bluuebunny/crossref_metadata_2025 huggingface dataset:
High-temperature annealing and optical activation of Eu-implanted GaN
Authors: Lorenz K. , Wahl U. , Alves E. , Dalmasso S. , Martin R. W. , O'Donnell K. P. , Ruffenach S. , Briot O.
Published: October 2004

Europium was implanted into GaN through a 10nm thick epitaxially grown AlN layer that protects the GaN surface during the implantation and also serves as a capping layer during the subsequent furnace annealing. Employing this AlN layer prevents the formation of an amorphous surface layer during the implantation. Furthermore, no dissociation of the crystal was observed by Rutherford backscattering and channeling measurements for annealing temperatures up to 1300°C. Remarkably, the intensity of the Eu related luminescence, as measured by cathodoluminescence at room temperature, increases by one order of magnitude within the studied annealing range between 1100 and 1300°C.
Biological sensors based on Brownian relaxation of magnetic nanoparticles
Authors: Chung S. H. , Hoffmann A. , Bader S. D. , Liu C. , Kay B. , Makowski L. , Chen L.
Published: October 2004

We experimentally demonstrate a biomagnetic sensor scheme based on Brownian relaxation of magnetic nanoparticles suspended in liquids. The characteristic time scale of the Brownian relaxation can be determined directly by ac susceptibility measurements as a function of frequency. The peak in the imaginary part of the ac susceptibility shifts to lower frequencies upon binding the target molecules to the magnetic nanoparticles. The frequency shift is consistent with an increase of the hydrodynamic radius corresponding to the size of the target molecule.
Electron capture cross sections of InAs∕GaAs quantum dots
Authors: Engström O. , Kaniewska M. , Fu Y. , Piscator J. , Malmkvist M.
Published: October 2004

By measuring the thermal emission rates of electrons from InAs∕GaAs quantum dots, capture cross sections in the extremely high region of 10−11–10−10cm2 have been found. These data have been confirmed by using an additional method based on a static measurement at thermal equilibrium, where the Fermi level is positioned at the free energy level of the quantum dot s shell.
Effects of hydrogen annealing on heteroepitaxial-Ge layers on Si: Surface roughness and electrical quality
Authors: Nayfeh Ammar , Chui Chi On , Saraswat Krishna C. , Yonehara Takao
Published: October 2004

We have studied the effect of hydrogen annealing on the surface roughness of germanium (Ge) layers grown by chemical vapor deposition on silicon using atomic force microscopy and cross-sectional high resolution scanning electron microscopy (HR-SEM). Our results indicate a strong reduction of roughness that approaches 90% at 825°C. The smoother Ge surface allowed for the fabrication of metal-oxide-semiconductor capacitors using germanium oxynitride (GeOxNy) as the gate dielectric. Electrical quality was studied using high frequency capacitance–voltage characteristic of epi-Ge showing negligible hysteresis. We discuss the results in terms of Ge–H cluster formation, which lowers the diffusion barrier, allowing for higher diffusivity and surface mobility. The temperature dependence shows tapering off for temperatures exceeding 800°C, indicating a barrier reduction of ∼92meV.
Electromagnetic needles with submicron pole tip radii for nanomanipulation of biomolecules and living cells
Authors: Matthews Benjamin D. , LaVan David A. , Overby Darryl R. , Karavitis John , Ingber Donald E.
Published: October 2004

We describe the design and fabrication of a temperature-controlled electromagnetic microneedle (EMN) to generate custom magnetic field gradients for biomedical and biophysical applications. An electropolishing technique was developed to sharpen the EMN pole tip to any desired radius between 100 nm and 20 μm. The EMN can be used to apply strong static or dynamic forces (>50nN) to micrometer- or nanometer-sized magnetic beads without producing significant heating or needle movement. Large tip radii (20 μm) allow magnetic force application to multiple magnetic beads over a large area, while small radii (0.1–6 μm) can be used to selectively pull or capture single magnetic beads from within a large population of similar particles. The customizable EMN is thus well suited for micro- and nanomanipulation of magnetic particles linked to biomolecules or living cells.
Thin biaxially textured TiN films on amorphous substrates prepared by ion-beam assisted pulsed laser deposition
Authors: Hühne R. , Fähler S. , Holzapfel B.
Published: October 2004

Thin TiN films have been grown using reactive ion-beam assisted pulsed laser deposition. The texture development was in situ analyzed using reflection high-energy electron diffraction. Above 300°C a sharp cube textured nucleation layer is observed using an ion beam with energies above 400eV under an angle of 45° relative to the substrate normal. The cube texture is not stable during further ion-beam assisted growth but can be preserved using homoepitaxial growth. Resulting films showed an in-plane orientation of about 13°. The texture development can be described in terms of energy considerations and anisotropic sputter rates.
Change of the emission spectra in organic light-emitting diodes by layer thickness modification
Authors: Cheung C. H. , Djurišić A. B. , Kwong C. Y. , Tam H. L. , Cheah K. W. , Liu Z. T. , Chan W. K. , Chui P. C. , Chan J. , Rakić A. D.
Published: October 2004

Electroluminescence and photoluminescence of organic light-emitting diodes consisting of an indium tin oxide anode, N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine as a hole transport layer, tris (8-hydroxyquinoline) aluminum as emitting layer, and an Ag cathode were measured for different layer thickness values. It was found that, for a certain range of thickness values, multiple peak emission can be achieved. In addition, the emission spectra were dependent on the viewing angle. For the optimized thickness values, normal incidence chromaticity coordinates achieved were 0.32 and 0.43. Possible explanations for observed unexpected behavior are discussed.
Domain wall diodes in ferromagnetic planar nanowires
Authors: Allwood D. A. , Xiong Gang , Cowburn R. P.
Published: October 2004

We demonstrate a lithographically defined magnetic structure through which domain walls from planar magnetic nanowires propagate in one direction only, under an appropriate magnetic field. This domain wall diode is of the form of an isosceles triangle, with one nanowire emanating from its apex and one from its base. A domain wall arriving at the triangle apex, under an applied magnetic field, is able to overcome minor pinning through the diode and continue through the opposite nanowire. However, a domain wall arriving at the triangle base is unable to overcome the significant pinning energy presented by the sudden change in track width. Domain wall diodes are of potential use in controlling domain wall propagation for fundamental investigations and technological applications.
Microlens reflector for out-of-plane optical coupling of a waveguide to a buried silicon photodiode
Authors: Nathan Menachem
Published: October 2004

A photoresist microlens is shown to be an extremely efficient reflective element for out-of-plane coupling of light from a negative epoxy-based photoresist (SU8) optical waveguide into a buried silicon pn photodetector. Experimentally determined coupling efficiencies are given for integrated waveguide∕photodetector and waveguide∕microlens∕photodetector structures. The highest measured coupling efficiency in a structure with a 40μm diameter, 13μm high microlens is about 74%, versus an average of about 11% in structures without a microlens. The measured microlens-mediated coupling efficiency is in satisfactory agreement with a simple ray tracing simulation that provides a calculated value of 77.5% for the coupling efficiency.
Phase transition dynamics measurements in superheated liquids by monitoring the ejection of nanometer-thick films
Authors: Lang Florian , Leiderer Paul , Georgiou Savas
Published: October 2004

The ejection dynamics of nanometer-thick liquid (isopropanol) films from a substrate caused by a phase transition in a superheated layer at the interface are studied. A nanosecond laser pulse is used to heat the substrate and as a result of heat transfer the fluid adjacent to the surface partially reaches a metastable state. Reflectivity and scattered light measurements demonstrate that the liquid is ejected as an intact layer which redeposits on the time scale of a few hundred nanoseconds. Measurements of the ejection dynamics are shown to be a sensitive method to obtain information about the phase transition, such as the relevant time scales and the generated pressure.
Planar thin film YBa2Cu3O7−δ Josephson junction pairs and arrays via nanolithography and ion damage
Authors: Chen Ke , Cybart Shane A. , Dynes R. C.
Published: October 2004

We have fabricated in-plane high-Tc Josephson junction pairs and series arrays using our established nanolithography and ion damage process. Junctions in a pair showed nearly identical electrical properties. The ten-junction array exhibited current–voltage characteristics that can be described by the resistively shunted junction model at 78K. Flat giant Shapiro steps were observed in both cases. We believe that the ion-damaged high-Tc superconducting Josephson junction is a good candidate to form large numbers of junctions in series arrays that can function above 77K for quantum voltage standards and other applications.
Radiation of spin waves by a single micrometer-sized magnetic element
Authors: Demidov Vladislav E. , Demokritov Sergej O. , Hillebrands Burkard , Laufenberg Markus , Freitas Paulo P.
Published: October 2004

Dynamic magnetic properties of a single micrometer-sized magnetic element consisting of a permalloy and a partially patterned CoFe layer separated by an intervening Cu spacer layer have been studied by means of a micro-focus Brillouin light scattering setup, which allows for local measurements of the magnetization dynamics on the submicrometer scale. It is shown that quantized spin-wave modes excited in the magnetic element act as radiation sources for spin waves in the surrounding magnetic film. It is found that the intensities of spin waves excited by different quantized modes follow different distance laws when traveling away from the region of excitation.
Channel waveguide lasers in a lead silicate glass fashionedusing the extrusion technique
Authors: Mairaj Arshad K. , Feng Xian , Shepherd David P. , Hewak Daniel W.
Published: October 2004

We report the use of extrusion for the development of planar buried channel waveguide lasers in a neodymium-doped lead-silicate glass host. The extrusion process was performed at a constant die temperature of 555±10°C, an applied pressure of 1850Ncm−2 and a viscosity of 107.8–107.2P, respectively. A planar substrate, 10mm in length cut from the extruded product, had four buried waveguides each with a core size of 8 by 2.5μm in the horizontal and vertical directions. Optical characterization of this waveguide revealed single-mode laser operation at 1058nm with a slope efficiency of 40% for an absorbed power of 59.3mW. The measured device propagation loss was ∼0.3dBcm−1.
Enhanced generation of fast protons from a polymer-coated metal foil by a femtosecond intense laser field
Authors: Kishimura Hiroaki , Morishita Hiroto , Okano Yasuhisa H. , Okano Yasuaki , Hironaka Yoichiro , Kondo Ken-ichi , Nakamura Kazutaka G. , Oishi Yuji , Nemoto Koshichi
Published: October 2004

The results of generation of fast protons from 5-μm-thick copper foil targets by 60fs laser irradiation at 1.5×1017W∕cm2 are presented. Both polyvinylmethylether (PVME)-coated and uncoated copper foil targets are examined. Fast protons are measured using a Thomson mass spectrometer and maximum proton energies are 570 and 280keV for the PVME-coated and the uncoated target, respectively. The intensity of fast protons with energy of 160keV from the PVME-coated target is approximately 80-fold higher than that from the uncoated target.
Fabrication of high-resolution zone plates with wideband extreme-ultraviolet holography
Authors: Solak Harun H. , David Christian , Gobrecht Jens
Published: October 2004

We report an achromatic holographic method to fabricate high-resolution x-ray optics using coherent extreme-ultraviolet radiation from an undulator source. The interference pattern between two spherical beams, which are created using Fresnel zone plates, is recorded to produce a higher-resolution zone plate. Analytical and simulation results showing the formation of the zone plate pattern was confirmed experimentally with the production and testing of a lens with 60-nm outermost zone width. The combination of extreme-ultraviolet light, which exposes photoresists with practically no proximity effect, and holography, which guarantees the accurate placement of zones, addresses the main difficulties faced in the improvement of the resolution of x-ray lenses. Holography with extreme-ultraviolet light has the potential to produce lenses with sub-10-nm resolution.
Origins of luminescence from nitrogen-ion-implanted epitaxial GaAs
Authors: Weng X. , Goldman R. S. , Rotberg V. , Bataiev N. , Brillson L. J.
Published: October 2004

We have examined the origins of luminescence in N-ion-implanted epitaxial GaAs, using a combination of cross-sectional transmission electron microscopy and low-energy electron-excited nanoscale-luminescence spectroscopy. A comparison of reference, as-implanted, and implanted-plus-annealed samples reveals a variety of emissions. In all samples, we observe the GaAs fundamental band-gap emission, as well as several emissions related to GaAs native defects. In the as-implanted and implanted-plus-annealed samples, an emission related to the implantation-induced defects, is also observed. Interestingly, in the implanted-plus-annealed samples, we identify a near-infrared emission associated with GaAsN nanocrystallites.
Positional control of self-assembled quantum dots by patterning nanoscale SiN islands
Authors: Gotoh H. , Kamada H. , Saitoh T. , Shigemori S. , Temmyo J.
Published: October 2004

We propose a method for obtaining position-controlled self-assembled quantum dots. The self-assembled InGaAs quantum dots are grown on a GaAs (311) B substrate on which SiN islands have been patterned using a nanolithographic technique. The SiN pattern determines the position of the quantum dots as well as their optical properties. The positional uniformity and photoluminescence spectrum strongly depend on the pitch of the SiN pattern. At an optimum pitch, uniformly arranged quantum dots and intense photoluminescence spectra with sharp peaks are obtained.
High friction of a vertically aligned carbon-nanotube film in microtribology
Authors: Kinoshita Hiroshi , Kume Ippei , Tagawa Masahito , Ohmae Nobuo
Published: October 2004

The frictional behavior of a vertically aligned carbon-nanotube (VACNT) film against gold tips was studied in air. In these experiments, the film was 6 μm thick, the tip radii 4.5–30 μm, the applied forces smaller than 5 μN, and speeds were 0.15–24 μm/s. In spite of the null adhesion force to the gold tip, extremely high friction coefficients of 1.0–2.2 were found for the VACNT film. No dependence of friction on speed or tip radius was observed.
Molecular beam epitaxial growth and characterization of zinc-blende ZnMgSe on InP (001)
Authors: Sohel Mohammad , Muñoz Martin , Tamargo Maria C.
Published: October 2004

High crystalline quality zinc-blende structure Zn(1−x)MgxSe epitaxial layers were grown on InP (001) substrates by molecular beam epitaxy. Their band gap energies were determined as a function of Mg concentration and a linear dependence was observed. The band gap of the Zn(1−x)MgxSe closely lattice matched to InP was found to be 3.59 eV at 77 K and the extrapolated value for zinc-blende MgSe was determined to be 3.74 eV. Quantum wells of Zn(1−x)CdxSe with Zn(1−x)MgxSe as the barrier layer were grown which exhibit near ultraviolet emission.
MgB
2
films with very high critical current densities due to strong grain boundary pinning
Authors: Kitaguchi H. , Matsumoto A. , Kumakura H. , Doi T. , Yamamoto H. , Saitoh K. , Sosiati H. , Hata S.
Published: October 2004

MgB 2 superconductor has a great potential for applications because of its high Tc and Bc2, exceeding those of any Nb-base superconductors at any temperature. It is now important to understand its flux pinning so as to raise Jc to high values over a wide field range. We show that nanometer-sized columnar-grain structure can produce Jc exceeding 5×106A∕cm2. The angular dependence of Jc indicates that the strongest pinning occurs when the field is aligned parallel to the grain boundaries. Our results confirm earlier deductions that grain boundaries in MgB2 act as effective pinning centers like those in Nb3Sn.
High-reflectivity Pd∕Ni∕Al∕Ti∕Au ohmic contacts to p-type GaN for ultraviolet light-emitting diodes
Authors: Chen Guan-Ting , Pan Chang-Chi , Fang Chi-Shin , Huang Tzu-Chien , Chyi Jen-Inn , Chang Mao-Nan , Huang Sheng-Bang , Hsu Jung-Tsung
Published: October 2004

Thermal stability, optical reflectivity, and contact resistivity of Pd∕Ni∕Al∕Ti∕Au ohmic contacts to p-type GaN were investigated. In contrast to its Pd∕Al∕Ti∕Au counterparts, Pd∕Ni∕Al∕Ti∕Au contacts retained their specific contact resistivity (<2×10−2Ωcm2) and reflectivity (>76%) after long-term annealing at 150 °C in nitrogen ambient. According to the results of the secondary ion mass spectroscopy study, it is suggested that the Ni layer prevents the penetration of Ti into GaN during thermal treatment.
Preserving properties of object shape by computations in primary visual cortex
Authors: Stevens Charles F.
Published: October 2004

Although our visual system is extremely good at extracting objects from the visual scene, this process involves complicated computations that are thought to require image processing by many successive cortical areas. Thus, intermediate stages in object extraction should not eliminate essential properties of the objects that are still required by later stages. A particularly important characteristic of an object is its shape, and shape has the property that it is unchanged by translations, rotations, and magnifications of the image. I show that the requirement for this property of shape to be preserved in the image, as represented by the firing of neurons in the primary visual cortex (V1), is equivalent to a particular type of computation, known as a wavelet transform, determining the firing rate of V1 neurons in response to an image on the retina. Experimental data support the conclusion that the neural representation of images in V1 is described by a wavelet transform and, therefore, that the properties of shape are preserved.
Dysregulation of the fibroblast growth factor system in major depression
Authors: Evans S. J. , Choudary P. V. , Neal C. R. , Li J. Z. , Vawter M. P. , Tomita H. , Lopez J. F. , Thompson R. C. , Meng F. , Stead J. D. , Walsh D. M. , Myers R. M. , Bunney W. E. , Watson S. J. , Jones E. G. , Akil H.
Published: October 2004

In this report we describe findings that imply dysregulation of several fibroblast growth factor (FGF) system transcripts in frontal cortical regions of brains from human subjects with major depressive disorder (MDD). This altered gene expression was discovered by microarray analysis of frontal cortical tissue from MDD, bipolar, and nonpsychiatric control subjects and was verified by quantitative real-time PCR analysis and, importantly, in a separate cohort of MDD subjects. Furthermore, we show, through a separate analysis of specific serotonin reuptake inhibitor (SSRI)-treated and non-SSRI-treated MDD subjects that the observed changes in expression of FGF transcripts are not secondary to drug treatment. Rather, changes in specific FGF transcripts are attenuated by SSRIs and may thus be partially responsible for the mechanism of action of these drugs. We also make available the gene-expression profile of all of the other growth factors and growth factor receptors detected in these postmortem samples.
Nutritional requirements of surgical and critically-ill patients: do we really know what they need?
Authors: Reid Clare L.
Published: October 2004

Malnutrition remains a problem in surgical and critically-ill patients. In surgical patients the incidence of malnutrition ranges from 9 to 44%. Despite this variability there is a consensus that malnutrition worsens during hospital stay. In the intensive care unit (ICU), 43% of the patients are malnourished. Although poor nutrition during hospitalisation may be attributable to many factors, not least inadequacies in hospital catering services, there must also be the question of whether those patients who receive nutritional support are being fed appropriately. Indirect calorimetry is the ‘gold standard’ for determining an individual's energy requirements, but limited time and financial resources preclude the use of this method in everyday clinical practice. Studies in surgical and ICU patient populations have been reviewed to determine the ‘optimal’ energy and protein requirements of these patients. There are only a small number of studies that have attempted to measure energy requirements in the various surgical patient groups. Uncomplicated surgery has been associated with energy requirements of 1·0–1·15×BMR whilst complicated surgery requires 1·25–1·4×BMR in order to meet the patient's needs. Identifying the optimal requirements of ICU patients is far more difficult because of the heterogeneous nature of this population. In general, 5·6 kJ (25 kcal)/kg per d is an acceptable and achievable target intake, but patients with sepsis or trauma may require almost twice as much energy during the acute phase of their illness. The implications of failing to meet and exceeding the requirements of critically-ill patients are also reviewed.
Timing of nutrient restriction and programming of fetal adipose tissue development
Authors: Symonds Michael E. , Pearce Sarah , Bispham Jayson , Gardner David S. , Stephenson Terence
Published: October 2004

It is apparent from epidemiological studies that the timing of maternal nutrient restriction has a major influence on outcome in terms of predisposing the resulting offspring to adult obesity. The present review will consider the extent to which maternal age, parity and nutritional restriction at defined stages of gestation can have important effects on fat deposition and endocrine sensitivity of adipose tissue in the offspring. For example, in 1-year-old sheep the offspring of juvenile mothers have substantially reduced fat deposition compared with those born to adult mothers. Offspring of primiparous adult mothers, however, show increased adiposity compared with those born to multiparous mothers. These offspring of multiparous ewes show retained abundance of the brown adipose tissue-specific uncoupling protein 1 at 1 month of age. A stimulated rate of metabolism in brown fat of these offspring may act to reduce adipose tissue deposition in later life. In terms of defined windows of development that can programme adipose tissue growth, maternal nutrient restriction targetted over the period of maximal placental growth results in increased adiposity at term in conjunction with enhanced abundance of mRNA for the insulin-like growth factor-I and -II receptors. In contrast, nutrient restriction in late gestation, coincident with the period of maximal fetal growth, has no major effect on adiposity but results in greater abundance of specific mitochondrial proteins, i.e. voltage-dependent anion channel and/or uncoupling protein 2. These adaptations may increase the predisposal of these offspring to adult obesity. Increasing maternal nutrition in late gestation, however, can result in proportionately less fetal adipose tissue deposition in conjunction with enhanced abundance of uncoupling protein 1.
Appetite regulation and seasonality: implications for obesity
Authors: Adam Clare L. , Mercer Julian G.
Published: October 2004

High circulating concentrations of leptin in obesity are associated with an apparent loss of its characteristic anorexic action within the hypothalamic region of the brain. Central insensitivity to leptin may therefore contribute to the aetiology of this disease, and an increased understanding of the underlying mechanisms will identify potential means of prevention and/or therapeutic targets. Seasonal animals such as sheep and Siberian hamsters (Phodopus sungorus) exhibit annual photoperiod-driven cycles of appetite and body weight. Increased food intake and weight gain in long days (summer) are associated with high circulating leptin, and decreased intake and weight loss in short days (winter) with low leptin. Critically, these cycles are associated with reversible changes in sensitivity to leptin. High sensitivity is seen in short days and relative insensitivity in long days, demonstrated both in sheep given leptin centrally via intracerebroventricular cannulas and in hamsters given leptin peripherally. In addition, primary hypothalamic appetite-regulating targets for leptin (i.e. neuropeptide Y, melanocortin and cocaine- and amphetamine-regulated transcript pathways) respond differently in these species to changes in circulating leptin and nutritional status induced by photoperiod as opposed to such changes induced by food restriction. Studies of seasonal animals will help to resolve causes of altered sensitivity to leptin and whether these changes reflect altered transport into the brain and/or altered signalling at the receptor or post-receptor level. Increased knowledge of the mechanism(s) and time-course for development and reversal of reduced central leptin sensitivity will provide new insights into the development and control of obesity.
Diet, genes and disease: implications for nutrition policy
Authors: Gibney Michael J. , Gibney Eileen R.
Published: October 2004

There is extensive evidence to show that there is considerable variation in diet and disease patterns in Europe and that many of the dietary patterns are predictive of chronic disease. Increasingly, there is evidence that this dietary effect is mediated by genetic background. The present paper examines the role of polymorphisms within three genes, those responsible for the synthesis of apoE, 5,10-methylenetetrahydrofolate reductase (MTHFR) and PPARγ. There is clear evidence to support the concept that the diet–disease link is moderated by genetic variation. The paper then considers whether this moderating effect will have implications for dietary recommendations. In the formulation of dietary reference values it has long been recognized that these values cannot cover the needs of all individuals. By setting the upper level at the mean value +2 sd, the needs of 97·5% of the population are covered. Setting a hypothetical scenario of a nutrient requirement of 200 mg\d and a polymorphism with an allelic frequency in the general population in the range of 0, 10, 20 and 30% that causes an increased nutrient requirement of 25%, there was no evidence that the traditional approach requires revision. Whilst it is recognized that genetic variability may not influence population goals, genetic variability will have to be taken into account in the clinical nutrition management of disease. To knowingly assign a patient to life-long treatment with a diet that for genetic reasons will have no success is both unethical and uneconomical. Once accepted in clinical nutrition, the diet–gene interaction will filter into the prevention of disease in public health nutrition.
Prenatal programming of postnatal obesity: fetal nutrition and the regulation of leptin synthesis and secretion before birth
Authors: McMillen I. C. , Muhlhausler B. S. , Duffield J. A. , Yuen B. S. J.
Published: October 2004

Exposure to either an increased or decreased level of intrauterine nutrition can result in an increase in adiposity and in circulating leptin concentrations in later life. In animals such as the sheep and pig in which fat is deposited before birth, leptin is synthesised in fetal adipose tissue and is present in the fetal circulation throughout late gestation. In the sheep a moderate increase or decrease in the level of maternal nutrition does not alter fetal plasma leptin concentrations, but there is evidence that chronic fetal hyperglycaemia and hyperinsulinaemia increase fetal fat mass and leptin synthesis within fetal fat depots. Importantly, there is a positive relationship between the relative mass of the ‘unilocular’ component of fetal perirenal and interscapular adipose tissue and circulating fetal leptin concentrations in the sheep. Thus, as in the neonate and adult, circulating leptin concentrations may be a signal of fat mass in fetal life. There is also evidence that leptin can act to regulate the lipid storage, leptin synthetic capacity and potential thermogenic functions of fat before birth. Thus, leptin may act as a signal of energy supply and have a ‘lipostatic’ role before birth. Future studies are clearly required to determine whether the intrauterine and early postnatal nutrient environment programme the endocrine feedback loop between adipose tissue and the central and peripheral neuroendocrine systems that regulate energy balance, resulting in an enhanced risk of obesity in adult life.
Prenatal programming of postnatal obesity: fetal nutrition and the regulation of leptin synthesis and secretion before birth
Authors: Davidson Isobel , Smith Sara
Published: October 2004

The introduction of the process of nutritional screening into clinical standards has been driven by the increasing awareness of the prevalence of undernutrition in acute and primary care, along with its associated morbidity and mortality. However, the increasing prevalence of obesity in the general population suggests that an increased number of patients admitted to hospital will be obese. Increased morbidity has also been reported in the injured obese patient and may be associated with poor nutritional support. This situation may occur because the profound metabolic disturbances accompanying trauma in this group are not recognised, and subsequent feeding practices are inappropriate. Screening tools currently classify patients by using simple markers of assessment at the whole-body level, such as BMI. Subsequently, patients are identified as at risk only if they are undernourished. Such comparisons would by definition classify injured obese patients as at minimal or no nutritional risk, and they would therefore be less likely to be re-screened. This approach could result in potential increases in morbidity, length of rehabilitation and consequent length of hospital stay. It is likely that the identification of potential risk in obese injured patients goes beyond the measurement of such indices as BMI and percentage weight loss, which are currently utilised by the majority of screening processes.
Food for life, love and hope: an exemplar of the philosophy of palliative care in action
Authors: Hopkins Katherine
Published: October 2004

The World Health Organization's (1990) definition of palliative care describes an holistic approach to care for patients with advanced progressive illness. Issues relating to nutrition, lack of appetite and the subsequent weight loss the individuals may experience present a challenge to all concerned with providing both formal and informal care to this patient group. The philosophy of palliative care requires a multidisciplinary approach to the constellation of issues and problems related to food that are faced by both patients and carers in receipt of palliative care. The literature in this area is mainly related to those patients with a cancer diagnosis. The developing role of palliative care in patients with non-malignant disease provides further challenges for health care professionals. The present paper aims to reflect an entire philosophical approach to care through an examination of one area of practice.
Chronic idiopathic intestinal pseudo-obstruction: the need for a multidisciplinary approach to management
Authors: Silk D. B. A.
Published: October 2004

At the outset of the research programme into irritable bowel syndrome (IBS) it was perceived that there was a need to develop a symptom-based classification for the patients. Four groups of patients were identified, those with spastic colon syndrome, diarrhoea-predominant spastic colon syndrome, functional diarrhoea and midgut dysmotility. While working with outpatients with IBS it was noted how some of them had suffered symptoms for many years; specifically, a group of patients satisfying the criteria for midgut dysmotility had also suffered from particularly severe and intractable intestinal symptoms. These patients underwent 24 h ambulatory studies of small intestinal motility and the majority were found to have manometric features of chronic idiopathic intestinal pseudo-obstruction (CIIP). To characterise the cause, laparoscopic full-thickness small intestine and colonic biopsies have been obtained in forty-five of the latter group of patients. Of these patients 58% have been found to have complete or partial deficiency of α-actin epitope staining in the inner circular layer of small intestinal smooth muscle. This deficiency is believed to represent an important biomarker rather than the cause of CIIP, since α-actin epitope deficiency has been observed in association with enteric neuropathy and myopathies. In relation to the management of CIIP patients, a multidisciplinary model is proposed incorporating management of co-morbid psychological and psychiatric pathology, abdominal and musculoskeletal pain, fatigue, urological symptoms and nutrition. A six-stage nutritional management plan for these patients is presented.
Nutritional support in patients with advanced cancer: permission to fall out?
Authors: McKinlay A. W.
Published: October 2004

Data from the European Society for Parenteral and Enteral Nutrition Home Artificial Nutrition Survey suggest that the use of home parenteral nutrition (HPN) in patients with cancer as the primary diagnosis varies markedly between different countries in Europe, being highest in The Netherlands and low in the UK. This finding is difficult to explain on the basis of cancer incidence. The main indication for HPN remains malignant gastrointestinal tract obstruction, which occurs most frequently in gynaecological and colon cancers. The use of HPN should be planned in the light of the proposed cancer treatment and should be discussed beforehand with the patient. Before HPN is considered, a patient should typically require intravenous fluids to maintain hydration, be capable of self care, be able to control the treatment, have an expected survival of ≥3 months and have no other available route of feeding. The effect of HPN on quality of life remains controversial, but nutrition is only one of the factors that influence the quality of life in cancer patients. The differing rates of HPN in Europe are probably related to cultural attitudes to incurable cancer as much as to meeting the nutritional needs of the patient.
Optimal nutritional support
Authors: Woodcock Nicholas , MacFie John
Published: October 2004

There is ongoing debate about the respective roles of enteral and parenteral nutrition. The present short review suggests that these two feeding modalities are not mutually exclusive and that optimal nutritional support may necessitate the concomitant administration of enteral together with parenteral nutrition.
Molecular cloning and characterization of an endo-β-mannanase gene expressed in the lettuce endosperm following radicle emergence
Authors: Wang Aoxue , Li Jieran , Bewley J. Derek
Published: October 2004

Endo-β-mannanase (EC 3.2.1.78), an enzyme that mobilizes the endosperm cell walls of the lettuce (Lactuca sativa L.) seed, increases in activity in the micropylar and lateral regions of this tissue following the completion of germination. Its complementary DNA (cDNA) sequence (LsMan1) was determined using the polymerase chain reaction (PCR) with degenerate primers. The 3‘-end of the cDNA sequence was obtained by 3‘-end rapid amplification of cDNA ends (RACE), and the 5‘-end sequence by genome walking and 5‘-end RACE. The predicted amino acid sequence from the cDNA has a high identity with endo-β-mannanases present in other species (e.g. 67% identity with coffee β-1,4-mannan endohydrolase, 62% identity with tomato fruit endo-β-mannanase). Southern blot analysis suggests the presence of several members of an endo-β-mannanase gene family in the lettuce genome. Several isoforms of the enzyme, including three major ones, were detected by isoelectric focusing. Based on Northern blot analysis, accumulation of the endo-β-mannanase mRNA occurred only after lettuce seeds had germinated, and increased thereafter, although enzyme activity persisted after transcription declined.
Protein phosphorylation is suppressed when wheat embryos are hydrated and remain growth arrested
Authors: Wagner Ryan L. , Walker-Simmons M.K.
Published: October 2004

An early difference in net protein phosphorylation activity occurred in dormant and after-ripened wheat (Triticum aestivumL.) grains within the first hour of imbibition at 30°C. Embryos from dry, dormant and after-ripened caryopses exhibited a high degree of protein phosphorylation, particularly of four proteins (68, 54, 51 and 42 kDa). Upon hydration, protein phosphorylation activity in dormant embryos decreased within 1 h and reached minimal phosphorylation activity by 5 h. Protein phosphorylation activity in after-ripened (germinable) embryos was not suppressed and remained high during germination. If the hydrated dormant embryos were dried, protein phosphorylation activity was restored. Application of the protein phosphatase inhibitor, okadaic acid, partially overcame dormancy and slowed the decrease in phosphorylation activity. These results suggested that reduction of protein phosphorylation activity slowed the rate of germination.
From what depth do seeds emerge? A soil seed bank experiment with Mediterranean grassland species
Authors: Traba Juan , Azcárate Francisco M. , Peco Begoña
Published: October 2004

Seed germination and emergence are influenced by the position of seeds in the soil bank profile. Mediterranean grasslands are heavily dependent on seed banks, as these systems are mainly composed of annual species. Seed bank germination experiments in a greenhouse were conducted to analyse the role played by burial depth on seed bank dynamics in annual Mediterranean grasslands. Specifically, they addressed two objectives: (1) to assess the ability of seeds in the shallow layer of the soil bank to emerge when they are buried at different depths, and (2) to ascertain the ability of seeds from deep layers to germinate and emerge to the surface. The study also produced a depth profile of species and seeds. The results show that: (1) all species (100%) and the majority of viable seeds (98.9%) are situated in the first centimetre, with a significant fall in the number of species and seeds in the soil bank as depth increases; (2) for the majority of species (92%) and seeds (85.4%) in the shallow bank, the emergence percentage declines significantly with burial depth; and (3) seeds that are present in deep layers need to rise to the surface in order to produce seedlings. In conclusion, the function of the seed bank in Mediterranean grasslands depends on the number of species and seeds in it, but also on the seed position in the profile and vertical movements that enable them to reach the surface.
Germination and seed bank depletion of holly (Ilex aquifolium L.) in four microhabitat types
Authors: Arrieta Sagrario , Suárez Francisco
Published: October 2004

The germination dynamics ofIlex aquifoliumL. were studied in central Spain using a 3-year field sowing experiment. Ten triads of bags (n= 30 seeds per bag) were buried randomly in four different microhabitats: inside the holly woodland, along the forest edge, in open grassland and under isolated shrubs. Bags were harvested annually, and seeds were analysed for seed viability, embryo development changes and germination. Holly seeds did not germinate until the second year. Embryo development and seed germination were faster at the forest edge, with a total germination proportion of 63% of sown seeds. Germination in the holly woodland (48%), under the shrubs (46%) and in grassland (46%) were very similar. Thus, recruitment ofIlexpopulations in this region is not limited by requirements for germination. After the third year, the seed bank was reduced by 80–90% of the initial seeds, so it can be considered as a short-persistent seed bank. Holly seed behaviour can enhance recruitment in semi-open areas, such as forest edges. Linked to the short persistence of its seed bank, this species can be considered an intermediate strategist between mature forest specialists and early successional species. This work contributes to a deeper knowledge of the germination ecology ofI. aquifolium, in an effort to determine the relative importance of germination/ dormancy processes within holly population dynamics.
Risk factor models for adolescent verbal and physical aggression toward mothers
Authors: Pagani Linda S. , Tremblay Richard E. , Nagin Daniel , Zoccolillo Mark , Vitaro Frank , McDuff Pierre
Published: October 2004

Contributing to the family violence and conflict literature, we examine prospective and concurrent risk factors associated with verbal and physical aggression toward mothers by 15/16 year-old adolescent sons and daughters. Data from the Quebec Longitudinal Study of Kindergarten Children is used to examine the influence of socioeconomic factors, inherent individual and family environment factors, and prospective and concurrent parenting process factors as predictors of adolescent aggression (in the last 6 months). A childhood behavioural pattern characterised by physical aggression generated the highest risk of adolescent-directed verbal and physical aggression toward mothers. Aggressive parental punishment in the last 6 months significantly predicted aggression toward mothers. A childhood life-course of violence seems to culminate in verbal and physical aggression toward mothers during adolescence. Given this building-up process from childhood, harsh parental punishment of the adolescent seems to only increase the odds of adolescent aggression. No sex differences were observed.
Mental state expressions in US and Japanese children’s books
Authors: Dyer-Seymour Jennifer R. , Shatz Marilyn , Wellman Henry M. , Saito Miho T.
Published: October 2004

US children’s books are a rich source of information about mental states (Dyer, Shatz, & Wellman, 2000). Examining books from other cultures can determine whether and how such information is conveyed by other languages. Forty US and 40 Japanese picture books for preschoolers were compared. The books were coded for references to mental state via expressions in the texts. The sentential contexts of those expressions were further coded for individual or group-oriented connotations. Results revealed that mental state terms were highly frequent in both US and Japanese books. In addition, 9 of the 11 most frequent terms were the same across the two languages. Finally, the two sets of books did not differ significantly in the frequency of terms that had individual or group-oriented connotations. These findings suggest that children’s books convey not just culture-specific but universally useful information about mental states.
Change and stability in children’s social network and self-perceptions during transition from elementary to junior high school
Authors: Cantin Stéphane , Boivin Michel
Published: October 2004

This study examined the changes in children’s social network and specific self-perceptions during the transition from elementary school to junior high school (JHS). The participants were 200 preadolescent children (104 girls, 96 boys). Children’s self-perceptions (global self-worth, perceived academic competence, and perceived social acceptance) and social network characteristics (parents and peer-enacted support) were evaluated four consecutive times over a 2-year period. Despite a slight decrease in the size of children’s social network after the transition, the passage into JHS had no negative impact on the quality and functional aspects of their relationships with parents and school friends. The school transition was instead associated with an intensification of supportive relationships with school friends. Children’s perceived social acceptance also increased suddenly after the JHS transition, while children’s perceived scholastic competence decreased simultaneously during that time. Children’s general self-esteem was then observed to decline progressively over a longer period of time.
Brain Inflammation and Alzheimer's-Like Pathology in Individuals Exposed to Severe Air Pollution
Authors: Calderón-Garcidueñas Lilian , Reed William , Maronpot Robert R. , Henriquez-Roldán Carlos , Delgado-Chavez Ricardo , Calderón-Garcidueñas Ana , Dragustinovis Irma , Franco-Lira Maricela , Aragón-Flores Mariana , Solt Anna C. , Altenburg Michael , Torres-Jardón Ricardo , Swenberg James A.
Published: October 2004

Air pollution is a complex mixture of gases (e.g., ozone), particulate matter, and organic compounds present in outdoor and indoor air. Dogs exposed to severe air pollution exhibit chronic inflammation and acceleration of Alzheimer's-like pathology, suggesting that the brain is adversely affected by pollutants. We investigated whether residency in cities with high levels of air pollution is associated with human brain inflammation. Expression of cyclooxygenase-2 (COX2), an inflammatory mediator, and accumulation of the 42-amino acid form of β-amyloid (A β42), a cause of neuronal dysfunction, were measured in autopsy brain tissues of cognitively and neurologically intact lifelong residents of cities having low (n:9) or high (n:10) levels of air pollution. Genomic DNA apurinic/apyrimidinic sites, nuclear factor- κB activation and apolipoprotein E genotype were also evaluated. Residents of cities with severe air pollution had significantly higher COX2 expression in frontal cortex and hippocampus and greater neuronal and astrocytic accumulation of A β42 compared to residents in low air pollution cities. Increased COX2 expression and A β42 accumulation were also observed in the olfactory bulb. These findings suggest that exposure to severe airpollution is associated with brain inflammation and A β 42 accumulation, two causes of neuronal dysfunction that precede the appearance of neuritic plaques and neurofibrillary tangles, hallmarks of Alzheimer's disease.
Hepatic Temporal Gene Expression Profiling in Helicobacter hepaticus-Infected A/JCr Mice
Authors: Boutin Samuel R. , Rogers Arlin B. , Zeli Shen  , Fry Rebecca C. , Love Jennifer A. , Nambiar Prashant R. , Suerbaum Sebastian , Fox James G.
Published: October 2004

Helicobacter hepaticus infection of A/JCr mice is a model of infectious liver cancer. We monitored hepatic global gene expression profiles in H. hepaticus infected and control male A/JCr mice at 3 months, 6 months, and 1 year of age using an Affymetrix-based oligonucleotide microarray platform on the premise that a specific genetic expression signature at isolated time points would be indicative of disease status. Model based expression index comparisons generated by dChip yielded consistent profiles of differential gene expression for H. hepaticus infected male mice with progressive liver disease versus uninfected control mice within each age group. Linear discriminant analysis and principal component analysis allowed segregation of mice based on combined age and lesion status, or age alone. Up-regulation of putative tumor markers correlated with advancing hepatocellular dysplasia. Transcriptionally down-regulated genes in mice with liver lesions included those related to peroxisome proliferator, fatty acid, and steroid metabolism pathways. In conclusion, transcriptional profiling of hepatic genes documented gene expression signatures in the livers of H. hepaticus infected male A/JCr mice with chronic progressive hepatitis and preneoplastic liver lesions, complemented the histopathological diagnosis, and suggested molecular targets for the monitoring and intervention of disease progression prior to the onset of hepatocellular neoplasia.