes of equal density where the flow acceleration across the slow shock is usually sub‐Alfvénic and the outflow density is enhanced relative to the inflow density. Hall effects are also observed in this event.
Frequency-domain “single-shot” ultrafast transient absorption spectroscopy using chirped laser pulses
Authors: Shkrob Ilya A. , Oulianov Dmitri A. , Crowell Robert A. , Pommeret Stanislas
Published: June 2004

Single-shot ultrafast transient absorbance spectroscopy based on the frequency encoding of kinetics is demonstrated. The kinetics are sampled in the frequency domain using linearly chirped, amplified 33 fs pulses derived from a Ti:sapphire laser. A variable length grating pair compressor is used to achieve sampling of 512 channels with a 2–160 ps window with sensitivity>5×10−4. In terms of the acquisition time, frequency-domain “single-shot” (FDSS) spectroscopy has an advantage over pump–probe spectroscopy when “noise” is dominated by variations in the amplitude of the signal due to pump and flow instability. Unlike some other single-shot techniques, FDSS can be used for fluid samples flowing in a high-speed jet and for thin solid samples that exhibit interference fringes. Another advantage is that, due to interference of quasimonochromatic components of the chirped probe pulse, an oscillation pattern near the origin of the FDSS kinetics emerges. This pattern is unique and can be used to determine the complex dielectric function of photogenerated species. The advantages of FDSS are illustrated with the kinetics obtained in multiphoton ionization of aqueous iodide and one-photon excitation of polycrystalline ZnSe.
Spectroscopy of K+⋅Rg and transport coefficients of K+ in Rg (Rg=He–Rn)
Authors: Viehland Larry A. , Lozeille Jérôme , Soldán Pavel , Lee Edmond P. F. , Wright Timothy G.
Published: June 2004

Ab initio calculations employing the coupled-cluster method, with single and double substitutions and accounting for triple excitations noniteratively [CCSD(T)], are used to obtain accurate potential energy curves for the K+⋅He, K+⋅Ne, K+⋅Ar, K+⋅Kr, K+⋅Xe, and K+⋅Rn cationic complexes. From these potentials, rovibrational energy levels and spectroscopic parameters are calculated. In addition, mobilities and diffusion coefficients for K+ cations moving through the six rare gases are calculated, under conditions that match previous experimental determinations. A detailed statistical comparison of the present and previous potentials is made with available experimental data, and critical conclusions are drawn as to the reliability of each set of data. It is concluded that the present ab initio potentials match the accuracy of the best model potentials and the most reliable experimental data.
Fluorocarbon plasma etching of silicon: Factors controlling etch rate
Authors: Humbird David , Graves David B.
Published: June 2004

Molecular dynamics simulations of CF2, F, and Ar+ impacting silicon surfaces were conducted to understand the mechanisms controlling steady-state etching in typical fluorocarbon (FC) plasmas. The simulations reveal the central importance of a mixed amorphous silicon carbide (a-Si:C) top layer that forms due to ion impact and ion-induced mixing. This layer of a-Si:C forms to a depth that depends on ion energy and the composition of the radicals impacting the surface. With only thermal CF2 and 200 eV Ar+, the a-Si:C layer stops the etching of the underlying Si. Adding as little as 1 F per ion reduces the thickness and increases the permeability of this layer, resulting in steady etching of the underlying Si. A mixed Si–C layer forms whenever C sticks to the Si surface in the presence of energetic bombardment. The FC polymer and bare Si etch much faster than the a-Si:C layer, suggesting that the competition to form and destroy this layer is key in controlling the Si etch rate in FC plasmas under some conditions. The FC polymer that forms on Si surfaces, under the conditions studied in the simulations, plays an indirect role in etching by supplying both C and F that subsequently mix into the underlying layers due to the impact of energetic species such as Ar+.
Electrochemically assembled p-type Bi2Te3 nanowire arrays
Authors: Wang Wei , Huang Qinghua , Jia Falong , Zhu Jing
Published: June 2004

Polycrystalline Bi2Te3 nanowires with diameter about 50 nm have been assembled into the nanopores of alumina template by electrodeposition in the solution containing Bi3+ and HTeO2+ with porous alumina template as a cathode. X-ray photoelectron spectroscopy, high-resolution electron microscopy, and selected area electron diffraction investigations indicate that the nanowires are polycrystalline Bi2Te3 with hexagonal structure. Transmission electron microscopy and environmental scanning electron microscopy are used to characterize the morphology of the Bi2Te3 nanowire arrays. The performance measurements verified that the Seebeck coefficient of p-type Bi2Te3 nanowire arrays prepared in our lab was 270 μV/K at 306 K, which is larger than that of bulk Bi2Te3 thermoelectric materials. The temperature dependence of the resistance of the nanowire arrays was also measured, and it showed a semiconductive characteristic.
Experimental and theoretical study of demagnetization fields in superconducting samples of orthorhombic shape
Authors: Navau C. , Cardoso C. A. , de Lima O. F. , Araujo-Moreira F. M.
Published: June 2004

In this work we present a model for the calculation of the magnetic properties of superconductors of orthorhombic shape in the perfect shielding state when an external uniform magnetic field is applied in the direction of one of the principal axes of the sample. Our model accounts for demagnetization effects and it is free of fitting parameters and boundary value conditions. We consider planar linear circuits that lie perpendicular to the direction of the applied field. Calculation of the value of the currents is based on magnetic energy minimization. The model is proved to be accurate enough to reproduce experimental results as long as the dimension along the applied field is not much lower than the other dimensions. Calculations of surface currents, as well as measurements and calculations of magnetization and initial susceptibility, are reported. We also present an empirical formula that provides a good fit to the initial susceptibility of a general sample of orthorhombic shape. Demagnetization effects observed on the experimental results are explained in terms of the induced currents in the superconductor.
Ge films grown on Si substrates by molecular-beam epitaxy below 450 °C
Authors: Liu J. , Kim H. J. , Hul’ko O. , Xie Y. H. , Sahni S. , Bandaru P. , Yablonovitch E.
Published: June 2004

Ge thin films are grown on Si(001) substrates by molecular-beam epitaxy at 370 °C. The low-temperature epitaxial growth is compatible with the back-end thermal budget of current generation complementary metal-oxide-semiconductor technology, which is restricted to less than 450 °C. Reflection high-energy electron diffraction shows that single-crystal Ge thin films with smooth surfaces could be achieved below 450 °C. Double-axis x-ray θ/2θ scans also show that the epitaxial Ge films are almost fully strain-relaxed. As expected, cross-sectional transmission electron microscopy shows a network of dislocations at the interface. Hydrogen and oxide desorption techniques are proved to be necessary for improving the quality of the Ge films, which is reflected in improved minority carrier diffusion lengths and exceptionally low leakage currents.
Spherical particle in Poiseuille flow between planar walls
Authors: Jones R. B.
Published: June 2004

We study a spherical mesoparticle suspended in Newtonian fluid between plane-parallel walls with incident Poiseuille flow. Using a two-dimensional Fourier transform technique we obtain a symmetric analytic expression for the Green tensor for the Stokes equations describing the creeping flow in this geometry. From the matrix elements of the Green tensor with respect to a complete vector harmonic basis, we obtain the friction matrix for the sphere. The calculation of matrix elements of the Green tensor is done in large part analytically, reducing the evaluation of these elements to a one-dimensional numerical integration. The grand resistance and mobility matrices in Cartesian form are given in terms of 13 scalar friction and mobility functions which are expressed in terms of certain matrix elements calculated in the spherical basis. Numerical calculation of these functions is shown to converge well and to agree with earlier numerical calculations based on boundary collocation. For a channel width broad with respect to the particle radius, we show that an approximation defined by a superposition of single-wall functions is reasonably accurate, but that it has large errors for a narrow channel. In the two-wall geometry the friction and mobility functions describing translation–rotation coupling change sign as a function of position between the two walls. By Stokesian dynamics calculations for a polar particle subject to a torque arising from an external field, we show that the translation–rotation coupling induces sideways migration at right angles to the direction of fluid flow.
Experimental and theoretical study of the structures and binding energies of eugenol (H2O)n, n=0–2
Authors: Longarte Asier , Unamuno Iñigo , Fernández José A. , Castaño Fernando , Redondo Carolina
Published: June 2004

Eugenol (4-Allyl-2-methoxyphenol), a phenol-derivative with an intramolecular –OH⋯OCH3 hydrogen bond (H bond), has been studied in a supersonic expansion using a number of complementary laser spectroscopic techniques. The mass-resolved excitation spectrum of eugenol and its water complexes are reported for the first time. The most intense set of bands on the resonantly enhanced multiphoton ionization (REMPI) spectrum of eugenol originate in a conformer whose S1←S0 transition is at 35 202 cm−1 and the ionization threshold at (I0←S0) 62 544±150 cm−1 (7.755±0.019 eV). In addition, two low intensity features redshifted with respect to the 000 transition have been identified as due to a second, less stable conformer. Ab initio calculations show that the potential energy landscape depicts at least three minima associated with one folded and two extended conformers, one of which is the most stable. Clusters of eugenol/water were prepared in a supersonic expansion by seeding eugenol and water in noble gas He and examined by two-color REMPI (R2PI) and IR-UV double resonance spectroscopies. Only one single isomer was observed for both 1:1 and 1:2 complexes, in contrast with the several stable conformers provided by the computations. The dissociation energies of the 1:1 and 1:2 complexes have been determined by the fragmentation threshold method and the results compared with those from ab initio calculations conducted at the B3LYP and MP2 levels with a variety of basis sets.
Using path sampling to build better Markovian state models: Predicting the folding rate and mechanism of a tryptophan zipper beta hairpin
Authors: Singhal Nina , Snow Christopher D. , Pande Vijay S.
Published: June 2004

We propose an efficient method for the prediction of protein folding rate constants and mechanisms. We use molecular dynamics simulation data to build Markovian state models (MSMs), discrete representations of the pathways sampled. Using these MSMs, we can quickly calculate the folding probability (Pfold) and mean first passage time of all the sampled points. In addition, we provide techniques for evaluating these values under perturbed conditions without expensive recomputations. To demonstrate this method on a challenging system, we apply these techniques to a two-dimensional model energy landscape and the folding of a tryptophan zipper beta hairpin.