Plastic waste is an emerging environmental issue for our society. Critical action to tackle this problem is to upcycle plastic waste as valuable feedstock. Thermochemical conversion of plastic waste ...has received growing attention. Although thermochemical conversion is promising for handling mixed plastic waste, it typically occurs at high temperatures (300–800 °C). Catalysts can play a critical role in improving the energy efficiency of thermochemical conversion, promoting targeted reactions, and improving product selectivity. This Review aims to summarize the state‐of‐the‐art of catalytic thermochemical conversions of various types of plastic waste. First, general trends and recent development of catalytic thermochemical conversions including pyrolysis, gasification, hydrothermal processes, and chemolysis of plastic waste into fuels, chemicals, and value‐added materials were reviewed. Second, the status quo for the commercial implementation of thermochemical conversion of plastic waste was summarized. Finally, the current challenges and future perspectives of catalytic thermochemical conversion of plastic waste including the design of sustainable and robust catalysts were discussed.
Thermochemical conversion: Plastic waste is one of the most critical issues in recent years. Upcycle plastic waste as valuable feedstock has attracted huge attention. This Review summarizes thermochemical conversion methods that can convert plastic waste into energy, chemicals, and value‐added materials. It also highlights the recent development of catalytic thermochemical conversions and the current challenges of catalytic thermochemical conversion of plastic waste.
Hydrothermal liquefaction (HTL) is a thermochemical conversion technology that shows promising commercial potential for the production of biocrude oil from wet biomass. However, the inevitable ...production of the hydrothermal liquefaction aqueous phase (HTL-AP) acts as a double-edged sword: it is considered a waste stream that without additional treatment clouds the future scale-up prospects of HTL technology; on the other hand, it also offers potential as an untapped nutrient and energy resource that could be valorized. As more researchers turn to liquefaction as a means of producing renewable fuel, there is a growing need to better understand HTL-AP from a variety of vantage points. Specifically, the HTL-AP chemical composition, conversion pathways, energy valorization potential, and the interconnection of HTL-AP conversion with biofuel production technology are particularly worthy of investigation. This paper extensively reviews the impact of HTL conditions and the feedstock composition on the energy and elemental distribution of process outputs with specific emphasis on the HTL-AP. Moreover, this paper also compares and contrasts the current state of value-added products separation along with biological (biomass cultivation, anaerobic fermentation, and bioelectrochemical systems) and thermochemical (gasification and HTL) pathways to valorize HTL-AP. Furthermore, life cycle analysis (LCA) and techno-economic assessments (TEA) are performed to appraise the environmental sustainability and economic implications of these different valorization techniques. Finally, perspectives and challenges are presented and the integration approaches of HTL-AP valorization pathways with HTL and biorefining are explored.
•Novel regularization method based on radial basis function discretization for calculating the DRT.•Improved estimation of DRT only when data collection range is truncated.•MATLAB GUI for computing ...the DRT.
The distribution of relaxation times (DRT) is an approach that can extract time characteristics of an electrochemical system from electrochemical impedance spectroscopy (EIS) measurements. Computing the DRT is difficult because it is an intrinsically ill-posed problem often requiring regularization. In order to improve the estimation of the DRT and to better control its error, a suitable discretization basis for the regularized regression needs to be chosen. However, this aspect has been invariably overlooked in the specialized literature. Pseudo-spectral methods using radial basis functions (RBFs) are, in principle, a better choice in comparison to other discretization basis, such as piecewise linear (PWL) functions, because they may achieve fast convergence. Furthermore, they can yield improved estimation by extending the estimated DRT to the entire frequency spectrum, if the underlying DRT decays to zero sufficiently fast outside the measured frequency range. Additionally, their implementation is relatively easier than other types of pseudo-spectral methods since they do not require ad hoc collocation point distributions. The as-developed novel RBF-based DRT framework was tested against controlled synthetic EIS spectra and real experimental data. Our results indicate that the RBF discretization performance is comparable with that of the PWL discretization at normal data collection range, and with improvement when the EIS acquisition is incomplete. In addition, we also show that applying RBF discretization for deconvolving the DRT problem can lead to faster numerical convergence rate as compared with that of PWL discretization only at error free situation. As a companion to this work we have developed a MATLAB GUI toolbox, which can be used to solve DRT regularization problems.
Mixed lineage kinase domain-like protein （MLKL） was identified to function downstream of receptor interacting protein 3 （RIP3） in tumor necrosis factor-α （TNF）-induced necrosis （also called ...necroptosis）. However, how MLKL functions to mediate necroptosis is unknown. By reconstitution of MLKL function in MLKL-knockout cells, we showed that the N-terminus of MLKL is required for its function in necroptosis. The oligomerization of MLKL in TNF-treated cells is essential for necroptosis, as artificially forcing MLKL together by using the hormone-binding domain （HBD＊） triggers necroptosis. Notably, forcing together the N-terminal domain （ND） but not the C-terminal kinase domain of MLKL causes necroptosis. Further deletion analysis showed that the four-α-helix bundle of MLKL （1-130 amino acids） is sufficient to trigger necroptosis. Both the HBD＊-mediated and TNF-induced complexes of MLKL（ND） or MLKL are tetramers, and translocation of these complexes to lipid rafts of the plasma membrane precedes cell death. The homo-oligomerization is required for MLKL translocation and the signal sequence for plas- ma membrane location is located in the junction of the first and second a-helices of MLKL. The plasma membrane translocation of MLKL or MLKL（ND） leads to sodium influx, and depletion of sodium from the cell culture medium inhibits necroptosis. All of the above phenomena were not seen in apoptosis. Thus, the MLKL oligomerization leads to translocation of MLKL to lipid rafts of plasma membrane, and the plasma membrane MLKL complex acts either by itself or via other proteins to increase the sodium influx, which increases osmotic pressure, eventually leading to membrane rupture.
Gasification is a promising technology for reducing the volume of biowaste feedstock. Further, with the incorporation of steam this thermochemical treatment technology also concomitantly produces H2, ...a high value energy. This paper aims to summarize the status of biowaste gasification technology and detail the benefits and limitations of different gasification processes, especially for biowaste. First, we compare steam with other gasification agents (oxygen and air) to understand the specific effects of gasification agents on the resulting gas quality and quantity. Second, influencing process factors (reactor configurations, temperature, steam to biomass ratio, and catalyst incorporation) are evaluated in terms of their impact on the resulting H2/CO ratio, gas heating value, gas yield, tar yield, and energy recovery. Third, commercial biowaste gasification applications are detailed and the economics and societal impacts are elucidated. Finally, the current challenges facing the field of gasification and the future outlooks of this technology for reducing biowaste are presented.
•Hydrothermal liquefaction (HTL) of microalgae C. pyrenoidosa and S. platensis.•Characterization of bio-crude oils and aqueous fractions during HTL process.•General reaction network for HTL of C. ...pyrenoidosa and S. platensis.•Specific reaction pathways for HTL of lipid, protein and non-fibrous carbohydrate.
Low-lipid microalgae can be successfully converted to bio-crude oil in a hydrothermal liquefaction (HTL) environment. This study examined the behavior of hydrothermal liquefaction of two low-lipid content microalgae in subcritical water between 200°C and 320°C at 20°C intervals. Under these conditions, the chemical composition and functional groups for the bio-crude oil and aqueous fraction were analyzed. Results indicated that reaction temperature greatly affected the distribution of chemical composition and functional groups of HTL bio-crude oil and aqueous fraction. The bio-crude oil with a higher percentage of aliphatic functional groups was obtained at higher reaction temperatures (280–320°C). Besides, the aqueous fraction recovered under the same operating conditions had a lower concentration of nitrogenous organic compounds (NOCs) with two or more methyl groups. The general reaction network for HTL of low-lipid microalgae was proposed. The specific reaction pathways for microalgae substrates were analyzed in terms of lipid, protein and non-fibrous carbohydrate based on the spectral analysis.
The policy enforcing visiting restriction during the COVID-19 pandemic may cause feelings of social isolation among residents in long-term care facilities. This study aimed to explore family members' ...concerns for their relatives during the lockdown period, assess their level of acceptance of the visiting restriction policy and determine the associated factors.
From the 156 family members interviewed, demographic data, satisfaction with overall care quality, worry and concerns for their relatives, acceptance of the visiting restriction and arrangement for the residents if cluster infections occur in the facility were recorded.
Among the members interviewed, 83 (53.2%) were men; mean age of members was 56.3 ± 9.8; most were offspring of residents in the facility (n = 121, 77.6%), most visited the residents at least once a week (n = 113, 72.4%) before the lockdown. The most common concerns of the family members for their relatives were psychological stress (38.5%), followed by nursing care (26.9%) and daily activity (21.1%). Nearly 84.6% of those interviewed accepted the visiting restriction policy, and a higher satisfaction rating independently associated with acceptance of the visiting restriction policy (odds ratio 2.15).
During the lockdown period, staff members should provide more psychological information about residents to their family members. Higher satisfaction rating was found to be independent of the acceptance of the visiting restriction policy. Therefore, good quality of care of the facility wins the trust of family members, and this might mitigate the tension between the family members and staff during a major crisis. Geriatr Gerontol Int ••; ••: ••-•• Geriatr Gerontol Int 2020; 20: 938-942.
Physical activity has benefits on physical and psychological health. The aims of this study were to investigate (1) the relationships between physical activity and life satisfaction and happiness in ...young, middle-aged, and older adults while controlling for demographic characteristics, and (2) the relationships between age and life satisfaction and happiness for different physical activity levels. A total of 2345 healthy adults were recruited. Demographic characteristic, physical activity, life satisfaction, and happiness were collected. Participants were divided into young, middle-aged, and older adult groups based on age, and physical activity was categorized as high, moderate, and low. After controlling for demographic characteristics, participants with high and moderate activity levels had significantly higher life satisfaction and happiness than those with a low activity level across the total population and the three age groups. Age squared was a significant predictor of a positive curvilinear between age and life satisfaction and happiness. Physical activity was significantly related to life satisfaction and happiness in young, middle-aged, and older adults. In addition, life satisfaction and happiness increased with increasing age. The results support the promotion of physical activity.
The Distribution of Relaxation Times (DRT) is an approach of particular interest to the interpretation of Electrochemical Impedance Spectroscopy (EIS) measurements. The DRT allows direct access to ...the time characteristics of the electrochemical system under study. Obtaining the DRT from noisy EIS data requires solving an ill-posed problem using regularization methods. In this work we investigate the optimal choice of the regularization parameter in the case of ridge regression. For this purpose we propose two novel sets of test functions known as real and imaginary discrepancy test function, and real and imaginary cross-validation test functions. Furthermore, we show the validity of these tests with synthetic and real experiments. By applying the optimal regularization parameters, the DRT results from the synthetic experiments (an RC circuit, a ZARC, and a fractal element) successfully reproduce the known exact DRT. Additionally, in the cases taken from electrochemical practice (a collection of RC circuits, a symmetric cell, and a commercial Li-ion battery) our approach confirms the ability to identify various timescales. Additionally, we study the output of the regularization using Least Absolute Shrinkage and Selection Operator (Lasso) and we highlight the added value given by the synergetic use of Lasso and ridge regression.
Necroptosis and pyroptosis are two forms of programmed cell death with a common feature of plasma membrane rupture. Here we studied the morphology and mechanism of pyroptosis in comparison with ...necroptosis. Different from necroptosis, pyroptosis undergoes membrane blebbing and produces apoptotic body-like cell protrusions （termed pyroptotic bodies） prior to plasma membrane rupture. The rupture in necroptosis is explosion-like, whereas in pyroptosis it leads to flattening of cells. It is known that the execution of necroptosis is mediated by mixed lineage kinase domain-like （MLKL） oligomers in the plasma membrane, whereas gasdermin-D （GSDMD） mediates pyroptosis after its cleavage by caspase-1 or caspase-11. We show that N-terminal fragment of GSDMD （GSDMD-N） generated by caspase cleavage also forms oligomer and migrates to the plasma membrane to kill cells. Both MLKL and GSDMD-N are lipophilic and the N-terminal sequences of both proteins are important for their oligomerization and plasma membrane translocation. Unlike MLKL which forms channels on the plasma membrane that induces influx of selected ions which osmotically swell the cells to burst, GSDMD-N forms non-selective pores and does not rely on increased osmolarity to disrupt cells. Our study reveals the pore-forming activity of GSDMD and channel-forming activity of MLKL determine different ways of plasma membrane rupture in pyroptosis and necroptosis.
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