Colloidal quantum dots enable tunable liquid-state lasers.

Present-day liquid-state lasers are based on organic dyes. Here we demonstrate an alternative class of liquid lasers that use solutions of colloidal quantum dots (QDs). Previous efforts to realize such devices have been hampered by the fast non-radiative Auger recombination of multicarrier states required for optical gain.

Formation of Superhydrophobic Coatings Based on Dispersion Compositions of Hexyl Methacrylate Copolymers with Glycidyl Methacrylate and Silica Nanoparticles.

In the last decade, the task of developing environmentally friendly and cost-effective methods for obtaining stable superhydrophobic coatings has become topical. In this study, we examined the effect of the concentrations of filler and polymer binder on the hydrophobic properties and surface roughness of composite coatings made from organic-aqueous compositions based on hexyl methacrylate (HMA) and glycidyl methacrylate (GMA) copolymers. Silicon dioxide nanoparticles were used as a filler.

Two-Color Amplified Spontaneous Emission from Auger-Suppressed Quantum Dots in Liquids.

Colloidal quantum-dot (QD) lasing is normally achieved in close-packed solid-state films, as a high QD volume fraction is required for stimulated emission to outcompete fast Auger decay of optical-gain-active multiexciton states. Here a new type of liquid optical-gain medium is demonstrated, in which compact compositionally-graded QDs (ccg-QDs) that feature strong suppression of Auger decay are liquefied using a small amount of solvent. Transient absorption measurements of ccg-QD liquid suspensions reveal broad-band optical gain spanning a wide spectral range from 560 (green) to 675 nm (red).

Trapped modes in particles with a negative refractive index.

The natural oscillations of the electromagnetic field in a particle made from left-handed metamaterial, where both permittivity and permeability are negative, are considered. Based on the exact solution of the sourceless Maxwell equations, it is shown that due to the opposite directions of the phase and group velocities in the metamaterial, natural oscillations in such particles decay exponentially at infinity, that is, these natural oscillations can be considered as trapped modes with a finite energy. The manifestation of such modes in experiments with Bessel beams is also discussed.

Spin-exchange carrier multiplication in manganese-doped colloidal quantum dots.

Carrier multiplication is a process whereby a kinetic energy of a carrier relaxes via generation of additional electron-hole pairs (excitons). This effect has been extensively studied in the context of advanced photoconversion as it could boost the yield of generated excitons. Carrier multiplication is driven by carrier-carrier interactions that lead to excitation of a valence-band electron to the conduction band.

Colloidal Semiconductor Nanocrystal Lasers and Laser Diodes.

Lasers and optical amplifiers based on solution-processable materials have been long-desired devices for their compatibility with virtually any substrate, scalability, and ease of integration with on-chip photonics and electronics. These devices have been pursued across a wide range of materials including polymers, small molecules, perovskites, and chemically prepared colloidal semiconductor nanocrystals, also commonly referred to as colloidal quantum dots. The latter materials are especially attractive for implementing optical-gain media as in addition to being compatible with inexpensive and easily scalable chemical techniques, they offer multiple advantages derived from a zero-dimensional character of their electronic states.

Electrically driven amplified spontaneous emission from colloidal quantum dots.

Colloidal quantum dots (QDs) are attractive materials for realizing solution-processable laser diodes that could benefit from size-controlled emission wavelengths, low optical-gain thresholds and ease of integration with photonic and electronic circuits. However, the implementation of such devices has been hampered by fast Auger recombination of gain-active multicarrier states, poor stability of QD films at high current densities and the difficulty to obtain net optical gain in a complex device stack wherein a thin electroluminescent QD layer is combined with optically lossy charge-conducting layers. Here we resolve these challenges and achieve amplified spontaneous emission (ASE) from electrically pumped colloidal QDs.

Optically Excited Lasing in a Cavity-Based, High-Current-Density Quantum Dot Electroluminescent Device.

Laser diodes based on solution-processable materials can benefit numerous technologies including integrated electronics and photonics, telecommunications, and medical diagnostics. An attractive system for implementing these devices is colloidal semiconductor quantum dots (QDs). The progress towards a QD laser diode has been hampered by rapid nonradiative Auger decay of optical-gain-active multicarrier states, fast device degradation at high current densities required for laser action, and unfavorable competition between optical gain and optical losses in a multicomponent device stack.

Effects of Three Feed Additives on the Culturable Microbiota Composition and Histology of the Anterior and Posterior Intestines of Zebrafish ().

In this study, the effect of three promising feed additives (chelated compounds of trace elements, butyric acid, lycopene) on changes in the culturable microbiota and histological parameters of two sections of the intestines of (zebrafish) was studied. The use of these feed additives can help to eliminate the deficiency of trace elements, modulate the composition of the microbiota due to the postbiotic properties of butyric acid, and reduce oxidative stress when using lycopene. Incorporation of the investigated supplements in the feed resulted in a significant change in the relative abundance of certain groups of microorganisms.

Lyophilic and Sorption Properties of Chitosan Aerogels Modified with Copolymers Based on Glycidyl Methacrylate and Alkyl Methacrylates.

This paper discusses the influence of the structure of copolymers based on glycidyl methacrylate and alkyl methacrylates with C-C hydrocarbon side groups on the wettability and sorption properties of surface-modified chitosan aerogels. The grafting of copolymers onto the surface of aerogels was confirmed by elemental analysis, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. As a result of the modification, with an increase in the amount of the hydrocarbon substituent alkyl methacrylate, the surface of the resulting materials became hydrophobic with contact angles in the range of 146-157°.

Neuronal-Immune Cell Units in Allergic Inflammation in the Nose.

Immune cells and immune-derived molecules, endocrine glands and hormones, the nervous system and neuro molecules form the combined tridirectional neuroimmune network, which plays a significant role in the communication pathways and regulation at the level of the whole organism and local levels, in both healthy persons and patients with allergic rhinitis based on an allergic inflammatory process. This review focuses on a new research paradigm devoted to neuronal-immune cell units, which are involved in allergic inflammation in the nose and neuroimmune control of the nasal mucociliary immunologically active epithelial barrier. The categorization, cellular sources of neurotransmitters and neuropeptides, and their prevalent profiles in constituting allergen tolerance maintenance or its breakdown are discussed.

Two-band optical gain and ultrabright electroluminescence from colloidal quantum dots at 1000 A cm.

Colloidal quantum dots (QDs) are attractive materials for the realization of solution-processable laser diodes. Primary challenges towards this objective are fast optical-gain relaxation due to nonradiative Auger recombination and poor stability of colloidal QD solids under high current densities required to obtain optical gain. Here we resolve these challenges and achieve broad-band optical gain spanning the band-edge (1S) and the higher-energy (1P) transitions.

Effect of the Composition of Copolymers Based on Glycidyl Methacrylate and Fluoroalkyl Methacrylates on the Free Energy and Lyophilic Properties of the Modified Surface.

This study proposes to use reactive copolymers based on glycidyl methacrylate and fluoroalkyl methacrylates with a low fluorine content in the monomer unit as agents to reduce the surface free energy (SFE). This work reveals the effect of the structure and composition of copolymers on the SFE and water-repellent properties of these coatings. On a smooth surface, coatings based on copolymers of glycidyl methacrylate and fluoroalkyl methacrylates with fluorine atoms in the monomer unit ranging from three to seven are characterized by SFE values in the range from 25 to 13 mN/m, which is comparable to the values for polyhedral oligomeric silsesquioxanes and perfluoroalkyl acrylates.

Predictors of Complications and Unfavorable Outcomes of Minimally Invasive Surgery Treatment in Elderly Patients With Degenerative Lumbar Spine Pathologies (Case Series).

Introduction: The use of minimally invasive surgery (MIS) results in fewer adverse and more improved outcomes. However, the literature data describing the factors increasing the number of complications, reoperation frequency and unscheduled re-hospitalizations in older patients after MIS are contradictory. In this study, a large number of patients was investigated for the complications of minimally invasive surgical treatment of degenerative disease of the lumbar spine in older patients.

The influence of probiotics of different microbiological composition on histology of the gastrointestinal tract of juvenile Oncorhynchus mykiss.

This article presents results of the influence of three probiotic feed additive of various microbiological composition: Bacillus subtilis (VKPM B-2335); B. subtilis (OZ-2 VKPM-11966) + Bacillus amyloliquefaciens (OZ-3 VKPM-11967); Lactobacillus acidophilus (VKPM B-3235) on the growth and histology of the organs of the gastrointestinal tract of juvenile Oncorhynchus mykiss by morphometric parameters. These probiotic bacteria are the most commonly used in aquaculture.

Enhanced Emission from Bright Excitons in Asymmetrically Strained Colloidal CdSe/CdZnSe Quantum Dots.

Colloidal CdSe quantum dots (QDs) designed with a high degree of asymmetric internal strain have recently been shown to host a number of desirable optical properties including subthermal room-temperature line widths, suppressed spectral diffusion, and high photoluminescence (PL) quantum yields. It remains an open question, however, whether they are well-suited for applications requiring emission of identical single photons. Here we measure the low-temperature PL dynamics and the polarization-resolved fluorescence line narrowing spectra from ensembles of these strained QDs.

Semiconductor quantum dots: Technological progress and future challenges.

In quantum-confined semiconductor nanostructures, electrons exhibit distinctive behavior compared with that in bulk solids. This enables the design of materials with tunable chemical, physical, electrical, and optical properties. Zero-dimensional semiconductor quantum dots (QDs) offer strong light absorption and bright narrowband emission across the visible and infrared wavelengths and have been engineered to exhibit optical gain and lasing.

Highly versatile near-infrared emitters based on an atomically defined HgS interlayer embedded into a CdSe/CdS quantum dot.

The availability of colloidal quantum dots with highly efficient, fast and 'non-blinking' near-infrared emission would benefit numerous applications, from advanced optical communication and quantum networks to biomedical diagnostics. Here, we report high-quality near-infrared emitters that are based on well known CdSe/CdS heterostructures. By incorporating an HgS interlayer at the quantum dot core/shell interface, we convert normally visible emitters into highly efficient near-infrared fluorophores.

Long-term clinical and radiological outcomes of anterior uncoforaminotomy for unilateral single-level cervical radiculopathy: retrospective cohort study.

Background Context: Anterior cervical discectomy and fusion is a common procedure for degenerative cervical radiculopathy. In 1996, Dr. H.

Solution-processable integrated CMOS circuits based on colloidal CuInSe quantum dots.

The emerging technology of colloidal quantum dot electronics provides an opportunity for combining the advantages of well-understood inorganic semiconductors with the chemical processability of molecular systems. So far, most research on quantum dot electronic devices has focused on materials based on Pb- and Cd chalcogenides. In addition to environmental concerns associated with the presence of toxic metals, these quantum dots are not well suited for applications in CMOS circuits due to difficulties in integrating complementary n- and p-channel transistors in a common quantum dot active layer.

Exploiting Functional Impurities for Fast and Efficient Incorporation of Manganese into Quantum Dots.

The incorporation of manganese (Mn) ions into Cd(Zn)-chalcogenide QDs activates strong spin-exchange interactions between the magnetic ions and intrinsic QD excitons that have been exploited for color conversion, sunlight harvesting, electron photoemission, and advanced imaging and sensing. The ability to take full advantage of novel functionalities enabled by Mn dopants requires accurate control of doping levels over a wide range of Mn contents. This, however, still represents a considerable challenge.

Manifestation of extremely high-Q pseudo-modes in scattering of a Bessel light beam by a sphere.

The exact analytical solution of Maxwell equations for a Bessel light beam scattered by a sphere is found. Scattered power, stored energy, and a generalized factor as a function of frequency, the sphere radius, permittivity, and the Bessel beam angle are found. On the basis of this solution, modes and pseudo-modes of a dielectric sphere are extracted by calculation of the generalized factor.

Surgical treatment of neglected C2 odontoid process fracture with anterior atlantoaxial dislocation.

We report a case of the atlantoaxial (C1-2) deformity secondary to a neglected C2 odontoid fracture that was successfully treated with 3-stage operation performed in one session.

[Choice of an alternative access in failed endovascular intervention through the right radial artery].

The transradial access has deservedly become the 'gold standard' while performing various X-ray endovascular interventions both diagnostic and therapeutic ones. However, along with all its advantages, it is not without disadvantages. These difficulties for the most part are related to peculiarities of the anatomy of upper-limb arteries.

Optically pumped colloidal-quantum-dot lasing in LED-like devices with an integrated optical cavity.

Realization of electrically pumped lasing with solution processable materials will have a revolutionary impact on many disciplines including photonics, chemical sensing, and medical diagnostics. Due to readily tunable, size-controlled emission wavelengths, colloidal semiconductor quantum dots (QDs) are attractive materials for attaining this goal. Here we use specially engineered QDs to demonstrate devices that operate as both a light emitting diode (LED) and an optically pumped laser.