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"Zhang, Nan"
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The Needs–Affordances–Features Perspective for the Use of Social Media
The paper develops a needs–affordances–features (NAF) perspective on social media use which posits that individuals’ psychological needs motivate their use of social media applications to the extent to which these applications provide affordances that satisfy these needs. Our theoretical development builds upon two psychological theories, namely self-determination and psychological ownership, to identify five psychological needs (needs for autonomy, relatedness, competence, having a place, and self-identity), that we posit are particularly pertinent to social media use. According to NAF, these psychological needs will motivate use of those social media applications that provide salient affordances to fulfill these needs. We identify such affordances through a comprehensive review of the literature and of social media applications and put forth propositions that map the affordances to the psychological needs that they fulfill. Our theory development generates important implications. First, it has implications for social media research in that it provides an overarching comprehensive framework for the affordances of social media as a whole and the related psychological needs that motivate their use. Future studies can leverage NAF to identify psychological needs motivating the use of specific social media sites based on the affordances the sites provide, and design science research can leverage NAF in the design and bundling of specific social media features to engage users. Second, it has implications for technology acceptance research in that NAF can enrich existing models by opening up the mechanisms through which psychological needs influence user perceptions of social media and their use patterns and behaviors. Finally, NAF provides a new lens and common vocabulary for future studies, which we hope can stimulate cumulative research endeavors to develop a comprehensive framework of information systems affordances in general and the psychological needs that information systems satisfy.
Journal Article
Regulating Fe-spin state by atomically dispersed Mn-N in Fe-N-C catalysts with high oxygen reduction activity
As low-cost electrocatalysts for oxygen reduction reaction applied to fuel cells and metal-air batteries, atomic-dispersed transition metal-nitrogen-carbon materials are emerging, but the genuine mechanism thereof is still arguable. Herein, by rational design and synthesis of dual-metal atomically dispersed Fe,Mn/N-C catalyst as model object, we unravel that the O
2
reduction preferentially takes place on Fe
III
in the FeN
4
/C system with intermediate spin state which possesses one e
g
electron (t
2g
4e
g
1) readily penetrating the antibonding π-orbital of oxygen. Both magnetic measurements and theoretical calculation reveal that the adjacent atomically dispersed Mn-N moieties can effectively activate the Fe
III
sites by both spin-state transition and electronic modulation, rendering the excellent ORR performances of Fe,Mn/N-C in both alkaline and acidic media (halfwave positionals are 0.928 V in 0.1 M KOH, and 0.804 V in 0.1 M HClO
4
), and good durability, which outperforms and has almost the same activity of commercial Pt/C, respectively. In addition, it presents a superior power density of 160.8 mW cm
−2
and long-term durability in reversible zinc–air batteries. The work brings new insight into the oxygen reduction reaction process on the metal-nitrogen-carbon active sites, undoubtedly leading the exploration towards high effective low-cost non-precious catalysts.
The working mechanism of several low-cost electrocatalyst materials is still arguable. Here the authors show a model Fe,Mn/N-C catalyst where the oxygen reduction preferentially takes place on Fe(III) sites with the intermediate spin state (t2g4 eg1) caused by the adjacent Mn-N moieties.
Journal Article
Awakening the dragon : the dragon boat festival
In ancient times, the Chinese saw the dragon as both a protector and a threat, able to bring on rain or cause droughts. To honor this powerful creature, people created long narrow boats that they raced in an annual rainmaking festival. From the wearing of fragrant pouches, to the consumption of rice dumplings, to thrilling boat races, the dragon boat festival of today is a celebration of Chinese traditions all over the world. Arlene Chan, a respected librarian and an experienced dragon boat racer, explores the origins of the festival, it's customs, and the races themselves. Beautifully detailed illustrations by Song Nan Zhang let you experience the beauty and energy of this ancient festival.
Braille
Prevalence of primary open angle glaucoma in the last 20 years: a meta-analysis and systematic review
Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness in the world and is influenced by various sociodemographic factors. This meta-analysis aims to determine the worldwide prevalence of POAG in the adult general population for the last 20 years, and explore variation in prevalence by age, gender and geographical location. An electronic literature search was performed using the PubMed, Embase, and Web of Science databases. Population-based cross-sectional or cohort studies published in the last 20 years (2000–2020) that reported prevalence of POAG were recruited. Relevant studies meeting defined eligibility criteria were selected and reviewed systematically by meta-analysis. The prevalence of POAG was analyzed according to various risk factors. A random effect model was used for the meta-analysis. Fifty publications with a total of 198,259 subjects were included in this meta-analysis. The worldwide overall prevalence of POAG was 2.4% (95% CI 2.0 ~ 2.8%). The prevalence increases with age. Men are found to be more susceptible to POAG than women (RR 1.28, p < 0.01). Africa is found to have the highest prevalence of POAG (4.0%) among all continents. The current estimated global population of POAG is 68.56 million (95% CI 59.99 ~ 79.98). POAG is a worldwide vision threatening disease with high prevalence for the last 20 years. The population-based prevalence of POAG varies widely across individual studies, due to variations in risk factors of age, gender, and population geographic location.
Journal Article
Boosting selective nitrogen reduction to ammonia on electron-deficient copper nanoparticles
Production of ammonia is currently realized by the Haber–Bosch process, while electrochemical N
2
fixation under ambient conditions is recognized as a promising green substitution in the near future. A lack of efficient electrocatalysts remains the primary hurdle for the initiation of potential electrocatalytic synthesis of ammonia. For cheaper metals, such as copper, limited progress has been made to date. In this work, we boost the N
2
reduction reaction catalytic activity of Cu nanoparticles, which originally exhibited negligible N
2
reduction reaction activity, via a local electron depletion effect. The electron-deficient Cu nanoparticles are brought in a Schottky rectifying contact with a polyimide support which retards the hydrogen evolution reaction process in basic electrolytes and facilitates the electrochemical N
2
reduction reaction process under ambient aqueous conditions. This strategy of inducing electron deficiency provides new insight into the rational design of inexpensive N
2
reduction reaction catalysts with high selectivity and activity.
Electrocatalytic nitrogen reduction is promising for ammonia production, but electrocatalysts are limited by low efficiency and high cost. Here, the authors report electron-deficient copper nanoparticles, induced by rectifying contact with polyimide, for selective reduction of nitrogen to ammonia.
Journal Article
The burden and trend of gastric cancer and possible risk factors in five Asian countries from 1990 to 2019
The burdens and trends of gastric cancer are poorly understood, especially in high-prevalence countries. Based on the Global Burden of Disease Study 2019, we analyzed the incidence, death, and possible risk factors of gastric cancer in five Asian countries, in relation to year, age, sex, and sociodemographic index. The annual percentage change was calculated to estimate the trends in age-standardized incidence rate (ASIR) and age-standardized death rate (ASDR). The highest ASIR per 100,000 person-years in 2019 was in Mongolia [44 (95% uncertainty interval (UI), 34 to 55)], while the lowest was in the Democratic People’s Republic of Korea (DPRK) [23 (95% UI, 19 to 29)]. The highest ASDR per 100,000 person-years was in Mongolia [46 (95% UI, 37 to 57)], while the lowest was in Japan [14 (95% UI, 12 to 15)]. Despite the increase in the absolute number of cases and deaths from 1990 to 2019, the ASIRs and ASDRs in all five countries decreased with time and improved sociodemographic index but increased with age. Smoking and a high-sodium diet were two possible risk factors for gastric cancer. In 2019, the proportion of age-standardized disability-adjusted life-years attributable to smoking was highest in Japan [23% (95% UI, 19 to 28%)], and the proportions attributable to a high-sodium diet were highest in China [8.8% (95% UI, 0.21 to 33%)], DPRK, and the Republic of Korea. There are substantial variations in the incidence and death of gastric cancer in the five studied Asian countries. This study may be crucial in helping policymakers to make better decisions and allocate appropriate resources.
Journal Article
Doping Ruthenium into Metal Matrix for Promoted pH‐Universal Hydrogen Evolution
For heterogeneous catalysts, the active sites exposed on the surface have been investigated intensively, yet the effect of the subsurface‐underlying atoms is much less scrutinized. Here, a surface‐engineering strategy to dope Ru into the subsurface/surface of Co matrix is reported, which alters the electronic structure and lattice strain of the catalyst surface. Using hydrogen evolution (HER) as a model reaction, it is found that the subsurface doping Ru can optimize the hydrogen adsorption energy and improve the catalytic performance, with overpotentials of 28 and 45 mV at 10 mA cm−2 in alkaline and acidic media, respectively, and in particular, 28 mV in neutral electrolyte. The experimental results and theoretical calculations indicate that the subsurface/surface doping Ru improves the HER efficiency in terms of both thermodynamics and kinetics. The approach here stands as an effective strategy for catalyst design via subsurface engineering at the atomic level.
Interface modulation via implanting ruthenium in matrix for improved hydrogen evolution performance in alkaline, acidic, and neutral media.
Journal Article
SARS-CoV-2 proteome microarray for global profiling of COVID-19 specific IgG and IgM responses
We still know very little about how the human immune system responds to SARS-CoV-2. Here we construct a SARS-CoV-2 proteome microarray containing 18 out of the 28 predicted proteins and apply it to the characterization of the IgG and IgM antibodies responses in the sera from 29 convalescent patients. We find that all these patients had IgG and IgM antibodies that specifically bind SARS-CoV-2 proteins, particularly the N protein and S1 protein. Besides these proteins, significant antibody responses to ORF9b and NSP5 are also identified. We show that the S1 specific IgG signal positively correlates with age and the level of lactate dehydrogenase (LDH) and negatively correlates with lymphocyte percentage. Overall, this study presents a systemic view of the SARS-CoV-2 specific IgG and IgM responses and provides insights to aid the development of effective diagnostic, therapeutic and vaccination strategies.
Currently very little is known about how our immune system responds to SARS-CoV-2 infection. Here the authors generate a SARS-CoV-2 proteome microarray for profiling of IgG and IgM responses to COVID-19 in patients and find significant responses to ORF9b and NSP5, as well as the S1 and N proteins.
Journal Article