Critical energies for SSB and DSB induction in plasmid DNA by low-energy photons: action spectra for strand-break induction in plasmid DNA irradiated in vacuum

Purpose: To measure action spectra for the induction of single- strand breaks (SSB) and double-strand breaks (DSB) in plasmid DNA by low-energy photons and provide estimates for the energy dependence of strand-break formation important for track-structure simulations of DNA damage.

INCIDENCE AND CLINICAL IMPORTANCE OF PERIOPERATIVE HISTAMINE-RELEASE - RANDOMIZED STUDY OF VOLUME LOADING AND ANTIHISTAMINES AFTER INDUCTION OF ANESTHESIA

Although histamine release is recognised as a common event during anaesthesia and surgery, few clinicians judge the resultant cardiorespiratory disturbances serious enough to warrant prophylaxis with antihistamines. We have assessed the incidence and importance of histamine release in a randomised 2 x 2 factorial study.

Heating modes in capacitively coupled RF plasmas observed with emission spectroscopy

It is demonstrated that spatio-temporally resolved emission studies of a capacitively coupled gaseous electronics conference reference cell discharge can be used to determine changes in the heating mechanisms in such discharges.

Evaluation of induction of porcine dermatitis and nephropathy syndrome in gnotobiotic pigs with negative results for porcine circovirus type 2

Objective-To determine whether porcine dermatitis and nephropathy syndrome (PDNS) could be experimentally induced in gnotobiotic swine.

An ESPRIT-SAA-Based Detection Method for Broken Rotor Bar Fault in Induction Motors

This paper presents a novel detection method for broken rotor bar fault (BRB) in induction motors based on Estimation of Signal Parameters via Rotational Invariance Technique (ESPRIT) and Simulated Annealing Algorithm (SAA). The performance of ESPRIT is tested with simulated stator current signal of an induction motor with BRB. It shows that even with a short-time measurement data, the technique is capable of correctly identifying the frequencies of the BRB characteristic components but with a low accuracy on the amplitudes and initial phases of those components. SAA is then used to determine their amplitudes and initial phases and shows satisfactory results. Finally, experiments on a 3kW, 380V, 50Hz induction motor are conducted to demonstrate the effectiveness of the ESPRIT-SAA-based method in detecting BRB with short-time measurement data. It proves that the proposed method is a promising choice for BRB detection in induction motors operating with small slip and fluctuant load.

Scattering theory of cooling and heating in optomechanical systems

We present a one-dimensional scattering theory which enables us to describe a wealth of effects arising from the coupling of the motional degree of freedom of scatterers to the electromagnetic field. Multiple scattering to all orders is taken into account. The theory is applied to describe the scheme of a Fabry-Perot resonator with one of its mirrors moving. The friction force, as well as the diffusion, acting on the moving mirror is derived. In the limit of a small reflection coefficient, the same model provides for the description of the mechanical effect of light on an atom moving in front of a mirror.

Particle simulation study of electron heating by counter-streaming ion beams ahead of supernova remnant shocks

The growth and saturation of Buneman-type instabilities is examined with a particle-in-cell (PIC) simulation for parameters that are representative for the foreshock region of fast supernova remnant shocks. A dense ion beam and the electrons correspond to the upstream plasma and a fast ion beam to the shock-reflected ions. The purpose of the 2D simulation is to identify the nonlinear saturation mechanisms, the electron heating and potential secondary instabilities that arise from anisotropic electron heating and result in the growth of magnetic fields. We confirm that the instabilities between both ion beams and the electrons saturate by the formation of phase space holes by the beam-aligned modes. The slower oblique modes accelerate some electrons, but they cannot heat up the electrons significantly before they are trapped by the faster beam-aligned modes. Two circular electron velocity distributions develop, which are centred around the velocity of each ion beam. They develop due to the scattering of the electrons by the electrostatic wave potentials. The growth of magnetic fields is observed, but their amplitude remains low.

High-affinity NO(3-)-H+ cotransport in the fungus Neurospora:induction and control by pH and membrane voltage

High-affinity nitrate transport was examined in intact hyphae of Neurospora crassa using electrophysiological recordings to characterize the response of the plasma membrane to NO3- challenge and to quantify transport activity. The NO3(-)-associated membrane current was determined using a three electrode voltage clamp to bring membrane voltage under experimental control and to compensate for current dissipation along the longitudinal cell axis. Nitrate transport was evident in hyphae transferred to NO3(-)-free, N-limited medium for 15 hr, and in hyphae grown in the absence of a nitrogen source after a single 2-min exposure to 100 microM NO3-. In the latter, induction showed a latency of 40-80 min and rose in scalar fashion with full transport activity measurable approx. 100 min after first exposure to NO3-; it was marked by the appearance of a pronounced sensitivity of membrane voltage to extracellular NO3- additions which, after induction, resulted in reversible membrane depolarizations of (+)54-85 mV in the presence of 50 microM NO3-; and it was suppressed when NH4+ was present during the first, inductive exposure to NO3-. Voltage clamp measurements carried out immediately before and following NO3- additions showed that the NO3(-)-evoked depolarizations were the consequence of an inward-directed current that appeared in parallel with the depolarizations across the entire range of accessible voltages (-400 to +100 mV). Measurements of NO3- uptake using NO3(-)-selective macroelectrodes indicated a charge stoichiometry for NO3- transport of 1(+):1(NO3-) with common K(m) and Jmax values around 25 microM and 75 pmol NO3- cm-2sec-1, respectively, and combined measurements of pHo and [NO3-]o showed a net uptake of approx. 1 H+ with each NO3- anion. Analysis of the NO3- current demonstrated a pronounced voltage sensitivity within the normal physiological range between -300 and -100 mV as well as interactions between the kinetic parameters of membrane voltage, pHo and [NO3-]o. Increasing the bathing pH from 5.5 to 8.0 reduced the current and the associated membrane depolarizations 2- to 4-fold. At a constant pHo of 6.1, driving the membrane voltage from -350 to -150 mV resulted in an approx. 3-fold reduction in the maximum current and a 5-fold rise in the apparent affinity for NO3-. By contrast, the same depolarization effected an approx. 20% fall in the K(m) for transport as a function in [H+]o. These, and additional results are consistent with a charge-coupling stoichiometry of 2(H+) per NO3- anion transported across the membrane, and implicate a carrier cycle in which NO3- binding is kinetically adjacent to the rate-limiting step of membrane charge transit. The data concur with previous studies demonstrating a pronounced voltage-dependence to high-affinity NO3- transport system in Arabidopsis, and underline the importance of voltage as a kinetic factor controlling NO3- transport; finally, they distinguish metabolite repression of NO3- transport induction from its sensitivity to metabolic blockade and competition with the uptake of other substrates that draw on membrane voltage as a kinetic substrate.

Wild-type Measles Virus Infection Upregulates Poliovirus Receptor-Related 4 and Causes Apoptosis in Brain Endothelial Cells by Induction of Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand

Small numbers of brain endothelial cells (BECs) are infected in children with neurologic complications of measles virus (MV) infection. This may provide a mechanism for virus entry into the central nervous system, but the mechanisms are unclear. Both in vitro culture systems and animal models are required to elucidate events in the endothelium. We compared the ability of wild-type (WT), vaccine, and rodent-adapted MV strains to infect, replicate, and induce apoptosis in human and murine brain endothelial cells (HBECs and MBECs, respectively). Mice also were infected intracerebrally. All MV stains productively infected HBECs and induced the MV receptor PVRL4. Efficient WT MV production also occurred in MBECs. Extensive monolayer destruction associated with activated caspase 3 staining was observed in HBECs and MBECs, most markedly with WT MV. Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL), but not Fas ligand, was induced by MV infection. Treatment of MBECs with supernatants from MV-infected MBEC cultures with an anti-TRAIL antibody blocked caspase 3 expression and monolayer destruction. TRAIL was also expressed in the endothelium and other cell types in infected murine brains. This is the first demonstration that infection of low numbers of BECs with WT MV allows efficient virus production, induction of TRAIL, and subsequent widespread apoptosis.

Analysis of the networks controlling the antimicrobial-peptide-dependent induction of Klebsiella pneumoniae virulence factors

Antimicrobial peptides (APs) impose a threat to the survival of pathogens, and it is reasonable to postulate that bacteria have developed strategies to counteract them. Polymyxins are becoming the last resort to treat infections caused by multidrug-resistant Gram-negative bacteria and, similar to APs, they interact with the anionic lipopolysaccharide. Given that polymyxins and APs share the initial target, it is possible that bacterial defense mechanisms against polymyxins will be also effective against host APs. We sought to determine whether exposure to polymyxin will increase Klebsiella pneumoniae resistance to host APs. Indeed, exposure of K. pneumoniae to polymyxin induces cross-resistance not only to polymyxin itself but also to APs present in the airways. Polymyxin treatment upregulates the expression of the capsule polysaccharide operon and the loci required to modify the lipid A with aminoarabinose and palmitate with a concomitant increase in capsule and lipid A species containing such modifications. Moreover, these surface changes contribute to APs resistance and also to polymyxin-induced cross-resistance to APs. Bacterial loads of lipid A mutants in trachea and lungs of intranasally infected mice were lower than those of wild-type strain. PhoPQ, PmrAB, and the Rcs system govern polymyxin-induced transcriptional changes, and there is a cross talk between PhoPQ and the Rcs system. Our findings support the notion that Klebsiella activates a defense program against APs that is controlled by three signaling systems. Therapeutic strategies directed to prevent the activation of this program could be a new approach worth exploring to facilitate the clearance of the pathogen from the airways.

Nonlinear phenomena in multiferroic nanocapacitors:joule heating and electromechanical effects

We demonstrate an approach for probing nonlinear electromechanical responses in BiFeO(3) thin film nanocapacitors using half-harmonic band excitation piezoresponse force microscopy (PFM). Nonlinear PFM images of nanocapacitor arrays show clearly visible clusters of capacitors associated with variations of local leakage current through the BiFeO(3) film. Strain spectroscopy measurements and finite element modeling point to significance of the Joule heating and show that the thermal effects caused by the Joule heating can provide nontrivial contributions to the nonlinear electromechanical responses in ferroic nanostructures. This approach can be further extended to unambiguous mapping of electrostatic signal contributions to PFM and related techniques.