Effects of Fe3O4 Magnetic Nanoparticles on A549 Cells

Fe₃O₄ magnetic nanoparticles (MgNPs-Fe₃O₄) are widely used in medical applications, including magnetic resonance imaging, drug delivery, and in hyperthermia. However, the same properties that aid their utility in the clinic may potentially induce toxicity. Therefore, the purpose of this study was to investigate the cytotoxicity and genotoxicity of MgNPs-Fe₃O₄ in A549 human lung epithelial cells. MgNPs-Fe₃O₄ caused cell membrane damage, as assessed by the release of lactate dehydrogenase (LDH), only at a high concentration (100 μg/mL); a lower concentration (10 μg/mL) increased the production of reactive oxygen species, increased oxidative damage to DNA, and decreased the level of reduced glutathione. MgNPs-Fe₃O₄ caused a dose-dependent increase in the CD44⁺ fraction of A549 cells. MgNPs-Fe₃O₄ induced the expression of heme oxygenase-1 at a concentration of 1 μg/mL, and in a dose-dependent manner. Despite these effects, MgNPs-Fe₃O₄ had minimal effect on cell viability and elicited only a small increase in the number of cells undergoing apoptosis. Together, these data suggest that MgNPs-Fe₃O₄ exert little or no cytotoxicity until a high exposure level (100 μg/mL) is reached. This dissociation between elevated indices of cell damage and a small effect on cell viability warrants further study.     

KIF2beta, a new kinesin superfamily protein in non-neuronal cells, is associated with lysosomes and may be implicated in their centrifugal translocation

Lysosomes concentrate juxtanuclearly in the region around the microtubule-organizing center by interaction with microtubules. Different experimental and physiological conditions can induce these organelles to move to the cell periphery by a mechanism implying a plus-end-directed microtubule-motor protein (a kinesin-like motor). The responsible kinesin-superfamily protein, however, is unknown. We have identified a new mouse isoform of the kinesin superfamily, KIF2beta, an alternatively spliced isoform of the known, neuronal kinesin, KIF2. Developmental expression pattern and cell-type analysis in vivo and in vitro reveal that KIF2beta is abundant at early developmental stages of the hippocampus but is then downregulated in differentiated neuronal cells, and it is mainly or uniquely expressed in non-neuronal cells while KIF2 remains exclusively neuronal. Electron microscopy of mouse fibroblasts and immunofluorescence of KIF2beta-transiently-transfected fibroblasts show KIF2 and KIF2beta primarily associated with lysosomes, and this association can be disrupted by detergent treatment. In KIF2beta-overexpressing cells, lysosomes (labeled with anti-lysosome-associated membrane protein-1) become abnormally large and peripherally located at some distance from their usual perinuclear positions. Overexpression of KIF2 or KIF2beta does not change the size or distribution of early, late and recycling endosomes nor does overexpression of different kinesin superfamily proteins result in changes in lysosome size or positioning. These results implicate KIF2beta as a motor responsible for the peripheral translocation of lysosomes.     

KBO Orientability

This article presents three new approaches to prove termination of rewrite systems with the Knuth–Bendix order efficiently. The constraints for the weight function and for the precedence are encoded in (pseudo-)propositional logic or linear arithmetic and the resulting formula is tested for satisfiability using dedicated solvers. Any satisfying assignment represents a weight function and a precedence such that the induced Knuth–Bendix order orients the rules of the encoded rewrite system from left to right. This means that in contrast to the dedicated methods our approach does not directly solve the problem but transforms it to equivalent formulations for which sophisticated back-ends exist. In order to make all approaches complete we present a method to compute upper bounds on the weights. Furthermore, our encodings take dependency pairs into account to increase the applicability of the order. The first and third authors are supported by FWF (Austrian Science Fund) project P18763 and the second author is supported by the Grant-in-Aid for Young Scientists 20800022 of the Ministry of Education, Culture, Sports, Science and Technology of Japan.     

Optical wavelet processor by holographic bipolar encoding and joint-transform correlation

A novel optical wavelet processor based on the techniques of the joint-transform correlator and computer-generated holograms is proposed. A coding technique that is a simplified version of Lee's hologram [Appl. Opt. 9, 639 (1970)] is used to represent positive and negative values for the object signal and wavelet functions. We experimentally demonstrate that wavelet transforms of two different daughter wavelet functions can be simultaneously obtained by the appropriate arrangement of the daughter wavelet functions and the object signal on the input plane.     

Excitation of an untilted narrow-wall slot in a rectangularwaveguide by using etched strips on a dielectric plate

We propose a novel excitation technique of an untilted slot in the narrow wall of a rectangular waveguide. The excitation is realized by inserting into the slot a dielectric plate on which there are etched conducting strips. The strip excitation can control the coupling more easily and accurately than a conventional excitation using tilted wires. We analyze the coupling to the slot by using the dyadic Green's function for the waveguide with the dielectric plate, derived by Seki's (1984) virtual cavity method. A double resonance due to the strip and the slot results in large coupling as well as small variation of the phase of the transmitted wave, both over a wide frequency band. Some results are verified by measurements. The coupling can be tuned by varying the distance between the slot and the strip     

Waveguide-fed parallel plate slot array antenna

A novel planar antenna in which radiating slots are arrayed on one side of a square parallel plate waveguide and coupling slots occupy the other side is proposed. The antenna is excited via the coupling slots by a rectangular waveguide. In order to suppress unwanted reflections and to assure the purity of the transverse electromagnetic traveling-wave mode in the parallel plate waveguide, all the slots are arrayed in pairs. An X-band model antenna was fabricated, and uniform aperture illumination was demonstrated with 48% antenna efficiency. These results demonstrate the feasibility of antennas of this type     

A single-layer slotted leaky waveguide array antenna for mobilereception of direct broadcast from satellite

This paper proposes a single-layer slotted leaky waveguide array antenna for mobile DBS reception. A single-layer feed structure is proposed, where the feed waveguide is in the same layer as the radiating waveguides. This results in the simple fabrication of slotted waveguide arrays, suitable for mass production. Short radiating leaky waveguides are used to get a large beam-tilting angle of about 50° for the horizontal installation of the antenna and a beamwidth broad enough to dispense with mechanical steering in the elevation plane. A prototype antenna sized 30 cm by 21 cm has a maximum of 74% efficiency and more than 69% efficiency within the DBS band. It also has a broad l-dB beamwidth of 7.5° in the elevation plane, which enables clear DBS reception by a picture tube display over about one-third the area of Japan without elevation tracking     

Dual-band-rejection filter for distortion reduction in RF transmitters

A novel concept of dual-band-rejection filter (DBRF) is proposed with its circuit synthesis procedure and examples of its realization with dielectric resonators and microstrip resonators. A DBRF can make two closely spaced rejection bands and a passband between them, with lower loss than a bandpass filter having the same number of resonators and the same frequency selectivity just around the passband. The DBRF can be synthesized by applying novel frequency-variable transformations to a prototype LPF, and its physical size can be smaller than a simple cascade of two conventional band-rejection filters with different rejection bands. The DBRF can be especially applicable to distortion reduction filter in RF transmitters.     

Temperature-swing adsorption of proteins in water using N-isopropylacrylamide copolymer gel particles

The adsorption and desorption behaviors of bovine serum albumin (BSA) in water for temperature-responsive polymer gel particles have been investigated by the temperature-swing operation between 298 and 313 K, where the cationic N-isopropylacrylamide (NIPA) gels copolymerized with vinylbenzyl trimethylammonium chloride (VBTA) or 2-(dimethylamino)ethyl methacrylate (DMAEMA) were used. The NIPA-VBTA and the NIPA-DMAEMA copolymer gels adsorbed BSA while the NIPA homopolymer gel hardly adsorbed BSA, indicating that the copolymer gels adsorb BSA through the electrostatic attraction between the positively charged groups in the gels and the negatively charged BSA. The adsorption amounts for the NIPA-DMAEMA gels were smaller than those for the NIPA-VBTA gels. This may be because almost every VBTA group, which is a quaternary ammonium salt, can be positively charged in water, while only some of the tertiary amine DMAEMA groups are protonated in water. Moreover, it was found that both the copolymer gels with a large mesh size of the polymer network repeatedly adsorbed BSA at 298 K and desorbed some of pre-adsorbed BSA at 313 K by the temperature-swing operation. This BSA desorption may result from the decrease of the number of the positively charged groups accessible to BSA due to the shrinking of the constituent polymer chains.