Little things matter Particulate air pollution 2.5 micrometers or smaller in size (PM2.5) is a major cause of human mortality, and controlling its production is a health policy priority. Nitrogen oxides are an important precursor of PM2.5 and have been a focus of pollution control programs. However, Gu et al . now show that abating ammonia emissions is also an important component of PM2.5 reduction, and the societal benefits of abatement greatly outweigh the costs (see the Perspective by Erisman). Reducing ammonia emissions thus would be a cost-effective complement to nitrogen oxides and sulfur dioxide controls. —HJS

Urbanization has often been considered a threat to food security since it is likely to reduce the availability of croplands. Using spatial statistics and scenario analysis, we show that an increase in China's urbanization level from 56% in 2015 to 80% in 2050 would actually release 5.8 million hectares of rural land for agricultural production-equivalent to 4.1% of China's total cropland area in 2015. Even considering the relatively lower land fertility of these new croplands, crop production in 2050 would still be 3.1-4.2% higher than in 2015. In addition, cropland fragmentation could be reduced with rural land release and a decrease in rural population, benefiting large-scale farming and environmental protection. To ensure this, it is necessary to adopt an integrated urban-rural development model, with reclamation of lands previously used as residential lots. These insights into the urbanization and food security debate have important policy implications for global regions undergoing rapid urbanization.

Cropland is a main source of global nitrogen pollution1,2. Mitigating nitrogen pollution from global croplands is a grand challenge because of the nature of non-point-source pollution from millions of farms and the constraints to implementing pollution-reduction measures, such as lack of financial resources and limited nitrogen-management knowledge of farmers3. Here we synthesize 1,521 field observations worldwide and identify 11 key measures that can reduce nitrogen losses from croplands to air and water by 30–70%, while increasing crop yield and nitrogen use efficiency (NUE) by 10–30% and 10–80%, respectively. Overall, adoption of this package of measures on global croplands would allow the production of 17 ± 3 Tg (1012 g) more crop nitrogen (20% increase) with 22 ± 4 Tg less nitrogen fertilizer used (21% reduction) and 26 ± 5 Tg less nitrogen pollution (32% reduction) to the environment for the considered base year of 2015. These changes could gain a global societal benefit of 476 ± 123 billion US dollars (USD) for food supply, human health, ecosystems and climate, with net mitigation costs of only 19 ± 5 billion USD, of which 15 ± 4 billion USD fertilizer saving offsets 44% of the gross mitigation cost. To mitigate nitrogen pollution from croplands in the future, innovative policies such as a nitrogen credit system (NCS) could be implemented to select, incentivize and, where necessary, subsidize the adoption of these measures.

China's agricultural sector is dominated by smallholder farms, which exhibit relatively low nutrient use efficiency, low agricultural income and substantial nonpoint source pollution. Here, by integrating data from over 40,000 rural surveys, ecological modelling, and geostatistical analysis, we found that 86% of Chinese croplands could be consolidated to establish a large-scale farming regime with an average field size greater than 16 hectares. This would result in a 42% reduction of total nitrogen input, an 18% increase of nitrogen use efficiency, and a 55% reduction in labor requirement, while doubling labor income. Despite requiring a one-time investment of approximate 370 billion US dollars for land consolidation, agricultural profits overall would double due to agricultural production costs being halved. It is spatially feasible and cost-effective to consolidate small land patches for transformation of smallholder to large-scale farming that makes a substantial contribution to attaining sustainable agricultural development in

Background: Oncolytic viruses (OVs) are emerging as potent inducers of immunogenic cell death (ICD), releasing danger-associated molecular patterns (DAMPs) that induce potent anticancer immunity. Oncolytic Newcastle disease virus (NDV) has been shown to educe ICD in both glioma and lung cancer cells. The objective of this study is to investigate whether oncolytic NDV induces ICD in melanoma cells and how it is regulated. Methods: Various time points were actuated to check the expression and release of ICD markers induced by NDV strain, NDV/FMW in melanoma cell lines. The expression and release of ICD markers induced by oncolytic NDV strain, NDV/FMW, in melanoma cell lines at various time points were determined. Surface-exposed calreticulin (CRT) was inspected by confocal imaging. The supernatants of NDV/FMW infected cells were collected and concentrated for the determination of ATP secretion by ELISA, HMGB1, and HSP70/90 expression by immunoblot (IB) analysis. Pharmacological inhibition of apoptosis, autophagy, necroptosis, ER Stress, and STAT3 (signal transducer and activator of transcription 3) was achieved by treatment with small molecule inhibitors. Melanoma cell lines stably depleted of STAT3 were established with lentiviral constructs. Supernatants from NDV-infected cells were intratumorally injected to mice bearing melanoma cells-derived tumors. Results: Oncolytic NDV induced CRT exposure, the release of HMGB1 and HSP70/90 as well as secretion of ATP in melanoma cells. Inhibition of apoptosis, autophagy, necroptosis or ER stress attenuated NDV/FMW-induced release of HMGB1 and HSP70/90. Moreover, NDV/FMW-induced ICD markers in melanoma cells were also suppressed by either treatment with a STAT3 inhibitor or shRNA-mediated depletion of STAT3. Of translational importance, treatment of mice bearing melanoma cells-derived tumors with supernatants from NDV/FMW-infected cells significantly inhibited tumor growth. Conclusions: Our data authenticate that oncolytic NDV/FMW might be a potent inducer of ICD in melanoma cells, which is amalgamated with several forms of cell death. We also show that STAT3 plays a role in NDV/FMW-induced ICD in melanoma cells. Together, our data highlight oncolytic NDV as propitious for cancer therapeutics by stimulatingan anti-melanoma immune response.