SERS-Enabled Lab-on-a-Chip Systems

Surface-enhanced Raman spectroscopy (SERS) has been combined with microfluidic Lab-on-a-Chip (LoC) systems for sensitive optofluidic detection for more than a decade. However, most microfluidic SERS devices still suffer from analyte contamination and signal irreproducibility. In recent years, both the microfluidics and SERS communities have developed their own solutions that are complementary to each other; their combination even has potential for commercialization. In this review, the recent advances in both fields are summarized with regard to the development of reliable multifunctional SERS-enabled LoC systems and their broad applications. Starting from SERS fundamentals, reproducible SERS substrates and dynamic microfluidic trapping are discussed. Based on their combination, on-chip applications beyond SERS are presented, and insight can be gained into the commercialization of portable SERS chips.postprin

Growth and physiological responses to water and nutrient stress in oil palm

The research was conducted to detect changes in growth, physiology and nutrient concentration in response to two watering regimes (well-watered and water-stress conditions) and to two nutrient regimes (with or without fertilization) of oil palm. Under stress conditions, changes in plant growth, dry matter allocation, relative water content, leaf relative conductivity, leaf N, P and K concentration are usually observed. These characteristics and related parameters were determined and the experiment results are listed as follows: (1) fertilization promoted the growth of oil palm under well-watered conditions, while under water stress conditions its effects on growth was negative. The ratio of root/shoot was increased under water stress condition; (2) relative water content and chlorophyll a/b content were gradually decreased while leaf relative conductivity was increased quickly under water and nutrient stress conditions during the experiment. It is obvious that water stress had a greater influence than nutrient stress on these parameters; (3) water and nutrient stress decreased leaf nitrogen and phosphorus concentration but increased potassium concentration; the combination of water and nutrient stress made significant effects on nitrogen and phosphorus concentration, but no significant effects on potassium concentration. Moreover, deficiency of both water and nutrients in combination had the greatest impact on changes in these traits of oil palm.Key words: Plant growth, physiology response, nutrient concentration, water stress, nutrient stress

Development and Validation of a Method for Profiling Post-Translational Modification Activities Using Protein Microarrays

Background: Post-translational modifications (PTMs) impact on the stability, cellular location, and function of a protein thereby achieving a greater functional diversity of the proteome. To fully appreciate how PTMs modulate signaling networks, proteome-wide studies are necessary. However, the evaluation of PTMs on a proteome-wide scale has proven to be technically difficult. To facilitate these analyses we have developed a protein microarray-based assay that is capable of profiling PTM activities in complex biological mixtures such as whole-cell extracts and pathological specimens.Methodology/Principal Findings: In our assay, protein microarrays serve as a substrate platform for in vitro enzymatic reactions in which a recombinant ligase, or extracts prepared from whole cells or a pathological specimen is overlaid. The reactions include labeled modifiers (e. g., ubiquitin, SUMO1, or NEDD8), ATP regenerating system, and other required components (depending on the assay) that support the conjugation of the modifier. In this report, we apply this methodology to profile three molecularly complex PTMs (ubiquitylation, SUMOylation, and NEDDylation) using purified ligase enzymes and extracts prepared from cultured cell lines and pathological specimens. We further validate this approach by confirming the in vivo modification of several novel PTM substrates identified by our assay.Conclusions/Significance: This methodology offers several advantages over currently used PTM detection methods including ease of use, rapidity, scale, and sample source diversity. Furthermore, by allowing for the intrinsic enzymatic activities of cell populations or pathological states to be directly compared, this methodology could have widespread applications for the study of PTMs in human diseases and has the potential to be directly applied to most, if not all, basic PTM research

Slow cooling and efficient extraction of C-exciton hot carriers in MoS2 monolayer

In emerging optoelectronic applications, such as water photolysis, exciton fission and novel photovoltaics involving low-dimensional nanomaterials, hot-carrier relaxation and extraction mechanisms play an indispensable and intriguing role in their photo-electron conversion processes. Two-dimensional transition metal dichalcogenides have attracted much attention in above fields recently; however, insight into the relaxation mechanism of hot electron-hole pairs in the band nesting region denoted as C-excitons, remains elusive. Using MoS2 monolayers as a model two-dimensional transition metal dichalcogenide system, here we report a slower hot-carrier cooling for C-excitons, in comparison with band-edge excitons. We deduce that this effect arises from the favourable band alignment and transient excited-state Coulomb environment, rather than solely on quantum confinement in two-dimension systems. We identify the screening-sensitive bandgap renormalization for MoS2 monolayer/graphene heterostructures, and confirm the initial hot-carrier extraction for the C-exciton state with an unprecedented efficiency of 80%, accompanied by a twofold reduction in the exciton binding energy

Experimental study on Shear capacity of cementitious composite RPC Beams using high strength steel

Reactive Powder Concrete (RPC) is a special concrete where the microstructure is optimized by precise gradation of all particles in the mix to yield maximum density. Therefore, Reactive Powder Concrete exhibits ultra-high strength and durability. The high strength reinforcement (HSR) has high strength and good plastic deformation properties. The combination of RPC and high strength reinforcement can fully exploit their respective advantages. At present, there is little research on shear capacity of HSR reinforced RPC concrete beams, neither are design guidelines for this type of structure. Therefore, it is imperative to make detailed investigations on the shear capacity of this type of concrete. In this paper, thirty-two full scale shear tests of high strength steel reinforced RPC beams were carried out. The parameters affecting the shear capacity of this type of structures were studied, the major failure modes of this type structure due to shear are identified

Soil-water interacting use patterns driven by Ziziphus jujuba on the Chenier Island in the Yellow River Delta, China

The determination of water use patterns of plants in a coastal ecosystem is critical to our understanding of local eco-hydrological processes and predicting trends in ecological succession under the background of global climate change. The water use patterns of Ziziphus jujuba, the dominant species on the Chenier Island in the Yellow River Delta, were examined following summer rainfall events. Stable oxygen isotope analysis was employed to analyze the effects of rainfall on the stable isotopic composition in potential water sources in Z. jujuba. The IsoSource model was used to estimate the contributions of potential water sources for xylem water in Z. jujuba. The results showed heavy rainfall could recharge both soil and groundwater but contributed little to the O-18 values in deep soil water (60-100cm) and groundwater. Light rainfall had an effect only on surface soil water (0-40cm). Z. jujuba mainly absorbed deep soil water on non-rainy days. Rainwater became the predominant water source for Z. jujuba during and immediately after heavy rainfall. Switching the plant's main water source between deep soil water and rainwater provided Z. jujuba with a competitive advantage and improved the water use efficiency of Z. jujuba in this coastal ecosystem

Attitudes toward brushing children's teeth—A study among parents with immigrant status in Norway

Background Early childhood caries (ECC) is a common chronic childhood disease with multifactorial etiology including poor parental dietary and hygiene behaviors. Aim This study aimed to assess toothbrushing‐related perceptions among parents with immigrant background living in Norway. Design A structured interview was performed with immigrant parents to assess their oral health‐related knowledge, beliefs, and attitude toward toothbrushing. Immigrant parents of non‐Western origin with newborn infants (0‐6 months) were included in this study. Results Of those interviewed, 66% chose to participate and they were found to have an average favorable attitudes, subjective norms, and strong perceptions of control related to child's tooth brushing with reported means of (3.3), (3.6), and (4.6), respectively. They had on average low indulgence (mean 7.8) with respect to this behavior and a relatively high level of knowledge (mean 6.9). Parents with strong intention toward toothbrushing (61%) had on average more frequent oral hygiene behavior than parents with weak intentions. Conclusion Parents with non‐Western origin have adequate knowledge and intention toward toothbrushing, although some have an unsatisfactory attitude, which might affect the oral health of their children negatively. Culture and habits are contributing factors in ECC and should be addressed in oral health prevention policies.publishedVersio

Molecular Valves for Controlling Gas Phase Transport Made from Discrete Angstrom-Sized Pores in Graphene

An ability to precisely regulate the quantity and location of molecular flux is of value in applications such as nanoscale 3D printing, catalysis, and sensor design. Barrier materials containing pores with molecular dimensions have previously been used to manipulate molecular compositions in the gas phase, but have so far been unable to offer controlled gas transport through individual pores. Here, we show that gas flux through discrete angstrom-sized pores in monolayer graphene can be detected and then controlled using nanometer-sized gold clusters, which are formed on the surface of the graphene and can migrate and partially block a pore. In samples without gold clusters, we observe stochastic switching of the magnitude of the gas permeance, which we attribute to molecular rearrangements of the pore. Our molecular valves could be used, for example, to develop unique approaches to molecular synthesis that are based on the controllable switching of a molecular gas flux, reminiscent of ion channels in biological cell membranes and solid state nanopores.Comment: to appear in Nature Nanotechnolog

Genome-wide signatures of convergent evolution in echolocating mammals

Evolution is typically thought to proceed through divergence of genes, proteins, and ultimately phenotypes(1-3). However, similar traits might also evolve convergently in unrelated taxa due to similar selection pressures(4,5). Adaptive phenotypic convergence is widespread in nature, and recent results from a handful of genes have suggested that this phenomenon is powerful enough to also drive recurrent evolution at the sequence level(6-9). Where homoplasious substitutions do occur these have long been considered the result of neutral processes. However, recent studies have demonstrated that adaptive convergent sequence evolution can be detected in vertebrates using statistical methods that model parallel evolution(9,10) although the extent to which sequence convergence between genera occurs across genomes is unknown. Here we analyse genomic sequence data in mammals that have independently evolved echolocation and show for the first time that convergence is not a rare process restricted to a handful of loci but is instead widespread, continuously distributed and commonly driven by natural selection acting on a small number of sites per locus. Systematic analyses of convergent sequence evolution in 805,053 amino acids within 2,326 orthologous coding gene sequences compared across 22 mammals (including four new bat genomes) revealed signatures consistent with convergence in nearly 200 loci. Strong and significant support for convergence among bats and the dolphin was seen in numerous genes linked to hearing or deafness, consistent with an involvement in echolocation. Surprisingly we also found convergence in many genes linked to vision: the convergent signal of many sensory genes was robustly correlated with the strength of natural selection. This first attempt to detect genome-wide convergent sequence evolution across divergent taxa reveals the phenomenon to be much more pervasive than previously recognised

Panoramic Human Structure Maintenance based on Invariant Features of Video Frames

[[abstract]]Panoramic photography is becoming a very popular and commonly available feature in the mobile handheld devices nowadays. In traditional panoramic photography, the human structure often becomes messy if the human changes position in the scene or during the combination step of the human structure and natural background. In this paper, we present an effective method in panorama creation to maintain the main structure of human in the panorama. In the proposed method, we use an automatic method of feature matching, and the energy map of seam carving is used to avoid the overlapping of human with the natural background. The contributions of this proposal include automated panoramic creation method and it solves the human ghost generation problem in panorama by maintaining the structure of human by energy map. Experimental results prove that the proposed system can be effectively used to compose panoramic photographs and maintain human structure in panorama.[[incitationindex]]SCI[[booktype]]電子