Comparison of two dosage regimens of the substrate for the [13C]methacetin breath test

The [¹³C]methacetin breath test ([¹³C]MBT) – a valuable non-invasive tool dedicated to the assessment of the liver metabolic capacity – still needs standardisation. The aim of this study was to check whether currently used dosage regimens of [¹³C]methacetin provide concordant [¹³C]MBT results in subjects with an atypical body constitution. Healthy volunteers: low body mass<55 kg (eight women), and high body mass>95 kg (eight large body frame men) were recruited. They underwent [¹³C]MBT on separate days, taking in random order [¹³C]methacetin: a fixed 75 mg dose (FX75), or a 1 mg kg^?1 body mass-adjusted dose (BMAD). Samples of expiratory air for ¹³CO₂ measurement were collected over 3 h. The maximum momentary ¹³C elimination in breath air occurred earlier and was higher following BMAD than with FX75 in the low body mass females (T _max 14.6±1.0 min vs. 22.1±2.4 min, p=0.019; D _max 41.9±2.9 % dose h^?1 vs. 36.6±3.6 % dose h^?1, p=0.071). In the high body mass men, T _max remained unchanged, whereas D _max was slightly higher with BMAD compared to FX75 (21.5±3.2 min vs. 23.0±3.0 min; 38.5±2.9 % dose h^?1 vs. 32.3±2.5 % dose h^?1). It is concluded that in subjects with a body constitution outside the general population average, the dosage of the substrate may affect some results of the [¹³C]MBT. The dosage-related differences appear, however, to be insignificant if the result of the [¹³C]MBT is reported as a cumulative ¹³C recovery in breath air.     

Debye temperature and magnetic ordering in K x Ba1−x Fe2S3

⁵⁷Fe Mössbauer measurements are reported for the series K _x Ba_1?x Fe₂S₃, x ≤ 0.3, at temperatures between 4.2 K ≤ T ≤ 294 K. A decrease of the Debye temperature from 435 to 405 K with x, indicates a weakening of the stiffness of the Fe sublattice. The ordering temperatures, taken from the appearance of magnetic hyperfine splitting in the spectra, are approximately 40 K lower for x ≥ 0.1. The values of the centre shift and the small temperature dependence of the quadrupole splitting strongly supports that similar to the border compound BaFe₂S₃ also the K containing samples should be characterised as mixed valence compounds.     

Rotational Analysis of the 1–4 Band of the B 2Σ+–X 2Σ+ System of 14C16O+

ABSTRACT

High-resolution emission spectrum of the 1–4 band of the B ²Σ⁺–X ²Σ⁺ transition of ¹⁴C¹⁶O⁺ was observed for the first time by conventional emission spectroscopy. The band spectrum was excited in a water-cooled Geissler lamp filled with commercial gaseous carbon monoxide enriched in about 80% of the radiocarbon ¹⁴C. A rotational analysis has been carried out and obtained molecular constants have been merged with previously published data for the B ²Σ⁺–A ²Π_i and A ²Π_i–X ²Σ⁺ transitions. The principal equilibrium constants for the ground X ²Σ⁺ state obtained from this work are ω_e = 2121.7726(98), ω_e x _e = 13.9055(27), B _e = 1.815290(30), α_e = 1.6594(33) × 10^?2, and γ_e = ? 0.377(73) × 10^?4 cm^?1. Also, presently known experimental equilibrium molecular constants of the X ²Σ⁺ states of the CO⁺ isotopic molecules are summarized and isotopic dependence of the B _e and ω _e constants is discussed.     

Near-Infrared Methane Detection Device Using Wavelength-Modulated Distributed Feedback Diode Laser around 1.654 µm

By using a wavelength-modulated distributed feedback laser centered at 1.654 µm, a stand-alone near-infrared methane detection device was experimentally proposed based on the tunable diode laser absorption spectroscopy technique. An intelligent temperature controller, a scan and modulation module, and a cost-effective lock-in amplifier were developed to drive the distributed feedback laser and extract the second harmonic signal. Experimental results show that the relative detection error is less than 7% within the detection range of 0–10⁶ ppm, and the limit of detection is about 11 ppm with an absorption length of 0.2 m. Long-term monitoring on two gas samples (10³ ppm and 2 × 10⁵ ppm) suggests good stability with the maximum detection errors smaller than 7% and 2.5%, respectively. Due to careful design and integration, the developed near-infrared sensor reveals competitive performances compared with our previously reported sensing devices at the mid-infrared region.     

Effect of oxalate test dose size on absolute and percent oxalate absorption

The purpose of this pilot study was to establish the dependence or independence of oxalate absorption on the quantity of the test dose of sodium oxalate over a range of test doses corresponding to physiological dietary oxalate intake values. Gastrointestinal oxalate absorption was measured with the [¹³C₂]oxalate absorption test. Six healthy volunteers were always tested under standardized dietary conditions with 63 mg dietary oxalate and 800 mg dietary calcium per day. The volunteers were tested thrice each with sodium oxalate test doses of 25, 50, 200, and 600 mg. Additionally, 1000 mg sodium oxalate was applied once to three of these volunteers. The oxalate absorption of the six volunteers tested under the standardized conditions with 50 mg sodium [¹³C₂]oxalate was 7.2 ± 2.62 % (mean ± SD), similar to the 120 volunteers tested previously: 8.0 ± 4.4 % (mean ± SD). The tests with sodium [¹³C₂]oxalate doses in the range 25–1000 mg revealed similar percent oxalate absorption values. In conclusion, in healthy volunteers, the amount of oxalate absorbed in the gastrointestinal tract increased proportionally with the higher test doses of oxalate. However, percent oxalate absorption remained unchanged with test doses in the dose range of physiological dietary oxalate intakes.     

Theoretical investigations of the local structure and the g factors for the tetragonal Ru3+ center in PbTiO3

The local structure and the g factors for the tetragonal Ru³⁺ center in PbTiO₃ are theoretically studied from the perturbation formulas of the g factors for a 4d⁵ ion in tetragonally distorted octahedra. From the studies, the distance between the impurity Ru³⁺ and the center of the oxygen octahedron is found to be about 0.283 Å, which is smaller than that (≈0.3 Å) for the host Ti⁴⁺ site. It appears that the impurity may not occupy exactly the host Ti⁴⁺ site but suffer a slight inward shift toward the center of the oxygen octahedron. The calculated g factors based on the above local structure show good agreement with the experimental values.     

Equilibrium and pre-equilibrium emissions in proton-induced reactions on <Superscript>203,205</Superscript>Tl

In this study, the excitation functions for the reactions ²⁰³Tl(p, n)²⁰³Pb, ²⁰⁵Tl(p, 3n)²⁰³Pb, ²⁰³Tl(p, 2n)²⁰²Pb, ²⁰⁵Tl(p, 4n)²⁰²Pb, ²⁰³Tl(p, 3n)²⁰¹Pb, ²⁰⁵Tl(p, 5n)²⁰¹Pb, ²⁰³Tl(p, 4n)²⁰⁰Pb and ²⁰⁵Tl(p, 6n)²⁰⁰Pb have been calculated using pre-equilibrium and equilibrium reaction mechanisms. Calculated results based on hybrid model, geometry-dependent hybrid model and cascade-exciton model have been compared with the experimental data.      

Doping and radiation damage profiles of P+ ions implanted in silicon along the [110] axis

Several doses of 200 KeV phosphorus ions have been implanted under channeling conditions along the [110] direction in silicon.

Range distribution has been determined for the three implant doses 10¹³, 10¹⁴, 10¹⁵ P⁺/cm² both with the electrical measurements and the neutron activation techniques.

The radiation damage distribution has been determined both with 290 KeV proton back-scattering analysis and with transmission electron microscopy (TEM) observations.

Good agreement has been found between electrical and neutron activation profiles in the samples where 100% of the implanted dose had been electrically activated by means of annealing.

Carrier concentration profiles, from samples implanted with 10¹⁵ P⁺/cm², determined after two different annealing temperatures (500°C and 700°C) have bcen compared with the radiation damage distribution and a correlation between damage and phosphorus electrical activation process seems to be possible.

Maximum damage peak, as determined by back-scattering analysis, shifts from ～0.4 μ depth in the lower dose(5 × 10¹⁴ P⁺/cm²), to ～0.22 pm depth in the higher implanted dose (4 × 10¹⁵ P⁺/cm²). Damage distribution of phosphorus ions random implanted in the same experimental conditions shows 3 peak at ～0.2 μn depth.

In accordance with the back-scattering analysis, T.E.M. observations on 10¹⁵P⁺/cm² implanted samples show the presence of amorphous regions at depth between 0.25 and 0.5 μm from the surface. In the most damaged layer ～0.3μm in depth, a surface density of ～10¹²/cm² amorphous regions 25-50 A diameter was observed.     

Eine Schnellmethode zur zerstörungsfreien aktivierungsanalytischen Bestimmung von Lanthan in Phosphaten

Eine Schnellmethode zur zerstörungsfreien aktivierungsanalytischen Bestimmung von Lanthan in Phosphaten wurde ausgearbeitet. Die Methode beruht auf der Messung der ¹¹⁰La-Aktivitāt (τ_½ = 40 h). Die Test- und Vergleichsproben wurden im IRT-1000-Reaktor bei einem Fluß von 1,6 · 10¹² n/cm²s bestrahlt. Die Messungen wurden mit einem 400-Kanal-γ-Spektrometer mit Li-Ge-Detektor und Na I(Tl)-Kristall durchgeführt. Die Auflösung des Li-Ge-Detektors betrug 0,2%, die des NaI(Tl)-Kristalls 7,6%. Die Standardabweichungen liegen bei 5% bei einem Lanthangehalt von 1% bis 0,01% und bei 10…15% bei einem Lanthangehalt von 0,01% bis 0,001%. Die Ergebnisse stimmen mit denen der Röntgenfluoreszenzanalyse überein.     

The B 2Σ+–X 2Σ+ Transition of 12C17O+: The 2‐υ″ Progression

Abstract

Three new bands of the B ²Σ⁺–X ²Σ⁺ system of ¹²C¹⁷O⁺ have been investigated using conventional spectroscopic techniques. The spectra were observed in a graphite hollow‐cathode lamp by discharging molecular oxygen (enriched in about 45% of the ¹⁷O₂ isotope) under 1.0 Torr pressure. The rotational analysis of the 2–4, 2–5, and 2–6 bands was performed with the effective Hamiltonian of Brown (Brown et al., J. Mol. Spectrosc. 1979; 74: 294–318). Molecular constants were derived from a merge calculation, including both the current wavenumbers and the spectroscopic data published by the authors previously. The principal equilibrium constants for the ground state of ¹²C¹⁷O⁺ are ω_e=2185.9658(84), ω_e x _e = 14.7674(11), B _e=1.927001(38), α_e=1.8236(22)×10^?2, γ_e=?0.331(28)×10^?4, D _e=6.041(12)×10^?6, β_e=0.100(31)×10^?7 cm^?1, and the equilibrium constants for the excited state are σ_e=45876.499(15), ω_e=1712.201(12), ω_e x _e=27.3528(39), B _e=1.754109(35), α_e=2.8706(57)×10^?2, γ_e = ?1.15(19)×10^?4, D _e=7.491(20)×10^?6, β_e=2.13(12)×10^?7, γ_e = 2.0953(97)×10^?2, and α_γe=?9.46(59)×10^?4 cm^?1, respectively. Rydberg–Klein–Rees potential energy curves were constructed for the B ²Σ⁺ and X ²Σ⁺ states of this molecule, and Franck–Condon factors were calculated for the vibrational bands of the B–X system.     

Effect of alcohol consumption on the liver detoxication capacity as measured by [13C]methacetin- and [methyl-13C]methionine-breath tests

The aim of this study was to investigate the hepatic microsomal and mitochondrial functions by using the ¹³CO₂-breath test in healthy subjects either before or after the consumption of red wine. Fourteen adults received [¹³C]methacetin and [methyl-¹³C]methionine together with a standardised dinner. Expired air samples were taken over 6 h. After a wash-out period, the subjects consumed 0.4 ml ethanol/kg/day together with dinner over a 10-day period. Thereafter, ¹³C-tracer administration was repeated under identical conditions. The ¹³CO₂-enrichments were measured by isotope ratio mass spectrometry. The mean cumulative percentage ¹³C-dose recovery (CPDR) after administration of [¹³C]methacetin and [methyl-¹³C]methionine either without or with red wine consumption amounted to 38.2±6.3 vs. 36.3±6.7% (p=0.363) and 9.5±3.3 vs. 8.8±2.5% (p=0.47), respectively. Moderate alcohol consumption does not induce significant short-term changes of the microsomal and the mitochondrial functions of the human liver in healthy subjects.     

Scintillation properties of pure and Ce3+-doped SrF2 crystals

In this paper results of scintillation properties measurements of pure and Ce³⁺-doped strontium fluoride crystals are presented. We measure light output, scintillation decay time profile and temperature stability of light output. X-ray excited luminescence outputs corrected for spectral response of monochromator and photomultiplier for pure SrF₂ and SrF₂-0.3 mol% Ce³⁺ are approximately 95% and 115% of NaI–Tl emission output, respectively. A photopeak with a 10% full width at half maximum is observed at approximately 84% the light output of a NaI–Tl crystal after correction for spectral response of photomultiplier, when sample 10 × 10 mm of pure SrF₂ crystal is excited with 662 keV photons. Corrected light output of SrF₂-0.3 mol% Ce³⁺ under 662 keV photon excitation is found at approximately 64% the light output of the NaI–Tl crystal.     

Optical Spectroscopy of YPO4 Single Crystals Doped with Ho3+

ABSTRACT

Crystal field absorption and emission spectra originated by ⁵I₈ ? ⁵F₅ transitions, due to Ho³⁺ (1% molar fraction) in a YPO₄ single crystal, were investigated in the 15000 to 16000 cm^?1 range. Fourier Transform high resolution absorption measurements, performed in the 9 to 300 K range, and photoluminescence, monitored at 10 K upon 540 nm excitation, supplied the sublevel separations within both ⁵I₈ and ⁵F₅ manifolds. The sublevel positions were compared to those calculated by diagonalization of the full 4f-configuration matrix in the framework of a single-ion model. The results are discussed also in relation with experimental data previously reported for similar systems containing Ho³⁺.     

237Np and 57Fe Mössbauer study of NpFeGa5

⁵⁷Fe and ²³⁷Np Mössbauer ōmeasurements have been performed for NpFeGa₅, which is one of the so-called neptunium 1-1-5 compounds. The ⁵⁷Fe Mössbauer spectra below T _N = 118 K show the magnetically ordered state. The magnitude of the hyperfine magnetic field at the ⁵⁷Fe nucleus is determined to be 1.98 ± 0.05 T at 10 K. From the ²³⁷Np Mössbauer spectrum at 10 K, the hyperfine magnetic field at the ²³⁷Np nucleus is 203 T and the hyperfine coupling constant is determined to be 237 T/μ_B using the Np atomic magnetic moment of 0.86 μ_B determined by the neutron diffraction study.     

A Study on Analysis of Labeling Efficiency Depending on Mixing Time in Asan Medical Center Red Blood Cell Labeling Method

The aim of this study was to overcome the shortcomings of technetium-99m red blood cell labeling, such as the requirement of additional time, and to maintain a stable labeling efficiency by reducing the mixing time for technetium-99m red blood cell labeling in the Asan Medical Center red blood cell labeling method developed by this hospital. Thirty patients, who underwent an examination using technetium-99m red blood cell labeling in the nuclear medicine department from April to September 2012, were selected randomly. Blood samples (5 mL per patient) were mixed with acid citrate dextrose, and 1-mL aliquots were taken to make four blood samples. The Asan Medical Center red blood cell labeling method was used for labeling. In this case, the mixing time was set to 5, 10, 15, and 20 min before calculating the efficiency of each labeling. The difference depending on the mixing time was compared. According to the technetium-99m red blood cell labeling efficiency depending on the mixing time in the Asan Medical Center red blood cell labeling method, the efficiency of each labeling was 92 ± 5%, 96 ± 5%, 97 ± 5%, and 98 ± 5% for 5, 10, 15, and 20 min, respectively. Overall, the labeling efficiency was relatively low when the mixing time was 5 min, whereas there was no significant difference in labeling efficiency when the mixing time was longer than 5 min. In conclusion, the Asan Medical Center red blood cell labeling method can provide an environment that is more conducive to the combination of red blood cell with technetium-99m pertechnetate than the previous modified labeling method because the Asan Medical Center red blood cell labeling method removes blood plasma in an additional centrifugation process.     

Mechanoluminescence and thermoluminescence of BaFCl:Sm 2+ and BaFBr:Sm 2+ crystals

The alkaline-earth fluorohalide crystals MFX, where M=Ca, Sr, Ba, Pb and X=Cl, Br, I, form an important class of materials crystallizing in the PbFCl-type tetragonal structure which is also called the matlockite structure. These compounds have long been of interest because of the various defect species which can be detected by spin resonance and associated techniques. The crystals were prepared by slow cooling of the melt of a stoichiometric mixture of BaF ₂ and the corresponding chloride or bromide under 0.2 bar of ultrapure argon (5N5), often slightly fluorinated. We have studied the mechanoluminescence (ML) of BaFBr:Sm ²⁺ and BaFCl:Sm ²⁺ crystals. It is seen that after the impact of a moving piston, initially the ML intensity increases with time, attains a maximum value and then it decreases with time up to a particular minimum value, and then it increases again, attaining a peak value and finally disappears. The first peak lies in the deformation region and the second peak lies in the post-deformation region. The ML intensity of the BaFCl:Sm ²⁺ crystal is much higher than the ML intensity of the BaFBr:Sm ²⁺ crystal. For different impact velocities, the ML intensity increases with velocity; and the total ML intensity attains a saturation value for higher impact velocities. The total ML intensity increases with the increase in the applied load. It is suggested that the moving dislocation produced during deformation of crystals captures holes from hole-trapped centers (like H centers), and the subsequent radiative recombination of the dislocation holes with electron gives rise to ML. Thermoluminescence (TL) of BaFBr:Sm ²⁺ and BaFCl:Sm ²⁺ crystals was studied after exposure to ultraviolet rays with the help of a TLD reader. The peak of TL for the BaFBr:Sm ²⁺ crystal is found at ～247°C and for BaFCl:Sm ²⁺ crystals at 283°C. The TL intensity initially increases with increase in the UV radiation and then it attains saturation for higher values of UV exposure. The absorption spectrum was recorded with the help of a UV–visible spectrophotometer (Shimadzu). The band found at 275 nm was attributed to H centers.     

Strong Visible and Near-Infrared Cathodoluminescence in Alkali Feldspar

In this study, cathodoluminescence (CL) spectroscopy at direct current and alternating current under the sample temperature condition of 40–293 K using different modulation frequencies is presented for alkali feldspar from the Dartmoor granite (UK). These feldspars contain strain-controlled lamellar crypto- and microperthites that are cross-cut by strain-free deuteric microperthites. The CL spectra of the alkali feldspar at room and low temperature confirm that the observed emission peaked at ～460 nm could be associated with Al-O^?-Al or Ti impurity centers, yellow emission ～560 nm could be associated with the presence of the centers such as radiation-induced defect centers, and ～756 nm emission could be associated with the Fe³⁺ impurity center on T₁ and T₂ sites. The consequence of their association is to produce different luminescence properties such as intensity, peak wavelength, and band shape.     

高能α粒子轰击Yb箔制备~(178)Hf~(m2)核素的初步研究

在CS30回旋加速器上利用27MeV的α粒子束轰击天然金属Yb箔.对辐照样品进行了分析,确定产生的178Hfm2核素约1.5×1011个,辨识出样品中主要的长寿命核素,并推断产生这些核素可能的核反应通道.基于对样品放射性剂量率跟踪监测结果,初步确定了样品的冷却时间.这些研究结果一方面验证了所选择的制备途径是可行的,另一方面也为进一步开展该核素制备技术研究提供了参考依据.     

Some studies of BF2 and B+F implanted Silicon

Ion-implanted shallow junctions have been investigated using BE₂ (molecular ions) by the anodic oxidation method coupled with a four-point probe technique. BF₂ ions were implanted through screen oxide at doses of 3–5 × 10¹⁵ ions/cm² and energies of 25 and 45 keV which is equivalent to 5.6 keV and 10 keV of boron ions. The effect of energy, dose and annealing temperature on shallow junctions is presented in this paper. The shallow junctions in the range of 0.19 μm to 0.47 μm were fabricated.

The effect of fluorine on sheet resistivity of boron implanted silicon at various doses, treated with two-step and three-step annealing, is also presented for comparison in the paper.     

Optical Analysis of Er3+:Boro-Fluoro-Phosphate Glasses

This paper deals with the preparation and optical analysis of Er³⁺ (0.2 mol%) boro-fluoro-phosphate glasses in the following glass compositions:

• Series A: 69.8 B₂O₃–10 P₂O₅–10(ZnO/CdO/TeO₂)–10 AlF₃

• Series B: 69.8 B₂O₃–10 P₂O₅–10(ZnO/CdO/TeO₂)–10 LiF

Measured Vis-NIR absorption spectra of Er³⁺:boro-fluoro-phosphate glasses have revealed nine absorption bands at 377 nm, 405 nm, 450 nm, 486 nm, 519 nm, 543 nm, 649 nm, 973 nm and 1529 nm, which correspond with the transitions of ⁴I_15/2 → ⁴G_11/2, (²G_9/2,⁴H_9/2), ⁴F_5/2, ⁴F_7/2, ²H_11/2, ⁴S_3/2, ⁴F_9/2, ⁴I_11/2, and ⁴I_13/2, respectively. With an excitation at λ _exci = 375 nm, a bright green emission (⁴S_3/2 → ⁴I_15/2) at 547 nm has been observed from these erbium glasses. Judd–Ofelt characteristic intensity Ω_λ (λ = 2, 4, 6) parameters are obtained from the absorption spectra, and these results were used to compute the radiative properties of Er³⁺:boro-fluoro-phosphate glasses. The NIR emission (⁴I_13/2 → ⁴I_15/2) at 1547 nm from these glasses was measured with an Ar⁺ laser (514.5 nm) as an excitation source.