Induced spin filtering in electron transmission through chiral molecular layers adsorbed on metals with strong spin-orbit coupling.

Recent observations of considerable spin polarization in photoemission from metal surfaces through monolayers of chiral molecules were followed by several efforts to rationalize the results as the effect of spin-orbit interaction that accompanies electronic motion on helical, or more generally strongly curved, potential surfaces. In this paper we (a) argue, using simple models, that motion in curved force-fields with the typical energies used and the characteristic geometry of DNA cannot account for such observations; (b) introduce the concept of induced spin filtering, whereupon selectivity in the transmission of the electron orbital angular momentum can induce spin selectivity in the transmission process provided there is strong spin-orbit coupling in the substrate; and (c) show that the spin polarization in the tunneling current as well as the photoemission current from gold covered by helical adsorbates can be of the observed order of magnitude. Our results can account for most of the published observations that involved gold and silver substrates; however, recent results obtained with an aluminum substrate can be rationalized within the present model only if strong spin-orbit coupling is caused by the built-in electric field at the molecule-metal interface.

Differential joint-specific corticospinal tract projections within the cervical enlargement.

The motor cortex represents muscle and joint control and projects to spinal cord interneurons and-in many primates, including humans-motoneurons, via the corticospinal tract (CST). To examine these spinal CST anatomical mechanisms, we determined if motor cortex sites controlling individual forelimb joints project differentially to distinct cervical spinal cord territories, defined regionally and by the locations of putative last-order interneurons that were transneuronally labeled by intramuscular injection of pseudorabies virus. Motor cortex joint-specific sites were identified using intracortical-microstimulation.

Polydnaviral ankyrin proteins aid parasitic wasp survival by coordinate and selective inhibition of hematopoietic and immune NF-kappa B signaling in insect hosts.

Polydnaviruses are mutualists of their parasitoid wasps and express genes in immune cells of their Lepidopteran hosts. Polydnaviral genomes carry multiple copies of viral ankyrins or vankyrins. Vankyrin proteins are homologous to IκB proteins, but lack sequences for regulated degradation.

Spatial frequency analysis for detecting early stage of cancer in human cervical tissues.

Spatial frequency spectra from cervical intraepithelial neoplasia (CIN) tissues are used to detect differences among different grades of human cervical tissues. The randomness of the structures of tissues from normal to different stages of CIN tissues is recognized by analyzing the spatial frequency. This study offers a simpler and better way to recognize the alterations among normal and different stages of CIN tissue, which are reflected by spatial information containing within the periodic or random structures of different types of tissue.

In vitro effects of insulin and RPE on choroidal and scleral components of eye growth in chicks.

In chick eyes, exogenous insulin prevents the choroidal thickening caused by wearing positive lenses and increases ocular elongation and scleral glycosaminoglycan (GAG) synthesis, an indicator of eye growth. Using in vitro eye-cups, a novel experimental system, we examined the role of the retinal pigment epithelium (RPE) and insulin on choroidal thickness and scleral GAG synthesis. Specifically, we asked whether insulin causes the release of diffusible factors from the RPE that affect the choroid.

Severe multisensory speech integration deficits in high-functioning school-aged children with Autism Spectrum Disorder (ASD) and their resolution during early adolescence.

Under noisy listening conditions, visualizing a speaker's articulations substantially improves speech intelligibility. This multisensory speech integration ability is crucial to effective communication, and the appropriate development of this capacity greatly impacts a child's ability to successfully navigate educational and social settings. Research shows that multisensory integration abilities continue developing late into childhood.

Reactions of three halogenated organophosphorus flame retardants with reduced sulfur species.

Tris(haloalkyl)phosphates (THAPs) are among the most widely used flame retardants in the U.S. They have been identified as one of the most frequently detected contaminants in U.

Native fluorescence spectroscopy reveals spectral differences among prostate cancer cell lines with different risk levels.

The spectral changes of native fluorophores among normal fibroblasts and cancer cell lines of different metastatic ability are investigated by fluorescence spectroscopy. The normal (fibroblast), moderately metastatic (DU-145), and advanced metastatic (PC-3) cell lines were each selectively excited at 300 nm, and their fluorescence emission spectra are analyzed using principal component analysis to explore the differences of the relative contents of tryptophan and reduced nicotinamide adenine dinucleotide in these cell lines. The results show that the tryptophan emission featured predominantly in the fluorescence spectra of the advanced metastatic cancer cells in comparison with the moderately metastatic cancer and normal cells.

Colloidal adsorption at fluid interfaces: regime crossover from fast relaxation to physical aging.

The adsorption of a colloidal particle at a fluid interface is studied theoretically and numerically, documenting distinctly different relaxation regimes. The adsorption of a perfectly smooth particle is characterized by a fast exponential relaxation to thermodynamic equilibrium where the interfacial free energy reaches the global minimum. The short relaxation time is given by the ratio of viscous damping to capillary forces.

Differential arrest and adhesion of tumor cells and microbeads in the microvasculature.

To investigate the mechanical mechanisms behind tumor cell arrest in the microvasculature, we injected fluorescently labeled human breast carcinoma cells or similarly sized rigid beads into the systemic circulation of a rat. Their arrest patterns in the microvasculature of mesentery were recorded and quantified. We found that 93% of rigid beads were arrested either at arteriole-capillary intersections or in capillaries.

Molecular dynamics simulations of the evaporation of particle-laden droplets.

We use molecular dynamics simulations to study the evaporation of particle-laden droplets on a heated surface. The droplets are composed of a Lennard-Jones fluid containing rigid particles, which are spherical sections of an atomic lattice, and heating is controlled through the temperature of an atomistic substrate. We observe that sufficiently large (but still nanosized) particle-laden drops exhibit contact line pinning, measure the outward fluid flow field which advects particles to the drop rim, and find that the structure of the resulting aggregate varies with interparticle and droplet-wall interactions.

A lipobead microarray assembled by particle entrapment in a microfluidic obstacle course and used for the display of cell membrane receptors.

Platforms which can display cell membrane ligands and receptors as a microarray library of probes for screening against a target are essential tools in drug discovery, biomarker identification, and pathogen detection. Membrane receptors and ligands require their native bilayer environment to retain their selectivity and binding affinity, and this complicates displaying them in a microarray platform. In this study, a design is developed in which the probes are first incorporated in supported lipid bilayers formed around micron-sized particles (lipobeads), and the microbeads themselves are then arrayed on a surface by hydrodynamic capture in a microfluidic obstacle course of traps.

Prior buprenorphine experience is associated with office-based buprenorphine treatment outcomes.

Objectives: As buprenorphine treatment and illicit buprenorphine use increase, many patients seeking buprenorphine treatment will have had prior experience with buprenorphine. Little evidence is available to guide optimal treatment strategies for patients with prior buprenorphine experience. We examined whether prior buprenorphine experience was associated with treatment retention and opioid use.

Hydrodynamically driven colloidal assembly in dip coating.

We study the hydrodynamics of dip coating from a suspension and report a mechanism for colloidal assembly and pattern formation on smooth substrates. Below a critical withdrawal speed where the coating film is thinner than the particle diameter, capillary forces induced by deformation of the free surface prevent the convective transport of single particles through the meniscus beneath the film. Capillary-induced forces are balanced by hydrodynamic drag only after a minimum number of particles assemble within the meniscus.

Optical detection of meat spoilage using fluorescence spectroscopy with selective excitation wavelength.

The native fluorescence (FL) spectra of muscle foods (meat) stored at 4 °C (refrigerated) and 25 °C (at room temperature) were measured with the selected excitation wavelength of 340 nm as a function of storage time to detect the meat spoilage status. The contributions of the principal biochemical components to the FL spectra were extracted using Multivariate Curve Resolution with Alternating Least-Squares (MCR-ALS). The change of the reduced nicotinamide adenine dinucleotide (NADH) content was found from the measured FL spectra and the MCR-ALS analysis, which reflects the microbial spoilage of muscle foods involved in the metabolic processes.

dMyc expression in the fat body affects DILP2 release and increases the expression of the fat desaturase Desat1 resulting in organismal growth.

Drosophila dMyc (dMyc) is known for its role in cell-autonomous regulation of growth. Here we address its role in the fat body (FB), a metabolic tissue that functions as a sensor of circulating nutrients to control the release of Drosophila Insulin-like peptides (Dilps) from the brain influencing growth and development. Our results show that expression of dMyc in the FB affects development and animal size.

Optical spectral fingerprints of tissues from patients with different breast cancer histologies using a novel fluorescence spectroscopic device.

The fluorescence of paired human breast malignant and normal tissue samples was investigated using a novel fluorescence spectroscopic (S3-LED) ratiometer unit with no moving parts. This device can measure the emission spectra of key native organic biomolecules such as tryptophan, tyrosine, collagen and elastin within tissues by using LED (light emitting diode) excitation sources coupled to an optical fiber. With this device, the spectral profiles of 11 paired breast cancerous and normal samples from 11 patients with breast carcinoma were obtained.

Intact inhibitory control processes in abstinent drug abusers (II): a high-density electrical mapping study in former cocaine and heroin addicts.

Response inhibition deficits are well-documented in drug users, and are related to the impulsive tendencies characteristic of the addictive phenotype. Addicts also show significant motivational issues that may accentuate these inhibitory deficits. We investigated the extent to which these inhibitory deficits are present in abstinence.

Cellular effects of acute direct current stimulation: somatic and synaptic terminal effects.

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique to modulate cortical excitability. Although increased/decreased excitability under the anode/cathode electrode is nominally associated with membrane depolarization/hyperpolarization, which cellular compartments (somas, dendrites, axons and their terminals) mediate changes in cortical excitability remains unaddressed. Here we consider the acute effects of DCS on excitatory synaptic efficacy.

Intact inhibitory control processes in abstinent drug abusers (I): a functional neuroimaging study in former cocaine addicts.

Neuroimaging studies in current cocaine dependent (CD) individuals consistently reveal cortical hypoactivity across regions of the response inhibition circuit (RIC). Dysregulation of this critical executive network is hypothesized to account for the lack of inhibitory control that is a hallmark of the addictive phenotype, and chronic abuse is believed to compound the issue. A crucial question is whether deficits in this circuit persist after drug cessation, and whether recovery of this system will be seen after extended periods of abstinence, a question with implications for treatment course and outcome.

Temporal integration of visual signals in lens compensation (a review).

Postnatal eye growth is controlled by visual signals. When wearing a positive lens that causes images to be focused in front of the retina (myopic defocus), the eye reduces its rate of ocular elongation and increases choroidal thickness to move the retina forward to meet the focal plane of the eye. When wearing a negative lens that causes images to be focused behind the retina (hyperopic defocus), the opposite happens.

Transcranial electrical stimulation accelerates human sleep homeostasis.

The sleeping brain exhibits characteristic slow-wave activity which decays over the course of the night. This decay is thought to result from homeostatic synaptic downscaling. Transcranial electrical stimulation can entrain slow-wave oscillations (SWO) in the human electro-encephalogram (EEG).

Native fluorescence spectra of human cancerous and normal breast tissues analyzed with non-negative constraint methods.

The native fluorescence spectra of human cancerous and normal breast tissues were investigated using the selected excitation wavelength of 340 nm to excite key building block molecules, such as reduced nicotinamide adenine dinucleotide (NADH), collagen, and flavin. The measured emission spectra were analyzed using a non-negative constraint method, namely multivariate curve resolution with alternating least-squares (MCR-ALS). The results indicate that the biochemical changes of tissue can be exposed by native fluorescence spectra analysis.

Mechano-sensing and transduction by endothelial surface glycocalyx: composition, structure, and function.

The endothelial cells (ECs) lining every blood vessel wall are constantly exposed to the mechanical forces generated by blood flow. The EC responses to these hemodynamic forces play a critical role in the homeostasis of the circulatory system. To ensure proper EC mechano-sensing and transduction, there are a variety of mechano-sensors and transducers that have been identified on the EC surface, intra- and trans-EC membrane and within the EC cytoskeleton.

Mini review of ultrafast fluorescence polarization spectroscopy [invited].

A mini review is presented on the theory, experiment, and application of the ultrafast fluorescence polarization dynamics and anisotropy with examples of two important medical dyes, namely Indocyanine Green and fluorescein. The time-resolved fluorescence polarization spectra of fluorescent dyes were measured with the excitation of a linearly polarized femtosecond laser pulse, and detected using a streak camera. The fluorescence emitted from the dyes is found to be partially oriented (polarized), and the degree of polarization of emission decreases with time.