bluuebunny/crossref_metadata_2025 huggingface dataset:
Giant strain in PbZr0.2Ti0.8O3 nanowires
Authors: Zhou Z. H. , Gao X. S. , Wang John , Fujihara K. , Ramakrishna S. , Nagarajan V.
Published: February 2007

The authors report a giant reversible piezoelectric strain of ∼4.2% achieved with single-crystalline PbZr0.2Ti0.8O3 nanowires of ∼70nm in diameter, which is nearly 300% greater than the nominal values reported for ceramic perovskite single crystals. The giant strain arises from the reversible switching of ferroelastic domains. In the nanowires, there is a competition between surface tension, which forces in-plane polarization, and applied electric field, which stabilizes out-of-plane polarization, through the entire voltage cycle, the result of which is the reversible movement of ferroelastic domains.
Anomalous conductivity and positive magnetoresistance in FeSi–SiO2–Si structures in the vicinity of a resistive transition
Authors: Witanachchi S. , Abou Mourad H. , Srikanth H. , Mukherjee P.
Published: February 2007

Electrical and magnetic transport properties of FeSi–SiO2–Si junctions fabricated by depositing FeSi thin films on silicon substrates with the native oxide layer have been investigated. Near room temperature the carriers tunneled across the interface to the substrate with low resistance. With a decreasing temperature, the junction resistance increased more than three orders of magnitude near 270K, which switched the current path to the film. The transition characteristics depend on the conductivity of the silicon substrate. A positive magnetoresistance that peaked near the transition temperature was observed. Similar behavior was seen for CoSi films while TiSi films did not show a transition in resistance.
X-ray diffraction and continuum measurements in silicon crystals shocked below the elastic limit
Authors: Turneaure Stefan J. , Gupta Y. M.
Published: February 2007

The shock wave response of silicon, compressed along [100] and [111], was examined at both the lattice and continuum scales. Peak stresses were below the Hugoniot elastic limit and ranged between 2.8 and 6.9GPa. X-ray diffraction measurements provided the interplaner spacing changes along the shock loading direction. The continuum response was determined by using laser interferometry to measure the rear surface velocity histories. In contrast to earlier results, both the lattice and continuum results were consistent with the known nonlinear elastic constants of silicon. Additionally, the diffracted intensity in the shocked state was considerably larger than the intensity in the ambient state.
Ultrashort pulse generation in lasers by nonlinear pulse amplification and compression
Authors: Zhao L. M. , Tang D. Y. , Cheng T. H. , Lu C.
Published: February 2007

Generation of ultrashort, transform-limited pulses in a laser resonator by means of nonlinear pulse amplification and compression is observed both numerically and experimentally; this constitutes another type of pulse shaping mechanism in the mode-locked lasers. It is shown that as a result of nonlinear pulse compression, mode-locked pulse with pulse width beyond the gain bandwidth limitation could be directly generated in a laser.
Technique for measuring the rotational velocity of a single cell
Authors: Yasokawa Toshiki , Ishimaru Ichirou , Ishizaki Katsumi , Gesyo Kazuhiro , Kuriyama Shigeki , Masaki Tsutomu , Takegawa Kaoru , Tanaka Naotaka
Published: February 2007

A method for measuring the rotational velocity of a cell is presented. In this method, a parallel pencil beam illuminates the cell and the reflected light intensity distribution from the cell surface is observed using an objective lens. In the Fourier transform plane of the lens, this light intensity distribution is translated by an amount that corresponds to the rotational velocity of the cell. This translational velocity can be converted into the rotational velocity. The authors confirmed that the rotational velocity of a cell could be measured using this method by rotating a cancer cell using light pressure.
Direct dynamics simulations using Hessian-based predictor-corrector integration algorithms
Authors: Lourderaj Upakarasamy , Song Kihyung , Windus Theresa L. , Zhuang Yu , Hase William L.
Published: February 2007

In previous research [J. Chem. Phys. 111, 3800 (1999)] a Hessian-based integration algorithm was derived for performing direct dynamics simulations. In the work presented here, improvements to this algorithm are described. The algorithm has a predictor step based on a local second-order Taylor expansion of the potential in Cartesian coordinates, within a trust radius, and a fifth-order correction to this predicted trajectory. The current algorithm determines the predicted trajectory in Cartesian coordinates, instead of the instantaneous normal mode coordinates used previously, to ensure angular momentum conservation. For the previous algorithm the corrected step was evaluated in rotated Cartesian coordinates. Since the local potential expanded in Cartesian coordinates is not invariant to rotation, the constants of motion are not necessarily conserved during the corrector step. An approximate correction to this shortcoming was made by projecting translation and rotation out of the rotated coordinates. For the current algorithm unrotated Cartesian coordinates are used for the corrected step to assure the constants of motion are conserved. An algorithm is proposed for updating the trust radius to enhance the accuracy and efficiency of the numerical integration. This modified Hessian-based integration algorithm, with its new components, has been implemented into the VENUS/NWChem software package and compared with the velocity-Verlet algorithm for the H2CO→H2+CO, O3+C3H6, and F−+CH3OOH chemical reactions.
Undoped electron-hole bilayers in a GaAs∕AlGaAs double quantum well
Authors: Seamons J. A. , Tibbetts D. R. , Reno J. L. , Lilly M. P.
Published: February 2007

The authors present the fabrication details of completely undoped electron-hole bilayer devices in a GaAs∕AlGaAs double quantum well heterostructure with a 30nm barrier. These devices have independently tunable densities of the two-dimensional electron gas and two-dimensional hole gas. The authors report four-terminal transport measurements of the independently contacted electron and hole layers with balanced densities from 1.2×1011cm−2 down to 4×1010cm−2 at T=300mK. The mobilities can exceed 1×106cm2V−1s−1 for electrons and 4×105cm2V−1s−1 for holes.
In vivo full range complex Fourier domain optical coherence tomography
Authors: Wang Ruikang K.
Published: February 2007

The author presents a system and algorithm to achieve full range complex Fourier domain optical coherence tomography (OCT) capable of imaging biological tissues in vivo. The method utilizes the Hilbert transformation to obtain the analytic functions for spatial interference signals obtained from each single wavelength covered in the broadband OCT light source before performing the Fourier transformation to localize the scatters within a sample. A constant carrier frequency is introduced in the spatial OCT interference signal so that its Hilbert transformation is strictly equal to its quadrature representation. The method is experimentally validated for in vivo imaging.
Age and growth of the scalloped hammerhead shark, Sphyrna lewini, in the north-west Atlantic Ocean and Gulf of Mexico
Authors: Piercy Andrew N. , Carlson John K. , Sulikowski James A. , Burgess George H.
Published: February 2007

The scalloped hammerhead, Sphryna lewini (Griffith & Smith, 1834), is a globally exploited species of shark. In order to gain insight into the life history of this species in the USA waters, age and growth was examined from specimens (n = 307) captured from the north-west Atlantic Ocean and from the Gulf of Mexico. The von Bertalanffy growth model resulted in growth parameters of L∞ = 214.8 cm fork length (FL), k = 0.13 year–1, t0 = –1.62 year for males and L∞ = 233.1 cm FL, k = 0.09 year–1, t0 = –2.22 year for females. The oldest age estimates obtained for this population were 30.5 years for both males and females, which corresponded to FL of 234 cm and 241 cm respectively. Bowker’s test of symmetry and Index of Average Per Cent Error suggests that our ageing method represents a non-biased and precise approach to the age assessment. Marginal increments were significantly different between months (Kruskal–Wallis P = 0.017) with a distinct trend of increasing monthly increment growth beginning in January. When compared to previously published studies, our growth estimates suggest slower growth than populations in the Pacific Ocean but faster growth than previously reported in the Gulf of Mexico.
Hard prey specialists or opportunistic generalists? An examination of the diet of the cownose ray, Rhinoptera bonasus
Authors: Collins A. B. , Heupel M. R. , Hueter R. E. , Motta P. J.
Published: February 2007

Atlantic cownose rays (Rhinoptera bonasus) are benthic, suction feeders whose foraging activities have been implicated in severe damage to commercial shellfish industries. With jaws highly modified for durophagy, it has been assumed that R. bonasus are crushing specialists that feed primarily upon hard molluscan prey. Stomach contents from R. bonasus caught within Florida’s Charlotte Harbor estuary between July 2003 and July 2004 were analysed using the index of relative importance (IRI) to determine most important prey types. Prey items were identified from 38 families and fell into nine distinctive groups. The three most dominant prey groups were crustaceans (%IRI = 55.31), polychaetes (%IRI = 25.20) and bivalves (%IRI = 12.58). Shoalmates had more similar diets than non-shoalmates, suggesting group feeding. Most small or softer-bodied prey consumed were relatively intact, indicating lack of prey processing and capture through suction feeding. All larger, harder-bodied prey showed evidence of crushing (fractured and broken shells). Although R. bonasus has been characterised as a hard prey specialist, these results suggest it may behave as an opportunistic generalist, modifying feeding behaviour to consume readily available prey.
Spatial and temporal variation in the reproductive biology of gummy shark Mustelus antarcticus (Chondrichthyes : Triakidae) harvested off southern Australia
Authors: Walker Terence I.
Published: February 2007

Mustelus antarcticus, endemic to southern Australia, exhibits matrotrophic aplacental viviparity. Differences in synchronous ovarian and parturition cycles, mostly annual west and biennial east of longitude 138°E, are explained by environmental differences. Ovulation and parturition peak during November–December and the gestation period is ~12 months. Largest ovarian follicle diameter ranges from 15 to 28 mm at ovulation, and mean wet mass gain is 10-fold from in utero egg (~10 g) to full-term embryo (~100 g) at ~330 mm total length. The sex ratio of embryos in utero is 1:1, and litter size (1 to 57 embryos) rises curvilinearly with maternal length. Length-at-maternity and length-at-maturity increased with rising fishing mortality and subsequently decreased with falling fishing mortality. These patterns are explained by the hypothesis on the ‘phenomenon of apparent change of size-at-maternity’ (and size-at-maturity) caused by gill-net length-selective fishing mortality, which masks any potential density-dependent responses. Male length-at-maturity estimates from seminal vesicle condition, testis development and spermatogenesis stages are similar, but are less than estimates from clasper calcification. Maximum body mass of females is double that of males and, at any length >700 mm, mean body mass of females exceeds that of males.
BLIMP1 regulates cell growth through repression of p53 transcription
Authors: Yan Junli , Jiang Jianming , Lim Ching Aeng , Wu Qiang , Ng Huck-Hui , Chin Keh-Chuang
Published: February 2007

Tight regulation of p53 is essential for maintaining normal cell growth. Here we report that BLIMP1 acts in an autoregulatory feedback loop that controls p53 activity through repression of
p53
transcription. p53 binds to and positively regulates
BLIMP1
, which encodes for a known B cell transcriptional repressor. Knockdown of BLIMP1 by siRNA results in both apoptosis and growth arrest in human colon cancer cells and cell-cycle arrest in primary human fibroblasts. Interestingly, the levels of both
p53
mRNA and protein are substantially increased after BLIMP1 depletion, which is accompanied by the induction of p53 target genes. Importantly, the apoptosis induced by BLIMP1 depletion in HCT116 cells is largely abrogated in cells lacking p53 or in cells depleted in
p53
by siRNA. We further demonstrate that BLIMP1 binds to the
p53
promoter and represses
p53
transcription, and this provides a mechanistic explanation for the induction of p53 response in cells depleted of BLIMP1. Hence, suppression of
p53
transcription is a crucial function of endogenous BLIMP1 and is essential for normal cell growth.
Transgenic induction of mitochondrial rearrangements for cytoplasmic male sterility in crop plants
Authors: Sandhu Ajay Pal S. , Abdelnoor Ricardo V. , Mackenzie Sally A.
Published: February 2007

Stability of the mitochondrial genome is controlled by nuclear loci. In plants, nuclear genes suppress mitochondrial DNA rearrangements during development. One nuclear gene involved in this process isMsh1.Msh1appears to be involved in the suppression of illegitimate recombination in plant mitochondria. To test the hypothesis thatMsh1disruption leads to the type of mitochondrial DNA rearrangements associated with naturally occurring cytoplasmic male sterility in plants, a transgenic approach for RNAi was used to modulate expression ofMsh1in tobacco and tomato. In both species, these experiments resulted in reproducible mitochondrial DNA rearrangements and a condition of male (pollen) sterility. The male sterility was, in each case, heritable, associated with normal female fertility, and apparently maternal in its inheritance. Segregation of the transgene did not reverse the male sterile phenotype, producing stable, nontransgenic male sterility. The reproducible transgenic induction of mitochondrial rearrangements in plants is unprecedented, providing a means to develop novel cytoplasmic male sterile lines for release as non-GMO or transgenic materials.
Hyperpolarized water as an authentic magnetic resonance imaging contrast agent
Authors: McCarney Evan R. , Armstrong Brandon D. , Lingwood Mark D. , Han Songi
Published: February 2007

Pure water in a highly1H spin-polarized state is proposed as a contrast-agent-free contrast agent to visualize its macroscopic evolution in aqueous media by MRI. Remotely enhanced liquids for image contrast (RELIC) utilizes a1H signal of water that is enhanced outside the sample in continuous-flow mode and immediately delivered to the sample to obtain maximum contrast between entering and bulk fluids. Hyperpolarization suggests an ideal contrast mechanism to highlight the ubiquitous and specific function of water in physiology, biology, and materials because the physiological, chemical, and macroscopic function of water is not altered by the degree of magnetization. We present an approach that is capable of instantaneously enhancing the1H MRI signal by up to 2 orders of magnitude through the Overhauser effect under ambient conditions at 0.35 tesla by using highly spin-polarized unpaired electrons that are covalently immobilized onto a porous, water-saturated gel matrix. The continuous polarization of radical-free flowing water allowed us to distinctively visualize vortices in model reactors and dispersion patterns through porous media. A1H signal enhancement of water by a factor of −10 and −100 provides for an observation time of >4 and 7 s, respectively, upon its injection into fluids with aT1relaxation time of >1.5 s. The implications for chemical engineering or biomedical applications of using hyperpolarized solvents or physiological fluids to visualize mass transport and perfusion with high and authentic MRI contrast originating from water itself, and not from foreign contrast agents, are immediate.
Positron emission tomography with computed tomography imaging of neuroinflammation in experimental autoimmune encephalomyelitis
Authors: Radu Caius G. , Shu Chengyi J. , Shelly Stephanie M. , Phelps Michael E. , Witte Owen N.
Published: February 2007

2-[
18
F]Fluoro-2-deoxy-
d
-glucose positron emission tomography ([
18
F]FDG PET) detection of the up-regulated glycolysis associated with malignant transformation is a noninvasive imaging technique used extensively in cancer diagnosis. Although striking similarities exist in glucose transport and metabolism between tumor cells and activated immune cells, the potential use of [
18
F]FDG PET for the diagnosis and evaluation of autoimmune disorders has not been systematically investigated. Here we ask whether [
18
F]FDG PET in conjunction with computed tomography (CT) could be used to monitor a complex autoimmune disorder such as murine experimental autoimmune encephalomyelitis (EAE) and whether this approach is sensitive enough to evaluate therapeutic interventions. We found that (
i
) coregistration of metabolic (i.e., microPET) and high-resolution anatomical (i.e., CT) images allows serial quantification of glycolysis with [
18
F]FDG in various spinal column segments; (
ii
) [
18
F]FDG PET/CT can detect the increased glycolysis associated with paralysis-causing inflammatory infiltrates in the spinal cord; and (
iii
) the [
18
F]FDG measure of glycolysis in the spinal cord is sensitive to systemic immunosuppressive therapy. These results highlight the potential use of serial [
18
F]FDG PET/CT imaging to monitor neuroinflammation in EAE and suggest that similar approaches could be applied to the diagnosis and evaluation of other autoimmune and inflammatory disorders in animal models and in humans.
Effect of phosphorylation and S–S bond-induced dimerization on DNA binding and transcriptional activation by C/EBPβ
Authors: Kim Jae-woo , Tang Qi-Qun , Li Xi , Lane M. Daniel
Published: February 2007

CCAAT enhancer binding protein β (C/EBPβ) plays an essential role in the cascade that triggers adipocyte differentiation. C/EBPβ activates transcription of C/EBPα and peroxisome proliferator-activated receptor-γ, transcriptional activators of genes that give rise to the adipocyte phenotype. Sequential phosphorylation of C/EBPβ/liver activating protein (LAP) on Thr
188
by MAPK and on Ser
184
or Thr
179
by glycogen synthase kinase β (GSK3β) is required for acquisition of DNA binding activity and transcriptional activation. To investigate how phosphorylation and dimerization of C/EBPβ/LAP alter these activities, wild-type (Wt) and mutant rC/EBPβs were prepared and purified to assess DNA binding and transcription in cell-free systems. rC/EBPβ/LAP, phosphorylated by MAPK and GSK3β
in vitro
, produced a >100-fold increase in DNA binding activity. Mutation of the phosphorylation to Glu increased DNA binding activity. Using a cell-free transcription system with nuclear extract from 3T3-L1 preadipocytes and rC/EBPβ/LAP, only doubly phosphorylated rC/EBPβ/LAP (by MAPK and GSK3β) activated transcription driven by Wt C/EBPα, 422/aP2, and SCD1 promoters. Oxidation-induced dimerization of doubly phosphorylated Wt rC/EBPβ/LAP increased DNA binding, whereas unphosphorylated Wt rC/EBPβ/LAP lacked DNA binding activity. Mutation of the C-terminal Cys
296
adjacent to the leucine zipper and Cys
143
just upstream of the DNA binding domain eliminated phosphorylation-, oxidation-, and dimerization-dependent DNA binding activity, whereas mutation of Cys
201
within the basic DNA binding domain had little effect on DNA binding. These findings indicate that dual phosphorylation of C/EBPβ/LAP caused a conformational change that facilitates S–S bond formation and dimerization, rendering the basic region accessible to the C/EBP regulatory element.
A centriole- and RanGTP-independent spindle assembly pathway in meiosis I of vertebrate oocytes
Authors: Dumont Julien , Petri Sebastian , Pellegrin Franz , Terret Marie-Emilie , Bohnsack Markus T. , Rassinier Pascale , Georget Virginie , Kalab Petr , Gruss Oliver J. , Verlhac Marie-Hélène
Published: February 2007

Spindle formation is essential for stable inheritance of genetic material. Experiments in various systems indicate that Ran GTPase is crucial for meiotic and mitotic spindle assembly. Such an important role for Ran in chromatin-induced spindle assembly was initially demonstrated in Xenopus laevis egg extracts. However, the requirement of RanGTP in living meiotic cells has not been shown. In this study, we used a fluorescence resonance energy transfer probe to measure RanGTP-regulated release of importin β. A RanGTP-regulated gradient was established during meiosis I and was centered on chromosomes throughout mouse meiotic maturation. Manipulating levels of RanGTP in mice and X. laevis oocytes did not inhibit assembly of functional meiosis I spindles. However, meiosis II spindle assembly did not tolerate changes in the level of RanGTP in both species. These findings suggest that a mechanism common to vertebrates promotes meiosis I spindle formation in the absence of chromatin-induced microtubule production and centriole-based microtubule organizing centers.
A network of Rab GTPases controls phagosome maturation and is modulated by Salmonella enterica serovar Typhimurium
Authors: Smith Adam C. , Heo Won Do , Braun Virginie , Jiang Xiuju , Macrae Chloe , Casanova James E. , Scidmore Marci A. , Grinstein Sergio , Meyer Tobias , Brumell John H.
Published: February 2007

Members of the Rab guanosine triphosphatase (GTPase) family are key regulators of membrane traffic. Here we examined the association of 48 Rabs with model phagosomes containing a non-invasive mutant of Salmonella enterica serovar Typhimurium (S. Typhimurium). This mutant traffics to lysosomes and allowed us to determine which Rabs localize to a maturing phagosome. In total, 18 Rabs associated with maturing phagosomes, each with its own kinetics of association. Dominant-negative mutants of Rab23 and 35 inhibited phagosome–lysosome fusion. A large number of Rab GTPases localized to wild-type Salmonella-containing vacuoles (SCVs), which do not fuse with lysosomes. However, some Rabs (8B, 13, 23, 32, and 35) were excluded from wild-type SCVs whereas others (5A, 5B, 5C, 7A, 11A, and 11B) were enriched on this compartment. Our studies demonstrate that a complex network of Rab GTPases controls endocytic progression to lysosomes and that this is modulated by S. Typhimurium to allow its intracellular growth.
Did farming arise from a misapplication of social intelligence?
Authors: Mithen Steven
Published: February 2007

The origins of farming is the defining event of human history—the one turning point that has resulted in modern humans having a quite different type of lifestyle and cognition to all other animals and past types of humans. With the economic basis provided by farming, human individuals and societies have developed types of material culture that greatly augment powers of memory and computation, extending the human mental capacity far beyond that which the brain alone can provide. Archaeologists have long debated and discussed why people began living in settled communities and became dependent on cultivated plants and animals, which soon evolved into domesticated forms. One of the most intriguing explanations was proposed more than 20 years ago not by an archaeologist but by a psychologist: Nicholas Humphrey suggested that farming arose from the ‘misapplication of social intelligence’. I explore this idea in relation to recent discoveries and archaeological interpretations in the Near East, arguing that social intelligence has indeed played a key role in the origin of farming and hence the emergence of the modern world.
College Students' Knowledge, Attitudes, and Behaviors Regarding Organ Donation: An Integrated Review of the Literature1
Authors: Feeley Thomas Hugh
Published: February 2007

The current paper provides an integrated review of research literature on college students' knowledge, attitudes, and intentions regarding organ and tissue donation (OTD). Findings across 27 studies indicate that (a) students reported a lack of information and knowledge on OTD; (b) 23% reported signing an organ card or state organ donation registry; (c) positive attitudes were reported toward donation; (d) surveyed students indicated a willingness to become organ donors; and (e) 36% reported having conversations with family about OTD. Self‐efficacy and normative influence theory are recommended as promising theoretical approaches to studying OTD in college student samples.
Supervisor Trustworthiness and Subordinates' Willingness to Provide Extra‐Role Efforts1
Authors: Lapierre Laurent M.
Published: February 2007

A laboratory experiment was used to determine the separate and joint effects of behaviors denoting supervisor trustworthiness on subordinate willingness to provide the supervisor with extra‐role efforts. Results indicate that a supervisor's demonstration of benevolence toward the subordinate outweighed the supervisor's work‐relevant ability and his or her benevolence toward the subordinate's peers in positively influencing subordinate willingness to provide the supervisor with extra‐role efforts. Also, benevolence toward the subordinate's peers moderated the effect of benevolence toward the subordinate, whereby benevolence toward the subordinate had a reduced positive effect when the supervisor was not benevolent toward the subordinate's peers.
Gender Differences in Recovery After Coronary Artery Bypass Graft Surgery
Authors: Schulz Paula , Zimmerman Lani , Barnason Susan , Nieveen Janet
Published: February 2007

This study examined the effect of gender on symptom evaluation, symptom response, and physical functioning following coronary artery bypass graft surgery. Symptom evaluation and symptom response were measured at baseline and 2, 4, and 6 weeks and 3 months following surgery, and physical functioning was measured at baseline, 6 weeks, and 3 months. The sample included 46 men and 19 women randomly assigned to the routine care group of a larger study examining symptom management intervention influence on recovery outcomes in elderly coronary artery bypass graft patients. No significant differences were found in symptom evaluation, symptom response, or physical functioning by gender over time. Women reported consistently higher symptom evaluation scores for shortness of breath, fatigue, depression, sleep disturbance, swelling, and anxiety and lower mean physical and vitality subscale scores than men at every time point. Gender‐specific symptom management strategies should be developed and tested to address the differences in the reporting of symptoms by men and women.
Predictors of Health Status for Heart Failure Patients
Authors: De Jong Maj Marla J. , Moser Debra K. , Chung Misook L.
Published: February 2007

Health status is poorly understood for patients with heart failure. The purpose of this study was to determine the relative importance of relevant sociodemographic, clinical, health perception, and emotional variables in predicting health status. In this study of 87 patients, health status was conceptualized as health‐related quality of life, physical activity level, and symptom burden. Hierarchical multiple regression was used to determine sociodemographic, clinical health perception, and emotional variables associated with health status. Worse New York Heart Association class, higher anxiety, and higher depression predicted worse health‐related quality of life. Better New York Heart Association class and higher anxiety predicted higher levels of physical activity. Worse New York Heart Association class and higher depression predicted greater symptom burden. Traditional demographic and clinical variables were not associated with health status. Although not routinely assessed, emotional variables had a major impact on health status. Interventions to improve health status should target both physical and emotional well‐being.
Severity of gastritis determines glandular stomach carcinogenesis in Helicobacter pylori‐infected Mongolian gerbils
Authors: Cao Xueyuan , Tsukamoto Tetsuya , Nozaki Koji , Tanaka Harunari , Cao Liyu , Toyoda Takeshi , Takasu Shinji , Ban Hisayo , Kumagai Toshiko , Tatematsu Masae
Published: February 2007

Helicobacter pylori (H. pylori) infection causes chronic gastritis and is also related to gastric carcinoma. The present study focused on severity of H. pylori‐induced gastritis as a determinant of carcinogenesis. Seven‐week‐old male Mongolian gerbils were inoculated with H. pylori at experimental weeks 0, 12, or 18, then given N‐methyl‐N‐nitorosourea (MNU) from weeks 20–40. At week 70, stomachs were then excised for histological examination 70, 58, or 52 weeks after H. pylori inoculation, respectively (Groups A, B, and C for long‐, middle‐, and short‐term). The respective incidences of glandular stomach adenocarcinomas were 65.0% (13/20), 20.0% (2/10), and 23.0% (3/13) (P < 0.05). Higher scores of infiltration of inflammatory cells, hyperplasia, intestinal metaplasia and mucosal bromodeoxyuridine (BrdU) labeling index in antrum and corpus mucosa, were seen in group A than B or C (P < 0.05) and serum anti‐H. pylori IgG titer and gastrin levels were also significantly higher, along with mRNA levels for mucosal interleukin‐1β (IL‐1β), tumor necrosis factor‐α (TNF‐α), cyclooxygenase‐2 (COX‐2), and inducible nitric oxide synthase (iNOS). The results demonstrated the term and severity of H. pylori infection to play important roles in gastric carcinogenesis, with essential involvement of chronic inflammation, especially increased rates of cell proliferation, in H. pylori‐associated carcinogenesis. (Cancer Sci 2007; 98: 478–483)
Intrinsic, inter‐specific competition between egg, egg–larval, and larval parasitoids of plusiine loopers
Authors: YAMAMOTO DAISUKE , HENDERSON RUTH , CORLEY LAURA S. , IWABUCHI KIKUO
Published: February 2007

Abstract 1. Intrinsic, inter‐specific competition between parasitoid wasp species is a key factor in ecological community dynamics and is particularly important for application in biological control. Here three parasitoid wasp species with overlapping host ranges and differing life history strategies were chosen to examine parasitoid–parasitoid interactions: the egg parasitoid Trichogramma pretiosum, the egg–larval, polyembryonic parasitoid wasp Copidosoma floridanum, and the gregarious larval parasitoid Glyptapanteles pallipes, with the plusiine loopers Acanthoplusia agnata and Trichoplusia ni as hosts.

2. Copidosoma floridanum has been shown to be an intrinsically superior competitor against larval parasitoids because of their production and increased investment in a soldier larval caste during development, but little is known of their interactions with egg parasitoid species. Trichogramma pretiosum completely dominated intrinsic competition with C. floridanum regardless of oviposition order or sex of the C. floridanum egg.

3. Competition between C. floridanum and G. pallipes, however, depended on the host stage at which parasitism occurred, the sex of the C. floridanum egg, and parasitoid development time. Copidosoma floridanum outcompeted G. pallipes overall, despite the fact that G. pallipes injects a polyDNA virus into the host.

4. The sex of the C. floridanum egg was a significant factor in its ability to shift caste ratios to produce more soldiers in response to G. pallipes competition.

5. Only developing female C. floridanum responded to competition with G. pallipes by increasing the ratio of soldier to reproductive larvae, and this happened only when multiparasitism occurred in the host’s 1st and 2nd instar.
Chemical mediation and niche partitioning in non‐pollinating fig‐wasp communities
Authors: PROFFIT MAGALI , SCHATZ BERTRAND , BORGES RENÉE M. , HOSSAERT‐MCKEY MARTINE
Published: February 2007

The parasitic chalcidoid wasps associated with the species‐specific and obligatory pollination mutualisms between Ficus spp. and their agaonid wasp pollinators provide a good model to study the functional organization of communities.

However, communities of non‐pollinating fig wasps (NPFWs) remain little characterized, and their functioning and evolutionary dynamics are still poorly understood.

We studied the communities of NPFWs associated with the monoecious F. racemosa and the dioecious F. hispida. Associated with these two fig species are a total of seven wasp species belonging to three genera. These species present contrasts in life history traits and in timing of oviposition. The species studied are thus broadly representative of the communities of NPFWs associated specifically with fig–pollinator mutualisms.

In our study systems, there is temporal segregation of oviposition time among members of NPFW communities.

We tested the role of volatile chemicals in the attraction of NPFWs associated with these two fig species, and tried to determine if chemical mediation can explain the organization of the communities.

We conducted odour choice tests using a Y‐tube olfactometer. All the NPFWs studied were shown to use volatile chemicals produced by the fig to locate their host. Furthermore, the signals used by each species depended on the phenological stage of the fig they exploit.

Results demonstrated that the pattern of oviposition results from the utilization of volatile signals produced by figs that vary in their composition at different stages of fig development. Thus, chemical mediation allows resource partitioning in the NPFW communities associated with fig–pollinator mutualisms, and suggests hypotheses to explain coexistence in other parasite communities.
The soluble forms of CD28, CD86 and CTLA‐4 constitute possible immunological markers in patients with abdominal aortic aneurysm
Authors: Sakthivel P. , Shively V. , Kakoulidou M. , Pearce W. , Lefvert A. K.
Published: February 2007

Objective.  The T cell co‐stimulatory factors CD28 and CTLA‐4 and their ligands CD80 and CD86 occur as receptors on T cells and antigen‐presenting cells and also in soluble forms in the circulation. We determined the levels of soluble co‐stimulatory molecules in patients with abdominal aortic aneurysm (AAA) and normal individuals. We further correlated these soluble co‐stimulatory molecules to other clinical parameters of importance such as age of the patient, presence of hypertension, size of the aneurysm and levels of matrix metalloproteinases‐9 and C‐reactive protein.

Design, setting, subjects.  This case‐control study was designed to quantify the circulating levels of soluble co‐stimulatory molecules by an in‐house enzyme linked immunosorbent assay. A total of 314 subjects participated in the study including 100 patients and 214 normal controls. The statistical analysis was performed by Mann–Whitney test and Spearman's correlation rank test.

Results.  Our results show increased plasma levels of sCD28, sCD86 (P = 0.0001) and decreased plasma levels of sCTLA‐4 (P = 0.0018) in the patients compared with normal individuals. The levels of these factors were not related to the age of the patient, size of aneurysm or levels of C‐reactive protein in plasma. There was, however, a significant inverse relationship between the concentrations of sCTLA‐4 and sCD80 with matrix metalloproteinase‐9.

Conclusions.  We suggest that soluble co‐stimulatory molecules serve as biomarkers for the estimation of immune activation in AAA patients.
Sperm storage and utilization in female Queensland fruit flies (Bactrocera tryoni)
Authors: PEREZ‐STAPLES D. , HARMER A. M. T. , TAYLOR P. W.
Published: February 2007

Abstract Female animals that use sperm from a single mating to fertilize eggs over an extended period require efficient mechanisms for sperm storage and use. There have been few studies of these mechanisms in tephritid flies. Mating, copula duration, sperm storage and sperm usage patterns are assessed in an Australian tephritid, the Queensland fruit fly (Bactrocera tryoni; a.k.a. ‘Q‐fly’). In particular, the present study investigates whether each of these aspects of mating varies in relation to female size or male size, whether sperm storage patterns change over time after mating (1, 5, 10 and 15 days), and the relative roles of the ventral receptacle and the two spermathecae as sperm storage organs. Large females are more likely to mate than are small females, and are also more fecund in the first 5 days after mating. Females are more likely to store some sperm and, among those that store some sperm, store more sperm if their mate is large. Most sperm are stored in the spermathecae (median = 97%), often with high levels of asymmetry between the two spermathecae. Asymmetry of sperm storage is related to number of sperm stored, but not to male or female size. Total number of stored sperm declines over the 15 days after mating, but this decrease in sperm numbers only reflects changes in the spermathecae; numbers of sperm in the ventral receptacle remain unchanged over this period. As a consequence, the proportion of total sperm stored in the spermathecae declines relative to the ventral receptacle. These results are consistent with a system in which small numbers of sperm are maintained in the ventral receptacle for fertilizations, and are replenished by sperm from the spermathecae as required. Sperm distribution and usage patterns in Q‐flies are comparable with recent findings in medflies, Ceratitis capitata, but differ markedly from patterns found in several Anastrepha species.
Copper and iron homeostasis in Arabidopsis: responses to metal deficiencies, interactions and biotechnological applications
Authors: PUIG SERGI , ANDRÉS‐COLÁS NURIA , GARCÍA‐MOLINA ANTONI , PEÑARRUBIA LOLA
Published: February 2007

Plants have developed sophisticated mechanisms to tightly control the acquisition and distribution of copper and iron in response to environmental fluctuations. Recent studies with Arabidopsis thaliana are allowing the characterization of the diverse families and components involved in metal uptake, such as metal‐chelate reductases and plasma membrane transporters. In parallel, emerging data on both intra‐ and intercellular metal distribution, as well as on long‐distance transport, are contributing to the understanding of metal homeostatic networks in plants. Furthermore, gene expression analyses are deciphering coordinated mechanisms of regulation and response to copper and iron limitation. Prioritizing the use of metals in essential versus dispensable processes, and substituting specific metalloproteins by other metal counterparts, are examples of plant strategies to optimize copper and iron utilization. The metabolic links between copper and iron homeostasis are well documented in yeast, algae and mammals. In contrast, interactions between both metals in vascular plants remain controversial, mainly owing to the absence of copper‐dependent iron acquisition. This review describes putative interactions between both metals at different levels in plants. The characterization of plant copper and iron homeostasis should lead to biotechnological applications aimed at the alleviation of iron deficiency and copper contamination and, thus, have a beneficial impact on agricultural and human health problems.
Surface Expression of Transglutaminase 2 by Dendritic Cells and its Potential Role for Uptake and Presentation of Gluten Peptides to T Cells
Authors: Ráki M. , Schjetne K. W. , Stamnaes J. , Molberg Ø. , Jahnsen F. L. , Issekutz T. B. , Bogen B. , Sollid L. M.
Published: February 2007

Celiac disease is a chronic small intestinal inflammation driven by gluten‐reactive T cells of the intestinal mucosa. These T cells are HLA‐DQ2 or ‐DQ8 restricted, and predominantly recognize gluten peptides that are deamidated by the enzyme transglutaminase 2 (TG2). Our recent results strongly suggest that duodenal CD11c+ dendritic cells (DC) are directly involved in T cell activation in the celiac lesion. The aim of this study was to investigate whether surface‐associated TG2 could be involved in receptor‐mediated endocytosis of gluten peptides, a process that may contribute to the preferential recognition of deamidated peptides. We found that both monocyte‐derived DC and local CD11c+ DC in the duodenal mucosa expressed cell surface‐associated TG2. As phenotypic characterization of CD11c+ DC in the celiac lesion suggests that these cells may be derived from circulating monocytes, we used monocyte‐derived DC in functional in vitro studies. Using a functional T cell assay, we obtained evidence that cell surface‐associated TG2 is endocytosed by monocyte‐derived DC. However, we were unable to obtain evidence for a role of surface TG2 in the loading and subsequent generation of deamidated gluten peptides in these cells.
The Time Course of Lymphatic Routes Emanating from the Peritoneal Cavity in Rats
Authors: Shibata S. , Yamaguchi S. , Kaseda M. , Ichihara N. , Hayakawa T. , Asari M.
Published: February 2007

The lymph drainage routes from the abdominal cavity in rats were observed at 3 min, 1, 2 and 4 h after India ink was administered intraperitoneally. Four systems of lymph drainage routes from the peritoneal cavity were observed. Three minutes after injection, the drainage route travelled via the intrathoracic lymph vessels located along the internal thoracic artery and returned to the anterior mediastinal lymph nodes. One hour after injection, the drainage route travelled via the lymph vessel located along the left phrenic nerve in addition to the drainage route observed at 3 min. Two and four hours after injection, in addition to the above‐mentioned routes, the drainage that had travelled via the thoracic duct continued along the right side of the aorta and was also observed in the lateral lymph vessel located on the vertebra. These findings suggest that lymph or cells absorbed into the peritoneal cavity at first travel towards the anterior mediastinal lymph nodes in the thorax via the ventral lymphatic channels, and then gradually course through the dorsal lymphatic channels. These routes may serve as a route for transporting cancer cells and other cells from the peritoneal cavity.
Crossing borders: Nursing practice, teaching and research together into the 21st century
Authors: Walker Kim
Published: February 2007

This paper addresses a research project currently in progress. It is a postmodern ethnographic and (auto)biographical undertaking that simultaneously redraws the methodological and theoretical boundaries of conventional ethnographic work while it engages a ‘praxis’oriented approach to working collaboratively and creatively with nurses from both clinical practice and academia. Only the broadest parameters of this ‘project of possibility’are outlined—to do otherwise would be antithetical to its participatory, processual and provisional character. It is an unprecedented venture between those who think and write about the culture of clinical nursing and those who actually live it on a daily basis.
The lifeworld of relatives of critically ill patients: A phenomenological hermeneutic study
Authors: Walters Allan John
Published: February 2007

This paper describes a phenomenological hermeneutic study of the experiences of relatives of critically ill patients. The study was conducted at a large tertiary referral hospital in Sydney, Australia. The participants were 15 female family members of critically ill patients. Taped conversations between the researcher and participants were conducted and interpreted using a hermeneutic transformative process. Four themes were identified: ‘being‐with’, ‘seeing’, ‘plain talk’and ‘making sense’. The theme ‘plain talk’was concerned with the importance of sensitive and timely communication, and was congruent with previous research findings. The other three themes, however, surfaced new understanding of the relative's experience. ‘Making sense’focused on the participant's understanding of the experience of having a critically ill relative. ‘Being with’was concerned with the desire of the participants to be with their loved one. ‘Seeing’highlighted the importance of actually seeing the patient.
Clinical research priorities in oncology nursing: An Australian perspective
Authors: Chang Esther , Daly John
Published: February 2007

The aims of this research project were to identify areas for research in oncology nursing that have potential for improvement in patient care and to advise about nursing‐research policy and priorities that have relevance to areas of patients’needs. Research participants included 10 Clinical Nurse Consultants (CNC) representing 10 area health authorities in New South Wales, Australia. The Delphi method was used to obtain the most reliable consensus of the specialist nurses, and more than 31 high priorities were identified. Quality of life and symptom management emerged as the top two priority categories in the study. The findings of the study provide direction for clinical nursing research in oncology.
Nurse—doctor relationships in multidisciplinary teams: Ideal or real?
Authors: Warelow Philip J
Published: February 2007

This paper will examine the paradox of power differentials in multidisciplinary teams. The paper begins by offering multidisciplinary teams as an egalitarian enterprise in which all disciplines are included for their particular expertise in relation to patient care. By reviewing ways in which multidisciplinary teams are constructed it will be shown that in nursing discourse these teams are portrayed rhetorically in an idealized rather than realistic way and that there is clearly a power differential between disciplines. The examination highlights the socialized and stereotypical role adopted by the nurse and other disciplines within multidisciplinary teams, so that they fit the social role/rules allotted to them. Investigation of these roles suggest that masculine ideology has prevailed whereby the doctor assumes (without question) the role of team leader. The paper then moves to suggest dissatisfaction with this and that change is underway.
Informed consent: An Israeli bone marrow transplant unit's perspective
Authors: Goldberg Mirah , Musgrave Catherine F.
Published: February 2007

Israeli bone marrow transplant (BMT) patients are drawn from a heterogenous population of Israeli Jews, Israeli Arabs and patients from outside Israel. This presents difficulties in communicating the ethical dilemmas that surround the BMT procedure to the patients and their families. Among these dilemmas is the issue of informed consent. A pilot study was conducted to assess the current informed consent practices in an Israeli BMT Unit. The sample consisted of 13 Hebrew speaking patients. The purpose of the study was to evaluate BMT patients: (i) information seeking behaviour; (ii) preferences for participation in treatment decisions; and (iii) attitudes and behaviours towards the current informed consent document. The study found that patients did not read the informed consent form. Of the nine patients who read it, three considered it superfluous and seven signed it almost immediately after reading it. Surprisingly, the results also showed that, despite the greater degree of risk associated with BMT treatment, the information seeking behaviour scores of BMT patients were similar to those of cancer patients receiving oncology treatment on an ambulatory basis.
Issues related to adolescent pregnancy and child‐rearing: A literature review
Authors: Leslie Kathryn
Published: February 2007

Child‐rearing among very young adolescents (10–14 years) in America has increased 10% between 1981 and 1991. Australian statistics indicate a similar increase. What are the consequences? The cost of adolescent child‐bearing can be felt across three generations. The parents of the adolescent, the child of the adolescent and the adolescent pay heavily emotionally, socio‐economically, physically and developmentally. More positive outcomes can be achieved if an ecological approach is taken by service providers, or if teenagers are exposed to positive parenting techniques such as breast‐feeding. Despite the type of service provided, the teenager must feel comfortable and welcome if they are to take full advantage of it. The South Australian Government has opened to door to more appropriate services with the development of the youth health policy; now the challenge is to make a difference.