Adhesive contact of model randomly rough rubber surfaces

We study experimentally and theoretically the equilibrium adhesive contact between a smooth glass lens and a rough rubber surface textured with spherical microasperities with controlled height and spatial distributions. Measurements of the real contact area $A$ versus load $P$ are performed under compression by imaging the light transmitted at the microcontacts. $A(P)$ is found to be non-linear and to strongly depend on the standard deviation of the asperity height distribution. Experimental results are discussed in the light of a discrete version of Fuller and Tabor's (FT) original model (\textit{Proceedings of the Royal Society A} \textbf{345} (1975) 327), which allows to take into account the elastic coupling arising from both microasperities interactions and curvature of the glass lens. Our experimental data on microcontact size distributions are well captured by our discrete extended model. We show that the elastic coupling arising from the lens curvature has a significant contribution to the $A(P)$ relationship. Our discrete model also clearly shows that the adhesion-induced effect on $A$ remains significant even for vanishingly small pull-off forces. Last, at the local asperity length scale, our measurements show that the pressure dependence of the microcontacts density can be simply described by the original FT model

Statistical analysis of hyper-spectral data: a non-Gaussian approach

We investigate the statistical modeling of hyper-spectral data. The accurate modeling of experimental data is critical in target detection and classification applications. In fact, having a statistical model that is capable of properly describing data variability leads to the derivation of the best decision strategies together with a reliable assessment of algorithm performance. Most existing classification and target detection algorithms are based on the multivariate Gaussian model which, in many cases, deviates from the true statistical behavior of hyper-spectral data. This motivated us to investigate the capability of non-Gaussian models to represent data variability in each background class. In particular, we refer to models based on elliptically contoured (EC) distributions. We consider multivariate EC-t distribution and two distinct mixture models based on EC distributions. We describe the methodology adopted for the statistical analysis and we propose a technique to automatically estimate the unknown parameters of statistical models. Finally, we discuss the results obtained by analyzing data gathered by the multispectral infrared and visible imaging spectrometer (MIVIS) sensor

On the characterization of materials and masonry walls of historical buildings: Use of optical system to obtain displacement maps in double-flat jack tests

Among the testing techniques aiming at the mechanical characterization of masonry, the double flat-jack testing method is widely adopted to identify the local value of significant parameters needed to perform structural analyses, such as elastic modulus, Poisson’s ratio and compressive strength. The experience gained from many applications has allowed not only to collect experimental data concerning different types of masonry, but also to highlight the difficulty in the interpretation of the results and the limitations of both single and double flat-jack tests. Although the accuracy of the flat-jack technique in detecting strength and deformability behavior of masonry is still debated in the technical literature and practical activities, changes in the testing procedure aiming at ascertaining the validity of the test results have not been formally defined yet. After a brief description of the standard test procedure and its uncertainties, the present paper proposes an upgrade of the test procedure for improving the level of reliability of the test results. In particular, an experimental case study related to a historical brick masonry building located in Italy is presented to point out the additional information necessary to validate the results of the testing process

LA SCELTA DEI MATERIALI PER LE GRANDI OPERE CIVILI: IL NUOVO PONTE SUL TICINO A VIGEVANO

Nella memoria vengono presentate le linee guida che ispirano le moderne strategie nella realizzazione delle grandi opere civili. Per tali opere, gli obiettivi da considerare sono diventati via via più numerosi, talché si rivela ormai quasi indispensabile fare ricorso a materiali e a strategie che possano soddisfare assai bene a molti di tali obiettivi, in modo da poterne considerare poi un numero minore nell’ottimizzazione della soluzione. Anche perché, in effetti, alcuni di questi obiettivi sfuggono a razionali procedure scientifiche. La memoria evidenzia come sia da favorire l'impiego dei nuovi calcestruzzi (HPC, HSC, SCC), per la realizzazione delle opere in calcestruzzo armato sulla base di ragioni oggettive, le quali peraltro fanno soddisfare alla necessità di cui sopra si è detto. Emblematico, sotto questo riguardo, è il caso dei ponti stradali per le quali è essenziale una corretta progettazione a garanzia di un esercizio sicuro. A tal proposito, la memoria presenta, come caso studio, il progetto definitivo del nuovo ponte sul Ticino a Vigevano. Le valutazioni di LCC, eseguite con riferimento alla scelta dei materiali, adottate nel progetto definitivo del ponte, permettono di evidenziare come la scelta di materiali più durevoli e performanti, consenta di meglio salvaguardare la vita umana, con l’assurdo che le scelte che consentono di salvare più vite umane sono anche le meno costose per la collettività

Remineralization strategies in oral hygiene: A position paper of italian society of oral hygiene sciences-S.I.S.I.O. working group

Background/Objective: The clinical conditions that lead to an alteration of the enamel structure are numerous. The diet high in sugars and acidifying substances, psychological stress that triggers parafunctional behaviors, the reduced intake of fiber-rich foods or alkalizing substances, together with other factors, contribute to demineralization of the tooth enamel. Dental mineralizing products on the current market are distinguished according to the dosage form, the active ingredient, the release technology, clinical indications and patient choice. Currently, it is necessary to propose to oral health professionals a guide to orient themselves in this chaotic choice, in order to prefer the most effective product for their own clinical target. Methods: Italian Society of Oral Hygiene Sciences-S.I.S.I.O. is one of the leading scientific Italian societies representing those dental hygienists working with high-quality standards and in agreement with scientific evidence: in the last year, the SISIO working group has carried out a study focused on remineralizing agents in dentistry, in order to give an authoritative point of view to indicate a guideline in the decision process of the choice of a remineralizing agent. We will report the results pointed out from the last consensus meeting in 2017. Results: We have reported the good the bad and the ugly have been discussed in a critical discussion of such topic. Conclusion: The SISIO experience has been reported in this position paper with the aim to serve as a useful aid in the daily choice of the clinical steps to perform, when dental professionals need to treat demineralized teeth

A phase II randomised trial of 5-fluorouracil with or without interferon alpha-2a in advanced colorectal cancer.

With the association of 5-fluorouracil (5-FU) and alpha-interferon (IFN), objective responses as high as 26 63% have been reported in untreated patients with advanced colorectal cancer. However, grade 3-4 toxicity has also been reported. We have conducted a prospective phase II randomised study comparing 5-FU to 5-FU + IFN, to investigate whether the addition of IFN to a weekly 5-FU regimen devoid of significant toxicity used at our institutions could improve the effectiveness of 5-FU while maintaining acceptable toxicity. Patients with histologically proven advanced colorectal carcinoma were randomised to receive 5-FU 500 mg m-2 intravenous (i.v.) bolus on days 1-5 followed by 5-FU 500 mg m-2 i.v. bolus weekly from day 15, with or without IFN alpha-2a intramuscularly (i.m.) 1.5 mU daily on days 6-12 and 3 mU i.m. daily thereafter. The treatment was administered on an outpatient basis. Response was evaluated every 3 months, and treatment continued until progression or after two consecutive judgements of stable disease. Response rate was the main end point of the study. Of 141 patients eligible, 72 were randomised to 5-FU alone (arm A) and 69 to 5-FU + IFN (arm B). Responses were 9/72 (12.5%) in arm A and 6/69 (8.7%) in arm B; complete responses were three in arm A and two in arm B. Progression-free survival (median 4 months) and survival (median 12 months) were identical in the two arms. Toxicity was almost absent in arm A and moderate in arm B, represented mainly by haematological toxicity (usually leucopenia). In conclusion, overall survival was good in both arms of treatment and toxicity was moderate. While the response rate with 5-FU alone was in accord with the literature data, response to 5-FU + IFN was lower than expected. At least at this dosage and schedule, the association of 5-FU and IFN is no better than 5-FU alone and is of no clinical interest

In vitro testing of estragole in HepG2 cells: Cytokinesis-block micronucleus assay and cell-cycle analysis

The alkenylbenzene estragole (systematic name, 1-allyl-4-methoxybenzene) is a natural component of essential oils from various spices and herbs, including fennel, and it is used as a food and beverage flavouring agent. Estragole has been reported to be hepatocarcinogenic at high doses in rodents. However, in a previous in vitro study, we found that estragole did not exhibit cytotoxic effects after 4 hours of exposure, nor did it induce DNA damage or apoptosis in human HepG2 hepatoblastoma cells. As fennel tea is widely used for symptomatic treatment of spasmodic gastrointestinal conditions in infants, we aimed at further assessing its safety in a different experimental setting. We thus searched for possible cytogenetic effects and interference with cell-cycle progression in the same human hepatoblastoma cell line. Estragole did not show any clastogenic/aneugenic activities in the cytokinesis-block micronucleus assay, and no effects on cell-cycle checkpoints were observed

Mechanical properties of femoral trabecular bone in dogs

BACKGROUND: Studying mechanical properties of canine trabecular bone is important for a better understanding of fracture mechanics or bone disorders and is also needed for numerical simulation of canine femora. No detailed data about elastic moduli and degrees of anisotropy of canine femoral trabecular bone has been published so far, hence the purpose of this study was to measure the elastic modulus of trabecular bone in canine femoral heads by ultrasound testing and to assess whether assuming isotropy of the cancellous bone in femoral heads in dogs is a valid simplification. METHODS: From 8 euthanized dogs, both femora were obtained and cubic specimens were cut from the centre of the femoral head which were oriented along the main pressure and tension trajectories. The specimens were tested using a 100 MHz ultrasound transducer in all three orthogonal directions. The directional elastic moduli of trabecular bone tissue and degrees of anisotropy were calculated. RESULTS: The elastic modulus along principal bone trajectories was found to be 11.2 GPa ± 0.4, 10.5 ± 2.1 GPa and 10.5 ± 1.8 GPa, respectively. The mean density of the specimens was 1.40 ± 0.09 g/cm(3). The degrees of anisotropy revealed a significant inverse relationship with specimen densities. No significant differences were found between the elastic moduli in x, y and z directions, suggesting an effective isotropy of trabecular bone tissue in canine femoral heads. DISCUSSION: This study presents detailed data about elastic moduli of trabecular bone tissue obtained from canine femoral heads. Limitations of the study are the relatively small number of animals investigated and the measurement of whole specimen densities instead of trabecular bone densities which might lead to an underestimation of Young's moduli. Publications on elastic moduli of trabecular bone tissue present results that are similar to our data. CONCLUSION: This study provides data about directional elastic moduli and degrees of anisotropy of canine femoral head trabecular bone and might be useful for biomechanical modeling of proximal canine femora

Testing for allergic disease: Parameters considered and test value

<p>Abstract</p> <p>Background</p> <p>Test results for allergic disease are especially valuable to allergists and family physicians for clinical evaluation, decisions to treat, and to determine needs for referral.</p> <p>Methods</p> <p>This study used a repeated measures design (conjoint analysis) to examine trade offs among clinical parameters that influence the decision of family physicians to use specific IgE blood testing as a diagnostic aid for patients suspected of having allergic rhinitis. Data were extracted from a random sample of 50 family physicians in the Southeastern United States. Physicians evaluated 11 patient profiles containing four clinical parameters: symptom severity (low, medium, high), symptom length (5, 10, 20 years), family history (both parents, mother, neither), and medication use (prescribed antihistamines, nasal spray, over-the-counter medications). Decision to recommend specific IgE testing was elicited as a "yes" or "no" response. Perceived value of specific IgE blood testing was evaluated according to usefulness as a diagnostic tool compared to skin testing, and not testing.</p> <p>Results</p> <p>The highest odds ratios (OR) associated with decisions to test for allergic rhinitis were obtained for symptom severity (OR, 12.11; 95%CI, 7.1–20.7) and length of symptoms (OR, 1.46; 95%CI, 0.96–2.2) with family history having significant influence in the decision. A moderately positive association between testing issues and testing value was revealed (β = 0.624, <it>t </it>= 5.296, <it>p </it>≤ 0.001) with 39% of the variance explained by the regression model.</p> <p>Conclusion</p> <p>The most important parameters considered when testing for allergic rhinitis relate to symptom severity, length of symptoms, and family history. Family physicians recognize that specific IgE blood testing is valuable to their practice.</p