Brownian Adhesive Dynamics (BRAD) for Simulating the Receptor-Mediated Binding of Viruses

Current viral docking models have relied upon the assumption that bond formation and breakage are independent of viral and docking surface geometry, as well as the forces exerted on the bonds. This assumption, known as the equivalent site hypothesis (ESH), is examined in detail using a newly developed simulation technique—Brownian adhesive dynamics (BRAD). The simulation couples the thermal motion of viral particles with adhesive dynamics models to characterize the effect of bonding on viral motion. We use the binding of HIV-like particles to CD4 expressing cells as a model system to illustrate the utility of BRAD. Comparison of the transition rates between bound states predicted by ESH and the rates resulting from BRAD simulations show dramatic differences; at values of the equilibrium crosslinking constant, KxRT, where ESH suggests all virus adhesion proteins will be bound (KxRT = 106), BRAD predicts not all virus adhesion proteins will be bound. At values of the equilibrium crosslinking constant used in typical ESH calculations of virus docking (KxRT = 1) we find BRAD simulations predict no binding. The mean bond density from BRAD models is often much lower than that predicted by ESH for equivalent parameter values. BRAD suggests that the viruses are much less well bound than ESH predicts. The differences suggest that binding models for viruses need to be reexamined closely. BRAD is a simulation technique that will be useful for quantifying the receptor-mediated binding of a wide variety of viruses to cells

HIV Viral Docking: Model Predictions for Bond Number and Trajectory

Viruses are nano-scale pathogenic particles. Understanding viral attachment is important to understand infectivity, disease transmission, and virus propagation throughout the host. A new simulation technique has been developed to study viral docking behavior - Brownian Adhesive Dynamics (BRAD). BRAD couples Brownian motion algorithm with adhesive dynamic models, and incorporates the effect of virus/cell geometry - an improvement over previous models. The method is extendable to any virus/cell system as well as nanoparticle adhesion system. Current studies have focused on the HIV/CD4 cell system. Comparison of BRAD simulation predictions with those of previous models of viral ducking has shown differences in steady state bond number and bond trajectory. This indicates that geometry of the system plays a significant role in the bonding behavior of viruses. Thus, it is shown that the equivalent site hypothesis is suspect

Supraclavicularis proprius muscle associated with supraclavicular nerve entrapment

Entrapment neuropathy of the supraclavicular nerve is rare and, when it occurs, is usually attributable to branching of the nerve into narrow bony clavicular canals. We describe another mechanism for entrapment of this nerve with the aberrant muscle; supraclavicularis being found during the routine dissection of an embalmed 82-year-old cadaver. Our report details a unique location for this rare muscular variation whereby the muscle fibres originated posteriorly on the medial aspect of the clavicle before forming a muscular arch over the supraclavicular nerve and passing laterally towards the trapezius and acromion. We recommend that in clinical instances of otherwise unexplained unilateral clavicular pain or tenderness, nerve compression from the supraclavicularis muscle must be borne in mind.

Molecular Beam Measurement of the Hyperfine Structure of 85Rb19F

Radio‐frequency transitions between the hfs levels of the J=1 rotational state in 85Rb19F have been observed using a molecular beam electric resonance spectrometer. From these spectra we have obtained values for the constant eq1Q1, which characterizes the interaction between the electric quadrupole moment of the Rb nucleus with the molecular electric‐field gradient; for the constants c1 and c2 which characterize the magnetic interaction between the Rb and F nuclei, respectively, and the rotational angular momentum J of the molecule; and for the constants c3 and c4 which describe the magnetic coupling of the two nuclear spins. Measurements have been made on the first‐five vibrational states. The results for v=0 areeq1Q1=(−70.342±0.001)MHz,c1=(+0.52±0.02)kHz,c2=(+10.615±0.06)kHz,c3=(+0.80±0.06)kHz,c4=(+0.15±0.05)kHz.Values of these constants for v=1, 2, 3, and 4 are given with somewhat less precision.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69352/2/JCPSA6-45-10-3731-1.pd

Triple Resonance Method for Molecular hfs Spectroscopy: Measurements on 133Cs19F

Three sequential oscillatory fields are employed in a molecular beam electric resonance spectrometer in order to observe molecular hfs transitions which do not obey the criteria for observability in the usual beam apparatus. The triple resonance method has been used to examine the hfs of CsF under conditions of very weak external fields. The method shows considerable promise for the detailed study of molecular hfs when more than one nucleus has a quadrupole moment, and for the observation of transitions at audio frequencies between closely spaced molecular energy levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70906/2/JCPSA6-47-10-3904-1.pd

A Systematic Review of Electronic Portal Usage Among Patients with Diabetes

The objectives of this review were (1) to examine characteristics associated with enrollment and utilization of portals among patients with diabetes and (2) to identify barriers and facilitators of electronic patient portal enrollment and utilization. PubMed and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) were systematically searched for papers reporting original research using quantitative or qualitative methods on characteristics, barriers, and facilitators associated with portal enrollment and utilization among patients with diabetes in the United States. The search was limited to articles published between February 1, 2005 (the date of the national symposium on personal health records) and January 1, 2014. Sixteen articles were identified. Of these, nine were quantitative, three were qualitative, and four used mixed-methods. Several demographic characteristics, having better-controlled diabetes, and providers who engaged in and encouraged portal use were associated with increased portal enrollment and utilization. Barriers to portal enrollment included a lack of patient (1) capacity, (2) desire, and (3) awareness of portal/portal functions. Barriers to portal utilization included (1) patient capacity, (2) lack of provider and patient buy-in to portal benefits, and (3) negative patient experiences using portals. Facilitators of portal enrollment and utilization were providers and family members recommending and engaging in portal use. Improved usability, increased access, educating patients how to use and benefit from portals, and greater endorsement by providers and family members might increase portal enrollment and utilization. As more providers and hospitals offer portals, addressing barriers and leveraging facilitators may help patients with diabetes achieve potential benefits

What makes for prize-winning television?

We investigate the determinants of success in four international television awards festivals between 1994 and 2012. We find that countries with larger markets and greater expenditure on public broadcasting tend to win more awards, but that the degree of concentration in the market for television and rates of penetration of pay-per-view television are unrelated to success. These findings are consistent with general industrial organisation literature on quality and market size, and with media policy literature on public service broadcasting acting as a force for quality. However, we also find that ‘home countries’ enjoy a strong advantage in these festivals, which is not consistent with festival success acting as a pure proxy for television quality

Effect of immune system stimulation and divergent selection for residual feed intake on digestive capacity of the small intestine in growing pigs

Residual feed intake (RFI) is a measure of feed efficiency that reflects differences in the efficiency of the use of feed for maintenance and growth. The consequences of genetic selection for RFI on intestinal nutrient digestion capacity, particularly during immune system stimulation (ISS), are poorly documented. Our objective was to evaluate the impact of ISS and genetic selection for RFI on apparent ileal digestibility (AID) of nutrients, and intestinal nutrient transport and barrier function