Very-high-frequency oscillations in the main peak of a magnetar giant flare.

Magnetars are strongly magnetized, isolated neutron stars1-3 with magnetic fields up to around 1015 gauss, luminosities of approximately 1031-1036 ergs per second and rotation periods of about 0.3-12.0 s. Very energetic giant flares from galactic magnetars (peak luminosities of 1044-1047 ergs per second, lasting approximately 0.1 s) have been detected in hard X-rays and soft γ-rays4, and only one has been detected from outside our galaxy5. During such giant flares, quasi-periodic oscillations (QPOs) with low (less than 150 hertz) and high (greater than 500 hertz) frequencies have been observed6-9, but their statistical significance has been questioned10. High-frequency QPOs have been seen only during the tail phase of the flare9. Here we report the observation of two broad QPOs at approximately 2,132 hertz and 4,250 hertz in the main peak of a giant γ-ray flare11 in the direction of the NGC 253 galaxy12-17, disappearing after 3.5 milliseconds. The flare was detected on 15 April 2020 by the Atmosphere-Space Interactions Monitor instrument18,19 aboard the International Space Station, which was the only instrument that recorded the main burst phase (0.8-3.2 milliseconds) in the full energy range (50 × 103 to 40 × 106 electronvolts) without suffering from saturation effects such as deadtime and pile-up. Along with sudden spectral variations, these extremely high-frequency oscillations in the burst peak are a crucial component that will aid our understanding of magnetar giant flares.

The shell effect on the room temperature photoluminescence from ZnO/MgO core/shell nanowires: exciton-phonon coupling and strain.

The room temperature photoluminescence from ZnO/MgO core/shell nanowires (NWs) grown by a simple two-step vapor transport method was studied for various MgO shell widths (w). Two distinct effects induced by the MgO shell were clearly identified. The first one, related to the ZnO/MgO interface formation, is evidenced by strong enhancements of the zero-phonon and first phonon replica of the excitonic emission, which are accompanied by a total suppression of its second phonon replica. This effect can be explained by the reduction of the band bending within the ZnO NW core that follows the removal of atmospheric adsorbates and associated surface traps during the MgO growth process on one hand, and a reduced exciton-phonon coupling as a result of the mechanical stabilization of the outermost ZnO NW monolayers by the MgO shell on the other hand. The second effect is the gradual increase of the excitonic emission and decrease in the defect related emission by up to two and one orders of magnitude, respectively, when w is increased in the ∼3-17 nm range. Uniaxial strain build-up within the ZnO NW core with increasing w, as detected by x-ray diffraction measurements, and photocarrier tunneling escape from the ZnO core through the MgO shell enabled by defect-states are proposed as possible mechanisms involved in this effect. These findings are expected to be of key significance for the efficient design and fabrication of ZnO/MgO NW heterostructures and devices.

Glucose biosensor based on functionalized ZnO nanowire/graphite films dispersed on a Pt electrode.

We present a glucose biosensor based on ZnO nanowire self-sustained films grown on compacted graphite flakes by the vapor transport method. Nanowire/graphite films were fragmented in water, filtered to form a colloidal suspension, subsequently functionalized with glucose oxidase and finally transferred to a metal electrode (Pt). The obtained devices were evaluated using scanning electron microscopy, energy-dispersive x-ray spectroscopy, cyclic voltammetry and chronoamperometry. The electrochemical responses of the devices were determined in buffer solutions with successive glucose aggregates using a tripolar electrode system. The nanostructured biosensors showed excellent analytical performance, with linear response to glucose concentrations, high sensitivity of up to ≈17 µA cm(-2) mM(-1) in the 0.03-1.52 mM glucose concentration range, relatively low Michaelis-Menten constant, excellent reproducibility and a fast response. The detection limits are more than an order of magnitude lower than those achievable in commercial biosensors for glucose control, which is promising for the development of glucose monitoring methods that do not require blood extraction from potentially diabetic patients. The strong detection enhancements provided by the functionalized nanostructures are much larger than the electrode surface-area increase and are discussed in terms of the physical and chemical mechanisms involved in the detection and transduction processes.

Nonlinear excitation of polariton cavity modes in ZnO single nanocombs.

Tunable second harmonic (SH) polaritons have been efficiently generated in ZnO nanocombs, when the material is excited close to half of the band-gap. The nonlinear signal couples to the nanocavity modes, and, as a result, Fabry-Pérot resonances with high Q factors of about 500 are detected. Due to the low effective volume of the confined modes, matter-light interaction is very much enhanced. This effect lowers the velocity of the SH polariton in the material by 50 times, and increases the SH confinement inside the nanocavity due to this higher refractive index. We also show that the SH phase-matching condition is achieved through LO-phonon mediation. Finally, birrefringence of the crystal produces a strong SH intensity dependence on the input polarization, with a high polarization contrast, which could be used as a mechanism for light switching in the nanoscale.

Enhanced optical properties and (Zn, Mg) interdiffusion in vapour transport grown ZnO/MgO core/shell nanowires.

ZnO/MgO (core/shell) nanowires (NWs) grown by a two-step vapour transport method under different MgO shell growth conditions are examined by x-ray diffraction, photoluminescence (PL) excitation and temperature (10-300 K) dependent PL. The excitonic-to-defect PL ratio is increased by more than two orders of magnitude in the core/shell as compared to bare ZnO NWs. Concomitantly, a strong depression of the PL thermal quenching, most particularly for the visible part of the PL spectrum, occurs. Using a semi-quantitative model, results are interpreted as a strong radiative to non-radiative lifetime ratio reduction due to defect passivation at the ZnO NW walls and photocarrier confinement within the ZnO core by the MgO shell. These beneficial effects are, however, significantly weakened when metal interdiffusion across the core/shell interface is favoured during the shell growth. Non-radiative recombination lifetime in the sample with sharp core/shell interface is described by a single activation energy of 15 meV (bound exciton release). For interdiffused cases and bare ZnO an additional activation energy of 60 meV (free exciton breakup) is observed.

DiI labeling of human adipose-derived stem cells: evaluation of DNA damage, toxicity and functional impairment.

INTRODUCTION: Adipose tissue-derived stem cells (ASCs) have become the primary focus of tissue engineering research. To understand their functions and behavior in in vitro and in vivo models, it is mandatory to track the implanted cells and distinguish them from the resident or host cells. A common labeling method is the use of fluorescent dyes, e.g. the lipophilic carbocyanine dye, DiI. This study aimed to analyze potential DNA damage, toxicity and impairment of the functional properties of human ASCs after labeling with DiI. METHODS: Cytotoxicity was measured using the MTT assay and DNA damage was determined by means of the comet assay. Potential apoptotic effects were determined using the annexin V-propidium iodide test. Differentiation potential was evaluated by trilineage differentiation procedures in labeled and unlabeled ASCs. Proliferation as well as migration capability was analyzed, and the duration and stability of DiI labeling in ASCs during in vitro expansion was observed over a period of 35 days. RESULTS: DiI labeling did not cause genotoxic effects 15, or 30 min or 24 h after the labeling procedure, and there were no cytotoxic effects until 72 h afterwards. No impairment of proliferation or migration capability or differentiation potential could be determined. However, after 35 days, only 37% of labeled cells could be detected using the fluorescence microscope, which indicates a decrease in staining stability during in vitro expansion. CONCLUSION: DiI is a convenient method for ASCs labeling which causes no toxic effects and does not impair the proliferation, migration or differentiation potential of ASCs after the labeling procedure.

Climate change and nutrition: creating a climate for nutrition security.

BACKGROUND: Climate change further exacerbates the enormous existing burden of undernutrition. It affects food and nutrition security and undermines current efforts to reduce hunger and promote nutrition. Undernutrition in turn undermines climate resilience and the coping strategies of vulnerable populations. OBJECTIVES: The objectives of this paper are to identify and undertake a cross-sectoral analysis of the impacts of climate change on nutrition security and the existing mechanisms, strategies, and policies to address them. METHODS: A cross-sectoral analysis of the impacts of climate change on nutrition security and the mechanisms and policies to address them was guided by an analytical framework focused on the three 'underlying causes' of undernutrition: 1) household food access, 2) maternal and child care and feeding practices, 3) environmental health and health access. The analytical framework includes the interactions of the three underlying causes of undernutrition with climate change,vulnerability, adaptation and mitigation. RESULTS: Within broad efforts on climate change mitigation and adaptation and climate-resilient development, a combination of nutrition-sensitive adaptation and mitigation measures, climate-resilient and nutrition-sensitive agricultural development, social protection, improved maternal and child care and health, nutrition-sensitive risk reduction and management, community development measures, nutrition-smart investments, increased policy coherence, and institutional and cross-sectoral collaboration are proposed as a means to address the impacts of climate change to food and nutrition security. This paper proposes policy directions to address nutrition in the climate change agenda and recommendations for consideration by the UN Framework Convention on Climate Change (UNFCCC). CONCLUSIONS: Nutrition and health stakeholders need to be engaged in key climate change adaptation and mitigation initiatives, including science-based assessment by the Intergovernmental Panel on Climate Change (IPCC), and policies and actions formulated by the UN Framework Convention on Climate Change (UNFCCC). Improved multi-sectoral coordination and political will is required to integrate nutrition-sensitive actions into climate-resilient sustainable development efforts in the UNFCCC work and in the post 2015 development agenda. Placing human rights at the center of strategies to mitigate and adapt to the impacts of climate change and international solidarity is essential to advance sustainable development and to create a climate for nutrition security.

Characteristics and treatment of nonagenarian patients with vascular disease admitted to internal medicine services. NONAVASC-2 registry.

INTRODUCTION: Vascular disease (VD) is the most frequent cause of morbidity and mortality and its prevalence increases with age. Old patients are not included in studies on VD, their characteristics and treatments being unknown. OBJECTIVE: Know the clinical characteristics of nonagenarian patients hospitalized in Internal Medicine services with a diagnosis of established VD and the adequacy of their pharmacological management. MATERIAL AND METHODS: The NONAVASC-2 registry is an observational, prospective, multicentre study. Hospitalized patients for any cause were included. Data collection was carried out through an anonymous online database with sociodemographic, clinical, analytical, therapeutic and evolutionary parameters. RESULTS: One thousand forty-nine patients with a mean age of 93.14 years (57.8% women) were included. The prevalence of risk factors and VD was high: hypertension (84.9%), dyslipidemia (50.9%) and diabetes mellitus (29.4%). 33.4% presented severe-total dependency. 82.9% received antithrombotic treatment (53.7% antiplatelets, 25.4% anticoagulation and 3.8% double therapy). Only 38.2% received statins. The percentage of severe dependence (39.2% vs 24.1%; p = 0.00) and severe cognitive impairment (30.8% vs 13.8%; p = 0.00) was significantly higher among patients who did not receive them. 19% died during admission. CONCLUSIONS: Nonagenarian patients with VD present high comorbidity, dependence and mortality. Despite being in secondary prevention, 17% did not receive antithrombotics and only 38% received statins. The underprescription is conditioned, among other factors, by the functional status. More studies are necessary to determine the impact of this issue on their prognosis.

Adverse Drug Reactions during COVID-19 Treatment: A Comprehensive Analysis Focused on Hospitalized Patients, with the Use of a Survey in Cuba in 2020.

Aims: To evaluate the prevalence and type of adverse drug reactions (ADRs), together with associated risk factors, among Cuban COVID-19 patients treated with chloroquine (CQ), lopinavir/ritonavir (LPV/r), or interferon α2b (IFN α2b), according to the Cuban protocol. Materials and Methods: A prospective descriptive analysis of ADRs was performed on 200 COVID-19 patients who were admitted consecutively to three hospitals in Havana and Pinar del Río from April to July 2020. Information on demographics, ADRs, outcomes, behavioral, and health-related factors was collected using a validated questionnaire and clinical records. Each potential ADR case was assessed for causality based on the WHO-UMC algorithm, concomitant drug influences, and the presence of any drug-drug interactions (DDI). Results: The total frequency of ADRs was 55%, with predominantly gastrointestinal disorders and general symptoms (23% vs 20%). 95.1% of ADRs occurred within 10 days after treatment and 42 potential DDI in 55.5% of patients (61/110) were observed. The prevalence of ADRs was: 44%, 30.4%, and 26.4% for IFN α2b, LPV/r, and CQ, respectively. Sex (odds ratio (OR): 0.40 (95% confidence interval (CI): 0.211-0.742), age (OR: 2.36 (95% CI: 1.02-5.44)), and underlying diseases (OR: 0.12 (95% CI: 0.06-0.23)) were independently associated factors for ADRs (P < 0.05). Conclusions: The frequency of ADRs and potential DDI was high compared to their use during nonpandemic times (e.g., for malaria, HIV, or inflammatory diseases). The safety profile of these drugs when used for COVID-19 treatment showed similar characteristics. Comorbidities, age >37 years old, and female sex were associated with ADRs.

Ancient DNA from an Early Neolithic Iberian population supports a pioneer colonization by first farmers.

The Neolithic transition has been widely debated particularly regarding the extent to which this revolution implied a demographic expansion from the Near East. We attempted to shed some light on this process in northeastern Iberia by combining ancient DNA (aDNA) data from Early Neolithic settlers and published DNA data from Middle Neolithic and modern samples from the same region. We successfully extracted and amplified mitochondrial DNA from 13 human specimens, found at three archaeological sites dated back to the Cardial culture in the Early Neolithic (Can Sadurní and Chaves) and to the Late Early Neolithic (Sant Pau del Camp). We found that haplogroups with a low frequency in modern populations-N* and X1-are found at higher frequencies in our Early Neolithic population (∼31%). Genetic differentiation between Early and Middle Neolithic populations was significant (F(ST) ∼0.13, P<10(-5)), suggesting that genetic drift played an important role at this time. To improve our understanding of the Neolithic demographic processes, we used a Bayesian coalescence-based simulation approach to identify the most likely of three demographic scenarios that might explain the genetic data. The three scenarios were chosen to reflect archaeological knowledge and previous genetic studies using similar inferential approaches. We found that models that ignore population structure, as previously used in aDNA studies, are unlikely to explain the data. Our results are compatible with a pioneer colonization of northeastern Iberia at the Early Neolithic characterized by the arrival of small genetically distinctive groups, showing cultural and genetic connections with the Near East.

ZnO nanowire co-growth on SiO2 and C by carbothermal reduction and vapour advection.

Vertically aligned ZnO nanowires (NWs) were grown on Au-nanocluster-seeded amorphous SiO(2) films by the advective transport and deposition of Zn vapours obtained from the carbothermal reaction of graphite and ZnO powders. Both the NW volume and visible-to-UV photoluminescence ratio were found to be strong functions of, and hence could be tailored by, the (ZnO+C) source-SiO(2) substrate distance. We observe C flakes on the ZnO NWs/SiO(2) substrates which exhibit short NWs that developed on both sides. The SiO(2) and C substrates/NW interfaces were studied in detail to determine growth mechanisms. NWs on Au-seeded SiO(2) were promoted by a rough ZnO seed layer whose formation was catalysed by the Au clusters. In contrast, NWs grew without any seed on C. A correlation comprising three orders of magnitude between the visible-to-UV photoluminescence intensity ratio and the NW volume is found, which results from a characteristic Zn partial pressure profile that fixes both O deficiency defect concentration and growth rate.

[Ethical issues in primary care during the coronavirus (SARS-CoV-2) pandemic]. / Problemas éticos en atención primaria durante la pandemia del coronavirus (SARS-CoV-2).

Public health emergencies, such as the current SARS-CoV-2 coronavirus pandemic, have led to tragic resource constraints that prevent lives from being saved. This has led to tensions in patient-centered care as the backbone of the system in normal conditions and the same care in emergencies originating in the COVID-19. In this review we address some of the healthcare, organizational and ethical problems that this scenario has caused in primary care such as: cancellation of programmed activities; scarce home care and follow-up of elderly, chronically ill and immobilized patients; shortage of PPE and the exposure to risk of healthcare professionals, and finally the problems associated with telemedicine and telephone attention to patients.

Electrical characteristics of core-shell p-n GaAs nanowire structures with Te as the n-dopant.

GaAs nanowire (NW)-based p-n photovoltaic devices, with two distinct p and n spatial distributions and where Te was the n-dopant, have been studied by impedance spectroscopy in the 10(3)-10(7) Hz frequency range and the - 1.5-1.5 V bias range. For a large n-core/p-shell overlap region within NWs in a coaxial geometry, the p-n junction properties (DC rectification and p-n depletion capacitance) are found to prevail. The impedance data at low bias for both NW devices show large frequency dispersions with relaxation frequencies that are compatible with carrier re-emission times from traps due to GaAs surface states. An increasing conductance with increasing frequency for low bias is observed, suggesting hopping transport through localized states. For large bias the conductance increases exponentially with bias and is frequency independent, indicating conduction through extended states in this regime.

[Thoracoscopic lobectomy in pediatrics. Our experience and new treatment perspectives]. / Lobectomía por toracoscopia en pediatría. Nuestra experiencia y nuevas perspectivas de tratamiento.

OBJECTIVES: Pulmonary malformations in the child are a wide clinical and pathologycal spectrum. The congenital cystic adenomatoid malformation and the pulmonary sequestration both produce many symptoms, from the asymptomatic to the most complicated, and its management remains controversial. Moreover, in the last years many new publications show that this surgery can be perfectly accomplished with the thoracoscopic approach as an alternative to the tradicional open surgery. In this paper we analyse our experience in performing lobectomies with thoracoscopy. This technique shows to be safe and has less complications than tradicional thoracotomy. METHODS: During the period 2004-2008 lobectomies were performed in six patiens, with ages between one week and fifteen years. The diagnostics where CAM in four cases, associated to PS in one case; broncogenic cyst in none case, and cavitary pulomonar aspergilloma in one case. RESULTS: Five inferior and one median lobectomies were done. In two cases the patients had no symptoms before intervention, the other four cases were asymptomatic. In all cases the toracoscopy was performed with 3 or 4 ports of 3-5 mm. No mini-thoracotomy was done in any case. There were nor intraoperatory neither postoperatory complications. In all patients were placed two thoracic drainages, being retired 3 to 4 days later. All patients, except one, remained five days in hospital. CONCLUSIONS: In this work, thoracoscopic lobectomy is confirmed as safe technique and with less complications and morbidity than the open lobectomy. Therefore, we suggest new posible aplications.

Hydroxyapatite extraction from fish scales of Tilapia.

Hydroxyapatite is the inorganic component of human bones. To be used for bone replacements, hydroxyapatite can be synthesized or extracted from natural components. In this work we present the hydroxyapatite extraction from fish scales of the same Orechromis family (Tilapia) but from two different species usually consumed in Mexico and in Spain. Our results indicate, for both species, that it is possible to obtain hydroxyapatite, and moreover, that this biomaterial is enriched with magnesium for the Mexican Oreochromis hunteri, and with aluminum for the Spanish Oreochromis niloticus.

[Evaluation of two immunochromatography kits for rapid diagnosis of rotavirus infections]. / Evaluación de dos equipos inmunocromatográficos comerciales para el diagnóstico rápido de la infección por rotavirus.

A prospective study was conducted to evaluate two immunochromatography (ICG) commercial kits for diagnosis of rotavirus infection, VIKIA Rota-Adeno (bioMérieux) and Simple Rota-Adeno (Operon). Reverse transcriptase and polymerase chain reaction (RT-PCR) with specific primers for the VP7 gene of group A rotavirus was used as the reference method. The sensitivity and specificity of the ICG tests compared with those of the reference method were 98.4% and 84.8%, respectively, for Simple Rota-Adeno (Operon), and 100% and 24.2% for VlKIA Rota-Adeno (bioMérieux). It is remarkable the low specificity of the latter method, which yields a high number of false positive results. The predictive value of a positive result by this method was only 71.6%. Most of the detected rotavirus strains corresponded to genotype G9P[8] (65%), followed by G1P[8] (25.4%) and G2P[8] (3.2%).

Proteína precursora del beta-amiloide (ß-App) y daño axonal difuso tras un traumatismo craneoencefálico: un punto de vista forense / Beta-amiloid precursos protein (ß-App) and diffuse axonal damage after head injuries: a forensic point of view

Resumen La proteína precursora del β- Amiloide (β-APP) es una glicoproteína de membrana y un componente habitual de las neuronas. Tiene funciones en el crecimiento y la adhesión celular tras un traumatismo. Es transportada mediante transporte rápido axonal anterógrado y se acumula dentro de las neuronas cuando se daña citoesqueleto. Este proceso es activo, es decir consume energía. El β-APP no es específico de los traumatismos. Se acumula en cualquier circunstancia en la que se dañen los axones, tal como la hipoxia, alteraciones metabólicas, y cualquier otra causa de edema cerebral y aumento de la presión intracraneal que puedan conducir a un daño axonal difuso (DAI) En el presente estudio estudiamos la expresión de esta proteína en casos de traumatismo cráneo-encefálico con diferente evolución cronológica El daño del citoesqueleto producido por la proteólisis, junto con la alteración de las quinasas y las fosfatasas, aumentan la permeabilidad de la membrana, lo que provoca la entrada de calcio en la célula que, a su vez, activa la calmodulina que hace que los neurofilamentos se compacten, los microtúbulos desaparezcan y se rompa la espectrina. Esta disrupción del citoesqueleto tiene como consecuencia que las sustancias que se transportan a su través, se acumulen, sobre todo en las zonas afectadas por el DAI. Al final de todo este proceso, los axones se rompen, lo que se conoce como axotomía secundaria. El estudio de la acumulación del β-APP es útil para valorar la extensión del DAI y para determinar el tiempo de supervivencia tras el traumatismo o cualquier otro daño cerebral.

Abstract β-Amyloid Precursor Protein (β-APP) is a membrane glycoprotein and a common component of neurons. It is involved in adhesion and cell growth processes after traumatic events. It is carried by anterograde fast axonal transport, and it accumulates inside neurons when the cytoskeleton is damaged. This is a vital biochemical process that consumes energy. β-APP is not specific of traumatic events. It accumulates in any case of axonal damage, whatever its cause may be, like hypoxia, metabolic disorders, and any other circumstances that lead to brain swelling and intracranial pressure rising and in consequence to Diffuse Axonal Injury (DAI). In this study we review the expression of this protein in cases of traumatic brain injury with different chronological evolution. The damage of cytoskeleton due to proteolysis in addition to the disturbance of kinases and phosphatases increase the permeability of the membrane. Calcium gets into the cell and activates calmodulin, thus neurofilaments compact, microtubules disappear and spectrin breaks. This disruption of the cytoskeleton has as consequence that the transported substances accumulate in the most affected areas by DAI. At the end of this process axon breaks, which is known as secondary axotomy. The study of the accumulation of β-APP is useful to assess the extent of DAI and to determine the time elapsed after trauma or another insult to CNS.