bluuebunny/crossref_metadata_2025_split huggingface dataset:
Post‐prandial administration of the insulin analogue insulin aspart in patients with Type 1 diabetes mellitus
Authors: Brunner G. A. , Hirschberger S. , Sendlhofer G. , Wutte A. , Ellmerer M. , Balent B. , Schaupp L. , Krejs G. J. , Pieber T. R. 
Published: July 2002

Summary Aims In intensified insulin therapy, the recent development of short‐acting insulin analogues with a very rapid onset of action forces a new discussion in terms of the optimal injection–meal interval. This study evaluated prandial glycaemia in patients with Type 1 diabetes following the subcutaneous injection of soluble human insulin (HI) and the insulin analogue insulin aspart (IAsp) at different injection–meal intervals and investigated whether administration of IAsp after the meal might provide satisfactory metabolic control. Methods In a randomized, double‐blind, double‐dummy, four‐period crossover study, 20 Type 1 diabetic patients were investigated. Prandial insulin was administered 15 min before the start of the meal (HI(−15min)), immediately before the meal (HI(0min); IAsp(0min)) and 15 min after the start of the meal (IAsp(+15min)). Results Plasma glucose excursions from baseline levels during the 4 h (PGexc) were highest with HI(0min) (17.9 mmol.l−1.h; P < 0.05 vs. other treatments) and were not statistically different for HI(−15min), IAsp(0min) and IAsp(15min) (13.6, 11.9 and 14.2 mmol.l−1.h, respectively). Maximum concentration of plasma glucose (PGmax) was lowest with IAsp(0min) (11.2 mmol/l; P < 0.05 vs. other treatments). PGmax was comparable with HI(−15min), HI(0min) and IAsp(+15min) (13.3, 14.1 and 13.2 mmol/l, respectively). Conclusions With regard to prandial glycaemia IAsp(+15min) is as effective as HI(− 5min) and superior to HI(0min). Thus, post‐prandial dosing of the insulin analogue IAsp offers an attractive and feasible therapeutic option for well‐controlled patients with Type 1 diabetes mellitus.
The influence of boron doping on the structure and thermal decomposition of ultrathin C/B:H films
Authors: Schenk A. , Winter B. , Lutterloh C. , Biener J. , Schubert U. A. , Küppers J. 
Published: July 2002

Few monolayers thick hydrogenated carbon films doped with boron (C/B:H) were prepared and investigated in an ultrahigh-vacuum environment by high-resolution electron energy loss, Auger electron, electron energy loss, and thermal desorption/decomposition spectroscopies with specific emphasis on their chemical erosion behavior as compared to their undoped C:H counterparts. Films of thicknesses ranging from 1 to about 10 monolayers, with a maximum B/C ratio of 0.5, were grown by ion-beam deposition at room temperature on a carrier consisting of a Pt(100) single-crystal surface covered with a graphite monolayer. The process gas used was a mixture of ethane and trimethylboron of varied compositions. While at zero boron concentration the films exhibit a graphiticlike structure with about equal amounts of carbon atoms in the sp2 and sp3 hybridization state, with increasing boron concentration the film structure becomes increasingly sp3 dominated. This is evidenced by decreasing HREELS loss intensities of the vibrational modes related to graphitic hydrogenated carbon, i.e., C=C, sp2 CH stretches, and aromatic CH deformations, but enhanced C–C and sp3 CHn stretch mode intensities. No BH vibrational modes have been observed at any doping level. In accordance with these observations, the C-272 eV Auger peak line shape underwent a change characteristic for a sp3-dominated network upon B doping. The π-plasmon energy was found to shift toward lower energies at C/B:H films which also is in line with a decrease of the carbon sp2 concentration, giving further support for a change to a less graphitic structure. The observed enhanced capacity for hydrogen in the films was found to correlate in a linear fashion with the increase of the fraction of carbon atoms in the sp3 configuration. The relative hydrogen content of the films, H/C, starting at 0.4 at zero boron content, was observed to increase, saturating at 0.75 for boron concentrations greater than 10%.
This in turn coincides with a substantial growth of the film hydrogen capacity, as judged from the amount of H2 desorbing from the films between 500 and 1100 K upon thermal decomposition of the films. Although hydrogen originating from sp3 CH groups increased significantly, the amount of chemically eroded species, monitored by CnHm production in the thermal decomposition spectra, was unaffected by boron doping. However, the desorption maxima for either species, hydrogen and hydrocarbons, shift to lower temperatures at boron doped films. As reasons for the effect of B doping on the chemical constitution of C/B:H films and the resulting chemical erosion behavior, the capability of B to block the formation of aromatic structures is proposed.
Soft laser sputtering of GaAs semiconductor (100) surface
Authors: Vivet L. , Barthe M. F. , Gibert-Legrand T. , Dubreuil B. 
Published: July 2002

We have studied the soft laser sputtering of (100)GaAs with 337 nm photons, starting from the threshold for particle emission (a few tens of mJ/cm2) to some 300 mJ/cm2 fluences. Atoms and molecules sputtered from the irradiated surface are detected, their relative number measured, and their time of flight determined using laser resonant ionization mass spectrometry. The surface after laser irradiation is examined by scanning electron microscopy and electron microprobe analysis.
One observes a significant preferential emission of arsenic in the form of As2. This leads to the formation of perturbed Ga-rich surface structure which appears even at low fluence and after a few tens of laser shots on the same spot. This initial transformation seems to determine the further evolution of the irradiated surface. First, Ga atoms aggregate to form Ga islands on the surface; after a sufficient number of shots, micrometric structures are produced which finally behave as pure Ga metal. This evolution of the surface state after multipulse irradiation appears practically the same for low and medium laser fluences, the only difference being in the number of shots required to obtain the same microscopic structure. The velocity distribution of Ga atoms and As2 molecules is well fitted by half-space Maxwellian distributions. The kinetic temperatures are in broad agreement with the results obtained from a model of laser heating of the surface. The gross features of the experimental results can be interpreted from the particular thermodynamics properties of GaAs which exhibits very large As2 pressure above the solid as soon as the temperature exceeds 950 K. After a few laser shots, corresponding to particle emission from defect sites, the thermodynamics of GaAs appears to govern the further evolution of the laser-sputtered surface. Two sputtering regimes are evidenced: In the low-fluence regime (from threshold to 90 mJ/cm2) sputtering appears to be dominated by surface defect emission, whereas for higher fluences emission is more characteristic of thermal process accompanied by preferential sputtering of arsenide. According to these experimental results, a simple analytical model was developed which relates the quantitative surface to the quantitative sputtered cloud compositions.
Influence of sputter gas and sputter pressure on the structure and magnetic properties of Co–Pt–Cr thin films (abstract)
Authors: Roshko A. , Dulcie L. L. , Nguyen T. , Yogi T. 
Published: July 2002

The magnetic properties of high density recording media have been shown to be very sensitive to the film microstructure. We have investigated the influences of different sputter gases (Ar, Xe, Kr) and different sputter pressures (3 to 24 mTorr) on the microstructures and magnetic properties of CoPtCr/Cr thin films. The magnetic properties of the films (coercive field, Hc, coercive squareness, S*, and remanant moment, Mr) were determined using a vibrating sample magnetometer. The microstructures were examined by transmission electron microscopy and x-ray diffraction. For all three gases studied the microstructures and properties of the CoPtCr films were found to change with sputter pressure in similar manners. Films deposited at the lowest pressure consisted of well connected, equiaxed grains. With only a slight increase in pressure, the grains formed chains separated by small gaps. As the gas pressure increased further, the chains became better defined and the gaps between them widened. The coercive squareness and coercive field correlate with the film microstructures. S* decreased with increasing sputter gas pressure, and Hc first increased and then decreased. For all three sputter gases, Hc reached a maximum around 12 mTorr.
Likewise, S* decreased quite slowly with increasing pressure up to 12 mTorr and then exhibited a sharp drop between 12 and 18 mTorr. From these results it appears that the sputter pressure, rather than the mass of the sputter gas, is most important for the microstructural development of the film. Likewise, the values of S* were found to be independent of the sputter gas. However, in spite of the similar microstructures, films deposited with Ar had higher values of Hc than films deposited with Xe or Kr, for all sputter pressures examined. The role of the sputter gas mass will be discussed.
Colossal magnetoresistivity in manganese-based perovskites (invited) (abstract)
Authors: Ramesh R. , Venkatesan T. , Ogale S. B. , Greene R. L. , Bhagat S. M. 
Published: July 2002

Magnetoresistivity values of the order of 106% (and in some cases even higher) have been obtained in epitaxial AxB1−xMnO3−y (A=La,Nd; B=Ca,Sr,Ba) thin films grown by pulsed laser deposition. Ferromagnetic resonance experiments suggest a granular-type behavior with conducting ferromagnetic regions (Rcond&lt;10 mΩ cm) in a less conducting matrix (Rinsulazting≳100.Rcond). Ion channeling experiments over a range of temperatures clearly reveal the existence of structural distortion at the peak resistivity temperature TP. Systematic studies of samples prepared under a variety of oxygenation conditions show that the resistivity above TP can be modeled with a single functional form: Rcond≊eΔ/kT, where Δ, the activation energy, is of the order of 50–200 meV. This suggests that these different samples represent the same basic material in a semiconducting matrix, with differing volume fractions of the two components which depends on the processing conditions. These ‘‘colossal’’ values of MR have been obtained at temperatures lower than room temperature and at fields of the order of a few Teslas, both of which are impediments to the development of viable MR sensor and nonvolatile storage technologies.
We are therefore addressing the critical scientific and technological issues through a variety of materials integration approaches. Using structural chemistry and lattice matching as fundamental guiding principles, we are growing epitaxial heterostructure superlattices consisting of the CMR oxides interleaved with magnetic perovskites such as La–Sr–Co–O (metallic ferromagnet), rare earth–Fe–O (ferromagnetic insulator). We are also exploring the possibility of using the semiconducting properties of these materials in an all-perovskite field effect transistor device. In this presentation, we will describe our progress to date on these studies to enhance the field and temperature dependence of the MR properties and explore new device architectures that utilize the inherently novel properties of these materials.
Giant magnetoresistance in evaporated NiFe/Cu and NiFeCo/Cu multilayers (abstract)
Authors: Zeltser A. M. , Smith Neil 
Published: July 2002

The magnetic and transport properties of electron beam evaporated (Ni83Fe17/Cu)10 and (Ni66Fe16Co18/Cu)10 multilayers (ML) were studied as a function of the Cu spacer and magnetic layer thicknesses (tCu and tNiFe), annealing conditions and Ta buffer layer thickness. The ML were evaporated in a magnetic field at deposition rates ∼ 2 Å/s and background pressure &lt;5×10−8 mbar on Si/SiO2 substrates at Ts=200 °C. These ML exhibited two unique features: (1) ΔR/R and the interlayer coupling did not show oscillatory behavior as a function of tCu; and (2) after magnetic post annealing, ΔR/R increased from &lt;0.3% in the as-deposited state, to up to ∼6% and 7% in Ta/(NiFe/Cu) and (NiFeCo/Cu), respectively. The coupling between the NiFe layers changed from ferromagnetic in the as-deposited state Mr/Ms∼0.9k;20 to essentially antiferromagnetic Mr/Ms&lt;0.2) after appropriate annealing, and the ML became virtually isotropic in-plane.
This is quite different from strong oscillatory behavior of giant magnetoresistance (GMR) previously reported in (NiFe/Cu) as-deposited ML made by ion-beam sputtering. After annealing at 300° and 325 °C for 2 h, the ΔR/R became ∼4.5% and ∼6.5% in (NiFe/Cu) and (NiFeCo/Cu) ML, respectively, and remained approximately constant for tCu=20 to 40 Å. The coupling field generally decreased with an increase in Cu and NiFe and after annealing at 300 °C dropped to as low as ∼25 and 45 Oe in (NiFe/Cu) and (NiFeCo/Cu) ML, respectively. The of ΔR/R Ta/(NiFe/Cu) ML increased with the thickness of Ta buffer layer from 30 to 70 Å. The high-angle θ–2θ x-ray scans of (NiFe/Cu) ML showed (111) texture, essentially independent of annealing temperature.
The low-angle x-ray diffraction did not reveal roughening of the Cu–NiFe interfaces as a result of annealing. In many respects the GMR behavior of these ML is similar to that reported in sputtered ‘‘discontinuous’’ NiFe/Ag. However, in contrast to the latter, the resistivity of NiFe/Cu monotonically increases with annealing temperature. This suggests that lattice interdiffusion is more prominent in the NiFe– system, consistent with a greater equilibrium compared solubility of Cu in the NiFe matrix compared to that of Ag. It is believed that Cu diffusion along the NiFe grain boundaries creates intra-layer magnetic discontinuity in NiFe and promotes inter-layer antiferromagnetic coupling between adjacent NiFe layers, which then gives rise to the observed GMR. Evaporated NiFe/Cu ML showed very small hysteresis and uniform GMR properties throughout the thickness, which makes them good candidates for GMR–DMR heads.
A new type of spin glass in spin-density-wave CrMn alloys (abstract)
Authors: Galkin V. Yu. , de Camargo P. C. , Ali Naushad , Schaf J. , Fawcett E. 
Published: July 2002

The temperature dependence of the susceptibility χ(T)=M(T)/H of Cr1−xMnx(≪0.1&lt;x&lt;8% Mn) alloys in the range 5&lt;T&lt;400 K and in fields up to 55 kOe, measured with a SQUID magnetometer, and hysteresis of the magnetization M(H) show typical spin-glass (SG) behavior. After zero-field cooling (ZFC), χ(T) exhibits the low-T maximum typical of a SG, while cooling in the measuring field (FC) gives quite different behavior. In some cases, when measuring at low field, χ(5 K) is 10× larger in the FC state than in the ZFC state. The temperature of the irreversibility limit decreases with increasing field. All our CrMn alloys show nonlinear field dependence of M(H), with pronounced hysteresis and decay of the remanent M with time. On the other hand, these alloys exhibit properties that are essentially different from those of all other metallic spin glasses: (1) the linear scaling law based on the RKKY interaction between magnetic impurities in a typical SG is not obeyed, and indeed the temperature of the maximum in χ(T) is essentially independent of Mn concentration, which shows that formation of the SG state does not depend on the distance between the Mn atoms; (2) the maximum in χ(T) in the alloy containing only a trace of Mn (≪0.1%) is at about 40 K, a temperature at least an order of magnitude larger than that in CuMn and other metallic SG with about 0.1% impurity concentration; (3) χ(T) obeys a Curie–Weiss law above the Neel temperature, but not below, which shows that the Mn moment is frozen in the spin-density-wave (SDW) matrix
We propose a model to explain this unusual behavior, in which the SG state is formed, not as a result of frustration of the Mn impurity moments, but through the frustration of the moments of the itinerant electrons of the host Cr. At low temperatures the frozen Mn moments pin the SDW, which gives rise to frustration surfaces between adjacent domains having different phase of the SDW. This effect depends only on the T-dependent interaction between the Mn moment and its neighbors, and thus is independent of the Mn concentration.
Engineering coercivities by dual ion beam sputtering for synthesizing soft permalloy-based spin-valve multilayers (abstract)
Authors: Gutierrez C. J. , Dail R. , Selestino R. , Tristan L. , Khater M. , Michel Steve 
Published: July 2002

Thin permalloy (Ni80Fe20) single-layer films and multilayers were fabricated onto Ta-buffered oxidized silicon substrates using a prototype dual ion beam sputtering system (Commonwealth Scientific Corporation). The room temperature substrates were placed in a uniform in-plane magnetic field during growth (∼150 Oe) yielding a uniaxial magnetic anisotropy in the permalloy films (typically ∼6 Oe). An examination of single-layer permalloy films with thicknesses from 20–50 nm indicated that the presence of an ∼100 eV ion-beam assist beam focused directly onto the substrate during film growth consistently modified the coercive and remnant characteristics of the films. Typically, the nonion beam assist modified NiFe films exhibited a coercivity ∼1 Oe, while the ion beam assist modified films exhibit a slightly larger coercivity (∼1.5 Oe).
Based on this apparent influence of the assist ion beam treatment on the film coercivity, the fabrication of soft spin-valve multilayer structures exploiting differences in the ion beam treatment of chemically identical ferromagnetic layers seemed plausible. To test this idea ,two parallel series of multilayers composed of [2.5 nm permalloy]-[Cu (2.5 nm, 4 nm, or 5.5 nm)] or [0.3 nm Co-1.9 nm permalloy -0.3 nm Co]-[Cu (2.5 nm, 4 nm, or 5.5 nm)] were fabricated. In these 30 cycle multilayers, alternating ferromagnetic layers were subjected to a 150 eV assist ion beam treatment during growth (higher coercivity layer), or to NO assist ion beam treatment during growth (lower coercivity layer). VSM analysis revealed that the simplest uncoupled spin-valve multilayer configuration consisted of the [2.5 nm permalloy]-[4 nm Cu] multilayer with Hc1 ∼0.8 Oe and Hc2 ∼2.2 Oe, and the [0.3 nm Co - 1.9 nm permalloy - 0.3 nm Co] - [4 nm Cu] multilayer with Hc1 ∼ 3 Oe and Hc2 ∼ 15 Oe. Film analysis by low-angle x-ray diffraction and reflectivity, as well as the effect of the Co interface layer on GMR properties will also be reported.
A magnetic, neutron diffraction, and Mȯssbauer spectral study of the Ce2Fe17−xAlx solid solutions (abstract)
Authors: Mishra Sanjay R. , Long Gary J. , Pringle O. A. , Hu Z. , Yelon W. B. , Middleton D. P. , Buschow K. H. J. , Grandjean F. 
Published: July 2002

The magnetic properties of a series of Ce2Fe17−xAlx solid solutions with x equal to 0.0, 0.88, 2.06, 2.80, 3.98, 5.15, 6.08, 7.21, 8.20, 9.08, 9.84, and 10.62 have been studied by magnetic measurements, neutron diffraction, and Mössbauer spectroscopy. Neutron diffraction data indicate that the compounds all crystallize in the rhombohedral Th2Zn17-type structure. The aluminum atoms are excluded from the 9d site and show a distinct preference for the 6c site for x greater than 6. The substitution of aluminum leads to an expansion of the a and c axis by 0.5% and 0.4% per aluminum atom. The unit cell volume increases by approximately 1.4% per aluminum atom. The magnetic moment per formula unit, measured at 295 K, shows very little change for x less than or equal to 4, but decreases rapidly with increasing aluminum content for higher values of x, indicating that aluminum acts as a magnetic hole at the lower concentrations. The Curie temperature increases from 238 K in Ce2Fe17 to a maximum of 384 K in Ce2Fe14Al3. The Ce2Fe17−xAlx solid solutions behave as spin glasses for x greater than 7.
The Mössbauer spectra have been fit with a binomial distribution of the near-neighbor environments in terms of a maximum hyperfine field, Hmax, for an iron atom with zero aluminum near neighbors, and a decremental field, ΔH, per aluminum near neighbor. Mössbauer spectral results indicate both that the samples are ferromagnetically ordered in the basal plane for x values between 0.2 and 7 and that a magnetic phase transition occurs from helimagnetic in Ce2Fe17 to ferromagnetic in Ce2Fe16.8Al0.2. However, at 295 K ferromagnetic ordering is observed only for x values between 2 and 5. The average value of Hmax decreases by about 25 kOe per aluminum atom. The isomer shift increases with aluminum content, an increase which can be explained by the screening of the 4s conduction electrons by the 3d band electrons. ΔH decreases by about 1.0 kOe per aluminum atom, a decrease which can be explained by the indirect exchange interaction between iron atoms modified by the presence of non-magnetic aluminum atoms through the 4s conduction band. Note added in proof: A full account of this work has been published in J. Appl. Phys. 79, 3145 (1996).
Attrition in group therapy with alcoholics: a survival analysis
Authors: ARNAU MIQUEL MONRAS , GUAL ANTONI 
Published: July 2002

AbstractThree hundred and twenty‐nine alcohol dependent patients, diagnosed according to DSM. III‐R criteria who had participated in one of five different psychotherapy groups over a 5‐year period, were studied using survival analysis statistics. Patients were followed‐up until their discharge or withdrawal from the group to determine their retention in therapy, and to examine the effect of gender, age and family situation on compliance. Retention rates at 6, 12 and 24 months were 61%, 49% and 37%, respectively. Median retention time was 46 weeks. Women remained longer in treatment than men (median period 98 vs. 34 weeks), and this was due mainly to lower dropout rates in the first 3 months. Dropout rates were also higher in patients aged 35 years or younger. The first 3 months seem to be crucial in the process of deciding whether or not to remain in therapy.
The acute cardiovascular effects of 3,4‐methylenedioxymethamphetamine (MDMA) and p‐methoxyamphetamine (PMA)
Authors: Irvine Rodney J. , Toop Natasha P. , Phillis Benjamin D. , Lewanowitsch Tanya 
Published: July 2002

AbstractA number of reports of severe acute toxicity as a result of recreational ingestion of what was believed to be 3,4‐methylenedioxymethamphetamine (MDMA) (ecstasy) have revealed, on chemical analysis of the victim's blood, to be due to p‐methoxyamphetamine (PMA). Increased blood pressure and heart rate have been associated with this toxicity, which is exacerbated by high ambient temperature. We compared MDMA and PMA effects on blood pressure and heart rate in conscious freely moving rats at ambient temperatures of 20°C and 30°C. Drugs were administered at 5, 10, 15 and 20 mg/kg s.c. and cardiovascular recordings continued 2–4 hours post‐drug. At 20°C MDMA had a slight lowering effect on blood pressure or heart rate at all doses tested. In contrast, PMA administered at the same ambient temperature caused a dose‐dependent long‐lasting bradycardia and lowering of blood pressure. At 30°C MDMA caused a slight increase in heart rate and a moderate rise in blood pressure. PMA did not significantly change heart rate or blood pressure at any of the doses tested. ECG was only influenced at the highest dose (20 mg/kg) of PMA and MDMA administered at 30°C where ST elongation was observed. These data indicate that although these drugs are considered similar in their psychotrophic effects they have different actions on the cardiovascular system of the rat. These findings may have implications in the diagnosis and emergency treatment of victims of MDMA/PMA toxicity.