Evidence for the contribution of sulfur–bromine intramolecular interactions to the self-rigidification of thiophene-based π-conjugated systems

Bithiophene associating 3,4-ethylenedioxythiophene and 3-bromothiophene, and the corresponding polymer exhibit self-rigidified structures of the conjugated backbones resulting from the association of S–Br and S–O non-bonded intramolecular interactions

Tristhienylphenylamine - extended dithiafulvene hybrids as bifunctional electroactive species

Extended hybrid conjugated systems based on a trithienylphenylamine core with 1, 2 and 3 peripheral dithiafulvenyl units have been synthesized and studied by cyclic voltammetry and UV-Vis. absorption spectroscopy. Theoretical calculations have also been undergone. The behaviour of these derivatives which depends on the number of dithiafulvene moieties grafted of the central core is cleared up. One polymer, obtained from derivative 3 presents polyelectrochromic properties

Early Localization of Bronchogenic Carcinoma

The performance of a fluorescence imaging device was compared with conventional white-light bronchoscopy in 100 patients with lung cancer, 46 patients with resected stage I non-small cell lung cancer, 10 patients with head and neck cancer, and 67 volunteers who had smoked at least 1 pack of cigarettes per day for 25 years or more. Using differences in tissue autofluorescence between premalignant, malignant, and normal tissues, fluorescence bronchoscopy was found to detect significantly more areas with moderate/severe dysplasia or carcinoma in situ than conventional white-light bronchoscopy with a similar specificity. Multiple foci of dysplasia or cancer were found in 13–24% of these individuals. Fluorescence bronchoscopy may be an important adjunct to conventional bronchoscopic examination to improve our ability to detect and localize premalignant and early lung cancer lesions

Segregated anatomical input to sub-regions of the rodent superior colliculus associated with approach and defense

The superior colliculus (SC) is responsible for sensorimotor transformations required to direct gaze toward or away from unexpected, biologically salient events. Significant changes in the external world are signaled to SC through primary multisensory afferents, spatially organized according to a retinotopic topography. For animals, where an unexpected event could indicate the presence of either predator or prey, early decisions to approach or avoid are particularly important. Rodents’ ecology dictates predators are most often detected initially as movements in upper visual field (mapped in medial SC), while appetitive stimuli are normally found in lower visual field (mapped in lateral SC). Our purpose was to exploit this functional segregation to reveal neural sites that can bias or modulate initial approach or avoidance responses. Small injections of Fluoro-Gold were made into medial or lateral sub-regions of intermediate and deep layers of SC (SCm/SCl). A remarkable segregation of input to these two functionally defined areas was found. (i) There were structures that projected only to SCm (e.g., specific cortical areas, lateral geniculate and suprageniculate thalamic nuclei, ventromedial and premammillary hypothalamic nuclei, and several brainstem areas) or SCl (e.g., primary somatosensory cortex representing upper body parts and vibrissae and parvicellular reticular nucleus in the brainstem). (ii) Other structures projected to both SCm and SCl but from topographically segregated populations of neurons (e.g., zona incerta and substantia nigra pars reticulata). (iii) There were a few brainstem areas in which retrogradely labeled neurons were spatially overlapping (e.g., pedunculopontine nucleus and locus coeruleus). These results indicate significantly more structures across the rat neuraxis are in a position to modulate defense responses evoked from SCm, and that neural mechanisms modulating SC-mediated defense or appetitive behavior are almost entirely segregated

Rigid oligomers based on the combination of 3,6-dimethoxythieno[3,2-b]thiophene and 3,4-ethylenedioxythiophene

New oligomers based on the combination of the 3,6-dimethoxythieno[3,2-b]thiophene and 3,4-ethylenedioxythiophene (EDOT) moieties have been prepared and studied by UV–vis spectroscopy and cyclic voltammetry. The use of the intrinsically rigid thienothiophene units in addition to the S⋯O intramolecular interactions leads to planar conformation of the conjugated chains. While the radical cations of oligomers end capped by n-hexyl chains show a tendency to the dimerization, those substituted by n-hexylsulfanyl chains present a high stability

Facile synthesis of 3-substituted thieno[3,2-b]furan derivatives

A facile synthesis of dimethyl 3-hydroxythieno[3,2-b]furan-2,5-dicarboxylate is reported from the available methyl thioglycolate and dimethyl acetylenedicarboxylate starting materials. This compound represents an efficient precursor for the synthesis of 3-substituted thieno[3,2-b]furan derivatives

Microbiology and atmospheric processes: chemical interactions of primary biological aerosols

This paper discusses the influence of primary biological aerosols (PBA) on atmospheric chemistry and vice versa through microbiological and chemical properties and processes. Several studies have shown that PBA represent a significant fraction of air particulate matter and hence affect the microstructure and water uptake of aerosol particles. Moreover, airborne micro-organisms, namely fungal spores and bacteria, can transform chemical constituents of the atmosphere by metabolic activity. Recent studies have emphasized the viability of bacteria and metabolic degradation of organic substances in cloud water. On the other hand, the viability and metabolic activity of airborne micro-organisms depend strongly on physical and chemical atmospheric parameters such as temperature, pressure, radiation, pH value and nutrient concentrations. In spite of recent advances, however, our knowledge of the microbiological and chemical interactions of PBA in the atmosphere is rather limited. Further targeted investigations combining laboratory experiments, field measurements, and modelling studies will be required to characterize the chemical feedbacks, microbiological activities at the air/snow/water interface supplied to the atmosphere

Star-shaped conjugated systems derived from dithiafulvenyl-derivatized triphenylamines as active materials for organic solar cells

Hybrid conjugated systems consisting of a triphenylamine core substituted by three dithiafulvenyl moieties have been synthesized and tested as active materials in organic field-effect transistors and photovoltaic devices. UV–vis. spectroscopy studies demonstrate that, despite their amorphous character shown by X-ray diffraction and differential scanning calorimetry, strong interactions exist in these materials as an aggregative band is observed at low energies. A first evaluation of their potentialities as p semiconductor in organic field-effect transistors shows significant hole mobilities. For bilayer photovoltaic devices, a power conversion efficiency of 0.11% is observed and the external quantum efficiency of the cell under monochromatic irradiation shows a non-negligible contribution of the aggregative band