bluuebunny/crossref_metadata_2025 huggingface dataset:
Accurate mass measurement at enhanced mass‐resolution on a triple quadrupole mass‐spectrometer for the identification of a reaction impurity and collisionally‐induced fragment ions of cabergoline
Authors: Paul Gary , Winnik Witold , Hughes Nicola , Schweingruber Hans , Heller Rexford , Schoen Alan
Published: March 2003

In this study, accurate mass measurements were made by electrospray ionization (ESI) on a triple quadrupole mass spectrometer operating in enhanced mass‐resolution mode (peak width = 0.1 u FWMH), to give qualitative information relating to the pharmaceutical, cabergoline. Accurate mass determinations by ESI‐MS were performed on a protonated impurity formed during cabergoline storage. The accurate mass measurement resulted in only one proposed elemental composition for the impurity, using reasonable elemental limits and mass tolerance for the calculation. This information was sufficient to propose a structure for the impurity where ESI‐MS/MS proved consistent. The difference between the accurate mass measurement and the exact mass calculated for the proposed structure was 0.8 mmu, with a standard deviation of 0.7 mmu for replicate accurate mass determinations. Accurate mass determinations in ESI‐MS/MS provided information on cabergoline fragment ions formed through collisionally‐induced dissociation. Since the potential formation of isobaric ions exists for two major cabergoline fragment ions, accurate mass measurement allowed for the determination of the most probable fragment ion structures. The differences between the accurate mass measurements and exact masses calculated for the proposed fragment ions were 1.9 and 2.1 mmu, with standard deviations of 0.4 and 0.8 mmu, respectively, for replicate determinations. Copyright © 2003 John Wiley & Sons, Ltd.
Nanotube Membrane Sensors: Resistive Sensing and Ion Channel Mimetics
Authors: Wirtz M. , Martin C. R.
Published: March 2003

Nanotubule membranes are utilized for sensing applications and ion channel mimetics. The nanotubule membranes are composed of either gold or alumina. The gold nanotubule membranes are prepared via electroless deposition of Au on to the pore walls of a polycarbonate membrane, ie, the pores act as templates for the nanotubes. These membranes are a new class of molecular sieves and can be used to separate small molecules on the basis of molecular size. In addition, the use of these membranes in new approaches to electrochemical sensing is discussed. In this case, a current is forced through the nanotubes, and analyte molecules present in a contacting solution phase modulate the value of this transmembrane current. We further discuss synthetic micropore and nanotube membranes that mimic the function of a ligand‐gated ion channel, ie, these membranes can be switched from an ‘off’ state (no or low ion current through the membrane) to an ‘on’ state (higher ion current) in response to the presence of a chemical stimulus, eg, drug or surfactant. Ion channel mimics are based on both modified Au nanotube and microporous alumina membranes.

First published online: July 12, 2002.
Microstructural and physicochemical study of the buried Fe/AlGaAs(100) interface by transmission electron microscopy and x‐ray emission spectroscopy
Authors: Monteverde F. , Jonnard P. , Harel S. , Michel A. , Eymery J. P.
Published: March 2003

Among the magnetic metal/semiconductor contacts, the Fe/GaAs system has been widely studied owing to its potential applications in electronic devices. In contrast, there are not many studies concerning the Fe/AlxGa1−xAs contact, and in particular there are no reports concerning the changes induced in the interfacial zone by the presence of Al. In this work, thin polycrystalline iron films were deposited by ion beam sputtering at room temperature on a 300 nm thick Al0.25Ga0.75As layer grown by molecular beam epitaxy onto GaAs(001). X‐ray diffraction analysis showed that the iron films are polycrystalline, and indications of a (002) texture of the film were observed. The fine scale analysis of the interface was achieved by high‐resolution transmission electron microscopy (HRTEM) observations, the results of which are compared with the physicochemical information obtained from electron‐induced x‐ray emission spectroscopy, by analysing the Al 3p valence states at the Fe/AlxGa1−xAs interface. The HRTEM experiments on cross‐section samples indicate that the interfacial zone between iron and AlGaAs is limited to <1.5 nm in thickness. X‐ray emission spectroscopy showed the presence of Al atoms in an FeAl‐like environment at the interface, and the existence of wrong bonds and point defects. The estimated width of the perturbed interface (2.0 ± 0.5 nm) is in agreement with the HRTEM results. Copyright © 2003 John Wiley & Sons, Ltd.
Chemical maps of patterned samples by microline‐imaging laser‐induced plasma spectrometry
Authors: Cabalín L. M. , Mateo M. P. , Laserna J. J.
Published: March 2003

The potential of a microline‐imaging laser‐induced plasma spectrometry (LIPS) system for surface and depth analysis of heterogeneous solid samples in air at atmospheric pressure has been demonstrated. A pulsed Nd : YAG laser beam operating at 532 nm, with a homogeneous energy distribution (flat top laser), was used to generate a microline plasma on the sample surface. Subsequent light from the microline plasma was resolved spectrally and spatially and detected with an imaging spectrograph and an intensified charged‐coupled device detector. A patterned metal sample was chosen as the most appropriate for this study. Three‐dimensional chemical maps of Ni and Cu from the edge connectors of a printed circuit board have been obtained. With this experimental configuration, the lateral resolution (limited by crater width) was 42 µm and the spatial resolution along the spectrometer slit was 17.4 µm. The results illustrate the capability of microline imaging for fast mapping of large‐area samples and for depth profiling purposes. Copyright © 2003 John Wiley & Sons, Ltd.
Summary of ISO/TC 201 Standard XI. ISO 17974:2002—Surface chemical analysis—High‐resolution Auger electron spectrometers—Calibration of energy scales for elemental and chemical‐state analysis
Authors: Seah M. P.
Published: March 2003

This International Standard specifies a method for calibrating the kinetic energy scales of Auger electron spectrometers for elemental and chemical‐state analysis at surfaces. It is only applicable to instruments that incorporate an ion gun for sputter cleaning. This International Standard further specifies a method to establish a calibration schedule, to test for the kinetic energy scale linearity at one intermediate energy, to confirm the uncertainty of the scale calibration at one low and one high kinetic energy value, to correct for small drifts of that scale and to define the expanded uncertainty of the calibration of the kinetic energy scale for a confidence level of 95%. This uncertainty includes contributions for behaviours observed in interlaboratory studies but does not cover all of the defects that could occur. This International Standard is not applicable to instruments with kinetic energy scale errors that are significantly non‐linear with energy, to instruments operated at relative resolutions poorer than 0.2% in the constant ΔE/E mode or poorer than 1.5 eV in the constant ΔE mode, to instruments requiring tolerance limits of ±0.05 eV or less or to instruments equipped with an electron gun that cannot be operated in the energy range 5–10 keV. This standard does not provide a full calibration check, which would confirm the energy measured at each addressable point on the energy scale and should be performed according to the manufacturer's recommended procedures. Crown Copyright © 2003. Published by John Wiley & Sons, Ltd.
Degradation of plasticized PVC for biomedical disposable device under soft x‐ray irradiation
Authors: Manfredini M. , Atzei D. , Elsener B. , Marchetti A. , Rossi A.
Published: March 2003

Plasticized poly(vinyl chloride) (PVC) used for biomedical disposable devices was studied in the non‐sterilized state after different exposure times to soft x‐ray irradiation in a commercial photoelectron spectrometer (Al Kα, 15 kV/300 W; Mg Kα, 12 kV/240 W) by XPS surface analysis. The detailed spectra of C 1s, Cl 2p and O 1s have been recorded and processed. Irradiation with soft x‐rays induces a clear decrease of the total Cl 2p intensity, an increase of total C 1s intensity and a doubling of the O 1s intensity after 45 min of irradiation with Al Kα (300 W). Irradiation with Mg Kα (240 W) is slightly less damaging. These results can be interpreted with the classical PVC degradation model, e.g. bond cleavage with the formation of HCl gas, although the Cl 2p high‐resolution spectra reveal the formation of an additional side‐product, probably CaCl2. For further studies of plasticized PVC using XPS surface analysis it can be concluded that a complete analysis of a polymer sample should not take >10 min of x‐ray exposure in order to avoid notable polymer degradation. Copyright © 2003 John Wiley & Sons, Ltd.
Population pharmacokinetics/pharmacodynamics relationships of an anticancer drug
Authors: Ané Cécile , Concordet Didier
Published: March 2003

This paper proposes a method for studying the toxicity of an anticancer drug with a delayed effect. The goal is to predict a dosage regimen with controlled toxicity. To this end, a semi‐physiological model is used. A limit of toxicity is demonstrated, which is intrinsic to the model. It reduces the effect of high drug concentrations. This limit explains the mixed behaviour of the drug: time‐dependence and concentration‐dependence, according to the dose actually administered. A population analysis is performed to estimate the parameters of the model, and to predict a safe dosage regimen. Copyright © 2003 John Wiley & Sons, Ltd.
Multilevel webs stretched across time: retroactive and proactive inter‐influences
Authors: Hardy Christine
Published: March 2003

Semantic Fields Theory (SFT) poses that the mind works through semantic network dynamics (i.e. knowledge acquisition) and specific semantic parameters. Consequently, the mind is intrinsically non‐dependent on space‐time and yet its dynamics crisscross it. Personal and collective anticipations and projections create a Multilevel Web (semantic forces coupled with their environment) which has the specificity of being conjointly tied to the present and future time of implementation. The resulting system, or Sygma‐Web, instantiates proactive and retroactive properties, such as informing both the project's present context and its future context, and the trajectory in between. Using as an example the development of a new product, I argue that classical causality accounts for only a local effect of the future product (once released) on the future market. By contrast, the Sygma‐Web formalization posits that collective expectations about a future shift in the market and consumer behaviours are specifically the force that changes the market in the direction of the expectations. Copyright © 2003 John Wiley & Sons, Ltd.
Economy of communion: systemic factors in the rise of a new entrepreneurship
Authors: Linard Keith T.
Published: March 2003

The Economy of Communion is an experience of social economy sprung from the praxis of the Focolare Movement, an ecumenical and inter‐religious organization with roots in the Catholic Church. This radical social phenomenon is played out in intersecting local and global networks. Businesses operating within the paradigm form communications and ‘thought networks’ spanning the globe, but function typically within local markets. Within a decade this ideal has spread to 100 countries, attracted some 800 firms, generated almost 100 academic theses, and been accorded significant international recognition through UNESCO and the Council of Europe and through the award of various honorary doctorates by prestigious universities. This paper examines the systemic philosophical, cultural and organizational factors associated with its dissemination. Copyright © 2003 John Wiley & Sons, Ltd.
Nitric oxide modulates striatal neuronal activity via soluble guanylyl cyclase: An in vivo microiontophoretic study in rats
Authors: Di Giovanni Giuseppe , Ferraro Giuseppe , Sardo Pierangelo , Galati Salvatore , Esposito Ennio , La Grutta Vittorio
Published: March 2003

It is now well established that nitric oxide (NO) acts as a neuromodulator in the central nervous system. To assess the role of NO in modulating striatal activity, single‐unit recording was combined with iontophoresis to study presumed spiny projection neurons in urethane‐anesthetized male rats. Striatal neurons recorded were essentially quiescent and were therefore activated to fire by the iontophoretic administration of glutamate, pulsed in cycles of 30 sec on and 40 sec off. In this study, iontophoresis of 3‐morpholinosydnonimine hydrochloride (SIN 1), a nitric oxide donor, produced reproducible, current‐dependent inhibition of glutamate‐induced excitation in 12 of 15 striatal neurons, reaching its maximal inhibitory effect (76.2 ± 5.6% below baseline) during the application of a 100 nA current. Conversely, microiontophoretic application of N‐ω‐nitro‐L‐arginine methyl ester (L‐NAME), an inhibitor of nitric oxide synthase, produced clear and reproducible excitation of glutamate evoked firing in 7 of 10 cells (51.4 ± 2.3%, at 100 nA). To evaluate the involvement of cyclic guanosine monophosphate (cGMP) in the electrophysiological effects produced by the NO donor, the effects of methylene blue, an inhibitor of guanylyl cyclase, on the responses of nine neurons to SIN 1 were tested. In six of nine neurons the effect of SIN 1 was significantly reduced during continuous iontophoretic administration (50 nA) of methylene blue. Taken together, these data show that NO modulates the striatal network and that inhibitory control of the output neurons is involved in this effect. These results also suggest that the effects of nitric oxide on striatal neurons are partially mediated via cGMP. Synapse 48:100–107, 2003. © 2003 Wiley‐Liss, Inc.
Oral toxicity of the cyanobacterial toxin cylindrospermopsin in male Swiss albino mice: Determination of no observed adverse effect level for deriving a drinking water guideline value
Authors: Humpage A. R. , Falconer I. R.
Published: March 2003

The cyanobacterial toxin cylindrospermopsin (CYN) is a frequent contaminant of freshwaters throughout the world, including those that are sources of drinking water. The first cases of human poisoning attributed to this toxin occurred from a treated drinking water supply in Queensland, Australia, in 1979. The toxin causes extensive damage to the liver, kidneys, spleen, heart, and other organs. It is known to be a potent protein synthesis inhibitor, but there is mounting evidence for genotoxicity and that it metabolizes to even more toxic forms. As part of a risk assessment process leading to a guideline for a safe drinking water level for this toxin, we performed a series of experiments to determine a no‐observed‐adverse‐effect level (NOAEL) for this toxin. In the first trial male mice were exposed to CYN‐containing cyanobacterial extract in their drinking water (0–657 μg CYN kg−1 day−1) for 10 weeks. In the second trial mice received purified CYN by daily gavage (0–240 μg CYN kg−1 day−1) for 11 weeks. Body and organ weights were recorded; urine, serum, and hematology analyses were performed; and histopathological examination of tissues was carried out. Body weights were significantly increased at low doses (30 and 60 μg kg−1 day−1) and decreased at high doses (432 and 657 μg kg−1 day−1). Liver and kidney weights were significantly increased at doses of 240 μg kg−1 day−1 and 60 μg kg−1 day−1, respectively. Serum bilirubin levels were significantly increased and bile acids significantly decreased at doses of 216 μg kg day−1 and greater. Urine total protein was significantly decreased at doses above 60 μg kg−1 day−1. The kidney appeared to be the more sensitive organ to this toxin. If it is assumed that increased organ weights and changes in functional capacity are responses to an underlying toxic effect, then the NOAEL based on this data is 30 μg kg−1 day−1, which, with standard calculations and uncertainty factors, provides a proposed guideline safety value of 1 μg/L in drinking water. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 94–103, 2003.
Influence of body size and gender on valve movement responses of a freshwater bivalve to uranium
Authors: Markich Scott J.
Published: March 2003

Body size, age, and gender (male or female) are important variables influencing many aspects of the ecology, physiology, and survival of animals. However, no data are available on the influence of these variables on bivalves exposed to sublethal metal concentrations. This study tested whether the valve movement responses (measured in terms of the duration or frequency of valve opening) of the Australian tropical freshwater unionoid bivalve, Velesunio angasi, exposed to sublethal uranium (U) concentrations in a standard synthetic water (pH, 6.0; hardness and alkalinity, 4 mg/L as CaCO3) were influenced by body size (shell length, shell breadth, or dry tissue weight), age, and/or gender. The valve movement responses of V. angasi to U were independent of gender; the sensitivity of males to U was not significantly (p > 0.05) different from that of females. In contrast, the valve movement responses of V. angasi to U were size‐ and age‐dependent; smaller and younger individuals (median shell length = 36.8 mm; median age = 0.7 years) were 22% more sensitive (p ≤ 0.05) than larger and older individuals (median shell length = 61.3 mm; median age = 14 years). By correcting for differences in body size, age, and/or gender among individuals, using multiple linear regression analyses, the mean variability in valve movement responses was reduced by 81%. Consequently, errors (95% confidence limits) associated with valve movement response (EC50) values were substantially reduced (75%). Hence, the ability to demonstrate statistically significant (p ≤ 0.05) differences in valve movement responses between U exposure concentrations was enhanced. This, in turn, may permit better estimates of the risk of the effects of U exposures to bivalve populations. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 126–136, 2003
Successful outcome in a fetus with an extremely low heart rate due to isolated complete congenital heart block
Authors: Vesel S. , Završnik T. , Podnar T.
Published: March 2003

Isolated complete congenital heart block (CCHB) in a fetus is usually associated with the presence of autoantibodies to SSA (Ro) and SSB (La) antigens in the maternal circulation. Although the prognosis for the majority of fetuses is good, it is less favorable in fetuses with a ventricular rate < 55 bpm in early pregnancy or with a decrease in the ventricular rate by ≥ 5 bpm during pregnancy. It is not known if the same prognostic criteria apply for the occasional fetus with isolated non‐autoimmune CCHB. We report a case of a single fetus with an isolated non‐autoimmune CCHB with an extremely low ventricular rate (37 bpm) in which the outcome was favorable. Dilated cardiomyopathy is a rare complication in patients with isolated CCHB, despite early institution of cardiac pacing, and is usually recognized after several months of relative well‐being. It is assumed that in the majority of patients it represents a sequel to in utero autoimmune or postnatal reactivation myocarditis. However, the possibility of a tachycardia‐induced cardiomyopathy caused by an excessively high pacing rate should also be taken into consideration, as was clearly demonstrated in our patient. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Methylcellulose gel is a superior contrast agent for ultrasound examination of the cervix in obstetric patients
Authors: O'Brien J. M. , Houseman B. A. , Allen A. A. , Barton J. R.
Published: March 2003

Objective

To determine the superior contrast agent for cervical sonography: water‐soluble methylcellulose gel vs. normal saline.

Methods

Women with an indication for cervical sonography underwent placement of 10 mL water‐soluble methylcellulose gel or normal saline. Assessment of cervical dimensions and contour was performed via transperineal sonography prior to and after contrast placement.

Results

Twenty‐five patients with similar demographic characteristics and indications for ultrasonography were enrolled into each group. Administration of contrast improved the ability to visualize the external os or vaginal fornices in 18 women in the gel group vs. six in the saline group (P = 0.002). In the gel group, 17 patients had easier identification of the external os and visualization of the fornices was enhanced in 13 patients. The assessment of cervical length prior to and after contrast administration was not statistically different with the use of either of these agents.

Conclusion

Intravaginal soluble gel is superior to normal saline as a cervical contrast agent. Intravaginal contrast may allow for easier identification of cervical anatomy during ultrasonographic examination in selected patients. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Predictors of success in methotrexate treatment of women with unruptured tubal pregnancies
Authors: Nazac A. , Gervaise A. , Bouyer J. , De Tayrac R. , Capella‐Allouc S. , Fernandez H.
Published: March 2003

Objective

The use of methotrexate (MTX) for the treatment of tubal ectopic pregnancy (EP) has become common practice, although the factors associated with a favorable outcome are not totally clear. The aim of this study was to investigate the predictors of successful MTX treatment.

Methods

One hundred and thirty‐seven women with unruptured tubal EP in whom the hematosalpinx could be directly visualized by pelvic ultrasound were studied. Women who met the inclusion criteria were treated with MTX either: 50 mg/m2 intramuscularly (n = 70) or with 1 mg/kg injected directly into the hematosalpinx under sonographic guidance (n = 67). The associations between the outcome of the treatment and different factors studied (human chorionic gonadotropin (hCG) level, progesterone level, hematosalpinx diameter, hemoperitoneum volume and mode of MTX administration) were analyzed.

Results

The overall success rate, defined by a post‐treatment normal hCG level (< 10 mIU/mL), was 79.6%. The initial hCG level and the route of administration of MTX appeared to be two independent factors that predicted success. Multivariate analysis demonstrated that the success rate was significantly better when MTX was administered locally: the odds ratio (OR) was 9.7 (95% CI, 3.1–30), and was significantly poorer when the hCG level was ≥ 1000 mIU/mL (P < 0.002): the OR was 0.10 (95% CI, 0.07–0.49).

Conclusion

Among selected women with tubal EPs, the route of administration of MTX and the initial level of serum hCG are the most important factors associated with the success of medical treatment. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Modelling and rendering of snowy natural scenery using multi‐mapping techniques
Authors: Yanyun Chen , Sun Hanqiu , Hui Lin , Wu Enhua
Published: March 2003

Realistic image synthesis of highly complex, natural scenes has been a challenging topic in computer graphics over the years. Generation of snowy scenery could be even more difficult due to the difficulty of using common modelling primitives such as polygons and curved surfaces to express the snow‐like shapes. In this paper, we propose a hybrid multi‐mapping method to tackle the snowy scenery problem, in which a displacement map is utilized to model snowy blocks on near objects based on proximate polygons, and a volumetric texture map is combined to handle distant objects such as bushes and trees. Our experimental results showed that the hybrid method is viable in producing realistic snowy scenery with comprehensive complex environments, and in a favourable requirement of storage usage and rendering computation. Copyright © 2003 John Wiley & Sons, Ltd.
Simulating the aurora
Authors: Baranoski Gladimir V. G. , Rokne Jon G. , Shirley Peter , Trondsen Trond S. , Bastos Rui
Published: March 2003

We present the first computer graphics algorithm designed to simulate the aurora, a natural phenomenon of great visual beauty and considerable scientific interest. The algorithm is based on the current understanding of the physical origin of this natural display. The aurorae are mainly caused by high‐energy electrons originating in the sun and entering the earth's atmosphere in narrow regions centered on the magnetic poles. These electrons collide with atmospheric atoms, which are excited to higher energy levels. The excited atoms emit rapidly varying visible light in a curtain‐like volume as they return to lower energy levels, thereby creating the aurora. By simulating these light emissions along with the spatial and temporal distribution of the entering electrons, we are able to render the major visual aspects of auroral displays. The applicability of this auroral model for rendering and scientific purposes is illustrated through comparisons of synthetic images with photographs of real auroral displays. Copyright © 2003 John Wiley & Sons, Ltd.
Offshore Wind Energy in Europe— A Review of the State‐of‐the‐Art
Authors: Henderson Andrew R. , Morgan Colin , Smith Bernie , Sørensen Hans C. , Barthelmie Rebecca J. , Boesmans Bart
Published: March 2003

After several decades of theoretical developments, desk studies, experimental wind turbines and prototype wind farms, the first large‐scale commercial developments of offshore wind farms are now being built. To support and accelerate this development, the European Commission funded a project, ‘Concerted Action on Offshore Wind Energy in Europe’ (CA‐OWEE), which aimed to gather, evaluate, synthesize and distribute knowledge on all aspects of offshore wind energy, including offshore technology, electrical integration, economics, environmental impacts and political aspects. The partners are from a wide range of fields and include developers, utilities, consultants, research institutes and universities. This article reports on the final conclusions of this project, with the complete report being available online at http://www.offshorewindenergy.org. Copyright © 2003 John Wiley & Sons, Ltd.
Synthese und thermische Eigenschaften von molekularen Clusterverbindungen zusammengesetzt aus Elementen der Gruppen 11‐13‐16
Authors: Olkowska‐Oetzel Jolanta , Fenske Dieter , Scheer Petra , Eichhöfer Andreas
Published: March 2003

CuX (X = Cl, CH3COO) bzw. AgOC(O)C6H5 und GaCl3 reagieren in THF mit S(SiMe3)2 bzw. Se(SiMe3)2 in Anwesenheit von PPh3 zu [Cu6Ga8Cl4S13(PPh3)6] (1), [Cu6Ga8Cl4Se13(PPh3)6] (2), [Ag6Ga8Cl4S13(PPh3)6] (4) und [Ag6Ga8Cl4Se13(PPh3)6] (5). Verwendet man anstelle von PPh3 das Phosphan PnPr2Ph, so läßt sich nach Überschichten mit n‐Hexan die Verbindung [Cu6Ga8Cl4Se13(PnPr2Ph)12] (3a, 3b) kristallisieren. Durch Umsetzung von CuCl, GaCl3 und PnPr3 mit Se(SiMe3)2 in THF erhält man den ionischen Cluster (HPnPr3)2[Cu2Ga4Cl4Se6(PnPr3)4] (6). Die Strukturen der Verbindungen 1—6 konnten durch Einkristall‐Röntgenstrukturanalyse aufgeklärt werden. TGA‐MS‐Messungen und Pulverdiffraktogramme der Rückstände zeigen die potentielle Verwendbarkeit der Cluster als Prekursormaterialien zur Darstellung der entsprechenden ternären Festkörperverbindungen.
Die Undecaarsenide A3As11 (A = Rb, Cs) — Synthesen und Kristallstrukturen
Authors: Emmerling Franziska , Röhr Caroline
Published: March 2003

Rb3As11 und Cs3As11 wurden aus den Elementen synthetisiert und die Kristallstrukturen der geordneten Raumtemperaturmodifikationen auf der Basis von Röntgen‐Einkristalldaten bestimmt. In den Zintl‐Phasen bilden die As‐Atome chirale Ufosan‐Anionen As mit As‐As‐Abständen im Bereich zwischen 238 und 248 pm. Rb3As11 kristallisiert wie K3As11 im Na3P11‐Strukturtyp (orthorhombisch, Raumgruppe Pbcn, a = 1108.2(2), b = 1533.5(3), c = 1060.1(2) pm, Z = 4), die Cs‐Verbindung (monoklin, Raumgruppe C2/c, a = 1324.5(7), b = 1524.5(9), c = 1937.2(11) pm, β = 95.29(1)°, Z = 8) kristallisiert dagegen in einem neuen Strukturtyp. Die kristallographischen Bezüge zwischen den beiden Strukturtypen und den Anionenpackungen der plastisch kristallinen Hochtemperaturformen werden diskutiert.
Solvothermal Synthesis and Characterization of the New Iron Thioantimonates(III) [Fe(C6H18N4)]FeSbS4 and [Fe(C4H13N3)2]Fe2Sb4S10 Containing FeII and FeIII and Protein‐Analogous [2FeIII‐2S]2+ Clusters
Authors: Kiebach Ragnar , Bensch Wolfgang , Hoffmann Rolf‐Dieter , Pöttgen Rainer
Published: March 2003

The two new compounds [Fe(tren)]FeSbS4 (1) (tren = tris(2‐aminoethyl)amine) and [Fe(dien)2]Fe2Sb4S10 (2) (dien = diethylendiamine) were prepared under solvothermal conditions and represent the first thioantimonates(III) with iron cations integrated into the anionic network. In both compounds Fe3+ is part of a [2FeIII‐2S] cluster which is often found in ferredoxines. In addition, Fe2+ ions are present which are surrounded by the organic ligands. In (1) the Fe2+ ion is also part of the thioantimonate(III) network whereas in (2) the Fe2+ ion is isolated. In both compounds the primary SbS3 units are interconnected into one‐dimensional chains. The mixed‐valent character of [Fe(tren)]FeSbS4 was unambiguously determined with Mössbauer spectroscopy. Both compounds exhibit paramagnetic behaviour and for (1) a deviation from linearity is observed due to a strong zero‐field splitting. Both compounds decompose in one single step.
Ein neuer Aluminium/Nickel/Oxo‐Cluster: [Ni(acac)OAl(OtBu)2]4
Authors: Veith Michael , Valtchev Kroum , Huch Volker
Published: March 2003

Bis(tert‐butoxi)alan (tBu‐O)2AlH reagiert mit Nickeldiacetylacetonat bei höheren Temperaturen zum neuartigen Nickel‐Aluminium‐Sauerstoff‐Cluster [Ni(acac)OAl(OtBu)2]4; neben anderen Produkten wird auch Aluminiumtriacetylacetonat Al(acac)3 gebildet. Der Metall‐Sauerstoff‐Cluster lässt sich durch Kristallisation isolieren und kann über Röntgenstrukturanalyse charakterisiert werden. Das Molekül [Ni(acac)OAl(OtBu)2]4 enthält im Zentrum einen achtgliedrigen Al4O4‐Ring, an den acht kantenverknüpfte NiO2Al‐Ringe über gemeinsame O‐Al‐O‐Einheiten gebunden sind. Die Punktsymmetrie des Metall‐Sauerstoff‐Clusters beträgt nahezu S4. Während die Aluminiumatome verzerrt tetraedrisch von Sauerstoffatomen umgeben sind (mittlerer Abstände Al‐O zwischen 1, 730(6) und 1, 789(6) Å)), befinden sich die Nickelatome in verzerrt quadratisch pyramidalen Sauerstoff‐Koordinationssphären (Ni‐Oaxial = 1, 938(6) Å, Ni‐Obasal = 2, 056(9)Å). Die Nickelatome sind in einem Highspin‐d8‐Zustand (μeff = 3, 32 B.M.).
Adherence of Plasmodium falciparum-Infected Erythrocytes to Chondroitin 4-Sulfate
Authors: Gowda D. Channe , Ockenhouse Christian F.
Published: March 2003

Adherence of Plasmodium falciparum-infected erythrocytes (PRBCs) to the microvascular endothelium of specific organs and consequent sequestration is believed to be responsible for the development of malaria pathology. A number of studies have shown that cell adhesion molecules expressed on the surface of endothelial cells mediate the adherence. Recent studies indicate that a subpopulation of PRBCs adhere to chondroitin 4-sulfate (C4S). This adhesion can be effectively inhibited by C4S oligosaccharides. In pregnant women, the placenta specifically selects C4S-adherent PRBCs, and thus these phenotypes multiply and sequester in the intervillous spaces. Over successive pregnancies, women develop a protective humoral response to the C4S-adhesion phenotype. Disruption of C4S-mediated PRBCs adhesion using either a C4S oligosaccharide mimetic or an antiC4S-adhesion vaccine can be an efficient strategy for the treatment of malaria caused by C4S-adherent P. falciparum.
Lectin-Carbohydrate Interactions: Fine Specificity Difference Between Two Mannose-Binding Proteins
Authors: Lee Reiko T. , Shinohara Yasuro , Hasegawa Yukio , Lee Yuan C.
Published: March 2003

Two types of rat mannose-binding proteins (MBPs), MBP-A (serum type) and MBP-C (liver type), have similar binding specificity for monosaccharide and similar binding site construct according to the X-ray structure, but exhibit different affinity toward natural oligosaccharides and glycoproteins. To understand the basis for this phenomenon, we used cloned fragment of MBP-A and -C (entire carbohydrate-recognition domain and a short connecting piece) that exists as stable trimers in various binding studies. Binding of a number of mannose-containing di- and tri-saccharides and high-mannose type oligosaccharides indicated that MBP-C has an extended binding area of weak interaction with the second and the third mannose residues, whereas MBP-A recognizes just a single mannose residue. In addition, MBP-C has a weak secondary binding site some 25 Å away from the primary site. These findings explain the higher affinity of MBP-C for natural high-mannose type oligosaccharides as compared to MBP-A. A huge affinity differential manifested by natural glycoproteins (e.g., inhibitory potency of thyroglobulin is ∼200 fold higher for MBP-C than for MBP-A in a solid-phase assay) may be due to steric hindrance experienced by MBP-A in the competition assay, and suggests different arrangement of subunit in the MBP trimers.
How the European Union Keeps the Social Welfare Debate on Track: A Lawyer's View of the EU Instruments Aimed at Combating Social Exclusion
Authors: Schoukens Paul
Published: March 2003

The article provides a legal perspective on the current debate on combating social exclusion at the EU level. In the first place, it attempts to provide a legal definition of the concept of social exclusion. It then investigates whether there have been any dramatic changes in the competencies of the EU to act in the field of social exclusion since the Treaty of Amsterdam came into force. The open method of coordination, the Treaty of Nice and the EU Charter of Fundamental Rights are all assessed regarding their potential for combating social exclusion.
Role of an ABC Importer in Mycobacterial Drug Resistance
Authors: Chakraborti Pradip K. , Bhatt Kamlesh , Banerjee Sanjiban K. , Misra Parimal
Published: March 2003

Phosphate specific transporter (Pst) in bacteria is involved in phosphate transport. Pst is a multisubunit system which belongs to the ABC family of transporters. The import function of this transporter is known to be operative at media phosphate concentrations below the millimolar range. However, we found amplification of this transporter in a laboratory generated ciprofloxacin resistant Mycobacterium smegmatis colony (CIPr) which was grown in a condition when phosphate scavenging function of this operon was inoperative. Our results therefore argue the role of this ABC importer in conferring high level of fluoroquinolone resistance in CIPr.
MADS‐Box Genes Controlling Flower Development in Rice
Authors: Fornara F. , Marziani G. , Mizzi L. , Kater M. , Colombo L.
Published: March 2003

Abstract:The separation between monocot and dicot plants occurred about 120 ‐ 180 million years ago and since then major morphological changes have led to the striking differences that can be observed today. To understand whether, despite these differences, the processes controlling flower development are fundamentally comparable in dicot and monocot species, it is necessary to perform comparative studies. However, until recently flower development has been studied mainly in dicot plant species. Genetic and molecular analyses of two dicot model species,Arabidopsis thalianaandAntirrhinum majus,led to the formulation of the ABC model of flower development that describes how the combined activities of three classes of genes are required to drive flower organ development. This model has recently been extended by the inclusion of two other gene classes, namely D and E, which are involved in ovule development, and petal, stamen and carpel development, respectively. Most of the A, B, C, D and E genes identified so far have been shown to encode MADS‐box transcription factors. In rice a number of regulatory genes belonging to the MADS‐box transcription factor family have been cloned in the last few years and the functions of some of them have been investigated in detail. Here we review the current state of knowledge on rice flower development and focus on MADS‐box genes that determine floral organ identity in this species. We compare results obtained in rice with the information known forArabidopsisand the differences between these two species are discussed.
Reproductive Biology of the Andean Shrub Discaria nana (Rhamnaceae)
Authors: Medan D.
Published: March 2003

Abstract: The widely‐held view that the frequency of self‐compatibility increases at higher elevations has been questioned for communities of the southern Andes. The study of pollination biology of obligate outcrossers with wide altitudinal range may provide clues on how plants can remain reproductively successful in increasingly hostile environments without resorting to selfing. I studied the phenology, pollinator assemblages, breeding system and maternal success of the perennial entomophile outcrosser, Discaria nana, across a 1200‐m elevation span in the Andes of Mendoza and Neuquén, Argentina (34° ‐ 37°S). D. nana behaved as self‐incompatible throughout the studied gradient. At the higher site proportionally fewer flowers were pollinated, stigmatic loads were smaller and number of visitor species was lower than at low altitude; however, natural fruit set was 3.6 times higher and seed set 3.3 times higher. As a non‐exclusive explanation, it is proposed that increased maternal success reflected better pollination quality at the higher site, to which several factors seemed to contribute. At higher altitude D. nana a) exhibited mutualisms with a high proportion of the available pollen vectors, b) had a higher rate of specialized pollinators (Lepidoptera, obligate nectar feeders) to unspecialized ones (Diptera, pollen and mixed feeders) in the visitor assemblage which would reduce ineffective (i.e. self) pollination because nectar feeders visited both male and female phase flowers and pollen feeders favoured male phase flowers, c) had an extended floral longevity (especially the female phase), and d) showed an increased floral display (as number of flowers per unit plant area). Differential rewarding through more concentrated nectar may explain the change in assemblage composition. The flowers' reverse herkogamy (i.e. the location of the stigma below the anthers) seemed to enhance the beneficial effects of the abundance of more effective pollinators.
Transposon telomeres are widely distributed in the
Drosophila
genus:
TART
elements in the
virilis
group
Authors: Casacuberta Elena , Pardue Mary-Lou
Published: March 2003

Telomeres of most animals, plants, and unicellular eukaryotes are made up of tandem arrays of repeated DNA sequences produced by the enzyme telomerase.
Drosophila melanogaster
has an unusual variation on this theme; telomeres consist of tandem arrays of sequences produced by successive transpositions of two non-LTR retrotransposons,
HeT-A
and
TART
. To explore the phylogenetic distribution of these variant telomeres, we have looked for
TART
homologues in a distantly related
Drosophila
species,
virilis
. We have found elements that, despite many differences in nucleotide sequence, retain significant amino acid similarity to
TART
from
D. melanogaster
. These
D. virilis TART
elements have features that characterize
TART
elements in
D. melanogaster
: (
i
) they are found in tandem arrays on chromosome ends, (
ii
) they are not found in euchromatin, and (
iii
) they produce both sense and antisense transcripts, with the antisense RNA being in excess. The
D. virilis TART
elements have one surprising feature: both of the ORFs contain long stretches of the trinucleotide repeat CAX, encoding polyglutamine (with a few interspersed histidines). These long polyglutamine stretches are conserved in the three
D. virilis
elements sequenced. They do not interrupt any domains of known function in the
TART
proteins and are not seen in
TART
proteins from other species. Comparison of the
D. virilis
and
D. melanogaster
telomeres suggests that the retrotransposon mechanism of telomere maintenance may have arisen before the separation of the genus
Drosophila
.
Metabolic incorporation of unnatural sialic acids into
Haemophilus ducreyi
lipooligosaccharides
Authors: Goon Scarlett , Schilling Birgit , Tullius Michael V. , Gibson Bradford W. , Bertozzi Carolyn R.
Published: March 2003

The lipooligosaccharides (LOS) of
Haemophilus ducreyi
are highly sialylated, a modification that has been implicated in resistance to host defense and in virulence. In previous work, we demonstrated that
H. ducreyi
scavenges sialic acid from the extracellular milieu and incorporates those residues into LOS. Here we report that
H. ducreyi
can use unnatural sialic acids bearing elongated
N
-acyl groups from three to seven carbon atoms in length, resulting in outer membrane presentation of unnatural sialyl-LOS. The unnatural variant comprises ≈90% of cell surface sialosides when exogenous substrates are added to the media at micromolar concentrations, despite the availability of natural sialic acid in the growth media. Although they represent the majority of cell surface sialosides, analogs with longer
N
-acyl groups diminish the overall level of LOS sialylation, culminating in complete inhibition of LOS sialylation by
N
-octanoyl sialic acid. Thus, sialylation of
H. ducreyi
LOS can be modulated with respect to the structure of the terminal sialic acid residue and the extent to which the LOS acceptor is modified by supplying the bacteria with various sialic acid analogs.
Large-scale delineation of secreted protein biomarkers overexpressed in cancer tissue and serum
Authors: Welsh John B. , Sapinoso Lisa M. , Kern Suzanne G. , Brown David A. , Liu Tao , Bauskin Asne R. , Ward Robyn L. , Hawkins Nicholas J. , Quinn David I. , Russell Pamela J. , Sutherland Robert L. , Breit Samuel N. , Moskaluk Christopher A. , Frierson Henry F. , Hampton Garret M.
Published: March 2003

Genetic alterations in tumor cells often lead to the emergence of growth-stimulatory autocrine and paracrine signals, involving overexpression of secreted peptide growth factors, cytokines, and hormones. Increased levels of these soluble proteins may be exploited for cancer diagnosis and management or as points of therapeutic intervention. Here, we combined the use of controlled vocabulary terms and sequence-based algorithms to predict genes encoding secreted proteins from among ≈12,500 sequences represented on oligonucleotide microarrays. Expression of these genes was queried in 150 carcinomas from 10 anatomic sites of origin and compared with 46 normal tissues derived from the corresponding sites of tumor origin and other body tissues and organs. Of 74 different genes identified as overexpressed in cancer tissues, several encode proteins with demonstrated clinical diagnostic application, such as α-fetoprotein in liver carcinoma, and kallikreins 6 and 10 in ovarian cancer, or therapeutic utility, such as gastrin-releasing peptide/bombesin in lung carcinomas. We show that several of the other candidate genes encode proteins with high levels of tumor-associated expression by immunohistochemistry on tissue microarrays and further demonstrate significantly elevated levels of another novel candidate protein, macrophage inhibitory cytokine 1, a distant member of the tranforming growth factor-β superfamily, in the serum of patients with metastatic prostate, breast, and colorectal carcinomas. Our results suggest that the combination of annotation/protein sequence analysis, transcript profiling, immunohistochemistry, and immunoassay is a powerful approach for delineating candidate biomarkers with potential clinical significance and may be broadly applicable to other human diseases.
The structure of the inter-SH2 domain of class IA phosphoinositide 3-kinase determined by site-directed spin labeling EPR and homology modeling
Authors: Fu Zheng , Aronoff-Spencer Eliah , Backer Jonathan M. , Gerfen Gary J.
Published: March 2003

Phosphoinositide (PI) 3-kinases catalyze the phosphorylation of the D3 position of the inositol ring of PI, and its phosphorylated derivatives and play important roles in many intracellular signal transducing pathways. Class IA PI3-kinases contain distinct regulatory (p85) and catalytic (p110) subunits. p110 is stabilized and inhibited by constitutive association with p85, and is disinhibited when the SH2 domains of p85 bind to tyrosyl-phosphorylated proteins. Because the two subunits do not dissociate, disinhibition of p110 presumably occurs by an allosteric mechanism. To explore the means by which p85 regulates the activity of p110, structures of the inter-SH2 domain of p85 were determined with and without phosphopeptide by using a combination of site directed spin labeling EPR and homology modeling and molecular dynamics. The inter-SH2 domain is assigned as a rigid anti-parallel coiled-coil whose primary function is to bind p110, facilitating inhibition of p110 by the N-terminal SH2 domain of p85.
Spectroscopic and morphological studies of human retinal lipofuscin granules
Authors: Haralampus-Grynaviski Nicole M. , Lamb Laura E. , Clancy Christine M. R. , Skumatz Christine , Burke Janice M. , Sarna Tadeusz , Simon John D.
Published: March 2003

The emission properties of ocular lipofuscin granules isolated from human retinal pigment epithelial cells are examined by using steady-state fluorescence spectroscopy and spectrally resolved confocal microscopy. The shape of the emission spectrum of a thick sample of lipofuscin granules dried on glass varies with excitation energy. The polarization of this emission is wavelength-dependent, exhibiting significant polarization near the excitation wavelength and becoming mostly depolarized over the majority of the emission spectrum. These results show that the yellow-emitting fluorophores [e.g., A2E (2-[2,6-dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1
E
,3
E
,5
E
,7
E
-octatetraenyl]-1-(2-hydroxyethyl)-4-[4-methyl-6-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1
E
,3
E
,5
E
-hexatrienyl]-pyridinium)] are excited as a result of energy transfer within the granules and therefore are not the dominant blue-absorbing chromophores within lipofuscin granules. Atomic force microscopy images show lipofuscin granules to be an aggregated structure. Bulk and
in vivo
emission measurements must therefore take into account the effect of Raleigh scattering. When corrected for scattering, the emission spectrum of a thick lipofuscin deposit or intracellular lipofuscin resembles that for A2E. The sum of the emission spectra of a collection of individual granules also resembles the emission spectrum of A2E, but the spectrum of individual granules varies significantly. This result suggests that the agreement between the emission spectra of lipofuscin and A2E is fortuitous, and the collective data indicate the presence of several blue-absorbing chromophores in lipofuscin and show A2E is not the dominant yellow-emitting fluorophore in many of the granules studied.
Protein pathway and complex clustering of correlated mRNA and protein expression analyses in
Saccharomyces
cerevisiae
Authors: Washburn Michael P. , Koller Antonius , Oshiro Guy , Ulaszek Ryan R. , Plouffe David , Deciu Cosmin , Winzeler Elizabeth , Yates John R.
Published: March 2003

The mRNA and protein expression in
Saccharomyces cerevisiae
cultured in rich or minimal media was analyzed by oligonucleotide arrays and quantitative multidimensional protein identification technology. The overall correlation between mRNA and protein expression was weakly positive with a Spearman rank correlation coefficient of 0.45 for 678 loci. To place the data sets in a proper biological context, a clustering approach based on protein pathways and protein complexes was implemented. Protein expression levels were transcriptionally controlled for not only single loci but for entire protein pathways (e.g., Met, Arg, and Leu biosynthetic pathways). In contrast, the protein expression of loci in several protein complexes (e.g., SPT, COPI, and ribosome) was posttranscriptionally controlled. The coupling of the methods described provided insight into the biology of
S. cerevisiae
and a clustering strategy by which future studies should be based.