bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Speed Ship Manoeuvrability: Mathematical Model and its Simulation
Authors: Oh Kyoung-Gun , Hasegawa Kazuhiko
Published: November 2013

In case of offshore support vessels, it is quite important for their behaviours in low speed manoeuvrability. It is not easy to operate offshore support vessels and it raises an importance to train crew by a ship handling simulator. Therefore it is quite hot issue for ship handling simulator vendors to provide mathematical model of support vessels, but from the users’ point-of-view the model used for the simulator is not clear. Up to now some mathematical models are proposed in the literature, but the validation is not yet done carefully. For example, cross flow model is the main part for hydrodynamic force in low speed ship manoeuvring. From model ship experiments of various types of ships and from some comparison study, it is found that further discussion is necessary. In this paper, sway force and yaw moment as well as surge force will be treated in low speed condition with certain sway and yaw motions. There are many experiment results for such hydrodynamic forces and moment, especially for sway force and yaw moment, for sway motion, but those for yaw motion is quite limited.

In this paper, such hydrodynamic forces and moment for both sway and yaw motions are calculated and validated with experiment results. Some manoeuvring simulation will also demonstrate which terms and/or expressions in the mathematical model are affecting the motion.
Free Field Sediment Mobility on Australia’s North West Shelf
Authors: Mohr Henning , Draper Scott , White David
Published: November 2013

Under cyclonic conditions, sediment on the North West Shelf (NWS) of Australia may become mobile in shallow water due to classical sediment transport or local liquefaction, and this can affect, for example, the on-bottom stability of subsea pipelines. In this paper, three calcareous sediments sampled from the NWS are analysed, together with realistic metocean data, to illustrate this potential for sediment mobility on the NWS. Specifically, experiments are performed in a recirculating flume (known as an O-Tube) to measure the erosional behaviour and an additional series of experiments are performed using a shaking table, on which each of the sediments have been liquefied and excess pore pressure measurements recorded to back calculate the consolidation coefficient. Soil characterisation data, threshold velocity measurements and shaking table results have then combined to illustrate the potential for sediment mobility for each of the NWS sediments. Best practice models are used to calculate wave and current combined shear stress at the seabed and excess pore pressure accumulation. We find that for these sediments, freshly deposited in laboratory samples, mobility due to sediment transport or liquefaction is very likely in cyclonic conditions on the NWS. Liquefaction is most likely for loosely packed silt, whilst sediment transport is most likely for sand. However, we also show that in more extreme cyclonic conditions there are a subset of sediments that can become mobile due to both sediment transport and liquefaction.
Numerical Modelling of a Heaving Point Absorber in Front of a Vertical Wall
Authors: Schay Julius , Bhattacharjee Joydip , Guedes Soares C.
Published: November 2013

The hydrodynamic performance of a heaving point absorber as a wave energy converter near a large body is studied through numerical modeling. First the study is performed for an individual point absorber in the absence of large structure and the results are compared with the results available in the literature. Next, the performance of a point absorber floating in the vicinity of a large body, which is considered as a fixed vertical wall, is investigated. The efficiency of the power absorption in regular and irregular seas is examined based on different floater sizes, floater shapes, drafts, wave heading angle and positioning of the floater. Numerical simulations are based on hydrodynamic forces and coefficients, obtained with the commercial software WAMIT.
Effect of Reeling Installation on Weld Residual Stress in Pipeline Girth Welds
Authors: Sriskandarajah T. , Roberts Graeme , Zhou Daowu
Published: November 2013

A characteristic of pipeline installation by the reeling technique is the generation of high plastic strain around the majority of the pipeline’s circumference as it is spooled onto a drum, under displacement controlled conditions. It is well-known that the application of sufficiently high amounts of mechanical or thermal energy will “anneal” (relax) weld residual stresses and, therefore, under the gross plasticity experienced during reeling it should be expected that initial girth weld residual stresses will be entirely relaxed during the first reel cycle.

The residual stress state needs to be taken into account in Engineering Critical Assessment (ECA) procedures of girth welds when predicting allowable defect dimensions. ECA codes such as DNV-OS-F101 and BS7910 assume the welding residual stress to be equal to the yield strength of the parent material and relaxation of welding residual stress under overload is allowed. However, the treatment specified in DNV is established from load-controlled scenarios and may result in un-realistic allowable defect dimensions in displacement-controlled situations such as reeling.

Welding residual stress in reeling ECA is concerning to the subsea pipeline industry. By performing reeling simulations with 3D finite element analyses (FEA), this paper examines the welding residual stress before and after reeling and assesses the extent of residual stress relaxation. It was found that reeling axial strain causes significant relaxation of the weld residual stress at the pipe intrados and extrados. At the saddle points there is a slight disruption to the residual stress field. The full weld residual stress is relaxed from a value equal to the material yield stress, and is replaced by a plastic deformation induced stress of much lower magnitude, typically in the order of 100 MPa or less. The plastic deformation stress is of equal magnitude whether or not the pipe section contains initial weld residual stress and, therefore, it is concluded that weld residual stress can be ignored following the first reel cycle.
Research on Wind Wave Considering Nonlinear Dispersion Effect
Authors: Shu Xiejun , Hou Peng , Zhuang Hua , Zhao Mingli
Published: November 2013

Understanding of the offshore wind wave status plays a guiding role in surrounding marine engineering constructions, marine traffic, sea farming, etc. Further study is beneficial to marine economy development, as well as to the academic value of wave theory.

This paper primarily introduces the deduction of new wind wave growth relations. Firstly, a new relation formula between wave steepness and wave age was deduced by combining the 3/2 power law developed by Toba with the nonlinear dispersion relation deduced by Li, and by ignoring the effect of water depth. And when the higher-order term was ignored, the relation formula can be simplified as that based on linear dispersion. Secondly, based on the combination of this new relation formula with the significant wave energy balance equation, new wind wave growth relation formulae including the wave non-linear dispersion effect were deduced. When the deduced growth relation formulae were applied in offshore area of Jiangsu incorporating with Mitsuyasu’s empirical formula about the open sea fetch and wind speed, accurate open sea wave parameters of Jiangsu can be formulated by only considering one parameter, such as wind speed. Overall, as this methodology avoided the uncertainty about the fetch of open ocean and operation error during the calculation process, results gained from this report had higher accuracy than other published formulae, and results were validated by NCEP reanalyzing data of Jiangsu offshore area and other researches.
Uniaxial and Triaxial Stress-Strain Behaviour of Ductile Cement Pastes Reinforced With Wollastonite Microfibers
Authors: Vitorino Fabrício de C. , Toledo Filho Romildo D.
Published: November 2013

When an oil well is submitted to cyclic steam injection the heating process induces tensile stresses in the cement sheath due to the thermal gradient that take place leading to cement-steel debonding and/or cement cracking. Similar problem can occur if the cement sheath is submitted to high creep deformations coming from the adjacent rock (this is the case for example of oil exploration in salt domes). In both cases sheath cracking can result in loss of hydraulic isolation and consequently in excessive water production with undesired economic and environmental consequences. In order to deal with this challenging scenario oil well cementing systems of special properties (e.g. high tensile strength, low elastic modulus and elevated toughness) should be used as an alternative to conventional high compressive strength systems. In this study cement pastes of high ductility were developed using wollastonite micro-fibers as reinforcement. The mixtures were developed within the framework of the Compressive Packing Model [1] and wollastonite microfibers were added in volume fractions of 2.5, 5.0 and 7.5 %. Uniaxial and triaxial compressive tests were carried out to obtain the unconfined and confined stress-strain behavior of the composites. The crack initiation stress and strain and the fracture process of the pastes under unconfined stress will be reported in this paper. Triaxial tests were performed under confining pressures of 0, 600 and 1200 psi and the Mohr-Coulomb criteria assumed to determine the internal frictional angle and cohesion. The results show that the addition of wollastonite microfibers increased the compressive strength of the pastes keeping the same strain capacity of the matrix. The internal frictional angle was also increased with the increase in the fiber volume fraction. However, the cohesion of the paste was reduced with the fiber addition.
Real-Time Riser Fatigue Monitoring Routine: Architecture, Data and Results
Authors: McNeill Scot , Agarwal Puneet , Kluk Dan , Bhalla Kenneth , Saruhashi Tomokazu , Sawada Ikuo , Kyo Masanori , Miyazaki Eigo , Yamazaki Yasuyuki
Published: November 2013

Recently, the Modal Decomposition and Reconstruction (MDR) algorithm was developed to accurately estimate fatigue damage in marine risers based on measured acceleration and angular rates at several locations. The greatest benefit for drilling risers can be derived by incorporating the method in an online, fully automated system. In this way, fatigue damage estimates are available to the crew on the rig in real-time for risk quantification and mitigation.

To this end, the MDR routine was implemented for online assessment of fatigue damage along the entire riser from acceleration and angular rate measurements at typically 5–10 elevations. This paper discusses the architecture, highlights some measured data and provides results for modes, stress and fatigue damage rate for the Chikyu drilling vessel during two scientific drilling campaigns. These campaigns occurred at the Shimokita site (1180-meter water depth) and the Nankai trough site (1939-meter water depth). To the authors’ knowledge, real-time fatigue monitoring of the entire riser has not been accomplished previously.

Robust incorporation of the MDR algorithm into an online computational environment is detailed, including incorporation of top tension and mud weight data from the rig, detection and removal of data errors, and streamlined flow of the data through the computational modules. Subsequently, it is shown by example how the measured accelerations and angular rates are used to determine excited modes, participating modes, stress distribution and fatigue damage along the entire Chikyu drilling riser in an online setting.

The technology highlighted advances riser integrity management two steps forward by first using measured data at 5–10 locations and the MDR algorithm to reconstruct stress and fatigue damage along the entire riser, and secondly integrating this approach into a fully automated, real-time computational environment. As a result, drilling engineers are empowered with a tool that provides real-time data on the integrity of the drilling riser, enabling informed decisions to be made in adverse current or wave conditions. Measured data also serves as a benchmark for analytical model calibration activities, reducing conservatism in stress and fatigue in future deployments. Furthermore, cumulative fatigue damage can be tracked in each riser joint, enabling more effective joint rotation and inspection programs.
Simulation of Horizontal-Axis Tidal Turbine Wakes Using a Coupled Approach With Rankine-Froude Actuator Disk Model and a Weakly-Compressible Finite Volume Solver
Authors: Elie B. , Oger G. , Guillerm P.-E. , Alessandrini B.
Published: November 2013

This paper presents the early work that has been achieved in the perspective of developing a tidal farm simulation tool. First a horizontal-axis tidal turbine (HATT) simulation model coupled with a Finite Volume solver is introduced. This model is based on the classical actuator disk theory (Rankine and Froude, 19th century). Then the fluid model adopted in our approach is presented and discussed. This model relies on a Finite Volume solver applied to a fully-cartesian grid, and is based on weakly-compressible explicit Navier-Stokes equations. The first results obtained on the wake are presented and discussed in order to quantify the accuracy and the validity of this approach.
RAR Scars Bone Marrow
Authors: Berndt Jason D.
Published: November 2013

A genetic mouse model of the bone disease myelofibrosis indicates that excessive retinoic acid signaling may be responsible.
Autophagy for Better Heart Health
Authors: Wong Wei
Published: November 2013

Decreasing the activity of the Hippo pathway kinase Mst1 to promote autophagy could be used to treat heart failure.
Clinical Experience of Colistin-Glycopeptide Combination in Critically Ill Patients Infected with Gram-Negative Bacteria
Authors: Petrosillo Nicola , Giannella Maddalena , Antonelli Massimo , Antonini Mario , Barsic Bruno , Belancic Laura , Inkaya A. Cagkan , De Pascale Gennaro , Grilli Elisabetta , Tumbarello Mario , Akova Murat
Published: November 2013

A colistin-glycopeptide combination (CGC) has been shown
in vitro
to be synergistic against multidrug-resistant Gram-negative bacteria (MDR GNB), especially
Acinetobacter baumannii
, and to prevent further resistance. However, clinical data are lacking. We carried out a retrospective multicenter study of patients hospitalized in intensive care units (ICUs) who received colistin for GNB infection over a 1-year period, to assess the rates of nephrotoxicity and 30-day mortality after treatment onset among patients treated with and without CGC for ≥48 h. Of the 184 patients treated with colistin, GNB infection was documented for 166. The main causative agents were MDR
A. baumannii
(59.6%), MDR
Pseudomonas aeruginosa
(18.7%), and carbapenem-resistant
Klebsiella pneumoniae
(14.5%); in 16.9% of patients, a Gram-positive bacterium (GPB) coinfection was documented. Overall, 68 patients (40.9%) received CGC. Comparison of patients treated with and without CGC showed significant differences for respiratory failure (39.7% versus 58.2%), ventilator-associated pneumonia (54.4% versus 71.4%), MDR
A. baumannii
infection (70.6% versus 52%), and GPB coinfection (41.2% versus 0%); there were no differences for nephrotoxicity (11.8% versus 13.3%) and 30-day mortality (33.8% versus 29.6%). Cox analysis performed on patients who survived for ≥5 days after treatment onset showed that the Charlson index (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.01 to 1.44;
P
= 0.001) and MDR
A. baumannii
infection (HR, 2.51; 95% CI, 1.23 to 5.12;
P
= 0.01) were independent predictors of 30-day mortality, whereas receiving CGC for ≥5 days was a protective factor (HR, 0.42; 95% CI, 0.19 to 0.93;
P
= 0.03). We found that CGC was not associated with higher nephrotoxicity and was a protective factor for mortality if administered for ≥5 days.
Antimicrobial Activity of Solithromycin against Clinical Isolates of Legionella pneumophila Serogroup 1
Authors: Mallegol Julia , Fernandes Prabhavathi , Melano Roberto G. , Guyard Cyril
Published: November 2013

The activity of solithromycin was evaluated against clinical
Legionella pneumophila
serogroup 1 (Lp1) isolates (
n
= 196) collected in Ontario, Canada, from 1980 to 2011. Its
in vitro
activity was compared to that of azithromycin (AZM) using the broth microdilution method. Solithromycin had a MIC
50
of ≤0.015 μg/ml and a MIC
90
of 0.031 μg/ml, making its activity at least 8-fold to 32-fold higher than that of AZM (MIC
50
and MIC
90
, 0.125 μg/ml and 1 μg/ml, respectively). Ninety-nine percent of the isolates had MICs for solithromycin ranging from ≤0.015 μg/ml to 0.031 μg/ml, whereas 83.6% of the isolates showed MICs for AZM ranging from 0.062 μg/ml to 0.25 μg/ml. Interestingly, 96.7% (30 out of 31 clinical isolates) identified with higher AZM MICs (0.5 μg/ml to 2 μg/ml) belonged to the clinically prevalent sequence type 1. To investigate the intracellular activity of solithromycin,
in vitro
invasion assays were also performed against a subset of representative Lp1 isolates internalized within human lung epithelial cells. Solithromycin and AZM both inhibited growth of all intracellular Lp1 isolates at 1× or 8× MICs, displaying bacteriostatic effects, as would be expected with protein synthesis inhibitor rather than bactericidal activity. Solithromycin demonstrated the highest
in vitro
and intracellular potency against all Lp1 isolates compared to AZM. Given the rapid spread of resistance mechanisms among respiratory pathogens and the reported treatment failures in legionellosis, the development of this new fluoroketolide, already in phase 3 oral clinical studies, constitutes a promising alternative option for the treatment of legionellosis.
More Complications Occur in Macrolide-Resistant than in Macrolide-Sensitive Mycoplasma pneumoniae Pneumonia
Authors: Zhou Yunlian , Zhang Yuanyuan , Sheng Yuanjian , Zhang Li , Shen Zheng , Chen Zhimin
Published: November 2013

We sought to understand the situation of macrolide-resistant genotypes of
Mycoplasma pneumoniae
, and analyze the relationship between macrolide-resistant genotypes and clinical manifestations of
Mycoplasma pneumoniae
pneumonia (MPP). Full-length sequencing of the 23S rRNA gene of
M. pneumoniae
was performed in 235 nasopharyngeal aspirates (NPAs) from children with MPP. We also retrospectively compared the clinical characteristics of macrolide-resistant (MR)
M. pneumoniae
infections and macrolide-sensitive (MS)
M. pneumoniae
infections. A total of 206 patients had point mutations in the
M. pneumoniae
23S rRNA gene, and these patients are referred to as MR patients. The remaining 29 patients without point mutations are referred to as MS patients. Among 206 MR patients, 199 (96.6%) had A2063G mutations, 6 had A2063T mutations, and the remaining patients had an A2064G mutation. Among the clinical manifestations, we found that the median fever durations were 8 days (range, 0 to 42 days) and 6 days (0 to 14 days) (
P
< 0.01), the median hospitalization durations were 8 days (2 to 45 days) and 6 days (3 to 16 days) (
P
< 0.01), and the median fever durations after macrolide therapy were 5 days (0 to 42 days) and 3 days (0 to 10 days) (
P
< 0.01), respectively, in the MR and MS groups. We also found that the incidence of extrapulmonary complications in the MR group was significantly higher than that in the MS group (
P
< 0.05). Moreover, the radiological findings were more serious in the MR group than in the MS group (
P
< 0.05). The increasing prevalence of MR
M. pneumoniae
has become a significant clinical issue in the pediatric patients, which may lead to more extrapulmonary complications and severe clinical features and radiological manifestations.
Contribution of β-Lactamases and Porin Proteins OmpK35 and OmpK36 to Carbapenem Resistance in Clinical Isolates of KPC-2-Producing Klebsiella pneumoniae
Authors: Zhang Ying , Jiang Xiaofei , Wang Yanyan , Li Gang , Tian Yueru , Liu Hong , Ai Fuqi , Ma Yiming , Wang Bei , Ruan Feiyi , Rajakumar Kumar
Published: November 2013

Fifty-seven carbapenem-resistant
Klebsiella pneumoniae
isolates belonging to ST11 (50 isolates), ST423 (5 isolates), and two other sequence types were studied. All were positive for
bla
KPC-2
,
bla
TEM-1
, and
bla
CTX-M-14
. SDS-PAGE analysis of six representative isolates demonstrated varied porin expression. Nevertheless, when
bla
KPC-2
was deleted, carbapenem resistance was markedly reduced. Additionally, SHV-12, DHA-1, and/or VIM-1 appeared to contribute to accessory carbapenemase activity. In contrast, OmpK35 and/or OmpK36 deficiency seemed to serve only as a minor cooperative factor.
The Vps/VacJ ABC Transporter Is Required for Intercellular Spread of Shigella flexneri
Authors: Carpenter Chandra D. , Cooley Benjamin J. , Needham Brittany D. , Fisher Carolyn R. , Trent M. Stephen , Gordon Vernita , Payne Shelley M.
Published: November 2013

The Vps/VacJ ABC transporter system is proposed to function in maintaining the lipid asymmetry of the outer membrane. Mutations in
vps
or
vacJ
in
Shigella flexneri
resulted in increased sensitivity to lysis by the detergent sodium dodecyl sulfate (SDS), and the
vpsC
mutant showed minor differences in its phospholipid profile compared to the wild type.
vpsC
mutants were unable to form plaques in cultured epithelial cells, but this was not due to a failure to invade, to replicate intracellularly, or to polymerize actin via IcsA for movement within epithelial cells. The addition of the outer membrane phospholipase gene
pldA
on a multicopy plasmid in a
vpsC
or
vacJ
mutant restored its resistance to SDS, suggesting a restoration of lipid asymmetry to the outer membrane. However, the
pldA
plasmid did not restore the mutant's ability to form plaques in tissue culture cells. Increased PldA levels also failed to restore the mutant's phospholipid profile to that of the wild type. We propose a dual function of the Vps/VacJ ABC transporter system in
S. flexneri
in both the maintenance of lipid asymmetry in the outer membrane and the intercellular spread of the bacteria between adjacent epithelial cells.
An Escherichia coli Nissle 1917 Missense Mutant Colonizes the Streptomycin-Treated Mouse Intestine Better than the Wild Type but Is Not a Better Probiotic
Authors: Adediran Jimmy , Leatham-Jensen Mary P. , Mokszycki Matthew E. , Frimodt-Møller Jakob , Krogfelt Karen A. , Kazmierczak Krystyna , Kenney Linda J. , Conway Tyrrell , Cohen Paul S.
Published: November 2013

Previously we reported that the streptomycin-treated mouse intestine selected for two different
Escherichia coli
MG1655 mutants with improved colonizing ability: nonmotile
E. coli
MG1655
flhDC
deletion mutants that grew 15% faster
in vitro
in mouse cecal mucus and motile
E. coli
MG1655
envZ
missense mutants that grew slower
in vitro
in mouse cecal mucus yet were able to cocolonize with the faster-growing
flhDC
mutants. The
E. coli
MG1655
envZ
gene encodes a histidine kinase that is a member of the
envZ-ompR
two-component signal transduction system, which regulates outer membrane protein profiles. In the present investigation, the
envZ
P41L
gene was transferred from the intestinally selected
E. coli
MG1655 mutant to
E. coli
Nissle 1917, a human probiotic strain used to treat gastrointestinal infections. Both the
E. coli
MG1655 and
E. coli
Nissle 1917 strains containing
envZ
P41L
produced more phosphorylated OmpR than their parents. The
E. coli
Nissle 1917 strain containing
envZ
P41L
also became more resistant to bile salts and colicin V and grew 50% slower
in vitro
in mucus and 15% to 30% slower on several sugars present in mucus, yet it was a 10-fold better colonizer than
E. coli
Nissle 1917. However,
E. coli
Nissle 1917
envZ
P41L
was not better at preventing colonization by enterohemorrhagic
E. coli
EDL933. The data can be explained according to our “restaurant” hypothesis for commensal
E. coli
strains, i.e., that they colonize the intestine as sessile members of mixed biofilms, obtaining the sugars they need for growth locally, but compete for sugars with invading
E. coli
pathogens planktonically.
Predicting sickness during a 2-week soccer camp at 3600 m (ISA3600)
Authors: Buchheit Martin , Simpson Ben M , Schmidt Walter F , Aughey Robert J , Soria Rudy , Hunt Robert A , Garvican-Lewis Laura A , Pyne David B , Gore Christopher J , Bourdon Pitre C
Published: November 2013

Objectives

To examine the time course of changes in wellness and health status markers before and after episodes of sickness in young soccer players during a high-altitude training camp (La Paz, 3600 m).

Methods

Wellness and fatigue were assessed daily on awakening using specifically-designed questionnaires and resting measures of heart rate and heart rate variability. The rating of perceived exertion and heart rate responses to a submaximal run (9 km/h) were also collected during each training session. Players who missed the morning screening for at least two consecutive days were considered as sick.

Results

Four players met the inclusion criteria. With the exception of submaximal exercise heart rate, which showed an almost certain and large increase before the day of sickness (4%; 90% confidence interval 3 to 6), there was no clear change in any of the other psychometric or physiological variables. There was a very likely moderate increase (79%, 22 to 64) in self-reported training load the day before the heart rate increase in sick players (4 of the 4 players, 100%). In contrast, training load was likely and slightly decreased (−24%, −78 to −11) in players who also showed an increased heart rate but remained healthy.

Conclusions

A >4% increased heart rate during submaximal exercise in response to a moderate increase in perceived training load the previous day may be an indicator of sickness the next day. All other variables, that is, resting heart rate, heart rate variability and psychometric questionnaires may be less powerful at predicting sickness.
Methods of the international study on soccer at altitude 3600 m (ISA3600)
Authors: Gore Christopher J , Aughey Robert J , Bourdon Pitre C , Garvican-Lewis Laura A , Soria Rudy , Claros Jesus C Jimenez , Sargent Charli , Roach Gregory D , Buchheit Martin , Simpson Ben M , Hammond Kristal , Kley Marlen , Wachsmuth Nadine , Pepper Mark , Edwards Alistair , Cuenca Douglas , Vidmar Tony , Spielvogel Hilde , Schmidt Walter F
Published: November 2013

Background

We describe here the 3-year process underpinning a multinational collaboration to investigate soccer played at high altitude—La Paz, Bolivia (3600 m). There were two main aims: first, to quantify the extent to which running performance would be altered at 3600 m compared with near sea level; and second, to characterise the time course of acclimatisation of running performance and underlying physiology to training and playing at 3600 m. In addition, this project was able to measure the physiological changes and the effect on running performance of altitude-adapted soccer players from 3600 m playing at low altitude.

Methods

A U20 Bolivian team (‘The Strongest’ from La Paz, n=19) played a series of five games against a U17 team from sea level in Australia (The Joeys, n=20). 2 games were played near sea level (Santa Cruz 430 m) over 5 days and then three games were played in La Paz over the next 12 days. Measures were (1) game and training running performance—including global positioning system (GPS) data on distance travelled and velocity of movement; (2) blood—including haemoglobin mass, blood volume, blood gases and acid–base status; (3) acclimatisation—including resting heart rate variability, perceived altitude sickness, as well as heart rate and perceived exertion responses to a submaximal running test; and (4) sleep patterns.

Conclusions

Pivotal to the success of the project were the strong professional networks of the collaborators, with most exceeding 10 years, the links of several of the researchers to soccer federations, as well as the interest and support of the two head coaches.
On the use of mobile inflatable hypoxic marquees for sport-specific altitude training in team sports
Authors: Girard Olivier , Brocherie Franck , Millet Grégoire P
Published: November 2013

Background/aim

With the evolving boundaries of sports science and greater understanding of the driving factors in the human performance physiology, one of the limiting factors has now become the technology. The growing scientific interest on the practical application of hypoxic training for intermittent activities such as team and racket sports legitimises the development of innovative technologies serving athletes in a sport-specific setting.

Methods

Description of a new mobile inflatable simulated hypoxic equipment.

Results

The system comprises two inflatable units—that is, a tunnel and a rectangular design, each with a 215 m3volume and a hypoxic trailer generating over 3000 Lpm of hypoxic air with FiO2between 0.21 and 0.10 (a simulated altitude up to 5100 m). The inflatable units offer a 45 m running lane (width=1.8 m and height=2.5 m) as well as a 8 m×10 m dome tent. FiO2is stable within a range of 0.1% in normal conditions inside the tunnel. The air supplied is very dry—typically 10–15% relative humidity.

Conclusions

This mobile inflatable simulated hypoxic equipment is a promising technological advance within sport sciences. It offers an opportunity for team-sport players to train under hypoxic conditions, both for repeating sprints (tunnel configuration) or small-side games (rectangular configuration).
Repeated sprint training in normobaric hypoxia
Authors: Galvin Harvey M , Cooke Karl , Sumners David P , Mileva Katya N , Bowtell Joanna L
Published: November 2013

Repeated sprint ability (RSA) is a critical success factor for intermittent sport performance. Repeated sprint training has been shown to improve RSA, we hypothesised that hypoxia would augment these training adaptations. Thirty male well-trained academy rugby union and rugby league players (18.4±1.5 years, 1.83±0.07 m, 88.1±8.9 kg) participated in this single-blind repeated sprint training study. Participants completed 12 sessions of repeated sprint training (10×6 s, 30 s recovery) over 4 weeks in either hypoxia (13% FiO2) or normoxia (21% FiO2). Pretraining and post-training, participants completed sports specific endurance and sprint field tests and a 10×6 s RSA test on a non-motorised treadmill while measuring speed, heart rate, capillary blood lactate, muscle and cerebral deoxygenation and respiratory measures. Yo-Yo Intermittent Recovery Level 1 test performance improved after RS training in both groups, but gains were significantly greater in the hypoxic (33±12%) than the normoxic group (14±10%, p<0.05). During the 10×6 s RS test there was a tendency for greater increases in oxygen consumption in the hypoxic group (hypoxic 6.9±9%, normoxic (−0.3±8.8%, p=0.06) and reductions in cerebral deoxygenation (% changes for both groups, p=0.09) after hypoxic than normoxic training. Twelve RS training sessions in hypoxia resulted in twofold greater improvements in capacity to perform repeated aerobic high intensity workout than an equivalent normoxic training. Performance gains are evident in the short term (4 weeks), a period similar to a preseason training block.
The impact of altitude on the sleep of young elite soccer players (ISA3600)
Authors: Sargent Charli , Schmidt Walter F , Aughey Robert J , Bourdon Pitre C , Soria Rudy , Claros Jesus C Jimenez , Garvican-Lewis Laura A , Buchheit Martin , Simpson Ben M , Hammond Kristal , Kley Marlen , Wachsmuth Nadine , Gore Christopher J , Roach Gregory D
Published: November 2013

Background

Altitude training is used by elite athletes to improve sports performance, but it may also disrupt sleep. The aim of this study was to examine the effects of 2 weeks at high altitude on the sleep of young elite athletes.

Methods

Participants (n=10) were members of the Australian under-17 soccer team on an 18-day (19-night) training camp in Bolivia, with six nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was monitored using polysomnography during a baseline night at 430 m and three nights at 3600 m (immediately after ascent, 1 week after ascent and 2 weeks after ascent). Data were analysed using effect size statistics.

Results

All results are reported as comparisons with baseline. Rapid eye movement (REM) sleep was likely lower immediately upon ascent to altitude, possibly lower after 1 week and similar after 2 weeks. On all three nights at altitude, hypopneas and desaturations were almost certainly higher; oxygen saturation was almost certainly lower; and central apnoeas, respiratory arousals and periodic breathing were very likely higher. The effects on REM sleep were common to all but one participant, but the effects on breathing were specific to only half the participants.

Conclusions

The immediate effects of terrestrial altitude of 3600 m are to reduce the amount of REM sleep obtained by young elite athletes, and to cause 50% of them to have impaired breathing during sleep. REM sleep returns to normal after 2 weeks at altitude, but impaired breathing does not improve.
Physical fitness, motor skill, and physical activity relationships in grade 4 to 6 children
Authors: Larouche Richard , Boyer Charles , Tremblay Mark Stephen , Longmuir Patricia
Published: November 2013

The present study sought to quantify the relationships among physical activity (PA), health-related fitness, and motor skill in children (grades 4 to 6), and to determine whether specific tests of fitness or motor skill are independently associated with objectively measured PA level. Four hundred and ninety-one students (56.4% female) wore a Digi-Walker pedometer for 7 consecutive days. Standardized protocols were used to assess health-related fitness (body mass index percentile, waist circumference, 20-m shuttle run, plank, handgrip, and trunk flexibility). Motor skill was evaluated using a validated obstacle course. Pearson correlations (with Holm adjustments for multiple comparisons) initially assessed associations among PA, health-related fitness, and motor skill. Multi-variable linear regression was used to determine which factors were significantly associated with daily step counts, while adjusting for gender, age, testing season, and socioeconomic status. Step counts were significantly correlated with predicted aerobic power (r = 0.30), obstacle course time (r = −0.27), obstacle course score (r = 0.20), plank isometric torso endurance (r = 0.16), and handgrip strength (r = 0.12), but not with waist circumference (r = −0.10), trunk flexibility (r = 0.10), or overweight status (ρ = −0.06). In the multi-variable model, predicted aerobic power, obstacle course time, testing season, gender, and the predicted aerobic power by gender interaction were significantly associated with step counts, explaining 16.4% of the variance. Specifically, the relationship between predicted aerobic power and step counts was stronger in girls. These findings suggest that aerobic fitness and motor skill are independently associated with children’s PA. Future longitudinal studies should evaluate whether interventions to enhance aerobic fitness and motor skill could enhance daily PA among children of this age.
Three-dimensional behaviour of a prototype radioactive waste repository in fractured granitic rock
Authors: Thomas Hywel R. , Vardon Philip J. , Cleall Peter J.
Published: November 2013

An investigation of the three-dimensional coupled thermohydromechanical behaviour of a prototype repository in fractured granitic rock is presented. The pre-placement behaviour of the repository is first considered, making use of a full three-dimensional simulation of the problem. An effective continuum approach, augmented with discrete features with a high hydraulic conductivity, is employed. The method adopted is found to be able to simulate accurately the highly anisotropic flow regime observed at the pre-placement phase. The major features of the full repository experiment under applied heating conditions were then successfully simulated. The range of buffer hydration rates, the thermal response of the repository, and the associated mechanical response were successfully simulated. Approaches to capture both the transient microstructural behaviour of the compacted bentonite (MX-80 type) and a MX-80 pellet material are incorporated. The repository behaviour was shown to be strongly influenced by complex coupled processes, including interactions between the system components. The adoption of a three-dimensional modelling approach proved to be essential to realistically simulate the behaviour of a repository incorporating anisotropic flow behaviour. Finally, potential impacts of the processes considered on performance of the barrier system and in safety assessment are considered.
Identification and comparison of the 3 early stages of resynthesis for the lichen Cladonia rangiferina
Authors: Athukorala Sarangi N.P. , Huebner Erwin , Piercey-Normore Michele D.
Published: November 2013

A lichen is an association between a biotrophic fungal partner and a green algal and (or) cyanobacterial partner, which may be considered a “controlled” parasitic interaction. While controlled parasitism implies benefit to both interacting partners, a parasitism that is not controlled implies that one partner benefits to the detriment of the other partner. The objective of this study was to compare morphological development of the interaction between Cladonia rangiferina with its compatible algal partner (Asterochloris glomerata/irregularis) and incompatible algae (Coccomyxa peltigerae and Chloroidium ellipsoideum) at 3 early resynthesis stages. The fungus was co-inoculated with each alga separately and the stages of development were compared using quantitative measures. The first 3 stages of development of the lichen thallus were identified in the compatible interaction as the “pre-contact” stage (1 day post co-inoculation (PCI)), “contact” stage (8 days PCI), and “growth together” stage (21 days PCI). Compatible interactions showed significantly shorter internode length, significantly more new lateral hyphal branches, significantly greater appressorial frequency, and no reduction in cell diameter of the algal cells, compared with incompatible interactions. At 21 days PCI, a parasitic interaction was observed between Cladonia rangiferina and Chloroidium ellipsoideum. These findings support the importance of recognition between compatible partners for successful lichenization. This study also revealed a strategy that may explain the success of this species in northern habitats. Identification of the resynthesis stages of Cladonia rangiferina is required before expression of the proteins involved in recognition and defense can be understood.
Strength training alters MCT1-protein expression and exercise-induced translocation in erythrocytes of men with non-insulin-dependent type-2 diabetes
Authors: Opitz David , Kreutz Thorsten , Lenzen Edward , Dillkofer Benedict , Wahl Patrick , Montiel-Garcia Gracia , Graf Christine , Bloch Wilhelm , Brixius Klara
Published: November 2013

We investigated the cellular distribution of lactate transporter (MCT1) and its chaperone CD147 (using immunohistochemistry and fluorescence-activated cell sorting) in the erythrocytes of men with non-insulin-dependent type-2 diabetes (NIDDM, n = 11, 61 ± 8 years of age) under acute exercise (ergometer cycling test, World Health Organisation scheme) performed before and after a 3-month strength training program. Cytosolic MCT1 distribution and membraneous CD147 density did not change after acute exercise (ergometer). After the 3-month strength training, MCT1-density was increased and the reaction of MCT1 (but not that of CD147) towards acute exercise (ergometer) was altered. MCT1 localisation was shifted from the centre to the cellular membrane. This resulted in a decrease in the immunohistochemically measured cytosolic MCT1-density. We conclude that strength training alters the acute exercise reaction of MCT1 but not that of CD147 in erythrocytes in patients with NIDDM. This reaction may contribute to long-term normalisation and stabilisation of the regulation of lactate plasma concentration in NIDDM.
ELECTRONIC TRANSPORT PROPERTIES OF TRANSITION METAL (Cu, Fe) PHTHALOCYANINES CONNECTING TO V-SHAPED ZIGZAG GRAPHENE NANORIBBONS
Authors: CUI LILING , YANG BINGCHU , LI XINMEI , HE JUN , LONG MENGQIU
Published: November 2013

Using nonequlilibrium Green's functions in combination with the density-functional theory, we investigate the spin transport properties of molecular junction based on metal ( Cu , Fe ) phthalocyanines between V-shaped zigzag-edged graphene nanorribons. The results show that the electronic transport properties mainly depend on the center transition metal. The negative differential resistance behaviors and spin splitting phenomenon can be observed.
THE CHARACTERIZATION OF TOPOLOGICAL PROPERTIES IN QUANTUM MONTE CARLO SIMULATIONS OF THE KANE–MELE–HUBBARD MODEL
Authors: MENG ZI YANG , HUNG HSIANG-HSUAN , LANG THOMAS C.
Published: November 2013

Topological insulators present a bulk gap, but allow for dissipationless spin transport along the edges. These exotic states are characterized by the Z2 topological invariant and are protected by time-reversal symmetry. The Kane–Mele model is one model to realize this topological class in two dimensions, also called the quantum spin Hall state. In this brief review article, we provide a pedagogical introduction to the influence of correlation effects in the quantum spin Hall states, with special focus on the half-filled Kane–Mele–Hubbard model, solved by means of unbiased determinant quantum Monte Carlo (QMC) simulations. We explain the idea of identifying the topological insulator via π-flux insertion, the Z2 invariant and the associated behavior of the zero-frequency Green's function, as well as the spin Chern number in parameter-driven topological phase transitions. The examples considered are two descendants of the Kane–Mele–Hubbard model, the generalized and dimerized Kane–Mele–Hubbard model. From the Z2 index, spin Chern numbers and the Green's function behavior, one can observe that correlation effects induce shifts of the topological phase boundaries. Although the implementation of these topological quantities has been successfully employed in QMC simulations to describe the topological phase transition, we also point out their limitations as well as suggest possible future directions in using numerical methods to characterize topological properties of strongly correlated condensed matter systems.
INTEGRATED STACKED-SPIRAL RF INDUCTOR WITH NANOPOWDER MAGNETIC CORE
Authors: ZHANG JING , YANG CHEN , WANG XIN , REN TIAN-LING , WANG ALBERT , YANG YI , TIAN L.-L.
Published: November 2013

On-chip stacked-spiral radio-frequency (RF) inductor with vertical nanopowder-magnetic-core was proposed and implemented in standard 0.18 μm six-metal CMOS with a post-CMOS backend process module (i.e., CMOS+). To improve on the prior open-magnetic-circuit-loop structure and thus limited improvement at multi-GHz performance, the non-traditional concept shows vertical magnetic core forming a near closed magnetic loop. The ferrite nanoparticle-magnetic-core reduced magnetic loss to improve L-density to 9 GHz. Results show the proof-of-concept designs greatly increase the inductance, L, by up to 34% and the factor, Q, by 62% over a multi-GHz frequency range.
A LOW POWER PUSH–PUSH VCO USING MULTI-COUPLED LC TANKS
Authors: NAGARAJAN MAHALINGAM , MA KAIXUE , YEO KIAT SENG , LIM WEI MENG
Published: November 2013

A fully integrated push–push voltage controlled oscillator (VCO) working in K-band with a large tuning range and a low phase noise fabricated in a 0.18 μm SiGe BiCMOS technology is presented. Multi-coupled LC tanks are used to improve the tuning range, power consumption and phase noise. Digital tuning varactors are used to maintain a low VCO tuning sensitivity (K VCO ) and maximum frequency overlap. The VCO achieves a frequency tuning range (FTR) of 17% at 12 GHz, a phase noise of -106.62 dBc/Hz at 1 MHz offset and consumes 7 mW from 1.8 V supply.
EVOLUTIONARY SEARCH FOR OPTIMIZED LNA COMPONENTS GEOMETRY
Authors: FATHIANPOUR A. , SEYEDTABAII S.
Published: November 2013

In this paper, an optimized design procedure based on genetic algorithm (GA) for automatic synthesis of dual-band concurrent fully integrated low-noise amplifiers (LNA) targeted to 802.16d @ 3.5 GHz and 802.11b, g @ 2.4 GHz standards is discussed. The algorithm delivers the circuit elements geometry, rather than their values, and bias levels to secure the best level of LNA gain, input matching, output matching and power consumption. Working on the components geometry level aims at considering the elements parasitic effects. The basic cascode and a current reuse folded cascode LNA's are tried. GA as an optimization engine is programmed in MATLAB and performance evaluation in 0.18 μm RF CMOS TSMC technology is ceded to HSPICE. Results indicate that the automated scheme well computes the desired circuit in an acceptable time span; otherwise, it may be explored by either tremendous manual trial and error or astronomical cycles of an exhaustive search. This is not accomplished without imposing certain approximate search space constraints.
Challenges in the noninvasive detection of body composition using near-infrared spectroscopy
Authors: Chen Wenliang , Jia Hao , Li Chenli , Xu Kexin
Published: November 2013

Noninvasive detection of body composition plays a significant role in the improvement of life quality and reduction in complications of the patients, and the near-infrared (NIR) spectroscopy, with the advantages of painlessness and convenience, is considered as the most promising tool for the online noninvasive monitoring of body composition. However, quite different from other fields of online detection using NIR spectroscopy, such as food safety and environment monitoring, noninvasive detection of body composition demands higher precision of the instruments as well as more rigorousness of measurement conditions. Therefore, new challenges emerge when NIR spectroscopy is applied to the noninvasive detection of body composition, which, in this paper, are first concluded from the aspects of measurement methods, measurement conditions, instrument precision, multi-component influence, individual difference and novel weak-signal extraction method based on our previous research in the cutting-edge field of NIR noninvasive blood glucose detection. Moreover, novel ideas and approaches of our group to solve these problems are introduced, which may provide evidence for the future development of noninvasive blood glucose detection, and further contribute to the noninvasive detection of other body compositions using NIR spectroscopy.
Sparse reconstruction for fluorescence molecular tomography via a fast iterative algorithm
Authors: Yu Jingjing , Cheng Jingxing , Hou Yuqing , He Xiaowei
Published: November 2013

Fluorescence molecular tomography (FMT) is a fast-developing optical imaging modality that has great potential in early diagnosis of disease and drugs development. However, reconstruction algorithms have to address a highly ill-posed problem to fulfill 3D reconstruction in FMT. In this contribution, we propose an efficient iterative algorithm to solve the large-scale reconstruction problem, in which the sparsity of fluorescent targets is taken as useful a priori information in designing the reconstruction algorithm. In the implementation, a fast sparse approximation scheme combined with a stage-wise learning strategy enable the algorithm to deal with the ill-posed inverse problem at reduced computational costs. We validate the proposed fast iterative method with numerical simulation on a digital mouse model. Experimental results demonstrate that our method is robust for different finite element meshes and different Poisson noise levels.