Time, space, and spectrally resolved studies on J-aggregate interactions in zeolite L nanochannels

Temporally and spectrally resolved confocal microscopy has been used to explore the behavior of pyronine intercalated zeolite L crystals at different loadings. The low pyronine loading of 0.6% exhibits photophysical behavior similar to that of the free molecule in solution, indicating molecules are isolated from each other in the crystal channels. The higher loading of 20% results in a dye gradient along the channel axis, and the presence of an additional red-shifted spectroscopic transition, with shorter lifetimes. The new band is assigned to an inline arrangement of the molecules undergoing a J-aggregate-type coupling, a process so far not observed in subnanometer channels.     

Enantioselective synthesis of BMS-911278: a triple reuptake inhibitor

BMS-911278 was identified as a potent triple reuptake inhibitor potentially useful for the treatment of depression. The original racemic synthesis suffered from tedious and low recovery resolution and HPLC separation, as well as low-yielding hazardous N-demethylation at the API step. To support further preclinical studies, a scalable enantioselective synthesis was developed. Herein, we report an efficient asymmetric synthesis of BMS-911278 featuring two key steps: an enantioselective Miyaura reaction and an intramolecular regioselective cyclization.     

Model-oriented ocean tomography using higher frequency, bottom-mounted hydrophones

A tomographic scheme is presented that ingests ocean acoustic measurements into an ocean model using data from bottom-mounted hydrophones. The short distances between source-receiver pairs (1-10 km) means arrival times at frequencies of 8-11 kHz are readily detectable and often distinguishable. The influence of ocean surface motion causes considerable variability in acoustic travel times. Techniques are presented for measuring travel times and removing the variability due to surface waves. An assimilation technique is investigated that uses differences in measured and modeled acoustic travel times to impose corrections on the oceanographic model. Equations relating travel time differences to oceanographic variables are derived, and techniques are presented for estimating the acoustic and ocean model error covariance matrices. One test case using a single source-receiver pair shows that the tomographic information can have an impact on constraining the solution of the ocean circulation model but can also introduce biases in the predictions. A second test case utilizes knowledge of a bias in a model-predicted variable to limit grid cells that are impacted by the tomographic data. In this case, using the tomographic data results in significant improvements in the model predictions without introducing any biases.     

Flow-induced transverse electrical potential across an assembly of gold nanoparticles

We report the generation of a potential difference, of the order of tens of millivolts, induced by the flow of polar liquids over an assembly of gold nanoparticles. The device consisted of two conducting glass plates, one of which contained the gold nanoparticle multilayer assembly. The potential generated is in transverse direction to the flow and is dependent on the nature of the flowing liquid. We propose a simple theoretical model to account qualitatively for the generation of the flow-induced transverse potential.     

Synthesis and characterization of an adipic acid–derived epoxy resin

Adipic acid, a highly abundant chemical that can be produced from biomass, was used to prepare an aromatic‐free epoxy resin. Synthesis of the diglycidyl adipate was performed by a one‐step process using epichlorohydrin and by a two‐step process comprising allylation and epoxidation. The viscosity of diglycidyl adipate is 25 mPa·s, which is 99% lower than the diglycidyl ether of bisphenol A (DGEBA). The storage modulus at 25 °C for cured diglycidyl adipate and DGEBA is 2000 and 3200 MPa, respectively. The alpha transition temperature through peak of the loss modulus and the peak of tan(δ), are 77 °C and 90 °C, respectively. Low‐viscosity epoxy applications are discussed herein. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2625–2631     

Green-synthesised nanoparticles from Melia azedarach seeds and the cyclopoid crustacean Cyclops vernalis: an eco-friendly route to control the malaria vector Anopheles stephensi?

The impact of green-synthesised mosquitocidal nanoparticles on non-target aquatic predators is poorly studied. In this research, we proposed a single-step method to synthesise silver nanoparticles (Ag NP) using the seed extract of Melia azedarach. Ag NP were characterised using a variety of biophysical methods, including UV–vis spectrophotometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. In laboratory assays on Anopheles stephensi, Ag NP showed LC₅₀ ranging from 2.897 (I instar larvae) to 14.548 ppm (pupae). In the field, the application of Ag NP (10 × LC₅₀) lead to complete elimination of larval populations after 72 h. The application of Ag NP in the aquatic environment did not show negative adverse effects on predatory efficiency of the mosquito natural enemy Cyclops vernalis. Overall, this study highlights the concrete possibility to employ M. azedarach-synthesised Ag NP on young instars of malaria vectors.     

Synthesis and electrical conductivity of polymers containing trans-1,2-bis(9-carbazolyl)cyclobutane units

Novel poly-Schiff bases (PSB's) that contain trans-1,2-bis(9-carbazolyl)cyclobutane(DCZB) units were synthesized by the direct polycondensation of trans-1,2-bis(3-formyl-9-carbazolyl)cyclobutane with aromatic diamines in n-amyl alcohol at 160°C. Complexation of these PSB's and of poly(vinyl DCZB) (PVDCZB) with iodine produced cation-radical salts which resulted form the transfer of an electron from DCZB moieties to iodine. All the undoped polymers were insulators having electrical conductivity of the order of 10^?10–10^?12 S cm^?1 depending on the structure of polymers. By doping with iodine, the electrical conductivity increased by several orders of magnitude and reached a value of 10^?3 S cm^?1 in the case of PVDCZB and 10^?5–10^?6 S cm^?1 in the case of PSB's. The electrical conductivity of doped PSB's increased with decreasing diamine length. PVDCZB having the same iodine content per carbazole unit as poly(9-vinyl-carbazole) (PVK) has a greater electrical conductivity than PVK.