Descending necrotising mediastinitis is one of the most lethal and least frequent forms of mediastinitis. It is a life-threatening infection most frequently originating from an oropharyngeal or ...odontogenic infection.
A retrospective study of 6 patients diagnosed and treated for descending necrotising mediastinitis between 2015 and 2020 is reported.
All patients were male, mean age of 34.83 years; 66% were smokers. 83% had an orocervical infection and 34% had initial mediastinal spread. All patients were treated initially with empirical broad-spectrum antibiotics and surgical drainage, with subsequent admission to the Intensive Care Unit; only one of them required tracheostomy. The mean hospital stay was 27.37 days. After a mean follow-up of 6 months, 100% of the cases had a complete recovery.
Early diagnosis and surgical treatment combined with improved life-support treatment in intensive care units and broad-spectrum antibiotic therapy leads to a decrease in associated mortality.
Effects of solar radiation on phenolic compound concentrations and photosynthetic activity, estimated as in vivo chlorophyll fluorescence, in the brown alga Cystoseira tamariscifolia (Hudson) ...Papenfuss were analyzed in southern Spain from June 1988 to July 2000. Annual and diurnal variations of optimum quantum yield were negatively correlated with incident irradiance. Optimum quantum yield decreased as irradiance increased at noon, and yield values recovered in the afternoon suggesting a dynamic photoinhibition. The annual and daily fluctuations of phenolic compound concentration in the tissue of C. tamariscifolia showed contrasting patterns. There was an annual cycle of phenolic compound concentration in the apical thallus, which was positively correlated with incident irradiance. The increase in phenolic compounds, however, was twofold greater in the first half of the year than the decrease during the second half of the year. In contrast to the annual cycle, there appeared to be a negative correlation between phenolic compound concentration and irradiance in the summer months while no specific relationship was observed in the fall-winter months. Loss of phenolic compounds from the tissue to the surrounding water was increased as irradiation dosage increased. This suggests that the decrease of phenolic compounds during the diurnal cycle might be regulated by the exudation of these compounds at high irradiances in the field. Collectively, our results suggest that, like dynamic photoinhibition, the rapid synthesis and turnover time of phenolic compounds in the tissue of C. tamariscifolia might serve as photoprotective mechanisms against high irradiances.PUBLICATION ABSTRACT
An artificial neural network (ANN) model was developed to predict the coefficient of performance (COP) of an absorption heat transformer with a new physical design consisting of compact components, ...and its inverse (ANNi) was used to optimize the system's performance, coupled for the water purification. This ANN model takes into account the input and output temperature (T) of each duplex component (generator-condenser and evaporator-absorber), as well as the concentration of solution LiBr–H2O (X), pressure (P) and mass flow (ṁ). The best fitting training data was acquired with 16–7–1 considering a hyperbolic tangent sigmoid transfer-function in the hidden layer and a linear transfer-function in the output. Comparing the predicted and experimental data it was observed a satisfactory agreement (R2 > 0.9969 and MPE ∼ 3%). Furthermore, from this ANN model, a strategy was developed for optimization of a generator and an evaporator input temperatures using inverse artificial neural networks (ANNi) and solved by the method of genetic algorithms (GAs). The good prediction of the ANN model, as well as the optimized data using ANNi-GAs, makes it possible to control on-line the operation of the system, increasing the value of COP.
•Two duplex components were integrated as a new physical design for AHT.•ANN was developed to predict the COP performance.•Parameters were identified for optimal performance through inverse ANN.•Inverse ANN was solved with genetic algorithms.
The calculation of the performance of absorption heat transformers (AHTs) depends on multiple variables. In this work, artificial neural network (ANN) models with new configurations were developed to ...simultaneously estimate the coefficient of performance (COP) and Carnot coefficient of performance (COP
Carnot
) of an AHT prototype. The variables used to train the models were: the inlet and outlet temperatures corresponding to the main components of the AHT. The output parameters to simulate were the COP and COP
carnot
, which are important values to determine the performance and real efficiency based on the Carnot cycle, respectively. To find the appropriate model, it was necessary to explore learning algorithms, activation functions, and multilayers. The results show a good estimation of the output parameters through three configurations of the ANN model. However, based on the number of coefficients obtained during learning and the simultaneous simulation of two output parameters, a multilayer ANN model was proposed as the best configuration. Therefore, an architecture of four neurons in the first hidden layer and four neurons in the second hidden layer (08:04:04:02) was sufficient to reproduce the output parameters, achieving a value of
R
2
of 0.9265, 0.9573 and with a mean absolute percentage error of 2.41, 1.14% for COP and COP
Carnot
, respectively. In the three configurations, the use of hyperbolic tangent sigmoid activation function (TANSIG) in the hidden layers and the adjustment of the coefficients with the Levenberg–Marquardt learning algorithm obtained the best results. The influence of each of the variables selected for the ANN model was analyzed through a correlation matrix and a sensitivity analysis. Other experimental variables were added in the training of the ANN model to consult the impact caused during the simultaneous prediction of the performance coefficients.
Microglial morphology and immunophenotype have been studied extensively in aging-related neurodegenerative diseases, but to a lesser extent in the normally aged CNS, and little is known about how ...aging affects the ability of microglia to respond to neuronal injury. The goal of the current study was to determine if aging affects the ability of microglia to divide during the early response to facial nerve axotomy. In addition, we investigated the incidence of microglial cell death during later post-axotomy time points to determine if aging had an effect on microglial turnover. We employed DNA labeling with
3H-thymidine, TUNEL and lectin histochemistry after facial nerve axotomy in young (3 months), middle-aged (15 months), and old (30 months) Fisher344-Brown Norway hybrid rats. Proliferation of microglia in old rats remained significantly higher than in young rats 4 days after injury, suggesting that regulation of microglial proliferation changes with aging. There was no aging-related difference in microglial TUNEL staining at 7, 14 or 21 days post-axotomy. Lectin histochemistry in the unoperated facial nucleus revealed aging-related morphological changes in resting microglia, including hypertrophy of the cytoplasm with dense perinuclear staining. Aging-related differences in activated microglia on the lesioned side were more subtle, although many activated microglia of aged animals continued to exhibit dense perinuclear lectin reactivity. We propose that aging-related changes in morphology in conjunction with a less regulated proliferative response in the aged facial nucleus may be a reflection of microglial senescence.
The cattle tick Rhipicephalus (Boophilus) microplus is one of the most harmful ectoparasites affecting bovines worldwide. It represents a major threat to livestock industry due to the economic losses ...caused and diseases associated with these ticks. The most important tick control strategy has been the use of ixodicides, resulting in chemically resistant tick populations. It is necessary to understand the mechanisms that result in resistance so as to create new strategies increasing the lifespan of ixodicides or finding alternative targets to produce new acaricides. In this paper, in order to obtain an insight into the mechanisms that govern ixodicides resistance, we will compare the hemolymph proteome of two tick R. microplus strains, one susceptible (MJ) and one resistant (SA) to ixodicides, using HPLC and 2D electrophoresis. Significant differences were found in protein content between strains using HPLC. 2D electrophoresis revealed that 68 hemolymph protein spots were common between strains; however, 26 spots were unique to the susceptible strain MJ and 5 to the resistant strain SA. The most distinctive protein spots on the preparative gels were selected for further analyses. Nine protein spots were identified by mass fingerprinting, revealing proteins that may have a role in the ixodicides resistance or susceptibility. In this paper, we present the tick hemolymph proteome revealing a set of proteins which suggest a possible role in tick detoxification.
The leaves of Camellia sinensis (L.) are the source of tea, the second most consumed beverage worldwide. Tea contains several chemical compounds such as polyphenols (mainly catechins), caffeine, ...theophylline, L-theanine, among many others. Polyphenolic compounds are mainly responsible for its significant antioxidant properties and anticarcinogenic potential. Bladder cancer is one of the most common types of cancer, and its progression and onset are thought to be controlled by dietary and lifestyle factors. Epidemiological studies showed that the regular consumption of tea can be a preventive factor for this type of cancer, and several in vivo and in vitro studies reported that tea and its components may interfere in the cancer cells' signaling, preventing the bladder tumor progression. The mechanisms responsible for this protection include deregulation of cell cycle, induction of apoptosis while protecting the surrounding healthy bladder cells, inhibition of metastization processes, among others. Herein, we discuss the potential beneficial effects of tea and tea components in bladder cancer prevention and/or treatment, and how they can be helpful in finding new therapeutic strategies to treat this type of cancer.
The energy sector is currently undergoing a rapid transformation with the integration of power electronic converter (PEC)-interfaced renewable energy sources (RES), such as wind and solar ...photovoltaic (PV) systems, at both the transmission and distribution networks. Power system stability has been significantly influenced by this power grid transformation. This paper comprehensively reviews major power system stability issues affected due to large-scale integration of PEC-interfaced RES in power grids, with some example case studies relevant for each stability category. According to the review, stability issues are mainly originating from reduction in synchronous inertia, reduction in reactive power reserve, low short-circuit strength of the power network, and fault ride-through (FRT) strategy/capability of the PEC-interfaced RES. Decrease in synchronous inertia could affect both the rotor angle stability and the frequency stability, while decrease in short-circuit strength and reactive power reserve could cause voltage stability and rotor angle stability issues in power networks. Sub-synchronous control interactions are also receiving a lot of attention by the power industry due to increasing oscillatory stability incidents reported in power networks with PEC-interfaced RES. FRT capabilities/strategies of PEC-interfaced RES are also playing a pivotal role in power grid stability due to its influence on active and reactive power, hence more emphasis should be placed on FRT schemes of PEC-interfaced RES, since future power grids are expected to operate with 100% PEC-interfaced generation sources. Stability improvement strategies could be implemented to address multiple stability issues in PEC-interfaced power networks; however, rigorous stability studies are required to identify the optimal conditions to implement these improvement strategies. Furthermore, ongoing structural changes in power grids to accommodate remotely sited PEC-interfaced RES are also influencing the stability of power grids. Therefore, all these factors must be carefully considered by system operators when planning and operating power grids in a secure and stable manner with high penetration levels of PEC-interfaced RES.
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