Degenerately Hydrogen Doped Molybdenum Oxide Nanodisks for Ultrasensitive Plasmonic Biosensing

Plasmonic biosensors based on noble metals generally suffer from low sensitivities if the perturbation of refractive‐index in the ambient is not significant. By contrast, the features of degenerately doped semiconductors offer new dimensions for plasmonic biosensing, by allowing charge‐based detection. Here, this concept is demonstrated in plasmonic hydrogen doped molybdenum oxides (H_xMoO₃), with the morphology of 2D nanodisks, using a representative enzymatic glucose sensing model. Based on the ultrahigh capacity of the molybdenum oxide nanodisks for accommodating H⁺, the plasmon resonance wavelengths of H_xMoO₃ are shifted into visible‐near‐infrared wavelengths. These plasmonic features alter significantly as a function of the intercalated H⁺ concentration. The facile H⁺ deintercalation out of H_xMoO₃ provides an exceptional sensitivity and fast kinetics to charge perturbations during enzymatic oxidation. The optimum sensing response is found at H_1.55MoO₃, achieving a detection limit of 2 × 10^?9m at 410 nm, even when the biosensing platform is adapted into a light‐emitting diode‐photodetector setup. The performance is superior in comparison to all previously reported plasmonic enzymatic glucose sensors, providing a great opportunity in developing high performance biosensors.     

Removal of heavy metals from mine water by cyanobacterial calcification

The influence of different illumination intensities on cyanobacterial calcification induced removal of heavy metals from contaminated mine water was studied. Cyanobacterial calcification experiments were performed using a growth medium intended to simulate contaminated mine water. The results indicate that calcification can promote the removal of heavy metal ions. As the illumination intensity became stronger calcification rates increased and the removal of Zn2+ and Cd2+ became more obvious. When the illumination intensity was 10000 lux the removal of Pb2+ was the largest observed: stronger or weaker illumination reduced the amount of lead removed. The removal of three different heavy metals complies with an index function. For identical illumination intensities different ions were removed to different degrees.     

Pyroxene-Type (K,Na,Li)VO3 Solid Solutions

Phase relations in the system were studied between 600° and 350°C. All three end members have the pyroxene-type structure. Both LiVO₃ and NaVO₃ are monoclinic, whereas KVO₃ takes the orthorhombic symmetry. At 360°C, the join LiVO₃–NaVO₃ is characterized by two series of pyroxene-type solid solutions: NaVO₃–(Na_0.44Li_0.56)VO₃ and LiVO₃-(Na_0.16Li_0.84)-VO₃. (K_0.5Na_0.5)VO₃ and (K_0.5Li_0.5)VO₃ are two other stable phases at 360°C. The pyroxene-type (K_0.5Na_0.5)VO₃ has a range of solid solution from (K_0.6Na_0.4)VO₃ to (K_0.4Na_0.6)VO₃ along the join and extends into the ternary field with a maximum of 13 mol% LiVO₃. (K_0.5Li_0.5)VO₃ has no detectable range of solid solution, and its X-ray powder diffraction data cannot be indexed based upon either the monoclinic or the orthorhombic unit cell.     

Electrical properties of composites as affected by the degree of mixedness of the conductive filler in the polymer matrix

The development of the electrical properties of composites as a function of the degree of mixedness of a conductive filler distributed into an insulating polymer is investigated. A wide‐angle X‐ray diffraction (WAXD)‐based quantitative phase analysis method was used to characterize the variations of the concentrations of the insulating binder and the conductive particles around their mean values as a function of mixing time in an intensive batch mixer. Increasing the time and hence, the specific energy input, during the mixing process results in a more homogeneous spatial distribution of the conductive filler in the polymeric matrix, which in turn results in a decrease of the volume conductivity of the composite. The decreasing conductivity of the composite is attributed to the better coating and hence the isolation of the conductive particles from each other, thus hindering the formation of a conductive network “percolation”. Overall, these results suggest that the control of the electrical properties of conductive composites could benefit from a good understanding and adequate control of the dynamics of the mixing process and the resulting degree of mixedness of the conductive particles in the polymer matrix.     

A spatially explicit framework for climate adaptation

Cities increasingly confront climate change-related problems of flooding, urban heat island effects, and the impact of drought on vegetation. There is a need for urban water and infrastructure planners to be able to identify vulnerable areas and to design, compare and evaluate interventions to address these problems. In response to this need, we developed the Integrated Climate Adaptation Model (ICAM), which is a Web-GIS tool based on a spatially explicit framework. ICAM has a user-friendly interface for use by a wide range of urban planning and design professionals. The tool is built on high-resolution spatial datasets, allowing users to identify critical areas that may be impacted by sea-level rise, drought, flooding, temperature increases and threats to tree heath and to consider the benefits of various grey and green infrastructure interventions. The tool is suitable for planning and evaluating interventions and to identify pathways for further desktop modelling.     

Characteristics and treatability of oil-bearing wastes from aluminum alloy machining operations

Enomoto Industry Co., exclusively uses water-based cutting fluids in its aluminum alloy machining operations. Since the cost of disposal can be much greater than the cost of purchase, the treatability of spent cutting fluids is becoming a major criterion for cutting fluid selection. Samples were collected from the machining lines at Enomoto's facility to determine their characteristics and evaluate their treatability with centrifugation, chemical coagulation and electrochemical coagulation. As expected, oil and grease (O&G) and total suspended solids (TSS) are the main reasons that spent cutting fluids are prohibited from being discharged into local swage systems. The average O&G found in the spent cutting fluids is 87,354 mg/L with TSS of more than 70,000 mg/L. Both O&G and TSS are the major contributors to the high turbidity of these waste effluents. A centrifuge with a relative centrifugal force of 1318 x g, was able to reduce 60% of the turbidity. By adding the coagulant aluminum chloride, the oil-water emulsion was destabilized, and the turbidity was reduced from 3249 Formazin Attenuation Units (FAU) to around 314 FAU. With freshly generated aluminum ions in the spent cutting fluid, the electrochemical process destabilized the oil-water emulsion system. The coalesced oil droplets were adsorbed onto the highly dispersed aluminum coagulant. The oil-rich sludge that was generated in the operation was then floated to the surface, forming a blanket that was removed by skimming. The electrochemical treatment was able to reduce the turbidity to less than 14 FAU, which is the detection limit of the Hach DR/4000 UV-vis spectrophotometer.     

Identification and quantitation of changes in the platelet activating factor family of glycerophospholipids over the course of neuronal differentiation by high-performance liquid chromatography electrospray ionization tandem mass spectrometry

Glycerophospholipids are important structural lipids in membranes with changes associated with progressive neurodegenerative disorders such as Alzheimer disease. Synthesis of the platelet activating factor (PAF) glycerophospholipid subclass is implicated in the control of neuronal differentiation and death. In this article, we combine nanoflow HPLC and mass spectrometry to screen, identify, and quantitate changes in glycerophospholipid subspecies, specifically PAF family members, over the course of neuronal differentiation. Furthermore, precursor ion scans for fragments characteristic of PAF phosphocholine family members and the standard additions of PAF subspecies were combined to perform absolute quantitation of PAF lipids in undifferentiated and differentiated PC12 cells. Surprisingly, a marked asymmetry was detected in the two predominant PAF species (C16:0, C18:0) over the course of differentiation. These results describe a new technique for the sensitive analysis of lipids combining nanoflow HPLC, ESI-MS, and precursor ion scan. Limits of detection of as little as 2 pg of PAF and LPC were obtained, and analysis of the lipidome of as little as 70,000 cells was performed on this system. Furthermore, application to the PC12 model identified a quantifiable difference between PAF molecular species produced over the course of neuronal differentiation.     

Polyarene‐Functionalized Fullerenes in Carbon Nanotubes: Towards Controlled Geometry of Molecular Chains

Mechanisms for controlling the assembly of molecular arrays in carbon nanotubes via alteration of the size and geometry of the functional groups attached to the molecules inserted into the nanotubes are studied. As model compounds, a series of structurally related fullerenes functionalized with polyaryl groups (C₆₀X, where X is a polyaryl group) of various lengths are synthesized to explore this effect. These molecules are inserted into single‐walled carbon nanotubes (SWNTs) under mild conditions to prevent their decomposition and to form C₆₀X@SNWT structures. The molecular chains thus formed are studied by high‐resolution transmission electron microscopy, X‐ray diffraction, and Raman spectroscopy, revealing that the functional groups increase the interfullerene separation proportionally with the size of X. However, the functional groups themselves appear to adopt various orientations with respect to each other and exhibit intermolecular π–π interactions within the cavities of the carbon nanotubes. All these effects create a distribution of observed interfullerene separations in nanotubes, which are examined by theoretical simulations and interpreted in terms of molecular geometries and intermolecular interactions.