bluuebunny/crossref_metadata_2025 huggingface dataset:
Preventing infective complications following leech therapy: Is practice keeping pace with current research?
Authors: Whitaker Iain S. , Kamya Cyril , Azzopardi Ernest A. , Graf Joerg , Kon Moshe , Lineaweaver William C.
Published: April 2009

Background:

Despite several publications strongly advocating prophylactic antibiotics during leech therapy, and recent primary articles shedding new light on the microbiota of leeches, many units either do not use antibiotic prophylaxis, or are continuing to use ineffective agents.

Methods:

A 5‐year follow‐up of plastic surgery units in the United Kingdom and the Republic of Ireland was conducted in 2007 to ascertain current practice regarding the use of prophylactic antibiotics with leech therapy. A comprehensive literature search investigated primary research articles regarding the microbiota of leeches to update the reconstructive surgery community.

Results:

Despite published evidence to support the use of prophylactic antibiotics during leech therapy, 24% of units do not use antibiotic prophylaxis and 57% of those using antibiotics are using potentially ineffective agents. Advanced molecular genetic techniques, which allow accurate characterization of both culturable and nonculturable microbiota of the leech digestive tract, show a wider diversity than at first thought, with variable antiobiotic resistance profiles.

Conclusions:

Despite infection due to leech therapy being a well known and relatively common complication, many units are not using appropriate antibiotic prophylaxis. © 2009 Wiley‐Liss, Inc. Microsurgery 2009.
Properties and least‐squares problems for row extended matrices
Authors: Zhao Lijun , Hu Xiyan , Zhang Lei
Published: April 2009

In this paper, we discuss basic properties, a least‐squares problem for row extended matrices and the associated approximation problem. First, we obtain their basic properties by applying their particular structure. Then we derive a general representation of the solutions to the least‐squares problem, and we obtain an expression for the solution to the associated approximation problem. Finally, we provide a perturbation analysis and a perturbation bound for the best approximate solution. The results are illustrated by numerical examples. Copyright © 2009 John Wiley & Sons, Ltd.
An adaptive mesh refinement method for solution of the transported PDF equation
Authors: Olivieri D. A. , Fairweather M. , Falle S. A. E. G.
Published: April 2009

This paper presents the results of an investigation into a possible alternative to Monte Carlo methods for solving the transported probability density function (PDF) equation for scalars (compositions). The method uses a finite‐volume approach combined with adaptive mesh refinement (AMR) in a multi‐dimensional compositional space. Comparisons are made between the new method and Monte Carlo solutions for analytical test cases involving the reaction of two or three chemical species. These tests demonstrate the potential of the new method in terms of both accuracy and run time. Additional test cases involving various models for molecular mixing were also conducted with similar conclusions. Copyright © 2009 John Wiley & Sons, Ltd.
A boundary face method for potential problems in three dimensions
Authors: Zhang Jianming , Qin Xianyun , Han Xu , Li Guangyao
Published: April 2009

This work presents a new implementation of the boundary node method (BNM) for numerical solution of Laplace's equation. By coupling the boundary integral equations and the moving least‐squares (MLS) approximation, the BNM is a boundary‐type meshless method. However, it still uses the standard elements for boundary integration and approximation of the geometry, thus loses the advantages of the meshless methods. In our implementation, here called the boundary face method, the boundary integration is performed on boundary faces, which are represented in parametric form exactly as the boundary representation data structure in solid modeling. The integrand quantities, such as the coordinates of Gauss integration points, Jacobian and out normal are calculated directly from the faces rather than from elements. In order to deal with thin structures, a mixed variable interpolation scheme of 1‐D MLS and Lagrange Polynomial for long and narrow faces. An adaptive integration scheme for nearly singular integrals has been developed. Numerical examples show that our implementation can provide much more accurate results than the BNM, and keep reasonable accuracy in some extreme cases, such as very irregular distribution of nodes and thin shells. Copyright © 2009 John Wiley & Sons, Ltd.
Initial evidence on whether use of professional fundraising services increases fundraising effectiveness
Authors: Marudas Nicholas P. , Jacobs Fred A.
Published: April 2009

We provide initial evidence on whether use of professional fundraising services by US nonprofit organizations (NPOs) increases the effectiveness of NPOs' fundraising efforts. To a well‐tested model of organization‐level donations, we add an interaction term that captures the impact that professional fundraising fees an NPO incurs has on the effectiveness of an NPOs' spending on fundraising in raising donations. We find that professional fundraising fees has a significant positive impact on the effectiveness of fundraising efforts in raising donations for NPOs in the full, education, and health samples, but no impact for NPOs in the arts and human services samples. For NPOs in the full sample and NPOs in the education sample, one quarter of the effect of fundraising on donations stems from the positive impact of professional fundraising services on the effectiveness of fundraising in raising donations. For NPOs in the health sample, one half of the effect of fundraising on donations stems from the positive impact of professional fundraising services on the effectiveness of fundraising in raising donations. These results suggest that professional fundraising services significantly enhance the effectiveness of fundraising for these types of NPOs. While the results of this study seem to confirm the decisions of managers of education and health NPOs to utilize professional fundraising services, the results also suggest that managers of arts and human services NPOs may want to reconsider using professional fundraising services, at least the types of services they currently purchase and the way they currently utilize such services.

Copyright © 2009 John Wiley & Sons, Ltd.
Preparation and properties of PP/PC/POE blends
Authors: Dai Shanshan , Ye Lin , Hu Guohua
Published: April 2009

In order to develop PP (polypropylene)‐based blends with balanced toughness and rigidity, the poly‐blends of PP/PC (polycarbonate)/POE (ethylene–octene copolymer) were prepared by applying styrene–ethylene–propylene–styrene (SEPS) as the macromolecular compatibilizer. The compatibilizing effect was studied in terms of the mechanical, morphologies and thermal properties, and the compatibilized PP‐based blends presented remarkable improvement in impact toughness and balanced tensile strength due to the formed special morphology structure. Additionally, by preparing the pre‐blend of PC/SEPS, the melt viscosity of the PP matrix can match that of the dispersed phase PC and POE, which led to a further improvement in the mechanical property of the blends. Copyright © 2009 John Wiley & Sons, Ltd.
Eisen‐, Calcium‐ und Magnesium‐Salze. Chemie und Eigenschaften
Authors: Ude Christian , Schubert‐Zsilavecz Manfred
Published: April 2009

Zusammenfassend lässt sich sagen, dass Calcium, Magnesium und Eisen in der modernen Pharmazie in den unterschiedlichsten Bereichen vorkommen. Besonders der menschliche Organismus reagiert sehr sensibel auf Schwankungen und einen Mangel am jeweiligen Element. Die Stoffwechselvorgänge im Körper sind somit stark abhängig von einer konstanten Homöostase. Für die Therapie einer Mangelerscheinung ist die Auswahl des richtigen Präparats unumgänglich, wobei sich viele grundlegende Eigenschaften der eingesetzten Mineralpräparate leicht aus den chemischen Grundkenntnissen ableiten lassen.
Physiologische Bedeutung von Eisen. Essenziell und toxisch
Authors: Hahn Andreas
Published: April 2009

Eisen ist ein essenzielles Spurenelement und besitzt vielfältige Funktionen im Stoffwechsel. Die Homöostase erfolgt auf der Ebene der Absorption, da die Möglichkeiten der Eisen‐Exkretion stark eingeschränkt sind Unter ernährungsphysiologischen Gesichtspunkten ist weniger der absolute Eisen‐Gehalt eines Lebensmittels von Bedeutung als die Bioverfügbarkeit des Mineralstoffs. Das in Lebensmitteln tierischer Herkunft enthaltene Hämeisen ist weitaus besser verwertbar als die in Pflanzen vorkommenden anorganischen Verbindungen. Weltweit betrachtet ist Eisen der Nährstoff, bei dem am häufigsten Mangelerscheinungen auftreten.

In Deutschland erreichen mehr als drei Viertel der Frauen im gebärfähigen Alter nicht die von den Fachgesellschaften empfohlene Zufuhr des Mineralstoffs. Ausgeprägte Mangelerscheinungen mit funktionellen Einschränkungen sind dennoch vergleichsweise selten. Eine sehr hohe Aufnahme an Hämeisen scheint das Risiko für Tumoren des Dickdarms zu erhöhen. Die zeitweise postulierte Hypothese, wonach ein hoher Eisen‐Status die Prävalenz von Herz‐Kreislauf‐Erkrankungen erhöht, gilt hingegen als widerlegt.
Magnesium‐Verbindungen. Aufnahme, Funktionen und therapeutische Aspekte
Authors: Eder Klaus
Published: April 2009

Magnesium ist nach dem Kalium das mengenmäßig zweithäufigste intrazelluläre mineralische Element in unserem Körper. Aufgrund seiner vielfältigen Funktionen im Körper führt eine unzureichende Versorgung an Magnesium zu einem breiten Spektrum an Mangelsymptomen. Der Magnesium‐Haushalt des Körpers wird durch Resorption aus dem Darm, Ausscheidung über den Stuhl und den Urin sowie Einlagerung oder Freisetzung in das bzw. aus dem Skelett reguliert. Die Resorption von Magnesium erfolgt über den kompletten Darm durch zwei verschiedene Prozesse, zum einen Carrier‐vermittelt, zum anderen parazellulär durch passive Diffusion. Die Resorptionsrate aus der Nahrung liegt normalerweise bei 35 bis 55 %. Bei fettreicher Nahrung oder der Aufnahme verschiedener Nahrungsinhaltsstoffe, die die Magnesium‐Resorption hemmen wie Phosphat, Phytat oder Oxalat, kann sie aber deutlich reduziert sein. Für die Wirksamkeit von Magnesium‐Präparaten spielt die intestinale Bioverfügbarkeit des Magnesiums eine entscheidende Rolle. Organische Magnesium‐Verbindungen wie das Citrat, Aspartat, Aspartat‐hydrochlorid, Gluconat oder Aminosäurekomplexe haben eine deutlich höhere Bioverfügbarkeit als anorganische Magnesium‐Salze wie das Carbonat, Oxid oder Sulfat (mit Ausnahme von Chlorid). Organische Magnesium‐Verbindungen sind als Supplemente daher den weniger gut resorbierbaren anorganischen Verbindungen wie Magnesiumoxid oder ‐carbonat vorzuziehen.
Cellular mRNA expressions of anti‐oxidant factors in the blood of preeclamptic women
Authors: Nakamura Masamitsu , Sekizawa Akihiko , Purwosunu Yuditiya , Okazaki Shiho , Farina Antonio , Wibowo Noroyono , Shimizu Hanako , Okai Takashi
Published: April 2009

Objective

To assess the alterations of mRNA expressions associated with oxidative stress in the cellular component of blood from pregnant women with pre‐eclampsia.

Methods

Peripheral blood samples were obtained from pregnant women with and without pre‐eclampsia. Cellular RNA was subjected to a reverse transcription polymerase chain reaction (PCR) assay in order to examine the mRNA distribution among women with pre‐eclampsia (n = 24) and control subjects (n = 24) during 35–41 weeks of gestation. The data were analyzed by non‐parametric statistics.

Results

Significant differences between the pre‐eclampsia subjects and the controls were observed in the gene expressions associated with oxidative stress. Lower values in the pre‐eclampsia group were found for heme oxygenase (HO)‐1, HO‐2, catalase and superoxide dismutase (SOD). The HO‐1, HO‐2 and the catalase levels significantly correlated with proteinuria, and the HO‐2 level with systolic blood pressure.

Conclusion

Significantly lower concentrations of HO‐1, HO‐2, SOD and catalase are found in the cellular component of blood from pre‐eclamptic patients. The values correlate with the severity of pre‐eclampsia. These findings indicate that enhanced oxidative stress and a decrease in the number of anti‐oxidant enzymes may be associated with pre‐eclampsia. Copyright © 2009 John Wiley & Sons, Ltd.
The nuchal translucency and the fetal heart: a literature review
Authors: Clur S. A. , Ottenkamp J. , Bilardo C. M.
Published: April 2009

In this overview the current knowledge of the relationship between an increased nuchal translucency (NT) measurement and fetal heart structure and function in chromosomally normal fetuses is reviewed. Relevant pathophysiological theories behind the increased NT are discussed. Fetuses with an increased NT have an increased risk for congenital heart disease (CHD) with no particular bias for one form of CHD over another. This risk increases with increasing NT measurement. Although the NT measurement is only a modestly effective screening tool for all CHD when used alone, it may indeed be effective in identifying specific CHD “likely to benefit” from prenatal diagnosis. The combination of an increased NT, tricuspid regurgitation and an abnormal ductus venosus (DV) Doppler flow profile, is a strong marker for CHD. A fetal echocardiogram should be performed at 20 weeks' gestation in fetuses with an NT ≥ 95th percentile but < 99th percentile. When the NT measurement is ≥ 99th percentile, or when tricuspid regurgitation and/or an abnormal DV flow pattern is found along with the increased NT, an earlier echocardiogram is indicated, followed by a repeat scan at around 20 weeks' gestation. The resultant increased demand for early fetal echocardiography and sonographers with this special expertise needs to be planned and provided for. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of highly active antiretroviral therapy (HAART) on cholesterol in HIV‐1 infected children: a retrospective cohort study
Authors: Kim Jason Y. , Zaoutis Theoklis , Chu Jaclyn , Zhao Huaqing , Rutstein Richard
Published: April 2009

Objective

To determine the extent to which different highly active antiretroviral therapy (HAART) regimens pose risks for hypercholesterolemia in children with perinatal HIV‐1.

Methods

A single center, retrospective cohort study examined different HAART regimens and total cholesterol (TC) levels. The primary outcomes were TC levels > 180, > 200 mg/dl. HAART was defined as multiple nucleoside analog reverse transcriptase inhibitors (NRTI), NRTI and protease inhibitor (PI) combinations (NRTI/PI), and NRTI and non‐nucleoside analog reverse transcriptase inhibitor (NNRTI) combinations (NRTI/NNRTI). Controls were HIV‐1 infected children while on no medications (No MED). Univariate and multivariable Cox regression models generated hazard ratios for each of the primary outcomes with duration of therapy in the model.

Results

Of the 178 HIV‐1 infected children eligible for study, 72.4% had TC > 180 mg/dl, 53.4% had TC > 200 mg/dl. For TC > 200, the multivariable analysis showed increased risk with NRTI/NNRTI (HR: 1.86, 95%CI: 1.34–2.19) and NRTI/PI (HR: 3.45, 95%CI: 2.65–4.51) when compared to No MED. Compared to NRTI/NNRTI, NRTI/PI increased the risk for TC > 200 mg/dl (HR: 1.86, 95%CI: 1.45–2.39) in the multivariable model.

Conclusions

In vertically acquired HIV‐1 infected children, HAART elevates the risk of hypercholesterolemia. NRTI/PI increased risk of TC levels threefold, while NRTI/NNRTI increased risk twofold over No MED. Copyright © 2009 John Wiley & Sons, Ltd.
Psychotropic drug use in the Norwegian general population in 2005: data from the Norwegian Prescription Database
Authors: Kjosavik Svein R , Ruths Sabine , Hunskaar Steinar
Published: April 2009

Purpose

To analyse psychotropic drug utilisation patterns in the general population of Norway in 2005.

Methods

Data on 4 163 045 prescriptions of psychotropic drugs dispensed at all pharmacies in Norway during 2005 were extracted from The Norwegian Prescription Database (NorPD), including antipsychotics (ATC‐code N05A), anxiolytics (N05B), hypnotics (N05C) and antidepressants (N06A). This information was merged with data concerning the 3857 general practitioners (GPs) from the Norwegian Regular GP Scheme.

Results

A total of 705 230 individuals, or 15.3% of the general population, received at least one prescription of a psychotropic drug. The figures for the four therapeutic subgroups were 2.4% for antipsychotics, 6.2% for anxiolytics, 7.9% for hypnotics and 6.0% for antidepressants, respectively. For all subgroups, prevalence was higher among women than among men, and increased steadily by patients' age. The mean annual drug volume per patient was highest among persons aged 40–59 years, except for hypnotics where it continued to increase with age. GPs prescribed 80% of overall psychotropic drug volume, psychiatrists 5%, and other prescribers 15%. The proportion of the drugs issued by the three prescriber groups differed with the patients' age group. While children and adolescents received a relatively large share from paediatricians and child and adolescent psychiatrists, adults mostly got their prescriptions from GPs.

Conclusions

The majority of psychotropic drugs were prescribed by GPs. Overall drug use increased significantly, and psychiatrists' contribution decreased significantly with patients' age. The quality of pharmacological treatment for mental health problems of the general and aging population therefore relies mainly on the GPs. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of multiwall carbon nanotubes on the mechanical properties and unusual crystallization behavior in melt‐mixed co‐continuous blends of polyamide6 and acrylonitrile butadiene styrene
Authors: Bose Suryasarathi , Bhattacharyya Arup R. , Häußler Liane , Pötschke Petra
Published: April 2009

The mechanical and the crystallization behavior of melt‐mixed cocontinuous blends of polyamide6 (PA6) and acrylonitrile butadiene styrene were studied in presence of multiwall carbon nanotubes (MWNT). Young's modulus was observed to be significantly improved with increasing concentration of MWNT, while only moderate improvements were observed in the tensile strength. To overcome the van der Waals' forces between MWNT a unique modifier, sodium salt of 6 amino hexanoic acid (Na‐AHA) was employed where it was envisaged that specific interactions between Na+ of the modifier and the delocalized “π‐electron” clouds of MWNT would lead to significant debundlling of the tubes. The mechanical properties of the blends with Na‐AHA modified MWNT were found to be improved as compared to the blends with purified MWNT however, were found to be adversely affected above certain concentration of Na‐AHA in the blends. Dynamic mechanical thermal analysis supported the plasticization effect induced by Na‐AHA manifesting in decrease in the glass transition temperature of PA6 in the blends with Na‐AHA modified MWNT. Differential scanning calorimetry results showed two crystallization exotherms for PA6 in the blends with both purified and Na‐AHA modified MWNT. This unusual crystallization behavior of PA6 was addressed in context to confined crystallization of PA6 in the tube “network‐like” structure. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Preparation of highly H+ permeable sulfonated poly(ether ether ketone) cation exchange membranes and their applications in electro‐generation of thioglycolic acid
Authors: Huang Xuehong , Chen Zhen , Lin Pu , Huang Jinbiao , Chen Wenjian
Published: April 2009

BACKGROUND: Sulfonated poly(ether ether ketone) (SPEEK) was successfully synthesized from sulfonated 4,4′‐difluorobenzophenone, 4,4′‐difluorobenzophenone and bisphenol A. SPEEK cation exchange membranes were prepared by the casting method. The composition and morphology of SPEEK were characterized using Fourier transform infrared and 1H NMR spectroscopies, respectively. The ion exchange capacity (IEC), water uptake and degree of swelling of the membranes were also investigated. SPEEK120 was used as a separator in an electrolysis cell to produce thioglycolic acid (TGA).

RESULTS: SPEEK polymerization was carried out at 145 and 175 °C for 10 h. The IEC of the SPEEK membranes was measured as 0.24–2.02 meq g−1 and the water uptake as 2.26–26.45%. The degree of swelling of the membranes was 1.71–15.28%. TGA was effectively prepared by electro‐reduction of dithioglycolic acid. The current efficiency peaked at 58.31% at room temperature with a current density of 15 mA cm−2.

CONCLUSION: SPEEK120 membrane shows good dimensional stability and H+ permeability. Compared to the traditional metal‐reduction method, the current electro‐reduction technique avoids the use of zinc powder and so reduces environmental pollution. Copyright © 2009 Society of Chemical Industry
Simulating material inhomogeneities and defects in CIGS thin‐film solar cells
Authors: Malm Ulf , Edoff Marika
Published: April 2009

Thin‐film CIGS solar cells are simulated using a hybrid model consisting of a distributed form of the analytical one diode model paired with a numerical finite element model of the d.c. conduction in the front contact layers. Variations in material quality over the substrate surface, from measured J–V curves, are incorporated into the model and the effects of cell width and window layer thickness are evaluated for homogeneous and inhomogeneous material quality. Furthermore, the effects of discrete shunt defects of different sizes are modelled, and in different positions on the cell surface. The results from optimizing cell width and window layer thickness show that the effects of material inhomogeneities include a small shift of the optimal parameters together with a less pronounced maximum. As expected, the defect size is important to the shunt conductance parameter of the resulting J–V curves. The passivating effect of the highly resistive ZnO layer is confirmed. Copyright © 2009 John Wiley & Sons, Ltd.
Reciprocity between electroluminescence and quantum efficiency used for the characterization of silicon solar cells
Authors: Kirchartz Thomas , Helbig Anke , Reetz Wilfried , Reuter Michael , Werner Jürgen H. , Rau Uwe
Published: April 2009

Spectrally and spatially resolved electroluminescence emission of crystalline silicon solar cells is interpreted in terms of two electro‐optical reciprocity relations. The first relation links the photovoltaic quantum efficiency to the electroluminescence spectrum. Both methods contain information on recombination and the optical pathlength of the incident light, simultaneously. From the electroluminescence spectrum, we derive the pathlength enhancement factor of textured and untextured crystalline silicon solar cells. Further, we use local quantum efficiency measurements to quantitatively explain light induced current as well as panchromatic electroluminescence images. A second reciprocity relation connects open circuit voltage of a solar cell with the light emitting diode quantum efficiency of the same device. For a given quality of light trapping and a given open circuit voltage, we predict the attainable LED quantum efficiency and verify our results experimentally. Copyright © 2009 John Wiley & Sons, Ltd.
The Zn(S,O,OH)/ZnMgO buffer in thin‐film Cu(In,Ga)(Se,S)2‐based solar cells part II: Magnetron sputtering of the ZnMgO buffer layer for in‐line co‐evaporated Cu(In,Ga)Se2 solar cells
Authors: Hariskos D. , Fuchs B. , Menner R. , Naghavi N. , Hubert C. , Lincot D. , Powalla M.
Published: April 2009

A ZnS/Zn1‐xMgxO buffer combination was developed to replace the CdS/i‐ZnO layers in in‐line co‐evaporated Cu(In,Ga)Se2(CIGS)‐based solar cells. The ZnS was deposited by the chemical bath deposition (CBD) technique and the Zn1‐xMgxO layer by RF magnetron sputtering from ceramic targets. The [Mg]/([Mg] + [Zn]) ratio in the target was varied between x = 0·0 and 0·4. The composition, the crystal structure, and the optical properties of the resulting layers were analyzed. Small laboratory cells and 10 × 10 cm2 modules were realized with high reproducibility and enhanced stability. The transmission is improved in the wavelength region between 330 and 550 nm for the ZnS/Zn1‐xMgxO layers. Therefore, a large gain in the short‐circuit current density up to 12% was obtained, which resulted in higher conversion efficiencies up to 9% relative as compared to cells with the CdS/i‐ZnO buffer system. Peak efficiencies of 18% with small laboratory cells and 15·2% with 10 × 10 cm2 mini‐modules were demonstrated. Copyright © 2009 John Wiley & Sons, Ltd.
Die zweite Entdeckung des Top‐Quarks
Authors: Hirschbühl Dominik , Lück Jan , Müller Thomas , Wagner Wolfgang
Published: April 2009

Das Top‐Quark ist das schwerste bekannte Elementarteilchen. Mit einer Masse von rund 173 GeV ist es fast so schwer wie ein Goldatom und etwa 20 000‐mal schwerer als ein Up‐Quark, das zusammen mit dem Down‐Quark ein Proton aufbaut. Dieser riesige Unterschied ließ einige Theoretiker vermuten, das Top‐Quark könne vielleicht Eigenschaften besitzen, die das Standardmodell der Elementarteilchenphysik nicht beschreibt. Neue Ergebnisse vom Proton‐Antiproton‐Collider Tevatron am Fermilab bestätigen nun auch in diesem Bereich die Vorhersagen des Standardmodells.
Schüler in die Wissenschaft
Authors: Bilow Uta , Kobel Michael
Published: April 2009

Wissenschaft zum Ausprobieren kommt bei Schülern grundsätzlich gut an, vor allem, wenn es sich um moderne Physik handelt. Bei dem vor fünf Jahren gestarteten internationalen Projekt Hands on Particle Physics Masterclasses können Jugendliche das Fachgebiet der Teilchenphysik kennenlernen und aktiv erleben. Vom 16. März bis 4. April hatten sie wieder Gelegenheit dazu.
Glitzernde Tautropfen in der Morgensonne
Authors: Schlichting Hans‐J.
Published: April 2009

Lässt man in der frühen Morgensonne den Blick über die feuchten Blätter von Pflanzen schweifen, so sieht man vereinzelte Tautropfen wie funkelnde Edelsteine im Wechsel der Blickrichtung in verschiedenen Farben aufblitzen. Die Farben lassen sich mit einem fotografischen Trick hervorheben.
Proteomic analysis of the development and germination of date palm (Phoenix dactylifera L.) zygotic embryos
Authors: Sghaier‐Hammami Besma , Valledor Luis , Drira Noureddine , Jorrin‐Novo Jesús V.
Published: April 2009

By using a comparative proteomic approach (2‐DE coupled to MS/MS), the development, maturation, and germination of date palm zygotic embryos, have been studied. Proteins were trichloroacetic acid (TCA)–acetone–phenol extracted and resolved by 2‐DE in the 5–8 pH range. The total protein content and the number of spots resolved increased from early (12 weeks after pollination (WAP); 68.96 mg/g DW: 207 spots) to late (17 WAP; 240.85 mg/g DW: 261 spots) stages, decreasing upon germination (from 120.8 mg/g DW: 273 spots in mature embryos to 26.35 mg/g DW: 87 spots in 15 days after germination). Up to 194 spots showed qualitative or quantitative differences between stages. Statistical analysis of spot variation was performed by PCA, obtaining a more accurate grouping of the samples and determining the most discriminant spots. Samples were also clustered based on Pearson distance and Ward's minimum distance. Sixty‐five variable spots were subjected to MS analysis, resulting in 21 identifications. The identified proteins belong to the following functional categories: enzymes of glycolysis, tricarboxylic acid cycle, and carbohydrate biosynthesis, protein translation, storage (glutelin), and stress‐related proteins. The evolution pattern of the functional groups was examined and discussed in terms of metabolism adaptation to the different embryogenic and germination stages.
Diabetic dyslipidemia and exercise alter the plasma low‐density lipoproteome in Yucatan pigs
Authors: Richardson Matthew R. , Lai Xianyin , Dixon Joseph L. , Sturek Michael , Witzmann Frank A.
Published: April 2009

Although low‐density lipoprotein (LDL) plays a predominant role in atherogenesis, the low‐density lipoproteome has not been fully characterized. Moreover, alterations from a Western diet, diabetes, and physical inactivity on this proteome have yet to be determined. Accordingly, relative quantification was determined in LDL proteins from male Yucatan diabetic dyslipidemic (DD) swine in the early stages of atherosclerosis compared to healthy control (C) and non‐diabetic hyperlipidemic (H) swine. Importantly, coronary vascular dysfunction was prevented by aerobic exercise training in these animals (DDX) without altering total LDL concentration. Using 2‐DE, Western blot, label‐free quantitative MS, and selected reaction monitoring, alterations in the abundance of apolipoproteins A‐I, B, C‐III, D, E, and J and noncovalently associated proteins were determined in LDL isolated using fast protein liquid chromatography. At least 28 unique proteins, many of which were novel, were identified with high confidence. An apolipoprotein E isoform demonstrated stronger correlation to disease (percent of coronary artery segments with intimal thickening) than some traditional risk factors (total cholesterol, LDL cholesterol, and LDL/HDL cholesterol). Taken together, this work identifies new possible biomarkers, potential therapeutic targets for atherosclerosis, and generates new hypotheses regarding the role of LDL in atherogenesis.
The cell wall and secretory proteome of a tobacco cell line synthesising secondary wall
Authors: Millar David J. , Whitelegge Julian P. , Bindschedler Laurence V. , Rayon Catherine , Boudet Alain‐Michel , Rossignol Michel , Borderies Gisèle , Bolwell G. Paul
Published: April 2009

The utility of plant secondary cell wall biomass for industrial and biofuel purposes depends upon improving cellulose amount, availability and extractability. The possibility of engineering such biomass requires much more knowledge of the genes and proteins involved in the synthesis, modification and assembly of cellulose, lignin and xylans. Proteomic data are essential to aid gene annotation and understanding of polymer biosynthesis. Comparative proteomes were determined for secondary walls of stem xylem and transgenic xylogenic cells of tobacco and detected peroxidase, cellulase, chitinase, pectinesterase and a number of defence/cell death related proteins, but not marker proteins of primary walls such as xyloglucan endotransglycosidase and expansins. Only the corresponding detergent soluble proteome of secretory microsomes from the xylogenic cultured cells, subjected to ion‐exchange chromatography, could be determined accurately since, xylem‐specific membrane yields were of poor quality from stem tissue. Among the 109 proteins analysed, many of the protein markers of the ER such as BiP, HSP70, calreticulin and calnexin were identified, together with some of the biosynthetic enzymes and associated polypeptides involved in polymer synthesis. However 53% of these endomembrane proteins failed identification despite the use of two different MS methods, leaving considerable possibilities for future identification of novel proteins involved in secondary wall polymer synthesis once full genomic data are available.
Kinetics and mechanism of the reactions of aryl chlorodithioformates with pyridines and secondary alicyclic amines
Authors: Castro Enrique A. , Gazitúa Marcela , Santos José G.
Published: April 2009

The reactions of pyridines and secondary alicyclic (SA) amines with phenyl and 4‐nitrophenyl chlorodithioformates (PClDTF and NPClDTF, respectively) are subjected to a kinetic study in aqueous ethanol (44 wt% ethanol) solution, at 25.0 °C, and an ionic strength of 0.2 M (KCl). The reactions are studied spectrophotometrically. Under amine excess, pseudo‐first‐order rate coefficients (kobs) are found. Plots of kobs versus [amine] are linear and pH independent, with slope kN. The Brønsted‐type plots (log kN vs. pKa of aminium ions) are linear for the reactions of PClDTF with SA amines (slope β of 0.3) and pyridines (β  = 0.26) and those of NPClDTF with pyridines (β = 0.30). For the reaction of NPClDTF with SA amines the Brønsted‐type plot is biphasic, with slopes β1 = 0.2 (at high pKa) and β2 = 1.1 (at low pKa). The pKa value at the center of curvature (pK) is 7.7. The magnitude of the slopes indicates that the mechanisms of these reactions are stepwise, with the formation of a zwitterionic tetrahedral intermediate as the rate‐determining step, except for the reaction of NPClDTF with SA amines where there is a change in the rate‐determining step, from formation to breakdown of the tetrahedral intermediate, as the amine basicity decreases. Copyright © 2009 John Wiley & Sons, Ltd.
DNA diffusion in aqueous solution in presence of suspended particles
Authors: Sato Hiroki , Masubuchi Yuichi , Watanabe Hiroshi
Published: April 2009

Although nanoparticles, which are comparable in size to polymer chains, are widely used as fillers to polymer matrices for developing functional and high performance materials, the dynamics of polymers constrained between solid particles has not been well elucidated. In this study, dynamics of individual polymer under such condition was investigated with fluorescent microscopy using DNA solutions as model systems. For individual T4 and λ DNA molecules in aqueous suspensions of spherical polystyrene particles with diameter of 1 μm, it was found that (i) the radius of gyration of DNA is independent of the particle volume fraction, ϕp, (ii) DNA diffusion is not sensitive to ϕp up to a certain critical ϕp where the average distance between particle surfaces is close to DNA size, and (iii) the DNA diffusion becomes slower at higher ϕp. The diffusion coefficient of DNA was larger, by a factor of 2, in the suspensions at intermediate ϕp than in the corresponding confined geometry (channel/slit between fixed walls), whereas this difference asymptotically vanished with increasing ϕp. This result suggested that the DNA diffusion in the suspensions with intermediate ϕp is accelerated by the particle motion. In fact, the diffusion coefficient measured for DNA in the suspensions was semiquantitatively described by the Rouse constraint‐release model considering the matrix effect on the probe chain diffusion. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1103–1111, 2009
The making of Calabi‐Yau spaces: Beyond toric hypersurfaces
Authors: Kreuzer M.
Published: April 2009

While Calabi‐Yau hypersurfaces in toric ambient spaces provide a huge number of examples, theoretical considerations as well as applications to string phenomenology often suggest a broader perspective. With even the question of finiteness of diffeomorphism types of CY 3‐folds unsettled, an important idea is Reid's conjecture that the moduli spaces are connected by certain singular transitions. We summarize the results of our recent construction of a large class of new CY spaces with small Picard numbers and of their mirrors via conifold transitions and discuss the benefits of other approaches to interesting locations in the web that have been or should be pursued.
Liposomal gemcitabine (GemLip)—efficient drug against hormone‐refractory Du145 and PC‐3 prostate cancer xenografts
Authors: Jantscheff Peter , Esser Norbert , Graeser Ralph , Ziroli Vittorio , Kluth Jessica , Unger Clemens , Massing Ulrich
Published: April 2009

BACKGROUND

Gemcitabine (Gemc) is an efficient chemotherapeutic drug in various cancer types (e.g., pancreas) but has only limited effects on hormone‐refractory prostate cancer (HRPCa). Since HRPCa cells are highly sensitive to even low doses of Gemc in vitro, the lack of clinical effects might be due to rapid degradation of Gemc by deaminases combined with impaired accumulation in tumor tissue and PCa cells. Liposomal formulation (GemLip) is expected to protect the entrapped cytotoxic substance from enzymatic degradation and furthermore augment its accumulation within tumor tissues due to an enhanced permeability of the tumor vessels.

METHODS

Anti‐tumoral and anti‐metastatic activity of GemLip and Gemc were investigated in two luciferase‐expressing, human hormone‐refractory PC‐3 and Du145 HRPCa xenograft models in immunodeficient mice. Tumor growth was monitored by in vivo luminescence imaging (orthotopic) or callipering (subcutaneous). Anti‐metastatic effects of treatment were determined by in vitro luciferase assay of the tissues.

RESULTS

Tumor growth of subcutaneous Du145 xenografts was significantly inhibited only by GemLip (8 mg/kg: P = 0.014 and 6 mg/kg: P = 0.011) but not by conventional Gemc (360 mg/kg). In contrast, growth of orthotopic PC‐3 xenografts was significantly inhibited by both, GemLip (P = 0.041) and Gemc (P = 0.002). The drugs furthermore strongly reduced spleen and liver metastases in this model.

CONCLUSIONS

As shown by the very low efficient concentration of GemLip, liposomal entrapment of Gemc greatly enhances its activity. GemLip has, even at very low doses, a significant anti‐tumoral and anti‐metastatic therapeutic effect in HRPCa xenografts in vivo and was beneficial even when the conventional Gemc failed. Prostate 69:1151–1163, 2009. © 2009 Wiley‐Liss, Inc.
The energy profiles of atomic conformational transition intermediates of adenylate kinase
Authors: Feng Yaping , Yang Lei , Kloczkowski Andrzej , Jernigan Robert L.
Published: April 2009

The elastic network interpolation (ENI) (Kim et al., Biophys J 2002;83:1620–1630) is a computationally efficient and physically realistic method to generate conformational transition intermediates between two forms of a given protein. However it can be asked whether these calculated conformations provide good representatives for these intermediates. In this study, we use ENI to generate conformational transition intermediates between the open form and the closed form of adenylate kinase (AK). Based on Cα‐only intermediates, we construct atomic intermediates by grafting all the atoms of known AK structures onto the Cαatoms and then perform CHARMM energy minimization to remove steric conflicts and optimize these intermediate structures. We compare the energy profiles for all intermediates from both the CHARMM force‐field and from knowledge‐based energy functions. We find that the CHARMM energies can successfully capture the two energy minima representing the open AK and closed AK forms, while the energies computed from the knowledge‐based energy functions can detect the local energy minimum representing the closed AK form and show some general features of the transition pathway with a somewhat similar energy profile as the CHARMM energies. The combinatorial extension structural alignment (Shindyalov et al., 1998;11:739–747) and the k‐means clustering algorithm are then used to show that known PDB structures closely resemble computed intermediates along the transition pathway. Proteins 2009. © 2009 Wiley‐Liss, Inc.
A method for determining the flammable limits of gases in a spherical vessel
Authors: Crowl Daniel A. , Jo Young‐do
Published: April 2009

The current method for determining the flammable limits for a gas in a closed spherical vessel is based on a specification of the maximum pressure increase during the combustion, usually from 5 to 10% of the initial ambient pressure. This approach is completely arbitrary and is not fundamentally based. For most hydrocarbons this pressure boundary and hence the flammable limits are easy to determine experimentally since an abrupt pressure drop occurs at the flammable limits as the fuel concentration in air is adjusted. However, for some species, particularly hydrogen mixed with air, the drop in maximum combustion pressure is not very abrupt and the fuel concentration can range several percentage points depending on the arbitrary criterion used for the flammable limits.

This article will discuss a new approach for determining the flammable limits for a gas in a spherical vessel. The approach is based on the maximum second derivative of pressure rise. The second derivative is indicative of an acceleration of the combustion process and is, hence, fundamentally based. Furthermore, we have identified a new approach to determine the downward propagating flammable limits based on the combustion time, that is, the time that the gas actually burns in the vessel.

Experimental data for methane and hydrogen show that the second derivative flammable limit criterion produces slightly conservative values for combustion in air. Visual inspection of the combustion during the tests showed that no visual combustion was observed at the second derivative criterion. For methane, the second derivative criterion resulted in a flammable range in air from 4.6 to 15.8% methane. For hydrogen these limits are 3.6–75.2%.

We believe that this method will provide a much more fundamentally based method to determine both the upper and lower flammable limits of upward flame propagation and also provide a means to determine the downward propagation limits in a spherical combustion vessel. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009
To what extent are soil amendments useful to control Verticillium wilt?
Authors: Goicoechea Nieves
Published: April 2009

The genus Verticillium includes several species that attack economically important crops throughout the world. The control of Verticillium spp. becomes especially difficult when they form microsclerotia that can survive in the field soil for several years. It has been common practice to fumigate soil with chemicals such as methyl bromide and/or chloropicrin to control soil‐borne fungal pathogens. Other chemicals that are used against Verticillium spp. are the antifungal antibiotic aureofungin, the fungicides benomyl, captan, carbendazim, thiram, azoxystrobin and trifloxystrobin and the plant defence activator acibenzolar‐S‐methyl. However, the potential risks involved in applying phytochemicals to crop plants for both the environment and human health, together with their limited efficacy for controlling Verticillium‐induced diseases, support the need to find alternatives to replace their use or improve their efficacy. Soil amendment with animal or plant organic debris is a cultural practice that has long been used to control Verticillium spp. However, today the organic farming industry is becoming a significant player in the global agricultural production scene. In this review, some of the main results concerning the efficacy of several soil amendments as plant protectors against Verticillium spp. are covered, and the limitations and future perspectives of such products are discussed in terms of the control of plant diseases. Copyright © 2009 Society of Chemical Industry
Trichogin GA IV: an antibacterial and protease‐resistant peptide
Authors: De Zotti Marta , Biondi Barbara , Formaggio Fernando , Toniolo Claudio , Stella Lorenzo , Park Yoonkyung , Hahm Kyung‐Soo
Published: April 2009

The antibacterial and hemolytic activities of the amphiphilic helical, membrane‐active, lipopeptaibol trichogin GA IV and its [Leu11‐OMe] analogue were compared to those of the partially helical or non‐helical 8‐meric or 4‐meric, C‐terminal short sequences, respectively. The study on trichogin GA IV was extended to several methicillin‐resistant Staphylococcus aureus strains. Using a large set of enzymes, we also evaluated the resistance to proteolysis of all of the four peptides. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Demonstration of confocal sum frequency microscopy [Phys. Status Solidi C 6, No. 1, 304–306 (2009)]
Authors: Locharoenrat Kitsakorn , Sano Haruyuki , Mizutani Goro
Published: April 2009

The magnification of the objective lens used in the above paper and the related values were erroneously reported and should be corrected. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positive mode electrospray tandem mass spectrometry of poly(methacrylic acid) oligomers
Authors: Giordanengo Rémi , Viel Stéphane , Allard‐Breton Béatrice , Thévand André , Charles Laurence
Published: April 2009

The dissociation of small poly(methacrylic acid) (PMAA) cations produced by electrospray was characterized by tandem mass spectrometry. Similarly to PMAA ions produced in the negative ion mode, the two electrosprayed cationic forms, namely [PMAA+Na]+ and [PMAA‐H+2Na]+, were shown to fragment via a major pathway consisting of successive dehydration steps. Elimination of a water molecule would occur between two consecutive acid groups in a charged‐remote mechanism and was shown to proceed as many times as pairs of acidic pendant groups were available. As a result, comparing the number of dehydration steps observed in the MS/MS spectrum of two consecutive oligomers from the polymeric distribution reveals the degree of polymerization of the molecule. Secondary less informative reactions were shown to consist of losses of CO and/or CO2, depending on the nature of the precursor ion. These fragmentation rules could be used to characterize PMAA‐based copolymers, as successfully demonstrated for a polymeric impurity in the tested PMAA sample. Copyright © 2009 John Wiley & Sons, Ltd.
Empirical evaluation of ductility factors for the special steel moment‐resisting frames in view of soil condition
Authors: Kang Cheol Kyu , Choi Byong Jeong
Published: April 2009

It is well known that the response modification factor (R) takes into account the ductility, over‐strength, redundancy and damping of structural systems. The ductility factor has played an important role in seismic design, as it is a key component of R. In this study, the ductility factors (Rμ,MDOF) of special steel moment‐resisting frames are calculated by multiplying the ductility factor of single degree of freedom (SDOF) systems (Rμ,SDOF) with the multi‐degree of freedom (MDOF) modification factors (RM). The ductility factors (Rμ,SDOF) of SDOF systems are computed from non‐linear dynamic analysis undergoing different levels of displacement ductility demands and periods when subjected to a large number of recorded earthquake ground motions. To compute the Rμ,SDOF, a group of 1,860 ground motions recorded from 47 earthquakes were considered. RM factors are proposed to account for the MDOF systems, based on previous studies. A total of 108 prototype steel frames were designed to investigate the ductility factors, considering design parameters such as the number of stories (4, 8 and 16), framing systems (perimeter frames and distributed frames), failure mechanisms (strong column‐weak beam and weak column‐strong beam), soil profiles (SA, SC and SE in Uniform Building Code 1997) and seismic zone factors (Z = 0·075, 0·2, and 0·4 in UBC 1997). The effects of these design parameters on the Rμ,MDOF of special steel‐moment‐resisting frames were investigated. Copyright © 2009 John Wiley & Sons, Ltd.