Fabrication and Characterization of Electrochemical Glucose Sensors

Electrochemical sensors based on the nanostructure of the semiconductor materials are of tremendous interest to be utilized for glucose monitoring. The sensors, based on the nanostructure of the semiconductor materials, are the third generations of the glucose sensors that are fast, sensitive, and cost-effect for glucose monitoring. Glucose sensors based on pure zinc oxide nanorods (NRs) grown on different substrates, such ITO, FTO, and Si/SiO2/Au, were investigated in this research. Silicon nanowire (NW)- based glucose sensors were also studied. First, an enzyme-based glucose sensor was fabricated out of glass/ITO/ZnO NRs/BSA/GOx/nafion membrane. The sensor was tested amperometrically at different glucose concentrations. The device showed a high sensitivity and a lower limit of detection in the order of 10.911 mA/cm2 mM and 0.22 μM, respectively. In addition, the device exhibited a fast and a sharp amperometric time response of ~3 s with different glucose concentrations. The high surface-to-volume ratio provided by the ZnO NRs was investigated by characterizing the sensor with and without the ZnO NRs grown on Si/SiO2/Au substrates. The sensor showed almost a negligible amperometric response to the changes in the glucose concentrations without ZnO NRs. After applying the ZnO NRs, the sensor exhibited a linear response to the glucose concentrations from 1-8 mM. Furthermore, very clear oxidation peaks were observed at the scan rates of 100 and 200 mV/s in the presence of 2 mM of the glucose. The device showed no dependency on different scan rates without applying the ZnO NRs. An enzyme-free glucose sensor was fabricated based on ZnO NRs grown on FTO and modified with Fe2O3. The device showed a high sensitivity and a wide amperometric linear response on the order of 0.052 μA/cm2 and from 100-400 mg/dL, respectively. Reactive ion etching and nanosphere lithography methods were utilized to grow the Si NWs vertically on top of a silicon wafer. The sensor showed a high linearity from 1-9 mM for changes in glucose concentrations. In addition, the high surface-to-volume ratio provided by the Si NWs helped in adsorbing higher concentrations of the enzyme

Productive Development Policies in Trinidad and Tobago: A Critical Review

Even as Trinidad and Tobago seeks productive diversification away from the energy sector, the process underlying the country’s productive development policies (PDP) is in a state of transition from state-directed industrial policy to a newer approach with extensive private-public participation. This study explores the main characteristics of four PDPs in Trinidad and Tobago and reviews them following the related literature (e.g., Rodríguez-Clare, 2005a and 2005b, and Melo and Rodríguez-Clare, 2006). The four PDPs are: a) The process towards the Promotion of Clusters; b) the PDPs for the Tourism industry; c) the classical PDPs for Micro, Small and Medium Enterprises and; d) the Free Trade Zone as a policy designed to compensate for the failure of the State.Industrial policy, Productive development policies, Diversification, Caribbean, Trinidad and Tobago

Efficient learning in ABC algorithms

Approximate Bayesian Computation has been successfully used in population genetics to bypass the calculation of the likelihood. These methods provide accurate estimates of the posterior distribution by comparing the observed dataset to a sample of datasets simulated from the model. Although parallelization is easily achieved, computation times for ensuring a suitable approximation quality of the posterior distribution are still high. To alleviate the computational burden, we propose an adaptive, sequential algorithm that runs faster than other ABC algorithms but maintains accuracy of the approximation. This proposal relies on the sequential Monte Carlo sampler of Del Moral et al. (2012) but is calibrated to reduce the number of simulations from the model. The paper concludes with numerical experiments on a toy example and on a population genetic study of Apis mellifera, where our algorithm was shown to be faster than traditional ABC schemes

Quality Processes in Higher Education in Pakistan and the UK: a Comparative Perspective

In an increasingly competitive global market for higher education, systems and processes for assuring standards and quality remain central to the management and leadership of higher education institutions. Institutional and national reputations for excellence in higher education are dependent on effective quality management systems and confidence in quality management processes. This paper will examine some of the key characteristics of quality processes currently in place in Universities in Pakistan and the UK, focusing on how national policies and systems and institutional quality management frameworks shape institutional understandings of academic quality and standards. Central to this analysis will be a consideration of how concepts of quality assurance and quality enhancement are used and implemented in different national and institutional contexts

Coordinated changes in photosynthetic machinery performance and water relations of the xerophytic shrub Ziziphus lotus (L.) Lam. (Rhamnaceae) following soil drying

Aim of this study was to investigate the effect of water shortage in wild jujube plants, Ziziphus lotus (L.) Lam, and how it is related to its ecological success. All leaf anatomical traits were significantly affected following soil drying. Stressed plants displayed more negative stem water potential (psi(w)) and osmotic potential values of ca. -3.5 and -4.5 MPa, respectively, after 30 d. The relative water content declined although it still maintained high values (>= 75%). The net photosynthetic rate, stomatal conductance, and transpiration rate were significantly inhibited as psi(w) decreased. However, the intrinsic water-use efficiency increased as water deficit was intensified; the difference became significant only after 30 d. As a consequence, the effective quantum yield of PSII photochemistry and the photochemical quenching coefficient significantly decreased although the maximal quantum yield of PSII photochemistry ratio remained statisticaly unchanged. Plants could maintain their water status sufficiently by increasing proline 1.7-fold and sucrose 1.8-fold in their leaves, respectively. The largest accumulation of both solutes may avoid photodamages at cellular level and play a critical role in maintaining osmotic adjustment

Do bank credit rejection and financial education affect financial self-confidence?

Purpose: The purpose of this paper is to examine empirically the determinants of owner manager financial self-confidence. In particular, it estimates the effect of bank credit rejection and financial education (FE) on the financial self-confidence of business owners. Design/methodology/approach: This paper uses data from 2004 and 2008 surveys of 2,500 UK small and medium sized enterprises (SMEs). An ordered probit estimation is used to measure and assess the effect of bank credit rejection and FE variables on financial self-confidence for the two periods. The authors also explore potential differences in self-confidence between males and females. Findings: The results show that outright bank credit rejection reduces financial self-confidence among owner managers whereas partial bank credit rejection is found to help boost confidence prior to the financial crisis. There is strong evidence that FE increases financial self-confidence. Finally, the authors find no association between gender and reported self-confidence in finance. Research limitations/implications: Entrepreneurs and potential entrepreneurs are encouraged to explore financial literacy and knowledge with a view to increasing their financial self-confidence. This will help SMEs to deal with the banks or other finance providers more efficiently. In addition, better application procedures and information on lending criteria may help SMEs to minimize the probability of bank credit rejection. So the current study has implications for professional bodies as well. The study, however, is restricted to sole proprietor and partnership SMEs and in the UK context only. Practical implications: Financial self-confidence has a progressive effect on entrepreneurship and entrepreneurial venture growth. The financial self-confidence of owner managers can support their entrepreneurial capability in starting and operating one or more businesses. As entrepreneurs successfully start and operate their own businesses, they are contributing to economic development through job creation, employment and tax contribution. Originality/value: This paper makes an original contribution in highlighting the usefulness of FE in boosting financial self-confidence among entrepreneurs and potential entrepreneurs. It is also found that the experience of bank credit rejection reduces entrepreneurs’ financial self-confidence

Comparison of first-principles methods to extract magnetic parameters in ultra-thin films: Co/Pt(111)

We compare three distinct computational approaches based on first-principles calculations within density functional theory to explore the magnetic exchange and the Dzyaloshinskii-Moriya interactions (DMI) of a Co monolayer on Pt(111), namely (i) the method of infinitesimal rotations of magnetic moments based on the Korringa-Kohn-Rostoker (KKR) Green function method, (ii) the generalized Bloch theorem applied to spiraling magnetic structures and (iii) supercell calculations with non-collinear magnetic moments, the latter two being based on the full-potential linearized augmented plane wave (FLAPW) method. In particular, we show that the magnetic interaction parameters entering micromagnetic models describing the long-wavelength deviations from the ferromagnetic state might be different from those calculated for fast rotating magnetic structures, as they are obtained by using (necessarily rather small) supercell or large spin-spiral wave-vectors. In the micromagnetic limit, which we motivate to use by an analysis of the Fourier components of the domain-wall profile, we obtain consistent results for the spin stiffness and DMI spiralization using methods (i) and (ii). The calculated spin stiffness and Curie temperature determined by subsequent Monte Carlo simulations are considerably higher than estimated from the bulk properties of Co, a consequence of a significantly increased nearest-neighbor exchange interaction in the Co-monolayer (+50%). The calculated results are carefully compared with the literature

Comparative study of proline accumulation of Some varieties of Durum Wheat (Triticum durum Desf.) under water Stress Conditions.

Proline accumulation, as a marker of resistance to the abiotic constraints, was evaluated on seventeen genotypes of Durum wheat (Triticum Durum Desf) under water stress conditions. An experiment was implemented at INRAA research station located at Baraki, Algiers. The experimental design adopted is that of split plot design with water regime (irrigated and non irrigated treatments) as main plots and varieties as sub plots and three repetitions. Proline accumulation was significantly increased under water stress (p<0.01). There was differences between varieties and their interaction with water regimes (p<0.001) and 04 groups were identified. When plants are subjected to water stress they increase their rate of proline, this enables to improve the capacity of the cell to maintain it turgor pressure at low water potential. Key words: Durum wheat (Triticum durum Desf.), Proline accumulation, resistance, water stress