Confinement-Induced Indium Oxide Nanolayers Formed on Oxide Support for Enhanced CO2 Hydrogenation Reaction.

An enclosed nanospace often shows a significant confinement effect on chemistry within its inner cavity, while whether an open space can have this effect remains elusive. Here, we show that the open surface of TiO2 creates a confined environment for In2O3 which drives spontaneous transformation of free In2O3 nanoparticles in physical contact with TiO2 nanoparticles into In oxide (InOx) nanolayers covering onto the TiO2 surface during CO2 hydrogenation to CO. The formed InOx nanolayers are easy to create surface oxygen vacancies but are against over-reduction to metallic In in the H2-rich atmospheres, which thus show significantly enhanced activity and stability in comparison with the pure In2O3 catalyst. The formation of interfacial In-O-Ti bonding is identified to drive the In2O3 dispersion and stabilize the metastable InOx layers. The InOx overlayers with distinct chemistry from their free counterpart can be confined on various oxide surfaces, demonstrating the important confinement effect at oxide/oxide interfaces.

What Elements Really Intercalate into Pd Lattice When Heated in Dimethylformamide?

Palladium hydrides (PdHx) are pivotal in both fundamental research and practical applications across a wide spectrum. PdHx nanocrystals, synthesized by heating in dimethylformamide (DMF), exhibit remarkable stability, granting them widespread applications in the field of electrocatalysis. However, this stability appears inconsistent with their metastable nature. The substantial challenges in characterizing nanoscale structures contribute to the limited understanding of this anomalous phenomenon. Here, through a series of well-conceived experimental designs and advanced characterization techniques, including aberration-corrected scanning transmission electron microscopy (AC-STEM), in situ X-ray diffraction (XRD), and time-of-flight secondary ion mass spectrometry (TOF-SIMS), we have uncovered evidence that indicates the presence of C and N within the lattice of Pd (PdCxNy), rather than H (PdHx). By combining theoretical calculations, we have thoroughly studied the potential configurations and thermodynamic stability of PdCxNy, demonstrating a 2.5:1 ratio of C to N infiltration into the Pd lattice. Furthermore, we successfully modulated the electronic structure of Pd nanocrystals through C and N doping, enhancing their catalytic activity in methanol oxidation reactions. This breakthrough provides a new perspective on the structure and composition of Pd-based nanocrystals infused with light elements, paving the way for the development of advanced catalytic materials in the future.

Improving the Hydrogen Oxidation Reaction Rate of Ru by Active Hydrogen in the Ultrathin Pd Interlayer.

Enhancing the catalytic activity of Ru metal in the hydrogen oxidation reaction (HOR) potential range, improving the insufficient activity of Ru caused by its oxophilicity, is of great significance for reducing the cost of anion exchange membrane fuel cells (AEMFCs). Here, we use Ru grown on Au@Pd as a model system to understand the underlying mechanism for activity improvement by combining direct in situ surface-enhanced Raman spectroscopy (SERS) evidence of the catalytic reaction intermediate (OHad) with in situ X-ray diffraction (XRD), electrochemical characterization, as well as DFT calculations. The results showed that the Au@Pd@Ru nanocatalyst utilizes the hydrogen storage capacity of the Pd interlayer to "temporarily" store the activated hydrogen enriched at the interface, which spontaneously overflows at the "hydrogen-deficient interface" to react with OHad adsorbed on Ru. It is the essential reason for the enhanced catalytic activity of Ru at anodic potential. This work deepens our understanding of the HOR mechanism and provides new ideas for the rational design of advanced electrocatalysts.

Long-wave-infrared pulse production at 11 µm via difference-frequency generation driven by femtosecond mid-infrared all-fluoride fiber laser.

We present an ultrafast long-wave infrared (LWIR) source driven by a mid-infrared fluoride fiber laser. It is based on a mode-locked Er:ZBLAN fiber oscillator and a nonlinear amplifier operating at 48 MHz. The amplified soliton pulses at ∼2.9 µm are shifted to ∼4 µm via the soliton self-frequency shifting process in an InF3 fiber. LWIR pulses with an average power of 1.25-mW centered at 11 µm with a spectral bandwidth of ∼1.3 µm are produced through difference-frequency generation (DFG) of the amplified soliton and its frequency-shifted replica in a ZnGeP2 crystal. Soliton-effect fluoride fiber sources operating in the mid-infrared for driving DFG conversion to LWIR enable higher pulse energies than with near-infrared sources, while maintaining relative simplicity and compactness, relevant for spectroscopy and other applications in LWIR.

Mid-IR pulse amplification to ∼millijoule energies in a single transverse mode using large core Er:ZBLAN fibers operating at 2.8µm.

We demonstrate single transverse mode and high energy nanosecond pulse amplification at ∼2.8-µm using large core Er:ZBLAN fibers. The highest energies achieved are 0.75mJ from a 50 µm core, and 420µJ from a 30 µm core fibers respectively, seeded with 95 ns long pulses generated by a ring-cavity Q-switched Er:ZBLAN fiber laser. Nearly diffraction-limited beams with M2 = 1.2-1.3 were obtained using a single-mode excitation technique of multi-mode core fibers. Achieved pulse energies exceed by approximately an order of magnitude the previously reported highest pulse energies in a single transverse mode from a fiber laser or amplifier at these mid-IR wavelengths.

Structure and Properties of Ultrathin SiOx Films on Cu(111).

The metal-oxide interface plays a crucial role in catalysis, and it has attracted increasing interest in recent years. Cu/SiO2, as a common copper-based catalyst, has been widely used in industrial catalysis. However, it is still a challenge to clarify the structures of the interface of Cu-SiOx and the effect on catalytic performance. Herein, we prepared ultrathin SiOx films by evaporating Si onto a Cu(111) surface followed by annealing in an O2 atmosphere, which were characterized by various surface science techniques. The results showed that a SiOx film could grow nearly layer-by-layer on the Cu(111) surface in the present condition. Both X-ray photoelectron spectroscopy (XPS) and high-resolution electron energy loss spectroscopy (HREELS) results confirmed the presence of Cu-O-Si and Si-O-Si species. Thermal stability experiments illustrated that the well-ordered silica films were stable under annealing in vacuum. The feature of CO adsorption suggested a CO-Cuδ+ species induced from the Cuδ+-O-Si. Low-energy ion scattering spectroscopy (LEIS) and XPS results demonstrated that some Cu2O appeared on the surface when the 1 ML SiOx/Cu(111) was exposed in O2 at 353 K.

Evaluating the comparative efficiency of medical centers in Taiwan: a dynamic data envelopment analysis application.

BACKGROUND: People in Taiwan enjoy comprehensive National Health Insurance coverage. However, under the global budget constraint, hospitals encounter enormous challenges. This study was designed to examine Taiwan medical centers' efficiency and factors that influence it. METHODS: We obtained data from open sources of government routine publications and hospitals disclosed by law to the National Health Insurance Administration, Ministry of Health and Welfare, Taiwan. The dynamic data envelopment analysis (DDEA) model was adopted to estimate all medical centers' efficiencies during 2015-2018. Beta regression models were used to model the efficiency level obtained from the DDEA model. We applied an input-oriented approach under both the constant returns-to-scale (CRS) and variable returns-to-scale (VRS) assumptions to estimate efficiency. RESULTS: The findings indicated that 68.4% (13 of 19) of medical centers were inefficient according to scale efficiency. The mean efficiency scores of all medical centers during 2015-2018 under the CRS, VRS, and Scale were 0.85, 0.930, and 0.95,respectively. Regression results showed that an increase in the population less than 14 years of age, assets, nurse-patient ratio and bed occupancy rate could increase medical centers' efficiency. The rate of emergency return within 3-day and patient self-pay revenues were associated significantly with reduced hospital efficiency (p < 0.05). The result also showed that the foundation owns medical center has the highest efficiency than other ownership hospitals. CONCLUSIONS: The study results provide information for hospital managers to consider ways they could adjust available resources to achieve high efficiency.

Detachable Liposomes Combined Immunochemotherapy for Enhanced Triple-Negative Breast Cancer Treatment through Reprogramming of Tumor-Associated Macrophages.

Triple-negative breast cancer (TNBC) is an aggressive disease with a high recurrence rate and poor outcomes in clinic. In this study, inspired by the enriched innate immune cell type tumor-associated macrophages (TAMs) in TNBC, we proposed a matrix metalloprotease 2 (MMP2) responsive integrated immunochemotherapeutic strategy to deliver paclitaxel (PTX) and anti-CD47 (aCD47) by detachable immune liposomes (ILips). In the TNBC microenvironment, the "two-in-one" ILips facilitated MMP2-responsive release of aCD47 to efficiently polarize M2 macrophages toward the M1 phenotype to enhance phagocytosis against tumor cells and activate the systemic T cell immune response. Together with the immune effect, the detached PTX-loaded liposomes were internalized in MDA-MB-231 cells to synergistically inhibit tumor cell proliferation and metastasis. In the TNBC-bearing mouse model, PTX-loaded ILips demonstrated superior antitumor efficacy against TNBC and inhibited tumor recurrence. Our integrated strategy represents a promising approach to synchronously enhance immune response and tumor-killing effects, improving the therapeutic efficacy against TNBC.

Smart-Polypeptide-Coated Mesoporous Fe3O4 Nanoparticles: Non-Interventional Target-Embolization/Thermal Ablation and Multimodal Imaging Combination Theranostics for Solid Tumors.

Tumor theranostics hold great potential for personalized medicine in the future, and transcatheter arterial embolization (TAE) is an important clinical treatment for unresectable or hypervascular tumors. In order to break the limitation, simplify the procedure of TAE, and achieve ideal combinatorial theranostic capability, here, a kind of triblock-polypeptide-coated perfluoropentane-loaded mesoporous Fe3O4 nanocomposites (PFP-m-Fe3O4@PGTTCs) were prepared for non-interventional target-embolization, magnetic hyperthermia, and multimodal imaging combination theranostics of solid tumors. The results of systematic animal experiments by H22-tumor-bearing mice and VX2-tumor-bearing rabbits in vivo indicated that PFP-m-Fe3O4@PGTTC-6.3 has specific tumor accumulation and embolization effects. The tumors' growth has been inhibited and the tumors disappeared 4 weeks and ≤15 days post-injection with embolization and magnetic hyperthermia combination therapy, respectively. The results also showed an excellent effect of magnetic resonance/ultrasound/SPECT multimodal imaging. This pH-responsive non-interventional embolization combinatorial theranostics system provides a novel embolization and multifunctional theranostic candidate for solid tumors.

Chitosan oligosaccharide modified liposomes enhance lung cancer delivery of paclitaxel.

Lung cancer is one of the leading causes of cancer-related death worldwide. Various therapeutic failed in the effective treatment of the lung cancer due to their limited accumulation and exposure in tumors. In order to promote the chemotherapeutics delivery to lung tumor, we introduced chitosan oligosaccharide (CSO) modification on the liposomes. CSO conjugated Pluronic P123 polymers with different CSO grafting amounts, called as CP50 and CP20, were synthesized and used to prepare CSO modified liposomes (CP50-LSs and CP20-LSs). CP50-LSs and CP20-LSs displayed significantly enhanced cellular uptake in A549 cells in vitro as well as superior tumor accumulation in vivo compared with non-CSO modified liposomes (P-LSs). This phenomenon was related to the increased affinity between CSO modified liposomes and tumor cells following massive adsorption of collagen, which was highly expressed in lung tumors. In the A549 tumor-bearing mouse model, intravenous injection of paclitaxel (PTX)-loaded CP50-LSs every 3 days for 21 days resulted in optimal antitumor therapeutic performance with an inhibition rate of 86.4%. These results reveal that CSO modification provides promising applicability for nanomedicine design in the lung cancer treatment.

Data analysis of ambient intelligence in a healthcare simulation system: a pilot study in high-end health screening process improvement.

BACKGROUND: This study aimed to reduce the total waiting time for high-end health screening processes. METHOD: The subjects of this study were recruited from a health screening center in a tertiary hospital in northern Taiwan from September 2016 to February 2017, where a total of 2342 high-end customers participated. Three policies were adopted for the simulation. RESULTS: The first policy presented a predetermined proportion of customer types, in which the total waiting time was increased from 72.29 to 83.04 mins. The second policy was based on increased bottleneck resources, which provided significant improvement, decreasing the total waiting time from 72.29 to 28.39 mins. However, this policy also dramatically increased the cost while lowering the utilization of this health screening center. The third policy was adjusting customer arrival times, which significantly reduced the waiting time-with the total waiting time reduced from 72.29 to 55.02 mins. Although the waiting time of this policy was slightly longer than that of the second policy, the additional cost was much lower. CONCLUSIONS: Scheduled arrival intervals could help reduce customer waiting time in the health screening department based on the "first in, first out" rule. The simulation model of this study could be utilized, and the parameters could be modified to comply with different health screening centers to improve processes and service quality.

On-Surface Decarboxylation Coupling Facilitated by Lock-to-Unlock Variation of Molecules upon the Reaction.

On-surface synthesis (OSS) involving relatively high energy barriers remains challenging due to a typical dilemma: firm molecular anchor is required to prevent molecular desorption upon the reaction, whereas sufficient lateral mobility is crucial for subsequent coupling and assembly. By locking the molecular precursors on the substrate then unlocking them during the reaction, we present a strategy to address this challenge. High-yield synthesis based on well-defined decarboxylation, intermediate transition, and hexamerization is demonstrated, resulting in an extended and ordered network exclusively composed of the newly synthesized macrocyclic compound. Thanks to the steric hindrance of its maleimide group, we attain a preferential selection of the coupling. This work unlocks a promising path to enrich the reaction types and improve the coupling selectivity hence the structual homogeneity of the final product for OSS.

Persistence and Oscillations of Plant-Pollinator-Herbivore Systems.

This paper considers plant-pollinator-herbivore systems where the plant produces food for the pollinator, the pollinator provides pollination service for the plant in return, while the herbivore consumes both the food and the plant itself without providing pollination service. Based on these resource-consumer interactions, we form a plant-pollinator-herbivore model which includes the intermediary food. Using qualitative method and Kuznetsov theorem, we show global dynamics of the subsystems, uniform persistence of the whole system and periodic oscillation by Hopf bifurcation. Rigorous analysis on the system demonstrates mechanisms by which varying parameters could make the system transition between extinction of herbivore, coexistence of the three species at steady states, coexistence in periodic oscillations and extinction of pollinator. It is shown that (i) in plant-pollinator interactions, the plant would produce food; (ii) in plant-herbivore interactions, the plant would produce toxin; (iii) in the presence of both pollinator and herbivore, the plant would produce both food and toxin, and intermediate productions are analytically given by which the plant can reach its maximal density; and (iv) an appropriate toxin production could drive the herbivore into extinction, an unappropriate one would drive the pollinator into extinction, while too much toxin production will drive the plant itself into extinction. The analysis leads to explanations for experimental observations and provides new insights.

Surface Compositions of Oxide Supported Bimetallic Catalysts: A Compared Study by High-Sensitivity Low Energy Ion Scattering Spectroscopy and X-Ray Photoemission Spectroscopy.

It is well known that there is a critical relationship between the surface composition and catalytic performance for a bimetallic catalyst. However, in most cases, the surface composition is obviously different from that of the bulk. Moreover, the surface is normally reconstructed under reaction conditions. In this personal account, our recent progresses in determining the surface compositions of oxide supported bimetal catalysts by high-sensitivity low energy ion scattering spectroscopy (HS-LEIS) and X-ray photoemission spectroscopy (XPS) are summarized. Phase diagrams of the surface compositions under various conditions as a function of the bulk composition are established and compared. It is found that oxidation induces de-alloying and enrichment of PdO, CuO, SnO2 on the surface, while H2 reduction results in re-alloying. The addition of the second component not only modifies the nature of the active site, but also varies the dispersion of the active components. The support effects are discussed. The compared studies reveal that HS-LEIS can achieve a more reliable surface composition for oxide supported catalysts.

Direct Conversion of Syngas into Methyl Acetate, Ethanol, and Ethylene by Relay Catalysis via the Intermediate Dimethyl Ether.

Selective conversion of syngas (CO/H2 ) into C2+ oxygenates is a highly attractive but challenging target. Herein, we report the direct conversion of syngas into methyl acetate (MA) by relay catalysis. MA can be formed at a lower temperature (ca. 473 K) using Cu-Zn-Al oxide/H-ZSM-5 and zeolite mordenite (H-MOR) catalysts separated by quartz wool (denoted as Cu-Zn-Al/H-ZSM-5|H-MOR) and also at higher temperatures (603-643 K) without significant deactivation using spinel-structured ZnAl2 O4 |H-MOR. The selectivity of MA and acetic acid (AA) reaches 87 % at a CO conversion of 11 % at 643 K. Dimethyl ether (DME) is the key intermediate and the carbonylation of DME results in MA with high selectivity. We found that the relay catalysis using ZnAl2 O4 |H-MOR|ZnAl2 O4 gives ethanol as the major product, while ethylene is formed with a layer-by-layer ZnAl2 O4 |H-MOR|ZnAl2 O4 |H-MOR combination. Close proximity between ZnAl2 O4 and H-MOR increases ethylene selectivity to 65 %.

New Insights into the Role of Al2 O3 in the Promotion of CuZnAl Catalysts: A Model Study.

The Cu/Al2 O3 /ZnO(0001)-Zn ternary model catalysts and their binary analogues were prepared and characterized. It was found that Al2 O3 grew on the ZnO(0001)-Zn surface by a layer-by-layer model, whereas Cu grew on the ZnO(0001)-Zn surface as two-dimensional clusters up to 0.2 monolayers (ML), and thereafter formed three-dimensional clusters. Because of the layer-by-layer growth of Al2 O3 on the ZnO(0001)-Zn, Cu/Al2 O3 can be considered without the effect of ZnO. Ternary model catalyst Cu/Al2 O3 /ZnO(0001)-Zn, which has all three parts on the surface, was prepared by deposition of Cu on the surface of Al2 O3 /ZnO(0001)-Zn. Low-energy ion scattering spectra showed that Cu preferred to locate at the Al2 O3 /ZnO interfaces. Compared with Cu/ZnO, the addition of Al2 O3 obviously suppressed the reduction of copper oxides and led to a higher concentration of Cu+ . The Cu clusters were found to be covered by thin ZnOx overlayers after reduction of Cu/Al2 O3 /ZnO(0001)-Zn by using H2 . Therefore, the high activity of industrial Cu/ZnO/Al2 O3 catalysts may origin from Cu+ -rich clusters at the Al2 O3 /ZnO interface that are covered by thin ZnOx overlayers.

Graphene cover-promoted metal-catalyzed reactions.

Graphitic overlayers on metals have commonly been considered as inhibitors for surface reactions due to their chemical inertness and physical blockage of surface active sites. In this work, however, we find that surface reactions, for instance, CO adsorption/desorption and CO oxidation, can take place on Pt(111) surface covered by monolayer graphene sheets. Surface science measurements combined with density functional calculations show that the graphene overlayer weakens the strong interaction between CO and Pt and, consequently, facilitates the CO oxidation with lower apparent activation energy. These results suggest that interfaces between graphitic overlayers and metal surfaces act as 2D confined nanoreactors, in which catalytic reactions are promoted. The finding contrasts with the conventional knowledge that graphitic carbon poisons a catalyst surface but opens up an avenue to enhance catalytic performance through coating of metal catalysts with controlled graphitic covers.

The Formation of Surface Lithium-Iron Ternary Hydride and its Function on Catalytic Ammonia Synthesis at Low Temperatures.

Lithium hydride (LiH) has a strong effect on iron leading to an approximately 3 orders of magnitude increase in catalytic ammonia synthesis. The existence of lithium-iron ternary hydride species at the surface/interface of the catalyst were identified and characterized for the first time by gas-phase optical spectroscopy coupled with mass spectrometry and quantum chemical calculations. The ternary hydride species may serve as centers that readily activate and hydrogenate dinitrogen, forming Fe-(NH2 )-Li and LiNH2 moieties-possibly through a redox reaction of dinitrogen and hydridic hydrogen (LiH) that is mediated by iron-showing distinct differences from ammonia formation mediated by conventional iron or ruthenium-based catalysts. Hydrogen-associated activation and conversion of dinitrogen are discussed.

GVD-insensitive stable radio frequency phase dissemination for arbitrary-access loop link.

We propose and experimentally demonstrate a stable radio frequency (RF) phase dissemination scheme for a long-haul optical fiber loop link based on frequency mixing. Using a single optical source in both directions of the loop link, additional timing jitter caused by group velocity dispersion (GVD) can be eliminated. Impressive scalability provided by the optical link ensures that arbitrary-access node can obtain an RF signal with a stabilized phase to meet the requirements of multiple users. In our experiment, a 2.4 GHz RF signal is distributed to arbitrary points along a 100 km fiber-optic loop link steadily. Stabilities of the recovered signals from two accessing nodes are recorded. The root-mean-square (RMS) phase jitter of the received signal at either accessing node is reduced from 1.87 rad to no more than 0.027 rad during 1800-second measuring time.

Improvement of the quality of work in a biochemistry laboratory via measurement system analysis.

An adequate and continuous monitoring of operational variations can effectively reduce the uncertainty and enhance the quality of laboratory reports. This study applied the evaluation rule of the measurement system analysis (MSA) method to estimate the quality of work conducted in a biochemistry laboratory. Using the gauge repeatability & reproducibility (GR&R) approach, variations in quality control (QC) data among medical technicians in conducting measurements of five biochemical items, namely, serum glucose (GLU), aspartate aminotransferase (AST), uric acid (UA), sodium (Na) and chloride (Cl), were evaluated. The measurements of the five biochemical items showed different levels of variance among the different technicians, with the variances in GLU measurements being higher than those for the other four items. The ratios of precision-to-tolerance (P/T) for Na, Cl and GLU were all above 0.5, implying inadequate gauge capability. The product variation contribution of Na was large (75.45% and 31.24% in normal and abnormal QC levels, respectively), which showed that the impact of insufficient usage of reagents could not be excluded. With regard to reproducibility, high contributions (of more than 30%) of variation for the selected items were found. These high operator variation levels implied that the possibility of inadequate gauge capacity could not be excluded. The analysis of variance (ANOVA) of GR&R showed that the operator variations in GLU measurements were significant (F=5.296, P=0.001 in the normal level and F=3.399, P=0.015 in the abnormal level, respectively). In addition to operator variations, product variations of Na were also significant for both QC levels. The heterogeneity of variance for the five technicians showed significant differences for the Na and Cl measurements in the normal QC level. The accuracy of QC for five technicians was identified for further operational improvement. This study revealed that MSA can be used to evaluate product and personnel errors and to improve the quality of work in a biochemical laboratory through proper corrective actions.