Search Results - (Author, Cooperation:D. Lawrence)

2018-01-19

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Sociology

2018-01-12

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Physics

2018-06-19

The American Association of Immunologists (AAI)

0022-1767

1550-6606

Medicine

2014-10-11

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Carcinogens/toxicity ; Carcinoma, Non-Small-Cell Lung/chemically induced/*diagnosis/*genetics ; Cytidine Deaminase/genetics ; Evolution, Molecular ; Gene Dosage ; *Genetic Heterogeneity ; *Genomic Instability ; Humans ; Lung Neoplasms/chemically induced/*diagnosis/*genetics ; Mutation ; Neoplasm Recurrence, Local/genetics ; Prognosis ; Smoking/adverse effects ; Translocation, Genetic ; Tumor Cells, Cultured

1475-682X

Blackwell Publishing Journal Backfiles 1879-2005

Sociology

Electronic Resource

1468-2885

Blackwell Publishing Journal Backfiles 1879-2005

Media Resources and Communication Sciences, Journalism

Psychology

This article derives a set of hypotheses to explain how drama can affect the behavior of the audience. First, theories of drama explain how to create a drama that involves the audience. Second, drama theory explains how confrontation leads to emotional response, cognitive reorientation, and character change within a drama, both fictional and real. A convergence theory of communication predicts that audience members who perceive the change in characters with whom they closely identify will be influenced to change their behavior. Cognitive image mapping is used to illustrate how these hypotheses could be tested with an entertainment—education drama about AIDS in Africa.

Electronic Resource

1442-1984

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Abstract Annual plants make up ca. 50% of local floras in the Sonoran Desert. As with most plant communities, there is no shortage of potential coexistence generating mechanisms, and several mechanisms are likely contributors to coexistence at different spatial scales in the Sonoran Desert, e.g. spatial heterogeneity and the behaviors of predators and grazers. We explore one mechanism of likely importance for desert annuals: temporal environmental variation. It is widely recognized that coexistence is promoted by temporal variation if species such as desert annuals have “temporal niches” in the sense that each has years in which it out-performs the others. It is usually suggested that some resistent life-history stage, such as a seed bank, is also necessary to buffer each species from the negative population dynamic impact of unfavorable years. Using ten years of demographic data, we document the large year-to-year variation in population dynamics of desert annuals and show that ten species respond differently to temporal variation. Competition experiments document reversals in competitive superiority. Also, all species have a between-year seed bank, such that only a proportion of the seed bank germinates in any given year. Thus this system meets our intuitive requirements for variance-based coexistence. Dynamic models of this system demonstrate that subtle aspects of the species biology determine whether coexistence criteria are actually met. Specifically, variable germination fractions are required and coexistence is most readily favored with “predictive” germination. Germination fractions in this system do vary among years in a species specific fashion. Also, for the three years of available data, germination was predictive, in that each species had greater germination fractions in year of greater demographic success. Thus all of the population dynamic elements necessary for temporal variance mediated coexistence seem to be present in this system.

Electronic Resource

0044-118X

Psychology

Sociology

0022-0671

Education

1530-0358

Rectal neoplasms ; Colorectal neoplasms ; Drug therapy ; Radiotherapy ; Surgery ; Combined modality therapy ; Clinical trials

Springer Online Journal Archives 1860-2000

Medicine

Abstract PURPOSE: National Surgical Adjuvant Breast and Bowel Project Protocol R-03 was designed to determine the worth of preoperative chemotherapy and radiation therapy in the management of operable rectal cancer. METHODS: Thus far, 116 patients of an eventual 900 with primary operable rectal cancer have been randomized to receive multimodality therapy to begin preoperatively (59 patients) or identical therapy beginning after curative surgery (57). All patients received seven cycles of 5-fluorouracil (FU)/leucovorin (LV) chemotherapy. Cycles 1 and 4 through 7 used a high-dose weekly FU regimen. In Cycles 2 and 3, FU and low-dose LV chemotherapy was given during the first and fifth week of radiation therapy (5,040 cGy). The preoperative arm (Group 1) received the first three cycles of chemotherapy and all radiation therapy before surgery. The postoperative arm (Group 2) received all radiation and chemotherapy after surgery. Primary study end points included disease-free survival and survival. Secondary end points included local recurrence, primary tumor response to combination therapy, tumor downstaging, and sphincter preservation. RESULTS: Overall treatment-related toxicity was similar in both groups. Although seven preoperative patients had events after randomization that precluded surgery, eight events occurred during an equivalent follow-up period in the postoperative group. No patient was deemed inoperable because of progressive local disease. Sphincter-saving surgery was intended in 31 percent of Group 1 patients and 33 percent of Group 2 patients at the time of randomization. Such surgery was actually performed in 50 percent of the preoperatively treated patients and 33 percent of the postoperatively treated patients. The use of protective colostomy in patients undergoing sphincter-sparing surgery and the development of perioperative complications in all surgical patients were similar in both groups. There was evidence of tumor downstaging in evaluable patients under-going preoperative therapy, with 8 percent of Group 1 patients having had a pathologic complete response. CONCLUSION: These data do suggest that the preoperative chemotherapy and radiation therapy regimen used are, at least, as safe and tolerable as standard postoperative treatment. There is presently a trend to tumor downstaging and sphincter preservation in the preoperative arm. Whether this arm will have greater or lesser survival and long-term toxicity awaits the completion of this relevant study.

Electronic Resource

1432-1939

Springer Online Journal Archives 1860-2000

Biology

Summary A model is developed to consider the interplay between dispersibility and delayed germination in desert annuals. The model explores the effect of low levels of dispersal, considered realistic for annual plants, on optimal germination fraction. The model also demonstrates the effect of the amount and accuracy of “predictive” (responsive to the environment) dormancy on the optimal innate germination fraction (not responsive to environmental conditions). Optimal germination fraction is found to be very sensitive to changes in despersibility especially at the limited dispersibilities that are realistic for annual plants. As dispersibility increases, optimal germination fraction increases. If plants make two kinds of seeds with differing despersibility, reproduction is maximized if the low dispersal seeds have delayed germination and the high dispersal seeds have quick germination. If dormancy mechanisms permit seeds to germinate when environmental conditions allow successful maturation, and remain dormant when environmental conditions do not permit successful maturation, what fraction of seeds should remain dormant under predicted good conditions as a hedge against inaccurate prediction of the environment? If environmental cues that break dormancy are uncorrelated with environmental conditions that permit successful maturation, predictive dormancy has little or no effect on the optimal innate germination fraction. When predictive dormancy lowers the probability of germinating when environmental conditions preclude successful maturation, the optimal innate germination fraction increases with increasing germination control by predictive dormancy. With a moderate degree of germination control by predictive dormancy, the optimal innate dormancy is still sensitive to changes in dispersal in the low dispersal ranges characteristic of annual plants. Evidence is presented from plant species that have both dispersal and germination dimorphisms to support the predicted correlation of high germination fractions with high dispersal.

Electronic Resource

1432-2161

Magnetic resonance imaging ; Bone neoplasms ; Chondroblastoma ; Clear cell chondrosarcoma ; Iliopsoas bursa

Springer Online Journal Archives 1860-2000

Medicine

Abstract Three cases of lytic, calcified epiphyseal lesions with plain film and computed tomography features suggestive of chondroblastoma were imaged by magnetic resonance imaging. Histopathologic correlation was obtained in each case. Two cases of chondroblastoma showed low signal intensity on both short (TR600/TE20ms) and long (TR2500/TE80ms) spin echo (SE) images. The third case, a clear cell chondrosarcoma, demonstrated increased signal intensity on moderately T2 weighted (TR2500/TE40ms) images. These findings suggest that magnetic resonance imaging may be helpful in distinguishing these lesions.

Electronic Resource

1432-2161

Disc ; Disc disease ; Disc extrusion ; Magnetic resonance imaging

Springer Online Journal Archives 1860-2000

Medicine

Abstract Magnetic resonance (MR) imaging is useful in evaluating a variety of spinal pathologies including intervertebral disc disease. Herniated discs are commonly believed to undergo premature degeneration and produce low intensity signal on T2-weighted images. We reviewed 154 patients who were studied for disc herniations or other pathology. Fifty-nine (38%) had disc herniations and 7 of these (5%) had a fragment that was hyperintense with respect to the adjacent intervertebral disc on T2-weighted images. It is hypothesized that some disc fragments may contain a higher water content that causes prolongation of the T2 signal. The bright signal which is therefore seen on long TR long TE (T2-weighted) images may be a useful sign suggesting herniation or extrusion.

Electronic Resource

1615-6110

Angiosperms ; Compositae ; Dispersal ; pappus ; growth form: annuals ; biennials ; perennial herbs ; shrubs and trees ; weeds and non-weeds

Springer Online Journal Archives 1860-2000

Biology

Abstract The relationship between gross morphological dispersal structures, growth habit, and weediness is reported for a worldwide sample of 5893 Compositae species from 18 regional floras. A significantly smaller percentage of annual species than perennial species has dispersal structures. Among species with dispersal structures, plumed types are more frequent in perennials while adhesive types are more frequent in annuals. Differences in the occurrence and nature of dispersal structures between perennial herbs, shrubs and trees were minor. Weeds are less likely to have well developed morphological dispersal structures than non-weeds. The data support the idea that dispersal in space may be more important for perennial or non-weedy plants than for annual and weedy plants.

Electronic Resource

1573-7845

Springer Online Journal Archives 1860-2000

Sociology

Electronic Resource

1573-7845

Springer Online Journal Archives 1860-2000

Sociology

Electronic Resource

1573-7217

adjuvant chemotherapy ; breast cancer ; estrogen receptor ; progesterone receptor

Springer Online Journal Archives 1860-2000

Medicine

Summary In 1977 the National Surgical Adjuvant Breast and Bowel Project (NSABP) initiated a prospectively randomized clinical trial to evaluate the relative merits of 1-phenylalanine mustard and 5-fluorouracil (PF) with and without tamoxifen (T) as adjuvant therapy for patients with primary breast cancer and positive axillary nodes. A previous presentation of findings noted that there was a strong relationship between the outcome of those receiving PFT and the estrogen receptor (ER) and progesterone receptor (PR) content of their tumors. This report relates the outcome of the PF-treated patients in that trial with these tumor receptors. It indicates that the results observed following nonhormonal therapy (PF) are also related to tumor receptors. Both the disease-free survival (DFS) and survival (S) of women following PF therapy were influenced by the ER and PR content of their tumors. Subsequent to adjustment for other prognostic variables, the predictive influence of tumor ER persisted. Both the DFS (p = 0.0003) and the S (p = 0.00003) were significantly higher in those with ≥ 10 fmol tumor ER than in those with 〈 10 fmol ER. The PR significantly added to the predictive value of ER. Thus, this analysis is the first to demonstrate that having information on both ER and PR is important for predicting outcome of patients receiving adjuvant chemotherapy. The study does not provide information which correlates receptor status with the response of patients to adjuvant chemotherapy since there is no similar nonchemotherapy-treated group of patients in the trial. The findings continue to emphasize that there is a heterogeneity in outcome of breast cancer patients to adjuvant chemotherapy which is related to an increasing number of host and tumor variables. For proper assessment of overall results, it is essential that analyses employ tests for interaction to indicate homogeneity or heterogeneity of patient subsets and that adjustments be made for imbalances in tumor ER and PR as well as in other prognostic factors.

Electronic Resource

1573-1561

Bursera ; Burseraceae ; Blepharida ; Chrysomelidae ; monoterpenes ; chemical defense ; fecal shield ; insect defense

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Abstract The genus Bursera produces resin stored in canals in the leaf. When leaves are damaged, some, but not all, species release abundant resin. Species of Blepharida are specialized herbivores of Bursera, and they exhibit variation in their counterdefensive behavior. Species feeding on resin-releasing plants cut the leaf veins before feeding, which often makes them more prone to predation. They also adorn their backs with their feces and may regurgitate and release an anal secretion when attacked or disturbed by predators. Species that feed on Bursera species that release no fluids do not sever the leaf veins prior to feeding, and they do not carry their feces on their backs. Instead, they face their predators, raise their heads in a "boxing-like" display, and rapidly swing their abdomens from side to side. We performed a comparative chemical analysis of the compounds found in Bursera schlechtendalii, a species that releases abundant resins, and B. biflora, a species that does not. We also analyzed the frass, enteric discharges, and larvae of the two species of Blepharida that feed on each of these plants. The compounds found in the body, feces, and discharges of the Blepharida species that adorns itself with feces match the chemical mixture of its host plant, suggesting that this beetle species can compensate its higher risk of predation by using the compounds present in the plant for defense. The chemical mixture of B. biflora is more complex and does not match the compounds found in the body or frass of its beetle herbivore, suggesting that the defensive strategy of this insect is behavioral and does not rely on its host's constituents.

Electronic Resource

0749-1581

EPR ; Free radicals ; ENDOR ; Deuterated spin traps ; High resolution ; Chemistry ; Analytical Chemistry and Spectroscopy

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

Deuterated analogues of C-phenyl N-tert-butyl nitrone (PBN) were synthesized to provide significant gains in spectral sensitivity and resolution in electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) applications. Three deuterated α-phenyl N-tert-butyl nitrones (PBNs) were prepared. EPR spectra of the corresponding radical spin adducts with the phenyl ring (PBN-d5-R·) or tert-butyl moiety (PBN-d9-R·) deuterated were found to enhance disclosure of the structure of the added radical. The most dramatic increases in EPR resolution, however, were not realized until both the phenyl and tert-butyl groups were deuterated (PBN-d14-R·). Here, baseline resolution of unique long-range (e.g. γ- and δ-) hyperfine splittings from the radical addend could be displayed. Representative radical spin adducts of PBN-d14 (methyl, hydroxyl, aminyl, cyanyl, carbamoyl, and vinyl) were prepared and compared with those of PBN to illustrate this point. It is also shown that when even higher spin adduct resolution is desired the combination of spin trap deuteration and ENDOR may be applied to advantage.

6 Ill.

Electronic Resource

0749-1581

electron paramagnetic resonance ; NMR ; 1H ; 14N ; 13C hyperfine splittings ; Spin traps ; Spin adducts ; Nitrones (1-pyrroline-N-oxides) ; Chemistry ; Analytical Chemistry and Spectroscopy

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

Ten substituted 5,5-dimethyl-1-pyrroline-N-oxides as well as the parent nitrene spin trap (DMPO) were prepared: 5,5-dimethyl-1-pyrroline-N-oxide, 2,5,5-trimethyl-1-pyrroline-N-oxide, 2-tert-butyl-5,5-dimethyl-1-pyrroline-N-oxide, 2-phenyl-5,5-dimethyl-1-pyrroline-N-oxide, 2-d5-phenyl-5,5-dimethyl-1-pyrroline-N-oxide, 2-phenyl-5,5-dimethyl-1-pyrroline-N-oxide-nitronyl-13 C, 2-(4-fluorophenyl)-5,5-dimethyl-1-pyrroline-N-oxide, 2-(4-chlorophenyl)-5,5-dimethyl-1-pyrroline-N-oxide, 2-(4-tert-butylphenyl)-5,5-dimethyl-1-pyrroline-N-oxide, 2-(4-methylphenyl-5,5-dimethyl-1-pyrroline-N-oxide) and 2-(2- methylphenyl)-5,5-dimethyl-1-pyrroline-N-oxide. Analytical (i.e. EPR-grade) samples of these novel cyclic nitrones were obtained and characterized by (among other methods) 1H NMR spectroscopy. Reduction of DMPO and these various 2-substituted cyclic nitrones gave the corresponding cyclic N,N-dialkylhydroxylamines, whose structures and conformations were also analyzed by 1H NMR spectroscopy. Air oxidation of these cyclic N,N-dialkylhydroxylamines provided access to the EPR spectra of the hydrogen, methyl, tert-butyl, phenyl, d5-phenyl, nitronyl-13C-phenyl, 4-fluorophenyl, 4-chlorophenyl, 4-tert-butylphenyl, 4-methylphenyl and 2-methylphenyl cyclic aminoxyl (pyrrolidine N-oxyl nitroxide) radical spin adducts of DMPO. The 14N, 13C (where applicable) and 1H hyperfine splitting constants of these aminoxyl adducts in ten solvents of widely different polarities (e.g., hexane to water) were measured and the solvent effect on these parameters was evaluated. It was found that for the various 2-substituted DMPO-type spin adducts both the nitrogen and β-hydrogen EPR hyperfine splittings correlated linearly (r2 ≥ 0.90) with typical solvent polarity parameters such as ET(30). The correlation between the nitrogen and β-hydrogen hyperfine splitting constants were even more linear (r2 ≥ 0.97).

4 Ill.

Electronic Resource