Production of L-aminoacylase by fermentation of Pseudomonas sp. BA2

The growth and enzymatic production of Pseudomonas sp. BA2 a new L -aminoacylase-producing microorganism, were studied in a bench-top fermenter. Multiple fermentations were carried out in order to determine the optical pH and temperature values. The influence of the substrate concentration on both growth and L aminoacylase activity was also investigated. The maximum growth rate and the greatest yield of enzyme were obtained when the fermentation was carried out at pH 7·5, 25°C and DOT ≥ 50%. N-Acetyl-DL -alanine, at a concentration 20 g dm^?3, was used as the sole carbon and nitrogen source. The fermentation process provided a maximum biomass concentration of 3·36 g dry weight dm^?3. The highest L -aminoacylase production (11429 U g^?1 dry weight) was obtained after 39 h of cultivation. The results were a significant improvement over those previously reported.     

Impact of alloying duration of an electrodeposited Cu/Sn/Zn metallic stack on properties of Cu2ZnSnS4 absorbers for thin‐film solar cells

The impacts of preheating of an electrodeposited Cu/Sn/Zn (CTZ) stack precursor on structural changes of the CTZ precursor and the impact on structural and electric properties of the finally obtained Cu₂ZnSnS₄ (CZTS) films are discussed in detail. We found that preheating for relatively long durations improved the qualities of CZTS films: these films were composed of large grains and had compact and flat surface morphologies. The best solar cell with efficiency of 8.1% was obtained on the basis of a CZTS film derived from the CTZ precursor preheated for 200 min. The external quantum efficiency response of the cell indicated efficient utilization of photons with relatively long wavelength regions because of its good structural and electronic properties. On the other hand, a short circuit current density–temperature property of one of the best cells in this study suggested that the CZTS film had deep acceptor levels and/or an appreciable energy barrier to the Mo back contact. Moreover, an open circuit voltage–temperature property of the corresponding device showed activation energy of 1.18 eV, indicating preferential occurrence of CdS–CZTS interface recombination. Copyright © 2015 John Wiley & Sons, Ltd.     

Security of industrial sensor network-based remote substations in the context of the Internet of Things

The main objective of remote substations is to provide the central system with sensitive information from critical infrastructures, such as generation, distribution or transmission power systems. Wireless sensor networks have been recently applied in this particular context due to their attractive services and inherent benefits, such as simplicity, reliability and cost savings. However, as the number of control and data acquisition systems that use the Internet infrastructure to connect to substations increases, it is necessary to consider what connectivity model the sensor infrastructure should follow: either completely isolated from the Internet or integrated with it as part of the Internet of Things paradigm. This paper therefore addresses this question by providing a thorough analysis of both security requirements and infrastructural requirements corresponding to all those TCP/IP integration strategies that can be applicable to networks with constrained computational resources.     

A Survey of Cryptographic Primitives and Implementations for Hardware-Constrained Sensor Network Nodes

In a wireless sensor network environment, a sensor node is extremely constrained in terms of hardware due to factors such as maximizing lifetime and minimizing physical size and overall cost. Nevertheless, these nodes must be able to run cryptographic operations based on primitives such as hash functions, symmetric encryption and public key cryptography in order to allow the creation of secure services. Our objective in this paper is to survey how the existing research-based and commercial-based sensor nodes are suitable for this purpose, analyzing how the hardware can influence the provision of the primitives and how software implementations tackles the task of implementing instances of those primitives. As a result, it will be possible to evaluate the influence of provision of security in the protocols and applications/scenarios where sensors can be used.

Evaluation of the DTP vaccination technique in infants

OBJECTIVE: To evaluate the techniques of DPT vaccination in the nursing child. DESIGN: An observation study of a crossover type. Evaluation by means of an anonymous survey of those responsible for administering the vaccinations. Statistical analysis using the precise Fisher test. PARTICIPANTS: The thirteen official vaccination centres in Health Areas 11 and 12 in the Community of Valencia. MEASUREMENTS AND MAIN RESULTS: 12 centres (91%) answered the questionnaire. Four of them (41%) used different needles to aspirate the contents of the vial and give the injection to the nursing child. The DPT was always administered in the gluteal region. 33% used needles which were 16 mm long. Prophylactic paracetamol was used in two of the Centres as a matter of course. The Centre's size or length of time in use did not affect the techniques used. CONCLUSIONS: There is no uniformity in the technique of administering the DPT vaccine to the nursing child in the different Vaccination Centres of Areas 11 and 12 in the Community of Valencia. The techniques used for vaccinations often differ from those recommended by groups of experts.     

Response to nitrogen application and interval between harvests in five grasses — 2. Leaf development

Effects of five levels of applied nitrogen on field swards of each of five grasses were studied in the year of sowing, in the first full harvest year and part of the second harvest year. The plots were cut at 4-week intervals during the year of sowing; subsequently 4- and 8-week intervals between cuts were compared.The application of N increased the number of leaf primordia, the number of unemerged leaves, the rates of leaf emergence and death, total green leaf exposure time, the number of green leaves harvested per tiller, leaf blade length, width and weight, and leaf extension rate. The application of N reduced weight per unit area of leaf blade. The increases in size, weight and number of leaf blades appeared to be major reasons for the positive effect of applied N on yield, previously reported. There appeared to be scope for further positive response to applied N beyond 525 kg N ha^–1 yr^–1 in respect of rates of leaf emergence and extension and area per blade. The numbers of primordia and unemerged leaves and the rate of leaf emergence were greater in R v P than in Aberystwyth S.170, with the perennial ryegrasses intermediate. Doubling the interval between harvests reduced the number of leaves which emerged and increased the number which died, increased area and weight per leaf blade except in R v P, and appeared to result in some accumulation of leaf primordia and unemerged leaves. Drought (in 1976) reduced the rates of leaf emergence and extension and area per leaf blade, increased weight per unit area of leaf blade and appeared to result in some accumulation of leaf primordia and unemerged leaves. The length of shoot apex per leaf primordium was relatively constant. Leaf blade size appeared more sensitive in S.170 than in the ryegrasses to interval between harvests, moisture supply and radiation-cum-temperature (but not N supply).