Efficacy and Safety of Aronia, Red Ginseng, Shiitake Mushroom, and Nattokinase Mixture on Insulin Resistance in Prediabetic Adults: A Randomized, Double-Blinded, Placebo-Controlled Trial.

We determined whether oral consumption of Aronia, red ginseng, shiitake mushroom, and nattokinase mixture (3.4: 4.1: 2.4: 0.1 w/w; AGM) improved glucose metabolism and insulin resistance in prediabetic adults in a 12-week randomized, double-blinded clinical trial. Participants with fasting serum glucose concentrations of 100-140 mg/dL were recruited and randomly assigned to an AGM or placebo group. Participants of the AGM group (n = 40) were given an AGM granule containing 4 g of freeze-dried Aronia, red ginseng, shiitake mushroom, and nattokinase (3.4: 4.1: 2.4: 0.1 w/w) twice daily for 12 weeks, and the placebo group participants (n = 40) were provided with corn starch granules identical in appearance, weight, and flavor for 12 weeks. Serum glucose and insulin concentrations were measured during oral-glucose tolerance tests (OGTT) after administering 75 g of glucose in a fasted state. HOMA-IR, liver damage, and inflammation indices were determined, and safety parameters and adverse reactions were assessed. As determined by OGTT, serum glucose concentrations were not significantly different between the AGM and placebo groups after the intervention. However, changes in serum insulin concentrations in the fasted state and Homeostatic model assessment-insulin resistance (HOMA-IR) index after the intervention were significantly lower in the AGM group than in the placebo group (-3.07 ± 7.06 vs. 0.05 ± 6.12, p = 0.043 for serum insulin; -0.85 ± 2.14 vs. 0.07 ± 1.92, p = 0.049 for HOMA-IR). Serum adiponectin concentrations were reduced by intervention in the placebo group but not in the AGM group. Changes in liver damage indexes, including serum activities of the γ-glutamyl transferase, alanine aminotransferase, and aspartate aminotransferase, were lower in the AGM group and significantly reduced in the AGM group more than in the placebo group (p < 0.05). Changes in serum high sensitive-C-reactive protein concentrations in AGM and placebo groups were significantly different (-0.12 ± 0.81 vs. 0.51 ± 1.95, p = 0.06). In conclusion, AGM possibly improves insulin sensitivity and ß-cell function and reduces liver damage and inflammation in prediabetic adults.

Alternating Magnetic Field-Responsive Hybrid Gelatin Microgels for Controlled Drug Release.

Magnetically-responsive nano/micro-engineered biomaterials that enable a tightly controlled, on-demand drug delivery have been developed as new types of smart soft devices for biomedical applications. Although a number of magnetically-responsive drug delivery systems have demonstrated efficacies through either in vitro proof of concept studies or in vivo preclinical applications, their use in clinical settings is still limited by their insufficient biocompatibility or biodegradability. Additionally, many of the existing platforms rely on sophisticated techniques for their fabrications. We recently demonstrated the fabrication of biodegradable, gelatin-based thermo-responsive microgel by physically entrapping poly(N-isopropylacrylamide-co-acrylamide) chains as a minor component within a three-dimensional gelatin network. In this study, we present a facile method to fabricate a biodegradable drug release platform that enables a magneto-thermally triggered drug release. This was achieved by incorporating superparamagnetic iron oxide nanoparticles and thermo-responsive polymers within gelatin-based colloidal microgels, in conjunction with an alternating magnetic field application system.

Biodegradable colloidal microgels with tunable thermosensitive volume phase transitions for controllable drug delivery.

In this study, we present gelatin-based thermoresponsive colloidal microgels that enable the controlled release of drugs by volume phase transition. The microgel was fabricated by physically entrapping poly(N-isopropylacrylamide-co-acrylamide) chains as a minor component within three-dimensional gelatin networks crosslinked by genipin. We demonstrate that our gelatin-based thermoresponsive microgel exhibits a tunable deswelling to temperature increase, which positively correlated to the release of bovine serum albumin (BSA) as a function of poly(N-isopropylacrylamide-co-acrylamide) concentration. The microgel was enzymatically degradable by collagenase treatment. The extent of BSA release and biodegradability were tuned by controlling the crosslinking degree of the gelatin matrix. Meeting a great need for design and synthesis of auto-degenerating smart microgels that enable the controlled release of therapeutic proteins in responsive to external stimuli, our gelatin-based microgels that satisfy both thermoresponsivity and biodegradability have a great potential in tissue engineering applications as a soft microdevice element for drug delivery.

Morphology control of surfactant-assisted graphene oxide films at the liquid-gas interface.

Control of a two-dimensional (2D) structure of assembled graphene oxide (GO) sheets is highly desirable for fundamental research and potential applications of graphene devices. We show that an alkylamine surfactant, i.e., octadecylamine (ODA), Langmuir monolayer can be utilized as a template for adsorbing highly hydrophilic GO sheets in an aqueous subphase at the liquid-gas interface. The densely packed 2-D monolayer of such complex films was obtained on arbitrary substrates by applying Langmuir-Schaefer or Langmuir-Blodgett technique. Morphology control of GO sheets was also achieved upon compression by tuning the amount of spread ODA molecules. We found that ODA surfactant monolayers prevent GO sheets from sliding, resulting in formation of wrinkling rather than overlapping at the liquid-gas interface during the compression. The morphology structures did not change after a graphitization procedure of chemical hydrazine reduction and thermal annealing treatments. Since morphologies of graphene films are closely correlated to the performance of graphene-based materials, the technique employed in this study can provide a route for applications requiring wrinkled graphenes, ranging from nanoelectronic devices to energy storage materials, such as supercapacitors and fuel cell electrodes.

Thermoresponsive Gelatin Nanogels.

We present a novel tunable thermoresponsive gelatin nanogel that shows a volume transition at ∼32 °C. A thermally induced volume reduction of more than 30× is observed due to the helix to random coil transition of gelatin chains confined in the nanogels. The physical process and key factors influencing thermoresponsive properties are investigated using dynamic light scattering (DLS), transmission electron microscopy (TEM), and polarimetry. The thermoresponsive properties of this nanogel can be exploited in the development of new types of stimuli-responsive, biomedically relevant materials based on natural polymers.

Dynamic arrest of nematic liquid-crystal colloid networks.

We report interesting self-assembly structures of nematic liquid-crystal colloid (NLCC) networks, which are arrested during cooling from the isotropic temperature to room temperature. The NLCC is composed of sterically stabilized colloidal particles and a nematic liquid crystal (NLC) with nematic-isotropic transition temperature (T_{NI}) that is much higher than those of previously studied 4-Cyano-4'-pentylbiphenyl and N-(4-Methoxybenzylidene)-4-butylaniline. We find that the structure of NLCCs depends on T(NI), cooling rates, and boundary conditions, varying from cellular network to hierarchical fern structures in different length scales. Our time-lapse study shows that the transition from the cellular network to the fern structure directly corresponds to the transition from a spinodal demixing to a nucleation-and-growth mechanism.

Simulation study of seemingly Fickian but heterogeneous dynamics of two dimensional colloids.

A two-dimensional (2D) solid lacks long-range positional order and is diffusive by means of the cooperative motion of particles. We find from molecular dynamics simulations of hard discs that 2D colloids in solid and hexatic phases show seemingly Fickian but strongly heterogeneous dynamics. Beyond translational relaxation time, the mean-square displacement is linear with time, t, implying that discs would undergo Brownian diffusion and the self-part of the van Hove correlation function [G(s)(r,t)] might be Gaussian. But dynamics is still heterogeneous and G(s)(r,t) is exponential at large r and oscillatory with multiple peaks at intermediate length. We attribute the existence of several such peaks to the observation that there are several clusters of discs with discretized mobility. The cluster of marginally mobile discs grows with time and begins to percolate around translational relaxation time while clusters of fast discs emerge in the middle of the marginally mobile cluster.

Enhancement in the critical current density of C-doped MgB2 wire using a polyacrylic acid dopant.

C-doped MgB2 wires were fabricated from a polyacrylic acid (PAA) using a conventional in-situ PIT technique. The effects of the PAA content on the lattice parameter, microstructure, critical temperature (Tc) and critical current density (Jc) were examined. With increasing PAA content, the amount of MgO in the sample increased but the crystallinity, a-axis lattice parameter, and Tc of MgB2 wires decreased, indicating that the C that decomposed from PAA during heat treatment had substituted for B. All doped samples exhibited a higher Jc than the undoped sample at high magnetic field, and the Jc(B) property improved with increasing PAA content: for the 7 wt% doped sample, the Jc was approximately 3-times higher than that of the pristine sample (1.28 kA/cm2 vs. 3.43 kA/cm2) at 5 K and 6.6 T. The improved Jc(B) of the doped sample was attributed to the decreased grain size, enlarged lattice distortion and increased C doping level.

Shear melting of a colloidal glass.

We use confocal microscopy to explore shear melting of colloidal glasses, which occurs at strains of approximately 0.08, coinciding with a strongly non-Gaussian step size distribution. For larger strains, the particle mean square displacement increases linearly with strain and the step size distribution becomes Gaussian. The effective diffusion coefficient varies approximately linearly with shear rate, consistent with a modified Stokes-Einstein relationship in which thermal energy is replaced by shear energy and the length scale is set by the size of cooperatively moving regions consisting of approximately 3 particles.

Doping effect of CNT and nano-carbon in magnesium diboride bulk.

We fabricated carbon nanotube (CNT)- and nano-carbon (NC)-doped MgB2 using an in-situ process in order to improve the critical current density (J(c)) at high magnetic field. We then evaluated the effects of the doped carbon content on phase formation, microstructure, and critical properties. CNT had a diameter and length of 5-10 nm and 0.5-1 microm, respectively, and NC was a sphere with a diameter of 5-30 nm. The bulk MgB(2-x)C(x) samples with x = 0, 0.05, and 0.1 for NC and CNT were fabricated by pressing into pellets and then sintered at 900 degrees C for 30 min. NC was more effective than CNT for carbon doping at the B site in MgB2 and, therefore, the NC-doped MgB2 samples had a lower critical temperature (T(c)) of 35.0-34.7 K than that of the CNT-doped samples (36.4-36.1 K). In addition, the J(c)(B) behavior was improved when NC and CNT were doped due to doping effect. Microstructural observation suggested that the nano-sized and unreacted NC particles and the nanodomain MgB2 acted as effective flux pinning centers for the NC- and CNT-doped MgB2, respectively.

Chain conformation of poly(dimethyl siloxane) at the air/water interface by sum frequency generation.

This is to report a study of chain conformation of poly(dimethylsiloxane) (PDMS) in spread monolayers at the air/water interface (A/W) with the aid of vibrational sum frequency spectroscopy (VSFS). We find that methyl groups of PDMS chains at the interface are completely disordered in the dilute regime of the surface density. At higher surface densities, however, the two methyl groups on the repeating unit point into the air asymmetrically; one points more normal to the interface, whereas the other lies more parallel to the interface. In the first collapsed regime, where the surface pressure of the PDMS monolayer reaches a plateau value of 8.7 mN/m, the signal intensity at 2915 cm (-1), assigned to the symmetric vibrational frequency of the methyl groups, is found independent of the surface density. On the basis of this finding, we propose that PDMS chains, in the first collapse regime at the A/W, form asymmetric layers. Thus, our proposal lends support to earlier works by Langevin's group to refute a widely speculated helix model that was based on energy minimization in the crystalline state of PDMS. In short, the energy consideration in the bulk crystalline state does not provide meaningful guidance as to the chain conformation of the monolayer at the A/W.

Shear thickening and scaling of the elastic modulus in a fractal colloidal system with attractive interactions.

Dilute oil dispersions of fractal carbon black particles with attractive van der Waals interactions display continuous shear thickening followed by shear thinning at high shear rates. The shear thickening transition occurs at gamma c approximately 10(2)-10(3) s(-1) and is driven by hydrodynamic breakup of clusters. Pre-shearing dispersions at shear rates gamma>gamma c produces enhanced-modulus gels where G' approximately sigma pre-shear 1.5-2 and is directly proportional to the residual stress in the gel measured at a fixed sample age. The observed data can be accounted for using a simple scaling model for the breakup of fractal clusters under shear stress.

Gravitational stability of suspensions of attractive colloidal particles.

Colloidal suspensions are susceptible to gravitationally induced phase separation. This can be mitigated by the formation of a particle network caused by depletion attraction. The effectiveness of this network in supporting the buoyant weight of the suspension can be characterized by its compressional modulus. We measure the compressional modulus for emulsion networks induced by depletion attraction and present a model that quantitatively predicts their gravitational stability. We also determine the relationship between the strength of the depletion attraction and the magnitude of the compressional modulus.