Dipole-mediated exciton management strategy enabled by reticular chemistry.

Selectively blocking undesirable exciton transfer pathways is crucial for utilizing exciton conversion processes that involve participation of multiple chromophores. This is particularly challenging for solid-state systems, where the chromophores are fixed in close proximity. For instance, the low efficiency of solid-state triplet-triplet upconversion calls for inhibiting the parasitic singlet back-transfer without blocking the flow of triplet excitons.

Synthesis of Amino[2.2]paracyclophanes-Beneficial Monomers for Bioactive Coating of Medical Implant Materials.

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Hindered transport of macromolecules through a single row of cylinders: application to glomerular filtration.

The slit diaphragms of renal glomerular capillaries form an ultrafiltration barrier which may be approximated as a row of cylindrical fibers of macromolecular dimensions. To describe the hindered transport of plasma proteins and other macromolecules through this barrier, we developed an approximate hydrodynamic model for spherical, Brownian particles passing through a row of infinitely long cylinders. The selectivity of the slit diaphragm was assessed by computing concentration profiles for a wide range of molecular sizes for Pe < or = 1, where Pe is a Peclet number based on the cylinder radius.

Helicobacter bilis sp. nov., a novel Helicobacter species isolated from bile, livers, and intestines of aged, inbred mice.

A fusiform bacterium with 3 to 14 multiple bipolar sheathed flagella and periplasmic fibers wrapped around the cell was isolated from the liver, bile, and lower intestine of aged, inbred mice. The bacteria grew at 37 and 42 degrees C under microaerophilic conditions, rapidly hydrolyzed urea, were catalase and oxidase positive, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and were resistant to both cephalothin and nalidixic acid but sensitive to metronidazole. On the basis of 16S rRNA gene sequence analysis, the organism was classified as a novel helicobacter, Helicobacter bilis.

Spontaneous development of inflammatory bowel disease in T cell receptor mutant mice.

We describe the spontaneous development of inflammatory bowel disease (IBD) in several immunodeficient mouse strains created via gene targeting in embryonic stem cells. Chronic colitis was observed in T cell receptor (TCR) alpha mutant, TCR beta mutant, TCR beta x delta double mutant, or class II major histocompatibility complex (MHC) mutant mice, but not in recombination-activating gene RAG-1 mutant mice or nude mice kept in the same specific pathogen-free animal facility. This clinical pattern suggests that the disease requires the presence of B lymphocytes and the absence of class II MHC-restricted CD4+ alpha beta T cells.

Solid state 31NMR studies of the conversion of amorphous tricalcium phosphate to apatitic tricalcium phosphate.

The hydrolytic conversion of a solid amorphous calcium phosphate of empirical formula Ca9 (PO4)6 to a poorly crystalline apatitic phase, under conditions where Ca2+ and PO4(3-) were conserved, was studied by means of solid-state magic-angle sample spinning 31P-NMR (nuclear magnetic resonance). Results showed a gradual decrease in hydrated amorphous calcium phosphate and the formation of two new PO4(3-)-containing components: an apatitic component similar to poorly crystalline hydroxyapatite and a protonated PO4(3-), probably HPO4(2-) in a dicalcium phosphate dihydrate (DCPD) brushite-like configuration. This latter component resembles the brushite-like HPO4(2-) component previously observed by 31P-NMR in apatitic calcium phosphates of biological origin.

A comparison of rodent caging systems based on microenvironmental parameters.

Four different mouse caging systems were evaluated for microenvironmental temperature, carbon dioxide, relative humidity (RH) and ammonia levels during a 7-day testing period. All caging systems evaluated had polycarbonate bases and consisted of either a molded polyester (MP) filter lid, one of two different polycarbonate filter lids, or no filter lid which served as a control. At 50% macroenvironmental RH (study I), all systems maintained an intracage temperature of 75.

Motion perception in the peripheral visual field.

Thresholds were determined for the perception of the motion of a single bar moving at different positions in the field of view. Performance in the temporal hemified was slightly superior to that in the nasal hemifield and depended on the orientation as well as on the direction of the motion. The perception of horizontal motion was better than that of vertical motion.

Stimulation of human prostatic carcinoma cell growth by factors present in human bone marrow.

Malignant prostatic carcinoma, a major cause of cancer mortality in males, most often metastasizes to secondary sites in bone. Frequently, the growth rate of the secondary tumor in bone marrow is considerably greater than that of the slowly growing primary prostatic tumor. We now report that two lines of human prostatic carcinoma cells proliferate in response to conditioned media from unstimulated human, rat, or bovine bone marrow.

Picosecond optical breakdown: tissue effects and reduction of collateral damage.

The effects of picosecond laser-induced optical breakdown on tissue were investigated using high-intensity 40 ps Nd:YAG laser pulses at 1.06 microns. Tissue damage was evaluated using the corneal endothelium in vitro as a model system.

The radiation impedance of the external ear of cat: measurements and applications.

The configuration of external ears varies dramatically among mammalian species. In order to relate these structural differences to acoustic performance, it is useful to determine the "output" (radiation) impedance of the external ear. Measurements were made of the radiation impedance ZE of the cat external ear looking out from the location of the tympanic membrane.

Chemical probing of the B-Z transition in negatively supercoiled DNA.

An analysis of the B-to-Z transition as a function of supercoiling for a natural Z-DNA-forming sequence found in plasmid pBR322 is presented at nucleotide resolution. The analysis is based on reactivity to four chemical probes which exhibit hyperreactivity in the presence of Z-DNA: hydroxylamine, osmium tetroxide, diethyl pyrocarbonate and dimethyl sulfate. We find that the initial transition occurs largely within a 14 base pair region which is mostly alternating purines and pyrimidines.