bluuebunny/crossref_metadata_2025 huggingface dataset:
Pseudomonas syringaepv.tagetis(PST) population dynamics both on and in Canada thistle (Cirsium arvense) leaves as affected by rain events
Authors: Tichich Ryan P. , Doll Jerry D. , McManus Patricia S.
Published: September 2006

Field trials were conducted to evaluate the season long population dynamics and location (in leaf or on leaf surface) of an antibiotic resistant strain of the bacteriumPseudomonas syringaepv.tagetis(PST) applied to Canada thistle leaves. An application preceding 2 to 3 d of hot dry weather was compared to an application preceding 2 to 3 d of cool wet weather. Leaf samples were taken weekly to assess the population of PST found inside the leaves and on the leaf surface. While PST populations initially differed, populations were similar for both treatments one week after application. While this suggests that environment did not have a major impact, weather conditions for testing this hypothesis were not ideal. Over the first 35 d of the experiment, little rainfall was observed. PST populations were low and stable. However, rain events over the 40 d that followed resulted in great oscillations in mean PST populations and in some cases significant population increases. During dry periods, internal and total PST populations differed significantly, suggesting the external populations played a major part in population composition. However, the two sampling periods that closely followed three consecutive days of rainfall indicated internal populations were not significantly different from the total, suggesting that internal populations played the primary role in population composition. The results of this research provide evidence that rain events lead to overall PST population increases and to greater proportions of PST inside Canada thistle leaves, suggesting that it is better to apply PST during wet periods than dry.
Altered weed reproduction and maternal effects under low-nitrogen fertility
Authors: Tungate Kimberly D. , Burton Michael G. , Susko David J. , Sermons Shannon M. , Rufty Thomas W.
Published: September 2006

The low-nitrogen status of highly weathered soils may offer a potential alternative for weed suppression in agricultural systems with N2-fixing crops. In this study, we used sicklepod as a model to evaluate weed response that might occur with managed reductions in nitrogen-soil fertility. A field study was conducted with the parental generation supplied 0, 112, 224, or 448 kg N ha−1. Decreased nitrogen fertility led to reduced shoot biomass, seed number, and total seed mass. Individual seed mass was lower, but seed % nitrogen was not affected. Analysis of seed-mass distribution confirmed that low parental fertility was associated with more small seeds as a proportion of total seeds produced. Additional experiments in hydroponics culture revealed slower growth rates of seedlings produced from small seeds when grown under low-nitrogen conditions. Competitiveness of plants from small (low nitrogen) and large (high nitrogen) seed classes was determined in a replacement-series experiment conducted in sand culture in a controlled environment at two densities and two levels of nitrogen nutrition. Plants produced from smaller seeds were less competitive in low-nitrogen fertility conditions, but plants from small and large seeds competed similarly when grown under high-nitrogen fertility. The results support the hypothesis that comprehensive management strategies to reduce nitrogen availability for weed growth in low-fertility conditions could decrease weed interference by decreasing growth and seed production of parental plants and through maternal effects that lower competitiveness of offspring.
Measuring community shifts in a weed seedbank study with the use of distance-based redundancy analysis
Authors: Reberg-Horton Chris , Gallandt Eric R. , Molloy Tom
Published: September 2006

Distance-based redundancy analysis (db-RDA), a recently developed ordination technique useful for both multivariate hypothesis testing and data interpretation, was used to evaluate treatment effects on weed communities in a long-term study of alternative potato cropping systems. The experiment consisted of a factorial arrangement of three pest management systems, conventional (CON), reduced input (RI), and biointensive (BIO), two soil management systems (amended vs. unamended), and two crop-rotation entry points. Soil samples collected in the spring of 1998 were subjected to exhaustive germination as a means of characterizing the weed community. Using partial ordinations, each factor in the factorial treatment structure was tested separately, revealing a significant interaction between pest and soil management systems. An ordination diagram of the pest by soil management interaction was used to interpret the results. Weed species that were highly correlated with the first two ordination axes included: common lambsquarters, broadleaf plantain, oakleaf goosefoot, common hempnettle and a complex of the Brassicaceae that included wild mustard, birdsrape mustard, and wild radish. Univariate analyses confirmed the response of these species to the factors examined. The BIO pest management system showed a different response to soil amendments than the other systems. Soil amendments caused an increase in the total weed density in the CON and RI systems, but caused a decrease in the BIO system. Given the need for better multivariate hypothesis testing and data interpretation in many types of weed science research, the use of db-RDA is expected to grow.
Imazamox application timing for small broomrape (Orobanche minor) control in red clover
Authors: Eizenberg Hanan , Colquhoun Jed B. , Mallory-Smith Carol A.
Published: September 2006

Broomrapes (Orobanche spp.) are chlorophyll-lacking root parasites of many dicotyledonous species and cause severe damage to vegetable and field crops from several botanic families such as Fabaceae, Solanaceae, Compositae, and Umbelliferae. In Oregon, small broomrape has been identified as a parasite of red clover. In Oregon field studies, small broomrape control was excellent when imazamox was applied postemergence to red clover but preemergence to small broomrape. Temperature is one of the main factors that affect broomrape development. The objective of this study was to optimize small broomrape chemical control in red clover based on growing degree days (GDD). The study was conducted in controlled temperature conditions. Red clover plants were grown in soil artificially infested with small broomrape seeds. Imazamox was applied at 800, 1,000, 1,200, and 1,400 GDD. There was no injury to red clover from any imazamox treatment at any of the application timings. Small broomrape shoot emergence was reduced where imazamox was applied compared to the untreated control. Early imazamox applications reduced small broomrape biomass more than later applications. Control was greatest when imazamox was applied at 20 g ai ha−1 at 1,000 GDD. This application controlled small broomrape for 800 GDD after initial treatment. However, season-long control would require an additional treatment. This model predicts the optimal timing and rate of imazamox application for small broomrape control in red clover.
Functional relationships between giant ragweed (Ambrosia trifida) interference and sweet corn yield and ear traits
Authors: Williams Martin M. , Masiunas John B.
Published: September 2006

Field experiments were conducted to quantify functional relationships between giant ragweed density and sweet corn yield and ear traits. A rectangular hyperbolic model was fit to yield loss measured in terms of marketable ear mass, appropriate for the processing industry, and boxes of 50 marketable ears, relevant to the fresh market industry. The initial slope of the hyperbolic yield loss function (I), which describes the linear portion of yield loss as weed density (weeds per square meter) approaches zero, was 119 for loss of ear mass and 97 for loss of boxes of ears. Furthermore, 10 of 12 ear traits including green ear mass, husked ear mass, ear length, filled ear length, ear width, number of kernels per row, number of rows, kernel depth, kernel mass, and kernel moisture content were significantly affected by giant ragweed interference.
Transcriptome analysis of leafy spurge (Euphorbia esula) crown buds during shifts in well-defined phases of dormancy
Authors: Horvath David P. , Anderson James V. , Soto-Suárez Mauricio , Chao Wun S.
Published: September 2006

Microarray analysis was used to follow changes in gene expression coinciding with seasonal changes in the dormancy status of crown buds of field-grown leafy spurge. Known cold-regulated genes were induced, and numerous gibberellic acid–responsive genes were down-regulated during the transition from paradormancy to endodormancy. Genes involved in photomorphogenesis were induced during endodormancy. Also, ethylene signaling responses were observed during ecodormancy rather than endodormancy. These results provide additional insights into the signals regulating expression of several genes previously associated with transition from paradormancy to growth in root buds.
cAMP-mediated signaling normalizes glucose-stimulated insulin secretion in uncoupling protein-2 overexpressing β-cells
Authors: McQuaid T S , Saleh M C , Joseph J W , Gyulkhandanyan A , Manning-Fox J E , MacLellan J D , Wheeler M B , Chan C B
Published: September 2006

We investigated whether an increase in cAMP could normalize glucose-stimulated insulin secretion (GSIS) in uncoupling protein-2 (UCP2) overexpressing (ucp2-OE) β-cells. Indices of β-cell (β-TC-6f7 cells and rodent islets) function were measured after induction of ucp2, in the presence or absence of cAMP-stimulating agents, analogs, or inhibitors. Islets of ob/ob mice had improved glucose-responsiveness in the presence of forskolin. Rat islets overexpressing ucp2 had significantly lower GSIS than controls. Acutely, the protein kinase A (PKA) and epac pathway stimulant forskolin normalized insulin secretion in ucp2-OE rat islets and β-TC-6f7 β-cells, an effect blocked by specific PKA inhibitors but not mimicked by epac agonists. However, there was no effect of ucp2-OE on cAMP concentrations or PKA activity. In ucp2-OE islets, forskolin inhibited ATP-dependent potassium (KATP) channel currents and 86Rb+ efflux, indicative of KATP block. Likewise, forskolin application increased intracellular Ca2+, which could account for its stimulatory effects on insulin secretion. Chronic exposure to forskolin increased ucp2 mRNA and exaggerated basal secretion but not GSIS. In mice deficient in UCP2, there was no augmentation of either cAMP content or cAMP-dependent insulin secretion. Thus, elevating cellular cAMP can reverse the deficiency in GSIS invoked by ucp2-OE, at least partly through PKA-mediated effects on the KATP channel.
The neuroendocrine system of invertebrates: a developmental and evolutionary perspective
Authors: Hartenstein Volker
Published: September 2006

Neuroendocrine control mechanisms are observed in all animals that possess a nervous system. Recent analyses of neuroendocrine functions in invertebrate model systems reveal a great degree of similarity between phyla as far apart as nematodes, arthropods, and chordates. Developmental studies that emphasize the comparison between different animal groups will help to shed light on questions regarding the evolutionary origin and possible homologies between neuroendocrine systems. This review intends to provide a brief overview of invertebrate neuroendocrine systems and to discuss aspects of their development that appear to be conserved between insects and vertebrates.
Interleukin-6 Increases Insulin-Stimulated Glucose Disposal in Humans and Glucose Uptake and Fatty Acid Oxidation In Vitro via AMP-Activated Protein Kinase
Authors: Carey Andrew L. , Steinberg Gregory R. , Macaulay S. Lance , Thomas Walter G. , Holmes Anna G. , Ramm Georg , Prelovsek Oja , Hohnen-Behrens Cordula , Watt Matthew J. , James David E. , Kemp Bruce E. , Pedersen Bente K. , Febbraio Mark A.
Published: September 2006

Although interleukin-6 (IL-6) has been associated with insulin resistance, little is known regarding the effects of IL-6 on insulin sensitivity in humans in vivo. Here, we show that IL-6 infusion increases glucose disposal without affecting the complete suppression of endogenous glucose production during a hyperinsulinemic-euglycemic clamp in healthy humans. Because skeletal muscle accounts for most of the insulin-stimulated glucose disposal in vivo, we examined the mechanism(s) by which IL-6 may affect muscle metabolism using L6 myotubes. IL-6 treatment increased fatty acid oxidation, basal and insulin-stimulated glucose uptake, and translocation of GLUT4 to the plasma membrane. Furthermore, IL-6 rapidly and markedly increased AMP-activated protein kinase (AMPK). To determine whether the activation of AMPK mediated cellular metabolic events, we conducted experiments using L6 myotubes infected with dominant-negative AMPK α-subunit. The effects described above were abrogated in AMPK dominant-negative–infected cells. Our results demonstrate that acute IL-6 treatment enhances insulin-stimulated glucose disposal in humans in vivo, while the effects of IL-6 on glucose and fatty acid metabolism in vitro appear to be mediated by AMPK.
A Haplotype-Based Analysis of the PTPN22 Locus in Type 1 Diabetes
Authors: Onengut-Gumuscu Suna , Buckner Jane H. , Concannon Patrick
Published: September 2006

A recent addition to the list of widely confirmed type 1 diabetes risk loci is the PTPN22 gene encoding a lymphoid-specific phosphatase (Lyp). However, evidence supporting a role for PTPN22 in type 1 diabetes derives entirely from the study of just one coding single nucleotide polymorphism, 1858C/T. In the current study, the haplotype structure of the PTPN22 region was determined, and individual haplotypes were tested for association with type 1 diabetes in family-based tests. The 1858T risk allele occurred on only a single haplotype that was strongly associated with type 1 diabetes (P = 7.9 × 10−5). After controlling for the effects of this allele, two other haplotypes were observed to be weakly associated with type 1 diabetes (P < 0.05). Sequencing of the coding region of PTPN22 on these haplotypes revealed a novel variant (2250G/C) predicted to result in a nonsynonymous amino acid substitution. Analysis of PTPN22 transcripts from a subject heterozygous for this variant indicated that it interfered with normal mRNA splicing, resulting in a premature termination codon after exon 17. These results support the conclusion that the 1858C/T allele is the major risk variant for type 1 diabetes in the PTPN22 locus, but they suggest that additional infrequent coding variants at PTPN22 may also contribute to type 1 diabetes risk.
Serum Visfatin Increases With Progressive β-Cell Deterioration
Authors: López-Bermejo Abel , Chico-Julià Berta , Fernàndez-Balsells Mercè , Recasens Mònica , Esteve Eduardo , Casamitjana Roser , Ricart Wifredo , Fernández-Real José-Manuel
Published: September 2006

Visfatin has shown to be increased in type 2 diabetes but to be unrelated to insulin sensitivity. We hypothesized that visfatin is associated with insulin secretion in humans. To this aim, a cross-sectional study was conducted in 118 nondiabetic men and 64 (35 men and 29 women) type 2 diabetic patients. Type 1 diabetic patients with long-standing disease (n = 58; 31 men and 27 women) were also studied. In nondiabetic subjects, circulating visfatin (enzyme immunoassay) was independently associated with insulin secretion (acute insulin response to glucose [AIRg] from intravenous glucose tolerance tests) but not with insulin sensitivity (Si) or other metabolic or anthropometric parameters, and AIRg alone explained 8% of visfatin variance (β = −0.29, P = 0.001). Circulating visfatin was increased in type 2 diabetes (mean 18 [95% CI 16–21] vs. 15 ng/ml [13–17] for type 2 diabetic and nondiabetic subjects, respectively; P = 0.017, adjusted for sex, age, and BMI), although this association was largely attenuated after accounting for HbA1c (A1C). Finally, circulating visfatin was found to be increased in patients with long-standing type 1 diabetes, even after adjusting for A1C values (37 ng/ml [34–40]; P < 0.0001, adjusted for sex, age, BMI, and A1C compared with either type 2 diabetic or nondiabetic subjects). In summary, circulating visfatin is increased with progressive β-cell deterioration. The study of the regulation and role of visfatin in diabetes merits further consideration.
Common Single Nucleotide Polymorphisms in TCF7L2 Are Reproducibly Associated With Type 2 Diabetes and Reduce the Insulin Response to Glucose in Nondiabetic Individuals
Authors: Saxena Richa , Gianniny Lauren , Burtt Noël P. , Lyssenko Valeriya , Giuducci Candace , Sjögren Marketa , Florez Jose C. , Almgren Peter , Isomaa Bo , Orho-Melander Marju , Lindblad Ulf , Daly Mark J. , Tuomi Tiinamaija , Hirschhorn Joel N. , Ardlie Kristin G. , Groop Leif C. , Altshuler David
Published: September 2006

Recently, common noncoding variants in the TCF7L2 gene were strongly associated with increased risk of type 2 diabetes in samples from Iceland, Denmark, and the U.S. We genotyped 13 single nucleotide polymorphisms (SNPs) across TCF7L2 in 8,310 individuals in family-based and case-control designs from Scandinavia, Poland, and the U.S. We convincingly confirmed the previous association of TCF7L2 SNPs with the risk of type 2 diabetes (rs7903146T odds ratio 1.40 [95% CI 1.30–1.50], P = 6.74 × 10−20). In nondiabetic individuals, the risk genotypes were associated with a substantial reduction in the insulinogenic index derived from an oral glucose tolerance test (risk allele homozygotes have half the insulin response to glucose of noncarriers, P = 0.003) but not with increased insulin resistance. These results suggest that TCF7L2 variants may act through insulin secretion to increase the risk of type 2 diabetes.
Retinol-Binding Protein 4 in Human Obesity
Authors: Janke Jürgen , Engeli Stefan , Boschmann Michael , Adams Frauke , Böhnke Jana , Luft Friedrich C. , Sharma Arya M. , Jordan Jens
Published: September 2006

Studies in mice suggest that adipocytes serve as glucose sensors and regulate systemic glucose metabolism through release of serum retinol-binding protein 4 (RBP4). This model has not been validated in humans. RBP4 was highly expressed in isolated mature human adipocytes and secreted by differentiating human adipocytes. In contrast to the animal data, RBP4 mRNA was downregulated in subcutaneous adipose tissue of obese women, and circulating RBP4 concentrations were similar in normal weight, overweight, and obese women (n = 74). RBP4 was positively correlated with GLUT4 expression in adipose tissue, independent of any obesity-associated variable. Five percent weight loss slightly decreased adipose RBP4 expression but did not influence circulating RBP4. In another set of experiments, we stratified patients (n = 14) by low or high basal fasting interstitial glucose concentrations, as determined by the microdialysis technique. Venous glucose concentrations were similar throughout oral glucose tolerance testing, and basal RBP4 expression in adipose tissue and serum RBP4 concentrations were similar in the groups with higher and lower interstitial glucose levels. Our findings point to profound differences between rodents and humans in the regulation of adipose or circulating RBP4 and challenge the notion that glucose uptake by adipocytes has a dominant role in the regulation of RBP4.
Dietary Fiber Intake, Dietary Glycemic Load, and the Risk for Gestational Diabetes Mellitus
Authors: Zhang Cuilin , Liu Simin , Solomon Caren G. , Hu Frank B.
Published: September 2006

OBJECTIVE—We aimed to examine whether pregravid dietary fiber consumptions from cereal, fruit, and vegetable sources and dietary glycemic load were related to gestational diabetes mellitus (GDM) risk.

RESEARCH DESIGN AND METHODS—This study was a prospective cohort study among 13,110 eligible women in the Nurses’ Health Study II. GDM was self-reported and validated by medical record review in a subsample.

RESULTS—We documented 758 incident GDM cases during 8 years of follow-up. After adjustment for age, parity, prepregnancy BMI, and other covariates, dietary total fiber and cereal and fruit fiber were strongly associated with GDM risk. Each 10-g/day increment in total fiber intake was associated with 26% (95% CI 9–49) reduction in risk; each 5-g/day increment in cereal or fruit fiber was associated with a 23% (9–36) or 26% (5–42) reduction, respectively. Dietary glycemic load was positively related to GDM risk. Multivariate relative risk for highest versus lowest quintiles was 1.61 (1.02–2.53) (P for trend 0.03). The combination of high–glycemic load and low–cereal fiber diet was associated with 2.15-fold (1.04–4.29) increased risk compared with the reciprocal diet.

CONCLUSIONS—These findings suggested that prepregnancy diet might be associated with women’s GDM risk. In particular, diet with low fiber and high glycemic load was associated with an increased risk. Future clinical and metabolic studies are warranted to confirm these findings.
Low Testosterone and High C-Reactive Protein Concentrations Predict Low Hematocrit in Type 2 Diabetes
Authors: Bhatia Vishal , Chaudhuri Ajay , Tomar Rashmi , Dhindsa Sandeep , Ghanim Husam , Dandona Paresh
Published: September 2006

OBJECTIVE—After the demonstration that one-third of male patients with type 2 diabetes have hypogonadotrophic hypogonadism, we have shown that patients with hypogonadotrophic hypogonadism also have markedly elevated C-reactive protein (CRP) concentrations. We have now hypothesized that type 2 diabetic subjects with hypogonadotrophic hypogonadism may have a lower hematocrit because testosterone stimulates, whereas chronic inflammation suppresses, erythropoiesis.

RESEARCH DESIGN AND METHODS—Seventy patients with type 2 diabetes at a tertiary referral center were included in this study.

RESULTS—The mean hematocrit in patients with hypogonadotrophic hypogonadism (n = 37), defined as calculated free testosterone (cFT) of <6.5 ng/dl, was 40.6 ± 1.1%, whereas that in eugonadal patients (n = 33) was 43.3 ± 0.7% (P = 0.011). The hematocrit was related to cFT concentration (r = 0.46; P < 0.0001); it was inversely related to plasma CRP concentration (r = 0.41; P < 0.0004). Patients with CRP <3 mg/l had a higher hematocrit (42.7 ± 0.7%) than those with CRP >3 mg/l (39.9 ± 1.1%; P < 0.05). The prevalence of normocytic normochromic anemia (hemoglobin <13 g/dl) was 23% in the entire group, whereas it was 37.8% in the men with hypogonadotrophic hypogonadism and 3% in the eugonadal men (P < 0.01). Erythropoietin concentration was elevated or high normal in all 11 patients with anemia in whom it was tested.

CONCLUSIONS—We conclude that hypogonadotrophic hypogonadism in male type 2 diabetic subjects is associated with a lower hematocrit and a frequent occurrence of mild normocytic normochromic anemia with normal or high erythropoietin concentrations. In these patients, hematocrit is also inversely related to CRP concentration. Thus, low testosterone and chronic inflammatory mechanisms may contribute to mild anemia. Such patients may also have a high risk of atherosclerotic cardiovascular events in view of their markedly elevated CRP concentrations.
High Plasma Concentration of Remnant Lipoprotein Cholesterol in Obese Children and Adolescents
Authors: Choi Yong Jun , Jo Young Eun , Kim Yun Kyung , Ahn Sang Mi , Jung Sun Hye , Kim Hae Jin , Chung Yoon-Sok , Lee Kwan Woo , Kim Dae Jung
Published: September 2006

OBJECTIVE—Remnant lipoproteins (RLPs) are the products of the lipolytic degradation of triglyceride-rich lipoproteins produced by the liver and intestine. Recent studies have demonstrated that RLPs are correlated with cardiovascular risk. We assessed the relationship between obesity and RLP and evaluated the factors related to RLP in children and adolescents.

RESEARCH DESIGN AND METHODS—We measured BMI, waist circumference, blood pressure, body fat mass, total abdominal fat, visceral and subcutaneous fat areas, fasting glucose, insulin, total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, and RLP cholesterol in 135 children and adolescents (67 boys and 68 girls). Plasma RLP fractions were isolated using an immunoaffinity gel containing specific anti–apolipoprotein (apo) B-100 and anti–apoA-I antibodies. Based on the BMI percentile, the subjects were divided into two groups: normal (<85th percentile) and overweight (≥85th percentile).

RESULTS—RLP cholesterol was significantly correlated with age, sex, BMI, waist circumference, systolic and diastolic blood pressures, visceral and subcutaneous fat areas, visceral-to-subcutaneous fat area ratio, total cholesterol, triglycerides, HDL cholesterol, apoB, and homeostasis model assessment of insulin resistance (HOMA-IR). According to the multivariate regression analysis, triglycerides (β = 0.928, P < 0.001) were independently correlated with RLP cholesterol. After excluding lipid profiles as an independent variable, the multivariate regression analysis revealed that HOMA-IR (β = 0.231, P = 0.007) and systolic blood pressure (β = 0.169, P = 0.046) were independently associated with RLP cholesterol.

CONCLUSIONS—RLP cholesterol was significantly higher in obese children and adolescents. Triglycerides, systolic blood pressure, and insulin resistance were related to RLP cholesterol.
Displacement washing of pulp with urea solutions
Authors: Potůček F. , Pulcer M.
Published: September 2006

Two basic mechanisms of displacement washing of pulp fibres were investigated. Experiments were carried out in a laboratory washing cell that simulated a single stage of displacement washing. The step-change method has been employed in investigation of alkali lignin profile in outlet stream of washing effluents. The addition of urea to wash water resulted in a decrease of the liquid layer immobilized on the fibre surface. It had a positive effect on the washing efficiency expressed in terms of the void local efficiency.
Citric acid production from raw glycerol by acetate mutants of Yarrowia lipolytica
Authors: Rymowicz W. , Rywińska A. , Żarowska B. , Juszczyk P.
Published: September 2006

Three acetate mutants of the yeast species Yarrowia lipolytica were screened using batch cultivation. The strain Y. lipolytica 1.31 was found to be the most suitable for citric acid production from raw glycerol, a by-product of biodiesel production from rapeseed oil. At the initial concentration of glycerol of 200 g dm−3, the citric acid production of 124.5 g dm−3, yield of 0.62 g g−1, and productivity of 0.88 g dm−3 h−1 were achieved.
Introducing Defects in 3D Photonic Crystals: State of the Art
Authors: Braun P. V. , Rinne S. A. , García‐Santamaría F.
Published: September 2006

3D photonic crystals (PhCs) and photonic bandgap (PBG) materials have attracted considerable scientific and technological interest. In order to provide functionality to PhCs, the introduction of controlled defects is necessary; the importance of defects in PhCs is comparable to that of dopants in semiconductors. Over the past few years, significant advances have been achieved through a diverse set of fabrication techniques. While for some routes to 3D PhCs, such as conventional lithography, the incorporation of defects is relatively straightforward; other methods, for example, self‐assembly of colloidal crystals (CCs) or holography, require new external methods for defect incorporation. In this review, we will cover the state of the art in the design and fabrication of defects within 3D PhCs. The figure displays a fluorescence laser scanning confocal microscopy image of a y‐splitter defect formed through two‐photon polymerization within a CC.
Homologous recombination‐mediated double‐strand break repair in mouse testicular extracts and comparison with different germ cell stages
Authors: Srivastava Niloo , Raman Mercy J.
Published: September 2006

Homologous recombination (HR) is established as a significant contributor to double‐strand break (DSB) repair in mammalian somatic cells; however, its role in mammalian germ cells has not been characterized, although being conservative in nature it is anticipated to be the major pathway in germ cells. The germ cell system has inherent limitations by which intact cell approaches are not feasible. The present study, therefore, investigates HR‐mediated DSB repair in mouse germ cell extracts by using an in vitro plasmid recombination assay based on functional rescue of a neomycin (neo) gene. A significantly high‐fold increase in neo+ (KanR) colonies following incubation of two plasmid substrates (neoΔ1 and neoΔ2) with testicular extracts demonstrated the extracts' ability to catalyze intermolecular recombination. A significant enhancement in recombinants upon linearization of one of the plasmids suggested the existence of an HR‐mediated DSB repair activity. Comparison of the activity at sequential developmental stages, spermatogonia, spermatocytes and spermatids revealed its presence at all the stages; spermatocyte being the most proficient stage. Further, restriction analysis of recombinant plasmids indicated the predominance of gene conversion in enriched spermatocytes (mostly pachytenes), in contrast to gonial and spermatid extracts that showed higher reciprocal exchange. In conclusion, this study demonstrates HR repair activity at all stages of male germ cells, suggesting an important role of HR‐mediated DSB repair during mammalian spermatogenesis. Further, the observed preference of gene conversion over reciprocal exchange at spermatocyte stage correlates with the close association of gene conversion with the meiotic recombination program. Copyright © 2006 John Wiley & Sons, Ltd.
Significance of intraoperative ureteral evaluation at radical cystectomy for urothelial cancer
Authors: Raj Ganesh V. , Tal Raanan , Vickers Andrew , Bochner Bernard H. , Serio Angel , Donat S. Machele , Herr Harry , Olgac Semra , Dalbagni Guido
Published: September 2006

BACKGROUND.

Patients undergoing radical cystectomy (RC) for urothelial cancer are at increased risk for upper tract recurrence and anastomotic recurrence. In an attempt to reduce this recurrence risk, urologists employ intraoperative frozen sections to achieve an uninvolved ureteral margin. The utility of this surgical approach was examined.

METHODS.

A retrospective review identified 1330 bladder cancer patients from 1990 to 2004 with pathologic evaluation of their ureters. Using pathologic findings on permanent section as the reference standard, the accuracy of ureteral frozen sections was examined. Ureteral involvement and margin status were examined as risk factors for upper tract and anastomotic recurrence and overall survival.

RESULTS.

Of 2579 ureteral margins evaluated in 1330 patients, ureteral involvement was noted in 9% of ureters (13% of patients). The sensitivity and specificity of frozen section analyses were approximately 75% and 99%, respectively. The 5‐year probability of anastomotic and upper tract recurrences was low: 2% and 13%, respectively. Evidence of involvement of the ureter or at the ureteral anastomotic margin was associated with higher likelihood of upper tract recurrence but not anastomotic recurrence or overall survival. Furthermore, sequential resection of ureters to reach a negative anastomotic ureteral margin did not eliminate the risk of anastomotic or upper tract recurrence.

CONCLUSIONS.

Patients with involved ureters and/or ureteral anastomotic margins have a higher risk of upper tract recurrence. However, the overall risk of recurrence is low and is not clearly associated with overall survival. The data do not support routine intraoperative frozen sections to assess ureteral involvement. Cancer 2006. © 2006 American Cancer Society.
Hydrocarbon Bond Dissociation Enthalpies: From Substituted Aromatics to Large Polyaromatics
Authors: Van Speybroeck Veronique , Marin Guy B. , Waroquier Michel
Published: September 2006

Hydrocarbon‐bond dissociation enthalpies (BDE) at 298 K are calculated for a set of hydrocarbons. An efficient method for calculating the BDE values is derived on the basis of a comparative study with experimental data. The methods considered are based on density functional theory (DFT) including the B3LYP, MPW1PW91, B3P86, B3PW91, MPW1P86, KMLYP, MPW1K and BMK functionals. The commonly known sequence for radical stability is quantified on the basis of BDE values. The recommended procedure is extrapolated to substituted aromatics and large polyaromatic hydrocarbons (PAHs) to obtain insight into the factors that govern the stability of the radicals. Furthermore it is shown that BDEs are also good reactivity descriptors for subsequent additions involving the formed radicals. Linear correlations, similar to classical Evans–Polanyi–Semenov plots, between the BDE and the reaction barriers for addition reactions with ethene, ethyne, propene, propyne and butadiene are found, as the exothermicity is primarily determined by the stability of the originating reactant radical.
The N3+ Reactivity in Ionized Gases Containing Sulfur, Nitrogen, and Carbon Oxides
Authors: de Petris Giulia , Cartoni Antonella , Angelini Giancarlo , Ursini Ornella , Bottoni Andrea , Calvaresi Matteo
Published: September 2006

The N3+ reactivity with SO2, N2O, CO2, and CO is studied by mass spectrometric techniques under a wide range of pressures from 10−7 to 10−4 Torr. The kinetics, reaction mechanism, and role of vibrationally excited ions are investigated by experimental and theoretical methods. Key distinguishing features of the N3+ reactivity are evidenced by comparison to N+ and N2+ ions, which mainly undergo charge‐exchange reactions. The N+ transfer to SO2 prompts formation of NO+ ions and neutral oxides NO and SO. The N+ transfer to N2O also leads to NO+ ions by a process not allowed by spin conservation rules. In both cases no reaction intermediate is detected, whereas CO2 and CO are captured to form the very stable NCO2+ and NCO+ ions. NCO2+ ions are characterized for the first time as strongly bound triplet ions of NOCO and ONCO connectivity. DFT and CCSD(T) computations have been carried out to investigate the structural and energetic features of the NCO2+ species and their formation process.
Modelling the dynamics of log‐domain circuits
Authors: Ascoli Alon , Curran Paul , Feely Orla
Published: September 2006

Log‐domain filters are an intriguing form of externally linear, internally nonlinear current‐mode circuits, in which a compression stage is first used to convert the input currents to the logarithmic domain, then analogue processing is carried out on the resulting voltages, and finally input–output linearity is restored by mapping the output voltages to current form through an expansion stage. The compressing and expanding operations confer on log‐domain filters a number of desirable features, but they may be responsible for the loss of external linearity. In this paper, sufficient conditions for the external linearity of log‐domain LC‐ladders are established, and the local nature of this external linearity is highlighted. Certain log‐domain LC‐ladders employing floating capacitors may exhibit externally nonlinear behaviour even for zero input and very small initial conditions. We show how transistor parasitic capacitances are central to the emergence of this behaviour, and must be incorporated in the circuit model. Copyright © 2006 John Wiley & Sons, Ltd.
Generation of activin receptor type IIB isoform‐specific hypomorphic alleles
Authors: Lee Young Jae , Hong Kwon‐Ho , Yun Jihye , Oh S. Paul
Published: September 2006

Activin receptor type IIB (Acvr2b) mediates multiple signals for transforming growth factor‐β (TGF‐β) family members, including Activin, Nodal, Bmp7, Gdf1, Gdf3, Myostatin (Gdf8), and Gdf11. Mouse Acvr2b gene generates four transcriptional isoforms (Acvr2b1–4) via alternative splicing of two sequence domains located at the juxtaposition of the transmembrane domain. To investigate whether these splicing domains are essential for signal transduction of the Acvr2b receptor in vivo, we have generated a strain of mutant mice (Acvr2b4/4) which produce only the Acvr2b4 isoform, which lacks both splicing domains. Most homozygous Acvr2b4(neo)/4(neo) mice, in which a neomycin‐resistant cassette was inserted in Intron 4 displayed a mild form of anterior vertebral transformations. However, the penetrance of the vertebral defect was dramatically decreased when the neomycin‐resistant cassette was deleted. These results suggest that the Acvr2b4 isoform is capable of compensating for the deficiency of the other three isoforms. In the absence of its subfamily receptor Acvr2a, however, the development of Acvr2b4/4 mice was arrested at the gastrulation stage, recapitulating the Acvr2a−/−; Acvr2b+/− mutant phenotype. In this study, we demonstrate that this phenomenon is most likely due to the reduction in the expressed Acvr2b4 levels rather than to the functional deficiency of the Acvr2b4 isoform itself. genesis 44:487–494, 2006. © 2006 Wiley‐Liss, Inc.
Group power as a determinant of interdependence and intergroup discrimination
Authors: Rubini Monica , Moscatelli Silvia , Albarello Flavia , Palmonari Augusto
Published: September 2006

This experiment (N = 239) investigated the effects of group power and legitimacy of power differentials on intergroup discrimination, measured through negative outcome allocations and linguistic abstraction. Furthermore, it examined the mechanisms through which group power affects discrimination by testing the mediating role of perceived interdependence and social identification. Three power conditions were created by modifying the standard minimal group paradigm: equal, high and low power conditions. Power was directly proportional (legitimate conditions) or inversely proportional (illegitimate conditions) to group members' performance in a problem‐solving task. Results showed that intergroup discrimination in the high and low power conditions was higher than in the equal power condition on both the allocation and the linguistic measures. Legitimacy moderated the effect of group power on negative outcome allocations, while it had a main effect on the linguistic abstraction. In addition, perceived interdependence turned out to be the main mediator of the effect of power on negative outcome allocations. Copyright © 2006 John Wiley & Sons, Ltd.
Reversal of doxorubicin resistance in breast cancer cells by photochemical internalization
Authors: Lou Pei‐Jen , Lai Ping‐Shan , Shieh Ming‐Jium , MacRobert Alexander J. , Berg Kristian , Bown Stephen G.
Published: September 2006

Multiple drug resistance (MDR) is a problem that seriously reduces the efficacy of many chemotherapy agents. One mechanism for MDR is increased acidification of endocytic vesicles and increased cytosol pH, so weak base chemotherapeutic agents, including doxorubicin, are trapped in endocytic vesicles and exhibit a drug resistant phenotype. Treatments that selectively reverse this accumulation may therefore reverse the MDR phenotype. Photochemical internalization (PCI) is a novel technology developed for site‐specific enhancement of the therapeutic efficacy of macromolecules by selective photochemical rupture of endocytic vesicles and consequent release of endocytosed macromolecules into the cytosol. This study evaluates PCI for release of doxorubicin from endocytic vesicles in MDR cells. Two breast cancer cell lines, MCF‐7 and MCF‐7/ADR (the latter resistant to doxorubicin), were selected. They were found equally sensitive to photochemical treatment with the photosensitiser TPPS2a (disulfonated meso‐tetraphenylporphine) and light. On exposure to doxorubicin alone, the IC50 (drug concentration for 50% reduction in colony formation) was 0.1 μM for MCF‐7 and 1 μM for MCF‐7/ADR. After PCI (photochemical treatment followed by doxorubicin), the IC50 concentration was 0.1 μM for both cell lines. Comparable changes were seen with assay of cell viability using 3‐(4,5‐dimethyltiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT). On fluorescence microscopy in MCF‐7/ADR cells, doxorubicin localised in granules identified as lysosomes. After PCI, doxorubicin was released into the cytosol and entered cell nuclei, as was seen in MCF‐7 cells without PCI. In conclusion, PCI reversed the MDR phenotype of doxorubicin resistant breast cancer cells by endo‐lysosomal release of the drug. The technique is a promising new approach to tackling the problem of MDR. © 2006 Wiley‐Liss, Inc.
Meat consumption and risk of colorectal cancer: A meta‐analysis of prospective studies
Authors: Larsson Susanna C. , Wolk Alicja
Published: September 2006

Accumulating epidemiologic evidence indicates that high consumption of red meat and of processed meat may increase the risk of colorectal cancer. We quantitatively assessed the association between red meat and processed meat consumption and the risk of colorectal cancer in a meta‐analysis of prospective studies published through March 2006. Random‐effects models were used to pool study results and to assess dose‐response relationships. We identified 15 prospective studies on red meat (involving 7,367 cases) and 14 prospective studies on processed meat consumption (7,903 cases). The summary relative risks (RRs) of colorectal cancer for the highest vs. the lowest intake categories were 1.28 (95% confidence interval (CI) = 1.15–1.42) for red meat and 1.20 (95% CI = 1.11–1.31) for processed meat. The estimated summary RRs were 1.28 (95% CI = 1.18–1.39) for an increase of 120 g/day of red meat and 1.09 (95% CI = 1.05–1.13) for an increase of 30 g/day of processed meat. Consumption of red meat and processed meat was positively associated with risk of both colon and rectal cancer, although the association with red meat appeared to be stronger for rectal cancer. In 3 studies that reported results for subsites in the colon, high consumption of processed meat was associated with an increased risk of distal colon cancer but not of proximal colon cancer. The results of this meta‐analysis of prospective studies support the hypothesis that high consumption of red meat and of processed meat is associated with an increased risk of colorectal cancer. © 2006 Wiley‐Liss, Inc.
Human papillomavirus as a risk factor for the increase in incidence of tonsillar cancer
Authors: Hammarstedt Lalle , Lindquist David , Dahlstrand Hanna , Romanitan Mircea , (Dahlgren) Liselotte Onelöv , Joneberg Jeanna , Creson Nomi , Lindholm Johan , Ye Weimin , Dalianis Tina , Munck‐Wikland Eva
Published: September 2006

Smoking and alcohol are well‐known etiological factors in tonsillar cancer. However, as in cervical cancer, human papillomavirus (HPV) is currently found in a sizable proportion of tonsillar cancer. Recent reports from the U.S. and Finland show an increase in the incidence of tonsillar cancer, without a parallel rise in smoking and alcohol consumption. This study investigates whether the incidence of tonsillar cancer has also changed in Sweden and whether a possible explanation of the increase is a higher proportion of HPV‐positive tonsillar cancer. The incidence of tonsillar cancer between 1970 and 2002 in the Stockholm area was obtained from the Swedish Cancer Registry. In parallel, 203 pretreatment paraffin‐embedded tonsillar cancer biopsies taken during 1970–2002 from patients in the Stockholm area were tested for presence of HPV DNA by PCR. The incidence of tonsillar cancer increased 2.8‐fold (2.6 in men and 3.5 in women) from 1970 to 2002. During the same period, a significant increase in the proportion of HPV‐positive tonsillar cancer cases was observed, as it increased 2.9‐fold (p < 0.001). The distribution of HPV‐positive cases was 7/30 (23.3%) in the 1970s, 12/42 (29%) in the 1980s, 48/84 (57%) in the 1990s and 32/47 (68%) during 2000–2002. We have demonstrated a highly significant and parallel increase both in the incidence of tonsillar cancer and the proportion of HPV‐positive tumors. Hence, HPV may play an important role for the increased incidence of tonsillar cancer. This should definitely influence future preventive strategies as well as treatment for this type of cancer. © 2006 Wiley‐Liss, Inc.
Second primary oral and pharyngeal cancers in subjects diagnosed with oral and pharyngeal cancer
Authors: Levi Fabio , Te Van‐Cong , Randimbison Lalao , Maspoli Manuela , La Vecchia Carlo
Published: September 2006

Patients diagnosed with oral and pharyngeal (OP) cancer have a substantial excess risk of second OP cancer, but risk quantification is still uncertain and scanty information is available on the absolute excess risk of second OP cancer. We considered the risk of second OP primary cancer in a population‐based series of 3,092 first primary OP cancers registered between 1974 and 2003 in the Swiss Cantons of Vaud and Neuchâtel (total population of about 786,000 inhabitants). A total of 233 second OP cancers were registered, versus 7.4 expected, corresponding to a SIR of 31.7 (95% confidence interval (CI) 27.7–36.0). The SIR was 68.5 in the first year after diagnosis of the first primary, and declined thereafter, leveling around 20. The SIR was 30.7 when the site of first neoplasm was the oral cavity, 42.5 for the tongue and 28.1 for the oropharynx or hypo‐pharynx. Corresponding values for topographies of second primaries were 28.8, 50.4 and 26.2. The cumulative risk of second OP cancer 15 years after diagnosis of first OP cancer approached 22% in men and 17% in women. The incidence of first primaries increased over 20‐fold between age 30–39 and 70–79, whereas there was no rise with age for second neoplasms. © 2006 Wiley‐Liss, Inc.
Induction of protective immunity to RM‐1 prostate cancer cells with ALVAC‐IL‐2/IL‐12/TNF‐α combination therapy
Authors: Grant Julieann F. , Iwasawa Toshihisa , Sinn Haley W. , Siemens D. Robert , Griffith Thomas S. , Takacs Elizabeth B. , Ratliff Timothy L.
Published: September 2006

Human prostate cancers characteristically express low levels of major histocompatibility complex (MHC) Class I, which makes it challenging to induce protective antitumor responses involving T cells. Here we demonstrate that a whole cell tumor vaccine can induce protective T cell immunity to a low MHC Class I‐expressing mouse prostate cancer cell line, RM‐1. ALVAC recombinant canarypox viruses encoding interleukin‐2, interleukin‐12 and tumor necrosis factor‐α were used to create therapeutic vaccines in 2 different ways. The RM‐1 cells were pre‐infected in vitro with the viruses prior to injection (pre‐infection vaccine) or the RM‐1 cells were injected alone, followed by the viruses (separate injection vaccine). The vaccines were each tested subcutaneously or intradermally. The pre‐infection vaccine resulted in 100% clearance of primary tumors, whereas intradermal delivery of the separate injection vaccine cleared 40–60% of primary tumors. Despite the highly efficient primary tumor clearance by the pre‐infection vaccine, only the separate injection vaccine generated protection upon rechallenge. Tumor‐free survival induced by the separate injection vaccine required natural killer (NK) cells, CD4+, and CD8+ T cells. None of these cells alone were sufficient to induce tumor‐free survival to the primary challenge, demonstrating an important cooperativity between NK cells and T cells. Secondary clearance of tumors also required NK and CD8+ T cells, but not CD4+ T cells. We report for the first time the generation of T cell immunity to the RM‐1 prostate cancer cell line, demonstrating that it is possible to generate protective T cell immunity to a MHC I‐low expressing tumor. © 2006 Wiley‐Liss, Inc.