bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced reactivity in the ammonolysis of phenyl thiolacetates in aqueous medium
Authors: Rajarathnam D. , Babu J. , Nadar P. Ananthakrishna 
Published: August 2002

AbstractThe ammonolysis of several substituted phenyl thiolacetates is kinetically studied in aqueous medium, 18°C, ionic strength 0.1 M (KCl). By following the leaving groups spectrophotometrically (λmax = 260–410 nm), under excess free ammonia, pseudo‐first‐order rate coefficients (kobs) are obtained. The plots of (kobs − kH) against free ammonia concentration are linear at constant pH. The macroscopic nucleophilic substitution rate coefficients (kN) are obtained as the slopes of these plots and found to be pH‐independent for all the thiolesters. The Brönsted‐type plot (log kN against pKa of leaving groups) and the Hammett plot (log kN against σ values of substituents) obtained for the title reactions of thiolesters are linear with slope values of βlg = −0.34 and ρ = 0.74 respectively. From the magnitude of these values, experimental data, the kinetic law, and the analysis of products, it is deduced that the ammonolysis of thiolesters proceeds through a simple bimolecular nucleophilic substitution pathway with a zwitterionic tetrahedral addition intermediate (T±), whereby its formation is rate‐determining (k1 step). Comparison of this reaction of thiolesters with a similar reaction of analogue oxyesters shows a mechanistic difference. Further, for thiolesters there is a rate enhancement with larger kN values. The change in mechanism and enhanced reactivity observed by substitution of the oxygen atom by sulphur atom on the phenyl moiety are discussed in detail. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 18–26, 2002
Brokering knowledge in organizational networks: The SPN approach
Authors: Burnett S. , Brookes‐Rooney A. , Keogh W. 
Published: August 2002

AbstractOver the last three years (at the time of writing this paper) the upstream oil and gas industry has experienced substantial changes at a structural level due a variety of factors including the low cost of oil, depleting reserves, maturing regions, strong competition, and the high costs for development projects. The growing pressure on organizations to operate more economically has led to the recent spate of cost‐reduction initiatives including acquisitions, strategic alliances, joint ventures and consortia agreements. Senior management are realizing that it is their intangible assets, in the form of knowledge, which provide the key to their continued success and their company policies are seeking to identify and manage their knowledge base more effectively by implementing a range of initiatives addressing behavioural, process and technological issues. This paper illustrates how, through the use of a knowledge broker, a major project was handled to realize the knowledge potential of the individuals and the team. Main outcomes from the ongoing project include the establishment of understanding and buy‐in amongst all the alliance partners to the use of shared measures to align objectives, the development of a management structure to support the performance management system and the maintenance of pace and focus through the provision of dedicated resources. Copyright © 2002 John Wiley & Sons, Ltd.
Integrated assessment of catchment suspended sediment budgets: a Zambian example
Authors: Walling D. E. , Collins A. L. , Sichingabula H. M. , Leeks G. J. L. 
Published: August 2002

AbstractIn many developing countries, the management of sediment‐related environmental problems is severely hampered by a lack of information on sediment mobilization and delivery in river basins. The sediment budget concept represents a valuable framework for assembling such information, which can, in turn, be used to assist with the design and implementation of soil erosion and sediment control policies. However, the information necessary to construct a catchment sediment budget is difficult to assemble. Against this background, an integrated approach to establishing a catchment suspended sediment budget, involving a river monitoring station, the use of 137Cs measurements to estimate soil erosion and deposition and floodplain accumulation rates within the catchment, and sediment source fingerprinting, has been developed and tested in the 63 km2 catchment of the upper Kaleya River in southern Zambia. The approach developed not only provides detailed information on individual components of the suspended sediment delivery system, but also permits the establishment of the overall catchment sediment budget. A sediment budget for the upper Kaleya catchment is presented and both its key features and its wider implications for catchment management are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Soil degradation by erosion
Authors: Lal R. 
Published: August 2002

AbstractSoil degradation by accelerated erosion is a serious problem and will remain so during the 21st century, especially in developing countries of the tropics and subtropics. Yet, its extent, severity, and economic and environmental impacts are debatable. Estimates of global and regional land area affected are tentative and subjective. Results of field measurements are often technique‐dependent. Considerable progress has been made in modeling soil erosion, yet field validation of these models remains to be done for principal soils and ecoregions. Similar to the land area affected, estimates of erosional impacts on crop yield, productivity and soil quality are tentative and subjective. Further, erosion‐induced losses on crop yield are scale‐dependent because of the compensatory beneficial effects on yields from depositional sites, and technology‐dependent because of the masking effects of input such as fertilizers and irrigation. Erosion caused changes in soil carbon dynamics and non‐point source water pollution are important environmental impacts. While erosion (e.g., detachment and transport) can lead to emission of trace gases into the atmosphere, deposition can bury and sequester some of the carbon. In addition to improving the database on the land area affected, there is also a need to assess erosional impacts on productivity and soil C balance at the watershed, regional, and global scale. Copyright © 2001 John Wiley & Sons, Ltd.
Photodynamic therapy of vulvar and vaginal condyloma and intraepithelial neoplasia using topically applied 5‐aminolevulinic acid*
Authors: Fehr Mathias K. , Hornung René , Degen Andrea , Schwarz Viola A. , Fink Daniel , Haller Urs , Wyss Pius 
Published: August 2002

AbstractBackground and ObjectivesTo determine the feasibility of photodynamic therapy (PDT) of vulvar and vaginal condyloma and intraepithelial neoplasia (VIN, VAIN) and to compare PDT results with conventional treatments.Study Design/Materials and MethodsThirty‐eight patients with vulvar or vaginal intraepithelial neoplasia (VIN) grade II/III (n = 22) or condyloma (n = 16) had 10% 5‐aminolevulinic acid (ALA)‐gel applied topically. After 2–4 hours, 80–125 J/cm2 laser light at a wavelength of 635 nm was applied. PDT was compared to conventional treatments for condyloma (CO2 laser evaporation) and for VIN III (laser evaporation, surgical excision).ResultsThe complete clearance rate for condyloma treated by PDT was 66% and the rate for IN was 57% (as determined by biopsy). Of the neoplasia patients, none with hyperkeratotic VIN (n = 4) responded, and only one of four with increased pigmentation cleared. No scarring occurred, and postoperative discomfort lasted 4.9 ± 3.4 days. Reduced disease‐free survival (DFS) was associated with multifocal VIN (P = 0.02, OR 2.17, 95% CI 1.15–4.08), but DFS did not vary with treatment mode.ConclusionsAlthough PDT is not equally efficacious for all subgroups, PDT for condyloma and intraepithelial neoplasia appears to be as effective as conventional treatments, but with shorter healing time and excellent cosmetic results. Lasers Surg. Med. 30:273–279, 2002. © 2002 Wiley‐Liss, Inc.
Continuous changes in the optical properties of liver tissue during laser‐induced interstitial thermotherapy
Authors: Ritz Joerg P. , Roggan Andre , Germer Christoph T. , Isbert Christoph , Müller Gerhard , Buhr Heinz J. 
Published: August 2002

AbstractBackground and ObjectiveLaser‐induced thermotherapy (LITT) is a promising treatment for irresectable liver tumors. To predict the effects of laser applications and to optimize treatment planning in LITT, it is essential to gain knowledge about light distribution in tissue, tissue optical properties (absorption, scattering, anisotropy, penetration depth), and their continuous changes during therapy.Study Design/Materials and MethodsMeasurements of optical properties were performed with a double integrating‐sphere system and a laser diode (830 nm). Porcine liver tissue samples were examined in a native state (35°C) and after exposure to different temperatures (45°C to 80°C).ResultsRising temperature was accompanied by a decrease in the absorption coefficient and anisotropy factor and an increase in the scattering coefficient. These changes were only significant in the temperature range of 50° to 65°C (P < 0.01). The optical penetration depth decreased from 3.1mm in the native state to 1.7mm at 65°C (P < 0.01). Above 65°, there was no significant change in the tissue optical properties.ConclusionsThe optical properties of liver tissue change significantly under the influence of tissue heating, resulting in a decreased optical penetration depth. These changes occur mainly in the temperature range of 50°C to 65°C, corresponding to protein denaturation. To ensure a safe and effective procedure, an adjustment of the laser power to the actual penetration depth is recommended during therapy. Lasers Surg. Lasers Surg. Med. 28:307–312, 2001. © 2001 Wiley‐Liss, Inc.
Fluorescent imaging in a glioma model in vivo
Authors: Nikas Dimitrios C. , Foley James W. , Black Peter M. 
Published: August 2002

AbstractBackground and ObjectiveNile blue dyes have been shown to have affinity for tumor tissue as compared to surrounding normal tissue and to be relatively non‐toxic. We have employed EtNBA, a lipophilic, fluorescent benzophenoxazine dye, in a murine model to image subcutaneous and intracranial U‐87 glioma implants.Study Design/Materials and MethodsThe imaging system used to detect fluorescence consists of a SIT video camera fitted with a zoom microscope‐magnifying lens. The tumor was illuminated with a 632.8‐nm diffuse beam from a helium–neon laser. The video image was processed using a Sony image processor to give real‐time pseudocolor and enhanced black and white images.ResultsFollowing subcutaneous injection of the dye at doses of 2.5–5.0 mg/kg bw, we observed a gradual increase of the fluorescent signal from the tumor which peaked 1–3 hours post‐injection with variable selectivity (typically 4:1) for tumor to normal surrounding tissues permitting the clear demarcation of the tumor.ConclusionsThe present in vivo study demonstrates that EtNBA is a safe and effective photodiagnostic agent, able to demarcate U87‐MG solid tumors in mice on a real‐time basis at a concentration of 2.5–5.0 mg/kg 1–3 hours after administration. Lasers Surg. Med. 29:11–17, 2001. © 2001 Wiley‐Liss, Inc.
Comparison of the methylene blue and toluidine blue photobactericidal efficacy against gram‐positive and gram‐negative microorganisms
Authors: Usacheva Marina N. , Teichert Matthew C. , Biel Merrill A. 
Published: August 2002

AbstractBackground and Objective:Studies on the photobactericidal efficacy of methylene blue (MB) and toluidine blue (TB) have shown inconsistent results in the literature. This study evaluated the bactericidal efficacy of MB and TB against different bacteria under light and dark conditions to determine the most effective bactericidal dye.Study Design/Materials and Methods:Suspensions of Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, Hemophilus influenzae, Escherichia coli, and Pseudomonas aeruginosa in saline were treated in dark and red laser light conditions in the presence of each dye using an argon pumped‐dye and a diode laser emitting light at 630 and 664 nm, respectively. The effect of dye concentration, dark incubation time, the fluence and intensity of laser light on the destruction of different bacteria were compared.Results:Both dyes eradicated all examined bacteria under laser light. The complete photodestruction of microorganisms was reached at TB concentrations of 1.5–7‐fold less than that of MB.Conclusion:TB exhibits a greater bactericidal activity than MB against most bacteria in dark and light conditions. Mostly, these results are consistent with their respective dye partition coefficients. Lasers Surg. Med. 29:165–173, 2001. © 2001 Wiley‐Liss, Inc.
Matrilysin (matrix metalloproteinase‐7) expression in ulcerative colitis–related tumorigenesis†
Authors: Newell Ken J. , Matrisian Lynn M. , Driman David K. 
Published: August 2002

AbstractMatrilysin (matrix metalloproteinase‐7) plays a part in the initiation and growth of colorectal tumors; expression of this protein has been implicated in tumor invasion and metastasis. To date, matrilysin expression in ulcerative colitis (UC)–associated tumorigenesis has not been studied. The aim of this study was to assess the immunohistochemical expression of matrilysin at different stages of UC‐associated neoplasia. Paraffin‐embedded specimens from 25 patients with UC without dysplasia, UC‐related low‐grade dysplasia (LGD) and high‐grade dysplasia (HGD), and UC‐associated carcinoma as well as four colon biopsy samples with no abnormality were examined using an anti–human matrilysin monoclonal antibody and standard immunoperoxidase techniques. Matrilysin expression was recorded as the number of positive cases and the percentage of positive crypts as follows: normal: none of four; negative results for dysplasia: seven of 12 (< 10%); LGD: nine of 15 (< 10%); HGD: nine of 13 (11–50%); and invasive carcinoma: six of seven (> 50%). The results indicated an apparent switch from focal expression of matrilysin in UC‐related low‐grade dysplasia to widespread expression in high‐grade dysplasia and invasive cancer, mimicking the pattern of expression in sporadic colorectal cancer. Although the sample size is small and further investigation therefore is required, the results suggest the possible role of anti–matrix metalloproteinase therapy in reducing the risk of progression from LGD to cancer in patients with ulcerative colitis. Published 2002 Wiley‐Liss, Inc.
Comparative analysis of loss of heterozygosity of specific chromosome 3, 13, 17, and X loci and TP53 mutations in human epithelial ovarian cancer
Authors: Manderson Emily N. , Presneau Nadège , Provencher Diane , Mes‐Masson Anne‐Marie , Tonin Patricia N. 
Published: August 2002

AbstractWe previously reported the identification of three minimal regions of deletion on the short arm of chromosome 3 (3p) in epithelial ovarian tumor specimens, suggesting that the inactivation of tumor‐suppressor genes in these regions may be important in terms of ovarian tumorigenesis. Another previous study of ovarian cancer observed that allele loss of chromosome 179 was frequently found in ovarian tumors that also showed loss of heterozygosity (LOH) of chromosomes 3p, 13q, 17p, and Xp. In an independent study, we also reported a high frequency of LOH for selected chromosome 17 loci in high‐grade and late‐stage ovarian tumors. We have extended our LOH analysis of chromosome 3p to include 102 ovarian tumor specimens (29 and 73 samples were previously examined for LOH of chromosome 3p and 17 markers, respectively), using additional polymorphic markers, to assess the coordinate LOH of loci representing the three chromosome 3p minimal regions of deletions [von Hippel–Lindau syndrome (VHL), thyroid hormone receptor beta, and fragile histidine triad (FHIT)] and LOH of other important loci [tumor protein 53 (TP53), breast cancer 1 early onset (BRCA1), breast cancer 2 early onset, retinoblastoma 1, ornithine carbamoyltransferase, and androgen receptor] or somatic mutations in TP53. There was a significant association between LOH of any chromosome 3p marker and LOH of any chromosome 17 marker (P = 0.026). The frequency of LOH at the TP53 locus was higher in the group of samples that displayed LOH of a 3p marker (P = 0.019), as was the frequency of LOH at the BRCA1 locus (P = 0.014). LOH of chromosome 3p was noted in four specimens that did not display LOH of either the BRCA1 or the TP53 locus, indicating that LOH of these loci need not precede LOH of the chromosome 3p loci. We found a significant association between LOH of the VHL (3p25) locus and LOH of any chromosome 17 marker (P = 0.005), suggesting that there may be an important relationship, in the tumorigenesis of epithelial ovarian cancer, between a gene at 3p25 and a gene located on chromosome 17. Our results indicate that inactivation of p53 by somatic mutation is unlikely to be a prerequisite to chromosome 3p LOH, because we found no significant association between mutations in TP53 and LOH of the three chromosome 3p loci. The frequency of LOH at the FHIT locus at 3p14 increased significantly with advancing age at diagnosis (P = 0.018), as did the frequency of somatic TP53 mutations (P = 0.008). © 2002 Wiley‐Liss, Inc.
Oxidative DNA damage and 8‐hydroxy‐2‐deoxyguanosine DNA glycosylase/apurinic lyase in human breast cancer
Authors: Li Donghui , Zhang Weiqing , Zhu Jijiang , Chang Ping , Sahin Aysegul , Singletary Eva , Bondy Melissa , Hazra Tapas , Mitra Sankar , Lau Serrine S. , Shen Jianjun , DiGiovanni John 
Published: August 2002

AbstractTo test the hypothesis that oxidative stress is involved in breast cancer, we compared the levels of 8‐hydroxy‐2‐deoxyguanosine (8‐oxo‐dG), an oxidized DNA base common in cells undergoing oxidative stress, in normal breast tissues from women with or without breast cancer. We found that breast cancer patients (N = 76) had a significantly higher level of 8‐oxo‐dG than control subjects (N = 49). The mean ( ± SD) values of 8‐oxo‐dG/105 dG, as measured by high‐performance liquid chromatography electrochemical detection, were 10.7 ± 15.5 and 6.3 ± 6.8 for cases and controls, respectively (P = 0.035). This difference also was found by immunohistochemistry with double‐fluorescence labeling and laser‐scanning cytometry. The average ratios (×106) of the signal intensity of antibody staining to that of DNA content were 3.9 ± 7.2 and 1.1 ± 1.4 for cases (N = 57) and controls (N = 34), respectively (P =  0.008). There was no correlation between the ages of the study subjects and the levels of 8‐oxo‐dG. Cases also had a significantly higher level of 8‐hydroxy‐2‐deoxyguanosine DNA glycosylase/apurinic lyase (hOGG1) protein expression in normal breast tissues than controls (P = 0.008). There was no significant correlation between hOGG1 expression and 8‐oxo‐dG. Polymorphism of the hOGG1 gene was very rare in this study population. The previously reported exon 1 polymorphism and two novel mutations of the hOGG1 gene were found in three of 168 cases and two of 55 controls. In conclusion, normal breast tissues from cancer patients had a significantly higher level of oxidative DNA damage. The elevated level of 8‐oxo‐dG in cancer patients was not related to age or to deficiency of the hOGG1 repair gene. © 2001 Wiley‐Liss, Inc.
Core promoter involvement in the induction of rat ornithine decarboxylase by phorbol esters
Authors: Zhao Biwei , Butler Andrew P. 
Published: August 2002

AbstractOverexpression of ornithine decarboxylase (ODC) is an important oncogenic event in tumorigenesis. Although ODC was one of the first genes described whose product is inducible by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), the mechanisms of ODC transcriptional regulation have remained elusive. In this study, we systematically analyzed the rat ODC core promoter region for novel TPA response elements. Analysis of linker scanning mutants of the ODC promoter from the TATA box to the transcription start site demonstrated that mutation of the TATA box reduced the TPA induction ratio by 40%, while the basal ODC promoter activity was not significantly changed. A novel region between nt − 20 to − 10 was shown to be critical for both basal promoter activity and induction by TPA. Random mutagenesis of this region showed that conversion of the GC‐rich wild‐type sequence into a T‐rich sequence could either substantially increase the basal promoter activity and decrease the TPA induction ratio or dramatically reduce the basal promoter activity, depending on the T content. Mutant R5, containing an ATTT sequence at nt − 15 to − 12, caused a more than twofold increase of basal promoter activity and 80% reduction of TPA induction ratio. We suggest that this region interacts with components of the general transcription machinery and that the strength of this interaction is mediated by the T‐content in this region. © 2001 Wiley‐Liss, Inc.
The feasibility of regulating gambling on the Internet
Authors: Clarke Roger , Dempsey Gillian 
Published: August 2002

AbstractInternet gambling presents substantial new challenges to governments and regulatory agencies. Existing approaches to betting, lotteries and gaming are limited by the nature of Internet technology, and the international nature of the activity. Particular aspects of Internet gambling are considered, and the conclusion is reached that prohibition is an ineffectual alternative, and that licensing of gambling services providers is the appropriate approach. Copyright © 2001 John Wiley & Sons, Ltd.
On the benefits of collaboration: consumer psychology, behavioral economics and relational frame theory
Authors: Quiñones Rene , Hayes Linda J. , Hayes Steven C. 
Published: August 2002

AbstractConsumer behavior is a pervasive feature of the human circumstance, and its study has long been pursued by behaviorally oriented psychologists, among whom may be counted John B. Watson. Relatively few behaviorists have addressed these issues, however, with the result that the field of consumer behavior is crippled by dualistic propositions and weak methodologies (Foxall GR. 1992. The consumer situation: an integrative model for research in marketing. Journal of Marketing Management 8: 383–404; 1998. Radical behaviorist interpretation: generating and evaluating an account of consumer behavior. The Behavior Analyst 21: 321–354). As such, the field is ready for a reformulation of its basic premises and the adoption of more rigorous, experimental procedures. Copyright © 2000 John Wiley & Sons, Ltd.