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In situ consolidation of the thermoplastic composites can be realized through laser-assisted automated fiber placement technology, and the properties of the composites are significantly affected by the crystallinity. Understanding the complicated crystallization process is very important for controlling the performance of the composites manufactured by automated fiber placement. In this work, the crystallization mechanism of carbon fiber/polyphenylene sulfide composites during the automated fiber placement process and its effect on the mechanical properties were investigated. Crystallization kinetics analysis indicated that the crystallization window of the carbon fiber/polyphenylene sulfide composites was 87–270°C. Furthermore, for carbon fiber/polyphenylene sulfide composites manufactured by automated fiber placement, the crystallinity was influenced by the parameters including laser temperature, placement speed and tool temperature, in which the tool temperature was the main factor. Increasing the tool temperature was an effective method to achieve high crystallinity. Meanwhile, when the tool temperature was in the range of the crystallization window, the composites could experience isothermal crystallization, which could further improve the crystallinity. With the increase of the tool temperature, the flexural strength and interlaminar shear strength were improved due to the enhanced self-adhesion of the matrix, while the Mode І fracture toughness was decreased because of the reduction of the matrix ductility. The combination of the kinetic method and experimental study was conducive to a better understanding of the crystallization mechanism and optimization of the processing conditions.

Osteoporosis (OP) is a systemic metabolic disorder characterized by a reduction in bone tissue volume. LncRNAs have been reported to act as regulators of several human diseases. Specifically, lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) is involved in proliferation, differentiation and apoptosis in osteoclasts and bone marrow mesenchymal stem cells and regulates the occurrence and development of OP. However, the relationship between NEAT1 and osteoblast autophagy and its mechanism are still unclear. Western blotting of LC3 and P62 was used to evaluate the effect of fluid shear stress (FSS) on autophagy in MC3T3-E1 osteoblasts. Total transcriptome sequencing and bioinformatics analyses were performed on osteoblasts loaded with and without FSS. qPCR was performed to examine the expression of NEAT1 in OP bone tissues and osteoblasts. The RNA-FISH was performed to study the localization of lncRNA NEAT1 and miR-466f-3p in MC3T3-E1 osteoblasts. In vitro, western blotting, transmission electron microscopy (TEM), immunofluorescence (IF) staining and qPCR were performed to verify the biological functions of NEAT1, miR-466f-3p and HK2. Subsequently, we conducted bioinformatics analysis and dual luciferase reporter assays to identify the relationships among NEAT1, miR-466f-3p and HK2. Additionally, rescue assays were conducted on osteoblasts to clarify the regulatory network of the NEAT1/miR-466f-3p/HK2 signalling pathway. In vivo, the OVX mouse model was used to investigate the effects of si-NEAT1 on autophagy in OP mice. The distal femur and serum were collected for further micro-CT analysis, blood biochemistry, and haematoxylin-eosin and Alizarin red staining (ARS). Immunohistochemistry (IHC) was performed to assess the protein expression of LC3 and HK2. NEAT1 expression was upregulated in OP tissues and osteoblast lines exposed to FSS. Knockdown of NEAT1 inhibited autophagy in vitro and in vivo. Further studies demonstrated that NEAT1 positively regulated HK2 expression via its competing endogenous RNA effects on miR-466f-3p. Moreover, we found the NEAT1/miR-466f-3p/HK2 axis regulated autophagy in osteoblasts. Knocking down NEAT1 inhibited autophagy in osteoblasts via the miR-466f-3p/HK2 signalling pathway, which may provide new ideas for novel molecular therapeutic targets of postmenopausal OP. KEY MESSAGES: • Fluid shear stress (FSS) can promote autophagy of osteoblast and performed transcriptome sequencing. • NEAT1 is overexpressed in osteoporosis and could regulate osteoblast cells autophagy. • Knockdown of lncRNA NEAT1 inhibited osteoblast cells autophagy by sponging miRNA-466f-3p and targeting HK2 in osteoporosis.

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Oncogenic extrachromosomal DNA elements (ecDNA) play an important role in tumor evolution, but our understanding of ecDNA biology is limited. We determined the distribution of single-cell ecDNA copy number across patient tissues and cell line models and observed how cell-to-cell ecDNA frequency varies greatly. The exceptional intratumoral heterogeneity of ecDNA suggested ecDNA-specific replication and propagation mechanisms. To evaluate the transfer of ecDNA genetic material from parental to offspring cells during mitosis, we established the CRISPR-based ecTag method. ecTag leverages ecDNA-specific breakpoint sequences to tag ecDNA with fluorescent markers in living cells. Applying ecTag during mitosis revealed disjointed ecDNA inheritance patterns, enabling rapid ecDNA accumulation in individual cells. After mitosis, ecDNAs clustered into ecDNA hubs, and ecDNA hubs colocalized with RNA polymerase II, promoting transcription of cargo oncogenes. Our observations provide direct evidence for uneven segregation of ecDNA and shed new light on mechanisms through which ecDNAs contribute to oncogenesis.Significance:ecDNAs are vehicles for oncogene amplification. The circular nature of ecDNA affords unique properties, such as mobility and ecDNA-specific replication and segregation behavior. We uncovered fundamental ecDNA properties by tracking ecDNAs in live cells, highlighting uneven and random segregation and ecDNA hubs that drive cargo gene transcription.See related commentary by Henssen, p. 293.This article is highlighted in the In This Issue feature, p. 275

Carbon fiber (CF) reinforced thermoplastic composites have great potential in the aerospace industry. However, defects and delamination restrict the application of the composites. This study investigated the effect of cooling rate on the crystallization and inter-laminar fracture toughness of CF reinforced polyphenylene sulfide (CF/PPS) composites. Differential scanning calorimetry (DSC) results showed that the crystallinity of the composites decreased from 49.6% to 27.1% when the cooling rate increased from 2°C/min to 1000°C/min. Meanwhile, mode I and mode II fracture toughness, as measured by the double cantilever beam (DCB) and end-notched flexure (ENF) tests, increased by 486% and 52%, respectively. The fracture morphology of the composites after DCB tests showed that when the cooling rate was 2, 30, and 300°C/min, the crack propagation occurred inside the resin, which was a typical cohesive failure. Moreover, when the cooling rate was 1000°C/min, the crack propagation belonged to the combination of cohesive and adhesive failure, indicating that a high cooling rate was conducive to improving the fracture toughness. It also turned out that the contribution of the matrix deformation dominated the fracture toughness.

Next-generation sequencing (NGS) has developed rapidly in the last decade and is emerging as a promising diagnostic tool for periprosthetic joint infection (PJI). However, its diagnostic value for PJI is still uncertain. This systematic review aimed to explore the diagnostic value of NGS for PJI and verify its accuracy for culture-negative PJI patients. We conducted this systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Medline, Embase, and Cochrane Library were searched to identify diagnostic technique studies evaluating the accuracy of NGS in the diagnosis of PJI. The diagnostic sensitivity, specificity, and positive and negative predictive values were estimated for each article. The detection rate of NGS for culture-negative PJI patients or PJI patients with antibiotic administration history was also calculated. Of the 87 identified citations, nine studies met the inclusion criteria. The diagnostic sensitivities and specificities of NGS ranged from 63% to 96% and 73% to 100%, respectively. The positive and negative predictive values ranged from 71% to 100% and 74% to 95%, respectively. The detection rate of NGS for culture-negative PJI patients in six studies was higher than 50% (range from 82% to 100%), while in three studies it was lower than 50% (range from 9% to 31%). Also, the detection rate of NGS for PJIs with antibiotic administration history ranged from 74.05% to 92.31%. In conclusion, this systematic review suggests that NGS may have the potential to be a new tool for the diagnosis of PJI and should be considered to be added to the portfolio of diagnostic procedures. Furthermore, NGS showed a favorable diagnostic accuracy for culture-negative PJI patients or PJI patients with antibiotic administration history. However, due to the small sample sizes of studies and substantial heterogeneity among the included studies, more research is needed to confirm or disprove these findings.

In situ consolidation of thermoplastic composites can be realized through laser-assisted automated fiber placement (AFP) technology, and the properties of composites were significant affected by the process parameters. In this work, the effects of process parameters on the properties of continuous carbon fiber–reinforced polyphenylene sulfide (CF/PPS) composites manufactured by laser-assisted AFP were investigated. Four-plies CF/PPS prepreg was laid under the combination of different process parameters and the morphology, void content, crystallinity, and inter-laminar shear strength (ILSS) of the composites were characterized. It turned out that the resin distribution on the surface of the composites could be significantly improved by increasing the laser temperature and compaction pressure. The highest crystallinity of the composites reached 46% at tool temperature of 120°C while the value was only 18% when the tool temperature was 40°C. Meanwhile, with the increasing compaction force ranging of 500–2000 N, the void content of the composites decreased obviously. The ILSS was evaluated through double notch tensile shear test. The results indicated that the mechanical properties of the composites were dominated by void content rather than crystallinity.

In in situ consolidation of thermoplastic composites by laser-assisted automated fibre placement (AFP), high laser irradiation temperature can improve the fluidity of the resin matrix, which usually enhances the performances of composites. However, it leads to a tendency for thermal degradation as the resin matrix of the composites is exposed to high temperatures for a long time. The thermal degradation behaviours of continuous carbon fibre (CF)-reinforced polyphenylene sulfide (PPS) composites during in situ consolidation by laser-assisted AFP were studied. A thermogravimetric analysis shows that the thermal degradation of CF/PPS composites is quite complex, with multi-step reactions. The thermal degradation of the composites was further analysed via kinetic methods. A thermal degradation kinetic model of the resin matrix was obtained and verified. According to the kinetic model, the thermal degradation of the composites under different placement conditions was predicted. The results were confirmed by Fourier-transform infrared spectroscopy and scanning electron microscopy. With the combination of the kinetic model, AFP in situ consolidation, and characterisation techniques, processing parameters such as laser irradiation temperature and placement speed can be adjusted and optimised.

Mangiferin is a xanthone glucoside extracted from multiple plants, which has been shown to inhibit bone resorption and alleviate osteoporosis. However, the effect of purified Mangiferin on osteoporosis and its specific mechanisms is unknown. This study aimed to explore whether Mangiferin can promote osteogenic differentiation and alleviate osteoporosis in ovariectomized (OVX) mice and explore the potential mechanisms. Different concentrations and durations of Mangiferin were applied to MC3T3-E1 cells. The optimal concentration and duration of Mangiferin were determined by evaluating the cell viability

The inter-ply sliding behavior is one of the important factors affecting the quality of carbon fiber composite products. In this paper, the inter-ply sliding behavior of the unidirectional prepreg was investigated for the preforming process. The inter-ply sliding resistance of prepreg under different conditions was measured by the homemade measuring device and the lubricating effect of inter-ply resin was identified by the micromorphology. The effect of fiber orientation was quantified by the combined roughness. With the increase of sliding distance, the inter-ply sliding resistance initially increased significantly, and finally maintained a constant value. A phenomenological model of the inter-ply sliding resistance was developed to explain the effects of pressure, velocity, and fiber orientation. This model can accurately describe the inter-ply sliding behavior of prepreg, which can be used for numerical simulation and the optimization of preforming process.

Oncogenic extrachromosomal DNA elements (ecDNA) play an important role in tumor evolution, but our understanding of ecDNA biology is limited. We determined the distribution of single-cell ecDNA copy number across patient tissues and cell line models and observed how cell-to-cell ecDNA frequency varies greatly. The exceptional intratumoral heterogeneity of ecDNA suggested ecDNA-specific replication and propagation mechanisms. To evaluate the transfer of ecDNA genetic material from parental to offspring cells during mitosis, we established the CRISPR-based ecTag method. ecTag leverages ecDNA-specific breakpoint sequences to tag ecDNA with fluorescent markers in living cells. Applying ecTag during mitosis revealed disjointed ecDNA inheritance patterns, enabling rapid ecDNA accumulation in individual cells. After mitosis, ecDNAs clustered into ecDNA hubs, and ecDNA hubs colocalized with RNA polymerase II, promoting transcription of cargo oncogenes. Our observations provide direct evidence for uneven segregation of ecDNA and shed new light on mechanisms through which ecDNAs contribute to oncogenesis. Significance: ecDNAs are vehicles for oncogene amplification. The circular nature of ecDNA affords unique properties, such as mobility and ecDNA-specific replication and segregation behavior. We uncovered fundamental ecDNA properties by tracking ecDNAs in live cells, highlighting uneven and random segregation and ecDNA hubs that drive cargo gene transcription. See related commentary by Henssen, p. 293. This article is highlighted in the In This Issue feature, p. 275

Integration host factor (IHF) is a nucleoid-associated protein involved in DNA packaging, integration of viral DNA and recombination. IHF binds with nanomolar affinity to duplex DNA containing a 13 bp consensus sequence, inducing a bend of ~160° upon binding. We determined that IHF binds to DNA Four-way or Holliday junctions (HJ) with high affinity regardless of the presence of the consensus sequence, signifying a structure-based mechanism of recognition. Junctions, important intermediates in DNA repair and homologous recombination, are dynamic and can adopt either an open or stacked conformation, where the open conformation facilitates branch migration and strand exchange. Using ensemble and single molecule Förster resonance energy transfer (FRET) methods, we investigated IHF-induced changes in the population distribution of junction conformations and determined that IHF binding shifts the population to the open conformation. Further analysis of smFRET dynamics revealed that even in the presence of protein, the junctions remain dynamic as fast transitions are observed for the protein-bound open state. Protein binding alters junction conformational dynamics, as cross correlation analyses reveal the protein slows the transition rate at 1 mM Mg2+ but accelerates the transition rate at 10 mM Mg2+. Stopped flow kinetic experiments provide evidence for two binding steps, a rapid, initial binding step followed by a slower step potentially associated with a conformational change. These measurements also confirm that the protein remains bound to the junction during the conformer transitions and further suggest that the protein forms a partially dissociated state that allows junction arms to be dynamic. These findings, which demonstrate that IHF binds HJs with high affinity and stabilizes junctions in the open conformation, suggest that IHF may play multiple roles in the processes of integration and recombination in addition to stabilizing bacterial biofilms.

Articular cartilage consists of an extracellular matrix including many proteins as well as embedded chondrocytes. Articular cartilage formation and function are influenced by mechanical forces. Hind limb unloading or simulated microgravity causes articular cartilage loss, suggesting the importance of the healthy mechanical environment in articular cartilage homeostasis and implying a significant role of appropriate mechanical stimulation in articular cartilage degeneration. Mechanosensitive ion channels participate in regulating the metabolism of articular chondrocytes, including matrix protein production and extracellular matrix synthesis. Mechanical stimuli, including fluid shear stress, stretch, compression and cell swelling and decreased mechanical conditions (such as simulated microgravity) can alter the membrane potential and regulate the metabolism of articular chondrocytes via transmembrane ion channel-induced ionic fluxes. This process includes Ca2+ influx and the resulting mobilization of Ca2+ that is due to massive released Ca2+ from stores, intracellular cation efflux and extracellular cation influx. This review brings together published information on mechanosensitive ion channels, such as stretch-activated channels (SACs), voltage-gated Ca2+ channels (VGCCs), large conductance Ca2+-activated K+ channels (BKCa channels), Ca2+-activated K+ channels (SKCa channels), voltage-activated H+ channels (VAHCs), acid sensing ion channels (ASICs), transient receptor potential (TRP) family channels, and piezo1/2 channels. Data based on epithelial sodium channels (ENaCs), purinergic receptors and N-methyl-d-aspartate (NMDA) receptors are also included. These channels mediate mechanoelectrical physiological processes essential for converting physical force signals into biological signals. The primary channel-mediated effects and signaling pathways regulated by these mechanosensitive ion channels can influence the progression of osteoarthritis during the mechanosensory and mechanoadaptive process of articular chondrocytes.

Fluid shear stress (FSS) plays a critical role in osteoblast proliferation. However, the role of miRNA in osteoblast proliferation induced by FSS and the possible molecular mechanisms remain to be defined. The aim of the present study was to investigate whether miR-140-5p regulates osteoblast proliferation under FSS and its molecular mechanism.miR-140-5p expression was measured by qRT-PCR. Western blot was used to measure the expressions of P-ERK1/2, ERK1/2, P-ERK5 and ERK5. The levels of VEGFA, PCNA, CDK4 and Cyclin D1 were identified through qRT-PCR and western blot, respectively. Cell proliferation was detected by CCK-8 assay and EdU labeling assay. Dual-luciferase reporter assay was used to validate the target of miR-140-5p.miR-140-5p was significantly down-regulated when MC3T3-E1 cells were exposed to FSS. We then confirmed that up-regulation of miR-140-5p inhibited and down-regulation of miR-140-5p promoted osteoblast proliferation. In addition, FSS promotes osteoblast proliferation via down-regulating miR-140-5p. Luciferase reporter assay demonstrated that VEGFA is a direct target of miR-140-5p. Furthermore, transfection of mimic-140-5p inhibited the up-regulation of VEGFA protein level induced by FSS, suggesting that FSS regulates VEGFA protein expression via miR-140-5p. Further investigations demonstrated that VEGFA could promote osteoblast proliferation. Lastly, we demonstrated that miR-140-5p regulates osteoblast proliferation and ERK5 activation through VEGFA.Our study demonstrates that FSS-induced the down-regulation of miR-140-5p promotes osteoblast proliferation through activing VEGFA/ERK5 signaling pathway. These findings may provide a novel mechanism of FSS-induced osteoblast proliferation and offer a new avenue to further investigate osteogenesis induced by mechanical loading.

Background Fibrinogen (FIB) has been used to differentiate periprosthetic joint infection (PJI) from aseptic loosening. The purpose of this study was to evaluate the diagnostic value of FIB in predicting postoperative reinfection in patients with debridement, antibiotics and implant retention (DAIR). Methods We retrospectively analyzed the patients who were admitted to DAIR from January 2013 to August 2019 for consideration of PJI readmission. Subgroups were divided into subgroups based on whether there was reinfection after DAIR treatment, and the diagnostic value of serum fibrinogen, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) before DAIR treatment was analyzed by receiver operating Characteristic curve (ROC). To evaluate the diagnostic value of FIB in predicting postoperative reinfection in DAIR patients. Results FIB expression was different in acute PJI patients and chronic PJI patients treated with DAIR (4.03 VS 3.08; P

Oncogenic extrachromosomal DNA elements (ecDNAs) promote intratumoral heterogeneity, creating a barrier for successful cancer treatments. The underlying mechanisms are poorly understood and studies are hampered in part by a lack of adequate tools enabling studies of ecDNA behavior. Here, we show that single-cell ecDNA copy numbers greatly vary between tumor cells, both in vitro and in patient glioblastoma specimens, suggesting uneven ecDNA segregation during mitosis. We established a CRISPR-based approach which leverages unique ecDNA breakpoint sequences to tag ecDNA with fluorescent markers in living cells. Applying this method during mitosis revealed disjointed ecDNA inheritance patterns, providing an explanation for rapid ecDNA accumulation in cancer. Post-mitosis, ecDNAs tended to cluster and clustered ecDNAs colocalized with RNA polymerase II, promoting transcription of cargo oncogenes. Our observations provide direct evidence for uneven segregation of ecDNA and sheds new light on mechanisms through which ecDNAs contribute to oncogenesis.

The precise association between palm oil consumption and lipid-related cardiovascular disease risk remains unclear. A systematic review was thus performed to assess whether palm oil consumption has a negative effect on plasma lipid-related cardiovascular disease marker levels.In June 2018, the electronic bibliographic databases PubMed, EMBASE (Ovid), the Cochrane Library (Ovid) and the Chinese National Knowledge Infrastructure were searched and a total of 11 eligible dietary intervention articles involving 961 volunteers were selected. Both random and fixed effect models were used to calculate pooled weighted mean differences (WMD).A total of 11 articles involving 547 participants met the inclusion criteria. The pooled analysis revealed that palm oil increased the concentration of high-density lipoprotein cholesterol (WMD: 0.15 mmol/L; p0.00001). Palm oil consumption had no significant effects on blood total cholesterol (WMD: -0.01 mmol/L; p=0.82) and LDL-c (WMD: -0.05mmol/L; p=0.10) and triglyceride concentrations (WMD: 0.00 mmol/L; p=0.96), relative to the effects of unsaturated fatty acid consumption. Subgroup analyses revealed that palm oil has a beneficial effect on High-density lipoprotein cholesterol levels when more than 30% of total dietary energy was constituted by fat.This review revealed that palm oil does not induce increases in cardiovascular disease risk risk-related biomarkers relative to unsaturated fatty acids. Furthermore, larger-scale samples of human dietary intervention trials are required to increase the accuracy of meta-analyses.

Poly(3,4-ethylenedioxythiophene)/lignosulfonate acid (PEDOT/LS) submicron particles are doped into a 3,4-ethylenedioxythiophene (EDOT)/water mixture as a solid stabilizer to form a Pickering emulsion. The conductivity of the new PEDOT/LS complexes prepared by Pickering emulsion polymerization (PEDOT/LS-PEP) is improved by 2 orders of magnitude. The structure and properties of PEDOT/LS-PEP are investigated by UV, FTIR, XRD, XPS, DLS, optical microscope, four point probe meter, and surface resistance tester. The results show that the average particle size increases from 550 nm to 2.4 μm, and the PEDOT content in PEDOT/LS-PEP is 3.5 times that in the original PEDOT/LS submicron particles, while the structure of PEDOT/LS-PEP remains amorphous. Due to the enhancement in conductivity, the coating film made by PEDOT/LS-PEP decreases the surface resistance of glass from 1012 to 106 Ω sq–1. These new PEDOT/LS-PEP complexes meet the requirement of industrial antistatic materials well.

Lignosulfonic acid (LS) has been applied both as dispersant and dopant for chemical polymerization of 3,4-ethylenedioxythiophene (EDOT). EDOT is successfully polymerized in LS aqueous solutions, resulting in a water-dispersive poly(3,4-ethylenedioxythiophene) (PEDOT) conductive nanoparticle (PEDOT:LS). The structure, intermolecular interaction, and performance of the PEDOT:LS were investigated by ultraviolet-visible-Near-infrared spectrophotometry, Fourier transform infrared spectroscopy, thermogravimetric analysis, dynamic light scattering, transmission electron microscopy, X-ray photoelectron spectroscopy, and surface resistivity tester. Results were interpreted in a way that PEDOT:LS is a polyelectrolyte complex, in which the highly hydrophobic PEDOT is in the inner part of the particle and the LS-rich layer with high hydrophilicity is on its surface. During oxidizing reaction of EDOT to PEDOT in LS, the water-insoluble PEDOT product is adsorbed on the surface of water-soluble LS by electrostatic attraction and forms PEDOT:LS polyelectrolyte complexes. In this process, excess LS is needed to be adsorbed on the surface of PEDOT:LS complexes. The process is driven by π-π interaction to increase the water solubility and contributes to a continuous polymerization. The PEDOT:LS as coating has a good conductivity, transparency, humidity resistance, water resistance, and thermal stability and can be used as high-performance antistatic agents.

This chapter provides an overview of Chinese intended mathematics curricula and assessment through an analysis of four policy documents of mathematics education at national level.

This chapter provides a background to the study including a description of the mathematics achievement gap, the purpose of the research, key terms used, and research questions, and the final section of the chapter offers a summary of the book.

This chapter reports a case study on how the intended mathematics curriculum and assessment have been implemented in an Australian primary school, where there were considerable Chinese background students.

The description of the development and implementation of the research methodology is presented in this chapter, which addresses the value of case studies in terms of their contribution to the refinement and modification of extant theory, and ultimately to the creation of new theory.

This chapter reports a case study on the intended mathematics curriculum and assessment have been implemented in another Australian primary school, where the majority students were from European background.

This chapter provides a review of literature on the topic of comparative studies of mathematics achievement and summaries the key factors suggested by other studies contributing to achievement gap between the East and the West in generally, especially between China and Australia.

This chapter reports a case study on how Chinese intended mathematics curriculum and assessment have been implemented in a Guangzhou primary school.

This Chapter discusses the main findings of the study and how they related to the mathematics achievement gap. It also deliberates the implications of the findings to mathematics curriculum and assessment reform both in Australia and in China. In this concluding chapter, the main findings and the limitations of the study are discussed, followed by implications of the study for research, curricula, instruction, and assessment.

This chapter presents an overview of Australian intended mathematics curriculum and assessment through an analysis of major mathematics education policy documents at both national and state levels.

This chapter provides a comparison of intended curriculum and assessment between Austria and China, and it also discusses the rationale to understand these differences and similarities.

International comparative studies and cross-cultural studies of mathematics achievement indicate that Chinese students (whether living in or outside China) consistently outperform their Western counterparts. This study shows that the gap between Chinese-Australian and other Australian students is best explained by differences in motivation to achieve, attributing success to effort, the influence of parental help and the use of extra mathematics curricula. The argument explored is, in order to promote students’ mathematics achievement, we must improve the pedagogical knowledge of classroom teachers of mathematics, as well as to encourage parents’ involvement in the mathematics education of their children and to promote students’ motivation to learn mathematics.

BACKGROUND: The HOMO–LUMO energy level width of conjugated polymers can be manipulated by controlling the conjugation length of the polymeric materials in order to adjust their properties in terms of emission of different colors and realize polychromatic displays. In the work reported in this paper azobisisobutyronitrile (AIBN) was used to control the conjugation length of poly[2-methoxy-5-(2′-ethylhexyloxy)-co-(1,4-phenylene vinylene)] (MEH-PPV) by free radical addition. In this way a series of MEH-PPV with various conjugation lengths was obtained. RESULTS: Characterization of MEH-PPV using 1H NMR and Fourier transform infrared spectroscopy demonstrated that the cyano groups of AIBN hydrolyzed into carboxyls. The carboxyl free radicals attacked the conjugated double bonds of MEH-PPV, resulting in a decrease of trans-vinylenes and in an increase of cis-vinylenes as well as tert-methyls on the backbone. Changing the conjugated structure of the polymer caused the peaks of UV and fluorescence spectra to shift to the blue. CONCLUSION: The resulting MEH-PPV derivatives can emit orange-red, green and blue light. It is expected that they could be used to prepare PPV-based materials that could modulate white light emission, by simply blending the PPV derivatives emitting different colors. Copyright © 2008 Society of Chemical Industry

The hybrid microspheres of ZnO/PS with different core–shell structures were prepared in miniemulsion polymerization. 3-(trimethoxysilyl)propyl methacrylate (MPS) was used as a functional comonomer to enhance the surface polarity of ZnO nanoparticles and to prevent water from quenching the luminescent properties of ZnO. The morphology of hybrid particles was examined with a transmission electron microscope. The luminescence spectra were measured using a Shimadzu RF-5301 PC spectrofluorimeter (Xe source) at room temperature. The crystallization structure of samples was characterized with a Rigaku wide-angle X-ray diffractometer. The chemical composition and structure of the ZnO colloids, MPS-modified ZnO colloids, and ZnO/PS hybrid microspheres were analyzed with IR.

Poly(vinyl alcohol) (PVA) hydrogels were prepared in aqueous solutions at different concentrations using glutaraldehyde (GA) as cross-linker. The gel fraction, increase rate of gels, critical gel point, and swelling ratio were measured. Furthermore, the influences of intramolecular cyclization on the cross-linking processes and the structure of formed hydrogels were studied. The results show that the degree of intramolecular cyclization and the ratio of [−CHO]/[−OH] at critical gel point (rc) increase with the decrease of PVA concentration. The bulk gels do not form when PVA concentration is below 1.1 × 10-2 g/mL even at higher GA/PVA mixture ratio. In the concentration range of (2.20−12.3) × 10-2 g/mL, intramolecular cyclization fraction is basically not changed with gel fraction above the critical gel point. The way of gel growing is controlled by PVA concentration. In a certain range, the lower the PVA concentration is, the higher the increase rate of gels is. The equilibrium swelling ratio decreases w...

General equations for lattice contraction and surface stress of fcc nanocrystals are established based on the Laplace−Young equation and a consideration for the size-dependence of the solid−liquid interface energy. The predictions of our equations are in agreement with the experimental results on the measurement of lattice contraction and surface (interface) stress of nanoparticles and thin films and theoretical calculations.

(Chemical Equation) An electric-current-assisted method was used to mineralize dense hydrogels and create hydroxyapatite/hydrogel composites with unique hierarchical structures. The microstructure of the final material can be controlled by the mineralization technique and the chemistry of the organic matrix. A hydroxyapatite/hydrogel composite was obtained with a large inorganic content (∼60% of the weight of the organics). After being heated to 1050°C, the sintered inorganic phase has a very uniformly distributed porosity and its Brunauer-Emmett-Teller (BET) surface area is 0.68 m2/g. © 2009 American Chemical Society.

The hybrid microspheres with polystyrene core coated by titania nanoparticles were prepared by miniemulsion polymerization, and the as-prepared samples were characterized by SEM, XRD, TG-DTA, XPS, and SPS techniques. TiO2 nanoparticles experienced two processes of phase transition, i.e., amorphous to anatase and anatase to rutile at the calcining temperature range from 400 to 1000 degrees C. The phase transformation temperature of TiO2 hybrid microspheres from anatase to rutile was increased by about 300 degrees C due to the blocking function of calcined polymer remainder. SPS results present that the band-gap of hybrid microspheres is 3.2-3.4 eV, which is larger than that of pure TiO2. The maximum intensity of the SPS signal is about 3 times larger for the hybrid material as compared to the pure TiO2. In addition, the photocatalytic degradation rate of TiO2 hybrid microspheres was 15% faster than that of pure TiO2 in the experiment of the photocatalytic degradation of methyl orange.