Cooperativity and Frustration in Protein-Mediated Parallel Actin Bundles

We examine the mechanism of bundling of cytoskeletal actin filaments by two representative bundling proteins, fascin and espin. Small-angle X-ray studies show that increased binding from linkers drives a systematic \textit{overtwist} of actin filaments from their native state, which occurs in a linker-dependent fashion. Fascin bundles actin into a continuous spectrum of intermediate twist states, while espin only allows for untwisted actin filaments and fully-overtwisted bundles. Based on a coarse-grained, statistical model of protein binding, we show that the interplay between binding geometry and the intrinsic \textit{flexibility} of linkers mediates cooperative binding in the bundle. We attribute the respective continuous/discontinous bundling mechanisms of fascin/espin to differences in the stiffness of linker bonds themselves.Comment: 5 pages, 3 figures, figure file has been corrected in v

Stress Sensing in Polycaprolactone Films via an Embedded Photochromic Compound

A photochromic polymer exhibiting mechanochromic behavior is prepared by means of ring-opening polymerization (ROP) of epsilon-caprolactone by utilizing a difunctional indolinospiropyran as an initiator. The configuration of having the photochromic initiating species within the polymer backbone leads to a mechanochromic effect with deformation of polymer films leading to ring-opening of the spiro C-O bond to form the colored merocyanine. Active stress monitoring by dynamic mechanical analysis (DMA) in tension mode was used to probe the effects of UV irradiation on polymer films held under constant strain. Irradiation with UV light induces a negative change in the polymer stress of approximately 50 kPa. Finally, a model of the mechanochromic effect was performed using density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. A sharp increase in the relative molecular energy and the absorption wavelength as well as a drastic decrease in the spiro-oxygen atom charge occurred at a molecular elongation of >39%

Hall Mobility Measurements and Chemical Stability of Ultrathin, Methylated Si(111)-on-Insulator Films

The chemical and electronic properties of 10−20 nm thick, methylated Si(111)-on-insulator (CH_3/Si(111)_(SOI)) thin films, prepared using a wet chemical chlorination/methylation procedure, are investigated. X-ray photoelectron spectroscopy reveals that CH_3/Si(111)_(SOI) is resistant to oxidation upon exposure to air and to various device fabrication schemes and associated chemicals. Temperature-dependent Hall mobility measurements yield results that are dependent upon the duration of the chlorination step. For short-time chlorination steps, bulklike mobilities are observed, and the dominant scattering mechanism arises from ionized impurities. For longer time chlorination steps, surface roughness or neutral impurity scattering limit the carrier mobilities

Before and Beyond Divergence: A New Look at the Economic History of China and Europe [Book Review]

Before and Beyond Divergence is a model of collaboration and academic production: between two disciplines—economics and history and between two area specialists—an economic historian of Europe and a socioeconomic historian of China

Bowel dysfunction after transposition of intestinal segments into the urinary tract : 8-year prospective cohort study

Purpose Bowel function may be disturbed after intestinal segments are transposed into the urinary tract to reconstruct or replace the bladder. In 1997, our group were the first to report major bowel dysfunction in a cohort of such patients: up to 42% of those who were asymptomatic preoperatively describing new bowel symptoms postoperatively including explosive diarrhoea, nocturnal diarrhoea, faecal urgency, faecal incontinence and flatus leakage . We now describe bowel symptoms in this same cohort eight years later (2005). Materials and Methods 116 patients were evaluable. Of the remaining 37 from the original report: 30 had died, five no longer wished to be involved, and two could not be traced. Patients were asked to complete postal questionnaires identical to those used in the first follow-up, assessing the severity of bowel symptoms and quality of life using two validated instruments. Responses were compared with those from the original study. The Nottingham Health Profile quality of life scores were also compared to age and sex matched norms. Results 96 (83%) completed eight-year follow-up questionnaires: 43 after ileal conduit diversion (Group 1), 17 after clam enterocystoplasty for overactive bladder (Group 2), 18 after reconstructed bladder for neurogenic bladder dysfunction (Group 3), and 18 with bladder replacement for non-neurogenic causes (Group 4). High prevalence rates of bowel symptoms persisted with no statistically significant differences between the two time points. Of those with symptoms in 2005, around 50% had reported similar symptoms in 1997. Clam enterocystoplasty patients (Group 2) still reported the highest prevalence (59%) of troublesome diarrhoea with one in two on regular anti-diarrhoeal medication. They also had high rates of faecal incontinence (47%), faecal urgency (41%) and nocturnal bowel movement (18%); with high proportions reporting a moderate or severe adverse effect on work (36%), social life (50%) and sex life (43%). High rates were also reported by neurogenic bladder dysfunction patients, including 50% with troublesome diarrhoea. This symptom was reported by 19% after ileal conduit and by 17% after bladder replacement for non-neurogenic causes. The impact of bowel symptoms on every-day activities and quality of life persisted, remaining most severe after clam enterocystoplasty, with 24% regretting undergoing the procedure because of subsequent bowel symptoms. Conclusions: After more than eight years, operations involving transposition of intestinal segments continue to be associated with high rates of bowel symptoms, which impact on everyday activities. These are particularly troublesome following enterocystoplasty for overactive bladder and bladder reconstruction for neurogenic bladder dysfunction. These risks should influence patient selection and potential patients should be warned prior to surgery

Bowel dysfunction after transposition of intestinal segments into the urinary tract : 8-year prospective cohort study

Purpose Bowel function may be disturbed after intestinal segments are transposed into the urinary tract to reconstruct or replace the bladder. In 1997, our group were the first to report major bowel dysfunction in a cohort of such patients: up to 42% of those who were asymptomatic preoperatively describing new bowel symptoms postoperatively including explosive diarrhoea, nocturnal diarrhoea, faecal urgency, faecal incontinence and flatus leakage . We now describe bowel symptoms in this same cohort eight years later (2005). Materials and Methods 116 patients were evaluable. Of the remaining 37 from the original report: 30 had died, five no longer wished to be involved, and two could not be traced. Patients were asked to complete postal questionnaires identical to those used in the first follow-up, assessing the severity of bowel symptoms and quality of life using two validated instruments. Responses were compared with those from the original study. The Nottingham Health Profile quality of life scores were also compared to age and sex matched norms. Results 96 (83%) completed eight-year follow-up questionnaires: 43 after ileal conduit diversion (Group 1), 17 after clam enterocystoplasty for overactive bladder (Group 2), 18 after reconstructed bladder for neurogenic bladder dysfunction (Group 3), and 18 with bladder replacement for non-neurogenic causes (Group 4). High prevalence rates of bowel symptoms persisted with no statistically significant differences between the two time points. Of those with symptoms in 2005, around 50% had reported similar symptoms in 1997. Clam enterocystoplasty patients (Group 2) still reported the highest prevalence (59%) of troublesome diarrhoea with one in two on regular anti-diarrhoeal medication. They also had high rates of faecal incontinence (47%), faecal urgency (41%) and nocturnal bowel movement (18%); with high proportions reporting a moderate or severe adverse effect on work (36%), social life (50%) and sex life (43%). High rates were also reported by neurogenic bladder dysfunction patients, including 50% with troublesome diarrhoea. This symptom was reported by 19% after ileal conduit and by 17% after bladder replacement for non-neurogenic causes. The impact of bowel symptoms on every-day activities and quality of life persisted, remaining most severe after clam enterocystoplasty, with 24% regretting undergoing the procedure because of subsequent bowel symptoms. Conclusions: After more than eight years, operations involving transposition of intestinal segments continue to be associated with high rates of bowel symptoms, which impact on everyday activities. These are particularly troublesome following enterocystoplasty for overactive bladder and bladder reconstruction for neurogenic bladder dysfunction. These risks should influence patient selection and potential patients should be warned prior to surgery

Increasing Passersby Engagement with Public Large Interactive Displays: A Study of Proxemics and Conation

This is the author’s version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in the Proceedings of the 2018 International Conference on Human Factors on Computing Systems on the ACM Digital Library at https://dx.doi.org/10.1145/3279778.3279789Prior research has shown that large interactive displays de- ployed in public spaces are often underutilized, or even un- noticed, phenomena connected to ‘interaction’ and ‘display blindness’, respectively. To better understand how designers can mitigate these issues, we conducted a field experiment that compared how different visual cues impacted engagement with a public display. The deployed interfaces were designed to progressively reveal more information about the display and entice interaction through the use of visual content designed to evoke direct or indirect conation (the mental faculty related to purpose or will to perform an action), and different ani- mation triggers (random or proxemic). Our results show that random triggers were more effective than proxemic triggers at overcoming display and interaction blindness. Our study of conation – the first we are aware of – found that “conceptual” visuals designed to evoke indirect conation were also useful in attracting people’s attention.Natural Sciences and Engineering Research Council of Canad

PRIMUS: An observationally motivated model to connect the evolution of the AGN and galaxy populations out to z~1

We present an observationally motivated model to connect the AGN and galaxy populations at 0.2<z<1.0 and predict the AGN X-ray luminosity function (XLF). We start with measurements of the stellar mass function of galaxies (from the Prism Multi-object Survey) and populate galaxies with AGNs using models for the probability of a galaxy hosting an AGN as a function of specific accretion rate. Our model is based on measurements indicating that the specific accretion rate distribution is a universal function across a wide range of host stellar mass with slope gamma_1 = -0.65 and an overall normalization that evolves with redshift. We test several simple assumptions to extend this model to high specific accretion rates (beyond the measurements) and compare the predictions for the XLF with the observed data. We find good agreement with a model that allows for a break in the specific accretion rate distribution at a point corresponding to the Eddington limit, a steep power-law tail to super-Eddington ratios with slope gamma_2 = -2.1 +0.3 -0.5, and a scatter of 0.38 dex in the scaling between black hole and host stellar mass. Our results show that samples of low luminosity AGNs are dominated by moderately massive galaxies (M* ~ 10^{10-11} M_sun) growing with a wide range of accretion rates due to the shape of the galaxy stellar mass function rather than a preference for AGN activity at a particular stellar mass. Luminous AGNs may be a severely skewed population with elevated black hole masses relative to their host galaxies and in rare phases of rapid accretion.Comment: 11 pages, 5 figures, emulateapj format, updated to match version accepted for publication in Ap

Ensemble Sales Forecasting Study in Semiconductor Industry

Sales forecasting plays a prominent role in business planning and business strategy. The value and importance of advance information is a cornerstone of planning activity, and a well-set forecast goal can guide sale-force more efficiently. In this paper CPU sales forecasting of Intel Corporation, a multinational semiconductor industry, was considered. Past sale, future booking, exchange rates, Gross domestic product (GDP) forecasting, seasonality and other indicators were innovatively incorporated into the quantitative modeling. Benefit from the recent advances in computation power and software development, millions of models built upon multiple regressions, time series analysis, random forest and boosting tree were executed in parallel. The models with smaller validation errors were selected to form the ensemble model. To better capture the distinct characteristics, forecasting models were implemented at lead time and lines of business level. The moving windows validation process automatically selected the models which closely represent current market condition. The weekly cadence forecasting schema allowed the model to response effectively to market fluctuation. Generic variable importance analysis was also developed to increase the model interpretability. Rather than assuming fixed distribution, this non-parametric permutation variable importance analysis provided a general framework across methods to evaluate the variable importance. This variable importance framework can further extend to classification problem by modifying the mean absolute percentage error(MAPE) into misclassify error. Please find the demo code at : https://github.com/qx0731/ensemble_forecast_methodsComment: 14 pages, Industrial Conference on Data Mining 2017 (ICDM 2017

Exploiting Connections for Viral Replication.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the COVID-19 (coronavirus disease 2019) pandemic, is a positive strand RNA (+RNA) virus. Like other +RNA viruses, SARS-CoV-2 is dependent on host cell metabolic machinery to survive and replicate, remodeling cellular membranes to generate sites of viral replication. Viral RNA-containing double-membrane vesicles (DMVs) are a striking feature of +RNA viral replication and are abundant in SARS-CoV-2-infected cells. Their generation involves rewiring of host lipid metabolism, including lipid biosynthetic pathways. Viruses can also redirect lipids from host cell organelles; lipid exchange at membrane contact sites, where the membranes of adjacent organelles are in close apposition, has been implicated in the replication of several +RNA viruses. Here we review current understanding of DMV biogenesis. With a focus on the exploitation of contact site machinery by +RNA viruses to generate replication organelles, we discuss evidence that similar mechanisms support SARS-CoV-2 replication, protecting its RNA from the host cell immune response