Remarkable solvent, porphyrin ligand, and substrate effects on participation of multiple active oxidants in manganese(III) porphyrin catalyzed oxidation reactions.

The participation of multiple active oxidants generated from the reactions of two manganese(III) porphyrin complexes containing electron-withdrawing and -donating substituents with peroxyphenylacetic acid (PPAA) as a mechanistic probe was studied by carrying out catalytic oxidations of cyclohexene, 1-octene, and ethylbenzene in various solvent systems, namely, toluene, CH(2) Cl(2) , CH(3) CN, and H(2) O/CH(3) CN (1:4). With an increase in the concentration of the easy-to-oxidize substrate cyclohexene in the presence of [(TMP)MnCl] (1a) with electron-donating substituents, the ratio of heterolysis to homolysis increased gradually in all solvent systems, suggesting that [(TMP)Mn-OOC(O)R] species 2a is the major active species. When the substrate was changed from the easy-to-oxidize one (cyclohexene) to difficult-to-oxidize ones (1-octene and ethylbenzene), the ratio of heterolysis to homolysis increased a little or did not change. [(F(20) TPP)Mn-OOC(O)R] species 2b generated from the reaction of [(F(20) TPP)MnCl] (1b) with electron-withdrawing substituents and PPAA also gradually becomes involved in olefin epoxidation (although to a much lesser degree than with [(TMP)Mn-OOR] 2a) depending on the concentration of the easy-to-oxidize substrate cyclohexene in all aprotic solvent systems except for CH(3) CN, whereas Mn(V)=O species is the major active oxidant in the protic solvent system. With difficult-to-oxidize substrates, the ratio of heterolysis to homolysis did not vary except for 1-octene in toluene, indicating that a Mn(V)=O intermediate generated from the heterolytic cleavage of 2b becomes a major reactive species. We also studied the competitive epoxidations of cis-2-octene and trans-2-octene with two manganese(III) porphyrin complexes by meta-chloroperbenzoic acid (MCPBA) in various solvents under catalytic reaction conditions. The ratios of cis- to trans-2-octene oxide formed in the reactions of MCPBA varied depending on the substrate concentration, further supporting the contention that the reactions of manganese porphyrin complexes with peracids generate multiple reactive oxidizing intermediates.

Terminal and internal olefin epoxidation with cobalt(II) as the catalyst: evidence for an active oxidant Co(II)-acylperoxo species.

A simple catalytic system that uses commercially available cobalt(II) perchlorate as the catalyst and 3-chloroperoxybenzoic acid as the oxidant was found to be very effective in the epoxidation of a variety of olefins with high product selectivity under mild experimental conditions. More challenging targets such as terminal aliphatic olefins were also efficiently and selectively oxidized to the corresponding epoxides. This catalytic system features a nearly nonradical-type and highly stereospecific epoxidation of aliphatic olefin, fast conversion, and high yields. Olefin epoxidation by this catalytic system is proposed to involve a new reactive Co(II)-OOC(O)R species, based on evidence from H(2)(18)O-exchange experiments, the use of peroxyphenylacetic acid as a mechanistic probe, reactivity and Hammett studies, EPR, and ESI-mass spectrometric investigation. However, the O-O bond of a Co(II)-acylperoxo intermediate (Co(II)-OOC(O)R) was found to be cleaved both heterolytically and homolytically if there is no substrate.

Bis(µ-3-carb-oxy-2-hy-droxy-propane-1,2-dicarboxyl-ato)bis(diaquazinc)-1,2-bis-(pyridin-4-yl)ethene-water (1/1/2).

The asymmetric unit of the title compound, [Zn(2)(C(6)H(6)O(7))(2)(H(2)O)(4)]·C(12)H(10)N(2)·2H(2)O, comprises half of a centrosymmetric complex dimer, half of a 1,2-bis-(pyridin-4-yl)ethene mol-ecule, which lies across an inversion centre, and one lattice water mol-ecule. Carboxyl-ate groups of two dianionic citrate ligands bridge two Zn(II) ions to give the cyclic dimer, with each Zn(II) ion coordinated by four O atoms from the chelating citrate ligand (one hy-droxy and three carboxyl-ate, with one bridging) and two water O atoms, forming a distorted octa-hedral environment [Zn-O = 2.040 (3)-2.244 (3) Å]. In the crystal, O-H⋯O and O-H⋯N hydrogen bonds involving hy-droxy groups and both coordinating and lattice water mol-ecules link the dimers to give a three-dimensional framework structure.

Bis(µ-2-carboxymethyl-2-hydroxy-butane-dioato)bis-[diaqua-manganese(II)]-1,2-bis-(pyridin-4-yl)ethane-water (1/1/2).

The asymmetric unit of the title compound, [Mn(2)(C(6)H(6)O(7))(2)(H(2)O)(4)]·C(12)H(12)N(2)·2H(2)O, comprises half of a centrosymmetric dimer, half of a 1,2-bis-(pyridin-4-yl)ethane and one water mol-ecule. Two citrate ligands bridge two Mn(II) ions, the Mn(II) ion being coordinated by four O atoms from the citrate(2-) ligands and two water O atoms, forming a distorted octa-hedral environment. In the crystal, O-H⋯O hydrogen bonds link the centrosymmetric dimers and lattice water mol-ecules into a three-dimensional structure which is further stabilized by inter-molecular π-π inter-actions [centroid-centroid distance = 3.792 (2) Å].

Bis(µ-2-carb-oxy-methyl-2-hy-droxy-butane-dioato)bis-[diaqua-manganese(II)]-1,2-bis-(pyridin-4-yl)ethene-water (1/1/2).

The asymmetric unit of the title compound, [Mn2(C6H6O7)2(H2O)4]·C12H10N2·2H2O, contains half of the centrosymmetric Mn complex dimer, half of a 1,2-bis-(pyridin-4-yl)ethene mol-ecule, which lies across an inversion center, and one water mol-ecule. Two citrate ligands bridge two Mn(II) ions, and each Mn(II) atom is coordinated by four O atoms from the citrate ligands (one from hy-droxy and three from carboxyl-ate groups) and two water O atoms, forming a distorted octa-hedral environment. In the crystal, O-H⋯O and O-H⋯N hydrogen bonds link the centrosymmetric dimers and lattice water mol-ecules into a three-dimensional structure which is further stabilized by inter-molecular π-π inter-actions [centroid-centroid distance = 3.959 (2) Å]. Weak C-H⋯O hydrogen bonding interactions are also observed.

The effect of exercise on prevention of the common cold: a meta-analysis of randomized controlled trial studies.

BACKGROUND: Because there is no specific treatment for the common cold, many previous studies have focused on prevention of the common cold. There were some studies reporting that regular, moderate-intensity exercise increases immunity and prevents the common cold. We conducted a meta-analysis to determine the effects of exercise on prevention of the common cold. METHODS: We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL for studies released through June 2013. We manually searched the references. Two authors independently extracted the data. To assess the risk of bias of included literature, Cochrane Collaboration's tool for assessing risk of bias was used. Review Manager ver. 5.2 (RevMan, Cochrane Collaboration) was used for statistical analysis. RESULTS: Four randomized controlled trials were identified. A total of 281 participants, 134 in the exercise group and 147 in the control group, were included. The effect of exercise on the prevention of the common cold had a relative risk (RR) of 0.73 (95% confidence interval [CI], 0.56 to 0.95; I(2) = 7%). The mean difference of mean illness days between exercise group and control group was -3.50 (95% CI, -6.06 to -0.94; I(2) = 93%). In the subgroup analysis, the RR of under 16 weeks exercise was 0.79 (95% CI, 0.58 to 1.08). CONCLUSION: In this meta-analysis, regular, moderate-intensity exercise may have an effect on the prevention of the common cold. But numbers of included studies and participants were too small and quality of included studies was relatively poor. Subsequent well-designed studies with larger sample size are needed to clarify the association.

DNA cleavage induced by [Cu(L)x(NO3)2] (L=2,2'-dipyridylamine, 2,2'-bipyridine, dipicolylamine, x=1 or 2): Effect of the ligand structure.

The efficiency of [Cu(2,2'-bipyridine)2(NO3)]NO3, [Cu(2,2'-dipyridylamine)2(NO3)2], and [Cu(dipicolylamine)2(NO3)2] complexes (complex 1, 2 and 3, respectively) in oxidative DNA cleavage was examined by electrophoresis and linear dichroism (LD). Among the three Cu complexes, complex 1 showed the highest efficiency in super-coiled DNA (scDNA) cleavage in electrophoresis. The presence of tiron, a superoxide radical scavenger, suppressed the reaction almost completely. The LD signal at 260 nm decreased gradually as the time passed. The decrease in LD magnitude was explained best by the sum of the two single exponential curves. This suggests that the cleavage reaction involves two first order kinetic processes; an increase in flexibility due to scission of one of the strands and a shortening in the DNA stem due to cut of both strands of double stranded DNA (dsDNA). In agreement with the electrophoresis data, complex 1 exhibited the highest efficiency with the superoxide radical found to be the essential reactive oxygen species. The order of efficiency in both scDNA and dsDNA was as follows: complex 1>complex 2>complex 3. The electrochemical properties alone were insufficient to explain the observed efficiencies, even though reduction of the central Cu ion is essential for the oxidative DNA cleavage. This highlights the importance of an ability to ligate the molecular oxygen (or hydrogen peroxide) to the central Cu ion to produce the superoxide radical, in addition to the reduction of Cu ion, in oxidative DNA cleavage.

Hepatitis B surface antigen positivity after twinrix vaccination: a case report.

Travelers might have an increased risk of hepatitis B virus (HBV) infection. We report a case of prolonged transient hepatitis B surface antigenemia in a healthy Canadian female 8 days after administration of a combined hepatitis A and hepatitis B vaccine. Travel health providers providing hepatitis B vaccines need to be aware of this phenomenon and educate their patients accordingly.

The effect of probiotics on prevention of common cold: a meta-analysis of randomized controlled trial studies.

BACKGROUND: Probiotics are currently under focus for their immune improvement function. Many studies have been performed to assess the potential efficacy of probiotics in allergic disease, viral disease, respiratory disease, as well as gastrointestinal disease. This study performed a systematic review to determine the effects of probiotics on the prevention of the common cold. METHODS: We searched MEDLINE (PubMed), EMBASE, CINAHL, and Cochrane CENTRAL for studies released through June 2011. Two authors independently extracted the data. To assess the risk of bias of included literatures, Cochrane Collaboration's risk of bias tool was used. RESULTS: We identified 10 studies in 7 articles. A total 2,894 participants, 1,588 in the probiotics group and 1,306 in the control group, were included. The effect of probiotics on the prevention of the common cold had a relative risk (RR) of 0.92 (95% CI, 0.85 to 1.00, I(2) = 26%). In the subgroup analysis, the RR of administration of probiotics for 3 months or less was 0.82 (95% CI, 0.70 to 0.97). The RR of administration of probiotics over 3 months was 1.00 (95% CI, 0.92 to 1.09). The RR of administration of probiotics without any active intervention (vitamin and mineral) was 0.87 (95% CI, 0.78 to 0.97). CONCLUSION: In this meta-analysis, there was marginal effect of probiotics on the prevention of the common cold. The results implied that probiotics had a modest effect in common cold reduction. The balance of benefit and harms needs to be considered when using probiotics for common cold prevention.

A Comparison of the Efficacy and Safety of Non-Steroidal Anti-Inflammatory Drugs versus Acetaminophen in Symptom Relief for the Common Cold: A Meta-Analysis of Randomized Controlled Trial Studies.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen are widely used for common cold symptom relief. The objective of this study was to evaluate and compare the efficacy and safety of acetaminophen and NSAIDs in common cold symptom relief using meta-analysis of randomized controlled trial. METHODS: We searched MEDLINE (PubMed), Cochrane, EMBASE, CINAHL, KMbase, KoreaMed, National Assembly Library, and Riss4u for studies released through June 2012. Two authors independently extracted the data. To assess the risk of bias, the Cochrane Collaborations risk of bias tool was used. The Review Manager ver. 5.1 (RevMan) was used for statistics. RESULTS: We identified 5 studies. The relative benefit for participants with pain relief was 1.00 (95% confidence interval [CI], 0.96 to 1.05) and I(2) = 0%. The existence of the heterogeneity between studies was not important in this study, thus subgroup analysis was not implemented. The relative benefit for participants with rhinorrhea was 1.02 (95% CI, 0.77 to 1.35) and I(2) = 0%, which also indicates the existence of heterogeneity was not important. The relative risk of adverse events was 1.14 (95% CI, 0.93 to 1.40), I(2) = 0%. There was no apparent asymmetry in the funnel plot. CONCLUSION: There was no difference between NSAIDs and acetaminophen in common cold symptom relief.

CO2 selective dynamic two-dimensional Zn(II) coordination polymer.

A CO2 selective dynamic two-dimensional (2D) MOF system, [Zn(glu)(µ-bpe)]·2H2O (·2H2O) (glu = glutarate, bpe = 1,2-bis(4-pyridyl)ethylene), is prepared. Based on variable temperature PXRD patterns, I·2H2O exhibits a structural transformation of the framework upon desolvation. Various gas sorption analyses at low temperatures reveal that solvent-free I selectively adsorbs CO2 over N2, H2, and CH4. Stepped CO2 isotherms for solvent-free I with a large hysteresis between adsorption and desorption branches at 196 K indicate that I is a dynamic framework. Moreover, I·2H2O shows efficient heterogeneous catalytic reactivity for transesterification of various esters. The catalyst can be recycled multiple times without losing its original activity.

Zinc sensors with lower binding affinities for cellular imaging.

Zinc sensors based on 2,3-dipicolylamine (DPA) and quinoline have been synthesized. They fluoresced in the presence of Zn(2+) and remained fluorescent when other metal ions were present. Fluorescence enhancement of the sensors was not seen for most other metal ions. In vitro studies with fibroblasts showed fluorescence when sensor and Zn(2+) were present. As seen by single crystal X-ray analysis, four nitrogens from the sensor bind to Zn(2+). These new sensors have lower binding constants than the pentadentate sensors based on 2,2-DPA.

Real-time detection of DNA cleavage induced by [M(2,2'-bipyridine)2(NO3)](NO3) (M=Cu(II), Zn(II) and Cd(II)) complexes using linear dichroism technique.

The catalytic effect of [M(2,2'-bipyridine)2(NO3)](NO3) (M(bpy)2, M=Cu(II), Zn(II) and Cd(II)) on the super-coiled and double stranded DNA (scDNA and dsDNA) was examined by electrophoresis and a real-time detection linear dichroism (LD) technique. Although the Cu(bpy)2 complex effectively cleaved both types of DNA, the other two complexes were inactive. This was explained by the electrochemical properties of the metal complexes. The Cu(bpy)2 complex exhibited a redox potential at -0.222V with a peak to peak separation of 0.201V, whereas the other two metal complexes did not undergo any redox reaction. Both electrophoresis and LD measurements revealed the superoxide radical, ·O2(-), to be responsible for DNA cleavage. A kinetic study using the LD technique showed that the cleavage of dsDNA consisted of two first order reactions. The fast reaction is believed to reflect the cleavage of one strand, whereas the slow reaction involves the cleavage of the complementary strand at or near the first cleaved site.

A Comparison of Efficacy and Safety of Non-steroidal Anti-inflammatory Drugs versus Acetaminophen in the Treatment of Episodic Tension-type Headache: A Meta-analysis of Randomized Placebo-controlled Trial Studies.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen are widely used in the treatment of tension headache. The objective of this study was to evaluate and compare the efficacy and safety of single doses of acetaminophen and NSAIDs using meta-analysis of randomized placebo-controlled trial studies. METHODS: We searched MEDLINE, EMBASE, CINAHL, Cochrane, KMbase, KoreaMed, RiCH, National Assembly Library, Riss4u, and DBPIA for studies released through 27th July 2010. Two authors independently extracted the data. To assess the risk of bias, the Cochrane Collaborations risk of bias tool was used. Review Manager 5.0 was used for statistics. RESULTS: We identified 6 studies. The relative benefit of the NSAIDs group compared to the acetaminophen group for participants with at least 50% pain relief was 1.18 (95% confidence interval [CI], 0.99 to 1.39; I(2) = 85%). We did subgroup analysis based on allocation concealment versus non-allocation concealment, and low-dose NSAIDs versus high-dose NSAIDs. The relative benefit of the low-dose NSAIDs subgroup to the acetaminophen group was 0.98 (95% CI, 0.91 to 1.06; I(2) = 0%). However, the heterogeneity of other subgroup analysis was not settled. The relative risk for using rescue medication of the NSAIDs group compared to the acetaminophen group was 0.84 (95% CI, 0.64 to 1.12; I(2) = 47%). The relative risk for adverse events was 1.31(95% CI, 0.96 to 1.80; I(2) = 0%). CONCLUSION: In this meta-analysis, there was no difference between low-dose NSAIDs and acetaminophen in the efficacy of the treatment for tension type headache. The results suggested that high-dose NSAIDs have more effect but also have more adverse events. The balance of benefit and harm needs to be considered when using high-dose NSAIDs for tension headache.

The quality of reporting of cohort, case-control studies in the korean journal of family medicine.

BACKGROUND: The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement was developed to improve the reporting of observational studies. We aimed to evaluate the quality of reporting in cohort studies and case-control studies among observational studies published in the Korean Journal of Family Medicine. METHODS: We searched for cohort studies and case-control studies published as original articles in the Journal of the Korean Academy of Family Medicine during the period January 1992 through December 2009. The main outcome measures were the number and proportion of cohort studies and case-control studies that reported each of 22 checklist items of STROBE. RESULTS: We identified a total of 84 articles, of which 46 articles were cohort studies and 38 were case-control studies. Concerning methods, study designs (10%), bias (13%), study size (0%), statistical methods (12-c and 12-e items, 0%; 12-d item, cohort study, 6%) have been poorly reported. Of results, participants (5-6%), descriptive data (14-b item, 5%), and funding (1%) among other information have been poorly reported. CONCLUSION: The degree of adherence the STROBE recommendations was relatively low in cohort studies and case-control studies published in the Korean Journal of Family Medicine. An effort to improve the reporting of observational studies by application and recommendation of the STROBE statement is required.

Misinterpreting odds ratio in the articles published in korean journal of family medicine.

BACKGROUND: In reporting results of case-control studies, odds ratios are useful methods of reporting findings. However, odds ratios are often misinterpreted in the literature and by general readers. METHODS: We searched all original articles which were published in the Korean Journal of Family Medicine from 1980 to May 2011 and identified those that report "odds ratios." Misinterpretation of odds ratios as relative risks has been identified. Estimated risk ratios were calculated when possible and compared with odds ratios. RESULTS: One hundred and twenty-eight articles using odds ratios were identified. Among those, 122 articles were analyzed for the frequency of misinterpretation of odds ratios as relative risks. Twenty-two reports out of these 122 articles misinterpreted odds ratios as relative risks. The percentage of misinterpreting reports decreased over years. Seventy-seven reports were analyzed to compare the estimated risk ratios with odds ratios. In most of these articles, odds ratios were greater than estimated risk ratios, 60% of which had larger than 20% standardized differences. CONCLUSION: In reports published in the Korean Journal of Family Medicine, odds ratios are frequently used. They were misinterpreted in part of the reports, although decreasing trends over years were observed.

Effects of having usual source of care on preventive services and chronic disease control: a systematic review.

BACKGROUND: Having usual source of care has been associated with improved receipt of preventive services and control of chronic diseases (such as hypertension, diabetes, and hypercholesterolemia). The objective of this study was to examine whether having usual source of care is associated with improved receipt of preventive services and control of chronic diseases. METHODS: We searched MEDLINE, EMBASE, Cochrane, CINAHL, KMbase, KoreaMed, RiSS4U, National Assembly Library, and KISS for studies released through May 31st 2011. Two authors independently extracted the data. We manually searched the references and twenty recent related articles on PubMed. To assess the risk of bias RoBANS tool was used. RESULTS: We identified 10 studies. Most having usual source of care were associated with improved receipt of preventive services (cervical cancer screening, clinical breast exam, mammogram, prostate cancer screening, and flu shot) compared with no usual source of care. However, gastric cancer and colon cancer screening were difficult to conclude and blood pressure checkup showed mixed results. Overall there was no association between having usual source of care and smoking behaviors and the effect on chronic disease control was difficult to conclude. CONCLUSION: Having usual source of care was associated with improved receipt of preventive services and overall the results were consistent. So, the results suggested that having usual source of care may help to receive preventive services. Hereafter, cohort studies are needed to evaluate casual relationships and more studies are needed in various countries and systems.

Bifunctional 3D Cu-MOFs containing glutarates and bipyridyl ligands: selective CO2 sorption and heterogeneous catalysis.

We report bifunctional three-dimensional (3D) Cu-MOFs with high selectivity of CO(2) over N(2) and H(2) as well as high catalytic activity for transesterification of esters. The Cu-MOFs containing Cu(2) dinuclear units connected by glutarates and bipyridyl ligands are formulated as [{Cu(2)(Glu)(2)(µ-bpa)}·(CH(3)CN)](n) (1) and [{Cu(2)(Glu)(2)(µ-bpp)}·(C(3)H(6)O)](n) (2) (Glu = glutarate, bpa = 1,2-bis(4-pyridyl)ethane, bpp = 1,3-bis(4-pyridyl)propane). These two new bifunctional 3D Cu-MOFs possess very similar pore shape with different pore dimensions. Their gas sorption behaviors were investigated by using CO(2), N(2) and H(2) at suitable temperatures. Both MOFs exhibited good CO(2) selectivity over N(2) and H(2). MOF 1 having a smaller pore dimension exhibited much higher CO(2) adsorption enthalpy than MOF 2 having a larger pore dimension. However, MOF 2 exhibited more enhanced CO(2) uptake ability than MOF 1. A subtle variation of pore dimension indeed influenced the CO(2) uptake ability somewhat significantly especially at higher temperatures such as 273 K and 298 K. Heterogeneous catalytic activities of the MOFs were also investigated in detail. Only MOF 1 appeared to be an efficient, mild, and easily recyclable heterogeneous catalyst for the transesterification of esters and constitutes a promising class of heterogeneous catalysts that allowed reuse without a significant loss of activity through twenty runs with ester.

Correlation of CPX Scores with the Scores on Written Multiple-Choice Examinations on the Certifying Examination for Family Medicine in 2009 to 2011.

PURPOSE: Recently, the clinical practice examination (CPX) using standardized patients has been introduced into several specialty certifying examinations in Korea. The purpose of this paper was to determine the correlation of a resident's performance on the CPX with the comprehensive written multiple-choice question (MCQ) examination on the certifying examination for family medicine. METHODS: The subjects of this study were 1,023 residents who completed the 1st and 2nd certifying examination for family medicine between 2009 and 2011. We determined the correlation between the total scores and 4 domain scores (history taking, physical examination, patient education, and patient-physician interaction) on the CPX with the MCQ scores of the 1st written test and 2nd slide examination and the correlation between the total CPX score and scores on the CPX domains. RESULTS: The correlation between CPX score with each MCQ examination (0.21~0.45 with 1st written MCQ, 0.15~0.33 with 2nd slide MCQ) was lower than that between each MCQ examination (0.46~0.59). The CPX score on patient education did not correlate with the 1st written and 2nd MCQ scores. The CPX scores on history taking and physical examination correlated slightly with the 1st written MCQ scores. The global ratings of preceptor examiners had the highest correlation (r=0.68~0.82) with the total CPX scores. CONCLUSION: Considering the mild correlation of CPX scores with each MCQ examination, the CPX is more likely to measure other qualities, such as critical thinking and communication skills.