bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid breakthrough into the unconscious of a depressed and masochistic patient in an initial two‐hour therapy session
Authors: Slote Gilbert M.
Published: September 2002

In this article the author presents a rapid breakthrough into the unconscious of a patient by applying Dr Habib Davanloo's Central Dynamic Sequence focusing particularly on the phases of pressure and challenge leading to a crystallization of the patient's defenses in the transference. Technical interventions to exert pressure and challenge in the transference are presented as well as the types of defenses these interventions are intended to counteract. Each intervention by the therapist, and the corresponding response of the patient is analyzed. Copyright © 2000 John Wiley & Sons, Ltd.
Dynamic SIMS characterization of interface structure of Ag/Alq3/NPB/ITO model devices
Authors: Song Weijie , Li Zhanping , So S. K. , Qiu Yong , Zhu Youngfa , Cao Lili
Published: September 2002

In this study, we first profiled model organic light‐emitting diodes (OLEDs) with the structure Ag/tris(8‐hydroxyquinoline) aluminium (Alq3)/N,N′‐diphenyl‐N,N′‐bis[1‐naphthyl‐(1,1′‐biphenyl]‐4,4′‐diamine (NPB)/indium tin oxide (ITO) using dynamic SIMS. The element distribution across the multilayer and the dynamic SIMS spectra at different regions were obtained. It was shown that dynamic SIMS is a powerful tool in profiling OLEDs. Clear diffusion of Ag into the Alq3 layer was observed. The experimental results also revealed that a distinct interface for Alq3/NPB can be obtained using dynamic SIMS. Copyright © 2001 John Wiley & Sons, Ltd.
XPS characterization of zeolite catalyst in plasma catalytic methane conversion
Authors: He Fei , Liu Chang‐jun , Eliasson Baldur , Xue Bingzhang
Published: September 2002

Direct plasma methane conversion to higher hydrocarbons using pure methane feed is almost impossible without using zeolite. In the presence of zeolite, such direct conversion leads to a very high yield of higher hydrocarbons. The use of zeolite not only inhibits the formation of non‐selective carbon black and plasma‐polymerized films but also significantly increases the selectivity of light hydrocarbons during plasma methane conversion with dielectric barrier discharge (DBD). The DBD plasma‐used zeolite has been characterized by x‐ray photoelectron spectroscopy (XPS) and suggests the DBD plasmas have led to reactions within the channel of zeolite. The present investigation gives us more supporting results for the proposed mechanism of plasma‐promoted catalysis. Copyright © 2001 John Wiley & Sons, Ltd.
Temperature‐programmed surface reaction study on C2‐oxygenate synthesis over SiO2 and nanoporous zeolitic material supported Rh–Mn catalysts
Authors: Ma Hongtao , Yuan Zhongyong , Wang Yi , Bao Xinhe
Published: September 2002

Temperature‐programmed surface reaction (TPSR), temperature‐programmed reaction (TPR) and temperature‐programmed desorption (TPD) were used to study the synthesis of C2‐oxygenates from syngas over Rh–Mn‐based catalysts supported on amorphous silica and mesoporous MCM‐41 supports. Both TPD and TPSR reveal the existence of several different kinds of CO species on the catalyst surface in the course of the catalytic reaction (linear, geminal, bridged and tilt‐adsorbed CO species) but only the bridged form and tilt‐adsorbed CO species are the precursors for CO dissociation and the formation of C2‐oxygenates. The formation temperature of acetaldehyde is higher than that of ethanol, which suggests that they may be formed via different mechanisms. The ethanol formation activity over the Rh–Mn/MCM‐41 catalyst is lower than that over the Rh–Mn/SiO2, which suggests that the number of active sites for ethanol formation are fewer on the surface of Rh–Mn/MCM‐41. However, the acetaldehyde formation activities are almost identical for the Rh–Mn catalysts supported on amorphous SiO2 and MCM‐41, meaning that acetaldehyde and ethanol might be formed on different active sites. Copyright © 2001 John Wiley & Sons, Ltd.
Theoretical study of the effects of intermolecular interactions in self‐assembled long‐chain alkanes adsorbed on graphite surface
Authors: Yin Shuxia , Wang Chen , Qiu Xiaohui , Xu Bo , Bai Chunli
Published: September 2002

In this paper, we studied the physisorption of long‐chain alkanes CnH2n+2 (n = 8, 16, 24, 34) on a graphite surface using molecular mechanics simulations. The computed results illustrated that the interactions between adsorbed molecules and substrate are dominated by van der Waals forces whereas the electrostatic interactions are very small. It was found that the ratio of the alkane molecule–molecule interactions (two‐dimensional crystallization energy) to the interactions between alkane and graphite (adsorption energy) ranges from ∼2 : 5 to 3 : 5. The adsorption stability and immobility of the alkanes increases proportionally with an increase in the chain length. It was concluded that the lateral interactions between adsorbed molecules are important to the formation of ordered two‐dimensional lamellae. The theoretical results support the scanning tunneling microscopy (STM) observation of alkylated aromatic compounds on a graphite surface. Copyright © 2001 John Wiley & Sons, Ltd.
Application of focused ion beam lift‐out specimen preparation to TEM, SEM, STEM, AES and SIMS analysis
Authors: Stevie F. A. , Vartuli C. B. , Giannuzzi L. A. , Shofner T. L. , Brown S. R. , Rossie B. , Hillion F. , Mills R. H. , Antonell M. , Irwin R. B. , Purcell B. M.
Published: September 2002

Commercially available focused ion beam (FIB) workstations with spatial resolution of 5–7 nm can prepare specimens with excellent lateral resolution. This capability has been utilized extensively by the semiconductor industry to obtain materials characterization from continually smaller areas. The FIB has been adopted generally as a preparation tool for scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ability to prepare site‐specific specimens that can be removed from the bulk of a sample provides enhanced SEM and TEM analyses and new approaches for other analytical tools. Dedicated scanning transmission electron microscopy (STEM) can provide images through samples several micrometers thick. Auger electron spectroscopy (AES) can analyze with improved ability to identify a small particle. Secondary ion mass spectrometry (SIMS) can provide trace analysis at high mass resolution. Automatic operation of FIB workstations permits the creation of multiple lift‐out samples without the presence of an operator. Copyright © 2001 John Wiley & Sons, Ltd.
ToF‐SIMS study of the surface morphology of blends of polystyrene and poly(N‐vinyl‐2‐pyrrolidone) compatibilized by poly(styrene‐co‐4‐vinylphenol)
Authors: Zeng X. M. , Weng L. T. , Li L. , Chan C.‐M. , Liu S. Y. , Jiang M.
Published: September 2002

The influence of the vinylphenol content of poly(styrene‐co‐4‐vinylphenol) (STVPh) on the surface morphology of a blend of polystyrene (PS) and poly(N‐vinyl‐2‐pyrrolidone) (PVP) was investigated by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) chemical imaging. The images obtained through the use of the ToF‐SIMS positive total ions and selected negative ions clearly show that the characteristic size of the dispersed phase (PVP) decreased with the addition of the STVPh‐5 (5 mol.% vinylphenol) random copolymer. The spectra obtained retrospectively from the matrix and the dispersed phase indicated that the matrix phase was very similar to the pure PS and that the dispersed phase was very similar to the pure PVP. The addition of the STVPh‐9 random copolymer to the blend of PS and PVP resulted in a totally different morphology: both PVP and PS became semi‐continuous and the dispersed particles are much larger. The morphological changes were caused by the formation of a single phase between PVP and STVPh‐9 due to an increase in the density of the hydrogen bond formed between PVP and STVPh‐9. When the vinylphenol content was <2 mol.%, the particle size of the PVP‐rich phase stayed the same. The compatibilizing effect was much weakened as the concentration of STVPh‐5 decreased to 1 wt.%. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of potentiostatic current transients at metal/liquid interfaces: resolving the effects of a finite step interval
Authors: Garland J. E. , Pettit C. M. , Walters M. J. , Roy D.
Published: September 2002

Potentiostatic current transients are used routinely for electrochemical analysis of metal/liquid interfaces. These measurements can be affected by both the electrochemical cell and the potentiostat used for such experiments. We demonstrate this in the present report with double‐layer charging experiments using a gold electrode in aqueous electrolytes of NaF and NaNO3. By employing a high‐resolution potentiostat, we show that the apparently instantaneous voltage step actually has a finite temporal width. The double‐layer charging current develops an additional feature due to this behavior of the voltage step. We present a theoretical framework to resolve these instrumental effects from the actual electrical response of the double layer. The results are compared with a set of independent measurements of the same quantities using impedance spectroscopy. Copyright © 2001 John Wiley & Sons, Ltd.
Innovative sample preparation for GDOES analysis of decarburized layers in cylindrical metal specimens
Authors: Bellini S. , Cilia M. , Piccolo E. Lo
Published: September 2002

Glow discharge optical emission spectrometry (GDOES) is a technique widely used for depth profile analysis but there are two significant limitations: samples must have planar surfaces and profile analysis generally cannot go beyond a depth of 100 µm. A new method of sample preparation has been developed to overcome both of these limitations, consisting of plastic deformation of the curved sample by pressing it until a planar surface is obtained. Furthermore, after profile analysis, the surface surrounding the glow‐discharged zone of the sample is ground to obtain a uniform layer levelled down to the bottom of the crater. Repeated grinding operations and profile analyses allow analysis of samples with practically unlimited thickness. An application of this method to determine the entity of the decarburized layer on a carbon steel rod sample is described in this paper. Copyright © 2001 John Wiley & Sons, Ltd.
Apatite films produced by electrodeposition: characterization by TEM and AFM
Authors: Manso Miguel , Jiménez Carmen , Morant Carmen , Herrero Pilar , Martínez‐Duart J. M.
Published: September 2002

Apatite films have been grown by a method involving both physical and chemical processes. The spontaneous nucleation of apatite crystals on the surface of Ti/Si and Si substrates was activated by applying positive constant potentials. The surface morphology and microstructure of these films have been studied. Several apatite‐like nanocrystals have been observed in the bulk by high‐resolution transmission electron microscopy. We also observed ordered structures with atomic resolution on the surface using atomic force microscopy. The results of the combined characterization suggest that this is a useful technique for low‐temperature deposition of thin apatite films on both semiconductor and metallic substrates. Copyright © 2001 John Wiley & Sons, Ltd.
Surface modification of a silicate glass during XPS experiments
Authors: Sharma A. , Jain H. , Miller A. C.
Published: September 2002

The surface chemistry of a commercial soda‐lime silicate glass is shown to change during a long‐duration XPS experiment wherein the glass surface was exposed to the monochromatic x‐rays and low‐energy electrons (0.2–5 eV) that compensate for the charging of the surface. The atomic percentage of sodium increases and that of oxygen decreases with increasing time of the experiment. The separate influence of x‐rays and the low‐energy electrons on the glass surface is also measured. The results show that diffusion of the sodium ions is enhanced more in the presence of x‐rays than in the presence of low‐energy electrons. All observations can be explained well by a model that considers the breaking of the bridging and non‐bridging oxygen bonds, and the trapping of photoelectrons and the externally supplied electrons. Although long‐duration XPS experiments show significant changes on the exposed surface, the chemical composition of the bulk glass obtained during a short experiment agrees well with that obtained from the chemical analysis. Copyright © 2001 John Wiley & Sons, Ltd.
Use of Auger parameter and Wagner plot in the characterization of Cu‐ZSM‐5 catalysts
Authors: Moretti Giuliano , Filippone Francesco , Satta Mauro
Published: September 2002

The use of the Auger parameter, the Wagner plot and a simple electrostatic model permits the determination of the local electronic and geometrical structure of Cu+ sites in Cu‐ZSM‐5 catalysts. The results are in agreement with previous extended X‐ray absorption fine structure (EXAFS) and X‐ray absorption near‐edge structure (XANES) studies. Copyright © 2001 John Wiley & Sons, Ltd.
Use of XPS for the study of cerium–vanadium (electrochromic) mixed oxides
Authors: Salvi A. M. , Decker F. , Varsano F. , Speranza G.
Published: September 2002

Research studies on new materials have shown that cerium–vanadium mixed oxides have potential for use as counter‐electrodes in electrochromic devices owing to the combination of the excellent stability and transparency of cerium oxides and the high ion‐storage capacity of the vanadium oxides.

Among them, cerium orthovanadate (CeVO4) has shown its potentiality as an intercalation electrode of suitable structure into which ions can be inserted reversibly, thus balancing the ion‐charge capacity required by WO3, which is the colouring electrode in electrochromic devices.

In this work, cerium–vanadium stoichiometric oxides (CeO2–V2O5, 1 : 1 molar ratio) have been used as a target material for r.f.‐sputtering thin‐film deposition onto suitable substrates. The films obtained have been characterized before and after electrochemical lithium intercalation. Their XPS and x‐ray‐induced Auger electron spectroscopy spectra have been compared with those obtained with the standard precursor oxides and the results discussed also on the basis of literature data.

In order to be able to observe the changes in chemical state and composition expected on film formation, a careful curve‐fitting procedure has been used that allows the determination of the background structure and intrinsic satellites for each peak, as reported already in previous papers. Copyright © 2001 John Wiley & Sons, Ltd.
Line structure in photoelectron and Auger electron spectra of CuOx/Cu and Cu by Auger photoelectron coincidence spectroscopy (APECS)
Authors: Jiang Zhong‐Tao , Thurgate Stephen M. , Wilkie Peter
Published: September 2002

In this study, we present Cu L3M45M45 Auger spectra in coincidence with Cu 2p3/2 from the oxidized surface of Cu (i.e. CuOx/Cu) and Cu 2p3/2 lines in coincidence with Auger 1G and 3F terms of Cu L3VV from Cu. Comparison of the L3VV line structures of CuOx/Cu with that of Cu reveals that the Auger line has changed to band‐like in the CuOx/Cu material. The reduced mean free path of the Auger electron in coincidence with the photoelectron displays the Auger line of the CuOx surface. The asymmetric broadening of the Cu 2p3/2 lines in coincidence with 1G and 3F terms from Cu illustrates that a single‐step model is essential for describing the Auger lineshape of copper. Copyright © 2001 John Wiley & Sons, Ltd.
Molecular dynamics simulation of the cluster‐ impact‐induced molecular desorption process
Authors: Webb Roger , Kerford Michelle , Ali Elliot , Dunn Michelle , Knowles Luke , Lee Kenneth , Mistry Jitesh , Whitefoot Francis
Published: September 2002

Molecular dynamics computer simulation is used to investigate the effects of cluster surface interactions and their use to desorb molecules from a surface. Of interest here is the interaction of fullerenes with a graphite surface and in particular cluster impact desorption of adsorbed molecules from the graphite surface.

It has been shown recently how impacts from fullerenes on graphite cause an acoustic wave to propagate across the surface from the impact site. In the work presented here it is shown that this wave can be used to desorb intact molecules that are weakly bonded by Van der Waals forces to the surface. The ultimate objective is to desorb molecules the size of genes. Using C60, a wave can be created that is strong enough to desorb 15 benzene molecules without breaking either the surface of the graphite or any of the benzene molecules. It is unlikely that this will be strong enough to desorb a high‐mass gene. By increasing the initial energy of the C60, we desorb a larger number of molecules but at the expense of breaking the surface, losing the coherence of the acoustic wave and breaking many of the benzene molecules. However, if the size of the impacting molecule is increased to that of a 300‐particle ‘onion’‐type structure, it is possible to increase greatly the power of the acoustic wave, thereby desorbing many more benzene molecules from the surface without causing any damage to the surface, the fullerene or to the benzene molecules themselves. Copyright © 2001 John Wiley & Sons, Ltd.
Bioengineered material surfaces for medical applications
Authors: Mathieu Hans Jörg
Published: September 2002

Man‐made materials are increasingly being applied as substitutes for defective functions in human hosts. These biomaterials may be non‐viable materials used in medical devices interacting with biological systems. Such engineered materials should be biocompatible, i.e. with minimal non‐specific protein adsorption. This paper describes the functionalization of soft biomaterial surfaces and diamond‐covered silicon wafers controlled by surface spectroscopies such as x‐ray photoelectron spectroscopy (XPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), as well as contact angle measurements and scanning force microscopy (SFM). Surface functionalization is obtained with molecules such as phosphorylcholine, carbohydrates, dextran or peptides added to various soft and hard materials. Surface analytical tools are able to control the chemistry, energy and topography of surfaces and thin films with high sensitivity down to the femtomole range and nanometer resolution. Copyright © 2001 John Wiley & Sons, Ltd.
Chromosomal fragile sites and relationship between genetic predisposition to small cell lung cancer
Authors: Karadağ M. , Tunca B. , Çeçener G. , Egeli Ü. , Özyardimci N. , Ege E. , Gözü O.
Published: September 2002

Fragile sites are non‐staining gaps and breaks on mammalian chromosomes. Several investigators have pointed out that these sites may act as factors that predispose to specific chromosomal rearrangements that are present in some cancer cases. The expression of common fragile sites induced by aphidicolin (Apc) was evaluated on prometaphase chromosomes obtained from the peripheral blood lymphocytes of 15 patients with lung cancer, 20 of their clinically healthy family members, and 20 age‐matched normal controls. As a result of cytogenetic evaluation carried out by the High Resolution Banding (HRB) technique, 1q21, 2q33, 3p14, 7q32, 13q13, 16q23, 17q21, and 22q12 are defined as fragile sites in patients and relatives. The rate of total fragile sites and 2q33, 3p14, and 16q23 are statistically significant in both patients and relatives when compared with the control group. Therefore, our results showed that common fragile sites might be unstable factors in the human genome and they can be used as suitable markers for genetic predisposition to lung cancer. Teratogenesis Carcinog. Mutagen. 22:31–40, 2002. © 2002 Wiley‐Liss, Inc.
Inhibition of telomerase activity in endometrial cancer cells by selenium‐cisplatin conjugate despite suppression of its DNA‐damaging activity by sodium ascorbate
Authors: Błasiak Janusz , Kadłubek Magdalena , Kowalik Joanna , Romanowicz‐Makowska Hanna , Pertyński Tomasz
Published: September 2002

Telomerase activation can be considered as a critical step in cell immortalization. The enzyme elongates or maintains telomere length by adding to its end tandem TTAGGG repeats by using its endogenous RNA template. Telomerase is not detectable in most somatic cells but is upregulated in germ line cells and in 85–90% of human cancers, which suggests important role of telomerase in neoplastic transformation. Consequently, telomerase has been proposed as a potentially highly selective target for the development of antiproliferative agents. Platinum complexes are widely administrated in cancer therapy. A conjugate of selenite with diammineplatinum [(NH3)2Pt(SeO3)2] is a novel potential anticancer drug. Using alkaline single cell gel electrophoresis (comet assay), we showed that the drug at 5–30 μM induced concentration‐dependent damage to DNA of endometrial cancer cells derived from tumor samples. Sodium ascorbate at 10 and 50 μM reduced the extent of the DNA damage evoked by the drug. (NH3)2Pt(SeO3) reduced telomerase activity in the cells in a concentration‐dependent manner as measured by using the telomere repeat amplification protocol (TRAP) assay. This effect was independent of sodium ascorbate. Therefore, mutagenic effects of the conjugate can be reduced by well‐recognized antimutagen, sodium ascorbate, but it can still retain ability to affect neoplastic transformation. The results obtained indicate that (NH3)2Pt(SeO3) may specifically inhibit telomerase activity in endometrial cancer cells. Teratogenesis Carcinog. Mutagen. 22:73–82, 2002. © 2002 Wiley‐Liss, Inc.
Syntheses of semiconductor nanoparticles using single‐molecular precursors
Authors: Pickett Nigel L. , O’Brien Paul
Published: September 2002

Methods for the preparation of II‐VI, III‐V, and II‐V as well as other compound semiconductor nanoparticles using main group single‐molecular precursors have been developed. The work involves the design and synthesis of compounds containing all the elements required within the desired nanoparticulate material. Precursors are tailored to give reproducible, clean decomposition at moderate temperatures, leading to high quality, defect free, mono‐dispersed nanoparticles. In this article we cover key aspects of precursor and nanoparticle synthesis. One of the more successful and reproducible series of single‐source precursors used, and the one on which we have concentrated our research efforts, is the bis(dialkyldithio‐/diseleno‐carbamato)cadmium(II)/zinc(II) compounds, M(E2CNR2)2 (M = Zn or Cd, E = S or Se, and R = alkyl) for the preparation of chalcogenide nanoparticulate materials. Preliminary mechanistic studies suggest that the precursor to nanoparticle deposition route is strongly influenced by the alkyl substituent groups present, and may well determine the phase and quality of the final metal chalcogenide nanoparticles produced. Herein we discuss the synthesis of semiconductor nanoparticles using such single‐molecular precursors. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:467–479, 2001
Weak interactions and molecular recognition in systems involving electron transfer proteins
Authors: Hirota Shun , Yamauchi Osamu
Published: September 2002

Electrostatic interactions and other weak interactions between amino acid side chains on protein surfaces play important roles in molecular recognition, and the mechanism of their intermolecular interactions has gained much interest. We established that charged peptides are useful for investigating the molecular recognition character of proteins and their molecular interaction induced structural changes. Positively charged lysine peptides competitively inhibited electron transfer from reduced cytochrome f (cyt f) or cytochrome c (cyt c) to oxidized plastocyanin (PC), due to neutralization of the negatively charged site of PC by formation of PC–lysine peptide complexes. Lysine peptides also inhibited electron transfer from cyt c to cytochrome c peroxidase. Likewise, negatively charged aspartic acid peptides interacted with the positively charged sites of cyt f and cyt c, and competitively inhibited electron transfer from reduced cyt f or cyt c to oxidized PC and from [Fe(CN)6]4– to oxidized cyt c. Changes in the geometry and a shift to a higher redox potential of the active site Cu of PC on oligolysine binding were detected by spectroscopic and electrochemical measurements, owing to the absence of absorption in the visible region for lysine peptides. Structural and redox potential changes were also observed for cyt f and cyt c by interaction with aspartic acid peptides. ©2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:290–299, 2001
Science enrichment programs for gifted high school girls and boys: Predictors of program impact on science confidence and motivation*
Authors: Stake Jayne E. , Mares Kenneth R.
Published: September 2002

The impact of two science enrichment programs on the science attitudes of 330 gifted high school students was evaluated using a multimethod, multiperspective approach that provided a more comprehensive evaluation of program impact on science attitudes than did previous assessments of science programs. Although pre–post comparisons did not indicate positive impact on science attitudes, other measures provided strong evidence of program effectiveness. Program benefits were greater among girls, those who had more supportive families and teachers, and those who entered the programs with greater general confidence in their abilities. Implications for science enrichment programs and their evaluation are discussed. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 1065–1088, 2001
The black–white “achievement gap” as a perennial challenge of urban science education: A sociocultural and historical overview with implications for research and practice*
Authors: Norman Obed , Ault Charles R. , Bentz Bonnie , Meskimen Lloyd
Published: September 2002

A perennial challenge for urban education in the United States is finding effective ways to address the academic achievement gap between African American and White students. There is widespread and justified concern about the persistence of this achievement gap. In fact, historical evidence suggests that this achievement gap has existed at various times for groups other than African Americans. What conditions prevailed when this achievement gap existed for these other groups? Conversely, under what conditions did the gap diminish and eventually disappear for these groups? This article explores how sociocultural factors involved in the manifestation and eventual disappearance of the gap for these groups may shed some light on how to address the achievement gap for African American students in urban science classrooms. Our conclusion is that the sociocultural position of groups is crucial to understanding and interpreting the scholastic performance of students from various backgrounds. We argue for a research framework and the exploration of research questions incorporating insights from Ogbu's cultural, ecological theory, as well as goal theory, and identity theory. We present these as theories that essentially focus on student responses to societal disparities. Our ultimate goal is to define the problem more clearly and contribute to the development of research‐based classroom practices that will be effective in reducing and eventually eliminating the achievement gap. We identify the many gaps in society and the schools that need to be addressed in order to find effective solutions to the problem of the achievement gap. Finally, we propose that by understanding the genesis of the gap and developing strategies to harness the students' responses to societal disparities, learning can be maximized and the achievement gap can be significantly reduced, if not eliminated entirely, in urban science classrooms. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 1101–1114, 2001
Case‐based pedagogy as a context for collaborative inquiry in the Philippines
Authors: Arellano Elvira L. , Barcenal Tessie L. , Bilbao Purita P. , Castellano Merilin A. , Nichols Sharon , Tippins Deborah J.
Published: September 2002

The purpose of this study was to investigate the potential for using case‐based pedagogy as a context for collaborative inquiry into the teaching and learning of elementary science. The context for this study was the elementary science teacher preparation program at West Visayas State University on the the island of Panay in Iloilo City, the Philippines. In this context, triple linguistic conventions involving the interactions of the local Ilonggo dialect, the national language of Philipino (predominantly Tagalog) and English create unique challenges for science teachers. Participants in the study included six elementary student teachers, their respective critic teachers and a research team composed of four Filipino and two U.S. science teacher educators. Two teacher‐generated case narratives serve as the centerpiece for deliberation, around which we highlight key tensions that reflect both the struggles and positive aspects of teacher learning that took place. Theoretical perspectives drawn from assumptions underlying the use of case‐based pedagogy and scholarship surrounding the community metaphor as a referent for science education curriculum inquiry influenced our understanding of tensions at the intersection of re‐presentation of science, authority of knowledge, and professional practice, at the intersection of not shared language, explicit moral codes, and indigenization, and at the intersection of identity and dilemmas in science teaching. Implications of this study are discussed with respect to the building of science teacher learning communities in both local and global contexts of reform. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 502–528, 2001
Interpretive investigation of the science‐related career decisions of three African‐American college students
Authors: Lewis Bradford F. , Collins Angelo
Published: September 2002

Reports published since 1977 indicate that African Americans are underrepresented among Ph.D.‐holding scientists. Although researchers have identified numerous factors that correlate with career choice, they have failed to address students' reasons for choosing or not choosing science and science‐related careers. This study examines the career decisions of three African‐American college students. All three students began college aspiring toward science‐related careers. However, by the end of data collection only one student was working toward a science‐related career. Data were collected by means of eight, open‐ended, 1‐hour interviews conducted over a period of 6 months. Findings indicate that students' interest in a science‐related career is directly related to the degree to which they perceive that career as being supportive of deep‐seated life goals; and that a deeper view of the nature of science better enables students to perceive a science‐related career as supportive of life goals. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 599–621, 2001
Maternal diabetes: An independent risk factor for major cardiovascular malformations with increased mortality of affected infants
Authors: Loffredo Christopher A. , Wilson P. David , Ferencz Charlotte
Published: September 2002

Background

Intensive medical care of women with diabetes has reduced their risks of bearing infants with congenital anomalies. To assess the preventive potential of preconceptional care, the data of a population‐based study of cardiovascular malformations (CVM) were analyzed to determine the morphogenetic specificity of maternal diabetes risks, the morbidity and mortality of the infants, and maternal characteristics that might affect these risks.

Methods

The Baltimore‐Washington Infant Study was a case‐control study (1981‐1989) that included all live born infants with confirmed CVM; control infants were a representative sample of the birth cohort. A questionnaire administered in home visits recorded parental information on social, medical, occupational, and environmental factors. For these analyses of preconceptional diabetes risks, the case group excluded chromosomal and mendelian disorders and was divided into 3 developmental categories and 12 diagnostic groups.

Results

Preconceptional maternal diabetes was strongly associated with CVM of early embryonic origin (odds ratio [OR] = 4.7, 95% confidence interval [CI] 2.8–7.9) and with cardiomyopathy (OR = 15.1, 95% CI 5.5–41.3), but not with obstructive and shunting defects (OR = 1.4, 95% CI 0.7–3.0). There was heterogeneity within these developmental categories: among laterality defects, diabetes was associated only with cardiovisceral and atrioventricular discordance (OR = 10.0, 95% CI 3.7–27.0); among outflow tract anomalies, the risk was strongly associated with normally related great arteries (OR = 6.6, 95% CI 3.2–13.3) but not with simple transpositions; and among atrioventricular septal defects, diabetes was associated with the complete but not with the partial forms (OR = 22.8, 95% CI 7.4–70.5). The association in early CVM was strongest among infants with multisystem, predominantly VACTERL, anomalies. All‐cause mortality of infants with CVM was 39% among those with diabetic mothers and 17.8% in those with nondiabetic mothers. Deceased infants of diabetic mothers were also more likely to have extracardiac anomalies (P = 0.041), to be born prematurely (P = 0.007), and to have low birth weight (P = 0.011). Multivariate analyses of maternal factors revealed no significant confounders of the diabetes associations.

Conclusions

The evidence of diabetes‐induced major cardiac defects is of urgent clinical significance. The effectiveness of early preconceptional care in the prevention of congenital anomalies has been demonstrated repeatedly. Teratology 64:98–106, 2001. © 2001 Wiley‐Liss, Inc.
Inhibitors of choline uptake and metabolism cause developmental abnormalities in neurulating mouse embryos
Authors: Fisher Melanie C. , Zeisel Steven H. , Mar Mei‐Heng , Sadler T. W.
Published: September 2002

Background

Choline is an essential nutrient in methylation, acetylcholine and phospholipid biosynthesis, and in cell signaling. The demand by an embryo or fetus for choline may place a pregnant woman and, subsequently, the developing conceptus at risk for choline deficiency.

Methods

To determine whether a disruption in choline uptake and metabolism results in developmental abnormalities, early somite staged mouse embryos were exposed in vitro to either an inhibitor of choline uptake and metabolism, 2‐dimethylaminoethanol (DMAE), or an inhibitor of phosphatidylcholine synthesis, 1‐O‐octadecyl‐2‐O‐methyl‐rac‐glycero‐3‐phosphocholine (ET‐18‐OCH3). Cell death following inhibitor exposure was investigated with LysoTracker Red and histology.

Results

Embryos exposed to 250–750 μM DMAE for 26 hr developed craniofacial hypoplasia and open neural tube defects in the forebrain, midbrain, and hindbrain regions. Embryos exposed to 125–275 μM ET‐18‐OCH3 exhibited similar defects or expansion of the brain vesicles. ET‐18‐OCH3‐affected embryos also had a distended neural tube at the posterior neuropore. Embryonic growth was reduced in embryos treated with either DMAE (375, 500, and 750 μM) or ET‐18‐OCH3 (200 and 275 μM). Whole mount staining with LysoTracker Red and histological sections showed increased areas of cell death in embryos treated with 275 μM ET‐18‐OCH3 for 6 hr, but there was no evidence of cell death in DMAE‐exposed embryos.

Conclusions

Inhibition of choline uptake and metabolism during neurulation results in growth retardation and developmental defects that affect the neural tube and face. Teratology 64:114–122, 2001. © 2001 Wiley‐Liss, Inc.
Cytosolic redox metabolism in aerobic chemostat cultures of Saccharomyces cerevisiae
Authors: Påhlman Inga‐Lill , Gustafsson Lena , Rigoulet Michel , Larsson Christer
Published: September 2002

Cytosolic redox balance has to be maintained in order to allow an enduring cellular metabolism. In other words, NADH generated in the cytosol has to be re‐oxidized back to NAD+. Aerobically this can be done by respiratory oxidation of cytosolic NADH. However, NADH is unable to cross the mitochondrial inner membrane and mechanisms are required for conveying cytosolic NADH to the mitochondrial electron transport chain. At least two such systems have proved to be functional in S. cerevisiae, the external NADH dehydrogenase (Luttik et al., 1998; Small and McAlister‐Henn, 1998) and the G3P shuttle (Larsson et al., 1998). The aim of this investigation was to study the regulation and performance of these two systems in a wild‐type strain of S. cerevisiae using aerobic glucose‐ and nitrogen‐limited chemostat cultures. The rate of cytosolic NADH formation was calculated and as expected there was a continuous increase with increasing dilution rate. However, measurements of enzyme activities and respiratory activity on isolated mitochondria revealed a diminishing capacity at elevated dilution rates for both the external NADH dehydrogenase and the G3P shuttle. This suggests that adjustment of in vivo activities of these systems to proper levels is not achieved by changes in amount of protein but rather by, for example, activation/inhibition of existing enzymes. Adenine nucleotides are well‐known allosteric regulators and both the external NADH and the G3P shuttle were sensitive to inhibition by ATP. The most severe inhibition was probably on the G3P shuttle, since one of its member proteins, Gpdp, turned out to be exceptionally sensitive to ATP. The external NADH dehydrogenase is suggested as the main system employed for oxidation of cytosolic NADH. The G3P shuttle is proposed to be of some importance at low growth rates and perhaps its real significance is only expressed during starvation conditions. Copyright © 2001 John Wiley & Sons, Ltd.
Pichia pastoris Pex14p, a phosphorylated peroxisomal membrane protein, is part of a PTS–receptor docking complex and interacts with many peroxins
Authors: Johnson Monique A. , Snyder William B. , Lin Cereghino Joan , Veenhuis Marten , Subramani Suresh , Cregg James M.
Published: September 2002

The peroxisomal protein import machinery plays a central role in the assembly of this organelle in all eukaryotes. Genes encoding components of this machinery, termed peroxins or Pex proteins, have been isolated and characterized in several yeast species and in mammals, including humans. Here we report on one of these components, Pex14p, from the methylotrophic yeast Pichia pastoris. Work in other organisms has shown that Pex14p is located on the cytoplasmic surface of the peroxisomal membrane and binds peroxisomal targeting signal (PTS) receptors carrying proteins bound for the peroxisomal matrix, results that have led to the hypothesis that Pex14p is a receptor‐docking protein. P. pastoris Pex14p (PpPex14p) behaves like an integral membrane protein, with its C‐terminus exposed on the cytosolic side of the peroxisomal membrane. PpPex14p complexes with many peroxins, including Pex3p (Snyder et al., 1999b), Pex5p, Pex7p, Pex13p, Pex17p, itself, and a previously unreported peroxin, Pex8p. A portion of Pex14p is phosphorylated, but both phosphorylated and unphosphorylated forms of Pex14p interact with several peroxins. The interactions between Pex14p and other peroxins provide clues regarding the function of Pex14p in peroxisomal protein import. Copyright © 2001 John Wiley & Sons, Ltd.
Carnitine‐dependent metabolic activities in Saccharomyces cerevisiae: three carnitine acetyltransferases are essential in a carnitine‐dependent strain
Authors: Swiegers Jan H. , Dippenaar Nola , Pretorius Isak S. , Bauer Florian F.
Published: September 2002

L‐Carnitine is required for the transfer of activated acyl‐groups across intracellular membranes in eukaryotic organisms. In Saccharomyces cerevisiae, peroxisomal membranes are impermeable to acetyl‐CoA, which is produced in the peroxisome when cells are grown on fatty acids as carbon source. In a reversible reaction catalysed by carnitine acetyltransferases (CATs), activated acetyl groups are transferred to carnitine to form acetylcarnitine which can be shuttled across membranes. Here we describe a mutant selection strategy that specifically selects for mutants affected in carnitine‐dependent metabolic activities. Complementation of three of these mutants resulted in the cloning of three CAT encoding genes: CAT2, coding for the carnitine acetyltransferase associated with the peroxisomes and the mitochondria; YAT1, coding for the carnitine acetyltransferase, which is presumably associated with the outer mitochondrial membrane, and YER024w (YAT2), which encodes a third, previously unidentified carnitine acetyltransferase. The data also show that (a) L‐carnitine and all three CATs are essential for growth on non‐fermentable carbon sources in a strain with a disrupted CIT2 gene; (b) Yat2p contributes significantly to total CAT activity when cells are grown on ethanol; and that (c) the carnitine‐dependent transfer of activated acetyl groups plays a more important role in cellular processes than previously realised. Copyright © 2001 John Wiley & Sons, Ltd.
Integrating group Delphi, fuzzy logic and expert systems for marketing strategy development: the hybridisation and its effectiveness
Authors: Li Shuliang , Davies Barry , Edwards John , Kinman Russell , Duan Yanqing
Published: September 2002

A hybrid approach for integrating group Delphi, fuzzy logic and expert systems for developing marketing strategies is proposed in this paper. Within this approach, the group Delphi method is employed to help groups of managers undertake SWOT analysis. Fuzzy logic is applied to fuzzify the results of SWOT analysis. Expert systems are utilised to formulate marketing strategies based upon the fuzzified strategic inputs. In addition, guidelines are also provided to help users link the hybrid approach with managerial judgement and intuition. The effectiveness of the hybrid approach has been validated with MBA and MA marketing students. It is concluded that the hybrid approach is more effective in terms of decision confidence, group consensus, helping to understand strategic factors, helping strategic thinking, and coupling analysis with judgement, etc.
Key quality factors in Web site design and use: an examination
Authors: Cox J. , Dale B.G.
Published: September 2002

The focus of the research described in this paper was to identify the key quality factors in Web site design and use. From the factors identified, a conceptual model has been developed to assess how a Web site can deliver what its users expect. The model is based on: ease of use, customer confidence, on‐line resources, and relationship services. These facts have been validated in an assessment of a range of Web sites. The model comprises a useful measurement tool which designers can use to suffice the quality of their Web sites.
An investigation of the total quality management survey based research published between 1989 and 2000
Authors: Sila Ismail , Ebrahimpour Maling
Published: September 2002

There has been a plethora of published research related to total quality management (TQM) in the last few decades. However, very few studies focused on cataloging critical factors of TQM. One of the objectives of this literature review was to investigate the state of TQM by examining and listing various TQM factors identified based on survey studies conducted in different countries and published in a variety of journals over the past decade. An examination of 76 survey studies that used an integrated approach to TQM showed that the TQM factors could be grouped under 25 categories. An analysis of the 347 survey based research articles published between 1989 and 2000 using these 25 factors as a framework revealed the most frequently covered TQM factors in the literature. Another goal of the paper was to analyse the objectives of these articles by year and type of journal they were published in to determine the trends in TQM survey based studies and recommend future direction for research. The analysis showed that the objectives of the 347 studies could be grouped under six categories.
Green roofs in temperate climates and in the hot‐humid tropics – far beyond the aesthetics
Authors: Köhler Manfred , Schmidt Marco , Wilhelm Grimme Friedrich , Laar Michael , Lúcia de Assunção Paiva Vera , Tavares Sergio
Published: September 2002

Green roofs are still often seen as a pure aesthetical element in architecture, as a spleen of some “greenies”. In fact green roofs already contribute, to some extent, to a better microclimate through evaporation, filtering of dust from the air and a decrease in temperatures at the rooftop. In cities like Berlin and Munich many green roofs have already been realised. Coupled with this microclimate improvement, is the thermal comfort improvement under such roofs by more mass, dry or wet substrate, and shading through the plants. Besides improving the microclimate and the indoor climate, the retention of rainwater is another important advantage. That means an important reduction of the rainwater input in the sewage system during rainfalls, cutting the peak load, avoiding an overload of the system, which might cause flooding and serious health problems. The risk of flooding in cities, which is increasing in many cities due to a ground sealed by buildings, asphalt and concrete, can be diminished. One recent example of the use of green roofs with this purpose is the Potsdamer Platz in the centre of Berlin, where 100 percent of the rainwater has to be evaporated or used for toilet flushing on the building site. Scientific knowledge on green roofs is still limited to temperate climates, due to a development which took place in central Europe. Since 2000 a scientific project in Rio de Janeiro is checking local parameters, like possible vegetation, which can be used and substrate composition. Parallel to this, four prototype roofs, three greened and one blank, are used to measure the retention rate of the rain water and the temperature on the underside of the roofs in order to analyse the possible improvement of the thermal comfort in buildings. This paper will describe the scientific results of Germany and discuss the practicability on a larger scale under tropical conditions.
Optimal orientation and automatic control of external shading devices in office buildings
Authors: Carbonari Antonio , Rossi Giancarlo , Romagnoni Piercarlo
Published: September 2002

Movable shading devices are often used to control solar radiation falling on large glazed surfaces in contemporary non‐residential buildings. The paper presents some studies on optimal orientation of building in relation to the type of adopted shading devices and their control logic, in case of adjustable ones. Optimal orientation is the one minimising total annual primary energy demand, including artificial lighting and climatisation, giving the same thermal and luminous comfort. A case study, a room of an office building, has been analysed by means of computer simulations. The external wall of the room is entirely glazed. The effects of three different shading elements configuration are compared. The simulations have been performed in three Italian climates (Venice, Rome, Trapani).
CHAOS IN A NEAR-INTEGRABLE HAMILTONIAN LATTICE
Authors: ROTHOS VASSILIOS M. , ANTONOPOULOS CHRIS , DROSSOS LAMBROS
Published: September 2002

We study the chaotic dynamics of a near-integrable Hamiltonian Ablowitz–Ladik lattice, which is N + 2-dimensional if N is even (N + 1, if N is odd) and possesses, for all N, a circle of unstable equilibria at ε = 0, whose homoclinic orbits are shown to persist for ε ≠ 0 on whiskered tori. The persistence of homoclinic orbits is established through Mel'nikov conditions, directly from the Hamiltonian structure of the equations. Numerical experiments which combine space portraits and Lyapunov exponents are performed for the perturbed Ablowitz–Ladik lattice and large scale chaotic behavior is observed in the vicinity of the circle of unstable equilibria in the ε = 0 case. We conjecture that this large scale chaos is due to the occurrence of saddle-center type fixed points in a perturbed 1 d.o.f Hamiltonian to which the original system can be reduced for all N. As ε > 0 increases, the transient character of this chaotic behavior becomes apparent as the positive Lyapunov exponents steadily increase and the orbits escape to infinity.