Pristine silver nanoparticles (AgNPs) are not chemically stable in the environment and react strongly with inorganic ligands such as sulfide and chloride once the silver is oxidized. Understanding the environmental transformations of AgNPs in the presence of specific inorganic ligands is crucial to determining their fate and toxicity in the environment. Chloride (Cl(-)) is a ubiquitous ligand with a strong affinity for oxidized silver and is often present in natural waters and in bacterial growth media. Though chloride can strongly affect toxicity results for AgNPs, their interaction is rarely considered and is challenging to study because of the numerous soluble and solid Ag-Cl species that can form depending on the Cl/Ag ratio. Consequently, little is known about the stability and dissolution kinetics of AgNPs in the presence of chloride ions. Our study focuses on the dissolution behavior of AgNPs in chloride-containing systems and also investigates the effect of chloride on the growth inhibition of E.coli (ATCC strain 33876) caused by Ag toxicity. Our results suggest that the kinetics of dissolution are strongly dependent on the Cl/Ag ratio and can be interpreted using the thermodynamically expected speciation of Ag in the presence of chloride. We also show that the toxicity of AgNPs to E.coli at various Cl(-) concentrations is governed by the amount of dissolved AgCl(x)((x-1)-) species suggesting an ion effect rather than a nanoparticle effect.

Power-intensive processes can lower operating expenses when adjusting production planning according to time-dependent electricity pricing schemes. In this paper, we describe a deterministic MILP model that allows optimal production planning for continuous powerintensive processes. We emphasize the systematic modeling of operational transitions, that result from switching the operating modes of the plant equipment, with logic constraints. We prove properties on the tightness of several logic constraints. For the time horizon of one week and hourly changing electricity prices, we solve an industrial case study on air separation plants, where transitional modes help us capture ramping behavior. We also solve problem instances on cement plants where we show that the appropriate choice of operating modes allows us to obtain practical schedules, while limiting the number of changeovers. Despite the large size of the MILPs, the required solution times are small due to the explicit modeling of transitions.

Combined heat and power (CHP) plants are widely used in industrial applications. In the aftermath of the recession, many of the associated production processes are under-utilized, which challenges the competitiveness of chemical companies. However, under-utilization can be a chance for tighter interaction with the power grid, which is in transition to the so-called smart grid, if the CHP plant can dynamically react to time-sensitive electricity prices.In this paper, we describe a generalized mode model on a component basis that addresses the operational optimization of industrial CHP plants. The mode formulation tracks the state of each plant component in a detailed manner and can account for different operating modes, e.g. fuel-switching for boilers and supplementary firing for gas turbines, and transitional behavior. Transitional behavior such as warm and cold start-ups, shutdowns and pre-computed start-up trajectories is modeled with modes as well. The feasible region of operation for each component is described based on input-output relationships that are thermodynamically sound, such as the Willans line for steam turbines. Furthermore, we emphasize the use of mathematically efficient logic constraints that allow solving the large-scale models fast.

Background:Intraoperative cytology is an important diagnostic modality improving on the accuracy of the frozen sections. It has shown to play an important role especially in the intraoperative diagnosis of central nervous system tumors.Aim:To study the diagnostic accuracy of squash preparation and frozen section (FS) in the intraoperative diagnosis of central nervous system (CNS) tumors.Materials and Methods:This prospective study of 114 patients with CNS tumors was conducted over a period of 18 months (September 2004 to February 2006). The cytological preparations were stained by the quick Papanicolaou method. The squash interpretation and FS diagnosis were later compared with the paraffin section diagnosis.Results:Of the 114 patients, cytological diagnosis was offered in 96 cases. Eighteen nonneoplastic or noncontributory cases were excluded. Using hematoxylin and eosin-stained histopathology sections as the gold standard, the diagnostic accuracy of cytology was 88.5% (85/96) and the accuracy on FS diagnosis was 90.6% (87/96). Among these cases, gliomas formed the largest category of tumors (55.2%). The cytological accuracy in this group was 84.9% (45/53) and the comparative FS figure was 86.8% (46/53). In cases where the smear and the FS diagnosis did not match, the latter opinion was offered.Conclusions:Squash preparation is a reliable, rapid and easy method and can be used as a complement to FS in the intraoperative diagnosis of CNS tumors.

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With the advent of deregulation in electricity markets and an increasing share of intermittent power generation sources, time-sensitive electricity prices (as part of so-called demand-side management in the smart grid) offer potential economical incentives for large industrial customers. These incentives have to be analyzed from two perspectives. First, on an operational level, aligning the production planning with the electricity price signal might be advantageous, if the plant has enough flexibility to do so. Second, on a strategic level, investments in retrofits of existing plants, such as installing additional equipment, upgrading existing equipment, or increasing product storage capacity, facilitate cost savings on the operational level by increasing operational flexibility.In part I of this paper, we propose an MILP formulation that integrates the operational and strategic decision-making for continuous power-intensive processes under time-sensitive electricity prices. We demonstrate the trade-off between capital and operating expenditures with an industrial case study for an air separation plant. Furthermore, we compare the insights obtained from a model that assumes deterministic demand with those obtained from a stochastic demand model. The value of the stochastic solution (VSS) is discussed, which can be significant in cases with an unclear setup, such as medium baseline product demand and growth rate, large variance or skewed demand distributions. While the resulting optimization models are very large-scale, they can mostly be solved within up to three days of computational time. A decomposition algorithm that allows solving the problems faster is described in part II of the paper.

While the extant literature has examined the influence of controlling and non-controlling principals on the internationalization decisions of emerging market firms, heterogeneity among non-controlling principals is largely ignored. The risk characteristics of different groups of owners, shaped by their institutional environments, could contribute to the differences in their preferences for firm internationalization. In this paper, we draw insights from institutional theory and behavioral risk perspective to examine the risk propensities and risk perceptions of various non-controlling principals, such as pressure-resistant (FIIs and mutual funds) and pressuresensitive (banks, insurance companies and lending institutions) institutional investors. Empirical results from a sample of 2364 unique Indian firms during the 2005-2014 time-period show that, after controlling for firm-level resources and capabilities identified in prior literature, the ownership share of different types of institutional investors is associated with firms' international investments differently. While pressure-sensitive institutional investors, such as banks and insurance companies, are not supportive of foreign investments by firms, pressure-resistant institutional investors, such as FIIs and mutual funds, are supportive of this strategic decision. Furthermore, our results show that the family ownership in a firm (measured in terms of family shareholding) further lowers the preference of pressure sensitive institutional investors for internationalization, whereas family ownership positively moderates the pressure resistant investors towards internationalization.

Aims:This study was taken up with the aim to investigate the pattern of supraclavicular lymphadenopathy among patients presenting to our tertiary care institution, evaluate the diagnostic efficacy of fine needle aspiration cytology (FNAC), and analyze the diagnostic pitfalls.Materials and Methods:A total of 215 patients were subjected to FNAC of supraclavicular lymph nodes over a three-year period (August 2006 to July 2009). Since in 18 patients as either the aspirate was inadequate or the opinion was equivocal, we analyzed the remaining 197 cases.Results:Malignant pathology accounted for 79.7% (157/197) of the cases. These were mostly cases of metastatic squamous cell carcinoma (79/197, 40.1%), adenocarcinoma (47/197, 23.9%), small cell carcinoma (12/197, 6.1%) and lymphoma (10/197, 5%). There were 28 (14.2%) cases of tuberculosis. Out of these 197 patients, 92 patients were biopsied. The opinion based on FNAC was erroneous in 6 cases but corroborated with the final histopathology findings in the remaining 86 cases.Conclusion:FNAC is an excellent first line of investigation; and when used with a proper combination of experience and diligence, it can greatly reduce the number of errors.