Monitoring of lipase-catalyzed transesterification between eicosapentaenoic acid ethyl ester and tricaprylin by silver ion high-performance liquid chromatography and high-temperature gas chromatography

A high-resolution method based on silver ion high-performance liquid chromatography (HPLC) and high-temperature gas chromatography (HTGC) with on-column injection was established for the separation of triacylglycerols (TAG) which contained eicosapentaenoic acid (EPA). A solvent system based on n-hexane, 2-propanol, and acetonitrile in HPLC for the separation of EPA-containing TAG was developed. It was dependent upon the number of EPA molecules and their isomeric distribution on the glycerol backbone. This technique was used to monitor the incorporation of EPA onto specific positions on the glycerol backbone. For quantitative monitoring of the synthesis reaction of the TAG containing EPA, an HTGC analysis was developed. For monitoring of the synthesis of structured TAG containing EPA, transesterification of tricaprylin with EPA ethyl ester in a solvent-free system was performed. The transesterification reaction using various lipases was studied at a different molar ratios of substrates, several initial water activities (a _w ), and various reaction temperatures.     

PIXE spectrum analysis taking into account bremsstrahlung spectra

Continuous background appearing over the wide region of X-ray energy in the PIXE spectrum is very troublesome presence in the peak fitting. In the usual manner, the spectrum of continuous background is predicted as a function of polynomial and is subtracted from the X-ray spectrum. However, the parameters of the polynomial are determined with difficulty in the case that the continuous background exists under many peaks of characteristic X-rays. We calculated the production cross sections of continuous X-rays for several elements on the basis of the theories of quasi-free electron bremsstrahlung (QFEB), secondary electron bremsstrahlung (SEB) and atomic bremsstrahlung (AB), and obtained the continuous X-ray spectrum as a function of atomic number and X-ray energy. X-ray spectra of a standard sample and of a bovine liver sample were analyzed by a pattern analysis method assuming the reference spectra consisting of characteristic X-rays and continuous X-rays for each element. The results of analysis are quite satisfactory. By the present method, the PIXE spectra can be analyzed under little influence of the background subtraction, and it enables us a full auto-analysis of PIXE spectrum.     

Shear deformation behavior of Al–5% Mg in a semi-solid state

Shear tests have been carried out over a wide temperature range of 753–893 K, including temperatures below and above the solidus temperature, for an Al–5 wt% Mg alloy. The deformation behavior in the semi-solid state is divided into two regions; one is in a semi-solid state containing a discontinuous liquid and the other is in a semi-solid state containing a continuous liquid. An analysis of the activation energy suggests that the deformation in the latter region is associated with the lubricated flow. Deformation in the former region is likely to be a transition from the viscous glide creep in the solid state to the lubricated flow in a semi-solid state containing a continuous liquid.     

Room-temperature formation of thermally stable aluminium-rich mesoporous MCM-41

The room-temperature (RT) synthesis of MCM-41 mesoporous compounds with high substitution levels of aluminium (Si / Al = 1.5) is achieved in a minimum time of synthesis. The compound shows similar characteristics to hydrothermally synthesized materials. ²⁷Al NMR study confirms the presence of tetrahedral aluminium in as-synthesized material as well as in the calcined material without observing the presence of octahedral aluminium after calcination. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects and Related Mechanisms of the Senolytic Agent ABT-263 on the Survival of Irradiated A549 and Ca9-22 Cancer Cells

Senolytic agents eliminate senescent cells and are expected to reduce senescent cell-mediated adverse effects in cancer therapy. However, the effects of senolytic agents on the survival of irradiated cancer cells remain unknown. Here, the effects of the senolytic agent ABT-263 on the survival of irradiated A549 and Ca9-22 cancer cells were investigated. ABT-263 was added to the culture medium after irradiation. SA-β-gal activity and cell size, which are hallmarks of cell senescence, were evaluated using a flow cytometer. The colony-forming assay and annexin V staining were performed to test cell survival. We first confirmed that radiation increased the proportion of cells with high SA-β-gal activity and that ABT-263 decreased it. Of note, ABT-263 decreased the survival of irradiated cancer cells and increased the proportion of radiation-induced annexin V⁺ cells. Furthermore, the caspase inhibitor suppressed the ABT-263-induced decrease in the survival of irradiated cells. Intriguingly, ABT-263 decreased the proportion of SA-β-gal low-activity/large cells in the irradiated A549 cells, which was recovered by the caspase inhibitor. Together, these findings suggest that populations maintaining the ability to proliferate existed among the irradiated cancer cells showing senescence-related features and that ABT-263 eliminated the population, which led to decreased survival of irradiated cancer cells.     

Improvement of tracking accuracy of double-column machining center with high-speed and high-acceleration driving

This paper presents the technologies for high-precision machining with high-speed and high-acceleration driving of feed-axis of double-column machining centers. In the proposed approach, linear motors whose stator has no magnet are adopted to the feed-axis to realize the high-speed and high-acceleration driving. In addition, the characteristic of generating little heat is necessary for this linear motor to keep out thermal deformations of the machine structure. In the proposed approach, the force pulsation of linear motor is reduced by arranging magnets and canceling effects of two sliders. As a result, the motor position can be controled with high accuracy. Moreover, the high-acceleration causes deflections of the machine structure such as a column. The deflections cause tracking errors at the cutting point of the tool, even if the motor position follows the position command correctly. Then, we propose to adopt the feedforward compensation based on the measured mechanical deflections. Experimental verifications using MCR-H (double-column machining center) show the significant performance improvement of the proposed method. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Intercalation on Transition Metal Trichalcogenides via a Quasi-Amorphous Phase with 1D Order

Intercalation into 1D transition metal trichalcogenides (TMTs) in which fibers are bonded by a weak van der Waals force can be expected to create various intercalation compounds and develop unique physical properties according to the combination of the host materials and guest ions. However, structural changes via intercalation into 1D TMTs are not as simple as those in 2D transition metal dichalcogenides (TMDs) and are still not understood comprehensively. ZrTe₃: a typical compound with a 1D trigonal prismatic structure, belongs to TMTs. Herein, through the Ag introduction to ZrTe₃ via solid-state intercalation, a novel crystal phase with a 1D octahedral structure and a quasi-amorphous (QA) phase during the structural transition are discovered; the QA phase is a novel state of matter in which long-range order is lost while retaining 1D order. Based on the Ag concentration, the transport properties are flexibly modulated from superconductivity to semiconductivity. Density functional theory calculations indicate the attraction between Ag ions and the pair diffusion due to their attraction. Furthermore, judging the attraction or repulsion between guest ions predicts whether to induce a QA phase or simple lattice expansion like the intercalation into 2D TMDs.     

Green emitting β$\ubeta$-SiAlON:Eu2+ phosphors derived from chemically modified perhydropolysilazanes

We report the first synthesis of β-SiAlON:Eu²⁺ phosphors from single-source precursors, perhydropolysilazane (PHPS), chemically modified with Al(OCH(CH₃)₂)₃, and EuCl₂. The reactions occurring during the precursor synthesis and the subsequent thermal conversion of polymeric precursors into β-SiAlON:Eu²⁺ phosphors have been studied by a complementary set of analytical techniques, including infrared spectroscopy, gas chromatography–mass spectrometry, thermogravimetry–mass spectrometry, X-ray diffraction (XRD), photoluminescence spectroscopy, and scanning electron microscopy. It has been clearly established that Al(OCH(CH₃)₂)₃ immediately reacted with PHPS to afford N–Al bonds at room temperature, whereas N–Eu bond formation was suggested to proceed above 600°C accompanied by the elimination of HCl up to 1000°C in flowing N₂. The subsequent 1800°C-heat treatment for 1 h under an N₂ gas pressure at 980 kPa allowed converting the single-source precursors into fine-grained β-SiAlON:Eu²⁺ phosphors. XRD analysis revealed that the Al/Si of .09 was the critical atomic ratio in the precursor synthesis to afford single-phase β-SiAlON (z = .55). Moreover, Eu²⁺-doping was found to efficiently reduce the carbon impurity in the host β-SiAlON. The polymer-derived β-SiAlON:Eu²⁺ phosphors exhibited green emission under excitation at 460 nm and achieved the highest green emission intensity at the critical dopant Eu²⁺ concentration at 1.48 at%.     

Near-Infrared-Triggered On-Demand Controlled Release of Adeno-Associated Virus from Alginate Hydrogel Microbeads with Heat Transducer for Gene Therapy

Gene therapy using adeno-associated virus (AAV) has potential as a radical treatment modality for genetic diseases such as sensorineural deafness. To establish clinical applications, it is necessary to avoid immune response to AAV by controlled release system of AAV. Here, a near-infrared (NIR)-triggered on-demand AAV release system using alginate hydrogel microbeads with a heat transducer is proposed. By using a centrifuge-based microdroplet shooting device, the microbeads encapsulating AAV with Fe₃O₄ microparticles (Fe₃O₄-MPs) as a heat transducer are fabricated. Fe₃O₄-MPs generated heat by NIR enhanced the diffusion speed of the AAV, resulting in the AAV being released from the microbeads. By irradiating the microbeads encapsulating fluorescent polystyrene nanoparticles (FP-NPs) (viral model) with NIR, the fluorescence intensity decreased only for FP-NPs with a diameter of 20 nm and not for 100 or 200 nm, confirming that this system can release virus with a diameter of several tens of nanometers. By irradiating NIR to the AAV-encapsulating microbeads with Fe₃O₄-MPs, the AAV is released on demand, and gene transfection to cells by AAV is confirmed without loss of viral activity. The NIR-triggered AAV release system proposed in this study increases the number of alternatives for the method of drug release in gene therapy.     

Detection of abnormal fish by image recognition using fine-tuning

Artificial Life and Robotics - Fishermen need to remove abnormal or dead fish for the prevention of viral infection. However, the identification of diseased fish is more ambiguous that the...