The interest in mid-infrared technologies surrounds plenty of important optoelectronic applications ranging from optical communications, biomedical imaging to night vision cameras, and so on. Although narrow bandgap semiconductors, such as Mercury Cadmium Telluride and Indium Antimonide, and quantum superlattices based on inter-subband transitions in wide bandgap semiconductors, have been employed for mid-infrared applications, it remains a daunting challenge to search for other materials that possess suitable bandgaps in this wavelength range. Here, we demonstrate experimentally for the first time that two-dimensional (2D) atomically thin PtSe2 has a variable bandgap in the mid-infrared via layer and defect engineering. Here, we show that bilayer PtSe2 combined with defects modulation possesses strong light absorption in the mid-infrared region, and we realize a mid-infrared photoconductive detector operating in a broadband mid-infrared range. Our results pave the way for atomically thin 2D noble metal dichalcogenides to be employed in high-performance mid-infrared optoelectronic devices.

Nanoparticle technology plays a key role in providing opportunities and possibilities for the development of new generation of sensing tools. The targeted sensing of selective biomolecules using functionalized gold nanoparticles (Au NPs) has become a major research thrust in the last decade. Au NP-based sensors are expected to change the very foundations of sensing and detecting biomolecules. In this review, we will discuss the use of surface functionalized Au NPs for smart sensor fabrication leading to detection of specific biomolecules and heavy metal ions.

Considerable progress in wireless power transfer has been made in the realm of non-radiative transfer, which employs magnetic-field coupling in the near field. A combination of circuit resonance and impedance transformation is often used to help to achieve efficient transfer of power over a predetermined distance of about the size of the resonators. The development of non-radiative wireless power transfer has paved the way towards real-world applications such as wireless powering of implantable medical devices and wireless charging of stationary electric vehicles. However, it remains a fundamental challenge to create a wireless power transfer system in which the transfer efficiency is robust against the variation of operating conditions. Here we propose theoretically and demonstrate experimentally that a parity-time-symmetric circuit incorporating a nonlinear gain saturation element provides robust wireless power transfer. Our results show that the transfer efficiency remains near unity over a distance variation of approximately one metre, without the need for any tuning. This is in contrast with conventional methods where high transfer efficiency can only be maintained by constantly tuning the frequency or the internal coupling parameters as the transfer distance or the relative orientation of the source and receiver units is varied. The use of a nonlinear parity-time-symmetric circuit should enable robust wireless power transfer to moving devices or vehicles.

Studies on hypoxia-sensitive pathways have revealed a series of Fe(II)-dependent dioxygenases that regulate hypoxia-inducible factor (HIF) by prolyl and asparaginyl hydroxylation. The recognition of these unprecedented signaling processes has led to a search for other substrates of the HIF hydroxylases. Here we show that the human HIF asparaginyl hydroxylase, factor inhibiting HIF (FIH), also efficiently hydroxylates specific asparaginyl (Asn)-residues within proteins of the IB family. After the identification of a series of ankyrin repeat domain (ARD)-containing proteins in a screen for proteins interacting with FIH, the ARDs of p105 (NFKB1) and IB␣ were shown to be efficiently hydroxylated by FIH at specific Asn residues in the hairpin loops linking particular ankyrin repeats. The target Asn residue is highly conserved as part of the ankyrin consensus, and peptides derived from a diverse range of ARDcontaining proteins supported FIH enzyme activity. These findings demonstrate that this type of protein hydroxylation is not restricted to HIF and strongly suggest that FIH-dependent ARD hydroxylation is a common occurrence, potentially providing an oxygen-sensitive signal to a diverse range of processes.NF-B ͉ 2-oxoglutarate-dependent dioxygenase ͉ protein hydroxylation C ells react to variation in oxygen availability with adaptive responses that involve changes in most basic cellular functions. Analysis of the transcriptional component of this response has defined pathways that regulate hypoxia-inducible factor (HIF) by posttranslational hydroxylation of specific residues. HIF is an ␣͞␤ heterodimer that binds hypoxia response elements in a range of hypoxia-inducible genes (for review, see ref. 1). Regulation is mediated by the ␣-subunits and involves dual mechanisms controlling both the abundance and activity of the protein. Thus, hydroxylation of specific prolyl residues promotes interaction with the von Hippel-Lindau E3 ligase and hence proteolysis, whereas hydroxylation of a C-terminal Asn residue blocks recruitment of the coactivators p300͞CBP. The prolyl and asparaginyl hydroxylase enzymes that catalyze these reactions are 2-oxoglutarate (2-OG) and Fe(II)-dependent dioxygenases that couple the oxidative decarboxylation of 2-OG with oxidation of peptidyl substrates. Dioxygen is an obligate cosubstrate, and reductions in the rate of hydroxylation during hypoxia allow HIF-␣ to escape VHLmediated destruction and to activate transcription (for reviews, see refs. 2 and 3).HIF prolyl hydroxylation is catalyzed by three enzymes, PHD1, -2, and -3 (equivalent to EGLN2, -1, and -3 and HPH-3, -2, and -1). HIF Asn hydroxylation is catalyzed by a more distantly related 2-OG-dependent dioxygenase, factor inhibiting HIF (FIH) (for reviews, see refs. 2 and 3). A key question raised by these findings is whether the roles of all four dioxygenases are specific to HIF regulation, or whether one or more have alternative substrates. Several studies have identified proteins that interact to modulate HIF hydroxylase activity (4) or ...

P-Glycoprotein (Pgp) was isolated from CHRC5 membranes by selective detergent extraction and further purified by lentil lectin affinity chromatography. The purified product displayed a very high basal ATPase activity (1.65 mumol/min per mg protein in the absence of added drugs or lipids) with an apparent Km for ATP of 0.4 mM. There was no evidence of cooperativity, suggesting that the two ATP sites operate independently of each other. Pgp ATPase activity was stimulated by verapamil, trifluoperazine and colchicine, and inhibited by daunomycin and vinblastine. All drugs and chemosensitizers acted as mixed activators or inhibitors, producing changes in both the Vmax of the ATPase and the Km for ATP. ADP competitively inhibited Pgp ATPase, with a Ki of 0.2 mM. The macrolide antibiotics bafilomycin A1, concanamycin A and concanamycin B, inhibited Pgp ATPase at concentrations of 0.1-10 microM, and at an inhibitor:protein stoichiometry of 0.65-1.0 mumol/mg protein, which is at the low end of the range characteristic of P-type ATPases. Pgp ATPase was relatively selective for adenine nucleotides. Several phospholipids stimulated Pgp ATPase activity in a dose-dependent manner, whereas others produced inhibition. Metabolic labelling showed that the endogenous phospholipids associated with purified Pgp consisted largely of phosphatidylethanolamine and phosphatidylserine, with only a small amount of phosphatidylcholine. 32P-Labelling studies indicated that purified Pgp was partially phosphorylated. It can be concluded that Pgp is a constitutively active, adenine nucleotide-specific ATPase whose catalytic activity can be modulated by both drugs and phospholipids.