Test Application Time Minimization for RAS using Basis Optimization of Column Decoder

Random Access Scan, which addresses individual flip-flops in a design using a memory array like row and column decoder architecture, has recently attracted widespread attention, due to its potential for lower test application time, test data volume and test power dissipation when compared to traditional Serial Scan. This is because typically only a very limited number of random ``care'' bits in a test response need be modified to create the next test vector. Unlike traditional scan, most flip-flops need not be updated. Test application efficiency can be further improved by organizing the access by word instead of by bit. In this paper we present a new decoder structure that takes advantage of basis vectors and linear algebra to further significantly optimize test application in RAS by performing the write operations on multiple bits consecutively. Simulations performed on benchmark circuits show an average of 2-3 times speed up in test write time compared to conventional RAS.

First total synthesis of (±)-myltayl-4(12)-ene and single-crystal X-ray structure of exo-12-normyltaylan-4-yl 4-nitrobenzoate

The total synthesis of the unusual sesquiterpene (+/-)-myltayl-4(12)-ene 3 starting from the readily available cyclogeraniol 5 and the single-crystal X-ray structure of the 4-nitrobenzoate 12 of the noralcohol 11 are described.

Reproductive phenology of a tropical dry forest in Mudumalai, Southern India

1 Flowering and fruiting phenologies of a tropical dry forest in Mudumalai, southern India, were studied between April 1988 and August 1990. Two sites, a wetter site I receiving 1100mm and a drier site II receiving 600mm of rainfall annually, are compared. A total of 286 trees from 38 species at site I and 167 trees from 27 species at site II was marked for phenological observations. There were 11 species common to the two sites. Several hypotheses relating to the evolution of reproductive phenology are tested. 2 Frequency of species flowering attained a peak at site I during the dry season but at site II, where soil moisture may be limiting during the dry months, the peak was during the wet season. At both sites a majority of species flushed leaves and flowered simultaneously. Among various guilds, the bird-pollinated guild showed distinct dry season flowering, which may be related to better advertisement of large flowers to pollinators during the leafless dry phase. The wind-pollinated guild flowered mainly during the wet season, when wind speeds are highest and favourable for pollen transport. The insect-pollinated guild showed no seasonality in flowering in site I but a wet season flowering in site II. 3 Fruiting frequency attained a peak in site I during the late wet season extending into the early dry season; a time-lag correlation showed that fruiting followed rainfall with a lag of about two months. Site II showed a similar fruiting pattern but this was not statistically significant. The dispersal guilds (animal, wind, and explosive passively-dispersed) did not show any clear seasonality in fruiting, except for the animal-dispersed guild which showed wet season fruiting in site I. 4 Hurlbert's overlap index was also calculated in order to look at synchrony in flowering and fruiting irrespective of climatic (dry and wet month) seasonality. In general, overlap in flowering and fruiting guilds was high because of seasonal aggregation. Among the exceptions, at site II the wind-pollinated flowering guild did not show significant overlap between species although flowering aggregated in the wet season. This could be due to the need to avoid heterospecific pollen transfer. 5 Rarer species tended to flower earlier in the dry season and this again could be an adaptation to avoid the risk of heterospecific pollen transfer or competition for pollinators. The more abundant species flowered mainly during the wet season. Species which flower earlier have larger flowers and, having invested more energy in flowers, also have shorter flower to fruit durations.

Synthesis based on cyclohexadienes. Part 15. Total synthesis of (±)-prezizaene, (±)-prezizanol and (±)-jinkohol II

A new methodology for the synthesis of the complex ring system tricyclo[6.2.1.0(1.5)]undecane. present in the zizaene group of sesquiterpenes, is described. Acid-catalysed rearrangement of the endo alcohol 20 afforded the enone 12, which was transformed stereoselectively into the key intermediate. (+/-)-norprezizanone 10. The features of the synthesis are the transformation of a bicycle[2.2.2] octane framework into a bicycle[3.2.1] octane system by an acid-catalysed rearrangement and a stereoselective conjugate addition of a methyl group on an alpha,beta-unsaturated keto ester at -100 degrees C. Norprezizanone was converted into the sesquiterpenes (+/-)-prezizanol 5 and(+/-)-prezizaene 4. The first total synthesis of (+/-)-jinkohol II 6 is also presented.

Total synthesis of (±)-allo-cedrol [Khusiol]

The first total synthesis of (+/-)-allo cedrol 1 is described from the ketone 11 which involves the Lewis acid catalysed rearrangement of the prezizaene analogue 8 as the key step.

Total synthesis of the novel sesquiterpenes of Eremophila georgei Diels

The first stereoselective total synthesis of the natural sesquiterpenes 4 and 5, having the tricyclo[6.2.1.0(1,5)]undecane skeleton with a bridgehead methyl group, is reported via the intermediate 9, which was obtained by the acid catalysed rearrangement of the alcohols 7 and 8.

A methodology for spirocyclopentannulation. Stereoselective total synthesis of (+/-)-tochuinyl acetate and (+/-)-dihydrotochuinyl acetate

A methodology based on Claisen rearrangement and Wacker oxidation for the spirocyclopentannulation of ketones, and its application to a highly stereoselective first total synthesis of dihydrotoch

A simple strategy for spirocyclopentannullation of cyclic ketones. Formal total synthesis of (+/-)-acorone

A general and simple methodology for spirocyclopentannulation of cyclic ketones (or 4,4-disubstituted cyclopentenones from acyclic ketones) and its application in the synthesis of the spirodienone 7 via a prochiral precursor constituting a formal total synthesis of (+/-)-acorone (6), are described.

Chiral synthons from carvone .20. Stereo- and enantiospecific total synthesis of (-)-valeranone

Stereo- and enantiospecific total synthesis of the irregular sesquiterpene, valeranone, starting from S-6-methylcarvone employing a hydrindanone to decalone ring expansion methodology, is described.

Cyclopentaannulation of allyl alcohols via a radical cyclisation reaction. Total synthesis of 4-epibakkenolide-A

A four step cyclopentaannulation methodology starting from allyl alcohols using 5-exo-trig radical cyclisation as the key reaction, and its application to the total synthesis of 4-epibakkenolide is described.

Towards the total synthesis of tashironin related allo-cedrane natural products: further exploitation of the oxidative dearomatization-IMDA-RCM triad based strategy

Synthetic studies directed towards allo-cedrane based, tashironin sibling natural products, involving some deft functional group manipulations on a preformed tetracyclic scaffold, are delineated. (C) 2011 Elsevier Ltd. All rights reserved.

Stability of stochastic Leipholz column with stochastic loading

The Leipholz column which is having the Young modulus and mass per unit length as stochastic processes and also the distributed tangential follower load behaving stochastically is considered. The non self-adjoint differential equation and boundary conditions are considered to have random field coefficients. The standard perturbation method is employed. The non self-adjoint operators are used within the regularity domain. Full covariance structure of the free vibration eigenvalues and critical loads is derived in terms of second order properties of input random fields characterizing the system parameter fluctuations. The mean value of critical load is calculated using the averaged problem and the corresponding eigenvalue statistics are sought. Through the frequency equation a transformation is done to yield load parameter statistics. A numerical study incorporating commonly observed correlation models is reported which illustrates the full potentials of the derived expressions.

A total synthesis of 11-O-methyldebenzoyltashironin

A concise total synthesis of 11-O-methyldebenzoyltashironin is reported in which oxidative dearomatization-IMDA-RCM triad constitutes the key ring forming steps, while an unorthodox DIBAL-H mediated stereo- and regioselective reductive epoxide openings and implementation of the vinyl bromide-carbonyl equivalency concept were pivotal to the success of this endeavor. (C) 2011 Elsevier Ltd. All rights reserved.

ChemInform Abstract: Enantioselective Formal Total Synthesis of (-)-Homogynolide-A

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis Based on Cyclohexadienes. 5. A New Approach to the Synthesis of a-Ring Aromatic Steroids - a Formal Total Synthesis of (+/-)-Estrone

A new strategy for the construction of A-ring aromatic steroids which resulted in the formal total synthesis of estrone is described. Thus reaction of the adduct (9), obtained from 1-methoxy-4-methylcyclohexa-1,4-diene and acrolein, with 3-(m-methoxyphenyl)propylmagnesium bromide followed by oxidation afforded the bicyclo[2.2.2]octene derivative (14). Acid-catalysed rearrangement of (14) followed by an intramolecular Michael addition resulted in the cis tetraenone (18) which was dehydrogenated with palladium chloride to the pentaenone (22). Li/NH3 reduction of (22) gave 3-methoxy-D-homoestra-1,3,5(10)-trien-16-one (31) which has been converted into the methyl ether (37) of marrianolic acid, and its methyl ester (38).