ABSTRACT The Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene yields a mixture of carbodiene Diels-Alder adducts. B3LYP/6-31G(d) simulations indicate that the conversion of addends into methyl (1R*,2S*,3S*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate occurs via two-stage heterodiene Diels-Alder reaction and (in a second ...

In the title compound, C(35)H(36)N(2)O(5)·0.5C(4)H(10)O, the asymmetric unit contains one bicyclo-[3.3.1]nonane mol-ecule and a half-occupancy diethyl ether solvent with the O atom lying on a crystallographic inversion center. Two intra-molecular N-H⋯O hydrogen bonds generate S(6) ring motifs. The bicyclo-[3.3.1]nonane ring system adopts a chair-boat conformation. In the crystal structure, the ...

In the context of the search for gasoline surrogates for kinetic modeling purpose, this paper describes a new model for the low-temperature auto-ignition of n-heptane/iso-octane/hexene/toluene blends for the different linear isomers of hexene. The model simulates satisfactory experimental results obtained in a rapid compression machine for temperatures ranging from 650 to 850 K in the case of b...

This paper introduces the oil and gas workplace context and describes work practices observed at a large Norwegian gas refinery. Ethnographic fieldwork was carried out over a ten day period, consisting of observational studies and informal interviews. They are a small, inter-disciplinary group who are highly mobile and work in a hazardous, critical environment where mistakes can pose risk to he...

The intramolecular [3+2] cycloaddition (32CA) of alkene-tethered α-silyloxydiazoalkanes provides variable stereoselectivity in generating bicyclic pyrazolines where the silyloxy group is either syn or anti to the newly formed pyrazoline ring. To elucidate the origin of the stereoselectivity, density functional theory (DFT) calculations were carried out for the energy of each transition state st...

317 The Rockefeller University Press $30.00 J. Cell Biol. Vol. 216 No. 2 317–330 https://doi.org/10.1083/jcb.201609124 Introduction MAPK pathways sense aspects of the extracellular environment and transmit this information to regulate various cellular processes. Most proteins involved in the MAPK pathways were identified in the 1970s and 1980s and then were characterized and linked together in ...

330 NATURE | VOL 398 | 25 MARCH 1999 | www.nature.com characters, which allow a greater range of excursion of the shoulder joint in the locomotion of multituberculates and living therians, have evolved at least twice among the Mesozoic mammals. Alternatively, the mobile joints between the clavicle, interclavicle and scapula could be ancestral conditions shared by J. jenkinsi and the more derive...

It is well established that hypoxia causes excess accumulation of glutamate in developing neural tissues. This study aimed to elucidate the mechanism by which glutamate can cause retinal ganglion cell (RGC) death through the N-methyl-D-aspartate (NMDA) receptors (NR) in the developing retina. One-day-old Wistar rats were exposed to hypoxia for 2 hours and then killed at different time points. N...

In the title compound, C31H30N2O, the cis-fused cyclo-hexene and cyclo-octane rings adopt boat and boat-chair conformations, respectively. The essentially planar five-membered N-heterocyclic ring [r.m.s. deviation = 0.017 (1) Å] is cis- and trans-fused, respectively, with the cyclo-hexene and cyclo-octane rings. In the crystal, mol-ecules are linked into inversion dimers through pairs of weak C...

Many 3-dimensional (3D) techniques have been utilized to register and analyze the face in 3 dimensions, but each system has its own merits and disadvantages. C3D is a relatively new 3D imaging system that was developed to capture the 3D geometry of the face. Landmark identification on 3D facial models is facilitated by a software-based facial analysis tool developed by the authors. The reproduc...