Effects of instantaneous changes in temperature, light, and salinity on the dynamics of dissolved organic carbon release by Sargassum thunbergii.

Although macroalgae are regarded as the emerging fourth category of "blue carbon", few studies are available on the dynamics of dissolved organic carbon (DOC) release. Sargassum thunbergii is a typical intertidal macroalgae; and tidal action usually triggers instantaneous changes in temperature, light and salinity. Therefore, we investigated the mechanism of short-term changes in temperature, light and salinity on DOC release by S. thunbergii. As well as these factors coupled with desiccation, the combined effect of DOC release was revealed. The results showed the DOC release rate of S. thunbergii was from 0.028 to 0.037 mg C g -1(FW) h-1 under different photosynthetically active radiation (PAR, 0-1500 µmol photons m-2 s-1). The DOC release rate of S. thunbergii was from 0.008 to 0.208 mg C g -1(FW) h-1 under different salinity (5-40). The DOC release rate of S. thunbergii was from 0.031 to 0.034 mg C g -1(FW) h-1 under different temperature (10-30 °C). Either the increase in intracellular organic matter concentration due to increased photosynthesis (change in PAR and temperature, active), cell dehydration due to dry-out process (passive) or the decrease in extracellular salt concentration (passive) would lead to an increase in the difference in osmotic pressure and promote DOC release.

Postoperative hypothalamic damage predicts postoperative weight gain in patients with adult-onset craniopharyngioma.

OBJECTIVE: This study aimed to recapitulate the change trajectory of postoperative weight and investigate the association between postoperative hypothalamic damage and weight gain and hypothalamic obesity (HO) in patients with adult-onset craniopharyngioma. METHODS: The data of 96 patients with surgically treated primary adult-onset craniopharyngioma were retrospectively analyzed. The association between postoperative hypothalamic damage based on magnetic resonance images or endoscopic observation and postoperative weight gain and HO was determined by multivariable logistic regression. RESULTS: Forty-seven (49.0%) patients and 18 (18.8%) patients experienced clinically meaningful weight gain (≥5%) and HO at last follow-up, respectively. Postoperative weight significantly increased during the first 6 months following surgery, followed by stabilization. Both grade 2 postoperative hypothalamus damage, as evaluated by the magnetic resonance imaging classification system of Müller et al., and higher scores based on the Roth et al. hypothalamic lesion score were significantly associated with postoperative weight gain of ≥5% (p = 0.005 and p = 0.002) and with HO (p = 0.001 and p = 0.008). Additionally, bilateral hypothalamic injury as evaluated by the Hong et al. hypothalamic injury pattern based on endoscopic observation (p = 0.008) could predict postoperative weight gain ≥5%. CONCLUSIONS: Significant postoperative weight gain is common in patients with adult-onset craniopharyngioma. Postoperative hypothalamic damage can predict clinically meaningful weight gain and HO.