Activating Selenium Cathode Chemistry for Aqueous Zinc-Ion Batteries.

Aqueous rechargeable zinc-ion batteries (ARZIBs) are a promising next-generation energy-storage device by virtue of the superior safety and low cost of both the aqueous electrolyte and zinc-metal anode. However, their development is hindered by the lack of suitable cathodes with high volumetric capacity that can provide both lightweight and compact size. Herein, a novel cathode chemistry based on amorphous Se doped with transition metal Ru that mitigates the resistive surface layer produced by the side reactions between the Se cathode and aqueous electrolyte is reported. This improvement can permit high volumetric capacity in this system. Distinct from the conventional conversion mechanisms between Se and ZnSe in Se||Zn cells, this strategy realizes synchronous proton and Zn2+ intercalation/deintercalation in the Ru-doped amorphous Se||Zn half cells. Moreover, an unanticipated Zn2+ deposition/stripping process in this system further contributes to the superior electrochemical performance of this new cathode chemistry. Consequently, the Ru-doped amorphous Se||Zn half cells are found to deliver a record-high capacity of 721 mAh g-1 /3472 mAh cm-3 , and superior cycling stability of over 800 cycles with only 0.015% capacity decay per cycle. This reported work opens the door for new chemistries that can further improve the gravimetric and volumetric capacity of ARZIBs.

A corpus-based study on Chinese and American students' rhetorical moves and stance features in dissertation abstracts.

Dissertation is the most important research genre for graduate students as they step into the academic community. The abstract found at the beginning of the dissertation is an essential part of the dissertation, serving to "sell" the study and impress the readers. Learning to compose a well-organized abstract to promote one's research is therefore an important skill for novice writers when they step into the academic community in their discipline. By comparing 112 dissertation abstracts in material science by Chinese and American doctoral students, this study attempts to analyze not only the rhetorical moves of dissertation abstracts but also the lexical-grammatical features of stance in different abstract moves. The findings show that most of the abstracts include five moves, namely, Situating the research, Presenting the research, Describing the methodology, Summarizing the findings, and Discussing the research. However, fewer abstracts by Chinese students include all five moves. In addition, the choices of stance expressions by the two groups vary across the five abstract moves for different communication purposes. The results of this study have pedagogical implications for facilitating the development of academic writing skills for L2 writers.

Restriction of voltage decay by limiting low-voltage reduction in Li-rich oxide materials.

Li-rich layered oxides are recognized as promising candidates for next-generation Li-ion batteries owing to the high capacity of >250 mAh g-1, but the severe voltage fade has prevented their commercialization. It is widely known that high-voltage charge processes result in layered-to-spinel structural evolution and voltage fade in Li-rich layered oxides. This work emphasizes that limiting the low-voltage reduction can maintain the structure and voltage stability of Li-rich layered oxides after the 4.6 V high-voltage charge processes. A strategy of limiting the low-voltage (<2.8 V) reduction by cycling at 4.6-2.8 V was performed in traditional Li1.2Ni0.13Mn0.54Co0.13O2 and high-Ni Li1.2Ni0.222Mn0.504Co0.074O2. After 300 cycles, traditional Li1.2Ni0.13Mn0.54Co0.13O2 and high-Ni Li1.2Ni0.222Mn0.504Co0.074O2 cycling at 4.6-2 V showed midpoint discharge voltages of 2.83 V and 2.97 V with high voltage fade rates of 2.25 mV/cycle and 2.24 mV/cycle, respectively. While the two materials cycling at 4.6-2.8 V can maintain discharge midpoint voltages of 3.34 V and 3.49 V, with low voltage decay rates of 0.692 mV/cycle and 0.632 mV/cycle, respectively. To better understand the voltage performance, their electric structures were calculated by density functional theory. Physical characterizations were also used to analyze their differences in structural evolution. The results suggested that limiting low-voltage reduction in Li-rich layered oxides is highly necessary for maintaining their structure and voltage stability.

Time-Varying Effects of Marital Status on Gastric Cancer: A Population-Based Study.

BACKGROUND: Although prior studies have shown that marital status affects the prognosis of patients with gastric cancer, its time-varying effects are not well understood. We aimed to investigate the changes in marital status' impact over a 10-year follow-up time among patients with gastric cancer (GC) in the United States. MATERIALS AND METHODS: All patients with gastric cancer diagnosed between 2004 and 2008 in the Surveillance, Epidemiology, and End Results (SEER) database were retrieved. Married patients and unmarried patients (single, separated, divorced or widowed) with complete survival time were selected for comparisons. A total of 14,545 patients who had clinical data and follow-up information available were enrolled. We used Kaplan-Meier analyses and time-dependent flexible parametric models to estimate time-varying hazard ratios (HRs). RESULTS: Unmarried GC patients had worse overall and cancer-specific survival compared with married patients (log-rank test: P < 0.001 and P < 0.001, respectively). The time-varying analysis found that unmarried patients had a significantly higher risk of overall mortality during the 10-year follow-up time, with the lowest adjusted hazard ratio (HR) at 12 months after diagnosis (HR at 12 months, 1.08; 95% CI, 1.03-1.15). For cancer-specific mortality, the time-varying adjusted HR of unmarried patients was significantly higher initially (HR at 12 months, 1.08; 95% CI, 1.02-1.14) but decreased to null after 20 months (HR at 24 months = 1.04; 95% CI = 0.99-1.11). CONCLUSION: Unmarried patients had a higher risk of cancer-specific mortality during the 20 months after gastric cancer diagnosis, which may be an appropriate time frame for intervention.

Plants traditionally used to make Cantonese slow-cooked soup in China.

BACKGROUND: Lǎo huǒ liàng tang (Cantonese slow-cooked soup, CSCS) is popular in Guangdong, China, and is consumed by Cantonese people worldwide as a delicious appetizer. Because CSCS serves as an important part of family healthcare, medicinal plants and plant-derived products are major components of CSCS. However, a collated record of the diverse plant species and an ethnobotanical investigation of CSCS is lacking. Because of globalization along with a renewed interest in botanical and food therapy, CSCS has attracted a growing attention in soup by industries, scientists, and consumers. This study represents the first attempt to document the plant species used for CSCS in Guangdong, China, and the associated ethnomedical function of plants, including their local names, part(s) used, flavors, nature, preparation before cooking, habitats, and conservation status. METHODS: In 2014-2017, participatory approaches, open-ended conversations, and semi-structured interviews were conducted with 63 local people and 48 soup restaurant owners (111 interviews) to better understand the biocultural context of CSCS, emphasizing ethnobotanical uses of plants in Guangdong Province, China. Product samples and voucher specimens were collected for taxonomic identification. Mention Index (QI), frequency of use index (FUI), and economic index (EI) were adopted to evaluate the significance of each plant in the food supply. RESULTS: A total of 97 plant species belonging to 46 families and 90 genera were recorded as having been used in CSCS in the study area. Recorded menus consisted of one or several plant species, with each one used for different purposes. They were classified into 11 functions, with clearing heat being the most common medicinal function. Of the 97 species, 19 grew only in the wild, 8 species were both wild and cultivated, and 70 species were cultivated. Roots and fruits were the most commonly used plant parts in the preparation of CSCS. According to the national evaluation criteria, six of these species are listed on "China's red list" including two endangered, two critically endangered, one near-threatened, and one vulnerable species. The QI, FUI, and EI of the 97 species in the study varied between 0.09 and 1, 0.23 and 9.95, and 0.45 and 6.58, respectively. CONCLUSIONS: As an important part of Cantonese culture, CSCS has been popularized as a local cuisine with a healthcare function. CSCS also reflects the plant species richness and cultural diversity of Guangdong Province. Future research on the safety and efficacy of CSCS as well as on ecological and cultural conservation efforts is needed for the sustainable growth of China's botanical and medicinal plant industry.