Octopus-like suction cups: from natural to artificial solutions.

Octopus suckers are able to attach to all nonporous surfaces and generate a very strong attachment force. The well-known attachment features of this animal result from the softness of the sucker tissues and the surface morphology of the portion of the sucker that is in contact with objects or substrates. Unlike artificial suction cups, octopus suckers are characterized by a series of radial grooves that increase the area subjected to pressure reduction during attachment. In this study, we constructed artificial suction cups with different surface geometries and tested their attachment performances using a pull-off setup. First, smooth suction cups were obtained for casting; then, sucker surfaces were engraved with a laser cutter. As expected, for all the tested cases, the engraving treatment enhanced the attachment performance of the elastomeric suction cups compared with that of the smooth versions. Moreover, the results indicated that the surface geometry with the best attachment performance was the geometry most similar to octopus sucker morphology. The results obtained in this work can be utilized to design artificial suction cups with higher wet attachment performance.

Dielectric elastomer actuators for octopus inspired suction cups.

Suction cups are often found in nature as attachment strategy in water. Nevertheless, the application of the artificial counterpart is limited by the dimension of the actuators and their usability in wet conditions. A novel design for the development of a suction cup inspired by octopus suckers is presented. The main focus of this research was on the modelling and characterization of the actuation unit, and a first prototype of the suction cup was realized as a proof of concept. The actuation of the suction cup is based on dielectric elastomer actuators. The presented device works in a wet environment, has an integrated actuation system, and is soft. The dimensions of the artificial suction cups are comparable to proximal octopus suckers, and the attachment mechanism is similar to the biological counterpart. The design approach proposed for the actuator allows the definition of the parameters for its development and for obtaining a desired pressure in water. The fabricated actuator is able to produce up to 6 kPa of pressure in water, reaching the maximum pressure in less than 300 ms.

Osmotic actuation modelling for innovative biorobotic solutions inspired by the plant kingdom.

Osmotic-driven plant movements are widely recognized as impressive examples of energy efficiency and low power consumption. These aspects motivate the interest in developing an original biomimetic concept of new actuators based on the osmotic principle exploited by plants. This study takes a preliminary step in this direction, by modelling the dynamic behaviour of two exemplificative yet relevant implementations of an osmotic actuator concept. In more detail, the considered implementations differ from each other in the way actuation energy storage is achieved (through a piston displacement in the former case, through membrane bulging in the latter). The dynamic problem is analytically solved for both cases; scaling laws for the actuation figures of merit (namely characteristic time, maximum force, maximum power, power density, cumulated work and energy density) as a function of model parameters are obtained for the bulging implementation. Starting from such performance indicators, a preliminary dimensioning of the envisaged osmotic actuator is exemplified, based on design targets/constraints (such as characteristic time and/or maximum force). Moreover, model assumptions and limitations are discussed towards effective prototypical development and experimental testing. Nonetheless, this study takes the first step towards the design of new actuators based on the natural osmotic principle, which holds potential for disruptive innovation in many fields, including biorobotics and ICT solutions.

Pattern of care and results of radiotherapy in patients 80 years old and over.

BACKGROUND AND AIMS: Cancer incidence increases with age and several cancer types are observed in older patients, so the need for radiotherapy (RT) in treatment of older patients with cancer is also on the rise. This study's aims to evaluate retrospectively the pattern of care and the feasibility of RT in elderly patients (80 years old and over) treated with different intents, and the impact of RT prescription on survival. MATERIALS AND METHODS: We reviewed 191 patient charts from the years 2005-2007, recording age, intent of treatment, site, and type of RT. Crude and actuarial survival were estimated. RESULTS: One hundred patients were males (M) and 91 females (F); 162 were seen on an outpatient basis, 29 as inpatients. A total of 138 patients were recruited for RT; 113 were treated, 112 completed RT. The ratio to all treated patients was 113/2125 (5.3%). Overall (treated and non-treated) cumulative survival probability was 71% for the first year, 45% for the second and 27% for the third. For treated patients, the cumulative survival probability was 67% for the first year, 43% for the second year and 23% for the third year, while for untreated patients it was 76% for the first year, 47% for the second year and 32% for the third year (Log-rank test: p = 0.23). CONCLUSIONS: RT did not decrease survival in elderly patients.

Esthesioneuroblastoma treated with external radiotherapy. Case report.

Esthesioneuroblastoma is a rare tumour arising from the olfactory epithelium of the nasal vault which frequently invades the cranial base and orbit. Esthesioneuroblastoma has a bimodal age distribution between 11 and 20 years and between 51 and 60 years. Esthesioneuroblastoma accounts for approximately 1-5% of intranasal cancers. The case is reported of a 79-year-old female patient with a Kadish stage C tumour with a one-year history of headache, nasal obstruction, anosmia, rhinorrhoea and epistaxis. Aim of this study is to analyse the natural history, treatment and prognosis of this tumour, based on a review of the literature.

[Multivariate analysis of prognostic factors and survival in patients with "glioblastoma multiforme"]. / Multivariate analysis of prognostic factors and survival inpatients with "glioblastoma multiforme".

PURPOSE: The aim of this study was to evaluate the survival of patients with "glioblastoma multiforme", to analyse the prognostic factors influencing the survival rate and to review recent results in the literature. MATERIALS AND METHODS: Seventy five patients underwent radiation treatment between May 1998 and April 2003. Among the factors under investigation we ascertained that sex, chemotherapy, conformal treatment, surgery, and the choice of the irradiation area (whole brain or only the involved field) did not influence the survival in a statistically significant manner. RESULTS: Whereas age and total dose were the 95% statistically significant variables. Hazard ratio of patients older than 58 years compared to younger patients was 1.69. The death risk was 69% in older than younger patients. A greater irradiation dose improved the survival with an increase of the median survival days. The total dose lower than 6000 cGy caused an increase of 81.8% in the death risk. The median survival from the diagnosis to the death was 14.7 months (446 days) and 1-, 2- and 3- year survival rate was 69.3%, 38.4%, and 14.7% respectively. CONCLUSIONS: The current medical literature and our experience attests that the use of temozolomide improves the survival of these patients.