bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum Monte Carlo study of small pure and mixed spin-polarized tritium clusters
Authors: Bešlić I. , Vranješ Markić L. , Boronat J.
Published: February 2008

We have investigated the stability limits of small spin-polarized clusters consisting of up to ten spin-polarized tritium T↓ atoms and the mixtures of T↓ with spin-polarized deuterium D↓ and hydrogen H↓ atoms. All of our calculations have been performed using the variational and diffusion Monte Carlo methods. For clusters with D↓ atoms, the released node procedure is used in cases where the wave function has nodes. In addition to the energy, we have also calculated the structure of small clusters using unbiased estimators. Results obtained for pure T↓ clusters are in good accordance with previous calculations, confirming that the trimer is the smallest spin-polarized tritium cluster. Our results show that mixed T↓–H↓ clusters having up to ten atoms are unstable and that it takes at least three tritium atoms to bind one, two, or three D↓ atoms. Among all the considered clusters, we have found no other Borromean states except the ground state of the T↓ trimer.
The DΣ+1 state of Li7H: Comparison of observations with vibronic theory
Authors: Wu Chia-Ying , Luh Wei-Tzou , Xavier Gadea F. , Stwalley William C.
Published: February 2008

The excited DΣ+1 electronic state of Li7H has been observed up to near its dissociation limit by a pulsed optical-optical double resonance fluorescence depletion spectroscopic technique. An extensive vibronic calculation has been performed with a diabatic approach with purely potential couplings involving a set of eight diabatic states of Σ+1 symmetry, corresponding to seven neutral states and one ionic state. Twenty-six new vibrational levels have been observed. Both the derived vibrational energy spacings and the vibronic ones are similarly irregular. The observed spectral linewidths and vibronic resonance widths are found to vary similarly with increasing energy. Observed asymmetric spectral lineshapes may be attributed to the strong radial couplings between the discrete levels of the DΣ+1 electronic state and the continuum states of the CΣ+1 electronic state. The mutual agreement between the spectral results and the vibronic results demonstrates that the DΣ+1 electronic state of Li7H is better characterized by the vibronic approach.
ND-stretching vibrational energy relaxation of NH2D in liquid-to-supercritical ammonia studied by femtosecond midinfrared spectroscopy
Authors: Schäfer Tim , Schwarzer Dirk , Lindner Jörg , Vöhringer Peter
Published: February 2008

Femtosecond midinfrared pump-probe spectroscopy was carried out to explore the dynamics of vibrational energy relaxation of NH2D in fluid ammonia NH3. The ND-stretching fundamental of the partially deuterated solute NH2D was excited by femtosecond pulses centered at 2450cm−1, and both the ground-state bleach and the anharmonically shifted transient absorption of the same vibration was probed. The temperature of the sample was varied between 230 and 450K, while the pressure was tuned from 10to1500bar, thereby entering both the liquid and the supercritical phase of the fluid solution. The density and temperature dependence of the ND-stretching lifetime suggests that hydrogen bonding is of negligible importance for vibrational energy relaxation. Rather, the energy transfer dynamics can be understood qualitatively in terms of a simple Landau-Teller description for vibrational energy relaxation using molecular dynamics simulations to estimate the spectral density of the fluctuating forces exerted by a weakly interacting Lennard-Jones solvent (NH3) onto the vibrationally excited solute (NH2D).
Ordered phthalocyanine superstructures on Ag(110)
Authors: Palmgren P. , Angot T. , Nlebedim C. I. , Layet J.-M. , Le Lay G. , Göthelid M.
Published: February 2008

Organic-metal interfaces, in particular, self-assembling systems, are interesting in the field of molecular electronics. In this study, we have investigated the formation of the Ag(110)-iron phthalocyanine (FePc) interface in a coverage range of less than 1 and up to 2 ML using synchrotron based photoelectron spectroscopy and low energy electron diffraction. As-deposited FePc forms a densely packed first layer exhibiting a 3×2∕c(6×2) symmetry. Upon thermal treatment the order at the interface is modified depending on the initial FePc coverage, resulting in less densely packed but still ordered superstructures. The first monolayer is relatively strongly bound to the substrate, leading to the formation of an interface state just below the Fermi level. The highest occupied molecular orbital of FePc in the second layer is found at 1eV higher binding energy compared to the interface state.
Dependence of the conduction of a single biphenyl dithiol molecule on the dihedral angle between the phenyl rings and its application to a nanorectifier
Authors: Kondo Hisashi , Nara Jun , Kino Hiori , Ohno Takahisa
Published: February 2008

The transport properties of a biphenyl dithiol (BPD) molecule sandwiched between two gold electrodes are studied using the nonequilibrium Green’s function method based on the density functional theory. In particular, their dependence on the dihedral angle (φ=90°–180°) between two phenyl rings is investigated. While the dihedral-angle dependence of the density of states projected on the BPD molecular orbitals is small, the transport properties change dramatically with φ. The transmission at the Fermi energy exhibits a minimum at φ=90.0° and greatly increases with φ. The ratio of the maximum obtained at φ=180° to the minimum exceeds 100. As an application of this characteristic transport behavior, a BPD molecule functionalized with NH2 and NO2 groups is considered. It is found that this molecule works as a nanorectifier.
Influence of pressure on the slow and fast fractional relaxation dynamics in lysozyme: A simulation study
Authors: Calandrini Vania , Kneller Gerald R.
Published: February 2008

The article reports on a molecular dynamics simulation study of the influence of moderate, nondenaturing pressure on the slow and fast internal relaxation dynamics of lysozyme. The model parameters of the fractional Ornstein–Uhlenbeck process are used to quantify the changes. We find that the nonexponential character for diffusive motions on time scales above 10ps is enhanced and that the diffusion processes are slowed down. The diffusive motions on the subpicosecond time scale appear, in contrast, accelerated, whereas the nonexponential character is not altered by pressure. We attribute these findings to the different natures of slow and fast relaxation processes, which are characterized by structural rearrangements and collisions, respectively. The analyses are facilitated by the use of spatially resolved relaxation rate spectra.
Elastic/inelastic and charge transfer collisions of H++H2 at collision energies of 4.67, 6, 7.3, and 10eV
Authors: Amaran Saieswari , Kumar Sanjay
Published: February 2008

Quantum mechanical studies of vibrational and rotational state-resolved differential cross sections, integral cross sections, and transition probabilities for both the elastic/inelastic and charge transfer processes have been carried out at collision energies of 4.67, 6, 7.3, and 10eV using the vibrational close-coupling rotational infinite-order sudden approach. The dynamics has been performed employing our newly obtained quasidiabatic potential energy surfaces which were generated using ab initio procedures and Dunning’s correlation-consistent-polarized quadrupole zeta basis set. The present theoretical results for elastic/inelastic processes provide an overall excellent agreement with the available experimental data and they are also found to be almost similar to that obtained in earlier theoretical results using the ground electronic potential energy surface, lending credence to the accuracy and reliability of the quasidiabatic potential energy surfaces. The results for the complementary charge transfer processes are also presented at these energies.
High thermal stability of carbon-coated L10-FePt nanoparticles prepared by salt-matrix annealing
Authors: Rong Chuan-Bing , Poudyal Narayan , Chaubey Girija S. , Nandwana Vikas , Liu Yuzi , Wu Y. Q. , Kramer M. J. , Kozlov M. E. , Baughman R. H. , Liu J. Ping
Published: February 2008

Monodisperse L10-FePt nanoparticles with size ranging from 3to8nm were prepared by the salt-matrix annealing method. It was observed that the annealed particles have high thermal stability—no sintering occurred even when the particles were heated at 1100°C for an hour. This high thermal stability resulted from carbon coating of the particles during salt-matrix annealing as consequence of decomposition of surfactants.
Thickness dependent spin-injection effects in Nd0.7Ca0.3MnO3∕YBa2Cu3O7 bilayers
Authors: Hsu Daniel , Lin J. G. , Chang C. P. , Chen C. H. , Chiang C. H. , Chan W. C. , Wu W. F.
Published: February 2008

Two Nd0.7Ca0.3MnO3∕YBa2Cu3O7 (NCMO/YBCO) bilayers with different thickness ratios are fabricated and the spin-injection effects are investigated. The NCMO/YBCO samples have thicknesses of 100nm∕200nm and 200nm∕200nm, which are denoted as N/Y(1) and N/Y(2), respectively. It is shown that the current-induced suppression rate of superconducting transition temperature (dTc∕dI) in YBCO is enhanced by four to six times of magnitude in N/Y(1) and N/Y(2) compared with that in pure YBCO. Furthermore, dTc∕dI in N/Y(2) is larger than that in N/Y(1), which suggests that the thickness of NCMO has influence on the pair breaking in YBCO.
Observations of liquidlike order of charged rodlike lipid A diphosphate assemblies at pH 8.5
Authors: Faunce Chester A. , Paradies Henrich H.
Published: February 2008

A new structural form of charged lipid A diphosphate, with a molecular weight of 5.9×106Da and a rodlike shape (L=800nm), was found in aqueous solutions at pH 8.5. The experimental techniques used in the investigation were light scattering, small-angle x-ray scattering (SAXS), and electron microscopy. Measurements of the static-structure factor S(Q) as a function of the ionic strength are presented over the concentration regimes C>C* and C<C*, with C*=1particle∕length3. The position of the first maximum of the structure factor S(Q) was found to scale with C1∕3 below and with C1∕2 above, the critical concentration C* (2.5μg∕mL). SAXS results in the semidilute concentration range C⩾C* show that strong interparticle correlations exist even at concentrations as high as 15C*, in contrast with results for hard-rod systems. The magnitude of the correlations depends on both the lipid A diphosphate concentration at pH 8.5 and the Debye screening length k−1. For a constant lipid A diphosphate concentration at pH 8.5, as the amount of salt was increased a decrease in structure was observed. There was also a shift in the peak of the first maximum position Qmax to larger scattering wave vectors. The observed phase behavior (C=15C*) exhibited an isotropic I-Sm transition and an I-N-Sm transition, which were recorded on electron microscope images.
Weakening of magnetohydrodynamic interchange instabilities by Alfvén waves
Authors: Benilov E. S. , Hassam A. B.
Published: February 2008

Alfvén waves, made to propagate along an ambient magnetic field and polarized transverse to a gravitational field g, with wave amplitude stratified along g, are shown to reduce the growth rate of interchange instability by increasing the effective inertia by a factor of 1+(B¯y′∕B¯zkz)2, where B¯z is the ambient magnetic field, kz is the wavenumber, and B¯y′ is the wave amplitude shear. Appropriately placed Alfvén wave power could thus be used to enhance the stability of interchange and ballooning modes in tokamaks and other interchange-limited magnetically confined plasmas.
Immobilization of layered double hydroxides in the fluidic system for nanoextraction of specific DNA molecules
Authors: Chen Jem-Kun , Chan Chia-Hao , Chang Feng-Chih
Published: February 2008

The purpose of this study was to immobilize inorganic layered double hydroxides (LDHs) on the poly(methylmethacrylate) substrate as the media to extract the specific DNA molecules through fluidic system to enhance the efficiency of extract specific DNA molecules from extremely low concentration in sample solution. LDH immobilized through solvent swelling and plasma treatment on the polymer surface captured the specific DNA molecules lysed from Escherichia coli (E. coli) cells as the target DNA molecules with 2×10−4g∕l of concentration in sample solution mixed biomacromolecules lysed from human blood. The encapsulated DNA molecules released through dissolving of LDHs by slight acid (pH=4–5) solution then amplified by polymerase chain reaction (PCR) process through the primers for E. coli cells. The DNA molecules amplified by PCR process were characterized by gel electrophoresis to recognize the existence of E. coli cells. The results show that immobilized LDHs could be regarded as the specific DNA detector for rapid disease diagnosis through fluidic system.
Electromagnetic coupling of light into a silicon solar cell by nanodisk plasmons
Authors: Hägglund Carl , Zäch Michael , Petersson Göran , Kasemo Bengt
Published: February 2008

Photocurrents of silicon pn junctions patterned with arrays of elliptical Au nanodisks were experimentally and theoretically investigated near the particle plasmon resonance wavelengths, for varying light polarizations and angles of incidence. At plasmon resonance wavelengths, overall backscattering and dissipation were strongly enhanced compared to an unpatterned junction, resulting in lower photocurrents. In contrast, enhanced photocurrents were observed for wavelengths slightly off resonance. Measurements and finite element calculations show that the photocurrent changes occur via plasmon-induced far field effects, rather than by near field enhancement close to the particles. The far field effects are strongly dependent on the particle proximity and coupling to the Si substrate.
Dielectric relaxation in polyimide nanofoamed films with low dielectric constant
Authors: Zhang Yihe , Ke Shanming , Huang Haitao , Zhao Lihang , Yu Li , Chan H. L. W.
Published: February 2008

Polyimide nanofoamed films have been prepared from the polyimide precursors (PMDA-ODA) and poly(ethylene oxide) (PEO) in N,N-dimethylacetamide. The dielectric properties of the films were studied over the temperature range of −150–150°C and a frequency range of 1Hz–10MHz. The frequency dependence of the dielectric constant for nanofoamed films with different amounts of PEO was studied. An relaxation process at below the glass transition temperature of the polyimide nanofoamed films was found. The peak value of the dielectric loss increased with increasing amount of PEO.
Hybrid integration of GaAs quantum cascade lasers with Si substrates by thermocompression bonding
Authors: Andrijasevic D. , Austerer M. , Andrews A. M. , Klang P. , Schrenk W. , Strasser G.
Published: February 2008

A hybrid GaAs quantum cascade laser system obtained by Au–Au thermocompression bonding epilayer down onto gold coated silicon substrates is presented in this paper. The performance of the hybrid laser in low-duty-cycle pulsed operation in comparison to an unbonded one was not deteriorated. The lasers run with a threshold of 4.6kA∕cm2, emit around 12μm, and with a maximum optical output power of 550mW at cryogenic temperatures. The key advantage of such hybrid chips is the possibility of integrating III-V cascade lasers with established silicon photonics technology, such as silicon-on-insulator waveguides, V-groove fiber coupling and microfluidics.
Mechanical stress impact on thin Pd1−xFex film thermodynamic properties
Authors: Wagner Stefan , Pundt Astrid
Published: February 2008

Thermodynamic properties of thin films deviate strongly from those of bulk. The deviations are reported to originate from microstructure and from mechanical stress, whereas the contribution of both is unknown in particular. Focussing on the mechanical stress contribution and by using Pd1−xFex–H as a model system, it is shown that mechanical stress strongly changes phase transition pressures. The measured loading pressures shift up to 400mbars in contrast to 18mbars for bulk. These shifts relate to the film bonding to the substrate and can be affected by film detachment.
The effects of the ZnTe capping layer thickness on the optical and electronic properties in CdTe∕ZnTe quantum dots
Authors: Lee H. S. , Park H. L. , Kim T. W.
Published: February 2008

Photoluminescence spectra showed that the excitonic peak corresponding to the interband transitions from the ground electronic subband to the ground heavy-hole band (E1-HH1) in the CdTe∕ZnTe quantum dots (QDs) was shifted to a higher energy with increasing thickness of the ZnTe cap layer. The intensity of the excitonic peak related to the E1-HH1 transition for the CdTe∕ZnTe QDs increased with increasing thickness of the ZnTe cap layer. The activation energy of the electrons confined in the CdTe∕ZnTe QDs increased with increasing thickness of the ZnTe cap layer.
Large inverse magnetoresistance in fully epitaxial Fe∕Fe3O4∕MgO∕Co magnetic tunnel junctions
Authors: Greullet F. , Snoeck E. , Tiusan C. , Hehn M. , Lacour D. , Lenoble O. , Magen C. , Calmels L.
Published: February 2008

Fully epitaxial Fe(001)∕Fe3O4(001)∕MgO(001)∕Co micron-sized magnetic tunnel junctions have been elaborated on MgO(001) substrates. X-ray reflectivity and high-resolution transmission electron microscopy revealed a good quality and epitaxial growth of the stack with abrupt interfaces. The magnetotransport measurements exhibit a large negative tunneling magnetoresistance (TMR) value for magnetic tunnel junctions including an Fe3O4 layer and a MgO tunnel barrier (−8.5% at 300K and −22% at 80K). Moreover, the sign of the TMR changes with the applied bias. We discuss here the structural quality of the samples and the transport measurement results.
Constrained modeling of domain patterns in rhombohedral ferroelectrics
Authors: Shu Y. C. , Yen J. H. , Chen H. Z. , Li J. Y. , Li L. J.
Published: February 2008

A nonconventional phase-field model is developed to predict ferroelectric domain structures. It employs a set of field variables motivated by multirank laminates to represent energy-minimizing domain configurations, giving rise to an explicit expression of the energy-well structure. The framework is applied to domain simulation in the rhombohedral phase assuming that polarization is close to the ground states. An electromechanical self-accommodation pattern consisting of eight rhombohedral variants and an engineered domain configuration are predicted and found in good agreement with those observed in experiment.
Controlled synthesis of oriented single-crystal ZnO nanotube arrays on transparent conductive substrates
Authors: She Guang-Wei , Zhang Xiao-Hong , Shi Wen-Sheng , Fan Xia , Chang Jack C. , Lee Chun-Sing , Lee Shuit-Tong , Liu Chang-Hong
Published: February 2008

Large-scale arrays of highly oriented single-crystal ZnO nanotubes (ZNTs) are successfully fabricated on transparent conductive substrates by a simple method from an aqueous solution at a low temperature (typically 85°C). The tubular morphology of the ZnO nanostructures is formed by a defect-selective chemical etching of the electrodeposited ZnO nanorods. The size of the ZNT arrays is determined by that of ZnO nanorod arrays which can be readily controlled by tuning several electrodeposition parameters. The present method can be employed to prepare ZNT arrays on flexible, conductive substrates, as well as on patterned conductive substrates.
Effect of nanodot areal density and period on thermal conductivity in SiGe∕Si nanodot superlattices
Authors: Lee Minjoo Larry , Venkatasubramanian Rama
Published: February 2008

We report on the effect of nanodot (ND) areal density and period on cross-plane thermal conductivity κ⊥ in SiGe∕Si nanodot superlattices (NDSLs). For all ND areal densities considered, we found that κ⊥ in SiGe∕Si NDSLs decreased monotonically with decreasing period and reached values lower than those in typical SiGe alloys (∼6.5Wm−1K−1). At short periods, κ⊥ was as low as 2.0–2.7Wm−1K−1 and at a fixed period, increasing the ND areal density led to lower κ⊥. This work indicates that low κ⊥ can be attained in SiGe∕Si NDSLs either with a low SL period, a high ND areal density, or both.
Land use effects on soil quality indicators in north-eastern Iran
Authors: Golchin A. , Asgari H.
Published: February 2008

Forest and grassland soils in north-eastern Iran are being degraded and destroyed by inappropriate agricultural activities. This study investigated effects of land-use changes on several indicators of soil quality (SQ) in this area. We found higher organic carbon (OC) and total nitrogen (N) contents in virgin soils (under forests and pastures) than in cultivated soils. Distribution of OC throughout the soil profile was influenced by the type and length of tillage operations performed at different sites. Cultivation reduced OC content of the subsoil (0.50–1.00 m) and contributed to a more uniform distribution of organic matter in the plough layer (0–0.50 m) by mixing upper and lower horizon soils and incorporating of organic inputs to a greater depth. In 4 of 5 sites, tilled soils had lower ECe and SAR values than the virgin soils, but when the water table was near the soil surface, the ECe and SAR values were higher in cultivated sites. This suggests that when the water table is deep, the quality of salt-affected virgin soils may be improved by cultivation and leaching of excess salts to deeper layers. In 4 of 5 sites, the virgin soils had slightly greater clay content than the tilled soils, but these soils also had 41–89% less dispersible clay than their cultivated counterparts. The virgin soils had 2–31-fold greater aggregate stability, 4–33% lower bulk density, 6–31% higher water-holding capacity (at 0.3 bar suction), higher cation exchange capacity (CEC), and higher respiration rate than the cultivated soils. The results of this study indicate that frequent tillage and use of summer fallow deteriorates SQ by decreasing SOC and enhancing soil erosion through decreased structural stability and increased mechanically dispersible clay. The results stress the need for farming practices that preserve OC in soils in order to reduce flooding and erosion risks.
Links between dryland salinity, mosquito vectors, and Ross River Virus disease in southern inland Queensland—an example and potential implications
Authors: Biggs A. J. W. , Mottram P.
Published: February 2008

The impacts of dryland salinity on landscapes and agriculture are well documented, but few links have been made to public health. A cluster of cases of Ross River Virus (RRV) disease in the vicinity of a dryland salinity expression in the town of Warwick, Queensland, has highlighted the potential role of secondary salinity expressions as breeding zones for mosquitoes, including vector species of RRV. It is suggested that further work is required to investigate the matter in Queensland, particularly in relation to the expansion of urban populations in south-east Queensland into old agricultural lands containing secondary salinity expressions.
Distribution of fractions of zinc and their contribution towards availability and plant uptake of zinc under long-term maize (Zea mays L.) - wheat (Triticum aestivum L.) cropping on an Inceptisol
Authors: Behera Sanjib Kumar , Singh Dhyan , Dwivedi B. S. , Singh Sarjeet , Kumar K. , Rana D. S.
Published: February 2008

Intensive farming with high yielding cultivars, application of high analysis NPK fertilisers, and reduced use of organic manures caused a decrease in the availability of zinc (Zn) in Indian soils. We collected soil and plant samples from an ongoing long-term experiment at Indian Agricultural Research Institute, New Delhi, to study the distribution of different fractions of Zn in an Inceptisol and their contribution towards the Zn availability in soil and Zn uptake in maize–wheat crop rotation. The treatments used for the study were NPK, NPK + FYM, NPK + Zn, and control (no fertiliser or manure). The DTPA-Zn concentration in soil was higher where Zn had been applied and declined with an increase in soil depth. The distribution of different fractions of Zn under various treatments and depths was inconsistent, and varied in a cropping year. The average concentration of total Zn (mg/kg) was 183, 183, 171, and 211 in 0–0.15, 0.15–0.30, 0.30–0.45, and 0.45–0.60 m depth, respectively. Residual Zn was the dominant portion of total Zn at all soil depths. Grain and stover yield of maize ranged from 1.10 to 2.43 t/ha and 1.22 to 2.46 t/ha, respectively, under different treatments, whereas, the yield of wheat grain varied from 2.25 to 4.69 t/ha and that of wheat straw from 2.56 to 5.20 t/ha. Highest uptake of Zn by both the crops occurred in Zn-treated plots. Zinc associated with easily reducible manganese, carbonate and iron and aluminum oxides contributed directly towards DTPA-extractable Zn. Sorbed Zn (SORB-Zn) and Zn associated with organic matter (OM-Zn) contributed significantly towards Zn uptake by the 2 crops.
Long-term acidification of a Brazilian Acrisol as affected by no till cropping systems and nitrogen fertiliser
Authors: Vieira F. C. B. , Bayer C. , Mielniczuk J. , Zanatta J. , Bissani C. A.
Published: February 2008

Cropping systems and N fertilisation affect soil acidification mainly due to the removal of alkaline plant material from the field and nitrate leaching. The study evaluated the acidification of a subtropical soil under no till cropping systems with different C and N addition rates for 19 years. The contributions of leguminous and non-leguminous crops (fallow/maize, black oat/maize, black oat + vetch/maize, black oat + vetch/maize + cowpea, lablab + maize, pigeon pea + maize, and digitaria) and mineral N fertiliser (0 and 180 kg N/ha.year as urea) to total acidification were estimated. Cropping systems and N fertilisation significantly affected soil pH, which ranged from 4.3 to 5.1. The presence of leguminous species and mineral N promoted greater decreases in soil pH and net soil acidification, which resulted in increases in exchangeable Al content and Al saturation. Black oat + vetch/maize with N fertilisation promoted the highest soil net acidification rate (2.65 kmol H+/ha.year), while digitaria had the lowest (1.07 kmol H+/ha.year). Leguminous species and N fertilisation increased soil acidification through changes in the C cycle associated with the removal of alkaline plant material by grains. Leguminous-based cropping systems promoted higher maize yields than those comprising essentially gramineous species, indicating an opportunity for a reduction in N fertiliser rates. With N application, however, maize yield did not differ among cropping systems, despite differences in soil pH and exchangeable Al.
Milk composition and growth in the southern brown bandicoot, Isoodon obesulus (Marsupialia:Peramelidae)
Authors: Duffy Deidre J. , Rose Randy
Published: February 2008

Milk and growth data from six litters of southern brown bandicoots (Isoodon obesulus) from south-eastern Tasmania were analysed. Five of these were born in the wild and one was born in captivity. The quantitative changes in milk composition were examined for total protein, carbohydrates (hexose and lactose), lipid, dissolved solids, and estimated energy content. During ‘early-phase’ lactation (before Day 30) protein levels were 10.5 g (100 mL)–1, hexose 0.34 g (100 mL)–1, lipids 10.4 g (100 mL)–1, and solids 27.3 g (100 mL)–1. ‘Mid-phase’ milk (Days 31–45) showed an increase in all constituents: protein 13.8 g (100 mL)–1, hexose 1.66 g (100 mL)–1, lipid 12.2 g (100 mL)–1, and solids 41.4 g (100 mL)–1. Protein and hexose levels decreased in ‘late-phase’ milk (Day 46–60) to 11.3 g (100 mL)–1, and 1.58 g (100 mL)–1, respectively, and the amount of lipids and dissolved solids increased to 26.4 g (100 mL)–1, and 52.3 g (100 mL)–1, respectively. There was no evidence of lactose in milk from the latter half (final 28 days) of lactation. Total milk energy increased from 6.0kJmL–1 in early-phase milk, to 8.9 kJ mL–1 in mid-phase, and 12.0 kJ ml–1 in late-phase. Changes in body mass, head, tail, and pes lengths were examined for 16 pouch young. Instantaneous relative growth rates were calculated for the final 42 days of lactation, revealing a decrease in overall growth rates from 14.0% increase in bodyweight per day in early-phase, to 7.8% daily during mid-phase, and 3.5% daily increase during late-phase lactation. Analysis of the relationship between milk and growth in I. obesulus demonstrates that morphological and developmental changes, especially the development of endothermy and time of first pouch exit, directly correlate with changes in growth rates, milk energy, and milk composition.
A
Drosophila
model for
LRRK2
-linked parkinsonism
Authors: Liu Zhaohui , Wang Xiaoyue , Yu Yi , Li Xueping , Wang Tao , Jiang Haibing , Ren Qiuting , Jiao Yuchen , Sawa Akira , Moran Timothy , Ross Christopher A. , Montell Craig , Smith Wanli W.
Published: February 2008

Mutations in the leucine-rich repeat kinase (
LRRK2
) gene cause late-onset autosomal dominant Parkinson's disease (PD) with pleiomorphic pathology. Previously, we and others found that expression of mutant LRRK2 causes neuronal degeneration in cell culture. Here we used the
GAL4
/
UAS
system to generate transgenic
Drosophila
expressing either wild-type human LRRK2 or LRRK2-G2019S, the most common mutation associated with PD. Expression of either wild-type human LRRK2 or LRRK2-G2019S in the photoreceptor cells caused retinal degeneration. Expression of LRRK2 or LRRK2-G2019S in neurons produced adult-onset selective loss of dopaminergic neurons, locomotor dysfunction, and early mortality. Expression of mutant G2019S-LRRK2 caused a more severe parkinsonism-like phenotype than expression of equivalent levels of wild-type LRRK2. Treatment with
l
-DOPA improved mutant LRRK2-induced locomotor impairment but did not prevent the loss of tyrosine hydroxylase-positive neurons. To our knowledge, this is the first
in vivo
“gain-of-function” model which recapitulates several key features of LRRK2-linked human parkinsonism. These flies may provide a useful model for studying LRRK2-linked pathogenesis and for future therapeutic screens for PD intervention.
WIP is essential for lytic granule polarization and NK cell cytotoxicity
Authors: Krzewski Konrad , Chen Xi , Strominger Jack L.
Published: February 2008

Natural killer (NK) cells play important roles in host immunity by killing virus-infected and tumor cells. Killing of the target cell is achieved by formation of an immune synapse and localized secretion of lytic granules containing perforin and granzymes. Here, we demonstrate that Wiskott–Aldrich syndrome protein (WASp)-interacting protein (WIP), important in generation of a large complex of proteins involved in actin cytoskeleton rearrangements, is indispensable for NK cell cytotoxicity. WIP knockdown completely inhibited cytotoxicity, whereas overexpression of WIP enhanced NK cell cytolytic ability. WIP was found to colocalize with lytic granules. WIP segregated to the lysosomal fraction, where granzyme B activity was also found, and the interaction between WIP and granules was independent of WASp. Importantly, WIP knockdown inhibited polarization of lytic granules to the immune synapse, but not conjugate formation. These results indicate that WIP is involved in lytic granule transport and is essential for regulation of NK cell cytotoxic function.
Cell growth, global phosphotyrosine elevation, and c-Met phosphorylation through Src family kinases in colorectal cancer cells
Authors: Emaduddin Muhammad , Bicknell David C. , Bodmer Walter F. , Feller Stephan M.
Published: February 2008

The heterogeneity of cancer cell signaling is a significant obstacle for the effective development and clinical use of molecularly targeted therapies. As a contribution to a better understanding of the diversity of signaling activities in colorectal cancers (CRCs), we have analyzed the activity of Src family kinases (SFKs), which are implicated in human cancer development, in 64 CRC cell lines. A striking diversity of SFK activity was observed within this panel. Importantly, all CRC lines tested depend on SFK activity for their growth. In addition, SFK activity levels strongly correlated with global levels of tyrosine-phosphorylated (pTyr) proteins in CRC lines. SFK inhibition substantially reduced these pTyr levels, suggesting that SFKs may function as signal integration points and master controllers for the pTyr protein status in CRC lines. The majority of analyzed CRC lines with high-SFK activity express activated c-Met (pYpY1234/1235), a receptor tyrosine kinase contributing to the regulation of cell proliferation, migration, and invasion. Inhibition of SFKs reduced c-Met phosphorylation in most cases, indicating a reversed signal flow from SFK to c-Met. We conclude that SFK activity is important for the growth of CRC lines, although only low activity levels are required. If this also is true for CRC patients, tumors with low-SFK activity may be particularly sensitive to SFK inhibitors, and such patients should be targeted in clinical trials testing SFK inhibitors.
The same mutation in Gsα and transducin α reveals behavioral differences between these highly homologous G protein α-subunits
Authors: Zurita Adolfo R. , Birnbaumer Lutz
Published: February 2008

Mutating Arg-238 to Glu (R238E) in the switch 3 region of a transducin α (*Tα) in which 27 aa of the GTPase domain have been replaced with those of the α-subunit of the inhibitory G protein 1 (Gi1α), was reported to create an α-subunit that is resistant to activation by GTPγS, is devoid of resident nucleotide, and has dominant negative (DN) properties. In an attempt to create a DN stimultory G protein α (Gsα) with a single mutation we created Gsα–R265E, equivalent to *Tα–R238E. Gsα–R265E has facilitated activation by GTPγS, a slightly facilitated activation by GTP but much reduced receptor plus GTP stimulated activation, and an apparently unaltered ability to interact with receptor as seen in ligand binding studies. Further, the activity profile of Gsα–R265E is that of an α-subunit with unaltered or increased GTPase activity. The only change in Gsα that is similar to that in *Tα is that the apparent affinity for guanine nucleotides is decreased in both proteins. The molecular basis of the changed properties are discussed based on the known crystal structure of Gsα and the changes introduced by the same mutation in a *Tα (Gtα*) with only 23 aa from Gi1α. Gtα*–R238E, with four fewer mutations in switch 3, was reported to show no evidence of DN properties, is activated by GTPγS, and has reduced GTPase activity. The data highlight a critical role for the switch 3 region in setting overall properties of signal-transducing GTPases.
Surge in treatment admissions related to methamphetamine use in Cape Town, South Africa: implications for public health
Authors: PLÜDDEMANN ANDREAS , MYERS BRONWYN J. , PARRY CHARLES D. H.
Published: February 2008

Introduction and Aims. In the past decade, methamphetamine has become increasingly a drug of concern globally. The purpose of this study is to describe the changing trends in treatment admissions for methamphetamine abuse in Cape Town, South Africa and to highlight the implications of these changes for policy, practice and research. Design and Methods. Data were collected on admissions for drug abuse treatment through a regular monitoring system involving drug treatment centres and programmes in Cape Town every 6 months as part of the South African Community Epidemiology Network on Drug Use (SACENDU). A one‐page form was completed by treatment centre personnel to obtain demographic data, the patients' primary and secondary substances of abuse, the mode, frequency and age of first use of substance and information on prior treatment. Results. The results indicate that between 2004 and 2006 a dramatic increase in treatment admissions for methamphetamine abuse occurred, a large proportion of the methamphetamine patients are adolescents and that the drug is almost exclusively smoked. Discussion and Conclusions. The rapid increase in admissions for methamphetamine abuse is of great concern, particularly as the drug has a number of serious, often chronic, side effects and that a large proportion of the patients are adolescents. The implications for public health are discussed.
Can music therapy engage patients in group cognitive behaviour therapy for substance abuse treatment?
Authors: DINGLE GENEVIEVE A. , GLEADHILL LIBBY , BAKER FELICITY A.
Published: February 2008

Introduction and Aims. Despite the availability of effective treatments for substance use disorders, engaging people in treatment remains a challenge. This clinical study describes a 7‐week trial of music therapy as an adjunct to group cognitive behaviour therapy with the aim of increasing patient engagement in a private hospital open group programme. Design and Methods. Patient attendance rates and perceptions of the music therapy were collected at the end of each music therapy session by means of an anonymous survey, and only data from each patient's first survey were used in the analysis. Twenty‐four surveys were analysed, representing feedback from 10 men and 14 women, aged between 17 and 52 years. Results. The average attendance rate over the 7‐week trial was 75%. The results indicated that enjoyment and motivation to participate during the sessions was uniformly high (mean ratings of 4.3 and 4.0 out of 5, respectively). The majority (83%) of participants reported that they would attend another music therapy session, and almost half (46%) endorsed that ‘(music therapy) would help them to feel more a part of the group’. Additional analyses revealed that music therapy was able to engage patients regardless of their age group (25 years and under vs. over‐25 years) or substance (alcohol only vs. other drugs). Discussion and Conclusions. Music therapy is a promising approach to improving engagement in substance abuse treatment groups.
The effects of the market withdrawal of temazepam gel capsules on benzodiazepine injecting in Sydney, Australia
Authors: DEGENHARDT LOUISA , ROXBURGH AMANDA , VAN BEEK INGRID , HALL WAYNE D. , ROBINSON MAXINE K. F. , ROSS JOANNE , MANT ANDREA
Published: February 2008

Introduction and Aims. This study assessed the impact on benzodiazepine injection among IDU in Sydney of removing temazepam gel capsule preparations from the Australian market. Design and Methods. Several data sources were used: (1) data from the NSW Illicit Drug Reporting System (IDRS) (an annual, cross‐sectional survey of regular IDU in Sydney) for the period 1996–2005; (2) data from inner Sydney outreach services and the Sydney Medically Supervised Injecting Centre (MSIC) on last drug injected; and (3) national benzodiazepine prescription data, by formulation, from the Drug Utilisation Sub‐Committee for the period 2001–06. Results. Removal of temazepam gel capsule formulations from the Australian market in 2004 resulted in increased prescribing of tablet formulations but overall benzodiazepine prescription numbers remained stable. Injection of benzodiazepines ceased as a mode of administration of benzodiazepines among IDU in inner Sydney, but very frequent oral use of benzodiazepines remained highly prevalent. Discussion and conclusions. Removal of an easily injectable form of benzodiazepines appeared to halt injection of benzodiazepines among disadvantaged IDU. However, IDU continue to use the drug heavily and interventions to assist IDU with reducing dependent benzodiazepine use are warranted. There is a need for continued vigilance to emergent injecting drug use risks to implement timely harm reduction strategies.
Improving services for prevention and treatment of substance misuse for Aboriginal communities in a Sydney Area Health Service
Authors: TEASDALE KATHARINE E. , CONIGRAVE KATHERINE M. , KIEL KEREN A. , FREEBURN BRADLEY , LONG GEORGE , BECKER KAREN
Published: February 2008

Introduction and Aims. Substance misuse among Aboriginal Australians is both a symptom of disadvantage and suffering but also a cause of health and social problems. Few data are available on how mainstream drug and alcohol services meet the needs of Aboriginal Australians. We assessed acceptability and accessibility of mainstream services for Aboriginal Australians with alcohol or drug use disorders in an urban Area Health Service (AHS). We identified priorities for improvement and an implementation plan. Methods. We collected feedback via consultation with client groups, with the Aboriginal community and community organisations, with staff of the AHS and of the local Aboriginal Medical Service (AMS) and through direct observation. We examined attendance data. Results. Aboriginal people were well represented in this mainstream service, partly because of existing collaboration with the AMS. Good points in the service were reported to be priority appointments for new Aboriginal clients, professional and caring service and collaboration with the AMS. Suggested improvements included increased cultural sensitivity of communication, more appropriate physical surrounds and printed materials, having Aboriginal staff available, peer support groups and integration of health care for individual, family and community. The action plan included increased recruitment and career opportunities for Aboriginal staff, strengthened partnerships with the Aboriginal community, including ongoing collaboration with the AMS in improving and monitoring mainstream service quality. Discussion and Conclusions. Given the adverse impact of substance use disorders, there is a pressing need for services to work with Aboriginal communities to optimise the quality of mainstream treatment services.
Australian smokers' use of bupropion and nicotine replacement therapies and their relation to reimbursement, Australia 2001–05
Authors: LUTSENKO HERA , DORAN CHRISTOPHER M. , HALL WAYNE D.
Published: February 2008

Objective. To compare the usage of bupropion hydrochloride and nicotine replacement in Australia between 2001 and 2005. Design and Setting. We analysed aggregate data on the utilisation of: (1) bupropion under the Pharmaceutical Benefit Scheme (PBS) between 2001 and 2005; (2) bupropion and nicotine replacement therapy (NRT) on the Repatriation Pharmaceutical Benefit Scheme (RPBS) between 1995 and 2005; and (3) NRT aggregate sales data from GlaxoSmithKline for 2001–05. The National Drug Strategy Household Survey (NDSHS) 2004 was used to estimate the proportion of smokers who received a bupropion prescription in each year. Main Outcome Measures. Numbers of annual prescriptions for bupropion on the PBS and buproprion and NRT on the RPBS; annual sales figures on NRT patches (2001–05); and the estimated proportion of Australian smokers who used bupropion in 2003. Results. The number of bupropion prescriptions on the PBS peaked at 351 772 in 2001 (costing the PBS $83 million). This declined by 72% to 97 173 in 2005 (a cost of $12 million). The estimated percentage of smokers in Australia who used bupropion in a year fell from 11% in 2001 to 3.6% in 2005. The annual number of bupropion prescriptions on the RPBS fell from 3786 in 2001 to 1173 in 2005, while there was no change in the number of NRT prescriptions (3793 in 2001 and 3886 in 2005). Sales data from the leading market supplier of NRT also indicated that NRT use continued to grow in Australia while bupropion use declined. Conclusions. Bupropion usage has fallen by 72% since a peak in the year of first listing on the PBS, while the utilisation of NRTs appears to have increased, despite the price differential in favour of bupropion. Implications. Given the greater interest among smokers in NRT than bupropion (and evidence of the effectiveness and cost‐effectiveness of NRT), the Australian government should reconsider its decision not to list NRT on the PBS.
Mapping heroin careers: utilising a standardised history‐taking method to assess the speed of escalation of heroin using careers in a treatment‐seeking cohort
Authors: BEST DAVID , DAY ED , CANTILLANO VANESSA , GASTON ROMINA LOPEZ , NAMBAMALI ANGELA , SWEETING RUTH , KEANEY FRANCIS
Published: February 2008

Introduction and aims. Although there has been increasing research attention to the concept of addiction careers and treatment careers, there are few standardised measures for assessing illicit drug using careers. A new instrument for mapping lifetime drug use history (LDUH) was used to assess transitions in the initial stages of heroin use careers among illicit drug users. Design and Methods. 58 lifetime heroin users completed a one‐off researcher‐administered interview in treatment settings in two English cities, London and Birmingham, about their histories of drug use, drug treatment and other key life events. Results. The sample reported initiating heroin use at a mean age of 21 years and escalated to daily use by 23 years. On average, there was a gap of nearly 8 years before seeking treatment and at the time of interview the cohort averaged one‐third of their heroin careers in treatment. However, there was marked variability across the group, with three discernible groups identified based on use patterns. While one group (n = 21) showed consistent escalation in total quantity of heroin used across the first year, the second group had an intermittent pattern of use and the third group reported an unchanging monthly heroin use pattern. These groups differed in the time taken to initiate treatment and in the proportion of their heroin careers in active use. Discussion and Conclusions. The instrument was acceptable to research participants and identified important variability in onset and escalation factors in heroin careers. The implications for therapeutic interventions and for clinical use of the instrument are discussed.
Measuring the use and career histories of drug users in treatment: reliability of the Lifetime Drug Use History (LDUH) and its data yield relative to clinical case notes
Authors: DAY ED , BEST DAVID , CANTILLANO VANESSA , GASTON ROMINA LOPEZ , NAMBAMALI ANGELA , KEANEY FRANCIS
Published: February 2008

Introduction and Aims. There is no generally accepted clinical or research instrument available for recording the longitudinal course of a drug‐using ‘career’. This paper reports on an initial examination of the properties of the Lifetime Drug Use History Questionnaire (LDUH), built around monthly mapping of drug use patterns in relation to other life events. Design and Methods. Forty heroin and cocaine users completed structured interviews at two treatment sites. Twenty subjects were interviewed on two occasions separated by a 3‐day interval, using either the same interviewer (n= 10) or two different interviewers (n= 10) as assessments of inter‐rater and test – retest reliability. Results. Very good inter‐rater agreements were observed, demonstrated by Cronbach's alpha and intraclass correlation coefficients generally higher than 0.8 and 0.7, respectively. Additionally, concordance with clinical notes was assessed for four drug use history variables, resulting in poorer rates of agreement. An exact matching with clinical records was obtained for the variable ‘age of first use of heroin’ in 47.2% (n= 17) of the heroin users, while a good agreement (only 1 or 2 years' difference) was found in 36.1% of cases (n= 5). Discussion and Conclusions. The LDUH method resulted in high reliability for heroin and cocaine and suggests an effective, clinically applicable method for history‐taking. The paucity and inconsistency of similar information in the clinical notes would further justify the use of a standardised method for recording drug histories.