Plasmon-mediated photocatalytic conversion in Au or Ag nanorod aggregates by surface-enhanced Raman spectroscopy.

Plasmonic nanoparticles (NPs) hold considerable potential as photocatalysts owing to their robust light-matter interactions across diverse electromagnetic wavelengths, which significantly influence the photophysical characteristics of the adjacent molecular entities. Despite the widespread use of noble-metal NPs in surface-enhanced Raman scattering (SERS) applications, little is known about the kinetics of nanoparticle aggregation and how it affects their configurations. This study investigates the plasmon-driven photochemical conversion of 4-nitrobenzenethiol (NBT) to 4,4'-dimercaptoazobenzene (DMAB) on Au and Ag nanorods (NRs) through SERS. Significantly, photoconversion phenomena were observed on Ag NRs but not on Au NRs upon laser excitation at 633 nm. Finite-difference time-domain simulations revealed the presence of stronger electromagnetic fields on Ag NRs than on Au NRs. The aspect ratios and gaps between individual NPs in dimer configurations were determined to elucidate their effects on electromagnetic fields. The Ag NR dimer with an end-to-end configuration, an aspect ratio of 3.3, and a 1-nm gap exhibited the highest enhancement factor of 1.05 × 1012. Our results demonstrate that the primary contribution from diverse configurations in NR aggregates is the end-to-end configuration. The proposed NP design with adjustable parameters is expected to advance research in plasmonics, sensing, and wireless communications. These findings also contribute to the understanding of plasmon-driven photochemical processes in metallic nanostructures.

Tuberculosis-induced acute respiratory distress syndrome treated with veno-venous extracorporeal membrane oxygenation.

Tuberculosis (TB) is a rare but known cause of acute respiratory distress syndrome (ARDS) with a high mortality. Veno-venous extracorporeal membrane oxygenation (VV-ECMO) may be an alternative option for treating TB-induced ARDS. However, the literature on TB-induced ARDS treated with VV-ECMO is limited and the most of them were prolonged therapy. We report on a-48-year-old man with TB-induced ARDS who was successfully treated by short-term use of VV-ECMO (5 days). He was developed symptoms and hospitalized with severe dyspnea in a local hospital for 3 days before admission to our hospital. At the time when he was transferred to our hospital, his chest computed tomography showed bilateral, diffuse and consolidative shadows all over the lungs, the ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) was 50 mmHg, and respiratory system compliance was 12.5 mL/cmH2O. Two days after admission, Mycobacterium tuberculosis was detected by a sputum smear examination and he was diagnosed with TB-induced ARDS. VV-ECMO support was then initiated with administration of anti-TB drugs and systemic corticosteroid treatment. On the 4thday of ECMO support, his PaO2/FiO2 increased to 400 mmHg and lung compliance increased to 45 mL/cmH2O. He was weaned from ECMO on the 5th day of ECMO support and was extubated at the 8th day. He was discharged from hospital on the 47th hospitalized day and continued anti-TB medication at home. VV-ECMO is effective for TB-induced ARDS even in short-term administration if progression of ARDS is rapid.

Climate Variability and Dengue Hemorrhagic Fever in Ba Tri District, Ben Tre Province, Vietnam during 2004-2014.

BACKGROUND: Currently, dengue fever/dengue hemorrhagic fever (DF/DHF) is an important public health challenge in many areas, including the Ba Tri District, Ben Tre Province, Vietnam. METHODS AND AIM: This study was conducted in 2015 using a retrospective secondary data analysis on monthly data of DF/DHF cases and climate conditions from 2004-2014 in Ba Tri District, which aimed to explore the relationship between DF/DHF and climate variables. RESULTS: During the period of 2004-2014, there were 5728 reported DF/DHF cases and five deaths. The disease occurred year round, with peaked from May to October and the highest number of cases occurred in June and July. There were strong correlations between monthly DF/DHF cases within that period with average rainfall (r = 0.70), humidity (r = 0.59), mosquito density (r = 0.82), and Breteau index (r = 0.81). A moderate association was observed between the monthly average number of DF/DHF cases and the average temperature (r = 0.37). The monthly DF/DHF cases were also moderately correlated with the Aedes mosquito density. CONCLUSIONS AND RECOMMENDATIONS: Local health authorities need to monitor DF/DHF cases at the beginning of epidemic period, starting from April and to apply timely disease prevention measures to avoid the spreading of the disease in the following months. More vector control efforts should be implemented in March and April, just before the rainy season, which can help to reduce the vector density and the epidemic risk. A larger scale study using national data and for a longer period of time should be undertaken to thoroughly describe the correlation between climate variability and DF/DHF cases as well as for modeling and building projection model for the disease in the coming years. This can play an important role for active prevention of DF/DHF in Vietnam under the impacts of climate change and weather variability.

Development and validation of a liquid chromatography-mass spectrometry method for the simultaneous quantification of artesunate and dihydroartemisinin in human plasma.

The present study describes the development and validation of a simple, sensitive, and specific liquid chromatography-mass spectrometry (LC-MS) analytical method used for the co-quantification of artesunate (ARS) and its active metabolite, dihydroartemisinin (DHA), in human plasma, using artemisinin (ARN) as an internal standard. The liquid-liquid extraction of samples was carried out using dichloromethane and tert.-methyl butyl ether (at a ratio of 8:2 v/v) and then evaporated to dryness by a stream of nitrogen gas at room temperature. Chromatographic separation and mass analysis were performed on the Agilent 1100 Series Liquid Chromatography/Mass Spectrometer Detector Trap system, using electrospray ionization as an interface. The stationary phase was an Elipse XDB-C18 column. The mobile phase contained acetonitrile and 0.003 M glacial acetic acid at a ratio of 62:38 (v/v) delivered at a flow rate of 0.5 ml per minute. Positive ion mode was selected to detect extracted ions at m/z 407 and 261 for ARS, at m/z 307 and 261 for DHA, and at m/z 305 for ARN. The retention times for alpha-DHA, ARS, beta-DHA, and ARN were 6.6, 8.0, 9.2, and 10.8 minutes, respectively, and the total chromatography run time was 12 minutes. The limit of detection (LOD) was 2 ng/ml while the limit of quantification (LOQ) was 10 ng/ml for both ARS and DHA. In order to address any complications caused by the spontaneous non-catalytic breakdown of ARS to DHA, two calibration curves were prepared separately for both analytes. These graphs were found to be linear over the range of 10 to 3,200 ng/ml (r2 > 0.99). The recoveries at concentrations of 100, 200, 400, and 800 ng/ml were 108, 106, 91, and 89%, respectively, for ARS and were 112, 95, 80, and 86%, respectively, for DHA. For ARN, the recoveries were 119, 119, and 90% for concentrations of 200, 400, and 800 ng/ml, respectively. ARS working solutions were not stable after two months of storage at 4 degrees C or after 21 days at room temperature. This newly developed LC-MS method was then applied for measuring of ARS and DHA concentrations in a healthy volunteer having received oral ARS at 200 mg once daily for 5 consecutive days. There was no decline in ARS concentration after repeated doses and the C(ss-max-average) for DHA was found to be 703 +/- 94 ng/ml at t(ss-max) of 2 h.

Pharmacokinetics of a five-day oral dihydroartemisinin monotherapy regimen in patients with uncomplicated falciparum malaria.

The pharmacokinetics of dihydroartemisinin (DHA) in a 5-day oral monotherapy regimen was investigated in ten adult Vietnamese patients with uncomplicated falciparum malaria. The patients were treated with a total dose of 900 mg DHA divided as single daily doses of 300, 300, 100, 100, and 100 mg from day 0 through day 4. There were no differences in the concentrations of DHA within the first two days of treatment. The pharmacokinetics of DHA in the acute phase, however, was significantly different from that in the convalescent phase of malaria. Reduced half-life (T(1/2z)) and lower area under concentration curve (AUC(infinity)) values were observed on the final day of treatment in comparison to those obtained on the first day. These decreases in T(1/2z) and AUC(infinity) were observed in concordance with increased drug clearance (CL/F). Furthermore, the time required to reach maximum plasma DHA concentration (T(max)) on day 4 was shorter than that on day 0. Together, these findings suggest that the change in pharmacokinetics of DHA is related to the physiological change in malaria patients between the acute and convalescent phases of the disease.

Pharmacokinetics of mefloquine with dihydroartemisinin as 2-day regimens in patients with uncomplicated falciparum malaria.

The objective of this study was to investigate the pharmacokinetics of mefloquine (MQ) when given as 750 mg at two different times in combination regimens with dihydroartemisinin (DHA) in patients with acute uncomplicated falciparum malaria. A total of 12 Vietnamese patients (6 in each group) were randomized to receive two MQ-DHA regimens as follows: regimen-A: an initial oral dose of 300 mg DHA, followed by 750 mg MQ and 300 DHA 6 and 24 hours later; regimen-B: an initial dose of 300 mg DHA, followed by 300 mg DHA and 750 mg MQ at 24 hours. Both combination regimens were well tolerated. All patients responded well to treatment with no recrudescence during a 42 day follow-up period. The pharmacokinetics of MQ following both regimens were similar but pooled data from both groups suggest that the kinetics of MQ was different from that observed in Vietnamese healthy subjects reported in a previous study. The median (95% CI) time period for maintenance of whole blood MQ concentrations above 500 ng/ml was 16 (0-24) days. It was concluded that since no pharmacokinetic drug interaction was observed, MQ dose given 24 hours after an initial dose of DHA is a preferable combination treatment regimen with regard to patient compliance.

Anti-inflammatory effects of flavonoids from Lonicera japonica Thunb. Caprifoliaceae in combination with ?-amylase

In vitro, flavonoids from Lonicera japonica Thunb flavonoids stimulate the catalysis of hydrolysis starch. This stimulating effect depended on the concentration of Lonicera japonica flavonoid but their in vitro stimulations weren’t strong. The anti-inflammatory effects were stronger when combining flavonoid with -amylase on dextran-induced edema mouse legs. So active catalysis stimulation of -amylase could be associated with anti-inflammation process; with unclear mechanisms. This result suggested the need of further research of anti-inflammatory drugs according to combine of traditional medicine and anti-inflammatory enzyme