bluuebunny/crossref_metadata_2025_split huggingface dataset:
Essential oil constituents of three varieties of Kenyan sweet oranges (Citrus sinensis)
Authors: Njoroge Simon Muhoho , Koaze Hiroshi , Karanja Paul Nyota , Sawamura Masayoshi 
Published: May 2004

AbstractThe volatile components of peel essential oils of Salustiana (Citrus sinensis Osbeck forma Salustiana), Valencia (C. sinensis Osbeck forma Valencia) and Washington navel (C. sinensis Osbeck forma Washington navel) sweet oranges grown in Kenya were isolated by cold‐pressing and determined by GC and GC‐MS. A total of 56 components were identiﬁed in Salustiana, 73 in Valencia and 72 in Washington navel peel oils. The identiﬁed components amounted to 98.7, 97.8 and 97.4% of the total volatiles of each oil, respectively. Monoterpene hydrocarbons largely dominated in the volatile fraction of the Salustiana (96.9%), Valencia (94.5%) and Washington navel (92.7%) oils. In each oil, limonene, α‐pinene, sabinene and α‐terpinene were the major compounds. Sesquiterpene hydrocarbons amounted to 0.1% of the total volatiles of Valencia and Washington navel oils, where (E,E)‐α‐farnesene was the main compound. The total oxygenated compounds amounted to 1.7, 3.4 and 4.5% of the Salustiana, Valencia and Washington navel volatiles. Linalool, decanal, (Z)‐carvone, (Z)‐carveol, (E)‐carveol, nootkatone and sabina ketone were the main components. The three sweet orange varieties could be differentiated by the unique presence of α‐phellandrene and γ‐terpinene in Salustiana, β‐phellandrene, (Z)‐nerolidol, aromadendrene in Valencia and p‐cymene, β‐sinensal and dodecanoic acid in Washington navel oils. Copyright © 2004 John Wiley & Sons, Ltd.
Annexin 2 expression is reduced in human osteosarcoma metastases
Authors: Gillette Jennifer M. , Chan Daniel C. , Nielsen‐Preiss Sheila M. 
Published: May 2004

AbstractOsteosarcoma is an aggressive primary bone cancer affecting primarily children and young adults. The development of valuable diagnostic indicators and therapeutic agents will be enhanced by the identification and characterization of genes that contribute to its aggressive behavior. We used representational difference analysis to isolate genes differentially expressed between primary human osteosarcoma tumors and subsequent metastatic lung lesions to identify genes potentially involved in metastatic potential. Several genes were differentially expressed between the two tumor populations, including annexin2. The levels of annexin2 mRNA and protein inversely correlated with metastatic potential in a subset of human osteosarcoma tumor specimens, as well as in a human osteosarcoma cell line selected for increased metastatic potential. Annexin2 has been described in several cellular localizations with various functional implications, many of which may be relevant to metastatic potential. Therefore, the subcellular localization of endogenous annexin2 protein was evaluated biochemically by subcellular fractionation and immunologically by flow cytometry and immunofluorescence in osteoblastic cells. Annexin2 was localized to the cytoplasm and intracellular aspect of the plasma membrane, excluded from the nucleus and undetectable on the cell surface or in the conditioned medium. Overexpression of annexin2 in osteosarcoma cells did not alter several in vitro phenotypes often used to assess metastatic potential including motility, adhesion, and proliferation. However, our previous data have implicated annexin2 in the mineralization process of osteoblastic cells in vitro. Consistent with an increase in differentiation‐induced mineralization, there was diminished tumorigenicity and experimental metastatic potential of osteosarcoma cells overexpressing annexin2. These data suggest that annexin2 may downregulate osteosarcoma aggressiveness by inducing a more differentiated state in osteoblastic cells. © 2004 Wiley‐Liss, Inc.
Mechanisms of cardioprotection by lysophospholipids
Authors: Karliner Joel S. 
Published: May 2004

AbstractThe lysophospholipids sphingosine 1‐phosphate (S1P) and lysophosphosphatidic acid (LPA) reduce mortality in hypoxic cardiac myocytes. S1P is also cardioprotective in both mouse and rat models of cardiac ischemia/reperfusion (I/R) injury. Although these results are consistent with prior work in other cell types, it is not known what signaling events are critical to cardioprotection, particularly with respect to ceramide and the preservation of mitochondrial function, which is essential for cardiac cell survival. Neither receptor regulation nor signaling has been studied during I/R in the heart with or without the application of S1P or LPA. The role of sphingosine kinase in I/R and in ischemic preconditioning (IPC) has not been defined, nor has the fate or function of S1P generated by this enzyme, particularly during preconditioning or I/R, been elucidated. Whether S1P infused systemically in animal models of myocardial infarction in which survival is an end‐point will be hemodynamically tolerated has not been determined. If not, the substitution of agents such as the monosialoganglioside GM‐1, which activates sphingosine kinase, or the development of alternative ligands for S1P receptors will be necessary. © 2004 Wiley‐Liss, Inc.
Comparison of the expression of β‐catenin in hepatocellular carcinoma in areas with high and low levels of exposure to aflatoxin B1
Authors: Chen Ban Ke , Singh Harjit , Krishnan R. , Fong Seow Heng 
Published: May 2004

AbstractBackground and ObjectivesPrevious studies showed that the frequency of β‐catenin mutation was different in mice when induced by different chemicals. The aim of this study is to compare the expression of β‐catenin and p53 in hepatocellular carcinoma (HCC) from areas with exposure to high and low levels of aflatoxin B1 (AFB1).MethodsThirty‐five and twenty HCC samples from Guangxi and Malaysia, respectively, were studied. The expression of β‐catenin and p53 was determined by immunohistochemistry.ResultsThe overexpression of β‐catenin was detected in 65.7% of HCC tissues and 37.1% in adjacent liver tissues samples from Guangxi, China. Similarly, overexpression of β‐catenin was also detected in 60.0% of HCC tissues and in 35.0% of adjacent liver tissues samples from Malaysia. The overexpression of p53 was detected in 42.9% of HCC specimens from Guangxi and in 25.0% of HCC specimens from Malaysia. There was a relationship between the expression of β‐catenin and hepatitis B virus (HBV) infection in the adjacent liver tissues in Guangxi, and between the expression of β‐catenin and p53 in HCC tissues in Malaysia.ConclusionsThe differences in the exposure to AFB1 did not affect the overexpression of β‐catenin in the development of HBV‐associated HCC. J. Surg. Oncol. 2004;86:157–163. © 2004 Wiley‐Liss, Inc.
On the use of “fast kinetics” to determine the mechanism of ligand substitution at a solvated transition‐metal intermediate
Authors: Schultz Richard H. 
Published: May 2004

AbstractSubstitution of the weakly‐coordinated solvent molecule at a solvated transition‐metal intermediate is frequently investigated by “fast kinetic” methods. In typical experiments, the kinetics of the reaction are determined by following the time dependence of the changes in the reaction mixture's UV‐visible or infrared spectrum following photolytic creation of the intermediate. We consider the two limiting mechanisms (associative and dissociative), as well as the case of competition between them, and show that under typical “fast kinetics” experimental conditions, the different mechanisms are kinetically indistinguishable. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 427–433, 2004
On the Beckmann rearrangement of ketoximes: A kinetic study in trifluoromethanesulfonic acid
Authors: Marziano N. C. , Ronchin L. , Tortato C. , Tonon O. , Bertani R. 
Published: May 2004

AbstractThe formation and the destruction of an intermediate involved in the Beckmann rearrangement of 2,4,6‐trimethylacetophenone oxime have been studied in concentrated trifluoromethanesulfonic acid by kinetic and spectroscopic measurements. Observed (kobs) and thermodynamic rate constants (ko) have been estimated and the values compared with the ones obtained in perchloric, sulfuric, and methanesulfonic acids. In the range 80–100 wt% of sulfuric acid, combined analysis of kobs and ko rates shows a specific catalysis due to [H2SO4] species. In trifluoromethanesulfonic acid, lower rate constants, compared to the values in sulfuric acid, have been observed which differ at 99 wt% by a factor of 103 ca. The catalytic effect of different strong acids, the structure of the intermediate inferred from Raman and NMR spectra, and the role of the ion‐pairs involved in the reaction are discussed. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 417–426, 2004
Commercial agriculture as creative destruction or destructive creation: a case study of chili cultivation and plant‐pest disease in the southern Yucatán region
Authors: Keys E. 
Published: May 2004

AbstractAgricultural change encompasses both social and ecological alterations, some negative, some positive. Studies of land change and land degradation treat plant pest and diseases triggered by agricultural change in an inconsistent fashion. A study of the southern Yucatán region of Mexico reveals that the shift to commercial chili cultivation yields both positive and negative consequences, akin to the concepts of creative destruction and destructive creation. The negative consequences are dramatically amplified by persistent plant pest and diseases apparently triggered by the means of cultivation and by the inclusion of the region into a national marketing structure. Thus, while providing economic benefits to some of the farmers of the region the short‐ and long‐term impacts of chili cultivation on farmer households is mixed. Studies of agricultural land‐use change and household economics will benefit by incorporating plant pests and diseases as one of the suite of factors involved in land degradation. Copyright © 2004 John Wiley & Sons, Ltd.
Comparison of continuous and discontinuous FK506 administration on autograft or allograft repair of sciatic nerve resection
Authors: Udina Esther , Gold Bruce G. , Navarro Xavier 
Published: May 2004

AbstractAn immunosuppressant drug that also possesses neuroregenerative properties, FK506 enhances the rate of axonal regeneration and improves recovery after nerve lesions. Nevertheless, prolonged immunosuppression may not be justified to assure the success of nerve regeneration. In this study, we compare the effects of continuous and discontinuous FK506 treatment on regeneration and reinnervation after sciatic nerve resection repaired with autologous or allogenic grafts in the mouse. For each type of repair, one group received FK506 (5 mg/kg) for 4 months, whereas a second group was treated with FK506 at 5 mg/kg for 5 weeks followed by 3 mg/kg for 4 weeks; a control group received saline only. Functional reinnervation was assessed by noninvasive methods to determine recovery of motor, sensory, and autonomic functions in the hind paw over 4 months after operation. Morphological analysis of the regenerated nerves was performed at the termination of the study. Autografts and allografts treated with sustained FK506 (5 mg/kg) reached high levels of reinnervation and followed a course of recovery faster than controls. The numbers of myelinated fibers also were similar. Allografts without immunosuppression demonstrated a slower rate of regeneration, exhibiting lower final levels of recovery compared with other groups and containing fewer numbers of regenerating myelinated fibers. Withdrawal of immunosuppressant therapy resulted in a decline in the degree of reinnervation in all functions tested during the third month, with stabilization between the third and fourth months. The number of regenerated myelinated fibers in the group was significantly lower than in autografts. Thus, continuous or discontinuous FK506 administration slightly accelerated the rate of reinnervation in autografts. In allograft repair, FK506 significantly enhanced both the rate and degree of regeneration and recovery, but its withdrawal resulted in graft rejection, a marked deterioration in function, and loss of regenerating fibers. Muscle Nerve 29: 812–822, 2004
An improved algorithm for the distance constrained p‐center location problem with mutual communication on tree networks
Authors: Tamir Arie 
Published: May 2004

AbstractIn a recent article Averbakh and Berman present an O(p3 + n2) serial algorithm to solve the distance constrained p‐center location problem with mutual communication on a tree network with n nodes. In this note we suggest two simple modifications leading to the improved (subquadratic in n), O(p3 + p(n + p)log2(n + p)) complexity bound. We also present a new O(p2n log n log(n + p)) algorithm for the discrete version of this problem. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(1), 38–40 2004
Sinorhizobium meliloti metabolism in the root nodule: A proteomic perspective
Authors: Djordjevic Michael A. 
Published: May 2004

AbstractThe proteome of the model symbiotic bacterium, Sinorhizobium meliloti was examined to determine the enzymatic reactions and cell processes that occur when S. meliloti occupies the root nodules of Medicago truncatula and Melilotus alba. The proteomes of the nodule bacteria were compared to that of S. meliloti grown under laboratory cultured conditions as an additional control. All the detectable protein spots on the two‐dimensional (2‐D) gels between pH 4–7 were analyzed. In total, the identity of proteins in 1545 spots from 2‐D gels was determined using peptide mass fingerprinting. There were clear differences in the proteome of nodule bacteria and cultured bacteria and putative nodule‐specific and nodule suppressed proteins were identified. The data were analyzed using metabolic pathway prediction programs and used to review the biochemical and genetic studies that had been done previously on S. meliloti over several decades. There was a broad congruency between the proteomic and biochemical data when the overall pathways of central carbon and nitrogen metabolism were considered. A selective suite of ABC‐type transporters was present in nodule bacteria that were biased towards the transport of amino acids and inorganic ions (P and Fe) suggesting that a highly specialized nutrient exchange was occurring between the nodule bacteria and the host. Proteins prominent in nodule bacteria were those involved in the pathways for vitamin synthesis and stress‐related processes (chaperoning, heat shock, detoxification of reactive oxygen species, regulation of stress and osmo‐regulation). Some of these proteins were found only in nodule bacteria. These results show the extent of the shift in metabolism that occurs when S. meliloti invades legume plants and establishes a nitrogen fixing symbiosis.
Proteome reference maps of Medicago truncatula embryogenic cell cultures generated from single protoplasts
Authors: Imin Nijat , De Jong Femke , Mathesius Ulrike , van Noorden Giel , Saeed Nasir A. , Wang Xin‐Ding , Rose Ray J. , Rolfe Barry G. 
Published: May 2004

AbstractUsing a combination of two‐dimensional gel electrophoresis (2‐DE) protein mapping and mass spectrometry (MS) analysis, we have established proteome reference maps of Medicago truncatula embryogenic tissue culture cells. The cultures were generated from single protoplasts, which provided a relatively homogenous cell population. We used these to analyze protein expression at the globular stages of somatic embryogenesis, which is the earliest morphogenetic embryonic stage. Over 3000 proteins could reproducibly be resolved over a pI range of 4–11. Three hundred and twelve protein spots were extracted from colloidal Coomassie Blue‐stained 2‐DE gels and analyzed by matrix‐assisted laser desorption/ionization‐time of flight MS analysis and tandem MS sequencing. This enabled the identification of 169 protein spots representing 128 unique gene products using a publicly available expressed sequence tag database and the MASCOT search engine. These reference maps will be valuable for the investigation of the molecular events which occur during somatic embryogenesis in M. truncatula. The proteome reference maps and supplementary materials will be available and updated for public access at http://semele.anu.edu.au/.
Polyquinolines containing both spirobifluorene and cardofluorene units: Synthesis and characterization
Authors: Chen Ching‐Hsin , Shu Ching‐Fong 
Published: May 2004

AbstractWe have synthesized aromatic polyquinolines containing both spirobifluorene and cardofluorene moieties in the main chain by applying acid‐catalyzed Friedländer quinoline synthesis. The incorporation of these rigid nonplanar structures into the polymer backbone, which restricts segmental mobility, significantly increases both the glass‐transition temperature and thermal stability, while providing enhanced solubility as a result of a decrease in the degree of molecular packing and crystallinity. We have also examined the optical and electrochemical properties of these polyquinolines. The low‐lying lowest unoccupied molecular orbital energy level and quasireversible electrochemical reduction of these polyquinolines suggest their potential for use as electron‐injecting/transporting materials in polymer light‐emitting diodes. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3314–3322, 2004
Local segmental relaxation in bidisperse polystyrenes
Authors: Robertson C. G. , Roland C. M. 
Published: May 2004

AbstractDynamic mechanical results are reported for segmental relaxation of monodisperse polystyrenes (PSs) with molecular weights of 0.7, 3, 18, and 104 kg/mol and bidisperse PSs created from blending pairs of these materials. The data for the monodisperse polymers confirm previous findings; namely, there is an increase in the glass‐transition temperature normalized temperature dependence of the segmental relaxation times (fragility) with increasing molecular weight, along with a breakdown of the correlation between the fragility and the breadth of the relaxation function. For both the monodisperse and bidisperse PSs, the glass‐transition temperature is a single function of the average number of chain ends, independent of the nature of the molecular weight distribution. It is also found that these materials exhibit fragilities that uniquely depend on the number‐average molecular weight, that is, on the concentration of chain ends. In blends with linear PS, cyclic PS with a low molecular weight behaves as a high polymer, similar to its neat behavior, reflecting the overriding importance of chain ends. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2604–2611, 2004
Network structure and swelling–shrinking behaviors of pH‐sensitive poly(acrylamide‐co‐itaconic acid) hydrogels
Authors: Çaykara Tuncer , Doǧmuş Melike , Kantoǧlu Ömer 
Published: May 2004

AbstractpH‐sensitive poly(acrylamide‐co‐itaconic acid) [P(AAm/IA)] hydrogels were prepared by radiation induced copolymerization of acrylamide (AAm) and itaconic acid (IA) at various ratios. Swelling and shrinking behaviors of these hydrogels were found greatly dependent on the composition of the hydrogel and pH of the buffer solution. The basic structural parameters of the P(AAm/IA) networks such as the molecular weight between crosslinks (Mc) and polymer–solvent interaction parameter (χ) were also determined using the modified Flory‐Rehner equations. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2586–2594, 2004
Differential scanning calorimetry and thermogravimetric analysis investigation of the thermal properties and degradation of some radiation‐grafted films and membranes
Authors: Brack Hans‐Peter , Ruegg Denise , Bührer Heinrich , Slaski Michal , Alkan Selmiye , Scherer Günther G. 
Published: May 2004

AbstractThe influence of irradiation and grafting on the crystallinity of three base polymers has been investigated with differential scanning calorimetry. Grafting has the largest effect on the base polymer crystallinity and results in a reduction of the crystallinity. The thermal degradation of the base polymers and grafted films has been investigated with thermogravimetric analysis. The extent of the fluorination of the base polymer, the irradiation method, and the graft level all influence the thermal degradation and its activation energy. It is proposed that the variation of the chain lengths of the grafted polystyrene chains is actually a primary underlying factor responsible for the influence of these various parameters on the degradation process. The first results of a comparative thermal analysis of some fuel‐cell membranes are also presented, and the promise and shortcomings of this method are discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2612–2624, 2004
Coping after cancer: Risk perceptions, worry, and health behaviors among colorectal cancer survivors
Authors: Mullens Amy B. , McCaul Kevin D. , Erickson Shannon C. , Sandgren Ann K. 
Published: May 2004

AbstractThis study asks whether the experience of cancer motivates healthy behavior change. Further, we asked whether such changes relate to risk perceptions and worry, as suggested by Leventhal's Parallel Processing Model. Male (n=41) and female (n=40) survivors of colorectal cancer were interviewed 1–14 years after they first completed treatment. Younger age was associated with stronger risk perceptions, more worry, and greater anxiety. Shorter‐term, compared to longer‐term survivors, reported higher risk perceptions and more frequent intrusive thoughts. Greater perceived risk, worry and anxiety correlated positively with intentions to make positive health behavior changes. Overall, these survivors did not report exaggerated risk perceptions, and they were not overly worried or anxious about cancer recurrence. However, low‐level risk perceptions, worry, and anxiety motivated interest in adopting protective health behaviors. Copyright © 2003 John Wiley & Sons, Ltd.
The impact of childhood cancer on the family: a qualitative analysis of strains, resources, and coping behaviors
Authors: Patterson Joän M. , Holm Kristen E. , Gurney James G. 
Published: May 2004

AbstractClinical research has led to tremendous improvements in treatment efficacy for most childhood cancers; overall 5‐year survival is now greater than 75%. Long‐term consequences of cure (i.e. adverse medical and psychosocial effects) have only recently begun to emerge as a primary focus of clinical research, including studies of health‐related quality of life among survivors. Usually lacking in such efforts, however, is consideration of the impact of the cancer experience on the family, and the influence that the family's response to cancer has on quality of life in the child. From this qualitative analysis of seven focus groups with 45 parents of children a year or more out of cancer treatment, we report those aspects of a child's cancer diagnosis, treatment, and recovery that parents perceived as particularly difficult for their family, and the resources and coping behaviors parents perceived as helpful to their family in dealing with and managing the cancer experience. Using the Family Adjustment and Adaptation Response theoretical model to organize the data, the domains of strains and resources were delineated into themes and sub‐themes related to the cancer, child, family, health‐care system, and community. Within a third domain, coping, sub‐themes were identified within the themes of appraisal‐focused, problem‐focused, and emotion‐focused coping behaviors. Integration of this information should serve to improve future studies of health‐related quality of life among children who survive cancer. Copyright © 2003 John Wiley & Sons, Ltd.