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Purpose: Identify and examine the associations between health behaviors and increased risk of adolescent suicide attempts, while controlling for socio-economic and demographic differences. Design: A data-driven analysis using cross-sectional data. Setting: Communities in the state of Montana from 1999 to 2017. Selected Montana as it persistently ranks among the top 3 vulnerable states in the U.S. over the past years. Subjects: Selected 22,447 adolescents of whom 1,631 adolescents attempted suicide at least once. Measures: Overall 29 variables (predictors) accounting for psychological behaviors, illegal substances consumption, daily activities at schools and demographic backgrounds were considered. Analysis: A library of machine learning algorithms along with the traditionally-used logistic regression were used to model and predict suicide attempt risk. Model performances—goodness-of-fit and predictive accuracy—were measured using accuracy, precision, recall and F-score metrics. Additionally, χ2 analysis was used to evaluate the statistical significance of each variable. Results: The non-parametric Bayesian tree ensemble model outperformed all other models, with 80.0% accuracy in goodness-of-fit (F-score: 0.802) and 78.2% in predictive accuracy (F-score: 0.785). Key health-behaviors identified include: being sad/hopeless (p < 0.0001), followed by safety concerns at school (p < 0.0001), physical fighting (p < 0.0001), inhalant usage (p < 0.0001), illegal drugs consumption at school (p < 0.0001), current cigarette usage (p < 0.0001), and having first sex at an early age (below 15 years of age). Additionally, the minority groups (American Indian/Alaska Natives, Hispanics/Latinos) (p < 0.0001), and females (p < 0.0001) are also found to be highly vulnerable to attempting suicides. Conclusion: Significant contribution of this work is understanding the key health-behaviors and health disparities that lead to higher frequency of suicide attempts among adolescents, while accounting for the non-linearity and complex interactions among the outcome and the exposure variables. Findings provide insights on key health-behaviors that can be viewed as early warning signs/precursors of suicide attempts among adolescents. [ABSTRACT FROM AUTHOR]

Peroxidase mimics of nanoscale materials as alternatives to natural peroxidases have found widespread uses in biomedicine. Among various types of peroxidase mimics, platinum-group metal (PGM) nanocrystals have drawn considerable attention in recent years due to their superior properties. Particularly, PGM nanocrystals display high catalytic efficiencies, allow for facile surface modifications, and possess excellent stabilities. This feature article summarizes our recent work on development of PGM nanocrystals as peroxidase mimics and exploration of their applications in in vitro diagnostics. We begin with a brief introduction to controlled synthesis of PGM nanocrystals in solution phase. We then elaborate on a variety of physicochemical parameters that can be carefully tuned to optimize the peroxidase-like properties of PGM nanocrystals. Then, we highlight the applications of PGM nanocrystals in different in vitro diagnostic platforms. We conclude this article with personal perspectives on future research directions in this emerging field, where challenges and opportunities are remarked. [ABSTRACT FROM AUTHOR]

Integrating phase change material with building envelopes is an effective way to reduce cooling or heating loads, improve indoor thermal comfort and save building energy consumption. In this paper, the composite phase change material of sodium acetate and urea is prepared and its thermal–physical properties with different mixing mass ratios are investigated through experiment and T-history method. Moreover, the heat transfer model of building envelopes with phase change material is established and different phase change material locations in external walls for thermal insulation are compared based on integrated uncomfortable degree. The results show that (1) with rising urea mass fraction, both phase change temperature and latent fusion heat (enthalpy) decline; (2) strontium sulfate is an effective nucleating additive to decrease super-cooling degree for such phase change material solidification and (3) to improve indoor thermal comfort, it is preferable to put phase change material in the middle of external walls. Furthermore, the illustrative example of an office building in Chengdu indicates that phase change material insulation can lead to time lag and decrement for indoor air temperature variations. It also indicates that after inserting such phase change material into building external wall, the highest indoor temperature can be decreased by 7℃, leading to 60% cooling energy saving in one typical summer day. This work can provide guidance for building thermal design with phase change materials.Practical application:The studied sodium acetate–urea composite phase change material has been used as energy storage and thermal insulation materials inserted in envelopes for the demonstration project of low/zero energy consumption passive buildings in China. [ABSTRACT FROM AUTHOR]

The precise control of electronic throttle plays an important role in improving the power, economy and emission of automobiles. The mathematical model of electronic throttle is established for the accurate tracking control of automotive electronic throttle. Based on the nonlinear characteristics of the electronic throttle, a nonlinear observer is designed to estimate the friction and the reset spring torque in the system, and gives compensation in real-time. The simulation results show that the controller can realize the electronic throttle fast tracking control well. The rise time of the system is about 40 ms, the stable time is about 80 ms, and there is no overshoot. The rise time of the sliding mode controller with the observer is increased by 60%, and the stable time is increased by 47%. At the same time, the observer can quickly track and estimate the nonlinear accurately, and can give more accurate compensation. [ABSTRACT FROM AUTHOR]

Variable refrigerant flow (VRF) air conditioning system is widely used in commercial buildings for space cooling and heating. However, some VRF systems used in high-rise buildings cannot work efficiently or even stop working because of the relatively high ambient air temperature, caused by the thermal plume effect of exhaust heat from outdoor units. In this paper, the thermal plume air flow of the layer-based VRF systems is investigated through computational fluids dynamics (CFD) simulation. Moreover, an illustrative example of practical VRF system in a 30-storey office building in Shenzhen is analyzed to optimize the layout of the outdoor units. Preliminary results show that the exhaust heat of outdoor units can cause ascending thermal plume flow, leading to higher inlet temperatures for VRF air conditioners on upper floors, even exceeding the warning upper threshold value. It also indicates that enlarging the distance between outdoor units on different floors is an effective way to impair the thermal plume effect for VRF outdoor units and improve the thermal performance of the whole system. For the studied case, the average inlet temperatures can be decreased by 22% for VRF outdoor units with floor interval. This work can provide guidance for the optimization layout design of practical VRF air conditioning systems used in high-rise buildings. [ABSTRACT FROM AUTHOR]

Integrating thermal energy storage (TES) with building cogeneration system is an effective way to improve part load efficiency and save primary energy consumption. In this paper, a novel analytical method is put forward to evaluate the energy saving potential of cogeneration system with TES equipment under following thermal load operation strategy. Moreover, the load fluctuation factor is defined, based on the maximal and average load amount, and its relationship with primary energy consumption and system exergy losses are established. The results show that the primary energy consumption is mainly influenced by three factors: (1) no-load fuel consumption ratio and rated efficiency of gas turbine; (2) heating load fluctuation factor; (3) ratio of heat to electricity load. Furthermore, with increasing gas turbine efficiency and heating load fluctuation factor, the primary energy saving ratio grows whereas system exergy loss declines. The illustrative example in Beijing indicates that the primary energy consumption decreases by 16% and 23% for the hotel and office building respectively in one typical winter day. This work can provide guidance for practical design cogeneration system with TES equipment. [ABSTRACT FROM AUTHOR]

Rising income segregation perpetuates socioeconomic inequalities, preventing us from developing more sustainable environments. In the literature, little is known about the spatiotemporal dynamics of income segregation under natural disaster. To address this gap, this paper aims to quantify how people experience income segregation in the context of a disaster through their mobility patterns. Specifically, we propose a generalized framework to construct a dynamic mobility network that describes the footprint of residents within their activity spaces, leveraging large-scale mobile phone data. The construction of this network is formulated as a nonlinear programming model and solved by the Lagrangian relaxation and numerical iterative method. A case study is presented to examine income segregation of residents in Harris County (Texas) in access to various critical facilities before, during, and after the winter storm Uri. Our results indicate that income segregation behaviors vary at different critical facilities, as facilities with smaller catchment areas are found to have higher degrees of segregation. We also highlight the disparities in access to critical facilities between low-income and high-income neighborhoods. This paper provides a new venue to better understand income segregation behavior under natural disaster through human mobility networks, which could inform equitable resource allocation in disaster management. • An optimal human mobility network is formulated as a nonlinear programming model. • Income segregation behavior varies at different critical facilities before, during, and after a disaster. • Facilities with smaller catchment areas are found to have higher degrees of segregation. • Mobility patterns in response to a natural disaster are heterogeneous across economic groups. • Significant disparities in access to critical facilities between low-income and high-income neighborhoods are revealed. [ABSTRACT FROM AUTHOR]

Functionalized MoS 2 nanosheets are of significant academic and commercial interest due to their use in electronic and photonic applications as transistors, electrocatalysts, electrodes, and nonlinear optical materials. However, MoS 2 nanosheets exhibit low reactivity and poor dispersibility in common solvents, which significantly hinders their functionalization with optoelectronic groups and their downstream applications. Herein, a porphyrin covalently functionalized MoS 2 nanohybrid (MoS 2 -Por) is synthesized by a mild thiol−ene "click" reaction. Optical studies demonstrate that a dispersion of the MoS 2 -Por nanohybrid in N , N -dimethylformamide (DMF) exhibits reverse saturable absorption (RSA) behavior to femtosecond pulsed laser irradiation at 800 nm, in contrast to the saturable absorption (SA) displayed by MoS 2 nanosheets. This significant switch likely stems from enhanced two-photon absorption (TPA) in the MoS 2 nanosheets, which may be ascribed to efficient charge transfer in the excited-state of the MoS 2 -Por nanohybrid. Polymethyl methacrylate (PMMA) films MoS 2 -Por/PMMA exhibit a low optical limiting threshold of 1.2 mJ cm-2 (18.3 GW cm-2), indicating great potential as an optical limiter. The MoS 2 -Por nanohybrid also exhibits stronger self-focusing than MoS 2 nanosheets towards femtosecond pulses at 800 nm due to the increased free-carries concentration arising from the improved TPA. These observations demonstrate that the MoS 2 -Por nanohybrid is an excellent candidate for optical limiting in the infrared region towards femtosecond pulses, and shed new light on the construction of covalently functionalized MoS 2 nanohybrids for tuning nonlinear optical properties and broadening application scope. • A rational strategy to synthesize the MoS 2 -Por nanohybrid. • The MoS 2 -Por nanohybrid exhibits effective intra-hybrid charge/energy transfer. • Nonlinear absorption at 800 nm is switched by MoS 2 -Por nanohybrid formation. • The MoS 2 -Por/PMMA shows a low optical limiting threshold of 1.2 mJ cm-2. [ABSTRACT FROM AUTHOR]