Divergent nematic susceptibility in an iron arsenide superconductor

Within the Landau paradigm of continuous phase transitions, ordered states of matter are characterized by a broken symmetry. Although the broken symmetry is usually evident, determining the driving force behind the phase transition is often a more subtle matter due to coupling between otherwise distinct order parameters. In this paper we show how measurement of the divergent nematic susceptibility of an iron pnictide superconductor unambiguously distinguishes an electronic nematic phase transition from a simple ferroelastic distortion. These measurements also reveal an electronic nematic quantum phase transition at the composition with optimal superconducting transition temperature.Comment: 8 pages, 8 figure

BENTONITE/CHITOSAN BIOCOMPOSITE AS AN ADSORBENT FOR HEXAVALENT CHROMIUM FROM AQUEOUS SOLUTIONS

The present work focuses on the study of the application of abundant and less expensive materials such as chitosan and bentonite/chitosan biocomposite in the removal of hexavalent chromium. Spectroscopic analysis like techniques FTIR, XRD and BET have been used to characterize the adsorbents. The data indicate that the adsorption of chromium proceeds kinetically according to a pseudo-second order model on both samples and the apparent activation energy (Ea) have been measured to be 22.9 kJ.mol−1 and 84.4 kJ.mol−1 for chitosan and 5%Bt/CS, respectively. The adsorption isotherm experiments show that the adsorption capacity depends on the studied chromium adsorption temperature. It has been found that the data could be well described by the Langmuir as well as the Freundlich models. Thermodynamic parameters (i.e., change in the free energy (DG°), the enthalpy (DH°), and the entropy (DS°) have been also, evaluated

INTRABDOMINAL DESMOPLASTIC SMALL ROUND CELL TUMOR: CASE REPORT WITH LITERATURE REVIEW

Intra-abdominal desmoplastic small round cell tumor arerrare aggressive neoplasm, with a very poor prognosis, observed in young adults with a male predominance, Their etiology is unknown and the diagnosis is based on histopathology, immunohistochemistry and cytogenetics. Histological analysis shows typically clusters of round cells separated by abundant desmoplastic stroma. These tumors exhibit a multi-marker immunohistochemistry profile expressing the three embryonic lineages: epithelial, neural and mesenchymal. They are positive for desmin and cytokeratin and are characterized by a specific recurring translocation t (11:22) (q12-p13), which involves EWSR! WT1 gene. They are usually fatal despite an aggressive multidisciplinary therapeutic approach. Hereby we report the case of 39 yera old man who presented with an intra-abdominal desmoplastic small round cell tumor. The diagnosis was made by radiological, histological and immunohistochemistry profile analyses of a CT scanguided biopsy. This articel includes a mini review of the literature

Nernst and Seebeck Coefficients of the Cuprate SuperconductorYBa2_2Cu3_3O6.67_{6.67}: A Study of Fermi Surface Reconstruction

The Seebeck and Nernst coefficients $S$ and $\nu$ of the cuprate superconductor YBa$_2$Cu$_3$O$_y$ (YBCO) were measured in a single crystal with doping $p = 0.12$ in magnetic fields up to H = 28 T. Down to T=9 K, $\nu$ becomes independent of field by $H \simeq 30$ T, showing that superconducting fluctuations have become negligible. In this field-induced normal state, $S/T$ and $\nu/T$ are both large and negative in the $T \to 0$ limit, with the magnitude and sign of $S/T$ consistent with the small electron-like Fermi surface pocket detected previously by quantum oscillations and the Hall effect. The change of sign in $S(T)$ at $T \simeq 50$ K is remarkably similar to that observed in La$_{2-x}$Ba$_x$CuO$_4$, La$_{2-x-y}$Nd$_y$Sr$_x$CuO$_4$ and La$_{2-x-y}$Eu$_y$Sr$_x$CuO$_4$, where it is clearly associated with the onset of stripe order. We propose that a similar density-wave mechanism causes the Fermi surface reconstruction in YBCO.Comment: Final version accepted for publication in Phys. Rev. Lett. New title, shorter abstract, minor revision of text and added reference

Symmetry breaking orbital anisotropy on detwinned Ba(Fe1-xCox)2As2 above the spin density wave transition

Nematicity, defined as broken rotational symmetry, has recently been observed in competing phases proximate to the superconducting phase in the cuprate high temperature superconductors. Similarly, the new iron-based high temperature superconductors exhibit a tetragonal to orthorhombic structural transition (i.e. a broken C4 symmetry) that either precedes or is coincident with a collinear spin density wave (SDW) transition in undoped parent compounds, and superconductivity arises when both transitions are suppressed via doping. Evidence for strong in-plane anisotropy in the SDW state in this family of compounds has been reported by neutron scattering, scanning tunneling microscopy, and transport measurements. Here we present an angle resolved photoemission spectroscopy study of detwinned single crystals of a representative family of electron-doped iron-arsenide superconductors, Ba(Fe1-xCox)2As2 in the underdoped region. The crystals were detwinned via application of in-plane uniaxial stress, enabling measurements of single domain electronic structure in the orthorhombic state. At low temperatures, our results clearly demonstrate an in-plane electronic anisotropy characterized by a large energy splitting of two orthogonal bands with dominant dxz and dyz character, which is consistent with anisotropy observed by other probes. For compositions x>0, for which the structural transition (TS) precedes the magnetic transition (TSDW), an anisotropic splitting is observed to develop above TSDW, indicating that it is specifically associated with TS. For unstressed crystals, the band splitting is observed close to TS, whereas for stressed crystals the splitting is observed to considerably higher temperatures, revealing the presence of a surprisingly large in-plane nematic susceptibility in the electronic structure.Comment: final version published in PNAS, including supplementary informatio

Ultrasound-assisted drying of orange peel in atmospheric freeze-dryer and convective dryer operated at moderate temperature

This is an Author's Accepted Manuscript of an article published in Ronaldo E. Mello, Alessia Fontana, Antonio Mulet, Jefferson Luiz, G. Correa & Juan A. Cárcel (2020) Ultrasound-assisted drying of orange peel in atmospheric freeze-dryer and convective dryer operated at moderate temperature, Drying Technology, 38:1-2, 259-267, DOI: 10.1080/07373937.2019.1645685 [copyright Taylor & Francis], available online at: http://www.tandfonline.com/10.1080/07373937.2019.1645685[EN] Atmospheric freeze-drying (AFD) at -10 degrees C and moderate temperature convective drying (MTD) at 50 degrees C without and with ultrasound application (20.5 kW/m(3)) were carried out. Alcohol insoluble residue (AIR) and its swelling capacity (SC), water retention capacity (WRC) and fat retention capacity (FRC) were measured in the dried product. Ultrasound significantly shortened the drying time in both processes, the intensification effect being more significant in atmospheric freeze-drying (57% and 27% reduction in atmospheric freeze-drying and convective drying, respectively). As regards AIR and WRC, no effect was observed of either the drying temperature or ultrasound application. On the contrary, SC was significantly lower in AFD samples. The FRC of MTD samples was similar to that of the fresh ones and higher than the values obtained for atmospheric freeze-dried samples. Therefore, convective drying at moderate temperature preserved the AIR properties better than atmospheric freeze-drying.The authors acknowledge the financial support of INIA-ERDF through project RTA2015-00060-C04-02. We are also grateful for the economic support of the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - Brasil (Capes)- Finance Code 001, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) and Fundacao de Amparo a Pesquisa de Minas Gerais (FAPEMIG).Mello, RE.; Fontana, A.; Mulet Pons, A.; Correa, J.; Carcel, JA. (2020). Ultrasound-assisted drying of orange peel in atmospheric freeze-dryer and convective dryer operated at moderate temperature. Drying Technology. 38(1-2):259-267. https://doi.org/10.1080/07373937.2019.1645685S259267381-2Freire, F. B., Atxutegi, A., Freire, F. B., Freire, J. T., Aguado, R., & Olazar, M. (2016). An adaptive lumped parameter cascade model for orange juice solid waste drying in spouted bed. Drying Technology, 35(5), 577-584. doi:10.1080/07373937.2016.1190937Tasirin, S. M., Puspasari, I., Sahalan, A. Z., Mokhtar, M., Ghani, M. K. A., & Yaakob, Z. (2014). Drying ofCitrus sinensisPeels in an Inert Fluidized Bed: Kinetics, Microbiological Activity, Vitamin C, and Limonene Determination. Drying Technology, 32(5), 497-508. doi:10.1080/07373937.2013.838782Zielinska, M., Sadowski, P., & Błaszczak, W. (2015). Combined hot air convective drying and microwave-vacuum drying of blueberries (Vaccinium corymbosumL.): Drying kinetics and quality characteristics. Drying Technology, 34(6), 665-684. doi:10.1080/07373937.2015.1070358Moreno, C., Brines, C., Mulet, A., Rosselló, C., & Cárcel, J. A. (2017). Antioxidant potential of atmospheric freeze-dried apples as affected by ultrasound application and sample surface. Drying Technology, 35(8), 957-968. doi:10.1080/07373937.2016.1256890Garcia-Perez, J. V., Ortuño, C., Puig, A., Carcel, J. A., & Perez-Munuera, I. (2011). Enhancement of Water Transport and Microstructural Changes Induced by High-Intensity Ultrasound Application on Orange Peel Drying. Food and Bioprocess Technology, 5(6), 2256-2265. doi:10.1007/s11947-011-0645-0Do Nascimento, E. M. G. C., Mulet, A., Ascheri, J. L. R., de Carvalho, C. W. P., & Cárcel, J. A. (2016). Effects of high-intensity ultrasound on drying kinetics and antioxidant properties of passion fruit peel. Journal of Food Engineering, 170, 108-118. doi:10.1016/j.jfoodeng.2015.09.015Martins, M. P., Cortés, E. J., Eim, V., Mulet, A., & Cárcel, J. A. (2018). Stabilization of apple peel by drying. Influence of temperature and ultrasound application on drying kinetics and product quality. Drying Technology, 37(5), 559-568. doi:10.1080/07373937.2018.1474476García-Pérez, J. V., Cárcel, J. A., Riera, E., & Mulet, A. (2009). Influence of the Applied Acoustic Energy on the Drying of Carrots and Lemon Peel. Drying Technology, 27(2), 281-287. doi:10.1080/07373930802606428Blasco, M., García-Pérez, J. V., Bon, J., Carreres, J. E., & Mulet, A. (2006). Effect of Blanching and Air Flow Rate on Turmeric Drying. Food Science and Technology International, 12(4), 315-323. doi:10.1177/1082013206067352Garau, M. C., Simal, S., Femenia, A., & Rosselló, C. (2006). Drying of orange skin: drying kinetics modelling and functional properties. Journal of Food Engineering, 75(2), 288-295. doi:10.1016/j.jfoodeng.2005.04.017Garau, M. C., Simal, S., Rosselló, C., & Femenia, A. (2007). Effect of air-drying temperature on physico-chemical properties of dietary fibre and antioxidant capacity of orange (Citrus aurantium v. Canoneta) by-products. Food Chemistry, 104(3), 1014-1024. doi:10.1016/j.foodchem.2007.01.009Beigi, M. (2015). Hot air drying of apple slices: dehydration characteristics and quality assessment. Heat and Mass Transfer, 52(8), 1435-1442. doi:10.1007/s00231-015-1646-8Santos, P. H. S., & Silva, M. A. (2008). Retention of Vitamin C in Drying Processes of Fruits and Vegetables—A Review. Drying Technology, 26(12), 1421-1437. doi:10.1080/07373930802458911Gallego-Juárez, J. A., Riera, E., de la Fuente Blanco, S., Rodríguez-Corral, G., Acosta-Aparicio, V. M., & Blanco, A. (2007). Application of High-Power Ultrasound for Dehydration of Vegetables: Processes and Devices. Drying Technology, 25(11), 1893-1901. doi:10.1080/07373930701677371Santacatalina, J. V., Ahmad-Qasem, M. H., Barrajón-Catalán, E., Micol, V., García-Pérez, J. V., & Cárcel, J. A. (2014). Use of Novel Drying Technologies to Improve the Retention of Infused Olive Leaf Polyphenols. Drying Technology, 33(9), 1051-1060. doi:10.1080/07373937.2014.982251Silva, V. M., & Viotto, L. A. (2010). Drying of sicilian lemon residue: influence of process variables on the evaluation of the dietary fiber produced. Ciência e Tecnologia de Alimentos, 30(2), 421-428. doi:10.1590/s0101-20612010000200020Garcia-Amezquita, L. E., Tejada-Ortigoza, V., Campanella, O. H., & Welti-Chanes, J. (2018). Influence of Drying Method on the Composition, Physicochemical Properties, and Prebiotic Potential of Dietary Fibre Concentrates from Fruit Peels. Journal of Food Quality, 2018, 1-11. doi:10.1155/2018/9105237Abou-Arab, E. A., Mahmoud, M. H., & Abu-Salem, F. M. (2017). Functional Properties of Citrus Peel as Affected by Drying Methods. American Journal of Food Technology, 12(3), 193-200. doi:10.3923/ajft.2017.193.200Ghanem Romdhane, N., Bonazzi, C., Kechaou, N., & Mihoubi, N. B. (2015). Effect of Air-Drying Temperature on Kinetics of Quality Attributes of Lemon (Citrus limoncv. lunari) Peels. Drying Technology, 33(13), 1581-1589. doi:10.1080/07373937.2015.101226

Statistical Data Assimilation: Formulation and Examples From Neurobiology

For the Research Topic Data Assimilation and Control: Theory and Applications in Life Sciences we first review the formulation of statistical data assimilation (SDA) and discuss algorithms for exploring variational approximations to the conditional expected values of biophysical aspects of functional neural circuits. Then we report on the application of SDA to (1) the exploration of properties of individual neurons in the HVC nucleus of the avian song system, and (2) characterizing individual neurons formulated as very large scale integration (VLSI) analog circuits with a goal of building functional, biophysically realistic, VLSI representations of functional nervous systems. Networks of neurons pose a substantially greater challenge, and we comment on formulating experiments to probe the properties, especially the functional connectivity, in song command circuits within HVC

An automated 3D-printed perfusion bioreactor combinable with pulsed electromagnetic field stimulators for bone tissue investigations

In bone tissue engineering research, bioreactors designed for replicating the main features of the complex native environment represent powerful investigation tools. Moreover, when equipped with automation, their use allows reducing user intervention and dependence, increasing reproducibility and the overall quality of the culture process. In this study, an automated uni-/bi-directional perfusion bioreactor combinable with pulsed electromagnetic field (PEMF) stimulation for culturing 3D bone tissue models is proposed. A user-friendly control unit automates the perfusion, minimizing the user dependency. Computational fluid dynamics simulations supported the culture chamber design and allowed the estimation of the shear stress values within the construct. Electromagnetic field simulations demonstrated that, in case of combination with a PEMF stimulator, the construct can be exposed to uniform magnetic fields. Preliminary biological tests on 3D bone tissue models showed that perfusion promotes the release of the early differentiation marker alkaline phosphatase. The histological analysis confirmed that perfusion favors cells to deposit more extracellular matrix (ECM) with respect to the static culture and revealed that bi-directional perfusion better promotes ECM deposition across the construct with respect to uni-directional perfusion. Lastly, the Real-time PCR results of 3D bone tissue models cultured under bi-directional perfusion without and with PEMF stimulation revealed that the only perfusion induced a similar to 40-fold up-regulation of the expression of the osteogenic gene collagen type I with respect to the static control, while a similar to 80-fold up-regulation was measured when perfusion was combined with PEMF stimulation, indicating a positive synergic proosteogenic effect of combined physical stimulations

Effect of Disorder on Fermi surface in Heavy Electron Systems

The Kondo lattice model with substitutional disorder is studied with attention to the size of the Fermi surface and the associated Dingle temperature. The model serves for understanding heavy-fermion Ce compounds alloyed with La according to substitution Ce{x}La{1-x}. The Fermi surface is identified from the steepest change of the momentum distribution of conduction electrons, and is derived at low enough temperature by the dynamical mean-field theory (DMFT) combined with the coherent potential approximation (CPA). The Fermi surface without magnetic field increases in size with decreasing x from x=1 (Ce end), and disappears at such x that gives the same number of localized spins as that of conduction electrons. From the opposite limit of x=0 (La end), the Fermi surface broadens quickly as x increases, but stays at the same position as that of the La end. With increasing magnetic field, a metamagnetic transition occurs, and the Fermi surface above the critical field changes continuously across the whole range of x. The Dingle temperature takes a maximum around x=0.5. Implication of the results to experimental observation is discussed.Comment: 5 pages, 5 figure