Cavity-mediated thermal control of metal-to-insulator transition in 1T-TaS2.

Placing quantum materials into optical cavities provides a unique platform for controlling quantum cooperative properties of matter, by both weak and strong light-matter coupling1,2. Here we report experimental evidence of reversible cavity control of a metal-to-insulator phase transition in a correlated solid-state material. We embed the charge density wave material 1T-TaS2 into cryogenic tunable terahertz cavities3 and show that a switch between conductive and insulating behaviours, associated with a large change in the sample temperature, is obtained by mechanically tuning the distance between the cavity mirrors and their alignment. The large thermal modification observed is indicative of a Purcell-like scenario in which the spectral profile of the cavity modifies the energy exchange between the material and the external electromagnetic field. Our findings provide opportunities for controlling the thermodynamics and macroscopic transport properties of quantum materials by engineering their electromagnetic environment.

Optical vortex induced spatio-temporally modulated superconductivity in a high-Tc cuprate.

We report an experimental approach to produce spatially localized photoinduced superconducting state in a cuprate superconductor using optical vortices with ultrafast pulses. The measurements were carried out using coaxially aligned three-pulse time-resolved spectroscopy, in which an intense vortex pulse was used for coherent quenching of superconductivity and the resulting spatially modulated metastable states were analyzed by the pump-probe spectroscopy. The transient response after quenching shows a spatially localized superconducting state that remains unquenched at the dark core of the vortex beam for a few picoseconds. Because the quenching is instantaneously driven by photoexcited quasiparticles, the vortex beam profile can be transferred directly to the electron system. By using the optical vortex-induced superconductor, we demonstrate spatially resolved imaging of the superconducting response and show that the spatial resolution can be improved using the same principle as that of super-resolution microscopy for fluorescent molecules. The demonstration of spatially controlled photoinduced superconductivity is significant for establishing a new method for exploring novel photoinduced phenomena and applications in ultrafast optical devices.

Charge Configuration Memory Devices: Energy Efficiency and Switching Speed.

Current trends in data processing have given impetus for an intense search of new concepts of memory devices with emphasis on efficiency, speed, and scalability. A promising new approach to memory storage is based on resistance switching between charge-ordered domain states in the layered dichalcogenide 1T-TaS2. Here we investigate the energy efficiency scaling of such charge configuration memory (CCM) devices as a function of device size and data write time τW as well as other parameters that have bearing on efficient device operation. We find that switching energy efficiency scales approximately linearly with both quantities over multiple decades, departing from linearity only when τW approaches the ∼0.5 ps intrinsic switching limit. Compared to current state of the art memory devices, CCM devices are found to be much faster and significantly more energy efficient, demonstrated here with two-terminal switching using 2.2 fJ, 16 ps electrical pulses.

Quantum jamming transition to a correlated electron glass in 1T-TaS2.

Distinct many-body states may be created under non-equilibrium conditions through different ordering paths, even when their constituents are subjected to the same fundamental interactions. The phase-transition mechanism to such states remains poorly understood. Here, we show that controlled optical or electromagnetic perturbations can lead to an amorphous metastable state of strongly correlated electrons in a quasi-two-dimensional dichalcogenide. Scanning tunnelling microscopy reveals a hyperuniform pattern of localized charges, whereas multitip surface nanoscale conductivity measurements and tunnelling spectroscopy show an electronically gapless conducting state that is different from conventional Coulomb glasses and many-body localized systems. The state is stable up to room temperature and shows no signs of either local charge order or phase separation. The mechanism for its formation is attributed to a dynamical localization of electrons through mutual interactions. Theoretical calculations confirm the correlations between localized charges to be crucial for the state's unusual stability.

The significance of angiogenesis for predicting optimal therapeutic response in chronic myeloid leukaemia patients.

In this study the correlation and the prognostic value of the morphometric parameters of angiogenesis for optimal therapeutic response to tyrosine kinase inhibitor (TKI) therapy in patients with chronic myeloid leukaemia (CML), i.e. complete cytogenetic response (CCgR) and major molecular response (MMoR), were investigated. Microvascular density (MVD) and a number of different size- and shape-related morphometric parameters of microvessels of bone marrow biopsy from 40 CML patients and 20 controls were examined. Microvessels of bone marrow were examined by using immunohistochemical staining for CD34 and quantified in the region of the most intense vascularisation by using image analysis. CML patients had significantly higher angiogenesis parameters when compared with controls. A statistically significant correlation was found between some parameters of angiogenesis and evaluated CCgR and MMoR. For achievement of CCgR, lower values of MVD, minor axis, area, circularity, and roundness and higher value of aspect ratio, while for achievement of MMoR only lower values of MVD have been identified as positive prognostic factors. Besides confirming increased angiogenesis in CML patients, this study also demonstrated prognostic significance of the degree of angiogenesis for the clinical outcome and identified angiogenic predictive factors for achieving optimal response on TKIs therapy.

Unlocking the functional properties in one-dimensional MoSI cluster polymers by doping and photoinduced charge transfer.

To improve functionalization of MoSI cluster polymers we have studied the effects of adsorption doping on the electrical transport, bundling, and optical absorption spectra. Doping results both in enhanced conductivity and aggregated bundles in dispersion. The different electronic properties of different bundle diameters can be ascribed to self-doping during the synthesis. Furthermore, doping shifts the characteristic absorption peaks and transfers oscillator strength to lower energies. Femtosecond optical spectroscopy shows that the spectral signature of adsorption and self-doping indeed originates from the population of electronic levels that are empty or absent in the undoped sample. The large spectral shifts and long lifetimes of photoinduced charges suggest efficient localization.

Alternaria-Associated Fungus Ball of Orbit Nose and Paranasal Sinuses: Case Report of a Rare Clinical Entity.

Alternaria-associated fungus ball of maxillar, ethmoidal paranasal sinuses, nasal cavity and orbit with bone erosion is extremely rare. Till recently, only two cases of this infection in immune competitive patients have been reported. We are herein describing the case of immune-competent woman who suffered of nasal congestion for 10 years. Patient was treated for tumor-like lesion in right maxillar sinus, where propagation in right nose cavity, right ethmoidal cells and right orbita was present. The organism that was seen in surgical removal of fungal debris by histological study, in using mycological testing, was proven as Alternaria alternata. Combination of surgical intervention and treatment with itraconazole eradicated fungal infection, and the disease was not relapsed in follow-up period of 2 years.

Severe dysplasia can be distinguished from moderate and mild dysplasia of bronchial mucosa by changes in Ki-67 index.

Preneoplastic lesions on small bronchial biopsy specimens may cause a diagnostic dilemma. The aim of this study was to estimate karyometric variables and the Ki-67 index of preneoplastic bronchial lesions and squamous cell carcinoma of the lung. The study was performed on endoscopic samples of squamous cell carcinoma (n = 22), normal appearing mucosa surrounding carcinoma (n = 10), bronchial dysplasia of mild (n = 7), moderate (n = 6), and severe grade (n = 6), carcinoma in situ (n = 17), and normal mucosa from patients with chronic bronchitis (n = 26). Karyometric analysis was done using the image analyzer ImageJ 1.47q. Ki-67 activity was also quantified by ImageJ 1.47q with the plugin Cell Counter. The highest values of nuclear area were found in squamous cell carcinoma, and differences were statistically significant compared to normal mucosa, all grades of dysplasia and normal appearing mucosa surrounding carcinoma (p < 0.01). The Ki-67 index was significantly higher in squamous cell lung carcinoma compared to normal mucosa, mild and moderate dysplasia and normal appearing mucosa surrounding carcinoma (p < 0.01). The Ki-67 index was significantly higher in severe dysplasia than in mild and moderate dysplasia (p < 0.01). In conclusion, the Ki-67 index is a useful parameter for more objective grading and can be of prognostic value to determine the biological potential of preneoplastic bronchial lesions.

Template synthesis of single-phase δ(3)-MoN superconducting nanowires.

We demonstrate a new and effective method of producing single-phase superconducting δ3-MoN nanowires from bundled Mo6SyIz (8.2 ≤ y + z ≤ 10) nanowire templates in the presence of ammonia gas. Magnetic susceptibility and electrical resistance measurements confirm single-phase material synthesis. Measurements of four-contact resistance on single wires with diameters above 100 nm in a magnetic field are used to determine the critical field, while diameter dependence and magnetization measurements are used to investigate the homogeneity of the nanowires.

Non-equilibrium quantum domain reconfiguration dynamics in a two-dimensional electronic crystal and a quantum annealer.

Relaxation dynamics of complex many-body quantum systems trapped into metastable states is a very active field of research from both the theoretical and experimental point of view with implications in a wide array of topics from macroscopic quantum tunnelling and nucleosynthesis to non-equilibrium superconductivity and energy-efficient memory devices. In this work, we investigate quantum domain reconfiguration dynamics in the electronic superlattice of a quantum material using time-resolved scanning tunneling microscopy and unveil a crossover from temperature to noisy quantum fluctuation dominated dynamics. The process is modeled using a programmable superconducting quantum annealer in which qubit interconnections correspond directly to the microscopic interactions between electrons in the quantum material. Crucially, the dynamics of both the experiment and quantum simulation is driven by spectrally similar pink noise. We find that the simulations reproduce the emergent time evolution and temperature dependence of the experimentally observed electronic domain dynamics.

Nanoparticles of cobalt-substituted hydroxyapatite in regeneration of mandibular osteoporotic bones.

Indications exist that paramagnetic calcium phosphates may be able to promote regeneration of bone faster than their regular, diamagnetic counterparts. In this study, analyzed was the influence of paramagnetic cobalt-substituted hydroxyapatite nanoparticles on osteoporotic alveolar bone regeneration in rats. Simultaneously, biocompatibility of the material was tested in vitro, on osteoblastic MC3T3-E1 and epithelial Caco-2 cells in culture. The material was shown to be biocompatible and nontoxic when added to epithelial monolayers in vitro, while it caused a substantial decrease in the cell viability as well as deformation of the cytoskeleton and cell morphology when incubated with the osteoblastic cells. In the course of 6 months after the implantation of the material containing different amounts of cobalt, ranging from 5 to 12 wt%, in the osteoporotic alveolar bone of the lower jaw, the following parameters were investigated: histopathological parameters, alkaline phosphatase and alveolar bone density. The best result in terms of osteoporotic bone tissue regeneration was observed for hydroxyapatite nanoparticles with the largest content of cobalt ions. The histological analysis showed a high level of reparatory ability of the nanoparticulate material implanted in the bone defect, paralleled by a corresponding increase in the alveolar bone density. The combined effect of growth factors from autologous plasma admixed to cobalt-substituted hydroxyapatite was furthermore shown to have a crucial effect on the augmented osteoporotic bone regeneration upon the implantation of the biomaterial investigated in this study.

A histological evaluation of a low-level laser therapy as an adjunct to periodontal therapy in patients with diabetes mellitus.

Diabetes mellitus (DM) and chronic periodontitis are common chronic diseases in adults in the world population. DM has a strong influence on the oral cavity and represents a risk factor for gingivitis and periodontitis. Low-level laser therapy (LLLT) has proven effective in the reduction of inflammation and swelling. The aim of the present study was to evaluate the efficacy of LLLT in diabetic periodontitis through histological analysis. A total of 300 diabetics with chronic periodontal disease and teeth indicated for extraction were assigned into six equal groups. In the groups 1 and 4, indicated teeth were extracted before treatment, and in the rest of the groups upon completion of the entire treatment. All patients received oral hygiene instructions and full-mouth conservative periodontal treatment. In groups 3 and 6, LLLT was applied (670 nm, 5 mW, 2 J/cm(2), 16 min, 5 days). Histologic findings of gingival tissue treated with LLLT showed expressed healing, as is evident by the absence of inflammatory cells. Tissue edema could not be seen, and the number of blood vessels was reduced. In the gingival lamina, propria pronounced collagenization and homogenization were present. It can be concluded that LLLT has shown efficacy in the treatment of periodontitis in diabetics. Because of more pronounced alterations of periodontium in diabetics, the use of LLLT is of particular importance.

Manipulation of fractionalized charge in the metastable topologically entangled state of a doped Wigner crystal.

Metastability of many-body quantum states is rare and still poorly understood. An exceptional example is the low-temperature metallic state of the layered dichalcogenide 1T-TaS2 in which electronic order is frozen after external excitation. Here we visualize the microscopic dynamics of injected charges in the metastable state using a multiple-tip scanning tunnelling microscope. We observe non-thermal formation of a metastable network of dislocations interconnected by domain walls, that leads to macroscopic robustness of the state to external thermal perturbations, such as small applied currents. With higher currents, we observe annihilation of dislocations following topological rules, accompanied with a change of macroscopic electrical resistance. Modelling carrier injection into a Wigner crystal reveals the origin of formation of fractionalized, topologically entangled networks, which defines the spatial fabric through which single particle excitations propagate. The possibility of manipulating topological entanglement of such networks suggests the way forward in the search for elusive metastable states in quantum many body systems.

Coherent light control of a metastable hidden state.

Metastable phases present a promising route to expand the functionality of complex materials. Of particular interest are light-induced metastable phases that are inaccessible under equilibrium conditions, as they often host new, emergent properties switchable on ultrafast timescales. However, the processes governing the trajectories to such hidden phases remain largely unexplored. Here, using time- and angle-resolved photoemission spectroscopy, we investigate the ultrafast dynamics of the formation of a hidden quantum state in the layered dichalcogenide 1T-TaS2 upon photoexcitation. Our results reveal the nonthermal character of the transition governed by a collective charge-density-wave excitation. Using a double-pulse excitation of the structural mode, we show vibrational coherent control of the phase-transition efficiency. Our demonstration of exceptional control, switching speed, and stability of the hidden state are key for device applications at the nexus of electronics and photonics.

Cytomorphometric and clinical investigation of the gingiva before and after low-level laser therapy of gingivitis in children.

Gingival epithelial cells are the first physical barrier against periodontal pathogenic microorganisms. Bacterial products may penetrate the epithelium and directly disturb its integrity. We investigated the clinical and cytomorphological status of the gingiva in children with gingivitis before and after low-level laser therapy. The study enrolled 130 children divided into three groups: group 1 comprised 50 children with chronic catarrhal gingivitis who received basic treatment, group 2 comprised 50 children with chronic catarrhal gingivitis who received low-level laser treatment in addition to basic treatment, and group 3 comprised 30 children with healthy gingiva as controls. Oral hygiene and the status of the gingiva were assessed using the appropriate indexes before and after treatment. Inflammation of the gingiva was monitored by cytomorphometric evaluation. Cytomorphometric analysis revealed a statistically significant difference (p < 0.001) in the size of the nuclei of the stratified squamous epithelial cells of the gingiva before and after treatment in chronic catarrhal gingivitis. Evaluation using clinical parameters showed that treatment of gingivitis with basic treatment was successful. Cytomorphometric analysis showed that after basic treatment the nuclei of the stratified squamous epithelial cells of the gingiva were reduced in size, although not to the size found in healthy gingiva. However, after adjuvant low-level laser therapy, the size of the nuclei of the stratified squamous epithelial cells in the gingiva matched the size of the nuclei in the cells in healthy gingiva.

Beneficial effects of calcium oral coadministration in gentamicin-induced nephrotoxicity in rats.

Frequent therapeutical use of an aminoglycoside antibiotic gentamicin (GM) is limited by its nephrotoxic effects often characterized by both morphological and functional alterations of kidney leading to acute renal failure. The aim of this study was to examine the effect of dietary calcium supplementation on GM-induced nephrotoxicity in rats. Experiments were performed on 30 adult male Wistar rats divided into three groups of 10 animals each. G-group received GM intraperitoneally at a dose of 100 mg/kg; GCa-group received the same dose of GM concomitantly with 1 g/kg calcium carbonate given orally; and C-group, serving as control, received 1 mL/day of normal saline. All groups were treated during 8 consecutive days. Quantitative evaluation of GM-induced structural and functional changes of kidney was performed by histopathological, morphometrical, and biochemical analyses. Compared with control, G-group of rats were found to have diffusely and unequally thickened glomerular basement membrane with neutrophil cells infiltration. In addition, vacuolization of cytoplasm of proximal tubule cells with coagulation-type necrosis was observed. These GM-induced pathological lesions were significantly reduced in the rats of GCa-group. Morphometric analysis revealed statistically significant differences in the size of glomeruli (area, major and minor axes, perimeter), optical density, and roundness of glomeruli (p < 0.05) between G and GCa groups. Biochemical analysis showed significant elevation in blood urea and serum creatinine concentrations, whereas potassium concentration was lowered in G-group compared with the other groups (p < 0.01). It is concluded that oral supplementation of calcium during treatment with GM resulted in significant reduction of morphological and functional kidney alterations.

Ionization energy and energy gap structure of MoSI molecular wires: Kelvin probe, ultraviolet photoelectron spectroscopy, and cyclic voltammetry measurements.

The work function W of Mo(6)S(3)I(6) molecular nanowires is determined by Kelvin probe (KP) measurements, UV photoelectron spectroscopy (UPS), and cyclic voltammetry (CV). The values obtained by all three methods agree well, giving W = 4.8 ± 0.1 eV. CV measurements also give a gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of E(g) = 1.2 ± 0.1 eV, in agreement with recent optical measurements, but in disagreement with theoretical calculations, which predict the material to be a metal. The electronic structure of Mo(6)S(3)I(6) suggests use of the material in applications such as bulk heterostructure photovoltaics and transparent electrodes and for molecular electronics devices.

Quantum billiards with correlated electrons confined in triangular transition metal dichalcogenide monolayer nanostructures.

Forcing systems through fast non-equilibrium phase transitions offers the opportunity to study new states of quantum matter that self-assemble in their wake. Here we study the quantum interference effects of correlated electrons confined in monolayer quantum nanostructures, created by femtosecond laser-induced quench through a first-order polytype structural transition in a layered transition-metal dichalcogenide material. Scanning tunnelling microscopy of the electrons confined within equilateral triangles, whose dimensions are a few crystal unit cells on the side, reveals that the trajectories are strongly modified from free-electron states both by electronic correlations and confinement. Comparison of experiments with theoretical predictions of strongly correlated electron behaviour reveals that the confining geometry destabilizes the Wigner/Mott crystal ground state, resulting in mixed itinerant and correlation-localized states intertwined on a length scale of 1 nm. The work opens the path toward understanding the quantum transport of electrons confined in atomic-scale monolayer structures based on correlated-electron-materials.

A time-domain phase diagram of metastable states in a charge ordered quantum material.

Metastable self-organized electronic states in quantum materials are of fundamental importance, displaying emergent dynamical properties that may be used in new generations of sensors and memory devices. Such states are typically formed through phase transitions under non-equilibrium conditions and the final state is reached through processes that span a large range of timescales. Conventionally, phase diagrams of materials are thought of as static, without temporal evolution. However, many functional properties of materials arise as a result of complex temporal changes in the material occurring on different timescales. Hitherto, such properties were not considered within the context of a temporally-evolving phase diagram, even though, under non-equilibrium conditions, different phases typically evolve on different timescales. Here, by using time-resolved optical techniques and femtosecond-pulse-excited scanning tunneling microscopy (STM), we track the evolution of the metastable states in a material that has been of wide recent interest, the quasi-two-dimensional dichalcogenide 1T-TaS2. We map out its temporal phase diagram using the photon density and temperature as control parameters on timescales ranging from 10-12 to 103 s. The introduction of a time-domain axis in the phase diagram enables us to follow the evolution of metastable emergent states created by different phase transition mechanisms on different timescales, thus enabling comparison with theoretical predictions of the phase diagram, and opening the way to understanding of the complex ordering processes in metastable materials.