bluuebunny/crossref_metadata_2025 huggingface dataset:
Noncovalent Synthesis in Aqueous Solution and Spectroscopic Characterization of Multi‐Porphyrin Complexes
Authors: Gulino Fabio G. , Lauceri Rosaria , Frish Limor , Evan‐Salem Tamar , Cohen Yoram , De Zorzi Rita , Geremia Silvano , Di Costanzo Luigi , Randaccio Lucio , Sciotto Domenico , Purrello Roberto
Published: January 2006

The interactions of the tetracationic meso‐tetrakis(N‐methyl‐4‐pyridyl)porphyrin (H2TMPyP) and its metallo derivatives (MTMPyP) (where M=copper(II), zinc(II), and gold(III) with the octa‐anionic form (at neutral pH) of 5,11,17,23‐tetrasulfonato‐25,26,27,28‐tetrakis(hydroxycarbonylmethoxy)calix[4]arene (C4TsTc) lead to a series of complex species whose stoichiometry and porphyrin sequence can be easily tuned. Crystallographic, spectroscopic, and diffusion NMR studies converge towards a common picture in which a central 1:4 porphyrin/calixarene unit serves as a template for the formation of more complex species. These species arise by successive, stepwise addition of single porphyrin molecules above and below the plane of the 1:4 central core to ultimately give a 7:4 complex. Noticeably, the stoichiometry of the various complex species corresponds to the actual concentration ratio of porphyrins and calixarenes in solution allowing the stoichiometry of these species to be easily tuned. This behavior and the remarkable stability of these species allow homo‐porphyrin and hetero‐(metallo)porphyrin species to be formed with control of not only the stoichiometry but also the sequence of the porphyrin array. The flexibility and ease of this approach permit, in principle, the design and synthesis of porphyrin arrays for predetermined purposes. For example, we have shown that it is very easy to design and obtain mixed porphyrin species in which a foreseen photoinduced electron‐transfer is indeed observed.
Micelle‐to‐Vesicle Transition Induced by Organic Additives in Catanionic Surfactant Systems
Authors: Yin Haiqing , Lei Sheng , Zhu Shengbao , Huang Jianbin , Ye Jianpin
Published: January 2006

A micelle‐to‐vesicle transition (MVT) induced by the addition of a series of apolar hydrocarbons (n‐butylbenzene, n‐hexane, n‐octane, and n‐dodecane) to the catanionic surfactant system n‐dodecyltriethylammonium bromide/sodium n‐dodecylsulfate (DTEAB/SDS) has been investigated for the first time by means of rheology and turbidity measurements, dynamic light scattering (DLS), and transmission electron microscopy (TEM). Interestingly, a MVT can take place within certain micellar regions, which are dependent on the structure and chain length of the hydrocarbon. However, these hydrocarbons are unable to induce a MVT in another catanionic surfactant system, namely, n‐dodecyltriethylammonium bromide/sodium n‐dodecylsulfonate (DTEAB/SDSO3), in which the molecular interactions are weaker than in the DTEAB/SDS system. On the other hand, polar additives, such as n‐octanol and n‐octylamine, exhibit much higher efficiency and activity in inducing MVT than hydrocarbons in both DETAB/SDS and DTEAB/SDSO3. Moreover, DLS, TEM, and time‐resolved fluorescence quenching (TRFQ) results demonstrate that the ratio of vesicles to micelles in the system can be actively controlled by addition of polar additives. Possible mechanisms for the above phenomena are presented, and the potential application of controllable micelle/vesicle systems in the synthesis of tailored bimodal mesoporous materials is discussed.
Electrodeposition and Properties of an Amorphous Ni‐W‐B Alloy before and after Heat Treatment
Authors: Yang Fang‐Zu , Ma Zhao‐Hai , Huang Ling , Xu Shu‐Kai , Zhou Shao‐Min
Published: January 2006

To strengthen the properties of Ni‐W alloy, dimethylamine borane (DMAB) was added to an alloy Ni‐W electrolyte solution and a ternary Ni‐W‐B alloy was electrodeposited. The electrodeposition, crystallographic structure, surface morphology, heat treatment and corrosion resistance, of the alloy were studied by DSC, XRD, SEM and electrochemical techniques. The results showed that the structure of the alloy was greatly affected by the cooperation of boron compound. DSC experiment combined with X‐ray diffractometry indicated that the obtained Ni‐W‐B alloy was still in amorphous structure although W content in the alloy was decreased by the addition of DMAB. After heat treatment at 400 °C for 1 h, the microhardness was increased from 612 to 947 kg·mm−2 that was comparative to Cr coating. The appearance of the as‐plated coating was in fine and slice grains and kept almost no change after heat treatment. In w=0.03 NaCl solution the as‐plated coating presented very good corrosion resistance. After the coating was heat‐treated its corrosion resistance was enhanced.
Theoretical Studies on Electronic Spectra and Second‐order Nonlinear Optical Properties of Glucosyl Substituted Barbituric Acid Derivatives
Authors: Feng Jing‐Dong , Yan Li‐Kai , Su Zhong‐Min , Kan Yu‐He , Lan Ya‐Qian , Liao Yi , Zhu Yu‐Lan
Published: January 2006

AM1 semi‐empirical method was used to optimize the barbituric acid derivatives substituted with glucosyl B1–5(series B), and the thiobarbituric acid derivatives substituted with glucosyl T1–5 (seriesT). Based on the optimized structures, INDO/CI method was adopted to calculate the electronic spectra. Meanwhile, the second‐order nonlinear optical (NLO) coefficients βμ were calculated with the sum‐over‐state (SOS) formula. The results show that when the number of glucosyl units was increased, |βμ| values of the barbituric and thiobarbituric acid derivatives were both enhanced, especially for thiobarbituric acid derivatives. It indicates that non‐conjugated substituted group could also improve NLO properties of materials when the number of repeated units was increased. Additionally, the absorption bands appearing in UV area are consistent with the proper change of the number of glucosyl units, and consequently it can be concluded that the high transparencies of all systems were scarcely varied.
Image Contrast Inversion of a Solvent Cast SEBS Film
Authors: Han Xia , Xu Jian , Liu Hong‐Lai , Hu Ying
Published: January 2006

The image contrast inversion was investigated in detail when soft polymeric materials were imaged with tapping mode atomic force microscopy (TM‐AFM). Solvent cast film of polystyrene‐block‐poly(ethylene/butylene)‐block‐polystyrene (SEBS) triblock copolymers was used as a model system in this study, which showed phase separation domains with a size of several tens of nanometers. AFM contrast reversal process, through positive image, to an intermediary and till negative image, could be clearly seen in height images of the soft block copolymer using different tapping force. The higher tapping force would lead to not only contrast inversion, but also the different size of the microdomains and different roughness of the images. Moreover, contrast inversion was explained on the basis of attractive and repulsive contributions to the tip‐sample interaction and indentation of the soft domains.
Synthesis and Crystal Structure of a New Oxovanadium(V)Multicomponent Complex with Acylhydrazone and Benzoylhydrazine
Authors: Zhou Yin‐Zhuang , Chen Rui‐Jin , Tu Shu‐Jie , Lu Xiao‐Ming
Published: January 2006

A new oxovanadium(V) complexwith the mixed ligand of 2‐oxopropionic acid benzoylhydrazone (C10H10N2O3) and benzoylhydrazine (C7H8N2O), VO(C7H7N2O)(C10H9N2O3), has been synthesized. Its structure was determined by single crystal X‐ray diffraction analysis. The crystal belongs to monoclinic system with space group P21/n and cell parameters: a=1.1136(4) nm, b=0.6217(2) nm,c=2.6038(9) nm,β=97.182(6)(, V=1.7887(11) nm3, Z=4, F(000)=836, Mr407.28, Dc=1.512 g/cm3, μ(Mo Kα)=0.592 mm−1, R1=0.0445, wR2=0.1203. Vanadium atom is 6‐coordinated by carboxyl and carbonyl O atoms and N atom of one tridentate C10H10N2O3 to form two stable five‐membered rings with the same edge, and the other coordinated atoms of N and O come from one bidentate benzoylhydrazine C7H8N2O. The title complex has a six‐coordinated V center [VO(N2O3)] with a distorted octahedral arrangement. In the crystal lattice, there are hydrogen bonding interactions between two molecules.
Synthesis of N‐Alkylhexahydroazepine by One‐step Catalytic Alkylation and Hydrogenation of Caprolactam
Authors: Du Jun‐Ming , Shen Wei , Xu Hua‐Long
Published: January 2006

A new synthetic method for the preparation of N‐alkylhexahydroazepine by one‐step catalytic alkylation and hydrogenation of caprolactam has been developed. Alkylated caprolactam was firstly synthesized by catalytic alkylation of caprolactam with alcohol and then directly hydrogenated into N‐alkylhexahydroazepine over Cu‐ZnO/γ‐Al2O3 catalyst.
Facile Microwave Assisted Liquid Phase Deposition Process to TiO2 Nanocrystallines
Authors: Zhang Liu‐Xue , Liu Peng , Su Zhi‐Xing
Published: January 2006

Anatase nanoparticles were successfully prepared via a facile microwave assisted liquid phase deposition (MW‐LPD) process with hexafluorotitanate ammonium (NH4)2TiF6 as precursor. Compared with the conventional LPD processes, the MW‐LPD technique could provide high yield quickly and crystallinity in a diluted precursor solution at a low temperature. The products were characterized by XRD and TEM. Their photocatalytic activities were also investigated by the photodegradation of methylene blue (MB) as a model molecule.
Effect of Penicillin G Potassium Salt on the Physicochemical Properties of SDS Aqueous Solution and the Release of the Salt in SDS/n‐C5H11OH/H2O System
Authors: Qian Jun‐Hong , Lu Yi‐Ying , Guo Rong
Published: January 2006

The effects of penicillin potassium salt (PenK) on the solubility, Krafft temperature TK, critical micelle concentration CMC of SDS micelle and the phase behavior of SDS/n‐C5H11OH/H2O system were studied. The partial phase diagrams of SDS/PenK/H2O system at different temperatures were determined. The release amounts of PenK in SDS/n‐C5H11OH/H2O system and the distribution coefficient of PenK between micelle and water were measured by UV‐Vis spectroscopy. The results show that in the presence of PenK, the CMC of SDS was decreased while the TK of SDS was increased and the solubility of SDS in both water and SDS/n‐C5H11OH/H2O oil in water (O/W) microemulsion was decreased, but increased in water in oil (W/O) microemulsion. SDS micelles and SDS/n‐C5H11OH/H2O O/W microemulsion could accelerate the release rate of PenK. The addition of SDS and water could both increase the release rate of PenK, whereas the presence of n‐C5H11OH reduced the release rate of PenK. The above results were related to the electrostatic repulsion between PenK and SDS.
Kinetic Investigation of Thermal Decomposition Reactions of Podophyllotoxin and Its Derivatives
Authors: Wen Pu‐Hong , Feng Guo‐Dong , Zheng Jian‐Bin
Published: January 2006

The thermal behavior and thermal decomposition kinetic parameters of podophyllotoxin (1) and 4 derivatives, picropodophyllin (2), deoxypodophyllotoxin (3), β‐apopicropodophyllin (4), podophyllotoxone (5) in a temperature‐programmed mode have been investigated by means of DSC and TG‐DTG. The kinetic model functions in differential and integral forms of the thermal decomposition reactions mentioned above for first stage were established. The kinetic parameters of the apparent activation energy Ea and per‐exponential factor A were obtained from analysis of the TG‐DTG curves by integral and differential methods. The most probable kinetic model function of the decomposition reaction in differential form was (1−α)2 for compounds 1–3, (2/3)·α−1/2 for compound 4 and (1/2)(1−α)·[−ln (1−α)]−1 for compound 5. The values of Ea indicated that the reactivity of compounds 1–5 was increased in the order: 5<4<2<1<3. The values of the entropy of activation ΔS≠, enthalpy of activation ΔH≠ and free energy of activation ΔG≠of the reactions were estimated. The values of ΔG≠indicated that the thermal stability of compounds 1–3with the same f(α) was increased in the order: 2<3<1.
Effects of Ultrasonic Treatment on the Structure and Electrochemical Performances of Spherical β‐Ni(OH)2
Authors: Zhou Huan‐Bo , Zhou Zhen‐Tao
Published: January 2006

A method of ultrasonic treatment (UST) was first used to modify the structure and electrochemical performance of nickel hydroxide for the active material of nickel series alkaline batteries. The experimental results showed that UST was an effective method to improve the electrochemical performance of β‐Ni(OH)2such as specific discharge capacity, discharge potential, electrochemical reversibility and oxygen evolution over‐potential. The results of electrochemical impedance spectroscopy, powder X‐ray diffraction and particle size distribution indicated that the improvement of the performance of β‐Ni(OH)2 through UST was attributed to the reduction of the charge‐transfer resistance (Rt) and the diffusion impedance (Zw), which resulted from the decrease of the crystallite and particle size and the increase of interlayer spacing. Diffusion coefficient of proton DH of ultrasonic treated β‐Ni(OH)2gained by CV tests was 1.13×10−11cm2/s, and the average discharge specific capacity of ultrasonic treated β‐Ni(OH)2 electrode was 301 mAh/g.
Antimicrobial Properties and Toxicity of Anthraquinones by Microcalorimetric Bioassay
Authors: Wu Yan‐Wen , Ouyang Jie , Xiao Xiao‐He , Gao Wen‐Yuan , Liu Yi
Published: January 2006

The growth thermogenic curves of Staphylococcus aureus and Tetrahymena thermophila affected by 1,8‐dihydroxyanthraquinone, emodin and rhein were determined quantitatively by microcalorimetry. The inhibitory effects of the three anthraquinones (AQ) on S.aureus revealed that the sequence of antimicrobial activity of those was rhein>emodin>1,8‐dihydroxyanthraquinone. The toxicity of the three AQ on T. thermophila indicated that all the tested AQ were toxic to the tested protozoa and the hydroxyl and carboxyl substituted at different position of anthraquinone ring resulted in the enhancement of toxicity.
Linear Expression of the Mathematical Relationship between Electroosmotic Mobility and Buffer Concentration
Authors: Xu Xu , Gao Jian‐Ping , Bao Xiao‐Ling
Published: January 2006

It was believed that electroosmotic mobility μeo is inversely proportional to the square root of the ionic strength I. But the linear relationship for regression analysis was expressed differently in different papers. The paper studied the linear expression of the mathematical relationship between μeo and c (background buffer concentration) by mathematical transform and real experimental data. μeo values of fused silica capillary were determined in four buffer systems. Their experimental conditions were controlled carefully for decreasing temperature difference ΔT and pH difference ΔpH in 50 µm ID capillary, in which no double layer overlap existed. The linear relationship between the reciprocal of electroosmotic mobility and the square root of concentration (or ionic strength) was derived by mathematical method. The regression analysis of experimental data was shown to well correspond to the relationship. The constants in regression equation could be well defined and the calculated results were acceptable.
Synthesis and Mesomorphic Properties of Chiral Mesogens Bearing Fluorinated Alkyl Terminal Tails
Authors: Qin Chuan , Rong Guo‐Bin , Chen Bao‐Quan , Wen Jian‐Xun
Published: January 2006

Ten chiral mesogenic compounds containing fluorinated alkyl terminal tails were prepared and characterized by IR, NMR, MS. The phase transition behavior was investigated by DSC and polarized optical microscope. Two‐ring liquid crystal compounds exhibited no mesogenic phase or only a monotropic smectic A phase. The longer fluorinatd alkyl chain on the three‐ring was advantageous to the formation of smectic phase. The mesogens with chiral center located between fluorinated tail and mesogenic core exhibited chiral smectic C phase and other smectic phases when the alkoxyl adhering to the other side of the mesogenic core was of intermediate length.
Evaluation of complete disease remission in acute myeloid leukemia
Authors: Bacher Ulrike , Kern Wolfgang , Schoch Claudia , Schnittger Susanne , Hiddemann Wolfgang , Haferlach Torsten
Published: January 2006

BACKGROUND

Different diagnostic methods add information to define complete remission (CR) in patients with acute myeloid leukemia (AML). The detection of minimal residual disease (MRD) for predicting prognosis and for therapeutic planning still are under discussion.

METHODS

The authors studied 216 patients with AML at the time of initial diagnosis and during follow‐up and correlated cytomorphology, interphase fluorescence in situ hybridization (FISH), and flow cytometry results to evaluate response status. They further tested the prognostic impact of those results, especially in patients who achieved a morphologic CR.

RESULTS

Interphase FISH was found to be correlated significantly with the clinical course at the time of complete cytomorphologic remission and was more reliable than morphology for defining CR. Furthermore, interphase FISH was correlated with immunophenotyping results at all times during follow‐up.

CONCLUSIONS

The current results indicated that interphase FISH may be used as a valid MRD parameter in patients with AML. Multiparameter immunophenotyping for MRD also was correlated strongly with the clinical course, and the authors suggest integrating such immunophenotyping into the routine diagnostic panel at the time of diagnosis and during the clinical course in patients with AML. Cancer 2006. © 2006 American Cancer Society.
Phase III study of PSC‐833 (valspodar) in combination with vincristine, doxorubicin, and dexamethasone (valspodar/VAD) versus VAD alone in patients with recurring or refractory multiple myeloma (E1A95)
Authors: Friedenberg William R. , Rue Montserrat , Blood Emily A. , Dalton William S. , Shustik Chaim , Larson Richard A. , Sonneveld Pieter , Greipp Philip R.
Published: January 2006

BACKGROUND

Preliminary studies have shown valspodar (PSC‐833: Novartis Pharmaceuticals, East Hanover, NJ) to be a potent inhibitor of multidrug resistance (MDR), one cause of resistance to chemotherapy. An international randomized control study (Phase III) evaluated the use of vincristine, doxorubicin, and dexamethasone (VAD) with (n= 46) and without (n= 48) valspodar in the treatment of patients with recurring or refractory multiple myeloma.

METHODS

Patients with documented recurrence or refractory myeloma were stratified based on prior treatment exposure and creatinine and randomized. Because of interaction of valspodar with vincristine and doxorubicin, the doses of these drugs were reduced compared with the VAD‐alone arm, and the doxorubicin was further reduced in the last 15 patients when given with valspodar based on pharmacokinetic and toxicity studies.

RESULTS

There were no complete or near‐complete responses. There were 29% partial responses (PRs) in the VAD‐alone arm and 44% with valspodar (P= 0.2). Median progression‐free survival was 7 months with VAD alone and 4.9 months with valspodar (P= 0.50). Subjective response was 19% with VAD alone and 17% with valspodar (P= 1.0). Median survival with VAD alone was 18.5 months and 15.3 with the addition of valspodar (P= 0.055). Toxicity of Grade 3 or greater was higher (P< 0.0001) in the valspodar arm (89%) compared with the VAD‐alone arm (58%). The reduction of doxorubicin dose reduced toxicity but not significantly (P= 0.11).

CONCLUSION

The addition of the MDR‐modulating agent valspodar to VAD did not improve treatment outcome. Toxicity was increased in the valspodar‐treated group compared with VAD alone. Cancer 2006. © 2006 American Cancer Society.
Adjuvant chemotherapy in muscle‐invasive bladder carcinoma
Authors: Ruggeri Enzo Maria , Giannarelli Diana , Bria Emilio , Carlini Paolo , Felici Alessandra , Nelli Fabrizio , Gallucci Michele , Cognetti Francesco , Pollera Camillo Francesco
Published: January 2006

BACKGROUND

The treatment of muscle‐invasive bladder carcinoma should include both the eradication of local disease and the elimination of potential micrometastases. To date, the ‘gold standard’ treatment for muscle invasive bladder carcinoma has been recognized to be radical cystectomy. Adjuvant chemotherapy (AC) has the advantage of being administered to patients with known prognostic factors of recurrence. A pooled analysis was used to verify whether AC is able to increase the disease‐free survival (DFS) and overall survival (OS) of patients with muscle‐invasive bladder carcinoma who had undergone radical cystectomy.

METHODS

All published randomized Phase III studies were considered eligible and a literature‐based pooled analysis was accomplished. DFS and OS were the endpoints. Event‐based relative risk ratio (RR) and 95% confidence intervals (95% CI) were derived. Combined effect estimation was computed with a fixed‐ and a random‐effect model. A heterogeneity test was applied as well.

RESULTS

Five trials were collected. All were evaluable for OS (350 patients) and four of these also were evaluable for DFS (273 patients). A significant benefit from AC was noted both in OS (RR, 0.74; 95% CI, 0.62–0.88 [P = 0.001]) and DFS (RR, 0.65; CI 0.54–0.78, [P < 0.001]). No significant heterogeneity was found.

CONCLUSIONS

Although the results of the analysis favor the use of AC, larger studies are needed to identify the role of AC in the treatment of muscle‐invasive bladder carcinoma. Ongoing trials (European Organization for Research and Treatment of Cancer [EORTC]/Southwest Oncology Group [SWOG] and the Italian Multicentric Study) can help to better identify patients who can benefit from this approach. Cancer 2006. © 2006 American Cancer Society.
Optimal integrated code generation for VLIW architectures
Authors: Kessler Christoph , Bednarski Andrzej
Published: January 2006

We present a dynamic programming method for optimal integrated code generation for basic blocks that minimizes execution time. It can be applied to single‐issue pipelined processors, in‐order‐issue superscalar processors, VLIW architectures with a single homogeneous register set, and clustered VLIW architectures with multiple register sets. For the case of a single register set, our method simultaneously copes with instruction selection, instruction scheduling, and register allocation. For clustered VLIW architectures, we also integrate the optimal partitioning of instructions, allocation of registers for temporary variables, and scheduling of data transfer operations between clusters. Our method is implemented in the prototype of a retargetable code generation framework for digital signal processors (DSPs), called OPTIMIST. We present results for the processors ARM9E, TI C62x, and a single‐cluster variant of C62x. Our results show that the method can produce optimal solutions for small and (in the case of a single register set) medium‐sized problem instances with a reasonable amount of time and space. For larger problem instances, our method can be seamlessly changed into a heuristic. Copyright © 2006 John Wiley & Sons, Ltd.
Parametric timing estimation with Newton–Gregory formulae
Authors: van Engelen Robert A. , Gallivan Kyle A. , Walsh Burt
Published: January 2006

This paper presents a novel method for parametric worst‐case execution time (WCET) estimation of loops. The method determines a parametric bound on the iteration space size of loops with both affine and non‐affine loop bounds in an efficient manner using a formulation based on Newton–Gregory interpolating polynomials. Parametric WCET formulae are used to support dynamic scheduling decisions at runtime, where the WCET of a scheduled task might not be known statically. To determine worst‐case execution time estimates of scientific and multimedia codes, which spent most of the execution time on executing loop iterations, efficient and accurate symbolic loop WCET estimation methods must be capable of analyzing loops with symbolic bounds, non‐rectangular loops, zero‐trip loops, loops with multiple critical paths, and loops with non‐unit strides. Copyright © 2006 John Wiley & Sons, Ltd.
Club theory of the Grid
Authors: Shi Yao , Lau Francis C. M. , Tse Savio S. H. , Du Zhi‐Hui , Tang Rui‐Chun , Li San‐Li
Published: January 2006

The Grid is a new type of resource sharing infrastructure. Due to software and hardware limitations, the service that a certain Grid can offer is finite, and so is the number of users it can accommodate. If the number of users is too small, much of the planned resources would be wasted. On the other hand, excessive loading due to too many users could substantially reduce the benefit enjoyed by each user and also the efficiency of the Grid service. Therefore, there are two main problems for Grid design. (1) How many users should the Grid serve so that each user can receive the maximum benefit? (2) To a certain group of users, how much resources should be invested so that the construction and maintenance of the Grid become viable? Based on the economic theory of clubs, this paper gives a quantitative analysis of the quasi‐optimal number of users and amount of each resource by regarding Grid services and resources as club goods. Based on our assumptions on the system model, we deduce two preliminary results and verify them by experiments using GridFTP. These two results allow the users to run randomized algorithms to achieve better system performance. Copyright © 2006 John Wiley & Sons, Ltd.
Membrane Calculus: a formal method for Grid transactions
Authors: Qi Zhengwei , Li Minglu , Fu Cheng , Shi Dongyu , You Jinyuan
Published: January 2006

The research of transaction processing in Web Services and Grid Services is active in academic and engineering areas. However, the formal method of transaction processing has not been fully investigated in the literature. This paper proposes a preliminary theoretical model called Membrane Calculus based on Membrane Computing and Petri nets to formalize Grid transactions. Five kinds of transition rules in Membrane Calculus (including object rules and membrane rules) are introduced and the operational semantics of transition rules are defined. Then, a typical long‐running transaction example is presented to demonstrate the use of Membrane Calculus. Finally, the rewriting logic tool Maude is adopted to specify and execute the specification of this example. Copyright © 2006 John Wiley & Sons, Ltd.
De‐centralized job scheduling on computational Grids using distributed backfilling
Authors: Wang Qingjiang , Gui Xiaolin , Zheng Shouqi , Liu Yang
Published: January 2006

To dynamically improve system selections of the waiting jobs under de‐centralized scheduling frameworks, each computation system together with its neighbors is assumed to compose a subgrid, and distributed backfilling is proposed as the scheduling strategy in each subgrid. Whenever a job terminates, distributed backfilling is triggered to re‐backfill all waiting jobs on the corresponding subgrid in order of their submittal. Each subgrid is overlapped with another, so the waiting jobs may be migrated around the Grid. To evaluate distributed backfilling, Grid resources and scheduling framework are configured, the model of Grid workload is constructed by extending the workload models of parallel systems and the Job Scheduling Simulation System is designed to simulate the process of de‐centralized job scheduling. In addition, job speedup is presented as performance metrics of scheduling strategies. Results show the dynamic optimization of system selections brought by distributed backfilling is Grid‐wide, and can improve scheduling performance remarkably as long as Grid load is not too light and the job migration costs are not too high. Copyright © 2006 John Wiley & Sons, Ltd.
Trust‐based probabilistic search with the view model of peer‐to‐peer networks
Authors: Zhuge Hai , Chen Xue , Sun Xiaoping
Published: January 2006

The fundamental challenge confronting peer‐to‐peer (P2P) resource‐sharing networks is to provide efficient and scalable search services in a large‐scale, open and dynamic environment. However, current search mechanisms are not efficient or scalable enough with the expansion of the systems. To improve search efficiency, this paper proposes the trust‐based probabilistic search mechanism, called the Preferential Walk (P‐Walk). Every peer adjusts its neighbors' rank continuously according to their performance in previous searches. The basic principle of the P‐Walk is that neighbors with higher ranks in the question domain have higher probabilities of being queried. Extensive simulation results show that the P‐Walk can significantly improve the success rate of the query and the response time whilst also effectively reducing traffic volume and controlling malicious behavior. Furthermore, we measure the rank distributions of the peers and find their power‐law‐like trends based on a Gnutella‐like network. Implications are drawn from the analysis of the rank distributions. The P‐Walk mechanism works effectively in a P2P view model that provides appropriate views of the P2P network for queries of different types. Copyright © 2006 John Wiley & Sons, Ltd.
Components and workflow based Grid programming environment for integrated image‐processing applications
Authors: Jin Hai , Zheng Ran , Zhang Qin , Li Ying
Published: January 2006

With the development of high‐performance computing technologies, Grid computing has emerged as a new infrastructure for applications with resource integration. However, some obstacles for the prevalence of Grid and Grid application developments are still to be overcome, which is largely due to the immature Grid‐enabled computing environment and its geographically distributed and non‐centralized administrative nature. In order to improve the situation and support Grid applications, a powerful Grid system is proposed as an efficient solution, which enables components and workflow support for loosely coupled and geographically distributed components on a Grid. An image‐processing Grid is a project aiming at providing an efficient programming environment. In this paper, we discuss the infrastructure of the integrated environment, a flexible and useful workflow mechanism, a dynamic resource‐scheduling strategy to achieve multiple image‐processing operations, and an easy‐to‐use Web portal. In the system, components and workflow techniques provide the benefits of flexibility, reusability and scalability, so that even the unskilled user can easily specify the processing of complex, cooperative applications without knowledge of underlying Grid platform configuration details. Copyright © 2006 John Wiley & Sons, Ltd.
MOVPE growth of GaAs on Ge substrates by inserting a thin low temperature buffer layer
Authors: Scholz S. , Bauer J. , Leibiger G. , Herrnberger H. , Hirsch D. , Gottschalch V.
Published: January 2006

High quality GaAs layers have been grown by low pressure MOVPE on Ge(001) and Ge(001) 9° off oriented in [110] direction by using a thin low temperature (LT) GaAs layer. Investigations of the initial growth step were performed at different V/III ratios and temperatures. To show the good buffer layer quality solar cell structures were grown on off oriented n‐Ge(001) and n‐GaAs(001) substrates. The surface morphology was studied by atomic force microscopy which showed the step‐flow growth mode on 1.2 µm thick GaAs/Ge structures. The crystalline qualities of this structures and the smooth surface morphology were investigated by double crystal X‐ray diffraction (XRD) and atomic force microscopy (AFM). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of big single crystals of a new magnetic superconducting double perovskite Ba2PrRu1–xCuxO6
Authors: Rao S. M. , Wu M. K. , Srivastava J. K. , Mok B. H. , Chou T. W. , Lu C. Y. , Ling M. C. , Liu H. L. , Liao Y. C.
Published: January 2006

Single crystals of Ba2PrRu1–xCuxO6 with x = 0 to 0.2, have been grown from high temperature solutions of a mixture of PbO‐PbF2 in the temperature range 1100–1200 °C. Thin crystals with mostly a hexagonal and triangular plate like habit measuring up to 1–2 mm across and 0.1–0.2 mm thick were obtained. The size, quality and morphology of the crystals were improved by varying the solution volume as well as additives like B2O3. Large crystals measuring up to 3 mm across and 0.3 to 0.5 mm thick were obtained with 5–7 wt% solute concentration and 0.51 wt% of B2O3. The ZFC curves exhibit a spin glass like behavior with x = 0 and a superconducting transition at 8 to 11 K depending on x = 0.05 to 0.1. The transition was also influenced by the growth temperature and post growth annealing. Powder x‐ray diffraction, EDS and Raman spectroscopic measurements confirm the presence of Cu in the crystals. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of nanosized ZSM‐5 using different alumina sources
Authors: Ismail A. A. , Mohamed R. M. , Fouad O. A. , Ibrahim I. A.
Published: January 2006

Alumina sources can influence different aspects of ZSM‐5 crystallization and it leads to change in the properties of the final product. The crystallinity of nanosized ZSM‐5 zeolite from precursors mixtures containing different alumina sources, e.g. sodium aluminate, aluminum sulphate, aluminum hydroxide and alumina has been studied. The produced samples were investigated using XRD, SEM, FT‐ IR and BET surface area. The product obtained by sodium aluminate and aluminum sulphate was ZSM‐5 phase. Whereas, the product obtained by aluminum hydroxide and alumina was the albit phase. As‐synthesized ZSM‐5 was prepared by sodium aluminate, as alumina source was the highest crystallinity. It was found that the average crystallite size increased in the following order; alumina <aluminum hydroxide < aluminum sulphate < sodium aluminate. The surface area increased in the following order; aluminum sulphate < sodium aluminate < aluminum hydroxide < alumina due to increasing in crystallinity percentage of ZSM‐5. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical properties of vapour‐etching based porous silicon
Authors: Kaabi H. , Mliki N. , Cheynet M. , Saikaly W. , Gilbert O. , Bessaïs B. , Yangui B. , Charaï A.
Published: January 2006

The structural and optical properties of porous silicon (PS) layers prepared by Vapour‐Etching (VE) of moderately and heavily boron‐doped Si substrates are investigated. The VE technique produces rough PS layers that are essentially formed of interconnected cluster‐like structures. Optical investigations indicate that this surface roughness enables the PS layers to be used as antireflection coatings in silicon based devices. These optical characteristics are investigated by optical reflectivity and light scattering. The local chemical state and the microstructure of the PS layers are studied by electron energy loss spectroscopy (EELS) in transmission electron microscopy (TEM), and are correlated to the red photoluminescence (PL). TEM studies point out that the cluster‐like interconnected structures are composed of luminescent nanocrystallites. PL measurements display that both quantum confinement and surface passivation determine the electronic states of the silicon nanocrystallites. The complex dielectric function is calculated from the experimental single‐scattering distribution spectrum using a Kramers Kronig analysis. The first resonance peak in the imaginary part is observed at 2.3 eV; two other broadened features appear at 4.7 and 8.8 eV. The latter is generally related to an interface plasmon resulting from the silicon‐silicon oxide interface. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of chemical‐mechanical polishing for planarizing of silicon nitride passivation layers used in high power III‐V laser devices
Authors: Wei Jiang
Published: January 2006

Chemical‐mechanical polishing (CMP) allows the planarization of wafers with thin layer at its surface. Subject of this investigation was to apply CMP for planarizing silicon nitride (Si3N4) passivation layer in high power III‐V laser devices, which remained in the structure as the insulation and planarization layer. For planarizing a nitride layer, oxide CMP slurry was used in conjunction with standard CMP polishing pads. Since III‐V materials, such as GaAs and InP, are very soft and fragile, the CMP process must be well controlled to avoid the ridge crack. The optimum CMP conditions have been presented in the paper, which gave the desirable surface quality. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal structure analysis of {[μ‐N,N′‐Bis(salicylidene)‐1,3‐propanediaminato]nickel(II)}dichloromercury(II)
Authors: Arįcį C. , Ülkü D. , Atakol O. , Tahir M. N.
Published: January 2006

The title compound, a hetero‐dinuclear complex with Ni(II) and Hg(II) ions, forms crystals which belong to the triclinic system, space group P1, with unit cell dimensions a = 8.9620(12), b = 9.2370(11), c = 12.0810(13) Å, α = 92.100(3)° , β = 105.317(5)°, γ = 110.502(3)°, V = 894.2(2) Å3. The cell contains two molecules. The Ni…Hg distance is 3.4859(7) Å. The distance Hg...Hga (symmetry code: ‐x,‐y,‐z) between the neighbouring molecules is 4.7514(7) Å. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrasonic particle‐concentration for sheathless focusing of particles for analysis in a flow cytometer
Authors: Goddard Gregory , Martin John C. , Graves Steven W. , Kaduchak Gregory
Published: January 2006

Background:

The development of inexpensive small flow cytometers is recognized as an important goal for many applications ranging from medical uses in developing countries for disease diagnosis to use as an analytical platform in support of homeland defense. Although hydrodynamic focusing is highly effective at particle positioning, the use of sheath fluid increases assay cost and reduces instrument utility for field and autonomous remote operations.

Methods:

This work presents the creation of a novel flow cell that uses ultrasonic acoustic energy to focus small particles to the center of a flowing stream for analysis by flow cytometry. Experiments using this flow cell are described wherein its efficacy is evaluated under flow cytometric conditions with fluorescent microspheres.

Results:

Preliminary laboratory experiments demonstrate acoustic focusing of flowing 10‐μm latex particles into a tight sample stream that is ∼40 μm in diameter. Prototype flow cytometer measurements using an acoustic‐focusing flow chamber demonstrated focusing of a microsphere sample to a central stream ∼40 μm in diameter, yielding a definite fluorescence peak for the microspheres as compared with a broad distribution for unfocused microspheres.

Conclusions:

The flow cell developed here uses acoustic focusing, which inherently concentrates the sample particles to the center of the sample stream. This method could eliminate the need for sheath fluid, and will enable increased interrogation times for enhanced sensitivity, while maintaining high particle‐analysis rates. The concentration effect will also enable the analysis of extremely dilute samples on the order of several particles per liter, at analysis rates of a few particles per second. Such features offer the possibility of a truly versatile low‐cost portable flow cytometer for field applications. © 2005 Wiley‐Liss, Inc.
Static magnetic fields affect cell size, shape, orientation, and membrane surface of human glioblastoma cells, as demonstrated by electron, optic, and atomic force microscopy
Authors: Teodori Laura , Albertini Maria C. , Uguccioni Francesco , Falcieri Elisabetta , Rocchi Marco B. L. , Battistelli Michela , Coluzza Carlo , Piantanida Giovanna , Bergamaschi Antonio , Magrini Andrea , Mucciato Raffaele , Accorsi Augusto
Published: January 2006

Background:

It is common knowledge that static magnetic fields (SMF) do not interact with living cells; thus, fewer studies of SMF compared with variable magnetic fields are carried out. However, evidence demonstrated that SMF affect cellular structures. To investigate the effect of exposure to increasing doses of SMF on cell morphology, human glioblastoma cells were exposed to SMF ranging between 80 and 3,000 G (8 and 300 mT).

Methods:

Cell morphology of human glioblastoma cells, derived from a primary culture, was studied by electron and optic microscopy. FITC‐phalloidin staining of actin filaments was also investigated. Finally, cell surface structure changes were detected by atomic force microscopy.

Results:

Scanning electron microscopy demonstrated a dose‐dependent cell shape modification, progressive cell detachment, loss of the long villi, and appearance of membrane roughness and blebs. FITC‐phalloidin staining confirmed the villi retention and cell dimension decrease. At 3,000 G, the appearance of apoptotic morphology was also observed by transmission electron microscopy. Cell exposed to SMF showed different orientation and alignment when compared with nonexposed cells. The atomic force microscopy of the exposed cells' membrane surfaces demonstrated the disappearance of the ordered surface ripples and furrows typical of the unexposed cells, and the occurrence of surface membrane corrugation at increasing dose exposure

Conclusions:

Our experimental procedures demonstrated that exposure to SMF affects not only cell size, shape, and orientation but also human glioblastoma cells' membrane surfaces. © 2005 Wiley‐Liss, Inc.
Synthesis of Pulvinic Acid and Norbadione A Analogues by Suzuki–Miyaura Cross‐Coupling of Benzylated Intermediates
Authors: Desage‐El Murr Marine , Nowaczyk Stéphanie , Le Gall Thierry , Mioskowski Charles
Published: January 2006

Pulvinic acid and norbadione A analogues can be prepared by Suzuki–Miyaura cross‐coupling of functionalized arylboronic esters with appropriate vinyl triflates, in which the hydroxy functions are protected either with methyl or benzyl groups, the latter being cleaved in a more reliable fashion at the end of the synthetic sequence. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Voltammetry of Metallic Powder Suspensions on Mercury Electrodes
Authors: Korshunov Andrey V. , Heyrovský Michael
Published: January 2006

Ultrafine powder samples of Cu, Fe, Ni, Mo and W were examined voltammetrically in aqueous suspensions with hanging mercury drop electrode. According to chemical interaction of the metallic powder particles with the dispersing medium the voltammetric curves either consist of a set of individual current peaks given by particulate reduction of surface oxides on impingements of particles from their suspension upon the electrode, or correspond to electroactivity of dissolved products of chemical reaction between particles and the medium.
Development of an Amperometric Enzymatic Biosensor Based on Gold Modified Magnetic Nanoporous Microparticles
Authors: Elyacoubi Abdeslam , Zayed Sayed I. M. , Blankert Bertrand , Kauffmann Jean‐Michel
Published: January 2006

Gold modified nanoporous silica based magnetic microparticles have been prepared as support for the immobilization of the enzyme horseradish peroxidase (HRP). The enzyme modified gold microparticles were retained onto the surface of a solid carbon paste electrode with the help of a permanent magnet. The analytical performances of the resulting biosensor were characterized by studying hydroquinone (HQ) and hydrogen peroxide. The former was monitored by the direct electroreduction of the biocatalytically generated quinone. Several experimental parameters influencing the biosensor response were investigated. A linear response to HQ was obtained in the concentration range comprised between 5×10−7 and 4.5×10−6 M with a detection limit of 4×10−7 M. The enzyme electrode provided a linear response to hydrogen peroxide over a concentration range comprised between 5×10−7−1.3×10−4 M with a detection limit of 4×10−7 M. The inhibition of the biosensor response in the presence of thiols e.g. cysteine, captopril, glutathione and Nacystelyn (NAL) has been pointed out.
Double‐Layer Correction for Electron‐Transfer Kinetics at Glassy Carbon and Mercury Electrodes in N,N‐Dimethylformamide
Authors: Belèn Meneses Ana , Antonello Sabrina , Arévalo Maria Carmen , Maran Flavio
Published: January 2006

The double‐layer properties of the glassy carbon electrode in N,N‐dimethylformamide (DMF) containing tetrabutylammonium perchlorate (TBAP) at different concentrations have been studied by cyclic voltammetry and impedance. The results were compared with analogous results obtained for the mercury/DMF interface. For both electrodes, the double‐layer data were treated to obtain useful equations describing the dependence of the outer Helmholtz plane potential on the applied potential. The kinetics of the dissociative reduction of a sulfide in DMF/0.1 M TBAP was studied by convolution analysis on both glassy carbon and mercury and used as an example to test the double‐layer results and compare the behavior of the two electrodes.
Chromosomal fragile sites FRA3B and FRA16D show correlated expression and association with failure of apoptosis in lymphocytes from patients with thyroid cancer
Authors: Sbrana Isabella , Veroni Franca , Nieri Maria , Puliti Aldamaria , Barale Roberto
Published: January 2006

It has been suggested that common fragile sites (cFSs) are related to cancer development. This appears to be the case for FRA3B and FRA16D, localized in two tumor‐suppressor genes (FHIT and WWOX, respectively) that are altered by deletions or loss of heterozygosity (LOH) in many cancers. The features responsible for fragility have not yet been identified. Furthermore, it is still unclear whether instability at these regions causes chance deletions and loss of function of the associated genes, or whether the gene function itself is related to the appearance of fragility. In this study, we analyzed cFS expression in lymphocytes from 20 healthy or thyroid cancer–affected subjects exposed to radiation after the Chernobyl accident. The same cells were examined for apoptosis, a principal function of both the FHIT and WWOX genes. Exceptionally elevated chromosome fragility was observed, particularly in cancer patients, affecting FRA3B, FRA16D, and a cluster of less highly expressed cFSs; levels of chromosome fragility were found to be correlated among these cFSs. Interestingly, most expressed cFSs were sites of LOH reported for thyroid tumors; moreover, cells with the highest fragility also had a reduced ability to undergo apoptosis. These findings reveal previously unknown genetic interactions affecting fragile loci, suggestive of a shared function inside mitotic cells. Attenuation of checkpoint control and apoptosis resistance seem to be the cell phenotypes associated with unusual chromosome fragility. We propose that breakage at specific cFS could derive from early epigenetic events at loci involved in radiation carcinogenesis. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat. © 2006 Wiley‐Liss, Inc.