Tyrosinase inhibitors and insecticidal materials produced by Burkholderia cepacia using squid pen as the sole carbon and nitrogen source

[[abstract]]Reports of tyrosinase inhibitors from microorganisms are rare. A tyrosinase inhibitor- and insecticidal materials-producing bacterium, strain TKU026, was isolated from Taiwanese soil and identified as Burkholderia cepacia. Among the tested chitin-containing materials, squid pen best enhanced the production of tyrosinase inhibitors and insecticidal materials. The tyrosinase inhibitory activity (5000 U/mL) and insecticidal activity (81%) against Drosophila larvae was maximised after cultivation on 1% squid-pen containing medium for three days. The tyrosinase inhibitory activity persisted even when the culture was treated with acidic or alkaline conditions of pH 3 or 11. The activities of both tyrosinase inhibitors and insecticide remained at 100%, even after treatment at 100℃ for 30 min. The culture supernatant after three days of cultivation also showed antifungal activity against Aspergillus fumigatus and Fusarium oxysporum with maximal activities of 100% and 80%, respectively, but no antibacterial activity against Escherichia coli was observed. The tyrosinase inhibitors were assumed to be polyphenolic compounds according to the results of chromatography.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子版[[countrycodes]]NL

Bioaccumulation and ecotoxicity of carbon nanotubes

Carbon nanotubes (CNT) have numerous industrial applications and may be released to the environment. In the aquatic environment, pristine or functionalized CNT have different dispersion behavior, potentially leading to different risks of exposure along the water column. Data included in this review indicate that CNT do not cross biological barriers readily. When internalized, only a minimal fraction of CNT translocate into organism body compartments. The reported CNT toxicity depends on exposure conditions, model organism, CNT-type, dispersion state and concentration. In the ecotoxicological tests, the aquatic organisms were generally found to be more sensitive than terrestrial organisms. Invertebrates were more sensitive than vertebrates. Single-walled CNT were found to be more toxic than double-/multi-walled CNT. Generally, the effect concentrations documented in literature were above current modeled average environmental concentrations. Measurement data are needed for estimation of environmental no-effect concentrations. Future studies with benchmark materials are needed to generate comparable results. Studies have to include better characterization of the starting materials, of the dispersions and of the biological fate, to obtain better knowledge of the exposure/effect relationships

Assessing Factors Affecting M&As Versus Greenfield FDI in Emerging Countries

A host of external (global and regional) and internal (country-specific) factors affect Multinational Enterprises' Foreign Direct Investment (FDI) decisions. Differentiating the two entry modes of FDI (mergers and acquisitions [M&A] and Greenfield investment), this paper aims to empirically assess whether or not being a part of global emerging market economies or any specific emerging regions affects investors' decisions of FDI flows to an emerging country in addition to various country-specific factors. For this purpose, this paper employs a system generalized method of moments estimator for the panel data consisting of 40 emerging countries for the period 1990–2009. The results suggest that there exist a strong and significant global and regional influence in both types of FDI flows to an emerging country. M&A appears to be more sensitive to external factors, both global and regional effects are about twice stronger for M&A than for Greenfield FDI. The results also suggest that country- specific factors matter a lot for FDI flows both in the form of M&A and Greenfield FDI, pointing to the importance of government roles in helping stabilize FDI flows to emerging countries. This paper also offers empirical evidence which is consistent with the phenomenon of a fire-sale FDI during the period of financial crisis. Additional evidence using extensive and intensive margins of M&A sales suggest that the fire-sale does not necessarily imply an increase in the number of deals, but it may reflect the sales of big firms during the crisis

Fiberoptic bronchoscopy for the rapid diagnosis of smear-negative pulmonary tuberculosis

<p>Abstract</p> <p>Background</p> <p>This study was aimed to investigate the diagnostic value of fiberoptic bronchoscopy (FOB) with chest high-resolution computed tomography (HRCT) for the rapid diagnosis of active pulmonary tuberculosis (PTB) in patients suspected of PTB but found to have a negative sputum acid-fast bacilli (AFB) smear.</p> <p>Methods</p> <p>We evaluated the diagnostic accuracy of results from FOB and HRCT in 126 patients at Gangnam Severance Hospital (Seoul, Korea) who were suspected of having PTB.</p> <p>Results</p> <p>Of 126 patients who had negative sputum AFB smears but were suspected of having PTB, 54 patients were confirmed as having active PTB. Hemoptysis was negatively correlated with active PTB. Tree-in-bud appearance on HRCT was significantly associated with active PTB. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FOB alone was 75.9%, 97.2%, 95.3%, and 84.3%, respectively, for the rapid diagnosis of active PTB. The combination of FOB and HRCT improved the sensitivity to 96.3% and the NPV to 96.2%.</p> <p>Conclusions</p> <p>FOB is a useful tool in the rapid diagnosis of active PTB with a high sensitivity, specificity, PPV and NPV in sputum smear-negative PTB-suspected patients. HRCT improves the sensitivity of FOB when used in combination with FOB in sputum smear-negative patients suspected of having PTB.</p