Multilevel seismic demand prediction for acceleration-sensitive non-structural components

Existing methods to predict the seismic demand of non-structural components in current seismic design guidelines do not generally consider the intensity of the design earthquake and the expected performance level of the lateral load bearing system. This limitation is especially important in performance-based design of buildings and industrial facilities in seismic regions. In this study, a novel multilevel approach is proposed to predict the seismic demand of acceleration-sensitive non-structural components using two new parameters obtained based on site seismicity and seismic capacity of the lateral load carrying system. The main advantage of the new method is to take into account the seismic hazard level and the expected performance level of structure in the calculation of the seismic demand of non-structural components. Based on the results of a comprehensive reliability study on 5 and 10-storey steel frame structures, the efficiency of the proposed approach is demonstrated compared to the conventional seismic design methods. The results, in general, indicate that the current standards may provide inaccurate predictions and lead to unsafe design solutions for acceleration-sensitive non-structural components, especially in the case of higher seismic intensity or medium performance levels. It is shown that the estimated accelerations by NIST and ASCE suggested equations are up to 50% and 80% lower than the minimum demand accelerations calculated for the studied structures, respectively, under the selected design conditions. Based on the results of this study, a simple but efficient design equation is proposed to estimate the maximum acceleration applied to non-structural components for different earthquake intensity levels and performance targets

One-pot RAFT and fast polymersomes assembly: a ‘beeline’ from monomers to drug-loaded nanovectors

Rapid and simple routes to functional polymersomes are increasingly needed to expand their clinical or industrial applications. Here we describe a novel strategy where polymersomes are prepared through an in-line process in just a few hours, starting from simple acrylate or acrylamide monomers. Using Perrier's protocol, well-defined amphiphilic diblock copolymers formed from PEG acrylate (mPEGA480), 2-(acryloyloxy)ethyl-3-chloro-4-hydroxybenzoate (ACH) or 2-(3-chloro-4-hydroxybenzamido)ethyl acrylate (CHB), have been synthesised by RAFT polymerisation in one-pot, pushing the monomer conversion for each block close to completion (≥94%). The reaction mixture, consisting of green biocompatible solvents (ethanol/water) have then been directly utilised to generate well-defined polymersomes, by simple cannulation into water or in a more automated process, by using a bespoke microfluidic device. Terbinafine and cyanocobalamine were used to demonstrate the suitability of the process to incorporate model hydrophobic and hydrophilic drugs, respectively. Vesicles size and morphology were characterised by DLS, TEM, and AFM. In this work we show that materials and experimental conditions can be chosen to allow facile and rapid generation drug-loaded polymersomes, through a suitable in-line process, directly from acrylate or acrylamide monomer building blocks

Smart, Biocompatible Polymersomes for Targeted Delivery of Therapeutic Agents to Cancerous Tumors

Chemotherapeutics are the major treatment options for cancer. Although we cannot underestimate the importance of the chemotherapeutic drugs, their systemic toxicity is an important limiting factor for their use. Therefore, altering the biodistribution of the therapeutics can be an important step in treating the cancer patients. Thus, there is a growing interest in developing smart, targeted, stimuli responsive, drug delivery vehicles employing nanotechnalogy. The vehicles are often engineered to deliver the theranostics to the tumor microenvironment (extracellular matrix) or intracellular environment (e.g. cytosol, nucleus, mitochondria). The physiochemical changes in the cancerous tissues (e.g. leaky vasculature, proteins overexpression on the cell surface, overexpression of proteolytic enzymes, increased reducing agents concentration, decreased pH, and hypoxia) offer tremendous opportunities for selectively targeting the malignancies. Polymersomes are robust polymeric vesicles which have shown promising drug delivery capabilities. Both hydrophilic and hydrophobic compounds can be loaded to the vesicles. The polymersome's building blocks can be chemically manipulated to provide them with the optimum release profile. Furthermore, the surface of the polymersomes can be decorated with targeting moieties such as peptides, antibodies, or small molecules. We have developed smart, targeted, stimuli responsive polymersomes to combat pancreatic and prostate cancers.National Institutes of Health (NIH)National Science Foundation (NSF

Targeted Drug Delivery in Pancreatic Cancer

Tayebeh Anajafi Marzijarani, 2017 North Dakota State University Three Minute Thesis (3MT) competition champion, talks about her research on targeted drug delivery for pancreatic cancer

Sol-gel growth of TiO2 nanocrystals in n-heptan and their deposition for application in dye sensitized solar cells

In this study, TiO2 nanocrystals were prepared by sol-gel method through the hydrolysis of the titanium tetraisopropoxide in n-heptan solution. The beneficial role of n-heptan solvent was the dilution of the reacting precursors. This could consequently create smaller TiO2 nanocrystals and a better powder effective area. The anatase phase TiO2 nanopowder was achieved by performing an annealing process at 450 ˚C for 1h. Then, the TiO2 nanocrystals were added to an aqueous solution of polyethylene glycol with suitable concentration, as a pastiness factor, to form a viscous TiO2 paste . Finally the prepared paste was deposited on glass FTO substrates by standard doctor blade method and the photoanode of the dye sensitized solar cells  was prepared.Then other steps, consisting of dye adsorption, preparation of platinum counter electrode and injection of  electrolyte were performed. The results demonstrated that the energy conversion efficiency was maximum for the cell with 15 μm photoanode thickness. The photovoltaic parameters of this cell were measured as 12.44 mA/cm2 , 655 mV, 0.55 and 4.4 % for the Jsc, Voc, FF and efficiency, respectively.&nbsp

Static output-feedback vibration control of seismically excited buildings: an effective multistep approach

Static output-feedback (SOF) controllers are particularly interesting for vibration control of complex structures under a multiactuation scheme. In this chapter, we present a novel iterative linear matrix inequality computational procedure that allows designing high-performance SOF controllers for vibration control of multistory buildings equipped with a distributed set of interstory actuators. The effectiveness of the proposed methodology is illustrated by designing an SOF H-infinity controller for the seismic protection of a 20-story building equipped with a complete set of interstory actuators and a system of collocated interstory-velocity sensors. Numerical simulations of the building response using a near-fault impulsive-type seismic disturbance demonstrate the high-performance characteristics of the obtained SOF controller and its robustness against broadband seismic excitations.This work was partially supported by the Spanish Ministry of Economy and Competitiveness under Grant DPI2015-64170-R (MINECO/FEDER).Peer ReviewedPostprint (author's final draft

Acridine Orange Conjugated Polymersomes for Simultaneous Nuclear Delivery of Gemcitabine and Doxorubicin to Pancreatic Cancer Cells

Considering the systemic toxicity of chemotherapeutic agents, there is an urgent need to develop new targeted drug delivery systems. Herein, we have developed a new nuclear targeted, redox sensitive, drug delivery vehicle to simultaneously deliver the anticancer drugs gemcitabine and doxorubicin to the nuclei of pancreatic cancer cells. We prepared polymeric bilayer vesicles (polymersomes), and actively encapsulated the drug combination by the pH gradient method. A redox-sensitive polymer (PEG–S–S–PLA) was incorporated to sensitize the formulation to reducing agent concentration. Acridine orange (AO) was conjugated to the surface of the polymersomes imparting nuclear localizing property. The polymersomes’ toxicity and efficacy were compared with those of a free drug combination using monolayer and three-dimensional spheroid cultures of pancreatic cancer cells. We observed that the redox sensitive, nuclear-targeted polymersomes released more than 60% of their encapsulated contents in response to 50 mM glutathione. The nanoparticles are nontoxic; however, the drug encapsulated vesicles have significant toxicity. The prepared formulation can increase the drug’s therapeutic index by delivering the drugs directly to the cells’ nuclei, one of the key organelles in the cells. This study is likely to initiate research in targeted nuclear delivery using other drug formulations in other types of cancers