Studies on the synthesis of analgesics. Part 51. Synthesis of 4-(1-oxo-2-isoindolinyl)phenyl derivatives. [Studies on the syntheses of heterocyclic compounds. Part 779]

In order to examine their effect on carrageenin-induced edema in rats, 4-(1-oxo-2-isoindolinyl)-phenyl derivatives were synthesized. 2-Hydroxy-3-[4-(1-oxo-2-isoindolinyl)phenyl]butyramide was found to be more effective than phenylbutazone.     

Biomechanical effects of shock waves onEscherichia coli and λphage DNA

Escherichia coli (recombinant cells) and phage DNA in suspension liquid were exposed to pressure pulses of about 20s duration and amplitude of up to 14 MPa. These pulses were generated by a diaphragmless shock tube. The destruction of cells was monitored by the assay of phenylalanine dehydrogenase leaking from the recombinant cells and was found to increase remarkably at the peak pressure of higher than 12 MPa. A probability relation for the cell destruction expressed as a function of pressure was proposed. It is most likely that there exists a threshold pressure for the cell destruction. Fragmentation effects of shock waves on phage DNA were analyzed by electrophoresis. They were enhanced by increasing the shock wave strength and the number of shots. Probability for the DNA fragmentation as a function of pressure and molecular size was estimated with HPLC. The larger size of the DNA was more easily fragmented. A threshold pressure does not seem to exist for the DNA fragmentation.     

Total Synthesis of Pradimicinone,the Common Aglycon of the Pradimicin–Benanomicin Antibiotics

A benzo[ a ]naphthacenequinone core, an amino acid, and a disaccharide are the constituents of pradimicin–benanomicin antibiotics 1 (R¹=disaccharide), a class of natural products with significant antifungal and anti-HIV activities. The first total synthesis of pradimicinone (benanomicinone, 1 ; R¹=H), the common aglycon of this class of natural products, has now been achieved based on the transmission of chirality during the pinacol cyclization of 2,2′-biaryldicarbaldehydes.     

A Catalytic and Stereoselective Glycosylation with β‐Glycosyl Fluorides

A catalytic and stereoselective glycosylation of several glycosyl acceptors with β‐D ‐glycosyl fluoride was successfully performed in the presence of a catalytic amount of trityl tetrakis(pentafluorophenyl)borate (TrB(C₆F₅)₄) or trifluoromethanesulfonic acid (TfOH). When TrB(C₆F₅)₄ was used as a catalyst in the solvent pivalonitrile/(trifluoromethyl)benzene 1 : 5, the glycosylation proceeded smoothly to afford the glycosides in high yields with high β‐D ‐stereoselectivities (see Table 3). Further, the glycosylation by the armed‐disarmed strategy in the presence of this catalyst was established (see Table 4). Similarly, glycosylation catalyzed by the strong protic acid TfOH afforded the corresponding β‐D ‐glycosides in good‐to‐excellent yields on treating β‐D ‐ glycosyl fluorides having a 2‐O‐benzoyl group with various glycosyl acceptors including thioglycosides (see Tables 6 and 7).     

Statistical Features in High-Frequency Bands of Interictal iEEG Work Efficiently in Identifying the Seizure Onset Zone in Patients with Focal Epilepsy

The design of a computer-aided system for identifying the seizure onset zone (SOZ) from interictal and ictal electroencephalograms (EEGs) is desired by epileptologists. This study aims to introduce the statistical features of high-frequency components (HFCs) in interictal intracranial electroencephalograms (iEEGs) to identify the possible seizure onset zone (SOZ) channels. It is known that the activity of HFCs in interictal iEEGs, including ripple and fast ripple bands, is associated with epileptic seizures. This paper proposes to decompose multi-channel interictal iEEG signals into a number of subbands. For every 20 s segment, twelve features are computed from each subband. A mutual information (MI)-based method with grid search was applied to select the most prominent bands and features. A gradient-boosting decision tree-based algorithm called LightGBM was used to score each segment of the channels and these were averaged together to achieve a final score for each channel. The possible SOZ channels were localized based on the higher value channels. The experimental results with eleven epilepsy patients were tested to observe the efficiency of the proposed design compared to the state-of-the-art methods.     

Widening the range of high-precision quantitative measurement in retardation-modulated differential interference microscope

To realize high-precision and wide-field measurements in retardation-modulated differential interference contrast (RM-DIC) microscope, we developed a new technique to stitch plural images taken by a high-magnification objective lens with attention paid to the high edge detection ability of the RM-DIC microscope. We showed some experimental results with grating samples and made sure that the developed new method had good performance for widening the measurement field of the RM-DIC microscope.     

10 kHz 40 W Ti:sapphire regenerative ring amplifier

A cryogenically cooled Ti:sapphire regenerative ring amplifier was developed as a laser for generating a laser-produced plasma light source. With a 10 kHz 180 W pump laser, the amplifier output is 40 W before compression and 26 W after compression. We believe it to be the current highest average-power output from a single stage Ti:sapphire amplifier. The effective focal length of the thermal lens is measured to be 2.2 m at 100 K for 180 W of pump power. With a 1 m focal length lens placed in the resonator, the effect of a thermal lens on the resonator mode is suppressed. High conversion efficiency is achieved for the whole pumping power range without any additional measures for thermal compensation.     

Conjugative Effect of the Pyridazinone Ring on the Copolymerizabilities of Substituted Pyridazinones

The free-radical copolymerizations of 3(2-p-substituted-phenyl)6-methylpyridazinones (I) and 3(2-methyl)6-substituted-pyridazinones (II) with styrene (M₁) or acrylonitrile (M₁) have been carried out in dimethylformamide (DMF) at 60° C. ρ values were determined by plotting the values of log 1/r₁ against Hammett's a values to be 0.24 for the I-St system and ?0.20 for the I-AN system. In the case of the Il-St system, however, the reactivities were found to be nicely correlated with Otsu's equation, i. e., log 1/r₁ = 0.06 + 4.8 E_R, suggesting that the growing radicals of II are stabilized by the resonance contributions of the substituents of II at their transition states. All these observations are discussed in terms of the conjugative effect of the pyridazinone ring, together with our earlier observations already reported.