99 research outputs found
Convenient synthesis of C5(CD3)5H. synthesis and characterisation of Fe{n5-C5(CD3)5}2
Journal ArticleThe large scale synthesis of deuterio(pentamethylcyclopentadiene), C5(CD3)5H ([2H30]Cp*H), and subsequent synthesis of [2H30][Fe(n|-Cp*)2] is described, together with i.r., Raman, and solid state 2H n.m.r. spectroscopic characterisation
Simultaneous differential scanning calorimetry â synchrotron X-ray powder diffraction : a powerful technique for physical form characterisation in pharmaceutical materials
© 2016 American Chemical Society. We report a powerful new technique: hyphenating synchrotron X-ray powder diffraction (XRD) with differential scanning calorimetry (DSC). This is achieved with a simple modification to a standard laboratory DSC instrument, in contrast to previous reports which have involved extensive and complex modifications to a DSC to mount it in the synchrotron beam. The high-energy X-rays of the synchrotron permit the recording of powder diffraction patterns in as little as 2 s, meaning that thermally induced phase changes can be accurately quantified and additional insight on the nature of phase transitions obtained. Such detailed knowledge cannot be gained from existing laboratory XRD instruments, since much longer collection times are required. We demonstrate the power of our approach with two model systems, glutaric acid and sulfathiazole, both of which show enantiotropic polymorphism. The phase transformations between the low and high temperature polymorphs are revealed to be direct solid-solid processes, and sequential refinement against the diffraction patterns obtained permits phase fractions at each temperature to be calculated and unit cell parameters to be accurately quantified as a function of temperature. The combination of XRD and DSC has further allowed us to identify mixtures of phases which appeared phase-pure by DSC
Exchange of coordinated solvent during crystallisation of a metal-organic framework observed by in situ high energy X-ray diffraction
Using time-resolved monochromatic high energy X-ray diffraction, we present an in situ study of the solvothermal crystallisation of a new MOF [Yb2(BDC)3(DMF)2]â
H2O (BDC=benzene-1,4-dicarboxylate and DMF=N,N-dimethylformamide) under solvothermal conditions, from mixed water/DMF solvent. Analysis of high resolution powder patterns obtained reveals an evolution of lattice parameters and electron density during the crystallisation process and Rietveld analysis shows that this is due to a gradual topochemical replacement of coordinated solvent molecules. The water initially coordinated to Yb3+ is replaced by DMF as the reaction progresses
Views from the coalface: chemo-sensors, sensor networks and the semantic sensor web
Currently millions of sensors are being deployed in sensor networks across the world. These networks generate vast quantities of heterogeneous data across various levels of spatial and temporal granularity. Sensors range from single-point in situ sensors to remote satellite sensors which can cover the globe. The semantic sensor web in principle should allow for the unification of the web with the real-word. In this position paper, we discuss the major challenges to this unification from the perspective of sensor developers (especially chemo-sensors) and integrating sensors data in real-world deployments. These challenges include: (1) identifying the quality of the data; (2) heterogeneity of data sources and data transport methods; (3) integrating data streams from different sources and modalities (esp. contextual information), and (4) pushing intelligence to the sensor level
Monitoring and validating the transport of waste
The illegal disposal of waste is a growing problem in many countries of the Organization for Economic Cooperation and Development. A weakness with the conventional waste- management cycle concerns the validation and integrity of the transportation process, from collection at industrial premises to delivery at a licenced waste-disposal facility. The on-going Waste Augmentation and Integrated Shipment Tracking (Waist) project, at CLARITY: Centre for Sensor Web Technologies, focuses on this very problem. Waist integrates a triptych of sensing technologies in addressing this problem
Immunity induced by a broad class of inorganic crystalline materials is directly controlled by their chemistry
There is currently no paradigm in immunology that enables an accurate prediction of how the immune system will respond to any given agent. Here we show that the immunological responses induced by members of a broad class of inorganic crystalline materials are controlled purely by their physicochemical properties in a highly predictable manner. We show that structurally and chemically homogeneous layered double hydroxides (LDHs) can elicit diverse human dendritic cell responses in vitro. Using a systems vaccinology approach, we find that every measured response can be modeled using a subset of just three physical and chemical properties for all compounds tested. This correlation can be reduced to a simple linear equation that enables the immunological responses stimulated by newly synthesized LDHs to be predicted in advance from these three parameters alone. We also show that mouse antigen-specific antibody responses in vivo and human macrophage responses in vitro are controlled by the same properties, suggesting they may control diverse responses at both individual component and global levels of immunity. This study demonstrates that immunity can be determined purely by chemistry and opens the possibility of rational manipulation
Structural variety in ytterbium dicarboxylate frameworks and in situ study diffraction of their solvothermal crystallisation
Structural, electronic and kinetics on organometallic intercalates of metal dichalcogenides
in situ kinetics experiments are general and permit dynamic structural
transformations in air- and moisture-sensitive suspensions of solids to be effectively studied
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