Growth Actuated Bending and Twisting of Single Crystals

Crystals of a variety of substances including elements, minerals, simple salts, organic molecular crystals, and high polymers forgo long‐range translational order by twisting and bending as they grow. These deviations have been observed in crystals ranging in size from nanometers to centimeters. How and why so many materials choose dramatic non‐crystallographic distortions is analyzed, with an emphasis on crystal chemistries that give rise to stresses operating either on surfaces of crystallites or within the bulk.     

Hypervalent Iodine Oxidation of Hydrazones of Some Nitrogen Heterocyclic Ketones and Aldehydes: An Efficient Synthesis of Fused 1,2,3-Triazoloheterocycles

Fused 1,2,3-triazoloheterocycles have been prepared by iodobenzene diacetate mediated oxidation of hydrazones of nitrogen heterocyclic ketones and aldehydes.     

On multivariate calibration with unlabeled data

In principal component regression (PCR) and partial least‐squares regression (PLSR), the use of unlabeled data, in addition to labeled data, helps stabilize the latent subspaces in the calibration step, typically leading to a lower prediction error. For using unlabeled data in PLSR, a non‐sequential approach based on optimal filtering (OF) has been proposed in the literature. In this work, a sequential version of the OF‐based PLSR and a PCA‐based PLSR (PLSR applied to PCA‐preprocessed data) are proposed. It is shown analytically that the sequential version of the OF‐based PLSR is equivalent to that of PCA‐based PLSR, which leads to a new interpretation of OF. Simulated and experimental data sets are used to point out the usefulness and pitfalls of using unlabeled data. Unlabeled data can replace labeled data to some extent, thereby leading to an economic benefit. However, in the presence of drift, the use of unlabeled data can result in an increase in prediction error compared to that obtained with a model based on labeled data alone. Copyright © 2011 John Wiley & Sons, Ltd.     

A systematic family-wide investigation reveals that ~30% of mammalian PDZ domains engage in PDZ-PDZ interactions

PDZ domains are independently folded modules that typically mediate protein-protein interactions by binding to the C termini of their target proteins. However, in a few instances, PDZ domains have been reported to dimerize with other PDZ domains. To investigate this noncanonical-binding mode further, we used protein microarrays comprising virtually every mouse PDZ domain to systematically query all possible PDZ-PDZ pairs. We then used fluorescence polarization to retest and quantify interactions and coaffinity purification to test biophysically validated interactions in the context of their full-length proteins. Overall, we discovered 37 PDZ-PDZ interactions involving 46 PDZ domains (~30% of all PDZ domains tested), revealing that dimerization is a more frequently used binding mode than was previously appreciated. This suggests that many PDZ domains evolved to form multiprotein complexes by simultaneously interacting with more than one ligand.     

Standardization and validation of phytometabolites by UHPLC and high-performance thin layer chromatography for rapid quality assessment of ancient ayurvedic medicine,Mahayograj Guggul

Mahayograj Guggul is an ancient ayurvedic medicine, prescribed for various joint disorders like arthritis, gout, and rheumatism. The present research was envisaged to develop a simple, sensitive, and comprehensive analytical method for standardization of Mahayograj Guggul. The analysis was conducted for gallic acid, protocatechuic acid, vanillic acid, cinnamic acid, piperine, guggulsterone-E, and guggulsterone-Z by high-performance thin-layer chromatography, and additionally ferulic acid, ellagic acid, and picroside I by ultra high-performance liquid chromatography. These developed methods were validated as per international guidelines, and were found linear (r² > 0.99), sensitive, precise (relative standard deviation < 5%), and accurate with recovery values (85–105%). The limit of detection and quantification were in the range of 0.11–23.6 and 0.33–71.51 μg/g. Gas chromatography tandem mass spectrometry was used to develop Mahayograj Guggul fingerprinting profile and to identify mid-polar or nonpolar compounds. Proximate analysis was used to ascertain the functional groups present in Mahayograj Guggul. Ultra high-performance liquid chromatography and gas chromatography tandem mass spectrometry were further employed to authenticate quality reproducibility in the active ingredients of Mahayograj Guggul in six commercial batches. Taken together, these analytical methods provide a scientific basis and reference for quality control evaluation of Mahayograj Guggul and similar traditional broad-spectrum formulations.     

Family-wide Investigation of PDZ Domain-Mediated Protein-Protein Interactions Implicates β-Catenin in Maintaining the Integrity of Tight Junctions

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A possible method for measuring the rate of rotation of the plane of polarization of an ultrasonic wave passing through a metal

In this paper, we show that it should be possible to measure the rate of rotation of the plane of polarization of an ultrasonic wave passing through a sample with flat and parallel ends, by making detailed studies of the effects of such rotations on the mechanical resonances of the sample. The plane of polarization is expected to rotate, for example, when the sound wave is passing through pure metal single crystals in the presence of external magnetic fields. Measurements of such rotations can give useful information about the physical properties of the metal.     

Synthesis and Characterization of Unsymmetric 4-Picolyl Selenides

A number of unsymmetrical heteroaryl 4-picolyl selenides have been prepared by lithiation of 4-picoline using lithium diisopropylamide under cryogenic conditions. The intermediate 4-lithiopicoline formed was then reacted with elemental selenium followed by the addition of suitable electrophiles to give 4-picolyl alkyl selenides. 4-Lithiopicoline was also made to react directly with diaryl/dibenzyl diselenide to yield mixed 4-picolyl aryl/benzyl selenides. All these hitherto unknown selenides were characterized through various spectroscopic techniques viz., NMR (¹H, ¹³C, ⁷⁷Se), IR and mass spectrometry.