Noise-Adaptive Non-Blind Image Deblurring.

This work addresses the problem of non-blind image deblurring for arbitrary input noise. The problem arises in the context of sensors with strong chromatic aberrations, as well as in standard cameras, in low-light and high-speed scenarios. A short description of two common classical approaches to regularized image deconvolution is provided, and common issues arising in this context are described.

Interplay between population firing stability and single neuron dynamics in hippocampal networks.

Neuronal circuits' ability to maintain the delicate balance between stability and flexibility in changing environments is critical for normal neuronal functioning. However, to what extent individual neurons and neuronal populations maintain internal firing properties remains largely unknown. In this study, we show that distributions of spontaneous population firing rates and synchrony are subject to accurate homeostatic control following increase of synaptic inhibition in cultured hippocampal networks.

Supramolecular electrostatic nanoassemblies for bacterial forensics.

Electrostatic nanoassemblies were employed to identify bacterial growth conditions. They comprise a cationic conjugated oligoelectrolyte and fluorescein-tagged ssDNA and were optimized with a hybrid, computational neural network model. The photoluminescence spectra contained the oligomer and sensitized fluorescein emission.

Solvent effect and time-dependent behavior of C-terminus-cysteine-modified cecropin P1 chemically immobilized on a polymer surface.

Sum frequency generation (SFG) vibrational spectroscopy has been applied to the investigation of peptide immobilization on a polymer surface as a function of time and peptide conformation. Surface immobilization of biological molecules is important in many applications such as biosensors, antimicrobial materials, biobased fuel cells, nanofabrication, and multifunctional materials. Using C-terminus-cysteine-modified cecropin P1 (CP1c) as a model, we investigated the time-dependent immobilization behavior in situ in real time.

Spin system assignment of homo-o-phenylene ethynylene oligomers.

We previously reported the synthesis and solution characterization of short o-phenylene ethynylene (oPE) foldamers. Proton correlation techniques are not adequate for NMR assignment in these compounds as the ethynylene linkers interrupt proton connectivity. In order to facilitate structural characterization and more fully harness the power of NMR, it is necessary to know the sequence of spin systems along the molecular backbone.

Solution 1H NMR confirmation of folding in short o-phenylene ethynylene oligomers.

Oligomers based on an o-phenylene ethynylene (oPE) backbone with polar substituents have been synthesized using Sonogashira methods. Folding of these extremely short oligomers was confirmed via 1D and 2D (NOESY) NMR methods. Utilizing electron-rich and electron-poor phenylene building blocks, variations of these oPE oligomers have been synthesized to determine the folded stability of pi-rich vs pi-poor vs pi-rich-pi-poor systems.

Apex exponents for polymer-probe interactions.

We consider self-avoiding polymers attached to the tip of an impenetrable probe. The scaling exponents gamma(1) and gamma(2), characterizing the number of configurations for the attachment of the polymer by one end, or at its midpoint, vary continuously with the tip's angle. These apex exponents are calculated analytically by epsilon expansion, and numerically by simulations in three dimensions.

Fluorous effect in proteins: de novo design and characterization of a four-alpha-helix bundle protein containing hexafluoroleucine.

Several studies have demonstrated that proteins incorporating fluorinated analogues of hydrophobic amino acids such as leucine and valine into their hydrophobic cores exhibit increased stability toward thermal denaturation and unfolding by guanidinium chloride. However, estimates for the increase in the thermodynamic stability of a protein (DeltaDeltaG(unfold)) afforded by the substitution of a hydrophobic amino acid with its fluorinated analogue vary quite significantly. To address this, we have designed a peptide that adopts an antiparallel four-helix bundle structure in which the hydrophobic core is packed with leucine, and investigated the effects of substituting the central two layers of the core with L-5,5,5,5',5',5'-hexafluoroleucine (hFLeu).

Kinetics of protein-DNA interaction: facilitated target location in sequence-dependent potential.

Recognition and binding of specific sites on DNA by proteins is central for many cellular functions such as transcription, replication, and recombination. In the process of recognition, a protein rapidly searches for its specific site on a long DNA molecule and then strongly binds this site. Here we aim to find a mechanism that can provide both a fast search (1-10 s) and high stability of the specific protein-DNA complex (Kd=10(-15)-10(-8) M).

Diffusion in correlated random potentials, with applications to DNA.

Many biological processes involve one-dimensional diffusion over a correlated inhomogeneous energy landscape with a correlation length xi(c). Typical examples are specific protein target location on DNA, nucleosome repositioning, or DNA translocation through a nanopore, in all cases with xi(c) approximately 10 nm. We investigate such transport processes by the mean first passage time (MFPT) formalism, and find diffusion times which exhibit strong sample to sample fluctuations.

Cation-pi interactions studied in a model coiled-coil peptide.

Cation-pi interactions between aromatic amino acids and the positively charged residues lysine and arginine have been proposed to play an important role in stabilizing protein structure. We have used a peptide that adopts a coiled coil structure as a model system to evaluate the energetic contribution of cation-pi interactions to protein folding. Peptides were designed in which phenylalanine, tyrosine, and tryptophan were placed at a solvent-exposed position of the helix, one turn removed from an arginine residue that could provide a favorable cation-pi interaction.

Azoospermia and oligospermia among a large cohort of DBCP applicators in 12 countries.

Azoospermia and oligospermia have been well demonstrated among workers exposed to 1,2-dibromo-3-chloropropane (DBCP) in manufacturing and formulation of this pesticide. After DBCP was banned in the United States in the late 1970s, two American companies continued to export it to many less developed countries. In the early to mid-1990s, attorneys assembled a cohort of approximately 26,400 male plaintiffs who, as workers on banana and pineapple plantations in 12 of these countries, had been exposed to DBCP, primarily during its application.

Recombinant RNA polymerase: inducible overexpression, purification and assembly of Escherichia coli rpo gene products.

The genes, rpoA, rpoB and rpoC of Escherichia coli, which encode the RNA polymerase alpha-, beta- and beta'-subunits, respectively, have been individually placed on expression plasmids under the control of the bacteriophage T7 promoter. Induction of the T7 RNA polymerase gene in host cells harboring each of the three plasmids resulted in the extensive overproduction of the three polypeptides. The overproduced subunits were purified and assembled into a functional enzyme, whose specific activity and dependence on the sigma-factor were indistinguishable from native RNA polymerase purified by conventional methods.

Gray scale ultrasound diagnosis of obstructive biliary disease.

B-mode ultrasound examinations have been useful in demonstrating cholelithiasis and obstructive dilatation of the gallbladder. It is now possible with gray scale ultrasound technique to demonstrate dilatation of the common bile duct, as differentiated from the gallbladder, and also to show fluid containing spaces within the liver. Discrimination between solid and fluid filled intrahepatic structures is readily made, and dilated biliary radicles are frequently discernible.