Far-field representation for the vertical force on a floating structure

This article is closed access.Equations are derived that relate the vertical hydrodynamic force on two- and threedimensional structures that are floating in a fluid of infinite depth to the far-field dipole coefficient in the velocity potential. By an application of Green’s theorem to the radiation or scattering potential and a suitable test potential, the heave added mass, the heave damping and the vertical exciting force are shown to be expressible in terms of the dipole coefficient in the relevant potential. The results add to the known reciprocity relations, which relate quantities such as the damping and the exciting force to the amplitude of the far-field radiated wave. The expressions are valid at all frequencies, and their high- and low-frequency asymptotics are investigated

Перспективи розвитку медичної освіти студентів-іноземців під час вивчення загальної хірургії та підвищення ефективності засвоєння базових теоретичних знань і практичних навичок

Перспективи розвитку медичної освіти студентів-іноземців під час вивчення загальної хірургії та підвищення ефективності засвоєння базових теоретичних знань і практичних навичо

Bacterial virulence factor inhibits caspase-4/11 activation in intestinal epithelial cells

The human pathogen enteropathogenic Escherichia coli (EPEC), as well as the mouse pathogen Citrobacter rodentium, colonize the gut mucosa via attaching and effacing lesion formation and cause diarrheal diseases. EPEC and C. rodentium type III secretion system (T3SS) effectors repress innate immune responses and infiltration of immune cells. Inflammatory caspases such as caspase-1 and caspase-4/11 are crucial mediators of host defense and inflammation in the gut via their ability to process cytokines such as interleukin (IL)-1β and IL-18. Here we report that the effector NleF binds the catalytic domain of caspase-4 and inhibits its proteolytic activity. Following infection of intestinal epithelial cells (IECs) EPEC inhibited caspase-4 and IL-18 processing in an NleF-dependent manner. Depletion of caspase-4 in IECs prevented the secretion of mature IL-18 in response to infection with EPECΔnleF. NleF-dependent inhibition of caspase-11 in colons of mice prevented IL-18 secretion and neutrophil influx at early stages of C. rodentium infection. Neither wild-type C. rodentium nor C. rodentiumΔnleF triggered neutrophil infiltration or IL-18 secretion in Cas11 or Casp1/11-deficient mice. Thus, IECs have a key role in modulating early innate immune responses in the gut via a caspase-4/11—IL-18 axis, which is targeted by virulence factors encoded by enteric pathogens

DOR’s method prevents functional disorder after laparoscopic hernia hyatoplastic of patients with esophageal diaphragm hernia

Проблема оптимальной хирургической пластики дефекта пищеводного отверстия диафрагмы до сих пор остается весьма актуальной. В последнее время некоторые хирурги применяют операцию, предложенную J. Dor, которая предусматривает лапароскопическую мобилизацию дистального участка пищевода, заднюю и переднюю крурорафию и переднюю фундопликацию. В течение последних 3 лет было выполнено 27 операций по методике Dor. Согласно нашим результатам лечения, ни один из пациентов не жаловался на какие-либо проявления дисфагии и gas bloating syndrome. Считаем преимуществами методики Dor простоту технического исполнения, уменьшение времени и травматичности вмешательства, физиологичное восстановление угла His и абдоминальной позиции дистального отдела пищевода, что позволяет избежать тяжелых функциональных расстройств в послеоперационном периоде.The problem of optimal surgical plastic of hiatal defect is still very relevant. Patients undergoing these interventions suffer from varying degrees of severity of dysphagia and inability to cope independently with excess air in the stomach (gas bloating syndrome), which noted 80% of patients because the artificially created cuff is the absolute valve. Recently, a number of surgeons have applied the operation proposed by J. Dor, which provides laparoscopic mobilization of the distal portion of the esophagus, front and rear cruroraphy and front fundoplication. According to our results of treatment, none of the patients complained of any dysphagia and gas bloating syndrome. We believe the benefits of Dor techniques simplicity, reducing the time and trauma intervention, physiological recovery angle of His and abdominal position of the distal part of esophagus, thereby avoiding severe functional disorders in the postoperative period. In our view, anterior fundoplication for Dor is more physiological and avoids of severe functional disorders in the postoperative period

Bacterial virulence factor inhibits caspase-4/11 activation in intestinal epithelial cells.

The human pathogen enteropathogenic Escherichia coli (EPEC), as well as the mouse pathogen Citrobacter rodentium, colonize the gut mucosa via attaching and effacing lesion formation and cause diarrheal diseases. EPEC and C. rodentium type III secretion system (T3SS) effectors repress innate immune responses and infiltration of immune cells. Inflammatory caspases such as caspase-1 and caspase-4/11 are crucial mediators of host defense and inflammation in the gut via their ability to process cytokines such as interleukin (IL)-1β and IL-18. Here we report that the effector NleF binds the catalytic domain of caspase-4 and inhibits its proteolytic activity. Following infection of intestinal epithelial cells (IECs) EPEC inhibited caspase-4 and IL-18 processing in an NleF-dependent manner. Depletion of caspase-4 in IECs prevented the secretion of mature IL-18 in response to infection with EPECΔnleF. NleF-dependent inhibition of caspase-11 in colons of mice prevented IL-18 secretion and neutrophil influx at early stages of C. rodentium infection. Neither wild-type C. rodentium nor C. rodentiumΔnleF triggered neutrophil infiltration or IL-18 secretion in Cas11 or Casp1/11-deficient mice. Thus, IECs have a key role in modulating early innate immune responses in the gut via a caspase-4/11-IL-18 axis, which is targeted by virulence factors encoded by enteric pathogens

The Q2Q^2-dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron

The Gerasimov-Drell-Hearn (GDH) sum rule connects the anomalous contribution to the magnetic moment of the target nucleus with an energy-weighted integral of the difference of the helicity-dependent photoabsorption cross sections. The data collected by HERMES with a deuterium target are presented together with a re-analysis of previous measurements on the proton. This provides a measurement of the generalised GDH integral covering simultaneously the nucleon-resonance and the deep inelastic scattering regions. The contribution of the nucleon-resonance region is seen to decrease rapidly with increasing $Q^2$. The DIS contribution is sizeable over the full measured range, even down to the lowest measured $Q^2$. As expected, at higher $Q^2$ the data are found to be in agreement with previous measurements of the first moment of $g_1$. From data on the deuteron and proton, the GDH integral for the neutron has been derived and the proton--neutron difference evaluated. This difference is found to satisfy the fundamental Bjorken sum rule at $Q^2 = 5$ GeV$^2$.Comment: 12 pages, 10 figure

Evidence for Quark-Hadron Duality in the Proton Spin Asymmetry A1A_1

Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry $A_1$. Longitudinally polarised positrons were scattered off a longitudinally polarised hydrogen target for values of $Q^2$ between 1.2 and 12 GeV$^2$ and values of $W^2$ between 1 and 4 GeV$^2$. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable $x$. This finding implies that the description of $A_1$ in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of $Q^2$ above 1.6 GeV$^2$.Comment: 5 pages, 1 eps figure, table added, new references added, in print in Phys. Rev. Let