bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: Fused Heterocyclic Systems with s‐Triazine Ring. Part 8. Practical Synthesis of Regioisomeric 5(7)‐Amino‐6,7(4,5)‐dihydro[1,2,4]triazolo[1,5‐a][1,3,5]triazines.
Authors: Dolzhenko Anton V. , Dolzhenko Anna V. , Chui Wai‐Keung
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Palladium‐Catalyzed Intramolecular C—O Bond Formation: An Approach to the Synthesis of Chiral Benzodioxocines.
Authors: Neogi Arpita , Majhi Tirtha P. , Achari Basudeb , Chattopadhyay Partha
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Tetrazole Analogues of Aspartic, Glutamic and α‐Aminoadipic Acids and Their Derivatives with Tetrazole Ring in Side Chains Useful for Solid‐Phase Peptide Synthesis
Authors: Manturewicz M. , Grzonka Z.
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Highly Efficient Total Synthesis of the Marine Natural Products (+)‐Avarone (Ia), (+)‐Avarol (Ib), (‐)‐Neoavarone (IIa), (‐)‐Neoavarol (IIb) and (+)‐Aureol (III).
Authors: Sakurai Junji , Oguchi Takamasa , Watanabe Kazuhiro , Abe Hideki , Kanno Syu‐ichi , Ishikawa Masaaki , Katoh Tadashi
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Actinoperylone, a Novel Perylenequinone‐Type Shunt Product, from a Deletion Mutant of the actVA‐ORF5 and ORF6 Genes for Actinorhodin Biosynthesis in Streptomyces coelicolor A3(2).
Authors: Taguchi Takaaki , Okamoto Susumu , Itoh Takayuki , Ebizuka Yutaka , Ochi Kozo , Ichinose Koji
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A Convenient Synthesis of 2‐Formyl‐1,8:4,5‐bis(methylenedioxy)naphthalene.
Authors: Zhao Ai‐Hong , Xu De‐Feng , Zhuo Wen , Rao Zhen , Li Shao‐Shun
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Fusaripyrones, Novel Polypropionates from the Mediterranean Mollusc Haminoea fusari
Authors: Cutignano Adele , Blihoghe Daniela , Fontana Angelo , Villani Guido , d'Ippolito Giuliana , Cimino Guido
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Molecular Modeling and Mutagenesis Reveals a Tetradentate Binding Site for Zn2+ in GABAA αβ Receptors and Provides a Structural Basis for the Modulating Effect of the γ Subunit.
Authors: Trudell James R. , Yue Minerva E. , Bertaccini Edward J. , Jenkins Andrew , Harrison Neil L.
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Use of 3D QSAR Models for Database Screening: A Feasibility Study.
Authors: Hillebrecht Alexander , Klebe Gerhard
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: MMM‐QSAR Recognition of Ribonucleases Without Alignment: Comparison with an HMM Model and Isolation from Schizosaccharomyces pombe, Prediction, and Experimental Assay of a New Sequence.
Authors: Aguero‐Chapin Guillermin , Gonzalez‐Diaz Humberto , de la Riva Gustavo , Rodriguez Edrey , Sanchez‐Rodriguez Aminael , Podda Gianni , Vazquez‐Padron Roberto I.
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Al—Pd—Re (Aluminum—Palladium—Rhenium)
Authors: Raghavan V.
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Al—Mn—Pd (Aluminum—Manganese—Palladium)
Authors: Raghavan V.
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Al—C—Co (Aluminum—Carbon—Cobalt)
Authors: Raghavan V.
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Coordination of Buckybowls: The First Concave‐Bound Metal Complex
Authors: Petrukhina Marina
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Silver(I) Salts as Useful Reagents in Pyrazole Synthesis
Authors: Molteni Giorgio
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Rapid Syntheses of Biologically Active Quinazolinone Natural Products Using Microwave Technology
Authors: Liu Ji‐Feng
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Fluorine in Medicinal Chemistry
Authors: Purser Sophie , Moore Peter R. , Swallow Steve , Gouverneur Veronique
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Indolizidine and Quinolizidine Alkaloids
Authors: Michael Joseph P.
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Gas Phase Reaction Kinetics at very Low Temperatures: Recent Advances on Carbon Chemistry Using the CRESU Technique
Authors: Canosa A.
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: (+)‐Discodermolide: Total Synthesis, Construction of Novel Analogues, and Biological Evaluation
Authors: Smith Amos B. III , Freeze B. Scott
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: In silico‐Aided Prediction of Biological Properties of Chemicals: Oestrogen Receptor‐Mediated Effects
Authors: Roncaglioni Alessandra , Benfenati Emilio
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Recent Advances in NMR Studies of Cyclophanes
Authors: Ernst Ludger
Published: April 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Wandern auf dem Mond und auf anderen extraterrestrischen Himmelskörpern
Authors: Pawlowski J. , Zlokarnik M.
Published: April 2008

In dieser Arbeit wird aufgezeigt, dass es möglich ist, mittels der dimensionsanalytischen Auswertung von Messungen, die in einem stationären terrestrischen Labor gewonnen wurden, theoretisch begründete Aussagen über das Gehverhalten auf anderen Himmelskörpern, also bei anderen g‐Werten, zu gewinnen. Die Laboruntersuchungen dienen dabei als Modellversuche für extraterrestrisches Gehen und sind deshalb sowohl für die Belange der Raumfahrt als auch für die extraterrestrische Physiologie von großer Bedeutung. Was sich zunächst als eine interessante Anwendung der Dimensionsanalyse und Modelltheorie ansieht, erweist sich in nachhinein als eine elegante Methode, bedeutende Aussagen für die Raumfahrt zu gewinnen.
Cerebral Hemorrhage: Precipitating Event for a Tako‐tsubo‐like Cardiomyopathy?
Authors: Rahimi Ali R. , Katayama Masanobu , Mills Jacob
Published: April 2008

There have been some reports in medical literature of patients with profound, reversible left‐ventricular (LV) dysfunction after sudden emotional stress. Originally, in Japan, the pattern was called tako‐tsubo cardiomyopathy. ST‐segment elevation is seen with this syndrome, and it may look like acute ST‐elevation myocardial infarction. However, it has also been well established that a subarachnoid hemorrhage can manifest with cardiac abnormalities. The authors describe a case involving a cerebral hemorrhage and a potential tako‐tsubo‐like cardiomyopathy in the same patient. In conclusion, even though the patient's presentation appears to be a tako‐tsubo syndrome, the radiographic evidence of a cerebral hemorrhage presents as a stronger etiology for the cardiac changes that occur in our patient. Copyright © 2008 Wiley Periodicals, Inc.
Automation and validation of a rapid method to assess neutrophil and monocyte activation by routine fluorescence flow cytometry in vitro
Authors: Linssen J. , Aderhold S. , Nierhaus A. , Frings D. , Kaltschmidt C. , Zänker K.
Published: April 2008

The aim of the present study was to design an automated‐gating hematology fluorescence flow cytometry methodology permitting the assessment of neutrophil and monocyte activation in EDTA‐anticoagulated whole blood based on cell granularity, lipid membrane components, cell shape and volume, and total cell nucleic acid (NA) compounds. For particularly monitoring the proper functioning of patients' innate immune system as the first line defense against microbial invaders, the suitable test system should be rapid, simple, reliable by yielding reproducible results. It must be validated against established methods, and it must prove to work in selected clinical settings, e.g. in intensive care unit (ICU) environments.

The adaptation of a routine hematology cell analyser utilizing fluorescence flow cytometry resulted in a potentially useful system for all requirements. It proved to detect in real‐time and in a reliable and reproducible way the main cellular response reactions of neutrophils and monocytes during externally stimulated immune defense. Validation was successful when comparing it to established methods. The quantified activation effects were dose dependent from the applied activating agents. Cellular response kinetics could be measured and described and showed to be in line with the prevailing cell response models.

Upon applying the test method to a healthy population of volunteers and a first cohort of ICU patients with and without evident immune depression, the test revealed excellent cellular responses to external activating cytotoxic stimuli (lipopolysaccharide; LPS) for the control group, slightly weaker response from ICU patients without immune depression and no response from patients with evident immune depression.

We conclude that routine hematology fluorescence flow cytometry can accurately and reproducibly measure different activation steps of monocytes and polymorphonuclear neutrophilic granulocytes to defined external stimuli. This may potentially be applied as a STAT (Latin statim = immediately) and routine screening and surveillance method for inflammatory diseases. © 2008 Clinical Cytometry Society
Immunophenotypic features distinguishing familial chronic lymphocytic leukemia from sporadic chronic lymphocytic leukemia
Authors: Ahmad Ejaz , Steinberg Seth M. , Goldin Lynn , Hess Christopher J. , Caporaso Neil , Kreitman Robert J. , Wiestner Adrian , Wilson Wyndham , White Therese , Marti Gerald , Stetler‐Stevenson Maryalice
Published: April 2008

Background

Familial chronic lymphocytic leukemia (CLL) has the most frequent familial aggregation among hematological malignancies. Familial CLL families have been studied to identify susceptibility genes and other factors that contribute in the etiology of CLL. To date no study has been conducted to evaluate and compare patterns of cell surface antigen expression in familial CLL and sporadic CLL.

Methods

The pattern of cell surface antigen expression was studied in familial and sporadic CLL to determine if unique identifiers of familial CLL could be detected. Survival in familial CLL verses sporadic CLL was compared and the association between prognosis and CD38 expression studied.

Results

Familial and sporadic CLL demonstrated the same characteristic immunophenotype (positive for surface immunoglobulin, CD5, CD19, and CD23 with dim CD20, and CD22). CD2 and CD13 expression, however, were more frequent (30% of cases) in familial CLL (P = 0.0003 for CD2, P = 0.006 for CD13) than in sporadic CLL (2–6%). There was no significant difference in survival in the two groups studied. Although the incidence of CD38 expression was similar in familial and sporadic CLL (47% and 44% respectively) the association with prognosis differed. There was a trend to decreased survival in CD38 positive sporadic (P = 0.06) but not familial CLL patients.

Conclusions

We conclude that detection of CD2 or CD13 expression in CLL suggests familial CLL and examination of family history for additional affected members is warranted. Furthermore, CD38 expression does not carry the negative prognosis observed in sporadic CLL. Published 2008 Wiley‐Liss, Inc.
SPARC is expressed by macroglia and microglia in the developing and mature nervous system
Authors: Vincent Adele J. , Lau Patricia W. , Roskams A. Jane
Published: April 2008

Distribution of the matricellular protein, SPARC/osteonectin (green), in the dentate gyrus of the postnatal mouse. SPARC expression partially overlaps with the radial glial markers, nestin (red, top panel) and brain‐lipid binding protein (red, bottom panel; DAPI nuclear counterstain, blue). See Vincent et al., Developmental Dynamics 237:1449–1462, 2008. © 2008 Wiley‐Liss, Inc.
Estimation of load model parameters for harmonic analysis
Authors: Hayashi Yasuhiro , Matsuki Junya , Kobayashi Kenichi , Kanao Norikazu
Published: April 2008

In order to devise countermeasures for harmonic disturbances and harmonic suppression in power systems effectively, it is necessary to develop a harmonic analysis approach with high accuracy. The major harmonic analysis approach is to re‐create harmonic distribution in a power system model by using a simulation method. However, in order to carry out high‐accuracy estimation of the harmonic distribution using the simulation method, after creating a load model which consists of several parameters associated with the measured harmonic impedance, the optimal load model parameters must be determined. So far, appropriate load model parameters have been determined by trial and error. Therefore, a systematic approach to determine the optimal load model parameters is needed to estimate the measured harmonic impedance with high accuracy.

In this paper, a determination method for the optimal load model parameters to estimate the measured harmonic impedance is proposed. The proposed method is based on Particle Swarm Optimization (PSO), which is one of the optimization methods using the concept of swarm intelligence. In order to check the validity of the proposed method, the load model parameters estimated by the proposed method are evaluated using test data and field data of Hokuriku Electric Power Co. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(2): 44–53, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20415
A competitive evaluation of urban energy systems from viewpoints of energy conservation and mitigating environmental impact
Authors: Sugihara Hideharu , Tomioka Hajime , Tsuji Kiichiro
Published: April 2008

Although various energy system alternatives for business, commercial, and residential customers have recently been developed in order to reduce energy consumption and CO2 emission, it is important to evaluate competitive characteristics among such new energy system alternatives quantitatively, in consideration of tradeoff relations among economic cost, energy consumption, and CO2 emission. In this paper, using multiobjective optimization model for urban energy system planning, two competitive evaluations are performed. One is the break‐even cost analysis for introducing more efficient, but more expensive energy equipment, such as photovoltaic system and fuel cell system. The other is that we evaluate the competitiveness of a certain energy system from the viewpoint of a whole urban area because there are multiple alternatives for attaining the same target of reducing CO2 emission of energy consumption. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(2): 71–79, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20421
Interconnected power systems with superconducting magnetic energy storage
Authors: Nomura Shinichi , Hagita Takushi , Tsutsui Hiroaki , Sato Yoshihisa , Shimada Ryuichi
Published: April 2008

The objective of this work is to discuss the concept of back‐to‐back interconnection systems with energy storage, especially with a Superconducting Magnetic Energy Storage (SMES) incorporated into a back‐to‐back DC link. In this case, each converter of the back‐to‐back system is used as a power conditioning system for the SMES coils. Since the AC–DC converter can be designed independently of the frequency of the power system, a two‐way switch is connected to the AC side of each converter. This two‐way switch can select the interconnected power systems. By using the two‐way switches, this system can provide the stored energy in the SMES system to each interconnected power system through two AC–DC converters. For instance, lower‐cost power of each power network can be stored through two converters during the off‐peak hours and made available for dispatch to each power network during periods of demand peak. Then this system increases the reliability of electric power networks and enables the economical operations depending on the power demand. This paper describes the unique operations of the back‐to‐back interconnection with SMES and discuses the optimal SMES configuration for a 300‐MW‐class back‐to‐back interconnection. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(2): 37–43, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20482
Synthesis of Millimeter‐Range Orthorhombic V2O5 Nanowires and Impact of Thermodynamic and Kinetic Properties of the Oxidant on the Synthetic Process
Authors: Zhou Fu , Zhao Xuemei , Liu Yunqi , Yuan Cunguang , Li Li
Published: April 2008

Large‐scale orthorhombic V2O5 single‐crystalline nanowires with diameters of 60–80 nm and lengths into the millimeter range were synthesized through a facile template‐free, mild, and direct hydrothermal reaction between VOSO4·xH2O and KMnO4. The nanowires are nearly visible to the naked eye and are by far the longest 1D nanostructures of vanadium oxide ever fabricated. The impacts of the thermodynamic and kinetic properties of the oxidant were studied by parallel experiments by using different kinds of oxidants, and both were found to be crucial for the successful synthesis of the ultralong V2O5 nanowires.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Novel Addition Mechanism for the Reaction of “Frustrated Lewis Pairs” with Olefins
Authors: Guo Yong , Li Shuhua
Published: April 2008

Density functional theory calculations have been carried out to investigate the addition mechanism for the reactions of “frustrated Lewis pairs” with olefins. Several reactions are studied in this work, which include a three‐component reaction between a sterically demanding phosphane [P(tBu)3], borane [B(C6F5)3], and ethylene, and a two‐component reaction between an olefin derivative of phosphane [CH2=CH–(CH2)3P(tBu)2] and B(C6F5)3. For the two‐component reaction, we find a concerted addition mechanism, in which the formation of the B–C and P–C bonds takes place simultaneously. For the three‐component reaction, our calculations show that the reaction may be initiated by the weak association of B(C6F5)3 with ethylene (to form a transient species) and then proceeds in a concerted transition state similar to that in the two‐component reaction under study. The natural population analyses for the corresponding transition states indicate that the CH2=CH group (in the two‐component reaction) and C2H4 (in the three‐component reaction) seem to act as a bridge for electron transfer from the Lewis base center P to the Lewis acid center B. We also investigate the reaction between P(tBu)3, propylene, and B(C6F5)3. The results account well for the experimentally observed regioselectivity. In addition, our calculations also indicate that the presence of fluorine atoms in the borane is essential for stabilizing the addition product.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Study of the hydrophilic‐enhanced ultrafiltration membrane
Authors: Gullinkala Tilak , Escobar Isabel
Published: April 2008

To reduce hydrophobic interactions between natural organic matter (NOM) and the membrane surface, and thereby fouling due to NOM, hydrophilic poly(ethylene glycol) (PEG) monomer chains were attached to a commercially available membrane via in situ graft polymerization. Modification of the membrane was carried out using an oxidizing agent as initiator, PEG monomer, and a chain transfer agent (CTA) as terminating agent. Graft polymerization was carried out by two different methods, bulk (i.e. immersing the membranes in the reactant solutions) and drop (i.e. adding reactants dropwise to the membrane surface). Two different feed solutions were used to characterize the modification. Dextran solution was used to compare the efficiency of each modification method. Synthetic seawater was then used to determine the influence of graft polymerization on flux decline, organic carbon rejection and cake accumulation during filtration. The drop method of modification was found to be the optimal procedure resulting in higher flux and rejection along with improved fouling resistance. Graft polymerization led to an increase in permeability when filtering synthetic seawater containing NOM. FTIR spectra demonstrated the occurrence of modification by showing carbonyl attachment and OH stretching. AFM images indicated lower cake accumulation patterns after modification. © 2008 American Institute of Chemical Engineers Environ Prog, 2008
Testing for Granger (non‐)causality in a time‐varying coefficient VAR model
Authors: Christopoulos Dimitris K. , León‐Ledesma Miguel A.
Published: April 2008

In this paper we propose Granger (non‐)causality tests based on a VAR model allowing for time‐varying coefficients. The functional form of the time‐varying coefficients is a logistic smooth transition autoregressive (LSTAR) model using time as the transition variable. The model allows for testing Granger non‐causality when the VAR is subject to a smooth break in the coefficients of the Granger causal variables. The proposed test then is applied to the money–output relationship using quarterly US data for the period 1952:2–2002:4. We find that causality from money to output becomes stronger after 1978:4 and the model is shown to have a good out‐of‐sample forecasting performance for output relative to a linear VAR model. Copyright © 2008 John Wiley & Sons, Ltd.
Hydrodynamic modelling for water‐saving strategies in irrigation canals
Authors: Khan Muhammad Zubair , Ghumman Abdul Razzaq
Published: April 2008

In this paper a hydrodynamic model was applied for evaluation of water‐saving strategies in systems where there is wastage of water due to oversupply in periods of low demand. The one‐dimensional hydrodynamic model CanalMan was used to assess water saving in a secondary canal. Different operational scenarios were evaluated in comparison with the existing operational strategy. This included the operation of the canal at different discharges combined with night closure, in periods of low demand. Time–discharge hydrographs were prepared using the numerical model for operation of canals having daily opening and closing with full supply, 80 and 70% of design discharge. These hydrographs were used to estimate possible time duration of canal operation for these discharges in the case of night closure. Water saving by night closure was compared with that from operation having weekly rotations.

Study of the existing operational practices indicated extremely high oversupply to the canal compared with crop water requirements, especially in the months of August, November and December. Significant water saving was found by night closure and operating the canal at reduced discharges. Copyright © 2008 John Wiley & Sons, Ltd.
Fabrication and characterization of novel nano‐ and micro‐HA/PCL composite scaffolds using a modified rapid prototyping process
Authors: Heo Su‐Jin , Kim Seung‐Eon , Wei Jie , Hyun Yong‐Taek , Yun Hui‐Suk , Kim Dong‐Hwa , Shin Ji Won , Shin Jung‐Woog
Published: April 2008

Novel three‐dimensional scaffolds consisting of nano‐ and microsized hydroxyapatite (HA)/poly(ϵ‐caprolactone) (PCL) composite were fabricated using a modified rapid‐prototyping (RP) technique for bone tissue engineering applications. The size of the nano‐HA ranged from 20 to 90 nm, whereas that of the micro‐HA ranged from 20 to 80 μm. The scaffold macropores were well interconnected, with a porosity of 72–73% and a pore size of 500 μm. The compressive modulus of the nano‐HA/PCL and micro‐HA/PCL scaffolds was 3.187 ± 0.06 and 1.345 ± 0.05 MPa, respectively. The higher modulus of the nano‐HA/PCL composite (n‐HPC) was to be likely caused by a dispersion strengthening effect. The attachment and proliferation of MG‐63 cells on n‐HPC were better than that on the micro‐HA/PCL composite (m‐HPC) scaffold. The n‐HPC was more hydrophilic than the m‐HPC because of the greater surface area of HA exposed to the scaffold surface. This may give rise to better cell attachment and proliferation. Bioactive n‐HA/PCL composite scaffold prepared using a modified RP technique has a potential application in bone tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Polymer surfaces structured with random or aligned electrospun nanofibers to promote the adhesion of blood platelets
Authors: Wan Ling‐Shu , Xu Zhi‐Kang
Published: April 2008

Fibrous membranes (nonwoven meshes) prepared via electrospinning technique have great potential in tissue engineering. This work is the first study on the behaviors of blood platelets at the nanostructured surface generated by electrospinning. Poly[acrylonitrile‐co‐(N‐vinyl‐2‐pyrrolidone)] (PANCNVP) that shows excellent antiplatelet adhesion ability was directly electrospun onto its dense membrane surface. Polyacrylonitrile (PAN) samples were used as controls. The depth as well as the density of the nanofibers can be easily controlled. The results showed that the PANCNVP dense membrane certainly suppressed the activation and adhesion of platelets. However, whether the nanofibers and underlying membranes were composed of PAN or PANCNVP, the nanostructured surfaces promoted the activation, adhesion, and orientation of platelets. It was also found that, if the space between fibers was too large or the depth of fibers was too small, the nanostructured surface did not change the property of antiplatelet adhesion of PANCNVP. The promotion of activation and adhesion of platelets was obviously due to the presence of nanofibers, which induced the changes of surface topography and charge. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Quantitative in vivo cytokine analysis at synthetic biomaterial implant sites
Authors: Rodriguez Analiz , Meyerson Howard , Anderson James M.
Published: April 2008

To further elucidate the foreign body reaction, investigation of cytokines at biomaterial implant sites was carried out using a multiplex immunoassay and ELISA. Macrophage activation cytokines (IL‐1β, IL‐6, and TNFα), cytokines important for macrophage fusion (IL‐4 and IL‐13), antiinflammatory cytokines (IL‐10 and TGFβ), chemokines (GRO/KC, MCP‐1), and the T‐cell activation cytokine IL‐2 were quantified at biomaterial implant sites. Empty cages (controls) or cages containing synthetic biomedical polymer (Elasthane 80A (PEU), silicone rubber (SR), or polyethylene terephthalate (PET)) were implanted subcutaneously in Sprague‐Dawley rats for 4, 7, or 14 days, and cytokines in exudate supernatants and macrophage surface adhesion and fusion were quantified. The presence of a polymer implant did not affect the levels of IL‐1β, TGFβ, and MCP‐1 in comparison to the control group. IL‐2 was not virtually detected in any of the samples. Although the levels of IL‐4, IL‐13, IL‐10, and GRO/KC were affected by polymer implantation, but not dependent on a specific polymer, IL‐6 and TNFα were significantly greater in those animals implanted with PEU and SR, materials that do not promote fusion. The results indicate that differential material‐dependent cytokine profiles are produced by surface adherent macrophages and foreign body giant cells in vivo. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Bacterial adherence to SiO2‐based multifunctional bioceramics
Authors: Kinnari Teemu J. , Esteban Jaime , Gomez‐Barrena Enrique , Zamora Nieves , Fernandez‐Roblas Ricardo , Nieto Alejandra , Doadrio Juan C. , López‐Noriega Adolfo , Ruiz‐Hernández Eduardo , Arcos Daniel , Vallet‐Regí María
Published: April 2008

The bacterial adherence onto different multifunctional silica‐based bioceramics has been evaluated. Staphylococcus aureus and Staphylococcus epidermidis were chosen, as they cause the majority of the implant‐related infections in this field. Two SiO2 mesoporous materials (MCM‐41, SBA‐15), an ordered SiO2‐CaO‐P2O5 mesoporous glass (OMG), and a biphasic magnetic bioceramic (BMB), were incubated with S. aureus and S. epidermidis for 90 min, and subsequently sonicated to quantify the number of adhered bacteria on each material. It was found that S. aureus and S. epidermidis (108 CFU/mL) adhered significantly less to BMB samples when compared to MCM‐41, SBA‐15, or OMG. However, when the material pores accessible for bacteria in each material were taken into account, the lowest bacterial adherence was found in MCM‐41, and the highest in SBA‐15. The results show that bacterial adherence is higher on mesoporous bioceramics, although this higher microbial attachment is mainly due to the intergranular porosity and grain size morphology rather than to the mesoporous structure. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Effect of dynamic 3‐D culture on proliferation, distribution, and osteogenic differentiation of human mesenchymal stem cells
Authors: Stiehler Maik , Bünger Cody , Baatrup Anette , Lind Martin , Kassem Moustapha , Mygind Tina
Published: April 2008

Ex vivo engineering of autologous bone tissue as an alternative to bone grafting is a major clinical need. In the present study, we evaluated the effect of 3‐D dynamic spinner flask culture on the proliferation, distribution, and differentiation of human mesenchymal stem cells (MSCs). Immortalized human MSCs were cultured on porous 75:25 PLGA scaffolds for up to 3 weeks. Dynamically cultured cell/scaffold constructs demonstrated a 20% increase in DNA content (21 days), enhanced ALP specific activity (7 days and 21 days), a more than tenfold higher Ca2+ content (21 days), and significantly increased transcript levels of early osteogenesis markers (e.g., COL1A1, BMP2, RUNX‐2) as compared with static culture. Despite the formation of a dense superficial cell layer, markedly increased cell ingrowth was observed by fluorescence microscopy on day 21. Furthermore, increased extracellular matrix deposition was visualized by scanning electron microscopy after 1 and 3 weeks of dynamic culture. The observed increased ingrowth and osteogenic differentiation of 3‐D dynamically cultured human MSCs can be explained by generation of fluid shear stress and enhanced mass transport to the interior of the scaffold mimicking the native microenvironment of bone cells. This study provides evidence for the effectiveness of dynamic culture of human MSCs during the initial phase of ex vivo osteogenesis. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Interactions of coronary artery smooth muscle cells with 3D porous polyurethane scaffolds
Authors: Grenier Stéphanie , Sandig Martin , Holdsworth David W. , Mequanint Kibret
Published: April 2008

One strategy in vascular tissue engineering is the design of hybrid vascular substitutes where vascular cells infiltrate biostable porous scaffolds that provides favorable environment for guided cell repopulation and acts as a mechanically supporting layer after the tissue regeneration process. The aim of the present work was to study the interaction of human coronary artery smooth muscle cells (HCASMC) with 3D porous polyurethane scaffolds. We therefore fabricated porous and highly interconnected 3D polyurethane scaffolds that can promote HCASMC attachment, proliferation, and migration. SEM and microCT studies of the fabricated scaffolds showed that the current scaffolds had highly open and interconnected pore structures, with an average porosity of 84%. HCASMC interaction on polyurethane films revealed that cells adhere and express specific marker proteins (vinculin and h‐caldesmon). This expression was further enhanced by coating the polyurethane with Matrigel. On uncoated 3D scaffolds, dense spherical aggregates of cells were often encountered with little adhesion of individual cells alongside the struts of the scaffold, independent of the porogens used. In contrast, when cultured on Matrigel‐coated scaffolds, cell numbers quickly increased after 14 days and spread along the entire scaffold. At the upper scaffold surface, elongated cells were seen adhering to one another and also to the scaffold surface. These cells were elongated, aligned in parallel and contained abundant F‐actin bundles suggesting a differentiated contractile phenotype. Deep into the scaffold, cells were encountered that formed actin‐rich lamellipodial extensions spreading along the strut and lacked stress fibers, suggesting active cell migration along the substrate. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Resorbable polymeric scaffolds for bone tissue engineering: The influence of their microstructure on the growth of human osteoblast‐like MG 63 cells
Authors: Pamula Elzbieta , Filová Elena , Bačáková Lucie , Lisá Věra , Adamczyk Daniel
Published: April 2008

Degradable three‐dimensional porous scaffolds applicable as cell carriers for bone tissue engineering were developed by an innovative solvent casting/particulate leaching technique from poly(L‐lactide‐co‐glycolide) (PLG). Three types of PLG scaffolds were prepared, and these had the same high porosity (83%) but increasing diameter of the pores (180–200 μm, 250–320 μm, and 400–600 μm) and increasing pore interconnectivity. The colonization of the scaffolds with human osteoblast‐like MG 63 cells was then studied in vitro in a conventional static cell culture system. The number of cells growing on the scaffolds on days 1 and 7 after seeding was highest in the material with the largest pore diameter, but on day 15, the differences among the scaffolds disappeared. Confocal microscopy revealed that on day 1 after seeding, the cells penetrated to a depth of 490 ± 100 μm, 720 ± 170 μm, and 720 ± 120 μm into the scaffolds of small, medium, and large pore size, respectively. Incorporation of bromodeoxyuridine into newly synthesized DNA and the concentration of vinculin, β‐actin, osteopontin, and osteocalcin in cells on the scaffolds of all pore sizes were similar to the values obtained on standard tissue culture polystyrene, which indicated good biocompatibility of the scaffolds. These results suggest that all scaffolds could serve as good carriers for bone cells, although the quickest colonization with cells was found in the scaffolds with the largest pore diameter from 400 to 600 μm. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
In vitro and in vivo evaluation of acellular diaphragmatic matrices seeded with muscle precursors cells and coated with VEGF silica gels to repair muscle defect of the diaphragm
Authors: Conconi Maria T. , Bellini Silvia , Teoli Debora , de Coppi Paolo , Ribatti Domenico , Nico Beatrice , Simonato Enea , Gamba Pier G. , Nussdorfer Gastone G. , Morpurgo Margherita , Parnigotto Pier P.
Published: April 2008

In this work, a bioartificial system consisting of VEGF‐loaded porous silica gel and myoblasts cultured on acellular diaphragmatic matrix (ADM) has been implanted to repair a surgically created diaphragmatic defect in Lewis rats. ADMs exerted a strong angiogenic response on chorio‐allantoic membrane. Cytotoxicity, VEGF release and matrix erodibility in vitro tests demonstrated that the silica support was nontoxic and that the VEGF bioactivity was maintained after matrix entrapment and it was released within a timeframe that can be modulated by synthesis parameters. Different grafts composed by ADMs with and without autologous male myoblasts or/and VEGF‐loaded porous silica gel have been implanted to repair previously created diaphragmatic defects in female Lewis rats. Patches composed of ADMs and myoblasts appeared well preserved until 8 weeks, and contained multinucleated cells and cholinergic fibers. At 8 weeks, the implanted cells were still present inside the patches. The disappointing results obtained when VEGF was delivered by porous silica gel were probably due to an abnormal angiogenic response following an excess of local growth factor concentration. Taken together, these results confirmed that our matrices contained biologically active angiogenic factors which were per se sufficient to induce neo‐vessels formation, thus allowing the survival of implanted myoblasts. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
EP4 agonist accelerates osteoinduction and degradation of β‐tricalcium phosphate by stimulating osteoclastogenesis
Authors: Nasu Tomonori , Takemoto Mitsuru , Akiyama Norihiro , Fujibayashi Shunsuke , Neo Masashi , Nakamura Takashi
Published: April 2008

Porous β‐tricalcium phosphate (TCP) has been known to have osteoinductive potential in ectopic site implantation in canine models without the use of osteoinductive substances or cell transplantation. Prostaglandin E2 receptors, particularly EP4, are known to play an important role in osteogenesis. EP4 agonists have been demonstrated to have positive effects on bone remodeling and bone morphogenic protein‐induced ectopic bone formation in rodent models. We examined the efficiency of porousβ‐TCP‐induced osteoinduction in beagles by the graded‐release EP4 agonist, which was injected at their buttocks intramuscularly. Newly formed bone was observed on and after 3 weeks in the EP4 agonist‐injected, while on and after 6 weeks in control groups, respectively. After that the bone resorption and the β‐TCP degradation was accelerated in EP4 agonist‐injected group. Tartarate‐resistant acid phosphatase‐positive cells appeared in each group before bone formation, and the number of these cells reduced gradually; however, more multinucleated and larger cells appeared, particularly in the injected group. Injection of an EP4 agonist was proved to accelerate the osteoinduction and degradation of β‐TCP in canine model. Histological analysis revealed that the EP4 agonist stimulated osteoclastogenesis before bone formation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
PEOT/PBT based scaffolds with low mechanical properties improve cartilage repair tissue formation in osteochondral defects
Authors: Jansen Edwin J. P. , Pieper Jeroen , Gijbels Marion J. J. , Guldemond Nick A. , Riesle Jens , Van Rhijn Lodewijk W. , Bulstra Sjoerd K. , Kuijer Roel
Published: April 2008

The aim of our study was to compare the healing response of biomechanically and biochemically different scaffolds in osteochondral defects created in rabbit medial femoral condyles. A block copolymer comprised of poly(ethylene oxide terephthalate) and poly(butylene terephthalate) was used to prepare porous scaffolds. The 70/30 scaffold (70 wt % poly(ethylene oxide terephthalate)) was compared to the stiffer 55/45 (55 wt % poly(ethylene oxide terephthalate)) scaffold. Nine 6‐month‐old rabbits were used. Osteochondral defects were filled with 55/45 scaffolds (n = 6); 70/30 scaffolds (n = 6); or left empty (n = 6). Defect sites were allowed to heal for 12 weeks. Condyles were macroscopically evaluated and analysed histologically using the O'Driscoll score for evaluating repair of osteochondral defects. Repair tissue in 70/30 scaffolds consisted of cartilage‐like tissue on top of trabecular bone, whereas the tissue within the 55/45 scaffolds consisted predominantly of trabecular bone. O'Driscoll scores for 70/30 scaffolds were significantly better (p = 0.024) in comparison to untreated osteochondral defects and 55/45 scaffolds. This study reveals that the biomechanical and biochemical properties of the scaffold play an important role by themselves, and can affect the healing response of osteochondral defects. Scaffolds with low mechanical properties were superior in cartilage repair tissue formation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Study of hydroxyapatite osteoinductivity with an osteogenic differentiation of mesenchymal stem cells
Authors: Lin Liwen , Chow King L. , Leng Yang
Published: April 2008

Osteoinductivity of hydroxyapatite (HA) was investigated using uncommitted pluripotent mouse stem cells, C3H10T1/2 in an in vitro differentiation assay. For comparative analysis, the cells were cultured on substrates made of osteoinductive HA, with biocompatible titanium and plastics as the negative control. HA exhibited the ability to induce expression of osteo‐specific genes in C3H10T1/2, including alkaline phosphatase (ALP), type I collagen, and osteocalcin; compared with its insignificant up‐regulation of the same genes in osteoblast‐like cells, Saos‐2. HA osteoinductivity exhibited in C3H10T1/2 was comparable to that of a bone morphogenetic protein (BMP) with reference to the up‐regulation of osteo‐specific genes except the core binding factor 1 (Cbfa1, Runx). This result implies a difference in osteogenic induction pathway initiated by HA and BMP. Using this mesenchymal stem cells (MSC) culture assay, osteoinductivity was also demonstrated to be present in the conditioned medium derived from MSC cultured on HA substrates. This conditioned medium exhibited excellent ability to up‐regulate ALP in the absence of HA and BMP. The results suggest that the HA can interact with the cells and generate potent inductive substance released into the medium. Such substance in turn is able to induce uncommitted cells to differentiate into the osteolineage. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Comparative in vivo evaluation of porous and dense duplex titanium and hydroxyapatite coating with high roughnesses in different implantation environments
Authors: Borsari V. , Fini M. , Giavaresi G. , Tschon M. , Chiesa R. , Chiusoli L. , Salito A. , Rimondini L. , Giardino R.
Published: April 2008

Ti (PG60) and Ti plus HA (HPG60) dense coatings with ultrahigh roughness (Ra: 74 ± 8 μm and 53 ± 18 μm, respectively) were compared to high Ti (Ti60) and Ti plus HA (HT60) high roughened porous coatings (Ra: 40 ± 7 μm and 36 ± 3 μm, respectively). Surfaces were implanted in cortical and trabecular bone of young adult (YOUNG), aged (AGED) and estrogen‐deficient sheep (OVX) and analyzed by means of histology, histomorphometry and push‐out tests 3 months after implantation. A significantly lower value in affinity index (AI) of PG60 when compared to TI60 (p < 0.01) was observed in cortical bone. In trabecular bone, lower values in AI were found in TI60 and PG60 when compared to their HA‐coated surfaces (p < 0.0005). Bone ingrowth (BI) of TI60 and PG60 was significantly lower than that of the HA‐coated surfaces in trabecular bone (p < 0.05). Significantly lower values in BI in OVX sheep in comparison to YOUNG sheep in both cortical and trabecular bone were observed (p < 0.05). Data showed that high roughness and Ti and HA‐coated surfaces are suitable for aged and osteoporotic patients. HA coatings represent the most successful strategy in trabecular bone. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009