bluuebunny/crossref_metadata_2025 huggingface dataset:
Composition dependence of bilayer elasticity
Authors: Brannigan Grace , Brown Frank L. H.
Published: February 2005

A previously developed molecular level model for homogeneous lipid bilayers [Brannigan and Brown, J. Chem. Phys 120, 1059 (2004)] is extended to allow for multiple lipid species. Monte Carlo simulations (including species exchange moves for efficient sampling) reveal a variety of mixing behaviors in binary systems. Two species are identified that maintain stable, randomly mixed fluid membranes at vanishing tension over all possible binary compositions. The thermal and elastic properties of membranes formed by these lipids are characterized over the full composition range. Equilibrium area at constant tension is nonmonotonic with respect to composition, but consistent with that of a quadratic mixture. In the constant tension ensemble, the bending rigidity of the bilayer is minimized at an intermediate composition. The observed functional form of bending rigidity vs composition is fit to a simple expression motivated by linear elasticity theory; this expression accounts for membrane heterogeneity through a single parameter.
Magnetization dependence on electron density in epitaxial ZnO thin films codoped with Mn and Sn
Authors: Ivill M. , Pearton S. J. , Norton D. P. , Kelly J. , Hebard A. F.
Published: February 2005

The magnetic and transport properties of Mn-doped ZnO thin films codoped with Sn are examined. Superconducting quantum interference device magnetometry measurements indicate that the films are ferromagnetic with an inverse correlation between magnetization and electron density as controlled by Sn doping. Magnetism in low free-electron density material is consistent with the bound magnetic polaron model, in which bound acceptors mediate the ferromagnetic ordering. Increasing the electron density decreases the acceptor concentration, thus quenching the ferromagnetic exchange. This result is important in understanding ferromagnetism in transition-metal-doped semiconductors for spintronic devices.
Submillisecond switching of nematic liquid crystal in cells fabricated by anisotropic phase-separation of liquid crystal and polymer mixture
Authors: Wang Qingbing , Kumar Satyendra
Published: February 2005

Liquid crystal (LC) cells consisting of a very thin (submicrometer) nematic LC layer switch with time response smaller than 1ms. The total response time, i.e., sum of the turn-on and turn-off times, can be made as small as 1.3ms. Such devices were prepared by a photoinduced anisotropic phase separation of mixtures of the LC and prepolymer. The formation of the LC–polymer bilayer in these devices was confirmed by polarized light microscopy and scanning electron microscopy. The phase separation method permits one to fine-tune the LC film thickness by varying the LC concentration in the mixture. This technique can be used to fabricate fast LC devices for TV and video applications.
Consequences of strong coupling between excitons and microcavity leaky modes
Authors: Richard Maxime , Romestain Robert , André Régis , Dang Le Si
Published: February 2005

Semiconductor microcavities are known to exhibit the so-called leaky modes due to the Bragg structure of the cavity mirrors. In case of microcavities operating in the strong coupling regime, the leaky modes are usually considered as a perturbation for the polariton modes. Using microcavities based on II–VI compounds we observed that leaky modes and excitons can be strongly coupled and lead to complex multimode polaritons. The consequences for photoluminescence under nonresonant excitation and potential applications are discussed in terms of polariton state occupancy and photonic weight.
High optical quality GaN nanopillar arrays
Authors: Wang Y. D. , Chua S. J. , Tripathy S. , Sander M. S. , Chen P. , Fonstad C. G.
Published: February 2005

GaN nanopillar arrays have been fabricated by inductively coupled plasma etching of GaN films using anodic aluminum oxide film as an etch mask. The average diameter and length of these pillars are 60–65nm and 350–400nm, respectively. Ultraviolet microphotoluminescence measurements indicate high photoluminescence intensity and stress relaxation in these GaN nanopillars as compared to the starting epitaxial GaN films. Evidence of good crystalline quality is also observed by micro-Raman measurements, wherein a redshift of the E2high mode from GaN nanopillars suggests partial relaxation of the compressive strain. In addition, breakdown of the polarization selection rules led to the appearance of symmetry-forbidden and quasipolar modes.
Tensile test of a single nanofiber using an atomic force microscope tip
Authors: Tan E. P. S. , Goh C. N. , Sow C. H. , Lim C. T.
Published: February 2005

In this study, an approach using an atomic force microscope (AFM) tip to stretch a single electrospun polyethylene oxide (PEO) nanofiber is demonstrated. One end of the nanofiber is attached to a movable optical microscope stage and the other end of the nanofiber to a piezoresistive AFM cantilever tip. The nanofiber is stretched by moving the microscope stage and the force is measured via the deflection of the cantilever. The elastic modulus of PEO nanofiber is found to be about 45MPa.
Interaction of a laser-produced plume with a second time delayed femtosecond pulse
Authors: Scuderi D. , Albert O. , Moreau D. , Pronko P. P. , Etchepare J.
Published: February 2005

Time resolved emission spectroscopy coupled with a secondary time-delayed femtosecond pulse technique has been used to study laser–matter interaction that occurs within ablation processes from a solid target, in the 1012–1014W∕cm2 energy range. It allows an examination of the emitted optical signals that characterize the species escaping from the target, namely ions, neutrals, and nanoparticles. Size distributions of nanoparticles are deduced from an analysis of the deposition substrate. The newest result concerns the huge drop of emission signal from the nanoparticles, which occurs at a delay (0.8<Δt<1ns) and has been attributed to a fragmentation process.
Negative capacitance in organic light-emitting diodes
Authors: Pingree L. S. C. , Scott B. J. , Russell M. T. , Marks T. J. , Hersam M. C.
Published: February 2005

Negative capacitance has been characterized in organic light-emitting diode (OLED) heterostructures using impedance spectroscopy. Although similar inductive behavior has been previously reported for transient electroluminescence in OLEDs, definitive identification of negative capacitance in impedance spectroscopy data has been elusive due to the high concentration of distributed traps at the anode-organic interface. The addition of a layer of 4,4′-bis[(p-trichlorosilylpropylphenyl)phenylamino]-biphenyl at this interface minimizes these trapping sites, thus enabling the inductive nature of charge transport in OLEDs to be directly observable. By quantitatively correlating the resulting impedance spectroscopy data with equivalent circuit models, a detailed description of charge transport in OLEDs as a function of heterostructure composition is developed.
Hafnium oxide films by atomic layer deposition for high-κ gate dielectric applications: Analysis of the density of nanometer-thin films
Authors: Puurunen Riikka L. , Delabie Annelies , Van Elshocht Sven , Caymax Matty , Green Martin L. , Brijs Bert , Richard Olivier , Bender Hugo , Conard Thierry , Hoflijk Ilse , Vandervorst Wilfried , Hellin David , Vanhaeren Danielle , Zhao Chao , De Gendt Stefan , Heyns Marc
Published: February 2005

The density of hafnium oxide films grown by atomic layer deposition for high-κ gate dielectric applications was investigated for films with thickness in the nanometer range. The density, measured by combining the film thickness from transmission electron microscopy with the amount of hafnium deposited from Rutherford backscattering, decreased with decreasing film thickness. The dielectric constant of hafnium oxide remained constant with decreasing film thickness, however. The main reason for the decrease in the measured density seemed not to be a decrease in the inherent material density. Instead, the relative importance of interface roughness in the density measurement increased with decreasing film thickness.
Flexoelectric effect in ceramic lead zirconate titanate
Authors: Ma Wenhui , Cross L. Eric
Published: February 2005

Mechanical strain gradient generated electric polarization or flexoelectric effect was investigated in unpoled lead zirconate titanate (PZT) ceramics in the ferroelectric state by using a cantilevered beam based approach. Flexoelectric coefficient μ12 at room temperature was measured to be 1.4μC∕m in the PZT ceramic at small level of strain gradient. Temperature-dependent experimental investigations clearly showed that high dielectric permittivity in the ferroelectrics enhanced flexoelectric polarization: essentially a linear relation was found to exist between μ12 and dielectric susceptibility χ at lower permittivity level (2100–2800), while μ12 versus χ curve started to deviate from the straight line at the χ∼2800 and nonlinear enhancement of μ12 with χ was observed, with μ12 value reaching 9.5 at χ∼11000. The nonlinearity in the flexoelectric effect was associated with domain-related processes. It is suggested that flexoelectric effect can have a significant impact on epitaxial ferroelectric thin films and mesoscopic structures.
Bending experiment on pentacene field-effect transistors on plastic films
Authors: Sekitani Tsuyoshi , Kato Yusaku , Iba Shingo , Shinaoka Hiroshi , Someya Takao , Sakurai Takayasu , Takagi Shinichi
Published: February 2005

We have fabricated very flexible pentacene field-effect transistors with polyimide gate dielectric layers on plastic films with a mobility of 0.3cm2∕Vs and an on/off ratio of 105, and have measured their electrical properties under various compressive and tensile strains while changing the bending radius of the base plastic films systematically. We have found that the change in source-drain current with bending radius is reproducible and reversible when the bending radius is above 4.6mm, which corresponds to strains of ∼1.4±0.1%. Furthermore, the change in source-drain current does not depend on the direction of strain versus direction of current flow.
Room temperature ferromagnetism in bulk Mn-Doped Cu2O
Authors: Wei M. , Braddon N. , Zhi D. , Midgley P. A. , Chen S. K. , Blamire M. G. , MacManus-Driscoll J. L.
Published: February 2005

Bulk Mn-doped Cu2O samples were produced by reacting Cu2O and Mn2O3 powders in Ar gas at 650 and 800°C to give a nominal composition of 1.7at.% Mn-doped Cu2O. From x-ray energy dispersive spectrum analysis, the actual doping level was lower at 0.3–0.5at.% Mn. Room temperature ferromagnetism with a coercive field of 50Oe was found in the 650°C samples. The Curie temperature (TC) of samples sintered at 650°C was above 300K, whereas for 800°C samples it was 215±5K. Using the nominal doping level, the magnetization saturation value was calculated to be ∼0.4μB∕Mn at 10K.
Increasing Reading Speed by Using Colours: Issues concerning Reliability and Specificity, and Their Theoretical and Practical Implications
Authors: Wilkins Arnold J , Sihra Nirmal , Myers Andrew
Published: February 2005

By using techniques for precision ophthalmic tinting, individuals who report perceptual distortion of text can often find a colour of illumination that eliminates the distortions and increases reading speed. Most individuals choose green or blue hues, but there is considerable variability. We investigated how specific the colour has to be to obtain optimal reading speed.

Individuals who habitually wear coloured filters for reading were asked to read text illuminated by coloured light (without using their filters). Reading speed was measured repeatedly with light of different colours. The colour (chromaticity) at which reading was fastest was consistent from one test session to the next. It was different from one individual to another, but highly specific for each individual: departures of colour from optimum by about 6 JNDs eliminated most of the speed advantage conferred by the optimal colour. It was difficult to attribute the consistency and specificity simply to familiarity with the tint or immediate memory for the colour of illumination.

A consecutive sample of 1000 tint prescriptions was analysed numerically. For most prescriptions the variation in chromaticity with different types of lighting was not such as to remove all the potential benefit of the tint, as judged from a model of the effect of chromaticity on reading speed. The exceptions were the few tints that were weakly saturated or purple in colour.

Across participants, reading speed was not consistently related to the scotopic energy, to the energy captured by any cone class, or to opponent colour processes. The reading was generally slowest with white light, and not with the colour complementary to the optimum. Explanations in terms of magnocellular deficits and cortical hyperexcitability are briefly discussed.
Bursicon, the insect cuticle-hardening hormone, is a heterodimeric cystine knot protein that activates G protein-coupled receptor LGR2
Authors: Luo Ching-Wei , Dewey Elizabeth M. , Sudo Satoko , Ewer John , Hsu Sheau Yu , Honegger Hans-Willi , Hsueh Aaron J. W.
Published: February 2005

All arthropods periodically molt to replace their exoskeleton (cuticle). Immediately after shedding the old cuticle, the neurohormone bursicon causes the hardening and darkening of the new cuticle. Here we show that bursicon, to our knowledge the first heterodimeric cystine knot hormone found in insects, consists of two proteins encoded by the genes
burs
and
pburs
(
partner of burs
). The pburs/burs heterodimer from
Drosophila melanogaster
binds with high affinity and specificity to activate the G protein-coupled receptor DLGR2, leading to the stimulation of cAMP signaling
in vitro
and tanning in neck-ligated blowflies. Native bursicon from
Periplaneta americana
is also a heterodimer. In
D. melanogaster
the levels of
pburs
,
burs
, and DLGR2 transcripts are increased before ecdysis, consistent with their role in postecdysial cuticle changes. Immunohistochemical analyses in diverse insect species revealed the colocalization of pburs- and burs-immunoreactivity in some of the neurosecretory neurons that also express crustacean cardioactive peptide. Forty-three years after its initial description, the elucidation of the molecular identity of bursicon and the verification of its receptor allow for studies of bursicon actions in regulating cuticle tanning, wing expansion, and as yet unknown functions. Because bursicon subunit genes are homologous to the vertebrate bone morphogenetic protein antagonists, our findings also facilitate investigation on the function of these proteins during vertebrate development.
Probability models to facilitate a declaration of pest-free status, with special reference to tsetse (Diptera: Glossinidae)
Authors: Barclay H.J. , Hargrove J.W.
Published: February 2005

A methodology is presented to facilitate a declaration that an area is ‘pest-free’ following an eradication campaign against an insect pest. This involves probability models to assess null trapping results and also growth models to help verify, following a waiting period, that pests were not present when control was stopped. Two probability models are developed to calculate the probability of negative trapping results if in fact insects were present. If this probability is sufficiently low, then the hypothesis that insects are present is rejected. The models depend on knowledge of the efficiency and the area of attractiveness of the traps. To verify the results of the probability model, a waiting period is required to see if a rebound occurs. If an incipient but non-detectable population remains after control measures are discontinued, then a rebound should occur. Using a growth model, the rate of increase of an insect population is examined starting from one gravid female or one male and a female. An example is given for tsetse in which both means and confidence limits are calculated for a period of 24 reproductive periods after control is terminated. If no rebound is detected, then a declaration of eradication can be made.
Whole-grain rye and wheat alkylresorcinols are incorporated into human erythrocyte membranes
Authors: Linko Anna-Maria , Adlercreutz Herman
Published: February 2005

Alkylresorcinols (AR), a group of phenolic lipids, exist in the human diet in whole-grain rye and wheat. They are absorbed by humans and have been quantified in plasma. In this 2-week study we assessed AR incorporation into human erythrocyte membranes. Nine subjects attended the study; four avoided whole-grain products for 1 week and then included whole-grain rye and wheat bread in the diet for the second week, four included whole-grain rye and wheat products in the diet during the whole follow-up and one followed a gluten-free diet. Plasma and erythrocyte membrane AR were analysed after weeks 1 and 2. Erythrocyte membrane AR concentrations increased an average of 231 nmol/l of packed erythrocytes (P=0·036) after consumption of whole-grain rye and wheat products. Plasma AR levels increased an average of 175 nmol/l (P=0·058) When intake of whole-grain products was constant, erythrocyte membrane and plasma AR levels remained stable. Long-chain AR were incorporated into erythrocyte membranes in a higher proportion compared to shorter-chain AR. This preliminary study shows that AR are incorporated into human erythrocyte membranesin vivo.
Differences in labelled triolein turnover after oral administration between liver and adipose tissue of rats
Authors: Iritani Nobuko , Kimura Tomoe , Fukuda Hitomi , Sugimoto Tomomi
Published: February 2005

To investigate exogenous triacylglycerol turnover, the time courses for labelled triolein in the liver, plasma and epididymal adipose tissue (adipose tissue) after oral administration to rats fed a fat-free or 10 % corn oil diet for 3 d after fasting overnight were examined for 10 d. After the administration of labelled triolein to rats fed the fat-free diet, the incorporation (dpm/g) into total lipids of the liver and adipose tissue each reached the maximum in 8 h and was seven times higher in the adipose tissue than in the liver. The half-lives of total lipid radioactivities during the decreasing phases were 0·39 and 2·58 d, respectively, in the rapid and slow phases of the decay curve in the liver, and 4·78 d in only one phase of the adipose tissue. Radioactivity after administration of labelled triolein was mostly found in the oleic acid in the tissues. The half-life of oleic acid was 3·92 d in the adipose tissues. These half-lives were similar in both dietary groups. Thus, although dietary corn oil reduced the triolein incorporation to cellular lipids in comparison to the fat-free diet, it did not affect these half-lives. The labelled triacylglycerol–oleic acid stayed abundantly intact for a long time in the adipose tissue and was scarcely changed to other fatty acids, whereas it was slightly incorporated into total lipids and quickly metabolized in the liver. Non-essential fatty acids may be mostly endogenous in the liver but may be exogenous and endogenous in adipose tissue.
Influence of dietary spices on the fluidity of erythrocytes in hypercholesterolaemic rats
Authors: Kempaiah Rayavara K. , Srinivasan Krishnapura
Published: February 2005

In rats rendered hypercholesterolaemic by maintaining them on a cholesterol-enriched diet (0·5 %) for 8 weeks, as a result of alteration in membrane structural lipids, erythrocytes were observed to be deformed and become more fragile. This deformity and fragility was partially reversed by the two dietary spice principles, curcumin and capsaicin, and the spice, garlic, by virtue of their ability to lower the extent of hypercholesterolaemia. A further insight into the factors that might have reduced the fluidity of erythrocytes in hypercholesterolaemic rats revealed changes in fatty acid profile of the membranes, phospholipid composition of the membrane bilayer, reduced Ca2+, Mg2+-ATPase, and reduction in the sensitivity of erythrocytes to concanavaline A. Dietary capsaicin appeared to counter these changes partially in hypercholesterolaemic rats. Electron spin resonance (ESR) spectra and fluorescence anisotropy parameters also revealed altered fluidity of erythrocytes in hypercholesterolaemic rats. Dietary capsaicin and curcumin significantly reversed this alteration. Scanning electron microscopic examination revealed that the echinocyte population was increased in the erythrocytes of hypercholesterolaemic rats, and this was significantly countered by dietary capsaicin. The membrane protein profile and the active cation efflux appeared to be unaffected in the hypercholesterolaemic situation.
SNX9 Regulates Dynamin Assembly and Is Required for Efficient Clathrin-mediated Endocytosis
Authors: Soulet Fabienne , Yarar Defne , Leonard Marilyn , Schmid Sandra L.
Published: February 2005

Dynamin, a central player in clathrin-mediated endocytosis, interacts with several functionally diverse SH3 domain-containing proteins. However, the role of these interactions with regard to dynamin function is poorly defined. We have investigated a recently identified protein partner of dynamin, SNX9, sorting nexin 9. SNX9 binds directly to both dynamin-1 and dynamin-2. Moreover by stimulating dynamin assembly, SNX9 stimulates dynamin's basal GTPase activity and potentiates assembly-stimulated GTPase activity on liposomes. In fixed cells, we observe that SNX9 partially localizes to clathrin-coated pits. Using total internal reflection fluorescence microscopy in living cells, we detect a transient burst of EGFP-SNX9 recruitment to clathrin-coated pits that occurs during the late stages of vesicle formation and coincides spatially and temporally with a burst of dynamin-mRFP fluorescence. Transferrin internalization is inhibited in HeLa cells after siRNA-mediated knockdown of SNX9. Thus, our results establish that SNX9 is required for efficient clathrin-mediated endocytosis and suggest that it functions to regulate dynamin activity.
Roots of Withania somnifera Inhibit Forestomach and Skin Carcinogenesis in Mice
Authors: Padmavathi Bandhuvula , Rath Pramod C. , Rao Araga Ramesha , Singh Rana Pratap
Published: February 2005

We evaluated the cancer chemopreventive efficacy of the Withania somnifera root, which has been used in the Indian traditional medicine system for many centuries for the treatment of various ailments. Since, studies showing its mechanism‐based cancer chemopreventive efficacy are limited, this was investigated in the present study. We studied the effect of dietary administration of Withania root on hepatic phase I, phase II and antioxidant enzymes by estimation of its level/activity, as well as in attenuating carcinogen‐induced forestomach and skin tumorigenesis in the Swiss albino mouse model. Our findings showed that roots of W.somnifera inhibit phase I, and activates phase II and antioxidant enzymes in the liver. Further, in a long‐term tumorigenesis study, Withania inhibited benzo(a)pyrene‐induced forestomach papillomagenesis, showing up to 60 and 92% inhibition in tumor incidence and multiplicity, respectively. Similarly, Withania inhibited 7,12‐dimethylbenzanthracene‐induced skin papillomagenesis, showing up to 45 and 71% inhibition in tumor incidence and multiplicity. In both studies, Withania showed no apparent toxic effects in mice as monitored by the body weight gain profile. Together, these findings suggest that W.somnifera root has chemopreventive efficacy against forestomach and skin carcinogenesis and warrants the identification and isolation of active compounds responsible for its anticancer effects, which may provide the lead for the development of antitumor agents.
Anti‐anxiety Activity Studies on Homoeopathic Formulations of Turnera aphrodisiaca Ward
Authors: Kumar Suresh , Sharma Anupam
Published: February 2005

Turnera aphrodisiaca Ward (Turneraceae) has been traditionally used for the treatment of anxiety neurosis, and as an aphrodisiac. Mother tinctures (85% ethanol extracts) of T. aphrodisiaca have also been used for the treatment of central nervous system disorders. In the present investigation, T. aphrodisiaca mother tinctures formulated by three reputed manufacturers of homoeopathic medicines (NLK, DWSG and SBL) were evaluated for their anxiolytic activity. Dried mother tinctures of T. aphrodisiaca were subjected to anxiolytic activity evaluation at various doses, i.e. 50, 75, 100, 125 or 150 mg/kg p.o. in mice using elevated plus maze apparatus. Dried mother tinctures exhibited significant anxiolytic activity at 50 mg/kg (NLK), 75 mg/kg (DWSG) and 125 mg/kg (SBL), respectively, with reference to control as well as standard (diazepam, 2 mg/kg p.o.). Mother tinctures of T. aphrodisiaca available in the market, have significant anxiolytic activity. Amongst the three mother tinctures of T. aphrodisiaca analyzed, the dry residue of NLK possesses the highest amount of anxiolytic constituent(s). To ensure uniformity and consistency of biological effects in herbal formulations, these should be standardized on the basis of bioactive markers. The authors are actively involved in isolating the bioactive constituent(s) from T. aphrodisiaca so that the plant can be standardized on the basis of biologically active constituent(s).
Neuro–evolutionary patterning of sociality
Authors: Goodson James L. , Evans Andrew K. , Lindberg Laura , Allen Camryn D.
Published: February 2005

Evolutionary shifts in species–typical group size (‘sociality’) probably reflect natural selection on motivational processes such as social arousal, approach–avoidance, reward, stress/anxiety and dominance. Using four songbird species that differ selectively in sociality (one territorial, one modestly gregarious, and two highly gregarious species), we here examined immediate early gene (IEG) responses of relevant brain regions following exposure to a same–sex conspecific. The paradigm limited behavioural performance, thus species differences should reflect divergence in motivational and/or perceptual processes. Within the extended medial amygdala (which is involved in appetitive approach, social arousal and avoidance), we observed species differences in IEG response that are negatively graded in relation to sociality. In addition, brain areas that are involved in social stress and dominance–related behaviour (ventrolateral septum, anterior hypothalamus and lateral subdivision of the ventromedial hypothalamus) exhibited IEG responses that dichotomously distinguish the territorial species from the three gregarious species. The IEG responses of areas involved in reward (nucleus accumbens and ventral pallidum) and general stress processes (e.g. paraventricular hypothalamus, lateral bed nucleus of the stria terminalis and most areas of the lateral septum) do not correlate with sociality, indicating that social evolution has been accompanied by selection on a relatively discrete suite of motivational systems.
Convergent incidences ofWolbachiainfection in fig wasp communities from two continents
Authors: Haine Eleanor R. , Cook James M.
Published: February 2005

Wide surveys suggest thatWolbachiabacteria infectca. 20% of all insect species, but particular taxonomic or ecological groups may display significantly higher or lower incidences. We studied 61 fig wasp species in Australia and found the highest known incidence (67%) of infection in a targeted study of this nature. A comparable study in Panama reported a similar figure (59%), confirming the exceptionally high incidence ofWolbachiain fig wasps. Importantly, these are two independent estimates ofWolbachiaincidence in fig wasp communities, because no host species, or even genera, are shared between localities. The high level of infection may reflect enhanced opportunities for horizontal transmission inside fig fruits. Although incidence was similar in Panama and Australia, the actual strains involved were different and region–specific. Local strains were shared by several host species, although there was often no obvious (direct) ecological link between two hosts with the same infection.
‘100 years of peptide synthesis’: ligation methods for peptide and protein synthesis with applications to β‐peptide assemblies*
Authors: Kimmerlin T. , Seebach D.
Published: February 2005

Abstract:  A brief survey of the history of peptide chemistry from Theodore Curtius to Emil Fischer to Bruce Merrifield is first presented. The discovery and development of peptide ligation, i.e. of actual chemical synthesis of proteins are described. In the main chapter, ‘Synthesis of Proteins by Chemical Ligation’ a detailed discussion of the principles, reactivities and mechanisms involved in the various coupling strategies now applied (ligation, chemical ligation, native chemical ligation) is given. These include coupling sites with cysteine and methionine (as well as the seleno analogs), histidine, glycine and pseudo‐prolines, ‘unrestricted’ amino‐acid residues (using the Staudinger reaction), as well as solid‐phase segment coupling by thioligation of unprotected peptides. In another section, ‘Synthesis of β‐peptides by Thioligation’, couplings involving β2‐ and β3‐peptides are described (with experimental details).
133Xenon ventilation scintigraphy applied to bronchoscopic lung volume reduction techniques for emphysema: relevance of interlobar collaterals
Authors: Salanitri J. , Kalff V. , Kelly M. , Holsworth L. , Williams T. , Snell G.
Published: February 2005

Abstract

Background:  133Xenon ventilation scintigraphy and 99mTc‐MAA perfusion scintigraphy can be used to assess dynamic ventilation patterns in patients with severe emphysema.

Aim:  To describe the scintigraphic features of attempted bronchoscopic lung volume reduction (BLVR), exploring mechanisms that might explain the unexpected lack of postoperative atelectasis.

Methods:  Five patients with heterogenous severe upper lobe emphysema were evaluated with 133Xenon ventilation and 99mTc‐MAA perfusion scintigraphy, chest radiography, bronchoscopy and high resolution computed tomography before and up to 1 month after endoscopic placement of bronchial prostheses (BLVR). Ex vivo assessment of the lungs of two further patients with severe upper lobe emphysema was performed.

Results:  No significant subsegmental or lobar collapse was evident on post‐procedure chest radiography or high resolution computed tomography, despite bronchoscopic confirmation of adequate position and functioning of prostheses. 133Xenon ventilation scintigraphy confirms significantly decreased upper lobe wash‐in (P < 0.023), unchanged lower lobe wash‐in and significantly increased lower lobe wash‐out rates (P < 0.005) after BLVR. Significant redistribution of perfusion to the lower lobes occurred after BLVR (P < 0.025). Ex vivo experiments on explanted emphysematous lungs demonstrated that these findings could best be explained by collateral interlobar ventilation, which was calculated in one specimen to be as high as 15% of total lower lobe ventilation. Peri‐valvular leak is a much less likely possibility.

Conclusion:  133Xenon ventilation scintigraphy indicated the presence of significant interlobar collateral ventilation in patients with severe emphysema that may have major relevance to these novel alternative techniques to lung volume reduction surgery. 133Xenon scintigraphy can be used in the evaluation of severe emphysema before and after novel therapeutic interventions. (Intern Med J 2005; 35: 97*ndash;103)
Benefits and challenges brought by improved results from in vitro fertilization
Authors: Jansen R. P. S.
Published: February 2005

In vitro fertilization (IVF), in which preimplantation‐stage embryos are produced after ovarian stimulation and retrieval of preovulatory oocytes, now accounts for almost 2% of all births in Australia. For clinics performing in the top quartile of national results, the chance of a live birth for a woman under 35 years from one round of egg retrieval and IVF treatment is greater than 50%, albeit still with a greater than 20% risk of twins or higher order multiple pregnancy. Similar or better live birth rates are now obtainable with the elective transfer of a single embryo at the stage of blastocyst (5–6 days in culture), a policy that if adopted for younger women can reduce the risk of twins in a clinic to less than 15%. Current developments centre around improvements to embryo culture and the testing of embryos for chromosomal normality and other genetic and epigenetic variables before transfer, made possible by licences for embryo research protocols now being issued under the Commonwealth's Research Involving Human Embryos Act 2002. (Intern Med J 2004; 35: 108–117)
Abrupt Onset and Termination of Cutaneous Allodynia (Central Sensitization) During Attacks of SUNCT
Authors: Rozen Todd D. , Haynes Gary V. , Saper Joel R. , Sheftell Fred D.
Published: February 2005

The presence of central sensitization and cutaneous allodynia has not been readily studied in other primary headache syndromes outside of migraine. If central sensitization does occur, is the temporal profile any different in the short‐lasting more aggressive syndromes such as SUNCT than in migraine? A patient with SUNCT was examined during and in between attacks looking for the presence and duration of cutaneous allodynia.
Symptomatic Hemicrania Continua After Internal Carotid Artery Dissection
Authors: Rogalewski Andreas , Evers Stefan
Published: February 2005

We report a male patient with a right internal carotid artery (ICA) dissection and a consecutive hemicrania continua (HC) fulfilling the criteria of the International Headache Society. This is the first time that a HC secondary to ICA dissection has been reported.
Hospital Readmission From Home Health Care Before and After Prospective Payment
Authors: Anderson Mary Ann , Clarke Mara M. , Helms Lelia B. , Foreman Marquis D.
Published: February 2005

Purpose:

To describe and compare clients who were readmitted to the hospital during an episode of home health care, before and after the inception of the prospective payment system (PPS).

Design:

A longitudinal mixed design was used to replicate a study conducted 9 years previously (pre‐PPS) in the same home care agency in the central part of the United States.

Methods:

Seventy‐six closed‐case medical records from a not‐for‐profit hospital‐affiliated home care agency were retrospectively reviewed and compared to pre‐PPS data. The same data collection tool, the Hospital Readmission Inventory, was used for both pre‐ and post‐PPS studies. Nurse administrators at the data collection agency were interviewed concerning comparative results.

Findings:

Currently readmitted clients were sicker than were those in the previous research report, they were readmitted sooner for a different diagnosis, and they had less continuity of services.

Conclusions:

The home health care industry has undergone a dramatic change in payment for services, from fee‐for‐service to PPS. Of particular concern is the adverse patient outcome of an unplanned hospital readmission. Prior studies have characterized such patients in home health care, but no comparative reports were found in a literature search since the inception of PPS. Findings from this study indicated that an increased emphasis on cost containment and higher‐risk clients appear to have changed patterns of care delivery.
Nonadherence With Diet and Fluid Restrictions Among Adults Having Hemodialysis
Authors: Kugler Christiane , Vlaminck Hans , Haverich Axel , Maes Bart
Published: February 2005

Purpose:

To describe the prevalence of nonadherence with the prescribed diet and fluid restrictions among patients receiving hemodialysis.

Methods:

A multicenter cross‐sectional design with 916 patients recruited from 18 dialysis centers in Germany and Belgium. The Dialysis Diet and Fluid Nonadherence Questionnaire (DDFQ) was used to measure patients' nonadherence.

Findings:

The results showed that many patients had difficulty following diet (81.4%) and fluid (74.6%) restrictions. Younger male patients and smokers were at highest risk for nonadherence. Higher levels of interdialysis weight gain were associated with nonadherence.

Conclusions:

The findings indicate the need to continue to monitor and study hemodialysis patients' adherence behavior longitudinally and to design interventions to enhance adherence.
Action Responses of Congolese Refugee Women
Authors: Pavlish Carol
Published: February 2005

Purpose:

To describe Congolese refugee women's action responses to difficult living situations.

Design:

Interpretive qualitative.

Methods:

Narrative data were collected from 14 Congolese refugee women using minimally structured interviews and were analyzed for patterns in their responses to their difficult situations.

Findings:

The narratives about participants' difficult circumstances indicated six action responses: refiguration, advocacy, resistance, resignation, sorrow, and faith.

Conclusions:

When encountering difficult life circumstances, refugee participants demonstrated actions with varying influence on their agency.
c
is the speed of light, isn’t it?
Authors: Ellis George F. R. , Uzan Jean-Philippe
Published: February 2005

Theories for a varying speed of light have been proposed as an alternative way of solving several standard cosmological problems. Recent observational hints that the fine structure constant may have varied over cosmological scales have given impetus to these theories. However, the speed of light is hidden in many physics equations and plays different roles in them. We discuss these roles to shed light on proposals for varying speed of light theories. We also emphasize the requirements for attaining consistency of the resulting equations, when what was previously a constant is made a dynamical variable.
Independent Origins of Middle Ear Bones in Monotremes and Therians
Authors: Rich Thomas H. , Hopson James A. , Musser Anne M. , Flannery Timothy F. , Vickers-Rich Patricia
Published: February 2005

A dentary of the oldest known monotreme, the Early Cretaceous
Teinolophos trusleri
, has an internal mandibular trough, which in outgroups to mammals houses accessory jaw bones, and probable contact facets for angular, coronoid, and splenial bones. Certain of these accessory bones were detached from the mandible to become middle ear bones in mammals. Evidence that the angular (homologous with the mammalian ectotympanic) and the articular and prearticular (homologous with the mammalian malleus) bones retained attachment to the lower jaw in a basal monotreme indicates that the definitive mammalian middle ear evolved independently in living monotremes and therians (marsupials and placentals).
Deer Browsing and Population Viability of a Forest Understory Plant
Authors: McGraw James B. , Furedi Mary Ann
Published: February 2005

American ginseng is the premier medicinal plant harvested from the wild in the United States. In this study, seven populations of ginseng plants were censused every 3 weeks during the growing season over 5 years to monitor deer browse and harvest and to project population growth and viability. The minimum viable population size was ∼800 plants, a value greater than that of all populations currently being monitored. When simulated deer browsing rates were reduced 50% or more, population viability rose sharply. Without more effective deer population control, ginseng and many other valuable understory herbs are likely to become extinct in the coming century.
Methylation as a Crucial Step in Plant microRNA Biogenesis
Authors: Yu Bin , Yang Zhiyong , Li Junjie , Minakhina Svetlana , Yang Maocheng , Padgett Richard W. , Steward Ruth , Chen Xuemei
Published: February 2005

Methylation on the base or the ribose is prevalent in eukaryotic ribosomal RNAs (rRNAs) and is thought to be crucial for ribosome biogenesis and function. Artificially introduced 2′-
O
-methyl groups in small interfering RNAs (siRNAs) can stabilize siRNAs in serum without affecting their activities in RNA interference in mammalian cells. Here, we show that plant microRNAs (miRNAs) have a naturally occurring methyl group on the ribose of the last nucleotide. Whereas methylation of rRNAs depends on guide RNAs, the methyltransferase protein HEN1 is sufficient to methylate miRNA/miRNA* duplexes. Our studies uncover a new and crucial step in plant miRNA biogenesis and have profound implications in the function of miRNAs.
From Pedigree Cats to Fluffy-Bunnies
Authors: Dunningham Jacob , Rau Alexander , Burnett Keith
Published: February 2005

We consider two distinct classes of quantum mechanical entanglement. The first “pedigree” class consists of delicate highly entangled states, which hold great potential for use in future quantum technologies. By focusing on Schrödinger cat states, we demonstrate not only the possibilities these states hold but also the difficulties they present. The second “fluffy-bunny” class is made up of robust states that arise naturally as a result of measurements and interactions between particles. This class of entanglement may be responsible for the classical-like world we see around us.
Optimum Growth Conditions of Ge–Sb–Te Alloy Thin Film Investigated by Ellipsometry
Authors: An Sung Hyuck , Li Xuezhe , Kim Sang Youl
Published: February 2005

The ellipsometric constants ψ and Δ of phase changing Ge2Sb2Te5 (GST) used as an optical recording medium were collected during film growth, and the optimum growth conditions of GST thin film were investigated by varying variables such as Ar gas pressure, DC power and substrate temperature. The density distribution of postgrowth GST thin films was determined by ex situ spectroellipsometry. Based on density distribution information of the postgrown GST thin films, the evolution of density distribution of GST thin films during growth was monitored using an in situ ellipsometer. Based on ellipsometric analysis, we found that the optimum growth conditions for attaining the most homogeneous density distribution are Ar gas pressure of 7 mTorr, DC power of 45 W, and substrate temperature of 150°C. These optimum growth conditions were independently verified from scanning electron microscopy (SEM) images.
Feasibility of Cu/a-Si Bilayer for High Data-Transfer-Rate Write-Once Blue-Ray Recording
Authors: Her Yung-Chiun , Wu Chun-Lin
Published: February 2005

The formation of Cu3Si phase, and the subsequent crystallization of the remaining amorphous Si were observed in the Cu/a-Si bilayer under thermal and laser pulse annealing. The crystallization temperature of the a-Si layer with a thin Cu underlayer was reduced to 485°C due to the formation of Cu3Si precipitates that serve as nucleation sites for the crystallization of the remaining amorphous Si. At the wavelength of 405 nm, the Cu/a-Si bilayer exhibited an optical contrast of 15.4% and an absorptance of 47% providing high readability and adequate recording sensitivity. Moreover, the maximum data-transfer-rates that can be achieved by the Cu/a-Si bilayer at recording powers of 6, 8, and 10 mW were estimated to be approximately 23, 46, and 223 Mb/s, respectively. It is evident that the Cu/a-Si bilayer shows great feasibility for high data-transfer-rate write-once blue-ray recording.
Water Analysis by Laser-Induced Shock Wave Plasma Spectroscopy Using Re-crystallized KBr Powder Confined in a Cylindrical Tube
Authors: Oki Hisaya , Suyanto Hery , Kurniawan Hendrik , Lie Tjung Jie , Lee Yong Inn , Sakan Fujio , Idris Nasrullah , Kagawa Kiichiro
Published: February 2005

It has been demonstrated that shock wave plasma is produced even for a powder sample when a Q-sw Nd:YAG laser beam was focused at a reduced pressure on the surface of powder confined in a small vertical hole. KBr powder was dissolved in the water to be analyzed, and the water was boiled. The re-crystallized KBr, which consisted of trapped impurities present in the water, was contained in the hole to be irradiated by the laser pulse at low pressure.
Field Screening in Low-Temperature-Grown GaAs Photoconductive Antennas
Authors: Siebert Karsten J. , Lisauskas Alvydas , Löffler Torsten , Roskos Hartmut G.
Published: February 2005

This paper investigates the nature of the signals obtained in double-pulse-excitation THz-emission experiments performed on terahertz antennas with low-temperature-grown GaAs as photoconductive material. Results of such measurements on devices containing photoconductive gaps with an area below 100 µm2 have been interpreted in the past as evidence for screening effects by space charge build-up. We argue that this interpretation leads to discrepancies with what is known about charge-carrier dynamics. In analogy to the much-better-studied response of large-area emitters (photoconductors with an active area on the order of a square centimeter), we argue that radiation-field screening must be considered when interpreting the data of small-area emitters.
Electrical Properties of Melt-Epitaxy-Grown InAs0.04Sb0.96 Layers with Cutoff Wavelength of 12 µm
Authors: Gao Yu Zhu , Gong Xiu Ying , Gui Yong Sheng , Yamaguchi Tomuo , Dai Ning
Published: February 2005

A study of the electrical properties of melt epitaxy (ME)-grown InAs0.04Sb0.96/InAs epilayers with a cutoff wavelength of 12 µm was performed. From the measured temperature dependence of the electrical properties, a peak electron mobility of 100,000 cm2/V·s with a carrier density of 1×1015 cm-3 at 200 K, and an electron mobility of 60000 cm2/V·s with a carrier density of 2.3×1016 cm-3 at 300 K have been obtained for the first time. The different behaviors of the electrical properties were observed for samples grown using graphite and fused-silicon boats, and were analyzed in terms of their scattering mechanism. The results showed that ionized impurity scattering is the dominant process at low temperatures for all the samples. Polar optical phonon scattering governs electron mobility at high temperature. C contamination has significant influence on the electron mobility below 200 K for the sample grown using a graphite boat.
Thermal Properties for Hot-Pressed n-type (Bi1-xSbx)2Te3 Alloys
Authors: Im Hee-Joong , Kim Dong-Hwan , Mitani T. , Je Koo-Chul
Published: February 2005

We have measured the thermal properties of an n-type hot-pressed Bi1.8Sb0.2Te3 alloy with a carrier concentration of 3.1×1019 cm-3. With the adjustable parameters determined from these experimental data, the dependence of thermal properties on the carrier concentrations is investigated, using the two-band-conduction model with a mixed scattering mechanism and a small fluctuation theory. The maximum dimensionless figures of merit of the alloy in a carrier concentration range of 0.8–3×1019 cm-3 have values over 0.7 at temperatures between 250 K and 300 K and a minimum thermal conductivity of 1 W/Km. These alloys are comparable to single crystals, showing the possibility that they provide higher thermoelectric performance than the single crystals, since their microstructure can be controlled by hot-press processing.
An Unusual Effect of Liquid Crystal Host on the Absorption Properties of “Guest–Host” Mixture
Authors: Chigrinov Vladimir , Prudnikova Elena , Ng Kwan Wah , Drushlyak Alexander , Kwok Hoi Sing
Published: February 2005

We have observed for the first time the effects of considerable changes in the order parameter and the wavelength shift of the maximum absorption in the “guest-host” mixture of liquid crystal (“host”) with dichroic dye (“guest”) under UV-light illumination, dependent on the liquid crystal host.