bluuebunny/crossref_metadata_2025 huggingface dataset:
Degradation of Recycled Polyethylene Film Materials Due to Contamination Encountered in the Products' Life Cycle
Authors: Marsh R , Griffiths A. J. , Williams K. P. , Evans S. L.
Published: June 2006

The recycling of polyethylene (PE) film is a straightforward process, provided the material that is being recycled has come from a clean source and is consistent in composition. Most waste film recovered for recycling has been subjected to a series of ‘life cycle factors’, e.g. comingling with wastes such as dirt, packaging tapes, and other plastic film products. Such contamination can degrade the material's physical properties and this article presents quantitative data on the effects of contaminants on PE films. Results suggest that dirt contamination can adversely affect the elasticity and melt viscosity of the polymer, but the contaminant does not interact directly with it and that polypropylene-based packaging tape is more suited to mechanical recycling than polyvinyl chloride or cellulose-based tapes.
Energy Losses in Viscoelastic Golf Balls
Authors: Strangwood M , Johnson A D G , Otto S R
Published: June 2006

The compression behaviour of a number of commercial two-piece and three-piece golf balls has been determined at both low- (compression testing) and high- (impact testing) strain rates. The hysteresis determined for slow strain rate testing has been correlated with the energy losses in impact studies (coefficient of restitution values) for some two-piece balls. The core mechanical properties dominate the ball behaviour in these examples. When the two-piece ball cover has a significantly higher Shore D hardness (and hence modulus) than the core, then the cover provides constraint during loading and unloading. This reduces the viscous part of core deformation so that lower energy losses are experienced at high strain rates than that would be expected from low strain rate testing of core mechanical properties alone. The characterization of three-piece balls would suggest that the mantle (outer core) acts in a similar way to a significantly harder cover and that the ball performance is not determined solely by the core mechanical properties.
The Effect of Cyclic Loading on the Stiffness and Damping Factors in the Midsoles of Running Shoes
Authors: Walker C
Published: June 2006

McMahon and Greene showed, in 1979, that it is possible to design a running track with a compliance that will reduce the shock loading on the legs of the athletes, and yet will enable them to return fast times. Since then, attempts have been made to find a combination of properties in a running shoe that would achieve the same ends. The extent to which the stiffness of the midsole may be reduced is limited by the need for the athlete's ankle to maintain a high degree of stability. On the other hand, it has been predicted from modelling studies that the damping properties of running shoe midsoles may be controlled to reduce the impact shock that is imparted to each leg of a runner, as the heel strikes the ground at the initiation of the contact phase.

A method has been developed for deriving the damping parameters (logarithmic decrement and damping factor) from an analysis of the complete load deformation curve, both for a single cycle and after several thousand load cycles. The stiffness and damping properties of five types of running shoes have been measured under low frequency loading, and also at 1 Hz - close to the frequency of heelstrike. It was found that although the damping factors range from 0.02 to 0.04 at low frequency, they are reduced to a range between 0.013 and 0.03 when the load is cycled at 1 Hz. In a similar fashion, the stiffness values increased under cyclic loading, so that the energy absorbed by the midsole was reduced by about a factor of two. These findings were found to be repeated across all the types of shoes that were tested, and related to the basic deformation mechanisms in the polymers used in the midsoles.
Design and Performance of Ropes for Climbing and Sailing
Authors: McLaren A J
Published: June 2006

Ropes are an important part of the equipment used by climbers, mountaineers, and sailors. On first inspection, most modern polymer ropes appear similar, and it might be assumed that their designs, construction, and properties are governed by the same requirements. In reality, the properties required of climbing ropes are dominated by the requirement that they effectively absorb and dissipate the energy of the falling climber, in a manner that it does not transmit more than a critical amount of force to his body. This requirement is met by the use of ropes with relatively low longitudinal stiffness. In contrast, most sailing ropes require high stiffness values to maximize their effectiveness and enable sailors to control sails and equipment precisely. These conflicting requirements led to the use of different classes of materials and different construction methods for the two sports. This paper reviews in detail the use of ropes, the properties required, manufacturing techniques and materials utilized, and the effect of service conditions on the performance of ropes. A survey of research that has been carried out in the field reveals what progress has been made in the development of these essential components and identifies where further work may yield benefits in the future.
Construction of the Finite-Element Models of Golf Balls and Simulations of Their Collisions
Authors: Tanaka K , Sato F , Oodaira H , Teranishi Y , Sato F , Ujihashi S
Published: June 2006

The purpose of this study is to construct a finite-element (FE) model of golf balls with hyperelasticity and viscoelasticity and to devise a method for construction of FE ball models by investigating the relationship between the material properties and the behaviour of the golf ball during and after impact. As for the material model of the FE ball model, the Mooney-Rivlin model and the three-element viscoelastic model were used. In the FE analysis (FEA), normal and oblique impacts with a rigid body were simulated with these models. The impact load, deformation of the ball, rebound velocity, angle, and spin rate were investigated, and their effects on the behaviour of the ball were analysed by varying the individual material constants which make up the ball models. Then, a method for the construction of an FE ball model was proposed, based on these relationships. Impact experiments were also conducted to obtain the dynamic properties of the golf ball. The solutions of the FEA of the ball model, as constructed by the proposed method, closely matched with the experimental results, and the method was verified by applying the process to other types of golf balls.
The Absorption Spectra of pH Indicator Dyes Doped in Silica Thin Films Prepared by the Method of Liquid Phase Deposition and the Spectroscopic Estimation of Effective Acidity of Internal Hydroxyl Groups of Silica
Authors: Suzuki Satoshi , Tokou Naoaki , Mabuchi Toshiaki , Nakajima Tsuyoshi , Ino Juichi , Takemura Kazuo , Kawahara Hideo
Published: July 2006

The method of liquid phase deposition (LPD) is a wet process forming hard and transparent silica thin films on glass surfaces and has interesting features, such as some organic molecules can be directly doped inside silica phases. The pH indicator dyes methyl yellow and methyl orange were doped in silica thin films by the LPD method and the absorption spectra of the samples were observed. The comparison with the corresponding spectra of the pH indicator dyes in pH-controlled buffer solutions leads to the conclusion that the doped organic dye molecules in the LPD silica solid phase are in an acidic environment equivalent to pH = 3.7. The acidity of the interior of LPD silica is high compared with surface acidity of other silicas such as silica gel. The origin of the high acidity of LPD silica has been attributed to the existence of Si–F bonds inducing an electron-attracting tendency.
Identification of the Absolute Configuration of 1-[4-(Nitrophenylthio)ethyl]ferrocene, -ruthenocene, and -osmocene
Authors: Goto Midori , Yamazaki Yoshimitsu , Honda Kazumasa , Masaki Atsushi
Published: July 2006

(−)-1-[4-(Nitrophenylthio)ethyl]ferrocene, (+)-1-[4-(nitrophenyl)thioethyl]ruthenocene, and (+)-1-[4-(nitrophenylthio)ethyl]osmocene all have the absolute configuration of R. These compounds were prepared by substitution of (R)-(−)-1-(hydroxyethyl)ferrocene, -ruthenocene, and -osmocene with 4-nitrobenzenethiol, showing that the substitution proceeded with retention of configuration.
The Crystal Structures of 2-Aminoperimidine
Authors: Yokoyama Takashi , Masuo Tohru , Akashi Haruo , Zenki Michio
Published: July 2006

The structures of both 2-perimidinylammonium ethyl sulfate (PDAEtSO4) and 2-perimidinylammonium bromide (PDABr) were determined by single-crystal X-ray diffractometry. PDAEtSO4 crystallized in the monoclinic system, space group P21/c, with a = 7.229(2), b = 8.329(1), c = 22.404(1) Å, β = 91.94(1)°, V = 1348.1(3) Å3, Z = 4. PDABr crystallized in the orthorhombic system, space group Pbca with a = 15.441(1), b = 23.877(1), c = 7.468(1) Å, V = 2754.9(4) Å3, Z = 8. The dimer of PDA was observed in both of the crystals. Also, four hydrogen bonds between the PDA ions and the ethyl sulfate ions for PDAEtSO4 were observed. The ions pack in the crystal held together by the dimer of PDA and strong hydrogen bonds between the oxygen atoms of the ethyl sulfate ion and the hydrogen atoms of the amino groups of the PDA ions. The results are discussed along with giving a reason why PDA is an excellent precipitant for the sulfate ion.
The Rhodium(II) Acetate-Catalyzed Reaction of Alkenyl and Alkynyl α-Diazoacetates with Thioketene
Authors: Nakano Hirofumi , Ibata Toshikazu
Published: July 2006

The reaction of allyl α-diazoacetates with di-t-butylthioketene catalyzed by Rh2(OAc)4 gave 4-allyl-2-methylene-1,3-oxathiolan-5-ones through the 1,5-cyclization of a thiocarbonyl ylide intermediate followed by Claisen rearrangement with allene episulfide through the 1,3-cyclization of the intermediate. Other alkenyl and alkynyl diazoacetates also gave similar products through the thiocarbonyl ylide without affording its intramolecular 1,3-dipolar cycloadduct.
Preparation of New Nitrogen-Bridged Heterocycles. 38. Synthesis and Reaction of Dimethyl 6-Thia-3-azatricyclo[5.3.1.03,8]undeca-4,9-diene-7,11-dicarboxylates
Authors: Kakehi Akikazu , Ito Suketaka , Fujita Shuichi
Published: July 2006

The title compounds, dimethyl 6-thia-3-azatricyclo[5.3.1.03,8]undeca-4,9-diene-7,11-dicarboxylates, were smoothly prepared in variable yields by the reactions of some (1-pyridinio)thiocarbonylmethylides with dimethyl acetylenedicarboxylate (DMAD) in chloroform, including various alcohols at room temperature. The mechanistic consideration for these reactions clarified the intervention of primary 1 : 1 zwitterionic intermediates between the ylides and DMAD, which were previously proposed by us, and their traps by alcohol molecules. Some of these dimethyl 6-thia-3-azatricyclo[5.3.1.03,8]undeca-4,9-diene-7,11-dicarboxylates were hydrolyzed by hydrochloric acid to afford dimethyl 7-formyl-4a,5,8,8a-tetrahydro-4H-benzo-1,4-thiazine-8,8a-dicarboxylates or tetramethyl 2,2′-oxydi(6-thia-3-azatricyclo[5.3.1.03,8]undeca-4,9-dien-7,11-dicarboxylate)s.
Reactivities of Stable Rotamers. XXXV. Diazotization of 2-(1,4-Dimethyl-9-triptycyl)-2-methylpropylamine Rotamers
Authors: Oki Michinori , Taguchi Yasushi , Miyasaka Tsutomu , Kitano Mika , Toyota Shinji , Tanaka Toshimasa , Yonemoto Katsumi , Yamamoto Gaku
Published: July 2006

The title amine rotamers were prepared from the corresponding carboxylic acids and were diazotized with isopentyl nitrite in the presence of acetic acid in benzene. The ap rotamer affords, as main products, olefins that are derived by deprotonation after rearrangement of the intervening carbocation and small amounts each of the corresponding acetate and a cyclized product, both of which are derived from the unrearranged cation. By contrast, the olefins are minor products and a cyclized product, which is formally derived by insertion of the intervening cation to a C–H bond of the 1-methyl group before rearrangement, is main in the case of the sc isomer. This cyclic product was synthesized independently. The yield of the corresponding acetate is increased to a considerable extent in the case of the sc relative to the ap. These results in the reaction of the sc are discussed in terms of stabilization of the intervening cation by the C–H bond.
Synthesis of 2-Fluoro Sugar and Its Condensation Reaction with Silylated Thymine
Authors: Niihata Shigeo , Ebata Takashi , Kawakami Hiroshi , Matsushita Hajime
Published: July 2006

2,3-Dideoxy-2-fluoro-d-erythro-pentofuranose was easily prepared from 3-DPA lactone. The condensation reaction between 1-O-acetyl derivative of this sugar and silylated thymine in the presence of TMSOTf proceeded in a poorly stereoselective manner.
Task Scheduling in a Finite-Resource, Reconfigurable Hardware/Software Codesign Environment
Authors: Loo Sin Ming , Wells B. Earl
Published: June 2006

This paper describes how static task-scheduling methods using stochastic search techniques can be applied to digital systems that are composed entirely of reconfigurable hardware. Such reconfigurable hardware is characterized by the property that its low-level logical functionality is not determined at the time of manufacture, but rather that this functionality becomes set only shortly before or during the invocation of the targeted application. The purpose of this paper is to introduce the basic framework for applying static scheduling theory to arbitrarily-structured task systems targeted to be implemented in prefabricated resource-constrained reconfigurable hardware. The paper also describes initial solutions to this heterogeneous task-scheduling problem that combine a distributed list-based scheduling technique with three probabilistic search strategies. The techniques introduced produce detailed task scheduling and high-level hardware configuration information that can serve as inputs to the software and reconfigurable hardware design automation tools used in the hardware/software codesign process.
A Discrete Adjoint Variable Method for Printed-Circuit Board Computer-Aided Design
Authors: Ali Shirook M. , Nikolova Natalia K. , Bakr Mohamed H.
Published: June 2006

We propose an adjoint-variable method for design sensitivity analysis of printed circuits and antennas where allowable perturbations in the design parameters are of a discrete type. We extend previous work on the sensitivity analysis of waveguide structures, where changes in the design parameters are stepwise, on-grid volumetric perturbations. Here, we explore the feasibility of such an approach in the case of printed-circuit board problems (with open boundaries) where perturbations relate to the shapes elements of infinitesimal thickness. We propose a complex-variable formulation of our approximate sensitivity analysis that improves its computational efficiency. The proposed technique offers significant increases in efficiency, accuracy, and convergence when compared to traditional sensitivity-analysis techniques. Its implementation is straightforward. The response and its gradient with respect to all possible design parameters are computed with at most two full-wave analyses—of the original and the adjoint problems. It operates on a fixed discretization grid where perturbations of grid nodes are not needed. We illustrate our technique through the sensitivity analysis of a microstrip line and a probe-fed printed patch antenna as well as the optimization of a printed Yagi antenna array.
Building and Testing Optimized Keyboards for Specific Text Entry
Authors: Francis Gregory , Oxtoby Claire
Published: June 2006

Objective: We explore how to optimally design systems for information input. Background: As computers are introduced into ever more devices with new methods of inputting information, there is a need for specialized systems that are optimally designed for their particular use. Method: The study demonstrates how to use a model of text entry times to build optimized keyboards for specific sets of text. The technique is demonstrated by using Fitts' law to model text entry times. Alphabet letters are assigned to keys in a way that minimizes predicted entry time for the specified set of text. The predicted entry times are validated by an experiment in which two keyboards are optimized for different sets of text. Results: Text entry is faster for the keyboard optimized for that text compared with the keyboard optimized for the other text. Learning to use the keyboards is fairly quick, with significant learning being observed after only one half-hour session. Conclusion: There is a need and an ability to design specialized keyboards for some situations. The study demonstrates that optimization of keyboards can decrease text entry times. Application: This research shows how to design optimized keyboards for many different situations. The approach should be useful for aviation, medical, industrial, and other specialized situations in which normal keyboard designs cannot be used.
Does Crew Resource Management Training Work? An Update, an Extension, and Some Critical Needs
Authors: Salas Eduardo , Wilson Katherine A. , Burke C. Shawn , Wightman Dennis C.
Published: June 2006

Objective: This review provides the state of crew resource management (CRM) training evaluations since the E. Salas, C. S. Burke, C. A. Bowers, and K. A. Wilson (2001) review and extends it to areas beyond aviation cockpits. Some critical evaluation needs in CRM training are also covered. Background: Because of the purported success of CRM training in aviation, other high-consequence domains have begun to implement CRM training for their workforces. However, the true impact of CRM training in aviation and these other domains has yet to be determined. Method: Using D. L. Kirkpatrick's (1976) framework for evaluating training (i.e., reactions, learning, behavior, and organizational impact), we reviewed 28 published accounts of CRM training to determine its effectiveness within aviation, medicine, offshore oil production and maintenance, shipping/maritime, and nuclear power domains. Results: Findings indicate that CRM training generally produced positive reactions from trainees; however, the impact of training on learning and behavioral changes suggest mixed results across and within domains. Furthermore, and as was found by Salas, Burke, et al. in 2001, we cannot ascertain whether CRM has had an impact on the organization's bottom line (i.e., safety). Conclusion: Based on the results, there are several critical needs that the CRM training community must address before CRM training can have the desired impact on safety: a mandate, access to data, and resources. Application: As CRM training expands to organizations beyond aviation, it is critical that its impact be understood such that it can be improved and achieve the intended results.
Learning From Technical Documents: The Role of Intermodal Referring Expressions
Authors: Dupont Vincent , Bestgen Yves
Published: June 2006

Objective: We investigated the impact of two types of intermodal referring expressions on efficiency of instructions for use. Background: User manuals for software or technical devices such as a video recording system frequently combine verbal instructions and illustrations. Much research has shown that the presence of an illustration has a beneficial effect on learning. The present study focuses on a factor that modulates this beneficial effect. The combination of text and an illustration can be effective only if the user integrates the information coming from these two media. This integration depends largely on the intermodal referential expressions, the function of which is to mark explicitly the relations between the text and the illustration. Method: In an experiment (N = 104), we compared the effectiveness of two intermodal referring expressions often used in procedural texts: indexes (numbers introduced in the illustrations and in the instructions to establish cross-references) and icons (visual representations of the components of the device, which are inserted in the verbal instructions). Results: The icons condition led to the most efficient use of the device. Conclusion: This experiment shows that learning from multimedia documents depends on the possibility of effectively connecting the verbal instructions to the illustration. Application: Taking into account the ergonomic properties of the cross-media referring expressions should allow text designers to improve the effectiveness of technical documents.
FGF Signaling Mediates Regeneration of the Differentiating Cerebellum through Repatterning of the Anterior Hindbrain and Reinitiation of Neuronal Migration
Authors: Köster Reinhard W. , Fraser Scott E.
Published: July 2006

To address the regenerative capability of the differentiating hindbrain, we ablated the cerebellum in wild-type and transgenic zebrafish embryos. These larvae showed no obvious locomotive malfunction several days after the ablation. Expression analysis andin vivotime-lapse recording in GFP (green fluorescent protein)-transgenic embryos indicate that cerebellar neuronal cells can regenerate from the remaining anterior hindbrain. The onset of regeneration is accompanied by repatterning within the anterior hindbrain. Inhibition of FGF signaling immediately after cerebellar ablation results in the lack of regenerating cerebellar neuronal cells and the absence of cerebellar structures several days later. Moreover, impaired FGF signaling inhibits the repatterning of the anterior hindbrain and the reexpression of rhombic lip marker genes soon after cerebellar ablation. This demonstrates that the hindbrain is highly plastic in recapitulating early embryonic differentiation mechanisms during regeneration. Moreover, the regenerating system offers a means to uncouple cerebellar differentiation from complex morphogenetic tissue rearrangements.
Corporations and the State in the Global Era: The Case of Seaboard Farms and Texas*
Authors: Bonanno Alessandro , Constance Douglas H.
Published: July 2006

Abstract  Employing the case of the expansion and regulation of hog confined animal feeding operations (CAFO) in Texas combined with the actions of the transnational agri‐food corporation Seaboard Farms, Inc., this paper probes the relationship between the state and corporations in the global era. It specifically investigates the ability of the state to control agri‐food corporations in a context in which the hyper‐mobility of capital has increasingly allowed corporations to by‐pass state regulations and requirements. Salient literature is reviewed by grouping it into three camps: the first views the state as largely controlled by corporations; the second stresses the powers left to the state and the fact that corporations need state assistance to successfully operate in the current global economy; and the third acknowledges the crisis of the nation‐state under globalization but maintains that the state has retained some ability to resist globalization forces. The case study documents the expansion of Seaboard Farms' hog operations in the Panhandle Region of Texas and nearby states and its interaction with local and state governments and agencies. The article indicates that the relationship between transnational corporations and the state is contradictory. Its source rests on the fracture between varying postures maintained by the state and the relatively homogenous behavior of the CAFO corporations. The case also reveals that the state's limited control of corporate actions is facilitated by state strategies; that corporate actions are successful if corporations enlist the cooperation of the state; and the state is able to control resistance and legitimize its actions to its constituencies. These conditions, however, do not prevent the emergence of anti‐corporate resistance at local and state levels. In the search for new forms of socioeconomic development, local residents and their leaders should be aware of corporations' ability to affect state action, state postures that favor corporate designs, and the fact that successful opposition to corporate designs can be, and is, carried out.
Effect of Prone and Supine Position on Sleep, Apneas, and Arousal in Preterm Infants
Authors: Bhat Ravindra Y. , Hannam Simon , Pressler Ronit , Rafferty Gerrard F. , Peacock Janet L. , Greenough Anne
Published: July 2006

OBJECTIVE. Prematurely born compared with term born infants are at increased risk of sudden infant death syndrome, particularly if slept prone. The purpose of this work was to test the hypothesis that preterm infants with or without bronchopulmonary dysplasia being prepared for neonatal unit discharge would sleep longer and have less arousals and more central apneas in the prone position.

METHODS. This was a prospective observational study in a tertiary NICU. Twenty-four infants (14 with bronchopulmonary dysplasia) with a median gestational age of 27 weeks were studied at a median postconceptional age of 37 weeks. Video polysomnographic recordings of 2-channel electroencephalogram, 2-channel electro-oculogram, nasal airflow, chest and abdominal wall movements, limb movements, electrocardiogram, and oxygen saturation were made in the supine and prone positions, each position maintained for 3 hours. The duration of sleep, sleep efficiency (total sleep time/total recording time), and number and type of apneas, arousals, and awakenings were recorded.

RESULTS. Overall, in the prone position, infants slept longer, had greater sleep efficiency (89.5% vs 72.5%), and had more central apneas (median: 5.6 vs 2.2), but fewer obstructive apneas (0.5 vs 0.9). The infants had more awakenings (9.7 vs 3.5) and arousals per hour (13.6 vs 9.0) when supine. There were similar findings in the bronchopulmonary dysplasia infants.

CONCLUSIONS. Very prematurely born infants studied before neonatal unit discharge sleep more efficiently with fewer arousals and more central apneas in the prone position, emphasizing the importance of recommending supine sleeping after neonatal unit discharge for prematurely born infants.
The Contribution of Hemolysis to Early Jaundice in Normal Newborns
Authors: Maisels M. Jeffrey , Kring Elizabeth
Published: July 2006

OBJECTIVE. Neonatal jaundice is the result of an imbalance between bilirubin production and elimination, and our objective was to clarify the contribution of an increase in bilirubin production to hyperbilirubinemia in newborns.

METHODS. We measured the end-tidal carbon monoxide concentration corrected for ambient carbon monoxide concentration in 108 jaundiced newborns (total serum bilirubin level >75th percentile) and 164 control newborns in our well-infant nursery, for the first 4 days after birth.

RESULTS. Mean end-tidal carbon monoxide levels decreased in the control infants in the first 4 days but increased in the hyperbilirubinemic group. The differences between the jaundiced and nonjaundiced infants were statistically significant on all days.

CONCLUSIONS. Before hospital discharge, most infants with bilirubin levels >75th percentile are producing significantly more bilirubin than those with lower bilirubin levels. Because the ability of newborns to conjugate bilirubin is significantly impaired in the first few days, even a small increase in the rate of production can contribute to the development of hyperbilirubinemia. These data suggest that increased heme catabolism is an important mechanism responsible for hyperbilirubinemia in the first 4 days after birth.
Interfacial-shear strength of the perfluorocyclobutane films on silicon
Authors: Boddapati Srinivasa Rao , Ma Hong , Bordia Rajendra K. , Jen Alex K-Y.
Published: June 2006

The debonding behavior of perfluorocyclobutane (PFCB) films on silicon (Si) has been investigated using Vickers indentation as a function of cure temperature and film thickness. PFCB films on Si were processed by spin coating (1–4 μm) and solution casting (20–60 μm). The interfacial shear strength of solution-cast PFCB films was independent of film thickness. The interfacial shear strength increased with cure temperature. The PFCB/Si cured at 225 °C exhibited interfacial shear strength of 123 MPa, and the strength increased to 163 MPa when the cure temperature was raised to 275 °C. The increase in interfacial-shear strength with temperature has been attributed to the increase in the density of bonds between PFCB and Si due to an increase in the density of crosslinks. Spin-coated films exhibited cracking due to the penetration of the indenter into the substrate, and the extent of cracking increased with the load.
Development of microstructure in Tl-2212 thin films and possible influence on microwave surface resistance values
Authors: Speller S.C. , Wu H. , Rek Z.U. , Bilello J.C. , Grovenor C.R.M.
Published: June 2006

The microstructures of Tl2Ba2Ca1Cu2O8 (Tl-2212) films are very strongly influenced by the processing parameters used to synthesize the superconducting phase and also control the microwave surface resistance values that are of key importance in the application of these materials in high-frequency devices. We report here on detailed studies of how the mesotexture of Tl-2212 films develops during synthesis at 820 and 855 °C. Our key observation is that the microstructure, and hence the superconducting properties, are controlled by the mechanism by which stress is relieved in the films and that apparently perfectly epitaxial films do not have the best microwave performance because in these samples the stress is relieved by macroscopic defects rather than local, low-angle grain misorientations.
Solvothermal synthesis of carbon nitrogen nanotubes and nanofibers
Authors: Mu Tiancheng , Huang Jun , Liu Zhimin , Li Zhonghao , Han Buxing
Published: June 2006

Carbon nitrogen nanotubes and nanofibers with controlled nitrogen concentration have been prepared by reaction of cyanuric chloride and hexachlorobenzene (HCB) with sodium metal at 250 °C in cyclohexane. Electron microscopy and spectroscopic analysis were used to characterize the products. The total yields of the tubes and fibers decrease as the ratio of cyanuric chloride to HCB increases, and nitrogen content in the products could be controlled by the ratio. The nanostructures depended strongly on the nitrogen content. Lower nitrogen content was favorable for producing linear products.
Superior glass-forming ability of CuZr alloys from minor additions
Authors: Yu P. , Bai H.Y. , Wang W.H.
Published: June 2006

We report a novel phenomenon in which minor element additions (∼1 at.%) can dramatically enhance the glass-forming ability (GFA) of CuZr(Al) metallic alloy, which can be cast into glasses with large cross-section sizes using a conventional casting method. The minor additions cause the liquidus temperature Tl to decrease from 1219 (for Cu50Zr50) to 1139 K [for (Cu50Zr50)92Al7Gd1], and the reduced glass transition temperature Trg (=Tg/Tl) of the alloys increases from 0.550 (for Cu50Zr50) to 0.613 [for (Cu50Zr50)92Al7Gd1]. The mechanism involved in the achievement of the superior GFA is explained by the stronger tendency of short-range ordering in the stronger microalloyed alloys as well as the thermodynamic and kinetic aspects.
Interfacial reactions in the Sn–9Zn–(xCu)/Cu and Sn–9Zn–(xCu)/Ni couples
Authors: Chou Chin-yi , Chen Sinn-wen , Chang Yee-shyi
Published: June 2006

Sn–Zn-based alloys are promising low melting-point Pb-free solders, and it has been reported that their wetting properties and oxidation resistance can be improved with the addition of Cu. The interfacial reactions in the Sn–9 wt% Zn–xCu/Cu couples at 250 °C and Sn–9 wt% Zn–xCu/Ni at 280 °C were examined in this study. A thick γ–Cu5Zn8 phase layer and a very thin β′–CuZn phase layer were formed in both the Sn–9 wt% Zn/Cu and the Sn–9 wt% Zn–1 wt% Cu/Cu couples. The γ–Ni5Zn21 phase layer was formed in both the Sn–9 wt% Zn/Ni and Sn–9 wt% Zn–1 wt% Cu/Ni couples. With longer reaction time, the δ–Ni3Sn4 phase were formed in the Sn–9 wt% Zn/Ni couple as well. In both the Cu and Ni couples, the Zn-containing γ phases were uniform and planar and were the dominant reaction products. However, when the Cu content of the Sn–9 wt% Zn–xCu solders was 10 wt%, the interfacial reaction product becomes the η–Cu6Sn5 phase in both the Cu and Ni couples.
Photoluminescence of Eu3+ activated Ba2SnO4 under ultraviolet–vacuum ultraviolet excitation
Authors: Gao Hui , Wang Yuhua
Published: June 2006

A novel red emitting phosphor, Eu3+-doped Ba2SnO4, has been synthesized by solid-state reaction. Photoluminescence (PL) excitation spectrum of Ba2Sn0.925Eu0.075O4 shows the strongest broad band from 220 to 280 nm due to the charge transfer (CT) band of Eu3+–O2−, and the band centered at 180 nm could be caused by the CT band of Ba2+–O2−. The band (110–130 nm) could be attributed to SnO68− octahedron band absorption. It is found that under 254 nm excitation, Ba2Sn1−xEuxO4 (0.025 ≤ x ≤ 0.125) exhibits a strong emission at around 592 nm, and with the increase in Eu3+, the phosphors present orange to red luminescence due to the decreasing of the site symmetry of Eu3+. The maximum PL intensity has been obtained for 7.5 mol% concentration of Eu3+ in Ba2SnO4. On the other hand, under 147 nm excitation, the phosphors do not emit effectively because of inefficient absorption in vacuum ultraviolet (VUV) region.
Interstitial Fluorescence Spectroscopy in the Human Prostate During Motexafin Lutetium‐Mediated Photodynamic Therapy
Authors: Finlay Jarod C. , Zhu Timothy C. , Dimofte Andreea , Stripp Diana , Malkowicz S. Bruce , Busch Theresa M. , Hahn Stephen M.
Published: June 2006

The in vivo fluorescence emission from human prostates was measured before and after motexafin lutetium (MLu)‐mediated photodynamic therapy (PDT). A single side‐firing optical fiber was used for both the delivery of 465 nm light‐emitting diode excitation light and the collection of emitted fluorescence. It was placed interstitially within the prostate via a closed transparent plastic catheter. Fitting of the collected fluorescence emission spectra using the known fluorescence spectrum of 1 mg/kg MLu in an intralipid phantom yields a quantitative measure of the local MLu concentration. We found that an additional correction factor is needed to account for the reduction of the MLu fluorescence intensity measured in vivo due to strong optical absorption in the prostate. We have adopted an empirical correction formula given by C = (3.1 cm−1/μ′s) exp (μeff· 0.97 cm), which ranges from approximately 3 to 16, with a mean of 9.3 ± 4.8. Using a computer‐controlled step motor to move the probe incrementally along parallel tracks within the prostate we can determine one‐dimensional profiles of the MLu concentration. The absolute MLu concentration and the shape of its distribution are confirmed by ex vivo assay and by diffuse absorption measurements, respectively. We find significant heterogeneity in photosensitizer concentration within and among five patients. These variations occur over large enough spatial scales compared with the sampling volume of the fluorescence emission that mapping the distribution in three dimensions is possible.
Organization and Financing of Alcohol and Substance Abuse Programs for American Indians and Alaska Natives
Authors: McFarland Bentson H. , Gabriel Roy M. , Bigelow Douglas A. , Walker R. Dale
Published: June 2006

Objectives. Although American Indians and Alaska Natives have high rates of substance abuse, few data about treatment services for this population are available. We used national data from 1997–2002 to describe recent trends in organizational and financial arrangements.

Methods. Using data from the Indian Health Service (IHS), the Substance Abuse and Mental Health Services Administration, the National Institute on Alcohol Abuse and Alcoholism, the Henry J. Kaiser Family Foundation, and the Census Bureau, we estimated the number of American Indians served by substance abuse treatment programs that apparently are unaffiliated with either the IHS or tribal governments. We compared expected and observed IHS expenditures.

Results. Half of the American Indians and Alaska Natives treated for substance abuse were served by programs (chiefly in urban areas) apparently unaffiliated with the IHS or tribal governments. IHS substance abuse expenditures were roughly what we expected. Medicaid participation by tribal programs was not universal.

Conclusions. Many Native people with substance abuse problems are served by programs unaffiliated with the IHS. Medicaid may be key to expanding needed resources.
Educational Inequalities in Initiation, Cessation, and Prevalence of Smoking Among 3 Italian Birth Cohorts
Authors: Federico Bruno , Costa Giuseppe , Kunst Anton E.
Published: June 2006

Objectives. We examined socioeconomic inequalities in initiation and cessation rates of smoking and the resultant inequality in smoking prevalence among 3 consecutive Italian birth cohorts.

Methods. We used data from the 1999–2000 Italian National Health Interview Survey, which included 28958 men and 29769 women who were born between 1940 and 1969. The association between smoking variables and level of education was assessed with logistic regression and life table analyses.

Results. Inequalities in the lifetime prevalence of smoking increased across the 3 birth cohorts in Italy. At age 40, lower-educated persons in the youngest cohort reported on average 1 to 5 years of additional exposure to regular smoking compared with higher-educated persons. Inequalities in smoking prevalence increased among both men and women because of widening inequalities in initiation rates. Among women, growing inequalities in cessation rates also played a role.

Conclusions. The relative contribution of initiation and cessation to socioeconomic inequalities in smoking rates varied by both gender and birth cohort. For the youngest birth cohort, policies that address inequalities in smoking should focus on both initiation and cessation.
Sustainability of Public Health Programs: The Example of Tobacco Treatment Services in Massachusetts
Authors: LaPelle Nancy R. , Zapka Jane , Ockene Judith K.
Published: June 2006

Sustaining important public or grant-funded services after initial funding is terminated is a major public health challenge. We investigated whether tobacco treatment services previously funded within a statewide tobacco control initiative could be sustained after state funding was terminated abruptly. We found that 2 key strategies—redefining the scope of services being offered and creative use of resources—were factors that determined whether some community agencies were able to sustain services at a much higher level than others after funding was discontinued. Understanding these strategies and developing them at a time when program funding is not being threatened is likely to increase program sustainability.
A Comparison of the Health and Mental Health Status of Homeless Mothers in Worcester, Mass: 1993 and 2003
Authors: Weinreb Linda F. , Buckner John C. , Williams Valerie , Nicholson Joanne
Published: June 2006

Objectives. We assessed background characteristics, health status, and prevalence rates of mental health disorders in 2 studies of homeless mothers conducted in Worcester, Mass, one in 1993 and the other in 2003.

Methods. We compared the women taking part in the 2 studies, which involved similar methodologies, on the key variables of interest over time.

Results. Homeless families taking part in the 2003 study were poorer than those taking part in the 1993 study, and female heads of household in that study reported more physical health limitations, major depressive illness, and posttraumatic stress disorder.

Conclusion. Data from 2003 suggest that the characteristics of homeless mothers changed over the 10-year period assessed. Service providers and shelter staff may need to refine services so that they are responsive to these changing needs.
Cessation Among Smokers of “Light” Cigarettes: Results From the 2000 National Health Interview Survey
Authors: Tindle Hilary A. , Rigotti Nancy A. , Davis Roger B. , Barbeau Elizabeth M. , Kawachi Ichiro , Shiffman Saul
Published: June 2006

Objectives. A large proportion of smokers erroneously believe that low-nicotine/low-tar cigarettes, also called “light cigarettes” or “lights,” reduce health risks and are a rational alternative to smoking cessation. However, the availability of light cigarettes may deter smoking cessation.

Methods. We analyzed the 32374 responses to the US 2000 National Health Interview Survey. Current and former smokers (“ever-smokers”) were asked if they had ever used a lower tar and nicotine cigarette to reduce health risks. Multivariable logistic regression identified determinants of lights use and smoking cessation. Results were weighted to reflect the national population.

Results. Of 12285 ever-smokers, 37% (N=4414) reported having used light cigarettes to reduce health risks. Current abstinence was less often reported by ever-smokers who had previously used light cigarettes than by ever-smokers who had never used lights (37% vs 53%, P<.01). Adjusted odds of cessation among ever-smokers who had used light cigarettes relative to those who had never used lights were reduced by 54% (adjusted odds ratio=0.46, 95% confidence interval=0.41, 0.51).

Conclusions. Use of light cigarettes was common and was associated with lower odds of current smoking cessation, validating the concern that smokers may use lights as an alternative to cessation.
‘MSN was the Next Big Thing after Beanie Babies’: Children's Virtual Experiences as an Interface to Their Identities and Their Everyday Lives
Authors: Thomas Angela
Published: June 2006

In this article the author explores the seamlessness between children's online and offline worlds. For children, there is no dichotomy of online and offline, or virtual and real; the digital is so much intertwined into their lives and psyche that the one is entirely enmeshed with the other. Despite early research pointing to the differences that mark the virtual as a space of ‘otherness’, the author suggests that the fabric of children's everyday lives knows no such distinct demarcation, and that what they do in their virtual worlds significantly affects how they connect to society. Moreover, through the virtual, children are simultaneously engaging in acts of self-reflection, self-fashioning and identity formation. Using data from a longitudinal ethnographic study of children online, the author illuminates a number of case studies which support this argument. She does this by using narrative accounts based on extensive interviews with the children.
‘Getting the Reader on Side’: Exploring Adolescent Online Political Discourse
Authors: Humphrey Sally
Published: June 2006

In recent years there has been growing awareness of the need to support primary and secondary students in developing competencies for active and participatory citizenship. Among the essential competencies identified in a recent study of politically active teachers was the ability to expand ideas into arguments. This article reports on the early stages of a study which aims to describe key semiotic resources used by adolescents engaged in political or social activism. The study is first contextualised within current literacy, education and youth studies research. Resources used by one young social activist to argue a case and raise awareness on her weblog are then analysed and the implications for e-learning discussed.
Cybergirls: Negotiating Social Identities on Cybersites
Authors: Guzzetti Barbara J.
Published: June 2006

Cyberspace has been regarded as an ideal site for adolescents' identity exploration since it is socially mediated. Liberal cyberfeminists argue that virtual spaces promote gender equality, fluidity, and unity through body-free interactions. This study investigated the cybersites frequented by two adolescent girls who eschewed typical representations of gender in their online and offline worlds. The purpose of the study was to describe how these young women constructed and consumed dynamic websites in their formations and representations of their identities as ‘Do-It-Yourselfers’ and punk rock fans. In situ observations, online interviews, and screen printouts were collected and analysed to describe how these textual creations in cyberspace facilitated or impeded identity construction. The cases illustrate how these adolescent girls made use of websites for affirmation, reflection, reinforcement, and negotiation in the process of staking claims about their selves, and demonstrate how the online environment may provide safe spaces for girls that are not found offline.
Language, Culture, and Identity in Online Fanfiction
Authors: Black Rebecca W.
Published: June 2006

This article draws on constructs in second-language acquisition, literacy, cultural, and media studies as theoretical bases for examining how networked technologies and fan culture provide a young English language learner (ELL) with a site for developing her English language and writing skills. During this process, she also develops an online identity as a popular, multiliterate writer. To understand how this happens, the notion of identity is explored as a fluid construct that shifts over time with this ELL's long-term participation in a fan community. Popular and fan culture are also examined as points of affiliation and as dialogic resources that she appropriates, both in her writing and in her interactions with other fans. In so doing, the article demonstrates how popular culture and technology converge to provide a context in which this adolescent ELL is able to develop a powerful, transcultural identity, discursively constructed through the different cultural perspectives and literacies that she and other fans from across the globe bring to this space.
Categories, Gender and Online Community
Authors: Marshall Jonathan Paul
Published: June 2006

This article presents a sketch for a theory of the rhetorics involved in categorisation and the creation of culture in online communities. Persuasion, or shaping perceptions of the world, is never incidental to social life, but living online necessarily involves persuasion as it is difficult to bring force to bear, although people can be temporarily excluded from different groups to different degrees, and the modality of persuasion may be influenced by the structures of communication in play. Communication almost always involves an attempted act of power aiming to produce a response in another. It is argued that linguistic categories, especially self-identity categories, are to some extent flexible, and that they exist in connection and contrast with other categories. The meaning of categories depends upon the ways they are framed (frames can also be categories), and framing and category content can be the subject of argument. Among the most important ways of framing online by Westerners are by space, public/private, authenticity, gender and community. The rest of the article explores the nature of online communication and power; how gender is used as a category; the kinds of effects that this categorisation has had; and how this category becomes salient within the framework of people making a ‘community’ on the Cybermind mailing list.