Aspirin alleviates orthopedic implant‑associated infection.

Implant‑associated infection (IAI), a common condition marked by progressive inflammation and bone destruction, is mentally and financially devastating to those it affects, causing severe morbidity, prolonged hospital admissions, significant hospital costs and, in certain cases, mortality. Aspirin, a popular synthetic compound with a history of >100 years, is antipyretic, anti‑inflammatory and analgesic. It is the most active component of non‑steroidal anti‑inflammatory drugs.

Nanocavity-Enhanced Giant Stimulated Raman Scattering in Si Nanowires in the Visible Light Region.

Silicon photonics has been a very active area of research especially in the past two decades in order to meet the ever-increasing demand for more computational power and faster device speeds and their natural compatibility with complementary metal-oxide semiconductor. In order to develop Si as a useful photonics material, essential photonic components such as light sources, waveguides, wavelength convertors, modulators, and detectors need to be developed and integrated. However, due to the indirect electronic bandgap of Si, conventional light emission devices such as light-emitting diodes and lasers cannot be built.

Anion Exchange in II-VI Semiconducting Nanostructures via Atomic Templating.

Controlled chemical transformation of nanostructures is a promising technique to obtain precisely designed novel materials, which are difficult to synthesize otherwise. We report high-temperature vapor-phase anion-exchange reactions to chemically transform II-VI semiconductor nanostructures (100-300 nm length scale) while retaining the single crystallinity, crystal structure, morphology, and even defect distribution of the parent material via atomic templating. The concept of atomic templating is employed to obtain kinetically controlled, thermodynamically metastable structural phases such as zincblende CdSe and CdS from zincblende CdTe upon complete chemical replacement of Te with Se or S.

Strong modulation of second-harmonic generation with very large contrast in semiconducting CdS via high-field domain.

Dynamic control of nonlinear signals is critical for a wide variety of optoelectronic applications, such as signal processing for optical computing. However, controlling nonlinear optical signals with large modulation strengths and near-perfect contrast remains a challenging problem due to intrinsic second-order nonlinear coefficients via bulk or surface contributions. Here, via electrical control, we turn on and tune second-order nonlinear coefficients in semiconducting CdS nanobelts from zero to up to 151 pm V, a value higher than other intrinsic nonlinear coefficients in CdS.

Engineering Localized Surface Plasmon Interactions in Gold by Silicon Nanowire for Enhanced Heating and Photocatalysis.

The field of plasmonics has attracted considerable attention in recent years because of potential applications in various fields such as nanophotonics, photovoltaics, energy conversion, catalysis, and therapeutics. It is becoming increasing clear that intrinsic high losses associated with plasmons can be utilized to create new device concepts to harvest the generated heat. It is therefore important to design cavities, which can harvest optical excitations efficiently to generate heat.

Nanotwin Detection and Domain Polarity Determination via Optical Second Harmonic Generation Polarimetry.

We demonstrate that optical second harmonic generation (SHG) can be utilized to determine the exact nature of nanotwins in noncentrosymmetric crystals, which is challenging to resolve via conventional transmission electron or scanned probe microscopies. Using single-crystalline nanotwinned CdTe nanobelts and nanowires as a model system, we show that SHG polarimetry can distinguish between upright (Cd-Te bonds) and inverted (Cd-Cd or Te-Te bonds) twin boundaries in the system. Inverted twin boundaries are generally not reported in nanowires due to the lack of techniques and complexity associated with the study of the nature of such defects.

Emission energy, exciton dynamics and lasing properties of buckled CdS nanoribbons.

We report the modulation of emission energy, exciton dynamics and lasing properties in a single buckled CdS nanoribbon (NR) by strain-engineering. Inspired by ordered structure fabrication on elastomeric polymer, we develop a new method to fabricate uniform buckled NRs supported on polydimethylsiloxane (PDMS). Wavy structure, of which compressive and tensile strain periodically varied along the CdS NR, leads to a position-dependent emission energy shift as large as 14 nm in photoluminescence (PL) mapping.

Crystallographic Characterization of II-VI Semiconducting Nanostructures via Optical Second Harmonic Generation.

We demonstrate the utility of optical second harmonic generation (SHG) polarimetry to perform structural characterization of noncentrosymmetric, single-crystalline II-VI semiconducting nanowires, nanobelts, and nanoflakes. By analyzing anisotropic SHG polarimetric patterns, we distinguish between wurtzite and zincblende II-VI semiconducting crystal structures and determine their growth orientation. The crystallography of these nanostructures was then confirmed via transmission electron microscopy measurements performed on the same system.

Giant enhancement of second harmonic generation by engineering double plasmonic resonances at nanoscale.

We have investigated second harmonic generation (SHG) from Ag-coated LiNbO₃(LN) core-shell nanocuboids and found that giant SHG can occur via deliberately designed double plasmonic resonances. By controlling the aspect ratio, we can tune fundamental wave (FW) and SHG signal to match the longitudinal and transverse plasmonic modes simultaneously, and achieve giant enhancement of SHG by 3 × 10(5) in comparison to a bare LN nanocuboid and by about one order of magnitude to the case adopting only single plasmonic resonance. The underlying key physics is that the double-resonance nanoparticle enables greatly enhanced trapping and harvesting of incident FW energy, efficient internal transfer of optical energy from FW to the SHG signal, and much improved power to transport the SHG energy from the nanoparticle to the far-field region.

Enhanced second-harmonic generation from metal-integrated semiconductor nanowires via highly confined whispering gallery modes.

Coherent and tunable nanoscale light sources utilizing optical nonlinearities are required for applications ranging from imaging and bio-sensing to on-chip all-optical signal processing. However, owing to their small sizes, the efficiency of nanostructures even with high nonlinear coefficients is poor, therefore requiring very high excitation energies. Although surface-plasmon resonances of metal nanostructures can enhance surface nonlinear processes such as second-harmonic generation, they still suffer from low conversion efficiencies owing to their intrinsically low nonlinear coefficients.

Resolving parity and order of Fabry-Pérot modes in semiconductor nanostructure waveguides and lasers: Young's interference experiment revisited.

Semiconductor nanostructures such as nanowires and nanoribbons functioning as Fabry-Pérot (F-P)-type optical cavities and nanolasers have attracted great interest not only for their potential use in nanophotonic systems but also to understand the physics of light-matter interactions at the nanoscale. Due to their nanoscale dimensions, new techniques need to be continuously developed to characterize the nature of highly confined optical modes. Furthermore, the inadequacy of typical far-field photoluminescence experiments for characterizing the nanoscale cavity modes such as parity and order has precluded efforts to obtain precise information that is required to fully understand these cavities.

Adipose-derived stem cells induced dendritic cells undergo tolerance and inhibit Th1 polarization.

Adipose tissue-derived stem cells (ADSC) have been shown to possess stem cell properties such as transdifferentiation, self-renewal and therapeutic potential. However, the property of ADSC to accommodate immune system is still unknown. In this study, ADSC were cocultured with allogenetic dendritic cells (DC), and then treated DC were mixed with allogenetic CD4+ T cells.

Allogeneic adipose-derived stem cells with low immunogenicity constructing tissue-engineered bone for repairing bone defects in pigs.

The ideal cells for tissue engineering should have the following characteristics: easy obtainment, safety, immune privilege, the capability of self-renewal, and multipotency. Adipose-derived stem cells (ADSCs) are a promising candidate. However, the immunogenicity of allogeneic mesenchymal stem cells limits their long-term benefits.

Amplified spontaneous emission of surface plasmon polaritons with unusual angle-dependent response.

Loss issues are fundamentally crucial for the application of surface plasmon polaritons (SPPs). In this study the amplified spontaneous emission (ASE) of SPPs in a typical Kretschmann configuration is observed and shows an unusually broadened angular response with increased pump intensity. Theoretical models are further developed to verify the results and understand the amplification of SPPs in Fourier space.

Experimental demonstration of super quasi-phase matching in nonlinear photonic crystal.

We have demonstrated super quasi-phase matching (QPM) in a super periodically poled lithium niobate (PPLN), which is composed of multiple ordinary PPLN cells. When super QPM is achieved, the slight phase mismatch in each PPLN cell can be further compensated for, and the relevant second harmonic generation is facilitated greatly. This mechanism provides an insightful means to relieve the limitation imposed by sample fabrication inaccuracy and will open up a promising avenue toward highly efficient nonlinear interactions.

Heparin-chitosan-coated acellular bone matrix enhances perfusion of blood and vascularization in bone tissue engineering scaffolds.

Currently, the main hurdle in the tissue engineering field is how to provide sufficient blood supply to grafted tissue substitutes in the early post-transplanted period. For three-dimensional, cell-dense, thick tissues to survive after transplantation, treatments are required for hypoxia, nutrient insufficiency, and the accumulation of waste products. In this study, a biomacromolecular layer-by-layer coating process of chitosan/heparin onto a decellularized extracellular bone matrix was designed to accelerate the blood perfusion and re-endothelialization process.

Exact iterative solution of second harmonic generation in quasi-phase-matched structures.

A versatile and accurate approach that combines a numerical iteration technique and a transfer-matrix method (TMM) is developed to solve the general problem of second harmonic generation (SHG) with pump depletion in quasi-phase-matched (QPM) nonlinear optical structures. We derive the iterative formulae from the nonlinear coupled wave equations and obtain the intensity distribution of fundamental wave and second harmonic wave by TMM. The approach shows quick numerical convergence of iteration and maintains perfect conservation of total energy.

Giant enhancement of second harmonic generation in nonlinear photonic crystals with distributed Bragg reflector mirrors.

We theoretically investigate second harmonic generation (SHG) in one-dimensional multilayer nonlinear photonic crystal (NPC) structures with distributed Bragg reflector (DBR) as mirrors. The NPC structures have periodic modulation on both the linear and second-order susceptibility. Three major physical mechanisms, quasi-phase matching (QPM) effect, slow light effect at photonic band gap edges, and cavity effect induced by DBR mirrors can be harnessed to enhance SHG.