bluuebunny/crossref_metadata_2025 huggingface dataset:
The associated factors to endometrial cavity fluid and the relevant impact on the IVF-ET outcome
Authors: He Rong-Huan , Gao Hui-Juan , Li Ya-Qiong , Zhu Xiao-Ming
Published: May 2010

Background

Endometrial cavity fluid (ECF) is a fluid accumulation within the endometrial cavity. The significance of ECF remains unclear during the program of in vitro fertilization-embryo transfer (IVF-ET). The aim of the present study was to investigate the associated factors to ECF, visualized through ultrasound at the day of oocyte retrieval, and the relevant impact on the outcome of IVF-ET.

Methods

From the clinical data of 1557 infertility patients for IVF-ET program, 46 ECF patients were retrospectively selected as the ECF group; and another 134 patients with a bilateral salpingectomy and without ECF, selected as the control group. The demographics and the outcome of IVF-ET were compared between the two groups.

Results

The incidence of ECF was 2.95% (46/1557). Over half (28/46, 60.87%) of ECF patients had tubal infertility. Only 12 Of 46 ECF patients (26.09%) had visible hydrosalpinx on ultrasonography before ovarian stimulation. The cycle cancellation rate (4/46, 8.69%) of ECF group was not significantly higher than that of the control group (6/134, 4.48%; P > 0.05). Reasons for cycle cancellation in both groups were all the high risk of ovarian hyperstimulation syndrome (OHSS). No significant difference was found in clinical pregnancy rate between the patients with their ECF <3.5 mm in the anterior-posterior diameter (APD) and the control group (35.48% versus 30.47%; P > 0.05). No clinical pregnancy was found among those patients with their ECF equal or higher 3.5 mm in APD.

Conclusions

It was tubal infertility, not hydrosalpinx, which was related to the development of ECF. Excessive ECF (equal or higher 3.5 mm in APD) at the day of oocyte retrieval would have a negative impact on the outcome of IVF-ET.
Rapid effects of progesterone on ciliary beat frequency in the mouse fallopian tube
Authors: Bylander Anna , Nutu Magdalena , Wellander Rikard , Goksör Mattias , Billig Håkan , Larsson DG Joakim
Published: May 2010

Background

The physiological regulation of ciliary beat frequency (CBF) within the fallopian tube is important for controlling the transport of gametes and the fertilized ovum. Progesterone influences gamete transport in the fallopian tube of several mammalian species. In fallopian tubes isolated from cows, treatment with 20 micromolar progesterone caused a rapid reduction of the tubal CBF. The aims of this study were to establish methodology for studying fallopian tube CBF in the mouse, as it is an important model species, and to investigate if progesterone rapidly affects the CBF of mice at nM concentrations.

Methods

A method to assess tubal CBF of mice was developed. Fallopian tubes were dissected and the tissue was cut in small pieces. Tissue samples with moving cilia were located under an inverted bright field microscope and held still against the bottom of a petri dish by a motorized needle system. Images were acquired over 90 minutes at 35 degrees C with a high-speed camera and used for assessing changes in the CBF in response to the addition of hormone.

Results

The baseline CBF of the mouse fallopian tube was 23.3 +/- 3.8 Hz. The CBF was stable over at least 90 minutes allowing establishment of a baseline frequency, addition of hormone and subsequent recordings. Progesterone at concentrations of 20 micromolar and 100 nM significantly reduced the CBF by 10% and 15% respectively after 30 minutes compared with controls.

Conclusions

The present study demonstrates that the mouse, despite its small size, is a useful model for studying the fallopian tube CBF ex vivo. The rapid reduction in CBF by 100 nM progesterone suggests that gamete transport in the fallopian tube could be mediated by progesterone via a non-genomic receptor mechanism.
Testing bias in clinical databases: methodological considerations
Authors: Velthove Karin J , Leufkens Hubert GM , Souverein Patrick C , Schweizer René C , van Solinge Wouter W
Published: May 2010

Background

Laboratory testing in clinical practice is never a random process. In this study we evaluated testing bias for neutrophil counts in clinical practice by using results from requested and non-requested hematological blood tests.

Methods

This study was conducted using data from the Utrecht Patient Oriented Database. This clinical database is unique, as it contains physician requested data, but also data that are not requested by the physician, but measured as result of requesting other hematological parameters. We identified adult patients, hospitalized in 2005 with at least two blood tests during admission, where requests for general blood profiles and specifically for neutrophil counts were contrasted in scenario analyses. Possible effect modifiers were diagnosis and glucocorticoid use.

Results

A total of 567 patients with requested neutrophil counts and 1,439 patients with non-requested neutrophil counts were analyzed. The absolute neutrophil count at admission differed with a mean of 7.4 × 109/l for requested counts and 8.3 × 109/l for non-requested counts (p-value < 0.001). This difference could be explained for 83.2% by the occurrence of cardiovascular disease as underlying disease and for 4.5% by glucocorticoid use.

Conclusion

Requests for neutrophil counts in clinical databases are associated with underlying disease and with cardiovascular disease in particular. The results from our study show the importance of evaluating testing bias in epidemiological studies obtaining data from clinical databases.
Intensity modulated radiotherapy with concurrent chemotherapy for larynx preservation of advanced resectable hypopharyngeal cancer
Authors: Huang Wen-Yen , Jen Yee-Min , Chen Chang-Ming , Su Yu-Fu , Lin Chun-Shu , Lin Yaoh-Shiang , Chang Ying-Nan , Chao Hsing-Lung , Lin Kuen-Tze , Chang Li-Ping
Published: May 2010

Background

To analyze the rate of larynx preservation in patients of locally advanced hypopharyngeal cancer treated with intensity modulated radiotherapy (IMRT) plus concurrent chemotherapy, and compare the results with patients treated with primary surgery.

Methods

Between January 2003 and November 2007, 14 patients were treated with primary surgery and 33 patients were treated with concurrent chemoradiotherapy (CCRT) using IMRT technique. Survival rate, larynx preservation rate were calculated with the Kaplan-Meier method. Multivariate analysis was conducted for significant prognostic factors with Cox-regression method.

Results

The median follow-up was 19.4 months for all patients, and 25.8 months for those alive. The 5-year overall survival rate was 33% and 44% for primary surgery and definitive CCRT, respectively (p = 0.788). The 5-year functional larynx-preservation survival after IMRT was 40%. Acute toxicities were common, but usually tolerable. The rates of treatment-related mucositis (≥ grade 2) and pharyngitis (≥ grade 3) were higher in the CCRT group. For multivariate analysis, treatment response and cricoid cartilage invasion strongly correlated with survival.

Conclusions

IMRT plus concurrent chemotherapy may preserve the larynx without compromising survival. Further studies on new effective therapeutic agents are essential.
Sequence embedding for fast construction of guide trees for multiple sequence alignment
Authors: Blackshields Gordon , Sievers Fabian , Shi Weifeng , Wilm Andreas , Higgins Desmond G
Published: May 2010

Background

The most widely used multiple sequence alignment methods require sequences to be clustered as an initial step. Most sequence clustering methods require a full distance matrix to be computed between all pairs of sequences. This requires memory and time proportional to N
2 for N sequences. When N grows larger than 10,000 or so, this becomes increasingly prohibitive and can form a significant barrier to carrying out very large multiple alignments.

Results

In this paper, we have tested variations on a class of embedding methods that have been designed for clustering large numbers of complex objects where the individual distance calculations are expensive. These methods involve embedding the sequences in a space where the similarities within a set of sequences can be closely approximated without having to compute all pair-wise distances.

Conclusions

We show how this approach greatly reduces computation time and memory requirements for clustering large numbers of sequences and demonstrate the quality of the clusterings by benchmarking them as guide trees for multiple alignment. Source code is available for download from http://www.clustal.org/mbed.tgz.
Up-regulation of fas reverses cisplatin resistance of human small cell lung cancer cells
Authors: Wu Wei , Wang Hai-dong , Guo Wei , Yang Kang , Zhao Yun-ping , Jiang Yao-guang , He Ping
Published: May 2010

Background/Aim

Fas/FasL system is a major regulator of apoptosis. The mechanisms by which Fas mediates cisplatin resistance remain unclear. The aim of this study is to explore the effect of Fas over-expression on cisplatin resistance of small cell lung cancer cells and its possible mechanisms.

Materials and methods

Fas was over-expressed in H446/CDDP cells by infection with the adenoviruses containing Fas. Sensitivity of Fas-overexpressed H446/CDDP cells to cisplatin was evaluated using MTT assay. Expressions of Fas, GST-π and ERCC1 were detected by RT-PCR and Western blot analysis. Apoptosis rate was examined by FACS.

Results

Over-expression of Fas in H446/CDDP cells significantly decreased the expressions of GST-π and ERCC1 at mRNA and protein levels, and increased the cell apoptosis. Furthermore, up-regulation of Fas significantly decreased the tolerance of H446/CDDP cells to cisplatin.

Conclusion

Over-expression of Fas reverses drug resistance of H446/CDDP cells, possibly due to the increased cell sensitivity to apoptosis and the decreased expressions of GST-π and ERCC1.
Outcome predictors and quality of life of severe burn patients admitted to intensive care unit
Authors: Pavoni Vittorio , Gianesello Lara , Paparella Laura , Buoninsegni Laura Tadini , Barboni Elisabetta
Published: May 2010

Background

Despite significant medical advances and improvement in overall mortality rate following burn injury, the treatment of patients with extensive burns remains a major challenge for intensivists. We present a study aimed to evaluate the short- and the long-term outcomes of severe burn patients (total body surface area, TBSA > 40%) treated in a polyvalent intensive care unit (ICU) and to assess the quality of life of survivors, one year after the injury using the EuroQol-5D (EQ-5D) questionnaire.

Methods

A prospective-observational study was performed in an ICU of a University-affiliated hospital. Logistic regression analysis was used to identify the factors predicting in-hospital mortality. The EQ-5D questionnaire was used to asses participant's long term self-reported general health.

Results

During a period of five years, 50 patients participated in the study. Their mean age was 53.8 ± 19.8; they had a mean of %TBSA burned of 54.5 ± 18.1. 44% and 10% of patients died in the ICU and in the ward after ICU discharge, respectively. Baux index, SAPS II and SOFA on admission to the ICU, infectious and respiratory complications, and time of first burn wound excision were found to have a significant predictive value for hospital mortality. The level of health of all survivors was worse than before the injury. Problems in the five dimensions studied were present as follows: mobility (moderate 68.5%; extreme 0%), self-care (moderate 21%; extreme 36.9%), usual activities (moderate 68.5%; extreme 21%), pain/discomfort (moderate 68.5%; extreme 10.5%), anxiety/depression (moderate 36.9%; extreme 42.1%).

Conclusions

In severe burn patients, Baux index, severity of illness on admission to the ICU, complications, and time of first burn wound excision were the major contributors to hospital mortality. Quality of life was influenced by consequences of injury both in psychological and physical health.
Plasma and synovial fluid microRNAs as potential biomarkers of rheumatoid arthritis and osteoarthritis
Authors: Murata Koichi , Yoshitomi Hiroyuki , Tanida Shimei , Ishikawa Masahiro , Nishitani Kohei , Ito Hiromu , Nakamura Takashi
Published: May 2010

Introduction

MicroRNAs (miRNAs), endogenous small noncoding RNAs regulating the activities of target mRNAs and cellular processes, are present in human plasma in a stable form. In this study, we investigated whether miRNAs are also stably present in synovial fluids and whether plasma and synovial fluid miRNAs could be biomarkers of rheumatoid arthritis (RA) and osteoarthritis (OA).

Methods

We measured concentrations of miR-16, miR-132, miR-146a, miR-155 and miR-223 in synovial fluid from patients with RA and OA, and those in plasma from RA, OA and healthy controls (HCs) by quantitative reverse transcription-polymerase chain reaction. Furthermore, miRNAs in the conditioned medium of synovial tissues, monolayer fibroblast-like synoviocytes, and mononuclear cells were examined. Correlations between miRNAs and biomarkers or disease activities of RA were statistically examined.

Results

Synovial fluid miRNAs were present and as stable as plasma miRNAs for storage at -20°C and freeze-thawing from -20°C to 4°C. In RA and OA, synovial fluid concentrations of miR-16, miR-132, miR-146a, and miR-223 were significantly lower than their plasma concentrations, and there were no correlation between plasma and synovial fluid miRNAs. Interestingly, synovial tissues, fibroblast-like synoviocytes, and mononuclear cells secreted miRNAs in distinct patterns. The expression patterns of miRNAs in synovial fluid of OA were similar to miRNAs secreted by synovial tissues. Synovial fluid miRNAs of RA were likely to originate from synovial tissues and infiltrating cells. Plasma miR-132 of HC was significantly higher than that of RA or OA with high diagnosability. Synovial fluid concentrations of miR-16, miR-146a miR-155 and miR-223 of RA were significantly higher than those of OA. Plasma miRNAs or ratio of synovial fluid miRNAs to plasma miRNAs, including miR-16 and miR-146a, significantly correlated with tender joint counts and 28-joint Disease Activity Score.

Conclusions

Plasma miRNAs had distinct patterns from synovial fluid miRNAs, which appeared to originate from synovial tissue. Plasma miR-132 well differentiated HCs from patients with RA or OA, while synovial fluid miRNAs differentiated RA and OA. Furthermore, plasma miRNAs correlated with the disease activities of RA. Thus, synovial fluid and plasma miRNAs have potential as diagnostic biomarkers for RA and OA and as a tool for the analysis of their pathogenesis.
Phylogenetic assessment of alignments reveals neglected tree signal in gaps
Authors: Dessimoz Christophe , Gil Manuel
Published: May 2010

Background

The alignment of biological sequences is of chief importance to most evolutionary and comparative genomics studies, yet the two main approaches used to assess alignment accuracy have flaws: reference alignments are derived from the biased sample of proteins with known structure, and simulated data lack realism.

Results

Here, we introduce tree-based tests of alignment accuracy, which not only use large and representative samples of real biological data, but also enable the evaluation of the effect of gap placement on phylogenetic inference. We show that (i) the current belief that consistency-based alignments outperform scoring matrix-based alignments is misguided; (ii) gaps carry substantial phylogenetic signal, but are poorly exploited by most alignment and tree building programs; (iii) even so, excluding gaps and variable regions is detrimental; (iv) disagreement among alignment programs says little about the accuracy of resulting trees.

Conclusions

This study provides the broad community relying on sequence alignment with important practical recommendations, sets superior standards for assessing alignment accuracy, and paves the way for the development of phylogenetic inference methods of significantly higher resolution.
Use of Locum Tenens Physicians in Oncology Practice
Authors: Gesme Dean H. , Towle Elaine L. , Wiseman Marian
Published: May 2010

Who would step in to care for your patients if you had to be away from work for several weeks? Calling in a locum tenens oncologist may be a good solution.
Description of Current Practices of Empiric Chemotherapy Dose Adjustment in Obese Adult Patients
Authors: Thompson Lisa A. , Lawson Amber P. , Sutphin Stephanie D. , Steinke Douglas , Adams Val R.
Published: May 2010

Medical literature is not clear on the best method to empirically dose chemotherapy in obese adult patients. This study sought to characterize current practices and identify factors affecting such decisions.
Challenges to National Cancer Institute–Supported Cooperative Group Clinical Trial Participation: An ASCO Survey of Cooperative Group Sites
Authors: Baer Allison R. , Kelly Chelsey A. , Bruinooge Suanna S. , Runowicz Carolyn D. , Blayney Douglas W.
Published: May 2010

Anecdotal information regarding clinical research sites limiting participation in NCI-funded cooperative group studies prompted ASCO to collect data on and investigate the reasons behind this trend.
Daily Life As an Australian Medical Oncologist
Authors: Adams Diana , Marx Gavin
Published: May 2010

Several models of practice exist in Australia, presenting benefits and challenges to the physicians involved and the communities for which they care.
Human Mesenchymal Stem Cells Modulate Cellular Immune Response to Islet Antigen Glutamic Acid Decarboxylase in Type 1 Diabetes
Authors: Zanone Maria M. , Favaro Enrica , Miceli Ilaria , Grassi Giorgio , Camussi Elisa , Caorsi Cristiana , Amoroso Antonio , Giovarelli Mirella , Perin Paolo Cavallo , Camussi Giovanni
Published: May 2010

Context: Mesenchymal stem cells (MSCs) exert an immunosuppressive effect on the immune system. However, studies on the immunomodulatory potential of MSCs in type 1 diabetes are lacking.

Objective: We aimed to evaluate whether human MSCs may inhibit in vitro pancreatic islet antigen-specific T cell activation in type 1 diabetes.

Design: Human MSCs were isolated and characterized. Peripheral blood mononuclear cells (PBMCs) were obtained from nine type 1 diabetic patients at disease onset and 13 healthy control subjects. IFN-γ, IL-10, and IL-4 enzyme-linked immunospot responses of lymphocytes incubated with glutamic acid decarboxylase 65 (GAD65) were investigated in PBMC cultures and PBMC/MSC cocultures. Levels of prostaglandin E2 (PGE2), IFN-γ, IL-4, and IL-10 in supernatants were measured by ELISA. PGE2 inhibition experiments with NS-398 and indomethacin were also performed.

Results: Five diabetic patients were identified with a positive PBMC IFN-γ response to GAD65 and negative IL-10 and IL-4 response. PBMC/MSC cocultures resulted in a significant decrease in the number of spots and in detection of IL-4-secreting cells. PGE2 inhibitors abrogated the immune-suppressive effect, indicating an involvement of PGE2 production, and the constitutive production of PGE2 by MSCs was enhanced in PBMC/MSC coculture. Moreover, in GAD-responder patients, GAD-stimulated PBMC/MSC cocultures significantly decreased secretion of IFN-γ and IL-10 and increased secretion of IL-4.

Conclusions: These results provide evidence that human MSCs abrogate in vitro a proinflammatory T helper type 1 response to an islet antigenic stimulus in type 1 diabetes. MSCs induce IL-4-producing cells, suggesting a possible switch to an antiinflammatory T helper type 2 signaling of T cells.
Reduced Oxygenation in Human Obese Adipose Tissue Is Associated with Impaired Insulin Suppression of Lipolysis
Authors: Pasarica Magdalena , Rood Jennifer , Ravussin Eric , Schwarz Jean-Marc , Smith Steven R. , Redman Leanne M.
Published: May 2010

Context: Adipose tissue in obese individuals is characterized by reduced capillary density and reduced oxygenation.

Objective: Our objective was to test whether hypoxia is associated with reduced antilipolytic effect of insulin.

Participants, Design, and Setting: Twenty-one lean and obese individuals participated in this cross-sectional study at a university-based clinical research center.

Intervention: In all subjects, in situ adipose tissue (AT) oxygenation [AT oxygen partial pressure (ATpO2)] was measured with a Clark electrode, insulin sensitivity as well as basal and insulin-suppressed lipolysis (continuous infusion of (2H5)glycerol) were measured during a euglycemic-hyperinsulinemic clamp, and abdominal sc AT biopsies were collected to assess fat cell size (Coulter counting of osmium-fixed cells), capillary density (by staining of histological sections), and gene expression (by quantitative RT-PCR).

Main Outcome Measure: In situ ATpO2 was evaluated.

Results: The ability of insulin to suppress lipolysis (percent) was positively correlated with insulin sensitivity (r = 0.43; P < 0.05), ATpO2 (r = 0.44; P < 0.05), vascular endothelial growth factor mRNA (r = 0.73; P < 0.01), and capillary density (r = 0.75; P < 0.01).

Conclusion: These results indicate that low capillary density and ATpO2 in AT are potentially upstream causes of AT dysfunction.
Effect of slow desiccation and freezing on gene transcription and stress survival of an Antarctic nematode
Authors: Adhikari Bishwo N. , Wall Diana H. , Adams Byron J.
Published: May 2010

Nematodes are the dominant soil animals of the Antarctic Dry Valleys and are capable of surviving desiccation and freezing in an anhydrobiotic state. Genes induced by desiccation stress have been successfully enumerated in nematodes; however, little is known about gene regulation by Antarctic nematodes that can survive multiple types and incidences of environmental stress. In order to reveal the molecular response of anhydrobiotic survival, we investigated the genetic response of an Antarctic nematode, Plectus murrayi, which can survive desiccation and freezing. Using molecular approaches, we provide insight into the regulation of desiccation-induced transcripts during different stages of stress survival under conditions characteristic of the Antarctic Dry Valley environment. Our study revealed that exposure to slow desiccation and freezing plays an important role in the transcription of stress, metabolism and signal transduction-related genes and improves desiccation and freezing survival compared with nematodes exposed to fast desiccation and freezing. Temporal analyses of gene expression showed that pre-exposure to mild stress promotes survival of harsher stress. Our results further show that exposure to slow dehydration not only improves extreme desiccation survival but also promotes enhanced cold tolerance. We also provide evidence that slow dehydration can enhance freeze tolerance in an Antarctic nematode. Expression profiling of P. murrayi transcripts is an important step in understanding the genome-level response of this nematode to different environmental stressors.
Target tracking during venom ‘spitting’ by cobras
Authors: Westhoff Guido , Boetig Melissa , Bleckmann Horst , Young Bruce A.
Published: May 2010

Spitting cobras, which defend themselves by streaming venom towards the face and/or eyes of a predator, must be highly accurate because the venom they spit is only an effective deterrent if it lands on the predator's cornea. Several factors make this level of accuracy difficult to achieve; the target is moving, is frequently >1 m away from the snake and the venom stream is released in approximately 50 ms. In the present study we show that spitting cobras can accurately track the movements of a potentially threatening vertebrate, and by anticipating its subsequent (short-term) movements direct their venom to maximize the likelihood of striking the target's eye. Unlike other animals that project material, in spitting cobras the discharge orifice (the fang) is relatively fixed so directing the venom stream requires rapid movements of the entire head. The cobra's ability to track and anticipate the target's movement, and to perform rapid cephalic oscillations that coordinate with the target's movements suggest a level of neural processing that has not been attributed to snakes, or other reptiles, previously.
Evidence that water exudes when holothurian connective tissue stiffens
Authors: Tamori Masaki , Takemae Chigusa , Motokawa Tatsuo
Published: May 2010

The dermis of the body wall of sea cucumbers is composed mainly of extracellular materials such as collagens, proteoglycans and water; the water content is as high as 80%. Yet it shows rapid changes in stiffness under neural control. The dermis has been proposed to assume three mechanical states, soft, standard, and stiff. We investigated the relationship between the stiffness and the dermal mass and volume. Both the mass and volume decreased by 15% when the dermis stiffened from the standard state to the stiff state by mechanical stimulation and by chemical stimulation with potassium-rich seawater. The effect of the latter was abolished by anesthesia. The mass decrease was caused largely by water exudation. Tensilin, a holothurian protein that stiffens the soft dermis to form the standard state, did not cause any changes in mass. These results suggested that the stiffening mechanisms responsible for the transition from the soft state to the standard state, and that from the standard to the stiff state, are different. The removal of water from the dermis in the standard state, by soaking in hypertonic solution, caused only slight stiffening, which suggested that water exudation was not the direct cause of the stiffening. A change of pH of the surrounding medium, either more acidic or basic, was not associated with mass changes, although it caused a large increase in stiffness. The implications of the present results for the molecular mechanisms of the stiffness changes are discussed.
Oral and integumental uptake of free exogenous glycine by the Japanese spiny lobsterPanulirus japonicusphyllosoma larvae
Authors: Souza Juan Carlos Rodriguez , Strüssmann Carlos Augusto , Takashima Fumio , Satoh Hiroo , Sekine Shintaro , Shima Yasuhiro , Matsuda Hirokazu
Published: May 2010

The possibility of direct integumental absorption of the amino acid glycine from a solution in seawater was investigated in 250–260 day old (16.9–50.0 mg wet mass) phyllosoma larvae of the Japanese spiny lobster Panulirus japonicus Von Siebold 1824. The uptake of the amino acid was assessed by autoradiography and liquid scintillation counting (LSC) of larvae incubated with [2-3H]glycine and the net uptake was estimated by a time course high-performance liquid chromatography (HPLC) analysis of the concentration of glycine in the incubation medium. Autoradiography revealed the presence of labelled glycine in the cuticle, epidermis and internal tissues (digestive system, muscle, haemocytes) within 30 min of the onset of incubation. Absorption through the integument was confirmed by autoradiography and LSC as glycine uptake was observed even in larvae whose mouths were artificially sealed with cyanoacrylate bond prior to incubation. Scanning electron microscopic examination of the body surface revealed no bacterial population that could have mediated the uptake. HPLC revealed a consistent net uptake (0.29–0.39 μmol g−1 body mass h−1) of glycine in larvae incubated in 6 μmol l−1 glycine and high individual variation (e.g. absorption or release) in larvae incubated at higher concentrations (30 and 60 μmol l−1). Thus, the results of this study provide clear confirmation that, in addition to the known mode of oral feeding on macroscopic food masses, P. japonicus phyllosoma larvae are also able to absorb nutrients directly from the surrounding medium.
Orientation and autumn migration routes of juvenile sharp-tailed sandpipers at a staging site in Alaska
Authors: Grönroos Johanna , Muheim Rachel , Åkesson Susanne
Published: May 2010

Arctic waders are well known for their impressive long-distance migrations between their high northerly breeding grounds and wintering areas in the Southern hemisphere. Performing such long migrations requires precise orientation mechanisms. We conducted orientation cage experiments with juvenile sharp-tailed sandpipers (Calidris acuminata) to investigate what cues they rely on when departing from Alaska on their long autumn migration flights across the Pacific Ocean to Australasia, and which possible migration routes they could use. Experiments were performed under natural clear skies, total overcast conditions and in manipulated magnetic fields at a staging site in Alaska. Under clear skies the juvenile sharp-tailed sandpipers oriented towards SSE, which coincides well with reported sun compass directions from their breeding grounds in Siberia towards Alaska and could reflect their true migratory direction towards Australasia assuming that they change direction towards SW somewhere along the route. Under overcast skies the sandpipers showed a mean direction towards SW which would lead them to Australasia, if they followed a sun compass route. However, because of unfavourable weather conditions (headwinds) associated with overcast conditions, these south-westerly directions could also reflect local movements. The juvenile sharp-tailed sandpipers responded clearly to the manipulated magnetic field under overcast skies, suggesting the use of a magnetic compass for selecting their courses.
Rhythmic chewing with oral jaws in teleost fishes: a comparison with amniotes
Authors: Gintof Chris , Konow Nicolai , Ross Callum F. , Sanford Christopher P. J.
Published: May 2010

Intra-oral prey processing (chewing) using the mandibular jaws occurs more extensively among teleost fishes than previously documented. The lack of muscle spindles, γ-motoneurons and periodontal afferents in fishes makes them useful for testing hypotheses regarding the relationship between these sensorimotor components and rhythmic chewing in vertebrates. Electromyography (EMG) data from the adductor mandibulae (AM) were used to quantify variation in chew cycle duration in the bowfin Amia, three osteoglossomorphs (bony-tongues), four salmonids and one esocid (pike). All species chewed prey using their oral jaw in repetitive trains of between 3 and 30 consecutive chews, a pattern that resembles cyclic chewing in amniote vertebrates. Variance in rhythmicity was compared within and between lineages using coefficients of variation and Levene's test for homogeneity of variance. These comparisons revealed that some teleosts exhibit degrees of rhythmicity that are comparable to mammalian mastication and higher than in lepidosaurs. Moreover, chew cycle durations in fishes, as in mammals, scale positively with mandible length. Chewing among basal teleosts may be rhythmic because it is stereotyped and inflexible, the result of patterned interactions between sensory feedback and a central pattern generator, because the lack of a fleshy tongue renders jaw–tongue coordination unnecessary and/or because stereotyped opening and closing movements are important for controlling fluid flow in the oral cavity.
Functional physiology of lantern shark (Etmopterus spinax) luminescent pattern: differential hormonal regulation of luminous zones
Authors: Claes Julien M. , Mallefet Jérôme
Published: May 2010

Lantern sharks are small deep-sea sharks that harbour complex species-specific luminescent photophore patterns. The luminescent pattern of one of these sharks, Etmopterus spinax, is made up of nine luminous zones. Previous experiments revealed that in the largest of these zones (ventral zone), photophores are under hormonal control, light being triggered by both melatonin (MT) and prolactin (PRL). In this study, we analysed the luminescent responses to MT and PRL in five other luminous zones from 12 female and eight male E. spinax specimens. The results showed that all luminous zones respond to both hormones, with each zone having its own kinetic parameters (maximum light intensity, Lmax; total light emitted, Ltot; time from stimulation to Lmax, TLmax), which confirms the multifunctional character of this shark's luminescence. Ltot and Lmax were found to be directly dependent on the photophore density (PD) of the luminous zone, while TLmax varied independently from PD. In addition, we demonstrate a sexual dimorphism in the luminescent response to PRL, with male specimens having smaller Ltot and TLmax in the luminous zones from the pelvic region. As this region also harbours the sexual organs of this species, this strongly suggests a role for the luminescence from these zones in reproduction.
Myoglobin production in emperor penguins
Authors: Ponganis P. J. , Welch T. J. , Welch L. S. , Stockard T. K.
Published: May 2010

Increased oxygen storage is essential to the diving capacities of marine mammals and seabirds. However, the molecular mechanisms underlying this adaptation are unknown. Myoglobin (Mb) and Mb mRNA concentrations were analyzed in emperor penguin (Aptenodytes forsteri) adults and chicks with spectrophotometric and RNase protection assays to evaluate production of their large Mb-bound O2 stores. Mean pectoral Mb concentration and Mb mRNA content increased throughout the pre-fledging period and were 15-fold and 3-fold greater, respectively, in adults than in 3.5 month old chicks. Mean Mb concentration in 5.9 month old juveniles was 2.7±0.4 g 100 g−1 muscle (44% that of wild adults), and in adults that had been captive all their lives it was 3.7±0.1 g 100 g−1 muscle. The Mb and Mb mRNA data are consistent with regulation of Mb production at the level of transcription as in other animals. Significant Mb and Mb mRNA production occurred in chicks and young juveniles even without any diving activity. The further increase in adult Mb concentrations appears to require the exercise/hypoxia of diving because Mb concentration in captive, non-diving adults only reached 60% of that of wild adults. The much greater relative increase in Mb concentration than in Mb mRNA content between young chicks and adults suggests that there is not a simple 1:1 relationship between Mb mRNA content and Mb concentration. Nutritional limitation in young chicks and post-transcriptional regulation of Mb concentration may also be involved.
Insects running on elastic surfaces
Authors: Spence Andrew J. , Revzen Shai , Seipel Justin , Mullens Chris , Full Robert J.
Published: May 2010

In nature, cockroaches run rapidly over complex terrain such as leaf litter. These substrates are rarely rigid, and are frequently very compliant. Whether and how compliant surfaces change the dynamics of rapid insect locomotion has not been investigated to date largely due to experimental limitations. We tested the hypothesis that a running insect can maintain average forward speed over an extremely soft elastic surface (10 N m−1) equal to 2/3 of its virtual leg stiffness (15 N m−1). Cockroaches Blaberus discoidalis were able to maintain forward speed (mean ± s.e.m., 37.2±0.6 cm s−1 rigid surface versus 38.0±0.7 cm s−1 elastic surface; repeated-measures ANOVA, P=0.45). Step frequency was unchanged (24.5±0.6 steps s−1 rigid surface versus 24.7±0.4 steps s−1 elastic surface; P=0.54). To uncover the mechanism, we measured the animal's centre of mass (COM) dynamics using a novel accelerometer backpack, attached very near the COM. Vertical acceleration of the COM on the elastic surface had a smaller peak-to-peak amplitude (11.50±0.33 m s−2, rigid versus 7.7±0.14 m s−2, elastic; P=0.04). The observed change in COM acceleration over an elastic surface required no change in effective stiffness when duty factor and ground stiffness were taken into account. Lowering of the COM towards the elastic surface caused the swing legs to land earlier, increasing the period of double support. A feedforward control model was consistent with the experimental results and provided one plausible, simple explanation of the mechanism.
Closed-Form Solutions for a Piecewise Quadratic Half-Plane Contact Problem
Authors: Davies M , Hills D A
Published: May 2010

A procedure for the solution of a general half-plane contact problem in which the geometry is specified in a piecewise quadratic sense is developed, in a form particularly suitable for implementation using an algebraic manipulator. This makes feasible the possibility of determining a closed-form solution when the number of contact segments is small, and opens up the possibility of exploring the strength of a wide range of contacting profiles.
Experimental study of multiple-channel automotive underbody diffusers
Authors: Jowsey L , Passmore M
Published: May 2010

Underbody diffusers are used widely in race car applications because they can significantly improve the cornering capacity of the vehicle through the generation of a downforce. They are also likely to have a wider role in reducing the drag in road vehicles as it becomes increasingly important to reduce emissions of carbon dioxide.

This paper reports on a wind tunnel investigation, using a simplified bluff body model, into the effect of splitting a simple plane diffuser into multiple channels. Tests are reported for a range of diffuser geometries suitable for road and race car applications. The results for the lift, the drag, and the incremental changes to the lift-to-drag ratio are reported and discussed in terms of the underbody pressures.

While broadly similar trends to the single-channel plane diffuser are seen in the multiple-channel diffuser configurations, it was found that the effect of increasing the number of channels depended on the flow regimes present in the plane diffuser. At angles just above the plane diffuser optimum, where the flow is partially separated, the multiple-channel configurations give large improvements in the downforce with minimal increase in the drag, significantly extending the performance envelope. The pressure maps indicate that the gains occur through improved diffuser pumping and pressure recovery in both the inner and the outer channels.
Application of automotive driving simulators for sound and vibration research
Authors: Genuit K , Fiebig A
Published: May 2010

Noise vibration harshness (NVH) issues are still a very important topic in the automotive industry, where the avoidance of disturbing noises and the creation of highest acoustical comfort and perceived NVH-quality are important targets. In this context, it is becoming more widely understood that sound and vibration must not only be considered as disturbing elements regarding NVH-comfort. They can be used to develop an acoustic and vibration environment, which positively influences customer satisfaction. The creation of sounds (and vibrations), which give the impression of high product quality, helps manufacturers to stand out against their competitors and to meet increasing requirements. The research of sound and vibration is difficult and numerous methods, theories, and simulations have been developed to obtain a deeper understanding of multi-sensory perception. The present paper reviews current sound and vibration studies and introduces established as well as novel concepts and theories. Moreover, the meaning of driving simulators for sound and vibration studies will be discussed. Finally, experimental results will be shown to underline the complexity and future challenges in the scope of automotive applications regarding multi-sensory perception. Overall, it was found that evaluations differ depending on context and test situation; even the presented stimuli are almost identical. Such effects have to be considered with respect to the selection of the test method and test surrounding as well as concerning the interpretation of test results.
Multi-sensory congruence in vehicle sound quality assessment: Effects of vibration and irrelevant emotional primes on affective reactions and evaluations of product sounds
Authors: Genell A , Västfjäll D , Schmelzle C , Kleiner M
Published: May 2010

A listening test was performed where a group of professional truck drivers were asked to rate their impressions of binaurally recorded interior truck sound of different levels, while subjected to different vibration levels in the steering wheel and in the foot rest of a truck simulator. The hypothesis was that, if the sound and vibrations had the same relative levels as the original environment inside a real truck cabin, the emotional reactions would not be as negative as if either of the modalities was significantly increased relative to the other. The results indicate some support for this hypothesis. In addition, the effects of irrelevant emotional primes on sound quality assessment were studied. The results are discussed in relation to multi-modal theories of emotional sound design for vehicle interiors.
Optimal shape design of a brake calliper for squeal noise reduction considering system instability
Authors: Soh H J , Yoo J-H
Published: May 2010

Squeal is a noise phenomenon occurring in the last stage of automobile braking with a high-frequency sound. It is very difficult to express the phenomenon using a mathematical model, since the origin of squeal noise is physically complex. However, the possibility of squeal generation can be predicted by solving the vibration equation of the self-excited system using the complex eigenvalue analysis method. The results of the method are expressed as the magnitude of the unstable mode, and the generation of squeal noise can be prevented by reducing the magnitude of the unstable mode of the brake system. The objective of this research is to determine the optimal design process focused on the calliper housing shape to suppress squeal noise generation by reducing the system instability. The objective function is set to minimize the real part of the complex eigenvalue, i.e. the instability index. In the optimization design process, the design variable for topology optimization is established by focusing on the finger part of the calliper housing, which transmits the braking pressure to the pad lining. To supplement the complex shape generated by the topology optimization process, parametric design variables are selected for the subsequent process. Parameters are set to adjust the housing finger stiffness and are defined by considering the topology optimization result. Finally, the asymmetric shape of the calliper housing is obtained to reduce squeal noise generation.
Facilitating the driver detection of road surface type by selective manipulation of the steering-wheel acceleration signal
Authors: Berber-Solano T P , Ajovalasit M , Giacomin J
Published: May 2010

Previous research has investigated the possibility of facilitating the driver detection of road surface type by means of selective manipulation of the steering-wheel acceleration signal. In previous studies a selective increase in acceleration amplitude has been found to facilitate road-surface-type detection, as has selective manipulation of the individual transient events which are present in the signal. The previous research results have been collected into a first guideline for the optimization of the steering-wheel acceleration signal, and the guideline has been tested in the current study. The test stimuli used in the current study were ten steering-wheel acceleration—time histories which were selected from an extensive database of road test measurements performed by the research group. The time histories, which were all from midsized European automobiles and European roads, were selected such that the widest possible operating envelope could be achieved in terms of the r.m.s. value of the steering acceleration, the kurtosis, the power spectral density function, and the number of transient events present in the signal. The time histories were manipulated by means of the mildly non-stationary mission synthesis algorithm in order to increase, by a factor of 2, both the number and the size of the transient events contained within the frequency interval from 20 Hz to 60 Hz. The ensemble, composed of both the unmanipulated and the manipulated time histories, was used to perform a laboratory-based detection task with 15 participants, who were presented the individual stimuli in random order. The participants were asked to state, by answering ‘yes’ or ‘no’, whether each stimulus was considered to be from the road surface that was displayed in front of them by means of a large photograph on a board. The results suggest that the selectively manipulated steering-wheel acceleration stimuli produced improved detection for eight of the ten road surface types which were tested, with a maximum improvement of 14 per cent in the case of the broken road surface. The selective manipulation did lead, however, to some degradation in detection for the motorway road stimulus and for the noise road stimulus, thus suggesting that the current guideline is not universally optimal for all road surfaces.
Factors affecting the decomposition of biodiesel under simulated engine sump oil conditions
Authors: Bannister C D , Chuck C J , Hawley J G , Price P , Chrysafi S S
Published: May 2010

Biodiesel is a renewable fuel derived from plant, waste, or algal oils. It is synthesized by the transesterification of triglycerides with an alcohol to yield fatty acid alkyl esters. These esters are prone to oxidative deterioration, yielding a variety of products which increase the viscosity of the fuel beyond acceptable levels. A proportion of the fuel used will always find its way into the vehicle's lubricating oil with dilution becoming increasingly significant on vehicles equipped with a particulate filter because late injections lead to increased wall wetting. Biodiesel will also accumulate in the lubricating oil but, unlike mineral diesel, the biodiesel will not evaporate at the normal operating temperature of the oil and will instead accumulate. As the biodiesel oxidizes within the oil, degradation products will eventually form, leading to a significant increase in the oil viscosity with a potential impact on base engine durability. This study investigates the relative effects of a number of factors likely to be relevant to biodiesel oxidation within a simulated engine lubrication oil environment. The findings of this study suggest that determining the point at which oxidation occurs is inherently difficult and the impact of various factors can vary depending on the oxidation indicator examined. The most significant factors in total oxidation were found to be the temperature and air flowrate with other factors, such as the presence of iron and pro-oxidant, having a significant impact only after initial oxidation reactions had occurred.
Influence of tyre pressure on an urban bus transient and steady state handling performance
Authors: Al-Solihat M K , Rakheja S , Ahmed A K W
Published: May 2010

The influence of the variation in the tyre inflation pressure on the steady state and transient handling dynamics of an urban bus are investigated through analysis of a three-dimensional (3D) vehicle model. A five-degrees-of-freedom handling dynamic model of the bus is formulated incorporating the non-linear models of the suspension components and the tyre. The vertical stiffness properties of the tyre are characterized through a regression model under normal load and the inflation pressure that was formulated on the basis of the laboratory measured data. The available tyre data on the cornering properties of tyres are analysed to derive a modified ‘magic formula’ for predicting the cornering properties as functions of the inflation pressure and the normal load. The proposed model responses showed reasonably good agreement with the available measured data over ranges of the inflation pressures and normal loads. The 3D handling dynamic model was subsequently analysed under sinusoidal and ramp-step steering inputs to study the influence of the tyre pressure on the steady state and transient handling responses. The results show notable influences of the tyre pressures on both the steady state and the transient handling properties.