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In this study, zirconium alloys were analyzed for their phase transformation behavior and kinetics in the presence of non-isothermal conditions through differential scanning calorimetry. The phase transition temperature was examined on the differential thermal curves. Indeed, it was affected by heating rates, and the equilibrium transformation temperature of the alloy was extrapolated using a model approach. The α → β phase transformation activation energy was calculated using Kissinger–Akahira–Sunose as well as Flynn–Wall–Ozawa approach, and activation energy was related to conversion ratios, thus suggesting that phase transformation refers to the complicated multi-step reaction. Furthermore, the alloy transformation mechanism was discussed using the optimized Johnson-Mehl-Avrami.

The emergence of antibiotic resistance in bacteria is an urgent issue, especially in treating infectious diseases. Nowadays, bacterial infections draw great attention to research and develop new antibacterial agents, while less attention was paid to trade the old for the new. Levofloxacin, as one of quinolones, has broad-spectrum and strong antibacterial effect. However, the clinical employment of levofloxacin is limited for drug resistance. Herein, levofloxacin-based carbon dots (LCDs) with enhanced antibacterial activities and low drug resistance were synthesized via a simple one-pot hydrothermal method. Results indicated that LCDs possessed effective antibacterial property by preserving the active groups of the levofloxacin. LCDs provided the dual-antibacterial mode to collapse bacteria based on the positive surface charge and the production of reactive oxygen species simultaneously. In addition, the in vitro and in vivo experiments suggested that the LCDs displayed excellent antibacterial activity and biocompatibility, as reflected by the improved curative effect in animal infected models and selectively eliminating bacteria over mammalian cells and tissues. Consequently, this work highlights the potential application of the above-mentioned LCDs with improved broad-spectrum antibacterial activity and resistance to drug resistance as an antibacterial nanomaterial on the field of antibacterial medicine.

The Singaporean government has made building information modeling (BIM) implementation mandatory in new building projects with gross floor areas over 5000 m2, but the implementation is still plagued with hindrances such as lacking project-wide collaboration. The purposes of this study are to identify critical factors hindering BIM implementation in Singapore&rsquo, s construction industry, analyze their interrelationships, and identify strategies for reducing these hindrances. The results from a survey of 87 experts and five post-survey interviews in the Singaporean construction industry identified 21 critical hindrances, among which &ldquo, need for all key stakeholders to be on board to exchange information&rdquo, was ranked top. These hindrances were categorized into lack of collaboration and model integration (LCMI), lack of continuous involvement and capabilities (LCIC), and lack of executive vision and training (LEVT). LEVT and LCIC contributed to LCMI, LEVT caused LCIC. The proposed framework implying the key hindrances and their corresponding managerial strategies can help practitioners identify specific adjustments to their BIM implementation activities, which enables to efficiently achieve enhanced BIM implementation. The hindrances identified in this study facilitate overseas BIM implementers to customize their own lists of hindrances.

In this paper, two 3D anionic metal–organic frameworks, [(CH3CH2)2NH2]·[Zn(BTC)1/3(PyC)]·1/2CH3CN·2H2O (NKU-102) and [(CH3CH2)2NH2]·[Zn2(BTC) (PyC)]·1.5H2O·DEF (NKU-103), were constructed from the same reaction system at different temperature. Though both are of anionic framework, NKU-102 possesses a sealed 3D framework based on octahedral cage and shows negligible adsorption capacity of organic dyes, whereas NKU-103 features an open triangular microchannel surrounded by two types of helical chains, and thus exhibits outstanding size-selective adsorption toward small cationic organic dyes.

β-Li2TiO3 pebbles were fabricated by a modified indirect wet chemistry method. The first feature lies in that β-Li2TiO3 powders via hydrothermal method were used as raw materials. The second one lies in that a mixture of the acetone and carbon tetrachloride was used for formation and aging of the pebbles at room temperature. The phase identification of the β-Li2TiO3 sintered pebbles was conducted by the X-ray Diffraction analysis. The morphology of the sintered β-Li2TiO3 pebbles was observed by Field Emission Scanning Electron Microscope. The experimental results show that the β-Li2TiO3 pebbles with about 1.56 mm in diameter, a better sphericity of 1.02 and relative sintered density of 95.8%T.D. are successfully fabricated when sintered at 1100 °C for 6 h in ambient conditions. The grains in the pebbles are polyhedral brick-shaped, and homogeneous in size distribution. The morphology evolution and relative density of the β-Li2TiO3 pebbles are governed by the sintering temperature, between 1050 °C and 1150 °C. More homogeneous in grain size, less porosity, and higher densification of the β-Li2TiO3 pebbles can be obtained at 1100 °C.

The infinite dilution activity coefficients ( γ i ∞ ) and gas–liquid partition coefficients (KL) of solutes in the ionic liquids (ILs) are important parameters of thermodynamic properties. They can evaluate the separation selectivity ( S ij ∞ ) of ILs and screen out suitable extractants for difficult separation systems. The retention times of solutes in IL 1-propyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide [PMMIM][NTf2] were measured by gas chromatography (GC) to calculate the γ i ∞ and the ΚL values of organic solutes (eg. n-alkanes, alkyl benzenes, acetonitrile, tetrahydrofuran, ethyl acetate, etc.) in [PMMIM][NTf2] at 303.15 K-353.15 K. The density of [PMMIM][NTf2], as a function of temperature, was measured at p = 101.3 kPa. The values of the partial molar excess enthalpies at infinite dilution ( H - i E , ∞ ) were derived from the T dependence of the l n γ i ∞ . The entropies ( T ref S - i E , ∞ ) and Gibbs free energies ( G - i E , ∞ ) of organic solutes in [PMMIM][NTf2] at a reference temperature Τref = 298.15 K can be calculated from the γ i ∞ values. The Hildebrand’s solubility parameters of the IL [PMMIM][NTf2] were obtained from the regular solution theory (RST) combined with Flory “combinatorial” equation. At 323.15 K, the selectivity ( S ij ∞ ) of n-hexane (i)/benzene (j) and cyclohexane (i)/benzene (j) and the capacity ( k j ∞ ) at infinite dilution of benzene have been determined. The results were analyzed by comparing with literature data for alkylimidazolium-based ILs with [NTf2]−.

Luminescent copper nanoclusters (CuNCs) constitute a very active research topic due to their unique properties and lower cost than gold and silver NCs. In this study, we report a new, facile, and rapid top-down etching method for synthesizing luminescent CuNCs, using Cu nanoparticles (CuNPs) as the precursor and ammonia (NH3) as the etchant. The etching mechanism is systematically investigated and the optical and structural properties of the obtained CuNCs are carefully studied. The NH3-triggered etching process is very fast and the newly generated CuNCs can emit strong green fluorescence with a high quantum yield. Moreover, by coupling the urease-catalyzed hydrolysis of urea with the NH3-induced etching of CuNPs, we developed a novel fluorescence turn-on assay for urea. The linear range for urea detection is from 0.25 to 5 mM, and the limit of detection is 0.01 mM. This novel sensing approach, with good sensitivity and excellent selectivity, is then successfully utilized to detect urea in human serum samples, demonstrating its great potential in clinical diagnosis. In addition, the proposed coupling method can be extended to monitor other analytes that influence the size-focusing etching process, allowing metal NCs to be used to construct diverse chemosensors and biosensors.

The development of simple yet powerful methods for monitoring enzyme activity is of great significance. Herein, a facile, convenient, cost-effective, and continuous fluorescent method for the detection of arginase and its inhibitor has been reported based on a host-guest interaction-controlled and enzymatic hydrolysis-controlled luminescent nanoswitch. The fluorescence intensity of 6-aza-2-thiothymine-stabilized gold nanoparticle (ATT-AuNP) is enhanced by l-arginine, owing to the formation of a supramolecular host-guest assembly between the guanidine group of l-arginine and ATT molecules capped on the AuNP surface. However, hydrolysis of l-arginine, catalyzed by arginase, leads to a decrease in the fluorescence intensity of l-arginine/ATT-AuNPs hybrids. Upon incorporation of the arginase inhibitor l-norvaline, the fluorescence of the ATT-AuNP-based detecting system is restored. The linear range of arginase activity determination is from 0.0625 to 1.15 U/mL and the limit of detection is 0.056 U/mL. The half-maximal inhibition value IC

This paper presents the effects of Hall output probes shape on the magnetic characteristic of magnetic field sensors with Hall output probes, which is based on metal-oxide-semiconductor field effect transistor (MOSFET). The Hall sensor chips are fabricated on silicon substrates with high resistivity by using CMOS technology. Experiment results show that, when drain-source voltage VDS=5.0 V, the magnetic sensitivity of the magnetic field sensor with the concave Hall output probes and channel length-width ratios of 160 μm/80 μm, 320 μm/80 μm and 480 μm/80 μm are 53.3 mV/T, 32.54 mV/T and 20.32 mV/T, respectively. At the same condition, the magnetic sensitivity of the magnetic field sensor with convex Hall output probes and the channel length-width ratio of 160 μm/80 μm is 76.8 mV/T.

Capping molecules on the surface of nanomaterials not only enhance the dispersion and stability of nanomaterials but also greatly facilitate their surface modification and biological applications. However, most capping molecules can severely block the active sites of the catalytic core, thereby decreasing the enzymatic activity of nanomaterial-based enzyme mimics. This work demonstrates the superiority of chitosan (Ch) as a capping molecule for synthesizing catalytic platinum nanoparticles (PtNPs). The experimental results show that Ch simultaneously exhibits an excellent stabilizing effect and enhances the oxidase-like activity of PtNPs. Kinetic studies indicate that Ch-PtNPs have a higher affinity for 3,3′,5,5′-tetramethylbenzidine (TMB) than other kinds of oxidase mimics. Furthermore, the TMB chromogenic reaction catalyzed by Ch-PtNPs is found to be much faster in an acidic medium, thus adapting well to the optimal pH for acid phosphatase (ACP). Therefore, a novel colorimetric approach for ACP determination is developed for the first time, which is based on the Ch-PtNP-catalyzed oxidation of TMB, the inhibitory effect of ascorbic acid (AA) on the oxidase-like activity of Ch-PtNPs, and the ACP-catalyzed hydrolysis of AA 2-phosphate (AAP) into AA. The linear range for ACP is 0.25–2.5 U L−1 and the limit of detection is measured to be 0.016 U L−1. This new colorimetric method is utilized to detect ACP in real biological samples and to screen ACP inhibitors. We believe that these new PtNPs, which exhibit high colloidal stability, excellent catalytic performance, good biocompatibility, simple preparation, and easy modification, can be promising candidates for a broad range of applications in optical sensing, environmental monitoring, clinical diagnosis, and drug discovery.

Near-infrared light has significant advantages for light-triggered drug delivery systems within deep tissues. The use of inorganic nanomaterials raises concern over their long-term in vivo toxicities. Here we will highlight emerging near-infrared light-triggered drug delivery using organic nanomaterials, as well as new photocleavage reactions mediated by near-infrared light.

This work elucidated the valence states effect on the electrogenerated chemiluminescence (ECL) performance of gold nanocluster (AuNC). The N-acetyl-l-cysteine-AuNCs (NAC-AuNCs) and the electrochemical reduction method for reducing the AuNCs were first employed to this study. Results demonstrate that the electrochemical reduction degree of the AuNCs depended on the reduction potential, and the enhancement of the ECL signals was positively correlated with the reduction degree of AuNCs, which indicated that the valence state of Au plays a vital role in the ECL performance of AuNCs. Furthermore, the proposed method has been successfully extended to the chemical reduction technique and other nanoclusters. Therefore, an excellent AuNC-based ECL method with various advantages, such as simple preparation, lower toxicity, high sensitivity, and ΦECL, and excellent stability, has been proposed. This approach not only opens up a new avenue for designing and developing ECL device from other functional-metal based NCs,...

A novel platform for the fabrication of a glucose biosensor was successfully constructed by entrapping glucose oxidase (GOD) in a ferrocene (Fc)-branched organically modified silica material (ormosil)/chitosan (CS)/graphene oxide (GO) nanocomposite. The morphology, structure, and electrochemistry of the nanocomposite were characterized by transmission electron microscopy, X-ray powder diffraction, UV–vis spectroscopy, Fourier transform infrared spectroscopy, and electrochemical techniques. Results demonstrated that the proposed electrochemical platform not only provided an excellent microenvironment to maintain the bioactivity of the immobilized enzyme, but also effectively prevented the leakage of both the enzyme and mediator from the matrix and retained the electrochemical activity of Fc. Furthermore, dispersing GO within the Fc-branched ormosil/CS matrix could significantly improve the stability of GO and make it exhibit a positive charge, which was more favorable for the further immobilization of biomolecules, such as GOD, with higher loading. Moreover, it could also improve the conductivity of the matrix film and facilitate the electron shuttle between the mediator and electrode. Under optimal conditions, the designed biosensor to glucose exhibited a wide and useful linear range of 0.02 to 5.39 mM with a low detection limit of 6.5 μM. The value of K M app was 4.21 mM, indicating that the biosensor possesses higher biological affinity to glucose. The present approach could be used efficiently for the linkage of other redox mediators and immobilize other biomolecules in the process of fabricating novel biosensors.

Polycrystalline aluminum nitride (AlN) films were deposited on Si (111) substrates by radio frequency (RF) magnetron sputtering method in an nitrogen (N2) + argon (Ar) gas mixture. The effect of the preparation conditions- sputtering pressure (p), sputtering power (w), gas mixture (Ar/N2) and post-deposition annealing treatment -on the properties of AlN films were investigated by means of X-ray diffraction (XRD). Highly c-axis oriented AlN films were obtained with optimized growth parameters: p=0.3Pa, w=400w and Ar/N2=2.

Li-doped zinc oxide (ZnO) films were deposited on nucleation side of freestanding diamond (FSD) films by the radio frequency magnetron sputtering method. The effect of oxygen partial pressure on structural, optical and electrical properties of the ZnO films was investigated by X-ray diffraction (XRD) Raman spectroscopy, semiconductor characterization system and Hall effect measurement system. The results showed that the introduction of oxygen as a reactive gas was helpful to improve the crystalline quality of Li-doped ZnO films.

The classroom use of independent reading primarily grew out of concerns for students’ reading achievements. Various studies have indicated that engagement in Sustained Silent Reading (SSR) improves not only students’ reading skills but also their attitude towards reading itself, an activity that many rarely associate with pleasure. SSR is a programme based on the belief that self-selection, among other factors, motivates learners to read with interest and works towards helping them feel that reading is an oasis rather than a burden. In turn, this produced other benefits; beyond improving students’ attitude towards reading, silent reading programmes have also helped learners in terms of spelling, writing and vocabulary gains, as well as in developing their reading speed and reading comprehension skills ( Birmingham, 2006 , Gardiner, 2001 , Weller and Weller, 1999 , Arthur, 1995 , Dwyer and West, 1994 , Krashen, 1993 ). Although evidently advantageous to language learners, effective implementation of an SSR programme still depends largely on the discernments of those who stand to benefit the most from it. The results of this research specifically captures the perceptions of Universiti Sains Malaysia undergraduates with regards to SSR, and it is hoped that the information gained from these responses will assist in providing direction for educators who are interested in incorporating SSR into their respective literacy programmes.

Thermoelectric is an ever evolving field that serves many critical needs (cooling and power generation) in the industry. The key objective of this work is to fabricate Bismuth Telluride (Bi2Te3) thin-films by varying the various process parameters using a radio-frequency (RF) magnetron sputtering disposition technique. Characterization methods such as four point probe resistivity, surface profiler, atomic force microscopy (AFM), X-ray diffraction (XRD), Seebeck coefficient and thermal diffusivity are performed on the N and P-type Bi2Te3films. The samples are analysed for their electrical properties in relation to the evolved microstructures, for how the process parameters of sputtering and annealing affect these changes. The results demonstrate that N-Type film (S2) processed using sputtering parameters of 7mT, 100W, 50sccm of argon flow under room temperature for 30mins with no annealing and the P-Type film processed using sputtering parameters of 7mT, 100W, 60sccm under room temperature for 30mins with institute annealing at 200°C for 2h exhibit desirable thermoelectric properties suitable for cooling application in microelectronic and optoelectronic devices, optimizing their performance and reliability.

A simple, rapid, sensitive, and accurate method for simultaneous electrochemical determination of procaine and its metabolite (p-aminobenzoic acid, PABA) for pharmaceutical quality control and pharmacokinetic research was developed using a graphite paste electrode. The differential pulse voltammetric results revealed that procaine and p-aminobenzoic acid, respectively, showed well-defined anodic oxidation peaks on a carbon paste electrode with a current peak separation of 155 mV at a scan rate of 100 mV s−1. This well separation of the current peaks for these two compounds in voltammetry enables us to simultaneously determine them. Good linearity (r > 0.998) between oxidation peak current and concentration was obtained in the range of 5.0 × 10−7–5.0 × 10−5 M for procaine and 5.0 × 10−7–2.0 × 10−5 M for PABA in pH 4.50 acetate buffer solution. The detection limit for both analytes is 5 × 10−8 M (S/N = 3:1). The present voltammetric method has been successfully used to determine trace p-aminobenzoic acid in procaine hydrochloride injection and procaine in plasma with a linear relationship of current to its concentration ranging from 1.0 × 10−6 to 5.0 × 10−5 M (correlation coefficient of 0.9981) with a low detection limit of 5.0 × 10−7 M (S/N = 3:1). This validated method is promising to the study of pharmacokinetics in Sprague–Dawley rat and rabbit plasma after an intravenous administration of procaine hydrochloride injection.

The evolution of second phases and its effect on tensile mechanical property in artificial ageing and RRA process of super-high strength aluminum alloy is investigated.The result of tensile test shows that the samples of Al-Zn-Mg-Cu-Ag alloy aged at lower temperature(100°C) not only have higher tensile strength up to 753Mpa but also relatively higher tensile elongation above 9% than normal temperature(120°C) in artificial ageing. The sample of Al-Zn-Mg-Cu alloy has the highest tension strength upto 788Mpa when aged at 100°C for 48 hours in single step of artificial ageing. Further more in RRA process samples of Al-Zn-Mg-Cu alloy preaged at 100°C for 24 hours retrogressed at 200°C for 7min and reaged at 100°Cfor 24 hours present the best tensile strength of 795Mpa than others. The tensile strength of Al-Zn-Mg-Cu alloy after RRA treated decreases with prolonging of retrogression time and reageing time starting from 7mins and 24 houres respectively. SEM observation shows that crack of the samples in tensile test is created at large particles in the fracture while there are more particles of undissolved phase in Al-Zn-Mg-Cu alloy containing Ag. TEM observation shows that the dominant strengthening particle corresponding to the peak strength of Al-Zn-Mg-Cu alloy containing Ag when aged at 120°C for 8 hours is η’ phase while dominant strengthening particle is G.P zone when aged at 100°C for 80 hours. However, η’ phase as the dominant strengthening particles corresponds to the peak strength of Al-Zn-Mg-Cu alloy without content of Ag when aged at 100°C for 48hours. TEM observation also shows that G.P zone as strengthening particle is dominant in the samples of Al-Zn-Mg-Cu alloy reaged at 100°C for 24 hours, and strengthening particles is coarsened when the sample is retrogressed at 200°C and reaged for a longer time. It is suggested that whether at the presence of coarse particles of undissolved phases or when G.P zone and η’ particle grow up in the retrogression ,sample needs deformable G.P zone instead of undeformable η’ in subsequent artificial ageing and reageing as dominant strengthening particle, in order to present a larger freedom spacing for dislocation to slip and let the sample not to behave too brittle to display high resistance to imposed plastic deformation or high tensile strength.

A novel coupling mechanism-based imaging approach to scanning electrochemical microscopy (SECM) was used to image the distribution of electric field at the end channel of a poly(dimethylsiloxane) (PDMS) capillary electrophoresis (CE) microchip in the absence of redox species. The coupling imaging mechanism was systematically investigated and qualitatively illustrated. It was proved that the distribution of solution potentials within the scanning plane caused a different reduction rate of water at the tip electrode, which led to the variation in tip current. Within the scanning plane, the solution potentials measured in the central area of the microchannel were usually higher than those measured outside. The SECM images showed a strong dependence on tip potential, tip-to-channel distance, and separation potential. According to the Tafel equation, SECM images were converted to parameters that directly showed the distribution of solution potential. Change in the solution potential along the central axial line of the microchannel was also continuously sensed by allowing the tip to approach the microchannel in the presence of high voltage. Using dopamine as a model compound, the effect of solution potential on electrochemical detection was estimated by detecting separation parameters.

This paper discusses the application of a direct integral area method and a multi-Gaussian curve fitting method to the interpretation of visible Raman spectra. A data analysis study was performed on three amorphous carbon films prepared by magnetron sputtering. Application of XPS, AES and the direct integration of the areas under the curves generated by visible Raman spectra, gave results that represented the diamondlike qualities of three amorphous carbon films in a similar manner, but the representation of data-trends using the multi-Gaussian curve fitting method was irregular. More specifically, we discovered that both the number of Gaussian curves applied, and the analytic regions chosen for analyzing the spectra affected the interpretation of the data obtained; our results indicate that the multi-Gaussian curve fitting method may give rise to inconsistent results when applied to the analysis of the visible Raman spectra of diamond-like (amorphous) carbon films. [doi:10.2320/matertrans.M2010234]

Museums have become an important venue for scientists and the public to have conversations about nanotechnology, reports Ai Lin Chun.