Bio-optical inversion scheme based on the radiative transfer equation.

An inversion algorithm based on a forward optical model based on a radiative transfer equation is developed in terms of IOPs with explicit inclusion of the volume scattering function (VSF). Key results from the analysis are: 1) the inversion retrievals perform to comparable levels as the operational configuration of the NASA's Generalized Inherent Optical Property (GIOP) framework; 2) closure error between RT r and measured r have no significant effect on predicting the accuracy of the derived IOPs; and 3) $\tilde {b}_{bp}$ is important to ZTT, but not explicitly included in other types of comparable semi-analytic algorithms.

Modeling ocean surface chlorophyll-a concentration from ocean color remote sensing reflectance in global waters using machine learning.

The spatial and temporal variations of Chlorophyll-a (Chl-a) in clear and coastal waters are critical for assessing the health of the marine environment. Machine learning models have been proven to model complex relationships and provide better accuracy estimates of the derived parameters compared to traditional empirical models. The present study proposes a novel approach to derive Chl-a by using multi-layer perceptron Neural Network (MLPNN) with Resilient backpropagation method based on the four ocean color bands existent in most of the ocean color sensors.

Nickel-Catalyzed Annulations of -Haloarylimines.

We report the discovery, development, and mechanism of a nickel-catalyzed annulation reaction between -haloarylimines and electron-poor olefins. The reaction produces two adjacent stereocenters and a free secondary amine. Spirocycles are formed from cyclic imines.

Discovery of 3-(benzofuran-2-ylmethyl)-1H-indole derivatives as potential autophagy inducers in cervical cancer cells.

In this manuscript we have documented the identification of a novel anticancer scaffold 3-(benzofuran-2-ylmethyl)-1H-indole. This scaffold has been designed by tweaking the known bisindolylmethane scaffold of natural products that display a wide range of biological activities. A series of 24 new conjugates have been synthesized and among them 5 derivatives exhibited IC values less than 40 µM against two cervical cancer cell lines SiHa and C33a.

Ru(II)-Catalyzed C-H Activation/Alkylation of 3-Formylbenzofurans with Conjugated Olefins: Product Divergence.

Ru-catalyzed alkylation of 3-formylbenzofuran with acrylates and acrylamides has been described. Branched selectivity with unsubstituted or β-substituted acrylates/acrylamides and linear selectivity with α-substituted acrylates have been observed. However, in all of the cases, the intermediate alkylation products seem to undergo further reactions, either cycloannulation or deformylation, depending on the substrate employed.

Total Synthesis of Propolisbenzofuran B.

An efficient synthesis of propolisbenzofuran B, which possesses promising anticancer activity, is reported. The key cyclohexanone framework of this tricyclic natural product has been constructed employing a Rh-catalyzed intramolecular olefin hydroacylation. The requisite key olefin intermediate was synthesized by using gold-catalyzed allenyl ether [1,3] O → C rearrangement.

Interrupting Base-Mediated Benzofuran Ring Transformation with Michael Acceptors.

A simple two-stage approach for the synthesis of 3-(2-arylbenzofuran-3-yl)propanoates and propanamides has been developed employing simple acrylates and acrylamides and readily available 3-aroylbenzofurans. The key step of this process involves a base-mediated ring opening of the 3-aroylbenzofurans and subsequent Michael addition of the resulting 1,3-dicarbonyl intermediate with acrylate/acrylamide, followed by the deformylation in one-pot. The resulting products undergo an acid-mediated dehydrative cyclization to arrive at these targets.

Electronic Control on Linear versus Branched Alkylation of 2-/3-Aroylbenzofurans with Acrylates: Combined DFT and Synthetic Studies.

Investigations on the factors that govern unusual branched alkylation of 2-aroylbenzofurans with acrylates by Ru-catalyzed carbonyl-directed C-H activation has been carried out by calculating the kinetics associated with the two key steps-the coordination of the acrylate with the intermediate ruthenacycle and the subsequent migratory insertion reaction-studied with the help of DFT calculations. Eight possible orientations for each mode of alkylation have been considered for the calculations. From these calculations, it has been understood that there is a synergistic operation of the steric and electronic effects favoring the branched alkylation.

Ru-catalyzed branched versus linear selective C3-alkylation of 2-aroylbenzofurans with acrylates via C-H activation.

The carbonyl-directed C3-H activation and alkylation of 2-aroylbenzo[b]furans with acrylates occurs selectively either in a linear or branched fashion, depending on the catalyst employed; [Ru(p-cymene)Cl2]2 or Ru(PPh3)3Cl2, respectively. Two alternate pathways--funded upon the differences in steric and electronic preferences of these two complexes--is proposed for the selectivity of linear versus branched products.

Explaining cross-country variation in cigarette consumption.

This short paper uses cross-country data on per capita cigarette consumption and selected socio-economic variables to explain inter-country differentials in consumption. It is found that the proportion of the aged in the total population and higher literacy among women have relatively greater and positive impact on cigarette consumption. Even after controlling for the effect of the two variables, a country's industrialized status has a positive impact on consumption.