The influence of nonlinearities on the symmetric hydrodynamic response of a 10,000 TEU Container ship

The prediction of wave-induced motions and loads is of great importance for the design of marine structures. Linear potential flow hydrodynamic models are already used in different parts of the ship design development and appraisal process. However, the industry demands for design innovation and the possibilities offered by modern technology imply the need to also understand the modelling assumptions and associated influences of nonlinear hydrodynamic actions on ship response. At first instance, this paper presents the taxonomy of different Fluid Structure Interaction (FSI) methods that may be used for the assessment of ship motions and loads. Consequently, it documents in a practical way the effects of weakly nonlinear hydrodynamics on the symmetric wave-induced responses for a 10,000TEU Container ship. It is shown that the weakly nonlinear FSI models may be useful for the prediction of symmetric wave-induced loads and responses of such ship not only in way of amidships but also at the extremities of the hull. It is concluded that validation of hydrodynamic radiation and diffraction forces and their respective influence on ship response should be especially considered for those cases where the variations of the hull wetted surface in time may be noticeable

Spectral super-resolution in metamaterial composites

We investigate the optical properties of periodic composites containing metamaterial inclusions in a normal material matrix. We consider the case where these inclusions have sharp corners, and following Hetherington and Thorpe, use analytic results to argue that it is then possible to deduce the shape of the corner (its included angle) by measurements of the absorptance of such composites when the scale size of the inclusions and period cell is much finer than the wavelength. These analytic arguments are supported by highly accurate numerical results for the effective permittivity function of such composites as a function of the permittivity ratio of inclusions to matrix. The results show that this function has a continuous spectral component with limits independent of the area fraction of inclusions, and with the same limits for both square and staggered square arrays.Comment: 17 pages, 6 figure

Comparison of airway measurements during influenza-induced tachypnea in infant and adult cotton rats

<p>Abstract</p> <p>Background</p> <p>Increased respiratory rate (tachypnea) is frequently observed as a clinical sign of influenza pneumonia in pediatric patients admitted to the hospital. We previously demonstrated that influenza infection of adult cotton rats (<it>Sigmodon hispidus</it>) also results in tachypnea and wanted to establish whether this clinical sign was observed in infected infant cotton rats. We hypothesized that age-dependent differences in lung mechanics result in differences in ventilatory characteristics following influenza infection.</p> <p>Methods</p> <p>Lung tidal volume, dynamic elastance, resistance, and pleural pressure were measured in a resistance and compliance system on mechanically-ventilated anesthestized young (14–28 day old) and adult (6–12 week old) cotton rats. Animals at the same age were infected with influenza virus, and breathing rates and other respiratory measurements were recorded using a whole body flow plethysmograph.</p> <p>Results</p> <p>Adult cotton rats had significantly greater tidal volume (TV), and lower resistance and elastance than young animals. To evaluate the impact of this increased lung capacity and stiffening on respiratory disease, young and adult animals were infected intra-nasally with influenza A/Wuhan/359/95. Both age groups had increased respiratory rate and enhanced pause (<it>Penh</it>) during infection, suggesting lower airway obstruction. However, in spite of significant tachypnea, the infant (unlike the adult) cotton rats maintained the same tidal volume, resulting in an increased minute volume. In addition, the parameters that contribute to <it>Penh </it>were different: while relaxation time between breaths and time of expiration was decreased in both age groups, a disproportionate increase in peak inspiratory and expiratory flow contributed to the increase in <it>Penh </it>in infant animals.</p> <p>Conclusion</p> <p>While respiratory rate is increased in both adult and infant influenza-infected cotton rats, the volume of air exchanged per minute (minute volume) is increased in the infant animals only. This is likely to be a consequence of greater lung elastance in the very young animals. This model replicates many respiratory features of humans and consequently may be a useful tool to investigate new strategies to treat respiratory disease in influenza-infected infants.</p

The African swine fever virus dynein-binding protein p54 induces infected cell apoptosis

AbstractA specific interaction of ASFV p54 protein with 8 kDa light chain cytoplasmic dynein (DLC8) has been previously characterized and this interaction is critical during virus internalization and transport to factory sites. During early phases of infection, the virus induces the initiation of apoptosis triggering activation of caspase-9 and -3. To analyze the role of the structural protein p54 in apoptosis, transient expression experiments of p54 in Vero cells were carried out which resulted in effector caspase-3 activation and apoptosis. Interestingly, p54 mutants, lacking the 13 aa dynein-binding motif lose caspase activation ability and pro-death function of p54. This is the first reported ASFV protein which induces apoptosis

Expression of Foot-and-Mouth Disease Virus Capsid Proteins in Silkworm-Baculovirus Expression System and Its Utilization as a Subunit Vaccine

Background: Foot-and-mouth disease (FMD) is a highly contagious disease of livestock that causes severe economic loss in susceptible cloven-hoofed animals. Although the traditional inactivated vaccine has been proved effective, it may lead to a new outbreak of FMD because of either incomplete inactivation of FMDV or the escape of live virus from vaccine production workshop. Thus, it is urgent to develop a novel FMDV vaccine that is safer, more effective and more economical than traditional vaccines. Methodology and Principal Findings: A recombinant silkworm baculovirus Bm-P12A3C which contained the intact P1-2A and 3C protease coding regions of FMDV Asia 1/HNK/CHA/05 was developed. Indirect immunofluorescence test and sandwich-ELISA were used to verify that Bm-P12A3C could express the target cassette. Expression products from silkworm were diluted to 30 folds and used as antigen to immunize cattle. Specific antibody was induced in all vaccinated animals. After challenge with virulent homologous virus, four of the five animals were completely protected, and clinical symptoms were alleviated and delayed in the remaining one. Furthermore, a PD50 (50 % bovine protective dose) test was performed to assess the bovine potency of the subunit vaccine. The result showed the subunit vaccine could achieve 6.34 PD50 per dose

Lung Volume, Breathing Pattern and Ventilation Inhomogeneity in Preterm and Term Infants

BACKGROUND: Morphological changes in preterm infants with bronchopulmonary dysplasia (BPD) have functional consequences on lung volume, ventilation inhomogeneity and respiratory mechanics. Although some studies have shown lower lung volumes and increased ventilation inhomogeneity in BPD infants, conflicting results exist possibly due to differences in sedation and measurement techniques. METHODOLOGY/PRINCIPAL FINDINGS: We studied 127 infants with BPD, 58 preterm infants without BPD and 239 healthy term-born infants, at a matched post-conceptional age of 44 weeks during quiet natural sleep according to ATS/ERS standards. Lung function parameters measured were functional residual capacity (FRC) and ventilation inhomogeneity by multiple breath washout as well as tidal breathing parameters. Preterm infants with BPD had only marginally lower FRC (21.4 mL/kg) than preterm infants without BPD (23.4 mL/kg) and term-born infants (22.6 mL/kg), though there was no trend with disease severity. They also showed higher respiratory rates and lower ratios of time to peak expiratory flow and expiratory time (t(PTEF)/t(E)) than healthy preterm and term controls. These changes were related to disease severity. No differences were found for ventilation inhomogeneity. CONCLUSIONS: Our results suggest that preterm infants with BPD have a high capacity to maintain functional lung volume during natural sleep. The alterations in breathing pattern with disease severity may reflect presence of adaptive mechanisms to cope with the disease process

Detection of a Fourth Orbivirus Non-Structural Protein

The genus Orbivirus includes both insect and tick-borne viruses. The orbivirus genome, composed of 10 segments of dsRNA, encodes 7 structural proteins (VP1–VP7) and 3 non-structural proteins (NS1–NS3). An open reading frame (ORF) that spans almost the entire length of genome segment-9 (Seg-9) encodes VP6 (the viral helicase). However, bioinformatic analysis recently identified an overlapping ORF (ORFX) in Seg-9. We show that ORFX encodes a new non-structural protein, identified here as NS4. Western blotting and confocal fluorescence microscopy, using antibodies raised against recombinant NS4 from Bluetongue virus (BTV, which is insect-borne), or Great Island virus (GIV, which is tick-borne), demonstrate that these proteins are synthesised in BTV or GIV infected mammalian cells, respectively. BTV NS4 is also expressed in Culicoides insect cells. NS4 forms aggregates throughout the cytoplasm as well as in the nucleus, consistent with identification of nuclear localisation signals within the NS4 sequence. Bioinformatic analyses indicate that NS4 contains coiled-coils, is related to proteins that bind nucleic acids, or are associated with membranes and shows similarities to nucleolar protein UTP20 (a processome subunit). Recombinant NS4 of GIV protects dsRNA from degradation by endoribonucleases of the RNAse III family, indicating that it interacts with dsRNA. However, BTV NS4, which is only half the putative size of the GIV NS4, did not protect dsRNA from RNAse III cleavage. NS4 of both GIV and BTV protect DNA from degradation by DNAse. NS4 was found to associate with lipid droplets in cells infected with BTV or GIV or transfected with a plasmid expressing NS4

Time domains of the hypoxic ventilatory response in ectothermic vertebrates

Over a decade has passed since Powell et al. (Respir Physiol 112:123–134, 1998) described and defined the time domains of the hypoxic ventilatory response (HVR) in adult mammals. These time domains, however, have yet to receive much attention in other vertebrate groups. The initial, acute HVR of fish, amphibians and reptiles serves to minimize the imbalance between oxygen supply and demand. If the hypoxia is sustained, a suite of secondary adjustments occur giving rise to a more long-term balance (acclimatization) that allows the behaviors of normal life. These secondary responses can change over time as a function of the nature of the stimulus (the pattern and intensity of the hypoxic exposure). To add to the complexity of this process, hypoxia can also lead to metabolic suppression (the hypoxic metabolic response) and the magnitude of this is also time dependent. Unlike the original review of Powell et al. (Respir Physiol 112:123–134, 1998) that only considered the HVR in adult animals, we also consider relevant developmental time points where information is available. Finally, in amphibians and reptiles with incompletely divided hearts the magnitude of the ventilatory response will be modulated by hypoxia-induced changes in intra-cardiac shunting that also improve the match between O2 supply and demand, and these too change in a time-dependent fashion. While the current literature on this topic is reviewed here, it is noted that this area has received little attention. We attempt to redefine time domains in a more ‘holistic’ fashion that better accommodates research on ectotherms. If we are to distinguish between the genetic, developmental and environmental influences underlying the various ventilatory responses to hypoxia, however, we must design future experiments with time domains in mind

In Search of HPA Axis Dysregulation in Child and Adolescent Depression

Dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis in adults with major depressive disorder is among the most consistent and robust biological findings in psychiatry. Given the importance of the adolescent transition to the development and recurrence of depressive phenomena over the lifespan, it is important to have an integrative perspective on research investigating the various components of HPA axis functioning among depressed young people. The present narrative review synthesizes evidence from the following five categories of studies conducted with children and adolescents: (1) those examining the HPA system’s response to the dexamethasone suppression test (DST); (2) those assessing basal HPA axis functioning; (3) those administering corticotropin-releasing hormone (CRH) challenge; (4) those incorporating psychological probes of the HPA axis; and (5) those examining HPA axis functioning in children of depressed mothers. Evidence is generally consistent with models of developmental psychopathology that hypothesize that atypical HPA axis functioning precedes the emergence of clinical levels of depression and that the HPA axis becomes increasingly dysregulated from child to adult manifestations of depression. Multidisciplinary approaches and longitudinal research designs that extend across development are needed to more clearly and usefully elucidate the role of the HPA axis in depression