Influencia del envejecimiento del preg-preg en las propiedades de los preg-preg y laminados

IV CONGRESO NACIONAL DE MATERIALES COMPUESTOS. Celebrado en Gijón, los días 21,22 y 23 de Noviembre de 2001Uno de los ensayos más empleados para recalificar prepregs es el test de calorimetría diferencial de barrido D.S.C.. Dicho test permite evaluar cómo la matriz polimérica se ha podido degradar durante el almacenamiento, dado que el objeto del test es determinar los parámetros que controlan la reacción de curado de la resina. Uno de los objetivos de este trabajo es estudiar el efecto que el envejecimiento de la resina tiene sobre los parámetros que controlan el proceso de curado y como una alteración de estos puede o no afectar a las propiedades mecánicas de los laminados.D.S.C. is one of the most used tests to recalify prepregs. This kind of test allows to evaluate how the polymeric matrix has been degraded during the storage due to the fact that the aim of the test is to determine the parameters that control the curing reaction of the resin. One of the objectives of this article is to study the effect of resin ageing on the parameters that controls the curing cycle and how a variation of these can affect the mechanical properties of the laminates.Unión Europea FD97-058

Cosmetics for acne: indications and recommendations for an evidence-based approach.

AIM: The aim of this review was to evaluate, by a thorough revision of the literature, the true efficacy of currently available topic and systemic cosmetic acne agents. METHODS: The efficacy of currently available cosmetic acne agents has been retrospectively evaluated via thorough revision of the literature on matched electronic databases (PubMed). All retrieved studies, either randomized clinical trials or clinical trials, controlled or uncontrolled were considered. RESULTS: Scientific evidence suggests that most cosmetic products for acne may enhance the clinical outcome. Cleansers should be indicated to all acne patients; those containing benzoyl peroxide or azelaic/salicylic acid/triclosan show the best efficacy profile. Sebum-controlling agents containing nicotinamide or zinc acetate may minimize excessive sebum production. Cosmetics with antimicrobial and anti-inflammatory substances such as, respectively, ethyl lactate or phytosphingosine and nicotinamide or resveratrol, may speed acne recovery. Topical corneolytics, including retinaldehyde/glycolic acid or lactic acid, induce a comedolytic effect and may also facilitate skin absorption of topical drugs. Finally, the use of specific moisturizers should be strongly recommended in all acne patients. CONCLUSION: Cosmetics, if correctly prescribed, may improve the performance of the therapy, whereas wrong procedures and/or inadequate cosmetics may worsen acne. Cosmetological recommendations may allow clinicians to make informed decisions about the role of various cosmetics and to indentify the appropriate indications and precautions. The choice of the most effective product should take into consideration the ongoing pharmacological therapy and acne type/severity as well

Automated cell-specific laser detection and ablation of neural circuits in neonatal brain tissue

Key points center dot We developed an automated system that detects neurons belonging to specific populations in vitro or in situ, maps their physical locations in three-dimensional tissue specimens and then laser ablates the cell targets\u27 one at a time, in sequence, while monitoring neural population activity electrophysiologically. center dot Two-photon Ca2+ imaging and image processing routines detect and validate target neurons based on rhythmic Ca2+ fluorescence activity patterns. center dot Visible-wavelength confocal imaging and image processing routines detect and validate target neurons that express genetically encoded fluorescent proteins. center dot High-intensity two-photon spot scanning vaporizes target neurons with specificity while minimizing damage to neighbouring tissue. center dot Physiological monitoring of network function is performed before, during and after the cell-specific laser ablations to measure the effects on network functionality in real time. Abstract A key feature of neurodegenerative disease is the pathological loss of neurons that participate in generating behaviour. To investigate network properties of neural circuits and provide a complementary tool to study neurodegeneration in vitro or in situ, we developed an automated cell-specific laser detection and ablation system. The instrument consists of a two-photon and visible-wavelength confocal imaging setup, controlled by executive software, that identifies neurons in preparations based on genetically encoded fluorescent proteins or Ca2+ imaging, and then sequentially ablates cell targets while monitoring network function concurrently. Pathological changes in network function can be directly attributed to ablated cells, which are logged in real time. Here, we investigated brainstem respiratory circuits to demonstrate single-cell precision in ablation during physiological network activity, but the technique could be applied to interrogate network properties in neural systems that retain network functionality in reduced preparations in vitro or in situ

Atoh1-dependent rhombic lip neurons are required for temporal delay between independent respiratory oscillators in embryonic mice

All motor behaviors require precise temporal coordination of different muscle groups. Breathing, for example, involves the sequential activation of numerous muscles hypothesized to be driven by a primary respiratory oscillator, the preBotzinger Complex, and at least one other as-yet unidentified rhythmogenic population. We tested the roles of Atoh1-, Phox2b-, and Dbx1-derived neurons (three groups that have known roles in respiration) in the generation and coordination of respiratory output in embryonic mice. We found that Dbx1-derived neurons are necessary for all respiratory behaviors, whereas independent but coupled respiratory rhythms persist from at least three different motor pools after eliminating or silencing Phox2b-or Atoh1-expressing hindbrain neurons. Without Atoh1 neurons, however, the motor pools become temporally disorganized and coupling between independent respiratory oscillators decreases. We propose Atoh1 neurons tune the sequential activation of independent oscillators essential for the fine control of different muscles during breathing

Identification of the Pre-Botzinger Complex Inspiratory Center in Calibrated “Sandwich” Slices from Newborn Mice with Fluorescent Dbx1 Interneurons

Inspiratory active pre‐Bötzinger complex (preBötC) networks produce the neural rhythm that initiates and controls breathing movements. We previously identified the preBötC in the newborn rat brainstem and established anatomically defined transverse slices in which the preBötC remains active when exposed at one surface. This follow‐up study uses a neonatal mouse model in which the preBötC as well as a genetically defined class of respiratory interneurons can be identified and selectively targeted for physiological recordings. The population of glutamatergic interneurons whose precursors express the transcription factor Dbx1 putatively comprises the core respiratory rhythmogenic circuit. Here, we used intersectional mouse genetics to identify the brainstem distribution of Dbx1‐derived neurons in the context of observable respiratory marker structures. This reference brainstem atlas enabled online histology for generating calibrated sandwich slices to identify the preBötC location, which was heretofore unspecified for perinatal mice. Sensitivity to opioids ensured that slice rhythms originated from preBötC neurons and not parafacial respiratory group/retrotrapezoid nucleus (pFRG/RTN) cells because opioids depress preBötC, but not pFRG/RTN rhythms. We found that the preBötC is centered ~0.4 mm caudal to the facial motor nucleus in this Cre/lox reporter mouse during postnatal days 0–4. Our findings provide the essential basis for future optically guided electrophysiological and fluorescence imaging‐based studies, as well as the application of other Cre‐dependent tools to record or manipulate respiratory rhythmogenic neurons. These resources will ultimately help elucidate the mechanisms that promote respiratory‐related oscillations of preBötC Dbx1‐derived neurons and thus breathing

Physiological and morphological properties of Dbx1-derived respiratory neurons in the pre-Botzinger complex of neonatal mice

Key points center dot The transcription factor Dbx1 gives rise to putatively respiratory rhythm-generating neurons in the pre-Botzinger complex. Comparative analysis of Dbx1-derived (Dbx1+) and non-Dbx1- derived (Dbx1) neurons can help elucidate the cellular bases of respiratory rhythm generation. center dot In vitro, Dbx1+ neurons activate earlier in the respiratory cycle, discharge larger magnitude inspiratory bursts and exhibit a lower rheobase compared with Dbx1 neurons. center dot The Dbx1+ neurons tend to express the intrinsic currents IA (transient outward A-current) and Ih (hyperpolarization-activated current) in diametric opposition, which may facilitate temporal summation of excitatory synaptic inputs, whereas the Dbx1 neurons show no significant pattern of expression regarding IA and Ih. center dot The Dbx1+ neurons exhibit smooth, spineless dendrites that project in the transverse plane, whereas the Dbx1 neurons are confined to the transverse plane to a lesser extent and sometimes exhibit spines. center dot The properties of Dbx1+ neurons that may contribute to respiratory rhythmogenesis include a high level of excitability linked to ongoing network activity and dendritic properties that may facilitate synaptic integration. Abstract Breathing in mammals depends on an inspiratory-related rhythm that is generated by glutamatergic neurons in the pre-Botzinger complex (preBotC) of the lower brainstem. A substantial subset of putative rhythm-generating preBotC neurons derive from a single genetic line that expresses the transcription factor Dbx1, but the cellular mechanisms of rhythmogenesis remain incompletely understood. To elucidate these mechanisms, we carried out a comparative analysis of Dbx1-expressing neurons (Dbx1+) and non-Dbx1-derived (Dbx1) neurons in the preBotC. Whole-cell recordings in rhythmically active newborn mouse slice preparations showed that Dbx1+ neurons activate earlier in the respiratory cycle and discharge greater magnitude inspiratory bursts compared with Dbx1 neurons. Furthermore, Dbx1+ neurons required less input current to discharge spikes (rheobase) in the context of network activity. The expression of intrinsic membrane properties indicative of A-current (IA) and hyperpolarization-activated current (Ih) tended to be mutually exclusive in Dbx1+ neurons. In contrast, there was no such relationship in the expression of currents IA and Ih in Dbx1 neurons. Confocal imaging and digital morphological reconstruction of recorded neurons revealed dendritic spines on Dbx1 neurons, but Dbx1+ neurons were spineless. The morphology of Dbx1+ neurons was largely confined to the transverse plane, whereas Dbx1 neurons projected dendrites to a greater extent in the parasagittal plane. The putative rhythmogenic nature of Dbx1+ neurons may be attributable, in part, to a higher level of intrinsic excitability in the context of network synaptic activity. Furthermore, Dbx1+ neuronal morphology may facilitate temporal summation and integration of local synaptic inputs from other Dbx1+ neurons, taking place largely in the dendrites, which could be important for initiating and maintaining bursts and synchronizing activity during the inspiratory phase

Morphology of Dbx1 respiratory neurons in the preBotzinger complex and reticular formation of neonatal mice

The relationship between neuron morphology and function is a perennial issue in neuroscience. Information about synaptic integration, network connectivity, and the specific roles of neuronal subpopulations can be obtained through morphological analysis of key neurons within a microcircuit. Here we present morphologies of two classes of brainstem respiratory neurons. First, interneurons derived from Dbx1-expressing precursors (Dbx1 neurons) in the preBotzinger complex (preBotC) of the ventral medulla that generate the rhythm for inspiratory breathing movements. Second, Dbx1 neurons of the intermediate reticular formation that influence the motor pattern of pharyngeal and lingual movements during the inspiratory phase of the breathing cycle. We describe the image acquisition and subsequent digitization of morphologies of respiratory Dbx1 neurons from the preBotC and the intermediate reticular formation that were first recorded in vitro. These data can be analyzed comparatively to examine how morphology influences the roles of Dbx1 preBotC and Dbx1 reticular interneurons in respiration and can also be utilized to create morphologically accurate compartmental models for simulation and modeling of respiratory circuits

Contemporary nursing care based on Watson’s theory

The study utilized a descriptive, correlational design. A purposive criterion sampling was employed using a paper and pen questionnaire based on the theory by Jean Watson on her ten carative factors. The study attempted to answer the level of care rendered by the nurses towards their patients and if there was a noteworthy association among the level of care rendered by the nurses and the patient’s demographic profile (age and gender) and nurse’s profile (gender; and hospital classification). As to the Level of Care Rendered by the Nurses Towards their Patients, the computed mean reveal an interpretation of very good. Patient’s profile and the level of care did not yield a significant relationship. There was a noteworthy association among the level of care and nurse’s gender (p = 0.012) on the area where the nurse practices loving kindness and composure inside framework of caring awareness towards patients. The level of care and the hospital classification findings revealed significant relationship on two items (p = 0.020 and .048). The level of care in terms of the nurse assisting with basic needs, with an intentional caring consciousness, administering “human care essentials”, which potentiate alignment of mind, body, spirit, wholeness, and unity of being in all aspects of care; tending to both the embodied spirit and evolving spiritual emergence are better experienced by patients in government hospitals. Based on the findings Cebuano nurses were very good in their nursing care towards their patients