Titanium versus absorbable tacks comparative study (TACS): a multicenter, non-inferiority prospective evaluation during laparoscopic repair of ventral and incisional hernia: study protocol for randomized controlled trial

BACKGROUND: Laparoscopic repair of ventral and incisional hernias has gained popularity since many studies have reported encouraging results in terms of outcomee and recurrence. Choice of mesh and fixation methods are considered crucial issues in preventing recurrences and complications. Lightweight meshes are considered the first choice due to their biomechanical properties and the ability to integrate into the abdominal wall. Titanium helicoidal tacks still represent the "gold standard" for mesh fixation, even if they have been suggested to be involved in the genesis of post-operative pain and complications. Recently, absorbable tacks have been introduced, under the hypothesis that there will be no need to maintain a permanent fixation device after mesh integration. Nevertheless, there is no evidence that absorbable tacks may guarantee the same results as titanium tacks in terms of strength of fixation and recurrence rates. The primary end point of the present trial is to test the hypothesis that absorbable tacks are non-inferior to titanium tacks in laparoscopic incisional and ventral hernia repair (LIVHR) by lightweight polypropylene mesh, in terms of recurrence rates at 3-year follow-up. Surgical complications, post-operative stay, comfort and pain are secondary end points to be assessed. METHODS/DESIGN: Two hundred and twenty patients with ventral hernia will be randomized into 2 groups: Group A (110) patients will be submitted to LIVHR by lightweight polypropylene mesh fixed by titanium tacks; Group B (110) patients will be submitted to LIVHR by lightweight polypropylene mesh fixed by absorbable tacks. DISCUSSION: A few retrospective studies have reported similar results when comparing absorbable versus non-absorbable tacks in terms of intraoperative and early post-operative outcomes. These studies have the pitfalls to be retrospective evaluation of small series of patients, and the reported results still need to be validated by larger series and prospective studies. The aim of the present trial is to investigate and test the non-inferiority of absorbable versus non-absorbable tacks in terms of hernia recurrence rates, in order to assess whether the use of absorbable tacks may achieve the same results as non-absorbable tacks in mid-term and long-term settings

Stability analysis of a pneumatically actuated inverted pendulum

This paper deals with the stabilization of an inverted pendulum on cart; the latter is pneumatically actuated by a double acting cylinder controlled by low cost proportional valves. In particular, a numerical model of whole system is developed in order to find the ability of the pneumatic actuation in stabilizing the pendulum and evaluate its bandwidth. A cascade of two control loops (the inner one for the pendulum angle, the outer one for the cart displacement) are analyzed and proper compensators are defined. The possibility of introducing an additional loop to control the force exerted by the actuator on the cart is evaluated

An aerostatic pad with an internal pressure control

Because of their almost zero friction and wear, aerostatic pads are widely used in applications where very precise positioning is required. However, this kind of bearing suffers from poor damping and low specific stiffness. This paper presents a new compensation strategy to increase air pad stiffness. This method exploits a custom-built pneumatic valve which can be easily integrated with any commercial pad. The design and the working principle of the proposed system are described and studied with the aid of a lumped parameter model. The effectiveness of the proposed compensation is numerically and experimentally evaluated. The results demonstrate that the solution represents a good and cost-effective method to enhance the static stiffness of aerostatic pads

Unbalance Response Analysis of a Spindle Supported on Gas Bearings: A Comparison between Different Approaches

Gas journal bearings are widely employed in high-speed spindles for the micromachining industry. Compared to their oil and rolling counterparts, gas bearings have a longer life span, lower friction and a lower level of noise. In order to design accurate high-speed spindles supported by externally pressurized gas bearings, it is vital to analyze the characteristics of rotor bearing systems. In this paper, we present an analysis of the unbalance response of a high-speed spindle supported by gas journal bearings. A number of aspects to enhance the accuracy of the system are discussed. We performed the analysis by considering a nonlinear and a linearized numerical model validated through experimental measurements

Air Pad Controlled by Means of a Diaphragm-Valve: Static and Dynamic Behaviour

This paper presents the analysis of the static and dynamic performance of a passively compensated air pad. The proposed method consists in the integration of a custom-built diaphragm valve and a commercial aerostatic pad. A lumped model is used to simulate the static and dynamic performance of the pad. Results demonstrate that the proposed method is very effective when the system works with excitation frequencies below 10 Hz

On the Design of a Diaphragm Valve for Aerostatic Bearings

Because of their almost zero friction, cleanness and long life, aerostatic bearings are commonly used in many applications where high precision of positioning is required, e.g. machine tools, measuring machines, semiconductor manufacturing and power board testing. However, air bearings suffer from low relative stiffness and poor damping. Active and passive compensation are two effective methods to enhance the static and dynamic performance of these kinds of bearings. Despite their higher performance, active compensation solutions are too expensive to be used in industrial applications, as a consequence of the costs related to their controllers, actuators and sensors. This paper presents the design and performance of a passive compensation method that exploits a diaphragm valve. Thanks to its ease of integration, satisfactory performance and relatively low cost, this method could be a valuable solution to increasing the stiffness of aerostatic bearings. This work provides a procedure to design diaphragm valves depending on the type of the integrated pad and the desired nominal air gap height. Results demonstrate that, once correctly designed, the diaphragm valve makes it possible to obtain bearings with quasi-static infinite stiffness at the selected air gap height

Public perceptions and behavioural responses to the first COVID-19 pandemic wave in Italy: Results from the iCARE study

Background: Italy was the first European country to be affected by COVID-19. Considering that many countries are currently battling the 2nd wave of the pandemic, understanding people's perceptions and responses to government policies remains critical for informing on-going mitigation strategies. We assessed attitudes towards COVID-19 policies, levels of adherence to preventive behaviours, and the association between COVID-19 related concerns and adherence levels. Methods: We recruited a convenience sample of Italian individuals from an international cross-sectional survey (www.icarestudy.com) from March 27th to May 5th 2020. Multivariate regression models were used to test the association between concerns and the adoption of preventive measures. Results: The survey included 1,332 participants (female (68%), younger than 25 (57%)) that reported high awareness (over 96%) and perceived importance (88%) of policies. We observed varied levels of adherence to: hand washing (96%), avoiding social gatherings (96%), self-isolation if suspected or COVID-19 positive (77%). Significantly lower adherence to self-isolation was reported by individuals with current employment. High levels of concerns regarding health of other individuals and country economy were reported. Only health concerns for others were significantly associated with higher adherence to hand washing behaviour. Conclusions: In order to inform current/future government strategies, we provide insights about population's responses to the initial pandemic phase in Italy. Communication approaches should consider addressing people's concerns regarding the health of other individuals to motivate adherence to prevention measures. Provision of social and economic support is warranted to avoid unequal impacts of governmental policies and allow effective adherence to self-isolating measures. Keywords: COVID-19; cross-sectional study; population concerns; preventive behviours

Glutathione infusion before primary percutaneous coronary intervention: A randomised controlled pilot study

Objective: In the setting of reperfused ST-elevation myocardial infarction (STEMI), increased production of reactive oxygen species (ROS) contributes to reperfusion injury. Among ROS, hydrogen peroxide (H2O2) showed toxic effects on human cardiomyocytes and may induce microcirculatory impairment. Glutathione (GSH) is a water-soluble tripeptide with a potent oxidant scavenging activity. We hypothesised that the infusion of GSH before acute reoxygenation might counteract the deleterious effects of increased H2O2 generation on myocardium. Methods: Fifty consecutive patients with STEMI, scheduled to undergo primary angioplasty, were randomly assigned, before intervention, to receive an infusion of GSH (2500 mg/25 mL over 10 min), followed by drug administration at the same doses at 24, 48 and 72 hours elapsing time or placebo. Peripheral blood samples were obtained before and at the end of the procedure, as well as after 5 days. H2O2 production, 8-iso-prostaglandin F2α (PGF2α) formation, H2O2 breakdown activity (HBA) and nitric oxide (NO) bioavailability were determined. Serum cardiactroponin T (cTpT) was measured at admission and up to 5 days. Results: Following acute reperfusion, a significant reduction of H2O2 production (p=0.0015) and 8-iso-PGF2α levels (p=0.0003), as well as a significant increase in HBA (p<0.0001)and NO bioavailability (p=0.035), was found in the GSH group as compared with placebo. In treated patients, attenuated production of H2O2 persisted up to 5 days from the index procedure (p=0.009) and these changes was linked to those of the cTpT levels (r=0.41, p=0.023). Conclusion: The prophylactic and prolonged infusion of GSH seems to determine a rapid onset and persistent blunting of H2O2 generation improving myocardial cell survival. Nevertheless, a larger trial, adequately powered for evaluation of clinical endpoints, is ongoing to confirm the current finding

Laparoscopic splenectomy in the management of benign and malignant hematologic diseases

Objectives: The use of laparoscopy to treat malignant hematological diseases is not completely accepted. Our aim was to analyze operative and postoperative results of laparoscopic splenectomy performed for benign versus malignant hematological disorders. Methods: Between 1994 and 2003, 76 consecutive patients underwent laparoscopic splenectomy. The first 38 cases were performed by using an anterior approach, whereas in the remaining 38 cases a semilateral position was used. Results: Baseline characteristics showed that patients with malignant diseases were significantly older (56.9 vs 32.6 years, P 0.001). Seventy-two (94.7%) procedures were completed laparoscopically. Conversion was required in 4 cases (5.2%). Mean operative time was 138.5 minutes for benign and 151.0 minutes for malignant diseases, (P 0.05, ns). The hand-assisted technique was used in 3 patients with massive splenomegaly. Pathologic features showed that spleen volume was higher in patients with malignant diseases (mean interpole diameter 18.1 cm vs 13.7 cm, P 0.001). Massive splenomegaly (interpole diameter over 20 cm, weight over 1000 g) was present in 13 patients (17.1%); 9 had malignant diseases. Overall perioperative mortality was 1.3% and major postoperative complications occurred in 6 patients (7.8%). Postoperative splenoportal partial thrombosis was identified in 9.7% of patients. Conclusions: Laparoscopic splenectomy is a well-accepted, less-invasive procedure for hematological disorders. Neoplastic diseases or splenomegaly, or both, do not seem to limit the indications for a minimally invasive approach after the learning curve

Young Women With Acute Myocardial Infarction: Risk Prediction Model for 1-Year Hospital Readmission

Background Although young women ( aged ≤ 55 years) are at higher risk than similarly aged men for hospital readmission within 1 year after an acute myocardial infarction (AMI), no risk prediction models have been developed for them. The present study developed and internally validated a risk prediction model of 1-year post-AMI hospital readmission among young women that considered demographic, clinical, and gender-related variables. Methods We used data from the US Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients (VIRGO) study (n = 2007 women), a prospective observational study of young patients hospitalized with AMI. Bayesian model averaging was used for model selection and bootstrapping for internal validation. Model calibration and discrimination were respectively assessed with calibration plots and area under the curve. Results Within 1-year post-AMI, 684 women (34.1%) were readmitted to the hospital at least once. The final model predictors included: any in-hospital complication, baseline perceived physical health, obstructive coronary artery disease, diabetes, history of congestive heart failure, low income ( < $30,000 US), depressive symptoms, length of hospital stay, and race (White vs Black). Of the 9 retained predictors, 3 were gender-related. The model was well calibrated and exhibited modest discrimination (area under the curve = 0.66). Conclusions Our female-specific risk model was developed and internally validated in a cohort of young female patients hospitalized with AMI and can be used to predict risk of readmission. Whereas clinical factors were the strongest predictors, the model included several gender-related variables (ie, perceived physical health, depression, income level). However, discrimination was modest, indicating that other unmeasured factors contribute to variability in hospital readmission risk among younger women