The radial variation of void fraction in randomly packed beds of spheres, cylinders, Raschig rings, and Berl saddles was investigated. After packing, the beds were filled with parallln, which was then allowed to solidify. Slabs were cut from the bed, and annular rings were removed by two different experimental techniques. An analysis of experimental error revealed that reproducibility, for the sample size used, between different parts of the same bed and different beds was quite good.For highly irregular shapes such as Berl saddles results indicate that the void fraction decreases regularly from one at the wall to the average porosity at about 1 particle radius from the wall. This is in agreement with work of other investigators using irregularly shaped packings; most commercial packings would probably fit in this category.For regularly shaped particles results are quite different. For spheres and cylinders cycling was observed for more than 2 particle diam. into the bed, the amplitude decreasing as distance from the wall was increased. The maxima and minima were observed at integral multiples of the particle radius. For Raschig rings a hump was observed at about 1/2 particle radius from the wall. The void fraction then decreased to its average value at 1 particle radius and then remained constant.

Peptides and biologics provide unique opportunities to modulate intracellular targets not druggable by conventional small molecules. Most peptides and biologics are fused with cationic uptake moieties or formulated into nanoparticles to facilitate delivery, but these systems typically lack potency due to low uptake and/or entrapment and degradation in endolysosomal compartments. Because most delivery reagents comprise cationic lipids or polymers, there is a lack of reagents specifically optimized to deliver cationic cargo. Herein, we demonstrate the utility of the cytocompatible polymer poly(propylacrylic acid) (PPAA) to potentiate intracellular delivery of cationic biomacromolecules and nano-formulations. This approach demonstrates superior efficacy over all marketed peptide delivery reagents and enhances delivery of nucleic acids and gene editing ribonucleoproteins (RNPs) formulated with both commercially-available and our own custom-synthesized cationic polymer delivery reagents. These results demonstrate the broad potential of PPAA to serve as a platform reagent for the intracellular delivery of cationic cargo.

Previous work on the hydrocracking and hydroisomerization of alkanes over metal-impregnated anion-modified zirconium oxides (AZOs) is extended to long-chain alkanes, from n-heptane to high molecular weight polyolefins, using ZrO2 modified by anion-derived groups such as SO4 and WO3 and promoted with hydrogenation metals such as Pt or Ni. Depending on reaction temperature and time, high yields of C5−C12 isoalkanes or a mixture of gases with high selectivities to isobutane and isopentane can be produced. The products do not contain olefins, aromatics, or alkanes of carbon number higher than the feed. The iso/normal ratios of the alkane products obtained are significantly higher than those predicted by isomerization equilibria at the reaction conditions. It appears that higher (C7+) alkane hydrocracking over metal-promoted AZOs may not proceed via the conventional bifunctional mechanism involving initial dehydrogenation to an olefinic intermediate. The AZOs did not sinter or agglomerate during the hydrocracking reactions as indicated by particle size measurements. AZOs containing WO3 are more stable than those containing SO4, retaining their anionic groups in reactions at severe reducing conditions [300+ °C, 500−1200 psig (cold) H2]. XANES analysis of the Pt/ZrO2/WO3 catalyst indicated that both Pt and W maintained their zerovalent (Pt0) and hexavalent (W6+) states, respectively, during alkane hydrocracking as well as during recalcination in air.

With the growing importance of optical techniques in medical diagnosis and treatment, there exists a pressing need to develop and optimize materials platform for biophotonic applications. Particularly, the design of biocompatible and biodegradable materials with desired optical, mechanical, chemical, and biological properties is required to enable clinically relevant biophotonic devices for translating in vitro optical techniques into in situ and in vivo use. This technological trend propels the development of natural and synthetic polymeric biomaterials to replace traditional brittle, nondegradable silica glass based optical materials. In this review, we present an overview of the advances in polymeric optical material development, optical device design and fabrication techniques, and the accompanying applications to imaging, sensing and phototherapy.

The physicochemical properties and catalytic activities of an intriguing class of compounds based on iron and tin oxides treated with varying amounts of sulfate anion and employed for the direct liquefaction of three Argonne coals of varying ranks are reported in this paper. The sulfated transition-metal oxides have become a topic of interest partly because of their unusual properties, one of these being their so called "superacidity". The physicochemical properties of the sulfated oxides before reaction as determined by BET, XRD, TGA/DTA, SEM/TEM, and the types of active phases formed under liquefaction conditions as determined by XRD, STEM, EXAFS, and Mossbauer spectroscopy are correlated with their apparent activities for hydrocracking of coal. The sulfated iron oxide, Fe203/S042-was found to be an effective catalyst for coal liquefaction when used in small concentrations (<0.4 wt % iron); its use resulted in an 86 wt % (maf basis) conversion of Illinois No. 6 coal at 400 °C and 1000 psig of hydrogen (initial) with more than 50 wt % of the products consisting of oils (n-pentane solubles). Addition of elemental sulfur to the same catalyst (at 0.35 wt % Fe) enhanced the overall conversion to 90.3 wt % with more than 60% of products consisting of oils. Similar results for coal conversion were obtained for a solid superacid catalyst made from tin, Sn02/S042-, in the presence of sulfur. These conversions were considerably higher than those obtained in a thermal run under the same reaction conditions (% conversion = 62, wt % oils = 28). For both iron and tin oxides, their sulfated forms containing between 1.5 and 6 wt % of S042-groups were more active than their respective unsulfated forms. Significant hydrodenitrogenation (>70%) and hydrodesulfurization (>90%) were obtained with the sulfated metal oxide catalysts. Very small amounts of nitrogen (<0.5 wt %) and sulfur (<0.28 wt %) were found in the methylene chloride soluble products obtained from the liquefaction runs. The effects of the sulfate group in these oxides are likely due to an increase in catalyst dispersion; their superacidity may play a part or some other mechanism (radical ions) may be involved. The sulfate group probably inhibits agglomeration of the metal oxide catalysts at high temperatures.

We have recently reported on the catalytic activity of sulfated iron and tin oxides for the direct liquefaction of coal (Energy Fuels 1991, 5, 497-507) and on the activity of the soluble precursor, Fe(CO)6, for coprocessing of Illinois No. 6 coal with Maya ATB residuum (650 °F+) (Energy Fuels 1990, 4, 231-237). This paper addresses the activity and characterization of finely dispersed ironand molybdenum-containing catalysts based on the soluble precursors Fe(CO)5 and Mo(CO)6, and on the finely divided (average crystallite size of 30-80 A) sulfated metal oxide superacids such as Fe203/S042_ and Sn02/S042' for coprocessing reactions. The catalysts were characterized and tested for activity with various coals and Maya ATB heavy oil (650 °F) in coprocessing reactions. The following catalyst-coal combinations are reported: Fe(CO)5 with three premium Argonne coals; Mo(CO)6 and Mo naphthenate with Illinois No. 6; mixtures of Fe(CO)6 and Mo(CO)6 with Illinois No. 6; sulfated iron and tin oxides with Illinois No. 6; and a new catalyst, Mo-promoted sulfated iron oxide, with Illinois No. 6 coal. The use of a newly synthesized bimetallic catalyst, Mo/Fe203/S042", consisting of 50 ppm Mo and 3500 ppm iron, gave a 78% conversion of Illinois No. 6 coal to methylene chloride soluble products with a selectivity to oils of 80 wt % at 400 °C. The following order of catalyst activity (the yield of n-pentane-soluble products is referred to here as "activity") was observed for coprocessing reactions carried out with Illinois No. 6 coal and Maya ATB oil at 400 °C: Mo/ Fe203/S042' > Fe203/S042", Fe(CO)5/Mo(CO)6 > Mo(CO)6 > Fe(CO)5. The addition of elemental sulfur to the coal-oil mixture prior to the coprocessing reactions did not show any notable effect on conversions. Both hydrodenitrogenation (-40 %) and hydrodesulfurization (-60 %) were obtained with iron-molybdenum bimetallic catalysts based on sulfated oxides. We believe that the sulfate group in these catalysts helps to prevent sintering or agglomeration of catalysts at high temperatures. The high surface acidity of the catalyst may influence the nature of the reactions that occur in the early stages of coprocessing reactions but the catalyst activity is mainly due to the easy accessibility of the dissolved coal, heavy oil, and H2 to the small catalyst particles.

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