Crystallization Behavior and Mechanical Properties of Microinjection Molded High Density Polyethylene Parts

Ultra-thin high density polyethylene (HDPE) parts with two different molecular weights were prepared by microinjection molding (MIM). The dependence of crystalline morphology and orientation, as well as the resulting mechanical properties of the samples, on molecular weight is described. The toughness of the high-molecular-weight (HMW) sample was over 2 times that of the low-molecular-weight (LMW) one, in parallel with a significant increase of tensile strength. Microstructure characterizations, including differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS), were performed to investigate the variations of the microstructure. It is suggested that the increased crystallinity and higher degree of both molecular and lamellar orientation were beneficial to the enhancement of strength of the HMW sample. SAXS results showed that a highly oriented crystalline structure, i.e. shish-kebabs, were formed in parts of both of the two HDPE. Furthermore, a larger number of shish and kebab structure or lamellae was formed in the HMW sample due to the fact that the crystallinity was increased and the lamellar thickness and lateral crystallite size was reduced. Therefore, a stronger physical cross-linking network was formed in the HMW sample because of the increased connection points, which was in favor of the notable improvement of toughness. We suggest this issue is of great significance for achieving materials with high performance by tailoring the microstructure.     

Radiolabeling and biological evaluation of 125I-Necitumumab for EGFR-targeted SPECT imaging

Journal of Radioanalytical and Nuclear Chemistry - Radiolabeled epidermal growth factor receptor (EGFR) targeted antibody could be used for imaging EGFR expressing cancer. In this study, the SPECT...     

Direct Protein Detection in Solutions of High Ionic Strength using Polyethylene Glycol-modified AlGaN/GaN High Electron Mobility Transistors

Herein, we proposed a simple 3-(aminopropyl) triethoxysilane/polyethylene glycol (APTES/PEG)-AlGaN/GaN high electron mobility transistors (HEMT) biosensor that enabled direct detection in high ionic strength solutions. Unlike previous modification strategies, the PEG-modified on the GaN surface established a stable screening system by forming a porous biopolymer layer, which can overcome Debye shielding. In our work, the APTES/PEG modification enabled immunoglobulin G (IgG) to be easily detected in solutions with concentrations of up to 30 mM (3x) of phosphate buffered saline (PBS), indicating that the APTES/PEG modification strategy had the potential for direct detection of biomolecules in physiological solutions, which provided a new method for bio-surface modification on GaN and advanced the practical application of AlGaN/GaN HEMT biosensors.     

Alternating direction and Taylor expansion minimization algorithms for unconstrained nuclear norm optimization

Numerical Algorithms - In the past decade, robust principal component analysis (RPCA) and low-rank matrix completion (LRMC), as two very important optimization problems with the view of recovering...     

Unusual peroxidase activity of a myoglobin mutant with two distal histidines

By retaining the native distal His64 in sperm whale myoglobin(Mb),a second distal histidine was engineered in Mb by mutating Leu29 to His29.The resultant mutant of L29H Mb exhibits an unusual enhanced peroxidase activity with a positive cooperativity in comparison to that of wild type Mb.The new enzyme with two cooperative distal histidines has not been found in native peroxidase, which emphasizes a creation of the rational protein design.     

Potential of Microalgae Carotenoids for Industrial Application

Applied Biochemistry and Biotechnology - Microalgae cultivation, when compared to the growth of higher plants, presents many advantages such as faster growth, higher biomass productivity, and...     

Low-energy isomer identification, structural evolution, and magnetic properties in manganese-doped gold clusters MnAu(n) (n = 1-16)

The size-dependent electronic, structural, and magnetic properties of Mn-doped gold clusters have been systematically investigated by using relativistic all-electron density functional theory with generalized gradient approximation. A number of new isomers are obtained for neutral MnAu(n) (n = 1-16) clusters to probe the structural evolution. The two-dimensional (2D) to three-dimensional (3D) transition occurs in the size range n = 7-10 with manifest structure competitions. From size n = 13 to n = 16, the MnAu(n) prefers a gold cage structure with Mn atom locating at the center. The relative stabilities of the ground-state MnAu(n) clusters show a pronounced odd-even oscillation with the number of Au atoms. The magnetic moments of MnAu(n) clusters vary from 3 μ(B) to 6 μ(B) with the different cluster size, suggesting that nonmagnetic Au(n) clusters can serve as a flexible host to tailor the dopant's magnetism, which has potential applications in new nanomaterials with tunable magnetic properties.