Chemical speciation and bioaccessibility of arsenic and chromium in chromated copper arsenate-treated wood and soils

This research compares the As and Cr chemistry of dislodgeable residues from chromated copper arsenate (CCA)-treated wood collected by two different techniques (directly from the board surface either by rubbing with a soft bristle brush or by rinsing from human hands after contact with CCA-treated wood) and demonstrates that these materials are equivalent in terms of both the chemical form and bonding of As and Cr and in terms of the As leaching behavior. This finding links the extensive chemical characterization and bioavailability testing that has been done previously on the brush-removed residue to a material that is derived from human skin contact with CCA-treated wood. Additionally, this research characterizes the arsenic present in biological fluids (sweat and simulated gastric fluid) following contact with these residues. The data demonstrate that in biological fluids the arsenic is present primarily as free arsenate ions. Arsenic-containing soils were also extracted into human sweat to evaluate the potential for arsenic dissolution from soils at the skin surface. For soils from field sites, only a small fraction of the total arsenic is soluble in sweat. Based on comparisons to reference materials that have been used for in vivo dermal absorption studies, these findings suggest that the actual relative bioavailability via dermal absorption of As from CCA residues and soil may be well below the current default value of 3% used by U.S. EPA.     

Functional food components of Antigonon leptopus tea

The tubers and flowers of Antigonon leptopus, belonging to the family Polygonaceae, are consumed as food in several parts of the world. The aerial portion, including flowers, is used in the preparation of tea used as a cold remedy. This prompted us to investigate its functional food qualities and found that the methanol extract of the aerial parts of A. leptopus, inhibited lipid peroxidation (LPO) by 89% and cyclooxygenase enzymes, COX-1 and COX-2 by 50.4% and 72.5%, respectively, at 250 μg/ml. Purification of the methanolic extract yielded n-hentriacontane (1), ferulic acid (2), 4-hydroxycinnamic acid (3), quercetin-3-rhamnoside (4), and kaempherol-3-glucoside (5) along with β-sitosterol, β-sitosterol-glucoside and d-mannitol. Compounds 3, 4 and 5 inhibited LPO by 19.5%, 41.0%, and 60.5%, respectively, at 5 μg/ml. Similarly, compounds 3, 4 and 5 inhibited COX-1 enzyme by 64.7%, 16.9%, and 38.5% and COX-2 enzyme by 87.4%, 88.8%, and 90.2%, respectively, at 25 μg/ml. Compounds 3, 4 and 5 showed 50% inhibition (IC₅₀) at 17.4%, 68.9% and 36.3 μg/ml, against COX-1 and 8.57%, 7.86% and 6.78 μg/ml for COX-2, respectively. This is the first report of the isolation of compounds 2–5 from A. leptopus and their LPO and COX inhibitory activities.     

Synthesis and Structural Characterization of Macrocyclic Plasmin Inhibitors

Two series of macrocyclic plasmin inhibitors with a C-terminal benzylamine group were synthesized. The substitution of the N-terminal phenylsulfonyl group of a previously described inhibitor provided two analogues with sub-nanomolar inhibition constants. Both compounds possess a high selectivity against all other tested trypsin-like serine proteases. Furthermore, a new approach was used to selectively introduce asymmetric linker segments. Two of these compounds inhibit plasmin with K_i values close to 2 nM. For the first time, four crystal structures of these macrocyclic inhibitors could be determined in complex with a Ser195Ala microplasmin mutant. The macrocyclic core segment of the inhibitors binds to the open active site of plasmin without any steric hindrance. This binding mode is incompatible with other trypsin-like serine proteases containing a sterically demanding 99-hairpin loop. The crystal structures obtained experimentally explain the excellent selectivity of this inhibitor type as previously hypothesized.     

Encapsulation and Delivery of an Osteosarcoma Stem Cell Active Gallium(III)-Diflunisal Complex Using Polymeric Micelles

Here we report the encapsulation of an osteosarcoma stem cell (OSC) potent gallium(III)-diflunisal complex 1 into polymeric nanoparticles, and its delivery into osteosarcoma cells. At the optimum feed (20 %, 1 NP²⁰ ), nanoparticle encapsulation of 1 enhances potency towards bulk osteosarcoma cells and OSCs (cultured in monolayer and three-dimensional systems). Strikingly, the nanoparticle formulation exhibits up to 5645-fold greater potency towards OSCs than frontline anti-osteosarcoma drugs, doxorubicin and cisplatin. The nanoparticle formulation evokes a similar mechanism of action as the payload, which bodes well for future translation. Specifically, the nanoparticle formulation induces nuclear DNA damage, cyclooxygenase-2 downregulation, and caspase-dependent apoptosis. To the best of our knowledge, this is the first study to demonstrate that polymeric nanoparticles can be used to effectively deliver an OSC-active metal complex into osteosarcoma cells.     

Strengthening the ‘bio’ in biome: Living river biomes as a concept to leverage public engagement for river health

This Perspective argues for an expansion of conventional concepts of river biomes to better encapsulate the emerging social understanding of ‘biomes’ as living systems with unique macro- and micro-biotic ecological and biological signatures. We approach this by firstly examining recent interpretations of river biomes that have evolved from original zonal conceptions. We then postulate on the social/public understanding on ‘biomes’ through the popularity of two rich debates: human health via gut microbiomes and soil health via the soil microbiome. With these concepts in mind, we define the river biome as ‘A living flowing aquatic ecosystem, indicative of its environmental context, comprising unique biological, ecological, hydrologic and health characteristics that shape and are shaped by macro- and micro-biotic signatures and functions’. With this definition the term river biome is more aligned with ideas of river health and ecosystem functioning, which we believe may evoke greater public understanding of rivers as complex living systems. Enhanced public understanding of complex natural systems should be encouraged as a means by which to propel policy, funding and research as well as to improve specialist to non-specialist communication and relations.     

A novel method of improving energy efficient QoS in FANET using Correlation And Confidence Based Gradient Clustering Metric approach

Flying Ad-hoc Networks (FANETs) being the most popular wing of the research in recent time had many evolutions to cope up with the growing demands in defense and other civil applications. Limited number of nodes, limited source of energy and increased mobility of the drones were the major problems to be addressed while building an effective FANET. Drones were aerial-nodes that are driver-less; their actions were prescribed by means of algorithms devoid of some human relations and could be easily deployed in the system. Hence this article aims to propose a novel framework to improvise the energy efficiency of FANET through Correlation and Confidence based Gradient Clustering Metric (CC-GCM) approach in the clustering algorithm. The results obtained through the proposed model are proven to be outstanding by producing an improvised performance efficiency and augmented energy efficiency. This article also involves a comparative study of the performance attributes with the existing models with tabulated values and graphs in terms of energy consumption, average end-to-end delay, cluster building time, average cluster life time, and Packet Delivery Ratio (PDR).     

Belt furnace gettering and passivation of n‐web silicon for high‐efficiency screen‐printed front‐surface‐field solar cells

Six different resistivities (0.32, 0.57, 1.2, 2.2, 9.1 and 20 Ω cm) were investigated to understand the dopant–defect interaction in n‐type, antimony‐doped, dendritic web silicon ribbon, and to study its response to gettering and passivation during belt furnace processing (BFP). The as‐grown lifetime was found to be a strong function of resistivity with higher resistivity displaying higher lifetime. Phosphorus gettering at 925° C/6 min raised the as‐grown lifetime of ∼1 μs in 20 Ω cm n‐web to 5.4 μs. A combination of phosphorus gettering followed by simultaneous Al gettering and SiN hydrogenation raised the 20 Ω cm n‐web lifetime to 78 μs. Unlike the as‐grown web, the processed lifetime was greater than 75 μs for all resistivities, with no clear doping dependence. This is attributed to the very effective gettering and passivation during the belt furnace processing. Front surface field (FSF) n⁺–n–p⁺ cells were fabricated by spin‐on phosphorus diffusion on the front and screen‐printed Al on the back. A lifetime value of over 100 μs was obtained in a 14.2% screen‐printed FSF n‐web solar cell fabricated on 100‐μm‐thick 20 Ω cm substrate. The screen‐printed FSF cell fabricated on (111) FZ gave an efficiency of 14.9% with a fill factor of 77.6%. These results are supported by model calculations, which revealed a maximum efficiency of ∼15% for 100‐μm‐thick planar screen‐printed FSF cells and their insensitivity to bulk lifetime above 60 μs. Copyright © 2001 John Wiley & Sons, Ltd.