scholarly journals Special Issue: Application of Photoactive Nanomaterials in Degradation of Pollutants

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2459
Author(s):  
Roberto Comparelli
Keyword(s):  
Gas Phase ◽  
Potential Application ◽  
Organic Pollutant ◽  
Water Disinfection ◽  
Fine Tuning ◽  
Synthetic Approach ◽  
Special Issue ◽  
Photoactive Materials ◽  
Post Synthesis ◽  
Degradation Of Pollutants

Photoactive nanomaterials are receiving increasing attention due to their potential application to light-driven degradation of water and gas-phase pollutants. However, to exploit the strong potential of photoactive materials and access their properties require a fine tuning of their size/shape dependent chemical-physical properties and on the ability to integrate them in photo-reactors or to deposit them on large surfaces. Therefore, the synthetic approach, as well as post-synthesis manipulation could strongly affect the final photocatalytic properties of nanomaterials. The potential application of photoactive nanomaterials in the environmental field includes the abatement of organic pollutant in water, water disinfection, and abatement of gas-phase pollutants in outdoor and indoor applications.

Governance, inclusion and trust in Singapore, Hong Kong and Macao

2015 ◽  
Vol 4 (3) ◽  
pp. 250-264
Author(s):  
Chiew Siang Bryan Ho
Keyword(s):  
Hong Kong ◽  
Current Literature ◽  
Potential Application ◽  
Design Methodology ◽  
Good Governance ◽  
Empirical Studies ◽  
Special Issue ◽  
Content Type ◽  
Developmental States

Purpose – The contributions in this special issue focus specifically on pertinent issues concerning governance in Asian developmental states – Singapore, Hong Kong, and Macao. The purpose of this paper is to provide, first of all, an overview of conceptual issues on governance and its potential application for addressing the rise and development of Asia’s successful developmental states – Singapore, Hong Kong, and Macao. Design/methodology/approach – This introduction will show the relevance of these contributions theoretically, methodologically, and empirically in relation to the current literature on governance studies. Findings – The overview section links the theoretical and conceptual considerations with the empirical studies on either single country or a comparison between states. Originality/value – The concluding remarks point to the lessons drawn from these contributions and the implication(s) for further research in good governance.

scholarly journals (−)-Homosalinosporamide A and Its Mode of Proteasome Inhibition: An X-ray Crystallographic Study

Marine Drugs ◽  
2018 ◽  
Vol 16 (7) ◽  
pp. 240 ◽  
Author(s):  
Michael Groll ◽  
Henry Nguyen ◽  
Sreekumar Vellalath ◽  
Daniel Romo
Keyword(s):  
Natural Product ◽  
Active Site ◽  
Late Stage ◽  
Enzyme Assay ◽  
Proteasome Inhibition ◽  
Fine Tuning ◽  
Synthetic Approach ◽  
X Ray ◽  
Salinosporamide A ◽  
Crystallographic Study

Upon acylation of the proteasome by the β-lactone inhibitor salinosporamide A (SalA), tetrahydrofuran formation occurs by intramolecular alkylation of the incipient alkoxide onto the choroethyl sidechain and irreversibly blocks the active site. Our previously described synthetic approach to SalA, utilizing a bioinspired, late-stage, aldol-β-lactonization strategy to construct the bicyclic β-lactone core, enabled synthesis of (–)-homosalinosporamide A (homoSalA). This homolog was targeted to determine whether an intramolecular tetrahydropyran is formed in a similar manner to SalA. Herein, we report the X-ray structure of the yeast 20S proteasome:homoSalA-complex which reveals that tetrahydropyran ring formation does not occur despite comparable potency at the chymotrypsin-like active site in a luminogenic enzyme assay. Thus, the natural product derivative homoSalA blocks the proteasome by a covalent reversible mode of action, opening the door for further fine-tuning of proteasome inhibition.

scholarly journals Towards Scaling-up Photocatalytic Process for Multiphase Environmental Applications: A Review

2021 ◽  
Author(s):  
Mohamed Gar Alalm ◽  
Ridha Djellabi ◽  
Daniela Meroni ◽  
Carlo Pirola ◽  
Claudia L. Bianchi ◽  
...  
Keyword(s):  
Gas Phase ◽  
Large Scale ◽  
Research Practice ◽  
Photocatalytic Process ◽  
Practical Application ◽  
Wastewater Purification ◽  
Photocatalytic Reactors ◽  
Practice Gaps ◽  
Critical Overview ◽  
Degradation Of Pollutants

Recently, we have witnessed a booming development of composites and multi-dopant metal oxides to be employed as novel photocatalysts. Yet the practical application of photocatalysis for environmental purposes is still elusive. Concerns about the unknown fate and toxicity of nanoparticles, unsatisfactory performance in real conditions, mass transfer limitations and durability issues have so far discouraged investments in full-scale applications of photocatalysis. Herein, we provide a critical overview of the main challenges that are limiting large-scale application of photocatalysis in air and water/wastewater purification. We then discuss the main approaches reported in the literature to tackle these shortcomings, such as the design of photocatalytic reactors that retain the photocatalyst, the study of degradation of micropollutants in different water matrices, and the development of gas-phase reactors with optimized contact time and irradiation. Furthermore, we provide a critical analysis of research-practice gaps such as treatment of real water and air samples, degradation of pollutants with actual environmental concentrations, photocatalyst deactivation, and cost and environmental life-cycle assessment.

scholarly journals Predicting Elemental Boiling Points from First Principles

2020 ◽  
Author(s):  
Jan-Michael Mewes
Keyword(s):  
Gas Phase ◽  
First Principles ◽  
Boiling Point ◽  
Density Functional ◽  
Ambient Pressure ◽  
Fundamental Property ◽  
Fine Tuning ◽  
Free Energies ◽  
Absolute Deviation ◽  
Similar Accuracy

<div>The normal boiling point (NBP) is a fundamental property of liquids and marks the intersection of the Gibb’s free energies of the liquid and the gas phase at ambient pressure. In this work, we present the first comprehensive demonstration of an approach to calculate the boiling point of atomic liquids from first-principles molecular-dynamics simulations. To this end, we combine thermodynamic integration (TDI) and perturbation theory (TPT) with a density-functional theory (DFT) Hamiltonian to deliver converged absolute liquid free energies and entropies. Linear extrapolation to the intersection with the gas phase provides NBPs, which are corrected for systematic over- or under-binding of the DFT Hamiltonian, thereby eliminating any strong dependency on the density functional. Through fine-tuning of the TDI, we reduced the walltime from weeks to about a day per element (10 − 20k core-hours), which enables extensive testing for B, Al, Na, K, Ca, Sr, Ba, Mn, Cu, Xe and Hg. This demonstrates the excellent performance and particular robustness of the approach. With a mean absolute deviation (MAD) of less than 2% from experimental references, and very similar accuracy for liquid entropies (MAD 2.3 J/(mol*K), 2% relative), the overall deviation is several times smaller than the variation between literature values for several elements.</div>

scholarly journals Intercalated Iron Chalcogenides: Phase Separation Phenomena and Superconducting Properties

2021 ◽  
Vol 9 ◽  
Author(s):  
Anna Krzton-Maziopa
Keyword(s):  
Alkali Metals ◽  
Organic Molecules ◽  
Chemical Nature ◽  
Building Blocks ◽  
Fine Tuning ◽  
Synthetic Approach ◽  
Superconducting Properties ◽  
Iron Chalcogenides ◽  
Organic Guests ◽  
Inorganic Layers

Organic molecule-intercalated layered iron-based monochalcogenides are presently the subject of intense research studies due to the linkage of their fascinating magnetic and superconducting properties to the chemical nature of guests present in the structure. Iron chalcogenides have the ability to host various organic species (i.e., solvates of alkali metals and the selected Lewis bases or long-chain alkylammonium cations) between the weakly bound inorganic layers, which opens up the possibility for fine tuning the magnetic and electrical properties of the intercalated phases by controlling both the doping level and the type/shape and orientation of the organic molecules. In recent years, significant progress has been made in the field of intercalation chemistry, expanding the gallery of intercalated superconductors with new hybrid inorganic–organic phases characterized by transition temperatures to a superconducting state as high as 46 K. A typical synthetic approach involves the low-temperature intercalation of layered precursors in the presence of liquid amines, and other methods, such as electrochemical intercalation, intercalant or ion exchange, and direct solvothermal growths from anhydrous amine-based media, are also being developed. Large organic guests, while entering a layered structure on intercalation, push off the inorganic slabs and modify the geometry of their internal building blocks (edge-sharing iron chalcogenide tetrahedrons) through chemical pressure. The chemical nature and orientation of organic molecules between the inorganic layers play an important role in structural modification and may serve as a tool for the alteration of the superconducting properties. A variety of donor species well-matched with the selected alkali metals enables the adjustment of electron doping in a host structure offering a broad range of new materials with tunable electric and magnetic properties. In this review, the main aspects of intercalation chemistry are discussed, involving the influence of the chemical and electrochemical nature of intercalating species on the crystal structure and critical issues related to the superconducting properties of the hybrid inorganic–organic phases. Mutual relations between the host and organic guests lead to a specific ordering of molecular species between the host layers, and their effect on the electronic structure of the host will be also argued. A brief description of a critical assessment of the association of the most effective chemical and electrochemical methods, which lead to the preparation of nanosized/microsized powders and single crystals of molecularly intercalated phases, with the ease of preparation of phase pure materials, crystal sizes, and the morphology of final products is given together with a discussion of the stability of the intercalated materials connected with the volatility of organic solvents and a possible degradation of host materials.

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