Chitosan as a suitable host for sustainable plasticized nanocomposite sodium ion conducting polymer electrolyte in EDLC applications: Structural, ion transport and electrochemical studies

The challenge in front of EDLC device is their low energy density compared to their battery counter parts. In the current study, a green plasticized nanocomposite sodium ion conducting polymer blend electrolytes (PNSPBE) was developed by incorporating plasticized Chitosan (CS) blended with polyvinyl alcohol (PVA), doped with NaBr salt with various concentration of CaTiO3 nanoparticles. The most optimized PNSPBE film was subsequently utilized in an EDLC device to evaluate its effectiveness both as an electrolyte and a separator. Structural and morphological changes were assessed using XRD and SEM techniques. The PNSPBE film demonstrated a peak ionic conductivity of 9.76×10-5 S/cm, as determined through EIS analysis. The dielectric and AC studies provided further confirmation of structural modifications within the sample. Both TNM and LSV analyses affirmed the suitability of the prepared electrolyte for energy device applications, evidenced by its adequate ion transference number and an electrochemical potential window of 2.86 V. Electrochemical properties were assessed via CV and GCD techniques, confirming non-Faradaic ion storage, indicated by the rectangular CV pattern at low scan rates. The parameters associated with the designed EDLC device including specific capacitance, ESR, power density (1950 W/kg) and energy density (12.3 Wh/kg) were determined over 1000 cycles.

Development of a filtered AXUV diode array for X-pinch soft x-ray spectra in the energy range of 1-10 keV

We develop a filtered absolute extreme ultraviolet (AXUV) diode array to measure the time evolution of the soft x-ray spectrum in the energy range of 1-10 keV. AXUV-HS5, the detector, has a fast rise time of 0.7 ns, a wide energy detection range, and high accessibility. We use Geant4 simulations to design an appropriate filter set for flat-and-sharp virtual channels (VCs), where a filter with no spectral edge removes large tails of the response curves. A Levenberg-Marquardt (LM) method, sensitive to the expected spectral function, is improved to reliably generate a continuous radiation spectrum, by utilizing spectral information from the least-squares (LS) method that reconstructs a discrete spectrum with low spectral resolution directly from the VCs. We test the filtered AXUV diode array on an X-pinch device with a peak current of 140 kA at Seoul National University; the array with ten channels is installed in a vacuum chamber. For a two-wire 40 μm stainless steel X-pinch, x-ray power, radiation temperature, and the reconstructed x-ray spectrum are obtained from the filtered AXUV diode array by the combined LS-LM method.

A modular X-pinch device for versatile X-pinch experiments at Seoul National University

This paper describes an X-pinch device recently developed at Seoul National University (SNU). The SNU X-pinch device is designed and fabricated to accommodate various diagnostics as well as conduct versatile experiments. It is easy to change the capacitance of the pulse generator because the capacitor bank has a modular design without insulation oil or gas. This allows us to perform a variety of experiments with a wide capacitance range from 80 to 800 nF. The operating voltage of the SNU X-pinch device is controlled from 20 to 100 kV by adjusting the gas pressure inside a triggered spark-gap switch. Triggering of the spark-gap switch is synchronized with the operation of a pulsed laser to diagnose the X-pinch plasma at the proper time. A large vacuum chamber precisely machined from an aluminum mono-block is attached to the top of the pulse generator. It is designed to accommodate not only various X-pinch loads but also various diagnostic apparatus such as optical components. Initial experiments with the SNU X-pinch device have successfully generated x rays with wires of various materials and sizes. The device will be used not only to explore the dynamics of X-pinch plasmas but also as a test stand for diagnostics of high-energy-density plasmas.

Data analysis scheme for correcting general misalignments of an optics configuration for a voltage measurement system based on the Pockels electro-optic effect

Having a sub-ns response time and not requiring physical contacts to the measurement points, a voltage measurement system based on the Pockels electro-optic effect, referred to as a PE (Pockels effect)-based voltmeter, is widely used for pulsed high voltage devices such as accelerators and X-pinch systems. To correct for the misalignment of a Pockels cell and the transmittance ratio of a beam splitter, a polar-coordinate-based data analysis scheme has been proposed. This scheme also overcomes a limitation on the measurable range of a PE-based voltmeter without ambiguity and can measure the half-wave voltage of a Pockels cell. We present an improved polar-coordinate-based data analysis scheme using an ellipse fitting method, which can correct for misalignments of all the optics components of a PE-based voltmeter while keeping the advantages of the previous scheme. We show the results of the improved data analysis scheme for measuring a slowly modulated voltage up to approximately 5 kV in about 30 s and a pulsed high voltage up to 7 kV with a rise time of less than 20 ns.

Poly(acrylamide-co-acrylic acid) gel polymer electrolyte incorporating with water-soluble sodium sulfide salt for quasi-solid-state quantum dot-sensitized solar cell

Rapid decay of photoanode, leakage from sealant, and evaporation of electrolyte are always the major concerns of quantum dot-sensitized solar cells (QDSCs) based on liquid electrolyte. Subsequently, gel polymer electrolyte (GPE) appears as an attractive solution in addition to lower cost, lighter weight, and flexibility. Poly(acrylamide- co-acrylic acid) (PAAm-PAA) is of special interest to act as a polymer host to entrap liquid electrolyte because it provides high transparency, good gelatinizing properties, and excellent compatibility with the liquid electrolyte. In this work, the electrical and transport properties of PAAm-PAA GPE incorporating with water-soluble sodium sulfide were characterized by impedance spectroscopy. An increment of ionic conductivity was observed with the incorporation of ethylene carbonate (EC) and potassium chloride (KCl). The highest room temperature ionic conductivity of PAAm-PAA GPE is 70.82 mS·cm−1. QDSC based on PAAm-PAA GPE with the composition of 1.3 wt% of KCl, 0.9 wt% of EC, 55.3 wt% of PAAm-PAA, 38.5 wt% of sodium sulfide, and 4.0 wt% of sulfur can present up to 1.80% of light-to-electricity conversion efficiency.

Development of Polymer Blends Based on PVA:POZ with Low Dielectric Constant for Microelectronic Applications

There is a huge request for the development of low dielectric constant polymeric materials for microelectronic applications. In thisstudy, polymer blends based on PVA:POZ with low dielectric constant has been fabricated. The results of XRD indicate that crystalline domain is enhanced at higher POZ concentration. Brilliant phases between spherulitesare attributed to the enhanced crystalline domains at high POZ content. White portions are appeared in SEM images on the surface of PVA:POZ blends. From EDX analysis, these leaked portions are referred to the POZ material. The number and sizes of the white portions were also found to increase with increasing the POZ content. Using electrical equivalent circuits (EEC), electrical impedance plots (Z″ vs Z') are fitted for all the samples. The results of impedance study illustrated that the resistivity of the samples increases with increasing POZ concentration. From dielectric measurements, dielectric constant was found to decrease with the introduction of more POZ into the PVA polymer. It is found to be about 1.68 at 40 wt.% POZ. Insulating materials with low dielectric constant (ε' < 2) are found to be important in the electronics manufacturing, owing to decrease in crosstalk, resistance-capacitance time delay and power dissipation in high-density circuits. Therefore, further investigations concerning the dielectric constant and impedance for all the samples are also carried out. The real and imaginary parts of electric modulus are studied, where minimizing of electrode polarization can be achieved.

Large-scale interaction effects reveal missing heritability in schizophrenia, bipolar disorder and posttraumatic stress disorder

Genetic susceptibility factors behind psychiatric disorders typically contribute small effects individually. A possible explanation for the missing heritability is that the effects of common variants are not only polygenic but also non-additive, appearing only when interactions within large groups are taken into account. Here, we tested this hypothesis for schizophrenia (SZ) and bipolar disorder (BP) disease risks, and identified genetic factors shared with posttraumatic stress disorder (PTSD). When considered independently, few single-nucleotide polymorphisms (SNPs) reached genome-wide significance. In contrast, when SNPs were selected in groups (containing up to thousands each) and the collective effects of all interactions were estimated, the association strength for SZ/BP rose dramatically with a combined sample size of 7187 cases and 8309 controls. We identified a large number of genes and pathways whose association was significant only when interaction effects were included. The gene with highest association was CSMD1, which encodes a negative regulator of complement activation. Pathways for glycosaminoglycan (GAG) synthesis exhibited strong association in multiple contexts. Taken together, highly associated pathways suggested a pathogenesis mechanism where maternal immune activation causes disruption of neurogenesis (compounded by impaired cell cycle, DNA repair and neuronal migration) and deficits in cortical interneurons, leading to symptoms triggered by synaptic pruning. Increased risks arise from GAG deficiencies causing complement activation and excessive microglial action. Analysis of PTSD data sets suggested an etiology common to SZ/BP: interneuron deficiency can also lead to impaired control of fear responses triggered by trauma. We additionally found PTSD risk factors affecting synaptic plasticity and fatty acid signaling, consistent with the fear extinction model. Our results suggest that much of the missing heritability of psychiatric disorders resides in non-additive interaction effects.

Surveillance of the Middle East respiratory syndrome (MERS) coronavirus (CoV) infection in healthcare workers after contact with confirmed MERS patients: incidence and risk factors of MERS-CoV seropositivity

Given the mode of transmission of Middle East respiratory syndrome (MERS), healthcare workers (HCWs) in contact with MERS patients are expected to be at risk of MERS infections. We evaluated the prevalence of MERS coronavirus (CoV) immunoglobulin (Ig) G in HCWs exposed to MERS patients and calculated the incidence of MERS-affected cases in HCWs. We enrolled HCWs from hospitals where confirmed MERS patients had visited. Serum was collected 4 to 6 weeks after the last contact with a confirmed MERS patient. We performed an enzyme-linked immunosorbent assay (ELISA) to screen for the presence of MERS-CoV IgG and an indirect immunofluorescence test (IIFT) to confirm MERS-CoV IgG. We used a questionnaire to collect information regarding the exposure. We calculated the incidence of MERS-affected cases by dividing the sum of PCR-confirmed and serology-confirmed cases by the number of exposed HCWs in participating hospitals. In total, 1169 HCWs in 31 hospitals had contact with 114 MERS patients, and among the HCWs, 15 were PCR-confirmed MERS cases in study hospitals. Serologic analysis was performed for 737 participants. ELISA was positive in five participants and borderline for seven. IIFT was positive for two (0.3%) of these 12 participants. Among the participants who did not use appropriate personal protective equipment (PPE), seropositivity was 0.7% (2/294) compared to 0% (0/443) in cases with appropriate PPE use. The incidence of MERS infection in HCWs was 1.5% (17/1169). The seroprevalence of MERS-CoV IgG among HCWs was higher among participants who did not use appropriate PPE.

Vibrational studies of flexible solid polymer electrolyte based on PCL-EC incorporated with proton conducting NH4SCN

A flexible solid polymer electrolyte (SPE) system based on poly(ε-caprolactone) (PCL), a FDA approved non-toxic and biodegradable material in the effort to lower environmental impact was prepared. Ammonium thiocyanate (NH4SCN) and ethylene carbonate (EC) were incorporated as the source of charge carriers and plasticizing agent, respectively. When 50 wt.% of ethylene carbonate (EC) was added to PCL-NH4SCN system, the conductivity increased by two orders from of 3.94 × 10(-7) Scm(-1) to 3.82 × 10(-5) Scm(-1). Molecular vibrational analysis via infrared spectroscopy had been carried out to study the interaction between EC, PCL and NH4SCN. The relative percentage of free ions, ion pairs and ion aggregates was calculated quantitatively by deconvoluting the SCN(-) stretching mode (2030-2090 cm(-1)). This study provides fundamental insight on how EC influences the free ion dissociation rate and ion mobility. The findings are also in good agreement to conductivity, differential scanning calorimetry and X-ray diffraction results. High dielectric constant value (89.8) of EC had made it an effective ion dissociation agent to dissociate both ion pairs and ion aggregates, thus contributing to higher number density of free ions. The incorporation of EC had made the polymer chains more flexible in expanding amorphous domain. This will facilitate the coupling synergy between ionic motion and polymer segmental motion. Possible new pathway through EC-NH4(+) complex sites for ions to migrate with shorter distance has been anticipated. This implies an easier ion migration route from one complex site to another.

Poly(ε-caprolactone)-based polymer electrolyte for electrical double-layer capacitors

The potential of electrical double-layer capacitors (EDLCs) fabricated from symmetry activated carbon electrodes and poly(ε-caprolactone) (PCL)-based polymer electrolytes (PE) have been studied. PEs that consisted of PCL, ammonium thiocyanate, and ethylene carbonate (EC) were prepared by solution casting. In this system, EC was added as a plasticizing solvent to improve the conductivity. The room temperature ionic conductivity of PE increased from 3.94 × 10−7 S cm−1 to 3.8 × 10−5 S cm−1 at 50 wt% EC. In the structural studies carried out by X-ray diffraction, it was found that addition of EC reduces the degree of crystallinity of the entire system. Temperature-dependent conductivity studies showed that Vogel–Tamman–Fulcher model fits very well with regression value close to unity. This observation demonstrates a close coupling between the ionic motion and the polymer segment mobility. The preliminary result of EDLC cell was evaluated by cyclic voltammetry. The single-electrode specific capacitance of EDLC is obtained to be 42.4 F g−1.

The growth mechanism for silicon oxide nanowires synthesized from an Au nanoparticle/polyimide/Si thin film stack

During pyrolysis of polyimide (PI) thin film, amorphous silicon oxide nanowires (SiO(x)NWs) were produced on a large scale through heat treatment of an Au nanoparticle/PI/Si thin film stack at 1000 °C. It was shown that carbonization of the PI film preceded the nucleation of the SiO(x)NWs. The formation of the SiO(x)NWs was sustained by the oxygen derived from carbonization of the polyimide thin film while Si was provided from the substrate. Au nanoparticles promoted the SiO(x)NW growth by inducing localized melting of the Si substrate and by catalyzing the nanowire growth.

beta-lapachone induces growth inhibition and apoptosis in bladder cancer cells by modulation of Bcl-2 family and activation of caspases

AIM

To study in vitro the molecular mechanism of apoptosis caused by beta-lapachone, a quinone obtained from the bark of the lapacho tree (Tabebuia avellanedae).

MATERIALS AND METHODS

The study was carried out on human bladder carcinoma T24 cell line. Determination of cell viability was done using trypan blue exclusion method, apoptosis quantitative estimation - by DAPI staining and agarose gel electrophoresis for DNA fragmentation. Flow cytometry analysis, RT-PCR and Western blot analysis, colorimetric assay of caspase activity were applied as well.

RESULTS

It was found that in micromolar range of concentrations beta-lapachone inhibited the viability of T24 cells by inducing apoptosis, which could be proved by formation of apoptotic bodies and DNA fragmentation. Treatment of T24 cells with beta-lapachone resulted in a down-regulation of Bcl-2 expression and up-regulation of Bax expression. beta-lapachone-induced apoptosis was also associated with activation of caspase-3 and caspase-9, inhibition of IAP expression, and degradation of poly (ADP-ribose) polymerase, phospholipase C-gamma1 and beta-catenin proteins. At the same time Fas and FasL levels were inhibited upon treatment with beta-lapachone in a concentration-dependent manner.

CONCLUSION

beta-lapachone-induced apoptosis in T24 cells is mediated, at least in part, by the mitochondrial-signaling pathway.

Practical approach to parameter estimation for ASM3+ bio-P module applied to five-stage step-feed EBPR process

Various parameter optimization approaches to a five-stage step-feed EBPR process modeled using the ASM3+bio-P module were examined. Five stoichiometric (Y(STO,NO), Y(H,O2, Y(H,NO,) Y(PAO,O2), Y(PO4)) and seven kinetic parameters (k(STO), eta(NO), b(H), mu(max),PAO, q(PHA), q(PP), mu(max),A) were estimated. The optimization approaches could be classified based on the data sources (batch experiments or CSTR operation data) and the number of target variables used in calculating the objective function. Optimized parameter values obtained by each approach were validated with CSTR operation data that were not used for parameter optimization. The results showed that the parameter optimization only with batch experimental results could not be directly applied to CSTR operation data. ASM3 + bio-P module parameters could be finely optimized only with CSTR operation data when sufficient target variables for objective function calculation were applied. When the number of target variables was increased, prediction performance was significantly improved. Once optimized, the model was able to predict the characteristic features of the five-stage step-feed process; namely, a high PAO yield, fast PAO growth, fast X(pp) storage, slow X(STO) and X(PHA) storage.

Rule-based fuzzy inference system for estimating the influent COD/N ratio and ammonia load to a sequencing batch reactor

A fuzzy inference system using sensor measurements was developed to estimate the influent COD/N ratio and ammonia load. The sensors measured ORP, DO and pH. The sensor profiles had a close relationship with the influent COD/N ratio and ammonia load. To confirm this operational knowledge for constructing a rule set, a correlation analysis was conducted. The results showed that a rule generation method based only on operational knowledge did not generate a sufficiently accurate relationship between sensor measurements and target variables. To compensate for this defect, a decision tree algorithm was used as a standardized method for rule generation. Given a set of inputs, this algorithm was used to determine the output variables. However, the generated rules could not estimate the continuous influent COD/N ratio and ammonia load. Fuzzified rules and the fuzzy inference system were developed to overcome this problem. The fuzzy inference system estimated the influent COD/N ratio and ammonia load quite well. When these results were compared to the results from a predictive polynomial neural network model, the fuzzy inference system was more stable.

Enhancing flexible fiber filter (3FM) performance using in-line coagulation

A new packing for deep bed filtration using Flexible Fibers has been proposed and developed on a very large scale for tertiary treatment of wastewater. The purpose of this study is to check the possibility of using this technology for the production of drinking water from surface water. In this study, the feasibility of the fiber filter application on water treatment was examined and the removal efficiency of fiber filter was improved using an in-line coagulant injection method. The experiments were carried out at pilot scale. The filter was packed with bundles of polyamide fibers with a bed porosity of 93%. Nak-dong River was used as the filter influent water and alum, PSOM, and PAC were used as the coagulants. The coagulants were injected by the in-line injection method. Small dosages (1-5 mg/L) of the polymeric coagulants (PSOM and PAC) showed an increase of removal efficiency compared to the operation without coagulants. Specifically, 1 mg/L of PAC showed the longest filtration time. Considering filtration time, filtrate quality, and filtered volume, the filtration velocity of 120 m/hr was chosen as an optimum value. For long-term operations, the effluent quality was 0.4 NTU and the removal efficiency was stable for the given optimum conditions.

Parameter sensitivity analysis for activated sludge models No. 1 and 3 combined with one-dimensional settling model

The aim of this study was to suggest a sensitivity analysis technique that can reliably predict effluent quality and minimize calibration efforts without being seriously affected by influent composition and parameter uncertainty in the activated sludge models No. 1 (ASM1) and No. 3 (ASM3) with a settling model. The parameter sensitivities for ASM1 and ASM3 were analyzed by three techniques such as SVM-Slope, RVM-SlopeMA, and RVM-AreaCRF. The settling model parameters were also considered. The selected highly sensitive parameters were estimated with a genetic algorithm, and the simulation results were compared as deltaEQ. For ASM1, the SVM-Slope technique proved to be an acceptable approach because it identified consistent sensitive parameter sets and presented smaller deltaEQ under every tested condition. For ASM3, no technique identified consistently sensitive parameters under different conditions. This phenomenon was regarded as the reflection of the high sensitivity of the ASM3 parameters. But it should be noted that the SVM-Slope technique presented reliable deltaEQ under every influent condition. Moreover, it was the simplest and easiest methodology for coding and quantification among those tested. Therefore, it was concluded that the SVM-Slope technique could be a reasonable approach for both ASM1 and ASM3.

Analytical theory of the stochastic dynamics of the power stroke in nonprocessive motor proteins

Statistical distributions of the structural states of individual molecules of nonprocessive motor complexes such as actomyosins are examined theoretically by considering a two-state stochastic model coupled by chemical reactions along the reaction coordinate representing the internal conformational states of the motor. The use of a conformational reaction coordinate allows for the approximation of taking the rate constants as local in their dependence on the reaction coordinate, and yields a simple analytic solution of the stationary states. The approximation is also tested against numerical solutions with a nonlocal form of rate constants. The theory is well-suited for computational treatments based on atomic structures of protein constituents using free energy molecular dynamics simulations. With empirical sets of free energy functions, stationary distributions of forces exerted by a motor head compare well with known experimental data.

Treatment of strong nitrogen swine wastewater in a full-scale sequencing batch reactor

Treatment of swine wastewater containing strong nitrogen was attempted in a full-scale SBR. The strongest swine wastewater was discharged from a slurry-type barn and called swine-slurry wastewater (SSW). Slightly weaker wastewater was produced from a scraper-type barn and called swine-urine wastewater (SUW). TCOD, NH4+-N and TSS in raw SSW were 23,000-72,000 mg/L, 3,500-6,000 mg/L and 17,000-50,000 mg/L, respectively. A whole cycle of SBR consists of 4 sub-cycles with anoxic period of 1 hr and aerobic period of 3 hr. The maximum loading rates of both digested-SSW and SUW were similar to 0.22 kg NH4+-N/m3/day whereas the maximum loading rates of raw SSW was up to 0.35 TN/m3/day on keeping the effluent quality of 60 TN mg/l. The VFAs portion of SCOD in raw SSW was about more than 60%. The VFAs in SUW and digested-SSW were about 22% and 15%, respectively. NH4+-N and PO4(3-)-P in SSW were removed efficiently compared to those in digested-SSW and DUW because SSW had high a C/N ratio and readily biodegradable organic. High concentration of organic was useful to enhance denitrification and P uptake. Also the amount of external carbon for denitrification was reduced to 5% and 10% of those for digested-SSW and SUW.

External carbon feeding strategy for enhancing nitrogen removal in SBR

Effective method for feeding an external carbon source (ECS) in SBR was investigated to enhance denitrification based on modifying the anoxic/aerobic sub-cycle for swine wastewater treatment. The wastewater discharged from the scraper-type barns contains relatively low readily biodegradable organic. Therefore NOx-N was accumulated during repeating sub-cycle in SBR operation. When acetic acid was fed as ECS during the final sub-cycle, the maximum nitrogen removal rate was 0.22 kg N/m3/d. This was due to both less denitrification rate during the sub-cycle period and inhibition of denitrification by pH drop during the final cycle. The pH drop was caused by a large amount of ECS feeding to remove high concentration of NOx-N in the final period. To overcome these limitations and achieve higher nitrogen removal rate, the intermittent ECS feeding method with raw wastewater at every anoxic period was developed. Using the modifying ECS feeding method, the removal rate was increased to 0.45 kg N/m3/d without NOx-N accumulation.

In vitro activity of beta-lactams in combination with other antimicrobial agents against resistant strains of Pseudomonas aeruginosa

Using the chequerboard titration method, the activity in combination of beta-lactams, fluoroquinolones and aminoglycosides was investigated against 24 Pseudomonas aeruginosa isolates resistant to these antibiotics. Synergy was detected with one or more antimicrobial combinations against 15 of 24 (63%) isolates and partial synergy was detected with one or more combinations against all 24 isolates. No antagonism was seen with any combination. Ceftazidime and cefepime with aztreonam, amikacin and isepamicin showed synergy or partial synergy against 12-20 (50-80%) isolates. Imipenem and meropenem with amikacin and isepamicin showed synergy or partial synergy against eight to 12 (33-50%) isolates. The results of this study indicate that against P. aeruginosa, synergy may occur between beta-lactams, fluoroquinolones and aminoglycosides although the strains are resistant to the individual antibiotics.

Simultaneous organic and nitrogen removal from municipal landfill leachate using an anaerobic-aerobic system

An anaerobic-aerobic system including simultaneous methanogenesis and denitrification was introduced to treat organic and nitrogen compounds in immature leachate from a landfill site. Denitrification and methanogenesis were successfully carried out in the anaerobic reactor while the organic removal and nitrification of NH4+,-N were carried out in the aerobic reactor when rich organic substrate was supplied with appropriate hydraulic retention time. The maximum organic removal rate was 15.2 kg COD/m3 d in the anaerobic reactor while the maximum NH4+-N removal rate and maximum nitrification rate were 0.84kg NH4+-N/m3/d and 0.50kg NO3--N/m3/d, respectively, in the aerobic reactor. The pH range for proper nitrification was 6-8.8 in the aerobic reactor. The organic compounds inhibited nitrification so that the organic removal in the anaerobic reactor could enhance the nitrification rate in the following aerobic reactor. The gas production rate was 0.33 m3/kg COD and the biogas compositions of CH4, CO2, and N2 were kept relatively constant, 66-75, 22-32, and 2-3%, respectively.

Freezing and orientational order in weakly anisotropic fluids

A simple theoretical method of studying the effect of weak anisotropy on the freezing of classical fluids is discussed. Free energy of the solid phase is separated into contributions due to the formation of the regular lattice and the remaining orientational part. The former is calculated by the density-functional theory, while a mean-field theory of orientational order is developed for the latter. An application to the freezing of hard dumbbell fluids yields results in good agreement with simulations.

Immunohistochemical detection of galectin-3 in canine gastric carcinomas

Galectin-3 was detected immunohistochemically in nine canine gastric carcinomas. In normal gastric tissue adjacent to the neoplasms, the gastric epithelial cells showed faint immunolabelling for galectin-3, but in all the tumours the neoplastic cells showed moderate to strong immunolabelling. Galectin-3 was localized in the cytoplasm of the normal mucosal cells, whereas it was found in both the cytoplasm and the nucleus of the neoplastic cells. Positive cells typically exhibited dark brown coloration of the nucleus or cytoplasm, without background labelling. The results suggest that galactin-3 has a pathophysiological role in canine gastric carcinoma.

Evaluation of pH inhibition effect on activated sludge by the pseudo toxic concentration (CPT) concept model

It is generally accepted that the inhibition effect of pH on activated sludge follows the non-competitive inhibition kinetics. But the non-competitive inhibition kinetic equation cannot be directly applied to pH inhibition, due to the difficulty in quantification of pH as a term of inhibitor concentration. So, many empirical equations were developed especially for acidic condition to describe pH inhibition effect. In this research, the pseudo toxic concentration (CPT) concept model to quantify pH inhibition effect on activated sludge was proposed and compared with other existed models. Prediction of performance, presented by Prediction Accuracy and Prediction Accuracy Index, showed that the CPT concept model can explain the reduction of the maximum specific growth rate (mu max) more accurately than any other models do at a wide range of pH. The CPT concept model was applicable not only to activated sludge but also to specific microorganism groups, such as nitrifier, less acidophilic species and nitrifying biofilm.

No significant correlation exists between core promoter mutations, viral replication, and liver damage in chronic hepatitis B infection

Hepatitis B virus (HBV) core promoter mutants have been proposed to contribute to severe liver damage by increasing viral loads, but this has not yet been clearly shown. To examine the effects of core promoter mutants on viral load and liver damage, we first developed a polymerase chain reaction (PCR)-based semiquantitative HBV DNA detection method with a high sensitivity (able to detect as low as 10(3) molecules/mL). Then we cloned 12 predominant core promoter mutants from 41 chronic hepatitis B patients. The in vitro promoter and replication activities of these mutants were similar to those of wild-type virus. However, viral load was highly variable, and this was dependent on individual patients rather than mutant type. In addition, there was no mutant type that showed any unique correlation with alanine transaminase (ALT) levels. Viral load was not significantly correlated with ALT level in both cross-sectional and longitudinal studies. Quantitation of HBV levels also revealed no clear correlation between hepatitis B e antigen (HBeAg) status and viral load. Taken together, these results indicated that the replication activity of core promoter mutants has little effect on viral load, and that viral load does not correlate with the severity of liver damage or with HBeAg status.

Generalized atrophic benign epidermolysis bullosa--poor prognosis associated with chronic renal failure

Generalized atrophic benign epidermolysis bullosa (GABEB) is an autosomal recessive form of junctional epidermolysis bullosa, with milder clinical features than the Herlitz subtype. A 25-year-old man presented with the clinical and histological findings of GABEB. At the initial visit, laboratory tests revealed that he also had chronic renal failure (CRF). Usually, GABEB has a good prognosis. However, in this case, the patient had CRF as an associated complication. He died of an intracranial haemorrhage combined with sepsis after 3 weeks of hospitalization. This case suggests that renal complications can occur in this relatively mild form of epidermolysis bullosa, and may contribute to morbidity and premature mortality.

Anticancer activity of hydrophobic peptides from soy proteins

An anticancer peptide from soy protein was purified and isolated. Defatted soy protein was hydrolyzed with thermoase and hydrophobic peptides were extracted with ethanol. The peptide extract was fractionated by XAD-2 hydrophobic, gel filtration chromatography, and different C18 HPLCs. Anticancer activity of each fraction was assayed by measuring in vitro cytotoxicity on P388D1, a mouse monocyte macrophage cell line. IC50 value of a peptide fraction from Sephadex G-25 chromatography was 0.16 mg/ml. This peptide fraction at 1 mg/ml significantly affected cell cycle progression by arresting P388D1 at G2/M phases. Finally purified peptide from analytical C18 HPLC was nonapeptide of which molecular weight was 1157 Da and the sequence was X-Met-Leu-Pro-Ser-Tye-Ser-Pro-Tyr.

Pylephlebitis associated with appendicitis

Pylephlebitis usually occurs secondary to infection in the region drained by the portal venous system. A most common antesecent focus of infection is diverticulitis and the most common blood isolate is E. coli (54%), followed by Proteus mirabilis (23%). Overall mortality is 32% and most of the patients who had died had severe sepsis prior to the initiation of antibiotic therapy. We describe a case of pylephlebitis which had appendicitis and consequent septic thrombosis of the portal vein and its branches, with dissemination of infection to the liver. The patient had recovered due to timely antibiotic treatment alone and resulted in complete resolution. Early diagnosis and treatment are basic to a favorable clinical course.

Heterogeneous HBV mutants coexist in Korean hepatitis B patients

Although many hepatitis B virus (HBV) mutants have been found in all open reading frames since the precore defective mutant was initially reported, systematic investigations of diverse HBV mutant populations in hepatitis B patients have not been performed. Therefore, we examined whether heterogeneous mutant populations simultaneously exist in Korean hepatitis B patients. In order to detect hepatitis B virus mutants, we amplified a conserved core region and a surface antigen region of HBV DNA by PCR from sera of 27 Korean chronic hepatitis B patients, and then performed single strand conformational polymorphism analysis followed by DNA sequencing analysis. The results showed that heterogeneous HBV mutants in both regions were present in a single as well as in various hepatitis B patients. Sequence analysis revealed a defective interfering particle with missense mutation in the core region. We also found that two subtypes of adr and adw coexisted in a single patient. In addition, a point mutation causing a stop codon in the surface antigen region was observed. We are further analyzing the clinical implications of HBV mutants to identify their roles in the pathogenesis of chronic hepatic disorders induced by HBV.

307-bp fragment in HOXA7 upstream sequence is sufficient for anterior boundary formation

The HOX genes are expressed in a positionally and temporally restricted manner involving anteroposterior axial pattern formation during early embryogenesis. Previously, we studied the sequence and function of an upstream regulatory region of the human HOXA7 gene. To identify a critical cis-acting element, a deletion analysis was performed along the human control region (HCR) (about 1.1 kb), which was sufficient for setting the anterior boundary of expression in transgenic mice. We demonstrated that a 307-bp control region contains a cis-acting element(s) specifying an anterior boundary as well as a dorsal-ventral restriction in the neural tube at day 12.5 postconception (p.c.). The distinct anterior limit of expression was noted at the level of C7/T1 in the neural tube and spinal ganglia. In addition, our deletion experiments revealed that the HCR consisted of several cis-acting elements which were individually capable of driving regionally restricted expression patterns in the neural tube and limb buds.

Primers determine the sensitivity of PCR-mediated hepatitis B virus DNA detection and pretreatment of PCR mixture with 8-methoxypsoralen eliminates false-positive results

Most methods for the diagnosis of hepatitis B virus (HBV) infection largely depend on viral DNA detection by polymerase chain reaction (PCR) or radioimmunological assay of viral antigens or antibodies. The quality assurance program recently established in Europe reported that PCR-mediated HBV DNA detection methods used in many laboratories produced a high rate of false-positive and false-negative results. Thus, we attempted to improve the conditions of current PCR methods for detection of HBV DNA. In the present study, we applied a recently developed method of releasing HBV DNA from virion by NaOH treatment of patient serum. Using four different primer sets specific to the HBV core region, we found that the sensitivity of first-round PCR can be improved by more than two orders of magnitude depending on the primers. The second round of PCR using nested primers was sensitive enough to detect up to 10(-6) pg of the HBV DNA, which is equivalent to approximately 3 copies of the HBV genome. Among the approximately 800 HBV-infected patient sera investigated in our laboratory, more than 60% of the tested samples gave positive results in the first-round PCR. The rate of positive results obtained using our experimental conditions is very high in comparison with other reports. The reamplification of the first-round PCR reaction mixture with the nested primers produced practically 100% positive results. For diagnosis of HBV infection, we routinely used 1 microliter of patient serum, which was found to be optimum in our laboratory. Surprisingly, from 20% of our positive results, even serum diluted to 1/100 (0.01 microliter) produced a stronger signal than 1 microliter. This observation suggests that direct PCR amplification of HBV DNA released from serum by NaOH treatment has to be compensated by other DNA detection methods for correct quantitation. In order to eliminate the false positive signal resulting from the carry-over due to massive screening of a large number of samples, PCR reaction mixture containing 8-methoxypsoralen was exposed to ultraviolet light prior to thermal cycle amplification. This exercise did not decrease the sensitivity of the detection method, but almost completely removed the false positive results caused by contaminated templates. We are in the process of improving PCR-mediated HBV DNA detection methods to attain more reliable and easily applicable methods.

Carbohydrate-binding protein 35 is the major cell-surface laminin-binding protein in colon carcinoma

The interaction of tumor cells with laminin is thought to be critical in invasion and metastasis. We found that an endogenous lectin, carbohydrate-binding protein 35 (CBP-35), is the major laminin-binding protein on human colon carcinoma cells and that its surface expression suggests involvement in metastasis. We identified CBP-35 by laminin-affinity chromatography and immunoblotting. Surface expression of CBP-35 on eight human colon carcinoma cell lines was compared by flow cytometry. Poorly differentiated cell lines and DLD-2, a signet-ring carcinoma cell line, expressed more surface CBP-35 than well-differentiated cell lines. Poorly differentiated cell lines and DLD-2 are characterized as aggressive cell lines because they adhere to and invade through reconstituted basement membrane significantly better than well-differentiated cell lines. These data suggest that CBP-35 is involved in tumor cell-basement membrane interactions and that an increase in CBP-35 surface expression may facilitate metastatic potential of colon carcinoma cells.

Carbohydrate-binding protein 35 (Mac-2), a laminin-binding lectin, forms functional dimers using cysteine 186

Carbohydrate-binding protein 35 (CBP35), also known as the macrophage surface antigen Mac-2, is a lactosamine-specific lectin whose extracellular properties include the ability to agglutinate cells and to bind avidly to the basement membrane glycoprotein laminin. Although these and other properties would be facilitated by dimerization of this lectin, previous studies have argued against multimeric forms of this protein. We report here that macrophage CBP35, purified by laminin affinity chromatography, exists as several distinct species (Mr 35,000, 67,000, and 80,000) when analyzed under non-reducing conditions. This unexpected finding prompted us to study the biochemistry of multimerization using recombinant CBP35 (rCBP35). rCBP35 expressed in Escherichia coli forms disulfide-linked homodimers (Mr 67,000). The dimeric form of CBP35 binds to laminin with higher affinity than does monomer and by a lactosamine-dependent mechanism. Site-directed mutagenesis indicated that cysteine 186, the single cysteine residue in CBP35, is required for dimerization. These results raise the possibility that homo- and heterodimeric forms of CBP35 contribute to its postulated functions in cell-matrix interactions and growth regulation.

An environmental research on trace elements in freshwater fish by neutron activation analysis

For a case study of environmental contamination, radiochemical activation analysis has been applied to the crucians collected in the Han River. Sixteen trace elements (Hg, Cd, As, Br, Cu, Na, K, Se, Cr, Hf, Rb, Fe, Zn, Co, La, and Cs) were separated into three groups using distillation and diethyldithiocarbamate extraction methods, and their contents were determined by a single comparator method. Compared with the values 15 years ago, the values for mercury and cadmium have been drastically decreased at the middle and lower part of the river, but no typical change is found in other elements.

The major non-integrin laminin binding protein of macrophages is identical to carbohydrate binding protein 35 (Mac-2)

Current data indicate that cell adhesion to laminin, the major basement membrane glycoprotein, is mediated by specific integrins, a family of adhesion receptors. In addition, most cell types express a complement of high affinity non-integrin laminin binding proteins (LBPs). Despite considerable effort, the function of these LBPs has not been elucidated. We report here that the major non-integrin LBP of murine macrophages exhibits an Mr of 35,000 and is expressed on the cell surface. Protein microsequencing data revealed that this protein is identical to carbohydrate binding protein 35. This murine galactose-specific lectin is the macrophage antigen Mac-2. Thus, these data suggest that the non-integrin LBPs may contribute to laminin adhesion by a mechanism involving protein-carbohydrate interactions.