Gold and silver nanoparticle-based colorimetric sensors: New trends and applications

Gold and Silver nanoparticles (AuNPs and AgNPs) are perfect platforms for developing sensing colorimetric devices thanks to their high surface to volume ratio and distinctive optical properties, particularly sensitive to changes in the surrounding environment. These characteristics ensure high sensitivity in colorimetric devices. Au and Ag nanoparticles can be capped with suitable molecules that can act as specific analyte receptors, so highly selective sensors can be obtained. This review aims to highlight the principal strategies developed during the last decade concerning the preparation of Au and Ag nanoparticle-based colorimetric sensors, with particular attention to environmental and health monitoring applications

Current trends in polymer based sensors

This review illustrates various types of polymer and nanocomposite polymeric based sensors used in a wide variety of devices. Moreover, it provides an overview of the trends and challenges in sensor research. As fundamental components of new devices, polymers play an important role in sensing applications. Indeed, polymers offer many advantages for sensor technologies: their manufacturing methods are pretty simple, they are relatively low-cost materials, and they can be functionalized and placed on different substrates. Polymers can participate in sensing mechanisms or act as supports for the sensing units. Another good quality of polymer-based materials is that their chemical structure can be modified to enhance their reactivity, biocompatibility, resistance to degradation, and flexibility

A Low-Cost Approach to the Skin Effect Compensation in Cylindrical Shunts

In this paper the development of a new design solution for high-current shunt resistors is presented, which allows achieving very good accuracy while requiring a simple and low-cost manufacturing process. It is based on a solid cylinder having the voltage measurement circuit which runs through two holes drilled in the cylinder itself. Starting from the well-known expression of the current density in a cylindrical conductor, the frequency response of the shunt is obtained in closed form as a function of the geometric parameters. In turn, the positions of the voltage measurement terminals are chosen by optimizing the frequency response function over a specified range. A shunt prototype has been manufactured and its measurement performance has been evaluated. The experimental results confirm the validity of the approach and highlight the significant improvement with respect to the single-hole cylindrical shunt which has been recently proposed by the authors. The obtained measurement accuracy is noticeable when compared with the ease of manufacturing

Integrating the landscape epidemiology and genetics of RNA viruses: rabies in domestic dogs as a model

Landscape epidemiology and landscape genetics combine advances in molecular techniques, spatial analyses and epidemiological models to generate a more real-world understanding of infectious disease dynamics and provide powerful new tools for the study of RNA viruses. Using dog rabies as a model we have identified how key questions regarding viral spread and persistence can be addressed using a combination of these techniques. In contrast to wildlife rabies, investigations into the landscape epidemiology of domestic dog rabies requires more detailed assessment of the role of humans in disease spread, including the incorporation of anthropogenic landscape features, human movements and socio-cultural factors into spatial models. In particular, identifying and quantifying the influence of anthropogenic features on pathogen spread and measuring the permeability of dispersal barriers are important considerations for planning control strategies, and may differ according to cultural, social and geographical variation across countries or continents. Challenges for dog rabies research include the development of metapopulation models and transmission networks using genetic information to uncover potential source/sink dynamics and identify the main routes of viral dissemination. Information generated from a landscape genetics approach will facilitate spatially strategic control programmes that accommodate for heterogeneities in the landscape and therefore utilise resources in the most cost-effective way. This can include the efficient placement of vaccine barriers, surveillance points and adaptive management for large-scale control programmes

Avaliação longitudinal do efeito do tempo de prática de Pilates solo na cinemática respiratória.

O método Pilates solo tornou-se popular entre o público saudável como uma opção de atividade física por oferecer aulas em grupo e pelo seu baixo custo em relação ao método Pilates com aparelhos. Considerando que todos os exercícios utilizados no método Pilates solo envolvem o controle da respiração é plausível esperar que sua prática possa trazer alterações benéficas à mecânica respiratória. Assim, este trabalho teve por objetivo analisar os efeitos do tempo de prática do Pilates solo na cinemática respiratória. Para isso, foi realizada a análise cinemática tridimensional dos movimentos respiratórios de mulheres saudáveis distribuídas em grupo Pilates (n= 10) e Controle (n=07) durante as manobras respiratórias em volume corrente e capacidade vital. A partir das coordenadas 3D de marcadores posicionados sobre o tórax e o abdome foi calculada a mobilidade do tórax superior, tórax inferior e abdome, assim como a contribuição dos compartimentos para a mobilidade total e a coordenação entre eles durante a avaliação inicial (momento zero) e após 3, 6, 9 e 12 meses de treinamento de Pilates solo. A expansibilidade e a contribuição dos compartimentos foram avaliadas pela amplitude da curva de volume em função do tempo e a coordenação pelo ângulo de fase. A expansibilidade total do tronco e do abdome em volume corrente aumentou no grupo Pilates após três meses de treinamento, mas o abdome reduziu a expansibilidade após nove meses. Após doze meses de treinamento com Pilates solo, a expansibilidade total do tronco e do tórax inferior aumentou em manobra respiratória da capacidade vital. O grupo controle aumentou a expansibilidade do tórax inferior após doze meses tanto em volume corrente quanto em capacidade vital. A contribuição do tórax inferior do grupo Pilates aumentou em ambas as manobras respiratórias após nove e doze meses. O grupo controle também aumentou a contribuição do tórax inferior tanto em volume corrente quanto em capacidade vital após nove e doze meses, mas a contribuição do compartimento abdome reduziu após três e doze meses. A coordenação entre os compartimentos (tórax superior vs. tórax inferior) foi menor no grupo Pilates em relação ao grupo controle durante a manobra de volume corrente no período inicial e após seis meses. Esses resultados sugerem uma maior ação do músculo diafragma em ambos os grupos. Porém, a prática de Pilates solo impactou aumento da expansibilidade total do tronco nas manobras respiratórias, o que não foi observado no grupo controle. De maneira geral, doze meses de Pilates solo aumenta a mobilidade toracoabominal de mulheres saudáveis

Frequency-domain nonlinear modeling approaches for power systems components - A comparison

Harmonic simulations play a key role in studying and predicting the impact of nonlinear devices on the power quality level of distribution grids. A frequency-domain approach allows higher computational efficiency, which has key importance as long as complex networks have to be studied. However, this requires proper frequency-domain behavioral models able to represent the nonlinear voltage-current relationship characterizing these devices. The Frequency Transfer Matrix (FTM) method is one of the most widespread frequency domain modeling approaches for power system applications. However, others suitable techniques have been developed in the last years, in particular the X-parameters approach, which comes from radiofrequency and microwave applications, and the simplified Volterra models under quasi-sinusoidal conditions, that have been specifically tailored for power system devices. In this paper FTM, X-parameters and simplified Volterra approaches are compared in representing the nonlinear voltage-current relationship of a bridge rectifier feeding an ohmic-capacitive dc load. Results show that the X-parameters model reaches good accuracy, which is slightly better than that achieved by the FTM and simplified Volterra models, but with a considerably larger set of coefficients. Simplified Volterra models under quasi-sinusoidal conditions allows an effective trade-off between accuracy and complexity

Antibiotic resistance patterns of faecal indicator organisms and occurrence of Salmonella spp. in wild boar (Sus scrofa scrofa) in Italy.

In order to monitor antibiotic resistance in faecal indicator organisms and evaluate the occurrence of Salmonella spp., faeces from 110 wild boars (Sus scrota scrota), killed during a demographic control program in two different regional parks in Bologna province, were collected from September 2002 to June 2003. A single isolate of Escherichia coli, Enterococcus faecalis and Enterococcus faecium from each sample was tested for antibiotic susceptibility using the agar diffusion method recommended by CLSI (formerly, NCCLS). A total of 110 E. coli, 48 E. faecium and 5 E. faecalis strains were isolated and submitted to antibiotic susceptibility tests. Antibiotic resistance patterns were similar in wild boar populations from both parks. Multiple antibiotic-resistance to ciprofloxacin, rifampin and erythromycin was found with h1gh frequency in Enterococcus spp strains. E. coli isolates showed a low antibiotic resistance level. Two Salmonella arizonae and one Salmonella spp. strains, isolated from wild boars of one park, didn\u27t show any resistance concerning the antibiotics tested

Surveillance for European bat lyssavirus in Swiss bats

Most countries in Western Europe are currently free of rabies in terrestrial mammals. Nevertheless, rabies remains a residual risk to public health due to the natural circulation of bat-specific viruses, such as European bat lyssaviruses (EBLVs). European bat lyssavirus types 1 and 2 (EBLV-1 and EBLV-2) are widely distributed throughout Europe, but little is known of their true prevalence and epidemiology. We report that only three out of 837 brains taken from bats submitted to the Swiss Rabies Centre between 1976 and 2009 were found by immunofluorescence (FAT) to be positive for EBLVs. All three positive cases were in Myotis daubentoni, from 1992, 1993 and 2002. In addition to this passive surveillance, we undertook a targeted survey in 2009, aimed at detecting lyssaviruses in live bats in Switzerland. A total of 237 bats of the species M. daubentoni, Myotis myotis, Eptesicus serotinus and Nyctalus noctula were captured at different sites in western Switzerland. Oropharyngeal swabs and blood from each individual were analysed by RT-PCR and rapid fluorescent focus inhibition test (RFFIT), respectively. RNA corresponding to EBLV-2 was detected from oropharyngeal swabs of a single M. daubentoni bat, but no infectious virus was found. Molecular phylogenetic analysis revealed that the corresponding sequence was closely related to the other EBLV-2 sequences identified in previous rabies isolates from Swiss bats (particularly to that found at Geneva in 2002). Three M. daubentoni bats were found to be seropositive by RFFIT. In conclusion, even though the prevalence is low in Switzerland, continuous management and surveillance are required to assess the potential risk to public healt