Search

Purpose To evaluate the long-term effect of subthreshold nanosecond laser (SNL) treatment on progression to late age-related macular degeneration (AMD). Design Observational extension study of a randomized, sham-controlled trial. Participants Two hundred twelve participants with bilateral large drusen. Methods The Laser Intervention in the Early Stages of AMD (LEAD) study was a 36-month trial where participants were randomized to receive SNL or sham treatment in 1 eye at 6-monthly intervals up to 30 months. After the completion of the LEAD study, the 2 largest recruiting sites offered remaining participants an opportunity to enroll in a 24-month observational extension study. This study thus examined all participants from these 2 sites who were enrolled in the LEAD study at baseline, including the additional observational data. Main Outcome Measures Time to develop late AMD, defined on multimodal imaging, between those randomized the SNL or sham treatment. Results Overall, no significant difference was found in the rate of progression over a 60-month period in those randomized to the SNL compared with the sham group (adjusted hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.36–1.09; P = 0.098), similar to the findings at 36 months in the LEAD Study. However, evidence of treatment effect modification continued to emerge based on the coexistence of reticular pseudodrusen (RPD; P = 0.007, adjusted interaction). Namely, progression was slowed significantly with SNL treatment for those without coexistent RPD (adjusted HR, 0.34; 95% CI, 0.16–0.71; P = 0.004), but it was not significantly different for those with RPD (adjusted HR, 1.81; 95% CI, 0.67–4.88; P = 0.239). Conclusions A 24-month observational extension study to the LEAD Study confirmed that SNL treatment did not significantly reduce the overall rate of progression to late AMD in a cohort with intermediate AMD. However, the persistence of a potential beneficial treatment effect in those without coexistent RPD over a longer follow-up duration of an additional 24 months without additional treatment is encouraging. These findings provide further justification for future trials to examine the potential value of SNL treatment for slowing progression in intermediate AMD.

Il presente lavoro ha riguardato la caratterizzazione geometrica, microstrutturale e meccanica di giunti ibridi di spessore pari a 3mm in lega AA5754 ricotta. I giunti sono stati processati a velocità costante di saldatura pari a 3,5 m/min e potenze LASER e MIG variabili. Si è utilizzato un laser a fibra e filo di apporto ER5356. Il materiale base (MB) esibisce microstruttura completamente ricristallizzata con dimensione media dei grani pari a circa 20µm±5 e microdurezza media di 60HV±4. Il cordone dei giunti, analizzato nella sezione trasversale, esibisce la tipica forma a imbuto in cui si individuano due zone: la zona più larga o di corona (CZ) e la zona stretta o zona laser (LZ). La prima zona subisce maggiormente l’azione del processo MIG essendo più prossima alla torcia mentre nella seconda è dominante l’azione del processo LASER. La geometria delle due zone varia al variare dei parametri di processo, in particolare la larghezza della zona di corona è influenzata dal processo MIG mentre la geometria della zona laser è regolata dal valore del rapporto R tra potenza LASER e potenza MIG. In termini di difettosità, la penetrazione del fascio non è completa nei giunti processati alla minima potenza LASER (2500 KW). Inoltre il cordone di tutti i giunti analizzati esibisce porosità crescente all’aumentare della potenza laser. La microstruttura della zona saldata è stata analizzata nella CZ e nella LZ rispettivamente sull’asse del cordone e all’interfaccia. Essa appare di tipo dendritico, caratterizzata da grani colonnari all’interfaccia con il MB e equiassici al centro del cordone. I grani equiassici esibiscono dimensione media superiore rispetto a quella del MB. Nella zona di contatto con il MB si rileva inoltre una stretta zona di grani fini ed equiassici la cui dimensione media dei grani risulta di circa 16µm ±5. Nella sezione trasversale di ogni giunto sono state eseguite prove di micro durezza (HV05/15s). In tutti i casi si registra un minimo sull’asse del giunto e un picco massimo in corrispondenza dell’interfaccia con il MB oltre la quale, i valori di microdurezza tendono al valore medio del MB. Sulla base dello studio effettuato si può concludere che da un punto di vista geometrico i giunti in cui il rapporto R è più prossimo ad 1 sono quelli che presentano una LZ più stretta e snella in cui i grani colonnari si estendono fino a quasi toccarsi nella zona centrale della saldatura. Inoltre all’aumentare della potenza MIG aumenta l’ampiezza della corona. La porosità aumenta invece all’aumentare della potenza laser. I valori minimi di durezza, registrati sull’asse del giunto, sono imputabili alla maggiore dimensione del grano e alla segregazione.

The paper deals with the problem of suitably coordinating the maneuvers of a non-holonomic underwater vehicle and the motion of a supported manipulation system (composed by one or two arms) when the overall system is commanded to execute a given grasping or manipulation task. Results are obtained by merging together some recent ones, relevant to the field of non-holonomic vehicle guidance and maneuvering, with those concerning the coordination of fixed base multiarm manipulation systems.

On the numerical modelling of a milling operation: data recovering and interpolation

Application of Taguchi method to high power diode laser welding of Ti6Al4V

CLASSIFICATION OF SOUNDNESS OF TITANIUM ALLOYS WELD ON THE BASIS OF FUSED ZONE LEVELS FOR IMPERFECTIONS

NEURAL-NETWORK AIDED DOE: AN APPLICATION IN CO2 LASER WELDING OF TI6AL4V

To establish if the indication for different approaches for thyroidectomy and the incision length provided by means of pre-operative assessment of gland volume and size of nodules resulted in safe and effective outcomes and in any notable aesthetic or quality-of-life impact on patients.Ninehundred eightytwo consecutive patients, undergoing total thyroidectomy, were enrolled. The thyroid volume and maximal nodule diameter were measured by means of ultrasounds. Based on ultrasounds findings, patients were divided into three groups: minimally invasive video assisted thyroidectomy (MIVAT), minimally invasive thyroidectomy (MIT) and conventional thyroidectomy (CT) groups. The data concerning the following parameters were collected: operative time, postoperative complications, postoperative pain and cosmetic results.The MIVAT group included 179 patients, MIT group included 592 patients and CT group included 211 patients. Incidence of complications did not differ significantly in each group. In MIVAT and MIT group, the perception of postoperative pain was less intense than CT group. The patients in the MIVAT (7±1.5) and MIT (8±2) groups were more satisfied with the cosmetic results than those in CT group (5±1.3) (p=0.05).The MIT is a technique totally reproducible, and easily convertible to perform surgical procedures in respect of the patient, without additional complications, increased costs, and with better aesthetic results.

Purpose of the study : Promising research suggest that maraviroc (MVC) has favourable clinical outcome in HIV-infected patients (pts). Aim of the study is to assess: durability, safety profile and immunovirological recovery in a large MVC-based cohort. Methods : All HIV pts treated with antiretroviral therapy (ART) containing MVC for at least 6 months (all viruses CCR-5 tropic analyzed by genotypic and phenotypic test) were recruited in an observational multicenter study. Eight Infectious Diseases Centers in Liguria and Piedmont (Italy) collected at baseline and every 3 months demographics, clinical and immunovirological data on a web-based system (by MedinfoDist, University of Genoa). We used SPSS for Pearson Chi square test and for generalized estimating equation (GEE); in this model for longitudinal data and frequency analysis we considered altered: TCD4+ ≤350/mmc, HIVRNA >50 cp/ml, total cholesterol >200 mg/dl, triglycerides >160 mg/dl, transaminase >40 mg/dl, creatinine >1.3 mg/dl and we divided data in 5 time periods: baseline, 1-6, 9-12, 15-24 and 24-45 months. Summary of results : We enrolled 55 pts: 36 (65%) males, median age 49.6 years (yrs) (range [r] 18.2-76.6, IQR 44.5-53.3), 11 (20%) HCVRNA-positive, 4 (7%) HBsAg-positive, 1 both infection. Twenty-four (44%) pts were classified as CDC C stage, median nadir TCD4+ was 219/mmc (r 11-529, IQR 125-317), median duration of ART was 15.3 yrs (r 1.3-27.3, IQR 12-16.8), median duration of treatment with MVC was 23 months (r 6-47, IQR 14-36). At baseline 42 (76%) pts had HIVRNA >50 cp/ml, 11 (20%) HIVRNA ≤50 cp/ml, 2 (4%) pts no data; on treatment at the last examination 53 pts (96%) had HIVRNA ≤50 cp/ml, 2 pts still had HIVRNA >50 cp/ml (CCR5 tropic) and median TCD4+ count was 469/mmc (r 73-1802, IQR 302-592). One pt died and only 2 pts shifted to X4. Chi square test at 9-12 months showed p=0.0001 and the 80% of pts had TCD4+ >350/mmc; at the same observation time 83.3% of pts had HIVRNA ≤50 cp/ml (p=0.0001). About cholesterol, triglycerides, transaminase and creatinine no significative differences were found and the median value showed no changes. Conclusions : In our study a majority of pts treated with ART containing MVC achieved a count of TCD4 >350/mmc and HIVRNA undetectable within 9-12 months. This regimen is a safe, feasible option and in pts with a poor immunological stage, MVC offered a remarkable TCD4+ count gain with limited X4 strains onset. (Published: 11 November 2012) Citation: Abstracts of the Eleventh International Congress on Drug Therapy in HIV Infection Dentone C et al. Journal of the International AIDS Society 2012, 15 (Suppl 4):18265 http://www.jiasociety.org/index.php/jias/article/view/18265 | http://dx.doi.org/10.7448/IAS.15.6.18265

Chronic bacterial osteomyelitis requires long-term antibiotic treatment (at least 6-8 weeks). After in-hospital management, patients are usually discharged and treated in outpatient settings. However, when the aetiology is represented by Gram-negative microorganisms, outpatient treatment could be difficult. Beta-lactam administration by means of an elastomeric infusor may represent an attractive approach. We report two cases of osteomyelitis due to Pseudomonas aeruginosa successfully treated with continuous ceftazidime administration via an elastomeric infusor in outpatient settings. In both cases the patients were free from clinical and laboratory signs of osteomyelitis at the end of treatment and after 12 months follow-up.

World Automation Congress (WAC 2000)

Prosthetic joint infections (PJIs) represent a severe complication in orthopaedics. Coagulase-negative staphylococci (CoNS) and Staphylococcus aureus represent the most frequent cause, but Gram-negatives have also been reported. With a view to describing the aetiology of PJIs diagnosed from January 2005 to September 2007 at S. Corona Hospital in Pietra Ligure, Italy, we conducted retrospective analysis of pathogens isolated from PJIs by means of surgical specimens, needle aspirates or swabs of fistula (3 samples). During the study period 228 PJIs were described and 141 (62%) were microbiologically documented and evaluated. Early and delayed infections represented 45% of episodes, while late infections were observed in 55%. The aetiology was mono-microbial in 84% of cases, and polymicrobial in 16%. CoNS and S. aureus were the most frequently isolated pathogens. In early and delayed infections methicillin resistant CoNS were 30% and 24%, respectively, while in late infections they were 17%. Methicillin-resistant S. aureus was isolated in 13% of early, 22% of delayed and 15% of late infections. Gram-negatives were described in 16% of episodes without differences being found in the three groups. In our report staphylococci represented the most frequent cause of PJIs. Methicillin-resistant strains were more frequently isolated in early and delayed infections, but their frequency in late episodes was not negligible. Polymicrobial infections and Gram-negative infections were also frequent.

Knee arthrodesis is a surgical procedure performed in order to salvage a limb in which the knee joint is compromised in a way to preclude any possibility to re-create a new articulation through a prosthetic replacement. This is especially true in severe periprosthetic septic cases.

Ceramic moulds produce castings with fine details, smooth surface (smoothness 3 mm), and a high degree of dimensional accuracy because the metal contraction can be predicted closely enough to provide castings within excellent tolerances (±0.08 mm on dimensions to 25 mm, ±0.13 mm on dimensions to 75 mm, and more).

Measurement principle, method, procedure, and conditions can heavily affect the measuring uncertainty and in turn the measuring reliability.

This paper deals with the design of embedded FPGA-based control systems for tendon actuated multifingered humanlike robotic hands. A specific example of tendon actuated mechanical design (DIST-Hand) is first considered, as a reference system, without loss of generality; then a general modular approach to the relevant motion control problem features is provided. Finally the most significant implementation issues related to the candidate distributed control architecture are presented.

The paper deals with the problem of suitably coordinating the manoeuvring of a non-holonomic vehicle and the motion of a supported manipulation system (composed by one or two arms) when the overall system is commanded to execute a given grasping or manipulation task. The objective being clearly that of suitably exploiting the extra dof's offered by the vehicle for better accomplishing the assigned task in a cooperative way.

The general characteristics of a dynamic simulator for advanced robotics are discussed. The features of a dynamic simulator, ARS, for advanced robotic applications, currently under development at the University of Genova, are outlined. The flexibility of ARS makes it suitable for the simulation of underwater vehicles and robots. With this objective, simple models of the hydrodynamic effects are presented. >

One of the main problems in robotic research is planning. Different approaches have been considered, ranging from global to local planning. In the authors' approach, the key idea is that of planning movements of redundant robots, which involves both robotic and AI aspects. Pushing is used as a case study and sensorial feedback is considered in order to provide the planner with updated information on the dynamic evolution of the scene and to be able to deal with a priori unknown objects. >

High precision bottom estimation techniques in unmanned underwater vehicles (UUVs) are examined in this paper. Environment sensing is performed by a high-frequency pencil beam profiling sonar mounted on Roby2, a small prototype UUV developed at CNR Istituto Automazione Navale. A multi-hypothesis extended Kalman filter to estimate the bottom slope and its distance from the vehicle is presented. Results obtained by applying this algorithm to real data collected with the vehicle moving in a high-diving pool are discussed. Algorithm improvements based on active sensing and "focusing attention" techniques are suggested.

La piegatura di lamiere mediante l’impiego del laser è una nuova tecnica di lavorazione utilizzata principalmente nelle produzioni di piccole serie e di prototipi. Essa sfrutta gli stress termici indotti dal fascio laser nella lamiera. Tali stress, a raffreddamento avvenuto, si traducono in deformazioni permanenti del materiale costituente la lamiera e danno luogo all’insorgere di elevate tensioni residue all’interno del componente. L’obiettivo di questo lavoro è, pertanto, quello di valutare il campo autotensionale così originato e la resistenza a fatica. Le tensioni residue sono state misurate con il metodo della rosetta forata su due tipologie di provini: un settore circolare e un provino sagomato dello stesso tipo di quelli sottoposti alle prove di fatica. Le autotensioni ottenute risultano elevate e di trazione in prossimità della piega su entrambe le facce dei provini. Le prove di fatica sono state condotte, utilizzando una macchina di fatica monoassiale, con un rapporto di sollecitazione pari a 0.1 e un modello numerico agli elementi finiti è stato implementato per determinare le tensioni effettivamente agenti sulla sezione, considerando la non linearità geometrica e del materiale dei provini.

Laser forming is well known for allowing hard tool-less forming procedures, which produce precise metal sheet products. This is due to the fact that deformations are springback-free since they are induced by thermal variation inside the sheet, which are generated by laser irradiation. The basic mechanism is based on a thermal-induced deformation and it is not yet possible to adequately control it.Nowadays, the generation of complex curved sheet metal parts for rapid prototyping is possible using only curved irradiation, i.e. the irradiated path on the surface is curved. The forming mechanism induced by this irradiation strategy is similar to those of linear irradiation, i.e. the irradiated path on the surface is straight, but their effects are averagely lower.In this paper, the effect of curved irradiation was investigated for AISI 316 and AISI 304 stainless steel sheets by numerical and experimental analysis. The experimental analysis was design according to the Design of Experiments Analysis (DOE) principles. This permits to evaluate the effects of process parameters on the bending angle on the basis of a statistical analysis. In fact, the analysis of variance was performed. It gave the weights of every single studied variables on the deformation process. Thereafter, the levels of the parameters, which gave the largest deformation, were isolated by means of Response Surface Method (RSM).The investigated parameters were the spot diameter, the curvature and the length of irradiation path, the laser power and speed. A CO2 operating in continuous wave regime laser source was used. All the tests were performed and compared on the basis of geometrical and technological parameters. The results were also compared with those of linear irradiation, which were gathered during previous investigations.Moreover, the collected experimental data were interpolated by means of an Artificial Neural Network (ANN), which are well known as universal interpolators.In the view of the exploitation of laser for forming in the mechanical engineering, this investigation provided a better knowledge of the process and demonstrated the effectiveness of DOE for optimal process parameters selection and ANN for experimental data interpolation.Laser forming is well known for allowing hard tool-less forming procedures, which produce precise metal sheet products. This is due to the fact that deformations are springback-free since they are induced by thermal variation inside the sheet, which are generated by laser irradiation. The basic mechanism is based on a thermal-induced deformation and it is not yet possible to adequately control it.Nowadays, the generation of complex curved sheet metal parts for rapid prototyping is possible using only curved irradiation, i.e. the irradiated path on the surface is curved. The forming mechanism induced by this irradiation strategy is similar to those of linear irradiation, i.e. the irradiated path on the surface is straight, but their effects are averagely lower.In this paper, the effect of curved irradiation was investigated for AISI 316 and AISI 304 stainless steel sheets by numerical and experimental analysis. The experimental analysis was design according to the Design of Experiments Analysis (DOE) princ...

According to several authors, laser bending is becoming a valid alternative to dies for manufacturing even complex objects from thin metal sheets. The mechanism is based on thermal induced deformations that are produced by a laser source irradiation on a sheet surface that does not need external forces. Nevertheless, the set up process of parameters is both labour and time consuming. The aim of this paper is to contribute to the management and practical use of this process. Therefore some technological and geometrical parameters, as well as material properties dependence on temperature, have been investigated by analysing and experimenting finite elements. This work reports the results of a largely influential investigation of the above mentioned parameters on thin sheet metal bending. Furthermore, the constructed model can be useful for further developments in laser bending investigation.

This paper provides a description of the functional basis of linear “soft” actuators based on polymer contractility elicited by electrochemical phenomena and driven by external electrical stimuli

Redundancy and concurrency in motor control are basic problems for multi-joint, multi-limb robots. The viscous-electric properties of pseudo-muscular actuators provide an organising factor because they define equilibrium postures that influence body movements as 'postural attractors'. The authors report the state of advancement of a pseudo-muscular actuator which uses polymer gels and describe a computational architecture which naturally exploits the actuator-mechanical structure. The main idea is that the mechanism of generation of synergies of motor commands can be formulated as the internal simulation of passive movement or (passive motion paradigm). They show how this approach can be formulated in connectionist terms as a multiple constraints satisfaction network, driven by a potential function similar to a Hopfield network. They call this model 'motor relaxation network' (or M-net). >

The paper presents the basic ideas and results underlying a learning methodology for the improvement of the quality of motion planned on the basis of the mechanism presented in /1/, for the case of redundant systems. The learning mechanism is based on the use of repeated trials of execution of the given task.Results concerning the conditions for convergence are presented and also discussed on the basis of some simulation examples.

This paper provides a description of the functional basis of linear “soft” actuators based on polymer contractility elicited by electrochemical phenomena and driven by external electrical stimuli.