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K L Lu

Publications and source records attributed to K L Lu.

7 recordsLinked to original sources
PubMed2001

Assembly of a robust, thermally stable porous cobalt(II) nicotinate framework based on a dicobalt carboxylate unit.

A series of robust, thermally stable open-framework cobalt nicotinate compounds, Co(2)(H(2)O)[C(6)H(4)O(2)N](4).0.5CH(3)CH(2)OH.0.5H(2)O (1), Co(2)(H(2)O)[C(6)H(4)O(2)N](4) (2), and Co(2)(H(2)O)[C(6)H(4)O(2)N](4).C(6)H(5)CH(2)OH (3), based on rigid dimetallic carboxylate clusters as the basic building unit have been prepared. Single-crystal X-ray crystallographic analyses of 1 and 3 reveal the host framework possessing an effective channel area with the dimensions of 10.8 x 4.5 A. These channels can accommodate guest molecules of various sizes and shapes such as ethanol, water, and benzyl alcohol. Thermogravimetric analysis shows a two-step weight loss corresponding to the loss of guest molecules followed by the loss of coordinated water. The host framework is thermally stable up to 295 degrees C. The cobalt nicotinate host remains intact, even upon the removal of the guest to form compound 2 as revealed by single-crystal X-ray diffraction analysis. Crystal data for 1: Co(2)(H(2)O)[C(6)H(4)O(2)N)](4).0.5CH(3)CH(2)OH.0.5H(2)O, fw = 656.33, triclinic, space group P(-)1, a = 10.5407(2) A, b = 11.8266(3) A, c = 14.1122(2) A, alpha = 106.878(4) degrees, beta = 102.411(2) degrees, gamma = 111.011(3) degrees, V = 1467.9(5) A(3), Z = 2. Crystal data for 2: Co(2)(H(2)O)[C(6)H(4)O(2)N](4), fw = 624.28, triclinic, space group P(-)1, a = 10.507(3) A, b = 11.824(2) A, c = 14.113(3) A, alpha = 107.06(2) degrees, beta = 102.39(2) degrees, gamma = 111.105(16) degrees, V = 1459.5(6) A(3), Z = 2. Crystal data for 3: Co(2)(H(2)O)[C(6)H(4)O(2)N](4).C(6)H(5)CH(2)OH, fw = 732.42, triclinic, space group P(-)1, a = 10.6671(6) A, b = 12.0063(7) A, c = 14.0658(8) A, alpha = 106.7180(10) degrees, beta = 102.2790(10) degrees, gamma = 111.1900(10) degrees, V = 1504.1(6) A(3), Z = 2. The magnetic exchange coupling between the dicobalt centers for compounds 1 and 3 are analyzed on the basis of both the Curie-Weiss expression and a binuclear magnetic model. The negative values of the magnetic exchange coupling constant indicate the antiferromagnetic nature within the cobalt dimer.

Journal Article↗
PubMed2001

Analysis of three lupane type triterpenoids in Helicteres angustifolia by high-performance liquid chromatography.

Kang-chih-ma is the dried roots and stems of Helicteres angustifolia (Sterculiaceae) and a commonly used folk herbal drug in Taiwan. It possesses antidotal, analgesic, anti-inflammatory and anti-bacterial effects and is also known as a kind of tumor inhibitory plant. To evaluate the quality of H. angustifolia, a simple, rapid and accurate high-performance liquid chromatographic (HPLC) method was developed for the assay of three lupane type triterpenes: 3beta-acetoxy-27-benzoyloxylup-20(29)-en-28-oic acid methyl ester (methyl helicterate), 3beta-acetoxy-27-benzoyloxylup-20(29)-en-28-oic acid, and 3beta-acetoxy-27-(p-hydroxyl) benzoyloxylup-20(29)-en-28-oic acid methyl ester. The present HPLC system used an Inertsil ODS-2 column by gradient elution with acetonitrile and water as the mobile phase and detected at UV 230 nm. Regression equations revealed good linear relationships (correlation coefficients: 0.9922-0.9997). The relative standard deviations of these three constituents ranged between 1.05-3.14% (intraday) and 2.12-4.38% (interday). The contents of these three constituents of the heartwood and the bark of the roots of H. angustifolia in five different samples have also been determined.

Chromatography, High Pressure Liquid↗
PubMed2001

Bacteriologic and clinical efficacy of ofloxacin 0.3% versus ciprofloxacin 0.3% ophthalmic solutions in the treatment of patients with culture-positive bacterial keratitis.

PURPOSE: To compare the efficacy and safety of ofloxacin 0.3% ophthalmic solution with ciprofloxacin 0.3% ophthalmic solution in patients with culture-positive bacterial keratitis. METHODS: Patients with a microbiologic diagnosis of bacterial keratitis were included in this double-masked, parallel-group study and were randomized to treatment with either ofloxacin 0.3% or ciprofloxacin 0.3% ophthalmic solution. One drop of the study medication was instilled during the daytime according to the following schedule: every half-hour on study day 1, every hour on days 2 through 4, and every 2 hours on days 5 through 21. Healing, the primary outcome measure, was defined as complete reepithelialization, accompanied by nonprogression of stromal infiltrate for 2 days. Secondary outcome measures included signs and symptoms of infection. Patients were monitored throughout the study period for any adverse events. RESULTS: A total of 217 patients completed the study: 112 were treated with ofloxacin and 105 were treated with ciprofloxacin. Streptococcus pneumoniae was the most commonly encountered pathogen in all patients. Complete corneal reepithelialization occurred in 85% of those treated with ofloxacin and in 77% of those treated with ciprofloxacin (p = 0.32). The average time to corneal ulcer healing was 13.7 days in those treated with ofloxacin and 14.4 days in those treated with ciprofloxacin. Both treatments were well tolerated with no patient discontinuing the study because of side effects. CONCLUSION: Ofloxacin 0.3% and ciprofloxacin 0.3% ophthalmic solutions are effective and safe in the treatment of patients with culture-positive bacterial keratitis.

Adult↗
PubMed2000

The evaluation of the therapeutic effect of tao-shang-tsao on alpha-naphthylisothiocyanate and carbon tetrachloride-induced acute liver damage in rats.

The hepatoprotective effects of Tao-shang-tsao, Ixeris laevigata Sch.-Bip. var. oldhami Kitam., were studied on cholestatic hepatitis induced by alpha-naphthylisothiocyanate (ANIT, 100 mg/10 ml/kg, in olive oil, i.p.) and acute hepatitis induced by carbon tetrachloride (20% CCl4/olive oil, 1.5 ml/kg, i.p.) in rats by post-treatment with the crude methanolic extracts of I. laevigata (0.3, 1.0, and 2.0 g/kg) orally in the therapeutic model. Hepatoprotective activity was monitored by estimating the serum transaminases concentrations and histopathological changes in the livers of experimental rats. It was found that the I. laevigata extract significantly decreased the acute elevation of serum transaminases by biochemical examination. According to pathohistological studies in the liver of experimental rats, the crude I. laevigata extract ameliorates the central necrosis, fatty change or proliferation of bile duct epithelium focal necrosis caused by ANIT or CCl4-induced hepatitis rats.

1-Naphthylisothiocyanate↗
PubMed1996

Comparison of in vitro antiproliferative effects of steroids and nonsteroidal antiinflammatory drugs on human keratocytes.

Corticosteroids are currently administered after photorefractive keratectomy (PRK) to reduce corneal haze and myopic regression, However the beneficial effects of corticosteroids are controversial, and they are associated with many side effects. In this study we compared the in vitro antiproliferative effects of nonsteroidal antiinflammatory drugs (NSAIDs), diclofenac and flurbiprofen, with those of dexamethasone on human keratocytes. Human keratocytes were incubated with various concentrations of diclofenac, flurbiprofen, and dexamethasone. The control samples were incubated under the same conditions except for the absence of drugs. Proliferation of the keratocytes was measured by [3H]thymidine uptake into DNA on days 1, 2, and 4. Diclofenac was the most potent agent, inducing dose-dependent inhibition at concentrations > or = 10(-1) mM on days 1 and 2 and > or = 10(-5) mm on day 4. Flurbiprofen followed closely, inhibiting keratocytes at and above 1 mm on day 1, 10(-1) mm on day 2, and 10(-4) mm on day 4. Dexamethasone was the least effective, exhibiting inhibition at and above 25 mM on day 1, 5 mM on day 2, and 1 mM on day 4 (Wilcoxon rank sum test, P < or = 0.05). The ID50S reflect the same trend (day 4: diclofenac = 0.03 mM, flurbiprofen = 0.2 mM, dexamethasone = 3.2 mM). In addition, diclofenac and dexamethasone showed time-dependent antiproliferative effects. These results indicate that NSAIDs are more potent than corticosteroids in inhibiting proliferation of human keratocytes in vitro, and suggesting a potential use of NSAIDs in modulating corneal wound healing after PRK.

Anti-Inflammatory Agents↗
PubMed1993

Secondary metabolites resulting from degradation of PR toxin by Penicillium roqueforti.

PR toxin is a secondary metabolite of the fungus Penicillium roqueforti. It is lethal to rats, mice, and cats. Usually, the amount of PR toxin in the culture medium decreases from its maximum on day 15 to zero within 3 to 4 days. We found that two were secondary metabolites produced in the culture medium of this fungus while the production of PR toxin was decreasing. We isolated and purified the two compounds in pure and colorless crystalline form. On the basis of elemental analysis and mass, 1H and 13C nuclear magnetic resonance, infrared, and UV spectroscopies, the two compounds were identified as PR-imine (C17H21O5N) and PR-amide (C17H21O6N). The structures of both compounds and of PR toxin (C17H20O6) were closely related, and the peak production of PR toxin appeared earlier than those of PR-imine and PR-amide. Moreover, PR toxin was transformed to PR-imine when PR toxin was incubated with the culture medium on a given culture day. Thus, we propose that PR toxin is degraded into PR-imine and PR-amide in the culture medium of P. roqueforti.

Amides↗