Evaluation of Chokeberry/Carboxymethylcellulose Hydrogels with the Addition of Disaccharides: DART-TOF/MS and HPLC-DAD Analysis

With the growing awareness of the importance of a healthy diet, the need for the development of novel formulations is also on the rise. Chokeberry products are popular among consumers since they are a rich source of polyphenols that are responsible for antioxidant activity and other positive effects on human health. However, other natural food ingredients, such as disaccharides, can affect their stability. The aim of this study was to investigate the influence of disaccharides addition on the polyphenol composition of chokeberry hydrogels. Hydrogels were prepared from chokeberry juice and 2% of carboxymethylcellulose (CMC) with the addition of 30%, 40%, or 50% of disaccharides (sucrose or trehalose). Samples were analyzed using DART-TOF/MS. The method was optimized, and the fingerprints of the mass spectra have been statistically processed using PCA analysis. Prepared samples were evaluated for total polyphenols, monomeric anthocyanins, and antioxidant activity (FRAP, CUPRAC, DPPH, ABTS assays) using spectrophotometric methods. Individual polyphenols were evaluated using HPLC-DAD analysis. Results showed the addition of disaccharides to 2% CMC hydrogels caused a decrease of total polyphenols. These findings confirm proper formulation is important to achieve appropriate retention of polyphenols.     

Resolving the Mechanism of Acoustic Plasmon Instability in Graphene Doped by Alkali Metals

Graphene doped by alkali atoms (ACx) supports two heavily populated bands (π and σ) crossing the Fermi level, which enables the formation of two intense two-dimensional plasmons: the Dirac plasmon (DP) and the acoustic plasmon (AP). Although the mechanism of the formation of these plasmons in electrostatically biased graphene or at noble metal surfaces is well known, the mechanism of their formation in alkali-doped graphenes is still not completely understood. We shall demonstrate that two isoelectronic systems, KC8 and CsC8, support substantially different plasmonic spectra: the KC8 supports a sharp DP and a well-defined AP, while the CsC8 supports a broad DP and does not support an AP at all. We shall demonstrate that the AP in an ACx is not, as previously believed, just a consequence of the interplay of the π and σ intraband transitions, but a very subtle interplay between these transitions and the background screening, caused by the out-of-plane interband C(π)→A(σ) transitions.     

Analysis of flow and mixing in screw elements of corotating twin‐screw extruders via SPH

Due to its meshless nature, the smoothed particle hydrodynamics method (SPH) provides high potential for the simulation of free‐surface flows and mixing in complex geometries. We used SPH to analyze the flow inside five typical screw elements of corotating twin‐screw extruders, two conveying elements, two kneading elements and a mixing element. Our results show conveying capabilities, pressure generation and power input for various operation states, completely and partially filled. We conducted a detailed mixing analysis based on tracer particles, which yielded the time evolution of the intensity of segregation for different tracers. From that, we determined exponential mixing rates, which describe the relative decrease of the intensity of segregation per screw revolution and characterize the mixing performance in different operation states. This provides valuable input information for simplified models of extruders, which are relevant to industrial applications and can significantly contribute to the efficient design, optimization and scale‐up of extruders. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2451–2463, 2017     

Determination of tensile strength of glass fiber straps

Glass fibers straps have been used for strengthening of masonry and concrete structures in the last decade. Recently, their use has become greater. This paper describes the research of measuring tensile strength of dry glass fiber straps as well as straps that were made of glass fibers and epoxy coating. The effect of strap widths, the effect of loading speeds and the effect of epoxy coating placed on fiber straps, on tensile strength of straps have been analyzed. Differences of tension strengths of fiber straps with and without epoxy coating are shown.     

Integral inequalities of systems and the estimate for solutions of certain nonlinear two-dimensional fractional differential systems

This paper generalizes the results for the constructions of explicit bounds and the qualitative properties for the solutions of certain two-dimensional fractional differential systems established in a recent paper of the authors. The main generalizations come from an elementary inequality and by means of the modification of Medve?’s de-singular approach.     

Flank wear regulation using artificial neural networks

Tool wear regulation highly influences product quality and the safety and productivity of machining processes. Hence, it is one of the most important elements in the supervisory control of machine tools. The development of this type of machine tool adaptive control is practically at its infancy because there are still no industrial solutions concerning robust, reliable, and highly precise continuous tool wear estimators. Therefore, this paper primarily aims at the determination of a tool wear regulation model that can ensure the maximum allowed amount of tool wear rate within a predefined machining time, while simultaneously maintaining a high level of process productivity. The proposed model is structured using Radial Basis Function Neural Network controller and Modified Dynamical Neural Network filter. It is analysed using an analytical tool wear model with experimentally adjusted parameters.     

Type 1 Diabetes Mellitus and the First Trimester Placenta: Hyperglycemia-Induced Effects on Trophoblast Proliferation,Cell Cycle Regulators,and Invasion

Type 1 diabetes mellitus (T1DM) is associated with reduced fetal growth in early pregnancy, but a contributing role of the placenta has remained elusive. Thus, we investigated whether T1DM alters placental development in the first trimester. Using a protein array, the level of 60 cell-cycle-related proteins was determined in human first trimester placental tissue (gestational week 5–11) from control (n = 11) and T1DM pregnancies (n = 12). Primary trophoblasts (gestational week 7–12, n = 32) were incubated in the absence (control) or presence of hyperglycemia (25 mM D-glucose) and hyperosmolarity (5.5 mM D-glucose + 19.5 mM D-mannitol). We quantified the number of viable and dead trophoblasts (CASY Counter) and assessed cell cycle distribution (FACS) and trophoblast invasion using a transwell assay. T1DM was associated with a significant (p < 0.05) downregulation of Ki67 (−26%), chk1 (−25%), and p73 (−26%). The number of viable trophoblasts was reduced under hyperglycemia (−23%) and hyperosmolarity (−18%), whereas trophoblast invasion was increased only under hyperglycemia (+6%). Trophoblast cell death and cell cycle distribution remained unaffected. Collectively, our data demonstrate that hyperglycemia decreases trophoblast proliferation as a potential contributing factor to the reduced placental growth in T1DM in vivo.     

Energy-efficiency analyses of heterogeneous macro and micro base station sites

Due to the introduction of newer technologies like Long Term Evolution (LTE) in already deployed cellular access networks, changes in the energy-efficiency of networks consisting predominantly of macro base station sites (BSSs) can be expected. An investigation has been performed for two prominent energy metrics of cellular networks: Power per Unit Area (PUA) and Energy per bit and Unit Area (EbUA). Analytical relations have been developed that express the influence of parameters such as BSs’ transmit (Tx) powers, inter-site distances (ISDs), and a number of heterogeneous macro or LTE micro BSSs on the PUA and EbUA. It has been shown that appropriate selection of these parameters can ensure significant energy savings. Besides the possibility of finding an optimal trade-off among ISDs and Tx powers of macro BSSs, which will minimize PUA and maximize EbUA, adding micro LTE BSs to such heterogeneous networks contributes to the improvement of network energy efficiency.     

Site-Controlled Uniform Ge/Si Hut Wires with Electrically Tunable Spin–Orbit Coupling

Semiconductor nanowires have been playing a crucial role in the development of nanoscale devices for the realization of spin qubits, Majorana fermions, single photon emitters, nanoprocessors, etc. The monolithic growth of site-controlled nanowires is a prerequisite toward the next generation of devices that will require addressability and scalability. Here, combining top-down nanofabrication and bottom-up self-assembly, the growth of Ge wires on prepatterned Si (001) substrates with controllable position, distance, length, and structure is reported. This is achieved by a novel growth process that uses a SiGe strain-relaxation template and can be potentially generalized to other material combinations. Transport measurements show an electrically tunable spin–orbit coupling, with a spin–orbit length similar to that of III–V materials. Also, charge sensing between quantum dots in closely spaced wires is observed, which underlines their potential for the realization of advanced quantum devices. The reported results open a path toward scalable qubit devices using nanowires on silicon.     

Simultaneous stabilization and trajectory tracking of underactuated mechanical systems with included actuators dynamics

The paper deals with a novel control algorithm for simultaneous stabilization and trajectory tracking of underactuated nonlinear mechanical systems (UNMS) with included actuators dynamics. Simultaneous stabilization and trajectory tracking refer to arbitrary chosen actuated and unactuated degrees of freedom (DOF) of the system. The proposed control approach can be applied both to the second-order nonholonomic systems and the systems with input coupling, while a general model of actuators dynamics includes electrical, pneumatic, and hydraulic drives. Control law is based on linear combination of two control signals, where the first signal is designed to separately control only actuated DOF, and second to separately control only unactuated DOF. Simulation example of rotational inverted pendulum driven by electrical DC motor is presented, showing the effectiveness of the proposed approach.