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In this study, we investigate the spin Hall effect in heterostructures of Bi0.85Sb0.15 (10 nm) topological insulator/Ru(Ti)/Ta/Co20Fe60B20/MgO with perpendicular magnetic anisotropy. By optimizing the Ru (Ti) interfacial layer thickness as well as deposition condition of BiSb, we achieve a large effective spin Hall angle of 6.0 ± 0.1 and relatively high electrical conductivity of 1.5 × 105 Ω−1 m−1 at room temperature. We, then, demonstrate spin–orbit torque-induced magnetization switching driven by a small threshold current density of 1 × 106 Acm−2. Benchmarking shows that the writing power consumption of our stack is 2–3 orders smaller than that of heavy metals. [ABSTRACT FROM AUTHOR]

Nanofibre-based optical cavities are particularly useful for quantum optics applications, such as the development of integrated single-photon sources, and for studying fundamental light–matter interactions in cavity quantum electrodynamics (cQED). Although several techniques have been used to produce such cavities, focussed ion beam (FIB) milling is becoming popular; it can be used for the fabrication of complex structures directly in the nanofibre. However, it is challenging to mill insulating materials with highly curved geometries and large aspect ratios, such as silica nanofibres, due to charge accumulation in the material. In this article, we highlight the main features of nanofibres and briefly review cQED with nanofibre-based optical cavities. An overview of the milling process is given with a summary of different FIB milled devices and their applications. Finally, we present our technique to produce nanofibre cavities by FIB milling. To overcome the aforementioned challenges, we present a specially designed base plate with an indium tin oxide (ITO)-coated Si substrate and outline our procedure, which improves stability during milling and increases repeatability. [ABSTRACT FROM AUTHOR]

We used a micromagnetic model to study the head remanence of a perpendicular tapered main pole head. To reduce the head pole tip remanence, a single magnetic domain structure forming a vortex state from the pole tip to the tapered region is preferred. A tapered main pole structure with a trailing gap depth less than about 30 nm and a tapered angle (TGθ) equal to about 30° improved the writing efficiency. This was achieved with a head field value more than 1.3 times higher and with a head field gradient about 1.15 times higher than that of the conventional structure. Moreover, the pole tip remanence was reduced to a value closer to that of the conventional structure. The reduction in the throat height had less effect on the reduction in the head remanence in the tapered head than in the conventional head. We also discuss both single pole heads and shielded heads. [ABSTRACT FROM AUTHOR]

Hybrid lead halide perovskites have emerged as promising active materials for photovoltaic cells. Although superb efficiencies have been achieved, it is widely recognized that long-term stability is a key challenge intimately determining the future development of perovskite-based photovoltaic technology. Herein, we present reversible and irreversible photodecomposition reactions of methylammonium lead iodide (MAPbI3). Simulated sunlight irradiation and temperature (40–80 °C) corresponding to solar cell working conditions lead to three degradation pathways: (1) CH3NH2 + HI (identified as the reversible path), (2) NH3 + CH3I (the irreversible or detrimental path), and (3) a reversible Pb(0) + I2(g) photodecomposition reaction. If only the reversible reactions EQNREF(1)/EQNREF and EQNREF(3)/EQNREF take place and reaction EQNREF(2)/EQNREF can be avoided, encapsulated MAPbI3 can be regenerated during the off-illumination timeframe. Therefore, to further improve operational stability in hybrid perovskite solar cells, detailed understanding of how to mitigate photodegradation and thermal degradation processes is necessary. First, encapsulation of the device is necessary not only to avoid contact of the perovskite with ambient air, but also to prevent leakage of volatile products released from the perovskite. Second, careful selection of the organic cations in the compositional formula of the perovskite is necessary to avoid irreversible reactions. Third, selective contacts must be as chemically inert as possible toward the volatile released products. Finally, hybrid halide perovskite materials are speculated to undergo a dynamic formation and decomposition process; this can gradually decrease the crystalline grain size of the perovskite with time; therefore, efforts to deposit highly crystalline perovskites with large crystal sizes may fail to increase the long-term stability of photovoltaic devices. [ABSTRACT FROM AUTHOR]

Ribosomes routinely prepared from Escherichia coli strain K12 contain intact (70 amino acids) and short (62 amino acids) forms of ribosomal protein L31. By contrast, ribosomes prepared from ompT mutant cells, which lack protease 7, contain only intact L31, suggesting that L31 is cleaved by protease 7 during ribosome preparation. We compared ribosomal subunit association in wild-type and ompT − strains. In sucrose density gradient centrifugation under low Mg2+, 70S content was very high in ompT − ribosomes, but decreased in the wild-type ribosomes containing short L31. In addition, ribosomes lacking L31 failed to associate ribosomal subunits in low Mg2+. Therefore, intact L31 is required for subunit association, and the eight C-terminal amino acids contribute to the association function. In vitro translation was assayed using three different systems. Translational activities of ribosomes lacking L31 were 40% lower than those of ompT − ribosomes with one copy of intact L31, indicating that L31 is involved in translation. Moreover, in the stationary phase, L31 was necessary for 100S formation. The strain lacking L31 grew very slowly. A structural analysis predicted that the L31 protein spans the 30S and 50S subunits, consistent with the functions of L31 in 70S association, 100S formation, and translation. [ABSTRACT FROM AUTHOR]

Mitochondrial morphology is dynamically regulated by fusion and fission. Several GTPase proteins control fusion and fission, and posttranslational modifications of these proteins are important for the regulation. However, it has not been clarified how the fusion and fission is balanced. Here, we report the molecular mechanism to regulate mitochondrial morphology in mammalian cells. Ablation of the mitochondrial fission, by repression of Drp1 or Mff, or by over-expression of MiD49 or MiD51, results in a reduction in the fusion GTPase mitofusins (Mfn1 and Mfn2) in outer membrane and long form of OPA1 (L- OPA1) in inner membrane. RNAi- or CRISPR-induced ablation of Drp1 in HeLa cells enhanced the degradation of Mfns via the ubiquitin-proteasome system ( UPS). We further found that UPS-related protein BAT3/ BAG6, here we identified as Mfn2-interacting protein, was implicated in the turnover of Mfns in the absence of mitochondrial fission. Ablation of the mitochondrial fission also enhanced the proteolytic cleavage of L- OPA1 to soluble S- OPA1, and the OPA1 processing was reversed by inhibition of the inner membrane protease OMA1 independent on the mitochondrial membrane potential. Our findings showed that the distinct degradation systems of the mitochondrial fusion proteins in different locations are enhanced in response to the mitochondrial morphology. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC), the fifth most common cancer type and the third highest cause of cancer death worldwide, develops in different types of liver injuries, and is mostly associated with cirrhosis. However, non-alcoholic fatty liver disease often causes HCC with less fibrosis, and the number of patients with this disease is rapidly increasing. The high mortality rate and the pathological complexity of liver diseases and HCC require blood biomarkers that accurately reflect the state of liver damage and presence of HCC. Methods and Findings: Here we demonstrate that a circulating protein, apoptosis inhibitor of macrophage (AIM) may meet this requirement. A large-scale analysis of healthy individuals across a wide age range revealed a mean blood AIM of 4.99±1.8 µg/ml in men and 6.06±2.1 µg/ml in women. AIM levels were significantly augmented in the younger generation (20s–40s), particularly in women. Interestingly, AIM levels were markedly higher in patients with advanced liver damage, regardless of disease type, and correlated significantly with multiple parameters representing liver function. In mice, AIM levels increased in response to carbon tetrachloride, confirming that the high AIM observed in humans is the result of liver damage. In addition, carbon tetrachloride caused comparable states of liver damage in AIM-deficient and wild-type mice, indicating no influence of AIM levels on liver injury progression. Intriguingly, certain combinations of AIM indexes normalized to liver marker score significantly distinguished HCC patients from non-HCC patients and thus could be applicable for HCC diagnosis. Conclusion: AIM potently reveals both liver damage and HCC. Thus, our results may provide the basis for novel diagnostic strategies for this widespread and fatal disease. [ABSTRACT FROM AUTHOR]

In yeast, C-tail-anchored mitochondrial outer membrane protein Fis1 recruits the mitochondrial-fission-regulating GTPase Dnm1 to mitochondrial fission sites. However, the function of its mammalian homologue remains enigmatic because it has been reported to be dispensable for the mitochondrial recruitment of Drp1, a mammalian homologue of Dnm1. We identified TBC1D15 as a Fis1-binding protein in HeLa cell extracts. Immunoprecipitation revealed that Fis1 efficiently interacts with TBC1D15 but not with Drp1. Bacterially expressed Fis1 and TBC1D15 formed a direct and stable complex. Exogenously expressed TBC1D15 localized mainly in cytoplasm in HeLa cells, but when coexpressed with Fis1 it localized to mitochondria. Knockdown of TBC1D15 induced highly developed mitochondrial network structures similar to the effect of Fis1 knockdown, suggesting that the TBC1D15 and Fis1 are associated with the regulation of mitochondrial morphology independently of Drp1. These data suggest that Fis1 acts as a mitochondrial receptor in the recruitment of mitochondrial morphology protein in mammalian cells. [ABSTRACT FROM AUTHOR]

ABSTRACT Historical control data on rabbit prenatal developmental toxicity studies, performed between 1994-2010, were obtained from 20 laboratories, including 11 pharmaceutical and chemical companies and nine contract laboratories, in Japan. In this paper, data were incorporated from a laboratory if the information was based on 10 studies or more. Japanese White rabbits and New Zealand White rabbits were used for prenatal developmental toxicity studies. The data included maternal reproductive findings at terminal cesarean sections and fetal findings including spontaneous incidences of morphological alterations. No noticeable differences between strains or laboratories were observed in the maternal reproductive and fetal developmental data. The inter-laboratory variations in the incidences of fetal external, visceral, and skeletal alterations seem to be due to differences in the selection of observation parameters, observation criteria, and classification of the findings, and terminology of fetal alterations. [ABSTRACT FROM AUTHOR]

Mitochondrial morphology is dynamically controlled by a balance between fusion and fission. The physiological importance of mitochondrial fission in vertebrates is less clearly defined than that of mitochondrial fusion. Here we show that mice lacking the mitochondrial fission GTPase Drp1 have developmental abnormalities, particularly in the forebrain, and die after embryonic day 12.5. Neural cell-specific (NS) Drp1−/− mice die shortly after birth as a result of brain hypoplasia with apoptosis. Primary culture of NS-Drp1−/− mouse forebrain showed a decreased number of neurites and defective synapse formation, thought to be due to aggregated mitochondria that failed to distribute properly within the cell processes. These defects were reflected by abnormal forebrain development and highlight the importance of Drp1-dependent mitochondrial fission within highly polarized cells such as neurons. Moreover, Drp1−/− murine embryonic fibroblasts and embryonic stem cells revealed that Drp1 is required for a normal rate of cytochrome c release and caspase activation during apoptosis, although mitochondrial outer membrane permeabilization, as examined by the release of Smac/Diablo and Tim8a, may occur independently of Drp1 activity. [ABSTRACT FROM AUTHOR]

In order to find molecules affected by administration of an antipsychotic drug with an antimuscarinic drug, which is a common prescription used to prevent extrapyramidal adverse effects caused by the antipsychotic drugs, gene expression profiling in the frontal cortex was studied in mice. After 14 days of administration with 2 mg/kg haloperidol, a typical antipsychotic drug, and 2 mg/kg biperiden, a high-affinity antagonist for muscarinic receptors in the brain, ∼500 mRNAs related to synaptic function were investigated. The levels of the mRNAs related to the ubiquitin-related systems were significantly reduced after the combined administration. However, the separate administration of either haloperidol or biperiden had little effect on the levels of the mRNAs. This result suggests that coadministration of haloperidol and biperiden specifically affects the ubiquitin-related system. Synapse 56:175-184, 2005. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Obg proteins belong to a subfamily of GTP binding proteins, which are highly conserved from bacteria to human. Mutations of obgE genes cause pleiotropic defects in various species but the function remained unclear. Here we examine the function of ObgE, the Obg homolog inEscherichia coli. The growth rate correlates with the amount of ObgE in cells. Co-fractionation experiments further suggest that ObgE binds to 30S and 50S ribosomal subunits, but not to 70S ribosome. Pull-down assays suggest that ObgE associates with several specific ribosomal proteins of 30S and 50S subunits, as well as RNA helicase CsdA. Purified ObgE cosediments with 16S and 23S ribosomal RNAsin vitroin the presence of GTP. Finally, mutation of ObgE affects pre-16Sr-RNA processing, ribosomal protein levels, and ribosomal protein modification, thereby significantly reducing 70S ribosome levels. This evidence implicates that ObgE functions in ribosomal biogenesis, presumably through the binding to rRNAs and/or rRNA-ribosomal protein complexes, perhaps as an rRNA/ribosomal protein folding chaperone or scaffold protein. [ABSTRACT FROM AUTHOR]

Summary Deoxyadenosine methyltransferase (Dam) methylates the deoxyadenine residues in 5′ -GATC-3 ′ sequences and is important in many cellular processes in Escherichia coli . We performed a computational analysis of the entire E. coli genome and confirmed that GATC sequences are distributed unevenly in regulatory regions, which suggests that Dam might regulate gene transcription. To test this, a high-density DNA microarray of 4097 E. coli genes was constructed and used to assess the gene expression profiles of the wild type and the dam -16:: kam mutant strain grown under four different conditions. We also used two-dimensional electrophoretic analysis of the proteome to assess the protein profiles. The expression of a large number of genes was affected by the dam deficiency. Genes involved in aerobic respiration, stress and SOS responses, amino acid meta-bolism and nucleotide metabolism were expressed at higher levels in the mutant cells, especially in aerobic conditions. In contrast, transcription of genes partici-pating in anaerobic respiration, flagella biosynthesis, chemotaxis and motility was decreased in the dam mutant strain under both aerobic and low aerobic conditions. Thus, Dam-controlled genes are involved in adjusting the metabolic and respiratory pathways and bacterial motility to suit particular environmental conditions. The promoters of most of these Dam-controlled genes were also found to contain GATC sequences that overlap with recognition sites for two global regulators, fumarate nitrate reduction (Fnr) and catabolite activator protein (CRP). We propose that Dam-mediated methylation plays an important role in the global regulation of genes, particularly those with Fnr and CRP binding sites. [ABSTRACT FROM AUTHOR]

Focuses on HemK, a class of protein methyl transferase with similarity to DNA methyl transferases. Characterization of HemK knockout strains; Ability to induce translational termination; Involvement in the methylation of polypeptide chain release factors.