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A high-efficiency, high-energy, narrow bandwidth, hundred-nanosecond pulse width 355â nm ultraviolet (UV) laser was realized. A high-energy single-frequency 1064â nm fundamental laser was demonstrated firstly with multistage end-pumped preamplifiers and side-pumped main amplifiers. The corresponding pulse energy, repetition rate, pulse duration, bandwidth, and beam quality factor M2 were determined to be 221â mJ, 100â Hz, 156â ns, 2.25â MHz, and 1.23, respectively. By using type-I phase-matching LBO crystal for second harmonic generation (SHG) and type-II phase-matching LBO crystal for the sum frequency generation of the third harmonic, 67â mJ, a narrow bandwidth 355â nm UV laser was obtained with a pulse width of 137â ns and an energy stability of RMS < 1.2%@2â h. The fundamental to UV optical conversion efficiency was 30.3%. Our results provided a new way for generating high-energy, narrow bandwidth hundred-nanosecond 355â nm UV lasers used for direct-detection Doppler wind lidar (DWL) system.
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Carbon fiber insole (CFI), which is lightweight and stiff to reduce energy loss and help wearers perform better in sports, has recently been introduced. However, reports are scarce on the effects of CFI on sports performance, muscle activation, and wearing comfort. This study investigated the acute effects of CFI on sports performance, lower extremity muscle activity, and subjective comfort. Thirty young healthy males with shoe sizes between 260 and 270 mm performed various sports tasks (power generation, agility, and speed) and treadmill runs with wearable sensors under two experimental insole conditions (benchmark insole as a baseline, CFI). The results showed that, compared to the benchmark insole, CFI significantly improved sports performance in terms of power generation (~1.5%) and agility (~1%). However, it activated more of the Tibialis Anterior (~0.7%) and Gastrocnemius Medialis (~0.8%) muscles, and was perceived to be stiffer and less comfortable. These findings suggested that CFI could improve sports performance, but could cause more lower extremity muscle activation and subjective discomfort.
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Rendimiento Atlético , Masculino , Humanos , Fibra de Carbono , Extremidad Inferior , Músculos , BenchmarkingRESUMEN
With the advancing of location-detection technologies and the increasing popularity of mobile phones and other location-aware devices, trajectory data is continuously growing. While large-scale trajectories provide opportunities for various applications, the locations in trajectories pose a threat to individual privacy. Recently, there has been an interesting debate on the reidentifiability of individuals in the Science magazine. The main finding of Sánchez et al. is exactly opposite to that of De Montjoye et al., which raises the first question: "what is the true situation of the privacy preservation for trajectories in terms of reidentification?" Furthermore, it is known that anonymization typically causes a decline of data utility, and anonymization mechanisms need to consider the trade-off between privacy and utility. This raises the second question: "what is the true situation of the utility of anonymized trajectories?" To answer these two questions, we conduct a systematic experimental study, using three real-life trajectory datasets, five existing anonymization mechanisms (i.e., identifier anonymization, grid-based anonymization, dummy trajectories, k-anonymity and ε-differential privacy), and two practical applications (i.e., travel time estimation and window range queries). Our findings reveal the true situation of the privacy preservation for trajectories in terms of reidentification and the true situation of the utility of anonymized trajectories, and essentially close the debate between De Montjoye et al. and Sánchez et al. To the best of our knowledge, this study is among the first systematic evaluation and analysis of anonymized trajectories on the individual privacy in terms of unicity and on the utility in terms of practical applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s11390-022-2409-x.
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"Chasing" behavior, whereby individuals, driven by a desire to break even, continue a risky activity (RA) despite incurring large losses, is a commonly observed phenomenon. We examine whether the desire to break even plays a wider role in decisions to stop engaging in financially motivated RA in a naturalistic setting. We test hypotheses, motivated by this research question, using a large data set: 707,152 transactions of 5,379 individual financial market spread traders between September 2004 and April 2013. The results indicate strong effects of changes in wealth around the break-even point on the decision to cease an RA. An important mediating factor was the individual's historical long-term performance. Those with a more profitable trading history were less affected by a fall in cash balance below the break-even point compared to those who had been less profitable. We observe that break-even points play an important role in the decision of nonpathological risk takers to stop RAs. It is possible, therefore, that these nonpathological cognitive processes, when occurring in extrema, may result in pathological gambling behavior such as "chasing." Our data set focuses on RAs in financial markets and, consequently, we discuss the implications for institutions and regulators in the effective management of risk taking in markets. We also suggest that there may be a need to consider carefully the nature and role of "break-even points" associated with a broader range of nonfinancially-focused risk-taking activities, such as smoking and substance abuse.
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Inversiones en Salud , Asunción de Riesgos , Conducta Adictiva , Comercio , Economía , Juego de Azar , Humanos , Probabilidad , Psicometría , Riesgo , Reino UnidoRESUMEN
Two-dimensional (2D) violet phosphorus (VP) plays a significant role in the applications of photonic and optoelectronic devices due to its unique optical and electrical properties. The ultrafast carrier dynamics and nonlinear optical absorption properties were systematically investigated here. The intra- and inter-band ultrafast relaxation times of 2D VP nanosheets were measured to be ~6.83 ps and ~62.91 ps using the pump-probe method with a probe laser operating at 1.03 µm. The nonlinear absorption coefficient ßeff, the saturation intensity Is, the modulation depth ΔR, and the nonsaturable loss were determined to be -2.18 × 104 cm/MW, 329 kW/cm2, 6.3%, and 9.8%, respectively, by using the Z-scan and I-scan methods, indicating the tremendous saturable absorption property of 2D VP nanosheets. Furthermore, the passively Q-switched Nd:YVO4 laser was realized with the 2D VP nanosheet-based SA, in which the average output power of 700 mW and the pulse duration of 478 ns were obtained. These results effectively reveal the nonlinear optical absorption characteristics of VP nanosheets, demonstrating their outstanding light-manipulating capabilities and providing a basis for the applications of ultrafast optical devices. Our results verify the excellent saturable absorption properties of 2D VP, paving the way for its applications in pulsed laser generation.
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Industrial exoskeletons are developed to relieve workers' physical demands in the workplace and to alleviate ergonomic issues associated with work-related musculoskeletal disorders. As a safe and economical alternative to empirical/experimental methods, modelling is considered as a powerful tool for design and evaluation of industrial exoskeletons. This systematic review aims to provide a comprehensive understanding of the current literature on the design and evaluation of industrial exoskeletons through modelling. A systematic study was conducted by general keyword searches of five electronic databases over the last two decades (2003-2022). Out of the 701 records initially retrieved, 33 eligible articles were included and analyzed in the final review, presenting a variety of model inputs, model development, and model outputs used in the modelling. This systematic review study revealed that existing modelling methods can evaluate the biomechanical and physiological effects of industrial exoskeletons and provide some design parameters. However, the modelling method is currently unable to cover some of the main evaluation metrics supported by experimental assessments, such as task performance, user experience/discomfort, change in metabolic costs etc. Standard guidelines for model construction and implementation, as well as validation of human-exoskeleton interactions, remain to be established.
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Dispositivo Exoesqueleto , Enfermedades Musculoesqueléticas , Humanos , Industrias , Enfermedades Musculoesqueléticas/etiología , Enfermedades Musculoesqueléticas/prevención & control , Lugar de Trabajo , ErgonomíaRESUMEN
OBJECTIVE: This paper proposes a novel application of data augmentation to address various rotation errors of wearable sensors for robust pre-impact fall detection. In such systems, sensor rotation errors are inevitable because of loose attachment and body movement during long deployment. METHODS: Two augmented models with uniform and normal strategies were compared with a non-augmented model on the original dataset (no rotation error) and a validation dataset (with rotation error). The validation dataset was constructed with three types of rotation errors, namely, pitch, roll, and compound roll and pitch (CRP) at three levels of range (low: 15°, medium: 30°, and high: 45°). RESULTS: Five-fold cross validation showed the two augmented models maintained accuracy (>98.5%) as high as the non-augmented model on the original dataset but showed considerable improvements of 6.11% and 6.50% on the validation dataset, respectively. CRP error negatively affected the model accuracy the most, followed by pitch and then roll errors. In addition, the normal model had advantages over the uniform model in the low-to-medium range of error, which is expected to be the typical error range in practical applications. As for lead time, similarly, the augmented models achieved performance similar to the non-augmented model on the original dataset but showed significant improvements on the validation dataset. CONCLUSION AND SIGNIFICANCE: Data augmentation had notable capacities to address sensor rotation errors for practical applications and augmented models especially the normal model showed good potential to be embedded in a wearable system for robust pre-impact fall detection and injury prevention.
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Accidentes por Caídas , Dispositivos Electrónicos Vestibles , Humanos , Accidentes por Caídas/prevención & control , Movimiento , RotaciónRESUMEN
PURPOSE: Hantavirus infections cause severe haemorrhagic fever with renal syndrome (HFRS) in humans and are associated with high fatality rates. In 2017, numerous outbreaks were reported in China and Germany. This represents a significant public-healthcare issue with no effective HFRS vaccines that offer a long-term immune response. In this study, we investigated the long-term humoral and cellular immune responses and protective immunity of Hantaan virus (HTNV) granulocyte-macrophage colony stimulating factor (GM-CSF) and CD40 ligand (CD40L) virus-like particles (VLPs) in mice. METHODOLOGY: GM-CSF and CD40L VLPs were constructed via co-transfection of pCI-S and pCI-M-CD40L, and pCI-S and pCI-M-GM-CSF, into dihydrofolatereductase (dhfr)-deficient Chinese hamster ovary cells, respectively. Mice were immunized with HTNV VLPs 2 weeks apart. The animals were challenged 6 months after immunization. Specific and neutralizing antibodies were assessed by ELISA; IFN-γ was measured by enzyme-linked immunospot (ELISpot) assay and effectiveness by cytotoxic T lymphocyte (CTL) cytotoxicity assays. Nucleic acid loads of HTNV were tested by quantitative real-time PCR and viral antigen was detected via indirect ELISA. Pathological alterations were detected via haematoxylin-eosin staining. RESULTS: GM-CSF and CD40L VLPs provided stable, long-term protection with a high titre of neutralizing antibody in mice 6 months after immunization. Furthermore, VLPs increased HTNV-specific cellular immune responses via higher expression of IFN-γ and CTL responses. HTNV challenge assay results showed long-term protection against HFRS. No significant pathological alteration was observed in the organs of mice after immunization. CONCLUSION: This is, to the best of our knowledge, the first report demonstrating the long-term potency of HTNV VLP vaccines against HTNV infection and offers new insights into HTNV vaccine development.
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Ligando de CD40/genética , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Infecciones por Hantavirus/prevención & control , Vacunas de Partículas Similares a Virus/inmunología , Animales , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Antígenos Virales/inmunología , Ligando de CD40/administración & dosificación , Células CHO , Cricetulus , Ensayo de Inmunoadsorción Enzimática , Femenino , Factor Estimulante de Colonias de Granulocitos y Macrófagos/administración & dosificación , Virus Hantaan/genética , Infecciones por Hantavirus/inmunología , Inmunidad Celular , Inmunidad Humoral , Ratones , Ratones Endogámicos C57BL , Transfección , Vacunas de Partículas Similares a Virus/genéticaRESUMEN
The cytotoxic T lymphocyte (CTL) response plays a key role in controlling viral infection, but only a few epitopes within the HTNV glycoprotein (GP) that are recognized by CTLs have been reported. In this study, we identified one murine HTNV GP-derived H2-Kb-restricted CTL epitope in C57BL/6 mice, which could be used to design preclinical studies of vaccines for HTNV infection. First, 15 8-mer peptides were selected from the HTNV GP amino acid sequence based on a percentile rank of <=1% by IEDB which is the most comprehensive collection of epitope prediction and analysis tool. A lower percentile rank indicates higher affinity and higher immune response. In the case of the consensus method, we also evaluated the binding score of peptide-binding affinity by the BIMAS software to confirm that all peptides were able to bind H2-Kb. Second, one novel GP-derived CTL epitope, GP6 aa456-aa463 (ITSLFSLL), was identified in the splenocytes of HTNV-infected mice using the IFN-γ ELISPOT assay. Third, a single peptide vaccine was administered to C57BL/6 mice to evaluate the immunogenic potential of the identified peptides. ELISPOT and cell-mediated cytotoxicity assays showed that this peptide vaccine induced a strong IFN-γ response and potent cytotoxicity in immunized mice. Last, we demonstrated that the peptide-vaccinated mice had partial protection from challenge with HTNV. In conclusion, we identified an H2-Kb-restricted CTL epitope with involvement in the host immune response to HTNV infection.
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Epítopos de Linfocito T/inmunología , Antígenos H-2/aislamiento & purificación , Antígenos H-2/farmacología , Virus Hantaan/inmunología , Fiebre Hemorrágica con Síndrome Renal/prevención & control , Linfocitos T Citotóxicos/inmunología , Secuencia de Aminoácidos , Animales , Antígenos Virales/análisis , Antígenos Virales/inmunología , Linfocitos T CD4-Positivos , Linfocitos T CD8-positivos , Línea Celular , Citocinas/análisis , Pruebas Inmunológicas de Citotoxicidad , Modelos Animales de Enfermedad , Ensayo de Immunospot Ligado a Enzimas/métodos , Femenino , Glicoproteínas/efectos de los fármacos , Glicoproteínas/inmunología , Virus Hantaan/genética , Virus Hantaan/patogenicidad , Fiebre Hemorrágica con Síndrome Renal/virología , Inmunización , Interferón gamma/análisis , Ratones , Ratones Endogámicos C57BL , ARN Viral/aislamiento & purificación , Bazo/inmunología , Bazo/patología , Vacunas de Subunidad/inmunología , Vacunas SintéticasRESUMEN
Infection of Hantaan virus (HTNV) usually causes hemorrhagic fever with renal syndrome (HFRS). China has the worst epidemic incidence of HFRS as well as high fatality. Inactivated whole virus has been used for HFRS vaccination, however there are still problems such as safety concerns. CD40 ligand (CD40L) and granulocyte macrophage colony-stimulating factor (GM-CSF) are well-known immune stimulating molecules that can enhance antigen presenting, lymphocytes activation and maturation, incorporation of CD40L and GM-CSF to the surface of virus like particles (VLPs) can greatly improve the vaccination effect. We constructed eukaryotic vectors expressing HTNV M segment and S segment, as well as vectors expressing HTNV M segment with CD40L or GM-CSF, our results showed successful production of CD40L or GM-CSF incorporated HTNV VLPs. In vitro stimulation with CD40L or GM-CSF anchored HTNV VLP showed enhanced activation of macrophages and DCs. CD40L/GM-CSF incorporated VLP can induce higher level of HTNV specific antibody and neutralizing antibody in mice. Immunized mice splenocytes showed higher ability of secreting IFN-γ and IL-2, as well as enhancing CTL activity. These results suggest CD40L/GM-CSF incorporated VLP can serve as prospective vaccine candidate.