Theoretical Investigation of NH3-SCR Processes over Zeolites: A Review

The selective catalytic reduction (SCR) of NOx compounds with NH3 is a hot topic in recent years. Among various catalysts, zeolites are proved to be efficient and promising for NH3-SCR, yet the whole processes and intrinsic mechanism are still not well understood due to the structural complexity of zeolites. With the improvement of theoretical chemistry techniques, quantum-chemical calculations are now capable of modeling the structure, acidity, adsorption, and ultimately reaction pathways over zeolites to some extent. In this review, a brief summary of relevant concepts of NH3-SCR is presented. Cluster approaches, embedded techniques, and periodic treatments are described as three main methods. Details of quantum-chemical investigations toward the key issues such as, the structure of active sites, the adsorption of small molecules, and the reaction mechanism of NH3-SCR over zeolites are discussed. Finally, a perspective for future theoretical research is given. 

Sustained inhibition of deacetylases is required for the antitumor activity of the histone deactylase inhibitors panobinostat and vorinostat in models of colorectal cancer

Despite compelling preclinical data in colorectal cancer (CRC), the efficacy of HDACIs has been disappointing in the clinic. The goal of this study was to evaluate the effectiveness of vorinostat and panobinostat in a dose- and exposure-dependent manner in order to better understand the dynamics of drug action and antitumor efficacy. In a standard 72 h drug exposure MTS assay, notable concentration-dependent antiproliferative effects were observed in the IC50 range of 1.2-2.8 μmol/L for vorinostat and 5.1-17.5 nmol/L for panobinostat. However, shorter clinically relevant exposures of 3 or 6 h failed to elicit any significant growth inhibition and in most cases a >24 h exposure to vorinostat or panobinostat was required to induce a sigmoidal dose-response. Similar results were observed in colony formation assays where ≥ 24 h of exposure was required to effectively reduce colony formation. Induction of acetyl-H3, acetyl-H4 and p21 by vorinostat were transient and rapidly reversed within 12 h of drug removal. In contrast, panobinostat-induced acetyl-H3, acetyl-H4, and p21 persisted for 48 h after an initial 3 h exposure. Treatment of HCT116 xenografts with panobinostat induced significant increases in acetyl-H3 and downregulation of thymidylate synthase after treatment. Although HDACIs exert both potent growth inhibition and cytotoxic effects when CRC cells were exposed to drug for ≥ 24 h, these cells demonstrate an inherent ability to survive HDACI concentrations and exposure times that exceed those clinically achievable. Continued efforts to develop novel HDACIs with improved pharmacokinetics/phamacodynamics, enhanced intratumoral delivery and class/isoform-specificity are needed to improve the therapeutic potential of HDACIs and HDACI-based combination regimens in solid tumors.

Mitochondrial Transfer via Tunneling Nanotubes (TNT) is an Important Mechanism by which Mesenchymal Stem Cells Enhance Macrophage Phagocytosis in the in vitro and in vivo Models of ARDS

Mesenchymal stromal cells (MSC) have been reported to improve bacterial clearance in pre-clinical models of Acute Respiratory Distress Syndrome (ARDS) and sepsis. The mechanism of this effect is not fully elucidated yet. The primary objective of this study was to investigate the hypothesis that the anti-microbial effect of MSC in vivo depends on their modulation of macrophage phagocytic activity which occurs through mitochondrial transfer. We established that selective depletion of alveolar macrophages (AM) with intranasal (IN) administration of liposomal clodronate resulted in complete abrogation of MSC anti-microbial effect in the in vivo model of E.coli pneumonia. Furthermore, we showed that MSC administration was associated with enhanced AM phagocytosis in vivo. We showed that direct co-culture of MSC with monocyte-derived macrophages (MDMs) enhanced their phagocytic capacity. By fluorescent imaging and flow cytometry we demonstrated extensive mitochondrial transfer from MSC to macrophages which occurred at least partially through TNT-like structures. We also detected that lung macrophages readily acquire MSC mitochondria in vivo, and macrophages which are positive for MSC mitochondria display more pronounced phagocytic activity. Finally, partial inhibition of mitochondrial transfer through blockage of TNT formation by MSC resulted in failure to improve macrophage bioenergetics and complete abrogation of the MSC effect on macrophage phagocytosis in vitro and the anti-microbial effect of MSC in vivo.

Collectively, this work for the first time demonstrates that mitochondrial transfer from MSC to innate immune cells leads to enhancement in phagocytic activity and reveals an important novel mechanism for the anti-microbial effect of MSC in ARDS.

Minimising harm from alcohol misuse: Challenges to the development of effective policy

Successive substance misuse strategies in Northern Ireland and elsewhere have
been underpinned by the goal of minimising the harm accruing from the use of alcohol and other drugs. However, what it means for a person’s alcohol use to cause harm is an evolving concept. As the understanding of harm changes, the type of evidence needed to estimate the scale of harm and to evaluate the success of a given initiative changes also.
This paper does three things. We first highlight a recent model by Laslett and
colleagues for estimating the harm of one individual’s alcohol use to other individuals, the centrepiece of a report to the Alcohol Education and Research Foundation (AERF) in 2010. This model has been hugely influential in identifying areas where harms from alcohol use accrue and in attempting to quantify those harms (e.g. the cost of injuries inflicted during intoxication). We suggest three ways in which this model could be improved by accounting for: (a) the influence of one individual’s drinking on the drinking behaviour of their peers; (b) the level of use which triggers a given harm; and (c) the degree of time-lag in each of
the domains of harm.
Secondly, we explore specific challenges to developing effective policy on
adolescents’ drinking behaviours, drawing on research which specifically elicits the perspectives of young people on why they drink.
Thirdly, we examine the relative harms of allowing moderate levels of drinking
among mid-adolescents versus promoting zero use up until late adolescence.

Time in Perspective: a visual approach to models of time

Geographical representations of topographical space come in many shapes and are a regular topic of discussion. The depiction of the invisible and maybe even illusory concept of time on the other hand, remains largely unchanged and undisputed. A uniform and arithmetic model of time fits well with the rigid structure of digital data, which might be why it has been widely adopted within HCI. In our proposal, we will present historic and contemporary approaches that offer alternative perspectives on the visual representation of time. Keywords: timeline, chronographics

Dynamic temperature models of a soiless greenhouse

In this paper climate discrete-time dynamic models for the inside air temperature of a soilless greenhouse are identified, using data acquired during two different periods of the year. These models employ data from air temperature and relative humidity.