Stable Aqueous Nanoparticle Film Assemblies with Covalent and Charged Polymer Linking Networks

The construction of highly stable and efficiently assembled multilayer films of purely water soluble gold nanoparticles is reported. Citrate-stabilized nanoparticles (CS-NPs) of average core diameter of 10 nm are used as templates for stabilization-based exchange reactions with thioctic acid to form more robust aqueous NPs that can be assembled into multilayer films. The thioctic acid stabilized nanoparticles (TAS-NPs) are networked via covalent and electrostatic linking systems, employing dithiols and the cationic polymer poly(l-lysine), respectively. Multilayer films of up to 150 nm in thickness are successfully grown at biological pH with no observable degradation of the NPs within the film. The characteristic surface plasmon band, an optical feature of certain NP film assemblies that can be used to report the local environment and core spacing within the film, is preserved. Growth dynamics and film stability in solution and in the air are examined, with poly(l-lysine) linked films showing no evidence of aggregation for at least 50 days. We believe these films represent a pivotal step toward exploring the potential of aqueous NP film assemblies as a sensing apparatus

Polyelectrolyte-Linked Film Assemblies of Nanoparticles and Nanoshells: Growth, Stability, and Optical Properties

Multi-layer films of nanoparticles and nanoshells featuring various polymeric linkage molecules have been assembled and their optical properties characterized. The growth dynamics, including molecular weight effects, and stability of the various nanoparticle film constructions, using both single polymer as well as combinations of alternating charge polyelectrolytes as linking mechanisms, are presented. The polymeric linkers studied include poly-L-lysine, poly-L-arginine, poly(allylamine hydrochloride), and polyamidoamine dendrimers. Significantly air stable films were achieved with the use of multi-layered polymeric bridges between the nanoparticles and nanoshells. Optical sensitivity normally observed with these nanomaterials in solution was observed for their corresponding film geometries, with the nanoshell films exhibiting a markedly higher ability to report their local dielectric environment

SAPHIRE 8 Volume 2 - Technical Reference

The Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE) refers to a set of computer programs that were developed to create and analyze probabilistic risk assessment (PRAs). Herein information is provided on the principles used in the construction and operation of Version 8.0 of the SAPHIRE system. This report summarizes the fundamental mathematical concepts of sets and logic, fault trees, and probability. This volume then describes the algorithms used to construct a fault tree and to obtain the minimal cut sets. It gives the formulas used to obtain the probability of the top event from the minimal cut sets, and the formulas for probabilities that apply for various assumptions concerning reparability and mission time. It defines the measures of basic event importance that SAPHIRE can calculate. This volume gives an overview of uncertainty analysis using simple Monte Carlo sampling or Latin Hypercube sampling, and states the algorithms used by this program to generate random basic event probabilities from various distributions. Also covered are enhance capabilities such as seismic analysis, Workspace algorithms, cut set "recovery," end state manipulation, and use of "compound events.

Using light scattering to evaluate the separation of polydisperse nanoparticles

Appendix A Supplementary data The following are the supplementary data related to this article: Download Appendix A Supplementary data Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.aca.2015.06.027. Abstract The analysis of natural and otherwise complex samples is challenging and yields uncertainty about the accuracy and precision of measurements. Here we present a practical tool to assess relative accuracy among separation protocols for techniques using light scattering detection. Due to the highly non-linear relationship between particle size and the intensity of scattered light, a few large particles may obfuscate greater numbers of small particles. Therefore, insufficiently separated mixtures may result in an overestimate of the average measured particle size. Complete separation of complex samples is needed to mitigate this challenge. A separation protocol can be considered improved if the average measured size is smaller than a previous separation protocol. Further, the protocol resulting in the smallest average measured particle size yields the best separation among those explored. If the differential in average measured size between protocols is less than the measurement uncertainty, then the selected protocols are of equivalent precision. As a demonstration, this assessment metric is applied to optimization of cross flow (V x ) protocols in asymmetric flow field flow fractionation (AF4) separation interfaced with online quasi-elastic light scattering (QELS) detection using mixtures of polystyrene beads spanning a large size range. Using this assessment metric, the V x parameter was modulated to improve separation until the average measured size of the mixture was in statistical agreement with the calculated average size of particles in the mixture. While we demonstrate this metric by improving AF4V x protocols, it can be applied to any given separation parameters for separation techniques that employ dynamic light scattering detectors. Graphical abstract Highlights • We present a tool to assess relative accuracy among separation protocols. • This metric can be applied to any techniques using light scattering detection. • An improved separation protocol minimizes the average measured particle size. • A protocol with the smallest average measured particle size is the best separation. • Metric is demonstrated by improving AF4 cross flow protocols for polystyrene beads

Subacute ruminal acidosis reduces sperm quality in beef bulls

Breeding bulls are commonly fed high-energy diets, which may induce subacute ruminal acidosis (SARA). In this experiment, 8 Santa Gertrudis bulls (age 20 ± 6 mo) were used to evaluate the extent and duration of effects of SARA on semen quality and the associated changes in circulating hormones and metabolites. The bulls were relocated and fed in yards with unrestricted access to hay and daily individual concentrate feeding for 125 d before SARA challenge. Semen was collected and assessed at 14-d intervals before the challenge to ensure acclimatization and the attainment of a stable spermiogram. The challenge treatments consisted of either a single oral dose of oligofructose (OFF; 6.5 g/kg BW) or an equivalent sham dose of water (Control). Locomotion, behavior, respiratory rate, and cardiovascular and gastrointestinal function were intensively monitored during the 24-h challenge period. Rumen fluid samples were retained for VFA, ammonia, and lactate analysis. After the challenge, semen was then collected every third day for a period of 7 wk and then once weekly until 12 wk, with associated blood collection for FSH, testosterone, inhibin, and cortisol assay. Percent normal sperm decreased in bulls dosed with OFF after the challenge period (P < 0.05) and continued to remain lower on completion of the study at 88 d after challenge. There was a corresponding increase in sperm defects commencing from 16 d after challenge. These included proximal cytoplasmic droplets (P < 0.001), distal reflex midpieces (P = 0.01), and vacuole and teratoid heads (P < 0.001). Changes in semen quality after challenge were associated with lower serum testosterone (P < 0.001) and FSH (P < 0.05). Serum cortisol in OFF bulls tended to be greater (P = 0.07) at 7 d after challenge. This study shows that SARA challenge causes a reduction in sperm quality sufficient to preclude bulls from sale as single sire breeding animals 3 mo after the event occurred

Long-term risks and benefits associated with cesarean delivery for mother, baby, and subsequent pregnancies: Systematic review and meta-analysis

BACKGROUND:Cesarean birth rates continue to rise worldwide with recent (2016) reported rates of 24.5% in Western Europe, 32% in North America, and 41% in South America. The objective of this systematic review is to describe the long-term risks and benefits of cesarean delivery for mother, baby, and subsequent pregnancies. The primary maternal outcome was pelvic floor dysfunction, the primary baby outcome was asthma, and the primary subsequent pregnancy outcome was perinatal death. METHODS AND FINDINGS:Medline, Embase, Cochrane, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases were systematically searched for published studies in human subjects (last search 25 May 2017), supplemented by manual searches. Included studies were randomized controlled trials (RCTs) and large (more than 1,000 participants) prospective cohort studies with greater than or equal to one-year follow-up comparing outcomes of women delivering by cesarean delivery and by vaginal delivery. Two assessors screened 30,327 abstracts. Studies were graded for risk of bias by two assessors using the Scottish Intercollegiate Guideline Network (SIGN) Methodology Checklist and the Risk of Bias Assessment tool for Non-Randomized Studies. Results were pooled in fixed effects meta-analyses or in random effects models when significant heterogeneity was present (I2 ≥ 40%). One RCT and 79 cohort studies (all from high income countries) were included, involving 29,928,274 participants. Compared to vaginal delivery, cesarean delivery was associated with decreased risk of urinary incontinence, odds ratio (OR) 0.56 (95% CI 0.47 to 0.66; n = 58,900; 8 studies) and pelvic organ prolapse (OR 0.29, 0.17 to 0.51; n = 39,208; 2 studies). Children delivered by cesarean delivery had increased risk of asthma up to the age of 12 years (OR 1.21, 1.11 to 1.32; n = 887,960; 13 studies) and obesity up to the age of 5 years (OR 1.59, 1.33 to 1.90; n = 64,113; 6 studies). Pregnancy after cesarean delivery was associated with increased risk of miscarriage (OR 1.17, 1.03 to 1.32; n = 151,412; 4 studies) and stillbirth (OR 1.27, 1.15 to 1.40; n = 703,562; 8 studies), but not perinatal mortality (OR 1.11, 0.89 to 1.39; n = 91,429; 2 studies). Pregnancy following cesarean delivery was associated with increased risk of placenta previa (OR 1.74, 1.62 to 1.87; n = 7,101,692; 10 studies), placenta accreta (OR 2.95, 1.32 to 6.60; n = 705,108; 3 studies), and placental abruption (OR 1.38, 1.27 to 1.49; n = 5,667,160; 6 studies). This is a comprehensive review adhering to a registered protocol, and guidelines for the Meta-analysis of Observational Studies in Epidemiology were followed, but it is based on predominantly observational data, and in some meta-analyses, between-study heterogeneity is high; therefore, causation cannot be inferred and the results should be interpreted with caution. CONCLUSIONS:When compared with vaginal delivery, cesarean delivery is associated with a reduced rate of urinary incontinence and pelvic organ prolapse, but this should be weighed against the association with increased risks for fertility, future pregnancy, and long-term childhood outcomes. This information could be valuable in counselling women on mode of delivery

Effects of Graded Levels of Sorghum Wet Distiller’s Grains and Degraded Intake Protein Supply on Performance and Carcass Characteristics of Feedlot Cattle Fed Steam-Flaked Corn-Based Diets

Two experiments evaluated different levels of sorghum wet distiller’s grains plus solubles (SWDG) and effects of increasing the degraded intake protein (DIP) concentration in diets containing SWDG on performance and carcass characteristics of feedlot cattle. In Exp. 1, 200 beef steers (average BW = 404 kg) were fed increasing levels of SWDG (0, 5, 10, and 15% of DM) and one level of corn wet distiller’s grains plus solubles (10% of DM), which replaced steamflaked corn in a high-concentrate diet. Final BW (P = 0.04) and overall ADG (P = 0.01) decreased linearly with increasing levels of SWDG. Increasing SWDG decreased overall G:F (P = 0.01), hot carcass weight (P \u3c 0.01), and LM area (P \u3c 0.01). No differences were observed in overall DMI (P = 0.15) or other carcass characteristics (P ≥ 0.09). Neither DMI nor G:F differed between corn wet distiller’s grains plus solubles and SWDG when fed as 10% of the dietary DM. In Exp. 2, 200 steers (average BW = 369 kg) were either fed a control diet without SWDG (8.4% DIP) or three 10% SWDG diets with no urea added or urea added at either 50% or 100% of the difference in the DIP concentration between the diet with no urea added and control diets. Final BW (P = 0.03), overall ADG (P = 0.04), and overall G:F (P = 0.05) were greater for cattle fed the control diet. A linear decrease was observed in overall DMI with increasing DIP (P = 0.02). Likewise, overall ADG decreased with increasing DIP (P = 0.08). Cattle fed the control diet had greater hot carcass weight (P = 0.03), fat thickness (P = 0.02), and yield grade (P = 0.01) than the average of those fed the 3 SWDG diets. Results from both experiments suggest decreased performance and carcass value with increasing levels of SWDG alone or combined with additional DIP. At 10% of the dietary DM, corn and sorghum wet distiller’s grains resulted in similar ADG and G:F