Localised heating of tumours utilising injectable magnetic nanoparticles for hyperthermia cancer therapy

This study reports an investigation of hyperthermia cancer therapy utilising an alternating magnetic field to induce a localised temperature increase on tumours by using injectable magnetic nanoparticles. In-vitro and in-vivo experiments represent the feasibility of hyperthermia cancer therapy. A feedback temperature control system was first developed to keep the nanoparticles at a constant temperature to prevent overheating in the tumours such that a safer and more precise cancer therapy becomes feasible. By using the feedback temperature control system, magnetic nanoparticles can be heated up to the specific constant temperatures, 37, 40, 42, 45, 46 and 47degC, respectively, with a variation less than 0.2degC. With this approach, the in-vitro survival rate of tumour cells at different temperatures can be systematically explored. It was experimentally found that the survival rate of cancer cells can be greatly reduced while CT-26 cancer cells were heated above 45degC. Besides, localised temperatures increase as high as 59.5degC can be successfully generated in rat livers by using the proposed method. Finally, complete regression of tumour was achieved. The developed method used injectable magnetic nanoparticles and may provide a promising approach for hyperthermia cancer therapy.     

Image interpolation using MLP neural network with phase compensation of wavelet coefficients

When interpolating images in the wavelet domain, the main problem is how to estimate the finest detail coefficients. Wavelet coefficients across scales have an interscale dependency, and the dependency varies according to the local energy of the coefficients. This implies the possible existence of functional mappings from one scale to another scale. If we can estimate the mapping parameters from the observed coefficients, then it is possible to predict the finest detail coefficients. In this article, we use the multilayer perceptron (MLP) neural networks to learn a mapping from the coarser scale to the finer scale. When exploiting the MLP neural networks, phase uncertainty, a well-known drawback of wavelet transforms, makes it difficult for the networks to learn the interscale mapping. We solve this location ambiguity by using a phase-shifting filter. After the single-level phase compensation, a wavelet coefficient vector is assigned to one of the energy-dependent classes. Each class has its corresponding network. In the simulation results, we show that the proposed scheme outperforms the previous wavelet-domain interpolation method as well as the conventional spatial domain methods.     

Isolation of Solid Solution Phases in Size‐Controlled LixFePO4 at Room Temperature

State‐of‐the‐art LiFePO₄ technology has now opened the door for lithium ion batteries to take their place in large‐scale applications such as plug‐in hybrid vehicles. A high level of safety, significant cost reduction, and huge power generation are on the verge of being guaranteed for the most advanced energy storage system. The room‐temperature phase diagram is essential to understand the facile electrode reaction of Li_xFePO₄ (0 < x < 1), but it has not been fully understood. Here, intermediate solid solution phases close to x = 0 and x = 1 have been isolated at room temperature. Size‐dependent modification of the phase diagram, as well as the systematic variation of lattice parameters inside the solid‐solution compositional domain closely related to the electrochemical redox potential, are demonstrated. These experimental results reveal that the excess capacity that has been observed above and below the two‐phase equilibrium potential is largely due to the bulk solid solution, and thus support the size‐dependent miscibility gap model.     

Evaluation of lead exposure in workers at secondary lead smelters in South Korea: with focus on activity of erythrocyte pyrimidine 5'-nucleotidase (P5N)

To evaluate lead exposure among secondary lead-smelting workers with a focus on erythrocyte pyrimidine 5'-nucleotidase (P5N) activity, blood lead concentration (PbB), activity of P5N and other biological variables were examined in 88 exposed workers in five secondary lead smelters and in 24 non-exposed workers in Korea. All of the mean values of air lead concentration (PbA) in the three processes, scrap pretreatment, blast furnace smelting, and refining and casting of the secondary lead smelters, markedly exceeded 0.05 mg/m3. In this survey, 29 (97%) of 30 air samples for lead exceeded 0.05 mg/m3. The highest mean PbA and PbB values were found in the section of blast furnace smelting. All of the mean PbB values in all the sections were higher than 30 microg/dl. PbB of 71 (81%) of the 88 exposed workers exceeded 30 microg/dl. In 31 (35%) of the exposed workers, PbB was above 60 microg/dl. Compared with the non-exposed group, zinc protoporphyrin (ZPP) in the exposed group was significantly increased, whereas erythrocyte P5N activity and activity of erythrocyte delta-aminolevulinic acid dehydratase (ALAD) were significantly inhibited. Erythrocyte P5N activity had valid biological correlation with PbB and with other biological variables, such as ALAD activity or ZPP. Lead exposure affected hemoglobin levels via inhibition of P5N activity, as well as the heme biosynthetic pathway, in the high-exposure state.     

Statistical modeling of electrochemical removal of sodium in fermented food composts

Electrochemical removal of sodium ion from fermented food composts was analyzed and statistically modeled by response surface methodology (RSM). Empirical models were developed to describe relationships between the operating variables (operation time, current density and water contents) and three responses (removal efficiency, energy expenditure and energy efficiency). Statistical analysis indicated that operation time and current density have significant effect on all responses. Good agreement between predicted and measured values confirmed the usefulness of the model. The models were verified by additional experimental at optimum conditions.     

Deformation mechanisms of pure Ti during equal channel angular pressing

The microstructural development of commercially pure titanium was investigated to elucidate the mechanisms of grain refinement and strain accommodation during equal channel angular pressing. The samples were processed at 623 K via route C, in which the sample was rotated 180° around its longitudinal axis between the passes. TEM micrographs of the sample undergoing the first pass revealed that the strain imposed by the pressing is accommodated mainly by {1011} deformation twinning. During the second pass, the deformation mechanism was changed to dislocation slip. TEM analysis indicated that the slip system consisted of alternating twin bands containing dislocations ofa slip on a prismatic plane and ofa+c slip on a pyramidal plane. Microstructural evolution in commercially pure titanium subjected to equal channel angular pressing was discussed based on the preferred orientation formed during the first pass and resolved shear stress for the slip systems.     

Physicochemical properties of CWJ-a-5, a new antitumor 3-arylisoquinoline derivative

The compound CWJ-a-5 [1-(4-methylpiperazinyl)-3-phenylisoquinoline hydrochloride] is a novel 3-arylisoquinoline derivative which has exhibited potent antitumor activity. As part of an effort to develop a useful formulation for clinical evaluation of this compound, the aqueous stability of CWJ-a-5 as a function of pH, ionic strength, and temperature, as well as its various physicochemical properties, have been examined. The pKa value obtained by potentiometric titration in methanol-water mixtures was 3.61, at 25 degrees C. The aqueous solubility and the apparent partition coefficient of CWJ-a-5 over the pH range 2.08-9.88 were consistent with those expected of a weak acid of similar pKa value. The degradation of CWJ-a-5 was found to follow apparent first-order kinetics. The pH-rate profiles generated at 80 degrees C were accounted for by acid-catalyzed degradation at low pH and base-catalyzed degradation at high pH. The activation energy was determined as 22.12 kcal/mol for the degradation of CWJ-a-5 in a pH 2.92 solution with a constant ionic strength of 0.2. Increasing the ionic strength up to 0.9 led to a higher degradation rate constant at pH 2.92. However, CWJ-a-5 was very stable even in a pH 2.92 solution, and its shelf-life was calculated to be 2.03 years at 25 degrees C from the Arrhenius plot.     

Hyaluronic acid and silver sulfadiazine-impregnated polyurethane foams for wound dressing application

Five different kinds of PU foam wound dressings were prepared to investigate their wound healing capability. They include (i) PU+silver sulfadiazine (AgSD), (ii) PU+alginate (Al), (iii) PU+Al+AgSD, (iv) PU+hyaluronic acid (HA), and (v) PU+HA+AgSD. Physical properties and in vitro behaviors of AgSD release and fibroblast adhesion on those dressings were evaluated. From the drug release and fibroblast adhesion studies, it was observed that PU foam impregnated with both HA and AgSD shows good drug release behavior and low adhesion of the cells. Furthermore, the HA and AgSD-containing PU foam showed excellent wound healing effect without any inflammation or yellow cluster. The wound size decreased around 77% after 1 week application of that foam dressing onto a rat skin defect.     

Probing lysine acetylation with a modification-specific marker ion using high-performance liquid chromatography/electrospray-mass spectrometry with collision-induced dissociation

Posttranslational acetylation of proteins regulates many diverse functions, including DNA recognition, protein-protein interaction, and protein stability. The identification of enzymes that regulate protein acetylation has revealed broader use of this modification than was previously suspected. In this study, we describe a method for identifying protein acetylation at lysine residues by analysis of digested protein using HPLC/ESI-MS with a new modification-specific marker ion. Collision-induced dissociation with capillary or nano-LC/ESI-TOF-MS was used to obtain a fragment ion useful as a marker for acetylated lysine. Although the acetylated lysine immonium ion at m/z 143.1 has been used as a marker ion for detecting acetylated lysine, it can be confused with internal fragment ion in some peptides, producing false positive results. We have found a novel marker ion at m/z 126.1, which is a further fragment ion induced by the loss of NH3 from the acetylated lysine immonium ions at m/z 143.1. This novel marker ion was found to be more specific and approximately 9 times more sensitive than the immonium ion at m/z 143.1. In addition, no interfering ions for acetylated peptides were found in the extracted ion chromatogram at m/z 126.1. The utility of this method was demonstrated with acetylated cytochrome c as a model compound. After the modification was probed by the new marker ion, the acetylated lysine site was determined by the CID-MS spectrum. This method was applied to identify histone H4 acetylation in HeLa cells treated with trichostatin A. Three protein bands separated by acid-urea-Triton gel electrophoresis were confirmed as tetra, tri, and diacetylated histone H4 at lysines 5, 8, 12, and 16. This method may be useful for assaying for lysine acetylation, which is an important regulatory process for a range of biological functions.     

Viewing-angle enhancement of speckle-reduced volume holographic three-dimensional display by use of integral imaging

In a conventional integral imaging system the viewing angle is limited by the f-number of the microlens. To overcome this limitation we employ a phase-conjugate beam to read out elemental images, which are stored in photorefractive volume holographic storage, while the rotating diffuser reduces the speckle noise. In the proposed system the viewing angle can be enhanced over the f-number limitation. Experimental results and discussions of viewing parameters are presented.