Crossover between the Dense Electron-Hole Phase and the BCS Excitonic Phase in Quantum Dots

Second order perturbation theory and a Lipkin-Nogami scheme combined with an exact Monte Carlo projection after variation are applied to compute the ground-state energy of $6\le N\le 210$ electron-hole pairs confined in a parabolic two-dimensional quantum dot. The energy shows nice scaling properties as N or the confinement strength is varied. A crossover from the high-density electron-hole phase to the BCS excitonic phase is found at a density which is roughly four times the close-packing density of excitons.Comment: Improved variational and projection calculations. 17 pages, 3 ps figures. Accepted for publication in Int. J. Mod. Phys.

Formación de valores desde una concepción axiológica-martiana en profesionales de la Cultura Física

Introducción: la educación en valores es una problemática que preocupa, y es objeto de análisis de políticos, especialistas y educadores de diferentes países, independientemente del régimen social existente; vinculado a la propia existencia del ser humano. El estudio de la obra martiana en nuestro ámbito sociocultural es una necesidad impostergable, por la frescura y actualidad que sus enseñanzas reportan, su empleo adecuado y oportuno, por parte del maestro en la dirección del proceso educativo. Objetivo: ayudar a reflexionar de forma sistematizada acerca de la formación de valores desde una concepción axiológica en los profesionales de la Cultura Física y el Deporte como uno de los grandes retos que tiene la sociedad cubana. Materiales y métodos: nos hemos apoyado en una investigación con enfoque cualitativo, descriptiva y no experimental, a través del análisis-síntesis, la inducción deducción y la recopilación de información a través del empleo del motor de búsqueda de Google. Resultados: los sustentos teóricos utilizados en esta investigación posibilitaron reflexionar desde una mirada axiológica acerca de la formación de valores en los futuros profesionales de la Cultura Física y el Deporte como expresión de las necesidades e intereses prácticos del ser humano y la socialización en el proceso de individualización desde las dinámicas grupales como manifestación concreta de la Cultura Física y el Deporte masificado. Conclusiones: la formación de valores en los futuros profesionales no se puede formar por decretos, ni sobre la base de la inculcación de modelos, estos son valiosos, pero deben asumirse con una mentalidad dialéctica, flexible, inclusiva, y contextualizada

Far infrared giant dipole resonances in neutral quantum dots

A resonance behaviour of the far infrared absorption probability at a frequency \sim N^{1/4} is predicted for clusters of N electron-hole pairs (2\le N\le 110) confined in disk-shaped quantum dots. For radially symmetric dots, the absorption is dominated by a Giant Dipole Resonance, which accounts for more than 98 % of the energy-weighted photoabsorption sum rule.Comment: final versio

Inducción de callos y regeneración de plantas en Tectona grandis L.

The rescue of commercial species is a priority for biotechnology to increase multiplication rate and develop reforestation. Such programmes can be carried out simultaneously with the development of the country to mantain the ecosystem natural equilibrium. Teak (Tectona grandis L.) is a forest tree of high commercial and ecological value because of its rapid growth and wood quality. Teak is a specie with problems in the propagation as a result of its high genetic variability. For this reason, alternatives to produce propagules have been developed. With the aim to obtain plants regeneration from this were used shoot tips and flowers immature of mature tree explants and cotyledons from seed. Different thidiazuron concentrations was tested for callus formation and cytokinins for plants regeneration. Nodular calli was obtained from shoot tips, cotyledons and flowers immature. The shoots regeneration was achieved in calli from shoot tips.Key words: organogenesis, teak , tissue cultureEl trabajo con especies de interés comercial constituye una de las líneas prioritarias de la biotecnología, como herramienta básica en el apoyo al mejoramiento de árboles élites. La teca (Tectona grandis L.), es un forestal de alto interés comercial y ecológico por su rápido crecimiento y la calidad de su madera. Es una especie que tiene graves problemas para la propagación por la alta variabilidad genética de las plantas producidas por semillas. El objetivo de este trabajo fue establecer una metodología para la regeneración de plantas de esta especie forestal con vistas a utilizarla en los programas de mejoramiento genético. Se utilizaron como explantes ápices y botones florales de árboles adultos y cotiledones de semillas. Las semillas se desinfectaron con HgCl2 al 0.2% durante 10 minutos. para el establecimiento in vitro de los cotiledones. Se evaluaron diferentes concentraciones de Thidiazuron en los explantes antes señalados, con el objetivo de lograr la formación de callos y diferentes niveles de Bencilaminopurina y Kinetina para la emisión de brotes. Se logró la formación de callos en todos los explantes empleados. Se formaron callos nodulares a partir de los segmentos de ápices, cotiledones y botones florales y se regeneraron brotes en los callos provenientes de ápices.Palabras clave: cultivo de tejidos, organogénesis, tec

Deciphering the quality of SARS-CoV-2 specific T-cell response associated with disease severity, immune memory and heterologous response

SARS-CoV-2 specific T-cell response has been associated with disease severity, immune memory and heterologous response to endemic coronaviruses. However, an integrative approach combining a comprehensive analysis of the quality of SARS-CoV-2 specific T-cell response with antibody levels in these three scenarios is needed. In the present study, we found that, in acute infection, while mild disease was associated with high T-cell polyfunctionality biased to IL-2 production and inversely correlated with anti-S IgG levels, combinations only including IFN-γ with the absence of perforin production predominated in severe disease. Seven months after infection, both non-hospitalised and previously hospitalised patients presented robust anti-S IgG levels and SARS-CoV-2 specific T-cell response. In addition, only previously hospitalised patients showed a T-cell exhaustion profile. Finally, combinations including IL-2 in response to S protein of endemic coronaviruses were the ones associated with SARS-CoV-2 S-specific T-cell response in pre-COVID-19 healthy donors’ samples. These results could have implications for protective immunity against SARS-CoV-2 and recurrent COVID-19 and may help for the design of new prototypes and boosting vaccine strategies

Plasma Rich in Growth Factors (PRGF) in Transepithelial Photorefractive Keratectomy (TPRK)

To evaluate the usage of plasma rich in growth factor (PRGF) in transepithelial photorefractive keratectomy (TPRK) in low and moderate myopia, patients who underwent myopic and astigmatism TPRK with PRGF were involved in this retrospective, observational study. Subjects underwent a surgical procedure between February 2019 and June 2019. A three-month follow-up was recorded. Pain score was assessed with a visual analogue scale (0–10) and re-epithelialization time recorded. A total of 48 eyes from 24 patients were recruited. Mean uncorrected distance visual acuity (UDVA) was 20/20.31 (0.00 ± 0.02 LogMAR). A total of 98% of eyes did not change corrected distance visual acuity (CDVA) lines. Two percent of eyes lost one line of CDVA. Preoperative spherical equivalent was −2.67 ± 1.37 D and after three months changed to −0.21 ± 0.34 D, and 2% of eyes changed 0.50 D or more between one and three months. Pain score was 3.29 ± 0.61 (3 to 6) score points at day one and 0.08 ± 0.27 score points at day seven. Finally, re-epithelialization time was 2.50 ± 1.20 days. PRGF addition to conventional refractive treatment such as TPRK seems to alleviate immediate postoperative pain and positively contribute to corneal re-epithelization time.publishersversionPeer reviewe

Acercamiento a la producción científica sobre cirugía publicada en las Revistas Científicas Estudiantiles Cubanas, 2014-2018

Introducción: el análisis de la producción científica sobre un área temática, permite determinar elementos importantes para la toma de decisiones, así como para mejorar los aportes realizados a la ciencia.  Objetivo: caracterizar la productividad científica del área cirugía publicada en Revistas Científicas Estudiantiles Cubanas en el periodo 2014-2018.Método: se realizó un estudio bibliométrico de la producción científica estudiantil sobre cirugía publicada en las Revistas Científicas Estudiantiles cubanas. La muestra quedó constituida por 22 artículos. Se empleó frecuencia absoluta y relativa porcentual, el índice de Price y número de citas corregidas.Resultados: el 50 % de los artículos se publicaron en Universidad Médica Pinareña, la mayor producción fue en el 2018 (31,82 %). Existió un predominio de artículos con 4 autores (68,18 %). La rama de la cirugía predominante fue la cirugía general (36,36 %). Se encontró una media de 14,77 referencias por artículo. El índice de Price en los artículos osciló entre 0,45 y 0,76. El 50 % de la producción proviene de Pinar del Río. Solo 3 artículos recibieron citas predominando las Presentaciones de caso.Conclusiones: la productividad científica, así como el índice de citaciones fue baja. La cirugía general aportó el mayor número de artículos. Se encontró predominio de autoría múltiple, donde la revista Universidad Médica Pinareña publicó el mayor número de artículos

Epidemiological and clinical variables’ behavior in patients with stroke of Villa Clara

Background: cerebrovascular disease represents the most common health problem related to neurological care, it is important to study it in different contexts and from different approaches.Objective: to describe epidemiological and clinical variables’ behavior in patients admitted for stroke.Methods: descriptive and cross-sectional study, carried out in Arnaldo Milián Castro Hospital’s Neurology service from Villa Clara, Cuba, which included all patients with a clinical diagnosis of cardioembolic or atherothrombotic stroke, admitted to the ward during 2019. The information was obtained from the medical records stored in the Hospital Archive; and it was processed in the statistical package SPSS. v. 21. A descriptive statistical analysis was applied, in a frequency distribution.Results: female patients predominated (51.6%). There was a higher incidence in men older than 79 years (47.7%), and in women older than 70 (86.0%). In 67.3% the cardioembolic cause was demonstrated. Arterial hypertension was the main associated risk factor (83.6%). The motor defect was observed as the most frequent clinical finding on admission (96.7%). Hemorrhagic transformation of the infarct and nosocomial bronchopneumonia were identified as the main neurological and non-neurological complications, respectively. Patients discharged alive prevailed (68.6%).Conclusions: ischemic strokes are more frequent in elderly patients; early identification and timely management of the established disease can largely prevent the appearance of complications, and consequently death.</p

Response-adapted treatment with rituximab, bendamustine, mitoxantrone, and dexamethasone followed by rituximab maintenance in patients with relapsed or refractory follicular lymphoma after first-line immunochemotherapy: Results of the RBMDGELTAMO08 phase II trial

Background Consensus is lacking regarding the optimal salvage therapy for patients with follicular lymphoma who relapse after or are refractory to immunochemotherapy. Methods This phase II trial evaluated the efficacy and safety of response-adapted therapy with rituximab, bendamustine, mitoxantrone, and dexamethasone (RBMD) in follicular lymphoma patients who relapsed after or were refractory to first-line immunochemotherapy. Sixty patients received three treatment cycles, and depending on their response received an additional one (complete/unconfirmed complete response) or three (partial response) cycles. Patients who responded to induction received rituximab maintenance therapy for 2 years. Results Thirty-three (55%) and 42 (70%) patients achieved complete/unconfirmed complete response after three cycles and on completing induction therapy (4-6 cycles), respectively (final overall response rate, 88.3%). Median progression-free survival was 56.4 months (median follow-up, 28.3 months; 95% CI, 15.6-51.2). Overall survival was not reached. Progression-free survival did not differ between patients who received four vs six cycles (P = .6665), nor between patients who did/did not receive rituximab maintenance after first-line therapy (P = .5790). Median progression-free survival in the 10 refractory patients was 25.5 months (95% CI, 0.6-N/A) and was longer in patients who had shown progression of disease after 24 months of first-line therapy (median, 56.4 months; 95% CI, 19.8-56.4) than in those who showed early progression (median, 42.31 months; 95% CI, 24.41-NA) (P = .4258). Thirty-six (60%) patients had grade 3/4 neutropenia. Grade 3/4 febrile neutropenia and infection were recorded during induction (4/60 [6.7%] and 5/60 [8.3%] patients, respectively) and maintenance (2/43 [4.5%] and 4/43 [9.1%] patients, respectively). Conclusions This response-adapted treatment with RBMD followed by rituximab maintenance is an effective and well-tolerated salvage treatment for relapsed/refractory follicular lymphoma following first-line immunochemotherapy

Disaturated-phosphatidylcholine and Surfactant protein-B turnover in human acute lung injury and in control patients

<p>Abstract</p> <p>Background</p> <p>Patients with Adult Respiratory Distress Syndrome (ARDS) and Acute Lung Injury (ALI) have low concentrations of disaturated-phosphatidylcholine and surfactant protein-B in bronchoalveolar lavage fluid. No information is available on their turnover.</p> <p>Objectives</p> <p>To analyze disaturated-phosphatidylcholine and surfactant protein-B turnover in patients with ARDS/ALI and in human adults with normal lungs (controls).</p> <p>Methods</p> <p>²H₂O as precursor of disaturated-phosphatidylcholine-palmitate and 1¹³C-Leucine as precursor of surfactant protein-B were administered intravenously to 12 patients with ARDS/ALI and to 8 controls. Disaturated-phosphatidylcholine and surfactant protein-B were isolated from serial tracheal aspirates, and their fractional synthetic rate was derived from the ²H and ¹³C enrichment curves, obtained by gas chromatography mass spectrometry. Disaturated-phosphatidylcholine, surfactant protein-B, and protein concentrations in tracheal aspirates were also measured.</p> <p>Results</p> <p>1) Surfactant protein-B turned over at faster rate than disaturated-phosphatidylcholine both in ARDS/ALI patients and in controls. 2) In patients with ARDS/ALI the fractional synthesis rate of disaturated-phosphatidylcholine was 3.1 times higher than in controls (p < 0.01), while the fractional synthesis rate of surfactant protein-B was not different. 3) In ARDS/ALI patients the concentrations of disaturated-phosphatidylcholine and surfactant protein-B in tracheal aspirates were markedly and significantly reduced (17% and 40% of the control values respectively).</p> <p>Conclusions</p> <p>1) Disaturated-phosphatidylcholine and surfactant protein-B have a different turnover both in healthy and diseased lungs. 2) In ARDS/ALI the synthesis of these two surfactant components may be differently regulated.</p