פרסומים

New particle formation (NPF) from gaseous precursors as a significant source of aerosol needs to be better understood to accurately predict the impacts on visibility, climate change, and human health. While ternary nucleation of sulfuric acid, amines/NH3, and water is recognized as a significant driver for NPF, increasing evidence suggests a contribution from methanesulfonic acid (MSA) and amines under certain conditions. Here we report the formation of particles 2.5-10 nm in diameter from the reactions of MSA with methylamine (MA), dimethylamine (DMA), and NH3 at reaction times of 2.3-7.8 s in a flow reactor and compare these particles with those previously reported to be formed from reaction with trimethylamine (TMA). The effects of water vapor and concentrations of gaseous precursors on the particle number concentration and particle size were studied. The presence of water significantly enhances particle formation and growth. Under similar experimental conditions, particle number concentrations decrease in the order MA >> TMA approximate to DMA >> NH3, where NH3 is 2-3 orders of magnitude less efficient than DMA. Quantum chemical calculations of likely intermediate clusters were carried out to provide insights into the role of water and the different capacities of amines/NH3 in particle formation. Both gas-phase basicity and hydrogen-bonding capacity of amines/NH3 contribute to the potential for particles to form and grow. Our results indicate that, although amines typically have concentrations 1-3 orders of magnitude lower than that of NH3 in the atmosphere, they still play an important role in driving NPF.

Microfluidic organ-on-a-chip technology aims to replace animal toxicity testing, but thus far has demonstrated few advantages over traditional methods. Mitochondrial dysfunction plays a critical role in the development of chemical and pharmaceutical toxicity, as well as pluripotency and disease processes. However, current methods to evaluate mitochondrial activity still rely on end-point assays, resulting in limited kinetic and prognostic information. Here, we present a liveron-chip device capable of maintaining human tissue for over a month in vitro under physiological conditions. Mitochondrial respiration was monitored in real time using two-frequency phase modulation of tissue-embedded phosphorescent microprobes. A computer-controlled microfluidic switchboard allowed contiguous electrochemical measurements of glucose and lactate, providing real-time analysis of minute shifts from oxidative phosphorylation to anaerobic glycolysis, an early indication of mitochondrial stress. We quantify the dynamics of cellular adaptation to mitochondrial damage and the resulting redistribution of ATP production during rotenone-induced mitochondrial dysfunction and troglitazone (Rezulin)-induced mitochondrial stress. We show troglitazone shifts metabolic fluxes at concentrations previously regarded as safe, suggesting a mechanism for its observed idiosyncratic effect. Our microfluidic platform reveals the dynamics and strategies of cellular adaptation to mitochondrial damage, a unique advantage of organ-on-chip technology.

Prediction of drug-induced toxicity is complicated by the failure of animal models to extrapolate human response, especially during assessment of repeated dose toxicity for cosmetic or chronic drug treatments. In this work, we present a 3D microreactor capable of maintaining metabolically active HepG2/C3A spheroids for over 28 days in vitro under stable oxygen gradients mimicking the in vivo microenvironment. Mitochondrial respiration was monitored using two-frequency phase modulation of phosphorescent microprobes embedded in the tissue. Phase modulation is focus independent and unaffected by cell death or migration. This sensitive measurement of oxygen dynamics revealed important information on the drug mechanism of action and transient subthreshold effects. Specifically, exposure to antiarrhythmic agent, amiodarone, showed that both respiration and the time to onset of mitochondrial damage were dose dependent showing a TC50 of 425 μm. Analysis showed significant induction of both phospholipidosis and microvesicular steatosis during long-term exposure. Importantly, exposure to widely used analgesic, acetaminophen, caused an immediate, reversible, dose-dependent loss of oxygen uptake followed by a slow, irreversible, dose-independent death, with a TC50 of 12.3 mM. Transient loss of mitochondrial respiration was also detected below the threshold of acetaminophen toxicity. The phenomenon was repeated in HeLa cells that lack CYP2E1 and 3A4, and was blocked by preincubation with ascorbate and TMPD. These results mark the importance of tracing toxicity effects over time, suggesting a NAPQI-independent targeting of mitochondrial complex III might be responsible for acetaminophen toxicity in extrahepatic tissues. © 2015, Springer-Verlag Berlin Heidelberg.

Although past scholarship shows that group inequalities in economic and political power (“Horizontal Inequalities”) correlate with dissent, violence, and civil wars, there is no direct empirical test of the perceptual explanation for this relationship at the individual level. Such explanation is vital to understanding how integration, inclusion in power-sharing agreements, and exclusion from political power filter down to mass publics. Moreover, subjective perceptions of group conditions do not always correspond to objective group realities. We hypothesize subjective perceptions attenuate the effect of objective exclusion on support for violence in ethnically divided societies. Cross-national comparative multilevel analyses of the 2005/6 Afrobarometer dataset (N = 19,278) confirm that subjective perceptions both amplify the effect of exclusion on acceptance of violence and alter the readiness of included groups to dissent. These findings carry implications for research, state-building, and conflict management.

The sustainable supply of natural water available in the water basin feeding the Dead Sea (comprising of Israel, Jordan and the Palestinian Authority) will soon drop below 100 cubic metres (m3) per person per year. This has resulted from upstream diversions that over time have deprived the Dead Sea of more than 90 % of its historical inflow and led to a progressive decline of its water level with detrimental effects on the surrounding environment and infrastructure. We examine four alternatives to stabilise or restore the Dead Sea and evaluate the costs associated with each alternative. We also offer a mechanism to pay for the reclamation alternatives based on a surcharge levied on all upstream diversions (including water consumed by the potash industries). The surcharge rates associated with the four alternatives range between zero and USD 0.10 per m3. © The Author(s) 2016.

This article critically scrutinizes the perceived view that the emergence of non-core dative constructions in Modern Hebrew is due to a Slavic-Yiddish influence. It studies the Biblical and Mishnaic sources, showing that these language strata contain highly similar constructions to the ones in Modern Hebrew. It additionally shows that paral-lel constructions existed in languages spoken in the Jewish communities at the time of the revival, revealing that this linguistic phenomenon is typologically widely attested. We therefore claim that this could be an example of an internalization of the old gram-mar in the new spoken language, enhanced by the fact that similar constructions are reflected in the non-Hebrew native languages of the revival era speakers. These speak-ers, at the same time, imported into their colloquial Hebrew a sub-type of non-core dative—the discursive dative—to which they could not have been exposed through the ancient written texts, since this type of dative construction occurs only in the spo-ken language.

Amplitude noise, which inflicts a random two-qubit term, is one of the main obstacles preventing the implementation of a high-fidelity two-body gate below the fault-tolerance threshold. This noise is difficult to refocus as any refocusing technique could only tackle noise with frequency below the operation rate. Since the two-qubit-gate speed is normally the slowest rate in the system, it constitutes the last bottleneck toward an implementation of a gate below the fault-tolerant threshold. Here we propose to use composite pulses as a dynamical decoupling approach in order to reduce two-qubit-gate noise for trapped-ion systems. This is done by refocusing the building blocks of ultrafast entangling gates, where the amplitude noise is reduced to shot-to-shot noise. We present detailed simulations showing that the fault-tolerance threshold could be achieved using the proposed approach.

Adsorption of organic pollutants by carbon nanotubes (CNTs) in the environment or removal of pollutants during water purification require deep understanding of the impacts of the presence of dissolved organic matter (DOM). DOM is an integral part of environmental systems and plays a key role affecting the behavior of organic pollutants. In this study, the effects of solution chemistry (pH and ionic strength) and the presence of DOM on the removal of atrazine and lamotrigine by single-walled CNTs (SWCNTs) was investigated. The solubility of atrazine slightly decreased (∼5%) in the presence of DOM, whereas that of lamotrigine was significantly enhanced (by up to ∼70%). Simultaneous introduction of DOM and pollutant resulted in suppression of removal of both atrazine and lamotrigine, which was attributed to DOM-pollutant competition or blockage of adsorption sites by DOM. However the decrease in removal of lamotrigine was also a result of its complexation with DOM. Pre-introduction of DOM significantly reduced pollutant adsorption by the SWCNTs, whereas introduction of DOM after the pollutant resulted in the release of adsorbed atrazine and lamotrigine from the SWCNTs. These data imply that DOM exhibits higher affinity for the adsorption sites than the triazine-based pollutants. In the absence of DOM atrazine was a more effective competitor than lamotrigine for adsorption sites in SWCNTs. However, competition between pollutants in the presence of DOM revealed lamotrigine as the better competitor. Our findings help unravel the complex DOM–organic pollutant–CNT system and will aid in CNT-implementation in water-purification technologies.

This essay is a first attempt to trace the evolution of biographical accounts of Appayya Dīkṣita from the sixteenth century onward, with special attention to their continuities and changes. It explores what these rich materials teach us about Appayya Dīkṣita and his times, and what lessons they offer about the changing historical sensibilities in South India during the transition to the colonial and postcolonial eras. I tentatively identify two important junctures in the development of these materials: one that took place in the first generation to be born after his death, when the idea of him as an avatar of Śiva was introduced, and another at the end of the nineteenth century and the beginning of the twentieth, when many new stories about his encounters with his colleagues and students surfaced. The essay follows a set of themes and tensions that pertain to Appayya Dīkṣita’s social and political affiliations, his sectarian agendas, and the geographic sphere of his activities. These themes and tensions are closely related and prove to be surprisingly resilient, despite the many changes that occurred during the five centuries of recollection that this essay sketches. This overall coherence, I argue, is integral to Appayya Dīkṣita’s sociopolitical context and self-chosen identity.