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Renaissance of Organic Triboluminescent Materials
No full textSolid-state luminescence of organic dyes is an elusive frontier, and understanding and designing solid-state stimuli-responsive materials is not trivial. ``Mechanoluminescence'' (ML) or ``triboluminescence'' (TL), which is associated with fracture or force-initiated luminescence from a material, is currently attracting new interest. Fracturing the surfaces of organic crystals ordered in noncentrosymmetric space groups can electronically excite the surface and neighboring molecules through piezo- or pyroelectric effects, and this can result in luminescence when the molecules relax back to their ground states. The combined duration of these two consecutive phenomena leads to force-generated luminescence or TL. Although TL has been known for a very long time, examples of TL-active materials are scarce, but are increasing as synthetic and characterization procedures develop. The question is now whether the relatively rare phenomenon of TL needs to be reevaluated to obtain a broader understanding of the subject
Influence of Temperature and Strain Rate on Microstructural Evolution During Hot Compression of Ti-45Al-xNb-0.2C-0.2B Titanium Aluminide Alloys
No full textThe hot deformation response of third-generation titanium aluminides with compositions Ti-45Al-5Nb-0.2B-0.2C and Ti-45Al-10Nb-0.2B-0.2C (hereafter referred to as Ti-45-5 and Ti-45-10, respectively) has been investigated through isothermal compression tests. The tests have been carried out in the (alpha 2+gamma)\textbackslashphase regions for both alloys. The flow response, kinetics and microstructural evolution during hot deformation have been analysed in detail, and the outcome of the investigation has been used to predict the processing window for the two alloys. The optimum processing domain for the Ti-45-10 alloy is situated 50 degrees C higher than that of the Ti-45-5 alloy. The post-mortem analyses of the microstructures revealed that deformation in the (alpha 2+gamma) phase field leads to dynamic recrystallisation of all the phases resulting in a distribution of very fine grains. Microstructural features of both alloys depict kinking and breaking of the lamellae for the equivalent temperatures. The higher strength of the Ti-45-10 alloy has been attributed to shifting of the order-disorder transition toward the higher temperature side. In the (alpha+gamma) phase increases more for the Ti-45-10 alloy compared with the Ti-45-5 alloy
A Novel Ex Vivo System Using 3D Polymer Scaffold to Culture Circulating Tumor Cells from Breast Cancer Patients Exhibits Dynamic E-M Phenotypes
No full textThe majority of the cancer-associated deaths is due to metastasis-the spread of tumors to other organs. Circulating tumor cells (CTCs), which are shed from the primary tumor into the circulation, serve as precursors of metastasis. CTCs have now gained much attention as a new prognostic and diagnostic marker, as well as a screening tool for patients with metastatic disease. However, very little is known about the biology of CTCs in cancer metastasis. An increased understanding of CTC biology, their heterogeneity, and interaction with other cells can help towards a better understanding of the metastatic process, as well as identify novel drug targets. Here we present a novel ex vivo 3D system for culturing CTCs from breast cancer patient blood samples using porous poly(epsilon-caprolactone) (PCL) scaffolds. As a proof of principle study, we show that ex vivo culture of 12/16 (75%) advanced stage breast cancer patient blood samples were enriched for CTCs identified as CK+ (cytokeratin positive) and CD45- (CD45 negative) cells. The deposition of extracellular matrix proteins on the PCL scaffolds permitted cellular attachment to these scaffolds. Detection of Ki-67 and bromodeoxyuridine (BrdU) positive cells revealed proliferating cell population in the 3D scaffolds. The CTCs cultured without prior enrichment exhibited dynamic differences in epithelial (E) and mesenchymal (M) composition. Thus, our 3D PCL scaffold system offers a physiologically relevant model to be used for studying CTC biology as well as for individualized testing of drug susceptibility. Further studies are warranted for longitudinal monitoring of epithelial-mesenchymal transition (EMT) in CTCs for clinical association
Thermally evaporated Cu-Al thin film coated flexible glass mirror for concentrated solar power applications
No full textThis paper reports the development of mechanically flexible reflective coatings of Cu-Al intermetallic alloy on flexible glass (PG) substrates for possible concentrated solar power application. Thin films of Cu-Al intermetallic alloys were deposited on 100 mu m thick FG substrates using resistive thermal evaporation of arc melted Cu-Al bulk alloy. At the optimized evaporation conditions, smooth intermetallic alloy thin films with homogeneous composition (Cu0.78Al0.22) were obtained. At a coating thickness of 160 nm, average specular and total reflectance of similar to 84% and similar to 92% respectively, were achieved. The films exhibited hydrophobic nature with a contact angle of 102 degrees, implying the possibility of developing a self-cleaning ability. The analytical calculation involving alloy compositional dependence of plasma frequency reveals the prospect of further modulating the reflectance property by carefully tailoring thin film composition. Additionally, hard intermetallic thin film provides the opportunity of developing mirrors that may not require top protective coatings
NRF2 activates a partial epithelial-mesenchymal transition and is maximally present in a hybrid epithelial/mesenchymal phenotype
No full textThe epithelial-mesenchymal transition (EMT) is a key process implicated in cancer metastasis and therapy resistance. Recent studies have emphasized that cells can undergo partial EMT to attain a hybrid epithelial/mesenchymal (E/M) phenotype - a cornerstone of tumour aggressiveness and poor prognosis. These cells can have enhanced tumour-initiation potential as compared to purely epithelial or mesenchymal ones and can integrate the properties of cell-cell adhesion and motility that facilitates collective cell migration leading to clusters of circulating tumour cells (CTCs) - the prevalent mode of metastasis. Thus, identifying the molecular players that can enable cells to maintain a hybrid E/M phenotype is crucial to curb the metastatic load. Using an integrated computational-experimental approach, we show that the transcription factor NRF2 can prevent a complete EMT and instead stabilize a hybrid E/M phenotype. Knockdown of NRF2 in hybrid E/M non-small cell lung cancer cells H1975 and bladder cancer cells RT4 destabilized a hybrid E/M phenotype and compromised the ability to collectively migrate to close a wound in vitro. Notably, while NRF2 knockout simultaneously downregulated E-cadherin and ZEB-1, overexpression of NRF2 enriched for a hybrid E/M phenotype by simultaneously upregulating both E-cadherin and ZEB-1 in individual RT4 cells. Further, we predict that NRF2 is maximally expressed in hybrid E/M phenotype(s) and demonstrate that this biphasic dynamic arises from the interconnections among NRF2 and the EMT regulatory circuit. Finally, clinical records from multiple datasets suggest a correlation between a hybrid E/M phenotype, high levels of NRF2 and its targets and poor survival, further strengthening the emerging notion that hybrid E/M phenotype(s) may occupy the `metastatic sweet spot'
Black carbon physical and optical properties across northern India during pre-monsoon and monsoon seasons
No full textBlack carbon (BC) is known to have major impacts on both climate and human health and is therefore of global importance, particularly in regions close to large populations that have strong sources. The size-resolved mixing state of BC-containing particles was characterised using a single-particle soot photometer (SP2). The study focusses on the Indo-Gangetic Plain (IGP) during the pre-monsoon and monsoon seasons. Data presented are from the UK Facility for Airborne Atmospheric Measurements BAe-146 research aircraft that performed flights during the pre-monsoon (11 and 12 June) and monsoon (30 June to 11 July) seasons of 2016. Over the IGP, BC mass concentrations were greater (1.95 mu gm(-3)) compared to north-west India (1.50 mu gm(-3)) and north-east India (0.70 mu gm 3) during the pre-monsoon season. Across northern India, two distinct BC modes were recorded; a mode of small BC particles (core diameter < 0 :16 mu m and coating thickness < 50 nm) and a mode of moderately coated BC (core diameter < 0 :22 mu m and coating thickness of 50-200 nm). The IGP and north-east India locations exhibited moderately coated black carbon particles with enhanced coating thicknesses, core sizes, mass absorption cross sections, and scattering enhancement values compared to much lower values present in the north-west. The coating thickness and mass absorption cross section increased with altitude (13 %) compared to those in the boundary layer. As the monsoon arrived across the region, mass concentration of BC decreased over the central IGP and north-east locations (38% and 28% respectively), whereas for the northwest location BC properties remained relatively consistent. Post-monsoon onset, the coating thickness, core size, mass absorption cross section, and scattering enhancement values were all greatest over the central IGP much like the pre-monsoon season but were considerably reduced over both north-east and north-west India. Increases in mass absorption cross section through the atmospheric column were still present during the monsoon for the north-west and central IGP locations, but less so over the north-east due to lack of long-range transport aerosol aloft. Across the Indo-Gangetic Plain and north-east India during the pre-monsoon and monsoon seasons, solid-fuel (wood burning) emissions form the greatest proportion of BC with moderately coated particles. However, as the monsoon develops in the north-east there was a switch to small uncoated BC particles indicative of traffic emissions, but the solid-fuel emissions remained in the IGP into the monsoon. For both seasons in the north-west, traffic emissions form the greatest proportion of BC particles. Our findings will prove important for greater understanding of the BC physical and optical properties, with important consequences for the atmospheric radiative forcing of BC-containing particles. The findings will also help constrain the regional aerosol models for a variety of applications such as space-based remote sensing, chemistry transport modelling, air quality, and BC source and emission inventories
Structural determination of Enzyme-Graphene Nanocomposite Sensor Material
No full textState-of-the-art ultra-sensitive blood glucose-monitoring biosensors, based on glucose oxidase (GOx) covalently linked to a single layer graphene (SLG), will be a valuable next generation diagnostic tool for personal glycemic level management. We report here our observations of sensor matrix structure obtained using a multi-physics approach towards analysis of small-angle neutron scattering (SANS) on graphene- based biosensor functionalized with GOx under different pH conditions for various hierarchical GOx assemblies within SLG. We developed a methodology to separately extract the average shape of GOx molecules within the hierarchical assemblies. The modeling is able to resolve differences in the average GOx dimer structure and shows that treatment under different pH conditions lead to differences within the GOx at the dimer contact region with SLG. The coupling of different analysis methods and modeling approaches we developed in this study provides a universal approach to obtain detailed structural quantifications, for establishing robust structure-property relationships. This is an essential step to obtain an insight into the structure and function of the GOx-SLG interface for optimizing sensor performance
Search for supersymmetry in proton-proton collisions at 13 TeV in final states with jets and missing transverse momentum
No full textResults are reported from a search for supersymmetric particles in the final state with multiple jets and large missing transverse momentum. The search uses a sample of proton-proton collisions at root s = 13 TeV collected with the CMS detector in 2016-2018, corresponding to an integrated luminosity of 137 fb(-1), representing essentially the full LHC Run 2 data sample. The analysis is performed in a four-dimensional search region defined in terms of the number of jets, the number of tagged bottom quark jets, the scalar sum of jet transverse momenta, and the magnitude of the vector sum of jet transverse momenta. No significant excess in the event yield is observed relative to the expected background contributions from standard model processes. Limits on the pair production of gluinos and squarks are obtained in the framework of simplified models for supersymmetric particle production and decay processes. Assuming the lightest supersymmetric particle to be a neutralino, lower limits on the gluino mass as large as 2000 to 2310 GeV are obtained at 95% confidence level, while lower limits on the squark mass as large as 1190 to 1630 GeV are obtained, depending on the production scenario
Simultaneous Small Noise Limit for Singularly Perturbed Slow-Fast Coupled Diffusions
No full textWe consider a simultaneous small noise limit for a singularly perturbed coupled diffusion described by where B-t, W-t are independent Brownian motions on R-d and R-m respectively, b : R-d xR(m) -> R-d, U : R-d xR(m) -> R and s : (0, infinity) -> (0, infinity). We impose regularity assumptions on b, U and let 0 < alpha < 1. When s(e) goes to zero slower than a prescribed rate as epsilon -> 0, we characterize all weak limit points of X-epsilon, as epsilon -> 0, as solutions to a differential equation driven by a measurable vector field. Under an additional assumption on the behaviour of U(x, center dot) at its global minima we characterize all limit points as Filippov solutions to the differential equation
Search for the associated production of the Higgs boson and a vector boson in proton-proton collisions at=13 TeV via Higgs boson decays to leptons
No full textA search for the standard model Higgs boson produced in association with a W or a Z boson and decaying to a pair of leptons is performed. A data sample of proton-proton collisions collected at p s = 13TeV by the CMS experiment at the CERN LHC is used, corresponding to an integrated luminosity of 35.9 fb. The signal strength is measured relative to the expectation for the standard model Higgs boson, yielding = 2: 5 +1:4. These results are combined with earlier CMS measurements targeting Higgs boson decays to a pair of leptons, performed with the same data set in the gluon fusion and vector boson fusion production modes. The combined signal strength is = 1: 24 +0:29 (1: 00 +0:24 expected), and the observed signi fi cance is 5.5 standard deviations (4.8 expected) for a Higgs boson mass of 125GeV