Poly(ε-caprolactone)-based additives: Plasticization efficacy and migration resistance

A family of poly(caprolactone) (PCL)-based oligomeric additives was evaluated as plasticizers for poly(vinyl chloride) (PVC). We found that the entire family of additives, which consist of a PCL core, diester linker, and alkyl chain cap, were effective plasticizers that improve migration resistance. The elongation at break and tensile strength of the blends made with the PCL-based additives were comparable to blends prepared with diisononyl phthalate (DINP), a plasticizer typically used industrially, and diheptyl succinate (DHPS), an alternative biodegradable plasticizer. Increasing concentration was found to decrease glass transition temperature (T_g) and increase elongation at break, confirming their role as functional plasticizers. We found that all of the PCL-based plasticizers exhibited significantly reduced leaching into hexanes compared to DINP and DHPS. The PCL-based plasticizers with shorter carbon chain lengths reduced leaching more than those with longer carbon chain lengths.     

The cleanroom-free rapid fabrication of a liquid conductivity sensor for surface water quality monitoring

Conductivity is an important issue of water quality detection. Although there are a number of microfluidic liquid conductivity sensors, most of them were difficult to fabricate and required cleanroom facilities, which significantly increased the cost of sensors. Here, we presented a novel liquid conductivity sensor that was built on interdigitated copper electrodes. Microscale sensor electrodes can be fabricated through the modified microfabrication process without any help of cleanroom facilities. In comparison with FEA simulation and commercial conductivity device, measured results showed that the fabricated liquid conductivity sensor was able to measure a wide range of liquids. Considering the ease of fabrication and its low cost, the cleanroom-free fabricated sensors have much potential for water quality monitoring.     

Interactions Between Tumor Biology and Targeted Nanoplatforms for Imaging Applications

Although considerable efforts have been conducted to diagnose, improve, and treat cancer in the past few decades, existing therapeutic options are insufficient, as mortality and morbidity rates remain high. Perhaps the best hope for substantial improvement lies in early detection. Recent advances in nanotechnology are expected to increase the current understanding of tumor biology, and will allow nanomaterials to be used for targeting and imaging both in vitro and in vivo experimental models. Owing to their intrinsic physicochemical characteristics, nanostructures (NSs) are valuable tools that have received much attention in nanoimaging. Consequently, rationally designed NSs have been successfully employed in cancer imaging for targeting cancer‐specific or cancer‐associated molecules and pathways. This review categorizes imaging and targeting approaches according to cancer type, and also highlights some new safe approaches involving membrane‐coated nanoparticles, tumor cell‐derived extracellular vesicles, circulating tumor cells, cell‐free DNAs, and cancer stem cells in the hope of developing more precise targeting and multifunctional nanotechnology‐based imaging probes in the future.     

Correlations between silt density index,turbidity and oxidation-reduction potential parameters in seawater reverse osmosis desalination

The reverse osmosis method is one of the most widely used methods of seawater desalination at present.Hydrophilic and desalting membranes in reverse osmosis systems are highly susceptible to the input pollutants.Various contaminants,including suspended organic and inorganic matter,result in membrane fouling and membrane degradation.Fundamental parameters such as the turbidity,the amount of chlorine injection,and silt density index(SDI)are the most predominant parameters of fouling control in the membranes.In this study,the operation system included a water intake unit,a pretreatment system,and an RO system.The pretreatment system encompassed a clarifier,a gravity sand filter,pressurized sand filters,and a cartridge filter.The correlation between the amount of chlorine injection in terms of the oxidation-reduction potential(ORP)and the SDI value of the input water was investigated at a specified site next to the Persian Gulf.The results showed that,at certain intervals of inlet turbidity,injection of a certain amount of chlorine into the raw water has a distinct effect on the decrease of SDI.     

Experimental and computational study of microfluidic flow‐focusing generation of gelatin methacrylate hydrogel droplets

This work presents the experimental and computational study of droplet generation for hydrogel prepolymer solution in oil using a flow‐focusing device. Effects of different parameters on hydrogel droplet generation and droplet sizes in a flow‐focusing device were investigated experimentally and computationally. First, three dimensional (3D) computational simulations were conducted to describe the physics of droplet formation in each regime and mechanism of three different regimes: squeezing, dripping, and jetting regime of hydrogel were investigated. Subsequently, the effects of viscosity, inertia force, and surface tension force on droplet generation, and droplet size were studied through these experiments. The experiments were carried out using different concentration of gelatin methacrylate (GelMA) hydrogel (5 wt % and 8 wt %) as the dispersed phase and two different continuous phase liquids (light mineral oil and hexadecane) with various concentrations of surfactant (0 wt %, 3 wt %, and 20 wt %). All experimental data was summarized by capillary number of dispersed phases and the continuous phases to characterize the different regimes of droplet generation and to predict the transition of dripping to a jetting regime for GelMA solution in flow‐focusing devices. It is shown that the transition of dripping to a jetting regime for GelMA happens at lower capillary numbers compared to aqueous solutions. Moreover, by increasing the viscous force of continuous phase or decreasing the interfacial force, the size of GelMA droplets was decreased. By controlling these parameters, the droplet sizes can be controlled between 30 μm and 200 μm, which are very suitable for cell encapsulation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43701.     

Electronic properties of graphyne nanotubes filled with small fullerenes: a density functional theory study

The encapsulation of small fullerenes into graphyne nanotubes was studied to investigate the possibility of band gap engineering in these nanotubes. The electronic properties of zigzag (4,0) and (5,0) graphyne nanotubes filled with small \(\hbox {C}_{20}\) and \(\hbox {C}_{30}\) fullerenes were studied using density functional theory. It was found that the zigzag (4,0) and (5,0) graphyne nanotubes were semiconductors. These graphyne nanotubes filled with \(\hbox {C}_{20}\) and \(\hbox {C}_{30}\) fullerenes were shown p-type and n-type semiconducting properties, respectively. The energy band gap was dependent on the number of the encapsulated fullerenes. Our results demonstrated the ability of band gap engineering through the encapsulation of small fullerenes into graphyne nanotubes.     

Group Decision Making and Perceived Decision Success: The Role of Communication Medium.

The authors investigated the role of communication medium on the relationship between team member perceptions and decision success. Seventy-three 3-person groups participated in a consensus intellective task either face-to-face (FTF) or via computer-mediated communication (CMC). The participants also assessed their group's decision success and team member competencies. CMC group members' success perceptions significantly predicted their group's performance, but FTF group members' perceptions did not. Furthermore, only CMC group members' judgments regarding their group's problem-solving ability significantly predicted their decision success. Last, judgments of decision success mediated the relationship between perceptions of members' problem-solving ability and decision success only for CMC group members. Implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microbial and "de novo" transformation of dicarboxylic acids by three airborne fungi

Micro-organisms and organic compounds of biogenic or anthropogenic origins are important constituents of atmospheric aerosols, which are involved in atmospheric processes and climate change. In order to investigate the role of fungi and their metabolisation activity, we collected airborne fungi using a biosampler in an urban location of Montreal, Quebec, Canada (45 degrees 28' N, 73 degrees 45' E). After isolation on Sabouraud dextrose agar, we exposed isolated colonies to dicarboxylic acids (C(2)-C(7)), a major group of organic aerosols and monitored their growth. Depending on the acid, total fungi numbers varied from 35 (oxalic acid) to 180 CFU/mL (glutaric acid). Transformation kinetics of malonic acid, presumably the most abundant dicarboxylic acid, at concentrations of 0.25 and 1.00 mM for isolated airborne fungi belonging to the genera Aspergillus, Penicillium, Eupenicillium, and Thysanophora with the fastest transformation rate are presented. The initial concentration was halved within 4.5 and 11.4 days. Other collected fungi did not show a significant degradation and the malonic acid concentration remained unchanged (0.25 and 1.00 mM) within 20 days. Degradation of acid with formation of metabolites was followed using high performance liquid chromatography-ultraviolet detection (HPLC/UV) and gas chromatography-mass spectrometry (GC/MS), as well as monitoring of (13)C labelled malonic acid degradation with solid-state nuclear magnetic resonance spectroscopy (NMR). Using GC/MS we identified two processes driving chemical modifications of organic aerosol solutions: (I) formation of metabolites within several days, and (II) rapid release (< or =2 min) of organic molecules from fungal species upon the insertion of taxa in organic aerosol solutions. Metabolites included aromatic compounds and alcohols (e.g. trimethylbenzene and butanol). Potential atmospheric implications of our results are discussed.     

Suspended mechanical structures based on elastic silicon nanowire arrays

We demonstrate a bottom-up/top-down combined method for the fabrication of horizontally suspended, well-oriented and size-controlled Si nanowire arrays. Mechanical beamlike structures composed of multiple ordered arrays consecutively linked by transversal microspacers are obtained by this method. Such structures are used to investigate the mechanical elasticity of the nanowire arrays by atomic force microscopy. Our results point out important differences in the morphology and mechanical behavior of the fabricated nanowire-based structures with respect to equivalent bulk material structures.     

Changes in essential oil and physiological parameters of callus and seedlings of <Emphasis Type="Italic">Carum copticum</Emphasis> L. under in vitro drought stress

Drought stress exerts a considerable influence on the production of secondary metabolites, which have interesting biological properties and quite a number are of medicinal importance, in plants. Secondary metabolites also are unique sources for food additives, flavors and industrially important biochemical. They play a major role in the adaptation of plants to the environment and overcoming stress conditions. This study was carried out to elucidate the mechanism of drought stress in seedlings and calli of Carum copticum under in vitro condition by evaluating the physiological and enzymatic activities, and secondary metabolites. Seedlings of C. copticum were cultured in MS medium containing 0, 3 and 6% mannitol and calli were cultured in MS medium containing 1 µM 2,4-d, 4 µM BAP and different levels of mannitol (0, 3 and 6%). After 4 weeks, the enzymatic and physiological parameters were measured by adapting spectrophotometrically and the GC/MS was used for the identification of secondary metabolites. Drought stress induced by mannitol caused a progressive increase of proline and carbohydrates contents in both seedlings and calli and the activation of CAT and SOD enzymes. In addition, drought stress effected the essential oil compounds of seedlings and callus. As compared to the control, mannitol enhanced the percentage of thymol in seedlings and callus under treatment (18.7 and 20.8%) and γ-terpinene (20.0 and 24.6%) as major components. In vitro drought stress induced by mannitol effected the biochemical, physiological and metabolic responses, suggesting that its beneficial effect can be exerted on the main essential oil contents.