Search

A hole in the center of the aluminum (Al) alloy was processed to compensate for the mechanical properties of resistance welded joints of the carbon fiber reinforced epoxy resin matrix (CF/Epoxy) laminate and Al alloy for solving the problem of poor bonding quality in the center of the joint due to uneven temperature distribution in the resistance welding process. The resistance welded lap configuration of the upper Al and the lower laminate was employed, and through holes with a different diameter (dh) were prefabricated on the upper Al alloy plates. The molten polyetherimide (PEI) resin was bonded to the surfaces of the samples on both sides under the action of Joule heat, and the excess PEI resin filled the prefabricated through-hole of the Al alloy plate under pressure and realized the jointing of the 6063Al alloy plate and the CF/Epoxy laminate. The micro-morphology of the welded interface was characterized by scanning electron microscopy (SEM), and the heat distribution of the sample was simulated using COMSOL. The tensile shear force of the joint was tested, which rises with an increase of dh. The failure interface was analyzed in detail, which showed a strong correlation with dh. [ABSTRACT FROM AUTHOR]

This study explores the effect of different graphene contents on the mechanical behaviour, tensile and flexural properties, and the electrochemical performance of cross-layered glass-reinforced aluminium (GLARE) laminates. Results show that the mechanical properties of GLARE with different graphene contents are similar but not identical. The mass fraction of graphene (0 wt.%–1.0 wt.%) is calculated from the total mass of adhesive. As the graphene content increases (0 wt.%–1.0 wt.%), flexural strength peaks in the presence of 0.5 wt.% graphene, but tensile strength continues to increase. When the graphene mass ratio is 1.0 wt.%, the maximum tensile strength is 245.45 MPa. When the graphene mass ratio is 0.5 wt.%, interlaminar shear strength and flexural strength are 19.06 and 260.22 MPa, respectively, which correspond to different span–thickness ratios of 8/1 and 32/1. This graphene mass ratio indicates the best three-point flexural performance of graphene-reinforced GLARE. This study further explains the enhancement mechanism through fracture surface observation. Graphene with a mass ratio of 0.5 wt.% maximises the flexural strength whilst maintaining a strong GLARE electrochemical performance. At scanning speeds of 40, 80, and 100 mV/s, the specific capacitance values are 1.76, 2.47, and 2.88 F/g, respectively. According to quantum tunnelling theory, graphene can form a conductive network when it is dispersed in a resin matrix. This theory reveals the reason why 0.5 wt.% graphene platelet-modified GLARE has good electrochemical properties. [ABSTRACT FROM AUTHOR]

A breakable model of ballast particle is developed by using the Discrete Element Method (DEM). A method of modelling the Under Sleeper Pad (USP) by using 'elastic rods' is proposed. After integrating the model of the sleeper, USP and ballast, the dynamic train load is applied to analyze the dynamic response of the ballast bed. The following results can be drawn: (1) The USP increases the contact area between the sleeper and ballast particles, and effectively reduces the contact stress. Comparing the track using USP to the traditional ballast track, maximum stress in ballast is reduced by 26.10%, and the average stress is reduced by 3.22%. (2) The breakage of ballast particles in the upper part the ballast bed of the traditional ballast track is mostly overall damage, while the breakage in the lower part mainly occurs at the sharp corners. Using the USP can mitigate the overall breakage at the upper part. (3) The USP can reduce both the tensile failure and shear failure of ballast breakage compared to the traditional ballast track. (4) When using the USP, the ballast settlement is faster to be stable and with a smaller value under long-term train loads. [ABSTRACT FROM AUTHOR]

The total ionizing dose response of 22nm bulk silicon nFinFETs with different bias conditions is investigated using 60Co γ -rays. The experimental results show that constant voltage stress (CVS) has an important effect on the electrical parameters of the devices. After the CVS experiment, the threshold voltage of the device shifts positively and the on-state current decreases. The threshold voltage of devices irradiated under ON bias and ON bias after CVS shifts positively, and the ON bias device has shown large degradation. The threshold voltages of devices irradiated under ALL0 bias and TG bias shift negatively. The on-state current of the device increases with the accumulation of irradiation dose. There is no significant change in the subthreshold swing and 1 / f noise power spectrum of the device after irradiation, indicating that the irradiation produces fewer interface traps and border traps. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the safety and clinical efficacy of mini-laparoscopic pyeloplasty in treating ureteropelvic junction obstruction (UPJO) in infants. We retrospectively analysed the clinical data of 66 infants with UPJO from January 2013 to August 2018 at our hospital. They were divided into the laparoscopic surgery group (group A) and the open surgery group (group B), depending on the surgical method. The bleeding volume, analgesia duration, postoperative hospitalization duration, and incision length in group A were significantly less than those in group B (p <.05). The incidence of incision dehiscence was 0% in group A and 11.7% in group B (p =.045). At the postoperative follow-up, the incidence of anastomotic stenosis was 6.2% in group A and 5.9% in group B (p =.719). The anteroposterior diameter and glomerular filtration rate were significantly improved at the one-year follow-up, but there was no significant difference between the groups (p >.05). Mini-laparoscopic pyeloplasty to treat UPJO in infants has the same early clinical efficacy and safety as open surgery, and this procedure has the advantages of fewer incisions, less pain, quicker recovery, and better cosmetic outcomes. [ABSTRACT FROM AUTHOR]

This study investigated on people's two-stage iterative trust building process (the initial trust stage and the iteration from feedback stage) with AI partners, and made comparisons with human partners in the aspects of investment behavior, emotional arousal and neuro activities. The experiment was designed using repeated trust games and the investment amount was transformed into the initial trust, the feedback from the partner and the final trust. Comparisons of behavior were conducted by regression analysis. The results showed that the initial trust for AI had stronger influence on the final trust than human partners, while the feedback from human during interaction had stronger influence than the feedback from AI. By emotion scales, it was found that the arousal of participants' positive emotions was more significant when interacting with human than with AI, and the emotional arousal (both positive and negative ones) had stronger correlation with the feedback from human than from AI.. The findings indicated a stronger influence of feedback from human partners on decision making and emotional arousal than from AI partners. The fNIRS results also showed that people's neuro activities in the PFC were stronger when making investment decisions towards human than AI partners. [ABSTRACT FROM AUTHOR]

AbstractFibre reinforced metal laminates (FMLs) are widely used in various fields due to their excellent properties. However, the weak interlayer properties of FMLs limit their applications. In this paper, the interlayer properties of FMLs are enhanced by anodising the 2024-T3 aluminium alloy layer in FMLs or by epoxy matrix modification of graphene nanoplatelets (GNPs). The effect of both synergistic impacts on the interlayer properties of most FMLs is investigated. The FMLs were manufactured using the wet lay-up technique using 2024-T3 aluminium alloy, E51 epoxy and EW100 glass fibre. The results showed that the type I fracture toughness, tensile strength, flexural strength, interlayer shear strength and single layer shear strength of FMLs after anodic oxidation treatment were increased by 406.4%, 10.3%, 18.3%, 42.6% and 28.3%, respectively, compared with those of pure FMLs. The type I fracture toughness, tensile strength, flexural strength, interlayer shear strength and single layer shear strength of the GNPs-modified FMLs matrix were increased by 280.4%, 3.7%, 6.8%, 34.5% and 19.1%, respectively, compared with those of pure FMLs. Moreover, the synergistic effect of FMLs indicates that the simultaneous anodic oxidation and GNPs modification of FMLs can lead to the best mechanical properties of FMLs. Microscopic images and schematics illustrate the toughening mechanism of anodising and GNPs, including the enhancement of aluminium/resin interface and fibre/resin interface and the enhancement of resin matrix properties. [ABSTRACT FROM AUTHOR]

The present study was conducted to interpret the effect of magnetic field on water pH and calcium form, and evaluate semen quality, fertility and hatchability rates of Fayoumi chickens receiving magnetized drinking water (MDW). A total of 180 Fayoumi chickens (20 roosters + 160 hens), 54 weeks of age, were divided into two groups. The first group served as control, which received regular drinking water, and the second group was treated with MDW. Semen was collected twice (at day 15 and day 30 of the experiment) to determine semen quality. Fertility and hatchability were determined in two patches of hatching eggs through 1–15 and 16–30 days of the experiment. Results showed that the roosters of MDW group had higher live sperm and sperm motility ratios than those of the control group throughout the experimental period (1–30 days). The abnormal sperm ratio and methylene blue reaction time of MDW-received roosters were significantly lower than those of control roosters. Fertility and hatchability percentages of MDW group were greater compared to those of regular drinking water. Conclusively, alterations in the physiochemical characteristics of MDW and the calcium form can play a role in improving semen quality, fertility, and hatchability percentages during the late laying phase. [ABSTRACT FROM AUTHOR]

This paper concerns an event-triggered control for uncertain linear systems with process time-varying delays. An adaptive event trigger (AET) is employed for reducing the data transmission amount from the sensor to the controller. Because a positive constant and a positive variable are simultaneously involved in the AET, the AET condition may be difficult to be violated and the data transmission amount may be reduced. A discrete-time feedback control law is employed to guarantee the uniformly ultimately bounded (UUB) of the closed-loop systems. If the gain matrix of the time-delayed state is compromised with the sufficient stability condition, the desired stability can be always achieved regardless of the time-varying delays. In addition, the bound region can be specified by regulating the threshold of the AET. It is proved that the unwanted Zeno phenomena is naturally excluded since the minimal event-triggered time-interval of the AET is a positive real number. Furthermore, the maximal event-triggered time interval can also be quantitatively approximated. A numerical example is provided to demonstrate the effectiveness of the proposed method, and the influences of the AET threshold and time delay are discussed as well. [ABSTRACT FROM AUTHOR]

The engineering purpose of designing resistant structures in seismic areas goes through the modeling of the earthquake ground motion. To design complex earthquake-resistant structures, above all if the structural non-linearities must be considered, dynamic analysis of the response of the structure is highly recommended instead of the response spectrum analysis. Therefore, the need to generate artificial accelerograms for structural design arises. This paper proposes a stochastic procedure that, based on the seismological point-source model, allows to generate artificial accelerograms. Therefore, the artificial accelerogram generated incorporates the "source," "path" and "site" characteristics. For each term of the seismological model, a corresponding best approximating filter transfer function has been given. Therefore, a new quadruple-filter system has been derived. The proposed approach is used to generate various earthquake records that occurred in Italy. The outcomes of the numerical examples demonstrate the suitability of the proposed study. [ABSTRACT FROM AUTHOR]

Over the last decade, tourism academia has been increasingly characterised as working in a knowledge domain that is sociologically framed. To date, however, there has been no explicit consideration in the literature as to whether and how an academic's spiritual and/ or religious beliefs should influence their engagement with knowledge formation. Drawing on Barkathunnisha et al.'s article "Towards a spirituality-based platform in tourism higher education" published in Current Issues in Tourism that proposed the notion of the 7th platform of tourism knowledge based on spirituality and the underlying four pillars – a spirit of knowing; a spirit of doing; a spirit of being; and a spirit of becoming – this exploratory paper will seek to propose some preliminary thoughts on some of the challenges and opportunities that a belief in spirituality and religion might have for tourism academia. Drawing on autobiographical insights from the author's own Christian faith, the paper concludes by discussing issues that the tourism academy will have to face in order to find ways to bring such a spiritual/ religious perspective into the formulation of tourism knowledge. [ABSTRACT FROM AUTHOR]

This article investigates the polynomial integral input-to-state stability in mean square (ms-PIISS) and polynomial (t + 1) ℵ -weighted integral input-to-state stability in mean square ( (t + 1) ℵ -weighted ms-PIISS) for pantograph stochastic systems. The above stability is achieved through dynamic event-triggered mechanism and static event-triggered mechanism. To avert Zeno behaviour in each sample path, our event-triggered mechanisms (ETMs) force a pause time after each successful execution, which will lead to intermittent detection of system status, thus greatly saving communication resources. One utilises the Hanalay-type inequality to obtain the less conservative stability criterion. In addition, a collaborative design method of ETM and linear controller is proposed. Ultimately, an paraphrastic example is shown to indicate the availability of the mentioned collaborative design process. [ABSTRACT FROM AUTHOR]

Hurdle technology was applied to lucuma fruit pulp by slight reduction of water activity (aW) and pH. The original aW (0.97) and pH (5.2) of the pulp were reduced to 0.92 and 0.90, and to 4.7 and 4.4, respectively. Growth of spoilage microorganisms (total viable count (TVC), yeasts, molds, coliforms, and Escherichia coli) was monitored during the 90-day refrigerated storage. The combined reduction of aW and pH of lucuma pulp kept TVC under control and caused a reduction of yeast population. However, individual reduction of aW or pH was not as effective on TVC and yeast. On the other hand, molds and coliforms were undetected after 60 and 90 days of storage in all lucuma samples, respectively. In conclusion, a microbiologically stable lucuma pulp, under refrigerated conditions, could be obtained by reducing its aW to at least 0.92, and simultaneously reducing its pH to at least 4.7. [ABSTRACT FROM AUTHOR]

In this paper, state space of a time-homogeneous Markov process is split into several ordered subspaces. Then, there are three kinds of transitions between states—transitions from a higher-order subspace to a lower-order subspace, transitions within the same subspace, and transitions from a lower-order subspace to a higher-order subspace. Considering time interval omission problem and first passage time considered, we define some related counting processes for the Markov process and discuss their associated probabilities, expectations and generating functions by using Laplace transform. The main results are presented in matrix forms. The relationships among counting processes and their special cases are also discussed briefly. Some simple numerical examples are presented to illustrate the established results. These results will be useful in different problems arising in reliability, economics and social science fields. [ABSTRACT FROM AUTHOR]

Different from the condition rating system for bridges, the criticality and vulnerability rating system for long-span suspension bridges is used to determine the time intervals for routine general inspection of key structural components of the bridge. In consideration of uncertainties involved in the current rating system for long-span suspension bridges, this study presents a cloud-based analytic hierarchical process (C-AHP) rating system to determine inspection intervals. A three-level hierarchical structure is first introduced in terms of criticality and vulnerability, and the relative weights for the hierarchical structure are determined by AHP. The Gaussian cloud model is then introduced to the AHP rating system to form a C-AHP rating system for long-span suspension bridges. Finally, the feasibility and effectiveness of the proposed C-AHP rating system are calibrated by using the Tsing Ma Bridge in Hong Kong as a case study. The case study results show that the proposed C-AHP rating system could take into consideration not only fuzziness but also randomness in the AHP rating system and provide stricter time intervals than the F-AHP rating system for routine general inspection of long-span suspension bridges. [ABSTRACT FROM AUTHOR]

We investigate the equilibrium behavioral strategy for a defined contribution (DC) pension plan during the accumulation phase in this paper. We adopt a state-dependent function to describe the risk tolerance attitude of a mean-variance (MV) investor, which is a piecewise linear function of the current wealth level with the reference point being the discounted investment target. Meanwhile, the stochastic labor income is taken into account, whose risk sources arise from both financial and non-financial markets. The extended Hamilton-Jacobi-Bellman (HJB) system of equations for our problem is presented. Explicit expressions for the suboptimal equilibrium behavioral strategy and its corresponding equilibrium value function are obtained in the suboptimal sense by the stochastic control technique. We find that the suboptimal equilibrium behavioral strategy takes a piecewise linear feedback form of the current wealth level with respect to the discounted investment target, and it also depends on the current labor income. Finally, some numerical analyses are provided to illustrate the effects of model parameters on the suboptimal equilibrium behavioral strategy and the variance-expectation curve, which shed light on our theoretical results. [ABSTRACT FROM AUTHOR]

After an earthquake, a track-bridge system may suffer damage and residual deformation, posing a threat for trains passing over a bridge. However, since railway transportation is an important channel for disaster relief, the timely passage of trains is of great significance for the transportation of materials and personnel. In the past, subjective and experience-based judgments were made on whether a train can pass over an earthquake-damaged bridge, and no relevant numerical calculations were carried out. Therefore, a strategy for the evaluation of train performance when passing over existing bridges after earthquakes was proposed. The strategy considers the randomness of track irregularity, and evaluates the running safety performance (RSP) and running comfort performance (RCP) of trains passing over existing bridges from the perspective of probability. The probability law of a lateral residual bridge deformation influence on the RSP and RCP after an earthquake was revealed. Finally, the maximum train passing speed which ensures the RSP was recommended. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Benzodiazepines are an important class of heterocyclic compounds in organic chemistry. They are known for their diverse physicochemical and biological properties. Some benzodiazepine derivates are well-known drugs with diverse and strong pharmacophoric moiety. An immense number of pharmacological research on benzodiazepine heterocycles and their derivatives have recently been conducted to explore its numerous pharmacological potentials as better therapeutic candidates for the treatment of various disorders, benzodiazepines, however, are one of the main sources of interest for many medicinal chemists. Researchers are drawn to the benzodiazepine nucleus for the synthesis of new drugs because of its potent pharmacophoric moiety and ring shape. Due to the emergence of new pathogenic strains' resistance to the presently available drugs, there has been a constant demand for more effective and selective drugs. Benzodiazepine moiety has all the desired qualities for selective drug candidates used as useful therapeutic agents. Given the importance of benzodiazepine moiety, the current review aims to assess benzodiazepine syntheses as well as their pharmacological properties for potential molecular targets in therapeutic development. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper concerns to an event-triggered control for switching linear systems. For reducing the data transmission amount of the communication network from sensor to controller, a switching-mode independent dynamic event-trigger (DET) is constructed wherein a positive constant and a positive auxiliary variable are simultaneously involved. Based on the received discrete-time state measurements, a mode-dependent feedback control law is proposed. Given some prior activation probabilities of switching signal, an average dwell time (ADT) based controller designed method is presented. It is proved that the closed-loop system achieves Zeno-free mean square bounded exponentially stable (MSBES). Significantly, the minimal event-triggered interval can be accurately given while the maximal event-triggered interval can be approximated. Numerical examples are provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Manufacturing is fundamental to the real economy. Given the central role of cost management in the manufacturing industry, we study the role of people in firms' cost management. We find that manufacturing background CEOs significantly decrease cost stickiness. The results can be explained by a manufacturing background CEO's focus on corporate cost management and his superior ability to choose flexible production to accelerate inventory flow and mitigate the bullwhip effect. We also show that the impact of manufacturing background CEOs on cost stickiness is more prominent in firms with high demand uncertainty, high economic policy uncertainty, high asset intensity, or low customer concentration. Finally, we report evidence that CEOs with manufacturing and finance backgrounds are associated with less cost stickiness, thus confirming the critical role of business-finance integration in cost management. In sum, these findings highlight the importance of talents in building a powerful manufacturing country. [ABSTRACT FROM AUTHOR]

This paper focuses on the adaptive containment control problem for nonlinear strict-feedback multi-agent systems with dynamic leaders. An adaptive controller is constructed by backstepping control, first-order filters and compensating signals. The ''explosion of complexity" phenomenon is avoided by introducing first-order filters in traditional backstepping control, and filter errors are handled with compensating signals. All adaptive laws are accumulated to the last step by using tuning functions. The whole control design method is divided into two parts. One is to design adaptive tracking control for dynamic leaders. The other is to design adaptive containment control for followers. Through the proposed control method, the closed-loop system is stable, and all followers can converge to the convex hull built by the leaders. The simulation studies can confirm the effectiveness of the proposed control method. [ABSTRACT FROM AUTHOR]

The effects of environmental chemicals on health outcomes may be underestimated due to deficiency of knowledge regarding the actions of compounds on toxico-pathogenic mechanisms underlying biological systems outcomes. In this regard, the current study aimed to explore the potential target-pathway-disease relationship attributed to bisphenol A (BPA) responses in target tissues. Computational methods including reverse pharmacophore mapping approach, structural similarity based search and kinome wide interaction profiling were employed with molecular docking validation. Gene ontology (GO) enrichment analysis and protein-protein interaction (PPI) network based illustrations were utilized to prioritize target-pathway and disease relationships. Data illustrated that BPA possessed multi-target nature since this chemical potentially interacted with various protein targets where many of these were validated through docking. Potential BPA targets were significantly enriched to various cellular signaling pathways including steroid biosynthesis, peroxisome proliferator-activated receptor gamma (PPARℽ) and cancer. Further, hypertension was prioritized as disease target. In addition, BPA targeted 17 cell signaling kinases encompassed in the human kinome. In addition, inflammatory (5-LO) and apoptosis regulators (Bcl-X and Bcl-2) were also explored as novel targets. Evidence indicates that the multi-target nature and plausible mechanisms underlying BPA actions in a system wide manner aids toward understanding of adverse effects. This observation may lead us to more precise method to elucidate the toxico-pathogenic mechanisms of BPA with an environmental health perspective. [ABSTRACT FROM AUTHOR]

Objectives: During the COVID-19 pandemic, older adults experience various challenges, including information uncertainties, financial pressure, and visit restrictions, which may lead to anxiety about the future. As a protective factor, sense of coherence (SOC) may play a role to reduce some psychological discomfort. This study aimed to analyze the relationships of SOC with anxiety, digital health literacy (DHL), information, and financial satisfaction among older adults during the outbreak. Methods: This is part of a large-scale DHL study with a cross-sectional survey across 41 countries. This study extracted data from three Asian countries (China, the Philippines, and Singapore) and included people aged ≥60. Structural equation modeling with path analysis was utilized to examine the relationships of SOC with anxiety about the future and other variables. Results: A total of 266 older adults were included, with 43.2% expressed anxiety about the future. DHL (β=–0.13, p < 0.05) and SOC (β=–0.26, p = 0.01) were negatively associated with anxiety, while financial and information satisfaction were not. However, financial satisfaction (β = 0.34, p < 0.01) and DHL (β = 0.32, p = 0.01) were positively associated with SOC. Higher SOC further mediated the negative relationships of DHL (β= −0.11, p = 0.004) and financial satisfaction (β= −0.12, p = 0.004) on anxiety of older adults. Conclusions: SOC had direct negative effect on anxiety and mediated the relationships between anxiety and DHL/financial satisfaction. Strategies should be developed to enhance SOC and DHL among older adults, as these capacities may help to manage anxiety during the pandemic. [ABSTRACT FROM AUTHOR]

The study explores the primary determinants of Indian OFDI in 26 developed and 81 developing countries by integrating a nuanced perspective of institutional distance with conventional location factors (2008–2018). Our findings indicate that asset augmentation and market-seeking motives are the primary OFDI drivers in developed and developing regions, respectively. Overall, the institutional environment demonstrates a positive association between Indian OFDI and the robust governance quality of the host country (excluding RS investments in developing region). However, only robust regulatory quality (RQ) & control of corruption (CC) are the primary IQ determinants significantly attracting OFDI in developed nations. Surprisingly, none of the WGI significantly drives OFDI in developing countries. However, the interaction effect reveals that only market-seeking investors from India are drawn to highly regulated (RQ), rule-based (RL) developing nations. The estimated FDI factors differ significantly depending on the destination, but RQ largely remains the crucial determinant across regions. [ABSTRACT FROM AUTHOR]

This paper investigates an effective controller design method for discrete-time linear system with parameter uncertainty, time-varying delay, input nonlinearity and process disturbance. A novel discrete-time quasi-sliding mode control (DQSMC) scheme is mainly proposed. Since the sliding mode bound is directly involved in the DQSMC law, the chattering bound can be accurately specified. By the proposed method, the dynamic of the sliding mode is unable to escape from the pre-given neighbourhood once it is attracted into the neighbourhood, in addition, the closed-loop system achieves the almost surely stable in mean square sense. Moreover, the proposed DQSMC provides a convenient method to simultaneously regulate the convergence rates of the sliding mode and the closed-loop system. Numerical example is provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)