RESUMEN
When dealing with drowning scenarios, time is of capital importance. In this sense, the search for innovative strategies that provide more effectiveness and safety for lifesaving professionals, as well as for bathers, is essential. The aim of this study was to systematically review the feasibility and effectiveness of unmanned aerial vehicles as a tool to assist lifeguards in performing their duties. A systematic literature search was conducted in October 2023 across the databases PubMed, Web of Science, Academic Search Complete, and Scopus, using the search terms: ((drone) OR (Unmanned Aerial Vehicles)) AND ((drowning) OR (water rescue)). A total of 5 studies were included in this review, whose quality ranged from moderate to strong, according to the EPHPP Quality Assessment Tool for Quantitative Studies. The results suggest that unmanned aerial vehicles may assist lifeguards in the prevention, detection, and rescue of drowning victims and people in distress in the water. Although preliminary, evidence suggests that lifeguards would benefit from the use of unmanned aerial vehicles regarding lifeguards' and others' safety.
RESUMEN
Gelation of protein condensates formed by liquid-liquid phase separation occurs in a wide range of biological contexts, from the assembly of biomaterials to the formation of fibrillar aggregates, and is therefore of interest for biomedical applications. Soluble-to-gel (sol-gel) transitions are controlled through macroscopic processes such as changes in temperature or buffer composition, resulting in bulk conversion of liquid droplets into microgels within minutes to hours. Using microscopy and mass spectrometry, we show that condensates of an engineered mini-spidroin (NT2repCTYF) undergo a spontaneous sol-gel transition resulting in the loss of exchange of proteins between the soluble and the condensed phase. This feature enables us to specifically trap a silk-domain-tagged target protein in the spidroin microgels. Surprisingly, laser pulses trigger near-instant gelation. By loading the condensates with fluorescent dyes or drugs, we can control the wavelength at which gelation is triggered. Fluorescence microscopy reveals that laser-induced gelation significantly further increases the partitioning of the fluorescent molecules into the condensates. In summary, our findings demonstrate direct control of phase transitions in individual condensates, opening new avenues for functional and structural characterization.
Asunto(s)
Rayos Láser , Transición de Fase , Fibroínas/química , Colorantes Fluorescentes/química , Geles/químicaRESUMEN
Detecting microsecond structural perturbations in biomolecules has wide relevance in biology, chemistry and medicine. Here we show how MHz repetition rates at X-ray free-electron lasers can be used to produce microsecond time-series of protein scattering with exceptionally low noise levels of 0.001%. We demonstrate the approach by examining JÉ helix unfolding of a light-oxygen-voltage photosensory domain. This time-resolved acquisition strategy is easy to implement and widely applicable for direct observation of structural dynamics of many biochemical processes.
RESUMEN
PURPOSE: There are multiple postexercise recovery technologies available in the market based on the assumption of blood-flow enhancement. Lower-limb intermittent pneumatic compression (IPC) has been widely used, but the available scientific evidence supporting its effectiveness remains scarce, requiring a deeper investigation into its underlying mechanisms. The aim of this study was to assess the hemodynamic effects caused by the use of IPC at rest. METHODS: Twenty-two soccer and track and field athletes underwent two 15-minute IPC protocols (moderate- [80 mm Hg] and high-pressure [200 mm Hg]) in a randomized order. Systolic peak velocity, end-diastolic peak velocity, arterial diameter, and heart rate were measured before, during (at the eighth minute), and 2 minutes after each IPC protocol. RESULTS: Significant effects were observed between before and during (eighth minute) the IPC protocol for measures of systolic (P < .001) and end-diastolic peak velocities (P < .001), with the greater effects observed during the high-pressure protocol. Moreover, 2 minutes after each IPC protocol, hemodynamic variables returned to values close to baseline. Arterial diameter presented significant differences between pressures during the IPC protocols (P < .05), while heart rate remained unaltered. CONCLUSION: IPC effectively enhances transitory blood flow of athletes, particularly when applying high-pressure protocols.
Asunto(s)
Estudios Cruzados , Frecuencia Cardíaca , Hemodinámica , Aparatos de Compresión Neumática Intermitente , Fútbol , Humanos , Fútbol/fisiología , Frecuencia Cardíaca/fisiología , Masculino , Hemodinámica/fisiología , Adulto Joven , Método Doble Ciego , Atletismo/fisiología , Adulto , Velocidad del Flujo Sanguíneo/fisiología , Atletas , Flujo Sanguíneo Regional , Extremidad Inferior/irrigación sanguínea , Extremidad Inferior/fisiologíaRESUMEN
Nanoparticles, exhibiting functionally relevant structural heterogeneity, are at the forefront of cutting-edge research. Now, high-throughput single-particle imaging (SPI) with X-ray free-electron lasers (XFELs) creates opportunities for recovering the shape distributions of millions of particles that exhibit functionally relevant structural heterogeneity. To realize this potential, three challenges have to be overcome: (1) simultaneous parametrization of structural variability in real and reciprocal spaces; (2) efficiently inferring the latent parameters of each SPI measurement; (3) scaling up comparisons between 105 structural models and 106 XFEL-SPI measurements. Here, we describe how we overcame these three challenges to resolve the nonequilibrium shape distributions within millions of gold nanoparticles imaged at the European XFEL. These shape distributions allowed us to quantify the degree of asymmetry in these particles, discover a relatively stable "shape envelope" among nanoparticles, discern finite-size effects related to shape-controlling surfactants, and extrapolate nanoparticles' shapes to their idealized thermodynamic limit. Ultimately, these demonstrations show that XFEL SPI can help transform nanoparticle shape characterization from anecdotally interesting to statistically meaningful.
RESUMEN
Research has highlighted the need for training lifeguards in psychosocial skills. Therefore, this study aims to analyze the effectiveness of a short 10-h training program encompassing dimensions associated with emotional management, focus of attention, interpersonal relationships, and lifeguard behavior, and its effects on their psychosocial skills. A total of 64 lifeguards with experience ranging from 1 to 25 years (M = 5.93, SD = 6.07), randomly divided into experimental and control groups, participated in this study. The d2 Test of Attention, the Social Intelligence Test of O'Sullivan and Guilford, and the MSCEIT Emotional Intelligence Test were used to assess psychosocial skills. A multivariate analysis of variance for repeated measures (2 × 3 (Group × Time) MANOVA) was performed to analyze the effects of the training program on psychosocial skills. The results revealed that the experimental group showed statistically significant improvements in focus of attention and emotional intelligence compared to the control group. However, it is worth noting that no statistically significant group interactions were observed for measures of social intelligence. Taken together, these results seem to highlight the importance of including psychosocial content in the general training of lifeguards.
Asunto(s)
Inteligencia Emocional , Humanos , Proyectos Piloto , Masculino , Adulto , Femenino , Persona de Mediana Edad , Adulto Joven , Habilidades SocialesRESUMEN
Imaging the structure and observing the dynamics of isolated proteins using single-particle X-ray diffractive imaging (SPI) is one of the potential applications of X-ray free-electron lasers (XFELs). Currently, SPI experiments on isolated proteins are limited by three factors: low signal strength, limited data and high background from gas scattering. The last two factors are largely due to the shortcomings of the aerosol sample delivery methods in use. Here we present our modified electrospray ionization (ESI) source, which we dubbed helium-ESI (He-ESI). With it, we increased particle delivery into the interaction region by a factor of 10, for 26 nm-sized biological particles, and decreased the gas load in the interaction chamber corresponding to an 80% reduction in gas scattering when compared to the original ESI. These improvements have the potential to significantly increase the quality and quantity of SPI diffraction patterns in future experiments using He-ESI, resulting in higher-resolution structures.
Asunto(s)
Helio , Proteínas , Rayos X , Difracción de Rayos X , Rayos LáserRESUMEN
This work investigates the performance of the electrospray aerosol generator at the European X-ray Free Electron Laser (EuXFEL). This generator is, together with an aerodynamic lens stack that transports the particles into the X-ray interaction vacuum chamber, the method of choice to deliver particles for single-particle coherent diffractive imaging (SPI) experiments at the EuXFEL. For these experiments to be successful, it is necessary to achieve high transmission of particles from solution into the vacuum interaction region. Particle transmission is highly dependent on efficient neutralization of the charged aerosol generated by the electrospray mechanism as well as the geometry in the vicinity of the Taylor cone. We report absolute particle transmission values for different neutralizers and geometries while keeping the conditions suitable for SPI experiments. Our findings reveal that a vacuum ultraviolet ionizer demonstrates a transmission efficiency approximately seven times greater than the soft X-ray ionizer used previously. Combined with an optimized orifice size on the counter electrode, we achieve >40% particle transmission from solution into the X-ray interaction region. These findings offer valuable insights for optimizing electrospray aerosol generator configurations and data rates for SPI experiments.
RESUMEN
The idea of using ultrashort X-ray pulses to obtain images of single proteins frozen in time has fascinated and inspired many. It was one of the arguments for building X-ray free-electron lasers. According to theory, the extremely intense pulses provide sufficient signal to dispense with using crystals as an amplifier, and the ultrashort pulse duration permits capturing the diffraction data before the sample inevitably explodes. This was first demonstrated on biological samples a decade ago on the giant mimivirus. Since then, a large collaboration has been pushing the limit of the smallest sample that can be imaged. The ability to capture snapshots on the timescale of atomic vibrations, while keeping the sample at room temperature, may allow probing the entire conformational phase space of macromolecules. Here we show the first observation of an X-ray diffraction pattern from a single protein, that of Escherichia coli GroEL which at 14 nm in diameter is the smallest biological sample ever imaged by X-rays, and demonstrate that the concept of diffraction before destruction extends to single proteins. From the pattern, it is possible to determine the approximate orientation of the protein. Our experiment demonstrates the feasibility of ultrafast imaging of single proteins, opening the way to single-molecule time-resolved studies on the femtosecond timescale.
RESUMEN
X-ray free-electron lasers (XFELs) can probe chemical and biological reactions as they unfold with unprecedented spatial and temporal resolution. A principal challenge in this pursuit involves the delivery of samples to the X-ray interaction point in such a way that produces data of the highest possible quality and with maximal efficiency. This is hampered by intrinsic constraints posed by the light source and operation within a beamline environment. For liquid samples, the solution typically involves some form of high-speed liquid jet, capable of keeping up with the rate of X-ray pulses. However, conventional jets are not ideal because of radiation-induced explosions of the jet, as well as their cylindrical geometry combined with the X-ray pointing instability of many beamlines which causes the interaction volume to differ for every pulse. This complicates data analysis and contributes to measurement errors. An alternative geometry is a liquid sheet jet which, with its constant thickness over large areas, eliminates the problems related to X-ray pointing. Since liquid sheets can be made very thin, the radiation-induced explosion is reduced, boosting their stability. These are especially attractive for experiments which benefit from small interaction volumes such as fluctuation X-ray scattering and several types of spectroscopy. Although their use has increased for soft X-ray applications in recent years, there has not yet been wide-scale adoption at XFELs. Here, gas-accelerated liquid sheet jet sample injection is demonstrated at the European XFEL SPB/SFX nano focus beamline. Its performance relative to a conventional liquid jet is evaluated and superior performance across several key factors has been found. This includes a thickness profile ranging from hundreds of nanometres to 60â nm, a fourfold increase in background stability and favorable radiation-induced explosion dynamics at high repetition rates up to 1.13â MHz. Its minute thickness also suggests that ultrafast single-particle solution scattering is a possibility.
RESUMEN
Viral diseases are the cause of many global epidemics, leading to deaths, affecting the quality of life of populations, and impairing public health. The limitations in the treatment of viral diseases and the constant resistance to conventional antiviral treatments encourage researchers to discover new compounds. In this perspective, this literature review presents isolated molecules and extracts of natural products capable of inhibiting the activity of the nonstructural protein that acts as the RNA-dependent RNA polymerase. The literature review presented natural compounds with the potential to be tested as alternative medicines or used in the development of synthetic drugs to prevent the replication of RNA viruses, such as COVID-19, hepatitis C, and dengue viruses, among others. Natural products are known to exhibit remarkable activities in mitigation of different viral diseases, in addition, they help to decrease the aggravation of infections. Consequently, reducing hospitalization time and deaths.
RESUMEN
One of the outstanding analytical problems in X-ray single-particle imaging (SPI) is the classification of structural heterogeneity, which is especially difficult given the low signal-to-noise ratios of individual patterns and the fact that even identical objects can yield patterns that vary greatly when orientation is taken into consideration. Proposed here are two methods which explicitly account for this orientation-induced variation and can robustly determine the structural landscape of a sample ensemble. The first, termed common-line principal component analysis (PCA), provides a rough classification which is essentially parameter free and can be run automatically on any SPI dataset. The second method, utilizing variation auto-encoders (VAEs), can generate 3D structures of the objects at any point in the structural landscape. Both these methods are implemented in combination with the noise-tolerant expand-maximize-compress (EMC) algorithm and its utility is demonstrated by applying it to an experimental dataset from gold nanoparticles with only a few thousand photons per pattern. Both discrete structural classes and continuous deformations are recovered. These developments diverge from previous approaches of extracting reproducible subsets of patterns from a dataset and open up the possibility of moving beyond the study of homogeneous sample sets to addressing open questions on topics such as nanocrystal growth and dynamics, as well as phase transitions which have not been externally triggered.
RESUMEN
Free-electron lasers could enable X-ray imaging of single biological macromolecules and the study of protein dynamics, paving the way for a powerful new imaging tool in structural biology, but a low signal-to-noise ratio and missing regions in the detectors, colloquially termed 'masks', affect data collection and hamper real-time evaluation of experimental data. In this article, the challenges posed by noise and masks are tackled by introducing a neural network pipeline that aims to restore diffraction intensities. For training and testing of the model, a data set of diffraction patterns was simulated from 10â 900 different proteins with molecular weights within the range of 10-100â kDa and collected at a photon energy of 8â keV. The method is compared with a simple low-pass filtering algorithm based on autocorrelation constraints. The results show an improvement in the mean-squared error of roughly two orders of magnitude in the presence of masks compared with the noisy data. The algorithm was also tested at increasing mask width, leading to the conclusion that demasking can achieve good results when the mask is smaller than half of the central speckle of the pattern. The results highlight the competitiveness of this model for data processing and the feasibility of restoring diffraction intensities from unknown structures in real time using deep learning methods. Finally, an example is shown of this preprocessing making orientation recovery more reliable, especially for data sets containing very few patterns, using the expansion-maximization-compression algorithm.
RESUMEN
Single Particle Imaging (SPI) with intense coherent X-ray pulses from X-ray free-electron lasers (XFELs) has the potential to produce molecular structures without the need for crystallization or freezing. Here we present a dataset of 285,944 diffraction patterns from aerosolized Coliphage PR772 virus particles injected into the femtosecond X-ray pulses of the Linac Coherent Light Source (LCLS). Additional exposures with background information are also deposited. The diffraction data were collected at the Atomic, Molecular and Optical Science Instrument (AMO) of the LCLS in 4 experimental beam times during a period of four years. The photon energy was either 1.2 or 1.7 keV and the pulse energy was between 2 and 4 mJ in a focal spot of about 1.3 µm x 1.7 µm full width at half maximum (FWHM). The X-ray laser pulses captured the particles in random orientations. The data offer insight into aerosolised virus particles in the gas phase, contain information relevant to improving experimental parameters, and provide a basis for developing algorithms for image analysis and reconstruction.
Asunto(s)
Colifagos , Rayos Láser , Aceleradores de Partículas , Virión , Difracción de Rayos XRESUMEN
X-ray free electron lasers (XFELs) now routinely produce millijoule level pulses of x-ray photons with tens of femtoseconds duration. Such x-ray intensities gave rise to the idea that weakly scattering particles-perhaps single biomolecules or viruses-could be investigated free of radiation damage. Here, we examine elements from the past decade of so-called single particle imaging with hard XFELs. We look at the progress made to date and identify some future possible directions for the field. In particular, we summarize the presently achieved resolutions as well as identifying the bottlenecks and enabling technologies to future resolution improvement, which in turn enables application to samples of scientific interest.
RESUMEN
The pressing need for knowledge of the detailed wavefront properties of ultra-bright and ultra-short pulses produced by free-electron lasers has spurred the development of several complementary characterization approaches. Here a method based on ptychography is presented that can retrieve high-resolution complex-valued wavefunctions of individual pulses without strong constraints on the illumination or sample object used. The technique is demonstrated within experimental conditions suited for diffraction experiments and exploiting Kirkpatrick-Baez focusing optics. This lensless technique, applicable to many other short-pulse instruments, can achieve diffraction-limited resolution.
RESUMEN
Non-enveloped icosahedral double-stranded RNA (dsRNA) viruses possess multifunctional capsids required for their proliferation. Whereas protozoan/fungal dsRNA viruses have a relatively simple capsid structure, which suffices for the intracellular phase in their life cycle, metazoan dsRNA viruses have acquired additional structural features as an adaptation for extracellular cell-to-cell transmission in multicellular hosts. Here, we present the first atomic model of a metazoan dsRNA totivirus-like virus and the structure reveals three unique structural traits: a C-terminal interlocking arm, surface projecting loops, and an obstruction at the pore on the 5-fold symmetry axis. These traits are keys to understanding the capsid functions of metazoan dsRNA viruses, such as particle stability and formation, cell entry, and endogenous intraparticle transcription of mRNA. On the basis of molecular dynamics simulations of the obstructed pore, we propose a possible mechanism of intraparticle transcription in totivirus-like viruses, which dynamically switches between open and closed states of the pore(s).
Asunto(s)
Cápside/química , ARN Bicatenario/química , ARN Viral/química , Totivirus/química , Cápside/metabolismo , Microscopía por Crioelectrón , Simulación de Dinámica Molecular , ARN Bicatenario/genética , ARN Viral/genética , Totivirus/fisiología , Internalización del Virus , Replicación ViralRESUMEN
Intense x-ray free-electron laser (XFEL) pulses hold great promise for imaging function in nanoscale and biological systems with atomic resolution. So far, however, the spatial resolution obtained from single shot experiments lags averaging static experiments. Here we report on a combined computational and experimental study about ultrafast diffractive imaging of sucrose clusters which are benchmark organic samples. Our theoretical model matches the experimental data from the water window to the keV x-ray regime. The large-scale dynamic scattering calculations reveal that transient phenomena driven by non-linear x-ray interaction are decisive for ultrafast imaging applications. Our study illuminates the complex interplay of the imaging process with the rapidly changing transient electronic structures in XFEL experiments and shows how computational models allow optimization of the parameters for ultrafast imaging experiments.
RESUMEN
Bragg coherent diffraction imaging is a powerful strain imaging tool, often limited by beam-induced sample instability for small particles and high power densities. Here, we devise and validate an adapted diffraction volume assembly algorithm, capable of recovering three-dimensional datasets from particles undergoing uncontrolled and unknown rotations. We apply the method to gold nanoparticles which rotate under the influence of a focused coherent x-ray beam, retrieving their three-dimensional shapes and strain fields. The results show that the sample instability problem can be overcome, enabling the use of fourth generation synchrotron sources for Bragg coherent diffraction imaging to their full potential.
RESUMEN
The combination of pediatric multivisceral and kidney transplantation leads to additional recipient risks due to the number of anastomoses and to the small sizes of donor structures. The inclusion of donor kidneys, ureters, and a bladder patch en bloc with multivisceral organs decreases the number and complexity of anastomoses and has not yet been reported. Four patients were transplanted in this fashion; three underwent multivisceral-kidney and one underwent liver-kidney transplantation. The first patient was a 3-year-old male with polycystic kidney disease and congenital hepatic fibrosis. The second was a 7-year-old female with complications from necrotizing enterocolitis. The third was a 12-month-old male with megacystis microcolon intestinal hypoperistalsis syndrome and secondary hydronephrosis, and the fourth was a 3-year-old male with multiple intestinal resections secondary to incarcerated hernia. The third patient developed a right ureteral stenosis with an intact bladder patch. The fourth child expired from maintained abdominal sepsis. The first 3 patients maintained normal graft function. There were no cases of thrombosis, arterial stenosis, or urinary leakages. These reported cases demonstrate that small pediatric en bloc transplantation of the multivisceral organs and dual kidneys with a bladder patch anastomosis is a feasible and less complex alternative to the standard procedure.