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BackgroundAn extensive amount of information related to the novel coronavirus (COVID-19) pandemic was disseminated by mass and social media in China. To date, there is limited evidence on how this infodemic may influence psychobehavioral responses to the crisis. ObjectiveThe aim of this study is to assess the psychobehavioral responses to the COVID-19 outbreak and examine their associations with mass and social media exposure. MethodsA cross-sectional study among medical and health sciences students from the Fujian Medical University in Fuzhou, China, was conducted between April 6-22, 2020. ResultsA total of 2086 completed responses were received. Multivariable analyses demonstrated that four constructs of the Health Belief Model (HBM)—higher perception of susceptibility (odds ratio [OR] 1.44; 95% CI 1.07-1.94), severity (OR 1.32; 95% CI 1.10-1.59), self-efficacy (OR 1.61; 95% CI 1.21-2.15), and perceived control or intention to carry out prevention measures (OR 1.32; 95% CI 1.09-1.59)—were significantly associated with a higher mass media exposure score, whereas only three constructs—higher perception of severity (OR 1.43; 95% CI 1.19-1.72), self-efficacy (OR 1.85; 95% CI 1.38-2.48), and perceived control or intention to carry out prevention measures (OR 1.32; 95% CI 1.08-1.58)—were significantly associated with a higher social media exposure score. Lower emotional consequences and barriers to carry out prevention measures were also significantly associated with greater mass and social media exposure. Our findings on anxiety levels revealed that 38.1% (n=795; 95% CI 36.0-40.2) of respondents reported moderate-to-severe anxiety. A lower anxiety level was significantly associated with higher mass and social media exposure in the univariable analyses; however, the associations were not significant in the multivariable analyses. ConclusionsIn essence, both mass and social media are useful means of disseminating health messages and contribute to the betterment of psychobehavioral responses to COVID-19. Our findings stress the importance of the credibility of information shared through mass and social media outlets and viable strategies to counter misinformation during a pandemic.

BackgroundThe incidence of cancer pain increases in discharged patients because of discontinued standard treatments and reductions in medication adherence. Motivated by the need for better pain management in discharged patients, we developed a mobile phone app (Pain Guard) to provide continuous treatment information and feedback to discharged cancer patients suffering from pain. ObjectiveThe aim was to design, construct, and test the Pain Guard app in patients managing cancer pain, evaluate the total remission rate of pain and the improvement in quality of life (QoL) to improve pain management for cancer pain patients, and assess patient acceptance of the app. MethodsThis randomized controlled double-arm study involved 58 patients with cancer pain symptoms. Participants were randomly assigned to a group receiving care through the Pain Guard app (n=31) or to a control group (n=27) who received only traditional pharmaceutical care. In a pretest, participants were rated using a baseline cancer pain assessment and QoL evaluation. During treatment, the consumption levels of analgesic drugs were recorded every week. After a 4-week study period, another round of cancer pain assessment and QoL evaluation was conducted. The system’s usability, feasibility, app compliance, and satisfaction were also assessed. Our primary outcome was remission rate of pain, and secondary outcomes were medication adherence, improvements in QoL, frequency of breakthrough cancer pain (BTcP), incidence of adverse reactions, and satisfaction of patients. ResultsAll participants (N=58) successfully completed the study. There were no significant differences in baseline pain scores or baseline QoL scores between groups. At the end of the study, the rate of pain remission in the trial group was significantly higher than that in the control group (P

In contrast to conventional anti‐counterfeiting technologies, which are susceptible to decryption and exhibit limited effectiveness, the utilization of light to dynamically configure soft materials in a fully reversible and programmable manner not only enhances data security but also improves anti‐counterfeiting performance. However, achieving precise control over reflection structural colors and laser wavelengths within a broad dynamic range remains a challenge. In this study, a UV‐responsive soft helical superstructure is established by combining a photochromic compound with chiral liquid crystals (LCs). By manipulating the Bragg reflection angle, structural reflection colors ranging from red to cyan are successfully achieved. The introduction of an anti‐counterfeiting technique that embeds diverse micro‐structures provides features such as color adjustability, erasability, and angle‐dependent stability. Using the unique properties of this soft helical superstructure, the implementation of a wavelength‐tunable LC bandgap laser through optically reconfigurable Förster resonance energy transfer processes is showcased. Furthermore, a straightforward prototype information encoder is developed to mimic the processes of information encoding and decoding, bypassing the need for complex algorithm design. This research underscores the practicality of LC helical soft systems, emphasizing their distinctive responsiveness to light and their applicability in optical programming photonics. [ABSTRACT FROM AUTHOR]

Liquid‐crystal random lasers (LCRLs) represent a burgeoning field in soft‐matter photonics, holding promise for ushering in an era of ultrathin, versatile laser sources. Such lasers encompass a multitude of remarkable features, including wide‐band tunability, large coherence area and, in some cases, multidirectional emission. In this paper, an LCRL is developed by doping a laser dye, pyrromethene 597 (PM597), into cholesteric LC, but achieving a wide‐range wavelength‐controllable (560–720 nm) bandgap lasing through voltage control. Bandgap lasing intriguingly occurs in media with extremely low dye gain, which is mainly contributed by the extremely high photon density of states (DOS) at the edge of the LC bandgap. In addition, the utilization rate of the fluorescence spectrum (550–750 nm) of laser dye PM597 is as high as 80%. The multivariate linear regression model is used to characterize the inherent relationship between the lasing intensity emitted by LC and the photon DOS, fluorescence quantum yield, and internal scattering under specific pumping energy. This model shows the potential to predict the critical conditions of laser emission accurately and provides the capability to design and fabricate large‐scale multifunctional responsive photonic crystals using a simple fabrication procedure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Based on coupling colloidal semiconductor quantum dots to plasmonic nanorod arrays, low-threshold random lasers with controlled emission modes are realized. • The incoherent and coherent emission modes can be controlled by varying the filling configurations of nanorods. • The resonant cavity modes of plasmonic nanorod arrays can reduce the thresholds of random lasers. Random lasers based on scattering for light amplification have gained extensive attention due to their simple structures. Colloidal semiconductor quantum dots (CSQDs) are excellent candidates as active media for random lasing. However, achieving CSQDs-based random lasers is challenging because the non-radiative Auger recombination produces a remarkable carrier loss. Here, we report random lasers with low thresholds based on the CSQDs coupled to the plasmonic nanorod arrays. The random lasers result from the enhancing excitation and emission rates of the CSQDs through plasmon resonance energy transfer induced by the spectral overlap between the resonant cavity modes of the plasmonic nanorod arrays and the excitons of the CSQDs, which reduces the carrier loss and establishes the optical gain in the CSQDs. Moreover, the incoherent and coherent emission modes can be controlled by varying the filling configurations (i.e., full-filling and partial-filling) of the plasmonic nanorods embedded in anodic aluminum oxide templates. Consequently, the incoherent random laser with a threshold of 19.3 μJ/mm2 and coherent random lasers with a threshold of 13.5 μJ/mm2 are performed, respectively. The proposed system provides a feasible method for low-threshold CSQDs-based random lasers with controlled emission modes, showing a promising avenue for potential applications. [ABSTRACT FROM AUTHOR]

In this paper, a wavelength division multiplexing (WDM) visible light communication (VLC) system based on the perovskite quantum dots (QDs) with two different fluorescence wavelengths is demonstrated. This system consists of a transmitter, free space channel and a receiver. The NRZ-OOK (non-return-zero on-off-keying) signals are transmitted in this channel to achieve WDM visible light communication at a transmission distance of 60 cm, with a maximum transmission capacity of 100 Mbps in the field of view of 80°. In addition, computational temporal ghost imaging (CTGI) algorithm is used to reduce the bit error rate (BER) of the received signals and improve maximum transmission angle to 120°. The proposed WDM system paves the way for visible light communication in free space. • A wavelength division multiplexing (WDM) visible light communication (VLC) based on perovskite quantum dots with two different fluorescence wavelengths is demonstrated. • This system achieve WDM VLC with a maximum transmission capacity of 100 Mbps in the field of view of 80°. • The computational temporal ghost imaging (CTGI) algorithm is used to improve the demodulated signal quality, and significantly reduces the BER of communication and increases the maximum angle to 120°. [ABSTRACT FROM AUTHOR]

• A tunable narrow linewidth fiber ring laser based on parity-time (PT) symmetric double rings and variable optical attenuator (VOA) is demonstrated. • By tuning the VOA, the single-longitudinal-mode oscillation can be achieved when the PT symmetric is broken. • The tunable laser can be tuned from 1525 nm to 1563 nm, and the linewidth of the laser is at the sub-kHz level in the whole tuning process. A tunable narrow linewidth fiber ring laser based on parity-time (PT) symmetric double rings and variable optical attenuator (VOA) is demonstrated. The laser is composed of a fiber loop mirror (FLM), which creates two coupled rings: the reflective ring and the transmissive ring. The loss of the transmissive ring can be controlled by tuning the VOA, which balances with the gain of the reflective ring. When the PT symmetry is broken, a single-longitudinal-mode (SLM) laser is realized. The laser can be tuned by an optical tunable filter (OTF), and the tuning range is 38 nm, spanning from 1525 nm to 1563 nm. In the whole tuning process, the linewidth of the laser is at the sub-kHz level, and the optical signal to noise ratios (OSNR) is over 53 dB. The fluctuation of wavelength and power are less than 0.02 nm and 0.52 dB in an hour, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Luminescent down shifting (LDS) technique is one effective way to improve the poor response of multi-crystalline silicon (mc-Si) photovoltaic (PV) modules at short wavelength less than 400nm. Eu3+ complexes are effective LDS species for PV modules due to their large stokes’ shift and high luminescent quantum efficiency (LQE). Although Eu3+ complexes have been utilized in PV modules as LDS species widely, they have not been encapsulated into the pre-existing poly-ethylene vinyl acetate (EVA) layer of modules between glass and solar cell by now. The aim of our work is to enhance the performance of mc-Si PV modules by encapsulating high efficient Eu3+ complexes into their pre-existing EVA layers which would not modify the well-established manufacturing process for PV modules. In this work, two Eu3+ complexes with different absorption spectrum were encapsulated into the commercial EVA layer by soaking method for the first time and used in the encapsulation of mc-Si PV modules. Hereinto, Eu(TTA)3(TPPO)2 (TTA=2-thenoyltrifluoroacetonate, TPPO=triphenylphosphine oxide) (EuTT) with absorption spectrum less than 400nm and high LQE (0.73) improves the external quantum efficiency of mc-Si PV module from 0.05 to 0.20, which produces a 0.42% increases in its power conversion efficiency. In addition, it is found that the enhancement brought by Eu(TTA)3(TPPO)2 can reduce cost of power generated by mc-Si devices from US$1/W p to US$0.98/W p according to the calculation. Therefore, Eu(TTA)3(TPPO)2 as LDS species with high LQE and low cost is promising for enhancing the performance of mc-Si PV modules in practical application. [Copyright &y& Elsevier]

We conducted an investigation on a flexible random laser (RL) device featuring non-noble plasmonic enhancement and scattering. The RL device was created by integrating copper nanowires (Cu NWs) and laser dyes (rhodamine 6G, R6G) into an acrylamide (AM) hydrogel matrix. The substantial overlap between the plasmonic resonance of Cu NWs and the emission of R6G effectively mitigates the requirements for lasing generation. Furthermore, the robust scattering induced by the three-dimensional distribution of Cu NWs contributes to a reduction in the laser threshold. Notably, the unique properties of the AM hydrogel ensure that the laser device exhibits excellent tensile recovery performance. The RL device is capable of maintaining stable lasing performance even after 100 % tensile deformation. This flexible laser device offers the advantages of a straightforward fabrication process, low cost, and robust lasing characteristics, thus paving the way for their advanced application in the future. [Display omitted] • A flexible hydrogel-based random laser that utilizes the plasmonic enhancement effect of non-noble metals was developed. • The threshold of random laser is effectively reduced by the local surface plasmon resonance effect of copper nanowires. • The random laser can maintain stable and high-quality laser output even after 100 % tensile deformation. [ABSTRACT FROM AUTHOR]

• Based on the dye-doped hydrogel material, a low-threshold flexible film as well as a fiber random laser were realized. • Both random lasers in this paper can tune the wavelength of the random laser under the condition of changing the temperature. • Both hydrogel films and fiber random lasers have excellent flexibility and mechanical toughness, and the threshold of random lasers can be reduced by bending or stretching them. Hydrogel materials have great applications in biomedical and flexible optical sensors due to their good flexibility and biocompatibility. In this paper, two hydrogel structures of dye-doped poly(acrylamide-co-poly(ethylene glycol) diacrylate) (p(AM-co-PEGDA)) films and optical fibers were prepared to obtain low threshold and flexible random lasers. The random laser is attributed to the light scattering from the porous structure of the hydrogel, and the random lasing wavelength can be tuned of ∼ 7 nm and ∼ 11.8 nm for the hydrogel film and fiber in the temperature range of 25 to 85 °C, respectively. In addition, the hydrogel film can be bent repeatedly, and the bending strain has a positive effect on the random laser, and the random laser threshold is reduced by 10 μJ/mm2 when the bending strain reaches 47 % for hydrogel film. When the hydrogel optical fiber is stretched to 15 % of its original length, the random laser threshold can be reduced by 12 μJ/mm2.The p(AM-co-PEGDA) hydrogel optical fiber structure has better temperature sensing performance and excellent flexibility than the thin film structure. This work paves a way to extend random laser applications to photothermal therapy, ion detection, and biosensing. [ABSTRACT FROM AUTHOR]

• In optic fiber sensing field, it shows the highest magnetic field sensitivity of 23.7425 nm/mT under magnetic field lower than 3mT. • The sensitivity is 250 times and 13.9 times than ordinary long period fiber grating and tapered fiber. • Dual-peaks-MTLPG (taper-long-period-fiber-grating-filled-with magnetic fluid) realizes the two parameters demodulation in the different range of magnetic field. The high sensitivity and dual parameters tapered-long-period-fiber-grating filled magnetic fluid (MTLPG) sensor is proposed in this paper. The tapered-long period fiber grating (TLPG) with double peaks was obtained by exposing periodically in the taper waist region of the taped fiber by using CO 2 laser. The magnetic fluid (MF)was wrapped on the taper cone surface of TLPG to obtain a magnetic field and temperature double responsive MTLPG sensor. According to the two resonance wavelengths responsive difference of MTLPG for the magnetic field and temperature, the sensitivity matrix including magnetic and temperature parameters can be constructed to solve the cross-sensitivity problem. The proposed MTLPG sensor has different responsive ranges and sensitivity according to the different MF concentrations and MTLPG cone diameters. The maximum sensitivity of our proposed sensor can reach to 23.72 nm/mT and 0.52 nm/℃, while the maximum responsive range can reach at 8.0 ∼ 16.0 mT and 25 ∼ 75 ℃. As far as we known, this is the highest magnetic sensitivity of optic fiber sensors in a weak magnetic field (below 3mT).Therefore, according the excellent characteristic for high sensitivity in a weak magnetic field and wide range temperature detection without crosstalk. [ABSTRACT FROM AUTHOR]

• A new method is presented to measure slow flow velocity based on self-mixing effect. • Flow velocity is obtained by the frequency difference from asymmetric power spectrum. • This scheme can be applied for direction determination of the flow velocity. • The maximum achievable Doppler shift within the pipe is measured as low as 15.37 Hz. In this study, an all-fiber structure self-mixing sensor using a distributed feedback Bragg (DFB) fiber laser as the light source is proposed to measure flow velocity. In pursuit of slower flow velocity, the external cavity frequency-shifting optical technique is introduced into the optical sensing system to effectively avoid complex noises existing in the low-frequency region. Furthermore, the additional bonus is that the identification of the velocity direction can be obtained by the asymmetric shape near the feedback frequency shift on the spectrum. At the same time, a suitable solution is developed for extraction of the characteristic feature parameters from the asymmetrical spectrum of the flow velocity signal. It was demonstrated the actual conformity of the measurement results by means of this new approach of data processing. According to the practical experimental measurements, the maximum measurable Doppler shift concerning the slow fluid can be obtained as low as 15.37 Hz. This indicates that the designed all-fiber laser self-mixing flow velocity meter can be prospectively extended to slow fluid measurement associated with the related sensing and medical applications. [ABSTRACT FROM AUTHOR]

We have demonstrated a low threshold and tunable flexible random laser (RL) in dye-doped poly ethylene glycol diacrylate (PEG-DA) hydrogel, which was prepared by crosslinking polymerization using PEG-DA monomer and photoinitiator. The random lasering is attributed to the light scattering from the porous structure of hydrogels, and the wavelength of random lasing can be tuned by ~3.2 nm in the temperature range from 30 °C to 70 °C. Under the continuous increasing and decreasing temperature cycle, the random lasing tunable phenomenon can still be observed, which proves that this flexible material can be used as a new temperature sensor. In addition, we also explored the application of flexible laser in phototherapy. Considering the good elasticity and transparency of hydrogels, this thermo-responsive property will be of great significance to the biomedical applications of flexible material. • Lower threshold and cost than other lasers. • A good ability of temperature control emission wavelength. • Broad prospect of phototherapy based on flexible and biocompatible materials. [ABSTRACT FROM AUTHOR]