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Covering: January to December 2009. Previous review: Nat. Prod. Rep., 2010, 27, 1186 [ABSTRACT FROM AUTHOR]

Covering: January to December 2008. Previous review: Nat. Prod. Rep., 2009, 26, 245 [ABSTRACT FROM AUTHOR]

Covering: 2007. Previous review: Nat. Prod. Rep., 2008, 25, 95 [ABSTRACT FROM AUTHOR]

A synthesis of the C1−C23 subunit of spirastrellolide B is described. The synthesis features two applications of a Kulinkovich-cyclopropanol ring-opening strategy for the coupling of esters with olefins to produce ketones. [ABSTRACT FROM AUTHOR]

The present study reports novel aspects of the reproductive biology of the male common ringtail possum (Pseudocheirus peregrinus). Plasma testosterone was measured through a stimulation test using the gonadotrophin-releasing hormone agonist, buserelin. Following intra-muscular administration of buserelin, there was an increase (P < 0.05) in testosterone concentration in the peripheral circulation 4 h later. Quantitative testicular histology of this species was described for the first time. Eight stages of the seminiferous epithelium cycle were identified in 10 possums and their relative frequency determined. Spermatozoa were recovered from the cauda epididymides of hemi-castrated possums and cryopreservation conducted in straws (6C min?1) using final glycerol concentrations ranging between 2 and 20% in Tris-citrate egg yolk extender (v/v). Frozen straws were thawed and post-thaw motility, rate of motility, the percentage of live?dead spermatozoa and the percentage of sperm with swollen decondensed nuclei recorded. Similar to other marsupial sperm, common ringtail possum cauda epididymidal spermatozoa required high levels of glycerol (10?16%) in order to maintain post-thaw viability. [ABSTRACT FROM AUTHOR]

Covering: January to December 2006. Previous review: Nat. Prod. Rep., 2007, 24, 87 [ABSTRACT FROM AUTHOR]

SUMMARY: BACKGROUND Sensitivity to erthanol''s locomotor activating and reinforcing effects may be influenced by some common neural mechanisms. Mice selectively bred in replicate for increased (FAST-1 and FAST-2) and decreased (SLOW-1 and SLOW-2) sensitivity to ethanol''s locomotor stimulant effects are useful for investigating the neural substrates of ethanol''s effects. Previous studies have suggested that differences in N-methyl-d-aspartate (NMDA) receptors may underlie differences in ethanol-induced locomotion in these mice. This study examined the responses of FAST and SLOW mice to ketamine, a fast-acting NMDA antagonist. In addition, reverse-selected lines (r-FAST-1, r-FAST-2, r-SLOW-1, and r-SLOW-2) were tested as a means of verifying correlations detected in the forward-selected lines. Two initial studies characterized ketamine-induced locomotion in DBA/2J (D2) mice, an inbred strain chosen for its high sensitivity to ethanol-induced locomotion.METHODS After a 2- to 3-day period of habituation to test procedures, mice were given intraperitoneal injections of ketamine alone (0, 5, 10, 20, 30, and 60 mg/kg) or in combination with 1 or 2 g/kg ethanol. Locomotor activity was measured for 20 to 30 min in automated activity monitors.RESULTS When administered alone, ketamine dose-dependently stimulated the locomotor activity of D2 mice and also reduced the amount of ethanol-induced stimulation. Ketamine stimulated locomotion more in FAST mice than in SLOW mice. Reverse selection abolished these differences, because r-FAST and r-SLOW mice did not differ in their responses to ketamine. Ketamine potentiated ethanol''s locomotor effects within FAST mice and potentiated ethanol''s locomotor depressant effect within one replicate of SLOW mice.CONCLUSIONS We propose that sensitivities to ethanol- and ketamine-induced locomotion are genetically correlated and that the combined effects of ethanol and ketamine in FAST mice reflect a leftward shift in ethanol''s biphasic dose-response curve. [ABSTRACT FROM AUTHOR]

BACKGROUNDDrugs of abuse may share some common mechanisms of action. We examined this idea by determining whether cross-sensitization would occur between the locomotor stimulant effects of ethanol (EtOH) and those of morphine and cocaine.METHODSGenetically heterogeneous adult female mice were repeatedly treated with 2.5 g/kg EtOH, then challenged 24 hr later with one of four doses of morphine or cocaine (0, 5, 10, or 20 mg/kg for both drugs). Under the reciprocal conditions, mice were repeatedly injected with cocaine or morphine (10 or 20 mg/kg), then challenged 24 hr later with 2.0 g/kg EtOH. In all cases, locomotor responses were compared to those of repeatedly saline-treated control groups.RESULTSBehavioral sensitization was seen to the stimulant effects of EtOH, and to the effects of the higher, 20 mg/kg dose of both morphine and cocaine. EtOH-sensitized mice did not show cross-sensitization to morphine or cocaine. However, both single and multiple morphine pre-exposures induced enhanced activation to an EtOH challenge. Mice repeatedly injected with 10 or 20 mg/kg cocaine also exhibited increased sensitivity to the stimulant effects of EtOH.CONCLUSIONSThere is some overlap in the neural mechanisms underlying behavioral sensitization to the locomotor stimulant effects of EtOH and those mediating sensitization to the locomotor stimulant effects of morphine and cocaine. Differences seen under reciprocal treatments may be associated with conditioning factors, or reflect differences in the neurobiological specificity of the effects of these drugs. [ABSTRACT FROM AUTHOR]

A modular, 13-step synthesis of the tetrahydropyran-containing annonaceous acetogenin pyranicin is reported. Key features are the use of an Achmatowicz oxidation−Kishi reduction sequence for the assembly of a pyranone from a furan and the application of Fu’s alkyl−alkyl Suzuki coupling for subunit union. [ABSTRACT FROM AUTHOR]

A strategy for ketone synthesis with cyclopropanols as intermediates and its application to ()-spirolaxine methyl ether is described. The synthesis also features an application of Fu's alkyl−alkyl Suzuki coupling. [ABSTRACT FROM AUTHOR]

We calculate the average of two characteristic polynomials for the real Ginibre ensemble of asymmetric random matrices, and its chiral counterpart. Considered as quadratic forms they determine a skew-symmetric kernel from which all complex eigenvalue correlations can be derived. Our results are obtained in a very simple fashion without going to an eigenvalue representation, and are completely new in the chiral case. They hold for Gaussian ensembles which are partly symmetric, with kernels given in terms of Hermite and Laguerre polynomials respectively, depending on an asymmetry parameter. This allows us to interpolate between the maximally asymmetric real Ginibre and the Gaussian orthogonal ensemble, as well as their chiral counterparts. [ABSTRACT FROM AUTHOR]

Background Work-related stress (WRS) is known to cause ill-health and decreased productivity. Work in the education sector is thought to be particularly stressful. Few studies have considered risk factors for WRS and health in head teachers. Aims To investigate health in head teachers in West Sussex. To determine personal risk factors most likely to predict cases of WRS and of poor health in head teachers. Methods A cross-sectional study, in a population of 290 head teachers and principals of colleges of further education, using a validated questionnaire, ‘a short stress evaluation tool’ (ASSET) and additional questions derived from earlier studies. Results were compared with the ASSET database ‘norm’ groups: a general population of workers (GPN) group and a group of managers and professionals (MPN). ‘Caseness’ was defined as respondents who felt work was ‘very or extremely stressful’. Results Head teachers had poor physical and mental health compared to the GPN group. Psychological well-being, particularly of females and primary head teachers was worse than a comparative group of managers and professionals. Teaching Conclusions Prevalence of self-reported stress in head teachers in West Sussex is high. Female head teachers had worse health outcomes. Our study identified possible personal risk factors predicting WRS and/or poor health in head teachers. [ABSTRACT FROM AUTHOR]

The Kishi reduction of a planar oxacarbenium was investigated theoretically. The high diastereoselectivity for hydride transfer to the oxacarbenium intermediate is attributed to the conformation of the transition state that places the allyl side chain in an equatorial position in the major transition state and axial position in the minor. The minor transition state is destabilized by a 1,3-diaxial strain between the attacking hydride and the synallyl side chain. [ABSTRACT FROM AUTHOR]

Covering: January to December 2005. Previous review: Nat. Prod. Rep., 2006, 23, 79 [ABSTRACT FROM AUTHOR]

This study documents the occurrence of an aggressive invasive earthworm species in undisturbed forest soils of the southern Appalachian Mountains of northern Georgia, USA. Earthworms were sorted from samples collected in pitfall traps that had been set in mature, mesic oak-hickory forests in remote, high elevation, locations across northern Georgia. Specimens were continuously collected in these traps over the course of the summer and autumn of 1993, and more than 600 earthworms were collected from 35 different trapping sites. There were at least 9 different earthworm taxa collected during the study including three species not native to North American soils (Amynthas agrestis, Octolasion tyrtaeum, and O. cyaneum). The majority of earthworms collected in the study were A. agrestis. Because large numbers of A. agrestis were trapped at a single site, we made measurements of individuals in an attempt to examine the reproductive status of A. agrestis at that site over time. Small numbers of A. agrestis were trapped in July and August, peak abundance occurred in September, and there was a decline in abundance through November to zero trapped in December. Sexually mature adults were first trapped in small numbers in late August, but made up 80% of the total population by mid September, and 100% of the population in October and November. [ABSTRACT FROM AUTHOR]

There has been long-standing interestin tuning the metal–insulator phase transition in vanadiumdioxide (VO2) via the addition of chemical dopants. However,the underlying mechanisms by which doping elements regulate the phasetransition in VO2are poorly understood. Taking advantageof aberration-corrected scanning transmission electron microscopy,we reveal the atomistic origins by which tungsten (W) dopants influencethe phase transition in single crystalline WxV1–xO2nanowires.Our atomically resolved strain maps clearly show the localized strainnormal to the (122̅) lattice planes of the low W-doped monoclinicstructure (insulator). These strain maps demonstrate how anisotropiclocalized stress created by dopants in the monoclinic structure acceleratesthe phase transition and lead to relaxation of structure in tetragonalform. In contrast, the strain distribution in the high W-doped VO2structure is relatively uniform as a result of transitionto tetragonal (metallic) phase. The directional strain gradients arefurthermore corroborated by density functional theory calculationsthat show the energetic consequences of distortions to the local structure.These findings pave the roadmap for lattice-stress engineering ofthe MIT behavior in strongly correlated materials for specific applicationssuch as ultrafast electronic switches and electro-optical sensors. [ABSTRACT FROM AUTHOR]

A total synthesis of largazole that proceeds in 8 steps from commercial materials is reported, along with some structure−activity relationships. A combination of NMR studies and molecular modeling have also provided a preliminary picture of the conformation of largazole. [ABSTRACT FROM AUTHOR]

We describe observations with the Mopra radiotelescope designed to assess the feasibility of the H2O Maser Southern Galactic Plane Survey. We mapped two one-square-degree regions along the Galactic plane using the new 12-mm receiver and the UNSW Mopra spectrometer. We covered the entire spectrum between 19.5 and 27.5 GHz using this setup with the main aim of finding out which spectral lines can be detected with a quick mapping survey. We report on detected emission from H2O masers, NH3 inversion transitions (1,1), (2,2) and (3,3), HC3N (3?2), as well as several radio recombination lines. [ABSTRACT FROM AUTHOR]

X-ray crystal structures of three salts of protonated triethylenetetramine, (H4TETA)4, with succinate, maleate, and fumarate anions are reported. Structures of the complexes (H4-triethylenetetramine)(hydrogenmaleate)4·2H2O (H4TETA)(Hmal)4·2H2O (1), (H4-triethylenetetramine)(hydrogenfumarate)4·3.3H2O (H4TETA)(Hfum)4·3.3H2O (2), and (H4-triethylenetetramine)(succinate)2(H4TETA)(suc)2(3) all form assemblies of alternating two-dimensional layers of (H4TETA)4and the anionic species via hydrogen-bond networks. Both classical and nonclassical hydrogen bonds between the protonated amine groups, anions, and water molecules were observed. X-ray powder diffraction measurements, differential thermal analysis/thermogravimetry, density vapor sorption, and Karl Fischer titration measurements were performed to obtain confirmatory information about the water content in the structures 1and 2and to examine polymorphism within the salts. The nonhydrated salt 3was determined to be the most favorable salt formulation for use in medicinal applications. [ABSTRACT FROM AUTHOR]

“Sterically geared” 9-(2,2,2-triphenylethylidene)fluorene (1) is of potential interest as a photoactive moiety in molecular devices, and the 2-tert-butyl derivative (6) has been synthesized to investigate photoisomerization. E and Z stereoisomers of 6 were separated and identified by X-ray crystallography. The tert-butyl group does not introduce additional strain, and its close proximity to the trityl group in the Z isomer suggests an attractive van der Waals interaction. The UV spectra of (E)-6 and (Z)-6 are nearly identical, showing absorption bands that are similar to those of fluorene occurring at wavelengths longer than 240 nm. Photoisomerization of 6 was investigated at 266, 280 and 320 nm. Solutions initially containing only (E)-6 or (Z)-6 were irradiated with pulsed laser light, monitoring isomerization by 1H NMR spectroscopy. Negligible photodecomposition was observed when the solutions were agitated by N2 ebullition. Experimental data were fitted to theoretical curves to obtain photoisomerization quantum yields (φZE and φEZ) ranging from 0.04 to 0.09. This first photoisomerization study of a dibenzofulvene reveals significant quantum yields, despite theoretical prediction of inefficient or negligible isomerization of the parent hydrocarbon, fulvene. Thermal isomerization of 6 at 270 °Mn(t1/2 = 120 min) was also followed by 1H NMR spectroscopy, resulting in an estimated activation energy (ΔG‡) of 43 kcal/mol. [ABSTRACT FROM AUTHOR]

BACKGROUND: Inhibin-B decreases and activin increases FSH secretion in adults. We investigated whether an FSHinhibin/activin feedback loop exists before or during puberty. METHODS: FSH secretion was stimulated with 10?g/kg leuprolide acetate (GnRH agonist) in 18 girls, ages 1.013.2 years, and 11 boys, ages 8.915.2 years, with variations in pubertal development, and in five normal 9- to 10-year-old girls. Blood, obtained at 0, 0.5, 1, 2, 4, 8, 12, 16, 20 and 24?h after GnRH agonist, was analysed for LH, FSH, activin-A, inhibin-A, inhibin-B, follistatin 288 and estradiol/testosterone. RESULTS: FSH increased within 30?min of GnRH agonist administration with a peak greater in girls than boys (P=0.0006). Baseline inhibin-B was greater in boys than girls (P=0.01), while baseline activin-A concentrations were greater in girls. GnRH agonist-stimulated FSH increased inhibin-B in girls by 8?h and in boys by 20?h (P<0.05), but did not affect activin-A. Inhibin-B increases were seen only in girls older than 5 years. CONCLUSIONS: An inhibin-BFSH feedback loop exists prior to the onset of puberty in girls older than 5 years. Sex differences in activin-A and inhibin-B concentrations may be responsible for sex differences in serum FSH concentrations. [ABSTRACT FROM AUTHOR]

BACKGROUND: FSH concentrations are higher in girls than in boys before puberty. We hypothesized that steroid‐mediated changes in FSH‐regulatory proteins underlie the sex differences in FSH secretion and pubertal timing. METHODS: FSH‐regulatory proteins, LH, FSH and sex steroids were measured in five boys, 10 girls, and five girls with Turner syndrome before and during sex steroid treatment (girls, 0.05 mg/day estradiol; boys, 5 mg/day testosterone) for up to 4 weeks. Blood was obtained every 15 min from 20.00 to 08.00 h before and during sex steroid treatment. RESULTS: The mean FSH concentration was higher in girls than in boys (P = 0.0044). Activin‐A concentrations were greater (P < 0.0001) and inhibin‐B concentrations lower (P < 0.0001) in girls compared with boys. Steroid treatment (i) suppressed LH/FSH concentrations in all subjects; (ii) increased the mean activin‐A concentration in all but the Turner girls (P = 0.001); and (iii) decreased inhibin‐B concentrations in boys (P = 0.005) but not in girls. Total follistatin and follistatin 288 concentrations did not differ by sex. CONCLUSIONS: Sex steroids regulate circulating activin‐A and inhibin‐B concentrations in children. The lower inhibin‐B and higher activin‐A concentrations may explain the higher FSH and earlier onset of puberty in girls. [ABSTRACT FROM AUTHOR]

SUMMARY: BACKGROUND Addictive drugs share the ability to induce euphoria, which may be associated with their potential for abuse. Replicate mouse lines with high (FAST-1, FAST-2) and low (SLOW-1, SLOW-2) sensitivity to ethanol-induced psychomotor stimulation (a possible animal model for the euphoria experienced by humans) have provided evidence for common genetic influences (pleiotropy) on sensitivity to the effects of ethanol and of GABA-A receptor acting compounds on locomotor activity. Differences between FAST and SLOW mice in locomotor response to certain other drugs were found later in selection. Reverse selection produced lines (r-FAST-1, r-FAST-2, r-SLOW-1, r-SLOW-2) with similar locomotor responses to ethanol. These lines are well suited for asking whether the same alleles that influence sensitivity to ethanol are also responsible for these later arising differences in drug sensitivity.METHODS Two replicate sets of forward- and reverse-selected FAST and SLOW lines were tested for the effects of multiple doses of morphine, cocaine, methamphetamine, nicotine, and scopolamine on their locomotor behavior. We predicted that differences in drug sensitivity between the FAST and SLOW lines would be reduced or eliminated in the reverse-selected lines.RESULTS Differences in sensitivity to morphine, cocaine, methamphetamine, and nicotine that arose in earlier generations of the FAST-1 and SLOW-1 lines ultimately also appeared in the FAST-2 and SLOW-2 lines. However, some differences between the FAST-2 and SLOW-2 lines (those in response to cocaine and methamphetamine) were not seen until several generations after selection had been relaxed. In lines reverse-selected for sensitivity to ethanol, differences in sensitivity to the other drugs were decreased, eliminated, or even reversed. No differences in scopolamine response were found in the replicate 1 forward- or reverse-selected lines. However, a small difference in scopolamine response in the replicate 2 lines was reversed.CONCLUSIONS Genes that influence the locomotor response to ethanol also influence locomotor response to other drugs with stimulant effects in the FAST and SLOW mice. The current data most strongly support this conclusion for sensitivity to morphine and nicotine. [ABSTRACT FROM AUTHOR]

Background. Working memory has been identified as a core cognitive deficit in schizophrenia that is associated with negative symptoms, but it is unclear whether it is impaired prior to onset of psychosis in symptomatic patients. Method. Thirty-eight young people at ultra high-risk (UHR) of developing psychosis (of whom nine later became psychotic) were compared with 49 healthy controls on tests of spatial working memory (SWM) and delayed matching-to-sample (DMTS). Results. Both SWM and DMTS performance was significantly poorer in the UHR groups. Those who later became psychotic generally performed more poorly than those who did not, although this did not reach significance for any measure. A significant association between SWM errors and negative symptoms was seen in the later-psychotic group only (P=0·02). Conclusions. Spatial working memory abilities are impaired in those at high-risk for psychosis. The relationship between working memory and negative symptoms may be useful as a predictive tool. [ABSTRACT FROM AUTHOR]

A theoretical and experimental study on atmospheric pressure microwave plasma-based assembly of free standing graphene sheets is presented. The synthesis method is based on introducing a carbon-containing precursor (C2H5OH) through a microwave (2.45 GHz) argon plasma environment, where decomposition of ethanol molecules takes place and carbon atoms and molecules are created and then converted into solid carbon nuclei in the ‘colder’ nucleation zones. A theoretical model previously developed has been further updated and refined to map the particle and thermal fluxes in the plasma reactor. Considering the nucleation process as a delicate interplay between thermodynamic and kinetic factors, the model is based on a set of non-linear differential equations describing plasma thermodynamics and chemical kinetics. The model predictions were validated by experimental results. Optical emission spectroscopy was applied to detect the plasma emission related to carbon species from the ‘hot’ plasma zone. Raman spectroscopy, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS) techniques have been applied to analyze the synthesized nanostructures. The microstructural features of the solid carbon nuclei collected from the colder zones of plasma reactor vary according to their location. A part of the solid carbon was deposited on the discharge tube wall. The solid assembled from the main stream, which was gradually withdrawn from the hot plasma region in the outlet plasma stream directed to a filter, was composed by ‘flowing’ graphene sheets. The influence of additional hydrogen, Ar flow rate and microwave power on the concentration of obtained stable species and carbon−dicarbon was evaluated. The ratio of sp3/sp2 carbons in graphene sheets is presented. A correlation between changes in C2 and C number densities and sp3/sp2 ratio was found. [ABSTRACT FROM AUTHOR]

We have conducted the first parallax and proper motion measurements of 6.7 GHz methanol maser emission using the Australian Long Baseline Array. The parallax of G 339.884–1.259 measured from five epochs of observations is 0.48 ± 0.08 mas, corresponding to a distance of kpc, placing it in the Scutum spiral arm. This is consistent (within the combined uncertainty) with the kinematic distance estimate for this source at 2.5 ± 0.5 kpc using the latest Solar and Galactic rotation parameters. We find from the Lyman continuum photon flux that the embedded core of the young star is of spectral type B1, demonstrating that luminous 6.7 GHz methanol masers can be associated with high-mass stars toward the lower end of the mass range. [ABSTRACT FROM AUTHOR]

In this report, we demonstrate band gap tuning of the active region emission wavelength from 365 nm to 250 nm in light emitting diodes fashioned from catalyst-free III-nitride nanowires. Optical characteristics of the nanowire heterostructures and fabricated devices are studied via electroluminescence (EL) and photoluminescence spectroscopy over a wide range of active region compositions. It is observed that for typical nanowire plasma assisted molecular beam epitaxy growth conditions, tuning of emission to wavelengths shorter than 300 nm is hampered by the presence of an optically active defect level. We show that by increasing the AlGaN nanowire growth temperatures this defect emission can be suppressed. These findings are applied to growth of the active region of a nanowire light emitting diode, resulting in a polarization-induced nanowire light emitting diode with peak EL at 250 nm. [ABSTRACT FROM AUTHOR]

Self-standing graphene sheets were synthesized using microwave plasmas driven by surface waves at 2.45 GHz stimulating frequency and atmospheric pressure. The method is based on injecting ethanol molecules through a microwave argon plasma environment, where decomposition of ethanol molecules takes place. The evolution of the ethanol decomposition was studied in situ by plasma emission spectroscopy. Free gas-phase carbon atoms created in the plasma diffuse into colder zones, both in radial and axial directions, and aggregate into solid carbon nuclei. The main part of the solid carbon is gradually withdrawn from the hot region of the plasma in the outlet plasma stream where nanostructures assemble and grow. Externally forced heating in the assembly zone of the plasma reactor has been applied to engineer the structural qualities of the assembled nanostructures. The synthesized graphene sheets have been analysed by Raman spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy and x-ray photoelectron spectroscopy. The presence of sp3 carbons is reduced by increasing the gas temperature in the assembly zone of the plasma reactor. As a general trend, the number of mono-layers decreases when the wall temperature increases from 60 to 100 °C. The synthesized graphene sheets are stable and highly ordered. [ABSTRACT FROM AUTHOR]