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Electrochemical and optical properties of a new class of electrochromic 3-aryl-4,5-bis (pyridin-4-yl)isoxazoles derivatives containing conjugated pyridine fragments were investigated comparing with their precursor 1,2-bis(4-pyridinyl)ethylene derivative. Electrochromic cells based on synthesized substances were reversibly colored in brown upon the application of a voltage of 1.5 V.

The approaches to the synthesis of new derivatives of 2-7-dibromofluorene and benzocyclobutene have been investigated. For this purpose 9-bicyclo [4.2.0] octa-1 (6), 2,4- trien-3-yl-2,7-dibromo-9H-fluoren-9-ol was synthesized by reaction of 2,7-dibromo-fluoren -9- one with 3-benzocyclobutene magnesium bromide. The possibility of reduction and substitution of the hydroxyl group at position 9 of the obtained compound with aromatic substituents under conditions of acid catalysis is demonstrated. Target compounds were obtained in yields from 75 to 90%.

New cross-linking monomer based on 1,3-diallyl-1,3-di[bicyclo[4.2.0]octa-1,3,5-trien-3-yl]-1,3-dimethyl-siloxane (BCB-All) was synthesized and its physical properties were studied. BCB-All was incorporated into copolymer with TGM-3 and PFHDA by two stage thermal polymerization. The cross-linking of the copolymers occurs by thermo-initiated ring-opening reaction of BCB at 120-200°C. Resulting BCB-All homopolymer, BCB-All-TGM-3 (50:50), and BCB-All-PFHDA (50:50) copolymers have high thermal stability (Td5%,=464°C, 322°C, 435°C respectively) and good dielectric properties (ε=2.34-2.48 at 10HHz).

The physical limitations of the amount of data stored on optical media are pushing researchers to create new materials and methods for recording and reading data. One of the promising areas is the use of fluorescent compounds. Within the framework of this work, polymer structures of optical fluorescent memory with a recording medium based on 3-(thiophene-2-carbonyl) -2- (furan-2-yl) -4n-chromen-4-one in polymethylmethacrylate have been fabricated and investigated. The concentration of chromone was 5% (wt.), Which during recording made it possible to achieve optical density values at λ = 442 nm in the range of 0.01 - 0.02 with a central layer thickness of 1-3 µm. In the structures developed, the process of two-photon information recording and fluorescent parallel reading is realized. The threshold recording power density for providing a two-photon process was (5.1 ± 0.4) 105 W/cm2.

In long-term follow-up of more than 500 patients with melanoma containing a BRAF V600E or V600K mutation, a combination of dabrafenib plus trametinib was associated with progression-free survival in 19% of the patients and overall survival in 34% at 5 years. A complete response to dabrafenib plus trametinib was the strongest predictor of long-term survival.

Unconventional superconductivity often emerges in close proximity to a magnetic instability. Upon suppressing the magnetic transition down to zero temperature by tuning the carrier concentration, pressure, or disorder, the superconducting transition temperature Tc acquires its maximum value. A major challenge is the elucidation of the relationship between the superconducting phase and the strong quantum fluctuations expected near a quantum phase transition (QPT) that is either second order (i.e. a quantum critical point) or weakly first order. While unusual normal state properties, such as non-Fermi liquid behavior of the resistivity, are commonly associated with strong quantum fluctuations, evidence for its presence inside the superconducting dome are much scarcer. In this paper, we use sensitive and minimally invasive optical magnetometry based on NV-centers in diamond to probe the doping evolution of the T = 0 penetration depth in the electron-doped iron-based superconductor Ba(Fe1−xCox)2As2. A non-monotonic evolution with a pronounced peak in the vicinity of the putative magnetic QPT is found. This behavior is reminiscent to that previously seen in isovalently-substituted BaFe2(As1−xPx)2 compounds, despite the notable differences between these two systems. Whereas the latter is a very clean system that displays nodal superconductivity and a single simultaneous first-order nematic-magnetic transition, the former is a charge-doped and significantly dirtier system with fully gapped superconductivity and split second-order nematic and magnetic transitions. Thus, our observation of a sharp peak in λ(x) near optimal doping, combined with the theoretical result that a QPT alone does not mandate the appearance of such peak, unveils a puzzling and seemingly universal manifestation of magnetic quantum fluctuations in iron-based superconductors and unusually robust quantum phase transition under the dome of superconductivity.

The physics of the crossover between weak-coupling Bardeen–Cooper–Schrieffer (BCS) and strong-coupling Bose–Einstein condensate (BEC) limits gives a unified framework of quantum-bound (superfluid) states of interacting fermions. This crossover has been studied in the ultracold atomic systems, but is extremely difficult to be realized for electrons in solids. Recently, the superconducting semimetal FeSe with a transition temperature T c =8.5 K has been found to be deep inside the BCS–BEC crossover regime. Here we report experimental signatures of preformed Cooper pairing in FeSe, whose energy scale is comparable to the Fermi energies. In stark contrast to usual superconductors, large non-linear diamagnetism by far exceeding the standard Gaussian superconducting fluctuations is observed below T *∼20 K, providing thermodynamic evidence for prevailing phase fluctuations of superconductivity. Nuclear magnetic resonance and transport data give evidence of pseudogap formation at ∼ T *. The multiband superconductivity along with electron–hole compensation in FeSe may highlight a novel aspect of the BCS–BEC crossover physics. The crossover between the weak-coupling limit and strong-coupling limit provides important information for quantum bound states of interacting fermions. Here, Kasahara et al . report thermodynamic evidence for prevailing phase fluctuations of superconductivity, highlighting unusual normal state in the BCS-BEC crossover regime.

A solid tumor is an organ composed of cancer and host cells embedded in an extracellular matrix and nourished by blood vessels. A prerequisite to understanding tumor pathophysiology is the ability to distinguish and monitor each component in dynamic studies. Standard fluorophores hamper simultaneous intravital imaging of these components. Here, we used multiphoton microscopy techniques and transgenic mice that expressed green fluorescent protein, and combined them with the use of quantum dot preparations. We show that these fluorescent semiconductor nanocrystals can be customized to concurrently image and differentiate tumor vessels from both the perivascular cells and the matrix. Moreover, we used them to measure the ability of particles of different sizes to access the tumor. Finally, we successfully monitored the recruitment of quantum dot–labeled bone marrow–derived precursor cells to the tumor vasculature. These examples show the versatility of quantum dots for studying tumor pathophysiology and creating avenues for treatment.

The addition of a MEK inhibitor to a BRAF inhibitor improved response rates by nearly 16 percentage points (from 51% to 67%) and improved progression-free survival by 0.5 months (from 8.8 to 9.3 months). Targeted inhibition of the RAF–MEK–ERK (MAPK) pathway with BRAF inhibitors dabrafenib or vemurafenib, as compared with chemotherapy, improves the progression-free and overall survival of patients who have metastatic melanoma with BRAF V600 mutations. 1 , 2 However, resistance develops in a majority of patients, resulting in a median progression-free survival of 6 to 7 months. 3 , 4 Most reported resistance mechanisms reactivate the MAPK pathway. 5 – 7 In addition, BRAF-inhibitor–induced paradoxical activation of the MAPK pathway 8 – 10 can result in secondary cancers, including cutaneous squamous-cell carcinoma, and may reactivate RAS-mutant tumors. 11 – 13 Independently, single-agent trametinib, a MEK inhibitor, improves the overall survival of patients . . .

Bacterial biofilms represent an important medical problem; however, the mechanisms of the onset of biofilm formation are poorly understood. Here, using new controlled methods allowing high-throughput and reproducible biofilm growth, we show that biofilm formation is linked to self-imposed mechanical stress. In growing uropathogenic Escherichia coli colonies, we report that mechanical stress can initially emerge from the physical stress accompanying colony confinement within micro-cavities or hydrogel environments reminiscent of the cytosol of host cells. Biofilm formation can then be enhanced by a nutrient access-modulated feedback loop, in which biofilm matrix deposition can be particularly high in areas of increased mechanical and biological stress, with the deposited matrix further enhancing the stress levels. This feedback regulation can lead to adaptive and diverse biofilm formation guided by the environmental stresses. Our results suggest previously unappreciated mechanisms of the onset and progression of biofilm growth. Bacterial biofilms are an increasingly important medical problem but the mechanisms by which they develop remain largely unknown. Here, using a high-throughput approach, the authors show that biofilm formation is linked to self-imposed mechanical stress.