J. Appl. Cryst.の発刊に際して

The nature and characteristics of the CH/π interaction are discussed by comparison with other weak molecular forces such as the CH/O and OH/π interaction. The CH/π interaction is a kind of hydrogen bond operating between a soft acid CH and a soft base π-system (double and triple bonds, C6 and C5 aromatic rings, heteroaromatics, convex surfaces of fullerenes and nanotubes). The consequences of CH/π hydrogen bonds in supramolecular chemistry are reviewed on grounds of recent crystallographic findings and database analyses. The topics include intramolecular interactions, crystal packing (organic and organometallic compounds), host/guest complexes (cavity-type inclusion compounds of cyclodextrins and synthetic macrocyclic hosts such as calixarenes, catenanes, rotaxanes and pseudorotaxanes), lattice-inclusion type clathrates (including liquid crystals, porphyrin derivatives, cyclopentadienyl compounds and C60 fullerenes), enantioselective clathrate formation, catalytic enantioface discriminating reactions and solid-state photoreaction. The implications of the CH/π concept for crystal engineering and drug design are evident.

CH/π hydrogen bonds in crystals

Carbon dots: synthesis, formation mechanism, fluorescence origin and sensing applications

A review on dynamic mechanical properties of natural fibre reinforced polymer composites

This review summarizes recent progress in the design and applications of cadmium-free quantum dots (Cd-free QDs), with an emphasis on their role in biophotonics and nanomedicine. We first present the features of Cd-free QDs and describe the physics and emergent optical properties of various types of Cd-free QDs whose applications are discussed in subsequent sections. Selected specific QD systems are introduced, followed by the preparation of these Cd-free QDs in a form useful for biological applications, including recent advances in achieving high photoluminescence quantum yield (PL QY) and tunability of emission color. Next, we summarize biophotonic applications of Cd-free QDs in optical imaging, photoacoustic imaging, sensing, optical tracking, and photothermal therapy. Research advances in the use of Cd-free QDs for nanomedicine applications are discussed, including drug/gene delivery, protein/peptide delivery, image-guided surgery, diagnostics, and medical devices. The review then considers the pharma...

New Generation Cadmium-Free Quantum Dots for Biophotonics and Nanomedicine

Studies on mechanical, thermal and dynamic mechanical properties of untreated (raw) and treated coconut sheath fiber reinforced epoxy composites

A rapid and sensitive fluorescent sensor based on the MoS2 nanosheet/DNA/carbon dot nanoassembly has been developed towards the detection of mercury(II) present in environmental samples. Bio-carbon dots (CDs) having strong fluorescence maxima at 451 nm were synthesized via one-step treatment with honey under low temperature carbonization. These CDs were nearly spherical with good size distribution and excellent monodispersity, and the average sizes of CD were around 2–4 nm as evidenced from transmission electron microscopy. The conjugation of DNA strands on the surface of the carbon dots provided an efficient fluorescent probe. The fluorescence of the MoS2 nanosheet/DNA/carbon dot nanoassembly enhanced gradually with the increase in the concentration of Hg2+ ions and the detection limit was found to be 1.02 nM. Furthermore, the fluorescence intensity was found to be linear with the concentration of Hg2+ ions in the range from 0 to 10 nM and their respective coefficient of determination was found to be 0.93676 and 0.98178. The present MoS2 nanosheet/DNA/carbon dot nanoassembly is highly selective toward Hg2+ ions over a wide range of metal ions tested.

Sensitive fluorescence detection of mercury(II) in aqueous solution by the fluorescence quenching effect of MoS2 with DNA functionalized carbon dots

Corrosion inhibition of mild steel in 1.0 M hydrochloric acid medium by new photo-cross-linkable polymers

Commercial-purity aluminium (CP-Al) was laser alloyed with electrodeposited nickel using a high-power CW CO 2 laser. For process optimisation, nickel was electroplated at 12, 24 and 35 μm thickness, and different laser processing conditions were used. The nickel-alloyed aluminium attained a Vickers hardness of 300–950 HV, which is considerably higher than the base aluminium hardness of 35 HV. The laser-alloyed coating (LAC) contains intermetallic nickel–aluminide phases and a dendrite microstructure. The 35 μm thick nickel layer is efficient in laser alloying CP-Al for producing a homogenous coating layer (at a laser energy density of 4.1 kJ) with a high hardness of 600–950 HV and a large case depth (650 μm).

Laser alloying of aluminium with electrodeposited nickel: optimisation of plating thickness and processing parameters

The new tetraaryl substituted imidazole-based diamines were designed and synthesized through Debus–Radziszewski imidazole synthesis, and characterized by FT-IR, 1H NMR spectroscopy and MASS spectroscopy. A series of new fluorescent polyimides (PI) were prepared by polymerization of the tetra substituted imidazole diamines with tetracarboxylic dianhydrides, such as pyromellitic dianhydride, naphthalene tetra carboxylic dianhydride and perylene tetra carboxylic dianhydride. These polymers were readily soluble in a variety of organic solvents and they also possess good thermal stability. The glass transition temperature of these polymers was in the range of 398–453 °C. The ultraviolet–visible absorption spectra showed that all of the polymers had absorption maxima around 344–521 nm with a fluorescence emission maxima around 420–531 nm. The electrochemical band gaps of PI-1, PI-2 and PI-3 copolymers are estimated to be 2.37, 2.17 and 2 eV, respectively. Similarly, the optical band gap of PI-1, PI-2 and PI-3 copolymers was found to be 3.15, 3.05, and 2.15 eV, respectively. These polymer exhibits fluorescence quantum yield of 0.65, 0.46, and 0.3% for PI-1, PI-2 and PI-3, respectively. The PIs also exhibited good flame retardant behavior.

Kathavarayan Subramanian

Papers

Studies on mechanical, thermal and dynamic mechanical properties of untreated (raw) and treated coconut sheath fiber reinforced epoxy composites

Sensitive fluorescence detection of mercury(II) in aqueous solution by the fluorescence quenching effect of MoS2 with DNA functionalized carbon dots

Corrosion inhibition of mild steel in 1.0 M hydrochloric acid medium by new photo-cross-linkable polymers

Laser alloying of aluminium with electrodeposited nickel: optimisation of plating thickness and processing parameters

Synthesis, photophysical and electrochemical properties of polyimides of tetraaryl imidazole