2,435 research outputs found
End-group functionalization of poly(2-oxazoline)s using methyl bromoacetate as initiator followed by direct amidation
Poly(2-alkyl/aryl-2-oxazoline)s (PAOx) are an alluring class of polymers for many applications due to the broad chemical diversity that is accessible for these polymers by simply changing the initiator, terminating agent and the monomer(s) used in their synthesis. Additional functionalities (that are not compatible with the cationic ring-opening polymerization) can be introduced to the polymers via orthogonal post-polymerization modifications. In this work, we expand this chemical diversity and demonstrate an easy and straightforward way to introduce a wide variety of functional end-groups to the PAOx, by making use of methyl bromoacetate (MeBrAc) as a functional initiator. A kinetic study for the polymerization of 2-ethyl-2-oxazoline (EtOx) in acetonitrile (CH3CN) at 140 degrees C revealed relatively slow initiation and slower polymerization than the commonly used initiator, methyl tosylate (MeOTs). Nonetheless, well-defined polymers could be obtained with MeBrAc as initiator, yielding polymers with near-quantitative methyl ester end-group functionality. Next, the post-polymerization modification of the methyl ester end-group with different amines was explored by introducing a range of functionalities, i.e. hydroxyl, amino, allyl and propargyl end-groups. The lower critical solution temperature (LCST) behavior of the resulting poly(2-ethyl-2-oxazoline)s was found to vary substantially in function of the end-group introduced, whereby the hydroxyl group resulted in a large reduction of the cloud point transition temperature of poly(2-ethyl-2-oxazoline), ascribed to hydrogen bonding with the polymer amide groups. In conclusion, this paper describes an easy and fast modular approach for the preparation of end-group functionalized PAOx
Hak Waris Anak Perempuan Tunggal Menurut Hukum Waris Adat Di Pulau Kisar Kabupaten Maluku Barat Daya
Women and men have the same position before the law regardless of gender, including the right to inherit. This research was carried out by referring to the type of normative legal research, or what is usually referred to as normative legal research or juridical where researchers will conduct a study of documents in the form of research conducted by examining literature sources and secondary data only, the type of research is descriptive analytical through an approach statutory and conceptual, guided by primary sources of legal material in the form of the 1945 Constitution of the Republic of Indonesia and the Civil Procedure Code as well as secondary and tertiary legal materials through the card system mechanism. Based on the research and presentation of the results and discussion, it was concluded that girls according to customary inheritance law on Kisar Island, especially in the community in Lebelau Village, North Kusar District, Southwest Maluku Regency, are not heirs, especially with regard to inheritance. This is influenced by the kinship system in adhered to by the people on Kisar Island in general, namely the patrilineal system so that sons become the heirs of priority according to customary law. The fulfillment of the inheritance rights of a daughter or only daughter in the family only includes inheritance that is the result of the income of the parents, where the fulfillment of these rights is very dependent on the wisdom of the parents
From Entity Description to Semantic Analysis: The Case of Theodor Fontane’s Notebooks
Within the last few decades, TEI has become a major instrument for philologists in the digital age, particularly since a set of mechanisms has recently been incorporated which facilitates the encoding of genetic editions. Editors use the XML syntax while aiming to preserve the quantity and quality of old books and manuscripts and publish many more of them online, mostly under free licenses. Scholars all over the world are now able to use huge datasets for further research. There are now many digital editions available, but only a few tools to analyze them. This article explores how web technologies (XML and related technologies as well as JavaScript) can be used to enrich the forthcoming edition of Theodor Fontane’s notebooks with data-driven visualizations of named entities and how at the same time applications can be built on these visualizations which are reusable for other edition projects in the TEI world. Because of the density and historical scope of references to named entities and the variety of entity types, Fontane’s notebooks lend themselves to advanced methods of semantic analysis
Cationic ring-opening polymerization of 2-propyl-2-oxazolines: understanding structural effects on polymerization behavior based on molecular modeling
Dual stack black blood carotid artery CMR at 3T: Application to wall thickness visualization
<p>Abstract</p> <p>Background</p> <p>The increasing understanding of atherosclerosis as an important risk factor for the development of acute ischemic events like ischemic stroke has stimulated increasing interest in non-invasive assessment of the structure, composition and burden of plaque depositions in the carotid artery wall. Vessel wall imaging by means of cardiovascular magnetic resonance (CMR) is conventionally done by 2D dual inversion recovery (DIR) techniques, which often fail in covering large volumes of interest as required in plaque burden assessment. Although the technique has been extended to 2D multislice imaging, its straight extension to 3D protocols is still limited by the prolonged acquisition times and incomplete blood suppression. A novel approach for rapid overview imaging of large sections of the carotid artery wall at isotropic spatial resolutions is presented, which omits excitation of the epiglottis. By the interleaved acquisition of two 3D stacks with the proposed motion sensitized segmented steady-state black-blood gradient echo technique (MSDS) the coverage of the carotid artery trees on both sides in reasonable scan times is enabled.</p> <p>Results</p> <p>10 patients were investigated with the proposed technique and compared to conventional transversal DIR turbo spin and gradient echo approaches centered at the height of the carotid bifurcation. In all MSDS experiments sufficient black-blood contrast could be obtained over the entire covered volumes. The contrast to noise ratio between vessel and suppressed blood was improved by 73% applying the motion sensitizing technique. In all patients the suspicious areas of vessel wall thickening could be clearly identified and validated by the conventional local imaging approach. The average assessable vessel wall segment length was evaluated to be 18 cm. While in 50% of the cases motion artifacts could be appreciated in the conventional images, none were detected for the MSDS technique.</p> <p>Conclusion</p> <p>The proposed technique enables the time efficient coverage of large areas of the carotid arteries without compromising wall-lumen CNR to get an overview about detrimental alterations of the vessel wall. Thickening of the vessel wall can be identified and the suspicious segments can be targeted for subsequent high-resolution CMR. The exclusion of the epiglottis may further facilitate reduction of swallowing induced motion artifacts.</p
Political Regimes and Sovereign Credit Risk in Europe, 1750-1913
This article uses a new panel data set to perform a statistical analysis of political regimes and sovereign credit risk in Europe from 1750 to 1913. Old Regime polities typically suffered from fiscal fragmentation and absolutist rule. By the start of World War I, however, many such countries had centralized institutions and limited government. Panel regressions indicate that centralized and?or limited regimes were associated with significant improvements in credit risk relative to fragmented and absolutist ones. Structural break tests also reveal close relationships between major turning points in yield series and political transformations
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