Correlation Functions of the Quantum Sine-Gordon Model in and out of Equilibrium.

Complete information on the equilibrium behavior and dynamics of quantum field theory (QFT) is provided by multipoint correlation functions. However, their theoretical calculation is a challenging problem, even for exactly solvable models. This has recently become an experimentally relevant problem, due to progress in cold-atom experiments simulating QFT models and directly measuring higher order correlations. Here we compute correlation functions of the quantum sine-Gordon model, a prototype integrable model of central interest from both theoretical and experimental points of view. Building upon the so-called truncated conformal space approach, we numerically construct higher order correlations in a system of finite size in various physical states of experimental relevance, both in and out of equilibrium. We measure deviations from Gaussianity due to the presence of interaction and analyze their dependence on temperature, explaining the experimentally observed crossover between Gaussian and non-Gaussian regimes. We find that correlations of excited states are markedly different from the thermal case, which can be explained by the integrability of the system. We also study dynamics after a quench, observing the effects of the interaction on the time evolution of correlation functions, their spatial dependence, and their non-Gaussianity as measured by the kurtosis.

Food and water intake, body temperature and metabolic consequences of interleukin-1ß microinjection into the cingulate cortex of the rat.

In order to elucidate whether cytokine mechanisms of the cingulate cortex (cctx) are important in the central regulation of homeostasis, in the present study, feeding-metabolic effects of direct bilateral microinjection of interleukin-1ß (IL-1ß) into the cctx of the rat have been investigated. Short- (2h), medium (12h) and long-term (24h) food and water intakes and body temperature were measured after the intracerebral administration of this primary cytokine or vehicle solution, with or without paracetamol pretreatment. The effect of IL-1ß on the blood glucose level of animals was examined in glucose tolerance test (GTT), and concentrations of relevant plasma metabolites (total cholesterol, HDL, LDH, triglycerides, uric acid) were additionally also determined following the above microinjections. In contrast to causing no major alteration in the food and water intakes, the cytokine treatment evoked significant increase in the body temperature of the rats. Prostaglandin-mediated mechanisms were shown to have important role in the mode of this action of IL-1ß, since paracetamol pretreatment partially prevented the development of the above mentioned hyperthermia. In the GTT, no considerable difference was observed between the blood glucose levels of the cytokine treated and control animals. Following IL-1ß microinjection, however, significant decrease of HDL and total cholesterol was found. Our present findings indicate that elucidating the IL-1ß mediated homeostatic control mechanisms in the cingulate cortex may lead to the better understanding not only the regulatory entities of the healthy organism but also those found in obesity, diabetes mellitus and other worldwide rapidly spreading feeding-metabolic disorders.

Impaired glucose tolerance after streptozotocin microinjection into the mediodorsal prefrontal cortex of the rat.

The mediodorsal prefrontal cortex (mdPFC) is a key structure of the central glucose-monitoring (GM) neural network. Previous studies indicate that intracerebral streptozotocin (STZ) microinjection-induced destruction of local chemosensory neurons results in feeding and metabolic alterations. The present experiments aimed to examine whether STZ microinjection into the mdPFC causes metabolic deficits. To do so, glucose tolerance test (GTT) and measurements of plasma metabolites were performed in STZ-treated or control rats. Intraperitoneal D-glucose load was delivered 20 min or 4 weeks following the intracerebral microinjection of STZ or saline (acute or subacute GTT, respectively). The STZ-treated rats displayed acute glucose intolerance: at the 120th min of the test, blood glucose level of these rats was significantly higher than that of the ones in the control group. When determining the plasma level of various metabolites, 30 min following the intracerebral STZ or saline microinjection, the triglyceride concentration of the STZ-treated rats was found to be reduced compared with that of the control rats. The GM neurons of the mdPFC are suggested to be involved in the organization of complex metabolic processes by which these chemosensory cells contribute to adaptive control mechanisms of the maintenance of homeostasis.

Correlations after quantum quenches in the XXZ spin chain: failure of the generalized Gibbs ensemble.

We study the nonequilibrium time evolution of the spin-1/2 anisotropic Heisenberg (XXZ) spin chain, with a choice of dimer product and Néel states as initial states. We investigate numerically various short-ranged spin correlators in the long-time limit and find that they deviate significantly from predictions based on the generalized Gibbs ensemble (GGE) hypotheses. By computing the asymptotic spin correlators within the recently proposed quench-action formalism [Phys. Rev. Lett. 110, 257203 (2013)], however, we find excellent agreement with the numerical data. We, therefore, conclude that the GGE cannot give a complete description even of local observables, while the quench-action formalism correctly captures the steady state in this case.

Microbeam radiation therapy: a Monte Carlo study of the influence of the source, multislit collimator, and beam divergence on microbeams.

Microbeam radiation therapy (MRT) is a new oncology method currently under development for the treatment of inoperable pediatric brain tumors. Monte Carlo simulation, or the computational study of radiation transport in matter, is often used in radiotherapy to theoretically estimate the dose required for treatment. However, its potential use in MRT dose planning systems is currently hindered by the significant discrepancies that have been observed between measured and theoretical dose and the PVDR (peak to valley dose ratio). The need to resolve these discrepancies is driven by the desirability of making MRT available to humans in the next few years. This article aims to resolve some of the discrepancies by examining the simplifications adopted in previous MRT Monte Carlo studies, such as the common practice of commencing microbeam transport on the surface of the target which neglects the influence of the distributed synchrotron source, multislit collimator, and the beam divergence between them. This article uses PENELOPE Monte Carlo simulation to investigate the influence of these beamline components upstream of the target on the lateral dose profiles and PVDRs of an array of 25 microbeams. It also compares the dose profiles and PVDRs of a microbeam array produced from a single simulation (full array) to those produced from the superposition of a single microbeam profile (sup array). The effect of modeling the distributed source and the beam divergence was an increase in the absorbed dose in the penumbral and valley regions of the microbeam profiles. Inclusion of the multislit collimator resulted in differences of up to 5 microm in the FWHM of microbeam profiles across the array, which led to minor variations in the corresponding PVDR yields.

Effect of transverse magnetic fields on dose distribution and RBE of photon beams: comparing PENELOPE and EGS4 Monte Carlo codes.

The application of a strong transverse magnetic field to a volume undergoing irradiation by a photon beam can produce localized regions of dose enhancement and dose reduction. This study uses the PENELOPE Monte Carlo code to investigate the effect of a slice of uniform transverse magnetic field on a photon beam using different magnetic field strengths and photon beam energies. The maximum and minimum dose yields obtained in the regions of dose enhancement and dose reduction are compared to those obtained with the EGS4 Monte Carlo code in a study by Li et al (2001), who investigated the effect of a slice of uniform transverse magnetic field (1 to 20 Tesla) applied to high-energy photon beams. PENELOPE simulations yielded maximum dose enhancements and dose reductions as much as 111% and 77%, respectively, where most results were within 6% of the EGS4 result. Further PENELOPE simulations were performed with the Sheikh-Bagheri and Rogers (2002) input spectra for 6, 10 and 15 MV photon beams, yielding results within 4% of those obtained with the Mohan et al (1985) spectra. Small discrepancies between a few of the EGS4 and PENELOPE results prompted an investigation into the influence of the PENELOPE elastic scattering parameters C(1) and C(2) and low-energy electron and photon transport cut-offs. Repeating the simulations with smaller scoring bins improved the resolution of the regions of dose enhancement and dose reduction, especially near the magnetic field boundaries where the dose deposition can abruptly increase or decrease. This study also investigates the effect of a magnetic field on the low-energy electron spectrum that may correspond to a change in the radiobiological effectiveness (RBE). Simulations show that the increase in dose is achieved predominantly through the lower energy electron population.

Miniature semiconductor detectors for in vivo dosimetry.

Silicon mini-semiconductor detectors are found in wide applications for in vivo personal dosimetry and dosimetry and microdosimetry of different radiation oncology modalities. These applications are based on integral and spectroscopy modes of metal oxide semiconductor field effect transistor and silicon p-n junction detectors. The advantages and limitations of each are discussed.

Ex vivo development of a composite human oral mucosal equivalent.

PURPOSE: The aim of this study was the ex vivo development of a composite oral mucosal equivalent composed of a continuous stratified layer of human oral keratinocytes grown on a cadaveric human dermal matrix in a defined medium without a feeder layer. MATERIALS AND METHODS: Enzymatically dissociated human oral keratinocytes from keratinized oral mucosa were cultured, submerged in a serum-free, low-calcium (0.15 mmol/L) supplemented medium, and expanded through several passages. Once a sufficient population of keratinocytes was reached, they were seeded on 1-cm2 pieces of AlloDerm (LifeCell Co, Woodlands, TX), an acellular nonimmunogenic cadaveric human dermis, at cell densities of 2.5 X 10(4), 5.0 X 10(4), 1.25 X 10(5), or 2.5 X 10(5). The oral keratinocyte-AlloDerm composites were cultured while submerged in a high-calcium (1.8 mmol/L) medium for 4 days. After 4 days, the composites were raised to an air-liquid interface. Samples of the composites were taken for histologic examination at 4, 11, and 18 days postseeding of the keratinocytes on the AlloDerm. RESULTS: At day 4, only the seeded cell density of 2.5 X 10(5) cells/cm2 formed a continuous monolayer on the AlloDerm. At day 11, a continuous stratified epithelium was seen, and at day 18 a well-differentiated, confluent parakeratotic epithelial layer was developed at cell densities of 5.0 X 10(4), 1.25 X 10(5), and 2.5 X 10(5)cells/cm2. CONCLUSION: With the method used, it was possible to successfully develop an ex vivo composite oral mucosal equivalent that consisted of a stratified epidermis on a dermal matrix.

Economic evaluation of 2 treatments for pediatric femoral shaft fractures.

The purpose of this study was to assess the relative health system costs of early hip spica cast immobilization and external fixation for pediatric femoral shaft fractures. A cost analysis was performed from the viewpoint of the study hospital and physicians using protocols based on current practice. Cost estimates were based on patient and financial information from April 1, 1993, to January 31, 1994, including the fully allocated inpatient and outpatient costs. A sensitivity analysis was conducted to analyze the effect of complications on costs. Total estimated costs (in 1994 Canadian dollars, $1.00 = $0.75 US) of uncomplicated external fixation and hip spica treatments were $7626.30 and $5970.11, respectively. Fifty percent of this difference was attributable to longer inpatient stays for the external fixation treatment. The remaining difference was because of the cost of the fixator, additional operating room staff time costs, and additional professional and technical fees. Total expected costs of treatment complicated by loss of reduction, pin tract infection, and return to the operating room were $7716.01 and $6128.44 for the external fixation and hip spica treatment options, respectively. For the range of complication probabilities considered, expected total costs were always greater with the external fixation option than with the hip spica treatment.

Obstetric anaesthesia in Hungary.

A nation-wide survey of pain relief in childbirth in Hungary was carried out in 1993. Information was provided on 104 137 deliveries in 98 units. The frequencies of different methods of pain relief for vaginal delivery were as follows: systemic opiates in 7387 cases (8.3%), epidural analgesia in 4611 cases (5.2%) and inhalational analgesia (nitrous oxide) in 4470 cases (5%). Epidural analgesia was available in 36 units (36.7%). For 71 744 vaginal deliveries (80.5%) no pain relief was provided at all. For caesarean section (n = 13240) the rate of spinal or epidural anaesthesia was 36.7%. It was concluded that despite an increasing rate of pain relief in labour elsewhere, the numbers of epidurals are still rather low in Hungary.

[Gynecologic and obstetric anesthesia in Hungary 1993]. / A szülészeti és nögyógyászati anesztézia helyzete Magyarországon 1993-ban.

Authors publish findings of a nationwide survey of pain relief in childbirth in Hungary carried out during the year of 1993. Informations were provided on 104,137 deliveries in 98 units. At 71,744 vaginal deliveries (81%) not any types of pain relief were used. The frequency ot different types of pain reliefs at vaginal deliveries were as follows: systemic opioids at 7387 cases (8.3%), epidural analgesia at 4611 cases (5.2%) and inhalational analgesia (nitrous oxide) at 4470 cases (5.0%). The availability of epidural analgesia at 62 units was absent. The rate of spinal--epidural analgesia at Cesarean sections was 37% (n = 13,240). At gynaecological laparotomies (n = 18,219) the rate of general anaesthesia was 98%, this rate at vaginal hysterectomies was 56.8% (n = 1568). Authors conclude that the rate of pain relief in labour in Hungary is unreasonably low. The reason of it is the lack of anaesthetists and also the traditional view, which does not recognize the importance of the pain relief in labour.