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Clean water for human consumption is, in many places, a scarce resource, and efficient schemes to purify water are in great demand. Here, we describe a method to dramatically increase the efficiency of a photocatalytic water purification microreactor. Our hierarchical optofluidic microreactor combines the advantages of a nanostructured photocatalyst with light harvesting by base substrates, together with a herringbone micromixer for the enhanced transport of reactants. The herringbone micromixer further improves the reaction efficiency of the nanostructured photocatalyst by generating counter-rotating vortices along the flow direction. In addition, the use of metal-based substrates underneath the nanostructured catalyst increases the purification capacity by improving the light-harvesting efficiency. The photocatalyst is grown from TiO2 as a nanohelix film, which exhibits a large surface-to-volume ratio and a reactive microstructure. We show that the hierarchical structuring with micro- to nanoscale features results in a device with markedly increased photocatalytic activity as compared with a solid unstructured catalyst surface. This is evidenced by the successful degradation of persistent aqueous contaminants, sulfamethoxazole, and polystyrene microplastics. The design can potentially be implemented with solar photocatalysts in flow-through water purification systems. [ABSTRACT FROM AUTHOR]

Indoor air quality, especially in terms of particulate matter (PM), is a critical public health concern. Although various methods for removing indoor PM have been suggested, the effects of various influential factors on PM deposition have not been clearly understood. Here, the effect of the flow structure inside a test chamber on PM deposition was quantitatively investigated using flow visualization techniques. To elucidate the flow parameters that influence the PM deposition, the efficiency of PM removal and deposition constant were examined for different flow directions, flow velocities, and distances between the fan and the surface of the test chamber. The spatial distributions of the mean velocity and turbulence intensity inside the test chamber were obtained experimentally using a particle image velocimetry technique to understand the mechanism associated with PM deposition. The overall mean velocity, recirculating flow region, and turbulent intensity in the near-wall regions may partially explain the difference in the PM deposition under various flow conditions. [ABSTRACT FROM AUTHOR]

Recently, the multi-needle drug injection has been adopted to overcome the shortcomes of conventional single-needle injection, enhancing the efficiency of drug delivery. However, the effect of needle array on the efficacy of drug delivery has not been fully elucidated. In this study, the interactions of drug analogous solution injected from a pair of needles were analyzed to examine the design criteria of effective multi-needle devices for drug delivery. Temporal and spatial variations of relative contents of the solution in the tissues were compared according to the distance between two adjacent needles (DN). As the DN increases from 5 to 20 D, where D is the needle diameter, the solution from each needle encounters 3.5 times faster, and 4.22 times more solution was accumulated. At the same time, the effective spreading area was continuously increased from 54.2 to 177.8 mm2 and RCS gradient decreases from 0.087 to 0.037, due to the overlapping effect of the spreading solution from neighboring needles. Finally, based on the experimental results, an optimal design criterion of needle array for effective drug delivery was proposed. The present results would be helpful in the design of multi-needle injection devices and eventually offer advantage to patients with effective drug delivery. [ABSTRACT FROM AUTHOR]

Mass transport in porous materials is widespread in nature, and its usefulness attracts large attention for engineering applications. Plant leaves have nano-/microporous structures to pull water from root to the tip of leaves, and they finally release water to the air. In this hydraulic phenomenon called transpiration, plant leaves provide the main driving force for water transport in plants without any mechanical pump system. The morphological structure of plant leaves has been optimized through a long history of evolution to adapt to the environmental changes. In this aspect, we focus on the morphological features of plant leaves, which probably enhance leaf transpiration. The tissue organization in the hydraulic pathways inside the leaves for transpiration was investigated in this study. Inspired by the morphological structure of mesophyll cells in a plant, two analogous models were fabricated using hydrogel to study the effect of pore size on water transport. One model had nanoporous unitary structure, and the other had nano-/microporous hierarchical structure. As a result, the hydrogel model with nano-/microporous hierarchical structure induced higher evaporation and greater swelling ratio, compared with the model with nanoporous unitary structure. X-ray images of the water transport in the hydrogel models show that the porous structures of mesophyll cells can generate the Laplace pressure at the water-air interface in the air spaces. [ABSTRACT FROM AUTHOR]

Despite the increased attention to corporate social responsibility (CSR) and regulatory changes in recent years, little is known about how apparel companies are implementing and communicating CSR practices to their stakeholders. To fill the gap, this study investigated the range and strategies of leading apparel specialty retailers' CSR practices as communicated on their websites over a longitudinal period of 1 year. In total, 17 apparel specialty retailers were included in the analysis. The companies' websites were content-analyzed in-depth using the coding criteria focusing on labor and environmental issues developed for this study. The initial data were collected in November 2011 and the study was replicated in December 2012 to examine any changes in the CSR practices. As of 2011 only nine companies addressed CSR issues on their websites at different degrees despite their leadership positions in the industry. Environmental issues were addressed by only five companies, with different ranges of practices. In 2012, all 17 companies addressed labor issues on their websites with varying degrees of specificity. In terms of environmental issues, six companies (an increase of one company from 2011) addressed environmental initiatives on their websites with wider ranges of practices. Discussed are problems and opportunities, as well as the role of the government and stakeholders, for the effective communications of CSR policies and initiatives for the apparel industry. [ABSTRACT FROM AUTHOR]

Angiogenesis requires co-ordination of multiple signalling inputs to regulate the behaviour of endothelial cells (ECs) as they form vascular networks. Vascular endothelial growth factor (VEGF) is essential for angiogenesis and induces downstream signalling pathways including increased cytosolic calcium levels. Here we show that transmembrane protein 33 (tmem33), which has no known function in multicellular organisms, is essential to mediate effects of VEGF in both zebrafish and human ECs. We find that tmem33 localises to the endoplasmic reticulum in zebrafish ECs and is required for cytosolic calcium oscillations in response to Vegfa. tmem33-mediated endothelial calcium oscillations are critical for formation of endothelial tip cell filopodia and EC migration. Global or endothelial-cell-specific knockdown of tmem33 impairs multiple downstream effects of VEGF including ERK phosphorylation, Notch signalling and embryonic vascular development. These studies reveal a hitherto unsuspected role for tmem33 and calcium oscillations in the regulation of vascular development. Calcium signalling downstream of VEGF is essential for VEGF-induced angiogenesis. Here Savage et al. show that Transmembrane Protein 33 (TMEM33) is required for angiogenesis and the endothelial calcium response to VEGF, revealing a function for TMEM33 in multicellular organisms. [ABSTRACT FROM AUTHOR]

Pine cones fold their scales when it rains to prevent seeds from short-distance dispersal. Given that the scales of pine cones consist of nothing but dead cells, this folding motion is evidently related to structural changes. In this study, the structural characteristics of pine cones are studied on micro-/macro-scale using various imaging instruments. Raindrops fall along the outer scales to the three layers (bract scales, fibers and innermost lignified structure) of inner pine cones. However, not all the layers but only the bract scales get wet and then, most raindrops move to the inner scales. These systems reduce the amount of water used and minimize the time spent on structural changes. The result shows that the pine cones have structural advantages that could influence the efficient motion of pine cones. This study provides new insights to understand the motion of pine cones and would be used to design a novel water transport system. [ABSTRACT FROM AUTHOR]