Uniform asymptotics for the tail probability of weighted sums with heavy tails

This paper studies the tail probability of weighted sums of the form $\sum_{i=1}^n c_i X_i$, where random variables $X_i$'s are either independent or pairwise quasi-asymptotical independent with heavy tails. Using $h$-insensitive function, the uniform asymptotic equivalence of the tail probabilities of $\sum_{i=1}^n c_iX_i$, $\max_{1\le k\le n}\sum_{i=1}^k c_iX_i$ and $\sum_{i=1}^n c_iX_i^+$ is established, where $X_i$'s are independent and follow the long-tailed distribution, and $c_i$'s take value in a broad interval. Some further uniform asymptotic results for the weighted sums of $X_i$'s with dominated varying tails are obtained. An application to the ruin probability in a discrete-time insurance risk model is presented

Uniform Asymptotics For the Tail Probability of Weighted Sums With Heavy Tails

This paper studies the tail probability of weighted sums of the form ∑i=1nciXi, where random variables X i\u27s are either independent or pairwise quasi-asymptotically independent with heavy tails. Using the idea of uniform long-tailedness, the uniform asymptotic equivalence of the tail probabilities of ∑i=1nciXi, max1≤k≤n∑i=1kciXi and ∑i=1nciXi+ is established, where X i\u27s are independent and follow the long-tailed distribution, and c i\u27s take value in a broad interval. Some further uniform asymptotic results for the weighted sums of X i\u27s with dominated varying tails are obtained. An application to the ruin probability in a discrete-time insurance risk model is presented. © 2014 Elsevier B.V

Development and Evaluation of Silica-Based Lectin Microcolumns for Glycoform Analysis of Alpha1-Acid Glycoprotein

Silica-based lectin microcolumns were developed and optimized for the separation and analysis of glycoform fractions in alpha1-acid glycoprotein (AGP) based on both the degree of branching and level of fucosylation. Concanavalin A (Con A) and Aleuria Aurantia lectin (AAL) were immobilized onto HPLC-grade silica by reductive amination and packed into 2.1 mm i.d. × 5.0 cm microcolumns. Factors examined for these microcolumns include their protein content, binding capacity, binding strength and band-broadening under isocratic conditions (Con A) or step elution conditions (AAL) and in the presence of various flow rates or temperatures. These factors were examined by using experiments based on frontal analysis, zonal elution, peak profiling and peak decay analysis. Up to 200 μg AGP could be loaded onto a Con A microcolumn and provide linear elution conditions, and 100 μg AGP could be applied to an AAL microcolumn. The final conditions for separating retained and non-retained AGP glycoform fractions on a Con A microcolumn used a flow rate of 50 μL min−1 and a temperature of 50 °C, which gave a separation of these fractions within 20 min or less. The final conditions for an AAL microcolumn included a flow rate of 0.75 mL min−1, a temperature of 50 °C, and the use of 2.0 mM L-fucose as a competing agent for elution, giving a separation of non-retained and retained AGP glycoforms in 6 min or less. The inter-day precisions were ± 0.7–4.0% or less for the retention times of the AGP glycoforms and ± 2.2–3.0% or less for their peak areas

Glycoform Analysis of Alpha1-Acid Glycoprotein by Capillary Electrophoresis Using Electrophoretic Injection

Human alpha1-acid glycoprotein (AGP) is an acute phase glycoprotein that has a heterogeneous glycosylation pattern. This pattern can change in certain diseases, which has resulted in interest in using AGP glycoforms as potential biomarkers for these diseases. This report describes a method that uses capillary electrophoresis to characterize and analyze AGP glycoforms both in purified samples of AGP and in human serum. This method uses static and dynamic coatings of poly (ethylene oxide) that are applied to a silica capillary for separation of AGP glycoforms in the reversed-polarity mode of CE and in the presence of negligible electroosmotic flow. Electrophoretic injection is performed onto such capillaries by using a stationary stacking interface between the sample and running buffer. In addition, acidic precipitation and desalting are used to allow for the isolation and the analysis of AGP from only 65 μL of serum. Up to eleven AGP glycoform bands can be reproducibly separated by this method, with the difference in migration time between neighboring bands being 12- to almost 60-fold larger than the standard deviation for the migration time of any given band. A limit of detection down to about 2 nM per glycoform band can be obtained by this method for AGP in serum based on absorbance detection and without the need for further sample modification or labeling

Optical Force and Torque on a Graphene-Coated Gold Nanosphere by a Vector Bessel Beam

In the framework of the generalized Lorenz–Mie theory (GLMT), the optical force and torque on a graphene-coated gold nanosphere by a vector Bessel beam are investigated. The core of the particle is gold, whose dielectric function is given by the Drude–Sommerfeld model, and the coating is multilayer graphene with layer number N, whose dielectric function is described by the Lorentz–Drude model. The axial optical force [Formula: see text] and torque [Formula: see text] are numerically analyzed, and the effects of the layer number N, wavelength [Formula: see text] , and beam parameters (half-cone angle [Formula: see text] , polarization, and order l) are mainly discussed. Numerical results show that the optical force and torque peaks can be adjusted by increasing the thickness of the graphene coating, and can not be adjusted by changing [Formula: see text] and l. However, [Formula: see text] and l can change the magnitude of the optical force and torque. The numerical results have potential applications involving the trapped graphene-coated gold nanosphere

Natural selection favoring more transmissible HIV detected in United States molecular transmission network.

HIV molecular epidemiology can identify clusters of individuals with elevated rates of HIV transmission. These variable transmission rates are primarily driven by host risk behavior; however, the effect of viral traits on variable transmission rates is poorly understood. Viral load, the concentration of HIV in blood, is a heritable viral trait that influences HIV infectiousness and disease progression. Here, we reconstruct HIV genetic transmission clusters using data from the United States National HIV Surveillance System and report that viruses in clusters, inferred to be frequently transmitted, have higher viral loads at diagnosis. Further, viral load is higher in people in larger clusters and with increased network connectivity, suggesting that HIV in the United States is experiencing natural selection to be more infectious and virulent. We also observe a concurrent increase in viral load at diagnosis over the last decade. This evolutionary trajectory may be slowed by prevention strategies prioritized toward rapidly growing transmission clusters

Clinical and pharmaceutical applications of affinity ligands in capillary electrophoresis: A review

Affinity capillary electrophoresis (ACE) is a separation technique that combines a biologically-related binding agent with the separating power and efficiency of capillary electrophoresis. This review will examine several classes of binding agents that have been used in ACE and applications that have been described for the resulting methods in clinical or pharmaceutical analysis. Binding agents that will be considered are antibodies, aptamers, lectins, serum proteins, carbohydrates, and enzymes. This review will also describe the various formats in which each type of binding agent has been used in CE, including both homogeneous and heterogeneous methods. Specific areas of applications that will be considered are CE-based immunoassays, glycoprotein/glycan separations, chiral separations, and biointeraction studies. The general principles and formats of ACE for each of these applications will be examined, along with the potential advantages or limitations of these methods

Genome-wide identification of new reference genes for RT-qPCR normalization in CGMMV-infected Lagenaria siceraria

Lagenaria siceraria is an economically important cucurbitaceous crop, but suitable reference genes (RGs) to use when the plants are infected by cucumber green mottle mosaic virus (CGMMV) have not been determined. Sixteen candidate RGs of both leaf and fruit and 18 candidate RGs mostly from separate RNA-Seq datasets of bottle gourd leaf or fruit were screened and assessed by RT-qPCR. The expression stability of these genes was determined and ranked using geNorm, NormFinder, BestKeeper and RefFinder. Comprehensive analysis resulted in the selection of LsCYP, LsH3, and LsTBP as the optimal RGs for bottle gourd leaves, and LsP4H, LsADP, and LsTBP for fruits. LsWD, LsGAPDH, and LsH3 were optimal for use in both leaves and fruits under the infection of CGMMV. Isopentenyl transferase (IPT) and DNA-directed RNA polymerase (DdRP) were used to validate the applicability of the most stable identified RGs from bottle gourd in response to CGMMV. All the candidate RGs performed in RT-qPCR consistently with the data from the transcriptome database. The results demonstrated that LsWD, LsGAPDH and LsH3 were the most suitable internal RGs for the leaf, and LsH3, LsGAPDH, LsP4H and LsCYP for the fruit