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Highlights • Proposes a second-order dynamic model to represent an actual So–Nick BESS. • An input–output identification procedure is proposed for parameters identification. • The procedure is based on the Sensitivity theory involving the Lyapunov function. • Experimental tests prove the practical applicability of the proposed methodology. Abstract The aim of this paper is to derive an accurate input/output dynamic equivalent model of a So–Nick Battery Energy Storage System (BESS). For this purpose, an on-line identification methodology has been applied. By this methodology, unknown model parameters are identified in the continuous time domain by solving an optimization problem aimed at minimizing the error between output trajectories of the physical system and its dynamic equivalent model. The methodology is based on the Sensitivity theory involving the Lyapunov function, ensuring the stability of the algorithm. Experimental results are used to validate the proposed approach by adopting the Sodium–Nickel Battery Energy Storage System (BESS) embedded into the experimental Prince Lab of the Polytechnic University of Bari, Italy. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to examine how a coordinated control strategy for managing the active power reserve in isolated microgrids is presented. This methodology can be applied in those microgrids where a specified generator assumes the role of the isochronous generator for the overall system. The derived algorithm evaluates control actions in the on-line environment by solving a constrained dynamic optimization problem aimed at maximizing the overall spinning reserve and, in particular, the reserve offered by the master unit equipped with the isochronous governor controller. The solution of this problem is obtained by adopting the direct Lyapunov theorem applied to the Sensitivity theory, ensuring the algorithm’s stability. Tests performed on the experimental microgrid, which has been built at the Polytechnic University of Bari, demonstrated the ability of the proposed methodology to share the regulation burden among all sources and storage systems, establishing adequate reserve margins of the master unit. [ABSTRACT FROM AUTHOR]

This paper deals with the development of an on-line identification method for deriving simplified dynamic models. The practical applicability of the derived algorithm has been tested on the Capstone C30 microturbine installed at the Polytechnic University of Bari, Italy. For this purpose, a second order model has been identified by adopting the sensitivity theory involving the Lyapunov function giving rise to stable solutions in the on-line environment, renewing model parameters at every changes occurring on the physical system. This characteristic can be fruitfully adopted for implementing actual models in time domain simulators, giving rise to accurate results even if some internal parameters change. In order to investigate on the effectiveness of the proposed methodology in deriving a simplified dynamic model, several simulations and experimental tests were conducted in the Prince Lab of the Polytechnic University of Bari. The good agreement between simulations and laboratory tests confirm the validity and the applicability of the proposed methodology. [ABSTRACT FROM AUTHOR]

The aim of this paper is to define an organized approach for improving the economic, reliable and secure operation of microgrids operating either in the On-grid or in the Off-grid. According to this methodological approach, a microgrid can be operated into five Operating Modes and five Transitions. Proper management of each of them has been examined and implemented on the existing microgrid developed at the Prince — Electrical Energy System Lab of the Polytechnic of Bari. This microgrid can be considered a hard test bed for dynamic stability studies since it is an inertialess system. [ABSTRACT FROM AUTHOR]

This paper proposes a decentralized controller to coordinate the reactive power injections of PV generators in order to contribute to the voltage regulation in distribution networks. The control actions are evaluated in the real time by adopting an optimization methodology involving the sensitivity applied to the Lyapunov function. By this approach it is possible to derive an auto-adaptive algorithm that can be implemented on actual distribution network without implying additional costs for infrastructures. Computer simulations have been performed on a MV distribution system to demonstrate the effectiveness of the proposed control scheme at different operating conditions and to confirm its ability to work in the real time. [ABSTRACT FROM AUTHOR]

This paper proposes a centralized control methodology for optimizing nodal voltages of distribution networks by acting on the reactive power produced by PV-inverters. Control actions are centrally evaluated in real-time by solving a constrained dynamic optimization problem aimed at minimizing the voltage deviation from a reference value. The solution of this problem is obtained by adopting an algorithm operating in the continuous time domain based on a fast artificial dynamic system involving the sensitivity theory. By this approach the controller is able to promptly respond to any change in the system operating point, allowing its adoption in the continuous time domain. However, it must be considered that the injection of the reactive power provided by PV-inverters entails greater conduction and switching losses, causing a reduction in the active power output, thus implying less incomings. As a consequence, these additional operating costs have been analyzed and evaluated in order to establish an economic compensation mechanism able to guarantee fair reimbursement to PV generators engaged in this regulation service. Computer simulations performed on an MV distribution system, demonstrate the effectiveness of the proposed control scheme under different operating conditions, confirming its ability to control the network in real-time. [ABSTRACT FROM AUTHOR]

Abstract: In this paper a novel methodology for evaluating the external equivalent model of a distributed network is presented. The proposed method is based on a non-linear parameter identification process which involves an artificial dynamic system, whose dynamics are explicitly designed to be stable by adopting the Lyapunov theory. This dynamic identification method is competitive with existing reduction methods, since it does not require system linearization or any a priori information about the system under study. Few measurements at boundary nodes are required to obtain the essential information regarding the external system. Even if these measurements are strongly corrupted by noise, the algorithm is quite insensible to it. Due to its ability to be auto-adaptive at any changes in the system operating conditions and to its great speed convergence, the identification procedure can be usefully applied for real-time applications. [Copyright &y& Elsevier]

Abstract: This paper proposes an auto-adaptive controller that enables to suitably manage the reactive power supplied by the inverters of PV units whishing to provide the reactive power ancillary service on the base of standard needs or on a voluntary basis. The derived controller is based on an optimization procedure involving the sensitivity theory in conjunction with the Lyapunov function and provides control laws feeding the inverters of the PV units. The controller promptly minimizes system losses preserving the active power produced by the PV plants against the reactive one. In fact, when the PV modules do not get enough sunlight to generate active power, the proposed procedure forces the PV inverters to provide a reactive power equal to the rated power. On the contrary, in order to preserve the major economic benefits for the investor deriving from the produced active power during the sunlight hours, the method automatically reduces the injection of reactive power. The computer simulations, performed on a distribution system, demonstrate that the controller is capable to control the network in the real-time, mainly due to its ability to be auto-adaptive at any changes in the system operating conditions. [Copyright &y& Elsevier]

Human melanoma cell lines were shown to express ligands for the natural cytotoxicity receptor, NKp46, expressed by natural killer (NK) cells. We aimed to examine the expression of ligands for NKp46 by various primary human melanocytic cells and melanocytic lesions. Sections from primary nevi and melanomas were tested for expression of NKp46 ligands employing chimeric NKp46-Fc for staining. The melanocytes present in the reticular dermis were negative for NKp46 ligands in common nevi; in malignant melanocytic lesions, the deeper melanocytes were focally positive. In dermoepidermal junction of all melanocytic lesions, the melanocytes showed enhanced expression of NKp46 ligands. Melanophages in all lesions were consistently positive for NKp46 ligands. These observations establish the expression of NKp46 ligands by primary-transformed melanocytes. Normal melanocytes did not express ligands to NKp46. Therefore, the results show (i) a correlation between the malignant potential of the lesion and the expression of NKp46 ligands in the reticular dermis, and (ii) enhanced expression of NKp46 ligands in the active proliferation zone (dermoepidermal junction) of nevi and melanomas. Ligands to NKp46 were expressed on the membrane and within the cells. The physiological role of NKp46 ligands in the progression of malignancy within melanocytic lesions should be explored further.Journal of Investigative Dermatology (2008) 128, 972–979. doi:10.1038/sj.jid.5701111; published online 1 November 2007 [ABSTRACT FROM AUTHOR]

• Identify the main design features of different microgrids around the world. • This paper explores the main issues arising from the development of a microgrid. • An attempt to define potential solutions to overcome the main technical issues. • It defines guidelines for practical implementation and operation of microgrids. A microgrid is a small portion of a power distribution system with distributed generators along with energy storage devices and controllable loads which can give rise to a self-sufficient energy system. From the utility grid side, a microgrid is seen as an equivalent generator that is able to seamlessly disconnect and operate autonomously once a fault affects the main grid. The design, installation and operation of such systems lead to dealing with a number of technical and operational challenges including control, protection and infrastructure requirements. To help designers and researchers address these challenges and draw potential recommendations for practical microgrid implementations, in this paper a review of the main design features of existing microgrids is undertaken, also in light of the experience gained during the realization of the Prince Lab microgrid at Polytechnic University of Bari, Italy. The main control functions required to guarantee an economic, reliable and secure operation of a microgrid are also reviewed. Finally, key practical guidelines for monitoring, operation and implementation of microgrids are provided. [ABSTRACT FROM AUTHOR]

To explore the scope and significance of alternate promoter usage and its putative inter-relationship to alternative splicing, we searched expression sequence tags for the 5' region of acetylcholinesterase (ACHE) genes. Three and five novel first exons were identified in human and mouse ACHE genes, respectively. Reverse transcription-PCR and in situ hybridization validated most of the predicted transcripts, and sequence analyses of the corresponding genomic DNA regions suggest evolutionarily conserved promoters for each of the novel exons identified. Distinct tissue specificity and stress-related expression patterns of these exons predict combinatorial complexity with known 3' alternative AChE mRNA transcripts. Unexpectedly one of the 5' exons encodes an extended N terminus in-frame with the known AChE sequence, extending the increased complexity to the protein level. The resultant membrane variant(s), designated N-AChE, is developmentally regulated in human brain neurons and blood mononuclear cells. Alternative promoter usage combined with alternative splicing may thus lead to stress-dependent combinatorial complexity of AChE mRNA transcripts and their protein products. [ABSTRACT FROM AUTHOR]

Background Bevacizumab (BVZ) is an antiangiogenic agent approved by the Food and Drug Administration that is used for the treatment of recurrent glioblastoma. Complications related to impaired healing may adversely affect patients resected for recurrent high-grade glioma (HGG) after treatment with BVZ. Objective To examine the complication rate, outcome, and tumor vasculature in patients resected for recurrent HGG after treatment with BVZ. Methods Data were reviewed retrospectively from patients undergoing surgery for recurrent HGG after treatment with BVZ. Results were compared with a control group of recurrently operated BVZ-naïve HGG. Tumor samples and magnetic resonance imaging scans were analyzed. Results Fifteen patients underwent HGG resection after progression after BVZ. Forty-four BVZ-naïve patients who underwent surgeries for tumor recurrence were included as controls. Median time from BVZ treatment to surgery was 30 days (2–107). Median overall survival from time of tumor diagnosis was 21.0 months (12–83.0), and median survival from post-BVZ surgery was 5.0 months (2.0–19.0), compared with 8.1 months in BVZ-naïve controls measured from time of their last reoperation. Five of the 15 patients survived 6 or more months after post-BVZ surgery. Nine patients developed postsurgical complications requiring intervention. Complication rates for surgery after BVZ treatment were 66.7% compared with 38.6% in the control group ( P = 0.077). We did not see overt changes in histopathology or immunohistochemistry staining; however, tumor vasculature in tumors resected after treatment with BVZ showed a significant decrease in mean vessel density. Conclusions Surgery for recurrent HGG may be feasible in a select group of patients. Mean tumor vessel density may be decreased after treatment with BVZ. [ABSTRACT FROM AUTHOR]