Cognizant Fiber-Reinforced Polymer Composites Incorporating Seamlessly Integrated Sensing and Computing Circuitry.

Structural fiber-reinforced polymer (FRP) composite materials consisting of a polymer matrix reinforced with layers of high-strength fibers are used in numerous applications, including but not limited to spacecraft, vehicles, buildings, and bridges. Researchers in the past few decades have suggested the necessary integration of sensors (e.g., fiber optic sensors) in polymer composites to enable health monitoring of composites' performance over their service lives. This work introduces an innovative cognizant composite that can self-sense, compute, and implement decisions based on sensed values. It is a critical step towards smart, resilient infrastructure. We describe a method to fabricate textile sensors with flexible circuitry and a microcontroller within the polymer composite, enabling computational operations to take place in the composite without impacting its integrity. A microstructural investigation of the sensors showed that the amount of oxidative agent and soaking time of the fabric play a major role in the adsorption of polypyrrole (PPy) on fiberglass (FG). XPS results showed that the 10 g ferric chloride solution with 6 h of soaking time had the highest degree of protonation (28%) and, therefore, higher adsorption of PPy on FG. A strain range of 30% was achieved by examining different circuitry and sensor designs for their resistance and strain resolution under mechanical loading. A microcontroller was added to the circuit and then embedded within a composite material. This composite system was tested under flexural loading to demonstrate its self-sensing, computing, and actuation capabilities. The resulting cognizant composite demonstrated the ability to read resistance values and measure strain using the embedded microcontroller and autonomously actuate an LED light when the strain exceeds a predefined limit of 2000 µÎµ. The application of the proposed FRP system would provide in situ monitoring of structural composite components with autonomous response capabilities, as well as reduce manufacturing, production, and maintenance costs.

Prefabricated platinum nanomaterial matrix for MALDI-MS imaging of oligosaccharides and lipids in plant tissues.

Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) can visualize the spatial distribution characteristics of molecules in tissues in situ, in which the matrix plays a key role. In this paper, we propose a platinum nanomaterial pre-coated matrix, which can be prepared in bulk by sputtering platinum nanoparticles onto slides using an ion sputterer and then used for MALDI-MS analysis by placing tissue sections on the matrix. We used this matrix for MALDI-MS imaging analysis of corn kernels and germinated wheat sections, and the results show that triacylglycerides were mainly distributed in the embryo of corn kernels and germinated wheat, and sugars were mainly distributed in the endosperm, with the highest content of disaccharides.It provides a simple and reliable experimental condition for analyzing the distribution of oligosaccharide and lipid components in plant tissues.

Evolution of Thin-Film Wrinkle Patterns on a Soft Substrate: Direct Simulations and the Effects of the Deformation History.

Surface wrinkling instability in thin films attached to a compliant substrate is a well-recognized form of deformation under mechanical loading. The influence of the loading history on the formation of instability patterns has not been studied. In this work, the effects of the deformation history involving different loading sequences were investigated via comprehensive large-scale finite element simulations. We employed a recently developed embedded imperfection technique which is capable of direct numerical predictions of the surface instability patterns and eliminates the need for re-defining the imperfection after each analysis step. Attention was devoted to both uniaxial compression and biaxial compression. We show that, after the formation of wrinkles, the surface patterns could still be eliminated upon complete unloading of the elastic film-substrate structure. The loading path, however, played an important role in the temporal development of wrinkle configurations. With the same final biaxial state, different deformation histories could lead to different surface patterns. The finding brings about possibilities for creating variants of wrinkle morphologies controlled by the actual deformation path. This study also offers a mechanistic rationale for prior experimental observations.

Direct numerical simulations of three-dimensional surface instability patterns in thin film-compliant substrate structures.

A comprehensive numerical study of three-dimensional surface instability patterns is presented. The formation of wrinkles is a consequence of deformation instability when a thin film, bonded to a compliant substrate, is subject to in-plane compressive loading. We apply a recently developed computational approach to directly simulate complex surface wrinkling from pre-instability to post-instability in a straightforward manner, covering the entire biaxial loading spectrum from pure uniaxial to pure equi-biaxial compression. The simulations use embedded imperfections with perturbed material properties at the film-substrate interface. This approach not only triggers the first bifurcation mode but also activates subsequent post-buckling states, thus capable of predicting the temporal evolution of wrinkle patterns in one simulation run. The state of biaxiality is found to influence the surface pattern significantly, and each bifurcation mode can be traced back to certain abrupt changes in the overall load-displacement response. Our systematic study reveals how the loading condition dictates the formation of various instability modes including one-dimensional (1D) sinusoidal wrinkles, herringbone, labyrinth, and checkerboard.

Mineral Composition and Its Control on Nanopores of Marine-Continental Transitional Shale from the Ningwu Basin, North China.

There is a large difference between the sedimentary environment and maturity of organic matter between marine shale and marine-continental transitional shale. It is of great significance to discuss the effect of inorganicminerals on the pores for marine-continental transitional shale gas exploration. In this study, scanning electron microscopy (SEM), low temperature liquid nitrogen adsorption and Xray diffraction (XRD) were conducted on eight marine-continental transitional shale samples from the Ningwu Basin, Shanxi Province, China. The pore structure differences in the different minerals were discussed, and the relationship between the mineral content and pore parameters was analysed. The results show that the mineral composition of shale is dominated by clay minerals, quartz, carbonate minerals and a small amount of pyrite. The clay minerals content is between 39.5% and 77.0%, with an average of 59.9%. The quartz content ranges from 21.8% to 47.8%, with an average of 31.9%. The carbonate minerals content in shale is between 0.6% and 23.9%, and the average is 6.3%. The clay minerals are composed of mixed illite-montmorillonite layer, kaolinite and chlorite. The content of mixed illite-montmorillonite layer is between 13.8% and 27.4%, with an average of 20.4%. The kaolinite content ranges from 57.0% to 86.2%, with an average of 76.0%. The content of chlorite is between 0 and 15.6%, with an average of 5.7%. The types of pores are mainly intergranular pores and interlaminar pores, which are mostly presented as slit and parallel plates. The mixed illite-montmorillonite layer contributes more to the specific surface area, which is favourable for shale gas adsorption. The pores in kaolinite are more developed than those of the mixed illite-montmorillonite layer, but the pore diameter is relatively large. The quartz granule has a complete crystal type, and intergranular pores with a large pore size are often developed at the mineral contacts. Compared with clay minerals and quartz, the pore development in the carbonate minerals is relatively poor and develops more micro-fractures. The pyrite contributes a certain number of intergranular pores and mold pores.

Metallic glass coating for improving diamond dicing performance.

This is the first report on the coating of diamond dicing blades with metallic glass (MG) coating to reduce chipping when used to cut Si, SiC, sapphire, and patterned sapphire substrates (PSS). The low coefficient-of-friction (CoF) of Zr-based MG-coated dicing blades was shown to reduce the number and size of chips, regardless of the target substrate. Overall, SiC, sapphire and PSS were most affected by chipping, due to the fact that higher cutting forces were needed for the higher hardness of SiC, sapphire and PSS. Compared to the bare blade, the MG coating provided the following reductions in chipping area: Si (~ 23%), SiC (~ 36%), sapphire (~ 45%), and PSS (~ 33%). The proposed coating proved particularly effective in reducing chips of larger size (> 41 µm in chipping width), as indicated by an ~ 80% reduction when cutting sapphire. Small variations in kerf angle and depth demonstrate the durability of the coated blades, which would no doubt enhance consistency in dicing performance and extend the blade lifespan. Finite-element modeling revealed significant reductions in tensile stress and elastic-plastic deformation during dicing, thanks to a lower CoF.

Instabilities of Thin Films on a Compliant Substrate: Direct Numerical Simulations from Surface Wrinkling to Global Buckling.

For structures consisting of a thin film bonded to a compliant substrate, wrinkling of the thin film is commonly observed as a result of mechanical instability. Although this surface undulation may be an undesirable feature, the development of new functional devices has begun to take advantage of wrinkled surfaces. The wrinkled structure also serves to improve mechanical resilience of flexible devices by suppressing crack formation upon stretching and bending. If the substrate has a reduced thickness, buckling of the entire structure may also occur. It is important to develop numerical design tools for predicting both wrinkle and buckle formations. In this paper we report a comprehensive finite element-based study utilizing embedded imperfections to directly simulate instabilities. The technique overcomes current computational challenges. The temporal evolution of the wrinkling features including wavelength and amplitude, as well as the critical strains to trigger the surface undulation and overall structural buckling, can all be predicted in a straightforward manner. The effects of model dimensions, substrate thickness, boundary condition, and composite film layers are systematically analyzed. In addition to the separate wrinkling and buckling instabilities developed under their respective geometric conditions, we illustrate that concurrent wrinkling and buckling can actually occur and be directly simulated. The correlation between specimen geometry and instability modes, as well as how the deformation increment size can influence the simulation result, are also discussed.

Donor Halogenation Effects on Electronic Structures and Electron Process Rates of Donor/C60 Heterojunction Interface: A Theoretical Study on F nZnPc ( n = 0, 4, 8, 16) and Cl nSubPc ( n = 0, 6).

Molecular engineering is significantly important for developing electron donor and acceptor materials of active layers in organic photovoltaics (OPVs). The OPVs based on halogenated donors frequently produced high power conversion efficiencies. Here, based upon density functional theory calculations with optimally tuned range separation parameters and solid polarization effects, we studied the effects of donor halogenation on molecular geometries, electronic structures, excitation, and spectroscopic properties for F nZnPc ( n = 0, 4, 8, 16) and Cl nSubPc ( n = 0, 6) monomers and the complexes with C60 as well as the photoinduced direct charge transfer (CT), exciton dissociation (ED), and charge recombination (CR) processes that were described by rate constants calculated using Marcus theory. The tiny differences of the molecular orbital energy gap, excitation, and spectroscopic properties of F nZnPc ( n = 0, 4, 8, 16) and Cl nSubPc ( n = 0, 6) monomers suggest that halogenation cannot effectively tune the electronic and optical gap but the significant decrease of molecular orbital energies support the idea that halogenation has a remarkable influence on the energy level alignment at heterojunction interfaces. The halogenation also enhances intermolecular binding energies between C60 and donors and increases the CT excitation energies of donor/C60 complexes, which are favorable for improving open circuit voltage. Furthermore, for F nZnPc/C60 ( n = 0, 4, 8, 16) and SubPc/C60 ( n = 0, 6) complexes, the CR rates dramatically decrease (several orders) with increasing number of halogen atoms (except for F16ZnPc/C60), meaning suppression of CR processes by halogenation. As for the special case of F16ZnPc/C60, it underlines the importance of fluorination degree in molecular design of donor materials. This study provides a theoretical understanding of the halogenation effects of donors in OPVs and may be helpful in molecular design for electron donor materials.

Biomechanical Heterogeneity of Living Cells: Comparison between Atomic Force Microscopy and Finite Element Simulation.

Atomic force microscopy (AFM) indentation is a popular method for characterizing the micromechanical properties of soft materials such as living cells. However, the mechanical data obtained from deep indentation measurements can be difficult and problematic to interpret as a result of the complex geometry of a cell, the nonlinearity of indentation contact, and constitutive relations of heterogeneous hyperelastic soft components. Living MDA-MB-231 cells were indented by spherical probes to obtain morphological and mechanical data that were adopted to build an accurate finite element model (FEM) for a parametric study. Initially, a 2D-axisymmetric numerical model was constructed with the main purpose of understanding the effect of geometrical and mechanical properties of constitutive parts such as the cell body, nucleus, and lamellipodium. A series of FEM deformation fields were directly compared with atomic force spectroscopy in order to resolve the mechanical convolution of heterogeneous parts and quantify Young's modulus and the geometry of nuclei. Furthermore, a 3D finite element model was constructed to investigate indentation events located far from the axisymmetric geometry. In this framework, the joint FEM/AFM approach has provided a useful methodology and a comprehensive characterization of the heterogeneous structure of living cells, emphasizing the deconvolution of geometrical structure and the true elastic modulus of the cell nucleus.

Molecular Docking toward Panchromatic Dye Sensitizers for Solar Cells Based upon Tetraazulenylporphyrin and Tetraanthracenylporphyrin.

Novel dye sensitizers are highly expected in the development of dye-sensitized solar cells (DSSCs) because dye sensitizers can significantly affect the power conversion efficiency (PCE). Here, the molecular docking strategy is applied to design panchromatic dye sensitizers for DSSCs to improve light-harvesting efficiency covering the full solar spectrum. Considering the broad absorption bands of tetraanthracenylporphyrins (TAnPs) and tetraazuleneporphyrins (TAzPs), based upon porphyrin dye sensitizer YD2-o-C8, the panchromatic dye sensitizers coded as H2(TAnP)-α, H2(TAzP)-γ, H2(TAzP)-ε, and H2(TAzP)-δ are designed by the substitution of the porphyrin-ring in YD2-o-C8 with TAnPs and TAzPs moieties at different positions. The geometries, electronic structures, and excitation properties of the designed dye sensitizers are investigated using density functional theory (DFT) and time-dependent DFT methods. The analysis of geometries, conjugation lengths, electronic structures, absorption spectra, transition configurations, exciton binding energies, and free energy variations for electron injection and dye regeneration supports that the designed molecules are effective to be applied as potential candidates of dye sensitizers for DSSCs. Among the designed dye sensitizers, H2(TAzP)-γ and H2(TAnP)-α must have the better performance in DSSCs.

[Effects of tetramethylpyrazine on trigeminal neuralgia induced by chronic constriction injury of infraorbital nerve in rats].

Trigeminal neuralgia (TN) is a kind of recurrent transient and severe pain that is limited to the trigeminal nerve in one or more branches. The clinical incidence of TN is high, which seriously affects the quality of life of the patients and is difficult to cure. The present study investigated the effects of tetramethylpyrazine (TMP) on TN induced by chronic constriction injury of the infraorbital nerve (ION-CCI) in rats. Adult male Sprague-Dawley rats were randomly assigned to four groups: sham, sham treated with TMP (Sham+TMP), TN model (TN), and TN treated with TMP (TN+TMP). The rat TN model was established by ION-CCI and TMP (50 mg/kg) was injected intraperitoneally once a day for 2 weeks after operation. The mechanical response threshold was tested by the electronic von Frey filaments. The expression of CGRP in the trigeminal ganglia (TGs) of rats on the operative side was detected by RT-PCR, immunohistochemical staining and Western blot. In 15 days after operation, TN group showed a robust decrease in mechanical response threshold as compared with sham group. From day 9 to day 15 after operation, TMP treatment significantly suppressed the TN-induced mechanical hyperalgesia (P < 0.05). On day 15 after operation, RT-PCR, immunohistochemical staining and Western blot analysis showed an obvious increase in expression level of CGRP in TGs of TN group compared with sham group, which was downregulated by TMP treatment (P < 0.05). These results suggested that TMP might have a therapeutic potential for the treatment of TN through regulating CGRP expression in the TGs.

Emodin inhibits the expression of receptor and calcitonin-gene-related peptide release in trigeminal ganglia of trigeminal neuralgia rats.

Trigeminal neuralgia (TN) is one of the most intense forms of facial pain. It has been reported that the P2X3 receptor plays a crucial role in facilitating pain transmission, and the calcitonin-gene-related peptide (CGRP) from trigeminal ganglia (TGs) might perform differing function in nociceptive afferent input transmission. The present study investigated whether emodin can affect TN pain transmission by suppressing the expression of P2X3 receptors and CGRP in TGs. Chronic constriction injury of the infraorbital branch of the trigeminal nerve (CCI-ION) was used as TN model. The TN rats were randomly divided into the following 4 groups: (1) a sham group (Sham), (2) a sham rats treated with emodin group (TN + E), (3) a TN rats treated with 0.5% sodium carboxymethyl cellulose (CMC) as vehicle group (TN) and (4) a TN rats treated with emodin group (TN + E). The mechanical hyperalgesia threshold of TN rats was tested by Electric Von Frey filaments. The change of the expression of P2X3 receptors and CGRP in rat's TG was detected with RT-PCR, immunohistochemical staining, and Western blotting. The phosphorylation of p38 and ERK1/2 pathway of TG was detected by Western blotting. After CCI-ION injury, the threshold of mechanical hyperalgesia for the territory of ligated infraorbital nerve in TN group decreased significantly compared with that in sham group. On day 14 after operation of CCI-ION, there was also an evident increase in the expression of P2X3 receptors and CGRP in the TG of TN group. However after treatment with emodin, the response of mechanical hyperalgesia of TN rats was clearly increased while the enhanced expression of P2X3 receptor and CGRP in TN rats was significantly decreased. The phosphorylation of p38 and ERK1/2 in TN group was stronger than that in Sham group. But these phosphorylation changes in the TN rats were much weaker after treatment with emodin. In conclusion, P2X3 receptor may cooperate with CGRP in the pain transmission of TN, and emodin can inhibit the expression and activation of P2X3 receptor and CGRP in TG to relieve TN.

Non-stick syringe needles: Beneficial effects of thin film metallic glass coating.

This paper reports on the use of Zr-based (Zr53Cu33Al9Ta5) thin film metallic glass (TFMG) for the coating of syringe needles and compares the results with those obtained using titanium nitride and pure titanium coatings. TFMG coatings were shown to reduce insertion forces by ∼66% and retraction forces by ∼72%, when tested using polyurethane rubber block. The benefits of TFMG-coated needles were also observed when tested using muscle tissue from pigs. In nano-scratch tests, the TFMG coatings achieved a coefficient of friction (COF) of just ∼0.05, which is about one order of magnitude lower than those of other coatings. Finite-element modeling also indicates a significant reduction in injection and retraction forces. The COF can be attributed to the absence of grain boundaries in the TFMG coating as well as a smooth surface morphology and low surface free energy.

The electronic structure engineering of organic dye sensitizers for solar cells: The case of JK derivatives.

The design and development of novel dye sensitizers are effective method to improve the performance of dye-sensitized solar cells (DSSCs) because dye sensitizers have significant influence on photo-to-current conversion efficiency. In the procedure of dye sensitizer design, it is very important to understand how to tune their electronic structures and related properties through the substitution of electronic donors, acceptors, and conjugated bridges in dye sensitizers. Here, the electronic structures and excited-state properties of organic JK dye sensitizers are calculated by using density functional theory (DFT) and time dependent DFT methods. Based upon the calculated results, we investigated the role of different electronic donors, acceptors, and π-conjugated bridges in the modification of electronic structures, absorption properties, as well as the free energy variations for electron injection and dye regeneration. In terms of the analysis of transition configurations and molecular orbitals, the effective chromophores which are favorable for electron injection in DSSCs are addressed. Meanwhile, considering the absorption spectra and free energy variation, the promising electronic donors, π-conjugated bridges, and acceptors are presented to design dye sensitizers.

[Evolutionary analysis of neuraminidase gene of A/H7N9 influenza virus].

In 2013, the World Health Organization reported the first case of human infection with a new influenza A (H7N9) virus in China. This has caused damage and panic within certain areas in China. Therefore, analysis of this virus with bioinformatics technology is very necessary. Neuraminidase (NA) is one of the most important antigens of the influenza virus and an important target for anti-flu drugs. In this study, the nucleotide and protein sequences of NA gene of A/H7N9 influenza viruses were retrieved from the NCBI database, and MEGA 5.0 software was employed to construct a phylogenetic tree based on the nucleotide coding sequence; BioEdit software was used to align the nucleotide and protein sequences of NA and calculate the homologies of nucleotides and amino acids and then to analyze the important mutation sites of NA gene. The results demonstrated that the spread of influenza virus H7N9 showed certain geographical and temporal relations. The H7N9 virus isolated from China in 2013 belonged to Euroasiatic serotype, and its NA stalk region hadobvious variation, which may be one of the reasons that this virus infects human. These analyses may be very helpful for understanding the evolutionary relationship and mutation trend of A/H7N9 influenza viruses.

Understanding the electronic structures and absorption properties of porphyrin sensitizers YD2 and YD2-o-C8 for dye-sensitized solar cells.

The electronic structures and excitation properties of dye sensitizers determine the photon-to-current conversion efficiency of dye sensitized solar cells (DSSCs). In order to understand the different performance of porphyrin dye sensitizers YD2 and YD2-o-C8 in DSSC, their geometries and electronic structures have been studied using density functional theory (DFT), and the electronic absorption properties have been investigated via time-dependent DFT (TDDFT) with polarizable continuum model for solvent effects. The geometrical parameters indicate that YD2 and YD2-o-C8 have similar conjugate length and charge transfer (CT) distance. According to the experimental spectra, the HSE06 functional in TDDFT is the most suitable functional for describing the Q and B absorption bands of porphyrins. The transition configurations and molecular orbital analysis suggest that the diarylamino groups are major chromophores for effective CT excitations (ECTE), and therefore act as electron donor in photon-induced electron injection in DSSCs. The analysis of excited states properties and the free energy changes for electron injection support that the better performance of YD2-o-C8 in DSSCs result from the more excited states with ECTE character and the larger absolute value of free energy change for electron injection.

Electronic structures and optical properties of organic dye sensitizer NKX derivatives for solar cells: a theoretical approach.

The photon to current conversion efficiency of dye-sensitized solar cells (DSCs) can be significantly affected by dye sensitizers. The design of novel dye sensitizers with good performance in DSCs depend on the dye's information about electronic structures and optical properties. Here, the geometries, electronic structures, as well as the dipole moments and polarizabilities of organic dye sensitizers C343 and 20 kinds of NKX derivatives were calculated using density functional theory (DFT), and the computations of the time dependent DFT with different functionals were performed to explore the electronic absorption properties. Based upon the calculated results and the reported experimental work, we analyzed the role of different conjugate bridges, chromophores, and electron acceptor groups in tuning the geometries, electronic structures, optical properties of dye sensitizers, and the effects on the parameters of DSCs were also investigated.

Ultra-long Pt nanolawns supported on TiO2-coated carbon fibers as 3D hybrid catalyst for methanol oxidation.

In this study, TiO2 thin film photocatalyst on carbon fibers was used to synthesize ultra-long single crystalline Pt nanowires via a simple photoreduction route (thermally activated photoreduction). It also acted as a co-catalytic material with Pt. Taking advantage of the high-aspect ratio of the Pt nanostructure as well as the excellent catalytic activity of TiO2, this hybrid structure has the great potential as the active anode in direct methanol fuel cells. The electrochemical results indicate that TiO2 is capable of transforming CO-like poisoning species on the Pt surface during methanol oxidation and contributes to a high CO tolerance of this Pt nanowire/TiO2 hybrid structure.

Kinetic study of Pt nanocrystal deposition on Ag nanowires with clean surfaces via galvanic replacement.

Without using any templates or surfactants, this study develops a high-yield process to prepare vertical Ag-Pt core-shell nanowires (NWs) by thermally assisted photoreduction of Ag NWs and successive galvanic replacement between Ag and Pt ions. The clean surface of Ag nanowires allows Pt ions to reduce and deposit on it and forms a compact sheath comprising Pt nanocrystals. The core-shell structural feature of the NWs thus produced has been demonstrated via transmission electron microscopy observation and Auger electron spectroscopy elemental analysis. Kinetic analysis suggests that the deposition of Pt is an interface-controlled reaction and is dominated by the oxidative dissolution of Ag atoms. The boundaries in between Pt nanocrystals may act as microchannels for the transport of Ag ions during galvanic replacement reactions.

Electronic structures and absorption properties of three kinds of ruthenium dye sensitizers containing bipyridine-pyrazolate for solar cells.

The geometries, electronic structures and the electronic absorption spectra of three kinds of ruthenium complexes, which contain tridentate bipyridine-pyrazolate ancillary ligands, were studied using density functional theory (DFT) and time-dependent DFT. The calculated results indicate that: (1) the strong conjugated effects are formed across the pyrazoalte-bipyridine groups; (2) the interfacial electron transfer between electrode and the dye sensitizers is an electron injection processes from the excited dyes to the conduction band of TiO2; (3) the absorption bands in visible region have a mixed character of metal-to-ligand charge transfer and ligand-to-ligand charge transfer, but the main character of absorption bands near UV region ascribe to π→π* transitions; (4) introducing pyrazolate and -NCS groups are favorable for intra-molecular charge transfer, and they are main chromophores that contribute to the sensitization of photon-to-current conversion processes, but introducing -Cl and the terminal group -CF3 are unfavorable to improve the dye performance in dye sensitized solar cells.