Multi‐responsive polymeric microcontainers for potential biomedical applications: synthesis and functionality evaluation

Temperature and pH responsive poly(N‐isopropylacrylamide‐co‐methacrylic acid) (P(NIPAAm‐co‐MAA)) microcontainers with encapsulated magnetic nanoparticles in the shell were prepared by a two‐stage distillation precipitation polymerization. PMAA@Fe₃O₄/P(NIPAAm‐co‐MAA) core–shell nanoparticles were synthesized by the second‐stage polymerization of NIPAAm, MAA and N, N′‐methylenebisacrylamide as crosslinker in the presence of magnetic nanoparticles and PMAA as core. These novel triple‐functional microcontainers were prepared by selective removal of the PMAA core in water. Daunorubicin hydrochloride (DNR) was loaded into the microcontainers and the release profile was studied by UV–visible spectroscopy. The synthesized nanostructures were characterized with transmission and scanning electron microscopy, X‐ray diffraction and Fourier transform infrared spectroscopy. The magnetic properties were evaluated by vibrating sample magnetometry. The shrink and swelling behavior was studied by dynamic light scattering. Copyright © 2012 Society of Chemical Industry     

The effect of basil (Ocimum basilicum L.) on soil organic matter biodegradation and other soil chemical properties

The effects of basil (Ocimum basilicum L.) on soil organic matter biodegradation, nutritional mineral elements and bacterial colonies were studied in the laboratory. The air‐dried basil plant tissues incorporated at five different rates (0, 1, 2, 3, and 4 g per 50 g of soil) resulted in increases in organic carbon mineralization, mineral nitrogen forms in organic phosphorus and available potassium. The level of available forms of manganese and zinc was increased at all the rates of added basil whereas copper was increased at the two upper rates. Also, the addition of basil resulted in a decrease in soil bacterial colonies. The results of this study indicated that the basil could be used as a cover crop for suppressing weed or pathogens in organic soils, with a positive effect on soil productivity. In addition, the incorporation of basil in soil could reduce the number of bacterial colonies. Copyright © 2007 Society of Chemical Industry     

Influence of salinity on lead and cadmium accumulation by the salt cedar (Tamarix smyrnensis Bunge)

BACKGROUND: The removal of heavy metals from polluted soils through the use of suitable plants has attracted much interest over recent decades. In this study Tamarix smyrnensis Bunge has been investigated for the characterization of its metal tolerance and ability to accumulate Pb and Cd, in order to evaluate its effectiveness as a cleanup tool for phytoextraction applications. For this purpose, two hydroponic experiments were performed, one with lead at concentration 100 ppm and a second with cadmium at concentration 5 ppm and at three different salt concentrations (0, 100, 200 mmol L^?1 NaCl). RESULTS: The experimental results showed that Pb and Cd accumulation in shoots ranged from 150–270 ppm and 7.5–42 ppm, respectively, and salinity was found to increase metal accumulation in shoots. However, the presence of high metal and salt concentrations affected negatively the health and finally the survival of the plants. CONCLUSION: T. smyrnensis is neither a Pb nor a Cd hyperaccumulator; however, metal accumulation levels in shoots considered together with its high biomass production suggest that it could be used for phytoextraction applications. Furthermore, salinity has a positive influence on Pb and Cd accumulation in harvestable parts of the plant when it remains in low concentrations. Copyright © 2009 Society of Chemical Industry     

Implementing Equitable Water Allocation in Transboundary Catchments: The Case of River Nestos/Mesta

Border areas comprise inevitably problematic fields especially when the countries are bound to share common water resources. The conflict potential is rather high and quite often countries are directed to the negotiation table in order to form tranboundary agreements. These agreements aim to the settlement of tensions and conflicts originating from the management of shared water resources. Often a starting point of the conflict resolution is the water allocation scheme between the interested parts. The definition of entitlements over shared water resources in not an easy task and it requires the use of specific decision tools in order to reach the maximum level of objectivity. According to the Water Framework Directive (WFD) 2000/60, management of transboundary catchments shall be based on existing structures set by international agreements, such as the UN Convention on the Protection and Use of Transboundary Watercourses and International Lakes. The main aim of this paper is the implementation of a water allocation tool based on representative indicators characterizing the involved parties while placing emphasis on environmental protection. The variables used are proposed by the UN Convention on the Law of the Non-navigational Uses of International Watercourses incorporating both natural and socio-economic aspects. These factors are quantified for each country and a weight factor is assigned to each one depending on its importance and suitability for describing the environmental and socio-economic situation in each country. As an illustration example the transboundary river Nestos/Mesta case is presented.     

Controlling Electrochemically Induced Volume Changes in Conjugated Polymers by Chemical Design: from Theory to Devices

Electrochemically induced volume changes in organic mixed ionic-electronic conductors (OMIECs) are particularly important for their use in dynamic microfiltration systems, biomedical machinery, and electronic devices. Although significant advances have been made to maximize the dimensional changes that can be accomplished by OMIECs, there is currently limited understanding of how changes in their molecular structures impact their underpinning fundamental processes and their performance in electronic devices. Herein, a series of ethylene glycol functionalized conjugated polymers is synthesized, and their electromechanical properties are evaluated through a combined approach of experimental measurements and molecular dynamics simulations. As demonstrated, alterations in the molecular structure of OMIECs impact numerous processes occurring during their electrochemical swelling, with sidechain length shortening decreasing the number of incorporated water molecules, reducing the generated void volumes and promoting the OMIECs to undergo different phase transitions. Ultimately, the impact of these combined molecular processes is assessed in organic electrochemical transistors, revealing that careful balancing of these phenomena is required to maximize device performance.     

Merging high doxorubicin loading with pronounced magnetic response and bio-repellent properties in hybrid drug nanocarriers

Hybrid magnetic drug nanocarriers are prepared via a self-assembly process of poly(methacrylic acid)-graft-poly(ethyleneglycol methacrylate) (p(MAA-g-EGMA)) on growing iron oxide nanocrystallites. The nanocarriers successfully merge together bio-repellent properties, pronounced magnetic response, and high loading capacity for the potent anticancer drug doxorubicin (adriamicin), in a manner not observed before in such hybrid colloids. High magnetic responses are accomplished by engineering the size of the magnetic nanocrystallites (～13.5 nm) following an aqueous single-ferrous precursor route, and through adjustment of the number of cores in each colloidal assembly. Complementing conventional magnetometry, the magnetic response of the nanocarriers is evaluated by magnetophoretic experiments providing insight into their internal organization and on their response to magnetic manipulation. The structural organization of the graft-copolymer, locked on the surface of the nanocrystallites, is further probed by small-angle neutron scattering on single-core colloids. Analysis showed that the MAA segments selectively populate the area around the magnetic nanocrystallites, while the poly(ethylene glycol)-grafted chains are arranged as protrusions, pointing towards the aqueous environment. These nanocarriers are screened at various pHs and in highly salted media by light scattering and electrokinetic measurements. According to the results, their stability is dramatically enhanced, as compared to uncoated nanocrystallites, owing to the presence of the external protective PEG canopy. The nanocarriers are also endowed with bio-repellent properties, as evidenced by stability assays using human blood plasma as the medium.     

Comparison of neem or oregano with thiram on organic matter decomposition of a sand loam soil amended with compost,and on soil biological activity

BACKGROUND: Oregano essential oil and neem have been reported to be effective against soil‐borne pathogens and nematodes. The possibility of having an effect on soil properties was the aim of this investigation. Moreover, thiram, a common widely used chemical pesticide, was used for comparison. RESULTS: The effects of all three above‐mentioned substances were investigated during an incubation experiment, for 15 weeks. Crushed neem pellets were added at 1.0, 2.0 or 3.0 g per 50 g of soil. Oregano dry matter was applied at 0.2, 0.4 or 0.6 g per 50 g of soil. Finally, thiram was applied at 0.1, 0.2 and 0.3 g per 50 g of soil. The addition of neem resulted in a decrease in organic carbon mineralisation, higher than that of oregano, but not as prominently as thiram. The addition of neem resulted in an increase in the content of nitrate, organic P, bioavailable P, bioavailable K and bioavailable Mn. Oregano had a slight negative effect on organic matter biodegradation, but caused an increase of nutritional mineral elements. Microbe colonies in soil were increased by the addition of neem cake granules, whereas oregano and thiram treatments caused a decrease. The addition of thiram reduced nitrate and available Mn contents, but at the lowest dose increased organic P and available K. Thiram reduced prominently available Cu at the upper rates, but it increased these forms at the lowest rate, while available Zn content was increased in two lowest rates. CONCLUSION: The results of this study indicated that neem or oregano could be applied to the soil without any extremely negative effect on the available forms of nutritional mineral elements, as thiram does. Copyright © 2009 Society of Chemical Industry     

Modeling oral reading fluency development in Latino students: A longitudinal study across second and third grade.

This study examines growth in oral reading fluency across 2nd and 3rd grade for Latino students grouped in 3 English proficiency levels: students receiving English as a second language (ESL) services (n = 2,182), students exited from ESL services (n = 965), and students never designated as needing services (n = 1,857). An important focus was to learn whether, within these 3 groups, proficiency levels and growth were reliably related to special education status. Using hierarchical linear modeling, the authors compared proficiency levels and growth in oral reading fluency in English between and within groups and then to state reading benchmarks. Findings indicate that oral reading fluency scores reliably distinguished between students with learning disabilities and typically developing students within each group (effect sizes ranging from 0.96 to 1.51). The growth trajectory included a significant quadratic trend (generally slowing over time). These findings support the effectiveness of using oral reading fluency in English to screen and monitor reading progress under Response to Intervention models, but also suggest caution in interpreting oral reading fluency data as part of the process in identifying students with learning disabilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)