Search

Key message: The important anatomical changes in tension wood, e.g., the high fiber ratio and rich mesopores, did not significantly increase the air and nitrogen flow; thus the gas permeability in the longitudinal direction of poplar (Populus deltoidesCL.’55/65′) tension wood is actually affected by the cell tissue macroporous porosity. Context: Gas permeability is one of the most important physical properties of wood and is closely related to its internal microstructure, particularly porosity. Tension wood is widespread in woody plants and displays significant structural differences compared with opposite wood. Aims: The study was designed to clarify the relationship between pore structure and gas permeability in poplar tension wood. Methods: The gas permeability was measured using a self-made device. The meso- and macroporosity characteristics were measured by nitrogen adsorption–desorption and mercury intrusion porosimetry. The flow was simulated using ANSYS Fluent software to illustrate the role of pore structure on permeability. Results: The morphological features of vessels have an effect on wood permeability. Compared with tension wood, opposite wood, which has higher vessel ratio, larger cell lumen diameter, and more rich pits, shows stronger gas permeability. Increasing the airflow path will actually reduce the gas permeability. The simulation results are consistent with the experimental results. Conclusion: In hardwoods, the gas permeability in the longitudinal direction is mainly dictated by the vessels. The high fiber ratio and rich mesopore in tension wood do not significantly increase gas flow, suggesting the permeability of wood was actually determined by the cell tissue with macroporous porosity. Vessel tissue ratio, length and diameter, and intervessel pit size were found responsible for influencing the permeability in the longitudinal direction. [ABSTRACT FROM AUTHOR]

Background: The prevalence of primary aldosteronism concurrent with subclinical Cushing's syndrome was higher than previously thought. Through analyzing a rare clinical case, we summarized the diagnosis and management of primary aldosteronism with subclinical Cushing's syndrome.Case Presentation: A 54-year-old Chinese man of Han nationality was diagnosed as having primary aldosteronism with subclinical Cushing's syndrome. An abdominal computed tomography scan revealed a mass in his left adrenal gland and a mass in his right adrenal gland. After finishing sequential adrenal venous sampling without adrenocorticotropic hormone, the result reminded us that the left and right nodules were responsible for hypercortisolism and aldosterone hypersecretion, respectively. Right and left adrenalectomy were performed successively. The pathological diagnosis was adrenocortical adenoma for both. Histological findings revealed that the right one had positive immunostaining for CYP11B2 and the left one had positive immunostaining for CYP11B1. The immunohistochemistry result helped us to confirm the diagnosis. Somatic KCNJ5 mutation (Leu168Arg) was found in the right tumor; there was no KCNJ5 mutation in the left adrenal tumor.Conclusions: We suggest that patients with primary aldosteronism should have a low-dose overnight dexamethasone suppression test to screen for hypercortisolism. It can help avoid misdiagnoses and contribute to proper understanding of the adrenal vein sampling result. Making sure of the nidus of aldosterone and cortisol secretion is crucial for the therapy of patients with primary aldosteronism and subclinical Cushing's syndrome. [ABSTRACT FROM AUTHOR]