MoS2-Polyaniline Based Flexible Electrochemical Biosensor: Toward pH Monitoring in Human Sweat

Wearable pH sensors for sweat analysis have garnered significant scientific attention for the detection of early signs of many physiological diseases. In this study, a MoS₂-polyaniline (PANI) modified screen-printed carbon electrode (SPCE) is fabricated and used as a sweat biosensor. The exfoliated MoS₂ nanosheets are drop casted over an SPCE and are functionalized by a conducting polymer, polyaniline (PANI) via the electropolymerization technique. The as-fabricated biosensor exhibits high super-Nernstian sensitivity of −70.4 ± 1.7 mV pH⁻¹ in the linear range of pH 4 to 8 of 0.1 m standard phosphate buffer solution (PBS), with outstanding reproducibility. The sensor exhibits excellent selectivity against the common sweat ions including Na⁺, Cl⁻, K⁺, and NH₄⁺ with tremendous long-term stability over 180 min from pH 4 to 6. The enhanced active surface area and better electrical conductivity as a consequence of the synergistic effect between MoS₂ and PANI are correlated with the boosted performance of the as-produced biosensor. The feasibility of the sensor is further examined using an artificial sweat specimen and the successful detection confirms the potential of the biosensor for a real-time noninvasive, skin attachable, and flexible wearable pH sensor.     

The Microbiological Quality of Private Water Supplies

This paper provides a detailed assessment of the microbiological quality of a selection of private water supplies. Samples were taken from 91 supplies and analyzed for total coliforms, faecal coliforms and faecal streptococci. The microbiological quality of the samples was generally poor, with almost 50% of the supplies failing to meet the required standards on at least one occasion. Given the high level of sanitary microbiological failures, there is the possibility that harmful microorganisms could be present and a significant risk to health cannot be discounted.     

The Microbiological Quality of Private Water Supplies

This paper provides a detailed assessment of the microbiological quality of a selection of private water supplies. Samples were taken from 91 supplies and analyzed for total coliforms, faecal coliforms and faecal streptococci. The microbiological quality of the samples was generally poor, with almost 50% of the supplies failing to meet the required standards on at least one occasion. Given the high level of sanitary microbiological failures, there is the possibility that harmful microorganisms could be present and a significant risk to health cannot be discounted.     

Switching characteristics of an optically controlled GaAs-MESFET

The switching characteristics of an optically controlled Metal Semiconductor Field Effect Transistor (MESFET), popularly known as Optical Field Effect Transistor (OPFET), have been derived analytically. The limitations of the existing model have been overcome in the present model. Calculations are being carried out to examine the effect of illumination on the current-voltage characteristics, drain-to-source capacitance (C_dc), internal gate-to-source capacitance (C_gs), drain-to-source resistance (R_ds), the transconductance (g_m), the input RC time constant and the cutoff frequency (f_T) of a GaAs-MESFET. The variations of these parameters with gate length L_g and the doping concentration N_d have also been studied in dark and illuminated conditions. The results of numerical calculations show that there is an overall decrease in the input RC time constant of the device in the illuminated condition arising from the internal gate-to-source capacitance and the transconductance. The results obtained on the basis of the model show a close agreement with the reported experimental findings. The simple model presented here is fairly accurate and can be used as a basic tool for circuit simulation purposes     

Inter-Basin Water Transfers and Drought Management in the Kielder/Derwent System

During the dry years between 1989 and 1994, inter-basin water transfers from the Kielder system augmented flows in the River Derwent, and these flows substituted compensation releases from Derwent reservoir to retain storage for supply and recreational purposes.
The paper discusses the use of the Kielder transfers together with their impact upon (a) flow regime, (b) water quality, and (c) instream ecology of the River Derwent. Also, implications of the increasing use of water transfers in the UK are critically evaluated from the perspective of sustainability.     

The Danube Programme: The Challenge of International River-Basin Management

This paper highlights the key issues which affected the design and implementation of water policy within the first phase of the Environmental Programme for the Danube River Basin. The programme represents one of several regional environmental initiatives in Eastern Europe which were designed to control pollution through the coordinated actions of national governments, international organizations, international financial institutions and non-governmental organizations.
The paper identifies three key controversial findings. Firstly, although the programme has been a valuable tool for the skills and technology transfer which are necessary to enable the Danube states to control water pollution, it has failed to generate the anticipated levels of capital investment or establish itself as a cornerstone of Danube basin management. Secondly, the policy process has been beset by political, economic, social and historical conflicts and power struggles between the participating parties. Thirdly, valuable lessons for the strategic and sustainable management of international river basins can be learned from the operational experiences of the Danube programme.     

Water-Resource Allocation for Recreation, Leisure and Amenity

The paper (a) assesses the social and economic demands for water-related recreational, leisure and amenity facilities, (b) reviews the ways in which these demands are currently satisfied for lakes, reservoirs, rivers and canals, and (c) identifies possible future trends. The significant degree of interaction with other uses of water is also discussed.     

Aquifer Recharge: An Operational Drought-Management Strategy in North London

The North London Artificial Recharge scheme, which comprises thirty-seven wells and boreholes, is designed to boost resources during a drought. All sources discharge groundwater either to the Lee Valley reservoirs or the New River during the abstraction, which avoids the need for expensive on-site water treatment and significantly enhances the cost effectiveness of the scheme. Fully treated drinking water provides the source of gravity-fed artificial-recharge water, via the normal distribution system.
This paper describes the strategy which was introduced in 1997, in response to a deteriorating water-resources situation. Abstraction occurred over a period of four months prior to the onset of autumnal winter rainfall. Daily abstraction rates peaked at 150 Ml/d, and a total of about 10 700 Ml were withdrawn.