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Crystal agglomeration is a common phenomenon for most chemicals and pharmaceuticals. The formation of agglomerates usually lowers product purity and generates a broad particle size distribution. This review focuses on preventing agglomeration in solution crystallization, the storage of crystals, and pharmaceutical preparation processes. The agglomeration mechanisms in these stages are analyzed and the effects of operating parameters are summarized. Furthermore, effective control means related to the crystallization environment are elaborated, including solvents, ultrasound, and additives. Special attention is paid to the influence of additives in preventing the aggregation of both suspensions and dried powders. Besides additives used in solution crystallization, the roles of anti-caking agents, stabilizers of nanosuspensions, and excipients of solid dispersions are also discussed. The additive type and properties like hydrophilicity, hydrophobicity, ionic strength, viscosity, the steric hindrance effect, and intermolecular interactions between additives and crystals can greatly affect the degree of agglomeration. [ABSTRACT FROM AUTHOR]

Shadow education is used not only to improve students' educational achievements but also to maintain social reproduction by advantaged families. However, little is known about the socially stratified shadow education participation during COVID-19 when the educational environment was uncertain. Using data collected before and after the COVID-19 outbreak in China, this study finds that parental education was a strong predictor of children's shadow education participation before COVID-19, but this relationship was disrupted during COVID-19. Students of parents of all educational levels equally participated in shadow education during the COVID-19 pandemic. This class-based equity in shadow education was largely explained by the substantive increase in shadow education participation among students of less-educated parents. [ABSTRACT FROM AUTHOR]

AbstractMassive internal migration in China has greatly disadvantaged children who are left behind. This study unravels the mechanism underlying the association between parental migration and children’s mental health through the lenses of social networks and gender. Using data collected in Sichuan, one of the provinces with the largest number of left-behind children in China, this study finds that maternal and paternal migration differ in their associations with left-behind children’s depressive symptoms. While paternal migration is not associated with children’s mental health, maternal migration is found to be significantly correlated with children’s depressive symptoms. Moreover, the negative association is also detected in children with mothers who returned from migration destinations. However, such an association does not vary between sons and daughters. We also find that the negative association between maternal migration and left-behind children’s mental health is partly explained by children’s delinquent social ties. Children who have experienced or are experiencing maternal migration are more likely to make friends who exhibit delinquent behavior. Such friendships are further associated with left-behind children’s vulnerability to depressive symptoms. This demonstration of the intersectionality of social networks and gender contributes to the literature on family, migration, and health. [ABSTRACT FROM AUTHOR]

Motivated by the fast-emerging literature on African immigrants in new destinations, this paper examines the role of religion in the African immigrants' perceived attitudes of Chinese people toward them. Building on the triple-market model, we identify different ways Islam and Christianity influence African immigrants' perceived attitudes in Guangzhou, the most popular gateway city for African immigrants to China. Using both survey and in-depth interview data, we find that Muslim Africans tend to perceive better attitudes of local Chinese toward them than their Christian counterparts. African-dominated congregations, where Christian Africans are used to participating, are negatively associated with African immigrants' perceived attitudes. We argue that the mechanism underlying the relationships reflects how religion influences immigrants' social experiences in China. [ABSTRACT FROM AUTHOR]