bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Phase Diagram Information and Computational Thermodynamics
Authors: Kattner U. R.
Published: August 2006

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, please click on HTML or PDF.
Metastable Solidification of Composites
Authors: Eggeler Gunther , Granasy Laszlo , Herlach Dieter M. , Kolbe Matthias , Ludwig Andreas , Rappaz Michel , Duursma Rene , Jestrabek Juergen , Charbon Christian , Sellger Roland , et al. et al.
Published: August 2006

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, please click on HTML or PDF.
Electrochemical Promotion of Catalysis at Metal Surfaces
Authors: Metcalfe I. S.
Published: August 2006

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, please click on HTML or PDF.
Propylene Oxide Synthesis and Selective Oxidation over Supported Metal Oxide Photocatalysts with Molecular Oxygen
Authors: Amano Fumiaki , Tanaka Tsunehiro
Published: August 2006

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, please click on HTML or PDF.
Recent Advances in Ring Transformation of Five‐Membered Heterocycles
Authors: Hejtmankova Ludmila , Sedlak Milos
Published: August 2006

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, please click on HTML or PDF.
Highly Functionalized Heterocycles and Macrocycles from Pentafluoropyridine
Authors: Sandford Graham
Published: August 2006

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, please click on HTML or PDF.
Fluoroform, Fluoral, Trifluoroacetic, and Trifluoromethanesulfinic Acid Derivatives as New Reagents for the Introduction of Polyfluorinated Moieties
Authors: Langlois Bernard R. , Billard Thierry
Published: August 2006

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, please click on HTML or PDF.
Low‐Valent Titanium‐Mediated Reductive Coupling of Carbonyl Compounds
Authors: Ladipo Folami T.
Published: August 2006

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, please click on HTML or PDF.
Engineering Stereospecific Reactions in Crystals: Synthesis of Compounds with Adjacent Stereogenic Quaternary Centers by Photodecarbonylation of Crystalline Ketones
Authors: Mortko Christopher J. , Garcia‐Garibay Miguel A.
Published: August 2006

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, please click on HTML or PDF.
Investigating Transport Proteins by Solid State NMR
Authors: Basting Daniel , Lehner Ines , Lorch Mark , Glaubitz Clemens
Published: August 2006

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, please click on HTML or PDF.
Peptidomics: Identification and Quantification of Endogenous Peptides in Neuroendocrine Tissues
Authors: Fricker Lloyd D. , Lim Jihyeon , Pan Hui , Che Fa‐Yun
Published: August 2006

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, please click on HTML or PDF.
Fourier transform near‐infrared vibrational circular dichroism used for on‐line monitoring the epimerization of 2,2‐dimethyl‐1,3‐dioxolane‐4‐methanol: A pseudo racemization reaction
Authors: Guo Changning , Shah Rekha D. , Mills John , Dukor Rina K. , Cao Xiaolin , Freedman Teresa B. , Nafie Laurence A.
Published: August 2006

Near‐infrared (near‐IR) Fourier transform vibrational circular dichroism (FT‐VCD) spectroscopy has been used to monitor the epimerization of (S)‐(+)‐2,2‐dimethyl‐1,3‐dioxolane‐4‐methanol (S‐DDM). The near‐IR‐VCD spectra display clear isolated VCD bands at the range of 4700–5050 cm−1 resulting from the OH stretch‐bend combination bands of S‐DDM, which were found to decrease in intensity with increasing reaction time. The near‐IR‐VCD spectra of 10 reference samples obtained were subjected to partial least‐squares (PLS) regression analysis, and the results were used to build predictive models for enantiomeric excess (EE) determination. Multivariate regression was carried out on three different sets of spectra, corresponding to the epimerization of S‐DDM in three different solvents: methylcyclohexane, carbon tetrachloride and tetrahydrofuran. The effects of solvent in DDM epimerization are discussed in terms of the relative stabilization of the reaction intermediate of the DDM epimerization reaction. The results of these near‐IR‐VCD studies for the determination of EE highlights the potential of VCD for in situ real‐time process monitoring of the reaction kinetics of chiral molecules in solution. Chirality, 2006. © 2006 Wiley‐Liss, Inc.
Chirality of camphor derivatives by density functional theory
Authors: Morita Hayato E. , Kodama Takashi S. , Tanaka Takeyuki
Published: August 2006

Infrared (IR) and vibrational circular dichroism (VCD) spectra of chiral camphor, camphorquinone and camphor‐10‐sulfonic acid (CSA), known as standard compounds for electronic circular dichroism (ECD) spectroscopy, are measured and their vibrational frequencies, infrared intensities, and rotational strengths are calculated using density functional theory (DFT). The observed IR and VCD spectra of chiral camphor and camphorquinone in carbon tetrachloride solution are reproduced by the DFT calculations, but those of CSA are not. DFT calculations of hydration models, where an anionic CSA specifically binds a few water molecules, are carried out. The average of the simulated VCD spectra in the hydration models is more consistent with the observed spectra. In addition, the wavelengths and dipole and rotational strengths for chiral camphor, camphorquinone, anionic CSA, and the hydration models were calculated by time‐dependent DFT. In the region of 280–300 nm, the calculated wavelengths of the ECD bands for chiral camphor and camphorquinone coincide with the observed wavelengths that have been reported, and the calculated wavelengths for the hydration models are closer to the observed wavelengths reported than are those calculated for chiral anionic CSA. Consequently, the analysis combined with VCD and ECD spectroscopy using DFT calculations can elucidate the chirality of optically active molecules, even in an aqueous solution. Chirality, 2006. © 2006 Wiley‐Liss, Inc.
Databases for spectral color science
Authors: Kohonen Oili , Parkkinen Jussi , Jääskeläinen Timo
Published: August 2006

In color science, spectral representation and analysis of colors have become a common approach to study color‐related problems, e.g., accurate industrial color measurement or analysis of color images. In developing algorithms for spectral color science, one often relies on existing databases of reflectance color spectra. Since a number of these databases are easily available, the same databases are commonly used by different research groups. During year 2003 the most popular one of our publicly available spectral reflectance databases was visited over 600 times. In the present article, we describe these color spectra databases and analyze their utility for spectral color science. However, the article does not take the complexity of fluorescent surfaces into account. The aim of this article is to set a solid ground for the comparisons of different methods in the spectral color science. The databases presented here include measured color spectra of natural and man‐made objects as well as spectra of some sets of standard colors. In addition to the commonly used data sets, some new data sets, including a set of standard calibrated colors and a set of natural colors, measured with 10 nm spectral resolution are introduced. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 381–390, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20244
Concerning the calculation of the color gamut in a digital camera
Authors: Martínez‐Verdú Francisco , Luque María José , Capilla Pascual , Pujol Jaume
Published: August 2006

Several methods to determine the color gamut of any digital camera are shown. Since an input device is additive, its color triangle was obtained from their spectral sensitivities, and it was compared with the theoretical sensors of Ives‐Abney‐Yule and MacAdam. On the other hand, the RGB digital data of the optimal or MacAdam colors were simulated to transform them into XYZ data according to the colorimetric profile of the digital camera. From this, the MacAdam limits associated to the digital camera are compared with the corresponding ones of the CIE‐1931 XYZ standard observer, resulting that our color device has much smaller MacAdam loci than those of the colorimetric standard observer. Taking this into account, we have estimated the reduction of discernible colors by the digital camera applying a chromatic discrimination model and a packing algorithm to obtain color discrimination ellipses. Calculating the relative decrement of distinguishable colors by the digital camera in comparison with the colorimetric standard observer at different luminance factors of the optimal colors, we have found that the camera distinguishes considerably fewer very dark than very light ones, but relatively much more colors with middle lightness (Y between 40 and 70, or L* between 69.5 and 87.0). This behavior is due to the short dynamic range of the digital camera response. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 399–410, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20245
Theoretical analysis of subtractive color mixture characteristics V—Centroid of subtractive tristimulus values
Authors: Matsushiro Nobuhito , Ohta Noboru
Published: August 2006

In additive color mixture, when more than two component tristimulus values are given then the mixture result is determined from a linear combination of the components. On the other hand, in subtractive color mixture, the resultant tristimulus values are not uniquely determined from component tristimulus values. Hence, analyses regarding the minimum and the maximum bounds are very important to understand the possible ranges of tristimulus values of subtractive color mixture. In our previous series of articles, several theorems have been proven related to the bounds. In addition to the values, the centroid of a possible range is very important and essential to the prediction of subtractive color mixture. In the present article, several theorems related to the centroid are provided and proven. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 418–424, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20247
Intrusions, avoidance and overgeneral memory in a non‐clinical sample
Authors: Hauer Beatrijs J. A. , Wessel I. , Merckelbach H.
Published: August 2006

Previous studies have shown a positive relationship between intrusions, effortful avoidance and overgeneral memory in people suffering from (mild) depression or PTSD. The purpose of the present study was to investigate these relationships in a non‐clinical sample. As part of a mass testing session, a written version of the Autobiographical Memory Test was administered to 175 first‐year psychology students. Furthermore, intrusion and avoidance symptoms were measured with the Impact of Event Scale (Horowitz, Wilner, & Alvarez, 1979), and depressive symptoms with the Beck Depression Inventory (Beck, Ward, Mendelson, Mock, & Erbaugh, 1961). The data demonstrated a significant correlation between avoidance symptoms and categoric memory to negative cue words. This relationship remained significant after controlling for depressive symptoms. These results concur with other findings that overgeneral memory tends to be related to symptoms of effortful avoidance. Copyright © 2006 John Wiley & Sons, Ltd.
The probability of treatment success, failure and duration—what can be learned from empirical data to support decision making in clinical practice?
Authors: Lutz Wolfgang , Lambert Michael J. , Harmon S. Cory , Tschitsaz Armita , Schürch Eva , Stulz Niklaus
Published: August 2006

Empirical methods have been found to be superior to clinical judgment for the purpose of correctly identifying patients at risk for treatment failure and, hence, to enhance psychotherapy outcomes. The development and evaluation of an empirical approach aimed at supporting clinical decisions during the course of psychotherapy is described. The tool provides predictions based on a patient‐specific sampling strategy called the nearest neighbors method and on growth curve approaches to model an expected treatment course for each patient. Using session‐by‐session data from an outpatient center in the US (N = 4365), this new empirically derived decision model was evaluated and compared with a clinically based approach loosely based on an adaptation of clinically significant change concepts. The empirically derived decision system was found to be superior to the rational clinically based one in almost all measures of prediction accuracy, indicating its potential to identify patients at risk for treatment failure. Copyright © 2006 John Wiley & Sons, Ltd.
Cystic fibrosis transmembrane conductance regulator (CFTR) dependent cytoskeletal tension during lung organogenesis
Authors: Cohen J. Craig , Larson Janet E.
Published: August 2006

There is growing evidence for the role of CFTR (cystic fibrosis transmembrane conductance regulator) in lung development and differentiation. The mechanism by which the chloride channel could affect lung organogenesis, however, is unknown. In utero CFTR gene transfer in the fetal lungs of mice, rats, and non‐human primates was shown previously to alter lung structure and function. A study of the genes altered in the fetal rat lung following CFTR overexpression was initiated in an effort to determine the molecular mechanism for CFTR‐dependent differentiation. In utero gene transfer with recombinant adenoviruses carrying either a reporter gene or CFTR resulted in the increased expression of a number of genes upon microarray analysis. The majority of the genes overexpressed in the CFTR‐treated lungs were primarily associated with muscle structure and function. Histological and biochemical characterization of these proteins including myosin heavy chain, heat shock protein 27, and isoforms of myosin light chain showed that CFTR overexpression had a profound effect on smooth muscle contraction‐related proteins. The CFTR‐dependent regulation of smooth muscle contraction related proteins was shown to be related to chloride and extracellular ATP and was dependent upon the PI3 Kinase and Phospholipase C pathways. The changes in smooth muscle proteins were consistent with CFTR‐dependent contractions of the embryonic airway smooth muscle. An assay was developed using fluorescent polystyrene beads to show that CFTR did indeed increase amniotic fluid flow into the fetal lung. Increased amniotic fluid pressure was shown previously to be associated with stretch‐induced differentiation of the lung. Evaluation of neonatal respiratory function showed that CFTR‐dependent muscle contractions and increased amniotic fluid pressure resulted in accelerated maturation of the neonatal rat lung. In addition, these CFTR‐dependent changes were shown to be sufficient to reverse the lung phenotype of the CFTR knockout mouse. Mechanical forces influence lung development through pulmonary distension. CFTR overexpression in the fetal lung altered differentiation and development in the lung. These results are consistent with CFTR influencing lung development by regulating the muscle contractions associated with cytoskeletal tension and stretch induced differentiation. Deficiency of CFTR altering lung development would contribute significantly to the Cystic Fibrosis disease phenotype. Developmental Dynamics 235:2736–2748, 2006. © 2006 Wiley‐Liss, Inc.
Evidence of NK cell dysfunction in SIV‐infected rhesus monkeys: Impairment of cytokine secretion and NKG2C/C2 expression
Authors: LaBonte Michelle L. , McKay Paul F. , Letvin Norman L.
Published: August 2006

Defects in the adaptive immune response have been extensively characterized in human immunodeficiency virus type‐1 (HIV‐1)‐infected individuals; however, much less is known about the function of natural killer (NK) cells during the course of HIV‐1 infection. In the present study, we demonstrate that the NK cells from simian immunodeficiency virus (SIV)‐infected rhesus monkeys are significantly impaired in their ability to secrete IFN‐γ, TNF‐α, and IL‐2, while NK cell function in SIV‐infected long‐term non‐progressor monkeys is similar to that of normal monkeys. These findings suggest that abnormal NK cell activity may contribute to the global immune dysfunction observed in HIV‐1‐infected individuals. NK cell function is modulated by several families of cell surface receptors, including the CD94/NKG2 family. We evaluated the messenger RNA levels of these inhibitory and activating NKG2 molecules in SIV‐infected rhesus monkeys. These experiments demonstrate that the activating molecules NKG2C and NKG2C2 are significantly down‐regulated in peripheral blood mononuclear cells of SIV‐infected rhesus monkeys, suggesting that the dysregulation of these molecules may contribute to the abnormal NK cell function observed in the setting of infection.
How Do the Different Defect Structures and Element Substitutions Affect the Nonlinear Optical Properties of Lacunary Keggin Polyoxometalates? A DFT Study
Authors: Guan Wei , Yang Guo‐Chun , Yan Li‐Kai , Su Zhong‐Min
Published: August 2006

Systematic DFT calculations have been carried out on the lacunary α‐Keggin polyoxometalate derivatives [PW11O39]7–, [XW9O34]n– (X = AlIII, SiIV, GeIV, PV, AsV, and SbV), [XW9M2O39]n–, and [XW9M3O40]n– (X = PV and SiIV, M = MoVI, VV, NbV, and TaV) to investigate the geometric structure and element substitution effects on the molecular nonlinear optical response. Analysis of the computed static second‐order polarizability (β0) predicts that the molecular nonlinear optical activity of lacunary Keggin polyoxometalate derivatives can be modified by replacing the central heteroatom and the addenda metal atom. Substitution of the central Al atom or the addenda V atom causes significant enhancement in the molecular nonlinearity. Moreover, the β0 values are substantially dependent on the defect structures. This class of inorganic complexes possesses remarkably large molecular optical nonlinearity, especially for the partial substitution complex [SiW9Nb2O39]10– (IIIc), which has a computed β0 value of 2071.0 a.u. Thus, lacunary Keggin polyoxometalates could become excellent candidates in the field of second‐order NLO. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Examination of cellular and molecular events associated with optic nerve axotomy
Authors: Nitzan Anat , Kermer Pawel , Shirvan Anat , Bähr Mathias , Barzilai Ari , Solomon Arieh S.
Published: August 2006

Purpose: Analyzing cellular behavior during scar formation and determining the expression of growth inhibiting molecules in the optic nerve and retina following acute optic nerve injury. Methods: A rat model of complete transection of the optic nerve that spares the vascular supply and the neural scaffold was used. The response of the optic nerve and retinas to axotomy was studied by immunological and biochemical approaches. Results: Optic nerve axotomy led to massive cell invasion at the site of injury that spread along both sides of the nerve. The cells were microglia, oligodendrocytes, and to a lesser extent astrocytes. A marked induction of semaphorin 3A was evident, especially in the area of the scar, and persisted up to the 28th day of the experiment. Expression of neuropilin‐1, a component of the semaphorin 3A receptor, increased following injury. The molecular events associated with axotomy were studied by measuring the levels of semaphorin 3A, p38 MAPK, and ERK1/2 in the retina. Semaphorin 3A levels and the activated form of p38 were elevated 3 days post‐axotomy and then declined; ERK1/2 activation levels reached their peak 14 days post axotomy. Acute nerve injury led to morphological alterations in oligodendrocytes, astrocytes, and the extracellular matrix, disrupting the delicate internal organization of the optic nerve. Conclusions: We suggest that cell invasion, semaphorin 3A and neuropilin‐1 induction, and disruption of the internal organization of the optic nerve contribute to axotomy‐induced degenerative processes. © 2006 Wiley‐Liss, Inc.
Glial cell line‐derived neurotrophic factor promotes olfactory ensheathing cells migration
Authors: Cao Li , Su Zhida , Zhou Qiang , Lv Baolai , Liu Xiujie , Jiao Li , Li Zhihua , Zhu Yanling , Huang Zhihui , Huang Aijun , He Cheng
Published: August 2006

Olfactory ensheathing cells (OECs) are a unique type of macroglia with axonal growth‐promoting properties. The migrating ability of OECs in CNS is essential for neural regeneration. However, little is known about the extracellular and intracellular factors that regulate OEC migration. In the present study, we examined the effects of glial cell line‐derived neurotrophic factor (GDNF) on OECs migration. Initially, the “scratch” migration assay, Boyden chamber assay, and explant migration assay showed that GDNF could promote OECs migration in vitro. Treatment of OECs with GDNF also induced cytoskeleton reorganization and up‐regulated expression of cytoskeleton proteins. GDNF‐induced OECs migration was demonstrated depending on GFRα‐1 and Ret receptor, and activation of JNK and Src signaling cascades. Furthermore, GDNF was found to promote implanted OECs migration in a spinal cord hemisection injury model. Together, we report, to our knowledge for the first time, that GDNF stimulate OECs migration in vitro and in vivo. © 2006 Wiley‐Liss, Inc.
Experimental results of the tracheoesophageal tissue connector for improved fixation of shunt valves in laryngectomized patients
Authors: Ten Hallers E. J. O. , Marres Henri A. M. , van der Houwen Eduard B. , Jansen John A. , Rakhorst Gerhard , Schutte Harm K. , van Kooten Theo G. , van Loon Jan‐Paul , Verkerke Gijsbertus J.
Published: August 2006

Background.

After total laryngectomy and voice rehabilitation using a tracheoesophageal shunt valve, patients often have valve‐related complications such as leakage. To solve these problems, a tracheoesophageal tissue connector (TE‐TC) was devised to serve as an interface between the patient's tissue (trachea and esophagus) and the shunt valve.

Methods.

The TE‐TC is a permucosal connection constructed from a titanium ring (filled with a silicon rubber plug) combined with polypropylene or titanium mesh. After implantation in adult goats for 12 weeks the implants were submitted to histologic investigation.

Results.

Firm implant fixation was achieved. In nearly all (18/19), no signs of infection of the implant were seen; 11 of 19 animals died before the end of the experiment owing to complications not related to the implant.

Conclusions.

The TE‐TC is a new device with potential in the solution for fixation‐related problems in tracheoesophageal voice rehabilitation. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
New approach to large‐volume injection in reversed‐phase high performance liquid chromatography: Determination of atrazine and hydroxyatrazine in soil samples
Authors: Hutta Milan , Chalányová Mária , Halko Radoslav , Góra Róbert , Rybár Ivan , Pajchl Marek , Dokupilová Svetlana
Published: August 2006

A well established method of direct injection of larger than conventional sample volumes ranging from 0.1 mL to 10 mL in HPLC is the injection valve method in which a loop of tubing is totally or partially filled with sample. Recent HPLC pumps have a flow‐rate setting accuracy of ±1–2% over a flow‐rate range from 0.1 mL/min to 10 mL/min and the flow stability is 0.2% or less. Quarternary low pressure gradient pumps are widely available and used, but all their hydraulic lines are seldom utilised. The idea of using one line of a common commercial HPLC quaternary low‐pressure pump for direct on‐column injection (pumping) of large sample volumes ranging from 1 mL to 100 mL was tested. This approach was evaluated during practical work on the development of an RP‐HPLC method of determination of residual atrazine and hydroxyatrazine. In lysimetric environmental experiments hydroxyatrazine was formed in situ in a soil column by hydrolysis of atrazine. The results proved the applicability of this approach not only in experiments with model mixtures of analytes at μg/L levels in solutions. Analysis of 20 mL of soil leachates and extracts of soil samples containing atrazine and hydroxyatrazine at the 10 μg/kg level (in dry soil) revealed that good figures‐of‐merit were preserved, even in the presence of a large excess of humic substances.
Method for enantiomeric purity of a quinuclidine candidate drug by capillary electrophoresis
Authors: Ramstad Tore , Johnson Rebecca L.
Published: August 2006

A chiral procedure based on EKC was developed and validated for determination of the enantiomeric purity of PHA‐543613, a drug candidate that was under development for treatment of the cognitive deficits of Alzheimer's disease and schizophrenia. Separation of enantiomers is accomplished via differential, enantiospecific complexation with a single‐isomer, precisely sulfated beta‐CD and heptakis‐6‐sulfato‐β‐CD (HpS‐β‐CD). Both neutral and sulfated CDs were screened before selecting HpS‐β‐CD as the chiral selector. The separation is conducted in a 61 cm×50 μm uncoated fused silica capillary with 25 mM HpS‐β‐CD in pH 2.50, 25 mM lithium phosphate as the separation buffer with detection at 220 nm. Application of reverse polarity at –30 kV results in an elution time of about 12 min for PHA‐543613 and 13 min for the undesired S‐enantiomer. Quantification is versus an authentic reference S‐enantiomer as an external standard in combination with an internal standard. The procedure was validated over the range 0.1–2.0% w/w. The detection limit is 0.01–0.02%. The amount of distomer intrinsic to the drug substance is about 0.1% or less. The developed method was used to generate stability data on multiple lots: in one case for up to 3 years.
Separation and determination of epinephrine and dopamine in traditional Chinese medicines by micellar electrokinetic capillary chromatography with laser induced fluorescence detection
Authors: Dong Yuming , Chen Hongli , Chen Yonglei , Hui Yang , Chen Xingguo , Hu Zhide
Published: August 2006

A micellar electrokinetic capillary chromatography method with laser‐induced fluorescence detection was developed for the analysis of epinephrine and dopamine after derivatization with 4‐chloro‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole. The optimum derivatization conditions were: 30 mM sodium borate (pH adjusted to 8.0 with 1.0 M HCl), reaction time 30 min at 60°C. Baseline separation was achieved within 14 min with a running buffer composed of 10 mM sodium borate + 25 mM sodium dodecyl sulfate (pH adjusted to 9.5 with 0.1 M NaOH) and an applied voltage of 15 kV. Good linearity relationships (correlation coefficients: 0.9991 for epinephrine and 0.9985 for dopamine) between peak areas and concentrations of the analytes were obtained. The detection limits and quantification limits for epinephrine and dopamine were 0.0038 mg/L and 0.013 mg/L, and 0.065 mg/L and 0.020 mg/L, respectively. The method was applied to the analysis of the two compounds in two Chinese medicines with recoveries in the range of 92.6–108.7%.
Capillary electrochromatography with monolithic silica columns. V. Study of the electrochromatographic behaviors of polar compounds on monolithic silica having surface bound cyano functionalities
Authors: Zhong Hengwen , El Rassi Ziad
Published: August 2006

In this report, a novel polar monolithic capillary column is described for normal phase CEC (NP‐CEC) of representative polar compounds including mono‐ and oligosaccharides, peptides, and basic drugs. The polar monolithic column, which was described in detail in the preceding paper, consisted of silica‐based monolith bonded with 1H‐imidazole‐4,5‐dicarbonitrile (IDCN) and is denoted as 2CN‐OH‐Monolith. Various retention parameters for neutral polar solutes (e. g., mono‐ and oligosaccharides) and charged polar solutes (e. g., peptides and basic drugs) were evaluated over a wide‐range of elution conditions. These retention parameters yielded quantitative assessment for the polar interactions between the model solutes and the stationary phase under investigation as well as the effect of electromigration of charged solutes on their overall migration in NP‐CEC. Furthermore, this investigation demonstrated that despite the possibility of achieving isocratic separation in NP‐CEC for widely differing polar species, multistep‐gradient elution in NP‐CEC is preferred to bring about the rapid separation of a large number of polar species in a single run.
Preparation of particle‐fixed silica monoliths used in capillary electrochromatography
Authors: Qu Qishu , Tang Xiaoqing , Wang Chengyin , Yang Gongjun , Hu Xiaoya , Lu Xiao , Liu Yin , Yan Chao
Published: August 2006

Fused‐silica capillaries were packed with porous 1 μm bare silica microspheres and immobilized by potassium silicate–formamide in order to obtain columns with silica‐based monolithic packing. After curing, the particle‐fixed monolithic columns were octadecylated in situ with dimethyloctadecylchlorosilane. The columns were mechanically strong and permeable. No noticeable loss in efficiency was found after using a column continuously for 1 month. The performances of the particle‐fixed silica monolithic columns were evaluated for CEC under RP conditions. High separation efficiency (about 125 200 plates/m) was obtained by using these new types of columns.
The effect of the physical matrix on accurate measurements using fixed volume analytical techniques
Authors: Brown Richard J. C. , Edwards Peter R.
Published: August 2006

In order to perform high accuracy analytical measurements most analytical techniques require some form of calibration using standards of the same quantity as that being measured. The highest accuracy calibration standards are those prepared by mass (gravimetrically) as opposed to by volume (volumetrically). The use of gravimetrically prepared standards to calibrate analytical techniques that rely on fixed volume injections can cause systematic errors, even when the analytical technique does not suffer from a chemical matrix interference. The origin of these errors is explained and is demonstrated experimentally for the analysis of sulphate in synthetic seawater samples, and the measurement of the anionic content of particulate matter following extraction with water and wetting agents; where average measurement biases of +2.7 and –3.2%, respectively, were observed. Proposals are offered for methods to overcome this ‘physical matrix effect’.
Knowledge exploitation, knowledge exploration, and competency trap
Authors: Liu Weiping
Published: August 2006

It is no surprise that knowledge exploitation and knowledge exploration have become the consistent theme in organizational learning literature. Strategy and organization theorists have similarly observed the dynamic capabilities anchored in a firm's ability to simultaneously exploit current technologies and resources to secure efficiency benefits, and creating variation through exploratory innovation. While some studies argue that excessive exploration or excessive exploitation can lead to a competency trap, the ‘competency trap’ component actually has received less empirical scrutiny. This paper provides a study about how competency traps are formed in the process of knowledge exploration and exploitation as well as their effects on business performance.

The paper includes three main sections: First, the theoretical interpretation of the ‘competency trap’ construct is broadened by investigating the formation of competency traps based on organizational learning theory; second, factors leading to the formation of different competency traps are identified; and third, the relationship between an organization's competency trap and business performance is investigated. The article ends with a discussion of implications for the organizational learning literature. Copyright © 2006 John Wiley & Sons, Ltd.
Dynamic capabilities in early‐phase entrepreneurship
Authors: Boccardelli Paolo , Magnusson Mats G.
Published: August 2006

The dynamic capabilities perspective has received increasing attention in the field of strategic management research. By focusing not only on the competitive advantage that is provided by a certain resource constellation, but also on the change of firms' resources over time to fit changing business environments, this perspective underlines the strategic importance of innovation. Despite the apparent interest in the dynamics of firm resources, there is still limited empirical evidence for how the strategic matching of resources and market needs is actually done, particularly in more rapidly changing environments. In order to investigate this process, an empirical study of 59 start‐ups in the Swedish mobile Internet industry was performed. A first finding from the study is that start‐ups which change market focus have a significantly higher probability to survive their first years. Furthermore, it is seen that in most cases, the change in market focus takes place without any related change in the technological resources that are used by the firm, indicating that an important factor at this stage is the flexible use of resources in searching for a suitable match between resources and market opportunities. This mode of learning and adaptation is very different from earlier proposed models focusing on the acquisition and transformation of resources. Instead, the early‐stage dynamic capabilities reveal themselves as bricolage, that is, the capacity to re‐interpret and re‐combine already existing resources and thereby improve their fit with the demands of the market environment. The results suggest that earlier proposed dynamic capabilities frameworks need to be modified, by taking into account the single entrepreneur as a source of dynamic capabilities, and by introducing the concept of resource flexibility. In terms of managerial implications, the findings underline the importance for entrepreneurs to balance the striving for distinctive capabilities that provide competitive advantage and the experimentation and improvisation needed to adapt to changes in the market. Copyright © 2006 John Wiley & Sons, Ltd.
The relationship between innovation and business performance—a comparative study between manufacturing and service firms
Authors: Prajogo Daniel I.
Published: August 2006

This paper explores the relationship between innovation performance (in terms of product and process) and business performance (sales growth, market share and profitability) and compares this relationship between manufacturing and service firms. This study was driven by the lack of studies on innovation in service sectors despite the importance of innovation as one of the primary sources of competitive advantage. Furthermore, as manufacturing firms and service firms are different in many respects, including innovation performance, it could be expected that manufacturing firms could pursue and emphasise different aspects of innovation than their service counterparts. Empirical data was gathered from 194 managers in Australian firms, with nearly equal proportion drawn from the manufacturing and service sectors (52% and 47% respectively). Several major findings were found through data analysis. First, there was no significant difference between manufacturing and service firms in both product and process innovation performance. The second finding, however, indicated a stronger correlation existed for manufacturing firms than for service firms between innovation and business performance, particularly in relation to process innovation. Third, it was found that process innovation shows a relatively stronger relationship with business performance than product innovation in manufacturing sectors. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and Optical Properties of Dendronized Porphyrin Polymers
Authors: Li Binsong , Fu Yaqin , Han Yang , Bo Zhishan
Published: August 2006

Summary: A novel kind of dendronized porphyrin polymers was synthesized by Sonogashira coupling of diethynyl‐functionalized porphyrin monomers and diiodo‐functionalized macromonomers bearing Fréchet‐type dendrons. The encapsulation of red‐light‐emitting porphyrin‐containing conjugated backbones into dendronized polymers can not only reduce the aggregation of polymer backbones and the self‐quenching of their fluorescence but also endow the porphyrin polymers with good solubility. We also report the optical and electrochemical properties of the porphyrin‐containing dendronized polymers.

Synthesis of a novel kind of dendronized porphyrin polymers by Sonogashira coupling of diethynyl‐functionalized porphyrin monomers and diiodo‐functionalized dendritic macromonomers.

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Synthesis of a novel kind of dendronized porphyrin polymers by Sonogashira coupling of diethynyl‐functionalized porphyrin monomers and diiodo‐functionalized dendritic macromonomers.
Thermoreversible Ferrogels
Authors: Lattermann Günter , Krekhova Marina
Published: August 2006

Summary: For the first time, thermoreversible ferrogels (FG) by physical gelation of ferrofluids have been described. Finavestan A80B paraffin oil in a concentration range of the gelator KRATON G‐1650 with Cgelator = 3–10 wt.‐%, was used to obtain stable and homogeneous FGs. TEM micrographs revealed that the magnetite particles are preferably located in the ‘free’ paraffin phase between micellar domains of the gelator. So, the magnetite nanoparticles make visible a ‘negative’ picture of the structure of the micellar domains of the gel, which is observed in the pure gel as a ‘positive’ image. The mean diameter of the polystyrene cores is $\overline d$ = 17 nm, and that of the magnetite particles is $\overline d$ = 7 nm.

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Modeling of Diffusion Limitations in Bulk RAFT Polymerization
Authors: Peklak A. David , Butté Alessandro
Published: August 2006

Summary: The impact of diffusion limitations on RAFT polymerizations is investigated in this work. In particular, two models are compared: one accounting for diffusion limitations by using average chain lengths, the other accounting for the entire CLD. It is shown that such a description is necessary to correctly predict the kinetics of polymerization processes, as well as the evolution of average chain length and polydispersity. For properly selected study cases, differing conversion curves are obtained above 40% monomer conversion, if only average values of the CLD are considered. The same is valid for the calculation of the polydispersity, which starts differing above 80% conversion. Finally, for given conditions of diffusion limitations, it is found that an ideal polydispersity can be defined and it is shown that the polydispersity tends to this characteristic value during the entire evolution of the polymerization process.

$k_{\rm t}^{{\rm CLD}} /k_{\rm t}^{{\rm DP}}$ as a function of f for various values of $\overline {DP} _n^{\rm R} /\overline {DP} _{{\rm crit}}$.

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$k_{\rm t}^{{\rm CLD}} /k_{\rm t}^{{\rm DP}}$ as a function of f for various values of $\overline {DP} _n^{\rm R} /\overline {DP} _{{\rm crit}}$.
Effect of Pressure on the Miscibility of Polyethylene/Poly(ethylene‐alt‐propylene) Blends
Authors: Choi Phillip , Rane Sagar S. , Mattice Wayne L.
Published: August 2006

Summary: Effect of density, and hence pressure, on the miscibility of a 50:50 mol/mol PE/PEP blend was studied using a coarse‐grained MC simulation approach on a high‐coordination lattice, with the conformations of the coarse‐grained chains constrained by the RIS model. Interchain pair correlation functions are used to assess the miscibility of the mixtures. Miscibility increases with increasing temperature over the range −50–150 °C. It is rather insensitive to pressure at high temperatures, but at −50 °C, the blend miscibility increases with decreasing pressure. The findings are consistent with the fact that the blend is an UCST blend and that the simulation temperatures used, except −50 °C, were considerably higher than the UCST of the blend. The pressure dependence of the blend miscibility observed near −50 °C is also in agreement with the experimental observation that the blend exhibits a negative volume change of mixing. The present work demonstrates that the coarse‐grained MC approach, when it is used with periodic boundary cells of different sizes filled with the same number of chains, is capable of capturing the pressure dependence of UCST blends. In addition, such a simulation also provides us with insights about the molecular origin of the observed pressure dependence of miscibility. In the present case, the segregation of PE and PEP chains at low temperatures and high pressure simply originates from the fact that fully extended segments of PE chains tend to cluster so that their intermolecular interactions can be maximized. As the temperature increases, there is a decrease in the probability of a trans state at a CC bond in PE, and therefore the attraction between the PE chains is reduced at higher temperatures, promoting miscibility and the UCST behavior.

Density (pressure) dependence of the 2nd shell pair correlation function values for a 50/50 PE/PEP blend at −50 °C.

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Density (pressure) dependence of the 2nd shell pair correlation function values for a 50/50 PE/PEP blend at −50 °C.
Directed assembly of copolymer materials on patterned substrates: Balance of simple symmetries in complex structures
Authors: Daoulas Kostas Ch. , Müller Marcus , Stoykovich Mark P. , Papakonstantopoulos Yioryos J. , de Pablo Juan J. , Nealey Paul F. , Park Sang‐Min , Solak Harun H.
Published: August 2006

The self‐assembly of a lamella‐forming blend of a diblock copolymer and its respective homopolymers on periodically patterned substrates is investigated by a concerted experimental and theoretical approach. The substrate pattern consists of square arrays of spots that preferentially attract one component of the blend. The mismatch between the lamellar equilibrium morphology of the copolymer material and the substrate pattern results in the formation of a bicontinuous morphology. At the substrate, a quadratically perforated lamella (QPL) assembles in perfect registry with the substrate pattern. From this, QPL necks emanate and reach the top surface of the film. The detailed structure of these cylindrical nanochannels is analyzed using Voronoi tessellation, orientation correlation functions, and the structure factor of the neck positions on the top surface. The surface morphology is dictated by the antagonism of the square symmetry of the substrate pattern and the tendency of the necks to locally pack in a hexagonal arrangement. The analogy and differences to a system of adsorbed monolayer on corrugated substrates is explored by comparing the arrangement of the necks on the film's top surface with the structure of a soft disk model on a quadratically corrugated substrate. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2589–2604, 2006
Interplay of magnetism and superconductivity
Authors: Akhavan M.
Published: August 2006

After about two decades of intense research since the discovery of high‐temperature superconductivity (HTSC) in cuprates, although many aspects of the physics and chemistry of these cuprate superconductors are now well understood, the underlying pairing mechanism remains elusive. Magnetism and superconductivity are usually thought as incompatible, but in number of special materials including HTSCs these two mutually excluding mechanisms are found to coexist. The presence in a system of superconductivity and magnetism, gives rise to a large number of interesting phenomenon. This article provides perspective on recent developments and their implications for our understanding of the interplay between magnetism and superconductivity in new materials. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurements and analysis of the noise spectral density of YBCO films
Authors: Taoufik A. , Bghour M. , Labrag A. , Bouaaddi A. , Abaragh A. , Ramzi A. , Senoussi S. , Tirbiyine A.
Published: August 2006

We studied the voltage noise spectral density S V(f, T, H ) dependence on frequency f, temperature T and applied magnetic field H in YBa2Cu3O7–δ films. The voltage noise spectral density S V(f ) as a function of frequency exhibits 1/f behavior according to a Lorentzian shape A [(1 + πf /f 0)B ]C, where A, f 0, B, C constants which are determined and compared for many values of H . The influence of temperature and magnetic field is clearly observed as a function of temperature, S V(T ) is found to vanish at T g, the temperature of vortex glass transition, according to a (T – T g)x law. We interpreted those results by the formation of a large distribution of glass vortex domains. Approaching T g, these domains grow in size and lifetime, while at T g those parameters diverge. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polymerization processes in Al(OBus)3 sol‐gel solutions: an investigation by laser desorption/ionization mass spectrometry
Authors: Zangrando Roberta , Armelao Lidia , Bottaro Gregorio , Gross Silvia , Seraglia Roberta , Tondello Eugenio , Traldi Pietro
Published: August 2006

The hydrolysis and polycondensation reactions of Al(OBus)3 have been studied by laser desorption/ionization (LDI), performed on the solid samples originating from different aluminum alkoxide solutions, prepared using the usual operating conditions employed in the sol‐gel synthesis of Al2O3‐based materials. CHCl3, CH3OH and CH3OH/H2O mixture were used as solvents. In the latter case different H2O/Al(OBus)3 molar ratios were adopted, i.e. 1:1, 1:2, and 1:4. The obtained hydrolysis and polycondensation species consist of polynuclear species containing ≤12 aluminum atoms. In the CHCl3 solutions, the formation of the observed hydrolysis products has been ascribed to the reaction with water present in the atmosphere during the LDI sample preparation and/or present at trace level in the solvent. When methanol is used as a solvent, extensive methanolysis reactions take place, thus originating oligomers with CH3O and OH substituents. The kinetics of formation of the various polynuclear species are dependent on the reaction environment and the reaction is faster in the presence of methanol. It is worth noticing that, regardless of the hydrolysis process, the polycondensation products can be considered as originating from a common tetrameric core [Al4O4(OBu)2(OH)2] around which different building blocks are condensed to form various oxo‐polymeric species. Copyright © 2006 John Wiley & Sons, Ltd.