Quantifying the effects of sleep loss: relative effect sizes of the psychomotor vigilance test, multiple sleep latency test, and maintenance of wakefulness test

The psychomotor vigilance test (PVT) is a widely-used, minimally invasive, inexpensive, portable, and easy to administer behavioral measure of vigilance that is sensitive to sleep loss. We conducted analyses to determine the relative sensitivity of the PVT vs. the multiple sleep latency test (MSLT) and the maintenance of wakefulness test (MWT) during acute total sleep deprivation (TSD) and multiple days of sleep restriction (SR) in studies of healthy adults. Twenty-four studies met the criteria for inclusion. Since sleepiness countermeasures were administered in some of these studies, the relative sensitivity of the three measures to these interventions was also assessed. The difference in weighted effect size (eta-squared) was computed for each pair of sleepiness measures based on available raw test data (such as average PVT reaction time). Analyses revealed that the sleep measures were differentially sensitive to various types of sleep loss over time, with MSLT and MWT more sensitive to TSD than the PVT. However, sensitivity to SR was comparable for all three measures. The PVT and MSLT were found to be differentially sensitive to the administration of sleepiness countermeasures (drugs, sleep loss, etc.), but PVT and MWT were found to be comparably sensitive to these interventions. These findings suggest the potential utility of the PVT as a component of next-generation fatigue risk management systems.

Design of a Highly Sensitive Photonic Crystal Fiber Sensor for Sulfuric Acid Detection

In this research, a photonic crystal fiber (PCF)-based sulfuric acid detector is proposed and investigated to identify the exact concentration of sulfuric acid in a mixture with water. In order to calculate the sensing and propagation characteristics, a finite element method (FEM) based on COMSOL Multiphysics software is employed. The extensive simulation results verified that the proposed optical detector could achieve an ultra-high sensitivity of around 97.8% at optimum structural and operating conditions. Furthermore, the proposed sensor exhibited negligible loss with suitable numerical aperture and single-mode propagation at fixed operating conditions. In addition, the circular air holes in the core and cladding reduce fabrication complexity and can be easily produced using the current technology. Therefore, we strongly believe that the proposed detector will soon find its use in numerous industrial applications.

Tailoring of upconversion luminescence of Al3+engineered titanate phosphor for non-invasive thermometry

The ability of rare-earth-doped ferroelectric oxides to achieve outstanding upconversion (UC) performances under NIR irradiation despite possessing intrinsic electric properties drives researchers all over the globe to work in this field. The structural and spectroscopic characteristics of the Bi4Ti3O12 phosphor integrated with Er3+, Yb3+, and Al3+ have been thoroughly investigated in this study. The considerable increase in UC emission ~three times caused by the addition of Al3+ ions has been observed and discussed. The processes connected with the UC emission related to the pump power variation have been realized using the rate law equation. Aside from having high sensitivity of 0.011 K-1 at room temperature, the prepared phosphor possesses excellent thermal stability, i.e., it retains ~ 73% of its initial intensity with the addition of Al3+ ions.

Down-conversion luminescence and temperature sensing characteristics of LaSrGaO4 :Er3

Erbium(III) ion (Er³⁺ ) has abundant energy levels that can emit light covering a quite broad wavelength range in many hosts. Here we synthesized LaSrGaO₄ :Er³⁺ phosphors by a high-temperature solid-state method. Upon excitation at the ultraviolet (UV) band, LaSrGaO₄ :Er³⁺ phosphors could emit green, red and near-infrared emission simultaneously. The temperature dependent emission characteristics of the as-prepared samples was then studied and two kinds of luminescent ratiometric thermometry were constructed. The first one is on the basis of two green emission bands that stems from the ² H_11/2  → ⁴ I_15/2 and ⁴ S_3/2  → ⁴ I_15/2 transitions of Er³⁺ . The intensity ratio between these two emission bands was found to follow well with the Boltzmann distribution, and its maximum relative sensitivity was calculated to be 0.84% K^-1 at 299 K. The other one depends on the ⁴ F_9/2  → ⁴ I_15/2 transition of Er³⁺ and self-luminescence of the host LaSrGaO₄ , considering that these two emission lines have different temperature response. The relative sensitivity of this type of luminescence intensity ratio (LIR) thermometry could reach 1.86% K^-1 at 299 K, we have successfully developed materials with one of the largest relative sensitivities to date, which provides some basis for the subsequent development of a new type of non-contact temperature sensor.

A Highly Birefringent Photonic Crystal Fiber for Terahertz Spectroscopic Chemical Sensing

A photonic crystal fiber (PCF) with high relative sensitivity was designed and investigated for the detection of chemical analytes in the terahertz (THz) regime. To ease the complexity, an extremely simple cladding employing four struts is adopted, which forms a rectangular shaped core area for filling with analytes. Results of enormous simulations indicate that a minimum 87.8% relative chemical sensitivity with low confinement and effective material absorption losses can be obtained for any kind of analyte, e.g., HCN (1.26), water (1.33), ethanol (1.35), KCN (1.41), or cocaine (1.50), whose refractive index falls in the range of 1.2 to 1.5. Besides, the PCF can also achieve high birefringence (∼0.01), low and flat dispersion, a large effective modal area, and a large numerical aperture within the investigated frequency range from 0.5 to 1.5 THz. We believe that the proposed PCF can be applied to chemical sensing of liquid and THz systems requiring wide-band polarization-maintaining transmission and low attenuation.

Thermochromic Luminescent Nanomaterials Based on Mn4+/Tb3+ Codoping for Temperature Imaging with Digital Cameras

A new thermographic nanocrystalline Sr4Al14O25:Mn4+,Tb3+ phosphor was developed, and the concentrations of both dopants and the synthesis conditions were optimized. The combination of the thermally quenched luminescence from the Mn4+ ions to the almost temperature-independent emission from Tb3+ provides a sensitive luminescent thermometer (SR = 2.8%/°C at 150 °C) with strong emission color variability. In addition, a figure of merit for this luminescence thermochromism was proposed, as the relative sensitivities of the x and y CIE coordinates, which for this phosphor reaches at 150 °C SR(x) = 0.6%/°C and SR(y) = 0.4%/°C, respectively. Noncontact thermal imaging was demonstrated with this phosphor using a single consumer digital camera and exploiting the ratio of red (R) and green (G) channels of the RGB images, thereby confirming the high application potential of Sr4Al14O25:Mn4+,Tb3+ nanocrystals for thermal sensing and mapping.

A method for screening climate change-sensitive infectious diseases

Climate change is a significant and emerging threat to human health, especially where infectious diseases are involved. Because of the complex interactions between climate variables and infectious disease components (i.e., pathogen, host and transmission environment), systematically and quantitatively screening for infectious diseases that are sensitive to climate change is still a challenge. To address this challenge, we propose a new statistical indicator, Relative Sensitivity, to identify the difference between the sensitivity of the infectious disease to climate variables for two different climate statuses (i.e., historical climate and present climate) in non-exposure and exposure groups. The case study in Anhui Province, China has demonstrated the effectiveness of this Relative Sensitivity indicator. The application results indicate significant sensitivity of many epidemic infectious diseases to climate change in the form of changing climatic variables, such as temperature, precipitation and absolute humidity. As novel evidence, this research shows that absolute humidity has a critical influence on many observed infectious diseases in Anhui Province, including dysentery, hand, foot and mouth disease, hepatitis A, hemorrhagic fever, typhoid fever, malaria, meningitis, influenza and schistosomiasis. Moreover, some infectious diseases are more sensitive to climate change in rural areas than in urban areas. This insight provides guidance for future health inputs that consider spatial variability in response to climate change.