Search

This work unveils critical insights through spectroscopic analysis highlighting electrical phenomena and oxygen vacancy generation in self-aligned fully solution-processed oxide thin-film transistors (TFTs). Ar inductively coupled plasma treatment was conducted to fabricate an amorphous indium zinc oxide (a-InZnO) TFT in a self-aligned process. Results showed that the Ar plasma-activated a-InZnO regions became conductive, which means that a homogeneous layer can act as both channel and electrode in the device. Several techniques were employed to probe specific aspects of the source-drain-channel interface in the fully solution-processed TFTs. X-ray absorption near-edge structure and Extended X-ray absorption fine structure were conducted to investigate the existence of oxygen vacancies, which is the main driving factor in inducing a conductive region. X-ray photoelectron spectroscopy was also used to explain the oxygen refilling mechanism. Ultraviolet Photoelectron Spectroscopy was conducted to analyze the valence band maximum and work function. Integration of these results facilitated the construction of the energy band diagram at the interface, wherein a Schottky barrier height of ∼0.37 eV was observed. By leveraging these techniques, insights into the electronic properties and performance of next-generation transistors are gained, enabling their future widespread adoption.

All-solid-state batteries with nonflammable inorganic solid electrolytes are the key to addressing the safety issues of lithium-ion batteries with flammable organic liquid electrolytes. However, conventional electrode materials suffer from substantial volume changes during Li + (de)intercalation, leading to mechanical failure of interfaces between electrode materials and solid electrolytes and then severe performance degradation. In this study, we report strain-free charge storage via the interfaces between transition metal carbides (MXenes) and solid electrolytes, where MXene shows negligible structural changes during Li + (de)intercalation. Operando scanning electron transmission microscopy with electron energy-loss spectroscopy reveals the pillar effect of trapped Li + in the interlayer spaces of MXene to achieve the strain-free features. An all strain-free solid-state battery, which consists of a strain-free Ti 3 C 2 T x negative electrode and a strain-free disordered rocksalt Li 8/7 Ti 2/7 V 4/7 O 2 positive electrode, demonstrates long-term stable operation while preserving the interfacial contact between electrode materials and solid electrolytes.

Martensitic transformation with volume expansion plays a crucial role in enhancing the mechanical properties of steel and partially stabilized zirconia. We believe that a similar concept could be applied to unexplored nonoxide materials. Herein, we report the stress-induced martensitic transformation of monoclinic Na 3 YCl 6 with an ∼3.4% expansion. In situ synchrotron X-ray diffraction and atomistic simulations showed that anisotropic crystallographic transformation from monoclinic to rhombohedral Na 3 YCl 6 occurs exclusively under uniaxial pressure; no effect is observed under hydrostatic pressure conditions. The uniaxially pressed powder compact of monoclinic Na 3 YCl 6 showed a large indentation impression and low Young's modulus, in contrast to its high bulk modulus, suggesting that these unique mechanical properties are induced by the martensitic transformation.

Recent advances in "hybrid-improper" ferroelectricity in Dion-Jacobson (DJ)-type layered perovskites have caused renewed interest in the search for new ferroelectrics. Here, we present an approach for the tailored synthesis of a new homologous series of DJ-type layered perovskites Cs(Bi 2 Sr n -3 )(Ti n -1 Nb)O 3 n +1 . Starting from CsBi 2 Ti 2 NbO 10 ( n = 3), higher-order homologous phases with n = 4 and 5 were successfully synthesized by repeated solid-state calcination with SrTiO 3 . Characterizations by X-ray diffraction, electron diffraction, transmission electron microscopy, Raman scattering, and second harmonic generation showed the detailed structural features in Cs(Bi 2 Sr n -3 )(Ti n -1 Nb)O 3 n +1 , and the polar structures could be stabilized by proper or hybrid-improper ferroelectricity, depending on the odd or even number of the perovskite layers. Our results provide important insights into the competition between the different mechanisms and the consequences of the ferroelectric properties in homologous layered perovskites.

Long nanowires offer an increased surface area for biomolecule immobilization, facilitating enhanced binding capacity and sensitivity in the detection of target analytes. However, robust long-nanowire fabrication remains a significant challenge. In this paper, we developed a novel construction of a micro chemical pen (MCP), called a clean-assisted micro chemical pen (CAMCP), for robust long-nanowire fabrication. CAMCP, based on localized hydrodynamic flow confinement, was conducted by incorporating a clean phase to effectively dissolve aggregated silver particles in the aspiration channel's shell, thereby enhancing the MCP's longevity by 60.84%, allowing for an 840 μm extension in nanowire patterning capability. A 4600-aspect ratio (length:1200 μm, width: 260 nm) nanowire was fabricated by CAMCP and utilized as a nanowire sensor, showing a 39.7% increase in IgA detection sensitivity compared to a 3000-aspect ratio sensor. Furthermore, the longer nanowire sensor exhibited enhanced signal responses, a higher signal-to-noise ratio, and a lower limit of detection (LOD). The preponderant bioassay performances of the longer nanowire sensor in bioassays, facilitated by CAMCP, open up its possibilities for chemical-synthesis nanowires (NWs) in ultrasensitive biodetection.

Though considerable progress has been achieved on gas molecule recognition by electronic nose (e-nose) comprised of nonselective (metal oxide) semiconductor chemiresistors, extracting adequate molecular features within short time (<1 s) remains a big obstacle, which hinders the emerging e-nose applications in lethal or explosive gas warning. Herein, by virtue of the ultrafast (∼20 μs) thermal relaxation time of self-heated WO 3 -based chemiresistors fabricated via oblique angle deposition, instead of external heating, self-heating temperature modulation has been proposed to generate sufficient electrical response features. Accurate discrimination of 12 gases (including 3 xylene isomers with the same function group and molecular weight) has been readily achieved within 0.5-1 s, which is one order faster than the state-of-the-art e-noses. A smart wireless e-nose, capable of instantaneously discriminating target gas in ambient air background, has been developed, paving the way for the practical applications of e-nose in the area of homeland security and public health.

Carbon nanotubes (CNTs) stand out for their exceptional electrical, thermal, and mechanical attributes, making them highly promising materials for cutting-edge, lightweight, and flexible thermoelectric applications. However, realizing the full potential of advanced thermoelectric CNTs requires precise management of their electrical and thermal characteristics. This study, through interface optimization, demonstrates the feasibility of reducing the thermal conductivity while preserving robust electrical conductivity in single-walled CNT films. Our findings reveal that blending two functionalized CNTs offers a versatile method of tailoring the structural and electronic properties of CNT films. Moreover, the modified interface exerts a substantial influence over thermal and electrical transfer, effectively suppressing heat dissipation and facilitating thermoelectric power generation within CNT films. As a result, we have successfully produced both p- and n-type thermoelectric CNTs, attaining impressive power factors of 507 and 171 μW/mK 2 at room temperature, respectively. These results provide valuable insights into the fabrication of high-performance thermoelectric CNT films.

Doping or ion substitution is often used as an effective strategy to improve photocatalytic activities of several semiconductors. Most frequently, the dopants provide extra states to increase light absorption, alter the electronic structure, or lower the carrier recombination. This work focuses on ion substitution in Bi 2 WO 6 , where the dopants modify band-edge potentials of the catalysts. Specifically, we investigate how the electronegativity (EN) of the dopant could be used to tune the band-edge potentials and how such changes influence the photocatalytic mechanism. Compared to Te that has a lower EN, I lowers the band-edge potentials. While substitutions with both ions enhance Rh B photodegradation and benzylamine photooxidation, the modified band potentials of I-doped Bi 2 WO 6 influence the benzylamine photooxidation pathway, resulting in higher selectivity. Additionally, substitution of I 7+ in the Bi 2 WO 6 lattice improves the morphologies, decreases the band-gap energy, and reduces the carrier recombination. As a result, I-doped Bi 2 WO 6 shows almost 3 times higher %conversion while maintaining 100% selectivity in the oxidative coupling of benzylamine. The findings here signify the importance of the choices of dopants on the photocatalytic reactions and would benefit the design of other related materials for such applications.

Although the use of molecular sieves for imine synthesis is a common protocol, there have been no comprehensive studies on heat-drying methods. This can be crucial for reproducibility. It was found that molecular sieve 5A dried at 160 °C for 5 h under vacuum efficiently promoted the condensation of various ketones and amines to afford even relatively bulky ketimines. Several control experiments and analyses revealed that only a small amount of Brønsted acid sites was important for the activity, rather than dehydration ability. Other types of molecular sieves could be utilized for the reaction after treatment with water followed by heat drying. A continuous-flow acetalization reaction of alcohols using the activated molecular sieve 5A was also demonstrated.

Chiral binaphthyldiimine-Ni(II)-catalyzed asymmetric 1,3-dipolar cycloaddition reactions between acyclic carbonyl ylides generated from donor-acceptor oxiranes and aldehydes are reported. Both aromatic and aliphatic aldehydes could be used as dipolarophiles, providing cis -1,3-dioxolanes with high diastereo- and enantioselectivities. On the basis of mechanistic studies, a monomeric chiral Ni(II) complex was hypothesized to act as the active species for the cycloaddition. The high levels of asymmetric induction are satisfactorily explained by a concerted-asynchronous endo Si -face approach of the aldehyde.

The interfacial compatibility between the graphite/carbon black composite counter electrode (Gr/CB CE) and the perovskite layer is a crucial determinant of the performance of the hole-transport-layer-free carbon-based perovskite solar cells, and judicious selection of the Gr/CB CE application method is essential for achieving an optimum contact. In this work, three different types of Gr/CB CEs application methods are investigated: (1) deposition of Gr/CB on the fluorine-doped tin oxide (FTO) substrate, followed by clamping to the perovskite layer, (2) direct deposition of Gr/CB onto the perovskite layer, and (3) deposition of Gr/CB onto the PbI 2 precursor layer, followed by immersion in methylammonium iodide solution for the in situ conversion of PbI 2 to perovskite. The results revealed that Method 3 produced superior Gr/CB-perovskite contacts, resulting in up to 8.81% power conversion efficiency. The devices prepared using Method 3 also exhibited the best stability in the air, retaining 71.1% of their original efficiency after 1600 h of continuous testing. These results demonstrate that Gr/CB CEs can be considered excellent alternatives to the costly noble metals often employed in perovskite solar cells (PSCs) when deposited using a suitable technique., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

We report on the high-pressure synthesis, crystal structure, and magnetic properties of four novel transition-metal oxyhydrides─Ba 2 NaVO 3 H 3 , Ba 2 NaVO 2.4 H 3.6 , Ba 2 NaCrO 2.2 H 3.8 , and Ba 2 NaTiO 3 H 3 ─crystallizing in the double-perovskite structure. Notably, they have a higher hydride content in their anion sites (50%-63%) than known oxyhydrides with perovskite structures do (≤33%). Vanadium and chromium oxyhydrides exhibited Curie-Weiss magnetic susceptibilities with no magnetic ordering down to 2 K, which may be due to geometrical frustration in their face-centered lattices and weak magnetic interactions. Density functional theory calculations revealed that the transition metal-hydride bonding nature of the prepared oxyhydrides is more covalent than that observed for known perovskite oxyhydrides, as evidenced by the shorter bond lengths of the former. Remarkably, our double-perovskite oxyhydrides with a high hydride content may possess a bonding character intermediate between those of known oxyhydrides and hydrides.

Water electrolysis has received much attention in recent years as a means of sustainable H 2 production. However, many challenges remain in obtaining high-purity H 2 and making large-scale production cost-effective. This study provides a strategy for integrating a two-cell water electrolysis system with solar energy storage. In our proposed system, CuO-Cu(OH) 2 /Cu 2 O was used as a redox mediator between oxygen and hydrogen evolution components. The system not only overcame the gas-mixing issue but also showed high gas generation performance. The redox reaction (charge/discharge) of CuO-Cu(OH) 2 /Cu 2 O led to a significant increase (51%) in the initial rate of H 2 production from 111.7 μmol h -1 cm -2 in the dark to 168.9 μmol h -1 cm -2 under solar irradiation. The effects of light on the redox reaction of CuO-Cu(OH) 2 /Cu 2 O during water electrolysis were investigated by in situ X-ray absorption and photoemission spectroscopy. These results suggest that surface oxygen vacancies are created under irradiation and play an important role in increased capacitance and gas generation. These findings provide a new path to direct storage of abundant solar energy and low-cost sustainable hydrogen production., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Metabolism of a single cell, even within the same organization, differs from other cells by orders of magnitude. Single-cell analysis provides key information for early diagnosis of cancer as well as drug screening. Any slight change in the microenvironment may affect the state of a single cell. Timely and effective cell monitoring is conducive to better understand the behavior of single cells. The immediate response of a single cell described in this study is a liquid transfer-based approach for real-time electrochemical detection. The cell was in situ stimulated by continuous flow with glucose, and lactate secreted from the cell would diffuse into the microflow. The microflow was aspirated into the detection channel where lactate was then decomposed by coupled enzyme reactions and detected by an electrode. This work provides a novel approach for detecting lactate response from a single cell by noninvasive measurements, and the position resolution of the microfluidic probe reaches the level of a single cell and permits individual heterogeneity in cells to be explored in the diagnosis and treatment of cancer as well as in many other situations.

β-Li 3 PS 4 is a solid electrolyte with high Li + conductivity, applicable to sulfide-based all-solid-state batteries. While a β-Li 3 PS 4 -synthesized by solid-state reaction forms only in a narrow 300-450 °C temperature range upon heating, β-Li 3 PS 4 is readily available by liquid-phase synthesis through low-temperature thermal decomposition of complexes composed of PS 4 3 - and various organic solvents. However, the conversion mechanism of β-Li 3 PS 4 from these complexes is not yet understood. Herein, we proposed the synthesis mechanism of β-Li 3 PS 4 from Li 3 PS 4 ·acetonitrile (Li 3 PS 4 ·ACN) and Li 3 PS 4 ·1,2-dimethoxyethane (Li 3 PS 4 ·DME), whose structural similarity with β-Li 3 PS 4 would reduce the nucleation barrier for the formation of β-Li 3 PS 4 . Synchrotron X-ray diffraction clarified that both complexes possess similar layered structures consisting of alternating Li 2 PS 4 - and Li + -ACN/DME layers. ACN/DME was removed from these complexes upon heating, and rotation of the PS 4 tetrahedra induced a uniaxial compression to form the β-Li 3 PS 4 framework.

Since the bullfrog H-ferritin L134P mutant in which leucine 134 is replaced with proline was found to exhibit a flexible conformation in the C axis channel, homologous ferritins with the corresponding mutation have often been studied in terms of a mechanism of iron release from the mineral core within the protein cavity. Meanwhile, a ferritin mutant with the flexible channel is an attractive material in developing a method to encapsulate functional molecules larger than mononuclear ions into the protein cavity. This study describes the clathrate with a horse spleen L-ferritin L134P mutant containing Prussian blue (PB) without a frequently used technique, disassembly and reassembly of the protein subunits. The spherical shell of ferritin was confirmed in a TEM image of the clathrate. The produced clathrate (PB@L134P) was soluble in water and reproduced the spectroscopic and electrochemical properties of PB prepared using the conventional method. The catalytic activity for an oxidoreductive reaction with H 3 axis channel, homologous ferritins with the corresponding mutation have often been studied in terms of a mechanism of iron release from the mineral core within the protein cavity. Meanwhile, a ferritin mutant with the flexible channel is an attractive material in developing a method to encapsulate functional molecules larger than mononuclear ions into the protein cavity. This study describes the clathrate with a horse spleen L-ferritin L134P mutant containing Prussian blue (PB) without a frequently used technique, disassembly and reassembly of the protein subunits. The spherical shell of ferritin was confirmed in a TEM image of the clathrate. The produced clathrate (PB@L134P) was soluble in water and reproduced the spectroscopic and electrochemical properties of PB prepared using the conventional method. The catalytic activity for an oxidoreductive reaction with H 2 O 2 , one of the major applications of conventional PB, was also observed for the clathrate. The instability of PB in alkaline solutions, limiting its wide applications in aqueous media, was significantly improved in PB@L134P, showing the protective effect of the protein shell. The method developed here shows that horse spleen L-ferritin L134P is a useful scaffold to produce clathrates of three-dimensional complexes with ferritin.

It is well known that cell can response to various chemical and mechanical stimuli. Therefore, flow pressure variation induced by sample loading and elution should be small enough to ignore the physical impact on cells when we use a Chip-SPE-MS system for cells. However, most existent Chip-SPE-MS systems ignored the pressure alternation because it is extremely difficult to develop a homogeneous-flow-pressure hyphenated module. Herein, we developed an interesting fluidic isolation-assisted homogeneous-flow-pressure Chip-SPE-MS system and demonstrated that it is adequate for online high-throughput determination and quantification of the 25-hydroxyvitamin D 3 (25(OH)D 3 ) biotransformation in different cells. Briefly, the homogeneous ambient flow pressure is achieved by fluidic isolation between the cell culture channel and the SPE column, and an automatic sampling probe could accomplish the sample loading and dispensing to fulfill online pretreatment of the sample. Through this new system, the expression levels of 24,25-dihydroxyvitamin D 3 (24,25(OH) 2 D 3 ) can be determined in real time with a detection limit of 2.54 nM. In addition, the results revealed that 25(OH)D 3 metabolic activity differed significantly between normal L-02 cells and cancerous HepG2 cells. Treatment of L-02 cells with a high dose of 25(OH)D 3 was found to increase significant formation of 24,25(OH) 2 D 3 , but this change was not apparent in HepG2 cells. The presented system promises to be a versatile tool for online accurate molecule biotransformation investigation and drug screening processes.

Light oxygen voltage-sensing (LOV) domains are widely found in photoreceptor proteins of plants, algae, fungi, and bacteria. Structural studies of LOV domains suggest that Phe and Gln residues located in the proximity of the chromophore undergo conformational changes upon illumination; however, the molecular mechanism associated with activation of the effector domain remains to be elucidated. Photozipper (PZ) protein is an N-terminally truncated aureochrome-1 comprising a LOV domain and a basic leucine zipper domain. Blue light (BL) induces PZ dimerization and subsequently increases its affinity for target DNA. In this study, we prepared PZ mutants with substitutions of F298 and Q317 and performed quantitative analyses in dark and light states. Substitutions of Q317 significantly reduced the light-induced changes in PZ affinity for the target DNA, especially in the case of the high affinities observed in the dark state. Upon illumination, all PZ mutants showed increased affinity for the target sequence, which demonstrated a clear correlation with the dimer fraction of each PZ mutant. These results suggest the existence of a conformational equilibrium and that its shift by a synergistic interaction between the chromophore and protein moiety probably enables BL-regulated switching of aureochrome-1.

We present the high-pressure synthesis and crystal structure of a novel titanium hydride complex, BaCa 2 Ti 2 H 14 , with 9-fold coordination. It comprises a unique dinuclear [Ti 2 H 14 ] 6- complex that consists of a pair of Ti 4+ ions each coordinated by nine hydrides in the monocapped square antiprism, distinguished from the known 9-fold coordination in the mononuclear tricapped trigonal prism of [MH 9 ] x - . The dinuclear hydride complex is stabilized by three-center two-electron bonding at the four bridging Ti-H-Ti bonds to compensate for the lack of valence electrons in the Ti 4+ ions. Optical measurements show that BaCa 2 Ti 2 H 14 is a band insulator with a wide band gap of 2.25 eV. Density functional theory calculations reveal that the top of the valence band is dominated by H-1s-derived states, as expected from the 9-fold coordination, which would present a playground for electronic properties such as high- T c superconductivity when doped with hole carriers or under high pressure.

Branched-chain amino acids (BCAAs) are essential amino acids, controlling cellular metabolic processes as signaling molecules; therefore, utilization of intracellular BCAAs may be regulated by the availability of nutrients in the environment. However, spatial and temporal regulation of intracellular BCAA concentration in response to environmental conditions has been unclear due to the lack of suitable methods for measuring BCAA concentrations inside single living cells. Here, we developed a Förster resonance energy transfer (FRET)-based genetically encoded biosensor for BCAAs, termed optical biosensor for leucine-isoleucine-valine (OLIVe). The biosensor showed approximately 2-fold changes in FRET values corresponding to BCAA concentrations. Importantly, FRET signals from HeLa cells expressing OLIVe in the cytoplasm and nucleus correlated with bulk intracellular BCAA concentrations determined from populations of cells by a biochemical method, and were decreased by knockdown of L-type amino acid transporter 1 (LAT1), a transporter for BCAAs, indicating that OLIVe can reliably report intracellular BCAA concentrations inside single living cells. We also succeeded in imaging BCAA concentrations in the mitochondria using mitochondria-targeted OLIVe. Using the BCAA imaging technique, we found apparently correlated concentrations between the cytoplasm and the mitochondria. We also found that extracellular non-BCAA amino acids affected intracellular BCAA concentrations. Of these amino acids, extracellular glutamine markedly increased intracellular BCAA concentrations in a LAT1-dependent manner. Unexpectedly, extracellular pyruvate was also found to have significant positive effects on maintaining intracellular BCAA concentrations, suggesting that the cells have pyruvate-dependent systems to import BCAAs and/or to regulate BCAA metabolism.

The microwell plate/microtiter plate is among the most widely used tools in immune assays. In this paper, we report on a sensitive method for enhancing fluorescence emission detection by simply adding several droplets of an immiscible organic compound into the microwells before detection. To prove the concept, human IgA was determined on a microwell plate using this droplet enhanced fluorescence (DEF) detection method. An obvious enhancement in fluorescence was observed. The detection limit (LOD) was about 1/20 times and the sensitivity was 4 times greater than that without droplets. To prove the use of the method for disease diagnosis, the IgG of measles in human plasma was determined using the proposed DEF method. A LOD of around 1/5 times and a sensitivity of 4 times the DEF were easily achieved compared to ELISA with a conventional fluorescence detection.

Transition-metal dichalcogenides in the 1T phase have been a subject of increasing interest, which is partly due to their fascinating physical properties and partly to their potential applications in the next generation of electronic devices, including supercapacitors, electrocatalytic hydrogen evolution, and phase-transition memories. The primary method for obtaining 1T WS 2 or MoS 2 has been using ion intercalation in combination with solution-based exfoliation. The resulting flakes are small in size and tend to aggregate upon deposition, forming an intercalant-TMD complex with small 1T and 1T' patches embedded in the 2H matrix. Existing growth methods have, however, produced WS 2 or MoS 2 solely in the 2H phase. Here, we have refined the growth approach to obtain monolayer 1T WS 2 up to 80 μm in size based on chemical vapor deposition. With the aid of synergistic catalysts (iron oxide and sodium chloride), 1T WS 2 can nucleate in the infant stage of the growth, forming special butterfly-like single crystals with the 1T phase in one wing and the 2H phase in the other. Distinctive types of phase boundaries are discovered at the 1T-2H interface. The 1T structure thus grown is thermodynamically stable over time and even persists at a high temperature above 800 °C, allowing for a stepwise edge epitaxy of lateral 1T heterostructures. Atomic images show that the 1T WS 2 -MoS 2 heterojunction features a coherent and defectless interface with a sharp atomic transition. The stable 1T phase represents a missing piece of the puzzle in the research of atomic thin van der Waals crystals, and our growth approach provides an accessible way of filling this gap.

Light-induced CO release from newly synthesized N,C,S-pincer iron(III) carbonyl complexes with two phosphorus ligands- trans-[Fe(L-κ 3 N,C,S)(CO)(PR 2 R') 2 ]PF 6 ([1]PF 6 , R = Me, R' = Ph; [2]PF 6 , R = R' = Me; [3]PF 6 , R = R' = OEt)-were investigated. All the iron(III) carbonyl complexes were stable in solution and showed light-inducible CO release under ambient conditions. Studies on the wavelength dependence of photoreaction revealed that the phosphite complex [3]PF 6 exhibited the most extended photosensitivity including all visible and a part of near-IR light (390-800 nm wavelengths). The phosphine complexes [1]PF 6 and [2]PF 6 showed sensitivity to only the higher-energy region of visible light (390-450 nm). Quantum-chemical calculations and spectroscopic data suggested that all complexes [1]PF 6 -[3]PF 6 have dπ-dπ excitation modes to depopulate Fe-C(carbonyl) bonding and potentially induce the CO release by irradiation of light in the near-IR region, although moderately weakened Fe-C(carbonyl) bonding due to stronger π-backbonding by the phosphite ligand rendered the excitation effective on the CO release exclusively in [3]PF 6 .

Manipulation of light transmission/absorbance and reflection/emission has a great significance in smart windows and displaying media like liquid crystal. Here, we report the usage of an external electric field to reversibly switch the molecular spectra of a model molecule on the basis of its interaction with an electroresponsible polymer brush. Both the UV-vis absorbance spectrum and the fluorescence emission spectrum of the model molecule were confirmed to be electroswitchable. The electroswitchable spectra were experimentally demonstrated to be induced by the electroswitchable statuses of medium anionic poly-allyloxy hydroxypropyl sulfonate (poly-AHPS) brush. Insightfully, the molecular aggregated status of model proflavine molecules could be electrically controlled via the electroresponsible poly-AHPS brushes and then the molecular spectra of the model proflavine molecule also could be electrically and controllably shifted. The success in the manipulation of molecular spectra opens up a wide range of applications not only for displaying but also for nonlinear optics, in vivo imaging, sensors, and environmental inspection.

We report on the development of a novel and flexible online digital polymerase chain reaction (dPCR) system. The system was composed of three parts: an inkjet for generating the droplets, a coiled fused-silica capillary for thermal cycling, and a laser-induced fluorescence detector (LIFD) for positive droplet counting. Upon inkjet printing, monodisperse droplets were continuously generated in the oil phase and then introduced into the capillary in the form of a stable dispersion. The droplets containing one or zero molecules of target DNA passed through the helical capillary that was attached to a cylindrical thermal cycler for PCR amplification, resulting in the generation of fluorescence for the DNA-positive droplet. After 36 PCR cycles, the fluorescence signal intensity was detected by laser-induced fluorescence located at the downstream of the capillary, followed by a positive/negative counting. The present system was successfully applied to the absolute quantification of the HPV sequence in Caski cells with dynamic ranges spanning 4 orders of magnitude.

This study describes a method to investigate the separation of cells by capillary electrophoresis (CE) coupled with inkjet printing system. The results validated the feasibility of inkjet printing for mammalian cells to achieve the drop-on-demand and convenient sampling into capillary then zone electrophoresis was applied to separate different cells according to their electrophoretic mobility, finally the peak signal were measured by UV detector. Linear relationship between the peak area and the droplet number was obtained within the range of 25-400 drops (R 2 = 0.996) at a fixed cell concentration 10 6 /mL, indicating that this system could be used for rapid and accurate quantification of cells.

The C 2 -symmetric tetralin-fused 1,4-diiodo-1,3-butadiene derivatives, (Z,Z)-2,3-di(1-iodoalkylidene)tetralin 1a-c, are atropisomeric and can be resolved into the two persistent axially chiral enantiomers by HPLC on a chiral stationary phase. The enantiomerically pure compounds can serve as chiral organocatalysts for dearomatizing spirolactonization to show good performance in up to 73% ee.

Stable 2-(trimethylsilyl)phenyl trimethylsilyl ethers, readily obtained from the corresponding halogenated phenols in two steps, were identified as novel benzyne precursors. These species were converted to benzynes by a domino reaction of O-desilylation, O-nonaflylation, and β-elimination under mild conditions using nonafluorobutanesulfonyl fluoride (NfF) and tetrabutylammonium triphenyldifluorosilicate (TBAT). The generated benzynes were trapped by various arynophiles to afford a wide variety of benzo-fused heterocycles.

Probe electrospray ionization (PESI) is a recently developed ionization technique that enables the direct detection of endogenous compounds like metabolites without sample preparation. In this study, we have demonstrated the first combination use of PESI with triple quadrupole tandem mass spectrometry (MS/MS), which was then applied to intact endogenous metabolite analysis of mice liver, achieving detection of 26 metabolites including amino acids, organic acids, and sugars. To investigate its practicality, metabolic profiles of control and CCl4-induced acute hepatic injury mouse model were measured by the developed method. Results showed clear separation of the two groups in score plots of principal component analysis and identified taurine as the primary contributor to group separation. The results were further validated by the established gas chromatography/MS/MS method, demonstrating the present method's usefulness. In addition, we preliminarily applied the method to real-time analysis of an intact liver of a living mouse. We successfully achieved monitoring of the real-time changes of two tricarboxylic acid cycle intermediates, α-ketoglutaric acid and fumaric acid, in the liver immediately after pyruvic acid injection via a cannulated tube to the portal vein. The present method achieved an intact analysis of metabolites in liver without sample preparation, and it also demonstrates future possibility to establish in vivo real-time metabolome analysis of living animals by PESI/MS/MS.

We previously reported that Bacillus amyloliquefaciens biocontrol strain SD-32 produces powerful antifungal lipopeptides, C17 bacillomycin D homologues. In the course of the investigation we found that the antifungal activity of the culture supernatant of this bacterium was not ascribed exclusively to bacillomycin D. We attempted to identify metabolites other than bacillomycin D to gain insight into the mechanism for the biocontrol by this bacterium. After purifying the fractions of the culture supernatant exhibiting synergistic activity with bacillomycin D, we isolated two new cyclic lipodepsipeptides, anteiso-C13 and iso-C13 [Ile(7)]surfactins, together with three known [Ile(7)]surfactins. Interestingly, [Ile(7)]surfactins showed synergistic activities with bacillomycin D to gray mold disease on cucumber leaves but not to Botrytis cinerea itself in vitro, suggesting that the synergistic effects might be on infection processes of the fungus. Actually, we observed that they did not show synergistic actions on conidial germination or mycelial growth of B. cinerea on the leaves.

In this work, we report an ultrasensitive hydrogen (H2) sensor based on tungsten trioxide (WO3) nanorods decorated with platinum (Pt) nanoparticles. WO3 nanorods were fabricated by dc magnetron sputtering with a glancing angle deposition (GLAD) technique, and decorations of Pt nanoparticles were performed by normal dc sputtering on WO3 nanorods with varying deposition time from 2.5 to 15 s. Crystal structures, morphologies, and chemical information on Pt-decorated WO3 nanorods were characterized by grazing-incident X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and photoelectron spectroscopy, respectively. The effect of the Pt nanoparticles on the H2-sensing performance of WO3 nanorods was investigated over a low concentration range of 150-3000 ppm of H2 at 150-350 °C working temperatures. The results showed that the H2 response greatly increased with increasing Pt-deposition time up to 10 s but then substantially deteriorated as the deposition time increased further. The optimally decorated Pt-WO3 nanorod sensor exhibited an ultrahigh H2 response from 1530 and 214,000 to 150 and 3000 ppm of H2, respectively, at 200 °C. The outstanding gas-sensing properties may be attributed to the excellent dispersion of fine Pt nanoparticles on WO3 nanorods having a very large effective surface area, leading to highly effective spillover of molecular hydrogen through Pt nanoparticles onto the WO3 nanorod surface.

Both AB diblock and ABA triblock copolymers consisting of poly(L-lactide) (PLLA: A) and poly(ethylene glycol) (PEG: B) were deposited on a silicon surface on which poly(D-lactide) (PDLA) had been preimmobilized. The deposit of the diblock copolymer (PLLA-PEG) formed band structures similar to those observed when the same copolymer was directly deposited on the silicon surface. In contrast, the deposit of the triblock copolymer (PLLA-PEG-PLLA) formed many particulates scattering over the surface. When the PLLA-PEG deposit was subjected to water-soaking, the original band morphology was completely replaced by the particulate morphology that was identical to that of the PLLA-PEG-PLLA deposit. Their FT-IR analyses revealed that both copolymers had been bound through the stereocomplex (sc) formation between the preimmobilized PDLA chains and the PLLA blocks of the copolymers. Grazing-incidence small-angle X-ray scattering (GISAXS) also supported these surface morphologies. It was therefore evident that hydrophilic PEG chains can be immobilized on the PDLA-preimmobilized surface by the sc formation.

Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) is a powerful technique for visualizing the distribution of a wide range of biomolecules within tissue sections. However, methodology for visualizing a bioactive ellagitannin has not yet been established. This paper presents a novel in situ label-free MALDI-MSI technique for visualizing the distribution of strictinin, a bioactive ellagitannin found in green tea, within mammalian kidney after oral dosing. Among nine representative matrix candidates, 1,5-diaminonaphthalene (1,5-DAN), harmane, and ferulic acid showed higher sensitivity to strictinin spotted onto a MALDI sample plate. Of these, 1,5-DAN enables visualization of a two-dimensional image of strictinin directly spotted on mouse kidney sections with the highest sensitivity. Furthermore, 1,5-DAN-based MALDI-MSI could detect the unique distribution of orally dosed strictinin within kidney sections. This in situ label-free imaging technique will contribute to the localization analysis of strictinin and its biological mechanisms.

Two new cyclic lipopeptides (3 and 4) were isolated from the culture filtrate of Bacillus amyloliquefaciens strain SD-32, together with two known metabolites, iso-C15 and iso-C16 bacillomycin D (1 and 2). Spectroscopic and chemical analyses identified the structures of the new compounds 3 and 4 as anteiso-C17 bacillomycin D, cyclic (l-Asn-d-Tyr-d-Asn-l-Pro-l-Glu-d-Ser-l-Thr-3-amino-14-methylhexadecanoic acid) and iso-C17 bacillomycin D, cyclic (l-Asn-d-Tyr-d-Asn-l-Pro-l-Glu-d-Ser-l-Thr-3-amino-15-methylhexadecanoic acid), respectively. The absolute configuration of C-3 in the β-amino fatty acid was determined to be R on the basis of the CD spectrum of its dinitrophenyl-p-methoxyaniline derivative. The activities of compounds 1-4 were evaluated against 13 plant pathogens: the activities of anteiso- and iso-C17 bacillomycin D (3 and 4) were almost the same and stronger than those of iso-C15 and iso-C16 bacillomycin D (1 and 2); iso-C15 bacillomycin D (1) was weakest. Compounds 2-4 inhibited the growth of all fungi tested; however, Pythium aphanidermatum was not inhibited at all by any of the compounds. Furthermore, compounds 1-4 at concentrations of 80, 40, 30, and 30 μM, respectively, inhibited completely the Botrytis cinerea infection in cucumber leaf.

Hydroxyl radical (OH) is an important oxidant in atmospheric aqueous phases such as cloud and fog drops and water-containing aerosol particles. We find that numerical models nearly always overestimate aqueous hydroxyl radical concentrations because they overpredict its rate of formation and, more significantly, underpredict its sinks. To address this latter point, we examined OH sinks in atmospheric drops and aqueous particles using both new samples and an analysis of published data. Although the molecular composition of organic carbon, the dominant sink of OH, is extremely complex and poorly constrained, this sink behaves very similarly in different atmospheric waters and even in surface waters. Thus, the sink for aqueous OH can be estimated as the concentration of dissolved organic carbon multiplied by a general scavenging rate constant [kC,OH = (3.8 ± 1.9) × 10(8) L (mol C)(-1) s(-1)], a simple process that should significantly improve estimates of OH concentrations in atmospheric drops and aqueous particles.

We report a novel chemiluminescence diagnosis system for high-throughput human IgA detection by inkjet nanoinjection on a multicapillary glass plate. As proof-of-concept, microhole-based polydimethylsiloxane (PDMS) sheets were aligned on a multicapillary glass plate to form a microwell array as microreactors for enzyme-linked immunosorbent assay (ELISA). The multicapillary glass plate was utilized as a switch that controlled the holding/passing of the solution. Further, anti-IgA-labeled polystyrene (PS) microbeads was assembled into the microwell array, and an inkjet nanoinjection was specially used to distribute the sample and reagent solution for chemiluminescence ELISA, enabling high-throughput detection of human IgA. As a result, the performance of human IgA tests revealed a wider range for the calibration curve and a lower limit of detection (LOD) of 0.1 ng mL(-1) than the ELISA by a standard 96-well plate. The analysis time and reagent consumption were significantly decreased. The IgA concentrations in saliva samples were determined after 10000-fold dilution by the developed ELISA system showing comparable results by conventional immune assay with 96-wells. Thus, we believe that the inkjet nanoinjection for high-throughput chemiluminescence immunoassay on a multicapillary glass plate will be promising in disease diagnosis.

The role the axial methionine plays in the conformational properties and thermostability of the heme active site has been investigated with the help of site-specific mutations at the axial Met69 position with His (M69H) and Ala (M69A) in thermostable cytochrome c(552) from Thermus thermophilus. Detailed circular dichroism, direct electrochemistry, and other spectroscopic studies have been employed to investigate the thermally induced and GdnHCl-induced unfolding properties of the heme active site of the wild type and the mutants of cytochrome c(552). We observed an unusually high thermodynamic and thermal stability of the M69A mutant compared to that of wild-type cytochrome c(552). However, the M69H mutant exhibited a slightly lower unfolding free energy compared to that of the wild-type protein. The high conformational stability of the M69A mutant was attributed to the presence of residual structure in the unfolded state as well as to the altered conformation in the folded state of this mutant of cytochrome c(552). This study thus supports the view that apart from the folded state, the unfolded state of a protein may also make a significant contribution to the stability of a protein.

A novel, highly accurate sample injection system for capillary electrophoresis (CE) was developed based on an inkjet microchip capable of reproducing exact introduction volumes at the picoliter level. The difficulty in analyte discrimination using electrokinetic injection was also overcome using this injection method. The injection system consisted of an XY stage, an inkjet droplet ejection microchip, and a reservoir with a plug-in septum. To evaluate the precision of the system, a mixture of NBD-labeled amino acids consisting of Gly, L-Phe, L-Asp, and L-Ser was separated, and the performance was compared with that of traditional hydrodynamic and electrokinetic injection methods. The results demonstrated that the introduced volume highly relied on the number of droplets with low relative standard derivation (RSD) and good linear correction coefficient in the proposed injection method. In addition, a urine sample was analyzed via CE coupled with the inkjet injection system for the detection of the amino acid taurine. The concentration of urinary taurine was determined to be 2.42 ± 0.08 μM (confidence level, 95%; RSD, 1.05%; n = 4) with a recovery of 98.92-109.54% (n = 3). These results demonstrate the inkjet injection system we developed has the potential to revolutionize capillary electrophoretic separation in practical and commercial applications that require an automated accurate injection system.

The facile replacement of heme c in cytochromes c with non-natural prosthetic groups has been difficult to achieve due to two thioether linkages between cysteine residues and the heme. Fee et al. demonstrated that cytochrome c(552) from Thermus thermophilus, overproduced in the cytosol of E. coli, has a covalent linkage cleavable by heat between the heme and Cys11, as well as possessing the thioether linkage with Cys14 [Fee, J. A. (2004) Biochemistry 43, 12162-12176]. Prompted by this result, we prepared a C14A mutant, anticipating that the heme species in the mutant was bound to the polypeptide solely through the thermally cleavable linkage; therefore, the removal of the heme would be feasible after heating the protein. Contrary to this expectation, C14A immediately after purification (as-purified C14A) possessed no covalent linkage. An attempt to extract the heme using a conventional acid-butanone method was unsuccessful due to rapid linkage formation between the heme and polypeptide. Spectroscopic analyses suggested that the as-purified C14A possessed a heme b derivative where one of two peripheral vinyl groups had been replaced with a group containing a reactive carbonyl. A reaction of the as-purified C14A with [BH(3)CN](-) blocked the linkage formation on the carbonyl group, allowing a quantitative yield of heme-free apo-C14A. Reconstitution of apo-C14A was achieved with ferric and ferrous heme b and zinc protoporphyrin. All reconstituted C14As showed spontaneous covalent linkage formation. We propose that C14A is a potential source for the facile production of an artificial cytochrome c, containing a non-natural prosthetic group.

Poly(D-lactide)s (PDLA) having an end group of trimethoxysilyl (P(x)-Si-(OMe)(3)) or monoethoxydimethylsilyl (P(x)-Si-OEt) group were synthesized to immobilize macromolecular chains of polylactide onto a flat silicon surface by the "grafting onto" mechanism. Both the end-functional PDLAs were efficiently immobilized on the flat surface of silicon wafers to create different nano-ordered structures. The P(x)-Si-OEt having the monofunctional siloxyl group formed a homogeneous dot morphology consisting of homogeneously dispersed particles of 20-30 nm in diameter while the P(x)-Si-(OMe)(3) having the trifunctional siloxyl group formed a heterogeneous morphology consisting of both spots and fibrous strands. The former homogeneous morphology was attributed to the lack of the intermolecular cross-linking reaction that was evident in P(x)-Si-(OMe)(3).

A novel polymer blend system consisting of poly(l-lactide) (PLLA) and a thermotropic liquid crystalline polymer (LCP: an aromatic polyester comprising poly(4-hydroxybenzoate) sequences) was investigated in the presence and absence of a polycabodiimide (PCD). Scanning electron micrographs of the injection-molded polymer blends revealed the formation of fibrous structure of LCP in the PLLA matrix, supporting the efficient toughening. In particular, the LCP fibrils became semimicrometer in diameter in the presence of PCD with which both PLLA and LCP had reacted during the melt blending to form their block and graft copolymers working as compatibilizer. The blend specimens containing LCP in 20-30 wt % were found to hold high dynamic storage-moduli (E') at high temperature. In addition, the E' value of the specimens containing 30 wt % of LCP reached 10.7 GPa at room temperature, being significantly higher than that of PLLA.

Stinkbug is a major rice plant pest in Asia. The extract of the culture filtrate of a fungus isolated from a green foxtail, Setaria viridis (L.) Beauv., was found to have a repellent effect on the white-spotted stinkbug, Eysarcoris ventralis (Westwood). The active principle was purified and isolated, and identified as 3-(4-methylfuran-3-yl)propan-1-ol (1) on the basis of spectroscopic data. Four acyl derivatives were prepared from 1 and assessed for repellent effect on the stinkbug; the acetyl derivative 2 was most effective.

Photoinduced electron transfer (ET) in zinc-substituted cytochrome c (Zn-cyt c) has been utilized in many studies on the long-range ET in protein. Attempting to understand its ET mechanism in terms of electronic structure of the molecule, we have calculated an all-electron wave function for the ground-state of Zn-cyt c on the basis of density functional theory (DFT). The four molecular orbitals (MOs) responsible for excitation by UV-vis light (Gouterman's 4-orbitals) are assigned on the basis of the excited states of chromophore model for Zn-porphine complex calculated with the time-dependent DFT method. ET rates between each Gouterman's 4-orbitals and other MOs were estimated using Fermi's golden rule. It appeared that the two occupied MOs of the 4-orbitals show exclusively higher ET rate from/to particular MOs that localize on outermost amino acid residues (Lys 7 or Asn 54), respectively, whereas ET rates involving the two unoccupied MOs of the 4-orbitals are much slower. These results imply that the intramolecular ET in photoexcited Zn-cyt c is governed by the hole transfer through occupied MOs. The couplings of MOs between zinc porphyrin core and specific amino acid residues on the protein surface have been demonstrated in Zn-cyt c immobilized on an Au electrode via carboxylic acid group-terminated self-assembled monolayer. The Zn-cyt c-modified electrode showed photocurrents responsible for photoillumination. The action spectrum of the photocurrent was identical with the absorption spectrum of Zn-cyt c, indicating photoinduced electron conduction via occupied MOs. The voltage dependence of the photocurrent appeared to be linear and bidirectional like a photoconductor, which strongly supports the intramolecular ET mechanism in Zn-cyt c proposed on the basis of the theoretical calculations.

Boron complexes surrounded with organic cages were controlled precisely by a remote atom placed at the bottom of the cage. A replacement of the bottom tether atom (carbon or silicon) changed the characteristics (kinetic and thermodynamic factors) of boron complexes by geometric effects. A theoretical study shows that the bottom atoms also control eigenvalues of MO. This cage complex will provide a systematic template for fine-tuning of metal complexes to create various properties.

A series of myoglobin mutants, in which distal sites are modified by site-directed mutagenesis, are able to catalyze peroxidase, catalase, and P450 reactions even though their proximal histidine ligands are intact. More importantly, reactions of P450, catalase, and peroxidase substrates and compound I of myoglobin mutants can be observed spectroscopically. Thus, detailed oxidation mechanisms were examined. On the basis of these results, we suggest that the different reactivities of P450, catalase, and peroxidase are mainly caused by their active site structures, but not the axial ligand. We have also prepared compound 0 under physiological conditions by employing a mutant of cytochrome c 552. Compound 0 is not able to oxidize ascorbic acid.

apo-Myoglobin (apo-Mb) was reconstituted with three copper complexes: CuII(Sal-Phe) (1; Sal-Phe = N-salicylidene-L-phenylalanato), CuII(Sal-Leu) (2; Sal-Leu = N-salicylidene-L-leucinato), and CuII(Sal-Ala) (3; Sal-Ala = N-salicylidene-L-alanato). The crystal structures of 1.apo-Mb (1.65 Angstrom resolution) and 2.apo-Mb (1.8 Angstrom resolution) show that the coordination geometry around the CuII atom in apo-Mb is distorted square-planar with tridentate Sal-X and a Nepsilon atom of His64 in the apo-Mb cavity and the plane of these copper complexes is perpendicular to that of heme. These results suggest that the apo-Mb cavity can hold metal complexes with various coordination geometries.