Experiments in atomic physics, spectroscopy, and metrology require the compulsory use of frequency- and/or power-stabilized laser beams. For this purpose, acousto-optic modulators (AOMs) or electro-optic modulators are commonly used. AOMs are the most widely employed because of their ability to not only control the frequency and amplitude but also manipulate the spatial deflection of the beam. The operation of AOMs requires stable radio frequency oscillators, which can be implemented using Direct Digital Synthesis (DDS) systems or Voltage-Controlled Oscillators (VCOs). DDS systems offer high precision and a wide range of operating frequencies but at a high cost and with a more complex experimental setup. However, VCO-based systems provide excellent resolution, are more cost-effective, and can be implemented more rapidly in the final application because of their low complexity. In this work, a detailed design of a compact system for controlling an AOM, which is easily constructed based on a VCO and some readily available discrete components, is presented. The constructed device was successfully used in two applications for controlling an extended cavity diode laser: one to reduce typical undesired fluctuations in laser intensity and the other for laser frequency stabilization to a hyperfine structure transition of the rubidium D2 line.

Laser diodes (LDs) working in free mode present different types of effects such as shift and broadening of the spectral peak, determined by external factors such as temperature, electric current or mechanical vibrations, which are undesirable when required in applications such as high resolution laser spectroscopy, metrology or laser cooling. To reduce the width of the spectral emission peak of a laser, different configurations or optical setups are used, among which one of the most effective is to extend the optical resonator of the LD and use optical feedback, either with the help of a partially reflective mirror or with a diffraction grating. In this work, we present the design, construction, and characterization of a compact extended-cavity diode laser (ECDL) in Littrow configuration. The ECDL was machined on an aluminum block using computerized numerical control. It operates at a wavelength of 780.24 nm with a maximum output power of 35 mW. The results showed a spectral linewidth of 340 kHz using the self-heterodyne technique and a frequency stability of 0.47 MHz when the cavity was stabilized with an atomic reference.

In this work, we report estimates of the temperature and electron density of titanium plasmas using time-resolved laser-induced breakdown spectroscopy (LIBS) methods and results of Hartree–Fock relativistic (HFR) calculations of Ti II transition probabilities. Plasmas were generated on certified grade-1 titanium samples, with 532-nm laser radiation pulses from a Nd:YAG laser with energies of 18, 28, 38, and 48 mJ. Spectra were recorded with delay times between 0.5 and $6.5~\mu \text{s}$ with 0.5- $\mu \text{s}$ intervals. The calculation of Ti II transition probabilities included reported configurations of the Rydberg series as well as six new unreported configurations of each parity. For the estimation of the electronic temperature using the Boltzmann plot, 13 Ti II lines and eight Ti I lines measured in the LIBS spectra of the plasmas were used, obtaining values between 7700K and 11700 K with an uncertainty around 15%. On the other hand, the estimated plasma electron density range was (9–18) $\times 10^{16}$ cm-3, with an uncertainty of about 20% using a Lorentzian fit of the Stark broadening of measured Ti II lines. A comparison of the obtained electron density with that calculated from the Saha–Boltzmann equation is also presented.

Different studies show that training load is an important cause in the involvement of sports injuries and have identified variables such as the volume and intensity of training that are key to injury prevention. The objective of this study is to reduce the incidence of injuries by implementing six preventive measures. The study included 12 players of the first team of "Sala 10 Zaragoza" of the First Division of the Futsal League of Spain. This is a longitudinal comparative study of the incidence of injuries in the 2016-2017 season and the 2004-2005 season. The results obtained reveal a total of 28 and 108 registered injuries and a lesion incidence of 6.86 and 19.72 during the 2016-2017 season and the 2004-2005 season, respectively. The number of match minutes lost was much lower in the 2016-2017 season, compared to the 2004-2005 season, 6,660 versus 31,500 minutes.

Diferentes estudios evidencian que la carga de entrenamiento es una causa importante en la afectación de lesiones deportivas y han identificado variables como el volumen y la intensidad del entrenamiento claves para la prevención de lesiones. El objetivo de este estudio es reducir la incidencia de lesiones implementando seis medidas preventivas. El estudio incluyó 12 jugadores del primer equipo de "Sala 10 Zaragoza" de la Primera División de la Liga de Futsal de España. Se trata de un estudio longitudinal comparativo de la incidencia de lesiones en la temporada 2016-2017 y la temporada 2004-2005. Los resultados obtenidos revelan un total de 28 y 108 lesiones registradas y una incidencia lesional de 6,86 y 19,72 durante la temporada 2016-2017 y la temporada 2004-2005, respectivamente. El número de minutos de partido perdidos fue mucho más bajo en la temporada 2016-2017, en comparación con la temporada 2004-2005, 6.660 frente a 31.500 minutos.

In this work, the application of Laser Induced Plasma Spectroscopy (LIBS) is presented as a complementary method for the study and characterization of an underground water sample from the "El Limon" trail in the municipality of Palmar de Varela - Atlantico in Colombia. To carry out the study, the Geophysical electrical prospecting technique was first used, in order to identify underground aquifers in the study area, later the water samples were extracted and then analyzed using the LIBS technique. For the generation of the plasma-laser, a pulsed Nd: Yag laser was used with a length of 532 nm and a duration of similar to 5ns, the laser radiation on the sample was focused using a converging lens of 12 cm focal length, the energy per pulse was approximately 60 mJ, the relative humidity of the environment was 55% with a temperature of 24 degrees C. The spectra of the laser plasma on the sample were recorded with an Echelle type spectrograph coupled to an ICCD camera within the spectral region of 200-950 nm. The spectral assignment of the lines found in the spectra of the sample was carried out, compared with the spectra taken from spectral sources known as: plasma-laser in Air and the NIST database, identifying the elements present Ca, N, Cl, O, F, and Na.

The use of soft and flexible materials in rehabilitation support systems based on robotic exoskeletons plays a crucial role in ergonomics, reducing weight and complexity. However, the selection of these materials can have mechanical implications that affect the performance of the exoskeleton in the chosen application. This paper proposes a testing protocol to assess the mechanical and structural features of a prototype upper limb robotic exoskeleton using an optical motion capture system as the primary measurement instrument. In addition to the protocol, a literature review is presented, laying the ground for the theoretical development of the mechanical evaluation for prototypes. Also, the materials used concerning the evaluation technologies required for data collection and assessment of the devices are described. The development and future application of this protocol will enable the identification of the relevant motion parameters on the exoskeleton prototype, the changes that its structure may experience due to the use of the flexible materials, and the effectiveness of the mechanical support provided in the upper limb. Finally, the proposed protocol can be extended to other types of robotic exoskeletons built with similar materials, regardless of their final application, extending its applicability to other study cases.

Rationale: Sarcopenia and malnutrition cause functional impairment in sick individuals. Its prevention and treatment showed positive effects. Our aim were to define the nutritional and functional status of patients with SARS CoV-2 infection upon admission to the ICU and during their evolution Methods: Observational, retrospective study, in conditions of usual clinical practice, of patients with critical SARS-CoV2 infection, admitted to the ICU between 09/03-30/09, 2020, and their evolution 3 and 6 months after discharge. Were analyzed demographics outcomes, clinical history, nutritional screening (MUST) and sarcopenia (SARC-f), Barthel index, nutritional therapy (NT), invasive mechanical ventilation (IMV), stays in ICU, hospital and mortality. Results: 150 patients (94V, 56M), mean age 60 years (28-87). Obesity (56.7%) and overweight (31.3%). 46% have a MUST ≥2; 48% met GLIM criteria for malnutrition. This malnourished patients had a 15-day stay more in the ICU (25.78± 2.84 vs 9.9±10.054; p<0.027) and 26.5 more in hospitalization (49, 9±34.7 vs 23.3±13.4; p<0.015). Patients with weight loss ≥5% had 11.21 more days of IMV (p <0.004). 47.3% presented SARC-f ≥4 with prolonged stays in ICU (24.4±22.04 vs 13.2 ±10.3 days; p<0.016), and hospital (48.5±33.7 vs 25,7±13.2 days; p <0.005). Only 4% of the patients were independent at discharge from the ICU. At 6 months, 17 patients maintained some degree of dependence. Mortality was 33%. All patients received NT according to protocol, enteral nutrition exclusively (88%) or exclusive or complementary parenteral nutrition (29.3%) during their stay in the ICU. Statistical analysis was performed using SPSS 26.0. Conclusion: Critical COVID patients have a high prevalence of obesity, malnutrition, sarcopenia and dependence. Malnutrition and sarcopenia affects more days of IMV and prolonged ICU and hospital stays. Screening for both entities is key upon admission to hospital. References: 1. Thibault R, Seguin P, Tamion F, Pichard C, Singer P. Nutrition of the COVID-19 patient in the intensive care unit (ICU): a practical guidance. Crit Care. 2020 Jul 19;24(1):447. Disclosure of Interest: None declared.

We described the characterization of an acousto-optic modulation system and the optimization of the set up to improve the efficiency of diffraction in single and double-pass configurations. In the single-pass configuration, the system consists of an acousto-optic modulator, a voltage-controlled oscillator (VCO) and a radio frequency amplifier, in which the diffraction efficiency and the optical power of the diffracted beam were characterized in the function of the applied radiofrequency. Additionally, taking as a reference the need to correct the variation of the diffraction angle that may occur when the system is modulated in frequency in a simple step, its correction is presented by means of the implementation of the configuration in double step. The double-pass configuration consists of a VCO that controls the incoming acoustic signal to the modulator, a modulator which diffracts the incident light and this passes through a retarder sheet to avoid the retroreflection of the beam; Then, using an iris, only order 1 of diffraction of the beam was allowed to pass and a plane mirror was used for working in the infrared which directs the laser in the second pass of it in the modulator. Once the double-pass system had been optimized, the diffraction efficiency curve was obtained. This work is presented as an updated guide for the implementation of an acousto-optic modulation system in a double-pass configuration.

INTRODUCTION:Zenker's diverticulum is an uncommon pathology of the upper oesophageal sphincter whose most frequent symptoms are the association of dysphagia and regurgitation. It is more frequent in advanced ages, and its treatment of choice is surgery in symptomatic cases.METHOD:A retrospective descriptive study was performed of 27 patients operated in the Otorhinolaryngology service of the Hospital Universitario de Cabueñes between 2007 and 2019 using laser endoscopic surgery.RESULTS:27 patients were operated, 70.4% male and 29.6% female, with a mean age of 67 years (range between 30 and 91). The most frequent symptom at diagnosis was dysphagia. No intraoperative complications were observed. One patient (3.7%) presented post-surgical fever, and another patient (3.7%) had a serious complication due to oesophageal perforation secondary to postsurgical emesis. The median hospital stay was 5 days, and the median oral intake was 4 days. Recurrence was observed in 6 patients (22.2%), 4 (14.8%) requiring a second intervention, which was performed using the same technique.DISCUSSION AND CONCLUSIONS:The surgical treatment of Zenker's diverticulum has advanced in recent decades, with endoscopic treatment currently being the choice. Among the surgical options, endoscopic CO2 laser surgery is an effective and safe alternative, although possible complications must be considered. It is also an effective alternative for the treatment of recurrences.

Rationale: Tube feeding (TF) is the most widely used route of enteral nutrition (EN). Accidental and self –withdrawal, especially in agitated patients or patients with endotracheal intubation, is a frequent complication to avoid. The nasal bridle (NB) is an alternative method to containment measures. Our aim was to review the efficacy and safety of BN in a population of patients requiring EN by tube.

This paper provides use case definitions and a high-level system architecture overview for human robot interaction in a fog computing-based Human in The Loop Cyber Physical System. Our focus is to develop a practical, natural, meaningful human robot interaction framework for single and multiple avatar (CPS) robots, and this paper outlines the research road ahead of us.

In this work was used laser induced breakdown spectroscopy to study and characterize a sample of austenitic, steel American Iron and Steel Institute nomenclature, 304 series, with the objective of identifying constituent elements in the material. The steel was chosen because it is an economic and multipurpose material, which due to its physical characteristics, it is of great interest in the construction industry, design of tools and mechanical equipment. The contributions of this research to the industrial and metallurgical sector is that the laser induced breakdown spectroscopy technique allows to reduce costs in the experimental execution for qualitative studies of steels. Plasma generation was performed by focusing the radiation laser on the surface of a sample of steel. Plasma radiation generated was conducted through an optical fiber to a Mechelle spectrograph attached to an Intensified charge coupled device camera. The information obtained through the spectra allowed the characterization of the plasma by means of the parameters electronic temperature and electronic density, as well as the elementary identification of constituents of the steel sample, allowing identify major elements such as chromium, nickel, manganese and silicon, being concordant with the composition of elements present in the austenitic steel.

The COVID-19 pandemic has posed a significant challenge to public health systems worldwide. Obesity and malnutrition, two silent pandemics that were present before the emergence of SARS-CoV-2 infection, condition risk of the disease worsening in infected patients. Patients with this illness present with a high risk of disease-related malnutrition (DRM) and sarcopenia due to symptoms arising from the infection itself, acute inflammation, prolonged bed rest, and the supportive therapies used. Nowadays, along with respiratory support, nutritional support is essential to healthcare for patients with coronavirus infection throughout their progress. The nutritional approach is a dynamic process that includes strengthening the normal diet and specialized nutritional treatment (SNT) with the use of oral supplements, enteral nutrition, or parenteral nutrition according to each patient's requirements and needs. In this update, we review aspects regarding the close relationship between diet, nutrition, and immunity; their impact on the progress of SARS-CoV-2 infection; and the therapeutic strategies proposed by the consensus of experts of scientific societies.

The acousto-optic modulator is a popular tool in photonic laboratories for amplitude modulation or frequency tuning. Due to the unique feature of the modified frequency diffraction, the acousto-optic modulator can also serve as a key element in laser spectroscopy. In this work, the characterization of an acousto-optic system is presented. For the characterization of the beam, diffracted by this system, the modulators efficiency was optimized based on its vertical positioning, and also the beams angle and position. The profiles of the diffracted beams under the frequency modulation are shown up, down, and near of the modulation’s central frequencyIn an AOM, the light is scattered from successive wavefronts that interoperate constructively. The condition for the constructive interference of scattered light is given by the Equation (1), in which the favoring of the orders diffracted by the modulator can be seen as predicted by the acousto-optic principle.

Abstract The spectral and electrical diagnostics of plasmas generated by laser were performed by using the LIBS technique accompanied with simultaneous measurements of the electrical signal in the perturbations of an aluminum plasma laser, submerged in electric fields transverse to the direction of the beam laser produced by a parallel flat plates capacitor. In this paper, we show that temperature and electron density in the formed plasmas are directly proportional to the energy deposited by the beam laser on the sample. Depending on the separation of the plates, the analysis of the electrical signal shows that it decays approximately with the inverse of the squared distance and it also decays with the number of laser pulses for plasmas produced on the same region of the solid sample.

This document describes thoroughly the construction of two spectroscopic systems: One system for obtaining fluorescence spectra and another system for obtaining the fluorescence lifetime. The first system consists of obtaining the fluorescence spectrum and is constituted by a Czerny-Turner type monochromator, a photomultiplier tube (PMT), a system for modulating the excitation signal and a system for treating and filtering the fluorescent signal constituted by an electromechanical chopper, a lock-in amplifier and a fast response PMT; plus a set of lenses and a samples holder. The fluorescein dissolved in ethanol was used as a calibration standard, and an Nd:YAG laser source was used as a source of excitation, which emits in 532 nm, of continuous wave and stable power in time adjustable by current. On the other hand, a fluorescence time-resolved system was developed. This system consists of obtaining the fluorescence lifetime of different samples under study from a Voltage curve Vs Time obtained from the system and showing the decay behavior of the phenomenon. This has a pulsed laser unit as a source of excitation, emitting at 532 nm, 80 mJ of energy and with a pulse width of 4 ns. For this system, two semiconductor photodiode detectors with fast response have been built; both with a response of temporary uptake above 1 ns, thus providing obtaining fluorescence lifetime up to this value. Fluorescein was also used in this system as a standard sample, but in this case dissolved in a buffer-like solution; accompanied also by a brief study of the change in the average lifespan of fluorescence in function of the pH of the solution. The results obtained show that two automated systems, reproducible, accurate and of very low cost compared to the current ones, have been successfully implemented for the study of steady-state and time-resolved fluorescence spectroscopy.

Seasonal influenza is a cause of hospitalization, especially in people with underlying disease or extreme age, and its severity may differ depending on the types and subtypes of circulating viruses. We investigated the factors associated with ICU admission or death in hospitalized patients with severe laboratory-confirmed influenza according to the viral type and subtype. An observational epidemiological study was carried out in patients aged ≥18 years from 12 Catalan hospitals between 2010 and 2016. For each reported case we collected demographic, virological and clinical characteristics. A mixed-effects logistic regression model was used to estimate crude and adjusted ORs. 1726 hospitalized patients were included: 595 (34.5%) were admitted to the ICU and 224 (13.0%) died. Lower ICU admission was associated with age ≥75 years in all influenza types and subtypes and with age 65-74 years for type A. In contrast, the 65-74 and ≥75 years age groups were associated with an increased risk of death in all types and subtypes, especially for type B (aOR 27.42, 95% CI: 4.95-151.93 and 15.96; 95% CI: 3.01-84.68). The comorbidity most closely associated with severe outcomes was immune deficiency, which was associated with death for type B (aOR 9.02, 95% CI: 3.05-26.69) and subtype A(H1N1)pdm09 (aOR 3.16, 95% CI: 1.77-5.66). Older age was a differential factor for ICU admission and death: it was associated with lower ICU admission but a risk factor for death. The comorbidity with the closest association with death was immune deficiency, mainly in influenza type B patients.

In this paper, we present the main results for the theoretical, numerical and experimental analysis of a new method to measure the roughness of metal surfaces. The requirements for a waveguide optical resonator, which is the main optical node of the device implementing this method, have been developed. A comparative analysis of two different designs of an optical node is performed. The energy spectra of the roughness of various surfaces were measured. As a result of the research, the main advantages of the method under consideration and practical recommendations are provided to improve the design of the device that implements this method.