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1.
Energy Fuels ; 35(13): 10898-10907, 2021 Jul 01.
Article in English | MEDLINE | ID: mdl-34276127

ABSTRACT

1D Ca3Co2-z M z O6 (M = Co z = 0, M = Mn z = 1, and M = Fe z = 0.4) were prepared and tested electrochemically. While the iron-containing phase was not found to be active, the iron- and manganese-containing phases were found to be potentially interesting as positive electrode materials for calcium metal-based high-energy battery technologies and were investigated by operando synchrotron X-ray diffraction. Results indicate that electrochemically driven calcium deintercalation from the crystal structure (ca. 0.7 mol per formula unit) takes place upon oxidation in both cases. The oxidized phases have incommensurate modulated crystal structures with the space group R 3m(00γ)0s and a = 9.127(1) Å, c 1 = 2.4226(3) Å and c 2 = 4.1857(3) Å, and γ = 0.579 (M = Co) and a = 9.217(1) Å, c 1 = 4.9076(4) Å and c 2 = 4.3387(4) Å, and γ = 1.139 (M = Mn), which exhibit differences due to the presence of manganese and Mn/Co ordering. The degree of calcium re-intercalation within the structure was found to be extremely limited, if any. Complementary experiments carried out in lithium cells did not show any reversibility either, thus pointing at intrinsic structural/migration constraints in the oxidized phase rather than slow kinetics of high desolvation energies associated with divalent ion charge carriers.

2.
RSC Adv ; 11(42): 26421-26431, 2021 Jul 27.
Article in English | MEDLINE | ID: mdl-35479462

ABSTRACT

CoSb3 thermoelectric skutterudite has been filled with rare-earth metals (M = La, Ce, Yb) and partially doped with Sn in specimens of M x Co4Sb12-y Sn y stoichiometry. This has been achieved under high-pressure conditions at 3.5 GPa in a piston-cylinder hydrostatic press. A structural investigation using synchrotron X-ray diffraction data reveals a phase segregation in twin skutterudite phases with filling fraction fluctuation and different unit-cell sizes. As a result of three effects acting as phonon scatterers, namely the rattling effect of M at the wide 8a cages of the cubic Im3̄ structure, the phase segregation, and the intrinsic disorder introduced by Sn substitution at the Sb sublattice, the total thermal conductivity (κ) dramatically falls to reach minimum values under 2 W m-1 K-1, well below those typically exhibited by other thermoelectric materials based upon single-filled skutterudites. The power factor is substantially enhanced to 1.11 mW m-1 K-2 in Yb0.5Co4Sb11.6Sn0.4 with respect to the unfilled composition, as a result of the charge transfer promoted by the filler.

3.
Phys Rev Lett ; 124(8): 087206, 2020 Feb 28.
Article in English | MEDLINE | ID: mdl-32167347

ABSTRACT

We report time-of-flight neutron spectroscopy and neutron and x-ray diffraction studies of the 5d^{2} double perovskite magnets, Ba_{2}MOsO_{6} (M=Zn,Mg,Ca). These materials host antiferromagnetically coupled 5d^{2} Os^{6+} ions decorating a face-centered cubic (fcc) lattice and are found to remain cubic down to the lowest temperatures. They all exhibit thermodynamic anomalies consistent with a single phase transition at a temperature T^{*}, and a gapped magnetic excitation spectrum with spectral weight concentrated at wave vectors typical of type-I antiferromagnetic orders. However, while muon spin resonance experiments show clear evidence for time-reversal symmetry breaking below T^{*}, we observe no corresponding magnetic Bragg scattering signal. These results are shown to be consistent with ferro-octupolar symmetry breaking below T^{*}, and are discussed in the context of other 5d double perovskite magnets and theories of exotic orders driven by multipolar interactions.

4.
J Phys Condens Matter ; 31(26): 265801, 2019 Jul 03.
Article in English | MEDLINE | ID: mdl-30893658

ABSTRACT

A systematic study of the physical properties and microscopic magnetism of Nd7Pd3 compound, which in the paramagnetic state crystallizes in the non-centrosymmetric hexagonal Th7Fe3-type structure (hP20-P63 mc; with a = 10.1367(1) Å and c = 6.3847(1) Å at 300 K), confirms multiple magnetic ordering transitions that occur upon cooling. Antiferromagnetic transition is observed at T N = 37 K, which is followed by ferromagnetic transformation at T C = 33 K. The first-order magnetic transition at T C is magnetoelastic: it involves a change of crystal symmetry from P63 mc to Cmc21 and leads to anisotropic changes of the unit cell parameters. While the antiferromagnetic structure is symmetry allowed in P63 mc, the ferromagnetic structure with magnetic moments along the a-direction of the original hexagonal unit cell induces the first order transition to Cmc21. Density functional theory calculations confirm the experimentally observed ground state with the a-axis as the easy magnetization direction.

5.
Sci Rep ; 6: 23415, 2016 Mar 22.
Article in English | MEDLINE | ID: mdl-27000414

ABSTRACT

In materials science, the substructure approach consists in imagining complex materials in which a particular property is associated with a distinct structural feature, so as to combine different chosen physical characteristics, which otherwise have little chance to coexist. Applied to thermoelectric materials, it has been used to achieve simultaneously phonon-glass and electron-crystal properties. Mostly studied for its superionic conductivity, AgCrSe2 is a naturally layered compound, which achieves very low thermal conductivity, ~0.4 W.K(-1).m(-1) at RT (room temperature), and is considered a promising thermoelectric. The Cr atoms of the [CrSe2]∞ layer bear a spin S = 3/2, which orders below TN = 55 K. Here we report low temperature inelastic neutron scattering experiments on AgCrSe2, alongside the magnetic field evolution of its thermal and electrical transport. We observe a very low frequency mode at 3 meV, ascribed to large anharmonic displacements of the Ag(+) ions in the [Ag]∞ layer, and 2D magnetic fluctuations up to 3 TN in the chromium layer. The low thermal conductivity of AgCrSe2 is attributed to acoustic phonon scattering by a regular lattice of Ag(+) oscillating in quasi-2D potential wells. These findings highlight a new way to achieve localised phonon modes in a perfectly crystalline solid.

6.
Ann Oncol ; 22(8): 1839-44, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21257672

ABSTRACT

BACKGROUND: Rituximab plus combination chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is widely recommended for the treatment of aggressive B-cell lymphomas. However, there is very little information regarding the management of elderly patients. PATIENTS AND METHODS: We initiated a phase II study of first-line treatment with rituximab and bendamustine in elderly patients (≥80 years) with aggressive B-cell lymphomas who were not eligible for R-CHOP or who did not agree to aggressive treatment. The treatment decision on eligibility for R-CHOP was left to discretion of the physicians. RESULTS: Fourteen patients with a median age of 85 years (range 80-95 years) were included. The age-adjusted international prognostic index was zero in five patients, one in three patients, and two in six patients. Thirteen patients were assessable for response. Seven patients (54%) had a complete response, two (15%) a partial response, and four (31%) progressive disease. The median overall survival was 7.7 months, and the median progression-free survival 7.7 months; however, six patients (43%) were alive without disease at 20-72 months from the start of treatment. Major toxicity was neutropenia (17% grade 3 and 6% grade 4). All other grade 3 and 4 hematotoxicities and non-hematological toxic effects ranged between 2% and 11% CONCLUSIONS: Because of its efficacy and low toxicity, bendamustine in combination with rituximab may be an alternative treatment for aggressive lymphomas in old patients not eligible for R-CHOP. These results, however, need to be confirmed in larger studies.


Subject(s)
Antibodies, Monoclonal, Murine-Derived/administration & dosage , Antineoplastic Combined Chemotherapy Protocols , Lymphoma, B-Cell/drug therapy , Nitrogen Mustard Compounds/administration & dosage , Aged, 80 and over , Antibodies, Monoclonal, Murine-Derived/adverse effects , Bendamustine Hydrochloride , Disease-Free Survival , Female , Humans , Lymphoma, B-Cell/pathology , Male , Neoplasm Staging , Neutropenia/etiology , Nitrogen Mustard Compounds/adverse effects , Rituximab
7.
J Phys Condens Matter ; 21(22): 224024, 2009 Jun 03.
Article in English | MEDLINE | ID: mdl-21715762

ABSTRACT

Ion beam irradiation has been shown to be an interesting tool for tailoring the magnetic properties of thin films and multilayers. The modified properties include magnetic anisotropy, interlayer exchange coupling, exchange bias, magnetic domain structure and magnetization reversal. In this work, new results are shown concerning the enhancement, by one order of magnitude, of the antiferromagnetic coupling strength in amorphous CoSi/Si multilayers by irradiating Si(100) substrates with 1 keV Ar(+) ions. The ion beam exposure induces an increase of the substrate roughness, from 0.07 to 0.88 nm, which enhances antiferromagnetic coupling in the magnetic multilayers grown on top. One possible mechanism governing this enhancement is discussed, related to the formation of magnetic/non-magnetic regions where dipolar interactions could stabilize the antiferromagnetic alignment. The presence of non-magnetic regions is suggested by the observed trend to superparamagnetism, and is expected since the Curie temperature of the amorphous CoSi alloy used is slightly above but very close to room temperature. Accordingly, small fluctuations in the local composition, leading to an enrichment of Si, would produce non-magnetic regions enabling dipolar interactions to take place. Furthermore, the ion beam induced increase of roughness makes surface diffusion of the atoms arriving at the sample difficult, favoring the formation of local non-magnetic inhomogeneities. Finally, the role of other possible mechanisms to enhance antiferromagnetic coupling is also briefly discussed.

8.
Ultraschall Med ; 27(3): 273-9, 2006 Jun.
Article in German | MEDLINE | ID: mdl-16767617

ABSTRACT

We report on a 49-year-old male patient who was suspected to have a malignant liver tumour with enlarged perihepatic lymph nodes because of CT and ultrasound scanning. To verify the diagnosis and procure a histological specimen, the patient underwent laparotomy. Histologically, an inflammatory pseudotumour could be confirmed. This is a rare disease which can present with fever, abdominal pain, vomiting and weight loss indicating malignancy or abscess. The definite diagnosis is often only verified by surgery.


Subject(s)
Granuloma, Plasma Cell/diagnostic imaging , Liver Diseases/diagnostic imaging , Liver Neoplasms/diagnostic imaging , Biopsy, Fine-Needle , Diagnosis, Differential , Granuloma, Plasma Cell/pathology , Granuloma, Plasma Cell/surgery , Humans , Liver Diseases/pathology , Liver Diseases/surgery , Male , Middle Aged , Treatment Outcome , Ultrasonography
9.
Phys Rev Lett ; 88(12): 126402, 2002 Mar 25.
Article in English | MEDLINE | ID: mdl-11909484

ABSTRACT

The first direct observation of charge order of Ni(3+delta(')) and Ni(3-delta) by resonant x-ray scattering experiments in an epitaxial film of NdNiO3 is reported. A quantitative value of delta+delta(') = (0.45 +/- 0.04)e was obtained. The temperature dependence of the charge order deviates significantly from those of the magnetic moment and crystallographic structure. This might be an indication of a difference in their fluctuation time scales. These observations are discussed in terms of the temperature-driven metal-insulator transition in the RNiO3 family.

10.
Leuk Res ; 25(3): 191-6, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11226513

ABSTRACT

AC133 is an antigen expressed on CD34+ hematopoietic progenitor cells. In acute myeloid leukemia (AML) it is expressed on leukemic blasts of most FAB subtypes. However, few data are available regarding coexpression of other surface antigens. We measured AC133 expression on AML blasts from 28 consecutive patients at initial diagnosis (n=26) or at diagnosis of first relapse (n=2) and on 26 leukapheresis products from 14 patients. In AML AC133 correlated with CD34 expression (Spearman r=0.4711, P=0.0114) and even stronger with combined CD34/CD33 expression (Spearman r=0.5083, P=0.0068). In leukapheresis products AC133 expression correlated with CD34 expression (Spearman r=0.7495, P=0.002) and the yield of the obtained amount of CD34+ cells (Spearman r=0.6484, P=0.0121). In conclusion AC133 expression is closely related to CD34 expression in AML. In leukapheresis products AC133 provides an additional marker for selection of PBPC autografts in AC133- AML.


Subject(s)
Glycoproteins/biosynthesis , Leukemia, Myeloid/diagnosis , AC133 Antigen , Acute Disease , Adult , Aged , Antigens, CD , Antigens, CD34/metabolism , Biomarkers, Tumor/metabolism , Bone Marrow Purging , Female , Hematopoietic Stem Cell Transplantation , Humans , Immunoglobulin Fab Fragments/metabolism , Immunophenotyping , Leukapheresis , Leukemia, Myeloid/metabolism , Leukemia, Myeloid/therapy , Male , Middle Aged , Peptides , Statistics, Nonparametric , Transplantation, Autologous
11.
Bone Marrow Transplant ; 25(8): 831-6, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10808203

ABSTRACT

In the present study the in vitro growth of CFU-GM from PBPC of patients with AML (n = 11), purged with mafosfamide alone or a combination of mafosfamide and amifostine, was compared to historical controls of mafosfamide-purged bone marrow (AML CR1, n = 16). Two patients were transplanted with mafosfamide and mafosfamide/amifostine pretreated PBPC autografts. The in vitro experiments demonstrated a significantly higher resistance of peripheral blood derived CFU-GM to mafosfamide (median ID95 190 microg mafosfamide/ml) compared with bone marrow derived CFU-GM (median ID95130 microg/ml). Preincubation with amifostine significantly further increased the median ID95 to 245 microg/ml. The clinical results showed short recovery times for neutrophils >500/microl (9 and 13 days) and platelets >20 000/microl (12 and 21 days) and stable long-term engraftment with one relapse at day +118 and one patient in CR at day 760 after transplantation. The in vitro results show a significant advantage of PBPC over bone marrow-derived progenitors for purging with mafosfamide. Furthermore, a protective effect from mafosfamide of amifostine on normal progenitors could be demonstrated. The clinical results demonstrate the clinical feasibility of using mafosfamide-purged autologous PBPCT without impairing the short-term and long-term repopulating capacities of the autografts.


Subject(s)
Amifostine , Bone Marrow Purging , Cyclophosphamide/analogs & derivatives , Granulocyte Colony-Stimulating Factor/pharmacology , Hematopoietic Stem Cell Mobilization , Leukemia/therapy , Stem Cells/cytology , Acute Disease , Adjuvants, Immunologic , Adult , Bone Marrow/drug effects , Bone Marrow Purging/methods , Female , Humans , Leukapheresis , Male , Middle Aged , Stem Cells/drug effects , Transplantation, Autologous
12.
Bone Marrow Transplant ; 25(1): 97-104, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10654022

ABSTRACT

Twenty autologous bone marrow (BM) and 25 peripheral blood stem cell (PBSC) grafts were collected from a total of 40 consecutive patients with BCR-ABL+ acute lymphoblastic leukemia (ALL) in first (n = 37) or second (n = 3) complete morphological remission and subsequently purged with a cocktail of anti-CD19, -CD10, AB4 MoAbs and immunomagnetic beads (IMB). Residual BCR-ABL-positive cells before purging were detected in 19 of 20 BM grafts at a median of 4 (range 0-6) logs and in 17 of 25 evaluable PBSC grafts at a median of 1 (range 0-3) log above the limit of detection assessed by a semiquantitative limiting log10-dilution RT-PCR (P < 0.0001). IMB purging depleted a median of 2.5 (range 1-4) log of residual BCR-ABL+ cells from BM and a median of 1 (range 0-2) log from PBSC grafts, achieving RT-PCR negativity in 1/20 BM and 12/25 PBSC grafts after purging. Cell recoveries were 62% and 86% (P < 0.0001) of MNC and 74% and 97% (P = 0.065) of CD34+ cells after BM and PBSC purging, respectively. BM purging was superior using the triple MoAb cocktail which depleted 2.64 +/- 0.4 log (n = 14) compared to 1.6 +/- 0.4 log (n = 5) using the MoAb cocktail not including AB4 (P = 0. 02). We conclude that unpurged BM grafts contain 2-3 log more residual BCR-ABL+ cells than unpurged PBSC grafts and that purging efficacy is superior in BM compared to PBSC grafts, but median titers in purged BM grafts still exceed those in purged PBSC grafts. Bone Marrow Transplantation (2000) 25, 97-104.


Subject(s)
Bone Marrow Purging/methods , Bone Marrow Transplantation , Fusion Proteins, bcr-abl/analysis , Hematopoietic Stem Cell Mobilization/methods , Hematopoietic Stem Cell Transplantation , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/therapy , Adolescent , Adult , Biomarkers, Tumor , Child, Preschool , Female , Fusion Proteins, bcr-abl/genetics , Humans , Immunomagnetic Separation , Male , Middle Aged , Neoplasm, Residual/diagnosis , Neoplasm, Residual/genetics , Polymerase Chain Reaction , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Transplantation, Autologous
13.
Beitr Infusionsther ; 30: 166-9, 1992.
Article in German | MEDLINE | ID: mdl-1284697

ABSTRACT

We report on an alternative to filtration for the preparation of leukocyte-poor red cell concentrates (LP-RCC). It is based on the method of Schneider. Using RCC with buffy coat it is comparably effective in leukocyte reduction [98.3 +/- 1.0%, (3.7 +/- 2.6) x 10(6) leukocytes] and more effective in platelet reduction (96.9 +/- 2.5%). Addition of PAGGS-M before heating (30 min, 37 degrees C) as well as after preparation significantly reduces hemolysis (free hemoglobin, LDH, HBDH) and improves the quality of the LP-RCC (ATP, 2,3-DPG) during storage for 24 h after preparation. LP-RCCs prepared with PAGGS-M after 6-day storage show still better quality than before preparation and about the same quality as LP-RCCs 24 h after conventional preparation with saline solution. In conclusion, by use of PAGGS-M and sterile docking LP-RCCs of adequate quality for 6-day storage can be prepared, improving the supply of the patients concerned.


Subject(s)
Blood Component Transfusion/instrumentation , Blood Preservation/instrumentation , Centrifugation/instrumentation , Leukapheresis/instrumentation , Lymphocyte Depletion/instrumentation , Adenine , Enzymes/blood , Glucose , Guanosine , Heating , Hematocrit , Hemoglobinometry , Humans , Leukocyte Count , Phosphates , Platelet Count , Sodium Chloride , Sorbitol
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