Characteristics and usage patterns of older people in a 3D online multi-user virtual environment

3D online multi-user virtual environments (MUVEs) have a lot of potential in supporting older people in their daily lives, yet little research has been conducted to explore how older people engage with this type of technology. This paper aims to investigate the characteristics, user groups and activity patterns (particularly social networks and gift giving behaviour) of older users within a 3D online multi-user virtual environment. Data from approximately 5000 online user profiles of older and younger users from a 3D MUVE, namely IMVU, was collected for analysis. Overall, we identified several distinct patterns of use (e.g. size of social ties, level of reciprocity, etc.) among older users when compared with younger users. We also found that despite the capabilities of 3D MUVEs to provide the users immersion in alternative realities, a feature well embraced by younger users in this study, older users seemed more interested in activities which serve as an extension to their physical life.     

Cost-effective disposable thiourea film modified copper electrode for capacitive immunosensor

Cost-effective disposable electrodes were fabricated from copper clad laminate, usually used for printed circuit board (PCB) in electronic industries, by using dry film photoresist. Electro-oxidation (anodisation) was employed to obtain a good formation of thiourea film on the electrode surface. The affinity binding pair of carcinoembryonic antigen (CEA) and anti-carcinoembryonic antigen (anti-CEA) was used as a model system. Anti-CEA was immobilized on thiourea film via covalent coupling. This modified electrode was incorporated with a capacitive system for CEA analysis. This capacitive immunosensor provided a linear range between 0.01 and 10 ng ml⁻¹ with a detection limit of 10 pg ml⁻¹. When applied to analyze CEA in serum samples, the results agreed well with the enzyme linked fluorescent assay (ELFA) technique (P > 0.05). The proposed strategy for the preparation of disposable modified copper electrode is very cost effective and simple. Moreover, it provides good reproducibility. This technique can easily be applied to immobilize other biological sensing elements for biosensors development.     

Alloy nanowires bar codes based on nondestructive X-ray fluorescence readout

We demonstrate here the ability to generate ternary Co-Ni-Cu alloy nanowires with distinct X-ray fluorescence (XRF) barcode patterns using a one-step template-guided electrodeposition. Such coupling of one-step templated synthesis with a nondestructive XRF readout of the composition patterns greatly simplifies practical applications of barcoded nanomaterials. The new protocol leads to alloy nanowires with broad composition range and hence to an extremely large number of distinguishable XRF signatures. The resulting fluorescence barcodes correlate well with the composition of the metal mixture plating solution, indicating a reproducible plating processes. Factors affecting the coding capacity and identification accuracy are examined, and potential tracking and authenticity applications involving embedding the nanowires within plastics or inks are demonstrated and discussed.     

Aptamer-based potentiometric measurements of proteins using ion-selective microelectrodes

We here report on the first example of an aptamer-based potentiometric sandwich assay of proteins. The measurements are based on CdS quantum dot labels of the secondary aptamer, which were determined with a novel solid-contact Cd2+-selective polymer membrane electrode after dissolution with hydrogen peroxide. The electrode exhibited cadmium ion detection limits of 100 pM in 100 mL samples and of 1 nM in 200 microL microwells, using a calcium-selective electrode as a pseudoreference electrode. As a prototype example, thrombin was measured in 200 microL samples with a lower detection limit of 0.14 nM corresponding to 28 fmol of analyte. The results show great promise for the potentiometric determination of proteins at very low concentrations in microliter samples.     

Production of a polyclonal antibody to the VP26 nucleocapsid protein of white spot syndrome virus (wssv) and its use as a biosensor

White spot syndrome virus (WSSV) is a major cause of high mortality in cultured shrimp all over the world. VP26 is one of the structural proteins of WSSV that is assumed to assist in recognizing its host and assists the viral nucleocapsid to move toward the nucleus of the host cell. The objective of this work was to produce a polyclonal antibody against VP26 and use it as a biosensor. The recombinant VP26 protein (rVP26) was produced in E. coli (BL21), purified and used for immunizing rabbits to obtain a polyclonal antibody. Western blot analysis confirmed that the antiserum had a specific immunoreactivity to the VP26 of WSSV. This VP26 antiserum was immobilized onto a gold electrode for use as the sensing surface to detect WSSV under a flow injection system. The impedance change in the presence of VP26 was monitored in real time. The sensitivity of the biosensor was in the linear range of 160–160000 copies of WSSV, indicating that it is good and sensitive for analysis of WSSV. The specificity of the biosensor was supported by the observation that no impedance change was detected even at high concentrations when using Yellow Head Virus (YHV). This biosensor may be applied to monitor the amount of WSSV in water during shrimp cultivation.     

Effects of gesture-based avatar-mediated communication on brainstorming and negotiation tasks among younger users

This paper reports on a study which investigated the effects of gesture-based avatar-mediated communication on younger users (12–13 years old), in comparison to video-mediated communication. Specifically, we looked at how these technologies were used by school pupils to brainstorm and negotiate ideas in a bullying context. 64 school pupils were divided into two conditions (Skype and AvatarKinect) and were instructed to carry out two tasks (a brainstorming and a negotiation task). Objective task performance, perceived satisfaction and perceived partner’s characteristics were compared. We found no difference in term of perceived satisfaction. AvatarKinect users reported more positive changes in perceptions toward their partner. The results on task performance were ambivalent; Skype users seemed to generate more ideas, whilst AvatarKinect produced better quality ideas. In summary, gesture-based avatar technology appears to be a useful modality to help resolve bullying in schools.     

Age differences in the perception of social presence in the use of 3D virtual world for social interaction

3D virtual worlds are becoming increasingly popular as tool for social interaction, with the potential of augmenting the user’s perception of physical and social presence. Thus, this technology could be of great benefit to older people, providing home-bound older users with access to social, educational and recreational resources. However, so far there have been few studies looking into how older people engage with virtual worlds, as most research in this area focuses on younger users. In this study, an online experiment was conducted with 30 older and 30 younger users to investigate age differences in the perception of presence in the use of virtual worlds for social interaction. Overall, we found that factors such as navigation and prior experience with text messaging tools played a key role in older people’s perception of presence. Both physical and social presence was found to be linked to the quality of social interaction for users of both age groups. In addition, older people displayed proxemic behavior which was more similar to proxemic behavior in the physical world when compared to younger users.     

Interference compensation for thin layer coulometric ion-selective membrane electrodes by the double pulse technique

Ion-selective membranes operated in a thin layer coulometric detection mode have previously been demonstrated to exhibit attractive characteristics in view of realizing sensors without the need for frequent recalibration. In this methodology, the analyte ion is exhaustively removed across an ion-selective membrane by an applied potential, and the resulting current is integrated to yield the coulomb number and hence the amount of analyte originally present in the sample. This exhaustive process, however, places greater demands on the selectivity of the membrane compared to direct potentiometry, since the level of interference will increase as the analyte depletes. We evaluate here a double pulse protocol to reduce the level of interference, in which the sample is electrolyzed once again after the initial coulometric detection pulse. Since the analyte ion is no longer present at significant concentrations during the second pulse, but an interfering ion of high concentration did not appreciably deplete, the second electrolysis step may be used to partially compensate for undesired interference. These processes are here evaluated by numerical simulation for ions of the same charge, demonstrating that the resulting coulomb number may indeed be reduced for systems of limited selectivity. The improvement in operational selectivity relative to uncompensated coulometry is found to be ca. 6-fold. The methodology is successfully demonstrated experimentally with a calcium selective membrane and tetraethylammonium as a model interfering agent, and the observed relative errors after background compensation can be favorably compared to that in direct potentiometry where no sample depletion occurs.     

Exploring the potential of virtual worlds in engaging older people and supporting healthy aging

There is an increasing need to find innovative activities to help the older population maintain a healthy life. Virtual worlds, which can provide social engagement, entertainment and creativity as well as useful information and services for older people might offer a solution to this issue. Although emerging studies have begun to look into the benefits of virtual worlds in healthcare, little has been done in the context of older people. Based on semi-structured interviews and previous research on healthy aging, we identified and described in depth four areas in which virtual worlds could be useful to support older people. In general, it was found that virtual worlds could help empower older people to manage their disabilities, facilitate social engagement, provide mental stimulation and productive activities.