A novel ductile connection for FRP pultruded beam-to-column assemblies

The resistance, stiffness and ductility of the joints between Fibre Reinforced Polymer (FRP) members play a key role in ensuring the required structural performance of pultruded composite frames. Both bonded and bolted joints are characterised by poor mechanical performance due to brittle failure and low resistance respectively. Hybrid joints are stronger and more ductile, but are still affected by some criticisms such as (i) non-repairability, (ii) the presence of holes in the fibre-reinforced material, (iii) the difficulty of assembling a transverse beam into the joint, which is typically required for real 3D systems. To overcome such limitations, a novel ductile connection has been developed by combining ductile steel elements bonded to FRP members. The steel elements are bolted together and are designed to be weaker than the FRP profiles and adhesive. Experimental tests on beam-column assemblies have been carried out and the test results have shown that the investigated hybrid connection is characterised by adequate stiffness, resistance and high ductility. The damage is concentrated in the bolted steel elements, which can be easily replaced, confirming the repairability of the assembly

Evaluating the Surgeons' Perception of Difficulties of Two Techniques to Perform STARR for Obstructed Defecation Syndrome: A Multicenter Randomized Trial.

BACKGROUND After initial enthusiasm in the use of a dedicated curved stapler (CCS-30 Contour Transtar) to perform stapled transanal rectal resection (STARR) for obstructed defecation syndrome (ODS), difficulties have emerged in this surgical technique. OBJECTIVE First, to compare surgeons' perception of difficulties of STARR performed with only Transtar versus STARR performed with the combined use of linear staplers and Transtar to cure ODS associated with large internal prolapse and rectocele; second, to compare the postoperative incidence of the urge to defecate between the 2 STARR procedures. DESIGN AND SETTING An Italian multicenter randomized trial involving 25 centers of colorectal surgery. PATIENTS Patients with obstructed defecation syndrome and rectocele or rectal intussusception, treated between January and December 2012. INTERVENTIONS Participants were randomly assigned to undergo STARR with a curved alone stapler (CAS group) or with the combined use of linear and curved staplers (LCS group). MAIN OUTCOME MEASURES Primary end-points were the evaluation of surgeons' perception of difficulties score and the incidence of the "urge to defecate" at 3-month follow up. Secondary end-points included duration of hospital stay, rates of early and late complications, incidence of "urge to defecate" at 6 and 12 months, success of the procedures at 12 months of follow-up. RESULTS Of 771 patients evaluated, 270 patients (35%) satisfied the criteria. Follow-up data were available for 254 patients: 128 patients (114 women) in the CAS group (mean age, 52.1; range, 39-70 years) and 126 (116 women) in LCS group (mean age, 50.7 years; range, 41-75 years). The mean surgeons' perception score, was 15.36 (SD, 3.93) in the CAS group and 12.26 (SD, 4.22) in the LCS group (P < .0001; 2-sample t test). At 3-month follow-up, urge to defecate was observed in 18 (14.6%) CAS group patients and in 13 (10.7%) LCS group patients (P = .34; Fisher's exact test). These values drastically decrease at 6 months until no urge to defecate in all patients at 12 months was observed. At 12-month follow-up, a successful outcome was achieved in 100 (78.1%) CAS group patients and in 105 (83.3%) LCS group patients (P = .34; Fisher's exact test). No significant differences between groups were observed in the hospital stay and rates of early or late complications occurring after STARR. CONCLUSIONS STARR with Transtar associated with prior decomposition of prolapse, using linear staplers, seems to be less difficult than that without decomposition. Both procedures appear to be safe and effective in the treatment of obstructed defecation syndrome resulting in similar success rates and complications

Occurrence and neuroendocrine role of D-aspartic acid and N-methyl-D-aspartic acid in Ciona intestinalis

AbstractProbes for the occurrence of endogenous D-aspartic acid (D-Asp) and N-methyl-D-aspartic acid (NMDA) in the neural complex and gonads of a protochordate, the ascidian Ciona intestinalis, have confirmed the presence of these two excitatory amino acids and their involvement in hormonal activity. A hormonal pathway similar to that which occurs in vertebrates has been discovered. In the cerebral ganglion D-Asp is synthesized from L-Asp by an aspartate racemase. Then, D-Asp is transferred through the blood stream into the neural gland where it gives rise to NMDA by means of an NMDA synthase. NMDA, in turn, passes from the neuronal gland into the gonads where it induces the synthesis and release of a gonadotropin-releasing hormone (GnRH). The GnRH in turn modulates the release and synthesis of testosterone and progesterone in the gonads, which are implicated in reproduction

A djuvant treatment in patients at high risk of recurrence of thymoma: Efficacy and safety of a three-dimensional conformal radiation therapy regimen

The clinical benefits of postoperative radiation therapy (PORT) for patients with thymoma are still controversial. In the absence of defined guidelines, prognostic factors such as stage, status of surgical margins, and histology are often considered to guide the choice of adjuvant treatment (radiotherapy and/or chemotherapy). In this study, we describe our single-institution experience of three-dimensional conformal PORT administered as adjuvant treatment to patients with thymoma. METHODS: Twenty-two consecutive thymoma patients (eleven male and eleven female) with a median age of 52 years and treated at our institution by PORT were analyzed. The patients were considered at high risk of recurrence, having at least one of the following features: stage IIB or III, involved resection margins, or thymic carcinoma histology. Three-dimensional conformal PORT with a median total dose on clinical target volume of 50 (range 44-60) Gy was delivered to the tumor bed by 6-20 MV X-ray of the linear accelerator. Follow-up after radiotherapy was done by computed tomography scan every 6 months for 2 years and yearly thereafter. RESULTS: Two of the 22 patients developed local recurrence and four developed distant metastases. Median overall survival was 100 months, and the 3-year and 5-year survival rates were 83% and 74%, respectively. Median disease-free survival was 90 months, and the 5-year recurrence rate was 32%. On univariate analysis, pathologic stage III and presence of positive surgical margins had a significant impact on patient prognosis. Radiation toxicity was mild in most patients and no severe toxicity was registered. CONCLUSION: Adjuvant radiotherapy achieved good local control and showed an acceptable toxicity profile in patients with high-risk thymoma

Evolution of the ribbon-like organization of the Golgi apparatus in animal cells

The ‘‘ribbon,’’ a structural arrangement in which Golgi stacks connect to each other, is considered to be restricted to vertebrate cells. Although ribbon disruption is linked to various human pathologies, its functional role in cellular processes remains unclear. In this study, we investigate the evolutionary origin of the Golgi ribbon. We observe a ribbon-like architecture in the cells of several metazoan taxa suggesting its early emergence in animal evolution predating the appearance of vertebrates. Supported by AlphaFold2 modeling, we propose that the evolution of Golgi reassembly and stacking protein (GRASP) binding by golgin tethers may have driven the joining of Golgi stacks resulting in the ribbon-like configuration. Additionally, we find that Golgi ribbon assembly is a shared developmental feature of deuterostomes, implying a role in embryogenesis. Overall, our study points to the functional significance of the Golgi ribbon beyond vertebrates and underscores the need for further investigations to unravel its elusive biological roles

Hsp60 Response in Experimental and Human Temporal Lobe Epilepsy due to hyppocampal sclerosis

Hsp60 is widely distributed in the brain, and its alteration has been involved in different neurological disorders. Epilepsy is considered one of the most common neurological disorders and typically involves the hippocampal formation. Compelling evidence describes a role of mitochondria, oxidative stress and both innate and adaptive immunity during epileptogenesis in temporal lobe epilepsy due to hyppocampal sclerosis (TLE-HS). Here, we investigate the Hsp60 involvement in experimental and human epilepsy. Firstly, expression and distribution of Hsp60 in epileptic hippocampi of a rat model of temporal lobe epilepsy (TLE), based on the phenomenon of maximal dentate gyrus activation (MDA), using western blotting and immunohistochemistry was evaluated. Moreover, the circulating levels of Hsp60 in the plasma derived from the blood of TLE-HS patients before and after epileptic seizure and agematched controls, using ELISA were investigated. Protein level and immunostaining of Hsp60 were increased in both the ipsilateral and contralateral hippocampi of the epileptic rats. The Hsp60 up-regulation was observed on neurons somata and neuropil of the dentate gyrus (DG) and in hippocampus proper (CA3, CA1). Moreover, Hsp60 plasmatic levels in patients after epilepitic seizure, compared to levels of the same subjects before seizure was significantly higher. These results demonstrate that Hsp60 synthesis is increased in response to epileptic seizures and could be used as a biomarker for hippocampal stress response in TLE-HS. In conclusion, our findings suggest that Hsp60 could play an importanty role in TLE-HS and support the possible involvement of immunological factors in epileptogenesis

A multi-agent fuzzy consensus model in a Situation Awareness framework

In order to define systems enabling the automatic identification of occurring situations, numerous approaches employing intelligent software agents to analyse data coming from deployed sensors have been proposed. Thus, it is possible that more agents are committed to monitor the same phenomenon in the same environment. Redundancy of sensors and agents is needed, for instance, in real world applications in order to mitigate the risk of faults and threats. One of the possible side effects produced by redundancy is that agents, observing the same phenomenon, could provide discordant opinions. Indeed, solid mechanisms for reaching an agreement among these agents and produce a shared consensus on the same observations are needed. This paper proposes an approach to integrate a fuzzy-based consensus model into a Situation Awareness framework. The main idea is to consider intelligent agents as experts claiming their opinions (preferences) on a phenomenon of interest

Experimental Tests on Steel Plate-to-Plate Splices Bonded by C-FRPS Laminas with and without Wrapping

The results of an experimental investigation carried out on steel splices bonded by (Carbon-Fiber–Reinforced Polymers) C-FRPs are presented in this paper. The main aim of the study is to examine the influence of different parameters on the type of failure and on the ductility of splices. Different configurations of the specimens were considered, including butt and lapped joints using different arrangements for end anchorage of the bonded C-FRP laminas, such as (i) external bonding; and (ii) anchored jacketing with C-FRP sheets transversally wrapped to the longitudinal axis of the joints. The results in terms of failure modes and response curves are described and discussed, highlighting the potentiality of these types of bonded connections for metal structures. In particular, experimental results showed that (i) the failure modes exhibited by both butt and lapped wrapped splices were substantially similar; (ii) the wrapped anchoring is beneficial in order to achieve large deformations prior to failure, thus allowing a satisfactory ductility, even though a more timely installation process is necessary

Axisymmetric Hybrid Plasma Model for Hall Effect Thrusters

Hall Effect Thrusters (HETs) are nowadays widely used for satellite applications because of their efficiency and robustness compared to other electric propulsion devices. Computational modelling of plasma in HETs is interesting for several reasons: it can be used to predict thrusters’ operative life; moreover, it provides a better understanding of the physical behaviour of this device and can be used to optimize the next generation of thrusters. In this work, the discharge within the accelerating channel and near-plume of HETs has been modelled by means of an axisymmetric hybrid approach: a set of fluid equations for electrons has been solved to get electron temperatures, plasma potential and the discharge current, whereas a Particle-In-Cell (PIC) sub-model has been developed to capture the behaviour of neutrals and ions. A two-region electron mobility model has been incorporated. It includes electron–neutral/ion collisions and uses empirical constants, that vary as a continuous function of axial coordinates, to take into account electron–wall collisions and Bohm diffusion/SEE effects. An SPT-100 thruster has been selected for the verification of the model because of the availability of reliable numerical and experimental data. The results of the presented simulations show that the code is able to describe plasma discharge reproducing, with consistency, the physics within the accelerating channel of HETs. A small discrepancy in the experimental magnitude of ions’ expansion, due probably to boundary condition effects, has been found

Two-Tier Image Features Clustering for Iris Recognition on Mobile

Nowadays, many smartphones are provided with built-in sensors for the acquisition and the recognition of specific biometric traits of the user. This policy has been adopted since the massive use of such devices brought the user to store sensible data in them as well as effectuate sensitive transactions on-the-move. As a consequence, many biometric systems have been migrated from stand alone to mobile environments. The methodology proposed in the following presents an approach to the iris recognition in visible spectrum. Iris images are first enhanced by a fuzzy color/contrast preserving technique and then passed to a two-tier clustering: the first is based on the linear decomposition of the iris into superpixels; the second one exploits an unsupervised learning network model to built a feature vector of the iris. According to the performance obtained in terms of time and recognition rate, the method is compliant with the needs of real-time and in-movement environments