Studies of Phosphazenes. Part 13.' Thermal Rearrangement Reactions of Some Met hoxycyclo phosp hazenes

The methoxycyclophosphazenes [NP(OMe),], (n = 3-6) rearrange on heating to give oxocyclophosphazanes, [N(Me)PO(OMe)],. Isomeric products are formed when n = 4-6. The lH, ,lP, and 13C n.m.r. data for the starting materials and the products are presented. The ethoxy- and n-propoxy-derivatives N,P,( OR)* do not undergo the above rearrangement. The geminal derivatives N,P,R,(OMe), (R = Ph or NHBut) on heating yield both fully and partially rearranged products, namely dioxophosphaz-1 -enes and oxophosphazadienes, as shown by 270- MHz lH n.m.r. spectroscopy. The non-geminal derivative N,P,( NMe,),(OMe), gives only the fully rearranged product N,Me,P,(NMe,),O,(OMe), whose structure has been established from its lH and 31P n.m.r. spectra.

Litteraturundervisning och ämnessyn i modersmål och litteratur: En kvalitativ undersökning bland 13 modersmålslärare inom den grundläggande utbildningen (åk 7–9)

I denna avhandling undersöker jag hur modersmålslärare inom den grundläggande utbildningen (åk 7–9) undervisar i litteratur. De frågor jag ställer mig är: Hur förverkligar lärarna sin litteraturundervisning i praktiken, hur förhåller de sig till den nya läroplanen i ämnet, Grunderna för läroplanen för den grundläggande utbildningen 2004, samt med vilken ämnes-, litteratur- och kunskapssyn utgår de från i sin undervisning? Undersökningsresultatet analyseras utifrån läroplan och utifrån en läsarorienterad, sociokulturell och funktionell litteratursyn och litteraturpedagogik. Undersökningen är kvalitativ och riktar sig i form av ett frågeformulär till alla modersmålslärare i högstadierna i huvudstadsregionen. Tretton lärare deltar slutligen och åtta av dessa svar uppföljs genom en tematisk intervju. Undersökningen sker våren 2005. Forskningsresultatet visar på att flera av lärarna till stor del bygger upp sin undervisning utifrån färdiga uppgifter och koncept och att undervisningen styrs av metoden, av frågan hur. Dessa lärares undervisning sker således inte utgående från en enhetlig ämnes-, litteratur- och kunskapssyn, utan ämnessynen varierar beroende på uppgift. Recensionen är den arbetsuppgift som är vanligast bland lärarna, även om flera lärare ställer sig tveksamma till den. Övriga uppgifter som förekommer bland flera lärare är uppgiftskoncept kring klassiker och litterära samtal inför klass. Tematisk litteraturundervisning används även av flera lärare, liksom Netlibris, som innebär att två klasser från olika skolor över nätet diskuterar en skönlitterär text. Både Netlibris och tematisk litteraturundervisning är metoder som lärarna förhåller sig positiva till och ser pedagogiska fördelar med. Den tematiska undervisningen sker emellertid ofta i form av koncept som återkommer i samma form år efter år. Två lärare strävar dock efter att arbeta utifrån en enhetlig ämnessyn – den erfarenhetspedagogiska. Dessa lärare använder sig av färre koncept i sin undervisning. De bygger snarare upp sin undervisning utifrån frågan varför än hur, vilket innebär att de i högre grad har möjlighet att beakta elevernas intressen och behov i utformandet av undervisningen. Detta syns bland annat i valet av böcker och teman. En av dessa lärare använder sig även av portfölj- och loggboksmetodik och låter, i enlighet med läroplanen, eleverna själva vara med och utvärdera undervisningen och den egna utvecklingen. Lärarna verkar överlag förhålla sig mera positiva till de uppgifter som bygger på dialog och som tar fasta på läsaren i läsprocessen. Trots att lärarna betonar dialogens betydelse i litteraturundervisningen, bygger undervisningen ändå ofta, och i flera fall helt och hållet, på uppgifter som saknar dialog. En av orsakerna till detta kan vara att gamla koncept, trots nya uppgifter, lever kvar i undervisningen. Att lärarna framhåller de uppgifter som utgår från läsning av gemensamma texter och som tar fasta på en läsarorienterad och sociokulturell litteratursyn, visar dock på att de nya uppgifterna håller på att omkullkasta de gamla; lärarnas litteraturundervisning befinner sig således i förändring. Samtliga lärare förhåller sig positiva till litteraturundervisning och framhåller att litteraturen sedan deras egen skoltid fått en mera framträdande roll i undervisningen. De påpekar också att modersmålsundervisningen idag är mindre färdighetsinriktad och går mot en ökad dialog.

Phase relations between Al2O3---Cr2O3 and FeAl2O4---FeCr2O4 solid solutions at 1823 K

Tie-lines between the corundum and spinel solid solutions have been determined experimentally at 1823 K. Next, activities of FeCr2O4 and FeAl2O4 in the spinel solid solution were determined by combining the tie-line data with literature values for the activities of Cr2O3 and Al2O3 in the corundum phase. Activities and the Gibbs energy of mixing for the spinel solid solution were also obtained from a model based on cation distribution between nonequivalent crystallographic sites in the oxide lattice. The difference between the Gibbs energy of mixing obtained experimentally and from the model has been attributed to a strain enthalpy term which is relatively unchanged in magnitude from the reported at 1373 K. The integral enthalpy of mixing obtained from experimental data at 1373 and 1823 K using the second law is compared with the model result.

Hydrogen- 1 and Carbon- 13 Magnetic Resonance Studies of Nonactin-Calcium Complex

For an understanding of the cation selectivity and general binding characteristics of macrotetralide antibiotic nonactin (NA) with ions of different sizes and charges, the nature of binding of divalent cation, Ca2+, to NA and conformation of the NA-Ca2+ complex have been studied by use of 270-MHz proton nuclear magnetic resonance ('H NMR) and carbon-13 nuclear magnetic resonance (13C NMR). The calcium ion induced significantly large changes in chemical shifts for H7, H2, H3, and H5 protons of NA and relatively small changes for H18 and H2' protons. Changes in I3C chemical shift were quite large for carbonyl carbon, C,; it is noteworthy that in the NA-K+ complex, H2 and H2' protons practically do not show any change during complexation and carbonyl carbon shows a much smaller chemical shift change.

Theoretical investigations of the two-bond proton-carbon-13 coupling constants. Angular variations of the couplings involving carboxyl carbon

A formulation has been developed using perturbation theory to evaluate the π-contribution to the nuclear spin coupling constants involving nuclei at least one of which is an unsaturated center. This fromulation accounts for the π-contribution in terms of the core polarization and one-center exchange at the π-center. The formulation developed together with the Dirac vector model and Penney-Dirac bond-order formalisms was employed to calculate the geminal (two-bond) proton coupling constants of carboxyl carbons in α-disubstituted acetic acids. The calculated coupling constants were found to have an orientational dependence. The results of the calculation are in good agreement with the experimental values.

Meta-analyses identify 13 loci associated with age at menopause and highlight DNA repair and immune pathways

To newly identify loci for age at natural menopause, we carried out a meta-analysis of 22 genome-wide association studies (GWAS) in 38,968 women of European descent, with replication in up to 14,435 women. In addition to four known loci, we identified 13 loci newly associated with age at natural menopause (at P < 5 x 10(-8)). Candidate genes located at these newly associated loci include genes implicated in DNA repair (EXO1, HELQ, UIMC1, FAM175A, FANCI, TLK1, POLG and PRIM1) and immune function (IL11, NLRP11 and PRRC2A (also known as BAT2)). Gene-set enrichment pathway analyses using the full GWAS data set identified exoDNase, NF-kappaB signaling and mitochondrial dysfunction as biological processes related to timing of menopause.

Aspects of tautomerism. 13. Alkaline hydrolysis of .gamma.-, .delta.-, and .epsilon.-keto esters and their desoxy analogs. Geometrical constraints on keto participation

The rates of alkaline hydrolysis of methyl &benzoylpropionate (I), methyl y-benzoylbutyrate (11) and methyll6-benzoylvalerate (In) decrease in the order I > I1 > III. Keto participation is the predominant pathway in the case of y-keto esters. Evidence has also been obtained for keto participation in the case of 6-keto esters, whereas no such evidence is available in the case of r-keto esters studied.

Meta-analysis identifies 13 new loci associated with waist-hip ratio and reveals sexual dimorphism in the genetic basis of fat distribution

Waist-hip ratio (WHR) is a measure of body fat distribution and a predictor of metabolic consequences independent of overall adiposity. WHR is heritable, but few genetic variants influencing this trait have been identified. We conducted a meta-analysis of 32 genome-wide association studies for WHR adjusted for body mass index (comprising up to 77,167 participants), following up 16 loci in an additional 29 studies (comprising up to 113,636 subjects). We identified 13 new loci in or near RSPO3, VEGFA, TBX15-WARS2, NFE2L3, GRB14, DNM3-PIGC, ITPR2-SSPN, LY86, HOXC13, ADAMTS9, ZNRF3-KREMEN1, NISCH-STAB1 and CPEB4 (P = 1.9 × 10−9 to P = 1.8 × 10−40) and the known signal at LYPLAL1. Seven of these loci exhibited marked sexual dimorphism, all with a stronger effect on WHR in women than men (P for sex difference = 1.9 × 10−3 to P = 1.2 × 10−13). These findings provide evidence for multiple loci that modulate body fat distribution independent of overall adiposity and reveal strong gene-by-sex interactions.

Applications of the Vilsmeier reaction. 13. Vilsmeier approach to polycyclic aromatic hydrocarbons

The Synthesis of three typical polycyclic hydrocarbons (PAH) has been described, wherein the Vilsmeier reaction plays a major role. Vilsmeier reaction of the tetraloll gives the dihydronaphthaldehyde 2 which on cyclodehydration gives the dihydroarene 3. Ita dehydrogenation affords 3-methoxybenz[a]anthracene (4). Vilsmeier reaction on the dimethoxydihydronaphthalene 5 gives the versatile dimethoxydihydronaphthaldehyde 6 which has been converted to the dimethoxybenzo[c]fluorene 7 by direct cyclodehydration and the fulvene 10 by cyclodehydration of allylic alcohol 8 derived from 6 followed by dehydrogenation. The saturated alcohol 12 corresponding to 8 undergoes cyclodehydration to give the dimethoxyhexahydrobenzo[c]phenanthrene (13). Some of the advantages of the Vilsmeier approach to PAH have been pointed out.

Structure of pentacyclo[7.4.2.02,6.06,15.011,14]pentadec-4-ene-7,13-dione, a novel pentacyclic C15 quinane system

C 15H 1602 (a synthetic precursor to dodecahedrane), monoclinic, P21/n, a = 12.171 (5), b = 6.976(5), c = 13.868 (3) A, B = 102.56 (3) ° , Z = 4, D m = 1.30, D c = 1.318 g cm -3, F(000) = 488, g(Mo K¢t) = 0.92 cm- 1. Intensity data were collected on a Nonius CAD-4 diffractometer and the structure was solved by direct methods. Full-matrix least-squares refinement gave R = 0.077 (R w = 0.076) for 1337 observed reflections. All the five-membered rings are cis fused and have envelope (C s symmetry) conformations.

Presence of Lipids in Mycobacteriophage 13

The presence of lipids has been demonstrated in mycobacteriophage 13. The total lipid was composed of 69% phospholipids and 31% neutral lipids. More than two-thirds of phospholipids present in the phage were synthesized in the host prior to infection. The fatty acid composition of the phage differed markedly from that of its host, both in chain length and the degree of saturation. The phage lipid was mostly composed of saturated fatty acids of which more than 50% were short chain fatty acids. Changes in growth temperatures reflected variations in fatty acid composition, characteristic of the phage, and which were distinctly different from those of the host. Electron microscopic observations revealed that the phage has a membranous bilayer structure. The presence of lipids may facilitate the phage-host interaction especially in lipid-rich organisms like mycobacteria.