The efficient syntheses of the ABCD ring system of the originally proposed structure of azaspiracid-1 and the ABCDE ring system of the revised structure of azaspiracid-1 containing the correct stereochemistry at C₆, C₁₀, ...

A palladium-catalyzed (3 + 2) cycloaddition of a vinylcyclopropane and a ?-nitrostyrene is employed to rapidly assemble the cyclopentane core of the Melodinus alkaloids. The ABCD ring system of the natural product family is prepared in six steps from commercially available materials. PMID:21786746

Because of their varied physiological activity, steroids are important testing grounds on which to explore the utility of novel synthetic methodology. In this study cobalt, in the form of CpCo(CO)/sub 2/ is used as a matrix around which to assemble natural and unnatural polycyclic products, including the steroid nucleus. In this way, the total synthesis of A-ring aromatic ...

springer.comABCD Biometric Knowledge SAVE 20% Biometric Systems Technology, Design and Performance with an overview of the principles and methods needed to build reliable biometric systems. It covers three main topics: key biometric technologies, testing and management issues, and the legal and system

Complex ABCD field transformations are investigated for inhomogeneous optical ring cavities with losses and gain. It is shown that the sets of eigenfunctions, corresponding to counterpropagating waves, are really biorthogonal: the functions in each of these sets are really orthogonal relative to one another, and have a complex weighting factor independent ...

The study is the result of a comprehensive review of the Existing Transportation Systems and Community Facilities of the ABCD (Andrew-Buchanan-Clinton-DeKalb) Region. The transportation inventory consists of a description, with detailed maps, of the exist...

If the propagation of a light field can be satisfactorily described by a diffraction integral with an ABCD kernel, the propagation of its irradiance centroid is completely determined by the corresponding ABCD ray-transfer matrix in exactly the same way as if the centroid path were a conventional geometrical ray. However, potentially significant deviations ...

... Abstract : This report describes how optical system defects (tilt/jitter, decenter, and despace), propagate through an arbitrary paraxial optical system ...

A 14-membered macrocycle with an allene and a furan strategically located at across the ring from each other is synthesized using an allene ring closing metathesis reaction. Upon treatment of the macrocycle with a catalytic amount of Pd(OAc)₂ and other additives, the first transannular [4+3] cycloaddition occurred to yield 37% of a ...

The appropriateness of use and accuracy of age, blood pressure, clinical features and duration of symptoms (ABCD) scoring by non-stroke specialists while risk-stratifying patients with suspected transient ischaemic attack (TIA) are unknown. We reviewed all available ABCD data from referrals to a specialist neurovascular clinic. ABCD ...

Full details of the initial development and continued examination of a powerful intramolecular palladium(0)-mediated indole annulation for macrocyclization closure of the strained 16-membered biaryl ring system found in complestatin (1, chloropeptin II) and the definition of factors impacting its intrinsic atropodiastereoselectivity are described. Its ...

We generalize the transfer matrix ABCD theorem for paraxial rays of the optical system to skew rays propagated off axis, whether or not the system possesses rotational symmetry. Furthermore, we apply the generalized ABCD theorem to evaluate the diffraction integral matrix elements A-D expressed in terms of the ...

It is shown that every ray transfer matrix, often called the ABCD matrix, can be written as a similarity transformation of one of the Wigner matrices that dictate the internal space-time symmetries of relativistic particles, while the transformation matrix is a rotation preceded by a squeeze. The implementation of this mathematical procedure is described, and how it ...

The propagation of an elliptical Gaussian beam (EGB) through an astigmatic ABCD optical system in a turbulent atmosphere is investigated. An analytical formula for the average intensity of an EGB and a generalized tensor ABCD law for the generalized complex curvature tensor are derived. As an application example, we derived an ...

We cloned the entire bphABCD genes encoding degradation of biphenyl and polychlorinated biphenyls to benzoate and chlorobenzoates from the chromosomal DNA of Pseudomonas putida KF715. The nucleotide sequence revealed two open reading frames corresponding to the bphC gene encoding 2,3-dihydroxybiphenyl dioxygenase and the bphD gene encoding ...

The authors cloned the entire bphABCD genes encoding degradation of biphenyl and polychlorinated biphenyls to benzoate and chlorobenzoates from the chromosomal DNA of Pseudomonas putida KF715. The nucleotide sequence revealed two open reading frames corresponding to the bphC gene encoding 2,3-dihydroxybiphenyl dioxygenase and the bphD gene encoding ...

� Production Spread & Yield Irradiation Tests � Single ABCD or ABC/CAFE-pairs � Performance Analog & Digital Characterization � Threshold Scans.. � Laser, Source � Testbeam (non-irrad. & irrad. modules) ABC/CAFE-P & ABCD for burn-in testing of 8 modules #12;December January February March April May June July ABC submission CAFE

A time-dependent wave-packet approach is presented for the quantum dynamics study of the AB+CDE reaction system for zero total angular momentum. A seven-degree-of-freedom calculation is employed to study the chemical reaction of H2+C2H yields H + C2H2 by ...

Evolution of a convergent synthetic strategy to access (+)-spongistatin 2 (2), a potent cytotoxic marine macrolide, is described. Highlights of the synthesis include: development of a multicomponent dithiane-mediated linchpin union tactic, devised and implemented specifically for construction of the spongistatin AB and CD spiro ring systems; application of ...

A general approach to the regio- and stereoselective total synthesis of the benanomicin-pradimicin antibiotics (BpAs) is described. Construction of the aglycon has been achieved by 1) the diastereoselective ring-opening of a biaryl lactone by using (R)-valinol as a chiral nucleophile and 2) the stereocontrolled semi-pinacol cyclization of the aldehyde acetal by using SmI(2) in ...

Background and PurposeTransient ischemic attacks (TIAs) are a frequent diagnosis in the emergency department setting, yet expert opinion as to the proper follow up and need for hospitalization differs widely. Recently, an effort has been made to risk stratify patients presenting with TIAs through scoring systems such as the ABCD and ...

The calculation for the spectrum of beams passing through a multi-apertured ABCD optical system has not been finished in any personal computer when the aperture number is more than a certain value. By means of the expansion of the window function of the hard-edge aperture into a finite sum of complex Gaussian functions, an approximate analytical expression ...

A warning massage is printed if the system is a mixed continuous and discrete system. Example octave:1> sys=tf2sys([1 2],[3 4 5]); octave:2> [a,b,c,d] ...

... The ability of an inorganic cyclic system to ... the ring on ring-ring or ring-polymer interconversions will ... Polymers formed from these ring systems are of ...

Peroxisomes are involved in a variety of metabolic processes, including ?-oxidation of fatty acids, especially very long chain fatty acids. Three peroxisomal ABC proteins belonging to subfamily D have been identified in mammalian peroxisomes that have an important role in fatty acid metabolism. ABCD1/ALDP and ABCD2/ALDRP are suggested to be involved in the ...

The Wigner distribution function (WDF) is used to study the propagation of partially coherent beams through optical systems. The width and divergence of multimode beams are defined in terms of moments of the WDF. It is shown that these and other parameters of partially coherent beams of arbitrary form may be calculated using geometrical ray traces. Generalized transformation ...

SummarySynthesis of phenanthro[1,2-b]furan-10,11-dione, the core nucleus present in Tanshinone-I is described in 8�10 steps starting from 2-bromo-3,4-dihydro-1-naphthaldehyde. The bromoaldehyde was converted to methyl 2-(2-bromo-1-naphthyl)acetate or 2-(2-bromo-1-naphthyl)acetonitrile following the protocol of functional group transformations. Subsequent Suzuki coupling of this ester/nitrile ...

The asymmetric unit of the title compound, C₃₀H₄₆O₄�0.5CHCl₃, consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS)-7-(2-carboxy�ethyl)-3,4b,7,10b,12a-penta�methyl-8-(prop-1-en-2-yl)-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexa�deca�hydro�chrysene-3-carboxylic acid] ...

The asymmetric unit of the title compound, C(30)H(46)O(4)�0.5CHCl(3), consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS)-7-(2-carboxy-ethyl)-3,4b,7,10b,12a-penta-methyl-8-(prop-1-en-2-yl)-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexa-deca-hydro-chrysene-3-carboxylic acid] mol-ecule and one half-mol-ecule of chloro-form solvent, which is disordered about a twofold ...

Braided Rings. Saturn's narrow F ring, just outside the main ring system, is a very complex structure. In this close-up view it is made up of two narrow bright rings ...

The Automated Baseline Change Detection (ABCD) project is supported by the DOE Morgantown Energy Technology Center (METC) as part of its ER&WM cross-cutting technology program in robotics. Phase 1 of the Automated Baseline Change Detection project is summarized in this topical report. The primary objective of this project is to apply robotic and optical sensor technology ...

Immigration is a process fraught with both challenges and opportunities for families. In particular, East Indian families with U.S.-born adolescents experience the challenges of bridging cultures across generational divides; they are perceived by others as confused, identity less, and conflicted or as American-Born, Confused Desis (ABCDs). This article explores the history of ...

Purpose: The "advanced loans" module of the relatively new library software, ABCD, is an addition to the normal loans module and it offers a "generic transaction decision-making engine" functionality. The module requires extra installation effort and parameterisation, so this article aims to explain to the many potentially interested libraries, especially from the target-group ...

Three syntheses of the architecturally complex, cytotoxic marine macrolide (+)-spongistatin 1 (1) are reported. Highlights of the first-generation synthesis include: use of a dithiane multicomponent linchpin coupling tactic for construction of the AB and CD spiroketals, and their union via a highly selective Evans boron-mediated aldol reaction en route to an ABCD aldehyde; ...

The page in NASA's Planetary Rings Node presents images and animations of the rings system around Jupiter. There are also links to other sources of information on these rings.

The primary objective of this project is to apply robotic and optical sensor technology to the operational inspection of mixed toxic and radioactive waste stored in barrels, using Automated Baseline Change Detection (ABCD), based on image subtraction. Absolute change detection is based on detecting any visible physical changes, regardless of cause, between a current inspection ...

Rings in Shadow. This image of Saturn was taken while the spacecraft was departing the Saturnian system. The planet's disk casts a shadow across the ring ...

An effective synthesis of [?[CH₂NH]Tpg⁴]vancomycin aglycon (5) is detailed in which the residue 4 amide carbonyl of vancomycin aglycon has been replaced with a methylene. This removal of a single atom was conducted to enhance binding to D-Ala-D-Lac countering resistance endowed to bacteria that remodel their D-Ala-D-Ala peptidoglycan cell wall ...

Most quantum mechanical studies of triterpene synthesis have been done on small models. We calculated mPW1PW91/6-311+G(2d,p)//B3LYP/6-31G* energies for many C30H51O+ intermediates to establish the first comprehensive energy profiles for the cationic cyclization of oxidosqualene to lanosterol, lupeol, and hopen-3beta-ol. Differences among these 3 profiles were attributed to ...

The change of coherence and polarization of an electromagnetic beam modulated by a random anisotropic phase screen passing through any optical system is found within the framework of complex ABCD-matrix theory This means that the formalism can treat imaging and Fourier transform and free-space optical systems, as well as fractional ...

The design and implementation of a web-based diagnostic support tool for melanoma dermatological images and related diagnostic data is presented. The proposed system is semantic web-based and is driven by exploiting the combination of AJAX framework and topic map technology. A novel client/server architecture was developed that enables several clients to interact online with ...

Aug 19, 2008 ... Saturn's rings cast threadlike shadows on the planet's northern hemisphere. Note the translucent C ring, and thin outermost F ring. ...

PIA01487: Uranus' Far-flung Rings Uranus' rings, photographed by NASA's Voyager 2 in 1986 as it approached the plane of the Uranian ring system. Target Name: U Rings Is a...

Rotating ring and ring-disk electrodes were modeled. The primary, secondary, and below-the-limiting current distributions for ring electrodes were computed. The ring-disk system was modeled for secondary and below-the-limiting current distributions. Mass ...

This patent describes a system for minimizing thermal deformation of a steam turbine blade ring comprising: an upstream stationary blade ring separately supported to the inner casing; a downstream stationary blade ring, fit with the upstream stationary blade ring to maintain a relative position ...