138 research outputs found

    A methodology for aggregate assembly modelling and planning

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    The introduction of Concurrent Engineering highlights the need for a link between the early stages of product design and assembly planning. This thesis presents aggregate assembly process planning as a novel methodology to provide this link. The theory behind the research is to bring all aspects of product development together to consider assembly planning at the conceptual stage of design. Decisions taken during the early design stage not only have the greatest influence on production times and costs, but also should ensure that a design is easy to manufacture and assemble. An automated computer-based system has been developed to implement the methodology. The system generates aggregate assembly process plans which give details of feasible sequences, assembly process times and costs, resource requirements, and factory loadings. The Aggregate Assembly Modelling and Planning (AAMP) system employs object-oriented modelling techniques to represent designs, process planning knowledge, and assembly resources. The minimum information requirements have been identified, and a product model encompassing this data has been developed. An innovative factor of this thesis is to employ Assembly Feature Connections (AFCs) within the product model to represent assembly connectivity. Detailed generic assembly process models, functioning with limited design data, are used to calculate assembly criteria. The introduction of a detailed resource model to represent assembly facilities enables the system to calculate accurate assembly times, dependent on which resources are used within a factory, or even which factory is employed. A new algorithm uses the structure of the product model, process constraints and assembly rules to efficiently generate accurate assembly sequences. Another new algorithm loads the assembly operations onto workstations, ensuring that the capability and capacity are available. The aggregate assembly process planning functionality has been tested using products from industry, and has yielded accurate results that prove to be both technically feasible and realistic. Industrial response has been extremely favourable. Specific comments on the usefulness and simplicity of such a comprehensive system gives encouragement to the concept that aggregate assembly process planning provides the required link between the early stages of product design and assembly planning

    Non-invasive patient-controlled analgesia in the management of acute postoperative pain in the hospital setting

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    Objective: Acute postoperative pain is experienced by the majority of hospitalized patients undergoing surgical procedures, with many reporting inadequate pain relief and/or high levels of dissatisfaction with their pain management. Patient-controlled analgesia (PCA) ensures patient involvement in acute pain control, a key component for implementing a quality management system. This narrative article overviews the clinical evidence for conventional PCA and briefly discusses new, non-invasive PCA systems, namely the sufentanil sublingual tablet system (SSTS) and the fentanyl iontophoretic transdermal system (FITS). Methods: A Medline literature search (patient-controlled analgesia and acute postoperative pain) was conducted to 1 April 2017; results from the main clinical trials are discussed. Additional literature was identified from the reference lists of cited publications. Results: Moderate to low quality evidence supports opioid-based intravenous PCA as an efficacious alternative to non-patient-controlled systemic analgesia for postoperative pain. However, despite the benefits of PCA, conventional intravenous PCA is limited by system-, drug- and human-related issues. The non-invasive SSTS and FITS have demonstrated good efficacy and safety in placebo- and intravenous morphine PCA-controlled trials, and are associated with high patient/healthcare practitioner satisfaction/ease of care ratings and offer early patient mobilization. Conclusions: Evidence-based guidelines for acute postoperative pain management support the use of multimodal regimens in many situations. As effective and safe alternatives to conventional PCA, and with the added benefits of being non-invasive, easy to use and allowing early patient mobilization, the newer PCA systems may complement multimodal approaches, or potentially replace certain regimens, in hospitalized patients with acute postoperative pain.Peer reviewe

    12-Eth­oxy-2,3,8,9-tetra­methoxy­benzo[c]phenanthridine dichloro­methane solvate

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    The title compound, C23H23NO5·CH2Cl2, was obtained via the alkyl­ation of the 12-hydr­oxy-2,3,8,9-tetra­methoxy­benzo[c]phenanthridine salt. The benzo[c]phenanthridine ring system is essentially planar, with a mean out-of-plane deviation of 0.026 Å. A dicloromethane mol­ecule of solvation is present and located between the sheets of phenanthridine mol­ecules, preventing any significant inter­molecular hydrogen-bonding or π–π inter­actions

    Computer-controlled apparatus for automated development of continuous flow methods

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    An automated apparatus to assist in the development of analytical continuous flow methods is described. The system is capable of controlling and monitoring a variety of pumps, valves, and detectors through an IBM PC-AT compatible computer. System components consist of two types of peristaltic pumps (including a multiple pump unit), syringe pumps, electrically and pneumatically actuated valves, and an assortment of spectrophotometric and electrochemical detectors. Details of the interface circuitry are given where appropriate. To demonstrate the utility of the system, an automatically generated response surface is presented for the flow injection determination of iron(II) by its reaction with 1,10-phenanthroline

    Ultra-low temperature structure determination of a Mn12 single-molecule magnet and the interplay between lattice solvent and structural disorder

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    We have determined the ultra-low temperature crystal structure of the archetypal single-molecule magnet (SMM) [Mn12O12(O2CMe)16(H2O)4]·4H2O·2MeCO2H (1) at 2 K, by using a combination of single-crystal X-ray and single-crystal neutron diffraction. This is the first structural study of any SMM in the same temperature regime where slow magnetic relaxation occurs. We reveal an additional hydrogen bonding interaction between the {Mn12} cluster and its solvent of crystallisation, which shows how the lattice solvent transmits disorder to the acetate ligands in the {Mn12} complex. Unusual quantum properties observed in 1 have long been attributed to disorder. Hence, we studied the desolvation products of 1, in order to understand precisely the influence of lattice solvent on the structure of the cluster. We present two new axially symmetric structures corresponding to different levels of desolvation of 1, [Mn12O12(O2CMe)16(H2O)4]·4H2O (2) and [Mn12O12(O2CMe)16(H2O)4] (3). In 2, removal of acetic acid of crystallisation largely resolves positional disorder in the affected acetate ligands, whereas removal of lattice water molecules further resolves the acetate ligand disorder in 3. Due to the absence of acetic acid of crystallisation, both 2 and 3 have true, unbroken S4 symmetry, showing for the first time that it is possible to prepare fully axial Mn12–acetate analogues from 1, via single-crystal to single-crystal transformations

    The genome sequence of the European golden eagle, Aquila chrysaetos chrysaetos Linnaeus 1758.

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    We present a genome assembly from an individual female Aquila chrysaetos chrysaetos (the European golden eagle; Chordata; Aves; Accipitridae). The genome sequence is 1.23 gigabases in span. The majority of the assembly is scaffolded into 28 chromosomal pseudomolecules, including the W and Z sex chromosomes

    The genome sequence of the Norway rat, Rattus norvegicus Berkenhout 1769.

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    We present a genome assembly from an individual male Rattus norvegicus (the Norway rat; Chordata; Mammalia; Rodentia; Muridae). The genome sequence is 2.44 gigabases in span. The majority of the assembly is scaffolded into 20 chromosomal pseudomolecules, with both X and Y sex chromosomes assembled. This genome assembly, mRatBN7.2, represents the new reference genome for R. norvegicus and has been adopted by the Genome Reference Consortium

    Focused HLA analysis in Caucasians with myositis identifies significant associations with autoantibody subgroups

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    Objectives: Idiopathic inflammatory myopathies (IIM) are a spectrum of rare autoimmune diseases characterised clinically by muscle weakness and heterogeneous systemic organ involvement. The strongest genetic risk is within the major histocompatibility complex (MHC). Since autoantibody presence defines specific clinical subgroups of IIM, we aimed to correlate serotype and genotype, to identify novel risk variants in the MHC region that co-occur with IIM autoantibodies. Methods: We collected available autoantibody data in our cohort of 2582 Caucasian patients with IIM. High resolution human leucocyte antigen (HLA) alleles and corresponding amino acid sequences were imputed using SNP2HLA from existing genotyping data and tested for association with 12 autoantibody subgroups. Results: We report associations with eight autoantibodies reaching our study-wide significance level of p<2.9x10(-5). Associations with the 8.1 ancestral haplotype were found with anti-Jo-1 (HLA-B*08:01, p=2.28x10(-53) and HLA-DRB1*03:01, p=3.25x10(-9)), anti-PM/Scl (HLA-DQB1*02:01, p=1.47x10(-26)) and anti-cN1A autoantibodies (HLA-DRB1*03:01, p=1.40x10(-11)). Associations independent of this haplotype were found with anti-Mi-2 (HLA-DRB1*07:01, p=4.92x10(-13)) and anti-HMGCR autoantibodies (HLA-DRB1*11, p=5.09x10(-6)). Amino acid positions may be more strongly associated than classical HLA associations; for example with anti-Jo-1 autoantibodies and position 74 of HLA-DRB1 (p=3.47x10(-64)) and position 9 of HLA-B (p=7.03x10(-11)). We report novel genetic associations with HLA-DQB1 anti-TIF1 autoantibodies and identify haplotypes that may differ between adult-onset and juvenile-onset patients with these autoantibodies. Conclusions: These findings provide new insights regarding the functional consequences of genetic polymorphisms within the MHC. As autoantibodies in IIM correlate with specific clinical features of disease, understanding genetic risk underlying development of autoantibody profiles has implications for future research

    New discrete and polymeric supramolecular architectures derived from dinuclear Co(II), Ni(II) and Cu(II) complexes of aryl-linked bis-beta-diketonato ligands and nitrogen bases: synthetic, structural and high pressure studies

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    New examples of nitrogen base adducts of dinuclear Co(II), Ni(II) and Cu(II) complexes of the doubly deprotonated forms of 1,3-aryl linked bis-β-diketones of type [RC([double bond, length as m-dash]O)CH2C([double bond, length as m-dash]O)C6H4C([double bond, length as m-dash]O)CH2C([double bond, length as m-dash]O)R] (L1H2) incorporating the mono- and difunctional amine bases pyridine (Py), 4-ethylpyridine (EtPy), piperidine (pipi), 1,4-piperazine (pip), N-methylmorpholine (mmorph), 1,4-dimethylpiperazine (dmpip) and N,N,N′,N′-tetramethylethylenediamine (tmen) have been synthesised by reaction of the previously reported [Cu2(L1)2]·2.5THF (R = Me), [Cu2(L1)2(THF)2] (R = t-Bu), [Ni2(L1)2(Py)4] (R = t-Bu) and [Co2(L1)2(Py)4] (R = t-Bu) complexes with individual bases of the above type. Comparative X-ray structural studies involving all ten base adduct derivatives have been obtained and reveal a range of interesting discrete and polymeric molecular architectures. The respective products have the following stoichiometries: [Cu2(L1)2(Py)2]·Py (R = Me), [Cu2(L1)2(EtPy)2]·2EtPy (R = t-Bu), [Cu2(L1)2(pipi)2]·2pipi (R = t-Bu), [Cu2(L1)2(mmorph)2] (R = t-Bu), [Cu2(L1)2(tmen)2] (R = t-Bu) and {[Cu2(L1)2(pip)]·pip·2THF}n, [Co2(L1)2(tmen)2] (R = t-Bu), [Ni2(L1)2(Py)4]·dmpip (R = t-Bu), [Ni2(L1)2(pipi)4]·pipi (R = t-Bu) and [Ni2(L1)2(tmen)2] (R = t-Bu). The effect of pressure on the X-ray structure of [Cu2(L1)2(mmorph)2] has been investigated. An increase in pressure from ambient to 9.1 kbar resulted in modest changes to the unit cell parameters as well as a corresponding decrease of 6.7 percent in the unit cell volume. While a small ‘shearing’ motion occurs between adjacent molecular units throughout the lattice, no existing bonds are broken or new bonds formed
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