Suppression in Mevalonate Synthesis Mediates Antitumor Effects of Combined Statin and γ-Tocotrienol Treatment

Statins directly inhibit 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) activity, while γ-tocotrienol, an isoform of vitamin E, enhances the degradation and reduces cellular levels of HMGR in various tumor cell lines. Since treatment with statins or γ-tocotrienol alone induced a dose-responsive inhibition, whereas combined treatment with subeffective doses of these agents resulted in a synergistic inhibition in +SA mammary tumor cell growth, studies were conducted to investigate the role of the HMGR pathway in mediating the antiproliferative effects of combined low dose statin and γ-tocotrienol. Treatment with 8 μM simvastatin inhibited cell growth and isoprenylation of Rap1A and Rab6, and supplementation with 2 μM mevalonate reversed these effects. However, the growth inhibitory effects of 4 μM γ-tocotrienol were not dependent upon suppression in mevalonate synthesis. Treatment with subeffective doses of simvastatin (0.25 μM), lovastatin (0.25 μM), mevastatin (0.25 μM), pravastatin (10 μM), or γ-tocotrienol (2 μM) alone had no effect on protein prenylation or mitogenic signaling, whereas combined treatment with these agents resulted in a significant inhibition in +SA cell growth, and a corresponding decrease in total HMGR, Rap1A and Rab6 prenylation, and MAPK signaling, and mevalonate supplementation reversed these effects. These findings demonstrate that the synergistic antiproliferative effects of combined low dose statin and γ-tocotrienol treatment are directly related to an inhibition in HMGR activity and subsequent suppression in mevalonate synthesis.     

Development of electronic textiles to support networks, communications, and medical applications in future U.S. military protective clothing systems.

The focus of this paper is on the development of textile-based wearable electronics that can be integrated into military protective clothing. A materials and manufacturing survey was conducted to determine the best performing and most durable materials to withstand the rigors of textile manufacturing and potential military use. Narrow woven technology was selected as one of the most promising textile manufacturing methods. A working wearable narrow fabric version of the Universal Serial Bus (USB), as well as a radiating conductor, were successfully developed and fabricated. A circular knit T-shirt with an integrated spiral bus was also developed. Military products developed include components of a personal area network providing data and power transport, and a body-borne antenna integrated into a load-bearing vest.     

REVERSE POTENTIAL PHENOMENA IN THE MEMBRANE-ELECTRODE (M-E) PROCESS

Conventional water treatment techniques typically suffer from severe limitations in selective removal and recovery of heavy metals from dilute solutions. For instance, treatment by pH control, chemical reduction, and chemical oxidation result in precipitation of heavy metaJs, which are subsequently landfilled. Ion exchange suffers from lack of selectivity in cation removal from multi-component mixtures, while electrochemical reduction has severe limitations in dilute solutions. In order to address the problem of selective heavy metal removal and recovery, development of the Membrane-Electrode (M-E) process was undertaken. The M-E process is a hybrid of electrochemical reduction and ion-exchange technologies and permits selective ion-exchange from dilute aqueous solutions.

High cation selectivities in the M-E process is due to controlled rate of ion-exchange. It has been discovered that cation exchange rates can be controlled by application of an electrical potential difference (pd), and that an inverse relationship exists between pd and the rate of ion-exchange. This behavior is termed as the “Reverse-Potential Phenomena”. Typically, the rate of ion-exchange in conventional ion-exchange processes is dependent upon the cation concentration in solution, and cation loading on the ion-exchange material; this rate cannot be controlled by external means.

Thus far, the M-E process has been effectively demonstrated for selective recovery of Pb²⁺ and Cu²⁺ ions from dilute aqueous binary and ternary cation solutions [,]. This paper focuses on the effect of Reverse-Potential phenomena on selectivity in the Cu²⁺ and Ni²⁺ binary solution mixture.     

Consistent Estimation of Linear and Non-linear Autoregressive Models with Markov Regime

An autoregressive process with Markov regime is an autoregressive process for which the regression function at each time-point is given by a (non-observable) Markov chain. We examine maximum likelihood estimation for such models and show consistency of a conditional maximum likelihood estimator. Also identifiability issues are discussed     

Antioxidant efficacy of chitosan/graphene functionalized superparamagnetic iron oxide nanoparticles

The antioxidant potential of superparamagnetic iron oxide nanoparticles functionalized with chitosan and graphene were examined in the present work. Coprecipitation technique was followed for the synthesis of iron oxide nanoparticles. Graphene-iron oxide nanocomposites were synthesized by mechanical mixing followed by the heat treatment at moderate temperature. The chitosan coated iron oxide nanoparticles were prepared by dispersing nanoparticles in chitosan solution. The nanoparticles/nanocomposites were characterized using XRD, SEM, TEM and HAADF-STEM for phase structure, morphology and elemental analysis. The superparamagnetic behavior of nanoparticles/nanocomposites were confirmed by magnetic measurements using vibrating sample magnetometry. Antioxidant efficacy of these nanoparticles/nanocomposites were investigated in terms of free radical scavenging and reducing potential using an array of in vitro assay system. Ferric reducing antioxidant power (FRAP) and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) were used for the antioxidant capacity. The investigation suggests that the graphene improves the antiradical response of iron oxide nanoparticles at higher concentration which is almost comparable to the ascorbic acid used as standard.     

Highly dispersible and uniform size Cu2ZnSnS4 nanoparticles for photocatalytic application

Highly dispersible, uniform size (～7 nm) single-phase Cu₂ZnSnS₄ nanoparticles have been synthesized by hydrothermal method using non-toxic surfactant (oleic acid). High resolution transmission electron microscopy image indicates good crystallinity of the Cu₂ZnSnS₄ nanoparticles with the growth along (1 1 2) plane. X-ray photoelectron spectroscopy analyses suggested that the formation of with Cu, Zn, and Sn in +1, +2 and +4 oxidation states. The optical absorption spectrum of Cu₂ZnSnS₄ nanoparticles exhibits an absorption in the visible region and its optical band gap was found to be ～1.72 eV, which could be much more appropriate for photocatalytic application under visible light irradiation. These Cu₂ZnSnS₄ nanoparticles have been shown high photocatalytic degradation activity of methylene blue (MB) dye in the presence of visible light irradiation. The rate constant (k) value of Cu₂ZnSnS₄ nanoparticles is found to be 0.0144 min^?1. We have discussed the mechanism of dye degradation process that drives the photocatalytic degradation process. The reusability of the Cu₂ZnSnS₄ nanoparticles for the dye degradation is also demonstrated.     

Next generation stamping dies — controllability and flexibility

In sheet metal forming, external energy is transferred to sheet metal through a set of tooling to plastically deform a workpiece. The design of the tooling and its associated forming process parameters play important roles in this manufacturing process since they directly affect the quality and cost of the final product. With increasing demands from customers, government regulations, and global competition, the controllability and flexibility of stamping dies have been challenged. In this paper, we will summarize the research activities conducted at the Advanced Materials Processing Laboratory at Northwestern University in the area of sheet metal forming. An overview of our approach towards the system will be given followed by a summary of individual projects in the areas of failure prediction, design and control of a variable binder force, and the segmented die design with local adaptive controllers.     

N-Containing Carbons Derived from Microporous Coordination Polymers for Use in Post-Combustion Flue Gas Capture

Herein, novel carbons that, owing to a high density of micropores (up to 79%) and N-content (up to 14.9%), offering exciting potential for post-combustion CO₂ capture are reported. Given that little is known about how starting materials impact the structure and performance of carbons, three different microporous materials are pyrolyzed. These include a Co-(metal-organic framework) (MOF), a Co-MOF-polymer composite, and a coordination polymer derived from the same monomer and cobalt ions. Notably, the cobalt, which is required to drive the polymerization, is subsequently leached from the carbons via acid for its reuse in MOF synthesis. Next, various metrics including CO₂ capacity, selectivity, isosteric heat of adsorption, breakthrough time and cyclability are assessed. The acid treated carbons adsorb 0.21, 0.99, and 1.11 mmol CO₂ g⁻¹, respectively, (313 K, 0.15 bar) with CO₂/N₂ selectivity ranging from 37 to 52. Due to superior capacity, the polymer-derived carbons also reveal impressive breakthrough times in simulated flue gas mixtures (15% CO₂/85% N₂, 80% RH, 313 K) ranging from 33 to 40 min g⁻¹. Similar performance is also observed under dry conditions and after pre-saturation with water for 1.5 h. Remarkably, no loss in working capacity is observed after 100 CO₂ TSA cycles (313 K/393 K).