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In this study, we found that amylose–poly(tetrahydrofuran) (PTHF) inclusion complexes were formed when a mixture of amylose with PTHF was stirred in 1-butyl-3-methylimidazolium chloride of an ionic...

Ozone has been used as an oxidation agent in various fields and efficient ozone production has been required. Streamer discharges generated with nanosecond pulsed power was applied to produce ozone. When using the smaller diameter of the reactor, ozone tends to concentration increases. However, spark discharges also occurs and prevents to increase of ozone concentration. In order to investigate the cause of the spark discharge, spark discharges inside the reactor was observed. The internal wire electrode oscillated as a string and spark discharges frequently occurred at center of reactor where the separation between electrodes became small. At the time, streamer discharges would not develop adequately in whole of the reactor; ozone concentration was reduced. On the other hand, discharge was stable and ozone concentration was kept constant when the internal electrode was changed from a wire to a stud bolt.

The application area of pulsed power technology has been expanding into biological and medical fields. In particular, nanosecond pulsed electric fields (nsPEFs) could directly act on intercellular components without destruction of cell membrane. Clarification of biological effect of endoplasmic reticulum (ER) stress response by nsPEFs would suggest new methods of prevention or therapy of disorders, such as diabetes and obesity. Activation of ER stress response with nsPEFs was investigated in vitro and in vivo experiments. Skeletal muscle of mice was exposed to nsPEFs in vivo experiment. The cell solutions of HEK293, HeLa and C2C12 were exposed to nsPEFs in vitro experiments. Blumlein-type pulse forming network (B-PFN) was used to apply nsPEFs, whose pulse-width was 80 ns, on them. Phosphorylation of eIF2α was investigated by western blot analysis and RT-quantitative PCR analysis to confirm activation of ER stress response. In vivo experiment, Phosphorylation of eIF2α was confirmed, but it was not strong. In vitro experiment, activation of HeLa cell was confirmed by applying nsPEFs. Therefore it is considered that activation of ER stress response by nsPEFs depends on the type of cells.

Many studies on cancer therapy apply conduct of apoptosis by pulse electric fields have been actively started. In this study, in vivo experiment of applying nanosecond pulse electric fields (nsPEFs) on solid tumors are carried out. To advance this study, we adopt the embryonated chick assay, which can easily prepare a large number of samples for test, compared to typical animal experiments. The tumor cells: EMT6/KU (mouse breast adenocarcinoma cells), were planted with capillary on chorioallantoic membrane in fertilized chicken egg. After four days from this process, nsPEFs of 2ns pulse-width were applied on the solid tumor. The tumors were dissected from eggs after three days from the nsPEFs application and were weighed. The control eggs without nsPEFs application were also processed with the same procedure. Difference of the weights of the pulse-treated and controls tumors was confirmed to be significant by using statistics processing. The weights of the tumors decreased with increase of charging voltage of generator. Tumors treated with nsPEFs exhibited apoptosis by TUNEL staining.

Recently, water pollution is one of environment issues around the world. Consumption of surfactants which is one of organic solvents has increased for industrial and domestic usages, because environmental load of surfactants is lower than that of the other organic solvents. We have studied a water treatment using nanosecond pulsed powers. Discharge plasmas generated by the nanosecond pulsed powers efficiently produce active species which are applicable to water treatments. The water treatment by nanosecond pulsed power utilizes not only the species but also actions of discharges. A water treatment system was developed to increase density of the active species and discharges could strongly affect water. To realize the features, a dielectric barrier in electrodes was adopted for the system to decrease electrode-separation in the reactor in addition to use of nanosecond pulsed powers. The degradation of the surfactant was evaluated by chemical oxygen demand depending on a consumption of potassium permanganate (CODMn) which was widely used for assessments of drainage water in Japan. The initial CODMn was about 80 mg/L. The CODMn of treated solution was decreased mildly for 30 minutes of treatment and then the CODMn increased. The CODMn of the solution treated by pulsed power was approximately 20 mg/L higher than that by only ozone gas generated with an external ozonizer. The difference between the CODMns was caused by the hydrogen peroxide produced by OH radical because of electric discharges in using pulsed power. On the other hand, foaming property, as a behavior of surfactants, reduced faster than the treatment ozone gas generated externally.

The current in a wire array during its exploding phase has been studied. The wire array consisting of many thin wires is used as a plasma source in a z-pinch X-ray radiation system. The current distribution in the exploding wire array plays an important role in producing an initial symmetrical plasma. In the present experiment, four tungsten wires of 0.1 mm in diameter were exploded in a vacuum. The experiment was carried out with an inductive voltage adder pulsed power generator providing a current of 160 kA at quarter period of 1.8 /spl mu/s The currents through and the voltage across the wires were measured simultaneously. It was found that the currents in the wires were inhomogeneous, especially after the wires became plasma. Once the currents became inhomogeneous, the inhomogeneity remained throughout the discharge. It was also studied how the dimensions of the wires affected the homogeneity of the currents. Wires of different lengths or different cross sectional areas resulted in strong inhomogeneities of the currents. The wires with shorter length or smaller cross-sectional area became plasmas earlier than other wires. Thus, the resistances of the wires were not equal. These differences in the resistance caused the inhomogeneity of the currents.

One of the major drivers of pulsed power innovation is ultrawide-band technology. Subnanosecond risetimes with nanosecond or less pulse durations place this technology in a temporal regime that corresponds to microwave frequencies. These ultrawide-band devices have pushed pulsed power technology into a parameter space where there is little published data on breakdown. This paper describes the experimental determination of the Paschen curve for two gases under the application of intense, transient, electric fields. This experiment utilized the Hindenberg series of hydrogen gas switched pulsers at the Air Force Research Laboratory located at Kirtland Air Force Base. The Paschen curves for hydrogen and helium are presented. For subnanosecond risetime pulses, there are typically very few free electrons in the discharge space generated by external radiation sources such as cosmic rays. The occurrence of cosmic ray ionization in the gap is unlikely in such a short period of time. Therefore, electric field emission plays a very important role in these discharges. However, a small number of discharges are effected by ionization from external radiation, with the resulting data lying along classic Paschen curves. As a verification of this effect, an intense continuous ultraviolet (UV) source was utilized for supplying seed electrons and the expected Paschen curves of hydrogen and helium were obtained.

A lens is described that produces a columnar focus comprised of a continuum of focal points at varying distances from the principal plane of the lens aligned along the axis of the lens. The lens refracts an incident wavefront with a focal length that is dependent upon the radial distance from the axis of the lens. The radii of curvature of the primary surface of the lens is dependent upon the desired length of the focal column.

In the performance of intense electromagnetic transient, gaseous breakdown experiments, one parameter of interest is the effective electric field. A method of calculating the effective electric field for an arbitrary electromagnetic pulse is presented. This method is based upon the Laplace transform of the Lorentz force equation. Results from previous efforts are reproduced via this method and compared. Examples are calculated for various electromagnetic transients, most of which have never been calculated before. These examples of effective electric fields are used to generate theoretical Paschen curves, which are compared to experimental results.

Diastereoselective methylation of the enolate generated from various protected 6-oxopipecolic acid esters (3aa-3cd) was studied. The protecting groups on the carboxylic acid and amino groups significantly influenced the trans/cis selectivity in the methylation reaction. The optimal substrate (3ca), bearing benzhydryl ester and carbobenzyloxy moieties gave a trans/cis isomer ratio of ca. 4 : 1. Investigation of the reaction conditions revealed that the reaction solvent, alkylating reagent, and base employed to generate the enolate, were decisive factors for diastereoselectivity. Further optimization of reaction conditions, including the amounts of the reagents and their addition sequence enabled maximization of reaction conversion and minimization of by-products to produce the trans rich 5-methyl-6-oxopipecolic acid ester (4ca) on a large scale.

An efficient synthetic process for the key intermediate of a new peptidomimetic dual metalloprotease inhibitor, ER-40133, was developed. (5R)-Methyl-6-oxopipecolic acid ester (3a), prepared from L-α-aminoadipic acid, was chemoselectively reduced to the protected (5R)-methyl-6-hydroxypipecolic acid ester (4a), followed by treatment with L-cysteine methyl ester to give the linear key intermediate (5a) with the desired configuration. After deprotection of the ester moiety of 5a, the newly generated carboxylic acid group was intramolecularly condensed with the amino group at the thiazolidine ring using ethyl chloroformate in the presence of base to provide [5.7]-bicyclic compound (7a) with the desired configuration in excellent yield. Lastly, the methyl ester of 7a was hydrolyzed under alkaline conditions to afford 8a, a key intermediate for ER-40133.

Water Pollution is one of environment issues around the world. Consumption of surfactants instead of organic solvent has increased for industrial and domestic usages, but the surfactants have environmental load. We have studied a water treatment using nanosecond pulsed powers. Discharge plasmas generated by the nanosecond pulsed powers efficiently produce radicals, as ozone, which are applicable to water treatments. The water treatment by nanosecond pulsed power uses actions of not only radicals but also discharges. A water treatment system was developed to increase radical density and activate the action of discharges. In addition to use of nanosecond pulsed powers, a dielectric barrier in electrodes was adopted for the system to decrease electrode separation in the reactor. Decolorization of indigo carmine solution and decomposition of surfactants solution were tested by using the treatment system. The decolorization was tested to valuate performance of the treatment system by comparison with a previous system. As a result, the indigo carmine solution was decolorized. The decomposition of the surfactant was evaluated by chemical oxygen demand (COD) which was widely used for assessments of drainage water quality. The COD of the surfactant solution was decreased mildly. On the other hands, foaming property, as a behavior of surfactants, remarkably reduced.

Several β-d-ribonucleosides were synthesized in high yields under mild conditions by N-glycosylations of methyl 2,3,5-tri-O-benzoyl-β-d-ribofuranosyl carbonate (1) with trimethylsilylated nucleoside bases in acetonitrile using a catalytic amount of metal iodide such as SnI2, SbI3 or TeI4. A deprotection of N6 -benzoyl group of coupling product took place to a considerable extent when N6 -benzoyl-N6 , N9 -bis(trimethylsilyl)adenine was employed as a nucleoside base using SnI2 or SnCI2 as a catalyst while it was minimized when SbI3 or TeI4 was used. Further, the N-glycosylation of 1 with 7-trimethylsilyltheophylline in the presence of a catalytic amount of metal iodide was more effectively achieved in nitrile solvents other than acetonitrile. #This paper is dedicated to Dr. Yoshihisa Mizuno on the occasion of his 75th birthday.

Fuses, when used as an opening switch, are often connected in parallel to handle large energies. Here, an experiment using two fuses is carried out to understand the behavior of parallel fuses clearly. The waveforms of current flowing through each fuse are different. Unstable behaviors, in which the difference of the currents flowing into the two fuses increases, are observed, and the condition and probability of appearance of the unstable behavior are discussed. The cause of the unstable behavior is that the rate of change of fuse-resistivity with input energy is different depending on the state of the wire. Any differences in initial dimensions of the parallel fuses or any kind of disturbance during the fuse action could immediately trigger off the unstable behavior. >

In ozone production using plasma generated with pulsed power, the concentration of ozone is not high although ozone is produced with high efficiency. Effect of shortening electrode separation of a coaxial reactor was investigated in order to generate ozone in high concentration in using pulsed power. Ozone concentration and yield increased with decreasing diameter of the reactor because spatial density of plasma would become higher. In these reactors, the ozone yield remained in nearly constant value while the ozone concentration increased in proportion to pulse repetition rate. In reactor of 17 mm, saturation tendency and reduction of the concentration were however seen. In this reactor, the ozone concentration decreases with time after reaching a peak value. Spark discharges with short electrode separation caused temperature elevation of electrodes and gases, so that thermal decomposition of ozone molecules occurred. When oxygen gas containing ozone instead of pure oxygen gas flowed into the reactor, rise of the ozone concentration competed with ozone concentration produced with pure ozone gas. The rise showed potential of plasma for ozone production. Ozone with higher concentration could be obtained by the potential of plasma on an appropriate condition.

Bioelectrics has become a notable field of pulsed power application at the present day. Cancer therapy using apoptosis with nanosecond pulsed electric fields (nsPEFs) has been studied in laboratories. We introduced embryonic chick assay to study in vivo. The embryonic chick assay has several advantages and is categorized as in vivo experiment. Many samples can be prepared with low cost by the assay. This study adopted EMT6/KU (mouse breast adenocarcinoma cells) as tumor cells, which formed a solid tumor on the chorioallantoic membrane (CAM) of a fertilized hen egg in the assay. Nanosecond pulsed electric fields with width of 1.5 ns were applied on the solid tumor on CAM with needle electrodes. Stainless wires of 1 mm in diameter were used as the needle electrodes. The two or four needle electrodes were used in this experiment. The solid tumor was dissected and extracted from the egg on a three days after application of nsPEF and was then weighed. The controls of tumor sample were also prepared without nsPEF application. Significance test on the weight of tumors was adopted to determine the effect of nsPEFs application. The difference of weight between the tumor with nsPEF application and control was significantly confirmed. The difference enlarged with the charging voltage of pulsed power generator.

β-D-Ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases by the use of [diphenyltin sulfide/silver salt] or [Lawesson’s reagent/silver salt] combined catalyst system under mild conditions.

Catalytic aldol reactions of several aldehydes with trimethylsilyl enol ethers are effectively performed by combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate (AgClO4) or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.

Catalytic synthesis of several D-ribofuranosides from 2,3,5-tri-O-benzyl-1-O-iodoacetyl-D-ribofuranose and trimethylsilylated nucleophiles such as 3β-cholestanyl trimethylsilyl ether and phenyl trimethylsilyl sulfide is efficiently promoted by tin(II) chloride under mild conditions. When allyltrimethylsilane, azidotrimethylsilane, etc., are used as nucleophiles, combined use of catalytic amounts of SnCl2 and SiCl4 also afforded the corresponding ribofuranosides in good yields.

In using pulsed power, although ozone is produced with high efficiency, the concentration of ozone is not high. Introduction of reactor coupled with a capacitor and use of nanosecond pulsed power transmission technique is considered to improve the ozone concentration. The reactor coupled with a capacitor can suppress incidence of spark discharges between electrodes of the reactor. The concentration of ozone in using the reactor coupled with a capacitor was 1.85 g/Nm3, while that without the coupled capacitor was 1.73 g/Nm3. When pulsed repetition rate of pulsed power was increased, reactor coupled with a capacitor can control the temperature elevation and thermal decomposition of ozone by spark discharges. In the experiment of nanosecond pulsed power transmission technique, although voltage of nanosecond pulse decreases, double stacked pulse, pulse trains and bipolar pulses can be obtained for resistive load. When the decrease of voltage is considered, the observed multiplication ratio by double stacked lines well agrees with 1.2 which can be evaluated. The transmitted pulses through cables arrive successively to the load with time interval of 16 ns for pulse trains and bipolar pulses.

The depletion of fossil fuel is a serious global problem. The development of new biomass fuel, which is not made from foods as corn and sugar cane, is an urgent necessity. For the easiness of the cultivation and the richness for containing fuel, hydrophytic microalga is expected as a crude material for biomass fuel. The manufacturing process is sketchily classified into cultivation, extraction of oil component and refinement of fuel. The manufacturing process without cultivation is, however, inefficient at present. This study applies pulsed power technology to the production process of biomass fuel made from microalga, which is the cultivation and extraction process. Nanosecond pulsed electric fields are applied to the microalga to anticipate increment of cultivation speed and modification of component. In this experiment, the alga density of large number of treated samples was higher than that of negative control samples after seven days of the treatment. The technology to open up pores on cell membrane is called electroporation, and it is important cell control technology in the biotechnology. In another experiment, pulsed power was applied to the alga to improve the efficiency of component extracting process with electroporation. The pulsed powers with different pulse length were used to consider the effect.

Pulse electric fields conduct apoptosis to biological cells. Many studies have started to apply the phenomena to cancer therapy. In this study, we introduce the embryonated chick assay to the experiment applying nanosecond pulse electric fields on tumor. The embryonated chick assay has several advantages in experiments; this experiment is generically classified as in vivo. Many species of virus or rickettsia are available because of the low protective immunity. In some conditions, angiogenesis would be yielded so that the cancer tissue in body was well simulated. To preparation of many specimen materials, with large incubator, is easier than that for laboratory animal such as mice and rats. Nanosecond pulse electric fields (nsPEF) are applied on a tumor on the chorioallantoic membrane in an egg with needle electrodes. A pulsed power generator whose output pulse length is a nanosecond is used in this experiment. The tumor cells: EMT6/KU (mouse breast adenocarcinoma cells) adopted for the experiment are transplanted before several days in advance. The cells form a solid tumor. The needle electrode to apply nsPEF consists of a steeple stainless wire of 1 mm in diameter with a rubber sleeve. The two or four needle electrodes are inserted into the egg through a window on shell so as to tack the tumor in them. The tumors are retrieved from the eggs a few days after nsPEF application and are weighed. The control eggs without nsPEF application are also processed as the same procedure. Rejection-test are used for significant test on application of pulsed electric fields. The significant difference between weight of the tumor with nsPEF application and that of control was confirmed with the significant tests. The difference increased with the charging voltage of pulsed power generator. Another experiment is necessary not only to find the optimal experimental condition but to develop the experimental instruments for therapy.

The application area of pulsed power technology is expanding into biotechnology and green technology. In particular, biological and medical field as sterilization with pulsed electric fields or discharges and electroporation have been studied actively in recent years. It is clear that the pulse electric fields bring some sort of influences to organism. But for now, it is not sufficiently clear what influence appears and how mechanism works on organisms by the pulsed electric fields. To clarify them will prominently develop the biological application area of pulsed power technology. The influences of pulsed electric fields on gene expression of pathogenic bacteria have been studied. Vibrio parahaemolyticus as pathogenic bacteria was selected as an experimental object. The solution whose bacterial density is 109 /ml and volume is 2 ml is applied with 100 or 1000 pulsed electric fields. The expression level of RNAs as VP1680, VP1699, TDH, and RNA16S is analyzed by method of PCR. To apply the pulsed electric fields, a system, consisting of the Blumlein-type pulse forming network (B-PFN) and electrodes chamber, was used. The B-PFN outputs pulses with width of 100 ns in the case of 5 L-C stages. When the separation of the electrodes of chamber was 5 mm, the peak electric fields applied to the solution was evaluated to be approximately from 4 to 14 kV/cm on some experimental conditions. The gene expression of VP1680 and VP1699 increased by comparison with negative controls. On the other hand, the expression of TDH fluctuated. These results would suggest a probability of selective control on gene expression by pulsed electric fields and would develop new application such as functional foods.

Pulsed discharge in water with bubbles is proposed for water treatment including the persistent substance. The persistent substance (chiefly organic substance) is difficult to decompose by natural phenomenon. The humic acid that is a target in this study is one of the persistent substances. A Blumlein type pulse forming network (B-PFN) is provided in the present work. The discharge reactor is a glass cylinder with injection needle - spiral electrodes system. Helium, oxygen and nitrogen are used for the bubbling gas. The process time by pulsed discharge in the nitrogen bubble is shorter than the time by pulsed discharge time in helium, oxygen bubbles. The organic carbon concentration in the humate solution has decreased by the pulsed discharge in the nitrogen bubble. The factor of decomposition of the humate solution is compared with ozone and ultraviolet irradiation.

Catalytic synthesis of β-D-ribofuranosides from C-1 free ribofuranose, 2,3,5-tri-O-benzyl-D-ribofuranose, and alcohols is efficiently performed by combined use of silver salts and Lawesson’s reagent, [2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide], or silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Catalytic stereoselective synthesis of several ribonucleosides from 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl methyl carbonate and trimethylsilylated nucleoside bases is efficiently carried out by combined use of silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Catalytic stereoselective synthesis of 1,2-cis- or 1,2-trans-ribofuranosides from 1-O-iodoacetylribofuranose and alkyl trimethylsilyl ethers is efficiently promoted by combined use of silver salts and lithium perchlorate or diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Catalytic synthesis of several D-ribofuranosides from 2,3,5-tri-O-benzyl-1-O-iodoacetyl-D-ribofuranose and trimethylsilylated nucleophiles such as 3β-cholestanyl trimethylsilyl ether and phenyl trimethylsilyl sulfide is efficiently promoted by tin(II) chloride under mild conditions. When allyltrimethylsilane, azidotrimethylsilane, etc., are used as nucleophiles, combined use of catalytic amounts of SnCl2 and SiCl4 also afforded the corresponding ribofuranosides in good yields.

Catalytic stereoselective synthesis of several ribonucleosides from 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl methyl carbonate and trimethylsilylated nucleoside bases is efficiently carried out by combined use of silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Catalytic aldol reactions of several aldehydes with trimethylsilyl enol ethers are effectively performed by combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate (AgClO4) or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.

Catalytic stereoselective synthesis of 1,2-cis- or 1,2-trans-ribofuranosides from 1-O-iodoacetylribofuranose and alkyl trimethylsilyl ethers is efficiently promoted by combined use of silver salts and lithium perchlorate or diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Catalytic synthesis of β-D-ribofuranosides from C-1 free ribofuranose, 2,3,5-tri-O-benzyl-D-ribofuranose, and alcohols is efficiently performed by combined use of silver salts and Lawesson’s reagent, [2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide], or silver salts and diphenyltin sulfide (Ph2Sn=S) under mild conditions.

Several β-D-ribonucleosides are stereoselectively synthesized in high yields from methyl 2,3,5-tri-O-benzoyl-β-D-ribofuranosyl carbonate and trimethylsilylated nucleoside bases such as pertrimethylsilylated uracil and adenine under mild conditions by using a catalytic amount of tin(II) chloride, a weak Lewis acid.

Several β-d-ribonucleosides were synthesized in high yields under mild conditions by N-glycosylations of methyl 2,3,5-tri-O-benzoyl-β-d-ribofuranosyl carbonate (1) with trimethylsilylated nucleoside bases in acetonitrile using a catalytic amount of metal iodide such as SnI2, SbI3 or TeI4. A deprotection of N6 -benzoyl group of coupling product took place to a considerable extent when N6 -benzoyl-N6 , N9 -bis(trimethylsilyl)adenine was employed as a nucleoside base using SnI2 or SnCI2 as a catalyst while it was minimized when SbI3 or TeI4 was used. Further, the N-glycosylation of 1 with 7-trimethylsilyltheophylline in the presence of a catalytic amount of metal iodide was more effectively achieved in nitrile solvents other than acetonitrile. #This paper is dedicated to Dr. Yoshihisa Mizuno on the occasion of his 75th birthday.

Nitrogen oxides (NOx) are one of the air pollutants that cause acid rain. Although utilization of catalysts is a typical established method of treatment to remove NOx, the catalyst is so expensive that the cost of treatment is high. The efficient treatments using pulsed power, which utilize the pulse streamer discharges, have been studied. We have brought the nanosecond pulsed power to the NOx treatment. More efficient treatment is expected with the high electric fields with a nanosecond pulse width. In using the nanosecond pulsed power, the issue of design and modification of reactors configuration becomes significant. The matching of reactor to the generator output is strict and the behaviors of discharges in the reactors as an electrical circuit are complicated. The reactors with coaxial electrodes were basically adopted and the removal ratios and the efficiencies were evaluated on various reactor configurations, in order to optimize the reactors configuration. The number, connecting method of the reactor chambers and of gas tubing was investigated to improve treatment efficiency in the experiment.

The pulsed power technology is gaining ground on applications to biological field such as sterilization with pulse electric fields or discharges and induction of the apoptosis with pulse electric fields. Under the circumstances, the pulse electric fields clearly have some influence on organism. To figure out the influence and mechanism, we conducted an experiment. The pulse electric fields were applied to the pathogenic bacteria, and manifestation of RNAs which affected pathogenicity was examined. A system was developed to apply the pulsed electric fields to bacteria. The pulsed power generator, which consists of a Blumlein-type pulse forming network (B-PFN), outputs pulses with width of 100 ns in the case of 5 L-C stages. The electrodes chamber was filled with the solution (2 ml) with bacteria. The separation of the electrodes was 5 mm and approximately uniform electric field was applied to the solution. The manifestation of RNAs was analyzed with the method of polymerase chain reaction, PCR. Vibrio parahaemolyticus (RIMD 2210633) was selected to examine. The manifestations of RNAs as VP1699, VP1680, VPA1321, VPA1327, VPA1346, TDH, and RNA16S were examined with the PCR method. Although RNA16S does not become an index for pathogenicity, evaluation of RNA16S implies a survival ratio of the bacteria. The initial density of bacteria solution was regulated to be 109 /ml. The peak voltage was approximately 6, 12 kV and the number of applied pulses was 1000 for each sample. The tendency of increase in manifestation was found by the application of pulse electric fields for VP1699 and VP1680 with relation of TTSS(1).

Nitrogen oxides (NOx) are one of the air pollutants that cause acid rain. While utilization of catalysts is a typical method of NOx treatment to remove, the treatment using pulsed power has been developed. A nanosecond pulsed power generator has been developed and NOx treatment experiment is conducted. As the width of pulsed power shortens, the efficiency of treatment will be improved but the issues in using nanosecond pulses have appeared: difficulties of load matching and optimization of the discharge reactor. Then, the parallel- and serial-connections of reactors are considered. The reactor consists of wire and cylinder electrodes and has a coaxial structure. Efficiency of the parallel connection was higher than the serial connection. In this experimental condition, three parallel reactors yielded the highest efficiency in the all reactor configurations. Since load matching is an important matter for nanosecond pulsed power, the parallel or serial connection would improve the treatment efficiency. The configuration of reactors for high efficiency of NOx treatment will be reported in detail.

The pulsed power generator, named ASO-I, is extremely compact and light in comparison with a conventional pulsed power generator, which consists of a Marx bank and a water pulse forming line. The ASO-I has a two-staged opening switch, consisting of fuses in water and a plasma erosion opening switch, and can be operated hundreds of times a day at an output power of 230 kV and 35 kA. The parallel fuses are effective for power multiplication, and small differences in length of the parallel fuses do not influence the output power. The risetime of current through the short-circuit load decreases with the increase of the gap length of the spark gap, which is placed between the fuses and the load. The plasma erosion opening switch can be operated as a second opening switch, and the risetime of the current through the short-circuit load decreases from 250 to 10 ns. The maximum resistance of the plasma erosion opening switch is 3.5 Omega with an open-circuit load. >

It is difficult to ascertain the detail behavior of multichannel gap switches from experimental studies only. The behavior of multichannel gap switches is investigated by a numerical analysis. The waveforms of the output voltage are numerically obtained and the statistical characteristics of a pulsed power switch are evaluated. The numerical analysis is useful for designing the switches and to investigate the breakdown phenomena.