355 research outputs found

    Specific Heat Study of 1D and 2D Excitations in the Layered Frustrated Quantum Antiferromagnets Cs2_2CuCl4x_{4-x}Brx_x

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    We report an experimental and theoretical study of the low-temperature specific heat CC and magnetic susceptibility χ\chi of the layered anisotropic triangular-lattice spin-1/2 Heisenberg antiferromagnets Cs2_2CuCl4x_{4-x}Brx_x with xx = 0, 1, 2, and 4. We find that the ratio J/JJ'/J of the exchange couplings ranges from 0.32 to 0.78\approx 0.78, implying a change (crossover or quantum phase transition) in the materials' magnetic properties from one-dimensional (1D) behavior for J/J<0.6J'/J < 0.6 to two-dimensional (2D) behavior for J/J0.78J'/J \approx 0.78 behavior. For J/J<0.6J'/J < 0.6, realized for xx = 0, 1, and 4, we find a magnetic contribution to the low-temperature specific heat, CmTC_{\rm m} \propto T, consistent with spinon excitations in 1D spin-1/2 Heisenberg antiferromagnets. Remarkably, for xx = 2, where J/J0.78J'/J \approx 0.78 implies a 2D magnatic character, we also observe CmTC_{\rm m} \propto T. This finding, which contrasts the prediction of CmT2C_{\rm m} \propto T^2 made by standard spin-wave theories, shows that Fermi-like statistics also plays a significant role for the magnetic excitations in frustrated spin-1/2 2D antiferromagnets

    FACKEL is a sterol C-14 reductase required for organized cell division and expansion in Arabidopsis embryogenesis

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    In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. We report that FK is required for cell division and expansion and is involved in proper organization of the embryo. We isolated FK by positional cloning. Expression analysis in embryos revealed that FK mRNA becomes localized to meristematic zones. FK encodes a predicted integral membrane protein related to the vertebrate lamin B receptor and sterol reductases across species, including yeast sterol C-14 reductase ERG24. We provide functional evidence that FK encodes a sterol C-14 reductase by complementation of erg24. GC/MS analysis confirmed that fk mutations lead to accumulation of intermediates in the biosynthetic pathway preceding the C-14 reductase step. Although fk represents a sterol biosynthetic mutant, the phenotype was not rescued by feeding with brassinosteroids (BRs), the only plant sterol signaling molecules known so far. We propose that synthesis of sterol signals in addition to BRs is important in mediating regulated cell growth and organization during embryonic development. Our results indicate a novel role for sterols in the embryogenesis of plants

    Enhanced Late Miocene Chemical Weathering and Altered Precipitation Patterns in the Watersheds of the Bay of Bengal Recorded by Detrital Clay Radiogenic Isotopes

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    The late Miocene was a period of declining CO2 levels and extensive environmental changes, which likely had a large impact on monsoon strength as well as on the weathering and erosion intensity in the South Asian Monsoon domain. To improve our understanding of these feedback systems, detrital clays from the southern Bay of Bengal (International Ocean Discovery Program Site U1443) were analyzed for the radiogenic isotope compositions of Sr, Nd, and Pb to reconstruct changes in sediment provenance and weathering regime related to South Asian Monsoon rainfall from 9 to 5 Ma. The 100 kyr resolution late Miocene to earliest Pliocene record suggests overall low variability in the provenance of clays deposited on the Ninetyeast Ridge. However, at 7.3 Ma, Nd and Pb isotope compositions indicate a switch to an increased relative contribution from the Irrawaddy River (by ∼10%). This shift occurred during the global benthic δ13C decline, and we suggest that global cooling and increasing aridity resulted in an eastward shift of precipitation patterns leading to a more focused erosion of the Indo‐Burman Ranges. Sr isotope compositions were decoupled from Nd and Pb isotope signatures and became more radiogenic between 6 and 5 Ma. Grassland expansion generating thick, easily weatherable soils may have led to an environment supporting intense chemical weathering, which is likely responsible for the elevated detrital clay 87Sr/86Sr ratios during this time. This change in Sr isotope signatures may also have contributed to the late Miocene increase of the global seawater Sr isotope composition

    Fertility Ideals of Women and Men Across the Life Course

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    This paper explores the stability of women’s and men’s fertility preferences across the life course. The data come from the first six waves of the German Family Panel (pairfam), which span the period from 2008/2009 until 2013/2014. In our analysis, fertility preferences are measured using the following question: “Under ideal circumstances, how many children would you like to have?” The average number cited by both women and men is 2.2. With rising age, this number declines modestly. Relying on fixed-effects modelling, we find that neither partnership status nor economic circumstances have any causal effect on fertility preferences. However, as the number of children a respondent has increases, his or her ideal number of children is also likely to grow. Thus, fertility ideals appear to undergo changes over time, and are adjusted in line with the size of the respondent’s own family

    Health status, use of healthcare, and socio-economic implications of cancer survivorship in Portugal : results from the fourth national health survey

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    Health status, use of healthcare, and socio-economic implications of cancer survivorship in Portugal: results from the Fourth National Health SurveyUnderstanding the morbidity and socio-economic implications of cancer survivorship is essential for a comprehensive management of oncological diseases. We compared cancer survivors (CS) with the general population regarding health status, use of healthcare resources and socio-economic condition. We analyzed data from a representative sample of the Portuguese population aged a parts per thousand yen15 years (n = 35,229). We defined three groups of CS, according to the time since diagnosis and the latest cancer treatment: CS 1 diagnosis within 12 months of interview; CS 2 diagnosis more than 12 months before and treatment in the previous 12 months; CS 3 diagnosis and treatment more than 12 months before. These were compared with the general population, adjusting for differences in sex, age, and place of residence. The prevalence of CS was 2.2 % (CS 1: 0.2 %; CS 2: 0.9 %, CS 3: 1.1 %). Self-perceived health status was worse among CS and short-time incapacity more frequent among CS 1 and CS 2. Health expenses were higher in the early stages of survivorship. Lower household income and financial difficulties were more frequent in CS 1 and CS 3 men, respectively. This study confirmed the higher consumption of healthcare resources and worse financial situation among CS. Our study provides valuable information for understanding the global impact of cancer survivorship.The authors thank the National Health Systems Observatory (Observatorio Nacional de Saude), National Institute of Health Dr. Ricardo Jorge (INSA), Ministry of Health and the National Institute of Statistics (INE) for providing the data (Ministerio da Saude, Instituto Nacional de Saude Dr. Ricardo Jorge; IP, Departamento de Epidemiologia/Instituto Nacional de Estatistica: Inquerito Nacional de Saude 2005/2006). Luis Pacheco-Figueiredo received a grant from the Fundacao para a Ciencia e a Tecnologia (SFRH/SINTD/60124/2009)

    Effects of conjugated linoleic acid on myogenic and inflammatory responses in a human primary muscle and tumor coculture model

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    The antiproliferative and anti-inflammatory properties of conjugated linoleic acid (CLA) make it a potentially novel treatment in chronic inflammatory muscle wasting disease, particularly cancer cachexia. Human primary muscle cells were grown in coculture with MIA PaCa-2 pancreatic tumor cells and exposed to varying concentrations of c9,t11 and t10,c12 CLA. Expression of myogenic (Myf5, MyoD, myogenin, and myostatin) and inflammatory genes (CCL-2, COX-2, IL-8, and TNF-) were measured by real-time PCR. The t10,c12 CLA isomer, but not the c9,t11 isomer, significantly decreased MIA PaCa-2 proliferation by between 15% and 19%. There was a marked decrease in muscle MyoD and myogenin expression (78% and 62%, respectively), but no change in either Myf5 or myostatin, in myotubes grown in coculture with MIA PaCa-2 cells. CLA had limited influence on these responses. A similar pattern of myogenic gene expression changes was observed in myotubes treated with TNF- alone. Several-fold significant increases in CCL-2, COX-2, IL-8, and TNF- expression in myotubes were observed with MIA PaCa-2 coculture. The c9,t11 CLA isomer significantly decreased basal expression of TNF- in myotubes and could ameliorate its tumor-induced rise. The study provides insight into the anti-inflammatory and antiproliferative actions of CLA and its application as a therapeutic agent in inflammatory disease states.<br /

    Radiotherapy in the treatment of Graves ophthalmopathy—to do it or not?

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    To the objective of this study is to evaluate the role and toxicity of radiotherapy in the treatment of Graves ophthalmopathy. In the years 2000–2003, 121 patients with malignant exophthalmos were treated with radiotherapy of the retrobulbar area to the total dose of 20 Gy in ten fractions with a 6 MeV photon beam. The treatment was performed by the team of the Clinic of Oncology of the Jagiellonian University Medical College in Cracow. The radiotherapy was preceded by intravenous steroid therapy: methylprednisolone acetate administered at the dose of 2 g/week for four consecutive weeks. The highest efficacy, expressed as improvement of all ocular symptoms, was observed for the combined treatment. Female and non-diabetic patients responded positively to the combined treatment. Radiotherapy combined with steroid therapy in the treatment of Graves ophthalmopathy seems to be an effective treatment for strictly defined indications. In the treatment of Graves–Basedow disease, radiotherapy is a well-tolerated treatment modality. Diabetes is a factor that worsens prognosis in Graves ophthalmopathy and female sex is a favourable factor for this condition

    Deformation Aware Augmented Reality for Craniotomy using 3D/2D Non-rigid Registration of Cortical Vessels

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    International audienceIntra-operative brain shift is a well-known phenomenon that describes non-rigid deformation of brain tissues due to gravity and loss of cerebrospinal fluid among other phenomena. This has a negative influence on surgical outcome that is often based on pre-operative planning where the brain shift is not considered. We present a novel brain-shift aware Augmented Reality method to align pre-operative 3D data onto the deformed brain surface viewed through a surgical microscope. We formulate our non-rigid registration as a Shape-from-Template problem. A pre-operative 3D wire-like deformable model is registered onto a single 2D image of the cortical vessels, which is automatically segmented. This 3D/2D registration drives the underlying brain structures, such as tumors, and compensates for the brain shift in sub-cortical regions. We evaluated our approach on simulated and real data composed of 6 patients. It achieved good quantitative and qualitative results making it suitable for neurosurgical guidance

    Successful treatment of mucosa-associated lymphoid tissue lymphoma in a patient with gastric and rectal lesions with metachronous and ectopic development

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    A 75-year-old female, who had an abnormal stomach x-ray finding, was admitted to the hospital for further examination and therapy. Upper GI endoscopy showed reddish and swollen folds on the greater curvature of the gastric body and a biopsy was of this lesion revealed malignant lymphoma (small cell type or mucosa-associated lymphoid tissue (MALT) lymphoma suspected). The patient was infected with Helicobacter pylori (H. pylori), however, in response to the patient's wishes, a total gastrectomy, omentectomy and splenectomy were performed and the histological diagnosis was gastric MALT lymphoma. Two courses of CHOP therapy (cyclophosphamide (CPM) 750 mg/m2/day, day 1, adriamycin (ADM) 50 mg/m2/day, day 1, vincristine sulfate (VCR) 1.4 mg/m2/day, day 1, prednisolone 100 mg/body, day 1–5) were administered as adjuvant chemotherapy. A colonoscopic examination performed about 4.5 yr after the operation revealed rectal submucosal tumors and the biopsied specimens were diagnosed as malignant lymphoma. A transanal focal resection was performed and the histological diagnosis was metachronous and ectopic development of MALT lymphoma. The histological finding was similar to the gastric lesion. About 4 and 7 yr after the first development of rectal MALT lymphoma, MALT lymphomas developed repeatedly in the rectal lesion, however, these were resected repeatedly and no developmenthas occurred during the past two years. This report presents a very rare case of metachronous and ectopic MALT lymphoma development in the gastric and rectal lesions
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