bluuebunny/crossref_metadata_2025 huggingface dataset:
Praktische Erfahrung beim Umgang mit der WU‐Richtlinie
Authors: Lingemann Martin
Published: August 2008

Für die Herstellung von Weißen Wannen liegt seit vier Jahren die Richtlinie des DAfStb vor. Sie beschreibt die Aufgaben der Planer, Konstrukteure und Ausführenden. Dabei stellen sich in der Praxis viele Probleme heraus, die einer Lösung bedürfen. Aus zahlreichen praktischen Erfahrungen wird deutlich, dass die Einschaltung erfahrener Fachunternehmen hier technische, wirtschaftliche und rechtliche Vorteile bietet.
A substrate‐selective co‐fermentation strategy with Escherichia coli produces lactate by simultaneously consuming xylose and glucose
Authors: Eiteman Mark A. , Lee Sarah A. , Altman Ronni , Altman Elliot
Published: August 2008

We describe a new approach for the simultaneous conversion of xylose and glucose sugar mixtures which potentially could be used for lignocellulosic biomass hydrolysate. In this study we used this approach to demonstrate the production of lactic acid. This process uses two substrate‐selective strains of Escherichia coli, one which is unable to consume glucose and one which is unable to consume xylose. In addition to knockouts in pflB encoding for pyruvate formate lyase, the xylose‐selective (glucose deficient) strain E. coli ALS1073 has deletions of the glk, ptsG, and manZ genes while the glucose‐selective (xylose deficient) strain E. coli ALS1074 has a xylA deletion. By combining these two strains in a single process the xylose and glucose in a mixed sugar solution are simultaneously converted to lactate. Furthermore, the biomass concentrations of each strain can readily be adjusted in order to optimize the overall product formation. This approach to the utilization of mixed sugars eliminates the problem of diauxic growth, and provides great operational flexibility. Biotechnol. Bioeng. 2009; 102: 822–827. © 2008 Wiley Periodicals, Inc.
Eyes Absent Proteins: Characterization of Substrate Specificity and Phosphatase Activity of Mutants Associated with Branchial, Otic and Renal Anomalies
Authors: Musharraf Amna , Markschies Nicole , Teichmann Kathleen , Pankratz Susann , Landgraf Kathrin , Englert Christoph , Imhof Diana
Published: August 2008

The eyes absent (Eya) genes encode a family of proteins that combine the functions of transcriptional cofactors, signal transducers and enzymes, namely protein tyrosine phosphatases. The latter activity resides in the highly conserved C‐terminal Eya domain (ED). Here, we investigated the substrate specificity of the Arabidopsis thaliana homologue (AtEya) by using low‐molecular‐weight compounds and synthetic phosphotyrosine (pY)‐containing peptides that correspond either to phosphorylation sites in proteins or to peptides that were selected through the screening of a combinatorial peptide library. AtEya displayed modest peptide substrate specificity and was sensitive to charges adjacent to pY. In general, the presence of acidic residues on the N‐terminal side of the phosphorylation site was critical for catalysis, whereas basic amino acids seemed to be preferred with respect to high‐affinity binding. We also detected significant acyl phosphatase activity of AtEya; this suggests that Eya proteins might have further substrates in vivo. In addition, we analysed the phosphatase activity of a number of variants of the mouse Eya1 protein that harbours single point mutations that were associated with branchio–oto–renal syndrome (BOR), branchio–oto syndrome (BO) and ocular defects, respectively, in humans. While BOR mutations led to a significantly reduced phosphatase activity, BO mutants as well as those that are associated with ocular defects only displayed activity that was similar to wild‐type levels.
Chemical Genetic Analysis of FOXO Nuclear–Cytoplasmic Shuttling by Using Image‐Based Cell Screening
Authors: Zanella Fabian , Rosado Aranzazú , García Beatriz , Carnero Amancio , Link Wolfgang
Published: August 2008

FOXO proteins are direct targets of PI3K/Akt signaling and they integrate the signals of several other transduction pathways at the transcriptional level. FOXO transcription factors are involved in normal cell homeostasis and neoplasia, and they are regulated by multiple post‐transcriptional modifications. In cancer research, the regulation of the FOXO factors is receiving increasing attention as their activation has been linked to cell‐cycle arrest and apoptosis. Hence, FOXO proteins have been proposed to act as tumor suppressors. Here, we applied a chemical biology approach to study the mechanisms that influence the intracellular localization of the FOXO family member FOXO3a. We established a high‐throughput cellular‐imaging assay that monitors the nuclear–cytoplasmic translocation of a GFP–FOXO3a fusion protein in tumor cells. Nuclear accumulation of fluorescent signals upon treatment with the known PI3K inhibitors LY294002, wortmannin, PIK‐75, and PI‐103 was dose dependent and agreed well with the IC50 values reported for PI3Kα inhibition in vitro. Additionally, we identified 17 compounds from a panel of 73 low‐molecular‐weight compounds capable of inducing the nuclear accumulation of GFP–FOXO. These compounds include chemicals known to interfere with components of the PI3K/Akt signaling pathway, as well as with nuclear export and Ca2+/calmodulin (CaM)‐dependent signaling events. Interestingly, the therapeutic agent vinblastine induced efficient nuclear translocation of the FOXO reporter protein. Our data illustrate the potential of chemical genetics when combined with robust and sensitive high‐content‐screening technology.
Molecular Evolution of a Defined DNA Sequence with Accumulation of Mutations in a Single Round by a Dual Approach to Random Chemical Mutagenesis (DuARCheM)
Authors: Mohan Utpal , Banerjee Uttam Chand
Published: August 2008

Directed evolution has paved the way to a new era of protein and nucleic acid molecules with improved and enhanced properties. The utmost important component of directed evolution is random mutations in a defined DNA sequence. The utility of random chemical mutagenesis in directed evolution studies is dwindling due to the inherent flaws with whole‐organism mutagenesis and the in vitro approach. Here, we report a novel Dual Approach to Random Chemical Mutagenesis (DuARCheM) to introduce random mutations in a defined DNA fragment. DuARCheM involves in vivo chemical mutagenesis and in vitro genetic manipulations. The resulting library revealed an accumulation of mutations in its members. These results imply that the parent mutation is carried in the further generations within the same library. This method might help to change random chemical mutagenesis because the combination of in vivo and in vitro approaches mimics the amplification and mutation that is performed by PCR‐based mutagenesis, and at the same time the mutations are confined to the desired gene. Moreover, the mutagen pressure is greater in chemical mutagenesis than in a Taq‐polymerase‐based error‐prone system. Concomitant amplification and mutation in the DuARCheM method leads to a better spectrum of mutants because the plasmid construct is exponentially amplified in the presence of mutagen pressure, unlike in the in vitro chemical mutagenesis system in which the template molecule does not replicate. This work is able to nullify all the disadvantages that are associated with random chemical mutagenesis, and could make random chemical mutagenesis an indispensable tool in directed evolution studies.
Screening the Structural and Functional Properties of Bicyclo‐DNA: bcox‐DNA
Authors: Luisier Samuel , Leumann Christian J.
Published: August 2008

The synthesis of two novel pyrimidine bicyclonucleosides (bcox‐nucleosides) has been accomplished. These bicyclonucleosides each carry a lipophilic benzyloxime substituent on the carbocyclic ring and show improved conformational similarity to 2′‐deoxyribonucleosides as shown by their X‐ray structures. The thymine‐containing bcox‐nucleoside was converted into the corresponding phosphoramidite building block and incorporated into oligodeoxyribonucleotides by standard phosphoramidite chemistry. Tm data with complementary RNA and DNA were measured and compared to corresponding cases of natural and unfunctionalized bc‐DNA. It was found that single incorporations of bcox residues destabilize duplexes by roughly 5 °C per modification. The destabilization was found to be due to the oxime substituent and not to the bicyclic scaffold itself. No significant alteration of the base‐pairing selectivity as a function of the modification was observed. With RNA (but not with DNA) as a complement the relative thermal destabilization of bcox‐oligothymidylates was gradually reduced and converted into a stabilizing interaction with increasing numbers of consecutive modifications. While no cellular uptake of bcox‐oligonucleotides into HeLa cells occurred without transfecting agents, a significant increase in the transfection rate relative to unmodified DNA was observed in complexation with lipofectamine.
On the Mechanism of d–f Energy Transfer in RuII/LnIII and OsII/LnIII Dyads: Dexter‐Type Energy Transfer Over a Distance of 20 Å
Authors: Lazarides Theodore , Sykes Daniel , Faulkner Stephen , Barbieri Andrea , Ward Michael D.
Published: August 2008

We have used time‐resolved luminescence methods to study rates of photoinduced energy transfer (PEnT) from [M(bipy)3]2+ (M=Ru, Os) chromophores to LnIII ions with low‐energy f–f states (Ln=Yb, Nd, Er) in d–f dyads in which the metal fragments are separated by a saturated CH2CH2 spacer, a p‐C6H4 spacer, or a p‐(C6H4)2 spacer. The finding that d→f PEnT is much faster across a conjugated p‐C6H4 spacer than it is across a shorter CH2CH2 spacer points unequivocally to a Dexter‐type energy transfer, involving electronic coupling mediated by the bridging ligand orbitals (superexchange) as the dominant mechanism. Comparison of the distance dependence of the Ru→Nd energy‐transfer rate across different conjugated spacers [p‐C6H4 or p‐(C6H4)2 groups] is also consistent with this mechanism. Observation of Ru→Nd PEnT (as demonstrated by partial quenching of the RuII‐based 3 MLCT emission (MLCT=metal‐to‐ligand charge transfer), and the growth of sensitised NdIII‐based emission at 1050 nm) over approximately 20 Å by an exchange mechanism is a departure from the normal situation with lanthanides, in which long‐range energy transfer often involves through‐space Coulombic mechanisms.
An Enolisable Barbiturate with Adjustable Hydrogen‐Bonding Structure for UV/Vis Detection of Nucleic Acid Bases and Related Compounds
Authors: Bolz Ina , Spange Stefan
Published: August 2008

The use of hydrogen‐bonding patterns in the same way as is known from DNA building blocks is a challenge for the construction of novel types of suitable chromophoric probes. This feature has been utilised for the construction of a novel type of UV/Vis probe for detection of supramolecular AAD or DAD sequences (A=hydrogen bond acceptor, D=hydrogen bond donor). Here we report on the structure of the enolisable chromophore 1‐n‐butyl‐5‐(4‐nitrophenyl)barbituric acid (1), which has an adjustable hydrogen‐bonding pattern. The position of the keto–enol equilibrium of this dye is strongly influenced both by the solvent polarity and by the chemical environment. Furthermore, the recognition properties of the barbiturate were examined by the use of seven artificial receptors: the pyridine bases 2,6‐diaminopyridine (DAP), 2,6‐diacetamidopyridine (DAC) and 2,6‐bis(trifluoroacetamido)pyridine (TFA), as well as the nucleic acid bases 9‐ethyladenine (EtAd), 9‐ethylguanine (EtGu), 1‐n‐butylcytosine (BuCy) and 1‐n‐butylthymine (BuTy). It was found that 1 can interact with these bases either through acid–base interaction or by hydrogen‐bonding complexation. The balance between the interactions is dependent both on the basicity strength and on the presence of a suitable recognition sequence in the base. The induced formation of the enol form of 1 thus causes a significant UV/Vis shift as function of the nature of the base.
Discovery of Water‐Soluble Antioxidant Flavonols without Vasorelaxant Activity
Authors: Yap Suwan , Loft Karen J. , Woodman Owen L. , Williams Spencer J.
Published: August 2008

3′,4′‐Dihydroxyflavonol (DiOHF) is a cardioprotective flavonol that can decrease ischaemia/reperfusion injury in the heart. DiOHF exhibits antioxidant and vasorelaxant properties that are thought to underlie its cardioprotective activity. A major limitation to its use for the treatment or prevention of cardiovascular disease is its poor water solubility, preventing intravenous administration at the required dosage. In this study, three novel flavonols were synthesised that bear an ionisable succinamic acid substituent at the 6‐position of the A ring with zero, one, or two hydroxy groups on the B ring. The ionised compounds possess improved aqueous solubility, dissolving at concentrations up to 10−1 m, whereas DiOHF is insoluble in water (<10−7 m). Pharmacological analysis revealed that the DiOHF‐6‐succinamic acid derivative was the best antioxidant, possessing activity similar to DiOHF, whereas vasorelaxant activity was attenuated. This compound was able to effectively scavenge superoxide from the autoxidation of pyrogallol, preventing oxidant‐induced endothelial dysfunction. DiOHF‐6‐succinamic acid represents the first antioxidant flavonol that lacks vasorelaxant activity and in the future will enable studies to cast light on the specific biological activity required for cardioprotection.
Chemotherapy with 5‐fluorouracil and a platinum compound improves outcomes in metastatic small bowel adenocarcinoma
Authors: Overman Michael J. , Kopetz Scott , Wen Sijin , Hoff Paulo M. , Fogelman David , Morris Jeffrey , Abbruzzese James L. , Ajani Jaffer A. , Wolff Robert A.
Published: August 2008

BACKGROUND.

Metastatic small bowel adenocarcinoma (SBA) has a poor prognosis. Because of the rarity of SBA, only a few studies have evaluated the role of chemotherapy in the treatment of metastatic SBA; thus, the benefit, if any, of adding a platinum compound to fluorouracil (5‐FU) is unknown. The objective of this retrospective study was to determine whether the addition of a platinum compound to 5‐FU provided any benefit in the treatment of patients with metastatic SBA.

METHODS.

The authors identified 80 patients with metastatic SBA who were treated with chemotherapy at the University of Texas M. D. Anderson Cancer Center between 1978 and 2005. Response rates, progression‐free survival (PFS), and overall survival (OS) were compared between patients who received 5‐FU and a platinum compound and patients who received other chemotherapy combinations.

RESULTS.

The median patient age was 53 years. The primary tumor site was the jejunum in 35 patients (43%), duodenum in 30 patients (38%), ileum in 6 patients (8%), and nonspecified small bowel in 9 patients (11%). Of all 80 patients, 29 patients (36%) received 5‐FU and a platinum compound, 41 patients (51%) received 5‐FU without a platinum compound, and 10 patients (13%) received non‐5‐FU–based treatment. Compared with other chemotherapy regimens, treatment with 5‐FU and a platinum agent resulted in a higher response rate (46% vs 16% with other regimens; P = .01) and longer median PFS (8.7 months vs 3.9 months; P ≤ .01) but not better OS (14.8 months vs 12 months; P = .1). In multivariate analysis, treatment with 5‐FU and a platinum compound was a significant predictor of response (odds ratio, 4.5; 95% confidence interval [CI], 1.3‐15.8; P = .02) and PFS (hazard ratio. 0.49; 95% CI, 0.29‐0.84; P = .01) but only reached borderline significance for OS (hazard ratio, 0.63; 95% CI, 0.37‐1.07; P = .08).

CONCLUSIONS.

To the authors' knowledge, the current analysis represents the largest number of patients with metastatic SBA treated with chemotherapy in the literature, and the results suggested that the combination of 5‐FU and a platinum compound leads to a higher response rate and PFS compared with other chemotherapy regimes. The authors concluded that prospective investigation of platinum analogues in the treatment of SBA is warranted. Cancer 2008. © 2008 American Cancer Society.
Pyrenyl Excimers Induced by the Crystallization of POSS Moieties: Spectroscopic Studies and Sensing Applications
Authors: Bai Hua , Li Chun , Shi Gaoquan
Published: August 2008

An ester (PBPOSS) of 1‐pyrenebutyric acid (PBA) and 1‐(2,3‐propanediol)propoxy‐3,5,7,9,11,13,15‐isobutylpentacyclo‐[9.5.1.1(3,9).1(5,15).1(7,13)]octasiloxane (a polyhedral oligomeric silsesquioxane, POSS) is synthesized by simple one‐step esterification. Thin films of PBPOSS fabricated by the spin‐coating technique exhibit strong excimer emissions of visible light. Upon exposure to the vapours of nitroaromatic compounds, including trinitro‐ toluene and dinitrotoluene, the films show fast fluorescence quenching. The high performance of these gas sensors is due to the high excimer contents and good vapour permeability of the PBPOSS films. Spectroscopic studies indicate that the crystallization of the POSS moieties in PBPOSS films induce the formation of pyrenyl excimers.
Increased concentrations of soluble CD40 ligand may help to identify type 1 diabetic adolescents and young adults at risk for developing persistent microalbuminuria
Authors: Chiarelli F. , Giannini C. , Verrotti A. , Mezzetti A. , Mohn A.
Published: August 2008

Background

Recent studies on the pathogenesis of diabetic complications have demonstrated the important role of a number of aberrantly expressed molecules acting together in the development of early diabetic microvascular complications. Soluble CD40 ligand (sCD40L) is supposed to be one of the most likely candidates for both retinopathy and nephropathy.

Methods

In January 1989, sCD40L was measured in 340 normoalbuminuric diabetic adolescents and young adults. Participants were examined at baseline and biannually thereafter. sCD40L was measured every 2 years during a 16‐year follow‐up period. sCD40L was also measured in parents.

Results

Over 16 years, 32 out of 340 patients developed persistent microalbuminuria; no patient developed overt diabetic nephropathy. The risk of developing microalbuminuria was higher in children with increased sCD40L at the beginning of the study (using 6 ng/mL as the arbitrary cut‐off value) (group A) compared with those with normal sCD40L (group B). Sex did not influence predictive value, sensitivity, or specificity. sCD40L was not significantly correlated with duration of diabetes. The percentage of offspring with both parents having sCD40L above the mean values was significantly higher in group A than in group B. The odds ratio (OR) for the occurrence of microalbuminuria after adjustment for confounding variables in patients with elevated baseline sCD40L was 4.2 (95% CI, 2.1–10.7).

Conclusions

Persistently increased sCD40L levels from the onset of diabetes might help to identify those normotensive and normoalbuminuric young patients at increased risk of developing incipient nephropathy later in life. Copyright © 2008 John Wiley & Sons, Ltd.
A Theoretical Study on the Reactivity of a Rhenium Hydroxo‐Carbonyl Complex Towards β‐Lactams
Authors: Yeguas Violeta , Campomanes Pablo , López Ramón
Published: August 2008

The mechanism of the reaction between the complex [Re(OH)(CO)3(N2C2H4)] and azetidin‐2‐one or 3‐formylamino‐N‐sulfonatoazetidin‐2‐one was investigated by using the B3LYP density functional theory methodology in conjunction with the PCM‐UAHF model to take into account solvent effects. According to our calculations, the rate‐determining energy barrier for the azetidin‐2‐one case of 38.8 kcal mol−1, becomes 25.7 kcal mol−1 in the case of the 3‐formylamino‐N‐sulfonatoazetidin‐2‐one species. The presence of the sulfonato group is crucial for the cleavage of the β‐lactam N1–C2 bond by the Re complex thanks to the interaction of the sulfonato group with the hydroxy and bidentate ligands of the complex. This could be of interest for the synthesis of β‐amino acids and their derivatives from β‐lactams under mild conditions and in solvents of low polarity promoted by organometallic complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Ferrocene–Peptide Conjugate as a Hydrogenase Model System
Authors: de Hatten Xavier , Bothe Eberhardt , Merz Klaus , Huc Ivan , Metzler‐Nolte Nils
Published: August 2008

This work introduces a bis(cysteine) ligand to build a small peptidic model system of hydrogenase enzymes. Fe(C5H4CO–Cys–OMe)2 (LH2) has been employed as a chelate for an iron–carbonyl complex, which mimics two essential structural properties of the hydrogenase class of enzymes, namely the coordination of the iron–carbonyl core to peptide ligands and the presence of an electrochemical relay in spatial proximity. The treatment of LH2 with Fe3(CO)12 yields LFe2(CO)6 (3a), which is the first peptide‐coordinated iron hydrogenase active‐site model complex. Compound 3a was fully characterized spectroscopically (1H NMR, 13C NMR, IR and Mössbauer spectroscopy, mass spectrometry and elemental analysis). A single‐crystal X‐ray analysis confirms the proposed structure and reveals a staggered conformation of the Fe2(CO)6S2 core. Fourier transform infrared (FTIR) spectroelectrochemistry reveals an electronic interaction between the peptide backbone and the iron–carbonyl cluster, but not with the ferrocene subsite. The introduction of this peptidic cysteine‐based ligand into hydrogenase model chemistry helps to confirm the proposed cofactor biosynthesis and understand the electronic interplay between the metal–carbonyl active site and the protein environment in this important class of enzymes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Some biophysical properties of castor oil esterified with some acid anhydrides
Authors: Saied Mona A. , Mansour Samia H. , Eweis Mohamed , El‐Sabee Maher Z. , Saad Azima L. G. , Nour Kamal N. Abdel
Published: August 2008

A series of castor oil adducts were synthesized by esterification of castor oil with acid anhydrides: phthalic, maleic and succinic anhydrides. The chemical structure of castor oil and the prepared adducts were characterized by means of IR and 1H NMR spectroscopy. The number‐average and weight‐average molecular weights were measured by gel permeation chromatography. The electrical properties were studied through the permittivity, dielectric loss and conductivity measurements, which are considered to be in the range of electrical insulation. The electrical conductivity, which describes the ionic mobility of the systems, was found to be in the range of 10–9 to 10–12 S/cm. This indicates that castor oil and its esters could be used for antistatic applications. The viscosity η and the activation energy Eη, obtained from the dependency of viscosity on temperature using the Arrhenius equation, were found to increase with increasing molecular weight of the system. The effect of different concentrations of castor oil and its esters on the growth activities of the sugar beet pathogens R. solani and S. rolfsii was studied through the determination of percent germination, average length of hyphal extensions, dry mass yield and the production of sclerotia. The obtained data indicate that the esterification of castor oil with anhydrides improves the antifungal activity.
Kinetic study for the development of an accelerated oxidative stability test to estimate virgin olive oil potential shelf life
Authors: Mancebo‐Campos Vanessa , Fregapane Giuseppe , Desamparados Salvador María
Published: August 2008

This study proposes an accelerated test performed at mild temperature (40–60 °C) to measure oxidative stability and estimate the potential shelf life of extra‐virgin olive oil (EVOO). The kinetic behavior of normalized oxidation indices (PV, K232 and K270) and the oxidizing substrate [unsaturated fatty acids (UFA)] during storage of different virgin olive oil samples in darkness and at different temperatures (25–60 °C) is reported for the first time. PV and K232 followed an apparent pseudo zero‐order kinetics (R2 >0.951) at all the experimental temperatures in all samples, whereas the evolution of K270 apparently better fitted a pseudo first‐order kinetics (R2 >0.926). The temperature‐dependent kinetics of the oxidation indices and the UFA were well described by the linear Arrhenius equation between 25 and 60 °C (0.960< R2 <0.999, p <0.05). The best correlation between loss of PUFA and increase of oxidation product indices was K232 (0.581< R2 <0.924). The time required to reach the upper limits for PV, K232 and K270 established for the EVOO category in the current EU legislation correlated well with temperature using a potential equation, making it possible to set up an accelerated stability test at temperatures below 60 °C to estimate the potential shelf life under normal storage temperature conditions.
Electrochemical Determination of NDPhA via its Electrocatalysis at Porous Au Electrode in Room Temperature Ionic Liquid
Authors: Yang Hui‐Lin , Chu Guo‐Hai , Zhang Qian , Zhou Guo‐Jun , Li Jing‐Hong , Xia Xing‐Hua
Published: August 2008

N‐Nnitrosodiphenylamine (NDPhA) is a typical kind of nonvolatile nitrosamine. Its electrochemical oxidation occurs usually at relative positive potentials (>1.1 V) even at catalytic noble metal electrodes in aqueous solutions. The formation of oxide and evolution of oxygen at such high potentials makes the analysis of NDPhA on noble metal electrodes difficult. Accordingly, its electrochemical analysis is usually performed in anhydrous organic electrolytes. In this work, room temperature ionic liquid [BMIM+] [BF$\rm{ {_{4}^{-}}}$] acting as electrolyte was introduced in this electrochemical analysis systems. It acts as supporting electrolyte itself, has good solubility of organic compounds, and allows a wide performance potential window of noble electrode, and in turn, highly electrocatalytic noble electrode of platinum or gold can be used as working electrodes. After the investigation of the electrocatalytic behavior of NDPhA at a gold electrode in this room temperature ionic liquid electrolyte, high sensitive determination of NDPhA was designed. It is demonstrated that the electrochemical response of NDPhA is determined by a surface‐controlled process. Therefore, a sensor with high sensitivity was constructed by applying porous Au electrodes with highly electrocatalytic activity and large active surface area. The present approach on one hand broadens the application field of room temperature ionic liquids, and on the other hand provides a sensitive analytical method for environmental detection.
A Biomimetic Potentiometric Sensor Using Molecularly Imprinted Polymer for the Cetirizine Assay in Tablets and Biological Fluids
Authors: Javanbakht Mehran , Eynollahi Fard Solmaz , Abdouss Majid , Mohammadi Ali , Reza Ganjali Mohammad , Norouzi Parviz , Safaraliee Leila
Published: August 2008

Despite the increasing number of applications of molecularly imprinted polymers (MIPs) in analytical chemistry, the construction of a biomimetic potentiometric sensor remains still challenging. In this work, a biomimetic potentiometric sensor, based on a non‐covalent imprinted polymer was fabricated for the recognition and determination of cetirizine. The MIP was synthesized by precipitation polymerization, using cetirizine dihydrochloride as a template molecule, methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross linking agent. The sensor showed high selectivity and a sensitive response to the template in aqueous system. The MIP‐modified electrode exhibited Nernstian response (28.0±0.9 mV/decade) in a wide concentration range of 1.0×10−6 to 1.0×10−2 M with a lower detection limit of 7.0×10−7 M. The electrode has response time of ca. 20 s, high performance, high sensitivity, and good long term stability (more than 5 months). The method was satisfactory and used to the cetirizine assay in tablets and biological fluids.
Vertically Aligned CuO Nanowires Based Electrode for Amperometric Detection of Hydrogen Peroxide
Authors: Jia Wenzhao , Guo Min , Zheng Zhe , Yu Ting , Wang Ying , Rodriguez Edgar G. , Lei Yu
Published: August 2008

Vertically aligned copper oxide (CuO) nanowires were synthesized by directly heating copper foil on a hotplate under ambient conditions. The as‐grown CuO nanowires film is mechanically stable and was facilely attached to a glassy carbon (GC) electrode, offering an excellent electrochemical sensing platform. The CuO nanowires electrode shows excellent electrocatalytic response to H2O2 with significantly lower overpotentials for its oxidation and reduction and also exhibits a fast response and high sensitivity for the amperometric detection of H2O2. The novel vertically aligned CuO nanowires electrode is readily applicable to other analytes and has great potential applications in the electrochemical detection.
Amperometric Immunosensor for the Determination of α‐1‐Fetoprotein Based on Core‐Shell‐Shell Prussian Blue‐BSA‐Nanogold Functionalized Interface
Authors: Hong Chenglin , Yuan Ruo , Chai Yaqin , Zhuo Ying
Published: August 2008

In the present work, a newly functional nanoparticle has been prepared to immobilize the protein for the detection of α‐1‐fetoprotein (AFP). Prussian blue (PB) nanoparticle was initially synthesized under ultrasonic condition, then bovine serum albumin (BSA) was used to coat the PB nanoparticle to improve the stability of the PB nanoparticle as well as functionalize the surface of PB nanoparticle, and then gold colloids were loaded on the BSA‐coated PB nanoparticle to construct a core‐shell‐shell nanostructure via the conjunction of thiolate linkages or alkylamines of the BSA. Finally, a convenient, effective and sensitivity amperometric immunosensor for the detection of α‐1‐fetoprotein (AFP) was constructed by the employment of these functional core‐shell‐shell microspheres. The preparation of the nanoparticle (Au‐BSA‐PB NPs) was characterized by transmission electron microscopy (TEM), and the assembly of the biosensor was characterized with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The dynamic range of the resulted immunosensor for the detection of AFP is from 0.02 ng/mL to 200.0 ng/mL with a detection limit of 0.006 ng/mL (S/N=3). Moreover, this biosensor displays good selectivity, stability and reproducibility.
Electrocatalytic Oxidation of Glucose at Carbon Nanotubes Supported PtRu Nanoparticles and Its Detection
Authors: Li Li‐Hua , Zhang Wei‐De , Ye Jian‐Shan
Published: August 2008

PtRu nanoparticles were supported on multiwall carbon nanotubes (MWNTs), which were further fabricated as an electrode for nonenzymatic glucose sensing. Transmission electron microscope and X‐ray diffraction patterns were used for characterization of the PtRu nanoparticles on MWNTs. Cyclic voltammetry and chronopotentiometry were applied to investigate the performance of the PtRu/MWNTs nanocomposite electrode for nonenzymatic oxidation of glucose. The PtRu/MWNTs electrode shows high electrocatalytic activity towards the oxidation of glucose in 0.1 M NaOH solution and thus can be used to selectively detect glucose. Under the optimal potential (+0.55 V vs. Ag/AgCl), the biosensor effectively performs a selective electrochemical analysis of glucose in the presence of common interferents, such as ascorbic acid (AA), dopamine (DP) and uric acid (UA). Wide linear calibration ranging from 1 mM to 15 mM, high sensitivity of 28.26 μA cm−2 mM−1, low detection limit of 2.5×10−5 M, and fast response time of 10 s were achieved for the detection of glucose at the PtRu/MWNTs electrode.
A Glucose Biosensor Based on Immobilization of Glucose Oxidase into 3D Macroporous TiO2
Authors: Cao Huimin , Zhu Yihua , Tang Longhua , Yang Xiaoling , Li Chunzhong
Published: August 2008

3D macroporous TiO2 inverse opals have been derived from a sol‐gel procedure using polystyrene colloidal crystals as templates. EDS and SEM showed a face‐centered cubic (FCC) structure TiO2 inverse opal was obtained. Glucose oxidase (GOx) was successfully immobilized on the surface of indium‐tin oxide (ITO) electrode modified by TiO2 inverse opal (TiO2(IO)). Electrochemical properties of GOx/TiO2(IO)/ITO electrode were characterized by using the three electrodes system. The result of cyclic voltammetry showed that a couple of stable and well‐defined redox peaks for the direct electron transfer of GOx in absence of glucose, and the redox peak height enhanced in presence of 0.1 μM glucose. Compare with the ordinary structured GOx/TiO2/ITO electrode, inverse opal structured GOx/TiO2(IO)/ITO electrode has a better respond to the glucose concentration change. Under optimized experimental conditions of solution pH 6.8 and detection potential at 0.30 V versus saturated calomel electrode (SCE), amperometric measurements were performed. The sensitivity and the detection limit of glucose detection was 151 μA cm−2 mM−1 and 0.02 μM at a signal‐to‐noise ratio of 3, respectively. The good response was due to the good biocompatibility of TiO2 and the large effective surface of the three‐dimensionally ordered macroporous structure.
Die Gattung Ilex L. (Aquifoliaceae) im Paläogen von Mitteleuropa
Authors: Walther Harald , Kvaček Zlatko
Published: August 2008

Die Gattung Ilex L. stellt im Paläogen (Unter‐ und Oberoligozän) Mitteleuropas ein wichtiges Akzessorium in der Waldvegetation (Mixed Mesophytic Forests) dar. Sie wird häufiger durch karpologische Belege seltener durch Blattreste nachgewiesen. Die Morphospecies lassen sich mit immergrünen rezenten Vertretern aus den miteinander verwandten Sektionen Ilex und Lioprinus Loes. der Gattung Ilex L. vergleichen. Die untersuchten fossilen Ilex ‐Blätter wurden zu Ilex castellii Kvaček & Walther gestellt. Diese Morphospecies ist aus dem paläogenen Florenkomplex Seifhennersdorf–Kundratice (32,7 bis 29,5 Millionen Jahre, Kvaček & Walther 2001) wie Kundratice (Nordböhmen) und Hammerunterwiesenthal (Sachsen), wie aus dem Florenkomplex Flörsheim–Nerchau (Mai 1995), wie Malá Veleň und Levínské Petrovice, Nordböhmen bekannt. Aus dem Fundort Hammerunterwiesenthal wurden sie erstmalig in Turbiditen aus einer unreifen Maarfüllung in räumlicher Erhaltung nachgewiesen. Das bisher südlichste Vorkommen dieser Art stammt aus dem Braunkohlenbecken von Trbovlje (Trifail) Slovenien – Florenkomplex Kiscell (Kvaček & Walther 2001), Unteroligozän. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Buxus‐ (Buxaceen) Pollenformen aus alttertiären Ablagerungen Mitteleuropas und ihre paläochorologische Bedeutung
Authors: Krutzsch Wilfried
Published: August 2008

Es werden sechs Grundtypen von fossilen „buxoiden”︁ Pollenformen behandelt; vier von ihnen sind Neubeschreibungen (Irregularispollis, gen. nov. et sp. nova,Transmorphopollis, gen. nov. et sp. nova,Tritricolporopollis, gen. nov. et sp. nova undPentatricolporopollis, gen. nov. et sp. nova), eine der beiden schon bestehenden Pollengattungen wird emendiert(Nagyipollis). Auf die bisher vor allem im Alttertiär Mitteleuropas ermittelte Formenfülle wird hingewiesen und ihre Verbreitung in zeitlicher und räumlicher Hinsicht wird diskutiert, dabei wird auf eine Reihe wichtiger bisheriger Fossilhinweise der Literatur kritisch eingegangen. Die fossilen „buxoiden”︁ Pollenformen werden den jeweiligen rezenten Vertretern, d.h. den bestehenden (bisherigen) subgenera bzw. den entsprechenden Pollen‐Morphotypen zugeordnet. Die GattungBuxusinsgesamt wird einem kurzen paläochorologischen Diskurs unterzogen, wobei auch die Stellung der gesamten Familie Buxaceen in Hinblick auf die Differentiation der Pollenformen mit einbezogen wird, inklusive der Hinweise auf noch ältere oberkretazische Pollenausbildungen. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bemerkungen zuMetasequoiaMiki ex Hu & Cheng und persönliche Erinnerungen an Werner Rothmaler
Authors: Daber Rudolf
Published: August 2008

Die Mikrosporophylle vonMetasequoia glyptostroboidesHu & Cheng sind peltat und tragen vier gelbe Pollensäcke, die am unteren Rand des sehr dünnen Sporophylls angeheftet sind. Intensiv grün gefärbte Zellen kennzeichnen den mittleren Teil des sonst völlig farblosen Sporophylls – offenbar steuert diese Assimilationstätigkeit die kurze Zeit des Frühjahrswachstums des fertilen Teils des Sporophyllzapfens. Dieser wird üblicherweise nur in ovaler Form abgebildet und beschrieben, ist aber ausgereift schließlich lang gestreckt. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Die Ackerbohne (Vicia fabaL.) in Mitteleuropa als Kulturpflanze seit der späten Bronzezeit
Authors: Jäger Klaus‐Dieter
Published: August 2008

Ein wesentlicher Teil der umfangreichen Bemühungen von Werner Rothmaler um die Reaktivierung botanischer Forschungen in Deutschland nach dem II. Weltkrieg zielte auf Fortführung und Wiederbelebung paläoethnobotanischer Untersuchungen. Besonderes Interesse galt dabei dem Altbestand an mitteleuropäischen Kulturpflanzen mit Anbautradition seit dem Neolithikum.

Als spätere Einbürgerung fiel dabei die Ackerbohne (Vicia fabaL.) auf, die das Spektrum seit der Bronzezeit erweitert.

Eine Neukartierung datierter Fundortnachweise belegt und präzisiert diese Datierung und erlaubt Erörterung über Ursachen und Besonderheiten der Ausbreitungsgeschichte (Urnenfelderbewegung der späten Bronzezeit im Subboreal). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Auf dem Weg zu einer Monographie der Gattung Alchemilla L. (Rosaceae)
Authors: Fröhner Sigurd E.
Published: August 2008

Werner Rothmaler hat als Erster auf eine Monographie der Gattung Alchemilla hingearbeitet. Die Weiterführung des abgebrochenen Weges wird an den wichtigsten Publikationen der folgenden Zeit dargestellt. Auf retardierende Elemente in der fortschreitenden Beschäftigung mit der Gattung, gar Widersprüche, wird besonders hingewiesen – als Chance zu vertiefter Einsicht. Es folgen Überlegungen über Inhalt und Vielseitigkeit einer Monographie. Besonderer Wert wird auf genau und hilfreich erarbeitete Bestimmungsschlüssel und verantwortungsvolle Kartierungsarbeit gelegt. Als hohes Ziel wird die Erhaltung der Gattung in der Natur dargestellt. Die Aussichten, heute auf eine Monographie der Gattung hinzusteuern, werden skeptisch bewertet. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atriplex praecox Hülph. und Atriplex longipes Drejer (Chenopodiaceae) in morphologischer Betrachtung
Authors: Krisch Haubold
Published: August 2008

Atriplex praecox, entdeckt an der vorpommerschen Boddenküste (Ostsee), wird verglichen mit Atriplex longipes. Der Bauplan beider Arten wird bestimmt von einem Unterbau mit Verzweigung und dekussierter Beblätterung an den ersten vier Knoten sowie durch eine Übergangszone mit Auflösung der zweigliedrigen Wirtel und disperser Beblätterung. Diese subflorale Zone ist mit vier Blättern gut entwickelt bei A. longipes, bei A. praecox aber kann sie fehlen. Viele Beisprosse, reduziert zu einblütigen Scheinblüten mit großen, laubblattähnlichen Vorblättern, kennzeichnen A. longipes, spielen aber für A. praecox keine Rolle. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Durable and rechargeable biocidal polypropylene polymers and fibers prepared by using reactive extrusion
Authors: Badrossamay Mohammad Reza , Sun Gang
Published: August 2008

Incorporation of N‐halamine precursor onto polypropylene was explored by using a reactive extrusion process. Several cyclic and acyclic halamine precursors were grafted onto polypropylene backbone through a melt free radical graft copolymerization. The structures and morphology of the grafted polymer were characterized with FTIR, and scanning electron microscope. Thermal properties of the polymers were evaluated by differential scanning calorimetry. The halogenated products of the corresponding grafted samples exhibited potent antimicrobial properties against Escherichia coli, and the antimicrobial properties were durable and regenerable. The relationship between effective surface contact and biocidal efficacy are further discussed. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
CD38 is constitutively expressed in the nucleus of human hematopoietic cells
Authors: Orciani M. , Trubiani O. , Guarnieri S. , Ferrero E. , Di Primio R.
Published: August 2008

CD38 is a type II glycoprotein that acts both as a bifunctional enzyme, responsible for the synthesis and hydrolysis of cyclic ADP‐ribose, and as a signal‐transducing surface receptor. Although CD38 was originally described as a plasma membrane molecule, several reports indicate that CD38 is expressed in the nucleus, even in cells known to be CD38 surface‐negative. In this study, firstly we investigated the presence of nuclear CD38 by immunofluorescence and confocal microscopy using a panel of hematopoietic cell lines that exhibit different levels of CD38 plasma membrane expression. Our second aim was to explore the relationship between the nuclear and plasma membrane forms of CD38 in human cell lines which represent discrete early maturation stages of the human lymphoid and myeloid compartments. Our results indicate that CD38 is constitutively present in the nucleus of cells belonging to distinct lineages. Furthermore, nuclear CD38 appears to be independent of the plasma membrane pool. The presence of nuclear CD38 during different stages of hematopoietic differentiation suggests that it may play a role in the control of nuclear Ca2+ homeostasis and NAD levels. J. Cell. Biochem. 105: 905–912, 2008. © 2008 Wiley‐Liss, Inc.
Weight choosability of graphs
Authors: Bartnicki Tomasz , Grytczuk Jarosław , Niwczyk Stanisław
Published: August 2008

Suppose the edges of a graph G are assigned 3‐element lists of real weights. Is it possible to choose a weight for each edge from its list so that the sums of weights around adjacent vertices were different? We prove that the answer is positive for several classes of graphs, including complete graphs, complete bipartite graphs, and trees (except K2). The argument is algebraic and uses permanents of matrices and Combinatorial Nullstellensatz. We also consider a directed version of the problem. We prove by an elementary argument that for digraphs the answer to the above question is positive even with lists of size two. © 2008 Wiley Periodicals, Inc. J Graph Theory 60: 242–256, 2009
Endophytic population of Pantoea agglomerans in citrus plants and development of a cloning vector for endophytes
Authors: Andreote Fernando D. , Rossetto Priscilla B. , Souza Leonardo C. A. , Marcon Joelma , Maccheroni Walter , Azevedo João L. , Araújo Welington L.
Published: August 2008

Harmless bacteria inhabiting inner plant tissues are termed endophytes. Population fluctuations in the endophytic bacterium Pantoea agglomerans associated with two species of field cultured citrus plants were monitored over a two‐year period. The results demonstrated that populations of P. agglomerans fluctuated in Citrus reticulata but not C. sinensis. A cryptic plasmid pPA3.0 (2.9 kb) was identified in 35 out of 44 endophytic isolates of P. agglomerans and was subsequently sequenced. The origins of replication were identified and nine out of 18 open reading frames (ORFs) revealed homology with described proteins. Notably, two ORFs were related to cellular transport systems and plasmid maintenance. Plasmid pPA3.0 was cloned and the gfp gene inserted to generate the pPAGFP vector. The vector was introduced into P. agglomerans isolates and revealed stability was dependent on the isolate genotype, ninety‐percent stability values were reached after 60 hours of bacterial cultivation in most evaluated isolates. In order to definitively establish P. agglomerans as an endophyte, the non‐transformed bacterium was reintroduced into in vitro cultivated seedlings and the density of inner tissue colonization in inoculated plants was estimated by bacterium re‐isolation, while the tissue niches preferred by the bacterium were investigated by scanning electronic microscopy (SEM). Cells from P. agglomerans (strain ARB18) at similar densities were re‐isolated from roots, stems and leaves and colonization of parenchyma and xylem tissues were observed. Data suggested that P. agglomerans is a ubiquitous citrus endophyte harboring cryptic plasmids. These characteristics suggest the potential to use the bacterium as a vehicle to introduce new genes in host plants via endophytic bacterial transformation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of extracellular elastase, acid proteinase and phospholipase activities as putative virulence factors in clinical isolates of Aspergillus species
Authors: Alp Sehnaz , Arikan Sevtap
Published: August 2008

We investigated the production of extracellular elastase, acid proteinase and phospholipase enzyme activities in clinical isolates of Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger and any possible correlation between the existence of these enzymes and development of invasive aspergillosis. A total of 73 strains (45 A. fumigatus, 23 A. flavus, 5 A. niger) isolated from patients with invasive aspergillosis (n = 55), superficial aspergillosis (n = 5), allergic bronchopulmonary aspergillosis (n = 1), and from those colonized with Aspergillus (n = 12) were included in the study. The enzymatic activities were tested on solid media supplemented with the corresponding substrates. Elastase activity was detected in 95.6, 82.6, and 0% of A. fumigatus, A. flavus, and A. niger isolates, respectively. Acid proteinase activity was detected only for A. fumigatus and in 20 of 45 isolates belonging to this species. Phospholipase activity was present in all strains of A. fumigatus and A. niger but in none of the isolates of A. flavus. No statistical correlation could be established between the existence of elastase or acid proteinase activity and development of invasive disease (p > 0.05). While high phospholipase production was found to be associated with development of invasive aspergillosis (p < 0.01), not all isolates that caused invasive diseases showed high phospholipase activities. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of a defined medium for heterologous expression in Leishmania tarentolae
Authors: Fritsche Claudia , Sitz Mandy , Wolf Marco , Pohl Hans‐Dieter
Published: August 2008

A defined medium is essential for studying nutritional requirements of microorganisms and for selective supplementation of necessary substances. Hemin is an essential ingredient for growth of Leishmania tarentolae, but tends to precipitate in aqueous solutions without further stabilization. These aggregates disturb the measurement of the optical density or the cell density and the following downstream processing. Therefore, we were looking for stabilizing substances and established a PEG‐hemin‐solution, which avoided flocculation and allowed the cultivation of L. tarentolae in a medium, which we termed SFP(II) medium. With addition of RNA from Saccharomyces cerevisiae to SFP(II) medium the SFP(III) medium was established. In this medium, the specific cell division rate was increased (0.103 h–1) and stable for longer periods of time. The evaluation of the SFP(III) medium was done in shaker flasks by successful expression and segregation of the SAG2 protein, one of the main surface antigens of Toxoplasma gondii. With establishment and evaluation of this defined medium, the status of the Leishmania tarentolae expression system as an alternative to commonly used cell cultures is supported. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)