Observed yield reduction (a) and observed water reduction (b) of various legume species grown in dryland and non-dryland regions.

<p>Observed yield reduction (a) and observed water reduction (b) of various legume species grown in dryland and non-dryland regions.</p

Observed yield reduction (a) and observed water reduction (b) of various legume species grown in tropical and non-tropical regions.

<p>Observed yield reduction (a) and observed water reduction (b) of various legume species grown in tropical and non-tropical regions.</p

Observed yield reduction (a) and observed water reduction (b) of various legume species grown at sites of different soil textures.

<p>Observed yield reduction (a) and observed water reduction (b) of various legume species grown at sites of different soil textures.</p

Relationship between observed yield reduction and observed water reduction of all legume species (a), common bean (b), soybean (c), and groundnut (d).

<p>Relationship between observed yield reduction and observed water reduction of all legume species (a), common bean (b), soybean (c), and groundnut (d).</p

Distribution of the locations of all the studies used in this synthesis.

<p>The map was generated using ArcGIS 10.0 (ESRI, Redlands, CA).</p

World production and top producers of different cereal crops [3].

<p>World production and top producers of different cereal crops [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0156362#pone.0156362.ref003" target="_blank">3</a>].</p

Flowchart diagram of the process of obtaining literature data to build a database for this study.

<p>Flowchart diagram of the process of obtaining literature data to build a database for this study.</p

The name, origin or center of diversity [21], world production and top world producer of different types of pulses, soybean and groundnut.

<p>The data are from Food and Agricultural Organization [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127401#pone.0127401.ref008" target="_blank">8</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127401#pone.0127401.ref009" target="_blank">9</a>].</p><p>*should only include <i>Phaseolus</i> spp., but some <i>Vigna</i> spp. are also included since in the past they were classified as <i>Phaseolus</i>.</p><p>**number in brackets is the percentage of total legume production.</p><p>The name, origin or center of diversity [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127401#pone.0127401.ref021" target="_blank">21</a>], world production and top world producer of different types of pulses, soybean and groundnut.</p

Observed yield reduction (a) and observed water reduction (b) of various legume species.

<p>Observed yield reduction (a) and observed water reduction (b) of various legume species.</p

Toward a Comprehensive Understanding of the Anomalously Small Contact Angle of Surface Nanobubbles

Experimental studies have demonstrated that the gas phase contact angle (CA) of a surface nanobubble (SNB) is much smaller than that of a macroscopic gas bubble. This reduced CA plays a crucial role in prolonging the lifetime of SNBs by lowering the bubble pressure and preventing gas molecules from dissolving in the surrounding liquids. Despite extensive efforts to explain the anomalously small CA, a consensus about the underlying reasons is yet to be reached. In this study, we conducted experimental investigations to explore the influence of gas molecules adsorbed at the solid–liquid interface on the CA of SNBs created through the solvent exchange (SE) method and temperature difference (TD). Interestingly, no significant change is observed in the CA of SNBs on highly oriented pyrolytic graphite (HOPG) surfaces. Even for nanobubbles on micro/nano pancakes, the CA only exhibited a slight reduction compared to SNBs on bare HOPG surfaces. These findings suggest that gas adsorption at the immersed solid surface may not be the primary factor contributing to the small CA of the SNBs. Furthermore, the CA of SNBs formed on polystyrene (PS) and octadecyltrichlorosilane (OTS) substrates was also investigated, and a considerable increase in CA was observed. In addition, the effects of other factors including impurity, electric double layer (EDL) line tension, and pinning force upon the CA of SNBs were discussed, and a comprehensive model about multiple factors affecting the CA of SNBs was proposed, which is helpful for understanding the abnormally small CA and the stability of SNBs