bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics and thermodynamics of the water sorption of 2‐hydroxyethyl methacrylate/styrene copolymer hydrogels
Authors: Wang Jianquan , Wu Wenhui , Lin Zhihui 
Published: May 2008

AbstractA series of polymer hydrogels based on 2‐hydroxylethyl methacrylate and styrene were synthesized by bulk polymerization. The kinetic and thermodynamic swelling properties of these hydrogels were studied. The swelling mechanism of the hydrogels followed Fickian behavior. The diffusion coefficients, initial swelling rate, and maximum water uptake all decreased with the styrene content increasing because of the hydrophobicity of styrene. The swelling process was exothermic from 278 to 315 K, and the greater the styrene content was, the lower the enthalpy of mixing was in magnitude. The polymer–water interaction parameter, reflecting thermodynamic interactions, increased with increasing styrene content in the polymers. The negative values and trend of the actual partial molar enthalpy and entropy of dilution could be explained by the structuring of water through enhanced hydrogen bonding and hydrophobic interactions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of poly(N,N‐diethylacrylamide‐co‐acrylic acid) hydrogels with fast response rate in NaCl medium
Authors: Liu Hongliang , Bian Fengling , Liu Mingzhu , Chen Shilan 
Published: May 2008

AbstractA series of thermo‐ and pH‐sensitive poly (N,N‐diethylacrylamide‐co‐acrylic acid) (P(DEA‐co‐AA)) hydrogels were prepared in NaCl aqueous solutions with different concentrations. Swelling and deswelling studies showed that in comparison with conventional P(DEA‐co‐AA) hydrogels (prepared in distilled water), the P(DEA‐co‐AA) hydrogels thus prepared had almost the same volume phase transition temperature (VPTT), but exhibited much faster response rates as the temperature was raised above their VPTT. Besides, the hydrogels prepared by this method had faster response rates in low pH buffer solutions, and the response rates increased with the increased concentration of the NaCl solutions used during the polymerization. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
N‐(2‐hydroxypropyl)methacrylamide‐based polymer conjugates with pH‐controlled activation of doxorubicin. I. New synthesis, physicochemical characterization and preliminary biological evaluation
Authors: Etrych Tomáš , Mrkvan Tomáš , Chytil Petr , Koňák Čestmír , Říhová Blanka , Ulbrich Karel 
Published: May 2008

AbstractNew method of synthesis of water‐soluble polymer‐drug conjugates, exhibiting remarkable anticancer activity in mice models, has been developed. In the conjugates, an anticancer drug doxorubicin (DOX) is attached to a polymer carrier based on N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymer via a hydrolytically labile hydrazone bond. New methacrylamide‐type comonomers, containing either hydrazide group or hydrazon of DOX, were used for copolymerization with HPMA. In contrast to the synthetic procedure described earlier the new method is simpler, cheaper, and results in a better‐defined conjugate structure. The conjugates are fairly stable in buffer at pH 7.4 (model of blood stream) but release DOX under mild acid conditions modeling the tumor microenvironment. The conjugates showed significant in vivo antitumor activity in treatment of T‐cell lymphoma EL‐4 bearing mice with up to 100% long‐term survivors. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
A comparison of current and historical fish assemblages in a Caribbean island estuary: conservation value of historical data
Authors: Smith K. L. , Corujo Flores I. , Pringle C. M. 
Published: May 2008

Abstract
Historical data are often one of the only resources available for documenting and assessing causes of environmental change, particularly in developing regions where funding for ecological studies is limited. In this paper, previously unpublished data from a year‐long study (1977) of the fish community of the Espiritu Santo estuary are presented. This dataset is among the oldest and most extensive surveys of a Caribbean island estuarine fish community.
A comparison of these historical data with data collected in June and July 2004 using identical sampling methods allowed description of potential long‐term changes in the fish community, identification of vulnerable species, and assessment of potential drivers of change.
Results strongly suggest a decline in species richness and abundance in the Espiritu Santo estuarine fish community, with greater declines in freshwater‐tolerant than marine or euryhaline species. Declines in freshwater inflow to the estuary, due to large‐scale upstream water abstractions for municipal use, have increased since the initial 1977 survey.
This is the first study to examine long‐term change in the fish community of a tropical island estuary. Additional research and conservation efforts are needed to understand mechanisms of change and to protect Caribbean island estuarine fish communities.
Copyright © 2008 John Wiley & Sons, Ltd.
Conserving indigenous crayfish: stock assessment and habitat requirements in the threatened Austropotamobius italicus
Authors: Brusconi Sara , Bertocchi Silvia , Renai Barbara , Scalici Massimiliano , Souty‐Grosset Catherine , Gherardi Francesca 
Published: May 2008

Abstract
As part of the Austropotamobius pallipes species complex, the crayfish Austropotamobius italicus is a species of community interest whose preservation requires the designation of Special Areas of Conservation (SACs) (Annex II, EU Habitats Directive). This study aimed at (1) assessing the conservation status of this threatened indigenous species by stock assessment in central Italy and (2) identifying some aspects of its elective habitat.
Surveys were conducted in nine streams harbouring A. italicus (streams WI) and in 10 streams where crayfish populations became extinct at least 5 years before the study (streams WO).
The results confirmed that A. italicus is a K‐selected species, with a relatively slow growth rate (males: 0.34; females: 0.37) and a long life expectancy (males: 8.2 years; females: 7.8 years). The extant populations are healthy, showing balanced sex‐ratios and well structured age‐class compositions. Mortality is mainly due to fishing, which is illegal in Tuscany.
Principal Components Analyses showed that the streams WI and WO differ in the abundance of allochthonous plant detritus but not in the taxonomic composition of their macroinvertebrate communities. Age classes were found to be spatially segregated, juveniles mainly using cobbles as substrates and adults seemingly avoiding them.
The loss of the pristine riverine landscape seems to have been responsible, together with illegal fishing, for the local extinction of the species. As a consequence, retaining, enhancing, and restoring the habitat and its complexity are required for the preservation of A. italicus.
The designation of SACs might help in this endeavour if accompanied by programmes aimed at publicizing the need for conservation of this species. Unfortunately, crayfish‐focused projects supported by LIFE in Italy since 1992 (4%) and the SACs involved (1.4%) have been relatively few, despite the poor conservation status of this species and its well recognized ecological role.
Copyright © 2008 John Wiley & Sons, Ltd.
Works and representation
Authors: Day Ronald E. 
Published: May 2008

AbstractThe concept of the “work” in art differs from and challenges traditional concepts of the “work” in bibliography. Whereas the traditional bibliographic concept of the work takes an ideational approach that incorporates mentalist epistemologies, container‐content metaphors, and the conduit metaphor of information transfer and re‐presentation, the concept of the work of art as is presented here begins with the site‐specific and time‐valued nature of the object as a product of human labor and as an event that is emergent through cultural forms and from social situations. The account of the work, here, is thus materialist and expressionist rather than ideational. This article takes the discussion of the work in the philosopher Martin Heidegger's philosophical‐historical account and joins this with the concept of the work in the modern avant‐garde, toward bringing into critique the traditional bibliographic conception of the work and toward illuminating a materialist perspective that may be useful in understanding cultural work‐objects, as well as texts proper.
Asymmetric Ligand‐Exchange Reaction of Biphenol Derivatives and Chiral Bis(oxazolinyl)phenyl–Rhodium Complex
Authors: Inoue Hiroko , Ito Jun‐ichi , Kikuchi Makoto , Nishiyama Hisao 
Published: May 2008

AbstractChiral bis(oxazolinyl)phenyl–rhodium acetate complex can enantioselectively capture 1,1′‐binaphthol derivatives by ligand‐exchange reaction. The structure of the bis(oxazolinyl)phenyl–rhodium biphenol and binaphthol complexes were confirmed by X‐ray analysis.
Asymmetric Friedel–Crafts Alkylation of Electron‐Rich N‐Heterocycles with Nitroalkenes Catalyzed by Diphenylamine‐Tethered Bis(oxazoline) and Bis(thiazoline) ZnII Complexes
Authors: Liu Han , Lu Shao‐Feng , Xu Jiaxi , Du Da‐Ming 
Published: May 2008

AbstractThe asymmetric Friedel–Crafts alkylation of electron‐rich N‐containing heterocycles with nitroalkenes under catalysis of diphenylamine‐tethered bis(oxazoline) and bis(thiazoline)‐ZnII complexes was investigated. In the reaction of indole derivatives, the complex of ligand 4 f with trans‐diphenyl substitutions afforded better results than previously published ligand 4 e with cis‐diphenyl substitutions. Excellent yields (up to greater than 99 %) and enantioselectivities (up to 97 %) were achieved in most cases. The complex of ligand 4 d bearing tert‐butyl groups gave the best results in the reactions of pyrrole. Moderate to good yields (up to 91 %) and enantioselectivities (up to 91 %) were achieved in most cases. The origin of the enantioselectivity was attributed to the NH–π interaction between the catalyst and the incoming aromatic system in the transition state. Such an interaction was confirmed through comparison of the enantioselectivity and the absolute configuration of the products in the reactions catalyzed by designed ligands.
Rhodium‐Catalyzed Silylation of Aromatic Carbon–Hydrogen Bonds in 2‐Arylpyridines with Disilane
Authors: Tobisu Mamoru , Ano Yusuke , Chatani Naoto 
Published: May 2008

AbstractThe rhodium(I)‐catalyzed regioselective silylation of the ortho carbon–hydrogen bond in 2‐arylpyridines with disilane is described. For example, the reaction of 2‐(2‐methylphenyl)pyridine with 2 equivalents of hexamethyldisilane in the presence of 5 mol % [RhCl(cod)]2 (cod=1,5‐cyclooctadiene) in o‐xylene at 130 °C for 15 h gave 2‐[2‐methyl‐6‐(trimethylsilyl)phenyl]pyridine in 86 % yield. In contrast to silylation with hydrosilanes, hydrogen acceptors are not required to achieve high conversion. A variety of substituents, including alkoxy, amine, ester, and fluorinated groups, are compatible with this catalysis. When substrates containing two ortho CH bonds are used, monosilylated products are obtained selectively by utilizing the 3‐methyl‐2‐pyridyl group as a directing group.
Synthesis of Enantiomerically Pure 1,2,3,4‐Tetrahydro‐β‐carbolines and N‐Acyl‐1‐aryl Ethylamines by Rhodium‐Catalyzed Hydrogenation
Authors: Enthaler Stephan , Erre Giulia , Junge Kathrin , Addis Daniele , Kadyrov Renat , Beller Matthias 
Published: May 2008

AbstractThe rhodium‐catalyzed asymmetric hydrogenation of different enamides, in particular, dihydro‐β‐carboline derivates, was investigated in the presence of chiral phosphorus ligands. Enantioselectivities of up to 99 % ee were obtained after ligand screening and optimization of the reaction conditions. The scope and limitation of the catalysts were shown in the synthesis of optically active tetrahydro‐β‐carbolines and other benchmark N‐acyl‐1‐aryl ethylamines.
Optimal linear LQG control over lossy networks without packet acknowledgment
Authors: Sinopoli Bruno , Schenato Luca , Franceschetti Massimo , Poolla Kameshwar , Sastry Shankar 
Published: May 2008

AbstractThis paper is concerned with control applications over lossy data networks. Sensor data is transmitted to an estimation‐control unit over a network, and control commands are issued to subsystems over the same network. Sensor and control packets may be randomly lost according to a Bernoulli process. In this context, the discrete‐time linear quadratic Gaussian (LQG) optimal control problem is considered.It is known that in the scenario described above, and for protocols for which there is no acknowledgment of successful delivery of control packets (e.g.UDP‐like protocols), the LQG optimal controller is in general nonlinear. However, the simplicity of a linear sub‐optimal solution is attractive for a variety of applications. Accordingly, this paper characterizes the optimal linear static controller and compares its performance to the case when there is acknowledgment of delivery of packets (e.g.TCP‐like protocols). Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
An asymmetry subsethood‐based neural fuzzy network
Authors: Lin Cheng‐Jian , Lin Tzu‐Chao , Lee Chi‐Yung 
Published: May 2008

AbstractThis paper proposes a novel asymmetric subsethood‐based neural fuzzy network (ASNFN) that identifies and controls nonlinear dynamic systems. ASNFN has the flexibility to handle both numeric and linguistic inputs. The numeric inputs in ASNFN are fuzzified by input nodes as tunable feature fuzzifiers. Connections in ASNFN are represented by pseudo‐Gaussian fuzzy sets which provide the neural fuzzy network with higher flexibility and attain more accurate optimization. An online self‐constructing learning algorithm that is constructed and implemented in ASNFN consists of structural learning and parametric learning, and would create adaptive fuzzy logic rules. Computer simulations illustrate the performance and capability of the proposed model in identifying a dynamic system, in Iris data classification, and in approximating a nonlinear function. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Mathematical model set‐point stabilizing controller design of a twin rotor MIMO system
Authors: Shih Ching‐Long , Chen Mao‐Lin , Wang Jiun‐Yaw 
Published: May 2008

AbstractIn this paper, set‐point stabilizing control of a two‐rotor MIMO helicopter system is studied. The mathematical model of the twin rotor MIMO system (TRMS) is derived from Lagrange dynamics, its dynamic characteristics such as equilibrium position, propeller thrust gravity compensation are analyzed. Based on the dynamics model, a nonlinear PD controller a fuzzy PID controller are designed for real‐time microcontroller set‐point stabilization control. The fuzzy PID controller has a slower response time than the nonlinear PD controller, but it is better than the latter concerning overshoots steady‐state errors. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Performance oriented control over networks: Switching controllers and switched time delay
Authors: Hirche Sandra , Chen Chih‐Chung , Buss Martin 
Published: May 2008

AbstractThe stability and performance of a networked control system (NCS) strongly depends on the communication quality, e.g., the communication time delay. Aiming for performance oriented control over networks in the presence of piecewise constant time delay, two novel control approaches are investigated. In the first approach, the time delay is monitored and an appropriate controller is selected. The second approach is based on the Quality‐of‐Service communication concept, where the time delay is adjustable and related to the network cost. Aiming for an optimal trade‐off between network cost and control performance the controller, together with the time delay, is switched. Both approaches result in a switched system with switched (piecewise constant) delays. Sufficient stability conditions for the resulting switched time delay system are presented using a piecewise continuous Lyapunov‐Razumikhin function. A common Lyapunov function is derived for symmetric systems. The performance benefits for both approaches are demonstrated in numerical examples. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Adaptive control approach to uncertain longitudinal tire slip in traction control of vehicles
Authors: Nakakuki Takashi , Shen Tielong , Tamura Katsutoshi 
Published: May 2008

AbstractThis paper addresses the longitudinal traction control problem of vehicles. A nonlinear control law at the torque level is shown to cope with the unknown tyre reaction force. From a physical consideration of a vehicle, a decoupling controller design is considered, which enables us to make the controller design straightforward. A parameter estimator is introduced to adaptive control of the system with uncertain frictional coefficient. The proposed controller indicates the better control performance than that of a non‐adaptive or a conventional PI controller as evaluated in numerical simulation. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.
Transanal endoscopic microsurgery is a safe and reliable technique even for complex rectal lesions
Authors: Darwood R J , Wheeler J M D , Borley N R 
Published: May 2008

Abstract

Background
Transanal endoscopic microsurgery (TEM) is a minimally invasive technique for the excision of rectal lesions, with lower morbidity and mortality rates than open surgery. Following advances in laparoscopic colorectal surgery and endoscopic mucosal resection, this study evaluated the safety and efficacy of TEM in the treatment of complex rectal lesions.

Methods
All patients were entered into a prospective database. Complex lesions were identified as high (more than 15 cm from anorectal margin), large (maximum dimension over 8 cm), involving two or more rectal quadrants, or recurrent.

Results
Seventy-one lesions (13 carcinomas and 58 tubulovillous adenomas) were identified. The median duration of operation was 60 (interquartile range (i.q.r.) 30–80) min, with an estimated median blood loss of 0 (i.q.r. 0–10) ml. Median hospital stay was 2 (i.q.r. 1–3) days. One patient developed postoperative urinary retention and one returned with rectal bleeding that did not require further surgery. Two patients developed rectal strictures after operation that were dilated successfully. There was no recurrence of benign lesions during a median follow-up of 21 (i.q.r. 6·5–35) months.

Conclusion
TEM is a safe technique with low associated morbidity, even when used to excise complex rectal lesions. As such it remains the treatment of choice for rectal lesions not requiring primary radical resection.
Confinement in Nanopores at the Oxide/Water Interface: Modification of Alumina Adsorption Properties
Authors: Baca Manuel , Carrier Xavier , Blanchard Juliette 
Published: May 2008

AbstractThere is limited knowledge on the influence of the pore size on surface phenomena (adsorption, dissolution, precipitation, etc.) at the oxide/water interface and a better understanding of the space confinement in nanoscale pores should have practical implications in different areas, such as transport of contaminants in the environment or heterogeneous catalyst preparation, to name a few. To investigate the modifications of the oxide adsorption properties at the oxide/water interface in a confined environment, the surface acidobasic and ion adsorption properties of six different aluminas (5 porous commercial aluminas with pore diameters ranging from 25 to 200 Å and 1 non‐porous alumina) were determined by means of acid–base titration and Ni(II) adsorption. It is shown that the confinement has a moderate impact on the alumina adsorption capacity because all materials have similar surface charging behaviours and ion saturation coverages. However, a confined geometry has a much larger impact on the ion adsorption constants, which decrease drastically when the average pore diameter decreases below 200 Å. These results are discussed in terms of nanoscale pore space confinement.
Generation and Reactivity of Enantiomeric (BINOLato)Ni+ Complexes with Chiral Secondary Alcohols in the Gas Phase
Authors: Novara Francesca R. , Gruene Philipp , Schröder Detlef , Schwarz Helmut 
Published: May 2008

AbstractIn the presence of secondary alcohols, electrospray ionization of dilute methanolic solutions of nickel(II) salts and 1,1′‐bis‐2‐naphthol (BINOL) leads to complexes of the formal composition [(BINOLato)Ni(CH3CH(OH)R)]+ (BINOLato refers to a singly deprotonated (R)‐ or (S)‐1,1′‐bis‐2‐naphthol ligand; R=CH3, C2H5, n‐C3H7, n‐C4H9, n‐C5H11, n‐C6H13, c‐C6H11, and C6H5). Upon collision‐induced dissociation, each mass‐selected nickel complex either loses the entire secondary alcohol ligand or undergoes bond activation followed by elimination of the corresponding ketone, as revealed by deuterium labeling. When enantiomeric BINOLato ligands (R or S) are combined with chiral secondary alcohols (R or S), differences in the branching ratios between these channels for the two stereoisomers of the secondary alcohols provide insight into the chiral discrimination operative in the CH‐ and OH‐bond activation processes. For saturated alkan‐2‐ols, the chiral discrimination is low, and if any preference is observed at all, ketone elimination from the homochiral complexes (R,R and S,S) is slightly favored. In contrast, the diastereomeric (BINOLato)Ni+ complexes of 1‐phenylethanol exhibit preferential ketone losses for the heterochiral systems (S,R and R,S).
Spectroelectrochemical and Computational Studies on the Mechanism of Hypoxia Selectivity of Copper Radiopharmaceuticals
Authors: Holland Jason P. , Barnard Peter J. , Collison David , Dilworth Jonathan R. , Edge Ruth , Green Jennifer C. , McInnes Eric J. L. 
Published: May 2008

AbstractDetailed chemical, spectroelectrochemical and computational studies have been used to investigate the mechanism of hypoxia selectivity of a range of copper radiopharmaceuticals. A revised mechanism involving a delicate balance between cellular uptake, intracellular reduction, reoxidation, protonation and ligand dissociation is proposed. This mechanism accounts for observed differences in the reported cellular uptake and washout of related copper bis(thiosemicarbazonato) complexes. Three copper and zinc complexes have been characterised by X‐ray crystallography and the redox chemistry of a series of copper complexes has been investigated by using electronic absorption and EPR spectroelectrochemistry. Time‐dependent density functional theory (TD‐DFT) calculations have also been used to probe the electronic structures of intermediate species and assign the electronic absorption spectra. DFT calculations also show that one‐electron oxidation is ligand‐based, leading to the formation of cationic triplet species. In the absence of protons, metal‐centred one‐electron reduction gives the reduced anionic copper(I) species, [CuIATSM]−, and for the first time it is shown that molecular oxygen can reoxidise this anion to give the neutral, lipophilic parent complexes, which can wash out of cells. The electrochemistry is pH dependent and in the presence of stronger acids both chemical and electrochemical reduction leads to quantitative and rapid dissociation of copper(I) ions from the mono‐ or diprotonated complexes, [CuIATSMH] and [CuIATSMH2]+. In addition, a range of protonated intermediate species have been identified at lower acid concentrations. The one‐electron reduction potential, rate of reoxidation of the copper(I) anionic species and ease of protonation are dependent on the structure of the ligand, which also governs their observed behaviour in vivo.