189 resultados para chains
Resumo:
The synthesis of thiophene-containing second (G2) and third generation (G3) dendronized macromonomers with methacrylate polymerizable units as well as their corresponding dendronized polymers is reported. The dendrons are prepared from branched thiophene oligomers and are decorated with straight alkyl chains for solubility reasons. The polymerization reactions were done with AIBN as initiator and the polymers were characterized by NMR spectroscopy, elemental analysis and GPC. Molar masses are in the range of 2.2-5.4 × 105 g mol-1 (G2) and 1.3-3.0 × 104 g mol-1 (G3) for different runs. These polymers are investigated by cyclic voltammetry and optical spectroscopy.
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A series of conjugated copolymers containing fluorene or indenofluorene units alternating with oligothiophene segments, with potential interest for use as the active layer in field-effect transistors, is investigated. Atomic force microscopy analysis of the morphology of thin deposits shows either the formation of fibrillar structures, which are the signature of long-range π stacking, or the presence of untextured aggregates, resulting from disordered assembly. These morphologies are interpreted in terms of the supramolecular organization of the conjugated chains. Molecular modeling simulations indicate that the commensurability between the lengths of the monomer units and the presence of alkyl side groups are the two key structural factors governing the chain organization into highly ordered assemblies. The most favorable structures are those combining fluorene (indenofluorene) units with unsubstituted bithiophene (terthiophene) segments.
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Supply chains are the core of most industrial networks in which your business operates. They provide the pipeline through which the products and services flow from supplier to customer across each element within the business activity system. Global supply chain relationships have become the basis for many industries with an international network of firms engaged in the supply of goods and services that must be produced to quality standards in one country and delivered just-in-time for assembly or integration into further production processes in another country, frequently many thousands of miles apart. This topic examines the nature of supply chain management and their role in strategic networking. The previous learning tasks have focused on having the correct internal mechanism to effectively manage the inputs and outputs of the organisation by implementing an effective and transparent management system. This learning task takes a look at how management intent strategy and innovation are used to measure the external factors that influence the overall performance of the organisation and develop new strategies by understanding the business cycle and the people within your market environment.
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The excellent multi-functional properties of carbon nanotube (CNT) and graphene have enabled them as appealing building blocks to construct 3D carbon-based nanomaterials or nanostructures. The recently reported graphene nanotube hybrid structure (GNHS) is one of the representatives of such nanostructures. This work investigated the relationships between the mechanical properties of the GNHS and its structure basing on large-scale molecular dynamics simulations. It is found that increasing the length of the constituent CNTs, the GNHS will have a higher Young’s modulus and yield strength. Whereas, no strong correlation is found between the number of graphene layers and Young’s modulus and yield strength, though more graphene layers intends to lead to a higher yield strain. In the meanwhile, the presences of multi-wall CNTs are found to greatly strengthen the hybrid structure. Generally, the hybrid structures exhibit a brittle behavior and the failure initiates from the connecting regions between CNT and graphene. More interestingly, affluent formations of monoatomic chains and rings are found at the fracture region. This study provides an in-depth understanding of the mechanical performance of the GNHSs while varying their structures, which will shed lights on the design and also the applications of the carbon-based nanostructures.
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The molecular structure of the copper–lead silicate mineral luddenite has been analysed using vibrational spectroscopy. The mineral is only one of many silicate minerals containing copper. The intense Raman band at 978 cm−1 is assigned to the ν1 (A1g) symmetric stretching vibration of Si5O14 units. Raman bands at 1122, 1148 and 1160 cm−1 are attributed to the ν3 SiO4 antisymmetric stretching vibrations. The bands in the 678–799 cm−1 are assigned to OSiO bending modes of the (SiO3)n chains. Raman bands at 3317 and 3329 cm−1 are attributed to water stretching bands. Bands at 3595 and 3629 cm−1 are associated with the stretching vibrations of hydroxyl units suggesting that hydroxyl units exist in the structure of luddenite.
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1,4-Diazabicyclo[2.2.2]octane (DABCO) forms well-defined co-crystals with 1,2-diiodotetrafluorobenzene (1,2-DITFB), [(1,2-DITFB)2DABCO], and 1,3,5-triiodotrifluorobenzene, [(1,3,5-TITFB)2DABCO]. Both systems exhibited lower-than-expected supramolecular connectivity, which inspired a search for polymorphs in alternative crystallization solvents. In dichloromethane solution, the Menshutkin reaction was found to occur, generating chloride anions and quaternary ammonium cations through the reaction between the solvent and DABCO. The controlled in situ production of chloride ions facilitated the crystallization of new halogen bonded networks, DABCO–CH2Cl[(1,2-DITFB)Cl] (zigzag X-bonded chains) and (DABCO–CH2Cl)3[(1,3,5-TITFB)2Cl3]·CHCl3 (2D pseudo-trigonal X-bonded nets displaying Borremean entanglement), propagating with charge-assisted C–I···Cl– halogen bonds. The method was found to be versatile, and substitution of DABCO with triethylamine (TEA) gave (TEA-CH2Cl)3[(1,2-DITFB)Cl3]·4(H2O) (mixed halogen bond hydrogen bond network with 2D supramolecular connectivity) and TEA-CH2Cl[(1,3,5-TITFB)Cl] (tightly packed planar trigonal nets). The co-crystals were typically produced in high yield and purity with relatively predictable supramolecular topology, particularly with respect to the connectivity of the iodobenzene molecules. The potential to use this synthetic methodology for crystal engineering of halogen bonded architectures is demonstrated and discussed.
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This Chapter considers a number of sector-specific access regimes that apply to infrastructure that exhibits natural monopoly characteristics. With the exception of Pt XIC of the CCA which regulates access to telecommunications infrastructure, they adopt the same form of negotiate-arbitrate model found in Pt IIIA of the CCA. In the event of a failure to negotiate commercial terms and conditions of access they allow the regulator to impose cost based (building block)tariffs. The regulator's decisions are subject to merits review and/or judicial review. The Chapter is divided into four Parts: • Part I considers access regulation in the electricity sector; • Part II considers access regulation in the gas sector; • Part III considers access regulation in the telecommunications sector; and • Part N considers access regulation in relation to port and rail bulk supply chains.
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In this paper new online adaptive hidden Markov model (HMM) state estimation schemes are developed, based on extended least squares (ELS) concepts and recursive prediction error (RPE) methods. The best of the new schemes exploit the idempotent nature of Markov chains and work with a least squares prediction error index, using a posterior estimates, more suited to Markov models then traditionally used in identification of linear systems.
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Australian labour law, at least from the mid-twentieth century, was dominated by the employment paradigm: the assumption that labour law’s scope was the regulation of employment relationships –full-time and part-time, and continuing, fixed term or casual – with a single (usually corporate) entity employer. But no sooner had the employment paradigm established and consolidated its shape, it began to fall apart. Since the 1980s there has been a significant growth of patterns of work that fall outside this paradigm, driven by organisational restructuring and management techniques such as labour hire, sub-contracting and franchising. Beyond Employment analyses the way in which Australian labour law is being reframed in this shift away from the pre-eminence of the employment paradigm. Its principal concern is with the legal construction and regulation of various forms of contracting, including labour hire arrangements, complex contractual chains and modern forms like franchising, and of casual employment. It outlines the current array of work relationships in Australia, and describes and analyses the way in which those outside continuous and fixed term employment are regulated. The book seeks to answer the central question: How does law (legal rules and principles) construct these work relationships, and how does it regulate these relationships? The book identifies the way in which current law draws the lines between the various work relationships through the use of contract and property ownership, and describes, analyses and synthesises the legal rules that govern these different forms of work relationships. The legal rules that govern work relationships are explored through the traditional lens of labour law’s protective function, principally in four themes: control of property, and the distribution of risks and rewards; maintenance of income security; access to collective voice mechanisms, focusing on collective bargaining; and health, safety and welfare. The book critically evaluates the gaps in the coverage and content of these rules and principles, and the implications of these gaps for workers. It also reflects upon the power relationships that underpin the work arrangements that are the focus of the book and that are enhanced through the laws of contract and property. Finally, it frames an agenda to address the gaps and identified weaknesses insofar as they affect the economic wellbeing, democratic voice, and health and safety of workers.
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The last two decades have witnessed a fragmentation of previously integrated systems of production and service delivery with the advent of boundary-less, networked and porous organisational forms. This trend has been associated with the growth of outsourcing and increased use of contingent workers. One consequence of these changes is the development of production/service delivery systems based on complex national and international networks of multi-tiered subcontracting increasingly labelled as supply chains. A growing body of research indicates that subcontracting and contingent work arrangements affect design and decision-making processes in ways that can seriously undermine occupational health and safety (OHS). Elaborate supply chains also present a regulatory challenge because legal responsibility for OHS is diffused amongst a wider array of parties, targeting key decision-makers is more difficult, and government agencies encounter greater logistical difficulties trying to safeguard contingent workers. In a number of industries these problems have prompted new forms of regulatory intervention, including mechanisms for sheeting legal responsibility to the top of supply chains, contractual tracking devices and increasing industry, union and community involvement in enforcement. After describing the problems just alluded to this paper examines recent efforts to regulate supply chains to safeguard OHS in the United Kingdom and Australia.
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Purpose – The purpose of this paper is to examine empirically, an industry development paradox, using embryonic literature in the area of strategic supply chain management, together with innovation management literature. This study seeks to understand how, forming strategic supply chain relationships, and developing strategic supply chain capability, influences beneficial supply chain outcomes expected from utilizing industry-led innovation, in the form of electronic business solutions using the internet, in the Australian beef industry. Findings should add valuable insights to both academics and practitioners in the fields of supply chain innovation management and strategic supply chain management, and expand knowledge to current literature. Design/methodology/approach – This is a quantitative study comparing innovative and non-innovative supply chain operatives in the Australian beef industry, through factor analysis and structural equation modeling using PAWS Statistical V18 and AMOS V18 to analyze survey data from 412 respondents from the Australian beef supply chain. Findings – Key findings are that both innovative and non-innovative supply chain operators attribute supply chain synchronization as only a minor indicator of strategic supply chain capability, contrary to the literature; and they also indicate strategic supply chain capability has a minor influence in achieving beneficial outcomes from utilizing industry-led innovation. These results suggest a lack of coordination between supply chain operatives in the industry. They also suggest a lack of understanding of the benefits of developing a strategic supply chain management competence, particularly in relation to innovation agendas, and provides valuable insights as to why an industry paradox exists in terms of the level of investment in industry-led innovation, vs the level of corresponding benefit achieved. Research limitations/implications – Results are not generalized due to the single agribusiness industry studied and the single research method employed. However, this provides opportunity for further agribusiness studies in this area and also studies using alternate methods, such as qualitative, in-depth analysis of these factors and their relationships, which may confirm results or produce different results. Further, this study empirically extends existing theoretical contributions and insights into the roles of strategic supply chain management and innovation management in improving supply chain and ultimately industry performance while providing practical insights to supply chain practitioners in this and other similar agribusiness industries. Practical implications – These findings confirm results from a 2007 research (Ketchen et al., 2007) which suggests supply chain practice and teachings need to take a strategic direction in the twenty-first century. To date, competence in supply chain management has built up from functional and process orientations rather than from a strategic perspective. This study confirms that there is a need for more generalists that can integrate with various disciplines, particularly those who can understand and implement strategic supply chain management. Social implications – Possible social implications accrue through the development of responsible government policy in terms of industry supply chains. Strategic supply chain management and supply chain innovation management have impacts to the social fabric of nations through the sustainability of their industries, especially agribusiness industries which deal with food safety and security. If supply chains are now the competitive weapon of nations then funding innovation and managing their supply chain competitiveness in global markets requires a strategic approach from everyone, not just the industry participants. Originality/value – This is original empirical research, seeking to add value to embryonic and important developing literature concerned with adopting a strategic approach to supply chain management. It also seeks to add to existing literature in the area of innovation management, particularly through greater understanding of the implications of nations developing industry-wide, industry-led innovation agendas, and their ramifications to industry supply chains.
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Glycerophospholipids (GPs) that differ in the relative position of the two fatty acyl chains on the glycerol backbone (i.e., sn-positional isomers) can have distinct physicochemical properties. The unambiguous assignment of acyl chain position to an individual GP represents a significant analytical challenge. Here we describe a workflow where phosphatidylcholines (PCs) are subjected to ESI for characterization by a combination of differential mobility spectrometry and MS (DMS-MS). When infused as a mixture, ions formed from silver adduction of each phospholipid isomer {e.g., [PC (16:0/18:1) + Ag]+ and [PC (18:1/16:0) + Ag]+} are transmitted through the DMS device at discrete compensation voltages. Varying their relative amounts allows facile and unambiguous assignment of the sn-positions of the fatty acyl chains for each isomer. Integration of the well-resolved ion populations provides a rapid method (< 3 min) for relative quantification of these lipid isomers. The DMS-MS results show excellent agreement with established, but time-consuming, enzymatic approaches and also provide superior accuracy to methods that rely on MS alone. The advantages of this DMS-MS method in identification and quantification of GP isomer populations is demonstrated by direct analysis of complex biological extracts without any prior fractionation.
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Breast cancer is the second most common cancer worldwide and the most common cancer reported in women. This malignant tumour is characterised by a number of specific features including uncontrolled cell proliferation. It ranks fifth in the world as a cause of cancer death in women. Early diagnosis increases 5 year survival rates up to 95%. Heparan sulfate proteoglycans (HSPGs) are complex proteins composed of a core protein to which a number of highly sulfated side chains are synthesised by a highly co-ordinated process resulting in distinct sulfation patterns, which determine specific interations with cell-signaling partners including growth factors, their receptors, ligands and morphogens. The enzymes responsible for chain initiation, elongation and sulfation are critical for creating HS chain variability conferring biological functionality. This study investigated single nucleotide polymorphism in SULF1, the enzyme responsible for the 6-0 desulfation of heparan sulfate side chains. We investigated this SNP in an Australian Caucasian case-control breast cancer population and found a significant association between SULF1 and breast cancer at both the allelic and genotypic level (allele, p=0.016; genotype, p=0.032). Our results suggest the res2623047 SNP in SULF1 may impact breast cancer susceptibility. Specifically, the T allele of rs2623047 in SULF1 is associated with a increased risk of developing breast cancer in our cohort. The identification of markers including SULF1 may improve detection of this disease at its earliest stages improving patient treatment and prognosis.
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This Article proposes a meta-regulation approach to address the gap between the objectives, commitment, practice and outcome in the accountability practice of the global supply chain in the developing countries. The literatures on the accountability practice in the global supply chains typically focuses on the strategies for raising corporate social accountability standards in multinational buying firms and seldom focuses on this strategies in the outsourced firms in the developing countries. This article tries to fill this void by examining the situation in Bangladesh, the third largest RMG supply country in the world. It conceptualizes a meta-regulation approach with the aim of raising social accountability practice in this industry. It shows that this regulation approach is suitable to effectively raise this practice standard in a perspective where the non-legal drivers are meagrely low, global buying firms are highly profit driven and the governmental agencies are either inadequate or highly corrupt.
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The structures of the 1:1 anhydrous salts of nicotine (NIC) with 3,5-dinitrosalicylic acid (DNSA) and 5-sulfosalicylic acid (5-SSA), namely (1R,2S)-1-methyl-2-(3-pyridyl)-1H-pyrrolidin-1-ium 2-carboxy-4,6-dinitrophenolate, C10H15N2+ C7H3N2O7-, (I) and (1R,2S)-1-methyl-2-(3-pyridyl)-1H-pyrrolidin-1-ium 3-carboxy-4-hydroxybenzenesulfonate, C10H15N2+ C7H5O6S-, (II) are reported. The asymmetric units of both (I) and (II) comprise two independent nicotinium cations (C and D) and either two DNSA or two 5-SSA anions (A and B), respectively. One of the DNSA anions shows a 25% rotational disorder in the benzene ring system. In the crystal of (I), inter-unit pyrrolidinium N-H...N(pyridine) hydrogen bonds generate zigzag NIC cation chains which extend along a while the DNSA anions are not involved in any formal inter-species hydrogen bonding but instead form pi--pi associated stacks which parallel the NIC chains along a [ring centroid separation, 3.857(2)A]. Weak C-H...O interactions between chain substructures give an overall three-dimensional structure. With (II), A and B anions form independent zigzag chains with C and D cations, respectively, through carboxylic acid O-H...N(pyridine) hydrogen bonds. These chains, which extend along b are pseudo-centrosymmetrically related and give pi--pi interactions between the benzene rings of anions A and B and the pyridine rings of the NIC cations C and D, respectively [ring centroid separations, 3.6422(19) and 3.7117(19)A]. Present also are weak intermolecular C-H...O hydrogen-bonding interactions between the chains, giving an overall three-dimensional structure.