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The amino-functionalization alters the microenvironment over three-dimensional nanosized mesoporous silica spheres, which is beneficial to stabilize and disperse Cu clusters. The catalyst delivers a high performance for the hydrogenation of levulinic acid into γ-valerolactone, achieving a maximum yield of 98% at relatively mild conditions. [Display omitted] • Ultrafine Cu clusters confined into amino-functionalized NMSSs were developed. • The surface amino functionalization is critical to immobilizing Cu clusters. • A prominent LA hydrogenation activity with GVL yield of 98% was achieved. • This work unlocks the potential of Cu cluster catalyst in biomass valorization. The development of noble-metal-free catalysts for upgrading biomass feedstocks to chemicals and fuels remains a crucial and challenging target. Catalytic hydrogenation of biomass-derived levulinic acid (LA) to γ-valerolactone (GVL) is one of the essential reactions for biomass valorization. Herein, we report a confined Cu cluster catalyst, Cu/NMSSs-NH 2 , in which ultrafine Cu nanoclusters are uniformly encapsulated in the channels of amino-functionalized nanosized mesoporous silica spheres (NMSSs-NH 2). The surface amino functionalization of NMSSs plays a critical role in dispersing and stabilizing Cu species. The obtained Cu/NMSSs-NH 2 affords an excellent LA hydrogenation performance, with a GVL yield as high as 98% achieved, much higher than that of unconfined Cu particles in pristine NMSSs (Cu/NMSSs, 42%). Comprehensive characterization studies including X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy reveal that the modified microenvironment of NMSSs could not only offer a confined space but also induce an electronic interaction between metal species and the support, which effectively restrains the Cu nanoclusters from aggregation. This study unlocks the potential of inexpensive Cu cluster-based catalysts for the hydrogenation of renewable biomass to high-value chemicals. [ABSTRACT FROM AUTHOR]

Cerium-based metallic glasses are prototype polyamorphous systems with pressure-induced polyamorphic transitions extensively reported. Cooling typically has a similar effect on materials as compression with regard to reducing volume. However, previous studies show dramatically different behavior of Ce-based metallic glasses between cooling and compression, whose origin remains unclear. Here, using in situ low-temperature synchrotron high-energy x-ray diffraction, the structural evolution of a Ce68Al10Cu20Co2 metallic glass is accurately determined and analyzed by a structure factor and a reduced pair distribution function (PDF) during cooling from 298 to 83 K. An unusually large linear thermal expansion coefficient is revealed, which is associated with both continuous but inconsistent structural changes between the two subpeaks of the first atomic shell in terms of average bond lengths and coordination numbers. These phenomena are suggested to be attributed to a gradual 4f electron delocalization of only a minimal amount (∼2.6% at 83 K) of Ce atoms by quantitative analysis of the PDF data. However, a previously expected global polymorphic transition from a low-density amorphous state to a high-density amorphous state with an abrupt volume collapse is not observed. Moreover, electrical resistivity also shows a continuous increase during cooling without any sharp change. It is clarified that cryogenic temperatures could facilitate but are not powerful enough alone to trigger a global polymorphic transition in the Ce68Al10Cu20Co2 metallic glass, suggesting a wide distribution of its local atomic environment. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the incorporation of pretherapy regional ventilation function in predicting radiation fibrosis (RF) in stage III nonsmall cell lung cancer (NSCLC) patients treated with concurrent thoracic chemoradiotherapy. Methods: Thirty-seven patients with stage III NSCLC were retrospectively studied. Patients received one cycle of cisplatin-gemcitabine, followed by two to three cycles of cisplatin-etoposide concurrently with involved-field thoracic radiotherapy (46-66 Gy; 2 Gy/fraction). Pretherapy regional ventilation images of the lung were derived from 4D computed tomography via a density change-based algorithm with mass correction. In addition to the conventional dose-volume metrics (V20, V30, V40, and mean lung dose), dose-function metrics (fV20, fV30, fV40, and functional mean lung dose) were generated by combining regional ventilation and radiation dose. A new class of metrics was derived and referred to as dose-subvolume metrics (sV20, sV30, sV40, and subvolume mean lung dose); these were defined as the conventional dose-volume metrics computed on the functional lung. Area under the receiver operating characteristic curve (AUC) values and logistic regression analyses were used to evaluate these metrics in predicting hallmark characteristics of RF (lung consolidation, volume loss, and airway dilation). Results: AUC values for the dose-volume metrics in predicting lung consolidation, volume loss, and airway dilation were 0.65-0.69, 0.57-0.70, and 0.69-0.76, respectively. The respective ranges for dose-function metrics were 0.63-0.66, 0.61-0.71, and 0.72-0.80 and for dose-subvolume metrics were 0.50-0.65, 0.65-0.75, and 0.73-0.85. Using an AUC value = 0.70 as cutoff value suggested that at least one of each type of metrics (dose-volume, dose-function, dose-subvolume) was predictive for volume loss and airway dilation, whereas lung consolidation cannot be accurately predicted by any of the metrics. Logistic regression analyses showed that dose-function and dose-subvolume metrics were significant (P values = 0.02) in predicting volume airway dilation. Likelihood ratio test showed that when combining dose-function and/or dose-subvolume metrics with dose-volume metrics, the achieved improvements of prediction accuracy on volume loss and airway dilation were significant (P values = 0.04). Conclusions: The authors' results demonstrated that the inclusion of regional ventilation function improved accuracy in predicting RF. In particular, dose-subvolume metrics provided a promising method for preventing radiation-induced pulmonary complications. [ABSTRACT FROM AUTHOR]

A regional water supply system design problem that determines pipe and pump design parameters and water flows over a multi-year planning horizon is considered. A non-convex nonlinear model is formulated and solved by a branch-and-reduce global optimization approach. The lower bounding problem is constructed via a three-pronged effort that involves transforming the space of certain decision variables, polyhedral outer approximations, and the Reformulation Linearization Technique (RLT). Range reduction techniques are employed systematically to speed up convergence. Computational results demonstrate the efficiency of the proposed algorithm; in particular, the critical role range reduction techniques could play in RLT based branch-and-bound methods. Results also indicate using reclaimed water not only saves freshwater sources but is also a cost-effective non-potable water source in arid regions. Supplemental data for this article can be accessed athttp://dx.doi.org/10.1080/0305215X.2015.1016508. [ABSTRACT FROM AUTHOR]

In this paper, we propose a scenario-based robust optimization model for the design of a water supply system considering the risk of facility failure, which is represented as an uncertainty set generated by a finite set of scenarios. New facilities are planned to be built to hedge against the possible failure of existing system facilities that would potentially damage the capacity of the system to meet given user demands. The goal is to build facilities that are both cost-effective and make the system robust. The system robustness is defined as the ability to satisfy user demands for every data realization in the uncertainty set. The proposed model is shown to be equivalent to a large-scale mixed-integer linear program that is solved by a Benders decomposition algorithm. Computational results demonstrate the efficiency of the proposed algorithm, and show that substantial improvement in system robustness can be achieved with minimal increase in system cost. [ABSTRACT FROM AUTHOR]

The as-prepared Cu/NC@SBA-15 composites are highly active for the hydrogenation of levulinic acid to γ-valerolactone, giving a maximum yield as high as 92 % at 140 ºC in a continuous-flow fixed-bed reactor. [Display omitted] • Fine Cu clusters anchored on g-C 3 N 4 nanoconfined into SBA-15 were developed. • The defect N sites were crucial to anchor and disperse Cu nanoclusters. • An excellent GVL yield of 92 % was achieved, comparable to that of the Ru/AC. • DFT revealed that the reaction barrier of the nanoconfined Cu clusters was reduced. • The anchoring strategy prevents the sintering of Cu clusters during the reaction. The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is a common reaction that is critical to biomass transformation. However, it is a great challenge to employ non-noble metal catalysts in realizing highly effective conversion from LA to GVL. Herein, we report an efficient strategy for anchoring highly active copper nanocluster catalysts on the defect sites of graphitic carbon nitride (g-C 3 N 4) and dispersing in mesoporous silica (SBA-15). The combination of g-C 3 N 4 and SBA-15 stabilized the copper clusters, leading to a high GVL yield of 92 % and excellent stability in 100 h. This result is comparable to that of the Ru/AC catalyst but much more economically favorable. Density functional theory calculations revealed that the reaction barrier of the new catalyst was reduced from 1.93 to 1.12 eV compared with those of unconfined copper particles. This research provides a simple anchoring strategy for constructing highly active and inexpensive copper nanocluster catalysts. [ABSTRACT FROM AUTHOR]

Structural heterogeneity has been proposed as a key intrinsic feature and mechanism underline unique properties and dynamic behavior of metallic glasses; however, it is still challenging in precisely describing and effectively characterizing the atomic-scale heterogeneity in metallic glasses. In this work, we employed the Meissner effect of superconductivity in magnetic susceptibility measurements as a sensitive bulk probe and successfully revealed the three-dimensional structural heterogeneity and its two-way evolution tuned by structural aging or rejuvenation in a La-based metallic glass. Compared with the resistivity measurements which only signal the most superconductive loop in inhomogeneous materials, the diamagnetic susceptibility signal of the Meissner effect maps the volumetric distribution of all superconductive regions and the corresponding structural heterogeneity in metallic glasses with high sensitivity. The experimental results reported in this article can be well interpreted based on a structural model of tunable "soft liquid-like" regions with soft vibration modes mixed with "hard solid-like" regions, validating the heterogeneity models of metallic glasses with new experimental data and approach. • The Meissner effect can be used to uncover the intrinsic structural heterogeneity in superconductive metallic glasses. • The heterogeneity degree and volumetric distribution of metallic glasses can be estimated by the diamagnetic susceptibility. • The diamagnetic susceptibility is susceptible to structural changes caused by aging or rejuvenation of metallic glasses. [ABSTRACT FROM AUTHOR]

In comparison with photocatalytic process, the catalytic degradation of organic dye pollutants in no need of light irradiation is highly interesting from the energy-saving point of view. In this paper, we developed a new CeGeO 4 catalyst that can satisfy the energy-saving requirements in this regard. During the synthesis of CeGeO 4 , the influence of synthetic medium pH, the kind of precursor, etc., on the formation of crystalline CeGeO 4 was investigated in detail. Importantly, the CeGeO 4 catalyst exhibited significantly higher performance than that of CeGeO 4 /CeO 2 or CeO 2 in degradation of rhodamine B (RhB) or methylene blue (MB) in the dark at room temperature. [ABSTRACT FROM AUTHOR]

Metallic glasses (MGs) have unusual structural characteristics and resulting unique properties, but effectively modulating their structure is difficult. The recently achieved two-way structural tuning (ordering-disordering) between distinct states in MGs offers an opportunity to overcome this challenge. However, pressures up to tens of GPa were required for the process, which limits sample sizes at the micrometer scale and challenges further comprehensive research. Here, by introducing concurrent shear straining with compressive force using high-pressure torsion, the pressure to trigger the disordering transition is significantly reduced to a few GPa. This enables the acquisition of millimeter-sized samples for comprehensive study, including synchrotron x-ray diffraction and small angle x-ray scatting, nanoindentation, electrical resistivity, and differential scanning calorimetry. It is evidenced that the two-way tuning of MG can be achieved both structurally and thermodynamically, which could help deepen our understanding of the mechanism behind the two-way tuning and promote exploration of distinct MGs. [Display omitted] [ABSTRACT FROM AUTHOR]

Atomically dispersed cluster catalysts own versatile applications in biomass valorization, while the controllable assembly and microenvironmental regulation remain a crucial challenge. Herein, Co clusters assembled via nanosized ZIF-67 sprouted from Co-Al layered double hydroxide nanoflowers were applied for selective hydrogenation of furfural (FAL). The pyrolysis temperature can tune the microstructures and acid properties of the catalyst, which accounts for the hydrogenation of FAL to furfuryl alcohol (FOL), 2-methylfuran (2-MF), and tetrahydrofurfuryl alcohol (THFOL) with yield of 99.1 %, 96.7 %, and 82.3 %, respectively. The Co clusters favor C O bond adsorption via bridging-type adsorption mode while suppressing the furan ring adsorption. Moreover, ultra-dispersed Co clusters facilitate the cleavage of C-OH bonds in FOL intermediate, leading to a high 2-MF yield. As the pyrolysis temperature increase, the formed Co nanoparticles are conducive to the parallel adsorption of FAL, resulting in the production of THFOL. This work affords a multi-functional catalyst in catalytic biomass upgrading. [Display omitted] • The ultrafine Co clusters embedded in carbon matrix were developed. • The migration of Co on LDH surface will expose a large number of Lewis acid sites, which facilitate the activation of C=O band. • The microstructure and acid-base properties can be adjusted by varying the pyrolysis conditions. • The relationship between the adsorption mode of substrate and the hydrogenation pathway was thoroughly explored. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrathin borophene nanosheets (<2 nm) were synthesized. • The superior Li-storage capacity of borophene nanosheets is firstly reported. • In-situ XRD depicts the Li-storage mechanism of borophene nanosheet. Two-dimensional borophene nanosheets (2D BNSs) have been theoretically predicted to be an ideal lithium-storage material owing to their high theoretical capacity and low Li-ion diffusion energy barrier. However, the lithium-storage capability and mechanism of 2D BNSs have not yet been reported until now. Herein, ultrathin 2D BNSs (<2 nm) were successfully fabricated by sonication-assisted liquid exfoliation, and further explored as a Li-storage host. The ultrathin BNSs delivered an ultrahigh capacity of 782.9 mAh/g over 500 cycles at 167 mA/g. The Li-storage mechanism of BNSs was revealed by in-situ X-ray diffraction and the results showed that the Li+ ions intercalate/deintercalate along (2 0 5) plane with the formation of interstitial compound of Li 0.48 B. The charge storage behavior of 2D BNSs was also proved to be dominated by a pseudocapacitance-control process, which contributes to the high-rate capability. This work would accelerate the exploration of emerging 2D materials for high-energy–density lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Overlapping stents represent a new paradigm in endovascular interventions, especially for complex and wide-necked aneurysms. The low-profile visualized intraluminal support (LVIS) device is a new generation of self-expanding braided stents recently introduced in China for stent-assisted coiling of intracranial aneurysms. We report several cases of intracranial aneurysms coiled using overlapping LVIS stents to evaluate its efficacy and safety. Patients with ruptured intracranial aneurysms treated with double LVIS stents at our center between November 2014 and May 2016 were reviewed. The clinical data and technical results are presented. Ten patients with 15 aneurysms were treated with double LVIS stents, with a 100% technical success rate. No mortality was observed. Immediate angiographic outcome evaluation showed complete occlusion in 13 aneurysms (86.7%) and neck remnants in 2 aneurysms (13.3%). Double LVIS stents are safe and effective in the treatment of intracranial aneurysms, especially complex aneurysms. [ABSTRACT FROM AUTHOR]

Developing efficient catalysts capable of degrading organic dye free of light irradiation is highly interesting from the energy-saving point of view. In this work, we prepared a new Ce(IO 3 ) 4 catalyst by a facile precipitation method. The obtained Ce(IO 3 ) 4 sample showed remarkably superior performance to the reported CeGeO 4 analog in degradation of rhodamine B (RhB), methyl orange (MO) or methylene blue (MB) dyes in the dark at room temperature. The ultraviolet-visible (UV–vis) absorption spectra of dye solution during degradation, the XPS results of Ce(IO 3 ) 4 and the control experiments confirmed that the dye degradation is a catalytic process. The reusability of it was also investigated in the degradation experiments. [ABSTRACT FROM AUTHOR]

Hexagonal silicon (Si-IV) has recently attracted considerable research interest due to its extraordinary optical properties and possibility to convert into a direct semiconductor under strain with great potential for applications. However, the mechanical properties of Si-IV, which are critical for its applications, have not been experimentally studied yet. In this study, combining nanoindentation and in situ high-pressure synchrotron X-ray diffraction, we thoroughly investigated the mechanical properties of Si-IV. The results suggest that the elastic moduli and hardness of Si-IV are close to those of the common diamond cubic silicon. The similar mechanical properties of Si-IV and diamond cubic silicon are beneficial for integrating Si-IV into conventional Si-based devices using similar industrial processing and for its photovoltaic and optoelectronic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Development of visible-light-responsive photocatalyst is significantly important in treatment of environmental pollution with sustainable solar energy. In this paper, a new visible-light-responsive photocatalyst, HgSe, was successfully prepared by a simple hydrothermal method. The HgSe photocatalyst showed higher photocatalytic activity than that of Degussa P25 (commercial TiO 2 ) in degradation of rhodamine B (RhB) and methyl orange (MO) dyes under irradiation of visible light. The active species of HgSe for the RhB degradation are found to be photogenerated holes and superoxide anion radicals. The HgSe photocatalyst can be reused for at least three cycles without obvious loss of its activity in degradation of RhB. [ABSTRACT FROM AUTHOR]