2,003 research outputs found
Studies on the oxidation of hexamethylbenzene 2: Preparation of dimethylpyromellitic acid
Hexamethylbenzene (HMB) was difficult to be oxidized with an alkaline potassium permanganate solution, since HMB was insoluble in an aqueous alkaline solution. But, when HMB was warmed with 50% nitric acid for a short time, and then treated with aqueous potassium permanganate, the reaction occurred readily and dimethylpyromellitic acid was obtained. When HMB was warmed with 50% nitric acid for 1 to 2 minutes, a yellow material was produced, which was soluble in hot aqueous potassium hydroxide, though free from carboxylic acids. It contained a little amount of bis-(nitromethyl)prehnitene and several unknown compounds. Further, the heat stability of polyimide prepared by the reaction of tetramethyldimethylpyromellitate with 4,4 prime-diaminodiphenylmethane turned out to be nearly equal to that of polyimide prepared from tetramethylpyromellitate
Studies on the oxidation of hexamethylbenzene 1: Oxidation of hexamethylbenzene with nitric acid
The oxidative reaction of hexamethylbenzene (HMB) with nitric acid was studied, and the hitherto unknown polymethylbenzenepolycarboxylic acids were isolated: tetramethylphthalic anhydride, tetramethylisophthalic acid, 1,3,5-, 1,2,4- and 1,2,3-trimethylbenzenetricarboxylic acids. When HMB was warmed with 50% nitric acid at about 80 C, tetramethylphthalic anhydride and tetramethylisophthalic acid were initially produced. The continued reaction led to the production of trimethylbenzenetricarboxylic acids, but only slight amounts of dimethylbenzenetetracarboxylic acids were detected in the reaction mixture. Whereas tetramethylphthalic anydride and tetramethylisophthalic acid were obtained, pentamethylbenzoic acid, a possible precursor of them, was scarcely produced. On the other hand, a yellow material extracted with ether from the initial reaction mixture contained bis-(nitromethyl)prehnitene (CH3)4C6(CH2NO2)2, which was easily converted into the phthalic anhydride
Proper-time Resolution Function for Measurement of Time Evolution of B Mesons at the KEK B-Factory
The proper-time resolution function for the measurement of the time evolution
of B mesons with the Belle detector at KEKB is studied in detail. The obtained
resolution function is applied to the measurement of B meson lifetimes, the
B0-B0bar oscillation frequency and time-dependent CP asymmetries.Comment: 25 pages, 18 figures, to be published in NIM A, replaced with revised
versio
Biological Characters of 6-Deoxy-6-[18F]Fluoro-D-Galactose
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Effects of ethyl-esterization, chain-lengths, unsaturation degrees, and hyperthermia on carcinostatic effect of omega-hydroxylated fatty acids
Aim: To evaluate promotive effect of hyperthermia on the carcinostatic activity of synthesized omega-hydroxy fatty acids (wHFAs) and their ethylesters agaist Ehrlich ascites tumor (EAT) cells. Methods: EAT cells were cultured with either wHFAs or their ethylester derivatives in a water bath at either 37 °C or 42 °C for 30 min, followed by incubation in a CO2 incubator for 20 or 72 h. Mitochondrial dehydrogenase-based WST-1 assay and trypan blue dye exclusion assay were then conducted after incubation. Morphological changes were observed by scanning electron microscopy (SEM). Results: Omega-HFA having a saturated 16-carbon straight-chain (wH16:0) was the most carcinostatic (at 37 °C – viability level: 60.0%; at 42 °C – 49.6% (WST-1)) among saturated and unsaturated wHFAs with 12, 15 or 16 carbon atoms, when administrated to EAT cells at 100 µM for 20 h. Carcinostatic activity was markedly enhanced by ethyl-esterization of saturated fatty acids, such as wH16:0 (at 37 °C – 42.3%; at 42 °C – 11.2% , ibid) and wH15:0 (at 37 °C – 74.6%; at 42 °C – 25.3% , ibid), and their unsaturated counterparts were extremely effective only in combination with hyperthermia. Prolongation of the incubation period to 72 h at the same concentration increased appreciably their carcinostatic effect (wH16:0 ethylesther: 1.3%; wH15:0 ethylesther: 8.0%). These values were also supported by dye exclusion assay. The carcinostatic activity enhanced more markedly by hyperthermia (1.2%; 2.1%, ibid). SEM shows that wH16:0 ethylester-exposed EAT cells underwent extensive injury, such as deformation of cell structure or disappearance of microvilli. Conclusions: wH16:0 ethylester possesses high carcinostatic activity in vitro in combination with hyperthermia and may be utilized as potent anticancer therapeutic agent.Цель: проанализировать усиливающий эффект гипертермии на канцеростатическую активность синтезированных омегагидроксилированных
жирных кислот (HFAs) и их этиловых эфиров по отноению к клеткам асцитной опухоли рлиха
(EAT). Методы: клетки EAT инкубировали с HFAs или их этилэфирными производными на водной ане при 37 ° или
42 ° в течение 30 мин с дальнейим культивированием в 2
инкубаторе на протяжении 20 или 72 ч, после чего анализировали
жизнеспособность клеток методами анализа WST-1, основанного на активности митохондриальных дегидрогеназ, и по
включению трипанового синего. Морфологические изменения клеток определяли с использованием сканирующей электронной
микроскопии. Результаты: при культивации клеток EAT в присутствии 100 M соединений в течение 20 ч омега-HFA
с насыщенной 16-углеродной прямой цепью (H16:0) проявляли наиболее выраженный канцеростатический эффект (при
37 ° уровень жизнеспосоности составил 60,0%; при 42 ° 49,6% (WST-1)) по сравнению с таковым насыщенных и ненасыщенных
HFAs, содержащих 12, 15 или 16 атомов углерода. анцеростатическая активность значительно возрастала при
этилэтерификации насыщенных жирных кислот, таких как H16:0 (при 37 ° 42,3%; при 42 ° 11,2%, ibid) и H15:0
(при 37 ° 74,6%; при 42 ° 25,3% , ibid), в то время как производные ненасыщенных кислот были высокоэффективны
только в комбинации с гипертермией. Увеличение периода инкубации клеток до 72 ч при той же концентрации веществ
приводило к значительному увеличению их канцеростатического действия (этиловый эфир H16:0 1,3%; этиловый эфир
H15:0 ethylesther 8,0%), подтвержденного данными окраски трипановым синим. рименение гипертермии также усиливало
канцеростатическое действие соединений (1,2%; 2,1%, ibid). Результаты исследования методом SEM показали, что
клетки EAT, инкубированные с этиловым эфиром H16:0, разруаются с нарушением клеточной структуры и исчезновением
микроволокон. Выводы: в комбинации с гипертермией этиловый эфир H16:0 про ет высокую канцеростатическую
активность in vitro, что говорит о возможности применения соединения в терапии опухолевых заболеваний
Neutral B Flavor Tagging for the Measurement of Mixing-induced CP Violation at Belle
We describe a flavor tagging algorithm used in measurements of the CP
violation parameter sin2phi_1 at the Belle experiment. Efficiencies and wrong
tag fractions are evaluated using flavor-specific B meson decays into hadronic
and semileptonic modes. We achieve a total effective efficiency of $ 28.8 +-
0.6 %.Comment: 28 pages, 9 figure
Data production models for the CDF experiment
The data production for the CDF experiment is conducted on a large Linux PC
farm designed to meet the needs of data collection at a maximum rate of 40
MByte/sec. We present two data production models that exploits advances in
computing and communication technology. The first production farm is a
centralized system that has achieved a stable data processing rate of
approximately 2 TByte per day. The recently upgraded farm is migrated to the
SAM (Sequential Access to data via Metadata) data handling system. The software
and hardware of the CDF production farms has been successful in providing large
computing and data throughput capacity to the experiment.Comment: 8 pages, 9 figures; presented at HPC Asia2005, Beijing, China, Nov 30
- Dec 3, 200
Data processing model for the CDF experiment
The data processing model for the CDF experiment is described. Data
processing reconstructs events from parallel data streams taken with different
combinations of physics event triggers and further splits the events into
datasets of specialized physics datasets. The design of the processing control
system faces strict requirements on bookkeeping records, which trace the status
of data files and event contents during processing and storage. The computing
architecture was updated to meet the mass data flow of the Run II data
collection, recently upgraded to a maximum rate of 40 MByte/sec. The data
processing facility consists of a large cluster of Linux computers with data
movement managed by the CDF data handling system to a multi-petaByte Enstore
tape library. The latest processing cycle has achieved a stable speed of 35
MByte/sec (3 TByte/day). It can be readily scaled by increasing CPU and
data-handling capacity as required.Comment: 12 pages, 10 figures, submitted to IEEE-TN
Membolic Imaging of Glycoconjugate Synthesis in Tumors with PET Using 6-[18F]Fluoro-L-Fucose
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