1,762,920 research outputs found
Metal-free photoredox-catalysed formal C–H/C–H coupling of arenes enabled by interrupted Pummerer activation
No full textAryl–aryl cross-coupling constitutes one of the most widely used procedures for the synthesis of high-value materials that range from pharmaceuticals to organic electronics and conducting polymers. The assembly of (hetero)biaryl scaffolds generally requires multiple steps; coupling partners must be functionalized before the key bond-forming event is considered. The development of selective C–H arylation processes in arenes—which sidestep the need for prefunctionalized partners—is thus crucial for streamlining the construction of these key architectures. Here we report an expedient, one-pot assembly of (hetero)biaryl motifs using photocatalysis and two non-prefunctionalized arene partners. The approach is underpinned by the functionalization of a C–H bond in an arene coupling partner using the interrupted Pummerer reaction. A unique pairing of the organic photoredox catalyst and the intermediate dibenzothiophenium salts enables highly selective reduction in the presence of sensitive functionalities. The utility of the metal-free, one-pot strategy is exemplified by the synthesis of a bioactive natural product and the modification of complex molecules of societal importance.</p
Cloning, purification and characterisation of human and mouse ADAM 8 sheddase activity
Get PDFAl-Riyami H. Cloning, purification and characterisation of human and mouse ADAM 8 sheddase activity. Bielefeld (Germany): Bielefeld University; 2006
sj-docx-1-pps-10.1177_17456916221113759 – Supplemental material for C-H-E-A-T: Wordle Cheating Is Related to Religiosity and Cultural Tightness
No full textSupplemental material, sj-docx-1-pps-10.1177_17456916221113759 for C-H-E-A-T: Wordle Cheating Is Related to Religiosity and Cultural Tightness by Alexandra S. Wormley and Adam B. Cohen in Perspectives on Psychological Science</p
Analysis of the fitness landscape for the class of combinatorial optimisation problems
No full textAnatomy of the fitness landscape for a group of well known combinatorial optimisation problems is studied in this research and the similarities and the differences between their landscapes are pointed out. In this research we target the analysis of the fitness landscape for MAX-SAT, Graph-Colouring, Travelling Salesman and Quadratic Assignment problems. Belonging to the class of NP-Hard problems, all these problems become exponentially harder as the problem size grows. We study a group of properties of the fitness landscape for these problems and show what properties are shared by different problems and what properties are different. The properties we investigate here include the time it takes for a local search algorithm to find a local optimum, the number of local and global optima, distance between local and global optima, expected cost of found optima, probability of reaching a global optimum and the cost of the best configuration in the search space. The relationship between these properties and the system size and other parameters of the problems are studied, and it is shown how these properties are shared or differ in different problems. We also study the long-range correlation within the search space, including the expected cost in the Hamming sphere around the local and global optima, the basin of attraction of the local and global optima and the probability of finding a local optimum as a function of its cost. We believe these information provide good insight for algorithm designers
How Might Adam Smith Pay Professors Today?
Get PDFAdam Smith’s proposal for paying professors was intended to induce increased faculty knowledge. If students have imperfect information about what they learn, and universities can only imperfectly measure the input of faculty time in student learning, publications may be used to measure faculty knowledge. If professors’ ability to publish is positively related to their ability to produce student learning, which universities can imperfectly measure, publications may be necessary to attract more able professors. Since research signals faculty knowledge, schools that do not value publications per se could require higher publication standards and pay higher wages than schools that value only publications.
Folliet Joseph — Adam et Eve. Humanisme et sexualité
No full textH. J. Folliet Joseph — Adam et Eve. Humanisme et sexualité. In: Population, 21ᵉ année, n°4, 1966. p. 802
Folliet Joseph — Adam et Eve. Humanisme et sexualité
No full textH. J. Folliet Joseph — Adam et Eve. Humanisme et sexualité. In: Population, 21ᵉ année, n°4, 1966. p. 802
Pengetahuan, Sikap dan Perilaku Ibu Hamil terhadap Kehamilan Risiko Tinggi di Rsup. H. Adam Malik Medan
No full textABSTRAK
Tujuan : untuk mengetahui tingkat pengetahuan, sikap dan perilaku ibu hamil tentang kehamilan risiko tinggi.
Tempat : Penelitian dilakukan di poliklinik ibu hamil RSUP H. Adam Malik Medan, Rumkit Kesdam Putri Hijau Medan, dan RS Haji Mina Medan. Penelitian dimulai pada bulan Februari 2012 sampai dengan besar sampel terpenuhi.
Rancangan : “cross sectional” dengan suatu penelitian survey deskriptif .
Metode : Subyek penelitian adalah ibu hamil yang memeriksakan kehamilannya di poliklinik ibu hamil di RSUP H. Adam Malik Medan, Rumkit Kesdam Putri Hijau Medan, RS Haji Mina Medan dan memenuhi kriteria penelitian. Data penelitian dikumpulkan dengan menggunakan kuesioner yang didalamnya memuat beberapa kelompok pertanyaan mengenai : karakteristik responden, pengetahuan, sikap dan tindakan yang berhubungan dengan kehamilan risiko tinggi. Analisa data dilakukan dengan menggunakan program di komputer meliputi pemasukan data dan tabulasi data. Data yang dikumpulkan disajikan dalam bentuk tabel distribusi ferkuensi dan untuk menguji hipotesis digunakan uji chi-square.
Hasil : Dari hasil penelitian didapatkan 86 responden yang memenuhi kriteria penelitian dengan tingkat pengetahuan yang baik pada ibu hamil terhadap kehamilan resiko tinggi hanya dijumpai sebanyak 16 responden (18,6%) sedangkan dengan tingkat penegetahuan yang kurang mencapai 33 responden (38,4%). Sikap ibu hamil terhadap kehamilan resiko tinggi, yang bersikap kurang hanya 8,1 % sedangkan yang bersikap baik 44,2% dan cukup 47,7%. Perilaku ibu hamil terhadap kehamilan resiko tinggi dijumpai sebanyak 57 responden yang sudah mempunyai perilaku baik (66,3%).
Kesimpulan : berdasarkan analisa koefisien korelasi, terdapat hubungan yang bermakna antara pengetahuan dan sikap ibu hamil terhadap kehamilan resiko tinggi (p= 0,017) dan hubungan yang bermakna antara pengetahuan dan prilaku ibu hamil terhadap kehamilan resiko tinggi (p=0,022) serta hubungan yang bermakna antara sikap, prilaku ibu hamil terhadap kehamilan resiko tinggi (p=0,043).
Kata kunci : kehamilan resiko tinggi, pengetahuan, sikap, perilaku ibu hamil.55 HalamanTesis Magiste
ADAM SMITH'S VIEW OF HISTORY: CONSISTENT OR PARADOXICAL?
Get PDFThe conventional interpretation of Adam Smith is that he is a prophet of commercialism. The liberal capitalist reading of Smith is consistent with the view that history culminates in commercial society. The first part of the article develops this optimistic interpretation of Smith's view of history. Smith implies that commercial society is the end of history because 1) it supplies the ends of nature that he identifies; 2) it is inevitable; and 3) it is permanent. The second part of the article shows that Smith has some dark moments in his writings where he seems to reject completely such teleological notions. In this more civic humanist mood he confesses that commercial society does not supply the ends of nature, nor is it inevitable, nor is it permanent. Both views exist in Smith and the commentator is forced to choose between passages in Smith's work in order to support a particular interpretation of the former's view of history.Political Economy,
Development of and Mechanistic Insights into Palladium-Catalyzed C-H Arylation Reactions.
Get PDFBiaryls are important targets for numerous applications in organic synthesis. As a
result, the development of metal-mediated aryl cross-coupling has been extensively studied. The disadvantage of this approach is the requirement for each coupling partner to be prefunctionalized. To address this challenge, our studies focused on the development of direct, site selective C–H arylation.
We developed a PdII-catalyzed, ligand-directed C–H arylation reaction, that employs [Ar–IIII–Ar]+ reagents as terminal oxidants. High site-selectivity was achieved by employing substrates containing either oxygen or nitrogen-directing groups for functionalization of a specific C–H bond. This approach led to the installation of both electron rich and electron poor aryl groups. Additionally, excellent functional group tolerance was observed. Finally, investigations found that the generation of [Ar–IIII–Ar]+ in situ were feasible for subsequent C–H functionalization.
Mechanistic investigations of directed C–H arylation elucidated the catalytic cycle. This represents the first thorough investigation of a ligand-directed, palladium-catalyzed C–H arylation. These studies implicated a high-oxidation state dimeric palladium species as a catalytic intermediate. Furthermore, oxidation was found to be rate-limiting, unlike most C–H functionalization reactions.
We also extended this methodology to the C–H arylation of substrates lacking a directing group. We demonstrated that palladium catalysts and [Ar–IIII–Ar]+ oxidants afford site selective C2 arylation of indoles at room temperature, with excellent functional group tolerance. The installation of both electron rich and electron poor indoles, with electronically diverse of aryl groups was achieved. The viability of in situ oxidant generation, followed by indole arylation also was shown. Preliminary mechanistic investigations of indole arylation implicated the formation of an active catalyst prior to arylation.
This dissertation describes the development of site selective C–H arylation reactions using palladium catalysis. These transformations are general with respect to aryl group and substrate, and are complimentary to Pd0/II catalytic cycles. The functional group tolerance, broad substrate scope, and variety of installed aryl groups, make this methodology attractive for biaryl synthesis.PhDChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/75838/1/depreznr_1.pd
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