• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.20 no.5
• /
• pp.237-242
• /
• 2010

Magnesium-substituted BCP (biphasic calcium phosphate) powders were prepared by incorporating small amounts of magnesium into the structure of different hydroxyapatite (HAp)/${\beta}$-tricalcium phosphate (${\beta}$-TCP) ratios through coprecipitation method. A series of magnesium substitutions ranging from 0, 0.5, and 1.0 wt%, which are comparable to the measured magnesium contents, were performed. The obtained powders were characterized by the following analytical techniques: X-ray diffraction analysis (XRD), Thermo Gravimetric Analyzer (TGA) and Fourier transform infrared spectroscopy (FT-IR). The results have shown that substitution of magnesium in the calcium-deficient apatites resulted in the formation of biphasic mixtures of different HAP/${\beta}$-TCP ratios after heating above $1000^{\circ}C$. The 1.0 wt% magnesiumsubstituted-BCP were soaked in Hank's solutions after 2 weeks to observe the morphology of the biocement, especially needle-like hydroxyapatite crystals and to estimate the length and diameter of nanoneedle crystals.

• Archives of Pharmacal Research
• /
• v.15 no.3
• /
• pp.246-250
• /
• 1992

Acetaminophen (AAP) and ranitidine (RT) were coadministered orally to nine rats, and the possible contribution of the gastric emptying to the plasma concentration profiles of them was examined. The drugs showed multiple plasma peaks similar to the respective ones after separated administration of each durg. IT Implies that there is no significant interaction between AAP and RT in terms of the gastric emptying or drug absorption. There were no significant linear correlations of the peak patterns (peak height and peak time) between AAP andd RT. It is contrary to the expectation from the biphasic gastric emptying (BGE) theory previously suggested for AAP and RT. The BGE theory. Therefore, seemed to have some draw-backs in explaining satisfactorily the multiple plasma peaks of AAP and RT. Two more doubts raised previously against the BGE theory were also discussed.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.10
• /
• pp.3203-3207
• /
• 2012

The nucleophilic substitution reactions of diisopropyl chlorothiophosphate (5) with X-pyridines have been kinetically studied in MeCN at $35.0^{\circ}C$. The Hammett and Br$\ddot{o}$nsted plots for the substituent X variations in the nucleophiles show biphasic concave upwards with a break point at X = 3-Ph. The pyridinolysis rate of 5 exhibits great negative deviation from the Taft plot. A concerted $S_N2$ mechanism is proposed involving a change of the attacking direction of the X-pyridines from a frontside attack with the strongly basic pyridines to a backside attack with the weakly basic pyridines.

• The Journal of Korean Medicine
• /
• v.39 no.3
• /
• pp.101-109
• /
• 2018

Objectives: To report the effect of Sajaehyangbu-hwan on a polycystic ovary syndrome(PCOS) patient with anovulation. Methods: The patient with PCOS was treated by Sajaehyangbu-hwan twice a day. The patient measured basal body temperature(BBT) and took a urine luteinizing hormone test(LH test) for three months to predict ovulation. Results: Two ovulations were observed in BBT and LH test results within three months and the typical biphasic BBT pattern was established. Conclusions: Sajaehyangbu-hwan has an effect on establishing obvious biphasic pattern in BBT of the patient with PCOS and the anovulation caused by PCOS.

• Journal of Korean Neurosurgical Society
• /
• v.42 no.1
• /
• pp.67-70
• /
• 2007

Synovial sarcomas are rare soft tissue malignancies arising from tendons, tendon sheaths, and bursal structures. These tumors usually develop in the extremities of adolescents and young adults. Uncommonly, these tumors may arise in the head and neck approximately 9% of all synovial sarcomas. Most common sites of head and neck synovial sarcomas are hypopharynx and surrounding structures of paranasal sinuses. However, frontal bone without involving paranasal sinus is extremely rare. We report a case of biphasic synovial sarcoma of the frontal bone discuss the clinical and pathologic features of this case with the literature review.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.12
• /
• pp.4179-4184
• /
• 2011

The nucleophilic substitution reactions of bis(2,6-dimethylphenyl) chlorophosphate (5), containing the four ortho-methyl substituents, with X-pyridines are investigated kinetically in MeCN at $65.0^{\circ}C$. The free energy correlations for substituent X variations in the nucleophiles exhibit biphasic concave upwards with a breakpoint at a X = 3-Cl. Unusual positive ${\rho}_X$ (= +5.40) and negative ${\beta}_X$ (= -0.83) values are obtained with the weakly basic pyridines. The pyridinolysis rate of 5 is hundreds times slower compared to that of bis(phenyl) chlorophosphate because of the steric hindrance of the four ortho-methyl substituents in the two phenyl rings. Ion-pair mechanism is proposed and positive ${\rho}_X$ and negative ${\beta}_X$ values are substantiated by an imbalance of the transition state.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.12
• /
• pp.4387-4391
• /
• 2011

The kinetic studies on the pyridinolysis of diisopropyl thiophosphinic chloride have been carried out in acetonitrile at $55.0^{\circ}C$. The free energy correlations for substituent X variations in the X-pyridines are biphasic concave upwards with a break point at X = 3-Ph. A concerted SN2 mechanism is proposed with a change of the attacking direction of the X-pyridine from a frontside attack for the strongly basic pyridines to a backside attack for the weakly basic pyridines. The factors to determine the rates and thio effects on the rates for the pyridinolyses of thiophophinic chloride, chlorothiophosphate, phosphinic chloride, phosphonochloridothioate, and chlorophosphate systems are briefly reviewed on the basis of the magnitude of the positive charge of the reaction center P atom and steric effects of the two ligands.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.11
• /
• pp.3372-3376
• /
• 2013

The kinetic studies on the reactions of ethyl methyl (2) and ethyl propyl (4) chlorothiophosphates with X-pyridines have been carried out in acetonitrile at $35.0^{\circ}C$. The free energy correlations with X show biphasic concave upwards with a break point at X = H (2) and 3-Ph (4), respectively. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed based on the magnitudes of selectivity parameters for both substrates. The considerably large values of ${\beta}_X$ = 1.50(2) and 1.44(4) with strongly basic pyridines and relatively small values of ${\beta}_X$ = 0.43(2) and 0.36(4) with weakly basic pyridines are interpreted as a change of the attacking direction of the X-pyridines from a frontside to a backside attack toward the chloride leaving group.

• Journal of Pharmaceutical Investigation
• /
• v.21 no.4
• /
• pp.201-213
• /
• 1991

There are many drugs reproted to show unusual pharmacokinetic behavior by producing a significant secondary peak in the plasma concentration-time curve after oral administration. The drugs are ranitidine, cimetidine, acetaminophen, aspirin, furosemide, bumetanide, piretanide, veralipride, sobrerol, penicillamine and doxycycline etc. Enterohepatic circulation-, two absorption site-, biphasic gastric emptying-, tissue deposition- and multi-fraction absorption theories have been suggested for the mechanisms of this phenomenon. Here, the theories were reviewed and critisized for their validity as a possible mechanism of the multiple peak phenomenon.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.3
• /
• pp.1085-1088
• /
• 2012