Thermally decomposable phosphonate ester polymer gels

A polymerizable dimethacryloyl vinylphosphonate (DMVP) was developed as a novel crosslinking agent by esterification of vinylphosphonic acid and methacryloyl chloride in the presence of triethylamine. Then, poly(DMVP) (PDMVP) was generated by bulk polymerization solution at 30, 45, and 80 °C in the presence of a radical initiator. The resultant PDMVP, polymerized at 45 and 80 °C, could be dissolved in acetone, water, and N-methylpyrrolidone. However, PDMVP obtained at 30 °C showed to be insoluble in such solvents and became a gel instead. It was found that the formed gel was soluble when heating due to hydrolysis of the ester bonds in the polymer. Evidence was presented showing the thermal decomposition behavior of the PDMVP gel, which showed an irreversible solid-to-liquid phase transition.     

Promotion of plant growth under low temperature by ozonated water at low concentration in komatsuna (Brassica rapa L. perviridis Group)

Ozonated water (OW) effects at low concentration on plant growth of komatsuna (Brassica rapa L. var. perviridis) were investigated in growth chambers under ambient or low temperature. Although there was no difference in plant growth between OW and tap water treatments under ambient temperature, plant growth was promoted by OW treatment under low temperature. Nitrate content per plant was similar between the treatments. Soluble sugar and L-ascorbic acid (L-AA) contents were higher in OW treatment. Thus, promotion of plant growth by OW treatment under low temperature could be related to antioxidant ability due to increased L-AA.     

Biosynthetic Gene Cluster for Surugamide A Encompasses an Unrelated Decapeptide,Surugamide F

Genome mining is a powerful method for finding novel secondary metabolites. In our study on the biosynthetic gene cluster for the cyclic octapeptides surugamides A–E (inhibitors of cathepsin B), we found a putative gene cluster consisting of four successive non‐ribosomal peptide synthetase (NRPS) genes, surA, surB, surC, and surD. Prediction of amino acid sequence based on the NRPSs and gene inactivation revealed that surugamides A–E are produced by two NRPS genes, surA and surD, which were separated by two NRPS genes, surB and surC. The latter genes are responsible for the biosynthesis of an unrelated peptide, surugamide F. The pattern of intercalation observed in the sur genes is unprecedented. The structure of surugamide F, a linear decapeptide containing one 3‐amino‐2‐methylpropionic acid (AMPA) residue, was determined by spectroscopic methods and was confirmed by solid‐phase peptide synthesis.     

Carbon-coated anatase: the role of the carbon layer for photocatalytic performance

Carbon-coated anatase-type TiO₂ was prepared by the heat treatment of powder mixtures of photocatalyst TiO₂ (ST-01) with different carbon precursors, poly(vinyl alcohol), hydroxyl propyl cellulose and poly(ethylene terephthalate), at a temperature between 700 and 900 °C for 1 h in an Ar gas flow. Since the carbon layers formed on the TiO₂ particles were porous, the samples prepared showed a high adsorptivity, in addition to the photoactivity of TiO₂. The carbon coating was shown to suppress the phase transition from photoactive anatase to much less active rutile, but seemed to reduce the amount of UV radiation reaching the surface of the TiO₂ particles. A balance among different factors controlled by the carbon layer on the TiO₂ particles was required to get high photocatalytic performance, i.e., high rate constant for the photodecomposition of methylene blue. On the sample prepared at 850 °C with a carbon content of about 3.5 wt%, the highest rate constant in the present work was obtained, in which the transition from anatase to rutile was suppressed and carbon layer was thin enough to transmit UV rays.     

Segmentation of plant hairy roots promotes lateral root emergence and subsequent growth

The influence of root cutting on the emergence of lateral roots was investigated in the cultures of horseradish and madder hairy roots. The original hairy roots prepared for inoculation were cut at various distances from the tips and the resultant segments were cultivated in flasks. It was found that lateral roots very frequently emerged from the segments, depending on the longitudinal positions at which the segments were obtained. To attain the effective growth, cultivation of madder hairy roots with root cutting performed twice at 0 and 360 h was conducted. The emergence of lateral roots facilitated the growth of hairy roots owing to an increase in the number of growing points (GPs). The dry cell mass concentration and the number of GPs were 9.6 kg/m3 and 1.9 x 10(7)/m3 at 672 h of culture time, which were 3.6 and 4.9 times higher, respectively, than those in the control culture without the operation.     

High definition television systems

High definition television (HDTV) services will play the most important role in the digital television systems for the future. HDTV is already broadcast daily in Japan and advanced television (ATV) standards will soon be established in the US. The hardware systems for two HDTV systems, the 1125/60 and 1250/50 systems, have already been developed. Their outlines are described in the paper. Signal processing of HDTV is mainly carried out by digital methods on both the studio and receiver sides. The principles of processing are the same as for conventional television but the higher clock frequency and larger quantity of information require more sophisticated hardware. Digital signal processing methods are the key technology in HDTV broadcasting systems regardless of whether modulation is analog or digital. Some broadcasting systems are already practical use while others, are experimental. The author discusses these systems. The aim of the article is to present a global scope of the HDTV technology     

Turn-off switching analysis considering dynamic avalanche effect for low turn-off loss high-voltage IGBTs

An avalanche generation phenomenon has a large influence on turn-off switching loss and reverse-biased safe operating area of high-voltage insulated gate bipolar transistors (IGBTs). The purpose of this paper is to clarify the correlation between the avalanche multiplication phenomenon and the turn-off characteristics. We introduce a turn-off switching analytical model of IGBTs that considers the avalanche multiplication effect. It is concluded that the criterion of dynamic avalanche depends on the gate resistance. In the case of 4.5-kV IGBTs, the gate resistance of more than 200 /spl Omega//spl middot/cm/sup 2/ is needed to suppress the dynamic avalanche generation under a clumped inductive load circuit. On the contrary, the turn-off switching loss increases in the case that the gate resistance R/sub G/ is increased to more than approximately 100 /spl Omega//spl middot/cm/sup 2/. Theses results show that to realize low turn-off switching loss, it is necessary to ensure that the gate resistance is below a constant value, such as 100 /spl Omega//spl middot/cm/sup 2/. However, at high current density, such as 80 A/cm/sup 2/, the dynamic avalanche will generate under such small gate resistance condition. Therefore, it is important to develop IGBTs without destruction even under the condition of dynamic avalanche generation.     

Predictors for the massive thrombi occurring in the right coronary artery related to acute myocardial infarction

Acute myocardial infarction (AMI) related to the right coronary artery (RCA) is associated with a lower reperfusion rate and higher reocclusion rate in the acute phase than AMI related to the left coronary artery. The greater susceptibility of the RCA to development of large thrombi makes successful reperfusion more difficult to achieve. This study investigated predictive factors for massive thrombus in the RCA before the selection of the treatment to achieve better rates of reperfusion. We classified 51 patients with AMI related to RCA into the massive (linear intraluminal radiolucency > 3 cm) thrombus group (9 patients) and the non-massive thrombus group (42 patients). 1) History: Patients in the massive thrombus group had a greater incidence of hypertension than the non-massive thrombus group, with more left ventricular hypertrophy (p < 0.05). There were no significant differences in other coronary risk factors. 2) RCA morphology: The maximum RCA diameter was significantly greater in the massive thrombus group than that in the non-massive thrombus group [proximal to the right ventricular branch, 4.2 vs 3.2 mm (median); distal to the right ventricular branch, 4.2 vs 3.4 mm, p < 0.05]. 3) Conditions of onset: The elapsed time was significantly longer in the massive thrombus group (15 hours) than that in the non-massive thrombus group (2.5 hours, p < 0.05). More massive thrombus cases were observed in summer (p < 0.05), but there was no evident correlation between massive thrombus formation and the onset time of day, weather, Hct and coagulation factor at the onset, left ventricular ejection fraction or left ventricular end-diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Laparoscopic cholecystectomy using the abdominal wall lift in a cardiac patient

We present a case report of a patient with impaired cardiac function after aortic valve replacement and open mitral commissurotomy who underwent a laparoscopic cholecystectomy for cholecystolithiasis. In preventing reduced cardiac output due to pneumoperitoneum, the laparoscopic operative procedure was performed using the abdominal wall lift. Cardiac function was continuously evaluated by transesophageal echocardiographic examination and remained stable during the surgery. Because of the patient's co-existing chronic atrial fibrillation and prosthetic aortic valve, perioperative anticoagulation management was carried out. The patient's post-operative course was uneventful, and he was discharged on the 7th post-operative day.