A Multistimuli Responsive, Flexible Luminescent Framework and Its Applicability in Anticounterfeiting

A linear distyrylanthracene derivative (DDATAn) with two diaminotriazine (DAT) groups acting as the hydrogen bond (H-bond) units was designed and synthesized in order to construct flexible organic porous crystals. H-bonds between the DAT moieties helped the molecules to construct a double interpenetrated two-dimensional layer, and the stacking between layers provided a H-bonded organic framework (X-HOF-3) with one-dimensional solvent channels. When X-HOF-3 was placed in contact with methanol, the fluorescent colors of the HOF exhibited an apparent bathochromic shift. More interestingly, the methanol-activated HOF was able to rapidly adsorb water from the air, which was accompanied by a change in fluorescent color from yellow to red. Under heating, water was released from the HOF and the fluorescent color returned to yellow. Water molecules in the pores were also able to be released after an applied mechanical force disrupted the ordered structure of the HOF. Based on these stimuli-responsive properties, these HOFs can be used as advanced functional materials in anticounterfeiting applications.

Guest-Regulated Luminescence and Force-Stimuli Response of a Hydrogen-Bonded Organic Framework

Guest molecules may endow porous materials with new or enhanced properties as well as functions. Here, a porous hydrogen-bonded organic framework (HOF) constructed from a three-armed triphenylamine derivative is used to investigate how guests regulate photoluminescence and trigger force-stimuli response. It was found that guest solvents in pores might regulate HOF's luminescence. Interestingly, acetic acid as a guest endowed HOF materials with longer emission wavelengths and triggered the responses to mechanical force stimuli. Under shear force, an obvious blueshift in emission spectra was observed because of the loss of free guests and the conversion of π-stacking model. Further blue-shifted emission appeared while the bound guests were completely removed by heating. Mechanofluorochromic HOF materials could be regenerated through recrystallization and adsorbing guest. Conversely, HOFs with other guests and activated HOFs only resulted in a slight change in their fluorescence behaviors after force stimuli.

Highly Adsorptive and Magneto-Inductive Guefoams (Multifunctional Guest-Containing Foams) For Enhanced Energy-Efficient Preconcentration and Management of VOCs

The design of multifunctional materials is a current demand for high-end technological applications that need to combine different functions unable to be accomplished by a single material. The aim of this work is to present, at first glance, a new family of recently patented multifunctional porous materials developed by locating granular phases with specific functionality (guests) within the cavities of open-pore cellular materials (hosts) and, at second glance, the use of a set of these materials for the preconcentration and management of volatile organic compounds (VOCs). These materials (herein known as Guefoams, acronym for Guest-containing foams), present host foams and guest phases that are not bonded and therefore allow fluids to pass through. The processing method is the gas pressure infiltration of a host precursor into preforms containing particulate guest phases covered by a NaCl martyr coating, which is later dissolved in water. The manuscript shows the manufacture and characterization of a specific set of Guefoams composed of aluminum foams that incorporate both steel particles and activated carbon particles as guest phases into the same material. These guest phases make the materials highly adsorbent and susceptible to rapid desorption by magnetic induction, two properties never achieved with traditional foams that transform these materials into perfect candidates for preconcentration and energy-efficient management of VOCs. The manuscript concludes with a discussion on advisible properties to consider when exploring the use of these materials in the mentioned applications.

Chemical Detection Using a Metal-Organic Framework Single Crystal Coupled to an Optical Fiber

The quantitative detection and real-time monitoring of target chemicals in the liquid phase are made possible by combining the tailored adsorption properties of metal-organic framework (MOF) material and the precise measuring capabilities of an optical fiber (OF) Fabry-Pérot interferometer (FPI) device. As the single-crystal MOF host adsorbs target analyte guests from the environment, its dielectric properties change causing the reflection spectrum derived from the FPI device to shift. A single crystal of HKUST-1 was attached to the end-face of an OF to form the sensor OF∪MOF (∪, union). The sensor's response curve was accurately measured using low concentrations of the target analyte nitrobenzene, an explosive simulant. Additionally, the uptake rate of nitrobenzene into the MOF single crystal was characterized. The experimental results show that the sensor achieved quantitative and real-time adsorption measurements of a target analyte.

Zoo visitor perceptions, attitudes, and conservation intent after viewing African elephants at the San Diego Zoo Safari Park

Elephants in the wild face several conservation issues. With the rebranding of zoos as conservation and education pioneers, they have the ability to both educate and inspire guests to action. The purpose of this research was to analyze visitor perceptions and attitudes toward elephant conservation and outcomes post-exhibit visit. A one-page survey was randomly administered to assess perceptions of elephant behavior, attitudes about elephant conservation, and intended conservation-related outcomes from September 2013 to January 2014. Principle component analysis identified three major components: concern for elephants in zoos, importance of elephants in the wild, and modification of nature. Visitors who scored highly on conservation intent were those with positive attitudes towards elephants in the wild and negative attitudes regarding the modification of nature. The greatest changes in conservation intent were a result of a self-reported up-close encounter and the ability to witness active behaviors. Providing guests with the opportunity to witness or experience such occurrences may aid in a more successful delivery of the zoo's conservation message. Further research into guest emotions and affective states in relation to viewing elephants in a zoological institution would provide greater insight into improving the guest experience and helping zoos meet their conservation mission. Zoo Biol. 35:355-361, 2016. © 2016 Wiley Periodicals, Inc.

Functionalised particles using dry powder coating in pharmaceutical drug delivery: promises and challenges

INTRODUCTION

Production of functionalised particles using dry powder coating is a one-step, environmentally friendly process that paves the way for the development of particles with targeted properties and diverse functionalities.

AREAS COVERED

Applying the first principles in physical science for powders, fine guest particles can be homogeneously dispersed over the surface of larger host particles to develop functionalised particles. Multiple functionalities can be modified including: flowability, dispersibility, fluidisation, homogeneity, content uniformity and dissolution profile. The current publication seeks to understand the fundamental underpinning principles and science governing dry coating process, evaluate key technologies developed to produce functionalised particles along with outlining their advantages, limitations and applications and discusses in detail the resultant functionalities and their applications.

EXPERT OPINION

Dry particle coating is a promising solvent-free manufacturing technology to produce particles with targeted functionalities. Progress within this area requires the development of continuous processing devices that can overcome challenges encountered with current technologies such as heat generation and particle attrition. Growth within this field requires extensive research to further understand the impact of process design and material properties on resultant functionalities.