Origin traceability of Cordyceps sinensis based on trace elements and stable isotope fingerprints.

Cordyceps sinensis is a kind of valuable Chinese herbal medicine, and its quality and price depend on the place of origin. Building a traceability system for Cordyceps sinensis products is an effective way to protect Cordyceps sinensis geographical indication products and consumers. In this study, concentrations of 45 trace elements and stable C, N, and Pb isotopes were used to distinguish Cordyceps sinensis samples from different habitats and different varieties (natural and artificial). The results showed that there were significant differences in the isotope compositions of N and Pb and trace elements contents in the Cordyceps sinensis samples from different sources. Stepwise discriminant analysis was used to select effective traceability indicators, and three discriminant models were successfully established. A combination of Co, Sr, Cu, Tl, and Zr indexes was selected to distinguish the naturally grown samples from the artificially cultivated ones, with an overall cross-validation correctness rate of 90.0 %; while a combination of As, Cu, Rb, Tl, W, and Zr indexes was adopted to distinguish the naturally grown samples from different regions, with a corresponding 100.0 % overall cross-validation correctness rate. To simultaneously distinguish samples between natural and artificial and between different regions, a combination of As, Cu, Rb, Tl, U, W, and δ15N indexes was employed, with an overall cross-validation correctness rate of 89.3 %.

Phosphorus Doping Strategy-Induced Synergistic Modification of Interlayer Structure and Chemical State in Ti3C2Tx toward Enhancing Capacitance.

Heteroatom doping is considered an effective method to substantially improve the electrochemical performance of Ti3C2Tx MXene for supercapacitors. Herein, a facile and controllable strategy, which combines heat treatment with phosphorous (P) doping by using sodium phosphinate (NaH2PO2) as a phosphorus source, is used to modify Ti3C2Tx. The intercalated ions from NaH2PO2 act as "pillars" to expand the interlayer space of MXene, which is conducive to electrolyte ion diffusion. On the other hand, P doping tailors the surface electronic state of MXene, optimizing electronic conductivity and reducing the free energy of H+ diffusion on the MXene surface. Meanwhile, P sites with lower electronegativity owning good electron donor characteristics are easy to share electrons with H+, which is beneficial to charge storage. Moreover, the adopted heat treatment replaces -F terminations with O-containing groups, which enhances the hydrophilicity and provides sufficient active sites. The change in surface functional groups increases the content of high valence-stated Ti with a high electrochemical activity that can accommodate more electrons during discharge. Synergistic modification of interlayer structure and chemical state improves the possibility of Ti3C2Tx for accommodating more H+ ions. Consequently, the modified electrode delivers a specific capacitance of 510 F g-1 at 2 mV s-1, and a capacitance retention of 90.2% at 20 A g-1 after 10,000 cycles. The work provides a coordinated strategy for the rational design of high-capacitance Ti3C2Tx MXene electrodes.

Balancing conflicting mitigation and adaptation behaviours of urban residents under climate change and the urban heat island effect.

Under a warming climate and urban heat island effects, cooling behaviours are increasingly important for city dwellers. Cooling actions, especially air conditioning, receive increasing scrutiny in social science, as does engagement and communication on behaviours spanning adaptation and mitigation. In response, this paper evaluates the relation between residents' adaptation and mitigation behaviours around cooling in Fukuoka, Japan, and draws lessons for communication on encouraging adaptation and mitigation actions. A survey distributed to residents in six areas of Fukuoka, Japan, assessed perceptions of global warming and urban heat island effects, frequency of mitigation and adaptation behaviours, use of air conditioning, electricity bills and evaluation of green spaces. We observe a difference between respondents using air conditioning with an energy-saving (i.e. mitigation) focus, versus those using air conditioning with an adaptation (i.e. cooling) focus. We also note residents emphasising mitigation behaviours may use shade in parks or cooling centres as alternative cooling strategies, but that awareness of effective air conditioning use may be lacking. Our findings build on existing literature by reinforcing - in a subtropical context - the need to reconsider practices around air conditioner use; and illustrate the value of a breadth of messages to promote joint mitigation and adaptation actions.