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随着中国能源转型发展，以电网为核心的电-气互联综合能源系统（integrated electricity and gas systems,IEGS）有望成为能源传输的新载体。IEGS作为能源互联网的基础和过渡，对于提升能源利用效率具有重要意义。随着电转气技术的快速发展，电网和天然气网间具备了双向耦合关系。两网耦合程度不断加深，分别对两网进行研究的传统分析方法可能难以满足IEGS运行的可靠性和经济性，因此越来越多的学者将两网视为一个整体展开协同优化等方面的研究。首先介绍了电转气技术的研究及应用现状，在此基础上，介绍了考虑电网和气网双向耦合的IEGS统一潮流模型建模和求解方法，总结了国内外相关研究现状，并分析了统一潮流模型建模中还可进一步完善提高的关键点。进一步，归纳了面向IEGS的规划、运行调度、最优潮流计算等方面的研究现状。最后，分析了IEGS运行安全性方面的主要研究方向及问题，以期为后续研究提供参考。

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office 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.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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.)

Copyright of Journal of Geodesy & Geodynamics (1671-5942) is the property of Editorial Board Journal of Geodesy & Geodynamics 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.)

Copyright of Advances in Earth Science (1001-8166) is the property of Advances in Earth Science Editorial Office 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.)

Copyright of Feed Industry is the property of Liaoning Provincial Institute of Agricultural Mechanization 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.)

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Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui 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.)

[Objective]To establish the characteristic fingerprint of tobacco traceability by the determination of mineral elements in tobacco leaves combined with chemometrics method, and to verify the accuracy and reliability of the method. [Method]The contents of inorganic elements in 25 tobacco leaf samples planted in soils from five different areas were analyzed by ICP-OES combined with microwave digestion method. The data matrix was sequentially analyzed by one-way-ANOVA, principal component analysis and discriminant analysis. [Result]There were significant differences among tobacco leaves planted in different soils about the contents of mineral elements. The first two principal components obtained by principal component analysis could approximately reflect the information of original data, and realized the traceability of tobacco planted in soils from different regions by analyzing the mineral elements’ contents. Fisher discriminant analysis and leave-one-out cross-validation test were performed to validate these results, ideal verification results were obtained, and the correct discrimination rate were 100%, respectively. [Conclusion]Based on the specific differences of inorganic elements could discriminate the geographical origins of tobacco. [ABSTRACT FROM AUTHOR]

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office 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.)

Two coordination polymers ([Co(tib) (mpda) (H2 O)2 ] ·H2 O, [Ni(tib) (mpda) (H2 O)2 ] ·H2 O) were synthesized based on flexible phenyldiacetic acid, and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and X-ray single crystal diffraction. In the structure of [Ni(tib)(mpda)(H2 O)2 ]·H2 O, the tib ligands coordinate as three nodes with Co(II) ions to form a 2D grid plane; cis-mpda ligands are attached to the 2D grid face as end-bases; through the O--H...O interaction between the mpda virgin carboxyl O and the coordinated water molecule (bond length of O1...O3 is 0. 262 4 nm, ∠O5--H5A...O2 = 155. 41°), a three-dimensional supramolecular network structure is formed. Two coordination polymers belong to the heterogeneous crystal structure. The specific surface areas of the two coordination polymers are 54 and 58 m² / g, respectively. [Ni(tib) (mpda) (H2 O)2 ] ·H2 O has a complete cyclic voltammetric curve (reduction and oxidation potentials are 0. 205 and 0. 563 V, respectively) and good scanning rate. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press 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.)

Copyright of Journal of Clinical Pediatric Surgery is the property of Journal of Clinical Pediatric Surgery Editorial Office 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.)

Objective: To investigate the effects of long-chain non-coding RNA (LncRNA) MYU on the cycle distribution, cell proliferation, migration, invasion, and apoptosis of glioma cells, and to preliminarily explore its mechanism of action. Methods: The expression of LncRNA MYU in human brain normal glial cells HEB and glioma cells (U-251MG, A172, SHG139) was detected by real- time fluorescent quantitative PCR (RT-qPCR). SHG139 cells were selected and divided into normal control (NC) group, si-con group, and si-LncRNA MYU group for transfection experiments, and RT-qPCR was applied to detect the transfection effect. The effects of silencing LncRNA MYU on the cell cycle distribution and apoptosis, cell proliferation and, cell migration and invasion of SHG139 cells were detected respectively by flow cytometry, cell counting kit (CCK-8), and Transwell experiments. Western blot was used to detect the expression of matrix metalloproteinase (MMP-2), MMP-9, Cleaved caspase-3, Cleaved caspase-9, and Phosphatidylinositol-3-hydroxykinase/protein kinase B (PI3K/Akt) signaling pathway-related proteins. Results: The expression of LncRNA MYU in glioma cell lines was significantly higher than that in normal human brain glial cells(P<0.05), thereby SHG139 cells with the highest expression levels were selected for transfection experiments. Silencing LncRNA MYU can significantly induce G0-G1 phase arrest, inhibit the proliferation, migration and invasion, and induce apoptosis in SHG139 cells(P<0.05). Silencing LncRNA MYU can significantly inhibit the expression of MMP-2, MMP-9, p-PI3K and p-AKT, and promote the expression of Cleaved caspase-3 and Cleaved caspase-9(P<0.05). Conclusion: Silencing LncRNA MYU can induce G0-G1 phase arrest, inhibit cell proliferation, migration and invasion, and promote cell apoptosis in glioma cells, and its mechanism may be related to the inhibition of PI3K/AKT signaling pathway. [ABSTRACT FROM AUTHOR]

This study aimed to explore the effects of different mulching films on machine-picked cotton yield, economic benefit, and mulching film recovery in southern Xinjiang. The experiment was conducted in 2021 in the cotton field of Shaya County, Aksu Prefecture, Xinjiang Uygur Autonomous Region. The bare land was used as the control to set two different mulching films, namely, high castle mulching film（GB）and common PE mulching film（PE）. The yield and economic benefits of cotton under different mulching films were statistically analyzed, and the residual mulching films were recovered. The results showed that, compared with the common PE film and bare land, GB could significantly increase the soil temperature of the 0–10 cm soil layer in the cotton field during the seedling stage（20 d after sowing）by 0.78 ℃ and 2.19 ℃, respectively. The water retention rate at 30th day was 2.51 percentage points higher than that of common PE film, which was effective for increasing temperature and preserving soil moisture. The yield and economic benefit of cotton were significantly increased in GB. Compared with the common PE mulching film and bare land, the seed cotton yield increased by 9.91% and 33.13%, and the profit in GB and PE mulching increased by 55.77% and 27.22%, respectively, compared that in bare land which was beneficial to cotton growth and yield. In addition, the tensile load and fracture nominal strain GB of before and after use were higher than that of ordinary PE film, and the disposable mechanical recovery rate exceeded 80%. This study showed that high castle mulching film had a better effect on increasing temperature and preserving soil moisture in machine-picked cotton fields in southern Xinjiang, was more beneficial to cotton growth and yield than common PE film and bare soil, and the recovery efficiency was higher. To promote the green and sustainable development of cotton fields in southern Xinjiang, it could be preferential for widespread use. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jiangsu University (Natural Science Edition) / Jiangsu Daxue Xuebao (Ziran Kexue Ban) is the property of Editorial Department of Journal of Jiangsu University (Natural Science Edition) 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.)

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research 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.)

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office 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.)

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office 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.)

Copyright of Food Science & Technology & Economy is the property of Grain Science & Technology & Economy Editorial Office 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.)

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Raw materials are usually stored in the form of particles in silos, such as the food, chemical, and pharmaceutical field. The motion of granular materials can vary greatly in the flow of gases and liquids, due to their discrete particle aggregates. It is difficult to accurately explain using traditional theories, such as solid or fluid mechanics, and condensed matter physics. Particularly, the silo can serve as one of the most important carriers to store the particulate matter. It is still lacking in a comprehensive unified theory for the silo subjected to complex forces. Among them, the irregularity of rice seeds has a significant impact on the unloading in the silo, due to the nature of loose particles. Therefore, it is of great significance to clarify the impact of rice seed discharge flow in the silo. Auxiliary devices can also be added to transform the central into the overall flow bin. Simple and effective fluid modification can be used to adjust the structure of silos for the better particle flow. This study aims to explore the impact mechanism of different fluid modifications on the flow of rice seed particles during discharge in the silo. The transformation of the population flow pattern was achieved from the central to the overall flow for better population flow. The discrete element method (DEM) was selected to construct the traditional silo, vertical disturbance, and horizontal disturbance silo models. Rice seed particle models were established for the discharge simulation. The flow pattern was compared with the actual discharge experiment in the silo. A series of experiments was also conducted to verify the accuracy of the discrete element model and numerical simulation. The mass flow index (MFI) and z-axis particle velocity indicated that the particle velocity in the central region of traditional and vertically disturbed silos decreased with the increase of particle stacking height, whereas, the particle velocity increased in the sidewall region. There was a decrease in the particle velocity in the sidewall area of the horizontally disturbed silo, as the particle stacking height increased, whereas, the particle velocity increased in the central area. Traditionally, the conversion heights of the flow pattern were 130, 118, and 130 mm, respectively, in the vertically and horizontally disturbed silos. There was a variation in the vertical, horizontal, and angular velocity in the different areas of the silo. Specifically, the vertical velocity of the population decreased by 34.82% and 83.46%, respectively, compared with the traditional flow area of the silo under the action of the vertical and horizontal fluid. The fluctuation of population horizontal velocity increased, as the height of particle accumulation decreased in the silo population. The standard deviations of particle horizontal velocity were 0.027 3, 0.018 7, and 0.010 3, respectively, in the traditional silos, vertical and horizontal disturbance silos. There were similar changes in the particle angular velocity in the center and sidewall areas of traditional and vertical disturbance silos. The peak angular velocity was smaller in the center area of vertical disturbance silos, compared with the traditional silos. The variation of particle angular velocity was similar to the traditional silo in the flow area of a horizontal disturbance. But there was a small variation of particle angular velocity in a horizontal disturbance silo. The finding can provide the theoretical reference for the fluid design standards, structural and positional parameters, particularly for the high available area of the silo. [ABSTRACT FROM AUTHOR]

Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department 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.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology 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.)

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Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office 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.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office 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.)

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Copyright of Mechanical & Electronic Control Engineering is the property of Omniscient Pte. 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.)

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Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department 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.)

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Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department 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.)

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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.)

Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department 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.)

Cassava cultivation is low-cost and high-yielding, and tubers, stems and leaves can be widely utilized in the food medicine and light industry. However, cassava planting is mainly manual work at present. There is an urgent need to develop precision planting machines suitable for the agronomic requirements of cassava planting. A seeder is the core component of a precision planting machine, including the real-time and pre-cut seed-cutting type. Among them, the real-time seed cutting cannot realize the automatic sowing, due to the long and complicated shape of the cassava seed rods, while the low persistence of manual seed feeding and serious leakage. A seed cutter can be used to cut the cassava seed stems into seed stems of about 150 mm in length in pre-cut seeding. An automatic continuous and controlled seeding of cassava seed stems can be achieved through the seed discharge mechanism after cleaning. The lifting type seed rower has been improved to add the gravity seed cleaning mechanism, while the structure of the clamping plate has been optimized for the seed rowing effect. But the leakage filling still exists so far. Some research has been conducted on the seeders, such as slotted wheels, and single roller types. However, it is very necessary to improve the seed filling performance and qualification index, when seeding cassava seed stems with the existing pre-cut seed sower, because the cassava seed stems are cylindrical woody stalks of a certain length with surfaces of complex physical characteristics. Particularly, the performance of cassava precision seeding needs to be improved, due to a complex process with the multi-factor change. This study aims to improve the seed filling effect and low qualification index of pre-cut seeding type cassava precision seeder. A precision cassava seeding mechanism was designed with pre-cut seeding and friction belt, consisting of seed drop slide, active roller, type hole friction belt, support roller group, driven roller, and seed storage box. The basic structure and working principle of the seed-rowing mechanism were described to determine the parameters of key components. The main factors were then determined with the seed-filling performance of the seeding mechanism, according to the shape, number, installation inclination, and speed of the typed hole on the friction belt, as well as the thickness of the seed stem layer. The discrete element method (DEM) was used to establish a simulation model of the "seed stem group-hole friction zone". The single-factor simulation was realized to clarify the influence of each factor on the seed-filling performance. The optimal combination of factors and parameters was determined after quadratic regression and orthogonal rotational simulation. Taking the installation inclination angle of the seeding hole friction zone, the thickness of the seeding stem layer, and the speed of the seeding hole friction zone as the factors, the mathematical regression model of each factor was established for the evaluation index. The results showed that the influencing factors of the seed filling index and the leakage index were ranked in descending order of the speed of the type hole friction belt, the installation angle of the type hole friction belt, and the thickness of the seed stem layer. The optimal combination of factors and parameters was achieved in the bench test. The seed filling qualification index was 94.13% for the precut cassava-type friction belt precision seeding mechanism, and the leakage index was 3.77% when the thickness of the seed stem layer was rounded to 220-280 mm, the speed of the friction belt was 0.6 m/s, the installation inclination of the friction belt was 45°, the shape of the friction belt was C-shaped and the number of holes was 12. A better performance was achieved, where the seed filling index and the leakage index were 94.13% and 3.77%, respectively. The finding can provide a theoretical reference for the development of cassava precision seeders. [ABSTRACT FROM AUTHOR]

Copyright of Science Technology & Engineering is the property of Chinese Society of Technology Economics 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.)

Copyright of Transactions of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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.)

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering 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.)

Copyright of Journal of Clinical Pediatric Surgery is the property of Journal of Clinical Pediatric Surgery Editorial Office 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.)

The molecular-mass and its distribution of poly（p-phenylene terephthamide）(PPTA） directly affect the spinning performance of aramid fiber. The hydrogen bonds between PPTA backbones make PPTA insoluble in common organic solvents such as chloroform， which cannot meet the test requirements of proton magnetic resonance， mass spectroscopy， and gel permeation chromatography （GPC). The soluble n-alkylated PPTAs are obtained by grafting a series of alkyl chains with different lengths and degrees of supersede on the N-position of PPTA backbones. The influence of alkyl lengths and alkylation conditions on relative molecular-mass and its distribution are further studied. Ethyl alkylated PPTA with the highest substitution degree of 98.6% enables to provide the lowest polydispersion coefficient and the more accurate molecular-mass distribution. The relationship between the average relative molecular-mass and the intrinsic viscosity in a specific viscosity range is obtained according to the Makhovink equation ［η］= 9. 96×10-3 Mw1.08 . These results could be utilized for optimizing PPTA synthesis and improving the performance of aramid fiber. [ABSTRACT FROM AUTHOR]

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications 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.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office 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.)