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Objectives/hypothesisTo test intratumoral photodynamic therapy (IPDT) as a new treatment for squamous cell carcinoma in a preclinical tumor model.Study design and methodsHuman P3 squamous carcinoma cells were transplanted subcutaneously in athymic nude mice and allowed to grow into 300- to 500-mm3 tumors. Hypericin dye at 1 microg/gm of body weight was injected intratumorally (IT) or intravenously (IV). After 4 hours hypericin biodistribution was assessed in ethanol extracts from tissues by fluorescence spectroscopy. IPDT also was tested by KTP laser fiberoptic insertion in tumors 4 hours after IT dye injection compared to KTP532 laser therapy alone (532 nm, 1W, 40-60 J, 0.6-mm fiber).ResultsHypericin concentration in tissues was as follows: (IT vs. IV) for tumors (3660 vs. 135 ng dye/gm tissue), lung (760 vs. 6345), liver (75 vs. 935), blood (65 vs. 480) compared to skin (465 vs. 110) or muscle (335 vs. 80) adjacent to the squamous cell tumors. Four hours after dye injection, the tumor exhibited bright orange fluorescence when excited by KTP 532-nm green laser light. The IPDT-treated tumors had a 3.32+/-0.32-mm radius of cell destruction when H&E-stained sections were examined compared with 2.5+/-0.38 mm for the laser only control group (n = 10, P = .003).ConclusionsThis pilot study indicates laser IPDT with hypericin induces a significant increase in tumor necrosis compared with laser alone and may be useful as a less invasive adjuvant treatment for recurrent or inoperable human squamous cell cancers of the head and neck.

Mass transfer limitations and kinetics studies were performed for Fischer-Tropsch Synthesis over spherical 10wt% Fe-10wt% Co-0.5wt% Pt/79.5wt% γ-Al2O3 catalyst in a fixed bed reactor. The external mass transfer limitation was checked by studying the effect of gas hourly space velocity (GHSV) and feed flow rate (at constant GHSV) on CO conversion. Theoretical and practical methods were applied to assess the effect of catalyst pellet size on the internal mass transfer limitation. The results indicated there is external diffusion limitation for GHSV lower than 4,200 h−1. Both the theoretical and practical methods showed that the reaction is free of internal diffusion limitation with average particle sizes of 0.21 and 0.42 mm due to Thiele modulus smaller than 0.4, denoting that the rate of reaction is kinetically controlled. The kinetics results demonstrated the combined enol and carbide mechanism-based model was able to provide a good fit for the experimental data. [ABSTRACT FROM AUTHOR]

Hybrid composites of polyethylene/wood flour/nanoclay with different concentrations of nanoclay were fabricated using melt compounding followed by injection molding. Composites were weathered in a xenon- arc type accelerated weathering apparatus for 2000 h. Physical properties of the composites were evaluated by colorimetery and water absorption before and after weathering. Changes in surface chemistry were monitored using spectroscopic techniques. The results indicated that water absorption of the composites increased after weathering, but nanoclay can reduce the intensity of weathering to some extent by decreasing water absorption. Weathering increased the degree of color change and lightness of the samples; however, the lightness of the samples containing nanoclay was less than that of neat wood-plastic composites. Fourier transform infrared spectroscopy revealed a lower carbonyl index of composites containing nanoclay. X-ray diffraction patterns revealed that the nanocomposites formed were intercalated. The order of intercalation for samples containing 2 wt% nanoclay was higher than that of 4 wt% at the same maleic anhydride grafted polyethylene content, due to some agglomeration of the nanoclay. [ABSTRACT FROM AUTHOR]