bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fidelity of Hymenoptera and Diptera pollinators in onion (Allium cepa L.) pollination
Authors: SAEED Shafqat , SAJJAD Asif , KWON Ohseok , KWON Yong Jung 
Published: December 2008

AbstractOnion (Allium cepa L.) is protandrous in nature and requires cross‐pollination to avoid inbreeding. The pollination potential of native bees (Hymenoptera) and true flies (Diptera) was assessed in the perspective of finding the best pollinators for onion cross‐pollination and seed multiplication. The community of pollinators was composed of four bee species and twelve true fly species. Episyrphus balteatus, Eupeodes sp., Musca domestica and Eristalinus aeneus were the most abundant pollinators. The maximum pollinator activity was observed from 12 to 24 days after opening of the flowers. The pollination effectiveness of tested bees (Apis dorsata and Apis florea) was greater than true flies (E. balteatus, Eupeodes sp., M. domestica, E. aeneus and Callihoridae sp.) in terms of Spears values.
Two quediine species (Coleoptera: Staphylinidae: Staphylininae) new to Korea
Authors: CHO Young Bok , AHN Kee‐Jeong 
Published: December 2008

AbstractTwo quediine species (Quedius samuraicus Bernhauer and Schubert, and Velleius elongatus Naomi) were identified for the first time in Korea. Diagnoses and illustrations of the habitus and male genitalia are presented.
Time‐resolved Luminescence and Singlet Oxygen Formation After Illumination of the Hypericin–Low‐density Lipoprotein Complex
Authors: Gbur Peter , Dedic Roman , Chorvat Jr Dusan , Miskovsky Pavol , Hala Jan , Jancura Daniel 
Published: December 2008

AbstractTime‐resolved fluorescence and phosphorescence study of hypericin (Hyp) in complex with low‐density lipoproteins (LDL) as well as the evolution of singlet oxygen formation and annihilation after illumination of Hyp/LDL complexes at room temperature are presented in this work. The observed shortening of the fluorescence lifetime of Hyp at high Hyp/LDL molar ratios (>25:1) proves the self‐quenching of the excited singlet state of monomeric Hyp at these concentration ratios. The very short lifetime (∼0.5 ns) of Hyp fluorescence at very high Hyp/LDL ratios (>150:1) suggests that at high local Hyp concentration inside LDL molecules fast and ultrafast nonradiative decay processes from excited singlet state of Hyp become more important. Contrary to the lifetime of the singlet excited state, the lifetime (its shorter component) of Hyp phosphorescence is not dependent on Hyp/LDL ratio in the studied concentration range. The amount of singlet oxygen produced as well as the integral intensity of Hyp phosphorescence after illumination of Hyp/LDL complexes resemble the dependence of the concentration of molecules of Hyp in monomeric state on Hyp/LDL until a concentration ratio of 60:1. This fact confirms that only monomeric Hyp is able to produce the excited triplet state of Hyp, which in aerobic conditions leads to singlet oxygen production. The value of singlet oxygen lifetime (∼8 μs) after its formation from the excited triplet state of Hyp in LDL proves that molecules of singlet oxygen remain for a certain period of time inside LDL particles and are not immediately released to the aqueous surrounding. That Hyp exists in the complex with LDL in the monodeprotonated state is also demonstrated.
Challenges in Applying Photoemission Electron Microscopy to Biological Systems†
Authors: Peles Dana N. , Simon John D. 
Published: December 2008

AbstractPhotoemission electron microscopy (PEEM) is a unique surface‐sensitive instrument capable of providing real‐time images with high spatial resolution. While similar to the more common electron microscopies, scanning electron microscopy and transmission electron microscopy, the imaging technology relies on the photogeneration of electrons emitted from a sample through light excitation. This imaging technique has found prominence in surface and materials sciences, being well suited for imaging flat surfaces, and changes that occur to that surface as various parameters are changed (e.g. temperature, exposure to reactive gases). Biologically focused PEEM received significant attention in the 1970s, but was not aggressively advanced since that pioneering work. PEEM is capable of providing important insights into biological systems that extend beyond simple imaging. In this article, we identify and establish important issues that affect the acquisition and analysis of biological samples with PEEM. We will briefly review the biological impact and importance of PEEM with respect to our work. The article also concludes with a discussion of some of the current challenges that must be addressed to enable PEEM to achieve its maximum potential with biological samples.
Trajectory Optimization for DDE Models of Supercavitating Underwater Vehicles
Authors: Bottasso Carlo L. , Scorcelletti Francesco , Ruzzene Massimo , Ahn Seong S. 
Published: December 2008

Abstract
In this study we first develop a flight mechanics model for supercavitating vehicles, which is formulated to account for the dependence of the cavity shape from the past history of the system. This mathematical model is governed by a particular class of delay differential equations, featuring time delays on the states of the system. Next, flight trajectories and maneuvering strategies for supercavitating vehicles are obtained by solving an optimal control problem, whose solution, given a cost function and general constraints and bounds on states and controls, yields the control time histories that maneuver the vehicle according to a desired strategy, together with the associated flight path. The optimal control problem is solved using a novel direct multiple shooting approach, which is formulated to properly handle conditions dictated by the delay differential equation formulation governing the dynamic behavior of the vehicle. Specifically, the new formulation enforces the state continuity line conditions in a least-squares sense using local interpolations, which supports local time stepping and drastically reduces the number of optimization unknowns. Examples of maneuvers and resulting trajectories demonstrate the effectiveness of the proposed methodology and the generality of the formulation. The results are also compared with those obtained from a previously developed model governed by ordinary differential equations to highlight the differences and demonstrate the need for the current formulation.
Association of
Bacillus anthracis
Capsule with Lethal Toxin during Experimental Infection
Authors: Ezzell J. W. , Abshire T. G. , Panchal R. , Chabot D. , Bavari S. , Leffel E. K. , Purcell B. , Friedlander A. M. , Ribot W. J. 
Published: December 2008

ABSTRACT

Bacillus anthracis
lethal toxin (LT) was characterized in plasma from infected African Green monkeys, rabbits, and guinea pigs. In all cases, during the terminal phase of infection only the protease-activated 63-kDa form of protective antigen (PA
63
) and the residual 20-kDa fragment (PA
20
) were detected in the plasma. No uncut PA with a molecular mass of 83 kDa was detected in plasma from toxemic animals during the terminal stage of infection. PA
63
was largely associated with lethal factor (LF), forming LT. Characterization of LT by Western blotting, capture enzyme-linked immunosorbent assay, and size exclusion chromatography revealed that the antiphagocytic poly-γ-
d
-glutamic acid (γ-DPGA) capsule released from
B. anthracis
bacilli was associated with LT in animal blood in variable amounts. While the nature of this in vivo association is not understood, we were able to determine that a portion of these LT/γ-DPGA complexes retained LF protease activity. Our findings suggest that the in vivo LT complexes differ from in vitro-produced LT and that including γ-DPGA when examining the effects of LT on specific immune cells in vitro may reveal novel and important roles for γ-DPGA in anthrax pathogenesis.
Leishmania donovani
Ornithine Decarboxylase Is Indispensable for Parasite Survival in the Mammalian Host
Authors: Boitz Jan M. , Yates Phillip A. , Kline Chelsey , Gaur Upasna , Wilson Mary E. , Ullman Buddy , Roberts Sigrid C. 
Published: December 2008

ABSTRACT

Mutations within the polyamine biosynthetic pathway of
Leishmania donovani
, the etiological agent of visceral leishmaniasis, confer polyamine auxotrophy to the insect vector or promastigote form of the parasite. However, whether the infectious or amastigote form of the parasite requires an intact polyamine pathway has remained an open question. To address this issue, conditionally lethal Δ
odc
mutants lacking ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, were created by double targeted gene replacement within a virulent strain of
L. donovani
. ODC-deficient promastigotes and axenic amastigotes were auxotrophic for polyamines and capable of robust growth only when exogenous putrescine was supplied in the culture medium, confirming that polyamine biosynthesis is an essential nutritional pathway for
L. donovani
promastigotes. To assess whether the Δ
odc
lesion also affected the ability of amastigotes to sustain a robust infection, macrophage and mouse infectivity experiments were performed. Parasite loads in murine macrophages infected with each of two independent Δ
odc
knockout lines were decreased ∼80% compared to their wild-type counterpart. Furthermore, α-difluoromethylornithine, a suicide inhibitor of ODC, inhibited growth of wild-type
L. donovani
amastigotes and effectively cured macrophages of parasites, thereby preventing host cell destruction. Strikingly, however, parasitemias of both Δ
odc
null mutants were reduced by 6 and 3 orders of magnitude, respectively, in livers and spleens of BALB/c mice. The compromised infectivity phenotypes of the Δ
odc
knockouts in both macrophages and mice were rescued by episomal complementation of the genetic lesion. These genetic and pharmacological studies strongly implicate ODC as an essential cellular determinant that is necessary for the viability and growth of both
L. donovani
promastigotes and amastigotes and intimate that pharmacological inhibition of ODC is a promising therapeutic paradigm for the treatment of visceral and perhaps other forms of leishmaniasis.
Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica
Authors: Esposito R. M.M. , Spaulding S. A. , McKnight D. M. , Van de Vijver B. , Kopalová K. , Lubinski D. , Hall B. , Whittaker T. 
Published: December 2008

Diatom taxa present in the inland streams and lakes of the McMurdo Dry Valleys and James Ross Island, Antarctica, are presented in this paper. A total of nine taxa are illustrated, with descriptions of four new species ( Luticola austroatlantica sp. nov., Luticola dolia sp. nov., Luticola laeta sp. nov., Muelleria supra sp. nov.). In the perennially ice-covered lakes of the McMurdo Dry Valleys, diatoms are confined to benthic mats within the photic zone. In streams, diatoms are attached to benthic surfaces and within the microbial mat matrix. One species, L. austroatlantica, is found on James Ross Island, of the southern Atlantic archipelago, and the McMurdo Dry Valleys. The McMurdo Dry Valley populations are at the lower range of the size spectrum for the species. Streams flow for 6–10 weeks during the austral summer, when temperatures and solar radiation allow glacial ice to melt. The diatom flora of the region is characterized by species assemblages favored under harsh conditions, with naviculoid taxa as the dominant group and several major diatom groups conspicuously absent.
Levels of Tobacco-Specific Nitrosamines and Polycyclic Aromatic Hydrocarbons in Mainstream Smoke from Different Tobacco Varieties
Authors: Ding Yan S. , Zhang Liqin , Jain Ram B. , Jain Ntasha , Wang Richard Y. , Ashley David L. , Watson Clifford H. 
Published: December 2008

Abstract
It has been estimated that one in every five cancer deaths worldwide are related to tobacco use. According to the IARC, 10 polycyclic aromatic hydrocarbons (PAH) and 8 tobacco-specific nitrosamines (TSNA), as well as at least 45 other compounds or substances found in tobacco smoke, are potential human carcinogens. The levels of these carcinogens in contents of tobacco and smoke emissions vary between different tobacco products. We evaluated mainstream smoke emissions from cigarettes made with different types of tobacco to examine the relation between their deliveries of TSNAs and PAHs and any possible influence from tobacco nitrate content. To investigate the contribution of tobacco content to mainstream cigarette smoke deliveries without confounders such as filter design, filter ventilation, and paper porosity, we used custom-made, research-grade, unfiltered cigarettes that contained bright, burley, oriental, reconstituted, or mixtures of these tobaccos. Our findings confirm results from other researchers that tobacco type can influence the mainstream smoke delivery of nicotine, TSNAs, and PAHs. However, we found that the effect varies among individual compounds. In addition, we observed a statistically significant relationship between nitrate content and mainstream smoke 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK); nitrate level also influenced the mainstream smoke deliveries of the summed total of the 10 PAHs identified by IARC as potential human carcinogens. The influence of nitrate on mainstream smoke NNK and PAH levels were of different magnitude and direction. Our results tend to indicate an inverse relation exists between NNK and PAH deliveries when considering different tobacco blends. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3366–71)
Nicotine Metabolism in Three Ethnic/Racial Groups with Different Risks of Lung Cancer
Authors: Derby Kiersten S. , Cuthrell Kristine , Caberto Christian , Carmella Steven G. , Franke Adrian A. , Hecht Stephen S. , Murphy Sharon E. , Le Marchand Loïc 
Published: December 2008

AbstractPreviously, we documented that smoking-associated lung cancer risk is greater in Hawaiians and lower in Japanese compared with Whites. Nicotine metabolism by cytochrome P450 2A6 (CYP2A6) varies across ethnicity/race and is hypothesized to affect smoking behavior. We investigated whether higher CYP2A6 activity results in the smoker extracting more nicotine (adjusting for cigarettes per day) and being exposed to higher levels of tobacco-specific nitrosamine [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)] and pyrene, a representative polycyclic aromatic hydrocarbon. We conducted a cross-sectional study of 585 smokers among the three main ethnic/racial groups in Hawaii and examined whether differences in CYP2A6 activity correlate with the ethnic/racial differences in lung cancer risk. We assessed CYP2A6 activity by nicotine metabolite ratio (total trans-3-hydroxycotinine/total cotinine) and caffeine metabolite ratio (1,7-dimethyl uric acid/1,7-dimethylxanthine) in 12 h urine. We also measured urinary nicotine equivalents (sum of nicotine, cotinine, and trans-3-hydroxycotinine and their respective glucuronides), a marker of nicotine dose, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronide, markers of NNK exposure, and 1-hydroxypyrene, a marker of pyrene exposure. The nicotine metabolite ratio was higher in Whites than in Japanese and intermediate in Hawaiians (P values &lt; 0.05). Cigarettes per day-adjusted nicotine equivalents were lower in Japanese compared with Hawaiians or Whites (P = 0.005 and P &lt; 0.0001, respectively) and greater in men than women (P &lt; 0.0001). Nicotine equivalents and total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol increased with CYP2A6 activity, indicating that smokers with greater nicotine metabolism smoke more extensively and have a higher internal NNK dose. The particularly low nicotine metabolism of Japanese smokers may contribute to their previously described decreased lung cancer risk. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3526–35)
Correlates of Human Papillomavirus Viral Load with Infection Site in Asymptomatic Men
Authors: Flores Roberto , Beibei Lu , Nielson Carrie , Abrahamsen Martha , Wolf Kyle , Lee Ji-Hyun , Harris Robin B. , Giuliano Anna R. 
Published: December 2008

Abstract
Numerous studies have evaluated human papillomavirus (HPV) DNA load in women, especially HPV-16 viral load, and its role in cervical carcinogenicity. Few studies have examined HPV viral load in men, none among asymptomatic men. The aim of the current study is to quantify HPV-16 viral load in male anogenital specimens and to explore its correlates with anatomic sites. Two-hundred and ninety-four specimens from 42 men who tested positive for HPV-16 at one or more anatomic sites were evaluated. HPV DNA was detected with PGMY 09/11 primer and genotyped with reverse line blot assay followed by HPV-16 viral quantification using type-specific real-time PCR assay (TaqMan). The quantitative PCR assay showed a higher sensitivity in HPV-16 viral DNA detection compared with the reverse line blot assay. Viral load varied significantly by anatomic site (P = 0.019). Penile shaft specimens had significantly higher viral load than any other anatomic site evaluated except for the anal canal. HPV-16 viral load was positively correlated between proximal anatomic sites: perianal and anal canal (P = 0.003), perianal and scrotum (P = 0.011), scrotum and glans/corona (P = 0.045), and scrotum and penile shaft (P = 0.037). In conclusion, the penile shaft seemed to be the preferred site for HPV-16 viral replication. Viral load correlation between proximal sites suggested a possible autoinoculation in male HPV transmission. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3573–6)
Methylation of the TWIST1 Promoter, TWIST1 mRNA Levels, and Immunohistochemical Expression of TWIST1 in Breast Cancer
Authors: Gort Eelke H. , Suijkerbuijk Karijn P.M. , Roothaan Suzan M. , Raman Venu , Vooijs Marc , van der Wall Elsken , van Diest Paul J. 
Published: December 2008

Abstract
TWIST1, an antiapoptotic and prometastatic transcription factor, is overexpressed in many epithelial cancers including breast. Only little is known regarding the regulation of TWIST1 in these cancers. Recently, an increase in the TWIST1 promoter methylation has been shown in breast cancers. To correlate the percentage of TWIST1 promoter methylation to the protein levels, we analyzed simultaneously the methylation status as well as the mRNA and the percentage of cells expressing TWIST1 in normal breast tissue and 76 invasive breast cancers. We found that TWIST1 promoter methylation is significantly more prevalent in malignant compared with healthy breast tissue. Furthermore, the percentage of cells expressing TWIST1 was greater in breast malignancy compared with matched healthy tissue from the same patients. There was no correlation, however, between TWIST1 promoter methylation and TWIST1 protein or RNA expression. This indicates that although TWIST1 CpG methylation is useful as a biomarker in breast cancer diagnosis, there is no direct correlation with TWIST1 expression. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3325–30)
Physical Activity and Postmenopausal Breast Cancer: Effect Modification by Breast Cancer Subtypes and Effective Periods in Life
Authors: Schmidt Martina E. , Steindorf Karen , Mutschelknauss Elke , Slanger Tracy , Kropp Silke , Obi Nadia , Flesch-Janys Dieter , Chang-Claude Jenny 
Published: December 2008

Abstract
Physical activity (PA) has been inversely associated with postmenopausal breast cancer risk. However, it is unclear how and in which life periods PA may be effective to reduce breast cancer risk. Moreover, the evidence is still not judged as ‘convincing’ as there is some heterogeneity among study results. Most studies regarded breast cancer as a single disease, at best separated by menopausal status. Yet, breast cancers are heterogeneous and likely have different etiologies. Therefore, we analyzed the association of PA with different breast cancer subtypes in 3,414 postmenopausal cases and 6,569 controls from a case-control study on breast cancer conducted 2002-2005 in Germany (MARIE study). PA in the age periods 30-49 and 50+ years was assessed, including leisure-time PA (sports, cycling, walking) and non-recreational PA (occupational and household activities). There was a significant protective effect of leisure-time PA for ER+/PR+ carcinomas (adjusted odds ratio = 0.71, 95% confidence interval: 0.60, 0.85; trend P = 0.0001), but no effect for ER-/PR- carcinomas. Moreover, looking at physical activity pattern over time, the effect of PA after menopause on reducing breast cancer risk was more pronounced than the effect of PA before menopause. Overall, effects of PA were independent from adult weight gain, body mass index, and energy intake. These findings suggest that leisure-time PA after menopause may reduce postmenopausal breast cancer risk at least in part via hormonal pathways and not solely by changing body composition. Inactive postmenopausal women should be encouraged to become physically active even later in life. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3402–10)
Genetic Variation inCYP19A1and Risk of Breast Cancer and Fibrocystic Breast Conditions among Women in Shanghai, China
Authors: Chen Chu , Sakoda Lori C. , Doherty Jennifer A. , Loomis Melissa M. , Fish Sherianne , Ray Roberta M. , Lin Ming Gang , Fan Wenhong , Zhao Lue Ping , Gao Dao Li , Stalsberg Helge , Feng Ziding , Thomas David B. 
Published: December 2008

AbstractCYP19A1 encodes for aromatase, which irreversibly converts androgens to estrogens; variation in this gene may affect individual susceptibility to breast cancer and other sex hormone-dependent outcomes. In a case-control study nested within a breast self-examination trial conducted in China, we examined whether CYP19A1 polymorphisms (rs1870049, rs1004982, rs28566535, rs936306, rs11636639, rs767199, rs4775936, rs11575899, rs10046, and rs4646) were associated with risk of breast cancer and fibrocystic breast conditions. Cases were diagnosed with breast cancer (n = 614) or fibrocystic breast conditions (n = 465) during 1989 to 2000. Controls were free of breast disease during the same period (n = 879). Presence of proliferative changes within the extratumoral tissue of women with breast cancer and the lesions of women with fibrocystic conditions only was assessed. None of the polymorphisms were associated with overall risk of breast cancer or fibrocystic breast conditions. Differences in breast cancer risk, however, were observed by proliferation status. The risk of breast cancer with (but not without) proliferative fibrocystic conditions was increased among women homozygous for the minor allele of rs1004982 (C), rs28566535 (C), rs936306 (T), and rs4775936 (C) relative to those homozygous for the major allele [age-adjusted odds ratios (95% confidence intervals), 2.19 (1.24-3.85), 2.20 (1.27-3.82), 1.94 (1.13-3.30), and 1.95 (1.07-3.58), respectively]. Also, haplotypes inferred using all polymorphisms were not associated with overall risk of either outcome, although some block-specific haplotypes were associated with an increased risk of breast cancer with concurrent proliferative fibrocystic conditions. Our findings suggest that CYP19A1 variation may enhance breast cancer development in some women, but further confirmation is warranted. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3457–66)