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Metal-supported zeolite catalysts have been widely used in the NH3 selective catalytic reduction (NH3-SCR) reactions due to their wide temperature window and good hydrothermal stability. In this review, the research progress in the structural characteristics, catalytic performance and reaction mechanism of Cu- and Fe- based zeolite catalysts in NH3-SCR was summarized. In addition, the application of density functional theory (DFT) calculation in clarifying the reaction mechanism of NH3-SCR was introduced. Finally, the reaction kinetics and the apparent kinetic parameters of different metal-based zeolite catalysts in NH3-SCR were compared and discussed. We hope this review could provide new ideas for the study of NH3-SCR reaction mechanism over metal-supported zeolite catalysts.

Singapore’s first multi-source high-flux solar simulator (HFSS) that comprises an array of seven 4-kWe xenon short-arc lamps close-coupled with ellipsoidal reflectors is designed, constructed, and characterized. An indirect mapping system that consists of a water-cooled Lambertian target, a CMOS camera, and a heat-flux gauge is adopted herein to experimentally characterize the performance of the developed HFSS. A calibration constant of 192.8 ± 9.6 kW m−2 (GS µs−1)–1 is determined and used to transform the raw-flux maps with grayscale values to the absolute-flux maps. Utilizing a series of flexible and precise adjusters, the variability of ± 1 mm in the x- and y-directions of the peak flux points of the radiation modules is measured. A peak flux of 7740 kW m−2 is measured for the sum of all 7 radiation modules. Average radiative fluxes of 4191 kW m−2 and 2933 kW m−2 can be observed from circular target areas of O40 mm and O60 mm, respectively, associated with promising electricity-to-target transfer efficiencies of 18.8% and 29.6%. A Monte Carlo ray-tracing (MCRT) model is calibrated by the experimental data. Based on the minimum root-mean-standard deviation between the measured and simulated results of the radiative power on the target, the optimal parameters of the MCRT model include the arc radius of 3.4 mm and the reflector surface error of 1.1 mrad.

Emission of NOx from stationary and mobile sources had caused many environmental problems. NH3 selective catalytic reduction technology (NH3-SCR) is one of the most effective technologies to eliminate NOx based on developing high-efficient catalysts. In this review, the catalytic activity for NH3-SCR, hydrothermal stability and deactivation mechanism of metal-based zeolite catalysts (mainly Cu− and Fe-based zeolite catalysts) employed in NH3-SCR were summarized. The main factors affecting the hydrothermal stability of Cu- or Fe-based zeolite catalysts in NH3-SCR, such as Si/Al ratio, zeolite topological structure, metal content, particle size and preparation methods of catalysts, were systematically reviewed. The modification approaches addressed in recent researches which could effectively improve the hydrothermal stability of metal-based zeolites in NH3-SCR, such as element modification using phosphorus, second active metal, alkali (earth) metal, and surface modification, were discussed. Hopefully, this review could provide a fundamental understanding of the deactivation behaviors of Cu- and Fe-based zeolite catalysts and pave the way towards the improvement of hydrothermal stability of zeolite catalysts in NH3-SCR.

Background Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a novel inflammatory biomarker, which is useful as an adjunct identification tool for cardiovascular disease. However, the important limitation of the conventional enzyme-linked immunosorbent assay (PLAC ELISA) for Lp-PLA2 assay is its relatively low sensitivity and time consuming. A method to measure the Lp-PLA2 simply, rapidly and sensitively is essential for predicting cardiovascular events in clinic. Methods We took advantage of magnetic separation integrated with chemiluminescence to detect Lp-PLA2. The concentration of Lp-PLA2 was measured through a one-step process by mixing antibody labelled magnetic beads, antigen and antibody at one time. Results Our method realized the sample to answer within 17 min. The detection limit and measurement range were 0.18 ng/ml and 0.18–1350 ng/ml, respectively. The specificity assay showed that no appreciable interference was observed for the substances of bilirubin, triglyceride, hemoglobin, rheumatoid factor and human anti-mouse antibody up to the concentrations of 40 mg/dl, 1000 mg/dl, 2000 mg/dl, 1500 IU/ml and 30 ng/ml, separately. We also tested 122 clinical samples using our method, presenting good overall correlations (R2 = 0.979) to the PLAC ELISA. It is worth mentioning that, our method was faster, had a wider range of measurement and higher sensitivity compared with the PLAC ELISA. Conclusions The Lp-PLA2 assay is straightforward, sensitive and precise, which is highly suitable to further explore the clinical performance of Lp-PLA2 in studies of cardiovascular risk management.

Salvia miltiorrhiza is a traditional medicinal plant mainly used for cardiovascular and cerebrovascular disease treatment. Tanshinones are the main bioactive constituents of S. miltiorrhiza, which mainly accumulate around its root periderm tissue. Endophytic fungi are important bioelicitors or probiotics that can promote the accumulation of secondary metabolites and sustainable cultivation of medicinal plants. Among them, endophytic Cladosporium spp., possessing a variety of biotransformation and metabolic abilities, is an ideal elicitor source. Here, we used a gnotobiotic system to investigate the effects of the endophytic fungus Cladosporium tenuissimum DF11 on tanshinone biosynthesis in S. miltiorrhiza roots. The results showed that C. tenuissimum DF11 mainly colonizes the intercellular space of the root tissues and promotes tanshinone biosynthesis and accumulation in S. miltiorrhiza roots by upregulating the expression of the genes encoding for key enzymes HMGR, DXS, DXR, GGPPS, CPS, KSL and CYP76AH1 of the tanshinone biosynthesis pathway. The expression levels of almost all genes encoding for key enzymes reached the response peak in the first or second week after DF11 colonization. Taken together, the endophytic fungus C. tenuissimum DF11 could promote secondary metabolite accumulation in S. miltiorrhiza roots. These results indicate that DF11 will be a potential biofertilizer fungus to regulate and stabilize the quality of cultivated S. miltiorrhiza medicinal materials.

Orf virus (ORFV) is a parapoxvirus causing contagious ecthyma in sheep and goats. With inhibitory role of ORFV reported by previous studies, ORFV can be a candidate of oncolytic virus. However, few studies reported the application and mechanism of ORFV in nasopharyngeal carcinoma (NPC). We aimed to elucidate the anti-tumor mechanism of ORFV against NPC cells.The anti-tumor effect of ORFV in NPC cells was confirmed by cell counting kit 8 (CCK-8) assay, flow cytometry and Western blot. In vitro and in vivo experiments were adopted to evaluate the inhibitory effect of ORFV in NPC cells. Western blot was used to determine the down-regulation of rapamycin (mTOR) signaling and autophagy enhancement induced by ORFV. To explore the mechanism of ORFV on NPC cells, mTOR signaling agonist and autophagy inhibitors were used to rescue the effects of ORFV.The results indicated that ORFV replicates in NPC cells, thus induces the apoptosis of NPC cells. Moreover, ORFV can effectively inhibit NPC cell growth in vivo. ORFV infection in NPC cells leads to the mTOR signaling inhibition and up-regulated autophagy, which might be the specific mechanism of ORFV in killing tumor cells. As to safety confirmation, normal nasopharyngeal epithelial cells NP69 are insensitive to ORFV. More importantly, ORFV would not cause organ damage in vivo.Our data clarified that ORFV induces autophagy of NPC cells via inhibiting mTOR signaling, thus further inducing apoptosis. The anti-tumor role of ORFV might provide a preclinical strategy for NPC treatment.

Fluidized-bed based solar reactors for the gasification of biomass have been widely recognized as a promising approach to produce high-quality syngas due to the merits, e.g. continuous operation and superior heat and mass transport. In this work, a novel high-temperature solar reactor with a clapboard-type internally circulating configuration that can efficiently mitigate the overheating of the bed wall affected by non-uniform solar radiation, is designed, constructed, and experimentally investigated under Singapore’s first 28 kWe high-flux solar simulator. To investigate the flow dynamics in the high-temperature solar reactor, a transient 3D computational fluid dynamics multi-phase model is developed accordingly and validated by the experimental data. The simulated results can well clarify the flow and thermal behaviours in experiments. The effects of the gas flow rate and bed mass on the thermal performances of different Group-B particle materials are studied through experiments and simulation. The results indicate that increasing the bed mass in the solar reactor is capable of mitigating the overheating of the absorber surface caused by hot spots. The gas flow rate is dependent on the particle thermo-physical properties and shape as well as the clapboard geometric parameters. The highest solar-to-thermal conversion efficiency (defined as the ratio of the accumulated sensible heat of the particles to the solar power input) of 10.7 ± 0.4% is achieved by SiC due to its superior thermal conductivity.

Cefprozil, a semi-synthetic antibiotic, has been used in pediatric therapy. The purpose of this study was to improve the yield of cefprozil and obtain purer product in an aqueous two-phase system composed of P ADB and P MDB . P ADB and P MDB were synthesized using acrylic acid, methacrylic acid, 2-dimethylaminoethyl methacrylate, and butyl methacrylate. Cefprozil was synthesized with 7-amino-3-(1-propenyl)-4-cephalosporanic acid (7-APRA) as the main ring, ( R )-amino-(4-hydroxyphenyl) acetic acid methyl ester hydrochloride (D-HPGME-HCl) as the acyl donor and the immobilized penicillin acylase as the catalyst. 7-APRA and D-HPGME-HCl were concentrated in the P MDB -rich phase, while cefprozil was in the P ADB -rich phase. The optimal partitiona coefficient of cefprozil was 1.84 with 40 mM KSCN, while the enzyme reaction yield of cefprozil reached 99.39% compared with 77.61% in the aqueous-phase system. The recovery of the two copolymers was up to 96.01% at pH 3.54. After crystallization, the purity of the product reached 88.02%, and no copolymer remained in the product. The combination of cefprozil∙DMF was detected by gas chromatography-mass spectrometry, FT-IR spectroscopy, thermogravimetric analysis, and electrospray ionization mass spectrometry. The results showed that no chemical bond existed between cefprozil and DMF.

A 7-kWth indirectly irradiated solar gasifier with a clapboard-type internally circulating fluidized bed was developed and conducted experimentations under concentrated solar radiation. The solar CO2 gasification of charcoal produced by low-temperature pyrolysis was examined under a 28-kWe high-flux solar simulator considering different operating conditions. The effects of CO2:C and feedstock mass on the key performance indicators e.g. the carbon conversion, energetic upgrade factor, and solar conversion efficiency were investigated by using alumina granules as an inert bed material. The first-hand, reproducible experimental data indicated the highest values of the average carbon conversion of 0.53 ± 0.04, energetic upgrade factor of 0.883 ± 0.03, solar conversion efficiency of 5.3 ± 0.6% were achieved under the operating conditions of 80 g charcoal, 1.5 kg alumina particles, and 2 L/min CO2. The feedstock mass significantly affected the solar conversion efficiency but no notable effect on the energetic upgrade factor was observed. The solar conversion efficiency can be significantly improved via fully replacing inert alumina particles by feedstock, adding a continuous feeder, and optimizing the superficial velocity to minimize particle entrainment.

Biomass gasification-based cogeneration systems integrated with dehumidification of desiccant coated heat exchangers, covering the cogeneration system inclusive of sensible heat storage and internal heat recovery (SC-1), the cogeneration system inclusive of sensible heat storage (SC-2), and the cogeneration system exclusive of heat storage and internal heat recovery (SC-3), are introduced and comparatively investigated on the energetic and economic performances. The developed models of the cogeneration systems are embedded into a multi-criteria decision-making framework to find the optimal system configuration and parameters. The most favorable scheme (SC-1) – that reaches an overall energy efficiency of 0.963, net present value of 1,429,400 USD, levelized total cost of 646,835 USD/year, payback period of 3.7, heat storage tank of 7 m3, heat recovery tank of 2.1 m3, jacket heat rate of 290 kW, and nominal electric power of 629 kWe – is determined. The sensitivity analysis indicates that the net present value is most sensitive to the electricity tariffs, followed by the biomass feedstock price and the selling price of electricity to utility grid. The overall energy efficiency of 0.81–0.995, the net present value of −470,400–6,166,900 USD, and the payback period of 1.5–13.1 were achieved against the price variation range of ±80%.

Despite the advantage of power efficiency and spectral efficiency, spatial modulation (SM) technology makes communication systems sensitive to the transmission impairment. This paper analytically investigates the performance of SM multiple-input multiple-output (MIMO) systems where power amplifier (PA) shows clear nonlinearity. Firstly, the system model is presented with nonlinear distortion included. Secondly, the system symbol error rate (SER) is newly derived to a polynomial based function of system parameters. Thirdly, the asymptotical behaviour of SER is analysed, and it is found that SER in nonlinear SM-MIMO systems has a lower limit. Finally, the analytical expressions of SER lower bond are presented. The analysis methodology and derived findings can be a useful reference for the designers of SM-MIMO systems.

Nowadays, waste-to-energy systems have attracted more and more attentions. Gasification technology is one of the most important methods of waste-to-energy utilization. For further using the residual heat of the gasification system, a desiccant dehumidification unit with heat recovery using desiccant coated heat exchanger (DCHE) driven by waste heat is developed. Two DCHEs are employed to remove moisture from fresh air. The hot water used in the regeneration process comes from the gasification combined heat and power (CHP) subsystem. Under the typical outdoor condition in Singapore (32 °C, 65% RH), the moisture removal of the system reaches 9.32 g/kgDA, the thermal COP is 0.70, and the waste heat utilization ratio approaches 74.2%. To improve the energy efficiency further, a heat recovery subsystem is adopted to recover the waste heat from the exhausted regeneration air. The recommended pre-regeneration time is 3 min, and the moisture removal is 9.01 g/kg DA, while the thermal COP and waste heat utilization ratio are remarkably increased to 1.34% and 86.5%, respectively. Detailed parametric analyses were carried out, including the influences of the cooling water flow rate, hot water flow rate and hot water temperature. This system combines desiccant coated heat exchangers and the gasification CHP subsystem innovatively to improve the energy utilization of waste-to-energy gasification system, which turns out an effective choice to achieve dehumidification and recover waste heat deeply.

Due to the tar contamination caused by the gasification process of biomass, the internal combustion engine (ICE) based gasification cogeneration systems require complicated gas cleaning devices to purify producer gas. In this paper, a Stirling engine based gasification combined cooling, heat and power (CCHP) system was introduced, which has the capability of mitigating tar condensation and contamination. The gasification CCHP system, including the gasification system, the Stirling engine system, and the absorption chiller system, can provide electricity, heat and cooling for a commercial building. The effects of the equivalence ratio on syngas composition and cold gas efficiency of the gasification process were analyzed herein. The optimal systems in Singapore and Shanghai can save respectively 75.9% and 70.5% levelized total cost compared to a conventional reference system. The Stirling engine based CCHP system had advantages over the ICE systems on overall consideration of the levelized total cost and the primary energy saving ratio. The monthly energetic, economic and environmental performance of the CCHP systems was evaluated under different modes and the above two systems’ primary energy saving ratios, operation cost reduction ratios and CO2 equivalent reduction ratios respectively reached 0.886, 0.462 and 0.701 in Singapore and 0.908, 0.535 and 0.710 in Shanghai in annual operation. The outcomes of this paper contribute to the design and deployment of such a CCHP system, and the developed models and analysis framework can be extended to different climate areas.

It was found that the output power of the distributed feedback fiber lasers would be improved after annealing or left unused for several days after the laser had been fabricated, and the output of the fundamental mode would not increase but be clamped while the ±1 order modes would be predominant with the enhancement of the coupling coefficient during the fabrication. The paper discussed the influence of UV-induced fiber loss on the fiber phase-shifted DFB lasers. Due to the gain saturation and fiber internal loss, which included the temperament loss and permanent loss, there was an optimum coupling coefficient for the DFB fiber lasers that the higher internal fiber loss corresponded to the lower optimum values of coupling coefficient.