Electrically Switchable Photonic Molecule Laser

We have studied the coherent intercavity coupling of the evanescent fields of the whispering gallery modes of two terahertz quantum-cascade lasers implemented as microdisk cavities. The electrically pumped single-mode operating microcavities allow to electrically control the coherent mode coupling for proximity distances of the cavities up to 30-40 \mu\m. The optical emission of the strongest coupled photonic molecule can be perfectly switched by the electrical modulation of only one of the coupled microdisks. The threshold characteristics of the strongest coupled photonic molecule demonstrates the linear dependence of the gain of a quantum-cascade laser on the applied electric field.Comment: 4 pages, 4 figure

Differential Phosphorylation of Ribosomal Proteins in Arabidopsis thaliana Plants during Day and Night

Protein synthesis in plants is characterized by increase in the translation rates for numerous proteins and central metabolic enzymes during the day phase of the photoperiod. The detailed molecular mechanisms of this diurnal regulation are unknown, while eukaryotic protein translation is mainly controlled at the level of ribosomal initiation complexes, which also involves multiple events of protein phosphorylation. We characterized the extent of protein phosphorylation in cytosolic ribosomes isolated from leaves of the model plant Arabidopsis thaliana harvested during day or night. Proteomic analyses of preparations corresponding to both phases of the photoperiod detected phosphorylation at eight serine residues in the C-termini of six ribosomal proteins: S2-3, S6-1, S6-2, P0-2, P1 and L29-1. This included previously unknown phosphorylation of the 40S ribosomal protein S6 at Ser-231. Relative quantification of the phosphorylated peptides using stable isotope labeling and mass spectrometry revealed a 2.2 times increase in the day/night phosphorylation ratio at this site. Phosphorylation of the S6-1 and S6-2 variants of the same protein at Ser-240 increased by the factors of 4.2 and 1.8, respectively. The 1.6 increase in phosphorylation during the day was also found at Ser-58 of the 60S ribosomal protein L29-1. It is suggested that differential phosphorylation of the ribosomal proteins S6-1, S6-2 and L29-1 may contribute to modulation of the diurnal protein synthesis in plants

Development and evaluation of an emulsion containing lycopene for combating acceleration of skin aging

Licopeno é um carotenóide com potente atividade antioxidante encontrado em grande quantidade no tomate e usado no combate a diversas doenças como doenças cardiovasculares e diferentes tipos de cânceres, incluindo o câncer de próstata. O objetivo desse trabalho foi desenvolver uma emulsão contendo extrato de licopeno obtido do tomate salada e avaliar a citotoxicidade do extrato, a estabilidade, o comportamento reológico, atividade antioxidante e permeação do fitocosmético. O cosmético foi desenvolvido utilizando fase oleosa contendo derivados de Karité e submetido à avaliação da estabilidade físico-química, espalhabilidade, análise térmica, comportamento reológico, qualidade microbiológica, citotoxicidade, atividade antioxidante e testes de permeação e retenção cutânea. Os resultados demonstraram que o fitocosmético é estável, apresenta comportamento reológico desejável para uma formulação tópica e é um produto promissor para ser utilizado no combate à aceleração do envelhecimento cutâneo.Lycopene, a carotenoid and potent antioxidant is found in large quantities in tomatoes. Lycopene combats diseases, such as cardiovascular disease and different types of cancer, including prostate cancer. However, its topical use in emulsion form for the combat of skin aging is under-explored. The aim of the present study was to develop an emulsion containing lycopene extracted from salad tomatoes and evaluate its cytotoxicity, stability, rheological behavior, antioxidant activity and phytocosmetic permeation. The developed cosmetic comprised an oil phase made up of shea derivatives and was evaluated in terms of its physiochemical stability, spreadability, thermal analysis, rheological behavior, microbiological quality, cytotoxicity, antioxidant activity, cutaneous permeation and retention. The results demonstrate that this phytocosmetic is stable, exhibits satisfactory rheological behavior for a topical formula and is a promising product for combating skin aging

Development, characterization, and stability of O/W pepper nanoemulsions produced by high-pressure homogenization

Interest in the utilization of bioactive plant compounds in foods has increased due to their biochemical activities (antioxidant, antimicrobial, etc.), and as alternatives in the reduction of the use of high concentrations of chemical substances. However, some of these additives are hydrophobic, thus being harder to disperse into the food matrix, which is generally water-based. A good alternative is the use of low concentrations of these compounds as nanoemulsions. The objective of the present study was to develop oil-in-water nanoemulsions containing dedo-de-moça pepper extract for food applications. Research in the development of these nanoemulsions was carried out using a high-speed homogenizer, followed by a high-pressure homogenizer. The influence of the following parameters was assessed: type and concentration of surfactants, hidrophilic-lipophilic balance, lipid/aqueous phase ratio, surfactant/oil ratio, pepper extract composition in nanoemulsion, and processing conditions. Nanoemulsions were evaluated by environmental (centrifugal and thermal) and storage stabilities, characterized by average droplet size and -potential measurements, color, interfacial tension, atomic force, and cryo-scanning electron microscopy. Those with average droplet size between 132 ± 2.0 and 145 ± 1.0 nm were developed depending on working pressure and number of cycles; -potential was around 36.71 ± 0.62 mV and the best nanoemulsion was stable to centrifugation and most of the thermal stresses. Droplets were characterized with cryo-scanning electron microscopy as being spherical, homogeneous, and stable, and remained stable when stored at 4 °C and room temperature for over 120 days. The pepper nanoemulsion, developed in the present study, has potential applications in the food industry.The first author gratefully acknowledges the CNPq and CAPES (National Council for Scientific and Technological Development, Program Science without Boarder) for the BSWE^ PhD (Process 236877/2012-1) fellowship, and CAPES for the national PhD fellowship. The last author acknowledges the São Paulo Research Foundation (FAPESP) Brazil, for the grant (CEPID-FoRC, 2013/07914-8).info:eu-repo/semantics/publishedVersio