Experimental Methods for Measuring Optical Rotatory Dispersion:Survey and Outlook

The measurement of optical rotation (OR) and optical rotatory dispersion has been finding renewed interest for some years, because of advancement in computational methods and in the performance of new experiments. Here, we shortly review the traditional and most-used experimental methods. We define and discuss the two main types of approaches in measuring OR: the intensity method and the optical null method. We report on some new results obtained by redesigning experiments based on the first approach, by adapting nonsophisticated hardware to current circular dichroism instrumentation

NIR-VCD, vibrational circular dichroism in the near-infrared: Experiments, theory and calculations

The first well documented experiments of Near Infrared Vibrational Circular Dichroism (NIR-VCD) were performed around 1975. We review the thirty year history of NIR-VCD, encompassing both instrumental development and theoretical/computational methods that allow interpretation of experimental spectra, harvesting useful structural information therefrom. We hope to stimulate interest in this still scarcely explored spectroscopy of chiral molecule

Bullous lung disease and neurofibromatosis type-1.

Lung interstitial diseases and bullae are described as possible complications of neurofibromatosis type-1 (NF-1), a genetic disorder inherited as a autosomal-dominant trait. We report the case of a 16-year-old male non-smoker with NF-1, who presented with pneumothorax caused by ruptured lung bullae. The case of this young patient, successfully treated by video-assisted thoracoscopic resection of bullae, supports the concept that pulmonary alterations may be part of the NF-1 syndrome, rather than as an unrelated complication

Harmonic and Anharmonic Features of IR and NIR Absorption and VCD Spectra of Chiral 4-X-[2.2]Paracyclophanes

The vibrational absorption spectra and vibrational circular dichroism (VCD) spectra of both enantiomers of 4-X-[2.2]paracyclophanes (X ) COOCD3, Cl, I) have been recorded for a few regions in the range of 900- 12000 cm-1. The analysis of the VCD spectra for the two IR regions, 900-1600 cm-1 and 2800-3200 cm-1, is conducted by comparing with DFT calculations of the corresponding spectra; the latter region reveals common motifs of vibrational modes for the three molecules for aliphatic CH stretching fundamentals, whereas in the mid-IR region, one is able to identify specific signatures arising from the substituent groups X. In the CH stretching region between 2900 and 2800 cm-1, we identify and interpret a group of three IR VCD bands due to HCH bending overtone transitions in Fermi resonance with CH stretching fundamental transitions. The analysis of the NIR region between 8000 and 9000 cm-1 for X ) COOCD3 reveals important features of the aromatic CH stretching overtones that are of value since the aromatic CH stretching fundamentals are almost silent. The intensifying of such overtones is attributed to electrical anharmonicity terms, which are evaluated here by ab initio methods and compared with literature data

A comparative study of overtone CH- stretching vibrational circular dichroism spectra of fenchone and camphor

Near-infrared vibrational circular dichroism (VCD) spectra in the region 1500-850 nm are recorded for both enantiomers of camphor and fenchone using a home-built dispersive instrument. Two CH-stretching overtone regions and two CH-stretching/HCH-bending combination regions are investigated. The near-infrared VCD data are examined and compared with the corresponding previously published data of (3R)-(+)-methylcyclopentanone and (3R)-(+)-methylcyclohexanone. The absorption spectra of both the fundamental and overtone regions are also considered, and the fundamental CH-stretching VCD data are taken into account, where possible. An empirical assignment of the spectra is first considered, with special regard to the second CHstretching overtone region. This region is then investigated by a heuristic approach based on DFT calculations, using the hybrid functional B3LYP at the 6-31G** basis set level. Subsequently rotational strengths have been evaluated by use of a classical model based on the contribution of polarizable groups to the optical activity. The same models are also used to interpret the VCD spectra between 2000 and 3000 wavenumbers for (3R)-(+)-methylcyclopentanone-d4

Chromosomal assignment of the ovine hairless (hr) gene by fluorescence in situ hybridization.

Congenital hypotrichosis in mammalian species consists of partial or complete absence of a hair coat at birth. Affected individuals having a partial hair coat at birth may loose it subsequently.The aim of this paper was to physically map the ovine hr gene using fluorescence in situ hybridization (FISH).A preliminary study on an internet data bank (http://www.informatics.jax.org) showed that the regions of the hr gene on murine chromosome 14 and human chromosome 8 present homology with ovine chromosome 2

Absorption flattening as one cause of distortion of circular dichroism spectra of Delta-RuPhen(3) . H(2)TPPS complex

To extend the model that explains why and how much absorption flattening (AF) influences circular dichroism (CD) signals, we have investigated the interesting case of exciton CD in the Soret region of a noncovalent complex formed by (DRuPhen3) 21 and the tetraanionic porphyrin H2TPPS. Different concentrations have been studied by using an AF emulator and spectra simulation. The CD spectra of this compound occasionally show distortions in the solution sampling mode with the increase of concentration; the inhomogeneous distribution in the cell volume is due to aggregation and is the source of the AF effect. On the basis of these results, we conclude that AF is an important cause of distortions in CD spectra for D-RuPhen3 H2TPPS complexes and might affect the CD bands of other aggregated systems as wel

Synthesis and Biological Evaluation (in Vitro and in Vivo) of Cyclic RGD Peptidomimetic - Paclitaxel Conjugates Targeting Integrin alphaVbeta3

A small library of integrin ligand - Paclitaxel conjugates 10-13 was synthesized with the aim of using the tumor-homing cyclo[DKP-RGD] peptidomimetics for site-directed delivery of the cytotoxic drug. All the Paclitaxel-RGD constructs 10-13 inhibited biotinylated vitronectin binding to the purified alphaVbeta3 integrin receptor at low nanomolar concentration and showed in vitro cytotoxic activity against a panel of human tumor cell lines similar to that of Paclitaxel. Among the cell lines, the cisplatin-resistant IGROV-1/Pt1 cells expressed high levels of integrin alphaVbeta3, making them attractive to be tested in in vivo models. Cyclo[DKP-f3-RGD]-PTX 11 displayed sufficient stability in physiological solution and in both human and murine plasma to be a good candidate for in vivo testing. In tumor-targeting experiments against the IGROV-1/Pt1 human ovarian carcinoma xenotransplanted in nude mice, compound 11 exhibited a superior activity than Paclitaxel, despite the lower (ca. half) molar dosage used

Study of suitability of Fricke-gel-layer dosimeters for in-air measurements to characterize epithermal/thermal neutron beams for NCT

The reliability of Fricke gel dosimeters in form of layers for measurements aimed at the characterization of epithermal neutron beams has been studied. By means of dosimeters of different isotopic composition (standard, containing 10B or prepared with heavy water) placed against the collimator exit, the spatial distribution of gamma and fast neutron doses and of thermal neutron fluence are attained. In order to investigate the accuracy of the results obtained with in-air measurements, suitable MC simulations have been developed and experimental measurements have been performed utilizing Fricke gel dosimeters, thermoluminescence detectors and activation foils. The studies were related to the epithermal beam designed for BNCT irradiations at the research reactor LVR-15 (Řež). The results of calculation and measurements have revealed good consistency of gamma dose and fast neutron 2D distributions obtained with gel dosimeters in form of layers. In contrast, noticeable modification of thermal neutron fluence is caused by the neutron moderation produced by the dosimeter material. Fricke gel dosimeters in thin cylinders, with diameter not greater than 3 mm, have proved to give good results for thermal neutron profiling. For greater accuracy of all results, a better knowledge of the dependence of gel dosimeter sensitivity on radiation LET is needed