234 research outputs found

    Influence of applying different units of measurement on reporting antimicrobial consumption data for pig farms

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    Background: Antimicrobial use in livestock is one of the factors contributing to selection and spread of resistant microorganisms in the environment. National ve

    Phosphorescence-Fluorescence ratio imaging for monitoring the oxygen status during photodynamic therapy

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    The effectiveness of photodynamic therapy is strongly dependent on the availabilty of oxygen. In the present paper we show that the ratio between photosensitiser phosphorescence and fluorescence is a parameter that can be used to monitor the competition between singlet oxygen production and other processes quenching the photosensitiser triplet state. We present a theoretical basis for the validity of this approach and a series of in vitro imaging experiments

    Assessing the microcirculation with handheld vital microscopy in critically ill neonates and children: Evolution of the technique and its potential for critical care

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    Assuring adequate tissue oxygenation in the critically ill, but still developing child is challenging. Conventional hemodynamic monitoring techniques fall short in assessing tissue oxygenation as these are directed at the macrocirculation and indirect surrogates of tissue oxygenation. The introduction of handheld vital microscopy (HVM) has allowed for the direct visualization of the microcirculation and with this has offered insight into tissue oxygenation on a microcirculatory level. Since its introduction, technical improvements have been made to HVM, to both hardware and software, and guidelines have been developed through expert consensus on image assessment and analysis. Using HVM, the microcirculation of the skin, the buccal mucosa, and the sublingual mucosa of healthy and (critically) ill neonates and children have been visualized and investigated. Yet, integration of HVM in hemodynamic monitoring has been limited due to technical shortcomings. Only superficial microcirculatory beds can be visualized, inter-observer and intra-observer variabilities are not accounted for and image analysis happens offline and is semi-automated and time-consuming. More importantly, patients need to be cooperative or fully sedated to prevent pressure and movement artifacts, which is often not the case in children. Despite these shortcomings, observational research with HVM in neonates and children has revealed the following: (1) age-related developmental changes in the microcirculation, (2) loss of hemodynamic coherence, i.e., microcirculatory disturbances in the presence of a normal macrocirculation and, (3) microcirculatory disturbances which were independently associated with increased mortality risk. Although these observations underline the importance of microcirculatory monitoring, several steps have to be taken before integration in the decision process during critical care can happen. These steps include technological innovations to ease the use of HVM in the pediatric age group, measuring additional functional parameters of microvascular blood flow and integrated automated analysis software. As a next step, reference values for microcirculatory parameters need to be established, while also accounting for developmental changes. Finally, studies on microcirculatory guided therapies are necessary to assess whether the integration of microcirculatory monitoring will actually improve patient outcome. Nevertheless, HVM remains a promising, noninvasive tool to help physicians assure tissue oxygenation in the critically ill child

    The Deformable Universe

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    The concept of smooth deformations of a Riemannian manifolds, recently evidenced by the solution of the Poincar\'e conjecture, is applied to Einstein's gravitational theory and in particular to the standard FLRW cosmology. We present a brief review of the deformation of Riemannian geometry, showing how such deformations can be derived from the Einstein-Hilbert dynamical principle. We show that such deformations of space-times of general relativity produce observable effects that can be measured by four-dimensional observers. In the case of the FLRW cosmology, one such observable effect is shown to be consistent with the accelerated expansion of the universe.Comment: 20 pages, LaTeX, 3 figure

    Non-Minimal Warm Inflation and Perturbations on the Warped DGP Brane with Modified Induced Gravity

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    We construct a warm inflation model with inflaton field non-minimally coupled to induced gravity on a warped DGP brane. We incorporate possible modification of the induced gravity on the brane in the spirit of f(R)f(R)-gravity. We study cosmological perturbations in this setup. In the case of two field inflation such as warm inflation, usually entropy perturbations are generated. While it is expected that in the case of one field inflation these perturbations to be removed, we show that even in the absence of the radiation field, entropy perturbations are generated in our setup due to non-minimal coupling and modification of the induced gravity.Comment: 29 pages, 7 figures, Accepted by Gen. Rel Gravi

    The sublingual microcirculation throughout neonatal and pediatric extracorporeal membrane oxygenation treatment: Is it altered by systemic extracorporeal support?

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    Background: Extracorporeal membrane oxygenation (ECMO) treatment alleviates systemic cardiorespiratory failure. However, it is unclear whether ECMO also improves microcirculatory function, as the microcirculation can be disturbed despite normal systemic hemodynamics. We therefore aimed to study the sublingual microcirculation (SMC) throughout neonatal and pediatric ECMO treatment. We hypothesized that the SMC improves after starting ECMO, that the SMC differs between venovenous (VV) and venoarterial (VA) ECMO, and that insufficient recovery of microcirculatory disturbances during ECMO predicts mortality. Methods: This single-center prospective longitudinal observational study included 34 consecutive children (April 2016-September 2018). The SMC was assessed daily with a handheld vital microscope (integrated with incident dark field illumination) before, during, and after ECMO. Validated parameters of vessel density, perfusion, and flow quality were assessed for all vessels (diameter 2.6) increased with higher MAP (OR: 1.050, 95%CI: 1.008-1.094). Microcirculatory parameters did not significantly differ between VV and VA ECMO or between survivors and non-survivors. None of the microcirculatory parameters could predict mortality on ECMO or overall mortality. Conclusion: In this heterogeneous study population, we were not able to demonstrate an effect of ECMO on the sublingual microcirculation. Microcirculatory parameters did not change throughout ECMO treatment and did not differ between VV and VA ECMO or between survivors and non-survivors. Future research should focus on determining which neonatal and pediatric ECMO patients wou

    Coagulation complications after conversion from roller to centrifugal pump in neonatal and pediatric extracorporeal membrane oxygenation

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    Background/purpose: Coagulation complications are frequent, unwanted occurrences in extracorporeal membrane oxygenation (ECMO) treatment, possibly influenced by the pump in the ECMO-circuit. We hypothesized that fewer complications would occur with a smaller, heparin-coated ECMO system with a centrifugal pump (CP) than with one with a roller pump (RP) and that after conversion, complication rates would decrease over time. Methods: This single-center, retrospective chart study included all first neonatal and pediatric ECMO runs between 2009 and 2015. Differences between groups were assessed with Mann–Whitney U tests and Kruskal–Wallis tests. Determinants of complication rates were evaluated through Poisson regression models. The CP group was divided into three consecutive groups to assess whether complication rates decreased over time. Results: The RP group comprised 90 ECMO runs and the CP group 82. Hemorrhagic complication rates were significantly higher with the CP than with the RP, without serious therapeutic consequences, while thrombotic complications rates were unaffected. Intracranial hemorrhage rates and coagulation-related mortality rates were similar. Gained experience with the CP did not improve complication rates or su

    Effects of Cooling During Exercise on Thermoregulatory Responses of Men With Paraplegia.

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    BACKGROUND: People with spinal cord injury (SCI) have an altered afferent input to the thermoregulatory center, resulting in a reduced efferent response (vasomotor control and sweating capacity) below the level of the lesion. Consequently, core body temperature rises more rapidly during exercise in individuals with SCI compared with people who are able-bodied. Cooling strategies may reduce the thermophysiological strain in SCI. OBJECTIVE: The aim of this study was to examine the effects of a cooling vest on the core body temperature response of people with a thoracic SCI during submaximal exercise. METHODS: Ten men (mean age=44 years, SD=11) with a thoracic lesion (T4-T5 or below) participated in this randomized crossover study. Participants performed two 45-minute exercise bouts at 50% maximal workload (ambient temperature 25°C), with participants randomized to a group wearing a cooling vest or a group wearing no vest (separate days). Core body temperature and skin temperature were continuously measured, and thermal sensation was assessed every 3 minutes. RESULTS: Exercise resulted in an increased core body temperature, skin temperature, and thermal sensation, whereas cooling did not affect core body temperature. The cooling vest effectively decreased skin temperature, increased the core-to-trunk skin temperature gradient, and tended to lower thermal sensation compared with the control condition. LIMITATIONS: The lack of differences in core body temperature among conditions may be a result of the relative moderate ambient temperature in which the exercise was performed. CONCLUSIONS: Despite effectively lowering skin temperature and increasing the core-to-trunk skin temperature gradient, there was no impact of the cooling vest on the exercise-induced increase in core body temperature in men with low thoracic SCI
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