2,230 research outputs found

    Magnetic Resonance imaging (MRI) in detection of _Bifidobacterium longum_ and _Clostridium novyi-NT_ labeled with superparamagnetic iron oxide (SPIO) nanoparticle

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    *Purpose:* To investigate the MR imaging of _Bifidobacterium longum_ and _Clostridium novyi-NT_ labeling with superparamagnetic iron oxide (SPIO) nanoparticles.

*Materials and methods:* Tubes containing _B. longum_-SPIO, Free-SPIO, _B. longum_ and PYG Medium were incubated under anaerobic condition in _in vitro_ experiment. Transmission electron microscope and Prussian blue staining were used to demonstrate intra-bacteria nanoparticles. R~2~^*^ mapping and R~2~ mapping were reconstructed after MR scanning. _B. longum_-SPIO and _C. novyi_-NT-SPIO were injected respectively _in vivo_ to show whether it might be traced by MR imaging.

*Results:* Magnetosomes in bacteria were observed by electron microscopic and stained by Prussian blue staining. At the same concentration of SPIOs, the R~2~^*^ value of _B. longum_-SPIO was significantly higher than that of Free-SPIO (P<0.001), however, the R~2~ value was lower comparing with Free-SPIO (P<0.001). After injection with _B. longum_-SPIO, they could present in tumor and shorten T~2~^*^.

*Conclusion:* _B. longum_ and _C. novyi_-NT could be labeled by SPIO and then traced by MRI

    Composite Cyclotomic Fourier Transforms with Reduced Complexities

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    Discrete Fourier transforms~(DFTs) over finite fields have widespread applications in digital communication and storage systems. Hence, reducing the computational complexities of DFTs is of great significance. Recently proposed cyclotomic fast Fourier transforms (CFFTs) are promising due to their low multiplicative complexities. Unfortunately, there are two issues with CFFTs: (1) they rely on efficient short cyclic convolution algorithms, which has not been investigated thoroughly yet, and (2) they have very high additive complexities when directly implemented. In this paper, we address both issues. One of the main contributions of this paper is efficient bilinear 11-point cyclic convolution algorithms, which allow us to construct CFFTs over GF(211)(2^{11}). The other main contribution of this paper is that we propose composite cyclotomic Fourier transforms (CCFTs). In comparison to previously proposed fast Fourier transforms, our CCFTs achieve lower overall complexities for moderate to long lengths, and the improvement significantly increases as the length grows. Our 2047-point and 4095-point CCFTs are also first efficient DFTs of such lengths to the best of our knowledge. Finally, our CCFTs are also advantageous for hardware implementations due to their regular and modular structure.Comment: submitted to IEEE trans on Signal Processin

    Continuous fabrication of calcium sulfate whiskers with adjustable aspect ratio in microdroplets

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    Hemi-hydrate and anhydrous CaSO₄ whiskers with adjustable aspect ratio were continuously synthesized by the reactive crystallization of CaCl₂ to K₂ S₂ O₈ in microdroplets. The effects of solvent and reactive temperature were examined, with SEM and XRD characterizations. Hemi-hydrate and anhydrous CaSO₄ whiskers can be, respectively, obtained in aqueous and N,N-dimethylformamide solutions at 90 °C in 180 s. The addition of ethylene glycol or glycerol as well as increasing temperature could lead to the increase in length and aspect ratio of the whiskers. Thus this preparation technique provides a simple continuous route to synthesize CaSO₄ whiskers with two kinds of crystal structures in a short time, and adjustable lengths and aspect ratios

    Elaboration and characterization of nanoplate structured alpha-Fe2O3 films by Ag3PO4

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    A new strategy for surface treatment of hematite nanoplates for efficient photoelectrochemical (PEC) performances is proposed. Silver orthophosphate (Ag₃PO₄) has been adopted to mediate the formation of α-Fe₂O₃ films. Phosphate ions in Ag₃PO₄ is found to cause a significant morphology change during annealing process, from β-FeOOH nanorod arrays to hematite nanoplates. Meanwhile, Ag ions is doped into α-Fe₂O₃ film. The obtained nanoplate structured Fe₂O₃ –Ag–P films demonstrate much higher photoelectrochemical performance as photoanodes than the bare Fe₂O₃ nanorod thin films. The effects of phosphate and silver ions on the morphology, surface characteristics and the PEC properties of the photoanodes are investigated

    Dual mTOR/PI3K inhibition limits PI3K-dependent pathways activated upon mTOR inhibition in autosomal dominant polycystic kidney disease

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    Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the development of kidney cysts leading to kidney failure in adulthood. Inhibition of mammalian target of rapamycin (mTOR) slows polycystic kidney disease (PKD) progression in animal models, but randomized controlled trials failed to prove efficacy of mTOR inhibitor treatment. Here, we demonstrate that treatment with mTOR inhibitors result in the removal of negative feedback loops and up-regulates pro-proliferative phosphatidylinositol 3-kinase (PI3K)-Akt and PI3K-extracellular signal-regulated kinase (ERK) signaling in rat and mouse PKD models. Dual mTOR/PI3K inhibition with NVP-BEZ235 abrogated these pro-proliferative signals and normalized kidney morphology and function by blocking proliferation and fibrosis. Our findings suggest that multi-target PI3K/mTOR inhibition may represent a potential treatment for ADPKD

    Large-surface-area BN nanosheets and their utilization in polymeric composites with improved thermal and dielectric properties

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    High-throughput few-layered BN nanosheets have been synthesized through a facile chemical blowing route. They possess large lateral dimensions and high surface area, which are beneficial to fabricate effectively reinforced polymeric composites. The demonstrated composites made of polymethyl methacrylate and BN nanosheets revealed excellent thermal stability, 2.5-fold improved dielectric constant, and 17-fold enhanced thermal conductivity. The results indicate multifunctional practical applications of such polymeric composites in many specific fields, such as thermoconductive insulating long-lifetime packaging for electrical circuits

    DNA Checkpoint and Repair Factors Are Nuclear Sensors for Intracellular Organelle Stresses-Inflammations and Cancers Can Have High Genomic Risks.

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    Under inflammatory conditions, inflammatory cells release reactive oxygen species (ROS) and reactive nitrogen species (RNS) which cause DNA damage. If not appropriately repaired, DNA damage leads to gene mutations and genomic instability. DNA damage checkpoint factors (DDCF) and DNA damage repair factors (DDRF) play a vital role in maintaining genomic integrity. However, how DDCFs and DDRFs are modulated under physiological and pathological conditions are not fully known. We took an experimental database analysis to determine the expression of 26 DNA D
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