Insulin Secretion and Incretin Hormone Concentration in Women with Previous Gestational Diabetes Mellitus

BackgroundWe examined the change in the levels of incretin hormone and effects of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) on insulin secretion in women with previous gestational diabetes (pGDM).MethodsA 75-g oral glucose tolerance test (OGTT) was conducted on 34 women with pGDM. In addition, 11 women with normal glucose tolerance, matched for age, height and weight, were also tested. The insulin, GIP, GLP-1, and glucagon concentrations were measured, and their anthropometric and biochemical markers were also measured.ResultsAmong 34 women with pGDM, 18 had normal glucose tolerance, 13 had impaired glucose tolerance (IGT) and 1 had diabetes. No significant differences were found in GLP-1 concentration between the pGDM and control group. However, a significantly high level of glucagon was present in the pGDM group at 30 minutes into the OGTT. The GIP concentration was elevated at 30 minutes and 60 minutes in the pGDM group. With the exception of the 30-minute timepoint, women with IGT had significantly high blood glucose from 0 to 120 minutes. However, there was no significant difference in insulin or GLP-1 concentration. The GIP level was significantly high from 0 to 90 minutes in patients diagnosed with IGT.ConclusionGLP-1 secretion does not differ between pGDM patients and normal women. GIP was elevated, but that does not seem to induce in increase in insulin secretion. Therefore, we conclude that other factors such as heredity and environment play important roles in the development of type 2 diabetes

Layer-by-layer assembly for ultrathin energy-harvesting films: Piezoelectric and triboelectric nanocomposite films

Energy-harvesting devices such as piezoelectric and triboelectric nanogenerators (NGs), which can convert mechanical energy into electricity, are under development to be combined with various electronics. In particular, the rapid progress in microscale electronics such as nanorobotics or microelectromechanical devices has strongly increased the demand for ultrathin film devices. Therefore, the thickness, highly uniform structure, chemical composition, interfacial adhesion/interactions, and electrical performance of electrically active films should be carefully considered for high-performance ultrathin energy-harvesting devices. This review focuses on how layer-by-layer (LbL) assembly as a kind of thin film technology can be effectively applied to ultrathin piezoelectric and triboelectric films, and furthermore enhance device performance. First, we introduce the basics of various LbL assemblies using electrostatic, hydrogen-bonding, and covalent-bonding interactions. Then, the LbL-assembly-assisted piezoelectric and triboelectric NGs reported to date are reviewed. Finally, we briefly present perspectives on the direction of LbL assembly for the realization of various ultrathin piezoelectric and triboelectric NGs with high performance. © 2018 The Author(s)1

Effect of Interfacial Adhesion on the Mechanical Properties of Organic/Inorganic Hybrid Nanolaminates

Two different kinds of organic polyelectrolyte (PE)/inorganic silicate nanolaminates carrying dissimilar interfacial adhesion between the organic and the inorganic layers were prepared using the layer-by-layer self-assembly. To investigate the mechanical behavior of the prepared hybrid films, apparent modulus (E'), hardness (H), and crack length were measured by depth-sensing nanoindentation as well as a microVickers experiment. The fracture toughness of the hybrid films was then calculated based on the measured mechanical values. In the case of forming strong interfacial adhesion between the organic and the inorganic layers (A series), the fracture toughness and the crack resistance of hybrid multilayer films were significantly improved as a result of the redistribution of stress concentration and the dissipation of fracture energy by the plasticity of organic PE layers. On the other hand, samples with relatively low interfacial adhesion between the organic and the inorganic layers (T series) had little effect on the improvement of fracture toughness of the hybrid films.This work was financially supported by the National Research Laboratory Program (Grant M1-0104-00-0191) and funded in part by the Ministry of Education through the Brain Korea 21 Programs at Seoul National University. Additionaly, this work was supported by the SRC=ERC program of MOST=KOSEF (R11-2005-048-00000-0). B. Y. also acknowledges the financial support through the Seoul Science Fellowship. The X-ray experiments performed at Pohang Light Source were supported by the Ministry of Science and Technology of Korea (MOST)

Modulating the Pattern Quality of Micropatterned Multilayer Films Prepared by Layer-by-Layer Self-Assembly

Patterned multilayer films composed of poly(allylamine hydrochloride) (PAH) and poly(sodium 4-styrenesulfonate) (PSS) were prepared using dip and spin self-assembly (SA) methods. A silicon substrate was patterned with a photoresist thin film using conventional photolithography, and PAH/PSS multilayers were then deposited onto the substrate surface using dip or spin SA. For spin SA, the photoresist on the substrate was retained, despite the high centrifugal forces involved in depositing the polyelectrolytes (PEs). The patterned multilayer films were formed by immersing the PE-coated substrates in acetone for 10 min. The effect of ionic strength on the pattern quality in dip and spin multilayer patterns (line-edge definition and surface roughness of the patterned region) was investigated by increasing the salt concentration in the PE solution (range 0−1 M). In dip multilayer patterns, the presence of salt increased the film surface roughness and pattern thickness without any deformation of pattern shape. The spin multilayer patterns formed without salt induced a height profile of about 130 nm at the pattern edge, whereas the patterns formed with high salt content (1 M) were extensively washed off the substrates. Well-defined pattern shapes of spin SA multilayers were obtained at an ionic strength of 0.4 M NaCl. Multilayer patterns prepared using spin SA and lift-off methods at the same ionic strength had a surface roughness of about 2 nm, and those prepared using the dip SA and lift-off method had a surface roughness of about 5 nm. The same process was used to prepare well-defined patterns of organic/metallic multilayer films consisting of PE and gold nanoparticles. The spin SA process yielded patterned multilayer films with various lengths and shapes.This work was supported by the Ministry of Education through the Brain Korea 21 Program at Seoul National University, funded in part by the National Research Laboratory Program (Grant M1-0104-00-0191), and the Australian Research Council (Discovery Project and Federation Fellowship schemes)

Conceptual Development Process of Mass-customizable Data Analytics Services for Manufacturing SMEs

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Charge-Transfer Effects of Organic Ligands on Energy Storage Performance of Oxide Nanoparticle-Based Electrodes

One of the most difficult challenges related to pseudocapacitive nanoparticle (PC NP)-based energy storage electrodes with theoretically high capacity is to overcome the sluggish charge-transfer kinetics that result from the poorly conductive PC NPs and bulky/insulating organics (i.e., organic ligands and/or polymeric binders) within the electrodes. Herein, it is reported that physical/chemical functionalities of organic ligands and their molecular-scale coating onto NPs have considerable effects on the rate capability and capacity of oxide NP-based pseudocapacitor electrodes. For this study, pseudocapacitive iron oxide (Fe3O4) NPs are layer-by-layer (LbL)-assembled with conductive indium tin oxide (ITO) NPs using various types of organic ligands (or linkers). In particular, hydrazine ligands, which have extremely small molecular size and strong chemical reducing properties, can effectively remove bulky organic ligands from the NP surface, and thus reduce the separation distance between neighboring NPs. Simultaneously, the hydrazine ligands significantly increase the number of oxygen vacancies on Fe3O4 and ITO NPs during LbL deposition, which markedly enhances the rate capability and capacitance of the electrodes compared to other organic ligands with bulky size and/or without reducing properties. This approach can provide a fundamental basis for developing and designing various high-performance electrochemical electrodes based on metal oxide NPs. © 2021 Wiley-VCH GmbH1

Feasibility research on development of product-independent assembly complexity model

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Textile-Type Lithium-Ion Battery Cathode Enabling High Specific/Areal Capacities and High Rate Capability through Ligand Replacement Reaction-Mediated Assembly

Achieving high energy storage performance and fast rate capability at the same time is one of the most critical challenges in battery technology. Here, a high-performance textile cathode with notable specific/areal capacities and high rate capability through an interfacial interaction-mediated assembly that can directly bridge all interfaces existing between textile and conductive materials and between conductive and active materials, minimizing unnecessary insulating organics is reported. First, amine (NH2)- and carboxylic acid (COOH)-functionalized multiwalled carbon nanotubes (MWNTs) are alternately layer-by-layer (LbL)-assembled onto cellulose textiles for the preparation of conductive textiles using hydrogen bonding interactions. Dioleamide-stabilized LiFePO4 nanoparticles (DA-LFP NPs) with high crystallinity and high dispersion stability in organic media are consecutively LbL-assembled with MWNT-NH2 onto conductive textiles through ligand replacement between native DA ligands bound to the surface of the LFP NPs and NH2 groups of MWNTs. In this case, 35 nm sized LFP NPs are densely and uniformly adsorbed onto all regions of the textile, and additionally, their areal capacities are increased according to the deposition number without a significant loss of charge transfer kinetics. The formed textile cathodes exhibit remarkable specific/areal capacities (196 mAh g(-1)/8.3 mAh cm(-2) at 0.1 C) and high rate capability with highly flexible mechanical properties.1