Do Specific Ion Effects on Collective Relaxation Arise from Perturbation of Hydrogen-Bonding Network Structure?

The change in the transport properties (i.e., water diffusivity, shear viscosity, etc.

Dielectric Characterization of HO and CO Uptake by Polyethylenimine Films.

The absorption of CO by polyethylenimine polymer (PEI) materials is of great interest in connection with proposed carbon capture technologies, and the successful development of this technology requires testing methods quantifying the amount of CO, HO, and reaction byproducts under operating conditions. We anticipate that dielectric measurements have the potential for quantifying both the extent of CO and HO absorption within the PEI matrix material as well as insights into subsequent reaction byproducts that can be expected to occur in the presence of moisture. The complexity of the chemistry involved in this reactive binding process clearly points to the need for the use of additional spectroscopic techniques to better resolve the multiple components involved and to validate the model-dependent findings from the dielectric measurements.

Deep Few-view High-resolution Photon-counting Extremity CT at Halved Dose for a Clinical Trial.

The latest X-ray photon-counting computed tomography (PCCT) for extremity allows multi-energy high-resolution (HR) imaging for tissue characterization and material decomposition. However, both radiation dose and imaging speed need improvement for contrast-enhanced and other studies. Despite the success of deep learning methods for 2D few-view reconstruction, applying them to HR volumetric reconstruction of extremity scans for clinical diagnosis has been limited due to GPU memory constraints, training data scarcity, and domain gap issues.

Molecular Dynamics Simulation of the Influence of Temperature and Salt on the Dynamic Hydration Layer in a Model Polyzwitterionic Polymer PAEDAPS.

We investigate the hydration of poly(3-[2-(acrylamido) ethyldimethylammonio] propanesulfonate) over a range of temperatures in pure water and with the inclusion of 0.1 mol/L NaCl using atomistic molecular dynamics simulation. Drawing on concepts drawn from the field of glass-forming liquids, we use the Debye-Waller parameter (<>) for describing the water mobility gradient around the polybetaine backbone extending to an overall distance ≈18 Å.

Approach to Cystic Lesions in the Abdomen and Pelvis, with Radiologic-Pathologic Correlation.

Cystic lesions found in and around the peritoneal cavity can often be challenging to diagnose owing to significant overlap in imaging appearance between the different entities. When the cystic lesion can be recognized to arise from one of the solid abdominal organs, the differential considerations can be more straightforward; however, many cystic lesions, particularly when large, cannot be clearly associated with one of the solid organs. Cystic lesions arising from the mesentery and peritoneum are less commonly encountered and can be caused by relatively rare entities or by a variant appearance of less-rare entities.

DFT Analysis of Organotin Catalytic Mechanisms in Dehydration Esterification Reactions for Terephthalic Acid and 2,2,4,4-Tetramethyl-1,3-cyclobutanediol.

Polyesters synthesized from 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) and terephthalic acid (TPA) are improved alternatives to toxic polycarbonates based on bisphenol A. In this work, we use ωB97X-D/LANL2DZdp calculations, in the presence of a benzaldehyde polarizable continuum model solvent, to show that esterification of TMCD and TPA will reduce and subsequently dehydrate a dimethyl tin oxide catalyst, becoming ligands on the now four-coordinate complex. This reaction then proceeds most plausibly by an intramolecular acyl-transfer mechanism from the tin complex, aided by a coordinated proton donor such as hydronium.

SAFT-γ-Mie Cross-Interaction Parameters from Density Functional Theory-Predicted Multipoles of Molecular Fragments for Carbon Dioxide, Benzene, Alkanes, and Water.

Determining unlike-pair interaction parameters, whether for group contribution equation of state or molecular simulations, is a challenge for the prediction of thermodynamic properties. As the number of components and their respective complexity increase, it becomes impractical to fit all the unlike interactions. Lorentz-Berthelot combining rules work well for systems, where the main interactions are dispersion forces, but they do not account for electrostatics.

Morphology and proton diffusion in a coarse-grained model of sulfonated poly(phenylenes).

A coarse-grained model previously used to simulate Nafion using dissipative particle dynamics (DPD) is modified to describe sulfonated Diels-Alder poly(phenylene) (SDAPP) polymers. The model includes a proton-hopping mechanism similar to the Grotthuss mechanism. The intramolecular parameters for SDAPP are derived from atomistic molecular dynamics (MD) simulation using the iterative Boltzmann inversion.

Proteomics Analysis Reveals Novel RASSF2 Interaction Partners.

RASSF2 is a tumor suppressor that shares homology with other Ras-association domain (RASSF) family members. It is a powerful pro-apoptotic K-Ras effector that is frequently inactivated in many human tumors. The exact mechanism by which RASSF2 functions is not clearly defined, but it likely acts as a scaffolding protein, modulating the activity of other pro-apoptotic effectors, thereby regulating and integrating tumor suppressor pathways.

Cell cycle restriction is more important than apoptosis induction for RASSF1A protein tumor suppression.

The Ras association domain family protein 1A (RASSF1A) is arguably one of the most frequently inactivated tumor suppressors in human cancer. RASSF1A modulates apoptosis via the Hippo and Bax pathways but also modulates the cell cycle. In part, cell cycle regulation appears to be dependent upon the ability of RASSF1A to complex with microtubules and regulate their dynamics.

Dissociating nociceptive modulation by the duration of pain anticipation from unpredictability in the timing of pain.

Objective: Waiting longer to receive pain increases its perceived unpleasantness by inducing 'dread'. However, it is not clear how unpredictability in the timing of the impending pain stimulus interacts with dread and whether the two factors show differential effects on the neural generators of the pain-evoked response.

Methods: We manipulated the duration of anticipation of laser-induced pain independently of unpredictability of stimulus delivery timing, to observe the relative effect on P2 amplitudes of the laser-evoked potential (LEP) response and its estimated sources.

Strategy for reversing resistance to a single anticancer agent in human prostate and pancreatic carcinomas.

Effective therapies for most solid cancers, especially those that have progressed to metastasis, remain elusive because of inherent and acquired resistance of tumor cells to conventional treatments. Additionally, the effective therapeutic window for many protocols can be very narrow, frequently resulting in toxicity. The present study explores an anticancer strategy that effectively eliminates resistant cancer cells without exerting deleterious effects on normal cells.

Vitamin C prevents the effects of prenatal nicotine on pulmonary function in newborn monkeys.

Smoking during pregnancy leads to decreased pulmonary function and increased respiratory illness in offspring. Our laboratory has previously demonstrated that many effects of smoking during pregnancy are mediated by nicotine. We now report that vitamin C supplementation can prevent some of the effects of maternal nicotine exposure on pulmonary function of offspring.

Model and field studies of the degradation of cross-linked polyacrylamide gels used during the revegetation of slate waste.

Cross-linked polyacrylamide gels are increasingly being used in environmental restoration schemes and horticulture as a means of enhancing water supply to plants. However, the environmental impact of cross-linked polyacrylamide gel deployment in soil remains poorly understood. This study assessed the chemical, physical and biological properties of new and field-conditioned cross-linked polyacrylamide gels.

Effects of prenatal nicotine exposure on primate brain development and attempted amelioration with supplemental choline or vitamin C: neurotransmitter receptors, cell signaling and cell development biomarkers in fetal brain regions of rhesus monkeys.

Studies in developing rodents indicate that nicotine is a neuroteratogen that disrupts brain development by stimulating nicotinic acetylcholine receptors (nAChRs) that control neural cell replication and differentiation. We administered nicotine to pregnant Rhesus monkeys from gestational day 30 through 160 by continuous infusion, achieving maternal plasma levels comparable to those in smokers (30 ng/ml). Fetal brain regions and peripheral tissues were examined for nAChR subtypes, other neurotransmitter receptors, and indices of cell signaling and cell damage.

Cell cycle- and protein kinase C-specific effects of resiniferatoxin and resiniferonol 9,13,14-ortho-phenylacetate in intestinal epithelial cells.

We have previously reported that protein kinase C (PKC) signaling can trigger hallmark events of cell cycle withdrawal in intestinal epithelial cells, including downregulation of cyclin D1, induction of p21(Waf1/Cip1), and activation of the growth suppressor function of pocket proteins. In the current study, we compared the cell cycle- and PKC-specific effects of the vanilloid resiniferatoxin (RTX), its parent diterpene resiniferonol 9,13,14-ortho-phenylacetate (ROPA), and the PKC agonist PMA in the IEC-18 non-transformed intestinal crypt cell line. ROPA and PMA were found to produce strikingly similar alterations in cell cycle progression and PKC activity in IEC-18 cells, although PMA was approximately 1000-fold more potent in producing these effects.

Involvement of the ERK signaling cascade in protein kinase C-mediated cell cycle arrest in intestinal epithelial cells.

We have reported previously that protein kinase C (PKC) signaling can mediate a program of cell cycle withdrawal in IEC-18 nontransformed intestinal crypt cells, involving rapid disappearance of cyclin D1, increased expression of Cip/Kip cyclin-dependent kinase inhibitors, and activation of the growth suppressor function of pocket proteins. In the current study, we present evidence to support a requisite role for PKC alpha in mediating these effects. Furthermore, analysis of the signaling events linking PKC/PKC alpha activation to changes in the cell cycle regulatory machinery implicate the Ras/Raf/MEK/ERK cascade.