Magnetic Assembly of a Multifunctional Guidance Conduit for Peripheral Nerve Repair

Nerve growth conduits are designed to support and promote axon regeneration following nerve injuries. Multifunctionalized conduits with combined physical and chemical cues, are a promising avenue aimed at overcoming current therapeutic barriers. However, the efficacious assembly of conduits that promote neuronal growth remains a challenge. Here, a biomimetic regenerative gel is developed, that integrates physical and chemical cues in a biocompatible “one pot reaction” strategy. The collagen gel is enriched with magnetic nanoparticles coated with nerve growth factor (NGF). Then, through a remote magnetic actuation, highly aligned fibrillar gel structure embedded with anisotropically distributed coated nanoparticles, combining multiple regenerating strategies, is obtained. The effects of the multifunctional gels are examined in vitro, and in vivo in a 10-mm rat sciatic nerve injury model. The magneto-based therapeutic conduits demonstrate oriented and directed axonal growth, and improve nerve regeneration in vivo. The study of multifunctional guidance scaffolds that can be implemented efficiently and remotely provides the foundation to a novel therapeutic approach to overcome current medical obstacles for nerve injuries.     

Young drivers’ attitudes toward accompanied driving: A new multidimensional measure

Four studies were conducted in order to develop and validate a multidimensional instrument to assess attitudes toward accompanied driving among young drivers. Study 1 (n = 841) focused on developing the Attitudes Toward Accompanied Driving Scale (ATADS), a self-report scale based on five previously conceptualized domains of attitudes. Factor analysis revealed the five hypothesized factors: Tension, Relatedness, Disapproval, Avoidance, and Anxiety. In addition, significant associations were found between these factors and gender, age, and the assessment of reckless driving as risky. Study 2 (n = 651) adopted a developmental approach, comparing the attitudes of participants in various stages of licensure. Disapproval and Tension were found to be higher, and Relatedness lower, among participants who had not yet begun driving instruction than among those who were taking driving lessons or had already obtained a license. Study 3 (n = 160) revealed associations between the five ATADS factors and perceived driving costs and benefits. In Study 4 (n = 193), associations were found between these factors and driver's self-image, with a combination of ATADS factors, self-image, and gender contributing to the explained variance of two outcome variables: driving self-efficacy, and reported frequency of reckless driving. The discussion focuses on the validity and utility of the new measure of young drivers’ attitudes toward accompanied driving, stressing its practical implications for road safety.     

On nonaqueous electrochemical behavior of titanium and Ti compounds

In this study, we examined the electrochemical behavior of titanium and Ti⁴⁺ compounds in THF solutions. Tetra butyl ammonium chloride (TBACl) was used as supporting electrolyte in order to increase the ionic conductivity of the solutions. Electrodeposition of pure titanium could not be obtained. A variety of analytical techniques have been used in conjunction with electrochemical methods in order to analyze the reduction process of Ti⁴⁺. These included Raman and UV-vis spectroscopy, ICP and CHNS elemental analyses. Ti⁴⁺ is being reduced to Ti³⁺ in TiCl₄/THF/TBACl solutions.In addition we show that metallic titanium can be electrochemically dissolved from an organo-metallic electrolyte solution comprising EtAlCl₂ and LiCl in THF. The product is Ti⁴⁺. While LiCl is insoluble in THF it reacts with EtAlCl₂ to form ionic species. Hence, these solutions possessed reasonable ionic conductivity.We could not obtain electroactive Ti⁴⁺ with TiBr₄ or TiI₄ as starting materials, in similar solutions.     

Partitioning sequential circuits for pseudoexhaustive testing

In this paper, we present an algorithm for partitioning sequential circuits. This algorithm is based on an analysis of a circuit's primary input cones and fanout values (PIFAN), and it uses a directed acyclic graph to represent the circuit. An invasive approach is employed, which creates logical and physical partitions by automatically inserting reconfigurable test cells and multiplexers. The test cells are used to control and observe multiple partitioning points, while the multiplexers expand the controllability and observability provided by the test cells. The feasibility and efficiency of our algorithm are evaluated by partitioning numerous standard digital circuits, including some large benchmark circuits containing up to 5597 gates. Our algorithm is based upon pseudoexhaustive testing methods where fault simulation is not required for test-pattern generation and grading; hence, engineering design time and cost are further reduced     

Hydrogen/deuterium exchange kinetics of cytochrome C: An electrospray ionization fast flow experiment

New experiments are described in which the gas phase hydrogen/deuterium (H/D) exchange kinetics is studied for multiply-protonated cytochrome c ions with +10 to +17 charges. The experimental technique involves electrospray ionization (ESI) combined with a fast-flow method. Experimental results are presented including (1) average rate constants for H/D exchange, (2) overall decay kinetics of the reactant ion, and (3) sets of profiles for consecutive deuterium exchanges as a function of the flow rate of ND₃ as the deuterating agent. The maximum number of exchanged hydrogen atoms and the exchange rate are observed to increase with increasing charge. The +13 state demonstrates special reactivity with a reactant ion decay constant of 2.5 × 10⁻⁹ cc/molecule's. Further insight into the H/D exchange mechanism is anticipated upon analysis of the data with a newly developed algorithm for extracting site-specific rate constants from profiles for H/D exchange in gas phase protonated amino acids, their clusters, and peptides. The algorithm minimizes the mutual entropy or the Kullback-Leibler information divergence between the observed concentrations and a chosen model.     

Holdup and extraction characteristics of jojoba meal

Holdup and drainage characteristics have been determined for three jojoba meals of different nature and size distribution, using hexane and isopropanol as solvents. Density and viscosity properties of the oil-solvent solutions have been measured. The experimental information should be of value in the design of solvent extraction equipment for jojoba nuts.     

Hierarchical Tumor Microenvironment‐Responsive Nanomedicine for Programmed Delivery of Chemotherapeutics

Nanomedicines have been demonstrated to have passive or active tumor targeting behaviors, which are promising for cancer chemotherapy. However, most nanomedicines still suffer from a suboptimal targeting effect and drug leakage, resulting in unsatisfactory treatment outcome. Herein, a hierarchical responsive nanomedicine (HRNM) is developed for programmed delivery of chemotherapeutics. The HRNMs are prepared via the self‐assembly of cyclic Arg‐Gly‐Asp (RGD) peptide conjugated triblock copolymer, poly(2‐(hexamethyleneimino)ethyl methacrylate)‐poly(oligo‐(ethylene glycol) monomethyl ether methacrylate)‐poly[reduction‐responsive camptothecin] (PC7A‐POEG‐PssCPT). In blood circulation, the RGD peptides are shielded by the POEG coating; therefore, the nanosized HRNMs can achieve effective tumor accumulation through passive targeting. Once the HRNMs reach a tumor site, due to the hydrophobic‐to‐hydrophilic conversion of PC7A chains induced by the acidic tumor microenvironment, the RGD peptides will be exposed for enhanced tumor retention and cellular internalization. Moreover, in response to the glutathione inside cells, active CPT drugs will be released rapidly for chemotherapy. The in vitro and in vivo results confirm effective tumor targeting, potent antitumor effect, and reduced systemic toxicity of the HRNMs. This HRNM is promising for enhanced chemotherapeutic delivery.     

Honey bees find the shortest path: a collective flow-mediated approach

Artificial Life and Robotics - Honey bees (Apis mellifera L.) are social insects that makes frequent use of volatile pheromone signals to collectively navigate unpredictable and unknown...     

Real‐time hybrid control of electrohydraulic active suspension

Electrohydraulic actuators are an attractive choice for active suspension, because these systems provide a high power‐to‐weight ratio. However, their dynamics are highly nonlinear. In addition, the use of one simple controller for both position and force is complicated, because there is a compromise between them in the case of active suspension. Most existing controllers do not efficiently fulfill the requirements, because only one state variable is considered. In this paper, we address these problems by developing a new hybrid controller for both position and force and implementing it in a real‐time test bench. Our goal is to control the vertical position of the passenger seat while tracking the force transmitted to passengers and keeping it within tolerable and comfortable limits. Therefore, the proposed controller is a combination of two controllers. Its flexible structure redirects the control signal to control the proper controlled state variable. The real‐time results of the newly designed hybrid controller are compared with those obtained using a classical proportional integral derivative controller, because this is the most widely used controller in the industry. As expected, the proposed controller demonstrates better performance in real‐time operation. Copyright © 2017 John Wiley & Sons, Ltd.