104 research outputs found
Effects of starch/polycaprolactone-based blends for spinal cord injury regeneration in neurons/glial cells viability and proliferation
Spinal cord injury (SCI) leads to drastic alterations on the quality of life of afflicted individuals. With the advent of Tissue Engineering and Regenerative Medicine where approaches combining biomaterials, cells and growth factors are used, one can envisage novel strategies that can adequately tackle this problem. The objective of this study was to evaluate a blend of starch with poly(Δ-caprolactone) (SPCL) aimed to be used for the development of scaffolds spinal cord injury (SCI) repair. SPCL linear parallel filaments were deposited on polystyrene coverslips and assays were carried out using primary cultures of hippocampal neurons and glial cells. Light and fluorescence microscopy observations revealed that both cell populations were not negatively affected by the SPCL-based biomaterial. MTS and total protein quantification indicated that both cell viability and proliferation rates were similar to controls. Both neurons and astrocytes occasionally contacted the surface of SPCL filaments through their dendrites and cytoplasmatic processes, respectively, while microglial cells were unable to do so. Using single cell [Ca2+ ]i imaging, hippocampal neurons were observed growing within the patterned channels and were functional as assessed by the response to a 30 mM KCl stimulus. The present data demonstrated that SPCL-based blends are potentially suitable for the development of scaffolds in SCI regenerative medicine.Portuguese Foundation for Science and Technology through funds from POCTI and/or FEDER programs (Funding to ICVS, 3B's Research Group and post doctoral fellowship to A.J. Salgado-SFRH/BPD/17595/2004)
Magnetic Catalysis: A Review
We give an overview of the magnetic catalysis phenomenon. In the framework of
quantum field theory, magnetic catalysis is broadly defined as an enhancement
of dynamical symmetry breaking by an external magnetic field. We start from a
brief discussion of spontaneous symmetry breaking and the role of a magnetic
field in its a dynamics. This is followed by a detailed presentation of the
essential features of the phenomenon. In particular, we emphasize that the
dimensional reduction plays a profound role in the pairing dynamics in a
magnetic field. Using the general nature of underlying physics and its
robustness with respect to interaction types and model content, we argue that
magnetic catalysis is a universal and model-independent phenomenon. In support
of this claim, we show how magnetic catalysis is realized in various models
with short-range and long-range interactions. We argue that the general nature
of the phenomenon implies a wide range of potential applications: from certain
types of solid state systems to models in cosmology, particle and nuclear
physics. We finish the review with general remarks about magnetic catalysis and
an outlook for future research.Comment: 37 pages, to appear in Lect. Notes Phys. "Strongly interacting matter
in magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A.
Schmitt, H.-U. Yee. Version 2: references adde
Electromagnetic superconductivity of vacuum induced by strong magnetic field
The quantum vacuum may become an electromagnetic superconductor in the
presence of a strong external magnetic field of the order of 10^{16} Tesla. The
magnetic field of the required strength (and even stronger) is expected to be
generated for a short time in ultraperipheral collisions of heavy ions at the
Large Hadron Collider. The superconducting properties of the new phase appear
as a result of a magnetic-field-assisted condensation of quark-antiquark pairs
with quantum numbers of electrically charged rho mesons. We discuss
similarities and differences between the suggested superconducting state of the
quantum vacuum, a conventional superconductivity and the Schwinger pair
creation. We argue qualitatively and quantitatively why the superconducting
state should be a natural ground state of the vacuum at the sufficiently strong
magnetic field. We demonstrate the existence of the superconducting phase using
both the Nambu-Jona-Lasinio model and an effective bosonic model based on the
vector meson dominance (the rho-meson electrodynamics). We discuss various
properties of the new phase such as absence of the Meissner effect, anisotropy
of superconductivity, spatial inhomogeneity of ground state, emergence of a
neutral superfluid component in the ground state and presence of new
topological vortices in the quark-antiquark condensates.Comment: 37 pages, 14 figures, to appear in Lect. Notes Phys. "Strongly
interacting matter in magnetic fields" (Springer), edited by D. Kharzeev, K.
Landsteiner, A. Schmitt, H.-U. Ye
Estimation of transpiration of the 'Valencia' orange young plant using thermal dissipation probe method
Efeito da Gliricidia sepium sobre nutrientes do solo, microclima e produtividade do milho em sistema agroflorestal no Agreste Paraibano.
Gliricidia sepium Ă© uma leguminosa arbĂłrea que tem sido utilizada em sistemas em alĂ©ias no semi-ĂĄrido nordestino por apresentar bom desenvolvimento em condiçÔes de estresse hĂdrico. Entretanto, hĂĄ pouca informação disponĂvel sobre o efeito da introdução dessa espĂ©cie nos agroecossistemas da regiĂŁo. No presente estudo, objetivou-se avaliar a influĂȘncia da distĂąncia de plantas de Gliricidia sepium sobre caracterĂsticas da cultura do milho e do solo e microclima no Agreste Paraibano. O estudo foi realizado no municĂpio de Esperança (PB), em ĂĄrea de 0,5 ha, onde, em 1996, foram plantadas fileiras de G. sepium espaçadas 6 m entre si e com 1 m entre as ĂĄrvores. Nesta ĂĄrea, em 2002, foram delimitadas quatro parcelas de 6 x 8 m e, em cada parcela, foi estabelecido um transeto perpendicular Ă s fileiras de ĂĄrvores com trĂȘs posiçÔes de amostragem: (1) nas fileiras de ĂĄrvores (0 m); (2) a 1 m das fileiras de ĂĄrvores, e (3) a 3 m de distĂąncia das fileiras de ĂĄrvores. O delineamento experimental utilizado foi em blocos casualizados com quatro repetiçÔes. A massa seca de folhedo caĂdo embaixo da fileira de ĂĄrvores foi de 1.390 kg ha-1 e diminuiu, gradativamente, para 270 kg ha-1 a 3 m de distĂąncia das ĂĄrvores. As concentraçÔes de P, K e matĂ©ria orgĂąnica leve (MOL) embaixo das ĂĄrvores foram maiores do que a 1 e 3 m de distĂąncia das fileiras. As mĂ©dias mensais das temperaturas mĂnimas do ar e do solo embaixo e a 3 m das ĂĄrvores foram similares. Entretanto, as mĂ©dias mensais das temperaturas mĂĄximas do solo e do ar foram de 6 e 2 °C mais altas a 3 m das ĂĄrvores, respectivamente, ao longo do perĂodo de estudo. A umidade do solo foi significativamente menor embaixo das ĂĄrvores do que a 1 e 3 m de distĂąncia. O milho produziu mais grĂŁos e palha e acumulou mais nutrientes nas posiçÔes mais prĂłximas das fileiras de G. sepium
K'Mudku A-type magmatism in the southernmost Guyana Shield, central-north Amazon Craton (Brazil): the case of Pedra do GaviĂŁo syenogranite
Genetic differentiation in the populations of red piranha, Pygocentrus nattereri Kner (1860) (Characiformes: Serrasalminae), from the river basins of northeastern Brazil
Zooterapia amazĂŽnica: uso de gordura de sucuri ( Eunectes murinus ) como cicatrizante natural
Zootherapy (the use of the therapeutic potential of animals) is at least 6,000 years old, and has been kept active throughout generations until modern days. Animal fat is commonly used in the zootherapeutic folk medicine from South America, specially the green anaconda's fat, which is widely promoted as a natural medicine to treat wounds, even though there is no scientific evidence showing its efficacy. In this study we compared the total healing time and the proportional daily reduction of dorsal epithelial incisions in adult male Wistar rats treated with nitrofural (a commercial cicatrizing ointment) and with anaconda fat. We applied the treatments every two days and measured the incision diameter daily, during ten consecutive days. Differences among the groups in the total healing time and in the proportional daily reduction of the incision consistently showed that the fat-based treatment resulted in a faster healing process compared to the commercial ointment tested. The literature suggests that the efficacy of animal fat on healing may be primarily related to the presence of fatty acids, which have been widely demonstrated to be important for biochemical reactions involved in healing processes. Our findings are widely socially relevant, considering that traditional Amazonian communities that use anaconda fat in folk medicine do not have easy access to pharmacies and hospitals.PrĂĄticas ancestrais de zooterapia (uso das potencialidades terapĂȘuticas da fauna) existem hĂĄ pelo menos 6000 anos, e tĂȘm sido mantidas ao longo de geraçÔes atĂ© os tempos modernos. Gordura de animais Ă© comumente utilizada na zooterapia tradicional da AmĂ©rica do Sul, e a gordura de serpentes sucuris Ă© amplamente comercializada como cicatrizante natural, embora nĂŁo existam evidĂȘncias cientĂficas que mostrem sua eficĂĄcia terapĂȘutica. Neste estudo comparamos o tempo de cicatrização epitelial total e a redução proporcional diĂĄria de uma incisĂŁo dorsal em ratos Wistar machos adultos, entre um grupo controle, um grupo tratado com nitrofural (uma pomada cicatrizante comercial) e um grupo tratado com gordura de sucuri. NĂłs aplicamos os tratamentos a cada dois dias e medimos o diĂąmetro da incisĂŁo diariamente por dez dias consecutivos. Diferenças entre os grupos no tempo de cicatrização total e na redução proporcional diĂĄria da incisĂŁo consistentemente mostraram que gordura de sucuri teve ação cicatrizante mais eficiente que a pomada comercial testada. A literatura sugere que a eficĂĄcia de gordura animal em processos de cicatrização pode estar principalmente relacionada Ă presença de ĂĄcidos graxos, os quais tĂȘm sido amplamente demonstrados como importantes para reaçÔes bioquĂmicas envolvidas em processos de cicatrização. Os resultados tĂȘm ampla relevĂąncia social, considerando que as comunidades tradicionais amazĂŽnicas que utilizam a gordura de sucuris como zooterĂĄpico nĂŁo tĂȘm acesso fĂĄcil a farmĂĄcias e hospitais
Team dynamics in emergency surgery teams: results from a first international survey
Background: Emergency surgery represents a unique context. Trauma teams are often multidisciplinary and need to operate under extreme stress and time constraints, sometimes with no awareness of the trauma\u2019s causes or the patient\u2019s personal and clinical information. In this perspective, the dynamics of how trauma teams function is fundamental to ensuring the best performance and outcomes. Methods: An online survey was conducted among the World Society of Emergency Surgery members in early 2021. 402 fully filled questionnaires on the topics of knowledge translation dynamics and tools, non-technical skills, and difficulties in teamwork were collected. Data were analyzed using the software R, and reported following the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). Results: Findings highlight how several surgeons are still unsure about the meaning and potential of knowledge translation and its mechanisms. Tools like training, clinical guidelines, and non-technical skills are recognized and used in clinical practice. Others, like patients\u2019 and stakeholders\u2019 engagement, are hardly implemented, despite their increasing importance in the modern healthcare scenario. Several difficulties in working as a team are described, including the lack of time, communication, training, trust, and ego. Discussion: Scientific societies should take the lead in offering training and support about the abovementioned topics. Dedicated educational initiatives, practical cases and experiences, workshops and symposia may allow mitigating the difficulties highlighted by the survey\u2019s participants, boosting the performance of emergency teams. Additional investigation of the survey results and its characteristics may lead to more further specific suggestions and potential solutions
Measurement of the CP-violating phase Ï in the BâJ/Ï Ï(1020) âÎŒâșÎŒâ»KâșKâ» channel in proton-proton collisions at âs = 13 TeV
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