bluuebunny/crossref_metadata_2025_split huggingface dataset:
Qualitative and quantitative evaluation of annonaceous acetogenins by high performance liquid chromatography
Authors: Gromek Danuta , Hocquemiller Reynald , Cavé André 
Published: March 2007

AbstractA high performance liquid chromatographic (HPLC) method for the separation, identification and quantification of Annonaceous acetogenins under isocratic or gradient conditions, using ultraviolet, refractometric or evaporative light scattering (ELSD) detection is reported. The system, consisting of a μBondapak C 18 (10 μm) column and a combination of isocratic, step and linear gradient elutions with water and acetonitrile, allowed all six acetogenins of Annona muricata to be well resolved and separated. Well resolved and symetrical peaks were also obtained for other acetogenins with a variety of substitution patterns under isocratic conditions using methanol: water in the ratio of 90:10 to 80:20 or acetonitrile: water in the ratio of 90:10 to 70:30 as mobile phases. The effect of the number, position and type of substituents are discussed. HPLC using μBondapak C 18 (10 μm) column as stationary phase and acetonitrile: water as a mobile phase was successful for the separation of two epimeric acetogenins: rolliniastatin‐1 and rolliniastatin‐2. In order to demonstrate the possibility of quantifying the acetogenins in crude extracts, the quantitative evaluation of annonacin in the seeds of A. muricata was carried out. Semipreparative separations of some acetogenins by HPLC are also reported.
Liquid chromatography coupled with mass spectrometry in the analysis of alkaloids
Authors: Verpoorte R. , Niessen W. M. A. 
Published: March 2007

AbstractGeneral aspects of liquid chromatography‐mass spectrometry (LC‐MS) are discussed such as type of interfaces, ionization modes, solvent compatibility and stationary phases, all with special reference to the analysis of alkaloids. The literature on LC‐MS of various classes of alkaloids is reviewed.
A general method for high performance liquid chromatography of pyrrolizidine alkaloid free bases andN‐oxides
Authors: Brown Milford S. , Molyneux Russell J. , Roitman James N. 
Published: March 2007

AbstractA reverse phase, ion‐pair high performance liquid chromatographic method for the separation of five distinct structural subclasses of pyrrolizidine alkaloids has been developed. The system consists of a μBondapak CN or Nova‐Pak Phenyl column in a radial compression apparatus, eluted isocratically with methanol: water (27:73) containing 0.01 M dibutylammonium phosphate. Symmetrical, well‐resolved peaks were obtained for 30 pyrrolizidine alkaloids within a 15 min elution time. Both the free base and theN‐oxide forms of the alkaloids can be analysed under the same conditions. The elution times are indicative of the relative polarities of the alkaloids being separated.
Determination of cyanogenic glucosides in white clover (Trifolium repens L.) by high performance liquid chromatography
Authors: Stochmal A. , Oleszek W. 
Published: March 2007

AbstractA high performance liquid chromatographic method used for the determination of cyanogenic glucosides in flax seed has been modified to make it suitable for the analysis of these compounds in dried white clover (Trifolium repens L.) samples. Moreover, the extraction of glycosides from clover samples and purification of exracts on the C18 support prior to analysis has been developed. Linamarin and lotaustralin were identified in T. repens cv. Armena in concentrations of 1.29 and 3.13 mg/g of dry matter, respectively.
Accurate molecular mass determination by mass spectrometrical techniques: Differentiation of soybean lipoxygenase isoenzymes
Authors: Scheller G. , Stahl B. , Weyd S. , Karas M. , Hillenkamp F. , Schreier P. 
Published: March 2007

AbstractMolecular mass determinations for the four lipoxygenase isoenzymes from soybean seeds were compared using two mass spectrometrical (MS) techniques as well as gel permeation chromatography and sodium dodecylsulphate‐polyacrylamide gel electrophoresis. The data obtained by MS techniques were in good agreement with the molecular masses evaluated from the corresponding cDNA. The MS techniques allowed to distinguish between the lipoxygenase isoenzymes and to check the purity of enzyme preparations.
Rapid high performance liquid chromatographic quantification of valepotriates in hairy root cultures of Valeriana officinalis L. var. sambucifolia Mikan
Authors: Gränicher F. , Christen P. , Vuagnat P. 
Published: March 2007

AbstractThe quantitative determination of valepotriates in Valeriana officinalis L. var. sambucifolia Mikan hairy roots by a new high performance liquid chromatographic (HPLC) method is reported. The quantification is based on the simultaneous isocratic determination of the monoene and diene derivatives at one wavelength (208 nm). The analysis is rapid and highly reproducible, giving results similar to those obtained with a currently used HPLC method in which valepotriate quantification is undertaken using two separate runs.
Structural elucidation of infuscatin, a diterpenoid from Salvia infuscata
Authors: Ortega Alfredo , Maldonado Emma , Jankowski Christopher K. , Van Calsteren Marie Rose , Díz† Eduardo 
Published: March 2007

AbstractA new trihydroxy neoö‐clerodane diterpene, infuscatin, has been isolated from Salvia infuscata. Its structure was established as 15,16‐epoxy‐4β, 8α, 10β‐trihydroxy neo‐cleroda‐1,13(16),14‐trien‐17,12R,18,19‐diolide by spectroscopic means, including 1H1H COSY, 13C NMR, DEPT 135, DEPT 90, COLOC and NOE differential experiments.
Determination ofS‐adenosyl‐L‐methionine andS‐adenosyl‐L‐homocysteine in plants
Authors: Edwards Robert 
Published: March 2007

AbstractA sensitive method has been developed for the simultaneous determination of S‐adenosyl‐L‐homocysteine (SAH) and S‐adenosyl‐L‐methionine (SAM) in a variety of plant tissues. Samples were extracted in acid and the extracts cleaned up and concentrated by a combination of partitioning with diethyl ether and cation exchange chromatography using phosphocellulose paper. After elution from the phosphocellulose paper with a minimal volume of 6M HCI, SAM and SAH were quantified by ion‐pair reversed phase high performance liquid chromatography with UV detection at 257 nm. Recoveries were monitored using a spike of [14C]‐SAM and were typically between 30 and 40%. In alfalfa, peas and maize the levels of SAM exceeded those of SAH, and in peas levels of SAM were higher in young roots and shoots than in older tissues. When alfalfa cell cultures were treated with a fungal elicitor preparation, the levels of SAM and SAH increased approximately two‐fold over a 12 h period and then declined.
Health literacy and patient understanding of screening tests for aneuploidy and neural tube defects
Authors: Cho Regina N. , Plunkett Beth A. , Wolf Michael S. , Simon Charla E. , Grobman William A. 
Published: March 2007

AbstractObjectiveTo determine if health literacy is associated with patient understanding of prenatal screening tests for fetal aneuploidy and neural tube defects.MethodsWe performed a prospective observational study on a cohort of English‐speaking patients receiving prenatal care in two resident‐staffed ambulatory clinics. Health literacy was measured using the Rapid Estimate of Adult Literacy in Medicine‐7. Understanding of the prenatal screening tests was assessed using a modified Maternal Serum Screening Knowledge Questionnaire.ResultsOver an 8‐month period, 125 patients were approached, and 101 (81%) consented to the study. Thirty‐eight (38%) women demonstrated low health literacy. Patients with low health literacy were more likely to demonstrate inadequate understanding when compared to those with adequate health literacy (97% versus 11%, respectively; P < 0.01). Similarly, patients with < 12th grade education were more likely to have inadequate understanding when compared to patients with > 12th grade education (53% versus 30%, respectively; P = 0.02). Health literacy is a more sensitive and specific predictor of inadequate understanding than education (sensitivity 84% versus 70%, respectively, P < 0.05; specificity 98% versus 47%, respectively, P < 0.05).ConclusionPatients with low health literacy are more likely to demonstrate inadequate understanding of these prenatal screening tests than women with adequate health literacy. Copyright © 2007 John Wiley & Sons, Ltd.
The correlation between coping strategies, doctor–patient/spouse relationships and psychological distress among women cancer patients and their spouses
Authors: Gilbar Ora , Zusman Alla 
Published: March 2007

AbstractObjectives: The objectives of the study were (1) to assess similarities and differences between women cancer patients and their spouses in terms of coping strategies, psychological distress and doctor–patient/spouse relationships; and (2) to investigate the impact of formal social support, namely the doctor–patient relationship and coping strategies, on patients' and spouses' psychological distress.Method: Fifty‐seven women with cancer, and their spouses, completed questionnaires that measured distress (BSI), coping strategies (PF, EF) and doctor–patient relationships (Pat, Md).Results: Patient distress was greater than that of spouses. Patients used more strategies involving problem‐focused coping than spouses. A positive relationship was found between patients and spouses in terms of psychological distress, paternalism and emotion‐focused strategies. Emotion‐focused strategies were found to impact patient psychological distress, as indicated in a hierarchical regression model.Conclusion: The paternalism relationship model is an important factor in patient psychological distress but not in spousal psychological distress. Copyright © 2007 John Wiley & Sons, Ltd.
Exploring the economic impact of breast cancers during the 18 months following diagnosis
Authors: Gordon Louisa , Scuffham Paul , Hayes Sandi , Newman Beth 
Published: March 2007

AbstractThe economic impact on individuals with breast cancer is not well understood. We sought to identify and describe the direct and indirect economic losses to breast cancer survivors in Australia. A longitudinal, population‐based study of 287 women was used to explore economic outcomes (costs and lost income) for women with breast cancer 0–18 months post‐diagnosis. Survey methods collected data on out‐of‐pocket costs, care‐giving support, paid and unpaid work reductions, and perceptions from participants on these financial impacts. Bootstrapping was used to estimate 95% confidence intervals around means. Data were sub‐grouped by cost type, age category and disease severity. Lost income, health service expenditures and lost unpaid work were the greatest sources of economic burden. Women with positive lymph nodes reported significantly higher costs than those with negative lymph nodes (US$6674 versus US$3533, p<0.001), and younger women (⩽50 years) with positive lymph nodes experienced costs 80% greater than older women (US$8880 versus US$4937, p<0.001). Economic costs related to breast cancer may continue to affect women 18 months post‐diagnosis. Economic research adds an important dimension for understanding the impact of breast cancer, and findings may be used to help improve supportive care services for women and families confronted by this disease. Copyright © 2007 John Wiley & Sons, Ltd.
Assessment is not enough: a randomized controlled trial of the effects of HRQL assessment on quality of life and satisfaction in oncology clinical practice
Authors: Rosenbloom Sarah K. , Victorson David E. , Hahn Elizabeth A. , Peterman Amy H. , Cella David 
Published: March 2007

AbstractThe potential benefits of health‐related quality of life (HRQL) assessment in oncology clinical practice include better detection of problems, enhanced disease and treatment monitoring and improved care. However, few empirical studies have investigated the effects of incorporating such assessments into routine clinical care. Recent randomized studies have reported improved detection of and communication about patients' concerns, but few have found effects on patient HRQL or satisfaction. This study examined whether offering interpretive assistance of HRQL results would improve these patient outcomes. Two hundred and thirteen participants with metastatic breast, lung or colorectal cancer were randomly assigned to one of three conditions: usual care; HRQL assessment or HRQL assessment followed by a structured interview and discussion. Interviews about patients' assessment responses were conducted by a research nurse, who then presented HRQL information to the treating nurse. HRQL and treatment satisfaction outcomes were assessed at 3 and 6 months. No significant differences were found between study conditions in HRQL or satisfaction. Results suggest that routine HRQL assessment, even with description of results, is insufficient to improve patient HRQL and satisfaction. It is suggested that positive effects may require supplementing assessment results with specific suggestions for clinical management changes. Copyright © 2007 John Wiley & Sons, Ltd.
The lower limit of mountain permafrost in the Russian Altai Mountains
Authors: Fukui Kotaro , Fujii Yoshiyuki , Mikhailov Nikolai , Ostanin Oleg , Iwahana Go 
Published: March 2007

AbstractPermafrost‐indicator features, such as rock glaciers, pingos and ice‐wedge polygons, exist at many locations in and around the South Chuyskiy Range of the Russian Altai Mountains (∼50°N). The distribution of these features suggests that the altitudinal range of the sporadic/patchy permafrost zones and the widespread discontinuous/continuous permafrost zones are 1800–2000 m ASL and above 2000 m ASL, respectively. The lower limit of discontinuous permafrost is approximately 200 m lower than in the Mongolian Altai, which are at a similar latitude. Cold air drainage and/or temperature inversions during winter within U‐shaped valleys together with a thin snow cover because of low precipitation during the same season likely cause the lower permafrost limit in the study area. The calibrated 14C ages of tree remnants found in a rock glacier front in the lower Akkol valley were 293 ± 21 years BP and 548 ± 21 years BP. Given the time of emergence from beneath the Sofiyskiy glacier, this rock glacier developed between 3800–2600 and 550 years BP. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of the HLA class I associated peptide repertoire in a hepatocellular carcinoma cell line reveals tumor‐specific peptides as putative targets for immunotherapy
Authors: Alvarez Iñaki , Carrascal Montserrat , Canals Francesc , Muixí Laia , Abián Joaquín , Jaraquemada Dolores 
Published: March 2007

AbstractHLA class I molecules present peptides on the cell surface to CD8+ T cells. The repertoire of peptides that associate to class I molecules represents the cellular proteome. Therefore, cells expressing different proteomes could generate different class I‐associated peptide repertoires. A large number of peptides have been sequenced from HLA class I alleles, mostly from lymphoid cells. On the other hand, T cell immunotherapy is a goal in the fight against cancer, but the identification of T cell epitopes is a laborious task. Proteomic techniques allow the definition of putative T cell epitopes by the identification of HLA natural ligands in tumor cells. In this study, we have compared the HLA class I‐associated peptide repertoire from the hepatocellular carcinoma (HCC) cell line SK‐Hep‐1 with that previously described from lymphoid cells. The analysis of the peptide pool confirmed that, as expected, the peptides from SK‐Hep‐1 derive from proteins localized in the same compartments as in lymphoid cells. Within this pool, we have identified 12 HLA class I peptides derived from HCC‐related proteins. This confirms that tumor cell lines could be a good source of tumor associated antigens to be used, together with MS, to define putative epitopes for cytotoxic T cells from cancer patients.
Proteomic and transcriptomic analysis of human CD8+ T lymphocytes over‐expressing telomerase
Authors: Thadikkaran Lynne , Menzel Olivier , Tissot Jean‐Daniel , Rufer Nathalie 
Published: March 2007

AbstractHuman T lymphocytes have a finite life span resulting from progressive telomere shortening that occurs at each cell division, eventually leading to chromosomal instability. It has been shown that ectopic expression of the human telomerase reverse transcriptase (hTERT) gene into various human cells results in the extension of their replicative life span, without inducing changes associated with transformation. However, it is still unclear whether cells that over‐express telomerase are physiologically and biochemically indistinguishable from normal cells. To address this question, we compared the proteome of young and aged human CD8+ T lymphocytes with that of T cells transduced with hTERT. Interestingly, we found no global changes in the protein pattern in young T cells, irrespective of telomerase expression. In contrast, several relevant proteins with differential expression patterns were observed in hTERT‐transduced T cells with extended life span upon long‐term culture. Altogether, our data revealed that T lymphocytes over‐expressing telomerase displayed an intermediate protein pattern, sharing a similar protein expression not only with young T cells, but also with aged T cells. Finally, the results obtained from this global proteomic approach are in agreement with the overall gene transcription profiling performed on the same T‐cell derived clones.
Non‐radiative relaxation of excited states of non‐bridging oxygen hole centers in silica
Authors: Zatsepin A. F. , Kortov V. S. , Biryukov D. Yu. 
Published: March 2007

AbstractProcesses involved in the excited‐state relaxation of non‐bridging oxygen hole centers (NBOHCs) were studied in glassy SiO2 using luminescence, optical absorption and photoelectron emission spectroscopy. It was shown that photoexcited NBOHCs generally have three channels of relaxation. Along with radiative transitions responsible for the luminescence band at 1.9 eV, two non‐radiative channels caused by transitions between levels of photoexcited state were observed. The first non‐radiative channel was connected with transformation of the electron excitation energy to thermal lattice vibrations and represented an intracenter process of NBOHC luminescence quenching (the activation barrier was 0.05 eV). The second non‐radiative relaxation channel for excited NBOHCs was identified as thermally activated external luminescence quenching with the energy barrier of 0.46 eV. As a result of realization of the specified process, the transfer of the excitation energy from NBOHCs to oxygen‐deficient centers (ODCs) acting as electron emitters took place. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
EXAFS and XRD studies of nanocrystalline cerium oxide: the effect of preparation method on the microstructure
Authors: Savin S. L. P. , Chadwick A. V. , Smith M. E. , O'Dell L. A. 
Published: March 2007

AbstractThere is considerable interest in nanocrystalline materials due to their unusual properties, such as enhanced ionic conductivity in the case of nanocrystalline ionic solids. This has potential commercial applications, particularly for oxide ion conductors. However, a detailed knowledge of the microstructure is important in fully understanding the novel properties exhibited by nanocrystalline materials. The final microstructure of a material is dependent on the preparation method used, for example, sol‐gel and ball‐milling methods are commonly used in the preparation of nanocrystalline oxides. Additionally, there is a problem in maintaining the materials in nanocrystalline form when they are subjected to elevated temperatures. We have been exploring strategies to restrict the growth of nanocrystalline oxides and have found that adding a small amount of an inert material, e.g. SiO2 or Al2O3, is particularly effective. We will report XRD and EXAFS studies of nanocrystalline ceria prepared by sol‐gel, sol‐gel pinned and ball‐milling methods and the effect of preparation method on the final microstructure. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation into thallium sites and defects in doped scintillation crystals
Authors: Blacklocks A. N. , Chadwick A. V. , Jackson R. A. , Hutton K. B. 
Published: March 2007

AbstractThallium doped caesium iodide, CsI(Tl), and sodium iodide, NaI(Tl) are two of the most efficient scintillators developed and are already widely used for radiation detection and imaging applications. Their use in fast imaging applications however has been hindered by a long lasting high level of afterglow – the percentage of the luminescence pulse remaining a short time after excitation. Very little is known about the point defects in these crystals, such as structure and concentrations, and the first step to understanding the causes of the afterglow is to understand the nature of the defects responsible for the scintillation. In this paper the local structure of the thallium activator ion has been investigated via EXAFS spectroscopy and some basic intrinsic defects calculated using the General Utility Lattice Program (GULP). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Origin of 1/f noise as a runaway phenomenon due to the zeropoint field (ZPF) of quantum electrodynamics (QED)
Authors: Cavalleri Giancarlo , Bosi Leonardo 
Published: March 2007

AbstractThe origin of electron transport noise whose power spectral density is inversely proportional to the frequency f has been realized after 80 years of attempts. Here we give its conceptual explanation that has required a sequence of five ideas and corresponding results: 1) The reduction of the nonlinear Boltzmann equation with electron‐electron (e –e) interaction to a Fokker‐Planck (denoted as e –e FP) equation containing two electron collision frequencies ν1 and ν2; 2) the application of the e –e FP to materials and its‐steady state solution that depends on ν1(υ), ν2(υ), and the square a2 of the acceleration a = e E/m; 3) the steadystate solution of the e –e FP equation becomes similar to the Fermi‐Dirac distribution function if a2 is considered as mainly due to the zero‐point field (ZPF) of quantum electrodynamics (QED) or, realistically, of stochastic electrodynamics (SED); 4) in this δυ range the e –e FP is similar to the usual FP solved by Stenflo when ν (υ) ∝ 1/υ. It is just because of aZPF that for any conduction current there is always a small interval δυ for the electron speed υ where ν1 ∝ ν2 ∝ 1/υ, condition that is at the threshold of runaways. The relevant time‐dependent Green solution of the e –e FP equation decreases as τ–ε with ε < 0.006. The consequent power spectral density S (f) turns out to be ∝ 1/f1–ε in an indefinite medium. Our S (f) also depends on the electrons concentration N and excellently fits the experimental data; 5) In a finite sample the memory or a fluctuation is preserved beyond the electron transit time because the transmission of information is mainly due to e –e interactions and to the diffusion coefficient that diverges at the threshold of runaways. A pimple (due to fluctuation) in the distribution function on the electron speeds is almost crystallized, decaying as τ–0.005 without any cut‐off at the transit time. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computer modelling of the optical properties of rare‐earth doped metal fluorides
Authors: Jackson R. A. , Valerio M. E. G. , Amaral J. B. , Couto dos Santos M. A. , Maddock E. M. 
Published: March 2007

AbstractA computational approach to calculating the optical properties of doped metal fluoride materials is presented, and applied to rare earth doping in the BaY2F8 and LaF3 systems. Optimal locations for dopant ions are predicted, along with solution energies and charge compensation mechanisms. Energy levels for dopant ions are predicted using adapted crystal field calculations. The results of the predictions are compared with experimental data. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)