Plasma Electrolytic Oxidation (PEO) layers from silicate/phosphate baths on Ti-6Al-4V for biomedical components: Influence of deposition conditions and surface finishing on dry sliding behaviour

Plasma Electrolytic Oxidation (PEO) layers were produced on Ti-6Al-4V in different conditions, so as to assess the influence of layer structure, current mode, duty cycle and surface finishing on microstructural features and tribological behavior. In DC regime, the double-layer structure (silicate bath followed by phosphate bath) beneficially affected wear resistance. In unipolar pulsed DC (phosphate bath), the wear resistance of single layers improved with increasing duty cycle, due to improved microstructure and adhesion: high duty cycle single layers can be considered an alternative to double-layer deposition. Surface finishing by abrasive blasting with spheroidal glass beads leads to surface roughness decrease and hence to decreased friction and improved wear resistance. The best-performing PEO layers showed promising results in the comparison with reference materials such as CoCrMo (both uncoated and (Ti,Nb)N PVD-coated) and PVD-coated Ti-6Al-4V up to 30 N normal load

Functional Conservation of the Drosophila gooseberry Gene and Its Evolutionary Alleles

The Drosophila Pax gene gooseberry (gsb) is required for development of the larval cuticle and CNS, survival to adulthood, and male fertility. These functions can be rescued in gsb mutants by two gsb evolutionary alleles, gsb-Prd and gsb-Pax3, which express the Drosophila Paired and mouse Pax3 proteins under the control of gooseberry cis-regulatory region. Therefore, both Paired and Pax3 proteins have conserved all the Gsb functions that are required for survival of embryos to fertile adults, despite the divergent primary sequences in their C-terminal halves. As gsb-Prd and gsb-Pax3 uncover a gsb function involved in male fertility, construction of evolutionary alleles may provide a powerful strategy to dissect hitherto unknown gene functions. Our results provide further evidence for the essential role of cis-regulatory regions in the functional diversification of duplicated genes during evolution

The Homeodomain Protein Defective Proventriculus Is Essential for Male Accessory Gland Development to Enhance Fecundity in Drosophila

The Drosophila male accessory gland has functions similar to those of the mammalian prostate gland and the seminal vesicle, and secretes accessory gland proteins into the seminal fluid. Each of the two lobes of the accessory gland is composed of two types of binucleate cell: about 1,000 main cells and 40 secondary cells. A well-known accessory gland protein, sex peptide, is secreted from the main cells and induces female postmating response to increase progeny production, whereas little is known about physiological significance of the secondary cells. The homeodomain transcriptional repressor Defective proventriculus (Dve) is strongly expressed in adult secondary cells, and its mutation resulted in loss of secondary cells, mononucleation of main cells, and reduced size of the accessory gland. dve mutant males had low fecundity despite the presence of sex peptide, and failed to induce the female postmating responses of increased egg laying and reduced sexual receptivity. RNAi-mediated dve knockdown males also had low fecundity with normally binucleate main cells. We provide the first evidence that secondary cells are crucial for male fecundity, and also that Dve activity is required for survival of the secondary cells. These findings provide new insights into a mechanism of fertility/fecundity

Steel components for packaging devices in sliding/rolling contact: Metallurgical failure analysis

This paper presents a case study in sliding/rolling contacts between steel components operating in packaging devices for powder pressing, where the non-conformal contact involving a rotating roller (AISI M2 tool steel) and pins (AISI 440B martensitic stainless steel) led to the formation of macro- and micro-pitting on both mating surfaces. On the basis of metallurgical failure analysis, surface-origin contact fatigue was identified as the main damage mechanism. Microstructural stress raisers such as relatively large carbides, clustered along plastic flow lines, were observed in both steels. A white etching layer (WEL), due to severe sliding/rolling conditions, further enhanced the formation of surface-origin cracks on the roller

Day and Night at the Museum: Intangible Computer Interfaces for Public Exhibitions

Computer technologies have been adopted in many different venues, including public exhibitions and museums, as they can easily support the exchange of natural interactions and provide unimaginable exploration tools of masterpieces and exhibits. This has led many to design and implement a plethora of different technologies for the detection, tracking and action recognition of visitors within a museum. Nonetheless, no single approach has been firmly accepted so far, as it typically suffers from the limitation of adopting separate techniques for detecting, tracking and recognizing the actions of visitors. The contribution of this paper is that of filling this gap: we propose a unifying methodology through which all of the abovementioned services can be handled within a museum. Furthermore, such methodology results being: (a) simple to implement, (b) non-invasive and (c) requiring minimal hardware resources. As significant evidence, we present the experimental results drawn from two relevant implementations: Mercator Atlas Robot exhibited at the Poggi Palace Museum of Bologna and Tortellino X-Perience at the World Expo held in Shanghai. Finally, we indicate how the presented approach can be extended to efficiently support any interaction with several visitors simultaneously

Prediction of perceived astringency induced by phenolic compounds

A method which can be used to estimate perceived astringency due to polyphenolic compounds is presented here. Thirty subjects were selected on the basis of them having similar salivary flows and they were trained to rate the perceived astringency of tannic acid and grape seed extract solutions. A scale of phenolic compound concentrations ranging from 0 to 3.2 g/L was selected in order to obtain an experimental curve describing the perceived intensity of the sensation. The same astringent solutions were added to a mucin solution in conditions resembling those present in the oral cavity. The formation of polyphenol-protein complexes was measured on the basis of the increasing turbidity of the reaction mixture and was expressed in terms of nephelometric turbidity units (NTU). Experimental curves describing NTU vs polyphenol concentration were obtained. Predictive models of astringency intensity vs NTU were produced. The predictive capacity of the models was checked by comparing the measured and predicted intensities of a set of samples prepared at phenolic compound concentration level varying from 0.94 to 2.13 g/L. © 2004 Elsevier Ltd. All rights reserved

Studio del contatto bronzo-acciaio in condizioni di strisciamento nel settore delle macchine automatiche (Bronze-steel sliding contact in packaging applications)

Lo studio condotto \ue8 dedicato a componenti di macchine automatiche per la pressatura di polveri ad uso farmaceutico o alimentare, sottoposti ad un contatto tribologico non conforme di strisciamento in condizioni di lubrificazione limite. Il tribosistema studiato comprende due elementi: punzoni in acciaio da utensili X100CrMoV5 e camme in bronzo all\u2019alluminio G-CuAl11Fe4Ni4. Nella fase iniziale dello studio sono stati identificati i meccanismi di usura prevalenti nel tribosistema reale avvalendosi di tecniche standard di failure analysis, mentre nella seconda fase sono state eseguite prove di strisciamento su scala di laboratorio. Nelle prove tribologiche di laboratorio, il coefficiente di attrito \ue8 risultato indipendente dalle condizioni di trattamento termico del bronzo, mentre si \ue8 rilevata una significativa dipendenza da carico normale e velocit\ue0. L\u2019usura del bronzo \ue8 risulta principalmente influenzata dalla sua capacit\ue0 di incrudimento e/o di formare e stabilizzare uno strato protettivo superficiale a base di ossidi di rame, al variare delle condizioni di trattamento termico e dei parametri operativi del moto