High-cycle fatigue strength of a pultruded composite material

Dealing with composites in polymeric matrix, the pultruded ones are among the more suitable for large production rates and volumes. For this reason, their use is increasing also in structural applications in civil and mechanical engineering. However, their use is still limited by the partial knowledge of their fatigue behaviour; in many applications it is, indeed, required a duration of many millions of cycles, while most of the data that can be found in literature refer to a maximum number of cycles equal to 3 millions. In this paper a pultruded composite used for manufacturing structural beams is considered and its mechanical behaviour characterized by means of static and high-cycle fatigue tests. The results allowed to determine the S-N curve of the material and to assess the existence of a fatigue limit. Observations at the scanning electronic microscope (SEM) allowed to evaluate the damage mechanisms involved in the static and fatigue failure of the material

Integral field spectroscopy with SINFONI of VVDS galaxies. II. The mass-metallicity relation at 1.2 < z < 1.6

This work aims to provide a first insight into the mass-metallicity (MZ) relation of star-forming galaxies at redshift z~1.4. To reach this goal, we present a first set of nine VVDS galaxies observed with the NIR integral-field spectrograph SINFONI on the VLT. Oxygen abundances are derived from empirical indicators based on the ratio between strong nebular emission-lines (Halpha, [NII]6584 and [SII]6717,6731). Stellar masses are deduced from SED fitting with Charlot & Bruzual (2007) population synthesis models, and star formation rates are derived from [OII]3727 and Halpha emission-line luminosities. We find a typical shift of 0.2-0.4 dex towards lower metallicities for the z~1.4 galaxies, compared to the MZ-relation in the local universe as derived from SDSS data. However, this small sample of eight galaxies does not show any clear correlation between stellar mass and metallicity, unlike other larger samples at different redshift (z~0, z~0.7, and z~2). Indeed, our galaxies lie just under the relation at z~2 and show a small trend for more massive galaxies to be more metallic (~0.1 logarithmic slope). There are two possible explanations to account for these observations. First, the most massive galaxies present higher specific star formation rates when compared to the global VVDS sample which could explain the particularly low metallicity of these galaxies as already shown in the SDSS sample. Second, inflow of metal-poor gas due to tidal interactions could also explain the low metallicity of these galaxies as two of these three galaxies show clear signatures of merging in their velocity fields. Finally, we find that the metallicity of 4 galaxies is lower by ~0.2 to 0.4 dex if we take into account the N/O abundance ratio in their metallicity estimate.Comment: 7 pages, 4 figures, accepted in A&A Comments: Comments: more accurate results with better stellar mass estimate

Spontaneous Participation in Secondary Prevention Programs : The Role of Psychosocial Predictors

Disease prevention is a multifaceted construct that has been widely studied. Nevertheless, in spite of its importance, it is still not sufficiently considered by the general population. Since the reasons for this lack of consideration are not yet fully understood, we created an Online Prevention Survey (OPS) to investigate the role of both sociodemographic and psychological factors in predicting individuals\u2019 spontaneous participation in secondary prevention programs. The results revealed that younger people, men, manual workers, unemployed people, and those who do not regularly practise physical activity were less likely to spontaneously participate in such programs. Furthermore, an analysis of the psychological determinants of the willingness to participate in secondary prevention programs showed that depressive symptoms negatively predict it, while an individual\u2019s perception of receiving high social support acts as a positive predictor. Based on these results, we suggest the need for implementing new tailored approaches to promote prevention initiatives to those segments of the population which are more reluctant to spontaneously undertake prevention paths

Mucopexy-recto anal lifting: a standardized minimally invasive method of managing symptomatic hemorrhoids, with an innovative suturing technique and the HemorPex System&#174;

BACKGROUND: Conservative surgery of hemorrhoidal disease is less painful than traditional hemorrhoidectomy, and mucopexy has less risk of serious postoperative complications than stapled hemorrhoidopexy. The aim of this study was to evaluate the safety and effectiveness of a standardized, modified hemorrhoidopexy, named Mucopexy-Recto Anal Lifting (MuRAL) with the HemorPex System (HPS) in patients with symptomatic III and IV degree hemorrhoids. METHODS: Patients were enrolled from May 2013 to Dec 2015 and operated on with the MuRAL technique, based on arterial ligation and mucopexy at 6 locations, using a standardized clockwise/anti-clockwise rotation sequence of the HPS anoscope. Follow-up controls were carried out by independent observers, as follows: a digital exploration 3 weeks after the intervention, digital exploration plus proctoscopy at 3 and 12 months and repeated at a 12 months interval. Patients who did not strictly follow the postoperative controls were excluded from the study. Primary outcome measurement was the recurrence rate. Secondary measurements were: operative time, hospital stay, postoperative pain, postoperative symptoms and satisfaction score. RESULTS: We operated on 126 patients (72 males, mean age 53.9, range 29-83): 87 (69.6%) with III degree and 39 with IV degree hemorrhoids; 13 patients had a MuRAL as a revisional procedure of a previous operation for hemorrhoids. Mean duration of follow-up was 554 days (range 281-1219). Four patients were excluded from the study. One-year recurrence rate was 4.1%. The mean duration of the intervention was 29.5 minutes (range 23-60) and 92 patients (73%) were discharged during the same day of the operation. Pain VAS Score in the first, second and third postoperative day was 3.9, 2.5, and 1.9, respectively. Twenty-two patients (18%), all submitted to spinal anesthesia, had postoperative acute urinary retention. Fecal urgency, observed in 18.8% of patients at the first control, disappeared within one year after the operation. Mean time to return to normal activity was 8 days (range 5 -10). The patient satisfaction scores at one-year follow up were 31.1% excellent, 57.4% good, 7.4% fairly good and 4.1% poor. In patients with III degree hemorrhoids operative time was significantly shorter, postoperative pain better and transient fecal urgency lower than in IV degree patients. In our experience the standardization of MuRAL operation with HPS, turned out to be a safe and effective minimally invasive approach in managing symptomatic III and IV degree hemorrhoids, avoiding the risk of severe complications, with the possibility to perform a redo-MuRAL in the event of recurrence. CONCLUSIONS: In our series up to 88% of the patients reported a good, or excellent one-year satisfaction score. Further comparative randomized studies with longer follow-up period are needed

Mucopexy-Recto Anal Lifting (MuRAL) in managing obstructed defecation syndrome associated with prolapsed hemorrhoids and rectocele : preliminary results

Purpose: Treatment of rectocele associated with prolapsed hemorrhoids is a debated topic. Transanal stapling achieved good midterm results in patients with symptoms of obstructed defecation, nevertheless a number of severe complications have been reported. The aim of this study was to evaluate the safety and efficacy of a new endorectal manual technique in patients with obstructed defecation due to the combination of muco-hemorrhoidal prolapse and rectocele. Methods: Patients enrolled after preoperative obstructed defecation syndrome (ODS) score, defecography and anoscopy were submitted to the novel Mucopexy-Recto Anal Lifting (MuRAL) combined with a modified Block procedure, and followed up by independent observers with digital exploration 3 weeks postoperatively, and digital exploration plus anoscopy at 3, 6, and 12 months. Operative time, hospital stay, numerating rating scale (NRS), ODS, satisfaction scores, and recurrence rate were recorded. Results: Mean operative time was 35.7 minutes. Fifty-six patients completed 1-year follow-up: 7.1% had acute urinary retention, NRS score was &lt; 3 from the third postoperative day, mean time of daily activity resumption was 12 days, none had persistent fecal urgency, 82% declared excellent/good satisfaction score, significant improvement of 6- and 12-month ODS score, no recurrence of rectocele, and 7.1% recurrence of prolapsed hemorrhoids were observed. Conclusion: MuRAL associated with modified Block technique gave no severe complications and resulted in a safe and effective approach to symptomatic rectocele associated with muco-rectal prolapse. Further randomized studies, larger series, and longer follow-up are needed. [Ann Surg Treat Res 2020;98(5):277-282

Effective absorbing column density in the gamma-ray burst afterglow X-ray spectra

We investigate the scaling relation between the observed amount of absorption in the X-ray spectra of Gamma Ray Burst (GRB) afterglows and the absorber redshift. Through dedicated numerical simulations of an ideal instrument, we establish that this dependence has a power law shape with index 2.4. However, for real instruments, this value depends on their low energy cut-off, spectral resolution and on the detector spectral response in general. We thus provide appropriate scaling laws for specific instruments. Finally, we discuss the possibility to measure the absorber redshift from X-ray data alone. We find that 10^5-10^6 counts in the 0.3-10 keV band are needed to constrain the redshift with 10% accuracy. As a test case we discuss the XMM-Newton observation of GRB 090618 at z=0.54. We are able to recover the correct redshift of this burst with the expected accuracy.Comment: MNRAS accepted. 6 figures. 3 table

Advances in nanoscopic mechanobiological structure-property relationship in human bones for tailored fragility prevention

It is well documented that fragility fractures represent an enormous health, economic and psycho-social burden, leading to severe pain, loss of mobility, and even death. While clinical approaches focusing on macro down to micro-scale damage in bones are often ineffective to diagnose early fracture occurrence, nano-scale investigations are opening new frontiers for targeted fragility prevention. This review highlights a novel triad that merges advanced nano-imaging techniques, nano-mechanical characterization and finite element/molecular dynamics-based computational models to elucidate the structure-property relationship that leads to bone fractures. Techniques such as atomic force microscopy and high-resolution electron microscopy enable the evaluation of mechanobiological mechanisms and damage occurrence at the sub-micro scale, providing visualization of bone ultrastructure. Simultaneously, nanoindentation and micropillar compression offer precise measurements of mechanical properties, unraveling how bone responds to diverse forces. Pertaining computational tools, nano-scale modeling simulations explore the behavior of bone components under varying conditions, yielding crucial insights into fracture mechanisms. This holistic triad unveils interactions between mineralized collagen fibrils, cross-links, and bone structures, leading to targeted prevention and personalized treatment of bone fragility, by addressing their root causes at the nano-scale, potentially lowering their incidence and severity