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This paper presents an efficient polynomial chaos expansion approach for structural uncertainty analysis in conjunction with the multiplicative dimensional reduction method. The development of a standard polynomial chaos expansion model needs to evaluate a large number of multivariate integrals for the expansion coefficient. The utility of the multiplicative dimensional reduction approach is able to approximate the multivariate integral as the product of univariate and bivariate expectations. Together with the standard Gauss-quadrature scheme for accurate low-variate integration results, an effective polynomial chaos expansion model is proposed to mimic the true performance function for structural uncertainty analysis. Since only dimensionally reduced univariate and bivariate component functions are involved, the proposed algorithm is able to overcome the curse of dimensionality problem in the ordinary polynomial chaos expansion procedure. Engineering applications of the proposed approach are demonstrated by several structural reliability and reliability-based design optimization problems in the literature. Compared to benchmark results provided by the brutal force Monte Carlo simulation, the high accuracy and efficiency of the multiplicative dimensional reduction–based polynomial chaos expansion algorithm have justified its potential applications for various structural uncertainty problems.

Hand gesture recognition applied in human-computer interaction (HCI) is a useful but challenging task because of the low inter-class and high intra-class variability. It is difficult to improve real-time performance while ensuring accuracy. Since simple but robust features are crucial for the performance of recognition, we proposed the weighted depth difference motion history image (WDD-MHI) to extract spatial-temporal information. Subsequently, a weighted random forest classifier with second training is employed for action classification. The developed method is shown to be computationally efficient allowing it to run in real-time. We designed a multimedia video-wall control system based on online gesture recognition, the recognition results indicate competitive performance of our method over the other methods.

Background and aims We previously demonstrated that cancer-associated fibroblasts (CAFs) promote tumor growth via recruiting of myeloid-derived suppressor cells (MDSCs). 5-lipoxygenase (5-LO) is highly expressed in myeloid cells and critical for synthesizing leukotriene B4 (LTB4), which is involved in tumor progression via acting its receptor Leukotriene B4 receptor type 2 (BLT2). In this study, we investigated whether and how CAFs regulate MDSC function to enhance cancer stemness, the driving force of the cancer aggressiveness and chemotherapy refractoriness, in highly desmoplastic intrahepatic cholangiocarcinoma (ICC). Approach and results RNA-sequencing analysis revealed enriched metabolic pathways but decreased inflammatory pathways in cancer MDSCs compared with blood MDSCs from ICC patients. Co-injection of ICC patient-derived CAFs promoted cancer stemness in an orthotopic ICC model, which was blunted by MDSC depletion. Conditioned media (CM) from CAF-educated MDSCs drastically promoted tumorsphere formation efficiency and stemness marker gene expression in ICC cells. CAF-CM stimulation increased expression and activity of 5-LO in MDSCs while 5-LO inhibitor impaired the stemness-enhancing capacity of MDSCs in vitro and in vivo. Furthermore, IL-6 and IL-33 mainly expressed by CAFs mediated hyperactivated 5-LO metabolism in MDSCs. We identify the LTB4-BLT2 axis as the critical downstream metabolite signaling of 5-LO in promoting cancer stemness, as treatment with LTB4 that were elevated in CAF-educated MDSCs or blockade of BLT2 that was preferentially expressed in stem-like ICC cells significantly reduced stemness-enhancing effects of CAF-educated MDSCs. Finally, BLT2 blockade augmented chemotherapeutic efficacy in ICC patient derived-xenograft (PDX) models. Conclusions Our study reveals a previously unrecognized role for CAFs in orchestrating the optimal cancer stemness-enhancing microenvironment by educating MDSCs and suggests 5-LO/LTB4-BLT2 axis as promising therapeutic targets for ICC chemoresistance by targeting cancer stemness.

Polymers : Molecular Diversity Preservation International 13(7), 1083 (2021). doi:10.3390/polym13071083 special issue: "Special Issue "Recycling and Resource Recovery from Polymers" / Special Issue Editors: Dr. Sheila Devasahayam, Guest Editor; Prof. Dr. Raman Singh, Guest Editor; Prof. Dr. Vladimir Strezov, Guest Editor", Published by MDPI, Basel

Bismuth (Bi)-doped laser materials have emerged as an attractive gain medium for the development of a new generation of fiber lasers and optical amplifiers because of their superior broadband near-infrared (NIR) luminescence covering the entire optical communication window. For their practical applications, the thermal response of laser materials should be considered. However, to the best of our knowledge, Bi NIR emission usually involves severe thermal degradation due to the easy conversion between various Bi species. In this study, we have investigated the thermal degradation properties of Bi NIR emission in the Al2O3–GeO2 glass system with different compositions and interpreted their dependencies in terms of their microscopic topological network structure. As a result, thermal degradation was entirely suppressed via a polymerized glass network structure. The addition of Li2O caused a serious thermal degradation of Bi NIR emission along with the depolymerization of the glass network structure, as revealed by the Fourier-transform infrared (FTIR) and 27Al nuclear magnetic resonance (NMR) spectra. When Mg ions replaced Li ions, thermal degradation efficiently weakened. This may be attributed to the fact that depolymerization was significantly suppressed by introducing Mg–O– into the network structure units. In order to prevent the depolymerization of the glass network structure, we introduced trace amounts of Bi2O3 as both network modifiers and active ions in the glass system. Correspondingly, the thermal degradation of Bi NIR emission was completely inhibited. This study resolves the problem of thermal degradation of Bi NIR emission in glasses, and it can facilitate the design of Bi-doped laser glasses with stable luminescence properties and for the fabrication of fibers in the future.

Bi-Doped photonic materials with broadband near infrared (NIR) photoemission have allowed rapid progress of new-generation fiber lasers and super-broadband optical amplifiers. Despite this, major challenges persist towards realizing super-broad and efficient Bi NIR emission covering the whole telecommunication window due to the complicated luminescence behavior, especially for glasses doped with a low Bi content. Here, via introducing nitride into glasses, we obtained super-broad and highly reinforced NIR emission in multi-component borogermanate glasses, which resulted from the generation of multiple Bi NIR-active centers. The spectral bandwidth exceeded ∼600 nm; this enabled Bi-activated glasses to cover the whole NIR region (850–1700 nm), which can hardly be realized by quantum-dot-doped glasses, rare earth-functionalized glasses or current Bi-doped multi-component photonic glasses. A detailed analysis of the spectra and tailoring of local glass structures revealed that the compact glass structure with the addition of antimony oxide and the bonding effect of nitrogen could contribute to significant increase in the Bi NIR emission intensity and decay lifetime. The newly generated Bi luminescent centers may have originated from the low-valence Bi effected by oxygen vacancies. These results will add new knowledge to the luminescence behaviors of Bi and may help solve the current limitations of Bi-doped glass and fiber materials. Moreover, the nitridation of materials may offer a way to fundamentally boost luminescence efficiency, especially for ultra-low activator content.

The emerging era of big data has stimulated the development of optical materials with broad emission region to allow data transmission of higher capacity and speed. Here, broadband emission, almost covering the region of 650–1500 nm, was realized by doping transition metal ions into versatile aluminate glasses, in which abundant microstructures and certain oxidizing capacity could be guaranteed to enrich emissions. Furthermore, we aimed to improve spectroscopic properties via the simultaneous self-redox and crystal field modulation of Cr ions and matrixes, respectively. More emission ions and more efficient centers were created to enhance the emission intensity by more than one order of magnitude. In addition, proper crystal field was created to liberate a new emission band at ∼708 nm. The results may allow the development of tunable fiber laser and amplifier using the materials and pave the way to precisely control the valence and crystal field to obtain efficient emission.

On the premise of solving the problem in a specific situation, this paper aims at the laser marking machine for the design and optimization of the outline extraction of the two-dimensional composite curve figure and the figure hatching scheme. The scanning line algorithm based on computer graphics and the polygon hatching are based on the algorithm theory. Based on the foundation, an improved polygon scan line algorithm model is established, and the contour extraction and graphic shadows of two-dimensional polygons are realized by MATLAB programming. The simulation results show that our algorithm model can meet our requirements well, and at the same time has a certain improvement effect. At the same time, compared with traditional two-dimensional polygon scanning and hatching algorithms, our algorithm model has strong analysis and processing capabilities and strong applicability. Compared with traditional two-dimensional polygon scanning and shading algorithms, model analysis can still run stably in a high refresh rate environment. We hope to further optimize the algorithm in the later stage, so that it can be better used in related engineering fields.

Unlike the many transition metal ions- and rare earth ions-doped long persistent materials, at present, few bismuth ion-doped long persistent materials have been reported. In this work, we report on a novel phosphor Sr3Ga4O9:Bi3+ that combines photoluminescence, long persistent luminescence and triboluminescence at room temperature. The compound glows in the green (530 nm) and red (680 nm) spectral regions upon excitation in the range 240–400 nm. From calculation results based on the original theory of electronegativity, we obtain the energy level structure of Bi3+ (doped into Sr sites 1–3) in Sr3Ga4O9:Bi3+, from which it is inferred that these emissive features are ascribed to Bi3+ pairs. These emissions are also produced under mechanical action and show a persistence up to 6.5 hours after removal of ultraviolet super-bandgap irradiation. This is the first observation of such multi-functionality for an inorganic solid activated with Bi3+. Furthermore, considering our insights into the elusive nature of Bi3+ luminescence, we expect that the Bi3+-doped mechanoluminescence (ML) material will further promote the development of ML.

The generation of optical afterglow and comprehension of the structure–function mechanism in glasses have not been well studied to date owing to the uncertainty of internal structure and defects, let alone being able to tailor the afterglow. Herein, we fabricate a new type of Mn2+-doped calcium aluminium germanate photonic glasses that demonstrate red to near-infrared persistent luminescence from 560 to 820 nm. Provoked by the understanding of amorphous structure continuity, facile network topology was utilized as a tuning strategy, resulting in modulation of the persistent luminescence time from 30 min to longer than 24 h. The density of correlative electronic defects increases with their depth gradually deepening from 0.69, 0.78, and 0.83 eV to 0.80, 0.85, and 0.90 eV. Multiple measurements reveal that the internal structure evolves towards regular crosslinking, promoting the incorporation and stabilization of Mn2+ along with the change of defects, all of which are conducive to afterglow. The possible attribution of defects stems not only from the structural intrinsic state, but also from defects caused by the photo-oxidation of Mn2+. Coupled with their association to afterglow, the mechanism of persistence regulation is expounded in detail, and its potential applications in displays and in vivo imaging are demonstrated. This work suggests accessible references to the rational design of persistent materials with flexible persistence or even other advantageous functions.

Human detection is a critical measure used for obtaining the information of flow density in a region, of which the data is conductive to the customer flow analysis for some businesses, avoiding human stampedes caused by excessive people simultaneously. Although previous research into human detection is generally based on a 2D camera, the data collected by it is vulnerable to pedestrian occlusion, complex background, shadow interference, and other uncontrollable factors. Meanwhile, human detection algorithms based on 3D are also studied currently by some researchers, however, these methods suffer from low efficiency and high error rate. Thus, a novel real-time human detection algorithm based on the ToF camera is proposed in this paper. Different from other detection algorithms running on the computer, our algorithm is implemented on an embedded 3D camera platform. This method is divided into two steps to go on: firstly, the novel detection algorithm determines the head position by finding the peak value for the region of interest (ROI). Secondly, combined with an improved Hungarian algorithm and a prediction of human movements using a Kalman filtering which facilitates the tracking rate significantly. The experimental results demonstrate that the accuracy of the novel algorithm in real-time people detecting and tracking is above 95%.

In current work, iron doping Co3O4 (Fe/Co3O4) mesoporous nanosheets with different iron ratios were successfully prepared to degrade P-nitrophenol (PNP) via peroxymonosulfate (PMS) activation. The obtained optimal 0.15Fe/Co3O4 exhibited the best PMS activation performance, almost 100% of PNP can be removed at pH = 5.5 in 60 min with negligible Co leaching. The excellent PMS activation performance of 0.15Fe/Co3O4 was mainly attributed to the enhanced electron transfer efficiency of Co2+/Co3+ and Fe2+/Fe3+ cycles and abundant oxygen vacancies, which benefiting in promoting more hydroxyl radical (•OH), sulfate radical (SO4•−), and singlet oxygen (1O2) generation. And the intimate relationship between PNP degradation efficiency and the contents of Co2+, Fe2+, Ovac in xFe/Co3O4 was obseved. Meanwhile, the mechanism for improved PMS activation efficiency was proposed based on ROSs quenching, XPS, and ESR results. In addition, the degradation pathway of PNP was explored based on the intermediates determined via the gas chromatography-mass spectrometer (GC-MS). This study can provide an effective strategy to obtain Co based catalysts with excellent PMS activation for recalcitrant pollutants degradation.

The blue-emitting phosphor Ba5(BO3)2(B2O5):Ce3+ was synthesized by a high-temperature solid-state method. Its crystal structure, luminescence properties, concentration-quenching mechanism and thermal stability were investigated. This phosphor can be effectively excited by 351-nm near-ultraviolet light, with a broad blue emission band. The emission spectra of the Ba5(BO3)2(B2O5):Ce3+ phosphor were clearly monitored with critical emission quenching as a function of the Ce3+ content. It was further proven that the energy transfer among the nearest-neighbor ions results in the concentration quenching of Ce3+ in Ba5(BO3)2(B2O5). The dependence of the luminescent intensity on the charge-compensated (Li+, Na+, K+) was also discussed. Ba5(BO3)2(B2O5):Ce3+ phosphors can be effectively excited by near-UV light and simultaneously exhibit excellent luminescence resistibility against thermal quenching in the temperature range from 300 to 400 K. The activation energy ΔE is calculated to be 0.21 eV. The present work suggests that the Ba5(BO3)2(B2O5):Ce3+ phosphor is a promising material for near-UV chip-based white LEDs.

Increasingly rigorous temperature detection applied to characterize physico-chemical state has stimulated thriving demands for contactless optical thermometry, which must overcome obstacles of complex preparation, low sensitivity, poor stability and inflexible design. Herein, a new optical thermal-sensitive LaTiSbO6:Mn4+ and its upgraded engineering frameworks are firstly constructed and systematically analyzed. The title phosphor exhibits specific single-band narrow emission (FWHM = ~31 nm) in deep-red region centered at 683 nm and superior thermal-sensitivity (SR = 2.75% K−1, 298–418 K) based on reliable fluorescence lifetime mode. Outstanding robustness of the phosphor concluded from aging experiment highlights the prerequisites of its practical duration and functional independence in diversified architecture. Through phosphor-in-glass (PiG) strategy, robust products are controllably organized without ascertainable interfacial reaction between introduced particles and glass matrix, yielding intriguing improved performance (SR = 3.01% K−1) inherited from LaTiSbO6:Mn4+. Moreover, fabricated heterogeneous PiG architecture, spatially confining LaTiSbO6:Mn4+ and YAG:Ce3+ to block unfavorable energy-transfer depletion, facilely accomplish dual-mode thermometry without significant mutual interference, integrating the Mn4+-lifetime and highly recyclable fluorescence intensity ratio (FIR) from the Ce–Mn non-thermally-coupled system. This work not only suggests LaTiSbO6:Mn4+ as a promising candidate, but also expands new horizons with the topological composite pathway toward rational designing and perfecting multi-mode thermometer or other versatile constructions.

A novel route toward tunable multicolor materials through phosphor-in-glass (PiG) technology is proposed in this work. Before that, an ultrastable Eu3+-doped precursor luminescent glass frit without thermal quenching in the temperature range of 80–480 K is developed to serve as an encapsulant that not only protects the embedded phosphor but also provides the red-emitting component for the PiG. By adjusting the mass ratio of Sr4Al14O25:Eu2+ phosphor to glass frit, a series of tunable multicolor Eu3+-doped PiG is obtained and exhibits a good resistance to the harsh conditions. Meanwhile, the luminescent color of Eu3+-doped PiG can be modified by changing the excitation wavelength or ambient temperature. Finally, corresponding Eu3+-doped PiG encapsulated high-power light-emitting diodes are further fabricated, especially the warm white-light-emitting diodes (WLEDs), showing good color stability under different drive currents and with different periods of operating time. All these results indicate that Eu3+-doped PiG is a potential color converter applied in the high-power warm-WLEDs and the route above opens up a facile and potential approach to obtain multicolor materials.