Synthesis and luminescent properties of star-burst D-Pi-A compounds based on 1,3,5-triazine core and carbazole end-capped phenylene ethynylene arms

Two new star-burst compounds based on 1,3,5-triazine core and carbazole end-capped phenylene ethynylene arms (1a and 1b) were synthesized and characterized. Their photophysical properties were investigated systematically via spectroscopic and theoretical methods. Both compounds exhibit strong 1π–π⁎ transitions in the UV region and intense 1π–π⁎/intramolecular charge transfer (1ICT) absorption bands in the UV–vis region. Introducing the carbazole end-capped phenylene ethynylene arm on the 1,3,5-triazine core causes a slight bathochromic shift and enhanced molar extinction coefficient of the 1π–π⁎/1ICT transition band. Both compounds are emissive in solution at room temperature and 77 K, which exhibit pronounced positive solvatochromic effect. The emitting state could be ascribed to 1ICT state in more polar solvent, and 1π–π⁎ state in low-polarity solvent. The high emission quantum yields (Φem=0.90~1.0) of 1a and 1b (in hexane and toluene) make them potential candidates as efficient light-emitting materials. The spectroscopic studies and theoretical calculations indicate that the photophysical properties of these compounds can be tuned by the carbazole end-capped phenylene ethynylene arm, which would also be useful for rational design of photofunctional materials.

Human bladder uroepithelial cells synergize with monocytes to promote IL-10 synthesis and other cytokine responses to Uropathogenic Escherichia coli

Urinary tract infections are a major source of morbidity for women and the elderly, with Uropathogenic Escherichia coli (UPEC) being the most prevalent causative pathogen. Studies in recent years have defined a key anti-inflammatory role for Interleukin-10 (IL-10) in urinary tract infection mediated by UPEC and other uropathogens. We investigated the nature of the IL-10-producing interactions between UPEC and host cells by utilising a novel co-culture model that incorporated lymphocytes, mononuclear and uroepithelial cells in histotypic proportions. This co-culture model demonstrated synergistic IL-10 production effects between monocytes and uroepithelial cells following infection with UPEC. Membrane inserts were used to separate the monocyte and uroepithelial cell types during infection and revealed two synergistic IL-10 production effects based on contact-dependent and soluble interactions. Analysis of a comprehensive set of immunologically relevant biomarkers in monocyte-uroepithelial cell co-cultures highlighted that multiple cytokine, chemokine and signalling factors were also produced in a synergistic or antagonistic fashion. These results demonstrate that IL-10 responses to UPEC occur via multiple interactions between several cells types, implying a complex role for infection-related IL-10 during UTI. Development and application of the co-culture model described in this study is thus useful to define the degree of contact dependency of biomarker production to UPEC, and highlights the relevance of histotypic co-cultures in studying complex host-pathogen interactions.

Synthesis and applications of carbon nanomaterials for energy generation and storage

The world is facing an energy crisis due to exponential population growth and limited availability of fossil fuels. Over the last 20 years, carbon, one of the most abundant materials found on earth, and its allotrope forms such as fullerenes, carbon nanotubes and graphene have been proposed as sources of energy generation and storage because of their extraordinary properties and ease of production. Various approaches for the synthesis and incorporation of carbon nanomaterials in organic photovoltaics and supercapacitors have been reviewed and discussed in this work, highlighting their benefits as compared to other materials commonly used in these devices. The use of fullerenes, carbon nanotubes and graphene in organic photovoltaics and supercapacitors is described in detail, explaining how their remarkable properties can enhance the efficiency of solar cells and energy storage in supercapacitors. Fullerenes, carbon nanotubes and graphene have all been included in solar cells with interesting results, although a number of problems are still to be overcome in order to achieve high efficiency and stability. However, the flexibility and the low cost of these materials provide the opportunity for many applications such as wearable and disposable electronics or mobile charging. The application of carbon nanotubes and graphene to supercapacitors is also discussed and reviewed in this work. Carbon nanotubes, in combination with graphene, can create a more porous film with extraordinary capacitive performance, paving the way to many practical applications from mobile phones to electric cars. In conclusion, we show that carbon nanomaterials, developed by inexpensive synthesis and process methods such as printing and roll-to-roll techniques, are ideal for the development of flexible devices for energy generation and storage – the key to the portable electronics of the future.

Effect of LiYO2 on the synthesis and pressureless sintering of Y2SiO5

Y2SiO5 has potential applications as a high-temperature structural ceramic and environmental/thermal barrier coating. In this work, we synthesized single-phase Y2SiO5 powders utilizing a solid-liquid reaction method with LiYO2 as an additive. The reaction path of the Y2O3/SiO2/LiYO2 mixture with variation in temperatures and the role of the LiYO2 additive on preparation process were investigated in detail. The powders obtained by this method have good sinterability. Through a pressureless sintering process, almost fully dense Y2SiO5 bulk material was achieved with a very high density of 99.7% theoretical.

Low-temperature synthesis and sintering of γ-Y2Si2O7

In this article, a novel pressureless solid-liquid reaction method is presented for preparation of yttrium disilicate (γ-Y2Si2O7). Single-phase γ-Y2Si2O7 powder was synthesized by calcination of SiO2 and Y2O3 powders with the addition of LiYO2 at 1400 °C for 4 h. The addition of LiYO2 significantly decreased the synthesis temperature, shortened the calcination time, and enhanced the stability of γ-Y2Si2O7. The sintering of these powders in air and O2 was studied by means of thermal mechanical analyzer. It is shown that the γ-Y2Si2O7 sintered in oxygen had a faster densification rate and a higher density than that sintered in air. Furthermore, single-phase γ-Y2Si2O7 with a density of 4.0 g/cm3 (99% of the theoretical density) was obtained by pressureless sintering at 1400 °C for 2 h in oxygen. Microstructures of the sintered samples are studied by scanning electron microscope.