Sodium sulfide-promoted regiodefined redox condensation of o-nitroanilines with aryl ketones to benzo[a]phenazines and quinoxalines.

Inexpensive sodium sulfide trihydrate was found to promote unprecedented 6e-regio-predefined redox condensation of o-nitroanilines with α-tetralones to benzo[a]phenazines. The method was also successfully extended to acetophenones and higher homologs as reducing partners to provide 2-phenylquinoxalines. Compared to traditional approaches toward benzo[a]phenazine and quinoxaline cores starting with o-phenylenediamines, the present strategy could afford these heterocycles with well-defined regiochemistry based on the structure of starting o-nitroanilines.

Fe/S-Catalyzed Redox Condensation of o-Nitrophenols with Isothiocyanates to 2-Aminobenzoxazoles.

As frequently encountered byproducts of isocyanate chemistry, hydrogen sulfide and related sulfur containing compounds should be treated in a safe way to lower their adverse health and environmental effects, especially in large scale syntheses. As a proof of concept, we report herein an example of in situ recycling of sulfur byproduct to reductant in the synthesis of bioactive 2-aminobenzoxazoles 3. Using an Fe/S catalytic system, this heterocyclic scaffold could be obtained from o-nitrophenols 1 with isothiocyates 2 via direct redox condensation consisting of reduction of the nitro group of 1 by the sulfur moiety of 2.

Nanocapsule pH Regulator: Sustained Continuous Alkali Release from Thermosensitive Liposomes Reduces Acid Erosion.

Thermosensitive liposomes are major drug delivery carriers, which enable targeting of drugs and burst release of the drugs from the liposomes at the site of action by applying a local heat stimulation above body temperature. Although the burst release is significant for a one-shot high-rate release of drugs at the target site, this type of release has a limited sustained action of the drugs. In this study, we report the alkali-encapsulating thermosensitive liposomes enabling environment pH regulation by sustained continuous cargo release at human body temperature. The liposomes encapsulating alkalis successfully neutralized the environmental acids for hours by releasing the alkalis and prevented acid erosion of hydroxyapatite matrix. Taken together, the present liposomes are effective for the sustained release of cargo at body temperature, specifically the alkali-encapsulating liposomes can be a preventing agent for dental caries in the oral cavity. The sustained release under endogenous body heat characteristics of thermosensitive liposomes showcased in this study can also be extended for prolonged intravenous drug exposure from targeted liposomal drug nanotherapeutics in the near future.

Nanocapsules for Programmed Neurotransmitter Release: Toward Artificial Extracellular Synaptic Vesicles.

Nanocapsules present a promising platform for delivering chemicals and biomolecules to a site of action in a living organism. Because the biological action of the encapsulated molecules is blocked until they are released from the nanocapsules, the encapsulation structure enables triggering of the topical and timely action of the molecules at the target site. A similar mechanism seems promising for the spatiotemporal control of signal transduction triggered by the release of signal molecules in neuronal, metabolic, and immune systems. From this perspective, nanocapsules can be regarded as practical tools to apply signal molecules such as neurotransmitters to intervene in signal transduction. However, spatiotemporal control of the payload release from nanocapsules persists as a key technical issue. Stimulus-responsive nanocapsules that release payloads in response to external input of physical stimuli are promising platforms to enable programmed payload release. These programmable nanocapsules encapsulating neurotransmitters are expected to lead to new insights and perspectives related to artificial extracellular synaptic vesicles that might provide an experimental and therapeutic strategy for neuromodulation and nervous system disorders.

Neurotransmitter-Loaded Nanocapsule Triggers On-Demand Muscle Relaxation in Living Organism.

This paper reports the on-demand artificial muscle relaxation using a thermosensitive liposome encapsulating γ-aminobutyric acid (GABA) inhibitory neurotransmitter. Muscle relaxation is not feasible in principle, although muscle contraction can be easily induced by electrical stimulation. Herein, thermosensitive liposomes (phase transition temperature = 40 °C) were synthesized to encapsulate GABA and were injected into a leg of a living beetle. The leg was wrapped around by a Ni-Cr wire heater integrated with a thermocouple to enable the feedback control and to manipulate the leg temperature. The injected leg was temporarily immobilized by heating it up to 45 °C. The leg did not swing even by electrically stimulating the leg muscle. Subsequently, the leg recovered to swing. The result indicates that GABA was released from liposomes and fed to the leg muscle, enabling temporal muscle relaxation.

Some remarks on the quality of malaria parasite examination in Thanh Hoa province in 2002

In 2002, 99.807 blood slides were taken and examined in Thanh Hoa province, of which 33.464 slides were taken from fever patients (33.52%). 196 positive cases were detected. 52 microscopic points were checked, of which 10 microscopic points were very good functioning (19.23%), 27 points were good (59.9%), 12 were average and 3 were not good (5.76%). The quality of slides taken by the commune and village health workers was not so good, the slides were too thick or too thin with blood. In some villages, the slides were taken massively in order to fulfill the target. Checking the quality of microscopy showed that the mistake rate of microscopy was 13.16% as compared with the total slides sent for rechecking. In some microscopic points, the mistake rate was high (the provincial hospital had the mistake of 6/19 positive slides)