Development Of Surface Chemistry Research Articles

Delocalized magnetism in low-dimensional graphene system

Delocalized p-shell electron magnetism emerging in a low-dimensional graphene system due to quantum effect is distinct from the localized d/f-shell electron’s. The delocalization effect allows the precise engineering of the magnetic ground state and magnetic exchange interactions in nanographenes, thus implementing the accurate construction of high-quality graphene-based magnetic quantum materials. In recent years, with the development of surface chemistry and surface physics, it has become feasible to study the magnetism of nanographenes with single-atom precision, thus opening a new research direction for studying purely organic quantum magnetism. This review starts from the summarizing of the research background of nanographene magnetism. Then, the physics nature behind the nanographene magnetism and recent experimental researches are discussed. Finally, the challenges and opportunities for further studying low-dimensional magnetic graphenes are briefly discussed.

Next Generation Methods for Single-Molecule Force Spectroscopy on Polyproteins and Receptor-Ligand Complexes.

Single-molecule force spectroscopy with the atomic force microscope provides molecular level insights into protein function, allowing researchers to reconstruct energy landscapes and understand functional mechanisms in biology. With steadily advancing methods, this technique has greatly accelerated our understanding of force transduction, mechanical deformation, and mechanostability within single- and multi-domain polyproteins, and receptor-ligand complexes. In this focused review, we summarize the state of the art in terms of methodology and highlight recent methodological improvements for AFM-SMFS experiments, including developments in surface chemistry, considerations for protein engineering, as well as theory and algorithms for data analysis. We hope that by condensing and disseminating these methods, they can assist the community in improving data yield, reliability, and throughput and thereby enhance the information that researchers can extract from such experiments. These leading edge methods for AFM-SMFS will serve as a groundwork for researchers cognizant of its current limitations who seek to improve the technique in the future for in-depth studies of molecular biomechanics.

Porosity and surface chemistry development and thermal degradation of textile waste jute during recycling as activated carbon

Textile waste jute was activated by H3PO4 and ZnCl2 for reuse as activated carbon. Thermal degradation behavior of jute, impregnated jute and activating agents via thermogravimetric analysis were conducted first. Yield and iodine adsorption number were employed to determine the optimal activation conditions. As a result, activation by H3PO4 was best conducted at 700 °C for 90 min with an impregnation ration of 1.0 while conditions for ZnCl2 were 500 °C, 60 min and impregnation ratio of 1.0. That is, the best activation conditions varied with activating agents. So were the properties of resultant jute-based activated carbons. H3PO4 activation produced an activated carbon that was mostly mesoporous while that by ZnCl2 was more even in micropore and mesopore volumes as proven by pore volume distribution analysis. In addition, both carbons were abundant in surface functional groups which could be beneficial for adsorption of pollutants. Overall, jute could be effectively recycled to produce activated carbon that boasted excellent surface chemistry and textual properties.

First-principles modelling of scanning tunneling microscopy using non-equilibrium Green’s functions

The investigation of electron transport processes in nano-scale architectures plays a crucial role in the development of surface chemistry and nano-technology. Experimentally, an important driving force within this research area has been the concurrent refinements of scanning tunneling microscopy (STM) techniques. The theoretical treatment of the STM operation has traditionally been based on the Bardeen and Tersoff-Hamann methods which take as input the single-particle wave functions and eigenvalues obtained from finite cluster or slabs models of the surface-tip interface. Here, we present a novel STM simulation scheme based on non-equilibrium Green’s functions (NEGF) and Wannier functions which is both accurate and very efficient. The main novelty of the scheme compared to the Bardeen and Tersoff-Hamann approaches is that the coupling to the infinite (macroscopic) electrodes is taken into account. As an illustrating example we apply the NEGF-STM method to the Si(001)-(2×1):H surface with sub-surface P doping and discuss the results in comparison to the Bardeen and Tersoff-Hamann methods.

Study of Cherry Stones as a Precursor in the Preparation of Low Cost Carbonaceous Adsorbent

A cherry stone-based activated carbon was electrochemically and chemically oxidized to enhance its adsorbent property for comparison with as-produced. The samples obtained were characterized by Boehm's titration, pH titration, zeta potential measurement, FT-IR, Brunauer–Emmet–Teller surface area, and pore size distribution. A significant increase in the concentration of surface functional groups was obtained from the oxidation of the samples due to the introduction of oxygen-containing functional groups, as confirmed by Boehm's titration, FT-IR, PZC, and IEP analyses. Activation methods significantly improved the amount of oxygen-containing surface functional groups that make the carbonaceous adsorbents more hydrophilic and acidic, decreasing the pH of their point of zero charge, and increasing their surface charge density. The activated carbon samples obtained were predominantly microporous, and their pore volumes decreased as a function of activation period and temperature. The surface chemistry development of carbons was correlated to increasing removal ability of heavy metals.

Microarray Technology as a Universal Tool for High-Throughput Analysis of Biological Systems

Over the last years microarray technology has become one of the principal platform technologies for the high-throughput analysis of biological systems. Starting with the construction of first DNA microarrays in the 1990s, microarray technology has flourished in the last years and many different new formats have been developed. Peptide and protein microarrays are now applied for the elucidation of interaction partners, modification sites and enzyme substrates. Antibody microarrays are envisaged to be of high importance for the high-throughput determination of protein abundances in translational profiling approaches. First cell microarrays have been constructed to transform microarray technology from an in vitro technology to an in vivo functional analysis tool. All of these approaches share a common prerequisite: the solid support on which they are generated. The demands on this solid support are thereby as manifold as the applications themselves. This review is aimed to display the recent developments in surface chemistry and derivatization, and to summarize the latest developments in the different application areas of microarray technology.

Advances in fluorescence imaging with quantum dot bio-probes

After much effort in surface chemistry development and optimization by several groups, fluorescent semiconductor nanocrystals probes, also known as quantum dots or qdots, are now entering the realm of biological applications with much to offer to biologists. The road to success has been paved with hurdles but from these efforts has stemmed a multitude of original surface chemistries that scientists in the biological fields can draw from for their specific biological applications. The ability to easily modulate the chemical nature of qdot surfaces by employing one or more of the recently developed qdot coatings, together with their exceptional photophysics have been key elements for qdots to acquire a status of revolutionary fluorescent bio-probes. Indeed, the unique properties of qdots not only give biologists the opportunity to explore advanced imaging techniques such as single molecule or lifetime imaging but also to revisit traditional fluorescence imaging methodologies and extract yet unobserved or inaccessible information in vitro or in vivo.

Morphology Development of Ultrathin Symmetric Diblock Copolymer Film via Solvent Vapor Treatment

We have followed the time development of the microdomain structure in symmetric diblock copolymer poly(styrene-b-methyl methacrylate), P(S-b-MMA), ultrathin films via PMMA-selective solvent vapor treatment by atomic force microscopy (AFM). After preparation on a substrate preferentially attracting the PMMA block, PS forms a continuous layer at a film's free surface. With subsequent solvent vapor treatment, the film gradually shows a well-ordered hexagonally packed nanocylinders structure. It is shown that only when the film thickness is less than the 1/2L0 (lamellar repeat spacing), and exposed to PMMA block selective solvent for an appropriate time, can the well-ordered hexagonally packed nanocylinders form. On an extended solvent vapor treatment, a mixed morphology containing nanocylinders and stripes appears, followed by the striped morphologies. When the annealing time is long enough, the film comes back to the flat surface again, however, with PMMA instead of PS dominating the free surface. Thickness confinement and solvent induced reconstruction of the film are shown to be responsible for the P(S-b-MMA) morphology and surface chemistry development.

Co-ion dependence of DNA nuclease activity suggests hydrophobic cavitation as a potential source of activation energy

The source of the activation energy that allows cutting of DNA by restriction enzymes is unclear. A systematic study of the cutting efficiency of the type-II restriction endonuclease EcoRI, with varying background electrolyte ion pair and buffer reported here, shows only a modest dependence of efficiency on cation type. Surprisingly, efficiency does depend strongly on the presumed indifferent anion of the background salt. What emerges is that competition between the background salt anion and the buffer anion for the enzyme and DNA surfaces is crucial. The results are unexpected and counterintuitive from the point of view of conventional electrolyte theory. However, taken together with recent developments in surface chemistry, the results do fall into place and could also suggest a novel mechanism for enzyme activity as an alternative to metal-activated hydrolysis: microscopic cavitation in a hydrophobic pocket might be the source of activation energy.