Metabolic Role of Sulfates and Sulfides Producing Bacteria in Pollution of Waters

Cytochrome transport particles from Nitrobacter catalyzed nitrite, ascorbate as well as NADH oxidation with concomitant phosphate esterification yielding P/0 ratios of 1.0, 0.6 and 2.0 respectively. Phosphorylation coupled to nitrite oxidation was not effected by rotenone, amytal or antimycin while 50 and 70% inhibition of the NADH-linked phosphorylation was observed in the presence of HOQNO and rotenone respectively. Cell-free extracts from Nitrobacter also catalyzed an energy-dependent reduction of NAD+ by nitrite. The reduction of cytochrome c by NŌ2 was energy-dependent which involved the reversal of electrons from cytochrome a1. The subsequent energy-linked reduction of the flavoproteins and pyridine nucleotides occurred concomitantly with the oxidation of cytochrome c. The process of energy-linked reversal of electron transfer in Nitrobacter was markedly sensitive to all the inhibitors and uncouplers. The reduction of NAD+ by thiosulfate in T. neapolitanus was an energy-linked process and involved the reversal of electrons from ferrocytochrome c mediated by flavoproteins. Cell-free extracts also catalyzed the reduction of NAD+ by sultie at the expense of ATP and involved the participation of the flavoprotein-pyridine nucleotide segment of the respiratory chain. The NADH oxidation by T. neapolitanus was mediated by the flavoprotein and cytochrome systems and this process also appeared to be coupled with energy-generation. The energy-dependent metabolism of sulfate producing bacteria and nitrite oxidizing bacteria was found to be very markedly sensitive to extremely low quantities of chloro, bromo or nitre-substituted phenols. Investigations which were conducted to assess the importance of these organisms in natural environments seem to be rather important in designing control measures for the control of biological production of sulfur or nitrogen compounds or acidity in acid-mine streams or spoil bank

CSF oligoclonal bands in multiple sclerosis

Objective: To study the significance of oligoclonal bands in neurological disorders, specifically in Multiple Sclerosis (MS). Methods: The study was designed to assess the sensitivity and specificity of the test methodology of CSF electrophoresis by performing the retrospective analysis of CSF samples sent for oligoclonal bands (OCB). A total of 603 samples were received by the Clinical Laboratories, Department of Pathology of The Aga Khan University, during a period of 54 months (January 1993-June 1997). All of these samples were analyzed by performing CSF protein electrophoresis. One hundred thirty three out of 603 samples showed evidence of OCB. Out of these, 24 patients were registered with Section of Neurology, Department of Medicine, The Aga Khan University Hospital. These 24 patients were finally selected for analysis. Relevant clinical details such as age, sex and clinical presentations were recorded. Results: Fifteen (62%) out of 24 patients with positive OCB were diagnosed as cases of MS. Four (17%) patients were diagnosed to have subacute sclerosing panencephalitis (SSPE). Five (21%) patients were having other inflammatory neurological disorders. Conclusion: The overall relative sensitivity and specificity for multiple sclerosis were found to be 100% and 62.5% respectively. Lack of specificity was attributed to the fact that OCB were positive in other neurological disorders as well

Performance of grid-connected solar photovoltaic systems with single-tuned and double-tuned harmonic passive filters

The generated solar photovoltaic power can be stand-alone or grid-connected. In both systems, power quality issues arise and can affect the network. The harmonic distortions can affect the system significantly if they are not mitigated. This paper presents the performance of grid-connected solar photovoltaic systems with single-tuned and double-tuned filters for harmonics mitigation. The design aspects of each filter are presented and discussed. The simulation results are analyzed and validated using ETAP software

Agent-based simulations on Catalan interprovincial migrations

This work contemplates the phenomenon of migration related to economic reasons. Firstly, the foundations of a mathematical model are laid down, which have key departure points that mold the approach for doing the rest of the thesis. Secondly, a statistical model on the probability of Catalan interprovincial migrations is displayed. Finally, a NetLogo model is used to simulate the Catalan interprovincial migrations, more specifically, return migrations throughout the period 2008-2020.Este trabajo contempla el fenómeno de la migración relacionado con motivos económicos. En primer lugar, se establecen las bases de un modelo matemático, que tiene puntos de partida claves que moldearon el enfoque para hacer el resto de la tesis. En segundo lugar, se muestra un modelo estadístico sobre la probabilidad de las migraciones interprovinciales catalanas. Finalmente, se utiliza un modelo hecho con NetLogo para simular las migraciones interprovinciales catalanas, más concretamente, las migraciones de retorno a lo largo del periodo 2008-2020

Optimal network reconfiguration in active distribution networks with soft open points and distributed generation

Copyright © 2019 by the authors. In this study, we allocated soft open points (SOPs) and distributed generation (DG) units simultaneously with and without network reconfiguration (NR), and investigate the contribution of SOP losses to the total active losses, as well as the effect of increasing the number of SOPs connected to distribution systems under different loading conditions. A recent meta-heuristic optimization algorithm called the discrete-continuous hyper-spherical search algorithm is used to solve the mixed-integer nonlinear problem of SOPs and DGs allocation, along with new NR methodology to obtain radial configurations in an efficient manner without the possibility of getting trapped in local minima. Further, multi-scenario studies are conducted on an IEEE 33-node balanced benchmark distribution system and an 83-node balanced distribution system from a power company in Taiwan. The contributions of SOP losses to the total active losses, as well as the effect of increasing the number of SOPs connected to the system, are investigated to determine the real benefits gained from their allocation. It was clear from the results obtained that simultaneous NR, SOP, and DG allocation into a distribution system creates a hybrid configuration that merges the benefits offered by radial distribution systems and mitigates drawbacks related to losses, power quality, and voltage violations, while offering a far more efficient and optimal network operation. Also, it was found that the contribution of the internal loss of SOPs to the total loss for different numbers of installed SOPs is not dependent on the number of SOPs and that loss minimization is not always guaranteed by installing more SOPs or DGs along with NR. One of the findings of the paper demonstrates that NR with optimizing tie-lines could reduce active losses considerably. The results obtained also validate, with proper justifications, that SOPs installed for the management of constraints in LV feeders could further reduce losses and efficiently address issues related to voltage violations and network losses

Big data optimization in electric power systems: a review

There are different definitions of big data, and among them, the most common definition refers to three or five characteristics, called volume, velocity, variety, value, and veracity from (Laney (2001)). Volume could include Tera Byte, Peta Byte, Exa Byte, and Zetta Byte. Velocity describes how fast the data are retrieved and processed ‘‘Batch or streaming”. Variety describes structured, semi-structured, and unstructured data (Laney, 2001, Zikopoulos and Eaton, 2011). Veracity explains the integrity and disorderliness of data, while value refers to how good is the “value” we derive from analyzing data? (Zicari et al., 2016). Electrical power systems are networks of components arrayed to supply, transfer, and use electric power. In power system since models are used to predict and characterize operations. However, there is a necessity for powerful optimization algorithms for information processing to learn models as the size increase of data is becoming a global problem to solve large-scale optimization problems. Any optimization problem includes a real function to be maximized or minimized by systematically determination of input values from an allowed set of values. Richness and quantity of large data sets provide the potential to enhance statistical learning performance but require smart models that use the latent low-dimensional structure for effective 2 data separation. This chapter reviews the most recent scientific articles related to large and big data optimization in power systems. Optimization issues such as logistics in power systems and techniques including nonsmooth, nonconvex, and unconstrained large-scale optimization are presented. After a brief review of big data, scientometric analysis has been applied using keywords of “big data” and “power system.” Besides, keywords analysis, network visualization, journal map, and bibliographic coupling analysis have been done to draw a path on big data works in power system problems. Also, the most common useful techniques in large-scale optimization in power system have been reviewed. At the end of this chapter, metaheuristic techniques in big data optimization are reviewed to show that many efforts have been involved in big data optimization in power system and systematically highlight some perspectives on big data optimization

Hepatitis C virus cell-cell transmission and resistance to direct-acting antiviral agents

Hepatitis C virus (HCV) is transmitted between hepatocytes via classical cell entry but also uses direct cell-cell transfer to infect neighboring hepatocytes. Viral cell-cell transmission has been shown to play an important role in viral persistence allowing evasion from neutralizing antibodies. In contrast, the role of HCV cell-cell transmission for antiviral resistance is unknown. Aiming to address this question we investigated the phenotype of HCV strains exhibiting resistance to direct-acting antivirals (DAAs) in state-of-the-art model systems for cell-cell transmission and spread. Using HCV genotype 2 as a model virus, we show that cell-cell transmission is the main route of viral spread of DAA-resistant HCV. Cell-cell transmission of DAA-resistant viruses results in viral persistence and thus hampers viral eradication. We also show that blocking cell-cell transmission using host-targeting entry inhibitors (HTEIs) was highly effective in inhibiting viral dissemination of resistant genotype 2 viruses. Combining HTEIs with DAAs prevented antiviral resistance and led to rapid elimination of the virus in cell culture model. In conclusion, our work provides evidence that cell-cell transmission plays an important role in dissemination and maintenance of resistant variants in cell culture models. Blocking virus cell-cell transmission prevents emergence of drug resistance in persistent viral infection including resistance to HCV DAAs

Direct electrical stimulation enhances osteogenesis by inducing Bmp2 and Spp1 expressions from macrophages and preosteoblasts

The capability of electrical stimulation (ES) in promoting bone regeneration has already been addressed in clinical studies. However, its mechanism is still being investigated and discussed. This study aims to investigate the responses of macrophages (J774A.1) and preosteoblasts (MC3T3-E1) to ES and the faradic by-products from ES. It is found that pH of the culture media was not significantly changed, whereas the average hydrogen peroxide concentration was increased by 3.6 and 5.4 µM after 1 and 2 hr of ES, respectively. The upregulation of Bmp2 and Spp1 messenger RNAs was observed after 3 days of stimulation, which is consistent among two cell types. It is also found that Spp1 expression of macrophages was partially enhanced by faradic by-products. Osteogenic differentiation of preosteoblasts was not observed during the early stage of ES as the level of Runx2 expression remains unchanged. However, cell proliferation was impaired by the excessive current density from the electrodes, and also faradic by-products in the case of macrophages. This study shows that macrophages could respond to ES and potentially contribute to the bone formation alongside preosteoblasts. The upregulation of Bmp2 and Spp1 expressions induced by ES could be one of the mechanisms behind the electrically stimulated osteogenesis.Biotechnology and Biological Sciences Research Council (BBSRC) grant (BB/M013545/1). It also receives funding from The Royal Thai Government scholarship (ST 4729