Search

With the increasing usage of hydrogen energy, the requirements for hydrogen detection technology is increasingly crucial. In addition to bringing down the working temperature, further improvement in the response and broadening the detection range of hydrogen sensors in particular are still needed. TiO2 based sensors show great promise due to their stable physical and chemical properties as well as low cost and easy fabrication, but their detection range and low concentration response requires further improvement for practical applications. Here (002) oriented rutile TiO2 thin films are prepared by a hydrothermal method followed by annealing in either air, oxygen, vacuum or H2 and the hydrogen sensing performance are evaluated. Raman results show that TiO2 thin films annealed in vacuum and hydrogen have more oxygen vacancies, while those annealed in air and oxygen have a more stoichiometric surface. Annealing in an oxygen-rich atmosphere is shown to extend the detection range of the TiO2 sensors while annealing in anaerobic atmospheres increases their response. At high hydrogen concentrations surface adsorbed O2− is the dominant factor, while at low concentrations the Schottky barrier between Pt and TiO2 is key to achieving a high response. Here we show controlling the TiO2 surface properties is essential for optimizing hydrogen detection over specific concentration ranges. We demonstrate that adjusting the annealing conditions and ambient provides a simple method for tuning the performance of room temperature operating TiO2 based hydrogen sensors.

Camellia nitidissima is an endangered species whose flowers are bright yellow. In the past 50 years, habitat changes caused by climate and human activity have greatly reduced the extent and size of natural populations of C. nitidissima. Here, to provide a fundamental basis for this plant’s protection and utilization, the genetic diversity and genetic structure of C. nitidissima natural populations were studied using simple sequence repeats (SSR) markers. Based on a comparative analysis of multiple transcriptomes from different Camellia species, a group of consensus transcript sequences were obtained for marker development. We screened 237 predicted transcript loci, and identified 21 highly polymorphic SSR markers for population analysis. In total, 82 alleles were obtained to assess the genetic diversity of four natural populations in Guangxi Zhuang autonomous region, China. The results revealed that the mean observed heterozygosity (Ho) and expected heterozygosity (He) of the populations were 0.624 and 0.546, respectively, and the genetic diversity was mostly among populations. Further, we uncovered a significant positive correlation between the genetic distance and geographic distance of C. nitidissima populations. The high genetic diversity found in this study holds promise for the future conservation and restoration of C. nitidissima populations based on efforts from in situ and ex situ strategies implemented in a carefully monitored way.

Against the backdrop of a heavy carbon lock-in energy structure, China has made considerable progress in renewable energy (RE) development and become a world leader in this area within a decade. Al...

The great diversity and complexity of floral scent originate from specialized metabolic pathways partly due to the ever-evolving plant and pollinator interaction. However, the diversity of floral scent compositions in plant species remains to be elucidated. Genus Camellia contains a large number of species including several famous ornamental species, and species within the section Theopsis possess distinctive floral scent traits. In this study, we have collected 22 species from Theopsis and performed headspace- solid phase microextration coupled with gas chromatography mass spectrum (HS-SPME-GC–MS) analysis to investigate the scent compositions. In total, we identified 223 volatile compounds belonging to benzenoids, phenyl propanoids, terpenes, and other components. Remarkable interspecific variations in composition and quantity were revealed. We characterized the relationships of different types of volatile compounds by hierarchical clustering and principal component analysis, and showed that small amount of chemicals could affect the scent effects significantly. Moreover, we compared the volatile emission patterns between different floral organ types and developmental stages in Camellia buxifolia. We revealed that stamens emitted more volatiles than petals, and the emission reached the maximum at the stage of flower half opening. This work provides fundamental information for breeding Camellia cultivars with scent traits.

Photothermal therapy based on nanoparticles is a promising method for cancer treatment. However, there are still many limits in practical application. During photothermal therapy, improving therapeutic effect is contradictory to reducing overheating in healthy tissues. We should make the temperature distribution more uniform and reduce the damage of healthy tissue caused by overheating. In the present work, we develop a simple computational method to analyze the temperature distribution during photothermal therapy at three levels (nanoscale, micron scale, and millimeter scale), and investigate the effects of nanoparticle size, volume fraction, light intensity, and irradiation shape on temperature distribution. We find that it is difficult to achieve good therapeutic effect just by adjusting the volume fraction of nanoparticles and light intensity. To achieve good therapeutic effect, we propose a new irradiation shape, spot array light. This method can achieve a better temperature distribution by easily regulating the positions of spots for the tumor with a large aspect ratio or a small one. In addition, the method of irradiation with spot array light can better reduce the overheating at the bottom and top of the tumor than the full-coverage light or others such as ring light. This theoretical work presents a simple method to investigate the effects of irradiation shape on therapy and provides a far more controlled way to improve the efficacy of photothermal therapy.

Sublingual vein segmentation is an essential yet challenging task in computer-aided Traditional Chinese Medicine (TCM) tongue diagnosis. The most intricate part of sublingual vein segmentation is the strong diversity of sublingual vein images (e.g., various exposure of vein and complex background) and the natural connectivity of veins. To this end, we propose a novel and effective approach based on generative adversarial networks (GANs). Specifically, the framework comprises two modules: a segmentation generator network with multi-scale outputs and a scale-consistent discriminator. The former segmentation generator learns the overall structure of the segmentation, which reduces the training difficulties of stride 1 output by multi-scale outputs. The latter scale-consistent discriminator regularizes the segmentation maps from different output strides, which keeps the natural connectivity of veins and avoids generated noise. Additionally, we have constructed and publicized a well-annotated sublingual vein dataset (FDU-SV) which we believe will promote the significant development of this area. Extensive experimental results confirm that our method outperforms other representative segmentation models with a remarkable margin, achieving the state-of-the-art performance of 64.53% mIoU score. Code and dataset are available at https://github.com/echobear313/FDUVEIN.

Camellia japonica is a plant species with great ornamental and gardening values. A novel hybrid cultivar Chunjiang Hongxia (Camellia japonica cv. Chunjiang Hongxia, CH) possesses vivid red leaves from an early growth stage to a prolonged period and is, therefore, commercially valuable. The molecular mechanism underlying this red-leaf phenotype in C. japonica cv. CH is largely unknown. Here, we investigated the leaf coloration process, photosynthetic pigments contents, and different types of anthocyanin compounds in three growth stages of the hybrid cultivar CH and its parental cultivars. The gene co-expression network and differential expression analysis from the transcriptome data indicated that the changes of leaf color were strongly correlated to the anthocyanin metabolic processes in different leaf growth stages. Genes with expression patterns associated with leaf color changes were also discussed. Together, physiological and transcriptomic analyses uncovered the regulatory network of metabolism processes involved in the modulation of the ornamentally valuable red-leaf phenotype and provided the potential candidate genes for future molecular breeding of ornamental plants such as Camellia japonica.

Nanoholes obtained by droplet epitaxy has been intensively investigated as an important material platform for the fabrication of nanodevices due to their unique topology. However, the final fabricated nanoholes are very difficult to achieve a highly symmetric circular structure, and usually have two or four gaps in the sidewall of the holes. Here we have presented a developed model to inquire into the reasons for the formation of the gaps at the periphery of nanoholes and discuss how to improve the structural symmetry of the nanoholes. It is found that the anisotropic interface diffusion of As atoms decomposed by substrate can result in the formation of the gaps. In order to improve the symmetry of final nanostructures, we can minimize the interval time between deposition of Ga droplets and open operation of As flux, and set up a multistep growth procedure by changing the intensity of As flux or growth temperature.

Cell penetration by high aspect-ratio vertical nanostructures such as nanowires and nanopillars provides a powerful method for accessing the cell interior for delivery and sensing. However, there is a lack of studies on the understanding of the mechanism of cell membrane penetration and how design nanostructures to optimize the efficiency of penetration remains unclear. Here, we propose an analytical model to elucidate the mechanism of cells penetration by analyzing the free-energy change of cells adhered to the nanostructures surface. Furthermore, we provide a simple method to evaluate the crossover radius or density for cell membrane penetration. By introducing a dimensionless parameter, i.e., adhesion area factor, we investigated the effects of the radius and distribution densities of nanostructures on cell membrane penetration which is determined by the competition between adhesion energy and deformation energy. Besides, a diagram of the distribution of cell penetration and no penetration is obtained. From the cell penetration diagram, one can determine easily and intuitively the relations of cell penetration state with the radius and distribution densities of nanostructures. Our theoretical results seem to show broad agreement with experimental observations, which implies that these studies would provide useful guidance to the design of nanopatterned surfaces for biomedical applications.

Two sodium/potassium tetradentate aminobisphenolate ion-paired complexes were synthesized and structurally characterized. These ion-paired complexes are efficient catalysts for the ring-opening polymerization of rac-lactide (rac-LA) in the presence of 5 equivalents BnOH as an initiator and the side reaction of epimerization can be suppressed well at low temperatures. The polymerizations are controllable, affording polylactides with desirable molecular weights and narrow molecular weight distributions; the highest molecular weight can reach 50.1 kg mol-1 in this system, and a best isoselectivity of Pm =0.82 was achieved. Such polymerizations have rarely been reported for isoselective sodium/potassium complexes without crown ether as an auxiliary ligand. The solid structures suggest that BnOH can be activated by an interaction with the anion of sodium/potassium complex via a hydrogen bond and that the monomer is activated by coordination to sodium/potassium ion.

Nowadays, driver drowsiness and driver distraction is considered as a major risk for fatal road accidents around the world. As a result, driver monitoring identifying is emerging as an essential function of automotive safety systems. Its basic features include head pose, gaze direction, yawning and eye state analysis. However, existing work has investigated algorithms to detect these tasks separately and was usually conducted under laboratory environments. To address this problem, we propose a multi-task learning CNN framework which simultaneously solve these tasks. The network is implemented by sharing common features and parameters of highly related tasks. Moreover, we propose Dual-Loss Block to decompose the pose estimation task into pose classification and coarse-to-fine regression and Objectcentric Aware Block to reduce orientation estimation errors. Thus, with such novel designs, our model not only achieves SOA results but also reduces the complexity of integrating into automotive safety systems. It runs at 10 fps on vehicle embedded systems which marks a momentous step for this field. More importantly, to facilitate other researchers, we publish our dataset FDUDrivers which contains 20000 images of 100 different drivers and covers various real driving environments. FDUDrivers might be the first comprehensive dataset regarding driver attention monitoring.

Extremely thin nanowires (NWs) would bend during the heteroepitaxial growth process. This phenomenon can increase the emission intensity due to the strain fields within bent NWs. Although the growth mechanism of NW heterostructures has been widely studied in theory, the theoretical studies are centered on growth on the surface of straight NWs, and the bending mechanism on extremely thin NWs has not been clearly explored. In this contribution, we have established an analytical thermodynamic theory to study the mechanism of bending induced by heteroepitaxial growth on the surface of thin NWs. It is found that the balance between surface energy and elastic strain energy plays a crucial role in the determination of the bending of NWs. The strain relaxation energy induces bending of NWs with small radii and high deposited amounts, while the size-dependent surface energy becomes more significant and restrains the bending of NWs with large radii and low deposited amounts. The established theoretical model not only explained the bending mechanism of NWs but also provided useful information to design the epitaxial growth on the surface with a nanoscale curvature.

The bending of nanostructures (NSs), such as nanopillars and nanowires, caused by cell adhesion is an interesting phenomenon and is important for the measurements of cellular forces, understanding the biological behavior of cells, and disease diagnosis. However, which factors are related to the bending of NSs and how the factors affect bending displacement are still not well understood. Here, we establish an analytic thermodynamic theory to study the bending mechanism of NSs caused by cellular force during the cell adhesion process, and analyze the factors affecting bending displacement. It is found that the bending of NSs is determined by the competition between the stretching energy of the membrane and the strain energy of the NSs. The bending displacement can be evaluated based on our model.

Over the past decade, global energy generation via clean resources has grown considerably. An energy dependent region, Northeast Asia (NEA), in this regard, has made significant progress in clean energy development. However, a region-wide energy cooperation is still far from being realized due, in large part, to a lack of viable framework which helps coordinate, among others, infrastructure development, institution build-up, market connectivity and regulation, and financing. In this paper, through an examination of the potential role of an energy grid interconnection, we aim to explore the causal links between clean energy development in NEA and the emergence of a regional energy cooperation framework. We observe that the energy complementarities and complexities in NEA both facilitate and require the establishment of a regional energy grid, which would have far-reaching economic and political implications. Economically, grid development may encourage energy-related investment, innovation, efficiency and environmental protection. Geopolitically, regional grid networking may contribute to confidence building, institutionalization and de-securitization. Thus, we argue, as a process of energy socialization, the formation of a comprehensive and institutionalized cooperation framework in NEA would lead to broad implications for regional development, security and community build up.

Gibberellin 20‐oxidase (GA20ox) is a multifunctional enzyme that is involved in the regulation of GA biosynthesis and the control of plant growth. We identified and characterized a GA20ox gene (CrGA20ox1) in Camellia reticulata ‘Hentiangao’; subsequently, expression levels of CrGA20ox1 in four phenotypically different camellias were analysed using fluorescent quantitative real‐time PCR (qRT‐PCR). The results demonstrated that the CrGA20ox1 gene was expressed in all four camellias at various levels, indicating that the gene's expression intensity was positively associated with camellia height. In addition, phenotypic comparison among transgenic tobacco plants saw a nearly 3.6‐fold increase in height of sense CrGA20ox1 lines as contrasted with wild‐type tobacco. Interestingly and contrarily, the height of the transgenic plants expressing antisense CrGA20ox1 copies decreased by only around 0.5‐fold of the controls’ height. Endogenous hormone measurements illustrated that bioactive GA₄ predominantly increased in sense transgenic plants, whereas an obvious drop was observed in the antisense lines. Hence, overexpression of the CrGA20ox1 gene could accelerate vegetative growth; however, silent expression of the CrGA20ox1 gene impelled plants towards dwarfism.

Camellia grijsii is an ornamental shrub with a floral aroma, which is widely cultivated and used for landscaping in China. To obtain the genetic information of C. grijsii, we have sequenced and ass...

Nanostructure arrays have drawn much attention and are promising as new biomaterials in the field of biomedicine. In recent years, numerous experimental studies on the cell behavior of nanostructured arrays (NSs) have been published, describing a wide variety of experimental results. But there are only a few theoretical analyses that elucidate the mechanisms of interactions between cells and nanostructures. Here we present a quantitative thermodynamic model to elucidate the effects of surface topography of nanostructure arrays on cell adhesion. Based on the established model, we studied the equilibrium state of cell adhesion by analyzing the change in free energy during the adhesion process. Theoretical results showed that cell adhesion mode is actually determined by the balance between adhesion energy and deformation energy of the cell membrane. According to the calculated results, a phase diagram of the cell adhesion has been constructed, which can clarify the interrelated effects of the radius and surface distribution density of nanopillars. We can identify the relation between the surface topography of nanostructure arrays and the cell adhesion mode from the phase.

Isolated single quantum dots (QDs) enable the investigation of quantum-optics phenomena for the application of quantum information technologies. In this work, ultralow-density InAs QDs are grown by combining droplet etching epitaxy and the conventional epitaxy growth mode. An extreme low density of QDs (∼106 cm−2) is realized by creating low-density self-assembled nanoholes with the high temperature droplet etching epitaxy technique and then nanohole-filling. The preferred nucleation of QDs in nanoholes has been explained by a theoretical model. Atomic force microscopy and the photoluminescence technique are used to investigate the morphological and optical properties of the QD samples. By varying In coverages, the size of InAs QDs can be controlled. Moreover, with a thin GaAs cap layer, the position of QDs remains visible on the sample surface. Such a low density and surface signature of QDs make this growth method promising for single QD investigation and single dot device fabrication.

Wetting behaviors on a hydrophobic nanopatterned surface, which are of primary consideration in the design of superhydrophobic surfaces, are studied on an analytic model that shows the hole-patterned substrate is more favorable for water droplets to nucleate on the inside of holes based on nucleation theory. After droplet nucleation, the transition from Wenzel state to Cassie–Baxter state may occur during the growth stage. The calculation of the free energy of droplets during the growth stage indicates that the wetting transitions depend on the volume of the droplets, and Wenzel state or Cassie–Baxter state depends on the absolute size and relative size of the geometrical morphology of the nanoholes.

An analytic thermodynamic model has been established to quantitatively investigate the wetting states of droplets on nanopatterned surfaces. Based on the calculations for the free energies of droplets with the Wenzel state and the Cassie-Baxter state, it is found that the size and shape of nanostructured surfaces play crucial roles in wetting states. In detail, for nanohole-patterned surfaces, the deep and thin nanoholes lead to the Cassie-Baxter state, and contrarily, the shallow and thick nanoholes result in the Wenzel state. However, the droplets have the Wenzel state on the patterned surfaces with small height and radii nanopillars and have the Cassie-Baxter state when the height and radii of nanopillars are large. Furthermore, the intuitive phase diagrams of the wetting states of the droplet in the space of surface geometrical parameters are obtained. The theoretical results are in good agreement with the experimental observations and reveal physical mechanisms involved in the effects of nanopatterned surfaces on wetting states, which implies that these studies may provide useful guidance to the conscious design of patterned surfaces to control the wetting states of droplets.

Camellia yuhsienensis Hu is an economically valuable species in the genus Camellia. It is widely used for breeding ornaments and oil varieties. In this study, the complete chloroplast (cp) genome sequence of C. yuhsienensis is assembled and annotated. The whole cp genome of C. yuhsienensis is 156,912 bp in size, composed of a small single copy (SSC) region of 18,296 bp and a large single copy (LSC) region of 86,560 bp, separated by a pair of inverted repeats (IRs, IRA: 86,561–112,588; IRB: 130,885–156,912). The overall GC content of C. yuhsienensis cp genome is 37.3%, with the base content A (31.08%), T (31.63%), C (19.02%), and G (18.27%). The phylogenetic analysis of 15 Camellia species based on 77 protein-coding genes shows that C. yuhsienensis is evolutionarily close to Camellia taliensis.

Zinc oxide (ZnO) nanostructures have been widely studied in biomedical fields due to their special properties. In recent years, ZnO spherical nanoparticles (SNPs) with nano-size as an anti-tumor agent have been widely concerned. While the effects of the non-spherical shaped ZnO nanoparticles on tumor cell death have been rarely reported. Here, we prepared ZnO spiky nanoparticles (SPNPs) as the research subject. We found that the SPNPs showed superiority in killing tumor cells. To be specific, SPNPs presented a long-term cytotoxicity effect on killing tumor cells, as plenty of SPNPs retained on the cell plasma membrane's exterior and still showed toxicity effect on tumor cells after co-incubation multiple times. Moreover, compared to SNPs, it was encouraging that SPNPs still showed stronger cytotoxicity in both simulated circulatory systems of tumor cells and 3D tumor cell spheroids. The stronger toxicity against tumor cells suggested that ZnO SPNPs have more advantages on killing tumor cells as a promising nanomedicine.

To improve the photocatalytic activities of narrow band gap oxide semiconductors for H2 evolution under solar irradiation, it is highly desired to develop effective acceptors for visible light-excited high-energy-level electrons. Herein, we have successfully fabricated Ag-modified TiO2/BiVO4 nanocomposites by putting nanosized BiVO4 into the Ag modified TiO2 sol. Both steady-state and transient-state- surface photovoltage spectra demonstrate that photogenerated charge separation and lifetime of nanosized BiVO4 is promoted when coupling with TiO2 and modifying an appropriate amount of Ag, while the lifetime of photogenerated electrons got prolonged. Interestingly, the resulting Ag-TiO2/BiVO4 nanocomposites exhibit excellent visible light activities for H2 evolution, although the visible light activities of TiO2/BiVO4 one, Ag/BiVO4 and bare BiVO4 are neglectable, indicating that Ag-TiO2 could be utilized as effective acceptors for hydrogen production. It is suggested based on the experimental data that the ...

The hemiwicking state has attracted much interest because of numerous important potential applications in inking, printing, boiling heat transfer, and condensation. However, the mechanism of the emergence of hemiwicking has not been well understood, especially the effects of geometry of patterned surfaces on the hemiwicking state has not been systematically investigated. Here, we presented a new method to study the critical conditions for hemiwicking on patterned surfaces. By minimizing the variation of the free energy, we obtain the corresponding stable height of the hemiwicking film and find that it is easier for a droplet to be in the hemiwicking state if the pillar surface has small spacing, large radius and height, and a small intrinsic contact angle. Our established model is applied to a flat-topped cylindrical pillar-patterned surface, and the modeling results are in well agreement with experiments and other existing theories. Besides, our model is also applied to other kinds of patterned surfaces including hemispherical-topped cylindrical and conical pillars, about which the other existing theories are deficient. Our theoretical results not only are in well agreement with the experimental observations but also provide some important predictions, which implies that the established model could be applicable to understanding the basic physical mechanism of the hemiwicking state and be useful in guiding the design and fabrication of hemiwicking surfaces.

Camellia kissii is cultivated for a long time as an oil crop for edible and industrial oils, and has the functions of high oil production rate and unique health care. The complete chloroplast (cp) genome sequence of C. kissii is 156,961 bp in length with GC content of 39.29%. It presents a quadrate structure, including a large single-copy (LSC) region (86,640 bp), a small single-copy (SSC) region (18,399 bp), and a pair of inverted repeats (IRs) (25,961 bp). Meanwhile, 15 complete chloroplast genome of Camellia was aligned to explore the phylogenetic significance of Camellia. And the genetic relationship between Camellia kissii and Camellia huana was found to be closest.

Camellia brevistyla is an economic species for its seeds with high oil content and ornamental value, which is cultivated widespreadly across southern China. In this study, the complete chloroplast ...

Camellia vietnamensis is an economic woody plant producing high-value edible oils, which is commonly found and cultivated in south areas of China. To provide genetic information for future genetic research, we have sequenced and assembled the complete chloroplast (cp) genome of C. vietnamensis based on the Illumina Hiseq platform. The total genome size is 161,958 bp in length with 37% GC, which contains a large single copy (LSC, 86,657 bp) region, a small single copy (SSC, 13,347 bp) region, and a pair of inverted repeat (IRs, 30,977 bp) regions. It is comprised of 81 protein-coding genes, 44 transfer RNAs and 4 ribosomal RNAs. To obtain the phylogeny relationship, the cp genome of C. vietnamensis has been compared with other Camellia species; the results indicate that C. vietnamensis is closely related to C. taliensis. This study provides fundamental information of C. vietnamensis cp genome, and it is valuable to the molecular phylogenetic and genetic diversity analyses in future.

Background Yield improvement is an ever-important objective of wheat breeding. Studying and understanding the phenotypes and genotypes of yield-related traits has potential for genetic improvement of crops. Results The genotypes of 215 wheat cultivars including 11 founder parents and 106 derivatives were analyzed by the 9 K wheat SNP iSelect assay. A total of 4138 polymorphic single nucleotide polymorphism (SNP) loci were detected on 21 chromosomes, of which 3792 were mapped to single chromosome locations. All genotypes were phenotyped for six yield-related traits including plant height (PH), spike length (SL), spikelet number per spike (SNPS), kernel number per spike (KNPS), kernel weight per spike (KWPS), and thousand kernel weight (TKW) in six irrigated environments. Genome-wide association analysis detected 117 significant associations of 76 SNPs on 15 chromosomes with phenotypic explanation rates (R2) ranging from 2.03 to 12.76%. In comparing allelic variation between founder parents and their derivatives (106) and other cultivars (98) using the 76 associated SNPs, we found that the region 116.0–133.2 cM on chromosome 5A in founder parents and derivatives carried alleles positively influencing kernel weight per spike (KWPS), rarely found in other cultivars. Conclusion The identified favorable alleles could mark important chromosome regions in derivatives that were inherited from founder parents. Our results unravel the genetic of yield in founder genotypes, and provide tools for marker-assisted selection for yield improvement. Electronic supplementary material The online version of this article (10.1186/s12870-018-1234-4) contains supplementary material, which is available to authorized users.

Polyesters, especially poly(lactide) (PLA), are used widely as biodegradable and biocompatible materials, yet their controllable synthesis, especially the stereoselective synthesis of polyesters, is still a challenge. Recently some excellent Lewis pair catalysts for ring-opening polymerization (ROP) of lactide and related cyclic esters have emerged. This review article will highlight the key advances in the ROP catalyzed by Lewis pair compounds with the aim of encouraging the wider application of Lewis pair catalysts in the polymerization of lactide and related cyclic esters.

Creating and manipulating nanowires (NWs) with controllable growth direction and crystal orientation is important to meeting the urgent demands of emerging applications with designed properties. Revealing the underlying mechanisms of the experimentally demonstrated effects of NW diameter and growth temperature on growth direction is crucial for applications. Here, we establish a thermodynamic model to clarify the dependence of NW growth direction on diameter and temperature via the vapor-liquid-solid growth mechanism, enabling analysis of NW critical length between unstable and stable states. At a small critical length, NWs with a large diameter or grown at low temperature tend to grow along the direction, while at a large critical length, NWs with a small diameter or grown at high temperature favor the direction. Specific growth parameters of ZnSe NW have been obtained which can guide the design of functional NWs for applications.

We present a thermodynamic approach to elucidate the effects of the size of magnetic nanoparticles (MNPs), intensity of magnetic field and biologic parameters on endocytosis under a magnetic field. It is found that the external magnetic field not only results in the increase of endocytic rate, but also can alter the internalized pathway. The minimum and maximum radius for receptor-mediated endocytosis can be calculated by simple straightforward expressions. Furthermore, we constructed a phase diagram to clarify the interrelated effects of MNP radius and magnetic field on endocytosis rate. We can identify from the phase the relations among the size of MNPs, intensity of magnetic field and endocytosis rate. Our theoretical findings can provide useful guidance to the design of MNPs for diagnostic agents and drug delivery applications.

Li4SiO4 is considered as one of the most potential high-temperature sorbent materials for CO2 capture from the flue gas of fossil fuel-fired power plants. However, it usually suffers from slow kinetics at low CO2 concentrations. In this work, a series of Na- and K-doped Li4SiO4-based sorbents with Na/Si (or K/Si) atomic ratios of 0.05, 0.1 and 0.2 were prepared by a citrate sol-gel method. The prepared materials were characterized by various techniques, which revealed the presence of Li3NaSiO4 (for Na-doped sorbents) and LiKCO3 (for K-doped sorbents) on the surface of Li4SiO4 particles. All Na- and K-doped Li4SiO4 showed greatly enhanced CO2 sorption rates and capacities in 15% CO2 as compared to the heteroatom-free Li4SiO4, and in particular, the Na-doped sorbents had the fastest rates. The improved performance of K-doped Li4SiO4 resulted from the formation of eutectic Li2CO3-K2CO3 molten carbonates during CO2 sorption, while for Na-doped Li4SiO4, both the carbonation of Li3NaSiO4 and the presence of eutectic Li2CO3-Na2CO3 molten salts contributed to the improvement. In addition, both Na- and K-doped Li4SiO4 exhibited incomplete regeneration during cyclic operation, but the latter had better stability. In this context, we deliberately prepared a Na,K-codoped Li4SiO4-based sorbent with a Na:K:Si atomic ratio of 0.1:0.1:1, which showed fast kinetics and good cyclic stability. During 30 consecutive sorption-regeneration cycles (10 min of sorption in 15% CO2 at 650 °C, 5 min of regeneration in pure N2 at 750 °C), the Na,K-codoped Li4SiO4 presented a stable CO2 capture capacity of 0.22 gCO2/gsorbent after the first 10 cycles.

There is considerable interest in quantum dots incorporated in nanowires for nanolasers and quantum emitters. In this letter, we demonstrate single InAsP quantum dots embedded in InP nanowires grown by metalorganic vapor-phase epitaxy. Despite the abrupt change of growth conditions at the interface, InAsP quantum dots can be grown in pure wurtzite InP nanowires. We develop a model and analyze the effects of the thickness of InAsP quantum dots and the composition of As on the formation of dislocations. Furthermore, the InAsP/InP quantum dot nanowires show bright photoluminescence up to room temperature without any surface passivation. The emission from the quantum dots could be well tuned by adjusting the dot size either vertically or laterally. The study demonstrates the potential of this material system for optoelectronic applications.

Ascorbate peroxidase (APX) acts indispensably in synthesizing L-ascorbate (AsA) which is pivotal to plant stress tolerance by detoxifying reactive oxygen species (ROS). Enhanced activity of APX has been shown to be a key step for genetic engineering of improving plant tolerance. However it needs a deeper understanding on the maintenance of cellular ROS homeostasis in response to stress. In this study, we identified and characterized anAPX(CaAPX) gene fromCamellia azalea. Quantitative real-time PCR (qRT-PCR) analysis showed thatCaAPXwas expressed in all tissues and peaked in immature green fruits; the expression levels were significantly upregulated upon cold and hot stresses. Transgenic plants displayed marked enhancements of tolerance under both cold and heat treatments, and plant growth was correlated withCaAPXexpression levels. Furthermore, we monitored the activities of several ROS-scavenging enzymes includingCu/Zn-SOD,CAT,DHAR, andMDHAR, and we showed that stress tolerance was synchronized with elevated activities of ROS-scavenging. Moreover, gene expression analysis of ROS-scavenging enzymes revealed a role ofCaAPXto orchestrate ROS signaling in response to temperature stresses. Overall, this study presents a comprehensive characterization of cellular response related toCaAPXexpression and provides insights to breed crops with high temperature tolerances.

The wrapping of nanoparticles (NPs) by a membrane is a phenomenon of widespread and generic interest in biology, as well as in a variety of technological applications, such as drug delivery, clinical diagnostics, and biomedical imaging. However, the mechanisms of the interaction between the membrane and NPs are not well understood yet. In this paper, we have presented an analytic thermodynamic model to investigate the wrapping process of NPs by a cell membrane. It is found that the bending energy of the deformed membrane increases nonlinearly with increasing wrapping degree, which leads to a free energy barrier for the wrapping. On the basis of analysis results, the wrapping of NPs can be divided into three types, i.e., impossible wrapping, barrier wrapping, and free wrapping. Furthermore, a phase diagram for the wrapping of NPs has been constructed, which clarifies the interrelated effects of the size and the ligand density of NPs. We hope that this work can provide some help in understanding the physical mechanism of the wrapping of NPs.

We present a quantitative thermodynamic model to elucidate the effects of a nanopatterned surface on bacterial adhesion. Based on the established model, we studied the equilibrium state of rodlike bacterial cells adhered to a nanopillar-patterned surface. Theoretical analyses showed the physical origin of bacterial adhesion on a nanopatterned surface is actually determined by the balance between adhesion energy and deformation energy of the cell membrane. We found that there are enhancement effects on bacterial adhesion to the patterned surface with large radius and small spacing of nanopillars, but suppression effects for nanopillars with a radius smaller than a critical value. In addition, according to our model, a phase diagram has been constructed which can clarify the interrelated effects of the radius and the spacing of nanopillars. The broad agreement with experimental observations implies that these studies would provide useful guidance to the design of nanopatterned surfaces for biomedical applications.

The quest to design and fabricate new antibacterial surfaces is an important task to meet the urgent demands of biomedical applications. Recently, a mechanical mechanism for killing adherent bacteria was discovered on nanopatterned surfaces, but there is a lack of understanding of the bactericidal mechanism. Here we present a quantitative thermodynamic model to study the bactericidal mechanism of nanopatterned surfaces through analyzing the total free energy change of bacterial cells. By comparing the bacterial cells on a flat surface and nanopatterned surface, our theoretical results reveal that cicada wing-like nanopatterned surfaces have more effective bactericidal properties than flat surfaces because a patterned surface leads to a drastic increase of the contact adhesion area. Our model also reveals some details of the influence mechanism, and gives some important information about how to improve the bactericidal properties through designing the morphology of the patterned surface.