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Microfluidic chips with the function of hydrodynamic focusing is widely used in the field of cell electroporation, droplet formation, drug screening and particle enrichment. Due to the small channel size of microfluidic chip, the existing processing methods have the defects of high fabrication cost or low dimensional consistency, the drawback is particularly prominent at small fabrication quantity. In this study, hydrodynamic focusing microfluidic chip was successfully fabricated by Liquid Crystal Display (LCD) mask photo-curing method with high efficiency and precision, the mechanism of curing parameters on the accuracy of microstructure was investigated, the hot pressing process was proposed to realize the bonding of cured photosensitive resin and glass substrate. By analyzing the focusing width of typical cross structure channel, a hydrodynamic focusing chip was designed. The effects of exposure time and single layer thickness on whole curing time was studied, the factors affecting the surface roughness were investigated, and the dimensional accuracy control method was proposed. The effect of bonding pressure on cured resin temperature was calculated and tested. The focusing width was verified by theoretical calculation and experiment. The mechanism for the inconsistency between the experimental focusing width and the theoretical focusing width was analyzed. The research proposed a solution of microfluidic design, fabrication, bonding and testing, which could provide a theoretical and methodological support for the efficient fabrication of microfluidic chips.

A series of Ni-based catalysts were prepared by the alcohol-promoted impregnation for CO2 reforming of methane. In order to illuminate the effects of carbon chain numbers and hydroxyl group numbers on the catalytic performance and coke resistance of Ni-based catalysts, the samples were characterized by XRD, SEM, BET, H2-TPR, FT-IR, XPS, TG, and TEM. The results show that the introduction of alcohol during impregnation promotes Ni2+ species into the channels of MCM-41, thereby strengthening the meatal-support interaction. Besides, the presence of alcohol decreases the particle size of Nickel and increases the surface adsorbed oxygen species over the surface of the support, thus promoting the coke resistance of the catalysts. As a consequence, NM-EG shows the highest catalytic performance, the highest stability, and the best coke resistance in all of the catalysts. This indicates that the main factor influencing the catalytic performance and coke resistance of the catalysts is the number of hydroxyl groups rather than the chain length of the introduced alcohol in the alcohol-promoted impregnation.

This brief paper reported an Ag/Al₂O₃ catalyst of high catalytic performance in C₃H6-SCR (selective catalytic reduction with C₃H6 as the reducer), and demonstrated a new strategy for the preparation of high active Ag/Al₂O₃ catalyst by the coupling co-precipitation and impregnation method. The results show that the coupling co-precipitation and impregnation catalyst was higher active than the usual impregnated catalyst in C₃H6-SCR of NO with broad active temperature window (420-600 °C), and the highest conversions of NO achieved 91% over the coupling co-precipitation and impregnation catalyst at 500 °C. The porous structure parameter, crystal phase structure, surface acidity property and particle morphology of the Ag/Al₂O₃ catalyst were characterized by the Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis spectra and temperature programmed desorption of ammonia (NH₃-TPD), respectively. Based on the characterization, it is found that the catalyst prepared by the coupling co-precipitation and impregnation method has smaller particles and better dispersion than the usual impregnated catalyst, and so the catalyst exhibited excellent catalytic activity. NH₃-TPD results illustrate that the weak and medium-strong acid sites is conducive to the reactivity of catalyst.

NOx, as the main air pollutant in the atmosphere, its elimination has attracted wide attention. Several technologies for eliminating NOx have been investigated by some researchers, and the selective catalytic reduction (SCR) of NOx with hydrocarbons has been proven to be an efficacious denitrification technology. Studies have suggested that excellent catalytic performances at low temperatures can be obtained over copper-based zeolite catalysts for HC-SCR. This review summarized the development of copper-based zeolite catalysts for HC-SCR and elaborated the synthesis methods, low-temperature catalytic performance, and reaction mechanism of the catalysts with different compositions and structures. The purpose of this review is to highlight (1) the structure–activity relationship of copper-based zeolite catalysts; (2) the main factors affecting the low-temperature catalytic activity; (3) the HC-SCR reaction mechanism of the copper-based zeolite catalysts; and (4) the design strategies for the copper-based zeolite catalysts with excellent low-temperature catalytic activity for HC-SCR.

This paper proposed a rapid fabrication process for polymethylmethacrylate (PMMA) microfluidic mixer chip by non-isothermal method based on resistance heating principle, and the prepared microfluidic mixer chip was successfully applied to the portable pesticide residue detection device. Firstly, the creep test of PMMA was carried out and the six units Maxwell constitutive model was fitted by Prony series. Secondly, the resistance heating device was designed, the influence of current on heating temperature and heating time was investigated, the effect of current on energy consumption was analyzed. Thirdly, the non-isothermal molding simulation and experiment of PMMA were carried out, the quality of PMMA microfluidic mixer chip fabricated by non-isothermal molding was investigated. Finally, the microfluidic mixer chip was adopted to the designed pesticide residue detection device, and the detection sensitivity of the device is 0.0375 mol−1. The research results provide a reference for the efficient preparation of microchannels and the development of portable detection equipment.

The effects of cemented carbide materials on cutting edge fracture mechanism of micro end mills in aluminum alloy 7075 machining are investigated. A series of micro milling experiments on the tool wear were conducted. The surface morphologies of micro end mills were observed, and the end teeth flank wear length and tool total cutting edge length reduction were measured. The results showed that the Co content and WC grain size of cemented carbides have significant effects on tool wear and cutting performance of the micro end mill. With increase of WC grain size, the tool end teeth flank wear length increases and the total cutting edge length reduction of the mill obviously increases. Thus, the micro end mill with finer grain size presents better wear resistance. However, with increase of Co content, the micro end mill exhibits less wear resistance. This can be explained that the adsorption energy between Co atom and Al atom become larger based on first principle calculation of adsorption energy between cemented carbides and aluminum alloy. The Co binder of tool material is dragged off by frequent fall off of built-up edge, resulting in more loss of Co element. Thus, the strength of the tool is decreased.

We demonstrated a new strategy for the preparation of highly stable mesoporous molecular sieves (TMM) by the desilication of MOR zeolite and self-assembling of the zeolite subunits in Na2O•(3.3–3.4) SiO2 aqueous solution. Na2O•(3.3–3.4) SiO2 in the aqueous solution plays two roles in the synthesis, one was providing a moderate alkaline medium with buffering effect for the desilication of MOR zeolite, other one was supplementing silica source. The desilication conduction of MOR zeolite was optimized by the adjustment of reaction temperature and time, pH in the solution. TMM were characterized by X-ray diffraction (XRD), N2 adsorption/desorption (BET), Fourier transformed infrared (FT-IR) and transmission electron microscopy (TEM). The characterization results showed that the characteristics of MOR zeolite, such as double six-membered or five-membered ring subunits, were still preserved in TMM, and TMM possessed well-ordered mesostructure of MOR zeolite crystals. Compared with the pure silica mesoporous molecular sieve (MCM-41, 4-day), the hydrothermal stability of TMM (17-day) was increased by 100% with refluxed water. The significantly improving of TMM hydrothermal stability was due to increase the surface hydrophobicity and the ratio of T12-ring, and decreased remarkably number of hydrophilic silanol groups. After hydrothermal treatment for 17-day, TMM also exhibited more efficient catalytic activation than MCM-41 treated for 4-day in CO2 reforming of methane reaction (700 °C). The 5 wt% Ni/TMM-17d-Glu (5 wt% Ni, loading) catalysts prepared by Glucose modified impregnation method exhibited excellent catalytic activity, which were providing 58% CO2 and 47% CH4 conversions at 700 °C.

NOX is a major atmospheric pollutant that is emanated by motor vehicles, thermal power plants, and industrial boilers. Therefore, the removal of NOX is a research hotspot in the exhaust gas treatment field. Numerous methods have been used to eliminate NOX: the selective catalytic reduction of NOX using C3H6 as the reducing agent (C3H6-SCR) is an effective method to remove NOX. The key issue in NOX removal in C3H6-SCR is to obtain catalysts with low-temperature activity and wide operating temperatures. Till date, different supported wide-temperature-active molecular sieve catalysts have been prepared and used in C3H6-SCR reactions. Studies have shown that the catalytic performance of supported catalysts is related not only to the active component but also to the structural and textural parameters of the molecular sieve supports. This review summarizes the structural and textural characteristics, catalytic properties, and catalytic mechanism of molecular sieve catalysts with different pore structures for C3H6-SCR reactions. The design strategies of supported molecular sieve catalysts are suggested. The goal of this review is to highlight (1) the structural and textural characteristics and low-temperature catalytic performance of different supported molecular sieve catalysts; (2) the relationship between wide-temperature window and loaded active components, as well as carriers of the supported molecular sieve catalysts; and (3) design strategies and development prospects of supported molecular sieve catalysts with low-temperature activity and wide-temperature operating range for C3H6-SCR reactions.

The elimination or degradation of nitrogen oxides, the major pollutants of the atmosphere, has been attracted extensive attention. Numerous methods have been studied and used to eliminate the nitrogen oxides, and the selective catalytic reduction (SCR), using ammonia as the reducing agent, is an effective method to remove nitrogen oxides. The studies show that the vanadium-based catalysts for NH3-SCR have the advantage of wide operation temperature windows and superior low temperature activity in reduction of NOX in the oxidizing atmosphere. This review summarized the development of the multi-metal vanadium-based catalysts for NH3-SCR, and elaborated the kinds of support and promoters, the catalytic function and mechanism, and the synthesis methods of vanadium-based catalysts for NH3-SCR. The purpose of this review is to highlight: (1) the structure-activity relationship for the vanadium-based catalysts; (2) the NH3-SCR mechanism of vanadium-based catalysts; and (3) the design strategies of the catalysts as superior low-temperature activity and wide-temperature vanadium-based in the field of NH3-SCR technique.

The excessive pesticide residues in cereals, fruit and vegetables is a big threat to human health, and it is necessary to develop a portable, low-cost and high-precision pesticide residue detection scheme to replace the large-scale laboratory testing equipment for rapid detection of pesticide residues. In this study, a colorimetric device for rapid detection of organophosphorus pesticide residues with high precision based on a microfluidic mixer chip was proposed. The microchannel structure with high mixing efficiency was determined by fluid dynamics simulation, while the corresponding microfluidic mixer chip was designed. The microfluidic mixer chip was prepared by a self-developed liquid crystal display (LCD) mask photo-curing machine. The influence of printing parameters on the accuracy of the prepared chip was investigated. The light source with the optimal wavelength of the device was determined by absorption spectrum measurement, and the relationship between the liquid reservoir depth and detection limit was studied by experiments. The correspondence between pesticide concentration and induced voltage was derived. The minimum detection concentration of the device could reach 0.045 mg·L−1 and the average detection time was reduced to 60 s. The results provide a theoretical and experimental basis for portable and high-precision detection of pesticide residues.

Hg2+ ions are highly toxic and bioaccumulative pollutant that can lead to adverse toxicological effects on environment and human health, and the establishment of simple and sensitive methods for the detection of trace Hg2+ ions is thus of great significance. On the basis of a new metal ion-triggered and DNA-fueled molecular machine strategy, we have established a sensitive and convenient approach for detecting Hg2+ in different water samples without involving in any enzymes or nanomaterials for signal enhancement. The target Hg2+ ions associate with the DNA complex probes through the formation of specific thymine-Hg2+-thymine (T-Hg2+-T) mismatched base pairing, which results in the release of the fluorescently quenched ssDNA from the complex probes to expose the pre-blocked toeholds. Subsequently, the fuel DNA further binds to the toeholds and triggers the operation of the molecular machine via strand displacement reactions to recycle the target ions, leading to the release of many fluorescently quenched ssDNAs for amplified monitoring of Hg2+ within the dynamic range of 0.1–100 nM with a detection limit of 65 pM. Besides, with specific T-Hg2+-T coordination, the established approach shows high selectivity to the target ions and can be employed to detect Hg2+ in tap and river water samples.

The construction of reliable sensors for adenosine triphosphate (ATP) detection gains increasing interest because of its important roles in various enzymatic activities and biological processes. Based on a cascaded, significant signal amplification approach by the integration of the aptazymes and catalytic hairpin assembly (CHA), we have developed a sensitive electrochemical sensor for the detection of ATP. The target ATP leads to the conformational change of the aptazyme sequences and their association with the hairpin substrates to form active aptazymes, in which the hairpin substrates are cyclically cleaved by the metal ion cofactors in buffer to release the enzymatic sequences that can also bind the hairpin substrates to generate active DNAzymes. The catalytic cleavage of the hairpin substrates in the aptazymes/DNAzymes thus results in the generation of a large number of intermediate sequences. Subsequently, these intermediate sequences trigger catalytic capture of many methylene blue-tagged signal sequences on the electrode surface through CHA, producing significantly amplified current response for sensitive detection of ATP at 0.6nM. Besides, the developed sensor can discriminate ATP from analogous interference molecules and be applied to human serum samples, making the sensor a useful addition to the arena for sensitive detection of small molecules.

Cerium(III) complexes of two ligands of a diaza-crown ether with different functional groups as side arms were synthesised and characterised. The catalytic ability of the cerium(III) complexes for pUC19 DNA cleavage was investigated and compared using agarose gel electrophoresis. The results indicate that the catalytic activity of the complex CeL2 [L2 = 2,2′- (1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl) diacetamide] with two carbamoylmethyl groups is significantly higher than the complex CeL1 [L1 = 2,2′- (1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl) diethanol] with two hydroxyethyl groups under the same conditions. The optimum catalytic concentrations of CeL1 and CeL2 were 7.69 × 10−5 and 3.08 × 10−5 mol L−1 respectively and excessively high concentrations of the complexes can reduce their catalytic efficiency due to the formation of inactive μ-hydroxo dimers. The optimum catalytic acidities of CeL1 and CeL2 were pH 7.0 and 7.5 respectively and excessively high pH of the reaction system can reduce the catalytic efficiency of the complexes due to the formation of cerium(III) hydroxide. DNA cleavage promoted by the two complexes takes place via the same hydrolytic pathway and so the activity difference of the two complexes is attributed to the stability of the complexes, rather than the catalytic mechanism.

We demonstrated a new strategy for the preparation of highly stable mesoporous molecular sieves (TZM) by the desilication of ZSM-5 zeolite and self-assembly of the zeolite subunits in a Na2O·(3.3–3.4) SiO2 aqueous solution. Na2O·(3.3–3.4) SiO2 in the aqueous solution plays two roles in the synthesis, one is providing a moderate alkaline medium with a buffering effect for the desilication of ZSM-5 zeolite, and the other one is supplementing the silica source. The desilication of ZSM-5 zeolite was optimized by the adjustment of reaction temperature and time, and pH of the solution. TZM were characterized by X-ray diffraction (XRD), N2 adsorption/desorption (BET), Fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). The characterization results show that the characteristics of ZSM-5 zeolite, such as double six-membered or five-membered ring subunits, were still preserved in TZM, and TZM possessed the well-ordered mesostructure of ZSM-5 zeolite crystals. Compared with the pure silica mesoporous molecular sieve (Si-MCM-41, 4 days), the hydrothermal stability of TZM (8 days) was increased by 100% in refluxed water. The significant improvement of TZM hydrothermal stability was due to an increase of the surface hydrophobicity and the ratio of 5-rings or 6-rings, and a remarkable decrease in the number of hydrophilic silanol groups. After hydrothermal treatment for 8 days, TZM also exhibited a more efficient catalytic activation than Si-MCM-41 treated for 4 days in the CO2 reforming of methane reaction at 1023 K (750 °C). The 5% Ni/TZM-8-Glu (5 wt% Ni, loading) catalyst prepared by a glucose modified impregnation method exhibited excellent catalytic activity, which provided 73% CH4 and 72.5% CO2 conversion at 1023 K (750 °C).

Single-point diamond cutting is an efficient method to generate the V-shape microgrooves, but the burr forms easily at the microgroove edge when cutting ductile material, especially at small (micron level) cutting depth, and the burr increases with the reduction in the cutting depth. In this paper, the effects of plastic side flow in micro cutting are taken into account to explain the formation of burrs in ultraprecision machining process. The edge radius of diamond tool is measured by scanning probe microscope (SPM), and the mechanism of the burr formation is revealed with considering the edge radius of diamond tool and the cutting depth in machining nickel phosphide (Ni-P). In this way, an approach to restrain the burr formation is established so as to generate fine microgrooves.

The determination of the level of Cu2+ plays important roles in disease diagnosis and environmental monitoring. By coupling Cu+-catalyzed click chemistry and metal ion-dependent DNAzyme cyclic amplification, we have developed a convenient and sensitive colorimetric sensing method for the detection of Cu2+ in human serums. The target Cu2+ can be reduced by ascorbate to form Cu+, which catalyzes the azide-alkyne cycloaddition between the azide- and alkyne-modified DNAs to form Mg2+-dependent DNAzymes. Subsequently, the Mg2+ ions catalyze the cleavage of the hairpin DNA substrate sequences of the DNAzymes and trigger cyclic generation of a large number of free G-quadruplex sequences, which bind hemin to form the G-quadruplex/hemin artificial peroxidase to cause significant color transition of the sensing solution for sensitive colorimetric detection of Cu2+. This method shows a dynamic range of 5 to 500 nM and a detection limit of 2 nM for Cu2+ detection. Besides, the level of Cu2+ in human serums can also be determined by using this sensing approach. With the advantages of simplicity and high sensitivity, such sensing method thus holds great potential for on-site determination of Cu2+ in different samples.

Chalcogenide glass (ChG), as an alternative material in place of single-crystal germanium, is increasingly used in thermal imaging, night vision, and infrared guidance systems, etc., owing to their excellent formability through precision glass molding (PGM). The deformation mechanisms of these glasses at the molding temperature involve elasticity, plasticity, and viscous flow, which call for a new theoretical model to assist the design of PGM process. This paper investigates the thermo-mechanical properties of Ge22Se58As20 at the temperature above its softening point and establishes a new elastic-viscoplasticity model to describe its thermo-mechanical behaviors. After determining the model parameters through cylindrical compression tests, the new constitutive model is implemented in finite element method (FEM) of PGM to form an aspheric ChG lens. And the agreement of displacement-time curves between experimental and simulation results exhibit the validity of the proposed elastic-viscoplastic constitutive model.

The construction of simple and highly sensitive aptasensors will significantly advance the monitoring of proteins. In this work, we have developed a convenient and label-free protein-induced catalytic hairpin assembly signal amplification approach for aptamer-based sensitive electrochemical detection of thrombin in human serums. The target thrombin binds the aptamer-containing hairpin probes immobilized on the sensor electrodes and triggers catalytic assembly of other two hairpins to form many G-quadruplex Y-junction DNA structures in situ . These G-quadruplex structures further associate with hemin to form G-quadruplex/hemin complexes, which are then subject to electrochemical measurement and generate substantially amplified current output for label-free and sensitive detection of thrombin. The developed aptasensor shows a dynamic range of 0.01–1.0 nM and a detection limit of 6.0 p.m for thrombin detection. The sensor can also discriminate the target thrombin against other non-target proteins and exhibits promising results for detecting thrombin in human serums. With the successful construction of the thrombin aptasensor, our signal amplified method can be potentially applied to detect other target molecules by choosing appropriate aptamer/ligand pairs.

We report the synthesis, catalytic function and catalytic mechanism of two transition metal complexes (CuL, ZnL) of a diaza-crown ether with two acetylamino side arms [L = 2,2′-(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)diacetamide] in the hydrolysis of DNA. Their nuclease functions on pUC19 DNA cleavage were investigated. The results indicated that the active species might be formed by the deprotonation of the water-coordinated molecules in the complex and the optimum pH is 8.0 for both CuL and ZnL. The catalytic activity of CuL is higher than that of ZnL in DNA hydrolytic cleavage due to the difference in the Lewis acidity of the central metal ions, which is contrary to the result with the Cu and Zn complexes of the parent ligand L0 (1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) as artificial nuclease. Comparison studies of DNA cleavage in the presence and absence of several oxygen scavengers showed that these complexes can promote DNA cleavage by a hydrolytic pathway. Our proposed mechanism suggests that the negative charge on the phosphorus oxygen atom of the substrate molecule is dispersed and the intermediate is formed and stabilised by hydrogen bonding between the DNA molecule and the acetylamino group of the complex.

Optical microstructures are increasingly applied in several fields, such as optical systems, precision measurement, and microfluid chips. Microstructures include microgrooves, microprisms, and microlenses. This paper presents an overview of optical microstructure fabrication through glass molding and highlights the applications of optical microstructures in mold fabrication and glass molding. The glass-mold interface friction and adhesion are also discussed. Moreover, the latest advancements in glass molding technologies are detailed, including new mold materials and their fabrication methods, viscoelastic constitutive modeling of glass, and microstructure molding process, as well as ultrasonic vibrationassisted molding technology.

Because of their irreversible toxicological impacts on the environment and human body, the development of reliable and sensitive Hg2+ detection methods with high selectivity is of great significance. On the basis of the substantial signal amplification by metallo-toehold-triggered, catalytic hairpin assembly (CHA) formation of three-way DNAzyme junctions, we have constructed a highly selective and sensitive fluorescent sensing system for the determination of Hg2+ in different environmental water samples. The presence of the target Hg2+ ions can lead to the generation of T-Hg2+-T base mismatched metallo-toeholds, which trigger the catalytic assembly of three split-DNAzyme containing hairpins to form many Mg2+-dependent DNAzyme junction structures upon binding to the fluorescently quenched substrate sequences. The Mg2+ ions then cyclically cleave the fluorescently quenched substrate sequences of the Mg2+-dependent DNAzymes to generate drastically enhanced fluorescent signals for sensitively detecting Hg2+ a...

Micro optical elements with complex shapes are needed increasingly in optical, optoelectronic and biomedical industries. Since glass molding process is an effective approach to fabricate microstructures, and its surface quality strongly depends on the filling capacity of glass at high temperature. To improve the formability and reduce adhesion between the glass and the mold at high temperature, ultrasonic vibration is applied to improve the formability in the molding process. Fundamental experiments are carried out to test the effectiveness of ultrasonic vibration on friction force decrease and a bonding model on the glass-mold interface at elevated temperature is proposed. Finite element method (FEM) simulation and glass molding experiments are conducted to evaluate the improvements of material formability brought about by ultrasonic vibration. The results show that the ultrasonic vibration can significantly lower the friction force and increase the glass formability.

Two diaza-crown ether compounds, 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (L0) and its derivative with double acetamide side arms 2,2'-(1,4,10,13-teteaoxa-7,16-diazacyclooctadecane-7,16-diyl)diacetamide (L), and the corresponding two lanthanum complexes were synthesised and characterised. The catalytic capacity of the lanthanum complexes was investigated for the hydrolysis of bis(4-nitrophenyl) phosphate ester (BNPP) in aqueous solution and in CTAB micelles. Kinetic studies show that the catalytic efficiency of complex LaL is obviously higher than that of complex LaL0, and introducing acetamide into the ring of the diaza-crown ether can improve the catalytic ability of the complexes for BNPP hydrolysis. A rate enhancement of about two times was observed for the complex–micelle in contrast with the complex–water system for BNPP catalytic hydrolysis. The optimal pH for the catalytic reaction in the two kinds of media systems show an approximately 0.4 pH unit difference. The two complexes possess higher thermostability, and are more stable in the micelle than in aqueous solution. Based on the results and their analysis, a catalytic mechanism with cooperation of acetamide is proposed.

In this work, a three-dimensional large-deformation thermo-elastic-plastic finite element model for oblique cutting was established to analyze edge defects during the machining of 17vol.% SiCp/2009Al composites. The formation process of edge defects at the workpiece exit during turning was investigated, and the influence of depth of cut, feed rate, and spindle speed on the edge defect sizes at the workpiece exit was explored. The results show that a negative deformation plane began to form as the cutting tool approached the exit end of cut, and the resultant cracks propagated towards the negative shear deformation plane, which led to workpiece edge defects. In addition, the size of edge defects increased with increasing depth of cut and feed rate, while the spindle speed had less influence on the size of edge defects. The numerical results of the effects of cutting parameters on edge defects were also compared to those of the turning experimental data, and were found to be in reasonable agreement.

This brief paper reported an Ag/Al₂O₃ catalyst of high catalytic performance in C₃H

S100 calcium‑binding protein A9 (S100A9), a member of the S100 protein family, is often upregulated in various cancers, including cervical cancer. Elevated S100A9 expression is thought to serve an important role in tumorigenesis; however, the exact role of S100A9 in the modulation of cervical cancer and the underlying molecular mechanism remain unknown. In the present study, we aimed to investigate the effects of S100A9 on the proliferation and migration of cervical cancer cells, as well as the molecular mechanisms underlying these effects. Our results demonstrated that endogenous expression of S100A9 in SiHa and CaSki cell lines was significantly higher than in the HeLa cell line. As expected, overexpression of S100A9 enhanced the proliferation and migration of cervical cancer cells. In addition, S100A9 overexpression induced epithelial‑mesenchymal transition (EMT) as determined by reduced expression levels of the epithelial marker E‑cadherin, whereas the expression levels of the mesenchymal marker vimentin were upregulated. Furthermore, it was reported that the effects of S100A9 in the modulation of cervical cancer cells were mediated through the Wnt/β‑catenin signaling pathway as β‑catenin knockdown significantly suppressed the ability of S100A9 to enhance the proliferation and migration of cervical cancer cells. Collectively, these findings suggest that S100A9 promoted the proliferation and migration of cervical cancer cell lines. Furthermore, the underlying molecular mechanisms may be partially attributed to the induction of EMT and activation of the Wnt/β‑catenin signaling pathway.

To manufacture high precision optical glass microstructures, finite element simulation and experiments of precision glass molding (PGM) are carried out to study the influence of relaxation effect on internal stress and deformation of the glass material. Two kinds of microstructures including microgrooves and micropyramids are fabricated by PGM. First, a two-dimensional axisymmetric finite element model of the PGM is established, and three kinds of molding schemes are put forward and analyzed, including quick molding and holding for a period of time, molding with low speed, molding by gravity. The advantages and disadvantages of the three schemes are also analyzed. Second, the microgrooves are fabricated using the scheme of molding by gravity, and then the existing problems are discussed. Finally, the micropyramids are fabricated by the low speed molding method, and the forming profiles are compared.

Ensuring occupants’ thermal comfort and work performance is one of the primary objectives for building environment conditioning systems. In recent years, there emerged many occupant-orientated technologies aiming to optimize thermal comfort while saving energy. These attempts offered opportunities to move the indoor thermal environment control from the one-fits-all approach toward a new paradigm with occupant-centric merits. A timely review of this emerging field would help to fill the knowledge gap and provide new insights for future research and practice. This study performed a literature review to summarize recent occupant-centric thermal comfort practices following a framework with three themes: sensing, predicting, and controlling. The results show that occupant-centric thermal comfort control has become a hot research topic in recent years. A wide range of variables and data-collecting sensors were utilized to support the concept. Among all the potential variables, occupants’ comfort feedback, skin temperature, and air temperature are the top three popular input features for thermal comfort prediction. Using different machine learning algorithms, data-driven thermal comfort models were reported to have a median predicting accuracy of 84% and some of them can predict thermal comfort at a personal level. Cases implementing occupant-centric thermal comfort control strategy were reported to save air-conditioning energy by 22% and improve thermal comfort by 29.1%. These observations from the literature support the prospects of the new thermal comfort paradigm. Additionally, the challenges and opportunities in this emerging field were discussed.

Microgrooves with a pitch at wave length level are increasingly needed in the optical system. Conventionally, the accuracy is low in microgroove forming due to the incomplete filling in the cavity of microgroove mold, as well as the surface flaws appearing with the adhesion of the resin material to the mold surface. In this research, the response behavior of resin material subjected to alternating stress is resolved based on Generalized Maxwell model. Finite Element Method (FEM) simulation is carried out to test the interface contact between the resin and the mold. Microgrooves forming effects under the pressing condition without and with ultrasonic vibration are studied. An ultrasonic vibration assisted pressing machine is developed and used to fabricate microgrooves on resin surface by using the Nickel Phosphorous (Ni–P) mold. The results show that the ultrasonic vibration can significantly decrease the resin dynamic viscosity as well as contact time with the mold, and achieve better forming accuracy and surface quality.

A new diaza-crown ether with double hydroxypropyl branches (L = 1,1'-(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)dipropan-2-ol) and its two lanthanide complexes (LaL and CeL) were synthesised and characterised. Their nuclease activities on pUC19 DNA cleavage were investigated using agarose gel electrophoresis, and pseudo-first-order rate constants kobs of 0.067 h–1 for LaL, 0.041 h–1 for CeL, 0.013 h–1 for LaL0, and 0.027 h–1 CeL0 were obtained (L0 = 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane). The results indicated that the CeL complex was more efficient than the LaL complex for DNA cleavage at low concentrations, but the LaL complex was more efficient than the CeL complex at high concentrations. Moreover, kinetic studies demonstrated that introducing hydroxypropyl side arms in the ring of the diaza-crown ether can improve the catalytic ability of the complexes in DNA cleavage, which may be due to the hydroxypropyl side arms enhancing the bonding interaction between the complex and the DNA molecule by hydrogen bonding. A hydrolytic mechanism for DNA cleavage was demonstrated by applying several oxygen scavengers to the DNA catalytic cleavage. A proposed mechanism for the DNA cleavage shows that the hydroxypropyl side groups can recognise and bind the phosphodiester bond of DNA by hydrogen bonding and electrostatic interaction.

Based on the unique characteristics of lanthanum ion and aza-crown ethers, the lanthanum complexes of two aza-crown ether (L1: 1,10-Dioxa-4,7,13,16-tetraazacyclo-octadecane and L2: 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) were designed and synthesised. The interaction between these two complexes and DNA was measured by UV-Vis spectroscopy and gel electrophoresis. Moreover, a series of experiments of cleavage of pUC19 DNA were conducted to illustrate the acidity, time and concentration effects. The results indicated that the two metal complexes can accelerate the breakage of DNA from its supercoiled form (form I) to the nicked form (form II) at near-physiological conditions, and the optimum acidity of DNA catalytic cleavage is pH=6.5 and pH=7.0 for LaL1 and LaL2, respectively. Furthermore, the LaL1 exhibited better cleavage activity than LaL2 under the same conditions, thus supercoiled DNA was thoroughly cleaved to the nicked form under the appropriate conditions. The hydrolytic mechanism was verified by applying several oxygen-scavengers to the DNA catalytic cleavage.

Predicting building occupants’ thermal comfort via machine learning (ML) is a hot research topic. Many algorithms and data processing methods have been applied to predict thermal comfort indices in different contexts. But few studies have systematically investigated how different algorithms and data processing methods can influence the prediction accuracy. In this study, we first summarized the recent literature from perspectives of predicted comfort indices, algorithms applied, input features, data sources, sample size, training proportion, predicting accuracy, etc. Then, we applied nine ML algorithms and three data sampling methods to predict the 3-point and 7-point thermal sensation vote (TSV) in ASHRAE Comfort Database II. The results show that with an accuracy of 66.3% and 61.1% for 3-point and 7-point TSV respectively, Random Forest (RF) has the best performance among the tested algorithms. Compared to the Predicted Mean Vote (PMV) model, ML TSV models generally have higher accuracy in TSV prediction. Based on feature importance analysis, the air temperature, humidity, clothing, air velocity, age, and metabolic rate are the top six important features for TSV prediction. The RF algorithm can achieve 63.6% overall accuracy in TSV prediction with the top three features, which is only 2.6% lower than involving 12 input features. Further, this paper addressed other common considerations in ML comfort model establishment such as tuning hyperparameters, splitting of training and testing data, and encoding methods. We also provided Python and R programming codes and packages as appendixes, which can be a good reference for future studies.

A catalyst V-Ce-Ni/TiO2 was synthesized using the ultrasound-assisted impregnation, and the catalysts V-Ce-Ni/TiO2-NP and V-Ce-Ni/TiO2-HP were prepared by N2 and H2 non-thermal plasma-treatment, respectively. The structure and catalytic activity of the catalysts was characterized and evaluated in the study. BET results indicated that the specific surface area over V-Ce-Ni/TiO2-NP catalyst (50 m2·g−1) was higher than that of untreated catalyst (49 m2·g−1). And the characterization results of XRD, TEM, SEM and EDS showed that the plasma treated catalysts have smaller particle size, higher dispersion and better uniform distribution of active sites on the catalyst surface than the untreated catalyst. Besides, the results of XPS and NH3-TPD revealed that non-thermal plasma treatment generated more oxygen vacancy on the catalyst surface than the untreated catalyst, and then increased the amount of acid sites. H2-TPR results suggested that the interaction between active components and support (TiO2) of V-Ce-Ni/TiO2-HP was stronger than that of V-Ce-Ni/TiO2-NP. The results of NH3-SCR (selective catalytic reducing of NO with ammonia) showed that above 90% of NO conversion was obtained over V-Ce-Ni/TiO2-HP catalyst in the temperature ranging from 195 °C to 414 °C, and 100% of NO conversion was maintained in the temperature regions of 230 °C to 350 °C. The catalytic activity of the catalysts of non-thermal plasma treatment was enhanced at low temperature (below 260 °C), and the operating temperature window (T90) of the catalysts was widened.

Hot embossing is an efficient technique for manufacturing high-quality micro-lens arrays. The machining quality is significant for hot embossing the micro-lens array mold. This study investigates the effects of micro ball end-milling on the machining quality of AISI H13 tool steel used in the micro-lens array mold. The micro ball end-milling experiments were performed under different machining strategies, and the surface roughness and scallop height of the machined micro-lens array mold are measured. The experimental results showed that a three-dimensional (3D) offset spiral strategy could achieve a higher machining quality in comparison with other strategies assessed in this study. Moreover, the 3D offset spiral strategy is more appropriate for machining the micro-lens array mold. With an increase of the cutting speed and feed rate, the surface roughness of the micro-lens array mold slightly increases, while a small step-over can greatly reduce the surface roughness. In addition, a hot embossing experiment was undertaken, and the obtained results indicated higher-quality production of the micro-lens array mold by the 3D offset spiral strategy.