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Abstract: Recent studies suggest that the behavioral effects of chronic antidepressant treatment are mediated by stimulation of hippocampal neuronal plasticity and neurogenesis. The present study was designed to examine the effects of 3,6′-disinapoyl sucrose (DISS), a bioactive component of Polygala tenuifolia Willd, on the expressions of four plasticity-associated genes: cell adhesion molecule L1 (CAM-L1), laminin, cAMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in hippocampus, all of which are involved in neuronal plasticity and neurite outgrowth. We confirmed that chronic stress in rats caused a reduction in sensitivity to reward (sucrose consumption) and a decrease in mRNA levels of CAM-L1, laminin, and BDNF, together with a decrease in protein levels of phosphorylated CREB and BDNF. Repeated administration of DISS for 21 days at doses of 5, 10 and 20mg/kg reversed stress-induced alterations in sucrose consumption and these target mRNA and protein levels. In conclusion, increased expressions in the hippocampus of three noradrenergic-regulated plasticity genes and one neurotrophic factor may be one of the molecular and cellular mechanisms underlying the antidepressant action of DISS in chronic mild stress (CMS) rats. [Copyright &y& Elsevier]

During meiosis, homologues become juxtaposed and synapsed along their entire length. Mutations in the cohesin complex disrupt not only sister chromatid cohesion but also homologue pairing and synaptohemal complex formation. In this study, we report that Pds5, a cohesin-associated protein known to regulate sister chromatid cohesion, is required for homologue pairing and synapsis in budding yeast. Pds5 colocalizes with cohesin along the length of meiotic chromosomes. In the absence of Pds5, the meiotic cohesin subunit Rec8 remains bound to chromosomes with only minor defects in sister chromatid cohesion, but sister chromatids synapse instead of homologues. Double-strand breaks (DSBs) are formed but are not repaired efficiently. In addition, meiotic chromosomes undergo hypercondensation. When the mitotic cohesin subunit Mcd1 is substituted for Rec8 in Pds5-depleted cells, chromosomes still hypercondense, but synapsis of sister chromatids is abolished. These data suggest that Pds5 modulates the Rec8 activity to facilitate chromosome morphological changes required for homologue synapsis, DSB repair, and meiotic chromosome segregation. [ABSTRACT FROM AUTHOR]

One of the most important challenges of molecular electronics is to enable systematic fabrication of molecular functional components on well-characterized solid-state substrates in a controlled manner. Recently, experimental techniques were developed to achieve such fabrication where lines of r-stacked ethylbenzene molecules are induced to self-assemble on an H-terminated Si(100) surface at precise locations and along precise directions. In this work, we theoretically analyze charge transport properties of these ethylbenzene wires using a state-of-the-art first-principles technique where density functional theory (DFT) is used within the nonequilibrium Green's function formalism (NEGF). Our device model consists of ethylbenzene stacks bonded to an H-terminated Si(1 00) surface and bridging two metal leads. The electron transmission spectrum and its associated scattering states as well as the resistance of the molecular wire are determined by the self-consistent NEGF-DFT formalism. The transmission spectrum has a resonance nature for energies around the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the ethylbenzene wires. However, near the Fermi level of the device, which sits inside the HOMO-LUMO gap, the Si substrate is found to play an important role in providing additional pathways for conduction. It has emerged that, within our model system, the transmission peak nearest to the Fermi level corresponds to transport through the Si substrate and not the π-stacked molecular line. The low-bias resistance R is found to increase exponentially with the length of the molecular line n, as R ∼eβn, indicating a tunneling behavior in conduction. We further found that the exponential scaling has two regimes characterized by two different scaling parameters β: a high value for conduction through the molecular stack in short lines and a lower value for conduction through the substrate in longer lines. Our results suggest that when the conduction of molecular wires bonded to semiconductor substrates is theoretically analyzed, conduction pathways through the substrate need to be taken into account. [ABSTRACT FROM AUTHOR]

The inheritance of mitochondrial genes and genomes are uniparental in most sexual eukaryotes. This pattern of inheritance makes mitochondrial genomes in natural populations effectively clonal. Here, we examined the mitochondrial population genetics of the emerging human pathogenic fungus Cryptococcus gattii. The DNA sequences for five mitochondrial DNA fragments were obtained from each of 50 isolates belonging to two evolutionary divergent lineages, VGI and VGII. Our analyses revealed a greater sequence diversity within VGI than that within VGII, consistent with observations of the nuclear genes. The combined analyses of all five gene fragments indicated significant divergence between VGI and VGII. However, the five individual genealogies showed different relationships among the isolates, consistent with recent hybridization and mitochondrial gene transfer between the two lineages. Population genetic analyses of the multilocus data identified evidence for predominantly clonal mitochondrial population structures within both lineages. Interestingly, there were clear signatures of recombination among mitochondrial genes within the VGII lineage. Our analyses suggest historical mitochondrial genome divergence within C. gattii, but there is evidence for recent hybridization and recombination in the mitochondrial genome of this important human yeast pathogen. [ABSTRACT FROM AUTHOR]

G-rich sequences with the potential for quadruplex formation are common in genomic DNA. Considering that the biological functions of G-quadruplexes may well depend on their structures, the development of a sensitive structural probe for distinguishing different types of quadruplexes has received great attention. Crystal violet (CV) is a triphenylmethane dye, which can stack onto the two external G-quartets of a G-quadruplex. The ability of CV to discriminate G-quadruplexes from duplex and single-stranded DNAs has been reported by us. Herein, the ability of CV to discriminate parallel from antiparallel structures of a G-quadruplex was studied. The binding of CV to an antiparallel G-quadruplex can make its fluorescence intensity increase to a high level because of the protection of bound CV from the solvent by quadruplex end loops. The presence of side loops in parallel G-quadruplexes cannot provide bound CV such protection, causing the fluorescence intensity of CV/G-quadruplex mixture to be obviously weaker when the G-quadruplex adopts a parallel structure than that when the G-quadruplex adopts an antiparallel structure. Therefore, CV can be developed as a sensitive fluorescent biosensor for the discrimination of antiparallel G-quadruplexes from parallel G-quadruplexes and for monitoring the structural interconversion of G-quadruplexes. In addition, considering that some G-rich DNA sequences can adopt different G-quadruplex structures under Na+ or K+ ion conditions, a novel, cheap and simple K+ ion detection method was developed. This method displays a high K+ ion selectivity against Na+ ion, the change of 200 mM in Na+ ion concentration only causes a similar fluorescent signal change to 0.3 mM K+ ion. [ABSTRACT FROM AUTHOR]

Grain boundary character distribution (GBCD) and triple junction character distribution (TJCD) in a 304 stainless steel cold rolled with the thickness reduction of 6% and then annealed at 1323K for 5 minutes(GBE process) were analyzed by electron back scatter diffraction (EBSD). The intergranular corrosion (IGC) resistance of various triple junctions and grain boundaries were evaluated after sensitization treatment at 1073K for 30 minutes. The results showed special TJ containing 2 or 3 CSL boundaries exhibit higher resistance to IGC than other TJs. In addition, the {411} and {221} symmetrical tilt grain boundaries (STGBs) are more resistant to intergranular corrosion for Σ9 boundaries. [ABSTRACT FROM AUTHOR]

Large area layered ultrathin films have attracted much attention in recent years, as they have ordered structure, unique properties and potential applications in various areas, such as transportation, separation and catalysis. Herein, we reported the successful preparation of large area layered ultrathin films of a bola-type amphiphilic molecule, perfluorodecanedioic acid (PFDDA) at the liquid/liquid interface in the absence or presence of metal ions. It was found that the ultrathin thin film of PFDDA/Zn(II) has a hexagonal closed packed crystal structure with the crystal parameters of a = 0.302 and c = 1.9 nm. The formation of the film was attributed to the weaker intermolecular interactions, the restriction of the interfacial phase, and the epitaxial growth. However, dodecanedioic acid (DDDA) and docosanedioic acid (DCDA) formed ultrathin nanosheets instead of large area films through this approach, reflecting different self-assembly behavior of the perfluorocarbon chains and the hydrocarbon chains. Large area layered ultrathin films of a bola-amphiphilic perfluorodecanedioic acid were fabricated at the liquid/liquid interface. [Display omitted] • Large area layered ultrathin films of bola-amphiphilic molecules were fabricated. • The amphiphilic molecule is perfluorodecanedioic acid. • The films were fabricated at the planar liquid/liquid interface. • The fabrication process includes nucleation and 2D epitaxial growth. • Amphiphobic effects, coordination or H-bonds are responsible for the film formation. [ABSTRACT FROM AUTHOR]

Protein phosphorylation plays an important role in many significant cellular processes, and has thus gained tremendous interest in the field of proteomics. The electro-active tyrosine residue, as an important receptor of phosphorylation in proteins, exhibits electro-inactivity after being phosphorylated on the hydroxy group of its aromatic ring. In this study, the electrochemical oxidation of tyrosine on indium tin oxide (ITO) electrodes was catalyzed with an electron mediator Os(bpy)32+(bpy = 2,2′-bipyridine) and was employed as a signal reporter to differentially detect non-phosphorylated and phosphorylated peptides. A short, tyrosine-containing peptide glu-glu-glu-glu-glu-tyr (EY-6) was immobilized on an ITO surface using the layer-by-layer self-assembly method, and was detected by cyclic voltammetry in an Os(bpy)32+solution. The limit of detection was about 0.23 μg mL−1EY-6 in solution. The phosphorylated peptide glu-glu-glu-glu-glu-tyr-OP (EY-6P) did not produce an appreciable oxidation current on the electrode. Surface plasmon resonance measurements revealed that the amount of EY-6 and EY-6P adsorbed on the sensor chip surface was 269 and 378 pg mm−2, respectively. The poly(glu, tyr) (4 : 1) peptide, a protein tyrosine kinase substrate, was also detected by the same approach, with a detection limit of 0.65 μg mL−1. This new approach offers the possibility of label-free and on-chip detection of protein tyrosine kinase activity. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an integrated virtual reality geographic information system (VRGIS) based on computational stereo. In this system, three-dimensional (3D) and 360° panoramic scenes are reconstructed from multiple stereo image pairs acquired with a mobile stereo machine vision system. The spatial coordinates of panoramic scenes are registered to electronic maps to obtain a real scale VRGIS that is capable of efficient retrieval of spatial information and allows for navigation in virtual reality. A software program was implemented for image processing, coordinate transformation, 3D surface model building, data fusion, digital mapping, and database management for the VRGIS. In setting up 3D models for the virtual reality environment, we focused on comparisons of pattern matching algorithms for creating disparity images from stereo pairs, and adopted the graph cut method and the non-parametric local transform method in our system. Following the computation of disparity images, they are transformed into cylindrical coordinates and stitched into a 3D and 360° panoramic scene. In order to allow for virtual reality navigation, the panoramic scene is further cast into 3D triangular surface model for fast texture mapping using memoryless simplification algorithm. The effects of reducing the number of edges in a 3D surface model on computation time and discrepancy from 3D surface model with no edge reduction were also analyzed. Experimental results show that the discrepancy was about 13% when 80% edge reduction was applied to create the approximate 3D surface model. This indicates a significant computational and memory reduction while the computer graphic display of the scene model was still visually satisfactory. Finally, multiple 3D scenes were integrated into a site on the electronic map permitting the user to navigate through location to location in a virtual reality environment. The developed system may serve as a versatile platform in establishing field information for many applications such as precision agriculture, vehicle automation, geographic visualization, archaeology site modelling, etc. [Copyright &y& Elsevier]

Background: Development of Helicobacter pylori vaccine would be a new effective strategy for prevention and treatment of H. pylori infection. Recombinant H. pylori vaccine comprising a single subunit antigen can only induce immune response with limited protection efficiency. In this study, the protective effect of H. pylori multicomponent vaccines consisting of three recombinant subunit antigens was investigated using the Mongolian gerbil model. Materials and methods: Mongolian gerbils were immunized with different formulations of three recombinant H. pylori antigens (UreB, HspA, and HpaA) with two different adjuvants (Al(OH)3, LTR72DITH) by intragastric (i.g.) or intramuscular (i.m.) routes. The protective effects of multicomponent vaccines were assessed after H. pylori challenge in different studies. The specific IgG antibodies in serum were monitored by ELISA, and the mRNA expressions of IL-4 and IFN-γ in spleen tissue were detected by reverse transcribed polymerase chain reaction (RT-PCR). Results: The protective effect against H. pylori challenge in gerbils immunized with three recombinant antigens and LTR72DITH or Al(OH)3 was significantly higher than that in single- or double-antigen vaccine-immunized and control gerbils. Furthermore, the protective effect of the triple-antigen vaccine combined with the LTR72DITH adjuvant (average 86.3%) was significantly greater than that of vaccine combined with the Al(OH)3 adjuvant (average 53.4%). After the first immunization, the anti-UreB/HspA/HpaA serum IgG level in gerbils immunized with triple-antigen vaccine combined with Al(OH)3 was higher than that in gerbils immunized with the vaccine combined with LTR72DITH. Splenic interferon (IFN)-γ and interleukin (IL)-4 transcript levels were significantly increased in LTR72DITH vaccine-immunized gerbils as compared to the Al(OH)3 vaccine group. Moreover, splenic IL-4 mRNA levels were higher than IFN-γ in gerbils immunized with triple-antigen vaccine with either LTR72DITH or Al(OH)3. Conclusions: This study indicated that the recombinant multicomponent vaccine provided effective protection against H. pylori infection as compared to the single-antigen vaccine. This protective immunity would be closely associated with a predominant Th2-type response. [ABSTRACT FROM AUTHOR]

The metal ion dependent decomposition of hydrogen peroxide, the so-called Fenton Reaction, yields hydroxyl radicals that can cause oxidative DNA damage both in vitroand in vivo. We have previously reported a photoelectrochemical sensor for the detection of oxidative DNA damage induced by an Fe2-mediated Fenton Reaction, using a DNA intercalator as a photoelectrochemical signal reporter (Liang, M.; Guo, L.-H. Environ. Sci. Technol. 2007,41, 658).The intercalator binds less to the damaged DNA in the sensor film than the native form, resulting in a reduction in the measured photocurrent. In this report, some mechanistic aspects of the sensor were investigated. It was found that Fe2alone (without the coexistence of H2O2) suppressed the photocurrent of the intercalator bound to the DNA film in a pH-dependent manner. Similar pH dependence was observed for the potential of the tin oxide nanoparticle colloid used in the preparation of the semiconductor electrode, leading to the hypothesis that the metal ion binds to the surface oxide groups on the electrode and quenches the photoelectrochemical response. At pH 3, the quenching effect was reduced substantially to permit the detection of DNA damage by as low as 10 M Fe2and 40 M H2O2, a concentration that is within the physiologically relevant range. It was also found that Fe2ions associated with the DNA in the sensor film and participated in the DNA damage reaction, a mechanism that has been implicated in previous studies on metal carcinogenesis. [ABSTRACT FROM AUTHOR]

For the beam splitter attack strategy against quantum key distribution using two-mode squeezed states, the analytical expression of the optimal beam splitter parameter is provided in this paper by applying the Shannon information theory. The theoretical secret information rate after error correction and privacy amplification is given in terms of the squeezed parameter and channel parameters. The results show that the two-mode squeezed state quantum key distribution is secure against an optimal beam splitter attack. [ABSTRACT FROM AUTHOR]

Abstract: The activity of hypoxia-inducible factors-1α (HIF-1α) is regulated by two types of hydroxylases, prolyl-hydroxylase (PHD) and aspargynyl-hydroxylase factor inhibiting HIF-1α (FIH). Hydroxylation of HIF-1α by PHD and FIH causes proteasomal degradation and transcriptional inhibition of HIF-1α, respectively. Siah ubiquitin ligases regulate the abundance of PHD via targeting for proteasomal degradation. The present study investigated the role of Siah-1 in the regulation of FIH abundance under normoxic conditions. Immunohistochemical analysis of the rat brains revealed that both Siah-1 and FIH were widely distributed in the central nervous system including the cerebral cortex, the hippocampus, the striatum, the olfactory bulb, the putamen, the thalamus, the celleberum, and the brain stem. In the hippocampus, both Siah-1 and FIH predominantly expressed in neurons. Siah-1 and FIH localized mostly in the cytoplasm. In mammalian cells, FIH expression levels were increased in the presence of a proteasomal inhibitor MG132, suggesting that FIH is degraded by the ubiquitin–proteasome system. Immunoprecipitation assay and ubiquitination assay revealed that Siah-1 interacted with, and ubiquitinated FIH. Under normoxic conditions, Siah-1 facilitated degradation of FIH. On the other hand, when endogenous Siah-1 expression was suppressed using siRNA, FIH expression levels were increased, as compared to control. These results suggest that Siah-1 might play a role as a regulator of FIH abundance under normoxic conditions. [Copyright &y& Elsevier]

Glutamate is the major excitatory neurotransmitter in the central nervous system. Its activity is carefully modulated in the synaptic cleft by glutamate transporters. The glial glutamate transporter EAAT2 is the main mediator of glutamate clearance. Reduced EAAT2 function could lead to accumulation of extracellular glutamate, resulting in a form of cell death known as excitotoxicity. In amyotrophic lateral sclerosis and Alzheimer disease, EAAT2 protein levels are significantly decreased in affected areas. EAAT2 mRNA levels, however, remain constant, indicating that alterations in EAAT2 expression are due to disturbances at the post-transcriptional level. In the present study, we found that some EAAT2 transcripts contained 5′-untranslated regions (5′-UTRs) greater than 300 nucleotides. The mRNAs that bear long 5′-UTRs are often regulated at the translational level. We tested this possibility initially in a primary astrocyte line that constantly expressed an EAAT2 transcript containing the 565-nt 5′-UTR and found that translation of this transcript was regulated by many extracellular factors, including corticosterone and retinol. Moreover, many disease-associated insults affected the efficiency of translation of this transcript. Importantly, this translational regulation of EAAT2 occurred in vivo (i.e. both in primary cortical neurons-astrocytes mixed cultures and in mice). These results indicate that expression of EAAT2 protein is highly regulated at the translational level and also suggest that translational regulation may play an important role in the differential EAAT2 protein expression under normal and disease conditions. [ABSTRACT FROM AUTHOR]

In eukaryotic cells, cohesin holds sister chromatids together until they separate into daughter cells during mitosis. We have used chromatin immunoprecipitation coupled with microarray analysis (ChIP chip) to produce a genome-wide description of cohesin binding to meiotic and mitotic chromosomes of Saccharomyces cerevisiae. A computer program, PeakFinder, enables flexible, automated identification and annotation of cohesin binding peaks in ChIP chip data. Cohesin sites are highly conserved in meiosis and mitosis, suggesting that chromosomes share a common underlying structure during different developmental programs. These sites occur with a semiperiodic spacing of 11 kb that correlates with AT content. The number of sites correlates with chromosome size; however, binding to neighboring sites does not appear to be cooperative. We observed a very strong correlation between cohesin sites and regions between convergent transcription units. The apparent incompatibility between transcription and cohesin binding exists in both meiosis and mitosis. Further experiments reveal that transcript elongation into a cohesin-binding site removes cohesin. A negative correlation between cohesin sites and meiotic recombination sites suggests meiotic exchange is sensitive to the chromosome structure provided by cohesin. The genome-wide view of mitotic and meiotic cohesin binding provides an important framework for the exploration of cohesins and cohesion in other genomes. [ABSTRACT FROM AUTHOR]

In the present study, we investigated the role of membrane cholesterol in the function of glutamate transporters. Depletion of membrane cholesterol by methylf-β-cyclodextrin resulted in reduced Na+-dependent glutamate uptake in primary cortical cultures. Glial glutamate transporter EAAT2-mediated uptake was more sensitive to this effect. Cell surface biotinylation and immunostaining experiments revealed that the loss of cholesterol significantly altered the trafficking of EAAT2 to the plasma membrane as well as their membrane distribution. These effects were also observed in neuronal glutamate transporter EAAT3 but to a lesser extent. Furthermore, the treatment of mouse brain plasma membrane vesicles with methyl-β-cyclodextrin resulted in a significant reduction in glutamate uptake, suggesting that cholesterol depletion has a direct effect on the function of the glutamate transporters. Plasma membrane cholesterol is localized within discreet microdomains known as lipid rafts. Analyses of purified lipid raft microdomains revealed that a large portion of total EAAT2 and a minor portion of total EAAT1, EAAT3, and EAAT4 were associated with lipid rafts. Artificial aggregation of lipid rafts in vivo resulted in the formation of larger EAAT2-immunoreactive clusters on the cell surface. The purified lipid raft-associated fractions were capable of Na+-dependent glutamate uptake. Our data suggest that the glutamate transporters, especially EAAT2, are associated with cholesterol-rich lipid raft microdomains of the plasma membrane and that the association with these cholesterol-rich microdomains is important for excitatory amino acid transporter localization and function. [ABSTRACT FROM AUTHOR]

In eukaryotic cells, cohesin holds sister chromatids together until they separate into daughter cells during mitosis. We have used chromatin immunoprecipitation coupled with microarray analysis (ChIP chip) to produce a genome-wide description of cohesin binding to meiotic and mitotic chromosomes of Saccharomyces cerevisiae. A computer program, PeakFinder, enables flexible, automated identification and annotation of cohesin binding peaks in ChIP chip data. Cohesin sites are highly conserved in meiosis and mitosis, suggesting that chromosomes share a common underlying structure during different developmental programs. These sites occur with a semiperiodic spacing of 11 kb that correlates with AT content. The number of sites correlates with chromosome size; however, binding to neighboring sites does not appear to be cooperative. We observed a very strong correlation between cohesin sites and regions between convergent transcription units. The apparent incompatibility between transcription and cohesin binding exists in both meiosis and mitosis. Further experiments reveal that transcript elongation into a cohesin-binding site removes cohesin. A negative correlation between cohesin sites and meiotic recombination sites suggests meiotic exchange is sensitive to the chromosome structure provided by cohesin. The genome-wide view of mitotic and meiotic cohesin binding provides an important framework for the exploration of cohesins and cohesion in other genomes. Chromatin immunoprecipitation reveals that cohesin sites -- those responsible for holding sister chromatids together until they separate into daughter cells -- are conserved in meiosis and mitosis. [ABSTRACT FROM AUTHOR]

The effect of 975 W microwave irradiation on the crystalline structure of isotactic polypropylene (iPP) surface layer in Al/iPP/Al composite was studied by attenuated total reflection Fourier transform infrared (FTIR) and asymmetry diffraction geometry small-angle x-ray diffraction (XRD). The results show that after about 60 min irradiation, the orientated structure and crystallinity of the iPP surface layer are dropped, crystal transformation (α → β) happens. The iterative peak-fit of XRD curves indicates that the reasons for crystal transformations are: the microwave effect causes the increase of the order level of the crystal lattice, the defaults within the β-crystals are, thus, reduced. D[300] (stands for β-form phase) becomes larger, β-form iPP becomes more perfect. With microscopic distortion coefficient ε[300] and the microscopic stress of β-form becomes less attraction, the microscopic stress of the α-form goes up. This crystal transformation is useful for improving the toughness of iPP in electromagnetic shielding materials. [ABSTRACT FROM AUTHOR]

The biomimitic growth of hydroxyapatite (HAp) on the surface of collagen membrane soaked in 1.5× simulate body fluid (SBF) solution was observed in situ by phase-contrast microscopy. The nucleation of HAp was very slow at the initial stage (first 3 days) on the surface of collagen. After an incubation period, the growth of HAp crystals occurred quickly. The negatively charged carboxylate groups of collagen surface are responsible for the deposition of HAp. This deduction was confirmed by the red shifts of stretching vibration band of carboxylate groups of collagen molecules in Fourier transform infrared spectroscopy (FTIR) spectra. The crystallographic structure of HAp/collagen composite was studied by FTIR spectroscopy, X-ray diffraction (XRD) and electron probe microanalyzer (EPM). This composite material of HAp/collagen may be applicable for use as a bone substitute. [Copyright &y& Elsevier]

Eukaryofic DNA topoisomerase I (Top1) is a monomeric protein clamp that functions in DNA replication, transcription, and recombination. Opposable "lip" domains form a salt bridge to complete Top1 protein clamping of duplex DNA. Changes in DNA topology are catalyzed by the formation of a transient phosphotyrosyl linkage between the active-site Tyr-723 and a single DNA strand. Substantial protein domain movements are required for DNA binding, whereas the tight packing of DNA within the covalent Topl-DNA complex necessitates some DNA distortion to allow rotation. To investigate the effects of Topi-clamp closure on enzyme catalysis, molecular modeling was used to design a disulfide bond between residues Gly-365 and 5er-534, to crossiink protein loops more proximal to the active-site tyrosine than the protein loops held by the Lys-369-Glu-497 salt bridge. In reducing environments, Topi-Clamp was catalytically acfive. However, contrary to crosslinking the salt-bridge loops [Carey, J. F., Schultz, S. J., Sission, L., Fazzio, T. G. & Champoux, J. J. (2003) Proc. Natl. Acad. Sci. USA 100, 5640-5645], crosslinking the active-site proximal loops inhibited DNA rotation. Apparently, subtle alterations in Top1 clamp flexibility impact enzyme catalysis in vitro. Yet, the catalytically active Topi-Clamp was cytotoxic, even in the reducing environment of yeast cells. Remarkably, a shift in redox potential in glrlA cells converted the catalytically inactive Top1Y723F mutant clamp into a cellular toxin, which failed to induce an S-phase terminal phenotype. This cytotoxic mechanism is distinct from that of camptothecin chemotherapeutics, which stabilize covalent Topl-DNA complexes, and it suggests that the development of novel therapeutics that promote Topi-clamp closure is possible. [ABSTRACT FROM AUTHOR]

As one of the most promising candidates in wearable energy storage devices, aqueous fibrous zinc metal batteries (AFZMBs) remain limited by some severe challenges, such as short life span and unstable capacity performance, etc. In this work, the stability of AFZMB is extended by fabricating an innovative stratified deposition framework (SDF) anode. The as‐prepared SDF electrode can achieve a stratified deposition of Zn metals from the bottom layer to the top layer due to the different overpotentials and binding energy of Zn deposition. Compared with commercial Zn fibers, this dexterous structure provides enough deposition space for Zn metals between the separator and the electrode, dramatically alleviating conventional dendrite puncture and prolonging life expectancy by an order of magnitude. It is found that SDF/AFZMB exhibits a long circulation of 2000 cycles with 89.0% capacity retention at 5 C with superior flexibility, demonstrating potential for application in future wearable electronics. [ABSTRACT FROM AUTHOR]

In a switchgear, an external transverse magnetic field (ETMF) is generated by the U type loop consisting of the vacuum interrupter, external busbar and conductive rod connected to the vacuum interrupter. The ETMF will make the vacuum arc deflected and strengthen the contraction of the arc. This can increase the probability of breaking failure. To weaken the adverse effect of the ETMF, the real magnetic field data of the arc area with different structure parameters when the length of conductive rod, external busbar and phase distance is changed are obtained by establishing simulation model in this paper. Taking the real magnetic field data as the boundary condition, this paper obtains the typical parameters of the vacuum arc plasma with different structure parameters by using the established three-dimensional high-current vacuum arc magnetohydrodynamics model. The simulation results show that the ETMF makes the transverse magnetic field (TMF) of the arc area asymmetric, which leads to an arc deflection. Reducing the length of the conductive rod connected to the vacuum interrupter to 50 mm can effectively improve the asymmetry of the TMF caused by the EMTF, weaken the arc deflection phenomenon, make the distribution of the plasma parameters more uniform, and increases the utilization of the anode contact surface. Moreover, it can not only reduce the heat flux density into the anode as a whole, but also reduce the heat flux density in the high heat flux density area, so as to effectively reduce the degree of anode activity and improve the negative effects caused by the anode activity. The changes of other external structural parameters have less influence on the improvement of the vacuum arc deflection phenomenon. Increasing the phase spacing to 275 mm or reducing the length of the external bus bar to 100 mm can only slightly weaken the arc deflection. [ABSTRACT FROM AUTHOR]

The efficient degradation and accurate quantification of tetracycline in environment and food samples is pivotal for ensuring public health and safety by monitoring potential contamination and maintaining regulatory standards. Hence, in this study, photocatalytic degradation of tetracycline and its electrochemical detection in environment and food samples based on dual-functional silver-doped zinc ferrite nanoparticles embedded chitosan-functionalized carbon nanofibers fabricated on a screen-printed carbon electrode (AgZFO/CHIT-CNF/SPCE) is presented. A hydrothermal method was used in the synthesis of Ag-doped ZFO, and chitosan was functionalized on the CNF surface using a swift and cost-effective chemical modification process of carboxyl groups. Various techniques, such as XRD, HRTEM, elemental mapping, EIS, XPS, FTIR, VSM, BET, UV–Vis DRS, and Raman spectroscopy were used to analyze the characteristics of the prepared nanocomposite. Cyclic voltammetry and differential pulse voltammetry were used to evaluate the surface-controlled electrocatalytic properties of AgZFO/CHIT-CNF towards tetracycline. Electrochemical tests revealed that the proposed electrode exhibited excellent sensitivity for detecting tetracycline. The fabricated electrode had a low detection limit of 1 nM and a wide linear range (0.2–53.2 μM). The sensor also demonstrated exceptional selectivity, stability, and reusability. The practical feasibility evaluated with real samples, including chicken feed, shrimp, milk, soil, and wastewater, resulted in high recovery values. [Display omitted] • Ultrasensitive detection of polyketide drug tetracycline based on AgZFO/CHIT-CNF/SPCE. • Photocatalytic degradation of tetracycline with high efficiency (95.72%) using dual-functional nanocomposite. • This is the first work that reports tetracycline detection using ZFO based nanomaterial. • A very low detection limit (1 nM) in nanomolar range was achieved for proposed sensor. • High recovery values for practical feasibility analysis in wastewater, soil, chicken feed, shrimp, and milk. [ABSTRACT FROM AUTHOR]

The efficient degradation and accurate quantification of tetracycline in environment and food samples is pivotal for ensuring public health and safety by monitoring potential contamination and maintaining regulatory standards. Hence, in this study, photocatalytic degradation of tetracycline and its electrochemical detection in environment and food samples based on dual-functional silver-doped zinc ferrite nanoparticles embedded chitosan-functionalized carbon nanofibers fabricated on a screen-printed carbon electrode (AgZFO/CHIT-CNF/SPCE) is presented. A hydrothermal method was used in the synthesis of Ag-doped ZFO, and chitosan was functionalized on the CNF surface using a swift and cost-effective chemical modification process of carboxyl groups. Various techniques, such as XRD, HRTEM, elemental mapping, EIS, XPS, FTIR, VSM, BET, UV–Vis DRS, and Raman spectroscopy were used to analyze the characteristics of the prepared nanocomposite. Cyclic voltammetry and differential pulse voltammetry were used to evaluate the surface-controlled electrocatalytic properties of AgZFO/CHIT-CNF towards tetracycline. Electrochemical tests revealed that the proposed electrode exhibited excellent sensitivity for detecting tetracycline. The fabricated electrode had a low detection limit of 1 nM and a wide linear range (0.2–53.2 μM). The sensor also demonstrated exceptional selectivity, stability, and reusability. The practical feasibility evaluated with real samples, including chicken feed, shrimp, milk, soil, and wastewater, resulted in high recovery values. [Display omitted] • Ultrasensitive detection of polyketide drug tetracycline based on AgZFO/CHIT-CNF/SPCE. • Photocatalytic degradation of tetracycline with high efficiency (95.72%) using dual-functional nanocomposite. • This is the first work that reports tetracycline detection using ZFO based nanomaterial. • A very low detection limit (1 nM) in nanomolar range was achieved for proposed sensor. • High recovery values for practical feasibility analysis in wastewater, soil, chicken feed, shrimp, and milk. [ABSTRACT FROM AUTHOR]

• Uniform Co 2 (OH) 3 Cl hollow microspheres are prepared by an one-step solvothermal route. • The Co 2 (OH) 3 Cl presents an activation-enhanced OER performance after CV cycles. • Small amounts of Fe modification further increase OER activity of Co 2 (OH) 3 Cl. • Fe doping makes the lattice Cl− etching easier and generates more surface vacancies. • Fe modification can result in the moderate surface oxygen adsorption affinity. Surface self-reconstruction by the electrochemical activation is considered as an effective strategy to increase the oxygen evolution reaction (OER) performance of transition metal compounds. Herein, uniform Co 2 (OH) 3 Cl microspheres are developed and present an activation-enhanced OER performance caused by the etching of lattice Cl− after 500 cyclic voltammetry (CV) cycles. Furthermore, the OER activity of Co 2 (OH) 3 Cl can be further enhanced after small amounts of Fe modification (Fe2+ as precursor). Fe doping into Co 2 (OH) 3 Cl lattices can make the etching of surface lattice Cl− easier and generate more surface vacancies to absorb oxygen species. Meanwhile, small amounts of Fe modification can result in a moderate surface oxygen adsorption affinity, facilitating the activation of intermediate oxygen species. Consequently, the 10% Fe-Co 2 (OH) 3 Cl exhibits a superior OER activity with a lower overpotential of 273 mV at 10 mA cm−2 (after 500 CV cycles) along with an excellent stability as compared with commercial RuO 2. [ABSTRACT FROM AUTHOR]

A novel STING agonist, CDGSF, ipsilaterally modified with phosphorothioate and fluorine, was synthesized. The phosphorothioate in CDGSF might be a site for covalent conjugation. Injection of CDGSF generated an immunogenic ("hot") tumor microenvironment to suppress melanoma, more efficiently than dithio CDG. In particular, immunization with SARS-CoV-2 spike protein using CDGSF as an adjuvant elicited an exceptionally high antibody titer and a robust T cell response, overcoming the drawbacks of aluminum hydroxide. These results highlighted the therapeutic potential of CDGSF for cancer immunotherapy and the adjuvant potential of the STING agonist in the SARS-CoV-2 vaccine for the first time. [ABSTRACT FROM AUTHOR]

Images created from measurements made by wireline microresistivity imaging tools have longitudinal gaps when the well circumference exceeds the total width of the pad-mounted electrode arrays. The gap size depends on the tool design and borehole size, and the null data in these gaps negatively affect the quantitative evaluation of reservoirs. Images with linear and texture features obtained from microresistivity image logs have distinct dual fabric features because of logging principles and various geological phenomena. Linear image features usually include phenomena such as fractures, bedding, and unconformities. Contrarily, texture-based image features usually indicate phenomena such as vugs and rock matrices. According to the characteristics of this fabric-based binary image structure and guided by the practice of geological interpretation, an adaptive inpainting method for the blank gaps in microresistivity image logs is proposed. For images with linear features, a sinusoidal tracking inpainting algorithm based on an evaluation of the validity and continuity of pixel sets is used. Contrarily, the most similar target transplantation algorithm is applied to texture-based images. The results obtained for measured electrical imaging data showed that the full borehole image obtained by the proposed method, whether it was a linear structural image reflecting fracture and bedding or texture-based image reflecting the matrix and pore of rock, had substantially good inpainting quality with enhanced visual connectivity. The proposed method was effective for inpainting electrical image logs with large gaps and high angle fractures with high heterogeneity. Moreover, ladder and block artifacts were rare, and the inpainting marks were not obvious. In addition, detailed full borehole images obtained by the proposed method will provide an essential basis for interpreting geological phenomena and reservoir parameters. [ABSTRACT FROM AUTHOR]

Cellular aging occurs as a cell loses its ability to maintain homeostasis. Aging cells eliminate damaged cellular compartments and other senescence factors via self-renewal. The mechanism that regulates cellular rejuvenation remains to be further elucidated. Using budding yeast gametogenesis as a model, we show here that the endosomal sorting complex required for transport (ESCRT) III regulates nuclear envelope organization. During gametogenesis, the nuclear pore complex (NPC) and other senescence factors are sequestered away from the prospore nuclei. We show that the LEM-domain protein Heh1 (Src1) facilitates the nuclear recruitment of ESCRT-III, which is required for meiotic NPC sequestration and nuclear envelope remodeling. Furthermore, ESCRT-III-mediated nuclear reorganization appears to be critical for gamete rejuvenation, as hindering this process curtails either directly or indirectly the replicative lifespan in gametes. Our findings demonstrate the importance of ESCRT-III in nuclear envelope remodeling and its potential role in eliminating senescence factors during gametogenesis. [ABSTRACT FROM AUTHOR]

An electrochemical immunosensor based on ferrocene (Fc)-functionalized nanocomposites was fabricated as an efficient electroactive signal probe to amplify electrochemical signals for Salmonella typhimurium detection. The electrochemical signal amplification probe was constructed by encapsulating ferrocene into S. typhimurium–specific antimicrobial peptides Magainin I (MI)-Cu3(PO4)2 organic-inorganic nanocomposites (Fc@MI) through a one-step process. Magnetic beads (MBs) coupled with antibody were used as capture ingredient for target magnetic separation, and Fc@MI nanoparticles were used as signal labels in the immunoassays. The sandwich of MBs-target-Fc@MI assay was performed using a screen-printed carbon electrode as transducer surface. The immunosensor platform presents a low limit of detection (LOD) of 3 CFU·mL−1 and a linear range from 10 to 107 CFU·mL−1, with good specificity and precision, and was successfully applied for S. typhimurium detection in milk. [ABSTRACT FROM AUTHOR]

We report first principles modeling of quantum tunneling through amorphous HfO2 dielectric layer of metal-oxide-semiconductor (MOS) nanostructures in the form of n-Si/HfO2/Al. In particular, we predict that chemically modifying the amorphous HfO2 barrier by doping N and Al atoms in the middle region—far from the two interfaces of the MOS structure—can reduce the gate-to-channel tunnel leakage by more than one order of magnitude. Several other types of modification are found to enhance tunneling or induce substantial band bending in the Si, both are not desired from leakage point of view. By analyzing transmission coefficients and projected density of states, the microscopic physics of electron traversing the tunnel barrier with or without impurity atoms in the high-κ dielectric is revealed. [ABSTRACT FROM AUTHOR]

Different from conventional method templated by metal ions, G-quadruplex assemblies could be constructed by the promotion of cationic surfactant CTAB in this work, providing a novel approach to constructing G-quadruplex structures. • G-quadruplex structures were constructed via self-assembly of a guanosine derivative. • A great many G-quadruplex systems were induced by metal ions. • However, the G-quadruplex structures here were induced by cationic surfactants. • This is a novel strategy to construct G-quadruplex. • The morphology and structure can be tuned by changing the amount of surfactant. G-quadruplex structure has raised increasing attention in supramolecular chemistry as an effective template for ordered functional materials. Thus, it is of practical significance to advance our understanding regarding G-quadruplex structures. Typically, G-quadruplex structures are formed in the presence of suitable metal ions. New methods to construct such structures need to be explored. The supramolecular assembly between CTAB and a guanosine derivative at different molar ratios was systematically studied, including assembly mechanisms, morphology, and macroscopic properties. Cationic surfactants with different alkyl chains were studied as control experiments. A novel strategy to construct G-quadruplex with the promotion of the cationic surfactant CTAB is presented in this work. The structure-property relationships of G-quadruplex gels are characterized by rheology and shrinkage ratio experiments. MacKintosh's theory was used to rationalize the relationship between gel elasticity and water content. The transition of G-quadruplex structures could be easily enabled by modulating CTAB concentration, which promotes the phase transition from gel/sol biphase to homogeneous sol phase. This work will provide a new viewpoint for the construction and modulation of G-quadruplex structures. [ABSTRACT FROM AUTHOR]

Plasmonic sensing relies on the interaction between the electromagnetic light wave and free electrons that reside at the interface of two materials, one of them being a metal. Surface plasmon resonance (SPR)‐based biosensing has distinct advantages of providing real‐time and label‐free detection technique that is capable of giving accurate and repeatable results. 2D nanomaterials (graphene and transition metal dichalcogenides [TMDCs] such as MoS2 and WS2) have recently gained high popularity in the field of biomedical sciences. Using Biacore commercial SPR machine manufactured by GE Healthcare, the efficacy of various combinations of these materials coated on the plasmonic metal gold (Au) (Au + MoS2, Au + WS2, Au + graphene, Au + graphene + MoS2, and Au + graphene + WS2) is evaluated, in enhancing the sensitivity of the biosensor as compared with the standard Kretschmann configuration (only Au). Some simulation results are also presented at incident light wavelengths of 633 and 785 nm that are based on the angular interrogation method. To conclude, it is found that the sensitivity in the increasing order is: only Au < Au + MoS2 < Au + WS2 ≈ Au + graphene < Au + graphene + MoS2 < Au + graphene + WS2. [ABSTRACT FROM AUTHOR]

The article explores the understanding the relationship between brain activity and specific mental function as important for medical diagnosis of brain symptoms, such as epilepsy. It discusses about the Magnetoencephalography, which uses an array of highsensitivity magnetometers to record magnetic field signals generated from neural currents occurring naturally in the brain, as a noninvasive method for locating the brain activities.

The hierarchical nanosheets and hollow structure provide excellent electrochemical stability along with sufficient surface area and ion transpotation channels. The hierarchical nanosheets and hollow structure has been demonstrated to be an effective way to elevate the storage abilities of MoS 2 materials for KIB, which not only provides sufficient void space to accommodate volume expansion, but also facilitates the potassium ion diffusion. Molybdenum disulfide (MoS 2) is a promising nanomaterial which has been extensively investigated in photo-/electro-catalysis, sensors, and batteries due to its excellent physical/chemical properties. In this manuscript, MoS 2 hierarchical nanotubes with hollow nanostructure are successfully synthesized via a facile hydrothermal method. SEM indicates that such MoS 2 nanotubes have perfect uniformity while TEM demonstrates the hollow structure. Specifically, the ratio of MoS 2 to the randomly produced polysulfide in the synthesized MoS 2 nanotubes is 4.29 which confirms that the synthesized MoS 2 nanotubes have quite high quality. Compared with the previous studies, our MoS 2 nanotubes show superior rate capability and cyclability (127 mAh g−1 at 200 mA g−1 after 100 cycles) in the potassium ion battery. [ABSTRACT FROM AUTHOR]

When tunnel blasting is commenced through the subway station, it will cause the vibration of the station structure. The purpose of this paper is to explore the maximum allowable vibration velocity of the normal operation of the subway during the implementation process of tunneling projects, and to ensure the normal and safe operation of the subway during the construction. An example is given regarding the down-traversing of the power tunnel to the Convention and Exhibition Center Station in the Yanta four circuit transmission line transformation project of Dalian, in which the stations are set along the track bed and bottom of the side walls of the rail line. The vibration response and corresponding main vibration frequency at each station were monitored. It was found that the response value of the vibration velocity of the track bed was distributed 0.5 to 2.0 cm/s; the average response value of the vibration velocity on one side wall for the previous construction on the rail line is 0.3 cm/s, and the distribution range of the main vibration frequency is 50 to 140 Hz; the response of the vibration velocity on the other side wall for the subsequent construction on the rail line is large with a mean value of 0.6 cm/s, and the distribution range of the main vibration frequency is 40 to 180 Hz. Based on these research results and the relevant specifications, the authors state that the monitoring work on the normal operation of the subway should be based on the monitoring work of the track bed and should allow the maximum vibration velocity of the particles to be 1.1 cm/s and 0.8 cm/s, and the corresponding main vibration frequency ranges of 70 to 100 Hz and 35 to 60 Hz, respectively. The present paper’s research results are of use as guidance for further studies and they put forth the maximum allowable particle velocity of subway operation during tunnel blasting construction of a down-traversing subway station. [ABSTRACT FROM AUTHOR]

Although a massive research has been devoted on the exploration of noble metal–based nanozyme, less progress has been made in the investigation of palladium (Pd) nanozyme and the interaction between ions and Pd nanozyme. In this study, a new type of Pd nanozyme was prepared by a facile one-pot approach by using carboxylated chitosan as the stabilizer. Owing to the synergistic effect of carboxylated chitosan stabilized Pd nanoparticles (CC-PdNPs) can effectively catalyze the H2O2-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine sulfate (TMB) accompanied by a blue color change (oxidized TMB), indicating the peroxidase-like activity of CC-PdNPs. Furthermore, the Michaelis-Menten constants and catalytic stability of CC-PdNPs render them suitable for environmental analysis and bio-detection. Here, we found that while introducing the iodine ions (I−) into the reaction medium, the peroxidase-like activity of CC-PdNPs has been rapidly and effectively inhibited through the formation of Pd-I bond; thus, the active sites of PdNPs can be blocked by I−. Based on this specific inhibition by I−, a facile colorimetric assay has been performed for the detection of I− with an extremely low limit of detection (0.19 nM). Furthermore, the practicality of the proposed sensor also has been demonstrated in tap water, and the satisfactory recoveries were obtained. Our study not only demonstrated a novel Pd–based nanozyme but also provided guidance for I− sensing for environmental analysis, food inspection, and bio-detection. [ABSTRACT FROM AUTHOR]

The AAA + ATPase R2TP complex facilitates assembly of a number of ribonucleoprotein particles (RNPs). Although the architecture of R2TP is known, its molecular basis for acting upon multiple RNPs remains unknown. In yeast, the core subunit of the box C/D small nucleolar RNPs, Nop58p, is the target for R2TP function. In the recently observed U3 box C/D snoRNP as part of the 90 S small subunit processome, the unfolded regions of Nop58p are observed to form extensive interactions, suggesting a possible role of R2TP in stabilizing the unfolded region of Nop58p prior to its assembly. Here, we analyze the interaction between R2TP and a Maltose Binding Protein (MBP)-fused Nop58p by biophysical and yeast genetics methods. We present evidence that R2TP interacts largely with the unfolded termini of Nop58p. Our results suggest a general mechanism for R2TP to impart specificity by recognizing unfolded regions in its clients. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Preparation of MC using loofah as raw material. • The MC exhibits excellent physical and chemical properties. • The SnS 2 /MC photocatalyst exhibits excellent photocatalytic activity. Abstract In this study, a novel nanocomposite, carbon/SnS 2 with 3D hierarchical macroporous (MCS), was successfully prepared for rapid photocatalytic treatment of hexavalent chromium (Cr(VI)). The 3D macroporous carbon (MC) can be obtained through a simple carbonization process of loofah. Since the MCS has a large specific surface area, it can provide numerous photocatalytic active sites and has excellent adsorption properties for the Cr(VI). In addition, the excellent electrical conductivity and unique hierarchical nanoarchitecture of macroporous biomass carbon could rapidly absorb the Cr(VI) from wastewater and provide electron transport tunnel for rapid charge separation/transport to suppress hole electron recombination. It is confirmed that such three dimensional photocatalytic material can quickly purify Cr(VI)-containing wastewater under mild visible light irradiation, with a efficiency of 63.2% Cr(VI) reduction within 120 mins. Besides the high visible light-driven photocatalytic activity, MCS also exhibits excellent cycling stability. In addition, the SEM images of MCS before and after photocatalytic removal of Cr(VI) indicate that the morphology of composite was perfectly maintained and no peeling-off of SnS 2 was observed. More importantly, this study demonstrated that MCS can be used for practical applications due to its stability and economic availability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Prepared a biodegradable elastomer for electrospinning using modified PPC Polyols. • AMMT-3 has superior performance compared to current commercial products. • AMMT-3 is biodegradable and no adverse reactions when applied to the skin surface. • The research demonstrated the feasibility of industrial production of AMMT-3. The widespread use of medical tapes in healthcare settings poses challenges related to cross-contamination, incidents resulting from improper usage, and environmental pollution caused by the accumulation and disposal of medical waste. Consequently, there is an urgent need to develop a antibacterial and biodegradable medical tape. Herein, an antibacterial and biodegradable medical tape has been demonstrated to address these problems. The novel approach involves the synthesis of a series of high molecular weight polypropylene carbonate (PPC) elastomers combined with antibacterial agents like benzalkonium bromide to enhance bacterial growth resistance and prevent cross-contamination. The integration of the electrospinning technique enables the production of micro-nano fiber membranes with excellent breathability and moisture permeability. The newly developed antibacterial micro-nano medical tape (AMMT) demonstrates superior breathability (43.07 mm·s−1, 1.2 times to similar commercial products from 3 M), moisture permeability (6,589.40 g·m−2·d−1), and skin-friendliness. Furthermore, the outstanding antibacterial performance of this tape, with a 100% antibacterial rate, combined with its biodegradability, positions it as a highly promising material for applications in medical dressings and tissue engineering. [ABSTRACT FROM AUTHOR]

The nanostructures based on polymers have attracted much research interest because of their rich morphologies, unique properties and potential applications in various fields. In particular, helical nanostructures have been research hotspots in recent years. In this work, composite non-helical and helical nanowire arrays of atactic poly(2-vinylpyridine) (P2VP), and block copolymers polystyrene- block -poly(2-vinylpyridine) (PS- b -P2VP) were fabricated successfully with inorganic species such as HAuCl 4 through a liquid/liquid interfacial adsorption and self-assembly approach without addition of any chiral inducers. The formation process of the helical nanowires of P2VP includes the following steps, i.e. adsorption of the polymer molecules and HAuCl 4 at the interface, the following protonation of pyridine groups, straightening of the P2VP chains by mutual repulsion between the protonated pyridine groups, aggregation of the P2VP chains due to the hydrophobic interactions between the backbones, and ordered organization of the pyridine groups through π-π interactions. The helical nanowires of PS- b -P2VP are worm-like micelles with a PS core and a P2VP shell, which are formed through the self-assembly of the block copolymer molecules with HAuCl 4 within the interfacial phase with the help of hydrophobic interaction between the PS blocks and orderly stacking of the P2VP blocks. The different formation mechanisms reflected the effects of molecular structure on the self-assembly of polymers. In addition, the formed nanowires further self-organize into ordered arrays due to the increasing interfacial pressure during the generation of the nanowires. The results of this study expand the scope of research on polymer self-assembly and the application of liquid/liquid interfacial self-assembly techniques to acquire highly ordered supramolecular nanostructures. [Display omitted] • PS and PS-b-P2VP self-assembled into helical nanowires with chloroauric acid. • The nanowires formed in the liquid/liquid interfacial phase. • These nanowires further organized into parallel arrays. • The PS nanowires result from chain straightening, aggregation and ordered packing. • The PS-b-P2VP nanowires are actually worm-like micelles. [ABSTRACT FROM AUTHOR]

Using ab initio methods, we have calculated the characteristic inverse length scale for spin polarized tunneling in Langmuir-Blodgett (LB) films contacted by Fe electrodes. As a function of energy, the scale is found to vary significantly around its mean value, and the variation is much more drastic in parallel configuration than that of anti-parallel configuration. This unusual behavior can be understood. from the point of view of interface resonance, which shows very sharp features in the k-space resolved transmission probability. [ABSTRACT FROM AUTHOR]

Ellipsoidal and spherical superstructures, network structure and hierarchical structure of noble metal spherical or rod-like nanoparticles were fabricated through a liquid/liquid interface mass transfer-assisted self-assembly process in aqueous solutions. • A general approach has been developed to fabricate superstructures of nanoparticles. • A liquid/liquid interface mass transfer process was used to introduce amines into hydrosols. • The fatty amines combined with colloidal particles and organized into superstructures. • Ellipsoidal and spherical superlattices of spherical nanoparticles were obtained. • Network and hierarchical structures of nanospheres and nanorods were obtained. Organized assemblies of noble metal nanoparticles (NPs) exhibit unique optical, electronic and catalytic properties and potential applications in various areas. Many kinds of methods have been developed to fabricate such functional systems. In this work, we report a facile and novel method to fabricate the organized aggregates of Au and Ag NPs. Their freshly prepared hydrosols were used as upper phase, and the DMF/chloroform solutions of different fatty amines were used as bottom phases to form a planar liquid/liquid interface. The mass transfer across the interface occurred immediately, where the DMF droplets containing fatty amines entered into the hydrosols, leading to the formation of organized aggregates of NPs through a self-assembly process of amine molecules. It was found that several kinds of assemblies were generated, including ellipsoidal and spherical superstructures of spherical NPs, networks of spherical NPs and nanorods, and hierarchical structure of nanorods. In addition, networks composed of Au NPs/Ag skeleton satellite-core type nanorods were further constructed, which exhibited good catalytic performance and SERS property. [ABSTRACT FROM AUTHOR]

Amphiphilic block copolymers can self-assemble into various aggregates in which functional inorganic nanoparticles and organic chromophores can be incorporated. A variety of fabrication methods have been developed. In this work, the liquid/liquid interface mass transfer-assisted self-assembly method was extended to fabricate composite organized structure of polystyrene-b-polyacrylic acid (PS-b-PAA) with small organic molecules, such as diamines, dopamine and dyes. It was found that long uniform nanowires, hollow spheres and foams were generated when using these organic molecules under different conditions, which correspond to worm-like micelles, vesicles and aggregates of microcapsules, respectively. The length of the nanowires reaches to several tens of micrometers. The influence of the molecular structure of the organic molecules, especially the diamines was investigated and discussed, and the formation mechanism of these aggregates was analyzed. This method may be developed to a facile and useful approach to fabricate functional composite structure of block copolymers and small molecules. [ABSTRACT FROM AUTHOR]

We propose a gate-controllable spin-battery for spin current. The spin battery consists of a lateral double quantum dot under a uniform magnetic field. A finite dc spin current is driven out of the device by controlling a set of gate voltages. Spin current can also be delivered in the absence of charge current. The proposed device should be realizable using present technology at low temperature. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Exploitation of earth-abundant, cost-effective and high-efficient bifunctional electrocatalysts for overall water spitting in basic media is highly desirable, yet it remains a big challenge. Here, NiFe Layered-double-hydroxide nanosheet-anchored CoSe nanotubes (composed of plicated nanosheets) supported on Ni foam are prepared through our developed hydrothermal-selenization-hydrothermal method. Benefiting from the unique nanoarchitecture, optimized adsorption/desorption of oxygenated species at the interface (owing to the re-delocalization of electron spin status via π-donation), the bifunctional hybrid catalysts exhibit low overpotentials of 201 and 98 mV at 10 mA cm−2 for oxygen evolution reaction and hydrogen evolution reaction in 1 M KOH aqueous solution, respectively. Particularly, the full-cell only requires 1.53 V to drive a current density of 10 mA cm−2 when choosing the hybrid catalysts serving as both anode and cathode, being superior than that of the state-of-the-art commercial noble-metal based cells for overall water splitting. This work presents a general strategy to boost the oxygen evolution reaction and hydrogen evolution reaction kinetics of selenides, which is also expected to extend to other noble-metal-free catalysts. Image 1 • A three-step strategy was developed for synthesis of CoSe@NiFe-LDH electrocatalyst. • Re-localization of electron spin status was occurred at the interface. • The constructed full-cell requires 1.53 V to drive a current density of 10 mA cm−2. • CoSe@NiFe-LDH electrocatalysts exhibit both splendid OER and HER activities. [ABSTRACT FROM AUTHOR]

PS-b-PAA/copper composite two-dimensional nanoflowers with highly heterogeneous catalytic activity and good stability was fabricated at the liquid/liquid interface. To design and prepare heterogeneous catalysts with both high catalytic activity and good stability is still a challenge. Herein, we fabricated a composite Cu/PS-b-PAA film consisting of unique nanoflowers for the heterogeneous catalytic reactions such as hydrogenation of nitroarenes in aqueous solutions at the planar liquid/liquid interface through the interfacial adsorption and self-assembly process. The nanoflowers are comprised of nanoplates with a thickness of about 10 nm. The nanoplates have layered structure composed of an inner layer of hydrophobic PS and two surface layers of hydrophilic PAA where the copper species are dispersed. The composite film exhibited high catalytic activity for the reduction of p -nitroaniline (p -NA) in aqueous solutions and the rate constant reached to 396.45 s−1 g−1. Inaddition, the composite film also showed good stability and high recyclability without any changes in the rate constant and conversion efficiency in 15 successive cycles. These should be attributed to the special structure of the composite nanoflowers. We developed an excellent heterogeneous catalyst system possessed of both high activity and good stability through delicate design and fabrication. [ABSTRACT FROM AUTHOR]

The nucleus is enclosed by the inner nuclear membrane (INM) and the outer nuclear membrane (ONM). While the ONM is continuous with the endoplasmic reticulum (ER), the INM is independent and separates the nucleoplasm from the ER lumen. Turnover of ER proteins has been well characterized by the ER-associated protein degradation (ERAD) pathway, but very little is known about turnover of resident INM proteins. Here we show that the anaphase-promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase, regulates the degradation of Mps3, a conserved integral protein of the INM. Turnover of Mps3 requires the ubiquitin-conjugating enzyme Ubc7, but was independent of the known ERAD ubiquitin ligases Doa10 and Hrd1 as well as the recently discovered Asi1-Asi3 complex. Using a genetic approach, we have found that Cdh1, a coactivator of APC/C, modulates Mps3 stability. APC/C controls Mps3 degradation through Mps3's N terminus, which resides in the nucleoplasm and possesses two putative APC/C-dependent destruction motifs. Accumulation of Mps3 at the INM impairs nuclear morphological changes and cell division. Our findings therefore reveal an unexpected mechanism of APC/C-mediated protein degradation at the INM that coordinates nuclear morphogenesis and cell cycle progression. [ABSTRACT FROM AUTHOR]

The autotoxicity of root exudates and the change of rhizosphere soil microbes are two important factors that affect the quality and yield of Lanzhou lily (Lilium davidii var. unicolor). Phthalic acid (PA) is a major autotoxin of the root exudates in Lanzhou lily. In this study, we treated plants with different concentrations of PA from the Lanzhou lily root exudates and then analyzed the effects of autotoxins on fresh weight, shoot height, root length, and Oxygen Radical Absorbance Capacity in root. The diversity of soil fungi in Lanzhou lily soil was analyzed using MiSeq. The results showed that PA induced oxidative stress and oxidative damage of Lanzhou lily roots, improved the level of the membrane lipid peroxidation, reduced the content of antioxidant defense enzyme activity and the nonenzymatic antioxidant, and eventually inhibited the growth of the Lanzhou lily. We found that continuous cropping of Lanzhou lily resulted in an increase in fungal pathogens, such as Fusarium oxysporum in the soil, and reduced the size of plant-beneficial bacteria populations. The results in this study indicate that continuous cropping would damage the regular growth of Lanzhou lily. [ABSTRACT FROM AUTHOR]