Evaluation of the influence of voids on 3D representative volume elements of fiber-reinforced polymer composites using CUF micromechanics

This paper presents numerical results on the micromechanical linear analysis of representative volume elements (RVE) containing voids. The modeling approach is the micromechanical framework within the Carrera Unified Formulation in which fibers and matrix are 1D finite elements (FE) with enriched kinematics and component-wise capabilities. RVE models are 3D and consider all six stress components. Such a modeling strategy leads to a twofold reduction of the degrees of freedom as compared to 3D FE. The numerical assessments address the influence of the volume fraction and distribution of voids, including comparisons with data from the literature and statistical studies regarding homogenized properties and stress fields. The proposed modeling approach can capture the local effects due to the presence of voids, and, given its computational efficiency, the present framework is promising for nonlinear analysis, such as progressive failure

A Formal Approach for Reasoning About a Class of Diffie-Hellman Protocols

We present a framework for reasoning about secrecy in a class of Diffie-Hellman protocols. The technique, which shares a conceptual origin with the idea of a rank function, uses the notion of a message-template to determine whether a given value is generable by an intruder in a protocol model. Traditionally, the rich algebraic structure of Diffie-Hellman messages has made it difficult to reason about such protocols using formal, rather than complexity-theoretic, techniques. We describe the approach in the context of the MTI A(0) protocol, and derive the conditions under which this protocol can be considered secure

Acute and chronic nicotine exposures differentially affect central serotonin 2A receptor function: Focus on the lateral habenula

Nicotine addiction is a serious public health problem causing millions of deaths worldwide. Serotonin (5-hydroxytryptamine; 5-HT) is involved in central nervous system (CNS) nicotine effects, and it has been suggested as a promising pharmacological target for smoking cessation. In this regard, what is particularly interesting are the 5-HT2A receptors (5-HT2ARs) and the lateral habenula (LHb), a central area in nicotine addiction that we showed to be under a strong 5-HT2AR-modulation. Single-cell extracellular recording of LHb neurons was used to study the 5-HT2AR function by intravenously administrating the potent agonist TCB-2. Acute nicotine (2 mg/kg, intraperitoneal, i.p.) and chronic nicotine (6 mg/kg/day for 14 days) differently affected both the 5-HT2AR-immuno reactive (IR) neuron number and the 5-HT2AR immunostaining area in the different brain areas studied. After acute nicotine, TCB-2 cumulative doses (5–640 μg/kg, intravenous, i.v.) bidirectionally affected the activity of 74% of LHb recorded neurons. After chronic nicotine treatment, TCB-2 was only capable of decreasing the LHb firing rate. The expression of 5-HT2AR under acute and chronic nicotine exposure was studied in the LHb and in other brain areas involved in nicotine effects in rats by using immunohistochemistry. These data reveal that acute and chronic nicotine differentially affect the 5-HT2AR function in different brain areas and this might be relevant in nicotine addiction and its treatment

Lateral habenula 5-ht2c receptor function is altered by acute and chronic nicotine exposures

none9siSerotonin (5-HT) is important in some nicotine actions in the CNS. Among all the 5-HT receptors (5-HTRs), the 5-HT2CR has emerged as a promising drug target for smoking cessation. The 5-HT2CRs within the lateral habenula (LHb) may be crucial for nicotine addiction. Here we showed that after acute nicotine tartrate (2 mg/kg, i.p.) exposure, the 5-HT2CR agonist Ro 60-0175 (5–640 µg/kg, i.v.) increased the electrical activity of 42% of the LHb recorded neurons in vivo in rats. Conversely, after chronic nicotine treatment (6 mg/kg/day, i.p., for 14 days), Ro 60-0175 was incapable of affecting the LHb neuronal discharge. Moreover, acute nicotine exposure increased the 5-HT2CR-immunoreactive (IR) area while decreasing the number of 5-HT2CR-IR neurons in the LHb. On the other hand, chronic nicotine increased both the 5-HT2CR-IR area and 5-HT2CR-IR LHb neurons in the LHb. Western blot analysis confirmed these findings and further revealed an increase of 5-HT2CR expression in the medial prefrontal cortex after chronic nicotine exposure not detected by the immunohistochemistry. Altogether, these data show that acute and chronic nicotine exposure differentially affect the central 5-HT2CR function mainly in the LHb and this may be relevant in nicotine addiction and its treatment.openBombardi C.; Delicata F.; Tagliavia C.; Grandis A.; Pierucci M.; Gammazza A.M.; Casarrubea M.; De Deurwaerdere P.; Di Giovanni G.Bombardi C.; Delicata F.; Tagliavia C.; Grandis A.; Pierucci M.; Gammazza A.M.; Casarrubea M.; De Deurwaerdere P.; Di Giovanni G

Nicotine modulation of the lateral habenula/ventral tegmental area circuit dynamics: An electrophysiological study in rats

Nicotine, the addictive component of tobacco, has bivalent rewarding and aversive properties. Recently, the lateral habenula (LHb), a structure that controls ventral tegmental area (VTA) dopamine (DA) function, has attracted attention as it is potentially involved in the aversive properties of drugs of abuse. Hitherto, the LHb-modulation of nicotine-induced VTA neuronal activity in vivo is unknown. Using standard single-extracellular recording in anesthetized rats, we observed that intravenous administration of nicotine hydrogen tartrate (25–800 μg/kg i.v.) caused a dose-dependent increase in the basal firing rate of the LHb neurons of nicotine-naïve rats. This effect underwent complete desensitization in chronic nicotine (6 mg/kg/day for 14 days)-treated animals. As previously reported, acute nicotine induced an increase in the VTA DA neuronal firing rate. Interestingly, only neurons located medially (mVTA) but not laterally (latVTA) within the VTA were responsive to acute nicotine. This pattern of activation was reversed by chronic nicotine exposure which produced the selective increase of latVTA neuronal activity. Acute lesion of the LHb, similarly to chronic nicotine treatment, reversed the pattern of DA cell activation induced by acute nicotine increasing latVTA but not mVTA neuronal activity. Our evidence indicates that LHb plays an important role in mediating the effects of acute and chronic nicotine within the VTA by activating distinct subregional responses of DA neurons. The LHb/VTA modulation might be part of the neural substrate of nicotine aversive properties. By silencing the LHb chronic nicotine could shift the balance of motivational states toward the reward

Inter- and intra-interviewer reliability of italian version of pediatric evaluation of disability inventory (i-pedi)

Background. Childhood disabilities determine a range of immediate and long-term economic costs that have important implications for the well-being of the child, the family and the society. The Pediatric Evaluation of Disability Inventory (PEDI) measures capability and performance in children aged between 6 months and 7.5 years. It contains three scales: Functional Skills Scales (FSS), Caregiver Assistance Scale (CAS) and Modifications Scale (MS). The present study evaluated the measurement properties of the Italian version of the PEDI (PEDI-I) in patients with spastic cerebral palsy (CP). Study design. Reliability study. Methods. The original PEDI was translated – including a cross-cultural adaptation - into Italian. Internal consistency and test-retest reliability were evaluated. Results. Fifty-eight children with CP were recruited. According to inter-interviewer reproducibility, the FSS domain revealed intraclass correlation coefficient (ICC) values ranging between 0.94 and 1.00. CAS domain revealed ICC values ranging between 0.94 and 1.00. The SEM values ranged between 3.25 (SDD=8.98) for SF and 5.24 for SC (SDD=14.5). According to intra-interviewer reproducibility, the FSS domain revealed ICC values ranging between 0.99 and 1.00. CAS domain revealed ICC values ranging between 0.92 and 0.99. The SEM values ranged between 3.44 (SDD=9.5) for SF and 3.75 for SC (SDD=10.36). The inter-interviewer and intra-interviewer reproducibility results showed very high ICC values for both FFS and CAS domains. Cronbach’s α ranged between 0.94 and 0.99, indicating excellent internal consistency within each domain of the PEDI-I. Conclusions. The inter-interviewer and intra-interviewer reproducibility results of PEDI-I showed very high ICC values for FFS and CAS domains. Therefore, we recommend its application to evaluate the effect of treatment in children with CP