Cross-correlation frequency resolved optical gating analysis of broadband continuum generation in photonic crystal fiber: simulations and experiments.

Numerical simulations are used to study the temporal and spectral characteristics of broadband supercontinua generated in photonic crystal fiber. In particular, the simulations are used to follow the evolution with propagation distance of the temporal intensity, the spectrum, and the cross-correlation frequency resolved optical gating (XFROG) trace. The simulations allow several important physical processes responsible for supercontinuum generation to be identified and, moreover, illustrate how the XFROG trace provides an intuitive means of interpreting correlated temporal and spectral features of the supercontinuum.

Measurement of the lateral diffusion of human MHC class I molecules on HeLa cells by fluorescence recovery after photobleaching using a phycoerythrin probe.

The mobility of cell surface MHC class I molecules on HeLa cells was measured by fluorescence recovery after photobleaching (FRAP). The probe used for these studies was the phycobiliprotein R-phycoerythrin coupled to Fab fragments of a monoclonal antibody specific for human monomorphic MHC class I molecules. It was found that the recovery curves could be equally well fitted by either a random diffusion model with an immobile component or by an anomalous diffusion model.

Effect of sequential transdermal progesterone cream on endometrium, bleeding pattern, and plasma progesterone and salivary progesterone levels in postmenopausal women.

Background: Transdermal progesterone is being used in some countries as a purported treatment for menopausal symptoms, either alone or prescribed in conjunction with estrogen, but little information exists regarding the biological activity and effectiveness of this method of delivery of progesterone in protecting the endometrium from excess proliferation. This study was designed to evaluate the use of sequential transdermal progesterone. End-points evaluated included endometrial cellular response and bleeding pattern as well as plasma hormone levels and salivary progesterone estimations.

Primary Ewing's sarcoma/primitive neuroectodermal tumor of the kidney: a clinicopathologic and immunohistochemical analysis of 11 cases.

Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is an extraordinarily rare primary tumor in the kidney and can be mistaken for a variety of other round cell tumors, including blastema-predominant Wilms' tumor (WT). Approximately 90% of ES/PNET have a specific t(11;22), which results in a chimeric EWS-FLI-1 protein. Immunohistochemistry for the carboxy-terminus of FLI-1 is sensitive and highly specific for the diagnosis of ES/PNET.

Clinicopathologic features of nephrogenic rests and nephroblastomatosis.

Nephrogenic rests are the consequence of residual metanephric tissue in a fully developed kidney. They usually occur along the perimeter of a mature renal lobe (i.e.

Effects of the membrane dipole potential on the interaction of saquinavir with phospholipid membranes and plasma membrane receptors of Caco-2 cells.

The combined use of the membrane surface potential fluorescent sensor fluorescein phosphatidylethanolamine (FPE) and the membrane dipole potential fluorescent sensor di-8-ANEPPS to characterize the interaction of molecules with model and cellular membranes and to asses the influence of the dipole potential on the interaction is reported. The study of the human immunodeficiency virus protease inhibitor saquinavir with Caco-2 cells and phospholipid membranes reveals that the compound interacts with the lipidic bilayer of model membranes with a simple hyperbolic binding profile but with Caco-2 cells in a cooperative way involving membrane receptors. Additional studies indicated that colchicine acts as a competitor ligand to saquinavir and suggests, in agreement with other reports, that the identity of the saquinavir "receptor" could be P-glycoprotein or the multiple drug resistance-associated protein.

Free-electron lasers. Status and applications.

A free-electron laser consists of an electron beam propagating through a periodic magnetic field. Today such lasers are used for research in materials science, chemical technology, biophysical science, medical applications, surface studies, and solid-state physics. Free-electron lasers with higher average power and shorter wavelengths are under development.

The fusion domain of HIV gp41 interacts specifically with heparan sulfate on the T-lymphocyte cell surface.

Studies of the interaction of the 16 residue fusion peptide domain of human immunodeficiency virus glycoprotein gp41 (gp41(FD)) with T lymphocytes are outlined. Fluorescence measurements of changes in the electrostatic surface and dipole potentials of the plasma membrane following the interaction with gp41(FD) are described. The results show that gp41(FD) interacts with heparan sulfate located on the cell surface.

Effect of phloretin on the percutaneous absorption of lignocaine across human skin.

The potential use of phloretin, a polyphenolic compound, as a penetration enhancer in the transdermal delivery of lignocaine hydrochloride (L-HCl) has been investigated. Standard in vitro skin permeation methods, using excised human skin, were used to characterize the percutaneous absorption of L-HCl. Initially, phloretin was applied to the skin surface as a methanolic solution.

Immunohistochemical detection of FLI-1 protein expression: a study of 132 round cell tumors with emphasis on CD99-positive mimics of Ewing's sarcoma/primitive neuroectodermal tumor.

The histologic and immunohistochemical differentiation of Ewing' s sarcoma/primitive neuroectodermal tumor (ES/PNET) from other small, blue, round cell tumors may be difficult. Despite initial promise, CD99 (MIC2) has not proven to be a specific marker. Approximately 90% of ES/PNET have a specific t(11; 22)(q24;q12) that results in fusion of the EWS and FLI-1 genes, and overexpression of FLI-1 protein.

Energy transfer in nonequilibrium space-charge-dominated beams.

Space-charge modes similar to those observed in recent experiments appear in simulations of nonequilibrium charged particle beams with anisotropy. The modes couple degrees of freedom, causing energy transfer and equipartitioning without halo formation in just a few betatron wavelengths. The rate depends on a single free parameter quantifying the space-charge intensity of the final state.

Increased-bandwidth in ultrashort-pulse measurement using an angle-dithered nonlinear-optical crystal.

We show that the usual phase-matching-bandwidth constraint in ultrashort-laser-pulse measurement techniques is overly restrictive. Specifically, the phase-matching bandwidth need not exceed the pulse bandwidth on every pulse. Instead, only the phase-matching bandwidth integrated over the measurement period need exceed the pulse bandwidth.

Two-color operation in high-gain free-electron lasers.

Two-color operation in free-electron laser (FEL) amplifiers is studied using a 3D nonlinear polychromatic simulation. We assume the FEL is seeded at two closely spaced wavelengths within the gain band, and study the growth of the seeds and a discrete spectrum of beat waves that are outside the gain band. The beat waves grow parasitically due to electron bunching in the seeded waves with growth rates higher than the seeded waves.

Increased macrophage infiltration of gastric mucosa in Helicobacter pylori-infected children.

The purpose of the study was to quantify gastric mucosal macrophages and define their association with the histopathologic features of stomach biopsies obtained from Helicobacter pylori-infected and uninfected children. Endoscopically obtained gastric biopsies from symptomatic children were independently evaluated by two groups of pathologists. Thirty children were evaluated; 14 were H.

Characterization of the sequence of interactions of the fusion domain of the simian immunodeficiency virus with membranes. Role of the membrane dipole potential.

The simian immunodeficiency virus fusion peptide constitutes a 12-residue N-terminal segment of the gp32 protein that is involved in the fusion between the viral and cellular membranes, facilitating the penetration of the virus in the host cell. Simian immunodeficiency virus fusion peptide is a hydrophobic peptide that in Me(2)SO forms aggregates that contain beta-sheet pleated structures. When added to aqueous media the peptide forms large colloidal aggregates.

Membrane interactions of the putative fusion peptide (MF alpha P) from fertilin-alpha, the mouse sperm protein complex involved in fertilization.

Mammalian fertilization depends upon successful binding and fusion between the membranes of the spermatozoon and the oocyte. These processes are thought to be mediated by a series of protein-protein interactions in which sperm antigens known as fertilins are thought to play a key role. Using a recently developed fluorescence technique, the interactions of the oligopeptide sequence corresponding to the fusogenic domain of mouse fertilin-alpha (MF alpha P) and phospholipid vesicles have been investigated.

Ligand-dependent conformational equilibria of serum albumin revealed by tryptophan fluorescence quenching.

Ligand-dependent structural changes in serum albumin are suggested to underlie its role in physiological solute transport and receptor-mediated cellular selection. Evidence of ligand-induced (oleic acid) structural changes in serum albumin are shown in both time-resolved and steady-state fluorescence quenching and anisotropy measurements of tryptophan 214 (Trp214). These studies were augmented with column chromatography separations.

Amino acid sequences which promote and prevent the binding and membrane insertion of surface-active peptides: comparison of melittin and promelittin.

The temporal sequence of molecular events involved in the interactions of a number of related peptides with membranes are revealed using two complementary fluorescence techniques. Comparative studies are reported of the interactions of melittin, promelittin and a melittin analogue with trp-19 replaced with Ile and the n-terminal gly replaced with a trp residue, with phosphatidylcholine membranes. It is shown that the interaction of the n-terminal region of melittin rapidly binds and inserts into the body of the membrane with a rate constant of around 367 s-1.

Intramembrane molecular dipoles affect the membrane insertion and folding of a model amphiphilic peptide.

The relationship between the dipole potential and the interaction of the mitochondrial amphipathic signal sequence known as p25 with model membranes has been studied using 1-(3-sulfonatopropyl)-4-[beta[2-(di-n-octyl-amino)-6-naphthyl]viny l] pyridinium betaine (di-8-ANEPPS) as a fluorescent probe. The dipole potential of phosphatidylcholine membranes was modified by incorporating into the bilayer the sterols phloretin and 6-ketocholestanol (KC), which decrease and increase the dipole potential, respectively. The results derived from the application of a dual-wavelength ratiometric fluorescence method for following the variation of the membrane dipole potential have shown that when p25 inserts into the lipidic bilayer, a decrease in the dipole potential takes place.

Production of radioisotopes by direct electron activation.

High-energy electrons bombarded on materials can induce radioactivity by either directly knocking out neutrons or by first converting a fraction of the electron kinetic energy into electromagnetic energy, with subsequent neutron emission induced by the photons produced. The purpose of this paper was to develop a calculation method for estimating neutron emission and radionuclide production by high-energy (15-25 MeV) electrons directly interacting with a nucleus. The reaction (e,n) is considered using the method of virtual photons.

Fetus-in-fetu with malignant recurrence.

Fetus-in-fetu is an unusual condition in which a vertebrate fetus is enclosed within the abdomen of another fetus. These occurrences are usually benign. This report describes an instance of malignant recurrence after resection of a fetus-in-fetu.

Pathology of mucormycosis of cane toads in Australia.

The gross and microscopic pathology of a fungal septicaemia caused by the zygomycete. Mucor amphibiorum in 27 free-ranging cane toads, Bufo marinus, in Australia is described. Seven of the 27 toads had clinical signs of illness when discovered and five of these seven were moribund.

Time resolution of binding and membrane insertion of a mitochondrial signal peptide: correlation with structural changes and evidence for cooperativity.

Utilizing a recently developed novel fluorescence technique [Wall et al. (1995) Mol. Membr.