Preparation of Protein-like Silver–Cysteine Hybrid Nanowires and Application in Ultrasensitive Immunoassay of Cancer Biomarker

Novel protein-like silver–cysteine hybrid nanowires (<i>p</i>-SCNWs) have been synthesized by a green, simple, nontemplate, seedless, and one-step aqueous-phase approach. AgNO₃ and l-cysteine were dissolved in distilled water, forming Ag–cysteine precipitates and HNO₃. Under vigorous stirring, the pH of the solution was rapidly adjusted to 9.0 by addition of concentrated sodium hydroxide solution, leading to quick dissolution of the Ag-cysteine precipitates and sudden appearance of white precipitates of <i>p</i>-SCNWs. The <i>p</i>-SCNWs are monodispersed nanowires with diameter of 100 nm and length of tens of micrometers, and have abundant carboxyl (−COOH) and amine (−NH₂) groups at their surfaces, large amounts of peptide-linkages and S-bonding silver ions (Ag⁺) inside, making them look and act like Ag-hybrid protein nanostructures. The abundant −COOH and −NH₂ groups at the surfaces of <i>p</i>-SCNWs have been found to facilitate the reactions between the <i>p</i>-SCNWs and proteins including antibodies. Furthermore, the fact that the <i>p</i>-SCNWs contain large amounts of silver ions enables biofunctionalized <i>p</i>-SCNWs to be excellent signal amplifying chemiluminescence labels for ultrasensitive and highly selective detection of important antigens, such as cancer biomarkers. In this work, the immunoassay of carcinoembryonic antigen (CEA) in human serum was taken as an example to demonstrate the immunoassay applications of antibody-functionalized <i>p</i>-SCNWs. By the novel <i>p</i>-SCNW labels, CEA can be detected in the linear range from 5 to 400 fg/mL with a limit of detection (LOD) of 2.2 fg/mL (at signal-to-noise ratio of 3), which is much lower than that obtained by commercially available enzyme-linked immunosorbent assay (ELISA). Therefore, the synthesized <i>p</i>-SCNWs are envisioned to be an excellent carrier for proteins and related immunoassay strategy would have promising applications in ultrasensitive clinical screening of cancer biomarkers for early diagnostics of cancers

Chitosan-Stabilized Self-Assembled Fluorescent Gold Nanoclusters for Cell Imaging and Biodistribution in Vivo

Biocompatible, near-infrared luminescent gold nanoclusters were synthesized in situ using as-prepared chitosan grafted with N-acetyl-l-cysteine (NAC-CS). The fluorescent gold nanoclusters coated with chitosan-N-acetyl-l-cysteine (AuNCs@NAC-CS) were aggregated by multiple ultrasmall gold nanoclusters closing with each other, with strong fluorescence emission at 680 nm upon excitation at 360 nm. AuNCs@NAC-CS did not display any appreciable cytotoxicity on cells even at a concentration of 1.0 mg mL^–1. AuNCs@NAC-CS were more insensitive to H₂O₂ and trypsin compared with fluorescent gold nanoclusters coated with Albumin Bovine V (AuNCs@BSA), which make them have long time imaging in HeLa cells. Furthermore, the obvious fluorescence signal of AuNCs@NAC-CS appeared in the liver and kidney of the normal mice after 6 h injection. And the fluorescence intensity decreased after that because of the highly efficient clearance characteristics of ultrasmall nanoparticles. These findings demonstrated that AuNCs@NAC-CS possessed good fluorescence, low cytotoxicity, and low sensitivity to some content of cells, allowing imaging of the living cells

Desorption Mechanism of Asphaltenes in the Presence of Electrolyte and the Extended Derjaguin–Landau–Verwey–Overbeek Theory

Desorption of asphaltenes from silica-coated quartz crystals upon exposure to a series of saline solutions was studied through the measurements of quartz crystal microbalance with dissipation (QCM-D), atomic force microscopy (AFM), and contact angle. Interestingly, it was found that the mass loading and thickness of asphaltene film decreased during the injection of sodium chloride solution at the concentrations ranging from 1 to 10 mM, with the surface tending to be hydrophilic, whereas the mass loading and film thickness increased gradually when the concentration increased from 10 to 1000 mM, with the surface inclined to be hydrophobic. It was also found that the electrostatic force had a great effect on this process due to the interactions between the charged interfaces of oil/water and water/solid. Besides, some additional interactions may arise under small distance at the presence of the electrolyte solution, and therefore, a direct force-measuring technique was introduced, in which the functionalized AFM tips felt a solid surface to model the interactions among three phases of oil, water, and solid. Based on the computed results of disjoining pressure isotherms, the theory of Derjaguin–Landau–Verwey–Overbeek (DLVO) was extended, taking into account of the participation of hydration forces which played an important role at short range. These structural forces mostly originated from the overlap of the hydrated layers under a variety of salinity concentrations, resulting in the balance of resultant interactions

Juvenile Lifers and Juveniles in Michigan Prisons: A Population of Special Concern

Prisoners serving life without parole for offenses they committed when they were juveniles have received much attention after the United States Supreme Court found in Miller v Alabama that mandatory life without parole for juveniles violated the Eighth Amendment and found that its Miller decision applied retroactively. Courts have begun the process of sentencing and resentencing these individuals, some of whom are still teens and some of whom have served 40 years or more in the Michigan Department of Corrections (MDOC). All told, not including new cases that come before the court, approximately 370 prisoners will receive individualized sentences under the state laws enacted to implement Miller and Montgomery v Louisiana. This article examines a few ways in which federal and state corrections law and corrections policy affect this population

Histogram for Academic performance scores.

<p>Histogram for Academic performance scores.</p

Quantile regression estimates of VIPA.

<p>Y axes represent coefficient estimates of physical activities over the distribution of Academic performance scores; X axes indicates the quantiles of the dependent variable. The dashed line is the OLS estimate for physical activities and the dotted lines are the 95% confidence interval bounds. The shaded areas represent the 95% confidence intervals for the quantile regression estimates (100 bootstrap replications).</p

The associations between sleep duration and school performance at follow-up.

<p>The higher the score was, the more impaired the school performance was. Children’s gender, age, BMI, family income, family structure, and parents’ educational levels at follow-up were controlled.</p

The sample characteristics by groups at baseline (2007) and follow-up (2009) in the intervention trial (mean±SD unless indicated).

<p>SD: sleep duration; Family income was expressed in RMB(yuan)/person/month.</p>a<p>Analysis of Variance, ANOVA.</p>b<p>Chi-square Test.</p>*<p><i>p</i><0.05.</p>**<p><i>p</i><0.01.</p>***<p><i>p</i><0.001.</p

The association of sleep parameters with demographic and socioeconomic characteristics in the cross-sectional study (n = 20778).

<p>SD: sleep duration; Family income was expressed in RMB(yuan)/person/month.</p>a<p>Analysis of Variance, ANOVA.</p>b<p>Chi-square Test.</p>c<p>Independent-samples t test.</p>*<p><i>p</i><0.05.</p>**<p><i>p</i><0.01.</p>***<p><i>p</i><0.001.</p

The Associations of sleep duration and daytime sleepiness, at baseline and follow-up, with school performance at follow-up in the longitudinal cohort study, 2005–2009 (n = 612).

<p>The higher the score was, the more impaired the school performance was.</p><p>OR, odds ratio; CI, confidence interval.</p><p>Generalized Linear Models controlled by children’s gender, age, BMI, family income, family structure, and parents’ educational levels.</p