Investigation of Luminescence Enhancement and Decay of QD-LEDs: Interface Reactions between QDs and Atmospheres.

We investigated the current unsolved problem of short-term enhancement and long-term decay of the luminescence intensity of quantum dots (QDs)-based light-emitting diodes (LEDs) in applications for lighting and displays, and proved that the interface interaction between the QD surface and atmospheres plays a key role in the QD-LED operation process. It is suggested that the initial luminescence enhancement of QD-LEDs would be caused by the QD surface-adsorbed species, such as ligands and gas molecules, rather than QDs themselves, whereas the luminescence decay is correlated to the interface reactions between QDs and photo-generated reactive oxygen species, which leads to formations of sulfate, hydroxide, and oxide compounds after QDs are illuminated by 450 nm blue light in oxygen and water environments according to surface analysis and theoretic thermodynamic calculations. It was also found that involvement of water in the QD-LED operation can cause crystal merging of QDs possibly because of the surface sulfates in the presence of water.

An Investigation of Pharmacists' Acceptance of NHI-PharmaCloud in Taiwan.

Taiwan's National Health Insurance (NHI) is one of the most successful insurance programs in the world. The National Health Insurance Administration (NHIA) established the NHI-PharmaCloud as a platform to reduce medication duplication and other medication errors among the NHI-contracted facilities. The NHI-PharmaCloud can help pharmacists access patient medication information from the preceding 3 months to improve drug safety. The use of NHI-PharmaCloud can improve the quality of healthcare, but improvements cannot occur if pharmacists are unwilling to use the platform. Therefore, the main objective of our study is to investigate the factors affecting pharmacists' adoption of the NHI-PharmaCloud. This study develops a research model using theories of technology adoption, self-efficacy, and perceived risk and uses randomly distributed survey questionnaires to collect data from local pharmacists. The results show that self-efficacy, perceived usefulness, and perceived psychological risk are 3 critical factors that could affect pharmacists' willingness to use the NHI-PharmaCloud. The research results may also help NHIA to effectively promote the usage of the NHI-PharmaCloud in Taiwan. In addition, governments in other countries may refer to the results of this study when implementing their own PharmaCloud-type systems to improve drug safety.

Designing a Microfluidic Device with Integrated Ratiometric Oxygen Sensors for the Long-Term Control and Monitoring of Chronic and Cyclic Hypoxia.

Control of oxygen over cell cultures in vitro is a topic of considerable interest, as chronic and cyclic hypoxia can alter cell behaviour. Both static and transient hypoxic levels have been found to affect tumour cell behaviour; it is potentially valuable to include these effects in early, in vitro stages of drug screening. A barrier to their inclusion is that rates of transient hypoxia can be a few cycles/hour, which is difficult to reproduce in traditional in vitro cell culture environments due to long diffusion distances from control gases to the cells. We use a gas-permeable three-layer microfluidic device to achieve spatial and temporal oxygen control with biologically-relevant switching times. We measure the oxygen profiles with integrated, ratiometric optical oxygen sensors, demonstrate sensor and system stability over multi-day experiments, and characterize a pre-bleaching process to improve sensor stability. We show, with both finite-element modelling and experimental data, excellent control over the oxygen levels by the device, independent of fluid flow rate and oxygenation for the operating flow regime. We measure equilibration times of approximately 10 min, generate complex, time-varying oxygen profiles, and study the effects of oxygenated media flow rates on the measured oxygen levels. This device could form a useful tool for future long-term studies of cell behaviour under hypoxia.

Synthesis of directly linked diazine isosteres of pyrrole-polyamide that photochemically cleave DNA.

A distamycin model containing an isosteric diazine linked pyrrole has been designed and synthesized. The key steps of the synthesis involved the successful diazotization of the 4-amino-pyrrole derivatives to give the diazomium salts, which undergo coupling reactions with N-methylpyrrole to yield the directly linked diazine compounds. The amide isosteric-diazine pyrrole I demonstrated photo-induced DNA damage upon iradiation with UV light (365 nm). Spectrophotometric and mass spectrometric identification suggest that the azo-linkage in I did not dissociate during irradiation. Moreover, compound I produced DNase I footprints with the HexB DNA fragment at AT sites, as well as some other mixed sequences (5'-ATGTCG-3'), indicative of the additional role of the diazine-linkage for interaction at the duplex DNA.

Diastereoselective synthesis of a highly functionalized angularly substituted cis-perhydroisoquinoline-3,6-dione via organoiron.

Nitrile addition to cyclohexadienyium-Fe(CO)(3) perchlorate salt provides an efficient entry into the angularly substituted cis-fused perhydroisoquinoline ring system. The key steps in the assembly of the angularly substituted cis-octahydroisoquinoline ring are the transformation of the nitrile to an N-(benzylmethylencie)amino group and a diastereoselective intramolecular Michael reaction to form the bicyclic ring.

Propofol significantly attenuates iNOS, CAT-2, and CAT-2B transcription in lipopolysaccharide-stimulated murine macrophages.

BACKGROUND: Propofol significantly inhibits inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) biosynthesis in stimulated macrophages. L-arginine transport mediated by the isozymes of type-2 cationic amino acid transporter (including CAT-2 and CAT-2B) has been reported to play a crucial role in regulating iNOS activity. We sought to evaluate the effects of propofol on L-arginine transport and transcription of CAT-2 and CAT-2B. METHODS: Confluent murine macrophages (RAW264.7 cells) were stimulated with lipopolysaccharide (LPS) to induce NO production, L-arginine transport and the transcriptions of iNOS, CAT-2, and CAT-2B. Propofol (25, 50, and 75 microM) was added to the cells 4 hours before, immediately after, or 4 hours after LPS administration. After reacting with LPS for 18 hours, cell cultures were harvested and assayed. RESULTS: Propofol administered 4 hours before LPS had no significant effects on NO production, L-arginine transport, and the transcriptions of iNOS and CAT-2. To our surprise, NO production and iNOS transcription were significantly enhanced by 25 microM propofol administered immediately after LPS. NO production and iNOS transcription were not affected by 50 microM propofol but significantly inhibited by 75 microM propofol administered immediately after LPS. CAT-2 transcription and L-arginine transport were significantly inhibited by 50 and 75 microM but not 25 microM propofol administered immediately after LPS. When administered 4 hours after LPS, 75 but not 25 and 50 microM propofol significantly inhibited NO production, L-arginine transport, and the transcription of iNOS and CAT-2. In addition, CAT-2B transcription was significantly inhibited by propofol that was administered 4 hours before, immediately after, or 4 hours after LPS. CONCLUSIONS: Propofol had significantly inhibitory effects on LPS-induced NO production, L-arginine transport, and the expressions of iNOS, CAT-2 and CAT-2B in stimulated murine macrophages in a dose-dependent manner. In addition, timing of administration also affected this regulatory effect of propofol.