bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of vibration treatment on tibial bone of ovariectomized rats analyzed by in vivo micro‐CT
Authors: Brouwers Julienne E.M. , van Rietbergen Bert , Ito Keita , Huiskes Rik
Published: July 2009

Daily low‐amplitude, high‐frequency whole‐body vibration (WBV) treatment can increase bone formation rates and bone volume in rodents. Its effects vary, however, with vibration characteristics and study design, and effects on 3D bone microstructure of ovariectomized animals over time have not been documented. Our goal was to determine the effects of WBV on tibial bone of ovariectomized, mature rats over time using an in vivo micro‐CT scanner. Adult rats were divided into: ovariectomy (OVX) (n = 8), SHAM‐OVX (n = 8), OVX and WBV treatment (n = 7). Eight weeks after OVX, rats in the vibration group were placed on a vibrating platform for 20 min at 0.3 g and 90 Hertz. This was done 5 days a week for six weeks, twice a day. Zero, 8, 10, 12 and 14 weeks after OVX, in vivo micro‐CT scans were made (vivaCT 40, Scanco Medical AG) of the proximal and diaphyseal tibia. After sacrifice, all tibiae were dissected and tested in three‐point bending. In the metaphysis between 8 to 12 weeks after OVX, WBV treatment did not alter structural parameters compared to the OVX group and both groups continued to show deterioration of bone structure. In the epiphysis, structural parameters were not altered. WBV also did not affect cortical bone and its bending properties. To summarize, no substantial effects of 6 weeks of low‐magnitude, high‐frequency vibration treatment on tibial bone microstructure and strength in ovariectomized rats were found. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:62–69, 2010
Synthetic polycation: Polynucleotide interactions determined using liquid chromatography with short monolithic columns
Authors: Platonova Galina A. , Nazarova Olga V. , Tennikova Tatiana B.
Published: July 2009

LC on short monolithic columns (Convective Interaction Medium Disks) was applied to investigate several specially synthesized water soluble polycations of different charge type (primary, tertiary, quaternary amine), as well as a copolymer of neutral saccharide and cationic monomers, regarding their ability to form reversible complexes with DNA. For this purpose, two separation modes were used, namely, pseudo‐affinity and cation‐exchange chromatography. Synthetic polynucleotides, namely, polyriboadenylic acid (poly(rA)) and polyribocytidylic acid (poly(rC)), were used as approximate structural analogues of DNA. In first case, the hypothetical specific binding between dissolved polymers and polynucleotide (poly(rA) or poly(rC)), covalently attached to epoxy‐bearing monolithic sorbent, has been studied and compared to the results obtained using cation exchange chromatography. Quantitative parameters of interactions between macromolecules were established using frontal elution method.
Islamic tourism and managing tourism development in Islamic societies: the cases of Iran and Saudi Arabia
Authors: Zamani‐Farahani Hamira , Henderson Joan C.
Published: July 2009

This paper is concerned with the effects of state religion on tourism development in Muslim countries with particular reference to Iran and Saudi Arabia. Aspects of the relationship between Islam and tourism are investigated overall and issues of tourism policies, management and marketing and community involvement within the context of the two cases are discussed. The distinctive circumstances prevailing in Iran and Saudi Arabia are suggested, but more general insights are also presented into the interactions between and management of tourism and Islam. Copyright © 2009 John Wiley & Sons, Ltd.
Interdisciplinary and multidisciplinary approaches to the study of long‐term soil degradation: A case study from Schleswig‐Holstein, Germany
Authors: Emadodin I. , Reiss S. , Mitusov A. V. , Bork H. R.
Published: July 2009

Soil degradation is a serious problem and an important environmental issue in many ecosystems. Without integrative, interdisciplinary and historical approaches, understanding the effects of long‐term soil degradation is difficult. According to this idea it is hypothesized that in order to study long‐term natural and human‐induced soil degradation, it is necessary to use interdisciplinary and multidisciplinary approaches with respect to temporal and spatial landscape changes. The results of the investigation of colluvial sediments and soils in research area in Schleswig‐Holstein (Germany) with a high resolution in space and time—using the four‐dimensional landscape analysis—indicated the temporal and spatial variation of soils and sediments from the Mesolithic until Modern times. Intensive soil degradation occurred as a result of the land clearance and agricultural land use in the investigation areas since the Neolithic time. The general results of this investigation show that the use of an interdisciplinary and multidisciplinary approach with pedological and geomorphological perspectives for different times and places can help to reconstruct the long‐term natural and human‐induced soil degradation. Copyright © 2009 John Wiley & Sons, Ltd.
Hyperbranched Polyamidoamines Containing β‐Cyclodextrin for Controlled Release of Chlorambucil
Authors: Zhou Yuanyuan , Guo Zhe , Zhang Yongwen , Huang Wei , Zhou Yongfeng , Yan Deyue
Published: July 2009

This work is focused on the controlled drug release behavior of hyperbranched HPMA in the presence of β‐CD. Hence, three HPMA‐β‐CDs and a pure HPMA were synthesized by Michael addition polymerization. As a model drug, CLB (an anti‐cancer drug) was loaded into them via a solution method for in vitro release studies. The DSC results indicate that the CLB/polymer interactions are at the molecular level. Loading CLB into these polymers results in an evident increase in their glass transition temperatures, and ΔTg depends on the β‐CD content. The controlled‐release experiments show that the presence of β‐CD can appropriately slow the release of CLB from HPMA‐β‐CDs and adjust the ratio of CLB released in total drug loading.

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Cationic Conjugated Polymer/Heparin Interpolyelectrolyte Complexes for Heparin Quantification
Authors: Shi Jianbing , Pu Kan‐Yi , Zhan Ruoyu , Liu Bin
Published: July 2009

A cationic conjugated polymer (P1) containing 20 mol‐% 2,1,3‐benzothiadiazole (BT) content is synthesized through a post‐polymerization method. With a good water solubility (≈20 mg · mL−1), this polymer has shown a low inherent BT emission in aqueous solution. Formation of interpolyelectrolyte complexes between oppositely charged P1 and heparin facilitates energy transfer from the fluorene segments to the BT units within P1, leading to the intensity increase for the orange emission peak at 585 nm and the intensity decrease for the blue emission at 412 nm. A practical calibration curve ranging from 0.2 to 76 × 10−6 M is thus obtained by correlating the changes in BT emission with the heparin concentration in buffer. The significant advantage of this heparin macromolecular probe is that the calibration curve could cover the whole range of the therapeutic dosing level of heparin.

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On the Interrelationship of Transreactions with Thermal Properties and Dynamic Mechanical Analysis of PTT/PEN Blends
Authors: Jafari Seyed‐Hassan , Khonakdar Hossein Ali , Asadinezhad Ahmad , Häußler Liane , Böhme Frank , Komber Hartmut
Published: July 2009

An attempt was made to explore the effects of interchange reactions on the crystallization, melting, and dynamic mechanical behavior of binary blends based on poly(trimethylene terephthalate) (PTT)/poly(ethylene 2,6‐naphthalate) (PEN). 1H NMR spectroscopy is used to verify the occurrence of interchange reactions at the interface, which are increased upon an increase in the melt processing time and temperature. The crystallinity of PTT was reduced while that of PEN was increased on blending. In addition, the crystallization temperatures of both phases showed depression. A single composition‐dependent glass transition temperature (Tg) was detected in the second and subsequent heating thermograms of the blends, which is indicative of miscibility. The cold crystallization of the PTT phase was observed to increase while that of PEN was suppressed on blending. Each phase crystallized individually and a melting point depression was evident, which suggests a certain level of miscibility. Dynamic mechanical thermal analysis corroborated differential scanning calorimetry results. A constructive synergism was observed in the glassy state storage moduli of the blends, which is suggestive of a reduced specific volume of the system because of enhanced interactions and crystallinity.

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Metathesis with Oleochemicals: New Approaches for the Utilization of Plant Oils as Renewable Resources in Polymer Science
Authors: Meier Michael A. R.
Published: July 2009

Due to depleting fossil resources, the ever increasing emission of greenhouse gases and toxic waste, as well as the inefficient utilization of our available resources, we have to implement the principles of green chemistry whenever and wherever possible. Plant oils are already the most important renewable resource for the chemical industry. Due to their inherent double‐bond functionality, they offer the possibility of being transformed via several very efficient catalytic processes. Especially, new developments in olefin metathesis allow the chemist to directly polymerize or introduce a variety of functional groups to these renewable resources in an efficient manner. Therefore, olefin metathesis with plant‐oil‐derived fatty acids and their derivatives can contribute to a sustainable development of our future, since this approach has great potential for the substitution of currently used petrochemicals and a variety of value‐added chemical intermediates, especially for the polymer industry, can be derived from these resources in a straightforward fashion. This contribution will address and discuss the most recent developments in this field of research.

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Dynamic Monte Carlo Simulation of ATRP in a Batch Reactor
Authors: Al‐Harthi Mamdouh A. , Masihullah Jabarullah K. , Abbasi Sarfraz H. , Soares João B. P.
Published: July 2009

A dynamic MC model was developed to simulate the polymerization kinetics and the detailed microstructure of copolymers made with ATRP in a batch reactor. The model was used to predict monomer conversion, average molecular weight, polydispersity index, and copolymer composition as a function of polymerization time. The model can also predict the distribution of molecular weight, chemical composition, and comonomer sequence length at any polymerization time or comonomer conversion. The simulation was used to explore the effects of rate constants and reactant stoichiometry on the microstructure of chains. Two copolymerization systems were chosen to demonstrate the effect of reactivity ratios and comonomer feed compositions on the final chemical composition distribution.

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PI3K signaling maintains c‐myc expression to regulate transcription of E2F1 in pancreatic cancer cells
Authors: Schild Carolin , Wirth Matthias , Reichert Maximilian , Schmid Roland M. , Saur Dieter , Schneider Günter
Published: July 2009

Phosphatidylinositol 3‐kinase (PI3K) signaling controls survival and proliferation of cancer cells and is activated in around 60% of pancreatic ductal adenocarcinomas (PDACs). Although not entirely clarified, PI3K signaling is linked to cell cycle progression of PDAC cells. In this study we demonstrate that PI3K signaling controls transcription of the E2F1 gene and show that E2F1 is essential for S‐phase progression of PDAC cells. On the molecular level, PI3K signaling controls c‐myc protein abundance in a glycogen synthase kinase‐3 (GSK3)‐dependent fashion. c‐myc binds to the E‐box of the E2F1 gene in PDAC cells and this binding is under control of the PI3K‐signaling pathway. Together, we demonstrate that PI3K–GSK3‐dependent control of c‐myc protein expression is connected to the transcription of the E2F1 gene in PDAC cells, leading to S‐phase progression of the cell cycle. © 2009 Wiley‐Liss, Inc.
Effects of food processing on food allergens
Authors: Sathe Shridhar K. , Sharma Girdhari M.
Published: July 2009

Food allergies are on the rise in Western countries. With the food allergen labeling requirements in the US and EU, there is an interest in learning how food processing affects food allergens. Numerous foods are processed in different ways at home, in institutional settings, and in industry. Depending on the processing method and the food, partial or complete removal of the offending allergen may be possible as illustrated by reduction of peanut allergen in vitro IgE immunoreactivity upon soaking and blanching treatments. When the allergen is discretely located in a food, one may physically separate and remove it from the food. For example, lye peeling has been reported to produce hypoallergenic peach nectar. Protein denaturation and/or hydrolysis during food processing can be used to produce hypoallergenic products. This paper provides a short overview of basic principles of food processing followed by examples of their effects on food allergen stability. Reviewed literature suggests assessment of processing effects on clinically relevant reactivity of food allergens is warranted.
Quantum chemistry investigation of electronic structure and NMR spectral characteristics for fluorides of dialkylamidosulfoxylic acids and related compounds
Authors: Rozhenko A. B. , Schoeller W. W. , Kozel V. N. , Pashinnik V. E. , Shermolovich Yu. G.
Published: July 2009

The parent (H2NSF) and N,N‐dialkyl‐substituted fluorides of amidosulfoxylic acid (R2NSF, RMe or R2NMorph) as well as the related compounds XSF (XCH3, OH, F, SiH3, PH2, SH, Cl) have been investigated with quantum chemical calculations at the ab initio (MP2) level of approximation. The geometries, electronic structures, molecular orbital (MO) energies and NMR chemical shift values have been calculated to evaluate the role and extent of the polarization and delocalization effects in forming of the high‐field fluorine NMR resonances within the series of interest. The δF magnitudes for all investigated fluorides of amidosulfoxylic acid as well as the δN value calculated for Me2NSF are in the good agreement with the 19F and 14N NMR chemical shift values measured experimentally. For the parent compounds, H2NSF and H2NSO2F, the orientation of principal axes of the magnetic shielding tensors and the corresponding principal σii values along these axes have been qualitatively interpreted basing on the analysis of the MO interactions in the presence of the rotating magnetic field. Copyright © 2009 John Wiley & Sons, Ltd.
Composites of poly (dimethylsiloxane) and spherically shaped poly (2‐hydroxyethylmethacrylate) particles for biomedical use
Authors: Tang Qi , Yu Jun‐Rong , Chen Lei , Zhu Jing , Hu Zu‐Ming
Published: July 2009

Silicone rubbers have shown considerable promise in the biomedical field, but their hydrophobicity leads to serious problems in long‐term implants. In our study, composites of poly (dimethylsiloxane) (PDMS) and spherically shaped poly (2‐hydroxyethylmethacrylate) (PHEMA) microparticles were prepared. Unlike previous silicone hydrogel composites, suspension polymerization was carried out in an aqueous medium to prepare PHEMA particles directly, which avoided the removal of organic phase and give hydrogel particles with high purity. Very fine PHEMA particles with uniform geometry and small size were obtained through various influencing factors during their formation. Through the introduction of PHEMA particles, PDMS matrix was endowed with hydrophilicity to a certain extent. With an increase in hydrogel content, higher swelling ability and surface wettability of the composites were observed. We have also demonstrated that smaller sized particles are more favorable for hydrophilicity improvement. The results of improved swelling ability, surface wettability, and low affinity to lipid show that this composite material is suitable for biomedical use. Copyright © 2009 John Wiley & Sons, Ltd.
Tid1 functions as a tumour suppressor in head and neck squamous cell carcinoma
Authors: Chen Chi‐Yuan , Chiou Shih‐Hwa , Huang Chih‐Yang , Jan Chia‐Ing , Lin Shu‐Chun , Hu Wen‐Yuan , Chou Shiu‐Huey , Liu Chung‐Ji , Lo Jeng‐Fan
Published: July 2009

Human tumourous imaginal disc (Tid1), a human homologue of the Drosophila tumour suppressor protein Tid56, is involved in multiple intracellular signalling pathways such as apoptosis, cell proliferation, and cell survival. Here, we investigated the anti‐tumourigenic activity of Tid1 in head and neck squamous cell carcinoma (HNSCC) in vitro and in vivo. Firstly, the clinical association between Tid1 expression and progression of HNSCC was explored. It was found that expression of Tid1 was negatively associated with tumour status, recurrence, and survival prognosis using immunohistochemical analysis of primary HNSCC patient tumour tissue. Secondly, ectopic expression of Tid1 in HNSCC cells was shown to significantly inhibit cell proliferation, migration, invasion, anchorage‐independent growth, and xenotransplantation tumourigenicity. Thirdly, we showed that overexpression of Tid1 attenuated EGFR activity and blocked the activation of AKT in HNSCC cells, which are known to be involved in the regulation of survival in HNSCC cells. On the other hand, ectopic expression of constitutively active AKT greatly reduced apoptosis induced by Tid1 overexpression. Together, these findings suggest that Tid1 functions as a tumour suppressor in HNSCC tumourigenesis. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis of right aortic arch: associated findings, pregnancy outcome, and clinical significance of vascular rings
Authors: Galindo A. , Nieto O. , Nieto M. T. , Rodríguez‐Martín M. O. , Herraiz I. , Escribano D. , Granados M. A.
Published: July 2009

Objectives

To analyze the characteristics and clinical implications of right aortic arch (RAA) detected in fetal life.

Methods

Retrospective study of all cases of RAA diagnosed prenatally in high‐risk patients who underwent fetal echocardiography between 2000 and 2007.

Results

There were 48 RAA; 18 had vascular ring (Group 1), including 15 RAA with aberrant left subclavian artery and 3 double aortic arch, and 30 had not vascular ring (Group 2), all RAA with mirror‐image branching. The prenatal diagnosis was confirmed in 94%. In Group 1 most fetuses had normal heart (89%), and none had 22q11 deletion. There were 16 live births and all infants but one are asymptomatic (mean follow‐up of 31 months). In Group 2 almost all fetuses had congenital heart defects (CHDs) (97%), and five were chromosomally abnormal (17%), including four 22q11 deleted. The 1‐year survival rate was 69%, which was significantly higher in Group 1 (89% vs 57%, p < 0.05).

Conclusions

RAA can be accurately diagnosed by fetal echocardiography. The outlook for these patients largely depends on the presence of associated defects, mainly CHDs, and their severity. If isolated, aortic arch anomalies are asymptomatic vascular variants in most cases. This information is important to assist parental counseling in pregnancy. Copyright © 2009 John Wiley & Sons, Ltd.
The clinical significance of co‐morbid post‐traumatic stress disorder and borderline personality disorder: Case study and literature review
Authors: Vignarajah Biruthvie , Links Paul S.
Published: July 2009

The purpose of this study is to determine the clinical significance of co‐morbid borderline personality disorder (BPD) and post‐traumatic stress disorder (PTSD), and the effect of this co‐morbidity on suicidal behaviour and response to treatment. Review of the evidence from past studies revealed that, although an additional diagnosis of PTSD did not exacerbate the BPD condition (or vice versa), certain symptoms were accentuated. These symptoms included anger, anxiety and avoidant behaviours as well as suicide proneness. The case analysed for the purposes of this study also highlights these findings from the literature review (i.e. certain symptoms of both PTSD and BPD were exacerbated in the patient, but there was no increase in overall psychopathology). The literature review further shows that despite promising results of alleviation of certain BPD features when treating for PTSD, treatment of such a co‐morbid condition must proceed with caution as treatment of PTSD without treatment of BPD and the related suicidal behaviour may be detrimental to the patient. Copyright © 2009 John Wiley & Sons, Ltd.
First degree relatives of women with breast cancer: who's providing information and support and who'd they prefer
Authors: Tunin Rina , Uziely Beatrice , Woloski‐Wruble Anna C.
Published: July 2009

Introduction: Mothers, sisters, and daughters of women diagnosed with breast cancer have an increased need for factual information, counseling, and emotional support. The purpose of this exploratory, descriptive study was to identify the information and support needs of Israeli women with a family history of breast cancer; discover whether these needs have been met, by whom, and who is the preferred source for them.

Methods: 128 healthy Israeli women, aged 18–65, with a first degree relative with breast cancer completed the adapted Information and Support Needs Questionnaire (ISNQ).

Results: Information needs were ranked above support needs, especially information about disease prevention. The degree to which the needs were met was generally ranked as low, with response to the information needs ranking higher than the response to the support needs. The doctor was the prime source of choice for the information and support needs.

Conclusion: This study contributes to the understanding of the needs of patients' families, provides a framework for the improvement of methods of communication, and a basis for constructing information and support systems. In addition, it highlights the need for a multidisciplinary, proactive approach in health promotion for cancer patients' families. Copyright © 2009 John Wiley & Sons, Ltd.
Simulation of the Substrate Temperature Field for Plasma Assisted Chemical Etching
Authors: Meister Johannes , Böhm Georg , Eichentopf Inga‐Maria , Arnold Thomas
Published: July 2009

Surface figuring using reactive plasma jet machining is a promising technology for the manufacture of optical elements. Due to the pure chemical etching mechanism the material removal rate during plasma jet treatment strongly depends on the workpiece surface temperature, which is influenced by the jet heat flux. This paper presents the basis for an enhanced process simulation by introducing a transient heat transfer model including a moving heat source. A comprehensive method of determination for corresponding model parameters has been developed. It is based on temperature measurements during a well defined etching experiment. The model is able to predict the workpiece surface temperature distribution at any given time.
Electric Characterization and Selective Etching of Aluminum Oxide
Authors: Firek Piotr , Szmidt Jan , Nowakowska‐Langier Katarzyna , Zdunek Krzysztof
Published: July 2009

This work presents results of investigations of Al2O3 thin films, deposited on Si substrates by means of impulse plasma deposition (IPD). Round, aluminum (Al) electrodes were evaporated on the top of deposited layers. Thus, metal‐insulator‐semiconductor (MIS) structures were created with aluminum oxide thin films playing the role of the insulator. It enabled subsequent electrical of studied material. Al2O3 layers were selective etched in a buffer of hydrofluoric acid. The photoresist was used as a masking material. The influence of etching time on the photoresist mask, etching progress, and the state of exposed Si surface was subsequently studied and is discussed. Films' microstructure were additionally studied by scanning electron microscopy (SEM).
Very low prevalence of asthma and allergies in schoolchildren from rural Beijing, China
Authors: Ma Yu , Zhao Jing , Han Z.R. , Chen Yuzhi , Leung Ting F. , Wong Gary W.K.
Published: July 2009

Background

The prevalence of asthma is relatively low in the Chinese population. There is consistent evidence that growing up on a farm is associated with protection against the subsequent development of asthma.

Objective

To compare the prevalence of asthma in schoolchildren from urban and rural China and to assess the possible protection associated with agricultural and livestock farming.

Methods

Random samples of schoolchildren aged 13–14 years from urban Beijing and rural area around Beijing were studied using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase III protocol. Subjects were studied by questionnaires (n = 7,077) and skin‐prick tests (n = 2,126).

Results

The prevalence rates of wheeze in the past year and physicians' diagnosis of asthma were 1.0% and 1.1% in the rural area, and these were significantly lower than 7.2% and 6.3% found in the urban children (P < 0.0001). For the video questionnaire, only 0.3% of rural children reported wheeze in the past year compared with 3.1% in urban children (P < 0.0001). Atopy was 3.22 times higher in urban children compared with rural children (P < 0.0001). For rural schoolchildren, 1,453 (41%) have always been living on agricultural farms since birth and the prevalence rates of their asthma symptoms and atopic sensitization were not significantly different from those who have exposed to livestock farming.

Conclusion

Using the same validated ISAAC questionnaire and objective skin‐prick tests, the prevalence rates of asthma and atopic sensitization in rural Chinese children were significantly lower than urban children. Exposure to agricultural farming conferred the same protection as livestock farming. Pediatr Pulmonol. 2009; 44:793–799. © 2009 Wiley‐Liss, Inc.
Evaluation of CASP8 model quality predictions
Authors: Cozzetto Domenico , Kryshtafovych Andriy , Tramontano Anna
Published: July 2009

The model quality assessment problem consists in the a priori estimation of the overall and per‐residue accuracy of protein structure predictions. Over the past years, a number of methods have been developed to address this issue and CASP established a prediction category to evaluate their performance in 2006. In 2008 the experiment was repeated and its results are reported here. Participants were invited to infer the correctness of the protein models submitted by the registered automatic servers. Estimates could apply to both whole models and individual amino acids. Groups involved in the tertiary structure prediction categories were also asked to assign local error estimates to each predicted residue in their own models and their results are also discussed here. The correlation between the predicted and observed correctness measures was the basis of the assessment of the results. We observe that consensus‐based methods still perform significantly better than those accepting single models, similarly to what was concluded in the previous edition of the experiment. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Effect of astragaloside IV on hepatic glucose‐regulating enzymes in diabetic mice induced by a high‐fat diet and streptozotocin
Authors: Lv Lin , Wu Shao‐Yu , Wang Guang‐Fa , Zhang Jia‐Jie , Pang Jian‐Xin , Liu Zhong‐Qiu , Xu Wei , Wu Shu‐Guang , Rao Jin‐Jun
Published: July 2009

Aim: Hepatic glycogen phosphorylase (GP) and glucose‐6‐phosphatase (G6Pase) are important in control of blood glucose homeostasis, and are considered to be potential targets for antidiabetic drugs. Astragaloside IV has been reported to have a hypoglycemic effect. However, the biochemical mechanisms by which astragaloside IV regulates hepatic glucose‐metabolizing enzymes remain unknown. The present study examines whether GP and G6Pase mediate the hypoglycemic effect of astragaloside IV. Methods: Type 2 diabetic mice were treated with astragaloside IV for 2 weeks. Blood glucose and insulin levels were measured by a glucometer and the ELISA method, respectively. Total cholesterol (TC) and triglyceride (TG) levels were determined using LabassayTM kits. Activities of hepatic GP and G6Pase were measured by the glucose‐6‐phosphate dehydrogenase‐coupled reaction. The mRNA and protein levels of both enzymes were determined by real‐time RT‐PCR and Western blotting. Results: Astragaloside IV at 25 and 50 mg/kg significally decreased the blood glucose, TG and insulin levels, and inhibited the mRNA and protein expression as well as enzyme activity of GP and G6Pase in diabetic mice. Conclusions: Astragaloside IV exhibited a hypoglycemic effect in diabetic mice. The hypoglycemic effect of this compound may be explained, in part, by its inhibition of hepatic GP and G6Pase activities. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of active silicon uptake by rice on 29Si fractionation in various plant parts
Authors: Köster Jan Reent , Bol Roland , Leng Melanie J. , Parker Adrian G. , Sloane Hilary J. , Ma Jian F.
Published: July 2009

Rice (Oryza sativa L.) accumulates large amounts of silicon which improves its growth and health due to enhanced resistance to biotic and abiotic stresses. Silicon uptake and loading to xylem in rice are predominantly active processes performed by transporters encoded by the recently identified genes Lsi1 (Si influx transporter gene) and Lsi2 (Si efflux transporter gene). Silicon deposition in rice during translocation to upper plant tissues is known to discriminate against the heavier isotopes 29Si and 30Si, resulting in isotope fractionation within the plant. We analyzed straw and husk samples of rice mutants defective in Lsi1, Lsi2 or both for silicon content and δ29Si using isotope ratio mass spectrometry (IRMS) and compared these results with those for the corresponding wild‐type varieties (WT). The silicon content was higher in husk than in straw. All the mutant rice lines showed clearly lower silicon content than the WT lines (4–23% Si of WT). The δ29Si was lower in straw and husk for the uptake defective mutant (lsi1) than for WT, albeit δ29Si was 0.3‰ higher in husk than in straw in both lines. The effect of defective efflux (lsi2) differed for straw and husk with higher δ29Si in straw, but lower δ29Si in husk while WT showed similar δ29Si in both fractions. These initial results show the potential of Si isotopes to enlighten the influence of active uptake on translocation and deposition processes in the plant. Copyright © 2009 John Wiley & Sons, Ltd.
Carbon and oxygen isotope microanalysis of carbonate
Authors: Velivetskaya Tatiana A. , Ignatiev Alexander V. , Gorbarenko Sergey A.
Published: July 2009

Technical modification of the conventional method for the δ13C and δ18O analysis of 10–30 µg carbonate samples is described. The CO2 extraction is carried out in vacuum using 105% phosphoric acid at 95°C, and the isotopic composition of CO2 is measured in a helium flow by gas chromatography/isotope ratio mass spectrometry (GC/IRMS). The feed‐motion of samples to the reaction vessel provides sequential dropping of only the samples (without the sample holder) into the acid, preventing the contamination of acid and allowing us to use the same acid to carry out very large numbers of analyses. The high accuracy and high reproducibility of the δ13C and δ18O analyses were demonstrated by measurements of international standards and comparison of results obtained by our method and by the conventional method. Our method allows us to analyze 10 µg of the carbonate with a standard deviation of ±0.05‰ for δ13C and δ18O. The method has been used successfully for the analyses of the oxygen and carbon isotopic composition of the planktonic and benthic foraminifera in detailed palaeotemperature reconstructions of the Okhotsk Sea. Copyright © 2009 John Wiley & Sons, Ltd.
Short‐term dynamics of isotopic composition of leaf‐respired CO2 upon darkening: measurements and implications
Authors: Werner Christiane , Wegener Frederik , Unger Stephan , Nogués Salvador , Priault Pierrick
Published: July 2009

Recent advances in understanding the metabolic origin and the temporal dynamics in δ13C of dark‐respired CO2 (δ13Cres) have led to an increasing awareness of the importance of plant isotopic fractionation in respiratory processes. Pronounced dynamics in δ13Cres have been observed in a number of species and three main hypotheses have been proposed: first, diurnal changes in δ13C of respiratory substrates; second, post‐photosynthetic discrimination in respiratory pathways; and third, dynamic decarboxylation of enriched carbon pools during the post‐illumination respiration period. Since different functional groups exhibit distinct diurnal patterns in δ13Cres (ranging from 0 to 10‰ diurnal increase), we explored these hypotheses for different ecotypes and environmental (i.e. growth light) conditions. Mass balance calculations revealed that the effect of respiratory substrates on diurnal changes in δ13Cres was negligible in all investigated species. Further, rapid post‐illumination changes in δ13Cres (30 min), which increased from 2.6‰ to 5‰ over the course of the day, were examined by positional 13C‐labelling to quantify changes in pyruvate dehydrogenase (PDH) and Krebs cycle (KC) activity. We investigated the origin of these dynamics with Rayleigh mass balance calculations based on theoretical assumptions on fractionation processes. Neither the estimated changes of PDH and KC, nor decarboxylation of a malate pool entirely explained the observed pattern in δ13Cres. However, a Rayleigh fractionation of 12C‐discriminating enzymes and/or a rapid decline in the decarboxylation rate of an enriched substrate pool may explain the post‐illumination peak in δ13Cres. These results are highly relevant since δ13Cres is used in large‐scale carbon cycle studies. Copyright © 2009 John Wiley & Sons, Ltd.
Carbon and hydrogen isotope fractionation of benzene during biodegradation under sulfate‐reducing conditions: a laboratory to field site approach
Authors: Fischer Anko , Gehre Matthias , Breitfeld Jana , Richnow Hans‐Hermann , Vogt Carsten
Published: July 2009

The microbial carbon and hydrogen isotope fractionation of benzene under sulfate‐reducing conditions was investigated within systems of increasing complexity: (i) batch laboratory microcosms, (ii) a groundwater‐percolated column system, and (iii) an aquifer transect. Recent molecular biological studies indicate that, at least in the laboratory microcosms and the column system, benzene is degraded by similar bacterial communities. Carbon and hydrogen enrichment factors (εC, εH) obtained from laboratory microcosms and from the column study varied significantly although experiments were performed under similar redox and temperature conditions. Thus, enrichment factors for only a single element could not be used to distinguish benzene degradation under sulfate‐reducing conditions from other redox conditions. In contrast, using correlation of changes of hydrogen vs. carbon isotope ratios (Λ = Δδ2H/Δδ13C), similar Λ‐values were derived for the benzene biodegradation under sulfate‐reducing conditions in all three experimental systems (Λlaboratory microcosms = 23 ± 5, Λcolumn = 28 ± 3, Λaquifer = 24 ± 2), showing the robustness of the two‐dimensional compound‐specific stable isotope analysis (2D‐CSIA) for elucidating distinct biodegradation pathways. Comparing carbon and hydrogen isotope fractionation data from recent studies, an overlap in Λ‐values was observed for benzene biodegradation under sulfate‐reducing (Λ = 23 ± 5 to Λ = 29 ± 3) and methanogenic (Λ = 28 ± 1 to Λ = 39 ± 5) conditions, indicating a similar initial benzene reaction mechanism for both electron‐acceptor conditions. Copyright © 2009 John Wiley & Sons, Ltd.
Consistent patterns in leaf lamina and leaf vein carbon isotope composition across ten herbs and tree species
Authors: Badeck Franz‐W. , Fontaine Jean‐Louis , Dumas Florian , Ghashghaie Jaleh
Published: July 2009

Wide‐spread post‐photosynthetic fractionation processes deplete metabolites and plant compartments in 13C relative to assimilates to varying degrees. Fragmentation fractionation and exchange of metabolites with distinct isotopic signatures across organ boundaries further modify the patterns of plant isotopic composition. Heterotrophic organs tend to become isotopically heavier than the putative source material as a result of respiratory metabolism. In addition fractionation may occur during metabolite transport across organ and tissue boundaries. Leaf laminae, veins and petioles are leaf compartments that are arranged along a gradient of increasing weight of heterotrophic processes and along a transport chain. Thus, we expect to find consistent patterns of isotopic signatures associated with this gradient. Earlier studies on leaves of Fagus sylvatica, Glycine max, and Saccharum officinarum showed that the organic mass and cellulose of major veins or petioles were consistently more positive than the respective fraction in leaf laminae. The objective of the current study was to assess whether this pattern can be detected in a greater set of plant species. Leaves from ten species were collected in the summer of 2006 outdoors and in glasshouses. Leaf laminae including small veins were separated from the major veins and the isotopic signatures of the organic mass, and the soluble and non‐soluble fractions were measured for laminae and veins separately. The organic mass, and the soluble and non‐soluble fractions of leaf laminae, were depleted in 13C relative to the veins in all cases. A general trend for the signature of organic mass being more depleted in 13C than the soluble fraction is in accordance with well‐known patterns of fractionation between metabolites. Copyright © 2009 John Wiley & Sons, Ltd.
On the application of a ZrO2‐based solid electrolyte in isotope ratio mass spectrometry
Authors: Galimov Eric M. , Sevastyanov Vyacheslav S. , Babulevich Nataliya E. , Tyurina Ekaterina N.
Published: July 2009

The application of a high‐temperature electrochemical reactor based on stabilized zirconium dioxide (0.9 ZrO20.1 Y2O3) for organic gas sampling in continuous‐flow isotope‐ratio mass spectrometry (CF‐IRMS) has been found to be efficient. This solid electrolyte reactor (SER) can also be used as a chromatographic detector for the quantitative measurements of organic gases. A three‐electrode SER system was studied. Complete stoichiometric oxidation of organic gases has been achieved at 900–950°C due to the large catalytic surface area of the porous platinum coating. At this temperature, the oxygen ions formed from the oxygen of ambient air on the outer surface of the reactor migrate through the solid electrolyte under the action of the applied electric field and allow combustion of gases being analyzed to be effected. It should be noted that oxygen gas was not introduced into the gas‐carrier flow. Similar results for the measurements of carbon isotope ratios were obtained at the oxidation of hydrocarbon gases in both the standard and the solid electrolyte reactors. Copyright © 2009 John Wiley & Sons, Ltd.
Contribution of nitrification and denitrification to nitrous oxide emissions from soils after application of biogas waste and other fertilizers
Authors: Senbayram Mehmet , Chen Ruirui , Mühling Karl H. , Dittert Klaus
Published: July 2009

The attribution of nitrous oxide (N2O) emission to organic and inorganic N fertilizers requires understanding of how these inputs affect the two biological processes, i.e. denitrification and nitrification. Contradictory findings have been reported when the effects of organic and inorganic fertilizers on nitrous oxide emission were compared. Here we aimed to contribute to the understanding of such variation using 15N‐labelling techniques. We determined the processes producing N2O, and tested the effects of soil moisture, N rates, and the availability of organic matter. In a pot experiment, we compared soil treated with biogas waste (BGW) and mineral ammonium sulphate (Min‐N) applied at four rates under two soil moisture regimes. We also tested biogas waste, conventional cattle slurry and mineral N fertilizer in a grassland field experiment. During the first 37 days after application we observed N2O emissions of 5.6 kg N2O‐N ha−1 from soils supplied with biogas waste at a rate of 360 kg N ha−1. Fluxes were ca. 5‐fold higher at 85% than at 65% water holding capacity (WHC). The effects of fertilizer types and N rates on N2O emission were significant only when the soil moisture was high. Organic fertilizer treated soils showed much higher N2O emissions than those receiving mineral fertilizer in both, pot and field experiment. Over all the treatments the percentage of the applied N emitted as N2O was 2.56% in BGW but only 0.68% in Min‐N. In the pot experiment isotope labelling indicated that 65–95% of the N2O was derived from denitrification for all fertilizer types. However, the ratio of denitrification/nitrification derived N2O was lower at 65% than at 85% WHC. We speculate that the application of organic matter in conjunction with ammonium nitrogen first leads to a decrease in denitrification‐derived N2O emission compared with soil receiving mineral fertilizer. However, at later stages when denitrification becomes C‐limited, higher N2O emissions are induced when the soil moisture is high. Copyright © 2009 John Wiley & Sons, Ltd.
Kinetic 12C/13C isotope fractionation by invertase: evidence for a small in vitro isotope effect and comparison of two techniques for the isotopic analysis of carbohydrates
Authors: Mauve Caroline , Bleton Jean , Bathellier Camille , Lelarge‐Trouverie Caroline , Guérard Florence , Ghashghaie Jaleh , Tchapla Alain , Tcherkez Guillaume
Published: July 2009

The natural 13C/12C isotope composition (δ13C) of plants and organic compounds within plant organs is a powerful tool to understand carbon allocation patterns and the regulation of photosynthetic or respiratory metabolism. However, many enzymatic fractionations are currently unknown, thus impeding our understanding of carbon trafficking pathways within plant cells. One of them is the 12C/13C isotope effect associated with invertases (EC 3.2.1.26) that are cornerstone enzymes for Suc metabolism and translocation in plants. Another conundrum of isotopic plant biology is the need to measure accurately the specific δ13C of individual carbohydrates. Here, we examined two complementary methods for measuring the δ13C value of sucrose, glucose and fructose, that is, off‐line high‐performance liquid chromatography (HPLC) purification followed by elemental analysis and isotope ratio mass spectrometry (EA‐IRMS) analysis, and gas chromatography‐combustion (GC‐C)‐IRMS. We also used these methods to determine the in vitro 12C/13C isotope effect associated with the yeast invertase. Our results show that, although providing more variable values than HPLC∼EA‐IRMS, and being sensitive to derivatization conditions, the GC‐C‐IRMS method gives reliable results. When applied to the invertase reaction, both methods indicate that the 12C/13C isotope effect is rather small and it is not affected by the use of heavy water (D2O). Copyright © 2009 John Wiley & Sons, Ltd.
The influence of preservation method and time on the δ13C value of dissolved inorganic carbon in water samples
Authors: Taipale Sami J. , Sonninen Eloni
Published: July 2009

The precise δ13C value of dissolved inorganic carbon (DIC) is important for various types of ecological studies. Without a preservation agent, microbial degradation of organic compounds continues in water samples and the δ13C value of DIC will become more depleted with time. HgCl2 or acidification is often used to prevent microbial activity in water samples collected for carbon isotope ratio analyses of DIC. Mercury compounds are toxic and result in waste disposal problems. Other inhibiting agents or preservation methods are therefore needed. Two possible solutions are to use copper sulphate (CuSO4) as a preservative agent or to acidify water samples with phosphoric acid (H3PO4) within 12 mL measurement Exetainers® (septum‐capped vials). We prepared a set of lake water samples in three types of vials: glass vials with silicone/PTFE septa, high‐density polyethylene vials (HD‐PE, scintillation vials) and Exetainers (12 mL) with butyl rubber septa. Samples in glass and PE vials were preserved with and without CuSO4, whereas lake water was injected into the Exetainer and acidified with H3PO4. Isotope ratios were measured in two laboratories over 6 months. The δ13C values of DIC systematically increased with storage time for samples preserved in glass and PE vials with and without CuSO4. A strong correlation between a decrease of CO2 concentration and an increase in DIC δ13C values was found. The δ13C values and DIC concentrations were stable for 6 months in acidified samples stored in Exetainers with butyl rubber septa. Therefore, we conclude that the best method for up to 6 months of storage is to inject samples in the field into butyl rubber septum capped Exetainers® containing H3PO4, thereby avoiding the use of preservatives. Copyright © 2009 John Wiley & Sons, Ltd.
Development and evaluation of a high‐performance liquid chromatography/isotope ratio mass spectrometry methodology for δ13C analyses of amino sugars in soil
Authors: Bodé Samuel , Denef Karolien , Boeckx Pascal
Published: July 2009

Amino sugars have been used as biomarkers to assess the relative contribution of dead microbial biomass of different functional groups of microorganisms to soil carbon pools. However, little is known about the dynamics of these compounds in soil. The isotopic composition of individual amino sugars can be used as a tool to determine the turnover of these compounds. Methods to determine the δ13C of amino sugars using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) have been proposed in literature. However, due to derivatization, the uncertainty on the obtained δ13C is too high to be used for natural abundance studies. Therefore, a new high‐performance liquid chromatography/isotope ratio mass spectrometry (HPLC/IRMS) methodology, with increased accuracy and precision, has been developed. The repeatability on the obtained δ13C values when pure amino sugars were analyzed were not significantly concentration‐dependent as long as the injected amount was higher than 1.5 nmol. The δ13C value of the same amino sugar spiked to a soil deviated by only 0.3‰ from the theoretical value. Copyright © 2009 John Wiley & Sons, Ltd.
Is there any 12C/13C fractionation during starch remobilisation and sucrose export in potato tubers?
Authors: Maunoury‐Danger Florence , Bathellier Camille , Laurette Julien , Fresneau Chantal , Ghashghaie Jaleh , Damesin Claire , Tcherkez Guillaume
Published: July 2009

The δ13C (carbon isotope composition) variations in respired CO2, total organic matter, proteins, sucrose and starch have been measured during tuber sprouting of potato (Solanum tuberosum) in darkness. Measurements were carried out both on tubers and on their growing sprouts for 23 days after the start of sprout development. Sucrose was slightly 13C‐depleted compared with starch in tubers, suggesting that starch breakdown was associated with a small isotope fractionation. In sprouts, all biochemical fractions including sucrose were 13C‐enriched compared with source tuber‐sucrose, suggesting that sucrose translocation from tuber to sprouts fractionated against 12C. However, both apparent fractionations were explained by the consumption of 13C‐depleted carbon for respiration or growth that enriched in the 13C sucrose molecules left behind. In addition, whole tuber sucrose is constantly composed of recent sucrose from starch breakdown and old sucrose associated with an inherited, slightly 13C‐depleted pool. We therefore conclude that any fractionation at either the starch breakdown or the sucrose translocation level is unlikely under our conditions. Copyright © 2009 John Wiley & Sons, Ltd.