Existence, blow-up and exponential decay estimates for a nonlinear wave equation with boundary conditions of two-point type

This paper is devoted to studying a nonlinear wave equation with boundary conditions of two-point type. First, we state two local existence theorems and under the suitable conditions, we prove that any weak solutions with negative initial energy will blow up in finite time. Next, we give a sufficient condition to guarantee the global existence and exponential decay of weak solutions. Finally, we present numerical results.     

Rapid and label-free detection of H5N1 virus using carbon nanotube network field effect transistor

DNA hybridization-based detection techniques are widely used in genetics, medicine, and drug discovery. However, the current techniques are usually based on labels and reagents that are time consuming and complex to implement. In this study, we report a label-free DNA sensor based on single-walled carbon nanotube field effect transistor (SWCNTFET) for selective DNA hybridization detection of H5N1 virus. A network of single-walled carbon nanotubes (SWCNTs) acts as the conductor channel. Probe DNA sequences were adsorbed onto SWCNTs. The developed DNA sensor can effectively detect full-complementary DNA with concentration as low as 1.25 pM. The sensitivity of the DNA sensor reached approximately 0.28 nM/nA. The effect of the parameters, including DNA probe concentration, its complementary concentration, mismatched sequence, and hybridization time, on the sensor response was also studied. The results showed the potential application of the DNA sensor for medical, environmental, and epidemic detection.     

Investigation of early antibiotic use in pediatric patients with acute respiratory infections by high-performance liquid chromatography

In this study, we developed and validated two reliable high-performance liquid chromatography (HPLC) methods for the qualitative detection of six oral β-lactams, which are commonly used in pediatric patients with acute respiratory infections (ARIs). Two distinct reverse-phase chromatographic separations of six β-lactams were obtained. Four β-lactams (cefadroxil, cephalexin, cefaclor and cefixime) in urine were separated using a gradient program with a mobile phase consisting of K₂HPO₄ buffer (20 mm , pH 2.8) and acetonitrile on a LichroCART 250 × 4.6 mm, Purospher STAR C₁₈ end-capped (5 μm) column. Two remained β-lactams (amoxicillin and cefuroxime) were analyzed using a gradient elution with the mobile phase containing K₂HPO₄ buffer (20 mm , pH 3.0) and acetonitrile on a LichroCart^® Purospher Star C₈ end-capped column (5 μm, 125 × 4.6 mm). Good linearity within the range of 0.3–30 μg/ml for cefadroxil, cephalexin, cefaclor and cefixime, and 0.2–20 μg/ml for amoxicillin and cefuroxime, was attained. The precisions were <14%. The accuracies ranged from 85.87 to 102.8%. The two validated methods were then applied to determine these six antibiotics in 553 urine samples of pediatric patients with ARIs. As a result, 32.2% were positive with one or more of six tested β-lactams. Cefixime was the most commonly detected agent, accounting for 9.8% of enrolled patients.     

Finite Morse Index Solutions of a Nonlinear Schrödinger Equation

Acta Mathematica Sinica, English Series - We prove Liouville type theorems for stable and finite Morse index H loc 1 ∩ L loc ∞ solutions of the nonlinear Schrödinger equation...     

Variation of radioactivity and trace metal elements during the growth period of water spinach

Journal of Radioanalytical and Nuclear Chemistry - Plants uptake and accumulate nutrient from the surrounding area in different amounts depending on the nutritional needs of plants in each...