bluuebunny/crossref_metadata_2025 huggingface dataset:
The electronic Fermi surface e3 of aluminium under moderate compression
Authors: Bross Helmut
Published: December 2003

Both in LDA and in GGA the electronic structure of aluminium is evaluated by use of the MAPW selfconsistent scheme and with different exchange correlation functionals. Near and above the equilibrium lattice constant the electronic sheet of the Fermi surface, e3, is found to be quite similar to the model originally proposed by Ashcroft. However, even moderate compressions induce a drastic variation. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Combinatorial Oligocarbamate Collections: Synthesis by the Premix Method and Quality Control by HPLC‐MS
Authors: Warrass Ralf , Jung Günther , Wiesmüller Karl‐Heinz
Published: December 2003

The automated solid phase synthesis of 256 complex oligocarbamate collections by the premix method is described. The collections contain up to 1.9×106 compounds built up via synthons derived from 18 proteinogenic amino acids. The quality of the collections is investigated by comparing HPLC and electrospray ionization MS data of the products of the premix synthesis to those of a mixture of individually synthesized single compounds. The premix synthesis was found to yield compound mixtures in qualities sufficient for primary screening assays. For highly complex collections, where the determination of each single compound becomes impossible, the signal patterns of electrospray ionization mass spectrometry were compared to simulated mass distributions and good correlations between theoretical and measured data were observed. Therefore, highly diverse and complex oligocarbamate subcollections and individual compounds are conveniently accessible by optimized and reproducible protocols. The compounds are of particular value for lead finding due to their protease resistance and higher lipophilicity compared to peptides.
Prediction of Aqueous Solubility of Organic Compounds by Topological Descriptors
Authors: Yan Aixia , Gasteiger Johann
Published: December 2003

Two quantitative models for the prediction of aqueous solubility of 1293 organic compounds were generated by a Multilinear Regression (MLR) analysis, and a Backpropagation (BPG) neural network. The molecules were represented by 18 topological descriptors. The physicochemical relationship between solubility and the descriptors for different individual classes of monofunctional group compounds such as hydrocarbons, ethers, halocarbons, alcohols, aldehydes and ketones, acids, esters, and amines was investigated. The 1293 compounds were divided into a training set of 741 compounds and a test set of 552 compounds based on a Kohonen's self‐organizing neural network map. The models obtained show a good predictive power: for the test set, a correlation coefficient of 0.97 and a standard deviation of 0.52 were achieved by the backpropagation neural network approch.
Ortho Effects in Quantitative Structure Activity Relationships for Lipase Inhibition by Aryl Carbamates
Authors: Lin Gialih , Liu Yue‐Chen , Wu Yon‐Gi , Lee Yu‐Ru
Published: December 2003

Ortho‐substituted phenyl‐N‐butyl carbamates (1–11) are synthesized and evaluated for their inhibition effects on Pseudomonas species lipase. Carbamates 1–11 are characterized as pseudo‐substrate inhibitors of the enzyme. The logarithms of dissociation constant (Ki), carbamylation constant (k2), and bimolecular inhibition constant (ki) multiply linearly correlate with Hammett substituent constant (σ), Taft‐Kutter‐Hansch ortho steric constant (ES), and Swan‐Lupton field constant (F). For −logKi‐, logk2‐, and logki‐correlations, values of ϱ, δ, f, ρXR are 0.2, −0.06, −1.7, 0.8; 0.0, 0.0, 1.0, −0.07; and −1.8, 7, 0.6, 5; respectively. The enzyme inhibition mechanism is composed of four steps: 1) the first step which is protonation of carbamates 1–11, 2) the second step (Ki1) which involves in the proton 1,3‐shift of protonated carbamates 1–11 then the pseudo‐trans to cis conformational change, 3) the third step (Ki2) which is formation of a negative charged enzyme‐inhibitor tetrahedral intermediate, and 4) the fourth step (k2) which is the carbamylation step. The former three steps are likely composed of the Ki step. There is little ortho steric enhancement effect in the Ki step. From cross‐interaction correlations, distance between carbamate and phenyl substituents in transition state for the Ki step is relatively short due to a large ρXR value of 7. The k2 step is insensitive to ortho steric effect. The k2 step involves in departure of leaving group, substituted phenol in which is protonated from the proton 1,3‐shift but not from the active site histidine of the enzyme. From cross‐interaction correlations, the distance between carbamate and phenyl substituents in transition state for the k2 step is relatively long due to a small ρXR value of 0.6.
DFT Based Atomic Softness and Its Application in Site Selectivity
Authors: Singh P. P. , Pasha F. A. , Srivastava H. K.
Published: December 2003

Active site of a complex molecule and mechanism of chemical reaction has been studied with the help of atomic softness values derived from calculation based on Density functional theory. The quantum mechanical equation of Klopman has been solved with the help of AM1 calculation by using Win MOPAC7.21 software. On the basis of chemical potential equalization principle, and Koopmans theorem for frontier orbitals a formalism has been developed for the calculation of electron affinity of an atom in a molecule EA. The reliability of the EA values have been tested with electron density (obtained from AM1 calculation) and Fukui function values taken from literature.
Artemisinin Derivatives with Antimalarial Activity against Plasmodium falciparum Designed with the Aid of Quantum Chemical and Partial Least Squares Methods
Authors: Pinheiro José C. , Kiralj Rudolf , Ferreira Márcia M. C. , Romero Oscar A. S.
Published: December 2003

Artemisinin derivatives with antimalarial activity against Plasmodium falciparum resistant to mefloquine are designed with the aid of Quantum Chemical and Partial Least Squares Methods. The PLS model with three principal components explaining 89.55% of total variance, Q2=0.83 and R2=0.92 was obtained for 14/5 molecules in the training/external validation set. The most important descriptors for the design of the model were one level above the lowest unoccupied molecular orbital energy (LUMO+1), atomic charges in atoms C9 and C11 (Q9) and (Q11) respectively, the maximum number of hydrogen atoms that might make contact with heme (NH) and RDF030 m (a radial distribution function centered at 3.0 Å interatomic distance and weighted by atomic masses). From a set of ten proposed artemisinin derivatives, a new compound (26), was predicted with antimalarial activity higher than the compounds reported in literature. Molecular graphics and modeling supported the PLS results and revealed heme‐ligand and protein‐ligand stereoelectronic relationships as important for antimalarial activity. The most active 26 and 29 in the prediction set possess substituents at C9 able to extend to hemoglobin exterior, what determines the high activity of these compounds.
Effect of aluminium content on the coating structure and dross formation in the hot‐dip galvanizing process
Authors: Shawki Saher , Hamid Z. Abdel
Published: December 2003

Hot dipping of steel in aluminium–zinc baths of varying composition (5–90% Al) has been undertaken with the aim of elucidating the mechanism of coating formation. On the basis of these experiments, it has been possible to define a range of aluminium content over which there is a change from a normal galvanizing process to a typical aluminizing process. Alternatively, the coating structure and properties were markedly affected by the aluminium content of the dipping bath. The kinetics of such coatings acquires the character of the activation energy Ea. The effect of various silicon levels as an inhibitor to iron dissolution during hot dipping at different aluminium percentages was studied. The structure of dross formation in 55 wt.% Al–Zn was identified. The adverse effect of heavy accumulation of dross in the dipping pot on the coating structure also was shown. Copyright © 2003 John Wiley & Sons, Ltd.
Influence of substrate morphology on the cohesion and adhesion of thin PECVD oxide films on semi‐crystalline polymers
Authors: Rochat G. , Delachaux A. , Leterrier Y. , Månson J.‐A. E. , Fayet P.
Published: December 2003

The influence of the surface morphology of semi‐crystalline poly(ethylene terephthalate) (PET) and polyamide 12 (PA12) films on the adhesion and cohesion of thin oxide coatings is analysed, with attention paid to the role of spherulites and processing additives. The failure mechanisms of the coating are determined by means of fragmentation tests and the results are modelled using a constant interfacial strength approach with a Weibull‐type probability of fracture. Coating failure is shown to be initiated at defect sites such as pinholes and, in the case of PET, the presence of additives in the superficial layers of the polymer leads to a decrease of the crack onset strain by a factor of 20%. Large spherulitic structures found at the surface of PA12 films are shown to lead to preferential delamination at spherulites boundaries. For the two types of semi‐crystalline polymers, the interfacial shear strength is found to be comparable to the bulk shear strength of the polymer. Copyright © 2003 John Wiley & Sons, Ltd.
Parametric analysis of the extraction of depth profile information from ARXPS data obtained on a silicon wafer sample
Authors: Paynter R. W. , Nolet D.
Published: December 2003

In this study a silicon wafer was analysed by angle‐resolved x‐ray photoelectron spectroscopy and the data compared with a calculation based upon a simple model of the sample surface. The parameters in the mathematical model were varied in groups of three and the sum‐squared difference between the calculation and the experimental results was plotted as an error surface. Most of the error surfaces were found to exhibit a well‐constrained minimum, indicating an optimum set of values for the parameters in question, but important examples of co‐dependency were also noted. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of amount of substance for nanometre‐thin deposits: consistency between XPS, RBS and XRF quantification
Authors: Martin‐Concepción A. I. , Yubero F. , Espinos J. P. , Garcia‐Lopez J. , Tougaard S.
Published: December 2003

Quantification on the nanometre scale is a key task in quality control and for the development of new materials in nanotechnology. In this paper we have studied the consistency in the determination of the amount of substance found by XPS peak shape analysis, Rutherford backscattering spectroscopy (RBS) and x‐ray fluorescence spectrometry (XRF). To this end, ZnO was deposited by plasma‐enhanced chemical vapour deposition on the three substrates. Four different sets of samples were produced, with the amount of ZnO deposited in the range 1–10 nm. From XPS analysis it is found that ZnO grows in the form of islands on all three substrates. For each system, the analysis was done independently with two XPS peaks from the overlayer with widely different kinetic energy and one XPS peak from the substrate. The growth mechanism found from analysis of each of the three peaks was consistent and the total amount of determined ZnO material was identical to within 15%. The root‐mean‐square deviation from the XPS quantification of the relative AOS was 20% for XRF and 16% for RBS. Because the absolute amount of substance determined from analysis of the three XPS peaks for each sample was consistent, it is concluded that the energy dependence of the applied inelastic mean free paths (taken here from the empirical TPP‐2M formula) is correct. It was found that the absolute amounts of substance determined by RBS and XRF are consistently factors of 2.1 and 1.5 lower than the that determined by XPS peak shape analysis. It is suggested that the main reason for this large discrepancy is inaccuracy in the applied ‘effective’ inelastic electron mean free path. Copyright © 2003 John Wiley & Sons, Ltd.
Structure of Cooked Spaghetti of Durum and Bread Wheats
Authors: Heneen Waheeb K. , Brismar Kerstin
Published: December 2003

The structure of cooked spaghetti of durum and bread wheats was studied using low voltage scanning electron microscopy, and light microscopy applying different staining methods. Central, intermediate and external regions, and four zones along the external region of cooked spaghetti strands, were characterized in unprecedented detail. Changes in structure of starch granules from core to surface portrayed the successive stages in starch gelatinization, and possible starch retrogradation in the external region. Pronounced changes in shape of starch granules commenced in the intermediate region, while apparent internal changes dominated in the external region. Spaghetti of bread wheats differed from that of durum wheats by the larger size and higher extent of fusions and retrogradation of starch, and less amounts and continuity of intervening proteins. The significance of a high protein concentration for pasta production from bread wheats was emphasized. Furthermore, the relevance of a small size of the large starch granules was inferred.
Phase and Gelation Behavior of 2‐Hydroxy‐3‐(N, N‐dimethyl‐N‐dodecylammonium)propyloxy Starches
Authors: Jonhed Anna , Järnström Lars
Published: December 2003

Some starches containing quaternary dimethylalkylammonium groups exhibit an unique phase behavior. A solid phase or gel phase is formed upon cooling, i.e. they are temperature‐responsive polymers. The aim of this study was to investigate the phase and gelation behavior of hydrophobically modified quaternary ammonium starch ethers in aqueous solutions. The mechanisms behind the phase behavior and hydrophobic character were investigated by light scattering (turbidity) and rheological measurements. A relatively large increase in the complex viscosity at higher concentrations was observed when the solutions were cooled to room temperature. The phase angle decreased drastically at a certain critical temperature. The decrease in the phase angle depended on the concentration of starch in solution, higher concentrations showing the greatest decrease and lower concentrations showing no significant change. Turbidity measurements indicated that a solid‐like highly concentrated phase was precipitated. The starch with zero net charge showed a larger increase in turbidity than the starch with a positive net charge, which indicates that particular precipitation is favored by a zero net charge and that the formation of a gel network is favored by charged starch molecules.
Resistant Starch and Health — Himalaya 292, a Novel Barley Cultivar to Deliver Benefits to Consumers
Authors: Topping David L. , Morell Matthew K. , King Roger A. , Li Zhongyi , Bird Anthony R. , Noakes Manny
Published: December 2003

Dietary and lifestyle change is a recognised strategy for the management and prevention of socio‐economically important non‐infectious diseases. Dietary fibre is composed largely of non‐starch polysaccharides (NSP), and greater consumption of NSP‐rich foods relieves simple constipation very effectively. Starch (as resistant starch, RS) is also receiving attention for its potential role in promoting colonic function. Resistant starch is that fraction of starch which escapes human small intestinal digestion and enters the large bowel where (together with a variable fraction of NSP) it is fermented by the resident microflora. The resulting short chain fatty acids (SCFA) are taken up by the large bowel and metabolised. SCFA mediate many of the health benefits ascribed to NSP and RS. Starch consumption is low in affluent westernised countries, despite recommendations by health agencies. In Australia, foods enriched in RS as a high amylose maize starch have gained consumer acceptance. However, scope remains for additional products and ingredients and a company, Ascentia Pty Ltd, has been established to develop a novel barley cultivar (Hordeum vulgare var. himalaya 292) for this purpose. This cultivar has a specific gene alteration leading to a loss of starch synthetase lla activity resulting in a grain which is low in starch but disproportionately higher in amylose and also NSP. Animal and human studies have shown that Himalaya 292 is high in RS relative to existing products and has a low glycaemic index and the cultivar offers promise as a vehicle to deliver health benefits to consumers.
Pain and PTSD symptoms in female veterans⋆,⋆⋆
Authors: Asmundson Gordon J.G , Wright Kristi D , Stein Murray B
Published: December 2003

Background: There has been growing empirical examination of the co‐occurrence of pain and post‐traumatic stress disorder (PTSD) symptoms, and existing evidence suggests that the symptoms associated with each have a close association. To date, however, the association has only been examined within samples of mostly male participants.

Aim: In the present study, pain and PTSD symptoms were examined in a sample of 221 female veterans who utilised the VA Healthcare System between 1998 and 1999.

Method: Women who visited the clinic between 1998 and 1999 were mailed a self‐report questionnaire package designed to elicit information regarding general health (including pain experiences), military and trauma history, childhood abuse and neglect, and PTSD symptoms. Analyses were conducted to identify differences in pain experience between those women classified as having PTSD, subsyndromal PTSD, and no PTSD. Analyses were also conducted to determine the degree to which pain‐related (e.g., current pain, interference with activity) variables predicted PTSD symptom cluster scores.

Results: The three groups differed significantly on a number of pain‐related variables. Analyses suggested that pain‐related variables were significant predictors of PTSD symptom cluster scores.

Conclusions: These results indicate that the association between pain and PTSD symptoms, previously observed in primarily male samples, is generalisable to females. Clinical implications and possible mechanisms of association are discussed.
Electroconvulsive therapy in patients with depression and fibromyalgia
Authors: Huuhka Martti J , Haanpää Maija L , Leinonen Esa V.J
Published: December 2003

The effect of electroconvulsive therapy (ECT) on depression and other symptoms of fibromyalgia was studied in a prospective 3‐month trial in 13 patients with fibromyalgia and concomitant depression. All the patients met the DSM‐IV diagnostic criteria for Major Depressive Disorder and fulfilled the American College of Rheumatology diagnostic criteria for fibromyalgia. The Montgomery and Åsberg Depression Rating Scale (MADRS) and the clinical global impression scale (CGI) were used to assess the severity of depression and the clinical change of the patients. The fibromyalgia impact questionnaire (FIQ) was used to evaluate the severity of the fibromyalgia symptoms. The intensity of pain was evaluated using a 6‐point scale (0=no pain, 5=very severe pain), and tender point palpation. All assessments were performed at baseline and at follow‐up visits, which took place one week, one month and three months after ECT. There was a significant improvement in depression after ECT according to MADRS. Using CGI, six patients were much or very much improved, while four patients were minimally improved and three patients had no change. There was significant improvement in four out of ten FIQ item scores, “feel good”, “fatigue”, “anxiety” and “depression”. No significant change was found in the FIQ item scores “physical function”, “pain”, “stiffness” and “morning tiredness” or number of tender points and self‐reported pain. We conclude that ECT is a safe and effective treatment for depression in fibromyalgia patients, but has no effect on the pain or other physical symptoms of these patients.
Low back pain, disability and back pain myths in a community sample: prevalence and interrelationships
Authors: Goubert Liesbet , Crombez Geert , De Bourdeaudhuij Ilse
Published: December 2003

This study investigated the prevalence of back pain, disability, and, of most importance, the presence of misconceptions about low back pain (LBP), its diagnosis and treatment in a bicultural community sample (Belgium). Using the Graded Chronic Pain Scale [Pain 50 (1992) 133] persons were classified according to pain intensity and disability in five subgroups. The interrelationship between LBP beliefs and these five subgroups was also investigated. In our sample (n=1624) the 6‐month prevalence of low back pain was 41.8%. Only in 8.2% back pain was disabling. Misconceptions about back pain were widespread, even in the group reporting no back pain. The least misconceptions were found to exist in participants with mild LBP without disability. It is suggested that recovery from an episode of acute low back pain is an active process that involves a correction of beliefs about harm, about the need to restrict physical activities and about medical diagnosis and cure. Finally, it is argued that community actions may be useful to correct LBP myths in order to prevent the development of long‐term disability due to LBP.
Connexin 43 expression in glial cells of developing rhombomeres of Xenopus laevis
Authors: Katbamna Bharti , Jelaso Anna M. , Ide Charles F.
Published: December 2003

Connexin 43 is a gap junctional protein found predominantly in astrocytes. In the mammalian nervous system, it appears to play an organizational role during neural development. In the current study, conducted on the frog, Xenopus laevis, we found that connexin 43 occurs in glial cells during development of rhombomeres and that its expression is spatially and temporally regulated. We used neural (2G9) and cell proliferation (BrdU) markers to identify the overall organization of Xenopus rhombomeres and then tracked expression of connexin 43 and glial fibrillary acidic protein, an intermediate filament protein known to mark glia during rhombomeric development. 2G9 was expressed in rhombomeric centers (ventricular concavities) and outlying neuropil regions, whereas BrdU‐labeled cells marked boundary regions (ventricular convexities), as early as stage 35/36. These labeling patterns persisted through premetamorphic stages of hindbrain development. At stage 47, 2G9‐labeled profiles were highlighted by the presence of connexin 43, and at stage 49/50, connexin 43‐labeled profiles, i.e., rhombomeric centers and neuropil, as well as rhombomeric boundaries, not labeled by connexin 43, became immunoreactive to glial fibrillary acidic protein. Cells of rhombomeric center regions and their processes in the outlying neuropil co‐expressed glial fibrillary acidic protein and connexin 43 at a time that is characterized by the emergence of hindbrain auditory neural circuitry. Glial fibrillary acidic protein positive glial cells that appeared at rhombomeric boundaries never expressed connexin 43, but rather appeared to physically bisect ventricular convexities into adjacent rhombomeric regions. Thus, glial cells that express connexin 43 in developing rhombomeric centers may be similar to radial glia, assisting in formation of neural circuitry, while glial cells that do not express connexin 43, situated at rhombomeric boundaries, may be involved in demarcating adjacent rhombomeres.
Development of a polar morphology by identified embryonic motoneurons
Authors: Whitington Paul M. , Sink Helen
Published: December 2003

Motoneuron morphology arises through the coordinated growth of the motor axon and dendrites. In the Drosophila embryo the RP motoneurons have a contralaterally‐extended motor axon, ipsilateral dendrites that extend a short distance in the ipsilateral connective, and a tuft of short dendrites in the contralateral connective. In the present study mechanical and genetic manipulations were utilized to test if (i) the ipsilateral dendrites can develop an axon morphology, (ii) the presence of the contralateral motor axon suppresses the development of an axon‐like morphology by the ipsilateral dendrites and (iii) whether establishment of a contralateral motor axon can be genetically suppressed. It was found that an ipsilateral motor axon could develop—but only at the expense of the contralateral motor axon. Axotomy could overturn the normal polarity of the RP motoneurons in favor of the development of an ipsilateral motor axon, and this reversed morphology was also observed when the motor axon could not extend across the midline in the commissureless mutant. These findings show that the RP motoneurons have the plasticity for an alternative polarity, but that the extension of an ipsilateral axon is normally suppressed by the presence of the contralateral axon. The RP motoneurons now represent a genetically amenable in vivo system for analyzing the basis of polarity formation in neurons.
Mosquito repellent (pyrethroid‐based) induced dysfunction of blood–brain barrier permeability in developing brain
Authors: Sinha C. , Agrawal A.K. , Islam F. , Seth K. , Chaturvedi R.K. , Shukla S. , Seth P.K.
Published: December 2003

Pyrethroid‐based mosquito repellents (MR) are commonly used to protect humans against mosquito vector. New born babies and children are often exposed to pyrethroids for long periods by the use of liquid vaporizers. Occupational and experimental studies indicate that pyrethroids can cause clinical, biochemical and neurological changes, and that exposure to pyrethroids during organogenesis and early developmental period is especially harmful. The neurotoxicity caused by MR has aroused concern among public regarding their use.

In the present study, the effect of exposure of rat pups during early developmental stages to a pyrethroid‐based MR (allethrin, 3.6% w/v, 8 h per day through inhalation) on blood–brain barrier (BBB) permeability was investigated. Sodium fluororescein (SF) and Evan's blue (EB) were used as micromolecular and macromolecular tracers, respectively. Exposure during prenatal (gestation days 1–20), postnatal (PND1–30) and perinatal (gestation days 1–20+PND1–30) periods showed significant increase in the brain uptake index (BUI) of SF by 54% (P<0.01), 70% (P<0.001), 79% (P<0.001), respectively. This increase persisted (68%, P<0.01) even 1 week after withdrawal of exposure (as assessed on PND37). EB did not exhibit significant change in BBB permeability in any of the group. The results suggest that MR inhalation during early prenatal/postnatal/perinatal life may have adverse effects on infants leading to central nervous system (CNS) abnormalities, if a mechanism operates in humans similar to that in rat pups.
Relative risk aversion among the elderly
Authors: Bellante Don , Green Carole A.
Published: December 2003

This paper examines portfolio allocation behavior of the elderly, investigating whether their behavior conforms to Arrow's postulate of increasing relative risk aversion. Additionally, the effects on risk aversion of age, race, gender, education, health status, and the number of children are examined. The source of data is the AHEAD data set that is comprised of households with at least one member aged 70 or over. In the preferred specification, evidence supports a finding of modestly decreasing relative risk aversion and statistical significance for the personal characteristics examined. Implications are drawn for the likely security markets effects of an aging population.
Modelling the transmission dynamics of Echinococcus granulosus in dogs in rural Kazakhstan
Authors: TORGERSON P. R. , SHAIKENOV B. S. , RYSMUKHAMBETOVA A. T. , USSENBAYEV A. E. , ABDYBEKOVA A. M. , BURTISURNOV K. K.
Published: December 2003

Cystic echinococcosis, caused by Echinococcus granulosus, is an emerging disease in many parts of the world and, in particular, in eastern Europe and the former Soviet Union. This paper examines the abundance of infection of E. granulosus in the definitive host in southern Kazakhstan. Observed data are fitted to a mathematical model in order to decide if the parasite population is partly regulated by definitive host immunity and to define parameters in the model. Such data would be useful to develop simulation models for the control of this disease. Maximum likelihood techniques were used to define the parameters and their confidence limits in the model and the negative binomial distribution was used to define the error variance in the observed data. The results indicated that there were 2 distinct populations of dogs in rural Kazakhstan which had significantly different exposures to E. granulosus. Farm dogs, which are closely associated with livestock husbandry, particularly sheep rearing, had a relatively high mean abundance of 631 parasites per dog and a prevalence rate of approximately 23%. The best fit to the model indicated that there was significant herd immunity in the dog at this infection pressure. In contrast, village dogs which were more likely to be kept as pets had a much lower mean abundance of parasites of only 27 parasites per dog and a lower prevalence of 5·8%. With this village population of dogs, the best fit indicated negligible herd immunity.
Prevalence of Plasmodium falciparum pfcrt polymorphisms and in vitro chloroquine sensitivity in Senegal
Authors: DAILY J. P. , ROBERTS C. , THOMAS S. M. , NDIR O. , DIENG T. , MBOUP S. , WIRTH D. F.
Published: December 2003

Mutations in pfcrt K76T are associated with chloroquine resistance in Plasmodium falciparum. Previous studies of K76T mutations in Senegal reported the association of T76 with in vitro-resistant isolates, but this mutation was also prevalent in chloroquine-sensitive isolates. This suggests involvement of additional genetic loci in modulating chloroquine resistance. Additional pfcrt polymorphisms at codons A220S, Q271E, N326S and R371I have been found in chloroquine-resistant isolates. We wanted to test if sequential acquisition of mutations at these codons leads to in vitro chloroquine resistance. Stepwise accumulation of mutations was not detected, rather there was almost complete linkage between the pfcrt K76T mutation and polymorphisms in these codons. Therefore these additional polymorphisms do not enhance the correlation between pfcrt T76 and chloroquine resistance in Senegal. These data suggest that in vitro chloroquine resistance requires the genetic background of the pfcrt K76T mutation and additional mutations in genetic loci outside the pfcrt gene.
Local differentiation in Plasmodium falciparum drug resistance genes in Sudan
Authors: ABDEL-MUHSIN A. A. , MACKINNON M. J. , AWADALLA P. , ALI E. , SULEIMAN S. , AHMED S. , WALLIKER D. , BABIKER H. A.
Published: December 2003

Studies of population genetic structure of parasites can be used to infer which parasite genes are under selection. Here, the population structure of 4 genes associated with drug resistance of Plasmodium falciparum (the chloroquine resistance transporter, pfcrt, dihydrofolate reductase, dhfr, dihydropteroate synthase, dhps, and multi-drug resistance, pfmdr-1) were examined in parasite populations in 3 villages in eastern Sudan and in an urban area of Khartoum, the capital. In order to differentiate the effects of drug selection from neutral influences on population structure, parasites were also genotyped for 3 putatively neutral microsatellite loci (polyα, TA81 and pfg377), and for 2 antigenic loci that are either under balancing selection or neutral, merozoite surface protein 1 and 2, (MSP-1 and MSP-2). Cross-sectional surveys were carried out during the peak transmission (wet) season and in the ensuing dry season. No significant variation in frequencies of MSP-1 and MSP-2 alleles was seen among villages in the eastern region and between the villages and Khartoum, nor between the wet and dry season. However, the drug resistance genes, pfmdr-1, pfcrt and dhfr and to a lesser extent the microsatellite loci showed high FST values when comparing villages with Khartoum, indicating strong geographical differentiation at these loci. Moreover, variation in frequencies of the drug resistance genes, pfmdr-1, pfcrt and dhfr, was observed between the wet and dry season. These differences most probably reflect the variation in drug pressure between each region, and in drug usage between the wet and dry season in a given region.
Successful Reconstruction of Damaged Ocular Outer Surface in Humans Using Limbal and Conjuctival Stem Cell Culture Methods
Authors: Sangwan Virender S. , Vemuganti Geeta Kashyap , Singh Shashi , Balasubramanian D.
Published: December 2003

When the ocular outer surface is badly damaged, subsequent corneal transplantation fails due to the absence of basal cells that are needed to support the graft. With the realization that the limbus and the conjunctiva have adult stem cells that can be cultured, it has been possible for us to explant culture these on de-epithelized human amniotic membrane, and to graft the resulting viable and transparent epithelium to 125 needy human patients with success. Ultrastructural, histological, biochemical and immunological assays establish the identity of the cells and the tissue formed.
Solubilization of Adenylyl Cyclase from Human Myometrium in a αS-Coupled Form
Authors: Bajo Ana M. , Prieto Juan C. , Valenzuela Pedro , Martinez Pilar , Guijarro Luis G.
Published: December 2003

Adenylyl cyclase (AC) was extracted from human myometrium with either non-ionic (Lubrol-PX or Triton X-100) or zwitterionic (3-[3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, CHAPS) detergents. The soluble enzyme was stimulated by forskolin, a hydrophobic activator, in the presence of Mg2+ indicating that the catalytic subunit had not been damaged after solubilization. The enzyme was also activated by 5′-guanylyl imidodiphosphate (Gpp(NH)p) showing that the catalytic unit was not separated from stimulatory guanine nucleotide binding protein (Gs) during the extraction. Both activators showed different effects on the stimulatory efficacy and potency of AC activity solobulized with detergents. Gel filtration of Lubrol-PX and CHAPS extracts over a Sepharose CL-2B column partially resolved AC and its complexes. The chromatographic profile for Lubrolsolubilized AC presented a main peak of about 200 kDa whereas CHAPS-solubilized AC showed a dominant peak of about 1100 kDa. The heterodisperse peaks obtained revealed that the catalytic AC subunit was not separated from Gs proteins after gel filtration, and that AC could be associated with other cellular proteins. When Lubrol extract was submitted to anionic-exchange chromatography, the enzyme was purified about 7.5 fold (enzymatic activity of 48.1 pmol/min/mg of protein). The catalytic subunit was co-eluted with both AC-activating proteins Gαs large (52.2 kDa) and Gαs small (48.7 kDa). This is the first demonstration of the stable physical association of AC with both αs subunits of G proteins in human myometrium.
Mitotracker Green Is a P-Glycoprotein Substrate
Authors: Marques-Santos Luis F. , Oliveira José G. P. , Maia Raquel C. , Rumjanek Vivian M.
Published: December 2003

P-glycoprotein has a widespread expression on normal tissues. The protein has also been strongly associated with the multidrug resistance phenotype (MDR) on tumor cells. The employment of flow cytometry and confocal microscopy has contributed to the discovery and application of new particular fluorescent dyes. Nevertheless, several studies are being performed in different cellular types neglecting the expression activity of MDR proteins. Because many fluorochromes have been reported as P-glycoprotein substrates, an especial attention must be given to the properties of new dyes in the presence of MDR proteins. Flow cytometric analyzes of Mitotracker Green (MTG) fluorescence profile were performed in a human erythroleukemic cell line and its resistant counterpart. In this report we demonstrated that MTG, a probe used to evaluate the mitochondrial mass, is a P-glycoprotein substrate and its staining profile is dependent on the activity of this protein. In vitro studies on a human erythroleukemic cell line and its resistant counterpart revealed that MDR modulators (Cyclosporin A, Verapamil, and Trifluoperazine) alter the MTG fluorescence pattern on a resistant cell line. The findings suggest that attention should be given to the expression of P-glycoprotein when performing an evaluation of mitochondria properties with MTG.
A confirmatory factor analysis of scores on the teacher efficacy scale
Authors: Brouwers André , Tomic Welko , Stijnen Sjef
Published: December 2003

Validity studies on the Teacher Efficacy Scale provide us with neither clear evidence nor clear solutions to the factorial structure or the theoretical concepts underlying the scale’s items. This study tests different factor structures of the Teacher Efficacy Scale as found in the literature using confirmatory factor analysis on data from a sample of 540 practicing teachers. Four factorial models were formulated based on theoretical analysis and on the results of several validity studies of the Teacher Efficacy Scale. In accordance with Bandura’s (1997) self-efficacy theory, the results revealed that the fit of the four-factor oblique model was significantly better than that of the other factorial models. However, the fit of the four-factor model did not reach the recommended criterion of adequately fitting models. After eliminating three poorly loaded items, the model’s fit improved significantly but insufficiently to reach the fit criterion. It was concluded that the Teacher Efficacy Scale in its current state does not provide precise and valid information about teacher efficacy beliefs. Recommendations to improve the factorial validity of the Teacher Efficacy Scale are made.
Subjektives Familienbild bei Anorexia nervosa und Bulimia nervosa im Jugendalter: Eine kontrollierte Studie
Authors: Karwautz A. , Haidvogl M. , Wagner G. , Nobis G. , Wöber-Bingöl Ç. , Friedrich M. H.
Published: December 2003

Zusammenfassung: Fragestellung: Familienbeziehungen bei Essstörungen sind in den letzten Jahrzehnten intensiv beforscht worden. Subjektive Wahrnehmungen von familiären Beziehungen mittels des «Subjektiven Familienbildes», einem Instrument, das dazu entwickelt wurde, die unterschiedlichen Wahrnehmungen der Familienmitglieder bezüglich der entwicklungspsycho(patho)logisch relevanten Faktoren Autonomie und Verbundenheit in ihrer subjektiven Wertigkeit zu erfassen, wurden bei Adoleszenten mit Essstörungen allerdings nur in wenigen kleinen Gruppen untersucht. Methode: Unsere Studie hatte daher zum Ziel, (1) die subjektiven Wahrnehmungen von Familienbeziehungen in einer größeren klinischen Gruppe (n = 118) von weiblichen adoleszenten Patientinnen mit Magersucht beider Subtypen und Bulimie zu untersuchen, mit einer gesunden Kontrollgruppe (n = 96) zu vergleichen und (2) innerfamiliäre Unterschiede der Wahrnehmung des Familienbildes zu erfassen. Ergebnisse: Die Hauptergebnisse waren, dass Adoleszente mit Bulimia nervosa geringere Autonomie und geringere emotionale Verbundenheit in der Familie erlebten als alle anderen Gruppen. Die Adoleszenten mit Bulimie erlebten geringere Autonomie und emotionale Verbundenheit als ihre Väter dies wahrnahmen, und Adoleszente mit restriktiver Anorexie erlebten höhere emotionale Verbundenheit in den Familien als ihre Väter. Die Relevanz der Ergebnisse für das Verständnis der Familiendynamik wird diskutiert.
Reliabilität, Trainierbarkeit und Stabilität auditiv diskriminativer Leistungen bei zwei computergestützten Mess- und Trainingsverfahren
Authors: Bischof J. , Gratzka V. , Strehlow U. , Haffner J. , Parzer P. , Resch F.
Published: December 2003

Zusammenfassung: Fragestellung: Bei der vorliegenden Studie standen die Fragen nach der Trainierbarkeit auditiver Diskriminationsleistungen und ihr Zusammenhang mit der Lese- und Rechtschreibleistung im Mittelpunkt. Methodik: Computerverfahren zur Ton- und Phonemdiskrimination wurden entwickelt und in einer Vorstudie bei N = 63 Kindern der Zusammenhang zwischen den auditiven Diskriminationsleistungen und der Lese- und Rechtschreibleistung geprüft. In einer prospektiven Studie wurden anschließend 44 Kinder in drei nach Lese-Rechtschreibleistung parallelisierte Gruppen aufgeteilt: Eine Ton-, eine Phonemdiskriminations- und eine Kontrollgruppe. Nach der Eingangsdiagnostik erfolgte für die beiden ersten Gruppen ein vierwöchiges Diskriminationstraining, unmittelbar nach Trainingsende schloss sich für alle drei Gruppen die erste Nachtestphase an. Alle Kinder erhielten parallel ein spezifisches Lese- und Rechtschreibtraining innerhalb der Schule. Nach einem halben Jahr erfolgte eine weitere Testwiederholung. Ergebnisse: Beide Testverfahren erwiesen sich als hoch reliabel (rtt = .94 bzw. .95). Es fand sich ein signifikanter Zusammenhang zwischen der auditiven Diskriminationsleistung und der Lese- und Rechtschreibleistung. Die Ton- und Phonemdiskriminationsleistung waren signifikant trainierbar. Es zeigten sich im zeitlichen Verlauf sowohl spezifische Trainingseffekte als auch leichte trainingsunabhängige Entwicklungseffekte. Der Trainingseffekt zur Phonemdiskrimination, nicht aber zur Tondiskrimination erwies sich über einen Zeitraum von einem halben Jahr als ausreichend stabil. Schlussfolgerungen: Auditive Diskriminationsleistungen sind trainierbar. Es bleibt zu überprüfen, ob die nachgewiesenen Trainingseffekte auch zu einer verbesserten Lese- und Rechtschreibleistung führen können.
Intervention bei autistischen Störungen: Status quo, evidenzbasierte, fragliche und fragwürdige Techniken
Authors: Bölte S. , Poustka F.
Published: December 2003

Zusammenfassung: Fragestellung: Ziel dieser Arbeit ist es, umfassend und kritisch über Interventionsstrategien zu referieren, die bei der Therapie des Autismus zum Einsatz kommen. Methodik: Ansätze der Frühintervention, verhaltenstherapeutische Programme, «Social Skills»-Training, psychopharmakologische Therapie und alternative Ansätze werden vorgestellt und hinsichtlich ihrer empirischen Evidenz eingeschätzt. Ergebnisse: Autismus ist eine persistierende, phänotypisch heterogene Störung. Eine Heilung der Erkrankung ist heute nicht möglich. Allerdings können mittels individueller Förderung bemerkenswerte graduelle Verhaltensverbesserungen erreicht werden. Schlussfolgerungen: Zur realistischeren Bewertung der Wirksamkeit der einzelnen therapeutischen Methoden sind weitere Evaluationsstudien unabdingbar. Die bis heute durchgeführten Arbeiten entbehren u.a. häufig einer adäquaten Eingangsdiagnostik.
Verzicht auf eine EEG-Diagnostik vor Beginn und unter einer Therapie mit Methylphenidat: gefährlich oder gerechtfertigt?
Authors: Schmidt J. K. , Plück J. , von Gontard A.
Published: December 2003

Zusammenfassung: Einleitung: Die Empfehlungen zur Durchführung eines EEGs, vor bzw. unter einer Psychostimulanzien-Therapie, werden derzeit kontrovers diskutiert. In diesem Zusammenhang gibt es nur wenige Untersuchungen, die sich grundsätzlich mit der Frage beschäftigen, welche EEG-Veränderungen unter der Gabe von Psychostimulanzien bei Patienten ohne Epilepsie auftreten. Methodik: In der vorliegenden Arbeit wurden EEG-Befunde von 124 männlichen und weiblichen Kindern und Jugendlichen, die an einer hyperkinetischen Störung leiden, vor und unter einer Methylphenidat-Therapie retrospektiv ausgewertet. Das Ziel der Untersuchung war es, der Frage nachzugehen, welche Veränderungen sich unter einer Therapie mit Methylphenidat im EEG abbilden, um so praktische Hinweise für die Indikation von EEG-Ableitungen unter einer Methylphenidat-Therapie zu erhalten. Ergebnisse: Zusammenfassend zeigt sich, dass die Rate von hypersynchroner Aktivität unter Methylphenidat-Therapie nicht erhöht ist. Antikonvulsiv eingestellte Patienten blieben anfallsfrei und zeigten keine erhöhte Rate von hypersynchroner Aktivität (HSA). Schlussfolgerungen: Ob das Auftreten von epileptischen Anfällen von einer Methylphenidat- Medikation beeinflusst wird oder unabhängig davon ist, bleibt jedoch weiterhin offen. Aufgrund der erhobenen Daten kann auf eine EEG-Kontrolle unter einer Methylphenidat-Therapie verzichtet werden. Es sollte jedoch stets eine EEG-Diagnostik vor einer geplanten Methylphenidat-Therapie durchgeführt werden.
Komorbidität bei Zwangsstörungen im Kindes- und Jugendalter
Authors: Becker K. , Jennen-Steinmetz Ch. , Holtmann M. , El-Faddagh M. , Schmidt M. H.
Published: December 2003

Zusammenfassung: Fragestellung: Die Querschnittskomorbidität stationär behandelter kinder- und jugendpsychiatrischer Patienten mit Zwangsstörung soll untersucht werden. Methodik: Die Daten aller seit 1976 stationär behandelten Patienten mit einer Zwangsstörung (31 Mädchen; 46 Jungen) wurden in zwei Altersgruppen (< 15 Jahre; 15-19 Jahre) in Hinblick auf komorbide Diagnosen mit den epidemiologischen Daten der Kurpfalzstichprobe (90 Mädchen; 84 Jungen) verglichen. Darüber hinaus wurden in der Inanspruchnahmepopulation jene psychiatrischen Achse I-Diagnosen deskriptiv erfasst, bei denen Zwänge als diagnoseergänzende Symptome auftraten (n = 45). Ergebnisse: In den Altersgruppen der unter 15-jährigen Zwangspatienten zeigten sich bei den Jungen häufiger Ticstörungen. Zwangspatientinnen mit 15 bis 19 Jahren oder älter zeigten in Hinblick auf komorbide affektive Störungen eine Tendenz und hinsichtlich gleichzeitig bestehender Essstörungen ein signifikantes Ergebnis. Von den 27 Patientinnen, bei denen Zwänge als diagnoseergänzendes Symptom mit klinischer Interventionsdetermination diagnostiziert worden waren, hatten 18 eine Essstörung als Achse I-Diagnose. Schlussfolgerungen: Aufgrund unterschiedlicher Klassifikationskriterien, differierender Komorbiditäts-Definitionen, unterschiedlicher Altersgruppen und verschiedener Stichproben sind die Studien zu komorbiden Störungen bei Zwangskranken nur schwer miteinander vergleichbar. Das Auftreten komorbider Störungen kann leicht überschätzt werden, wenn die allgemeine Prävalenz psychischer Störungen in Hinblick auf Geschlecht und Alter nicht berücksichtigt wird.
Der Verlauf von Zwangsstörungen mit Beginn im Kindes- und Jugendalter - eine Literaturübersicht
Authors: Jans Th. , Hemminger U. , Wewetzer Ch.
Published: December 2003

Zusammenfassung: Fragestellung: Es soll ein aktueller Überblick über die Literatur zum mittelfristigen und langfristigen Verlauf der Zwangsstörung mit Beginn im Kindes- und Jugendalter gegeben werden. Methodik: Eine Literaturrecherche erfolgte mit der Literaturdatenbank MEDLINE, wobei einschlägige Publikationen ab dem Jahr 1983 erfasst wurden. Ältere Arbeiten wurden in der Übersichtsarbeit berücksichtigt, sofern deren Ergebnisse die Ergebnisse neuerer Arbeiten ergänzten. Ergebnis: Den Ergebnissen der vorliegenden Verlaufsstudien zufolge ist der Verlauf der juvenilen Zwangsstörung insgesamt als ungünstig zu bewerten. So wurden bei 30% bis 70% der Nachuntersuchten Zwangssymptome festgestellt bzw. eine Zwangsstörung diagnostiziert. Andere Klinische Störungen fanden sich bei 20% bis 96% der Patienten. Mindestens eine Persönlichkeitsstörung wiesen ein Drittel bis zwei Drittel der ehemaligen Patienten auf. Multikomorbiditäten waren insgesamt häufig. Beeinträchtigungen der psychosozialen Anpassung betrafen ganz besonders die Bereiche Partnerschaft und Sexualität. Die meisten hinsichtlich ihrer Prädiktionskraft untersuchten Variablen zeigten keinen Zusammenhang zur Zwangssymptomatik bei Katamnese. Schlussfolgerungen: Unterschiede in den Ergebnissen der Verlaufsstudien können durch unterschiedliche Studiendesigns zum Teil erklärt werden. Die Ergebnisse zum Verlauf der juvenilen Zwangsstörungen verweisen auf die hohe Stabilität der Erkrankung und die sie begleitende Komorbiditätsrate. Dies gilt es diagnostisch (Diagnostik auch zu Komorbidität, Familiendiagnostik) und therapeutisch (langfristige Begleitung, Behandlung auch der Komorbidität, Einbeziehung der Familie) zu beachten.