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Simulating the dielectric spectra of solvents requires the nuanced definition of inter- and intra-molecular forces. Non-polarizable force fields, while thoroughly benchmarked for dielectric applications, do not capture all the spectral features of solvents, such as water. Conversely, polarizable force fields have been largely untested in the context of dielectric spectroscopy but include charge and dipole fluctuations that contribute to intermolecular interactions. We benchmark non-polarizable force fields and the polarizable force fields AMOEBA03 and HIPPO for liquid water and find that the polarizable force fields can capture all the experimentally observed spectral features with varying degrees of accuracy. However, the non-polarizable force fields miss at least one peak. To diagnose this deficiency, we decompose the liquid water spectra from polarizable force fields at multiple temperatures into static and induced dipole contributions and find that the peak originates from induced dipole contributions. Broadening our inquiry to other solvents parameterized with the AMOEBA09 force field, we demonstrate good agreement between the experimental and simulated dielectric spectra of methanol and formamide. To produce these spectra, we develop a new computational approach to calculate the dielectric spectrum via the fluctuation dissipation theorem. This method minimizes the error in both the low and high frequency portions of the spectrum, improving the overall accuracy of the simulated spectrum and broadening the computed frequency range. [ABSTRACT FROM AUTHOR]

The article discusses the importance of understanding the atomic-scale structure and dynamics of solid-liquid interfaces in order to manipulate charge and drive chemical transformations. It highlights recent developments in computational and experimental techniques that provide detailed atomic pictures of these interfaces. The article also explores the impact of solid-liquid interfaces on crystal growth, biomolecule-cell interactions, and the design of composite materials for electromagnetic shielding. The authors emphasize the need for further development of techniques to bridge the atomic and macroscopic scales in order to fully exploit the potential of solid-liquid interfaces for technological applications. [Extracted from the article]

Controlling electrochemical reactivity requires a detailed understanding of the charging behavior and thermodynamics of the electrochemical interface. Experiments can independently probe the overall charge response of the electrochemical double layer by capacitance measurements and the thermodynamics of the inner layer with potential of maximum entropy measurements. Relating these properties by computational modeling of the electrochemical interface has so far been challenging due to the low accuracy of classical molecular dynamics (MD) for capacitance and the limited time and length scales of ab initio MD. Here, we combine large ensembles of long-time-scale classical MD simulations with charge response from electronic density functional theory to predict the potential-dependent capacitance of a family of ideal aqueous electrochemical interfaces with different peak capacitances. We show that while the potential of maximum capacitance varies, this entire family exhibits an electrode charge of maximum capacitance (CMC) between −2.9 and −2.2 μC/cm2, regardless of the details in the electronic response. Simulated heating of the same interfaces reveals that the entropy peaks at a charge of maximum entropy (CME) of −5.1 ± 0.6 μC/cm2, in agreement with experimental findings for metallic electrodes. The CME and CMC both indicate asymmetric response of interfacial water that is stronger for negatively charged electrodes, while the difference between CME and CMC illustrates the richness in behavior of even the ideal electrochemical interface. [ABSTRACT FROM AUTHOR]

Prior to 1955, when Morio Kasai first performed the hepatic portoenterostomy procedure which now bears his name, Biliary atresia (BA) was a uniformly fatal disease. Both the Kasai procedure and liver transplantation have markedly improved the outlook for infants with this condition. Although long-term survival with native liver occurs in the minority, survival rates post liver transplantation are high. Most young people born with BA will now survive into adulthood but their ongoing requirements for health care will necessitate their transition from a family-centred paediatric service to a patient-centred adult service. Despite a rapid growth in transition services over recent years and progress in transitional care, transition from paediatric to adult services is still a risk for poor clinical and psychosocial outcomes and increased health care costs. Adult hepatologists should be aware of the clinical management and complications of biliary atresia and the long-term consequences of liver transplantation in childhood. Survivors of childhood illness require a different approach to that for young adults presenting after 18 years of age with careful consideration of their emotional, social, and sexual health. They need to understand the risks of non-adherence, both for clinic appointments and medication, as well as the implications for graft loss. Developing adequate transitional care for these young people is based on effective collaboration at the paediatric–adult interface and is a major challenge for paediatric and adult providers alike in the 21st century. This entails education for patients and adult physicians in order to familiarise them with the long-term complications, in particular for those surviving with their native liver and the timing of consideration of liver transplantation if required. This article focusses on the outcome for children with biliary atresia who survive into adolescence and adult life with considerations on their current management and prognosis. [ABSTRACT FROM AUTHOR]

Liver damage in hepatitis B is immune driven and correlates with inflammatory markers in patient serum. There is no comparison of these markers to determine if inflammatory profiles are distinct to different types of liver damage across patients at different stages of disease. We measured 25 inflammatory markers in patients with acute hepatitis B and chronic hepatitis B with hepatitis B e antigen seroconversion and chronic patients stopping nucleoside analogue therapy. Myeloid markers dominated the inflammatory profile in all stages of hepatitis B. More inflammatory markers were detectable in chronic patients, including elevated concentrations of cytotoxic effectors Fas ligand, TRAIL, and TNF-α. [ABSTRACT FROM AUTHOR]

In those MD simulations, the NVT ensemble was erroneously applied to all atoms, including the frozen electrode atoms, instead of the electrolyte atoms alone. Electrode charge densities (41 curves on the left from blue for -16 C/cm2 to red for +16 C/cm2) for each of the charge models and placement schemes at z = 0 in Fig. The potential of maximum capacitance (PMC) varies from -0.09 to -0.22 V from the PZC across the family, but the charge of maximum capacitance (CMC, black squares) is constant at -3.7 C/cm2 in (a)-(c) and -3.3 C/cm2 in (d). [Extracted from the article]

The microscopic dielectric response is a key quantity for electronic materials such as organic semiconductors. Calculations of this response for molecular crystals are currently either expensive or rely on extreme simplifications such as multipole expansions which lack microscopic detail. We present an alternate approach using a microscopic analogue of the Clausius-Mossotti equation, which constructs the dielectric response of a crystal from an eigenvalue decomposition of the dielectric response of individual molecules. This method can potentially be used to examine the effects of defects, disorder, and surfaces on the dielectric properties of molecular solids. [ABSTRACT FROM AUTHOR]

Continuum solvation models enable electronic structure calculations of systems in liquid environments, but because of the large number of empirical parameters, they are limited to the class of systems in their fit set (typically organic molecules). Here, we derive a solvation model with no empirical parameters for the dielectric response by taking the linear response limit of a classical density functional for molecular liquids. This model directly incorporates the nonlocal dielectric response of the liquid using an angular momentum expansion, and with a single fit parameter for dispersion contributions it predicts solvation energies of neutral molecules with a RMS error of 1.3 kcal/mol in water and 0.8 kcal/mol in chloroform and carbon tetrachloride. We show that this model is more accurate for strongly polar and charged systems than previous solvation models because of the parameter-free electric response, and demonstrate its suitability for ab initio solvation, including self-consistent solvation in quantum Monte Carlo calculations. [ABSTRACT FROM AUTHOR]

Background: In chronic hepatitis B (CHB) viral infection, e antigen positivity (HBeAg+) is associated with high levels of viral replication and infectivity. Furthermore, HBeAg‐positive CHB is associated with a liver disease spectrum ranging from none to severe. Aim: To assess whether the level of circulating HBeAg is associated with different clinical presentations of HBeAg‐positive CHB. Methods: A cross‐sectional analysis was conducted among HBV mono‐infected participants enrolled in Hepatitis B Research Network (HBRN) cohorts to explore clinical and virological associations with quantitative HBeAg (qHBeAg). Results: Among 763 HBeAg+ participants (56% female; 85% Asian; median age 26 years), multivariable median regression modelling significantly associated qHBeAg with liver injury (inverse qHBeAg association with ALT p<.001 and APRI p<.001), and with both race and age (p=0.01). Among Asians, qHBeAg was inversely related to age; a relationship less clear among Blacks and Whites. Among Asians also, median qHBeAg levels were higher among those infected with HBV genotype C versus B (p<0.001), suggesting causal virologic differences. Across all races, median qHBeAg was higher in women (p=.01). Independent of sex, age, race and HBV genotype, qHBeAg was higher in participants with predominant wild‐type versus basal core promoter and/or precore 'stop' viral variants (p<0.001). Conclusion: Lower qHBeAg was observed among HBRN participants with the greatest degree of liver injury independent of demographics and HBV genotype. These data support longitudinal studies to examine the role of qHBeAg in modulating the host immune response and predicting the outcomes of chronic HBV infection. [ABSTRACT FROM AUTHOR]

The prevalence of concurrent HBsAg and anti‐HBs in plasma of persons with chronic hepatitis B virus (HBV) infection is variable and its clinical significance enigmatic. We examined the prevalence and clinical and virological features of concurrent HBsAg and anti‐HBs in children and adults with chronic HBV infection living in North America. A total of 1462 HBsAg positive participants in the Hepatitis B Research Network paediatric and adult cohorts were included (median age 41 (range 4‐80) years, 48% female, 11% white, 13% black, 73% Asians). Only 18 (1.2%) were found to be anti‐HBs positive (≥10 mIU/mL) at initial study evaluation. Distributions of sex, race, HBV genotype and ALT were similar between participants with and without concurrent anti‐HBs. Those who were anti‐HBs positive appeared to be older (median age 50 vs 41 years, P =.06), have lower platelet counts (median 197 vs 222 × 103/mm3, P =.07) and have higher prevalence of HBeAg (44% vs 26%, P =.10). They also had lower HBsAg levels (median 2.0 vs 3.5 log10 IU/mL, P =.02). Testing of follow‐up samples after a median of 4 years (range 1‐6) in 12 of the 18 participants with initial concurrent anti‐HBs showed anti‐HBs became undetectable in 6, decreased to <10 mIU/mL in 1 and remained positive in 5 participants. Two patients lost HBsAg during follow‐up. In conclusion, prevalence of concurrent HBsAg and anti‐HBs was low at 1.2%, with anti‐HBs disappearing in some during follow‐up, in this large cohort of racially diverse children and adults with chronic HBV infection living in North America. Presence of concurrent HBsAg and anti‐HBs did not identify a specific phenotype of chronic hepatitis B, nor did it appear to affect clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: We sought to identify factors that are associated with LOS following pediatric (<18 years) liver transplantation in order to provide personalized counseling and discharge planning for recipients and their families. Methods: We identified 2726 infants (≤24 months) and 3210 children (>24 months) who underwent pediatric liver‐only transplantation from 2002‐2017 using the Scientific Registry of Transplant Recipients. We used multilevel multivariable negative binomial regression to analyze associations between LOS and recipient and donor characteristics and calculated the MLOSR to quantify heterogeneity in LOS across centers. Results: In infants, the median LOS (IQR) was 19 (13‐32) days. Hospitalization prior to transplant (ICU ratio:1.461.591.70; non‐ICU ratio:1.081.161.23), public insurance (ratio:1.031.091.15), and a segmental graft (ratio:1.081.151.22) were associated with a longer LOS; thus, we would expect a 1.59‐fold longer LOS in an infant admitted to the ICU compared to a non‐hospitalized infant with similar characteristics. In children, the median LOS (IQR) was 13 (9‐21) days. Hospitalization prior to transplant (ICU ratio:1.491.621.77; non‐ICU ratio:1.341.441.56), public insurance (ratio:1.021.071.13), a segmental graft (ratio:1.201.271.35), a living donor graft (ratio:1.271.381.51), and obesity (ratio:1.031.101.17) were associated with a longer LOS. The MLOSR was 1.25 in infants and 1.26 in children, meaning if an infant received a transplant at another center with a longer LOS, we would expect a 1.25‐fold difference in LOS driven by center practices alone. Conclusions: While center‐level practices account for substantial variation in LOS, consideration of donor and recipient factors can help clinicians provide more personalized counseling for families of pediatric liver transplant candidates. [ABSTRACT FROM AUTHOR]

Chronic hepatitis C certainly is a global health burden in children as well as in adults. Spontaneous viral clearance can occur in early childhood but is uncommon thereafter. Although the majority of cases are asymptomatic during childhood and young adulthood, without an effective treatment, children who acquire HCV via vertical transmission can develop chronic liver disease and other complications including end‐stage liver disease and hepatocellular carcinoma in adulthood. Efforts from worldwide health organizations, the pharmaceutical industry, and clinical and research institutions have resulted in very effective interferon‐free therapy with direct‐acting antiviral agents (DAAs) for HCV‐infected children. In this manuscript, we will briefly review the epidemiology of HCV in children, historic treatment, current published data on DAAs in children and conclude with suggestions for management of the child with HCV in the era of DAAs. [ABSTRACT FROM AUTHOR]

Hepatitis B e antigen (HBeAg) is an important serological marker of hepatitis B virus (HBV) infection and is associated with higher levels of viraemia, increased risk of infectivity to others and increased risk of hepatocellular carcinoma. We analysed HBeAg status in a large cohort of adults and children enrolled in Cohort Studies of the Hepatitis B Research Network, long‐term natural history studies of chronic HBV infection. A cross‐sectional analysis examined factors associated with HBeAg positivity, including demographic and virologic data, across the age spectrum. Among 2241 enrolled participants who met criteria for this analysis, 825 (37%) were seropositive for HBeAg. The prevalence of HBeAg was lower in those with older age, ranging from 85% among those up to 10 years of age to only 12% among those older than 50 years. In addition to age, both race and HBV genotype were independently associated with HBeAg positivity. There was a significant interaction between age and race; the prevalence of HBeAg was significantly higher among Asians > 10‐30 years old vs Whites or Blacks who were >10 to 30 years old and those infected with HBV genotype C. Conversely, the presence of the basal core promoter and precore variants was associated with significantly lower prevalence of HBeAg, even when adjusted for age, race and genotype. These data will provide a better understanding of factors associated with seropositivity for HBeAg and may lead to better strategies for preventing HBV infection and broader indications for antiviral therapy. [ABSTRACT FROM AUTHOR]

A comparative analysis of whole genome sequencing (WGS) and genotype calling was initiated for ten human genome samples sequenced by St. Petersburg State University Peterhof Sequencing Center and by three commercial sequencing centers outside of Russia. The sequence quality, efficiency of DNA variant and genotype calling were compared with each other and with DNA microarrays for each of ten study subjects. We assessed calling of SNPs, indels, copy number variation, and the speed of WGS throughput promised. Twenty separate QC analyses showed high similarities among the sequence quality and called genotypes. The ten genomes tested by the centers included eight American patients afflicted with autoimmune hepatitis (AIH), plus one case’s unaffected parents, in a prelude to discovering genetic influences in this rare disease of unknown etiology. The detailed internal replication and parallel analyses allowed the observation of two of eight AIH cases carrying a rare allele genotype for a previously described AIH-associated gene (FTCD), plus multiple occurrences of known HLA-DRB1 alleles associated with AIH (HLA-DRB1-03:01:01, 13:01:01 and 7:01:01). We also list putative SNVs in other genes as suggestive in AIH influence. [ABSTRACT FROM AUTHOR]

Aim: The etiopathogenesis of non‐syndromic biliary atresia (BA) is obscure. The primary aim was to investigate intrahepatic bile duct cilia (IHBC) in BA at diagnosis and its correlation with clinical outcome. The secondary aim was to analyze IHBC in routine paraffin‐embedded liver biopsies using conventional scanning electron microscopy (SEM). Methods: Surgical liver biopsies taken at diagnosis from 22 BA infants (age range, 39–116 days) and from eight children with non‐BA chronic cholestasis (age range, 162 days −16.8 years) were evaluated for IHBC by immunofluorescence (IF) and SEM. A minimum 18‐month follow‐up after surgery was available for all patients. Results: By IF, cilia were present in 6/8 (75%) non‐BA but only in 3/22 (14%) BA cases, and cilia were reduced or absent in 19/22 (86%) BA and 2/8 (25%) non‐BA livers (P < 0.01). In BA, cilia presence was found to be associated with clearance of jaundice at 6‐month follow‐up (P < 0.05). However, high overall survival rates with native liver, >90% at 12 months, and >70% at 24 months post‐surgery, were recorded regardless of cilia presence/absence at diagnosis. Electron microscopy was able to detect bile ducts and cilia in routine liver biopsies, revealing significant abnormalities in 100% BA livers. Conclusions: The presence of IHBC in BA livers at the diagnosis was associated with resolution of cholestasis, although was not predictive of short‐term survival with native liver. Scanning electron microscopy represents a powerful new tool to study routine liver biopsies in biliary disorders. Cilia dysfunction in BA pathogenesis and/or disease progression warrants further investigation. [ABSTRACT FROM AUTHOR]

The successful deployment of advanced energy-conversion systems depends critically on our understanding of the fundamental interactions of the key adsorbed intermediates (hydrogen *H and hydroxyl *OH) at electrified metal-aqueous electrolyte interfaces. The effect of alkali metal cations (Li+, Na+, K+, Cs+) on the non-Nernstian pH shift of the step-related voltammetric peak of the Pt(553) electrode is investigated over a wide pH window (1 to 13) by means of experimental and computational methods. The co-adsorbed alkali cations along the step weaken the OH adsorption at the step sites, causing a positive shift of the potential of the step-related peak on Pt(553). Density functional calculations explain the observations on the identity and concentration of alkali cations on the non-Nernstian pH shift, and demonstrate that cation-hydroxyl co-adsorption causes the apparent pH dependence of 'hydrogen' adsorption in the step sites of platinum electrodes. [ABSTRACT FROM AUTHOR]

The successful deployment of advanced energy-conversion systems depends critically on our understanding of the fundamental interactions of the key adsorbed intermediates (hydrogen *H and hydroxyl *OH) at electrified metal-aqueous electrolyte interfaces. The effect of alkali metal cations (Li+, Na+, K+, Cs+) on the non-Nernstian pH shift of the step-related voltammetric peak of the Pt(553) electrode is investigated over a wide pH window (1 to 13) by means of experimental and computational methods. The co-adsorbed alkali cations along the step weaken the OH adsorption at the step sites, causing a positive shift of the potential of the step-related peak on Pt(553). Density functional calculations explain the observations on the identity and concentration of alkali cations on the non-Nernstian pH shift, and demonstrate that cation-hydroxyl co-adsorption causes the apparent pH dependence of 'hydrogen' adsorption in the step sites of platinum electrodes. [ABSTRACT FROM AUTHOR]

Introduction: Optimizing outcome in biliary atresia (BA) requires timely diagnosis. Cholestasis is a presenting feature of BA, as well as other diagnoses (Non-BA). Identification of clinical features of neonatal cholestasis that would expedite decisions to pursue subsequent invasive testing to correctly diagnose or exclude BA would enhance outcomes. The analytical goal was to develop a predictive model for BA using data available at initial presentation. Methods: Infants at presentation with neonatal cholestasis (direct/conjugated bilirubin >2 mg/dl [34.2 μM]) were enrolled prior to surgical exploration in a prospective observational multi-centered study (PROBE–NCT00061828). Clinical features (physical findings, laboratory results, gallbladder sonography) at enrollment were analyzed. Initially, 19 features were selected as candidate predictors. Two approaches were used to build models for diagnosis prediction: a hierarchical classification and regression decision tree (CART) and a logistic regression model using a stepwise selection strategy. Results: In PROBE April 2004-February 2014, 401 infants met criteria for BA and 259 for Non-BA. Univariate analysis identified 13 features that were significantly different between BA and Non-BA. Using a CART predictive model of BA versus Non-BA (significant factors: gamma-glutamyl transpeptidase, acholic stools, weight), the receiver operating characteristic area under the curve (ROC AUC) was 0.83. Twelve percent of BA infants were misclassified as Non-BA; 17% of Non-BA infants were misclassified as BA. Stepwise logistic regression identified seven factors in a predictive model (ROC AUC 0.89). Using this model, a predicted probability of >0.8 (n = 357) yielded an 81% true positive rate for BA; <0.2 (n = 120) yielded an 11% false negative rate. Conclusion: Despite the relatively good accuracy of our optimized prediction models, the high precision required for differentiating BA from Non-BA was not achieved. Accurate identification of BA in infants with neonatal cholestasis requires further evaluation, and BA should not be excluded based only on presenting clinical features. [ABSTRACT FROM AUTHOR]