Noninvasive assessment of cutaneous alterations in mice exposed to whole body gamma irradiation using optical imaging techniques

We report the results of a study carried out to investigate the potential of optical techniques such as optical coherence tomography, Mueller matrix spectroscopy, and cross-polarization imaging for noninvasive monitoring of the ionizing radiation exposure-induced alterations in cutaneous tissue of mice. Radiation dose-dependent changes were observed in tissue microvasculature and tissue optical parameters like retardance and depolarization as early as 1 h post radiation exposure. Results suggest that these optical techniques may allow early detection of radiation dose-dependent alterations which could help in screening of population exposed to radiation.

Chronic exposure to neonicotinoids reduces honey bee health near corn crops

Experiments linking neonicotinoids and declining bee health have been criticized for not simulating realistic exposure. Here we quantified the duration and magnitude of neonicotinoid exposure in Canada’s corn-growing regions and used these data to design realistic experiments to investigate the effect of such insecticides on honey bees. Colonies near corn were naturally exposed to neonicotinoids for up to 4 months—the majority of the honey bee’s active season. Realistic experiments showed that neonicotinoids increased worker mortality and were associated with declines in social immunity and increased queenlessness over time. We also discovered that the acute toxicity of neonicotinoids to honey bees doubles in the presence of a commonly encountered fungicide. Our work demonstrates that field-realistic exposure to neonicotinoids can reduce honey bee health in corn-growing regions.

Polyimides Containing an s-Triazine Ring

A series of new polyimides containing an s-triazine nucleus were prepared via Diels–Alder (DA) intermolecular polymerization of 2,6-bis(2-furanyl methyl imino)-4-ethoxy-1,3,5-triazine with different bis(maleimide) compounds. The DA reaction was carried out in tetrahydrofuran as solvent, as well as in bulk followed by aromatization of poly(tetrahydrophthalimido)-intermediates in the presence of acetic anhydride. All the poly(imino- s-triazine imide)s were characterized by elemental analysis, IR spectral studies and thermogravimetry. Glass fibre reinforced composites were prepared via in situ Diels–Alder intermolecular reaction between 2,6-bis(2-furanyl methyl imino)-4-ethoxy-1,3,5-triazine and different bis(maleimide) compounds without evolution of by-products. The prepared composites were characterized by chemical resistivity and mechanical properties.

Kinetic Studies on Epoxy Resins Cured with a Novel Polyamine

Differential scanning calorimeny was used to study the cure kinetics of three epoxy resin systems cured with two hardeners: diaminodiphenylmethane (DDM) and a poly (keto-amine) (PA). The results showved that the curing of the epoxy resins by PA occurs at higher temperatures and the activation energy for PA curing was higher compared with the DDM curing process, showing the er reactivity of PA.

Azo Dyes Based on Phenolic Oligomers: Acid Azo-Naphthol-Formaldehyde Oligomeric Dyes

A series of new oligomeric acid azo dyes were prepared by coupling various aromatic diazonium salts to 1-naphthol-formaldehyde and 2-naphthol-formaldehyde oligomers. They were characteried in terms of their softening points, yields, colour, solubility and UV-vis spectral studies. The structure-property relationships were also established. Dyeing of Nylon-6,6 and wool was also investigated. The dyeing of Nylon-6,6 and wool resulted in orange, brown to red and blue shades with excellent light fastness and washing fastness properties.

Effect of gold nanoparticles on depolarization characteristics of Intralipid tissue phantom

We report results of studies on the effect of different shapes and sizes of gold nanoparticles (GNPs) on the depolarization characteristics of Intralipid tissue phantoms. For a given extinction coefficient, the absorption characteristics of the GNPs contributed more to the depolarization of the turbid medium, and the contribution of scattering was significant only for the larger-sized particles. For rod-shaped GNPs, their depolarization plays an important role in the low scattering regime in which the depolarization properties of the nanoparticles (NPs) dominate in the turbid medium even if the contribution of the scattering from the NPs is about an order of magnitude less. For highly scattering samples, GNP absorption significantly modulates the depolarization spectra of the turbid medium.

Human papillomavirus infection and anal dysplasia in renal transplant recipients

BACKGROUND

Immunosuppression is a known risk factor for anal human papillomavirus (HPV) disease, including anal squamous cell carcinoma. Additional risk factors for HPV-related disease have not been studied in the renal transplant population. The demographics of anal HPV and associated risk factors were investigated in this population.

METHODS

Anal cytology and polymerase chain reaction were used to assess anal HPV disease in a cohort of transplant recipients at the Royal London Hospital. Risk factors associated with increased immunosuppression and HPV exposure were collated to determine any association with anal disease.

RESULTS

Anal dysplasia was associated with anal oncogenic HPV infection (P < 0.001), duration of immunosuppression (P = 0.050), previous genital warts (P = 0.018) and receptive anal intercourse (P = 0.013).

CONCLUSION

Anal dysplasia was related to immunosuppression and patient factors in this cohort.

Novel Fe (III) heterochelates: synthesis, structural features and fluorescence studies

Fluorescence properties of five 4-acyl pyrazolone based hydrazides (H(2)SB(n)) and their Fe (III) heterochelates of the type [Fe(SB(n))(L)(H(2)O)].mH(2)O [H(2)SB(n)=nicotinic acid [1-(3-methyl-5-oxo-1-phenyl-4,5-di hydro-1H-pyrazol-4yl)-acylidene]-hydrazide; where acyl=-CH(3), m=4 (H(2)SB(1)); -C(6)H(5), m=2 (H(2)SB(2)); -CH(2)-CH(3), m=3 (H(2)SB(3)); -CH(2)-CH(2)-CH(3), m=1.5 (H(2)SB(4)); -CH(2)-C(6)H(5), m=1.5 (H(2)SB(5)) and HL=1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid] were studied at room temperature. The fluorescence spectra of heterochelates show red shift, which may be due to the chelation by the ligands to the metal ion. It enhances ligand ability to accept electrons and decreases the electron transition energy. The kinetic parameters such as order of reaction (n), energy of activation (E(a)), entropy (S*), pre-exponential factor (A), enthalpy (H*) and Gibbs free energy (G*) have been reported.

Hydrogen Bonding Properties of Coumarin 151, 500, and 35: The Effect of Substitution at the 7-Amino Position

The steady-state spectral properties (absorption and emission) of three structurally similar Coumarin dyes, C151, C500, and C35 were investigated in 13 different solvents. A Kamlet-Taft (KT) analysis of the spectral peak frequencies reveals that, in addition to polarity, hydrogen bonding between the carbonyl oxygen and a protic solvent in the excited state imparts maximum stabilization for C151 and minimum for C35, while that for C500 lies in between. The spectral properties of the three dyes in two solvents, chloroform and THF, which have similar polarity in the KT scale but have only hydrogen-bond donor (chloroform) and hydrogen-bond acceptor (THF) properties, are seen to be sensitive to the substitution pattern at the 7-amino position. In addition, a slow emission spectral relaxation is observed for C151 and C500 having a time constant of approximately 500 ps in chloroform. For C35 this was too fast to be detected by the time resolution of our setup. The exact reason for this slow spectral relaxation in chloroform is unclear at present, and further studies are needed to understand clearly the structural effects on the hydrogen bonding dynamics of these dyes.

Depth-resolved fluorescence measurement in a layered turbid medium by polarized fluorescence spectroscopy

We show that, when a turbid medium with a layered fluorophore distribution is excited by linearly polarized light, measurement of angle-resolved polarized fluorescence can provide depth-resolved fluorescence measurements.

Increased dermal lymphatic density in the human leg compared with the forearm

During orthostasis, capillary filtration pressure is higher in the leg than in the arm due to the effect of gravity. We investigated the possibility that the lymphatic network in leg skin might be adapted to cope with a greater fluid load. The dermal lymphatics of the forearm and lower leg were studied in white-skinned and brown-skinned men using fluorescence video microscopy. From video print lymphangiograms the following were determined: lymphatic length density at a series of radii from the centre of the lymphangiogram (LDr); maximum lymphatic density (LDmax); total length of lymphatic vessel (LL); maximum spread of lymphatic vessel; number and size of lymphatic rings (continuous circuits of vessel); and vessel diameter. There were no differences between the two racial types, but clear differences between the arm and leg. In the leg, mean (+/- SD) peak LDr (25.13 +/- 5.65 cm-1), LDmax (32.95 +/- 6.89 cm-1), LL (40.17 +/- 27.42 cm), and spread (1.39 +/- 0.08 cm) were all significantly higher than in the arm (18.03 +/- 5.48 cm-1, 23.91 +/- 7.21 cm-1, 11.76 +/- 5.47 cm, and 1.00 +/- 0.05 cm respectively, P </= 0.001). In the region of maximum lymphatic density there were 2.4 times more rings in the leg than in the arm, ring size being similar. Vessel image diameters were 89.6 +/- 26.3 micron (leg) and 94.8 +/- 10.9 micron (arm). Leg skin thus has a denser and more extensive lymphatic network than arm skin. This supports the hypothesis that lymph transport capacity in the leg is enhanced to compensate for a greater gravitational fluid loading.