As the global population continues to age, effective management of longevity risk becomes increasingly critical for various stakeholders. Accurate mortality forecasting serves as a cornerstone for addressing this challenge. This study proposes to leverage Kernel Principal Component Analysis (KPCA) to enhance mortality rate predictions. By extending the traditional Lee-Carter model with KPCA, we capture nonlinear patterns and complex relationships in mortality data. The newly proposed KPCA Lee-Carter algorithm is empirically tested and demonstrates superior forecasting performance. Furthermore, the model’s robustness was tested during the COVID-19 pandemic, showing that the KPCA Lee-Carter algorithm effectively captures increased uncertainty during extreme events while maintaining narrower prediction intervals. This makes it a valuable tool for mortality forecasting and risk management. Our findings contribute to the growing body of literature where actuarial science intersects with statistical learning, offering practical solutions to the challenges posed by an aging world population.

To meet the demands of laser-ion acceleration at a high repetition rate, we have developed a comprehensive diagnostic system for real-time and in situ monitoring of liquid sheet targets (LSTs). The spatially resolved rapid characterizations of an LST’s thickness, flatness, tilt angle and position are fulfilled by different subsystems with high accuracy. With the help of the diagnostic system, we reveal the dependence of thickness distribution on collision parameters and report the 238-nm liquid sheet generated by the collision of two liquid jets. Control methods for the flatness and tilt angle of LSTs have also been provided, which are essential for applications of laser-driven ion acceleration and others.

Here, we report the generation of MeV alpha-particles from H-11B fusion initiated by laser-accelerated boron ions. Boron ions with maximum energy of 6 MeV and fluence of 109/MeV/sr@5 MeV were generated from 60 nm-thick self-supporting boron nanofoils irradiated by 1 J femtosecond pulses at an intensity of 1019 W/cm2. By bombarding secondary hydrogenous targets with the boron ions, 3 × 105/sr alpha-particles from H-11B fusion were registered, which is consistent with the theoretical yield calculated from the measured boron energy spectra. Our results demonstrated an alternative way toward ultrashort MeV alpha-particle sources employing compact femtosecond lasers. The ion acceleration and product measurement scheme are referential for the studies on the ion stopping power and cross section of the H-11B reaction in solid or plasma.

Post-acceleration of protons in helical coil targets driven by intense, ultrashort laser pulses can enhance ion energy by utilizing the transient current from the targets’ self-discharge. The acceleration length of protons can exceed a few millimeters, and the acceleration gradient is of the order of GeV/m. How to ensure the synchronization between the accelerating electric field and the protons is a crucial problem for efficient post-acceleration. In this paper, we study how the electric field mismatch induced by current dispersion affects the synchronous acceleration of protons. We propose a scheme using a two-stage helical coil to control the current dispersion. With optimized parameters, the energy gain of protons is increased by four times. Proton energy is expected to reach 45 MeV using a hundreds-of-terawatts laser, or more than 100 MeV using a petawatt laser, by controlling the current dispersion.

Carbon nanotube foams (CNFs) have been successfully used as near-critical-density targets in the laser-driven acceleration of high-energy ions and electrons. Here we report the recent advances in the fabrication technique of such targets. With the further developed floating catalyst chemical vapor deposition (FCCVD) method, large-area ($>25\kern0.5em {\mathrm{cm}}^2$) and highly uniform CNFs are successfully deposited on nanometer-thin metal or plastic foils as double-layer targets. The density and thickness of the CNF can be controlled in the range of $1{-}13\kern0.5em \mathrm{mg}/{\mathrm{cm}}^3$ and $10{-}200\kern0.5em \mu \mathrm{m}$, respectively, by varying the synthesis parameters. The dependence of the target properties on the synthesis parameters and the details of the target characterization methods are presented for the first time.

This paper is about the construction of a unified gas-kinetic scheme (UGKS) for a coupled system of radiative transport and material heat conduction with different diffusive limits. Different from the previous approach, instead of including absorption/emission only, the current method takes both scattering and absorption/emission mechanism into account in the radiative transport process. As a result, two asymptotic limiting solutions will appear in the diffusive regime. In the strong absorption/emission case, an equilibrium diffusion limit is obtained, where the system is mainly driven by a nonlinear diffusion equation for the equilibrium radiation and material temperature. However, in the strong scattering case, a non-equilibrium limit can be obtained, where coupled nonlinear diffusion system with different radiation and material temperature is obtained. In addition to including the scattering term in the transport equation, an implicit UGKS (IUGKS) will be developed in this paper as well. In the IUGKS, the numerical flux for the radiation intensity is constructed implicitly. Therefore, the conventional CFL constraint for the time step is released. With the use of a large time step for the radiative transport, it becomes possible to couple the IUGKS with the gas dynamic equations to develop an efficient numerical method for radiative hydrodynamics. The IUGKS is a valid method for all radiative transfer regimes. A few numerical examples will be presented to validate the current implicit method for both optical thin to optical thick cases.

Biological hydrogel is important in drug delivery system and tissue engineering. In this paper, we prepared a series of biological hydrogels with N,O-carboxymethyl chitosan (CS) and oxidized safflower and ligusticum wallichii polysaccharide-II (oxidized SLWP-II). Morphological analysis indicated the N,O-carboxymethyl CS/oxidized SLWP-II hydrogels (CSLHs) had porous interior structures, pore diameter ranged from tens to hundreds of micrometers. In vitro release test showed, with proportion of N,O-carboxymethyl CS to oxidized SLWP increasing from 1:1 to 1:3, cumulative release of bovine serum albumin decreased from 99 to 82%. In vitro cytotoxicity study showed that the developed hydrogels were not cytotoxic during one week of culturing with WI-38 cells, and they have a role in promoting cell proliferation. So the N,O-carboxymethyl CS/oxidized safflower and ligusticum wallichii polysaccharide-II hydrogels might have potential application in the drug delivery system and tissue engineering.

Hydroxytyrosol (HT) is a major polyphenolic compound found in olive oil with reported anti-cancer and anti-inflammatory activities. However, the neuroprotective effect of HT on type 2 diabetes remains unknown. In the present study, db/db mice and SH-SY-5Y neuroblastoma cells were used to evaluate the neuroprotective effects of HT. After 8 weeks of HT administration at doses of 10 and 50 mg/kg, expression levels of the mitochondrial respiratory chain complexes I/II/IV and the activity of complex I were significantly elevated in the brain of db/db mice. Likewise, targets of the antioxidative transcription factor nuclear factor erythroid 2 related factor 2 including p62 (sequestosome-1), haeme oxygenase 1 (HO-1), and superoxide dismutases 1 and 2 increased, and protein oxidation significantly decreased. HT treatment was also found to activate AMP-activated protein kinase (AMPK), sirtuin 1 and PPARγ coactivator-1α, which constitute an energy-sensing protein network known to regulate mitochondrial function and oxidative stress responses. Meanwhile, neuronal survival indicated by neuron marker expression levels including activity-regulated cytoskeleton-associated protein, N-methyl-d-aspartate receptor and nerve growth factor was significantly improved by HT administration. Additionally, in a high glucose-induced neuronal cell damage model, HT effectively increased mitochondrial complex IV and HO-1 expression through activating AMPK pathway, followed by the prevention of high glucose-induced production of reactive oxygen species and declines of cell viability and VO2 capacity. Our observations suggest that HT improves mitochondrial function and reduces oxidative stress potentially through activation of the AMPK pathway in the brain of db/db mice.

Objective: The incidence, types, and influencing factors of injuries due to snow-ice disasters are essential for public health preparedness. This study was designed to assess such factors of injuries during the 22-day snowstorm in Ningbo, Zhejiang Province, China, in 2008.

Methods: A multistage cluster probability sampling method was applied to select the study population in urban, rural, and mountainous areas. Data including sociodemographic characteristics, frequency, and types of injuries during the snowstorm between January 20 and February 10, 2008, were obtained by face-to-face interviews using a structured questionnaire and by checking the participants' medical records. Univariate and multivariate regression analyses were used to determine the factors significantly associated with the risk of injuries.

Results: A total of 3169 residents of 1416 families took part in this survey. In 581 residents, 602 injuries were identified. Incidences of frostbite, falling injury, and traffic accident–related injury were 12.78%, 5.30%, and 0.50%, respectively. Injury occurred more frequently in women than in men (odds ratio [OR], 1.42; 95% CI, 1.19-1.70). Frostbite occurred more frequently in women than in men (adjusted OR, 1.86; 95% CI, 1.43-2.41) and more frequently in urban areas than in other areas (adjusted OR, 1.65; 95% CI, 1.24-2.20). Travel by bus or car, wearing a scarf, wearing gloves, wearing a raincoat, reducing outdoor activity, and performing regular physical exercise were independent protective factors of frostbite, with an adjusted OR (95% CI) of 0.35 (0.20-0.61), 0.45 (0.33-0.62), 0.35 (0.26-0.48), 0.45 (0.33-0.61), 0.36 (0.27-0.48), and 0.18 (0.13-0.24), respectively. Falling injury occurred more often in mountainous areas than in other areas (adjusted OR, 1.74; 95% CI, 1.27-2.42). Age 45 years or older, working outside more than 15 days, and wearing a raincoat were independent risk factors of falling injury, with an adjusted OR (95% CI) of 2.30 (1.60-3.32), 1.92 (1.36-2.72), and 2.21 (1.56-3.11), respectively. Falling and traffic accident–related injuries were mainly due to slippery roads.

Conclusions: Frostbite and falling injury were the major injuries caused by an unprecedented snow-ice disaster. Keeping warm and maintaining regular physical exercise appeared to reduce frostbite risk. Public health intervention also reduced the risk of falling and traffic accident–related injuries.

(Disaster Med Public Health Preparedness. 2012;6:363-369)

In this paper, we report the results of a rapid and room temperature integration approach for the selective and structured deposition of carbon nanotubes (CNTs) into three-dimensional microstructures. The approach exploits electrophoretic deposition (EPD) from an aqueous suspension of CNTs, together with suitably patterned and electrically-energized microstructure-bearing substrates. Uniform 2-D and 3-D micropatterns of CNTs on wafer scale have been achieved in less than 4 minutes with controllable thicknesses ranging from 133nm to several micrometers. Orientation of the deposited CNTs was observed in microstructures with certain dimensions. Surface hydrophobicity of the microstructures was found to be critical in achieving well-defined micropatterning of CNTs. A hydrophobic microstructure surface leads to the selective patterning profiles of CNTs, while a hydrophilic surface induces CNTs assembly over the entire microstructure, with resultant loss of selectivity. This approach can be further extended to fabricate 3-D micropatterns with multilayer materials on flexible substrate through the aid of transfer micromolding techniques.

For low-temperature firing of Pb0.94Sr0.06(Ni1/2W1/2)0.02(Mn1/3Nb2/3)0.07(Zr0.51Ti0.49)0.91O3 (PNW–PMN–PZT) system, BiFeO3 is selected as the sintering agent. In this study, the effects of BiFeO3 addition and sintering temperature on the microstructures and piezoelectric properties of the ceramics were investigated in detail. The ceramic with 10 mol% BiFeO3 sintered at 950 °C possesses optimal microstructure and piezoelectric properties. However, with the increase of sintering temperature the lower relative density, abnormal grain growth, and secondary phase accumulated at grain boundaries are observed, which deteriorates the piezoelectric properties. For the ceramics with different BiFeO3 addition sintered at 950 °C, the densification process and the grain growth are improved by suitable BiFeO3, while the morphotropic phase boundary (MPB) moving to the Ti-rich direction and the shrinkage of crystal cell occur. However, extra BiFeO3 inhabits the grain growth and introduces more cavities into the materials. Because of the microstructural changes that accompany the addition of BiFeO3 and the resulting decrease in sintering temperature, the maximum values of the piezoelectric properties are attained. By doping with 10 mol% BiFeO3, the sintering temperature of the PNW–PMN–PZT system can be lowered successfully from 1200 to 950 °C, while the excellent electric properties are kept.