Minimal important changes in standard deviation units are highly variable and no universally applicable value can be determined

[Objectives] This study aims to describe the distribution of anchor-based minimal important change (MIC) estimates in standard deviation (SD) units and examine if the robustness of such estimates depends on the specific SD used or on the methodological credibility of the anchor-based estimates. [Design and Setting] We included all anchor-based MIC estimates from studies published in MEDLINE and relevant literature databases upto October 2018. Each MIC was converted to SD units using baseline, endpoint, and change from baseline SDs. We performed a descriptive analysis of MICs in SD units and checked how the distribution would change if MICs with low methodological credibility were excluded from the analysis. [Results] We included 1, 009 MIC estimates from 182 studies. The medians and interquartile ranges of MICs in SD units were 0.43 (0.25 to 0.69), 0.42 (0.22 to 0.70), and 0.51 (0.28 to 0.78) for baseline, endpoint, and change SD units, respectively. Some MICs were extremely large or small. The distribution did not change significantly after excluding MICs estimated by less credible methods. [Conclusions] The size of the universally applicable MIC in SD units could not be determined. Anchor-based MICs in SD units were widely distributed, with more than half in the range of 0.2 to 0.8

Localization and trafficking of aquaporin 2 in the kidney

Aquaporins (AQPs) are membrane proteins serving in the transfer of water and small solutes across cellular membranes. AQPs play a variety of roles in the body such as urine formation, prevention from dehydration in covering epithelia, water handling in the blood–brain barrier, secretion, conditioning of the sensory system, cell motility and metastasis, formation of cell junctions, and fat metabolism. The kidney plays a central role in water homeostasis in the body. At least seven isoforms, namely AQP1, AQP2, AQP3, AQP4, AQP6, AQP7, and AQP11, are expressed. Among them, AQP2, the anti-diuretic hormone (ADH)-regulated water channel, plays a critical role in water reabsorption. AQP2 is expressed in principal cells of connecting tubules and collecting ducts, where it is stored in Rab11-positive storage vesicles in the basal state. Upon ADH stimulation, AQP2 is translocated to the apical plasma membrane, where it serves in the influx of water. The translocation process is regulated through the phosphorylation of AQP2 by protein kinase A. As soon as the stimulation is terminated, AQP2 is retrieved to early endosomes, and then transferred back to the Rab 11-positive storage compartment. Some AQP2 is secreted via multivesicular bodies into the urine as exosomes. Actin plays an important role in the intracellular trafficking of AQP2. Recent findings have shed light on the molecular basis that controls the trafficking of AQP2

Fracture Strength Evaluation of Agglomerates of Fatty Acid-Coated CaCO3 Nanoparticles by Nano-Indentation

Nanoparticles often form agglomerates during their manufacturing process. When nanoparticles form agglomerates, their inherent properties cannot be fully exploited. In this study, we attempted to establish a conventional method to evaluate the fracture strength of agglomerates into smaller parts. We used a commercially available nano-indentation instrument with a flat indenter tip. We chose calcium carbonate nanoparticles with stearic acid coatings as model materials. It was found that the more fatty acid that is coated on the particle surface, the stronger the agglomerates become. The technique we propose in this study can be used to rapidly evaluate the fracture strength of nanoparticle agglomerates

Fabrication of Single-Crystalline Calcite Needle-Like Particles Using the Aragonite–Calcite Phase Transition

Calcium carbonate (CaCO3) occurs in two major polymorphs: rhombohedral calcite and orthorhombic aragonite, the latter is thermodynamically metastable. In this study, we first prepared aragonite needle-like particles by introducing CO2-containing gas into Ca(OH)2 aqueous slurry. Then, the resulted aragonite particles were heat treated at 500 °C for 1 h, in order to induce the aragonite–calcite phase transition. Particle structures before and after the heat treatment were characterized mainly by powder X-ray diffractometry (XRD), field emission-scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). We found that single-crystalline calcite needle-like particles with zigzag surface structures can be fabricated using the phase transition

Evolution of Calcite Nanocrystals through Oriented Attachment and Fragmentation: Multistep Pathway Involving Bottom-Up and Break-Down Stages

A nonclassical multistep pathway involving bottom-up and break-down stages for the evolution of calcite nanograins ∼50 nm in size was demonstrated in a basic aqueous system. Calcite nanofibrils ∼10 nm wide were produced as the initial crystalline phase via amorphous calcium carbonate through ion-by-ion assembly by the carbonation of Ca­(OH)₂ at a high pH of ∼13. Bundles ∼50 nm in diameter were then formed by the subsequent oriented attachment of the nanofibrils. Monodispersed calcite nanograins were finally obtained through spontaneous fragmentation of the fibrous forms via a decrease in pH by further carbonation