Association between hypertensive disorders and Bell's palsy in pregnancy: protocol for a systematic review and meta-analysis.

BACKGROUND: Bell's palsy is an idiopathic peripheral nerve palsy involving the facial nerve. Pregnancy, diabetes mellitus and hypertension are the risk factors for Bell's palsy. However, the association between hypertensive disorders and Bell's palsy during pregnancy or the puerperium remains unclear. This systematic review will comprehensively summarise the literature and evaluate the association between Bell's palsy and hypertensive disorders during pregnancy or the puerperium. METHODS AND ANALYSIS: Systematic searches of PubMed, MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials will be undertaken using prespecified search strategies. Observational studies (cross-sectional studies, cohort studies, case reports and series case reports) written in English that investigate the association between hypertensive disorders of late pregnancy and Bell's palsy during pregnancy or the puerperium will be included. Different authors will independently conduct the eligible study selection, perform data extraction and appraise the quality of included studies. Subgroup analysis will be carried out based on the age of pregnant women (≤35 years old, >35 years old), parity (primipara, multipara) and fetus number (singleton or multiple-gestation pregnancy). ETHICS AND DISSEMINATION: This review will be based on published literature, and thus there is no requirement for ethics approval. The results of this study will aid in the knowledge of the relationship between Bell's palsy during pregnancy or the puerperium and hypertensive disorders of late pregnancy. The results of this systematic review will be shared through publication in a peer-reviewed journal with good visibility for the field of obstetrics and presentations at academic conferences. PROSPERO REGISTRATION NUMBER: CRD42023422902.

Trade-offs between xylem hydraulic efficiency and mechanical strength in Chinese evergreen and deciduous savanna species.

Evergreen and deciduous species coexist in tropical dry forests and savannas, but differ in physiological mechanisms and life-history strategies. Hydraulic conductivity and mechanical support are two major functions of the xylems of woody plant species related to plant growth and survival. In this study, we measured sapwood-specific hydraulic conductivity (Ks), leaf-specific hydraulic conductivity (KL), modulus of rupture (MOR) and elasticity (MOE), xylem anatomical traits and fiber contents in the xylems of 20 woody species with contrasting leaf phenology (evergreen vs deciduous) in a Chinese savanna. Our results showed that deciduous species had significantly higher Ks and KL but lower MOR and MOE than evergreen species. Evergreen species experienced more negative seasonal minimum water potential (Pmin) than deciduous species during the dry season. Furthermore, we found trade-offs between xylem hydraulic efficiency and mechanical strength across species and within the evergreen and deciduous groups, and these trade-offs were modulated by structural and chemical traits. Both Ks and KL were significantly related to hydraulic weighted vessel diameter (Dh) across all species and within the deciduous group. Both MOR and MOE were significantly related to wood density, neutral detergent fiber and acid detergent fiber across species and within evergreen and deciduous groups. Our findings demonstrated that Chinese evergreen and deciduous savanna species diverged in xylem hydraulic and mechanical functions, reflecting conservative and acquisitive life-history strategies for evergreen and deciduous species, respectively. This study provides new information with which to understand the hydraulic and biomechanical properties and ecological strategies of savanna species in long-term dry-hot environments.