Small bowel metastasis from embryonal rhabdomyosarcoma of the extremity- a case report.

Rhabdomyosarcoma is the most common soft tissue tumour in children and adolescents, but extremely rare in adults with comparatively worse outcomes. Metastatic disease is not uncommon, but intra-abdominal metastases are exceedingly rare. We report an unusual case of ileal metastases from an upper extremity rhabdomyosarcoma in a 17-year-old male who presented with abdominal pain during a routine follow-up visit. Laparotomy and ileocecectomy for a perforated ileal mass confirmed metastatic embryonal rhabdomyosarcoma with 1 out of 14 positive lymph node metastases. This case demonstrates that, although rare, intra-abdominal metastases should be considered when patients with a rhabdomyosarcoma present with abdominal complaints.

Small bowel metastasis from embryonal rhabdomyosarcoma of the extremity- a case report.

Rhabdomyosarcoma is the most common soft tissue tumour in children and adolescents, but extremely rare in adults with comparatively worse outcomes. Metastatic disease is not uncommon, but intra-abdominal metastases are exceedingly rare. We report an unusual case of ileal metastases from an upper extremity rhabdomyosarcoma in a 17-year-old male who presented with abdominal pain during a routine follow-up visit. Laparotomy and ileocecectomy for a perforated ileal mass confirmed metastatic embryonal rhabdomyosarcoma with 1 out of 14 positive lymph node metastases. This case demonstrates that, although rare, intra-abdominal metastases should be considered when patients with a rhabdomyosarcoma present with abdominal complaints.

Strain relaxation dynamics of multiferroic orthorhombic manganites.

Resonant ultrasound spectroscopy has been used to characterise strain coupling and relaxation behavior associated with magnetic/magnetoelectric phase transitions in GdMnO3, TbMnO3and TbMn0.98Fe0.02O3through their influence on elastic/anelastic properties. Acoustic attenuation ahead of the paramagnetic to colinear-sinusoidal incommensurate antiferromagnetic transition at ∼41 K correlates with anomalies in dielectric properties and is interpreted in terms of Debye-like freezing processes. A loss peak at ∼150 K is related to a steep increase in electrical conductivity with a polaron mechanism. The activation energy,Ea, of ≳0.04 eV from a loss peak at ∼80 K is consistent with the existence of a well-defined temperature interval in which the paramagnetic structure is stabilised by local, dynamic correlations of electric and magnetic polarisation that couple with strain and have relaxation times in the vicinity of ∼10-6s. Comparison with previously published data for Sm0.6Y0.4MnO3confirms that this pattern may be typical for multiferroic orthorhombicRMnO3perovskites (R= Gd, Tb, Dy). A frequency-dependent loss peak near 10 K observed for TbMnO3and TbMn0.98Fe0.02O3, but not for GdMnO3, yieldedEa⩾ ∼0.002 eV and is interpreted as freezing of some magnetoelastic component of the cycloid structure. Small anomalies in elastic properties associated with the incommensurate and cycloidal magnetic transitions confirm results from thermal expansion data that the magnetic order parameters have weak but significant coupling with strain. Even at strain magnitudes of ∼0.1-1‰, polaron-like strain effects are clearly important in defining the development and evolution of magnetoelectric properties in these materials. Strains associated with the cubic-orthorhombic transition due to the combined Jahn-Teller/octahedral tilting transition in the vicinity of 1500 K are 2-3 orders of magnitude greater. It is inevitable that ferroelastic twin walls due to this transition would have significantly different magnetoelectric properties from homogeneous domains due to magnetoelastic coupling with steep strain gradients.

Exchange bias in bulk layered hydroxylammonium fluorocobaltate (NH3OH)2CoF4.

The magnetic properties of layered hydroxylammonium fluorocobaltate (NH(3)OH)(2)CoF(4) were investigated by measuring its dc magnetic susceptibility in zero-field-cooled (ZFC) and field-cooled (FC) regimes, its frequency dependent ac susceptibility, its isothermal magnetization curves after ZFC and FC regimes, and its heat capacity. Effects of pressure and magnetic field on magnetic phase transitions were studied by susceptibility and heat capacity measurements, respectively. The system undergoes a magnetic phase transition from a paramagnetic state to a canted antiferromagnetic state exhibiting a weak ferromagnetic behavior at T(C) = 46.5 K and an antiferromagnetic transition at T(N) = 2.9 K. The most spectacular manifestation of the complex magnetic behavior in this system is a shift of the isothermal magnetization hysteresis loop in a temperature range below 20 K after the FC regime-an exchange bias phenomenon. We investigated the exchange bias as a function of the magnetic field during cooling and as a function of temperature. The observed exchange bias was attributed to the large exchange anisotropy which exists due to the quasi-2D structure of the layered (NH(3)OH)(2)CoF(4) material.

Transverse magnetism in uniaxial antiferromagnet UNiGa.

UNiGa crystallizes in the hexagonal ZrNiAl structure and orders antiferromagnetically below T(N)=39.3 K with the U moments oriented along the c-axis (easy magnetization axis). There are four different antiferromagnetic phases in zero magnetic field and two field induced magnetic phases in UNiGa. For all of them, a strong uniaxial anisotropy is encountered. All the magnetic phases are described by propagation vectors of (0 0 q(i))-type, where q(i) describes the stacking of the ferromagnetic basal planes along the hexagonal c-axis. However, recently (0 0 L)-type Bragg reflections associated with the magnetic ordering have been observed by neutron diffraction. Based on unpolarized and polarized neutron diffraction and non-resonant and resonant synchrotron x-ray scattering experiments combined with polarization analysis we conclude that small amounts of magnetic moments oriented perpendicular to the c-axis exist in UNiGa. Whether these moments reside on Ni atoms outside the U-Ni planes or at interstitial regions could not be determined.

Effect of pressure on the magnetic properties of TM(3)[Cr(CN)(6)](2)·12H(2)O.

We present the results of magnetization and AC susceptibility measurements performed on ferrimagnetic Mn(3)(2+)[Cr(III)(CN)(6)](2)·12H(2)O and ferromagnetic Ni(3)(2+)[Cr(III)(CN)(6)](2)·12H(2)O systems under pressures up to 0.9 GPa in a commercial SQUID magnetometer. The magnetization process is affected by pressure: magnetization saturates at higher magnetic field, saturated magnetization µ(s) of Ni(3)[Cr(CN)(6)](2) is reduced and almost unaffected for Mn(3)[Cr(CN)(6)](2) at low temperatures. The Curie temperature T(C) of Mn(3)[Cr(CN)(6)](2) increases with the applied pressure, ΔT(C)/Δp = 25.5 K GPa(-1), due to a strengthened super-exchange antiferromagnetic interaction J(AF), but it is not affected significantly in the case of Ni(3)[Cr(CN)(6)](2) with a dominant ferromagnetic J(F) super-exchange interaction. The increase in the J(AF) interaction is attributed to the enhanced value of the single electron overlapping integral S and the energy gap Δ of the mixed molecular orbitals t(2g) (Mn(2+)) and t(2g) (Cr(III)) induced by pressure.

Evidence for weak itinerant long-range magnetic correlations in UGe2.

Positive muon spin relaxation measurements performed on the ferromagnet UGe2 reveal, in addition to the well-known localized 5f-electron density responsible for the bulk magnetic properties, the existence of itinerant quasistatic magnetic correlations. Their critical dynamics is well described by the conventional dipolar Heisenberg model. These correlations involve small magnetic moments.

Biomonitoring environmental contaminants near a municipal solid-waste combustor: a decade later.

During the 1999 nesting season, eggs and nestlings of anhingas (Anhinga anhinga) and white ibises (Eudocimus albus) were collected from a colony located on the site of a municipal solid-waste (MSW) combustor and analyzed for residues of chemicals potentially released from this facility. Concentrations of most residues, including tetrachlorodibenzo-p-dioxin (TCDD). tetrachlorodibenzofuran (TCDF), arsenic, beryllium, cadmium and lead, were at levels comparable to those found during a similar survey done in 1989, prior to facility start-up. Nickel residues were detected only sporadically in anhingas and in eggs from ibises, and decreased significantly in concentration in ibis nestlings in 1999 compared to 1989. While concentrations of mercury in anhinga nestlings and in eggs of both species were comparable to 1989 levels, its concentration was significantly greater in ibis nestlings in 1999. However, levels of mercury in the ibises remained relatively low when compared to birds from other areas of Florida and did not appear to represent a health threat. While lead did not increase in 1999, its concentration in ibis nestlings remained a concern. The most notable temporal trend observed in birds at this site was a general monotonic decrease in levels of selenium residues during the 10-year monitoring period.

Biomonitoring environmental contaminants near a municipal solid-waste combustor.

Tetrachlorodibenzo-p-dioxin (TCDD), tetrachlorodibenzofuran (TCDF) and selected metal concentrations were measured in eggs and nestlings of anhingas (Anhinga anhinga) and white ibises (Eudocimus albus) collected from a colony next to a municipal solid-waste (MSW) combustor and ash landfill. Most of the measured residues, including TCDD, TCDF, arsenic, beryllium, cadmium and nickel, remained at pre-operational levels during the first five years of facility operation. Selenium (in anhingas) and mercury (in both anhingas and ibises) occurred at their lowest concentrations in samples collected during the fifth year of facility operation (Year-5). Alternatively, concentrations of lead in ibis nestlings were highest in Year-1 and Year-5 compared to Year-0. The MSW combustor could neither be ruled out nor confirmed as the source of this lead.

Determination of hematocrit based on diffusion of an inert molecular probe from agarose gels into whole blood.

Whole blood hematocrit was determined by an approach which depends on the diffusion of an inert probe, to which red blood cells are impermeable, from a small agarose gel into a stirred, much larger blood sample. Blood cells influence the diffusion rate of the probe by, on the average, physically blocking a fraction of the gel surface. The blocking effect increases with the hematocrit. Cyanocobalamin (B-12) was found to be a suitable probe because it did not penetrate, bind to, or lyse blood cells and was not bound by plasma solutes. The loss of B-12 from gels in contact with blood was monitored by determination of the absorbance change at 540 nm of gels which had been quickly rinsed. The visible spectrum of B-12 in agarose gels was identical to the spectrum in water. Beer's Law was obeyed in 1-mm thick agarose gels over a concentration range of 0.1-0.8 mM. Based on the results from 48 blood samples covering the hematocrit range 25-69, a least-squares line was generated with a slope, -3.46 X 10(-3) delta A/hematocrit unit, a Y intercept of 0.295, and a correlation coefficient of 0.971. The precision of the technique was +/- 9.7%. The assay was insensitive to mean corpuscular volume and sample volume as long as the latter was 50-fold larger than the gel volume. The diffusion coefficient for B-12 in 1% agarose gels was found to be 1.4 +/- 0.2 X 10(-6) cm2 sec-1.