Background

Although amphetamine-type stimulant (ATS) use is an important issue that has caused growing concerns in China as well as other countries, the knowledge of long-term patterns of ATS use in China is limited. This study explored long-term patterns of ATS use in Shanghai, China, and compared the differences by ATS use trajectory groups, seeking to identify risk factors that have implications for the development of targeted intervention programs.

Methods

A total of 377 ATS users were recruited from the Compulsory Isolation Center for Drug Rehabilitation in Shanghai. Group-based trajectory modeling was applied to identify distinctive trajectories of ATS use over 8 years at the time of interviews conducted in 2012. The mean number of days using ATS per month over a year from years 2005 to 2012 was analyzed with a censored normal model.

Results

Three distinctive groups were identified: high-use (19.1%), low-use (66.0%), and increasing-use (14.9%). Relative to the low-use group, the high-use and increasing-use groups were more likely to report having used opiate-type drugs and to have more craving experiences. Psychiatric symptoms following ATS use were frequently reported, with ATS users in the increasing-use and high-use groups more likely to report depression symptoms and suicide behaviors compared to the low-use group. The low-use and increasing-use groups reported more months in drug abuse treatment programs compared to the high-use group.

Conclusions

Addressing ATS use should take into consideration patients' use-related psychiatric symptoms as well as other risk factors, particularly among those with persistent high-level ATS use trajectories.

All solid-state batteries (ASSBs) with ceramic electrolytes and alkali metal anodes are a potential future energy storage technology for vehicle electrification and smart grids. However, uncontrollable dendrite growth toward ultimate short circuiting in solid electrolytes (SEs) has become a serious concern in the design of long-cycle, safe ASSBs, and the underlying mechanism has remained unclear. Here through multiscale imaging and morphodynamic tracking we show that Na dendrites grow in β′′-Al2O3 SEs through an alternating sequence of Na deposition and crack propagation. Atomic-scale imaging evidenced that electrochemical cycling causes massive delamination cracking along the Na+ conduction planes, accompanied by the closure of neighboring conduction channels. In situ SEM observations revealed a dynamic interplay between Na deposition and crack propagation: Na deposition accumulates mechanical stress that induces cracking; cracking releases the local stress, which promotes further Na deposition. Thus, Na deposition and cracking alternatingly proceed until short circuits take place. A multiscale phase-field model is developed to recapitulate the morphodynamics of Na dendrite growth, predicting the tree-like fractal morphology of the growing dendrites. Our findings suggest that decoupling between Na deposition and cracking represents an important route to mitigate uncontrollable dendrite growth in ASSBs.

Layered cathode materials are commonly used in lithium and sodium ion batteries, but they are prone to degradation under electrochemical cycling during battery operation. Here we report a new type of degradation mechanism through the electrochemically induced mechanical buckling and delamination cracking of intercalation layers in a P2 Na0.7-Ni0.3Mn0.6Co0.1O2 (Na-NMC) cathode material. Kinks form in the delaminated layers due to severe local bending, and each kink consists of a vertical array of dislocations, resulting from an easy slip between transition metal oxide layers. In situ mechanical compression experiments directly reveal the kink formation due to strong mechanical anisotropy parallel and perpendicular to the intercalation layers in single-crystal Na-NMC. In situ electrochemical experiments indicate that kinks form during the desodiation process. Our results unveil a new mechanism of electrochemically induced mechanical degradation stemming from weak interlayer bonding in layered cathode materials. This work has broad implications for the mitigation of degradation associated with irreversible interlayer slip in layered cathode materials.