Lattice thermal expansion and anisotropic displacements in urea, bromomalonic aldehyde, pentachloropyridine and naphthalene

Anisotropic displacement parameters (ADPs) are commonly used in crystallography, chemistry and related fields to describe and quantify thermal motion of atoms. Within the very recent years, these ADPs have become predictable by lattice dynamics in combination with first-principles theory. Here, we study four very different molecular crystals, namely urea, bromomalonic aldehyde, pentachloropyridine, and naphthalene, by first-principles theory to assess the quality of ADPs calculated in the quasi-harmonic approximation. In addition, we predict both thermal expansion and thermal motion within the quasi-harmonic approximation and compare the predictions with experimental data. Very reliable ADPs are calculated within the quasi-harmonic approximation for all four cases up to at least 200 K, and they turn out to be in better agreement with experiment than the harmonic ones. In one particular case, ADPs can even reliably be predicted up to room temperature. Our results also hint at the importance of normal-mode anharmonicity in the calculation of ADPs

Oronasopharyngeal chordomas

ManuscriptBackground: Chordomas are rare tumors derived from notochordal remnants. The authors report on a series of three cases of primary familial oronasopharyngeal chordomas treated at our institution. Methods: A retrospective chart review was completed of the three cases of primary familial oronasopharyngeal chordoma treated at the University of Utah. Findings: All three patients (100%) were neurologically intact and presented with nasal obstruction. The patients ranged in age from 5 to 65 years and were first-degree relatives. None of the patients had bony erosion of the skull base on imaging, and all of the patients' tumors connected with the skull base via a tract. All three patients were treated with a wide excision combined with drilling of the involved skull base. They all tolerated the procedure without any complications and remain tumor free with a follow up of 12 months to 4.5 years. Conclusion: Primary oronasopharyngeal chordomas are rare tumors that may present without bony erosion of the skull base. A wide excision with drilling of the involved bony structures may offer an oncologic cure

Nature-Inspired, Computer-Assisted Optimization of Hierarchically Structured Zeolites

Zeolite catalysis is often affected by transport limitations, which significantly influence overall performance. Introducing wide pores as molecular transport highways can reduce transport limitations, control the product distribution, and mitigate effects of catalyst deactivation. Nevertheless, the importance to rationally design the meso‐ and macropore space remains underappreciated. This article reviews multiscale modelling approaches to optimize overall catalytic performance. It provides a general methodology and rules of thumb to guide catalyst synthesis with optimal pore network characteristics. Inspiration is taken from nature, such as the structure of leaves and tissues, with similar requirements and associated features. In optimal hierarchically structured zeolites, the added macro‐/mesopore volume fraction, connectivity, crystal size, and minimum wide pore size are crucial. The broad pore size distribution is secondary. No uncontrolled diffusion limitations should exist within the zeolite crystals. Surface barriers, however, can significantly affect, even dominate overall transport. Understanding their origin and ways to control them is an emergent research area. Synthesis methods to realize hierarchically structured zeolites are briefly reviewed. Significant gaps exist between laboratory synthesis methods and industrial requirements. Zeolite catalysis could benefit from computer‐assisted design of their hierarchical pore network, embracing principles used by natural transport networks for scalable efficiency, selectivity, and robustness

One-pot Synthesis of Hierarchical, Micro-macroporous Zeolites with Encapsulated Metal Particles as Sinter-resistant, Bifunctional Catalysts

We report a new one-pot synthesis procedure for hierarchical zeolites with intracrystalline macropores and metal particles encapsulated within the zeolitic walls. The synthesis allows to prepare macroporous zeolites of MFI topology with different heteroatoms (silicalite-1, ZSM-5 and TS-1) and different encapsulated noble metal particles, such as gold, platinum and palladium. The hierarchically structured zeolites contain large macropores with diameters around 400 nm, which are well distributed and interconnected and should significantly enhance mass transport properties. The encapsulation of metal nanoparticles within the zeolitic walls leads to remarkable sinter resistance of the particles. Encapsulated gold nanoparticles (2.6 nm) do not significantly change in size during an 18-hour treatment at 600 °C under air, while non-encapsulated gold particles sinter heavily during the same treatment. Catalytic experiments for the direct epoxidation of propene with hydrogen and oxygen show that both catalytic functions of a macroporous TS-1 sample that encapsulates gold particles are accessible and active. This catalyst displays high activity, although PO selectivity could still be improved. These materials show great potential for use in catalytic applications, due to their bifunctional nature, high sintering resistance, shape selective properties and hierarchical structure

Harmoney : semantics for FinTech

As a result of legislation imposed by the European Parliament, in order to protect inhabitants from being exposed to a too high financial risk when investing in a variety of financial markets and products, Financial Service Providers (FSPs) are obliged to test the knowledge and experience of potential investors. This is oftemtimes done by means of questionnaires. However, these questionnaires differ in style and structure from one FSP to the other. The goal of this research is to manage in a more cost-effective manner (aligned with the needs and competencies of the individual financial investor in terms of products and services) the management of the private equity and to facilitate the fine-tuned personalised financial advisory services needed. This is achieved by means of a knowledge-based approach, integrating the available information of the investor (e.g. personal profile in terms of financial knowledge and experience) and for an extendable amount of financial service providers w ith their financial products and demonstrated by a number of exemplary use case scenarios

Precisely Engineered Supported Gold Clusters as a Stable Catalyst for Propylene Epoxidation

Designing a stable and selective catalyst with high H2 utilisation is of pivotal importance for the direct gas-phase epoxidation of propylene. This work describes a facile one-pot methodology to synthesise ligand-stabilised sub-nanometre gold clusters immobilised onto a zeolitic support (TS-1) to engineer a stable Au/TS-1 catalyst. A non-thermal O2 plasma technique is used for the quick removal of ligands with limited increase in particle size. Compared to untreated Au/TS-1 catalysts prepared using the deposition precipitation method, the synthesised catalyst exhibits improved catalytic performance, including 10 times longer lifetime (>20 days), increased PO selectivity and hydrogen efficiency in direct gas phase epoxidation. The structure-stability relationship of the catalyst is illustrated using multiple characterisation techniques, such as XPS, 31P MAS NMR, DR-UV/VIS, HRTEM and TGA. It is hypothesised that the ligands play a guardian role in stabilising the Au particle size, which is vital in this reaction. This strategy is a promising approach towards designing a more stable heterogeneous catalyst

Gold nanoparticles with tailored size through ligand modification for catalytic applications

The active sites of catalysts can be tuned by using appropriate organic moieties. Here, we describe a facile approach to synthesise gold nanoparticles (AuNPs) using various Au(I) precursors. The core size of these AuNPs can be precisely tailored by varying the steric hindrance imposed by bound ligands. An interesting relationship is deduced that correlates the steric hindrance around the metal to the final size of the nanoparticles. The synthesised AuNPs are immobilised onto TS-1 zeolite (Au/TS-1) with minimal change in the final size of the AuNPs. The catalytic performance of Au/TS-1 catalyst is evaluated for the direct gas phase epoxidation of propylene with hydrogen and oxygen, an environmentally friendly route to produce propylene oxide. The results indicate that smaller AuNPs exhibit enhanced catalytic activity and selectivity. Furthermore, this synthetic approach is beneficial when tailored synthesis of gold nanoparticles of specific sizes is required

Deformation of canonical morphisms and the moduli of surfaces of general type

In this article we study the deformation of finite maps and show how to use this deformation theory to construct varieties with given invariants in a projective space. Among other things, we prove a criterion that determines when a finite map can be deformed to a one--to--one map. We use this criterion to construct new simple canonical surfaces with different $c_1^2$ and $\chi$. Our general results enable us to describe some new components of the moduli of surfaces of general type. We also find infinitely many moduli spaces $\mathcal M_{(x',0,y)}$ having one component whose general point corresponds to a canonically embedded surface and another component whose general point corresponds to a surface whose canonical map is a degree 2 morphism.Comment: 32 pages. Final version with some simplifications and clarifications in the exposition. To appear in Invent. Math. (the final publication is available at springerlink.com

Worldwide food recall patterns over an eleven month period: A country perspective.

<p>Abstract</p> <p>Background</p> <p>Following the World Health Organization Forum in November 2007, the Beijing Declaration recognized the importance of food safety along with the rights of all individuals to a safe and adequate diet. The aim of this study is to retrospectively analyze the patterns in food alert and recall by countries to identify the principal hazard generators and gatekeepers of food safety in the eleven months leading up to the Declaration.</p> <p>Methods</p> <p>The food recall data set was collected by the Laboratory of the Government Chemist (LGC, UK) over the period from January to November 2007. Statistics were computed with the focus reporting patterns by the 117 countries. The complexity of the recorded interrelations was depicted as a network constructed from structural properties contained in the data. The analysed network properties included degrees, weighted degrees, modularity and <it>k</it>-core decomposition. Network analyses of the reports, based on 'country making report' (<it>detector</it>) and 'country reported on' (<it>transgressor</it>), revealed that the network is organized around a dominant core.</p> <p>Results</p> <p>Ten countries were reported for sixty per cent of all faulty products marketed, with the top 5 countries having received between 100 to 281 reports. Further analysis of the dominant core revealed that out of the top five transgressors three made no reports (in the order China > Turkey > Iran). The top ten detectors account for three quarters of reports with three > 300 (Italy: 406, Germany: 340, United Kingdom: 322).</p> <p>Conclusion</p> <p>Of the 117 countries studied, the vast majority of food reports are made by 10 countries, with EU countries predominating. The majority of the faulty foodstuffs originate in ten countries with four major producers making no reports. This pattern is very distant from that proposed by the Beijing Declaration which urges all countries to take responsibility for the provision of safe and adequate diets for their nationals.</p

Compensation comparison method for assessment of retinal straylight,”

PURPOSE. Presently, no instrument or method exists that is generally accepted for routine clinical assessment of (functional) retinal straylight. Yet retinal straylight is the cause of major patient complaints, such as hindrance from glare and loss of contrast. It results from disturbances in the optical media that increase light-scattering over angles of 1°to 90°. Its assessment would help to decide whether to perform surgery for (early) cataract and would help in the evaluation of corneal or vitreal turbidity. METHODS. The psychophysical technique of the &quot;direct compensation&quot; method was adapted to make it suitable for routine clinical assessment. In the new approach, called &quot;compensation comparison, &quot; the central test field is subdivided into two half fields: one with and one without counterphase compensation light. The subject&apos;s task is a forced-choice comparison between the two half fields, to decide which half flickers more strongly. A theoretical form for the respective psychometric function was defined and experimentally verified in a laboratory experiment involving seven subjects, with and without artificially increased light scattering. The method was applied in a separate multicenter study. Its reliability was additionally tested with a commercial implement (C-Quant; Oculus Optikgeräte, Wetzlar-Dutenhofen, Germany). RESULTS. A repeated-measures SD of 0.07 log units was achieved, to be compared with differences in the young normal population of 0.4 log units and an increase with healthy aging by 0.5 log units at 80 years and by 1.0 or more log units with (early) cataract or corneal disturbances. Reliability was further found to be high when using the commercial version of the method. CONCLUSIONS. The compensation comparison method for measuring retinal straylight is suited for clinical use to diagnose patients with complaints caused by large angle light scattering in the eye such as early cataract. (Invest Ophthalmol Vis Sci