Nanoimprint Lithography for Functional Three‐Dimensional Patterns

Nanoimprint lithography (NIL) is viewed as an alternative nanopatterning technique to traditional photolithography, allowing micrometer‐scale and sub‐hundred‐nanometer resolution as well as three‐dimensional structure fabrication. In this Research News article we highlight current activities towards the use of NIL in patterning active or functional materials, and the application of NIL in patterning materials that present both chemistry and structure/topo­graphy in the patterned structures, which provide scaffolds for subsequent manipulation. We discuss and give examples of the various materials and chemistries that have been used to create functional patterns and their implication in various fields as electronic and magnetic devices, optically relevant structures, biologically important surfaces, and 3D particles.     

Effect of Attapulgite filler on the properties of Nylon‐6

Nylon‐6/Attapulgite (ATP) composites were prepared by melt blending in a twin screw extruder. Nylon‐6/ATP composites were tested for its mechanical, rheological, thermal and morphological properties. The results have shown drastic improvement in the flexural modulus by 74% at the loading level of 4% of ATP. The tensile strength was also increased at the 3–4% loadings of ATP. The impact strength was doubled even at the 2% loading of ATP. The strength and stiffness of Nylon‐6/ATP composites were both improved significantly in the presence of attapulgite. In addition, the incorporation of ATP gave rise to the increase in the storage modulus. The extensional viscosities were studied and found to increase as the loading level was increased. Scanning electron microscopy (SEM) was used to assess the clay morphology and the dispersion of the attapulgite. SEM revealed the addition of attapulgite showed fibrillar structure of Nylon‐6/ATP composite. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

An Overview of Near Infrared Spectroscopy and Its Applications in the Detection of Genetically Modified Organisms

Near-infrared spectroscopy (NIRS) has become a more popular approach for quantitative and qualitative analysis of feeds, foods and medicine in conjunction with an arsenal of chemometric tools. This was the foundation for the increased importance of NIRS in other fields, like genetics and transgenic monitoring. A considerable number of studies have utilized NIRS for the effective identification and discrimination of plants and foods, especially for the identification of genetically modified crops. Few previous reviews have elaborated on the applications of NIRS in agriculture and food, but there is no comprehensive review that compares the use of NIRS in the detection of genetically modified organisms (GMOs). This is particularly important because, in comparison to previous technologies such as PCR and ELISA, NIRS offers several advantages, such as speed (eliminating time-consuming procedures), non-destructive/non-invasive analysis, and is inexpensive in terms of cost and maintenance. More importantly, this technique has the potential to measure multiple quality components in GMOs with reliable accuracy. In this review, we brief about the fundamentals and versatile applications of NIRS for the effective identification of GMOs in the agricultural and food systems.     

Structure–property relationship of blocked diisocyanates: synthesis of polyimides using imidazole‐blocked isocyanates

Imidazole, 2‐methylimidazole and benzimidazole‐blocked aromatic and aliphatic diisocyanates have been prepared and polymerized with pyromellitic dianhydride in the presence of a basic catalyst. The polymers are characterized with FTIR, ¹H NMR and ¹³C NMR spectroscopy and GPC, DSC and TGA. The structure–property relationship of blocked diisocyanates are discussed in terms of molecular weight of the polyimides obtained. Considering the blocking agent, GPC results show that the benzimidazole blocked adduct yields higher molecular weight polymer than the 2‐methylimidazole‐blocked adduct which, in turn, yields higher molecular weight polymer than the imidazole‐blocked adduct. Considering the structure of the isocyanate, the molecular weight of polymer increases from isophorone diisocyanate to hexamethylene diisocyanate and to toluene diisocyanate (TDI). DSC traces of the polymers derived from TDI show glass transitions (T_g) in the temperature range 152–180 °C and the values increase from the polymer based on imidazole‐blocked TDI to 2‐methylimidazole‐blocked TDI and to benzimidazole‐blocked TDI. © 2000 Society of Chemical Industry     

The Pichia pastoris dihydroxyacetone kinase is a PTS1-containing,but cytosolic,protein that is essential for growth on methanol

Dihydroxyacetone kinase (DAK) is essential for methanol assimilation in methylotrophic yeasts. We have cloned the DAK gene from Pichia pastoris by functional complementation of a mutant that was unable to grow on methanol. An open reading frame of 1824 bp was identified that encodes a 65·3 kDa protein with high homology to DAK from Saccharomyces cerevisiae. Although DAK from P. pastoris contained a C-terminal tripeptide, TKL, which we showed can act as a peroxisomal targeting signal when fused to the green fluorescent protein, the enzyme was primarily cytosolic. The TKL tripeptide was not required for the biochemical function of DAK because a deletion construct lacking the DNA encoding this tripeptide was able to complement the P. pastoris dakΔ mutant. Peroxisomes, which are essential for growth of P. pastoris on methanol, were present in the dakΔ mutant and the import of peroxisomal proteins was not disturbed. The dakΔ mutant grew at normal rates on glycerol and oleate media. However, unlike the wild-type cells, the dakΔ mutant was unable to grow on methanol as the sole carbon source but was able to grow on dihydroxyacetone at a much slower rate. The metabolic pathway explaining the reduced growth rate of the dakΔ mutant on dihydroxyacetone is discussed. The nucleotide sequence reported in this paper has been submitted to GenBank with Accession Number AF019198. © 1998 John Wiley & Sons, Ltd.     

Exponential filtering technique for Euclidean norm-regularized extreme learning machines

Pattern Analysis and Applications - Extreme Learning Machine (ELM) is a feedforward neural network that utilizes a single hidden layer to effectively tackle the learning speed challenges commonly...     

Influence of Cu Layer on Structural and Optical Properties of Copper Oxides Prepared as Stacks

Copper-layered copper oxide (CO) stacks were prepared. The X-ray diffraction (XRD) results showed polycrystalline nature and combination of mixed Cu₄O₃, CuO, Cu₂O, and Cu₈O phases with different orientations and also exhibited the growth of Cu₄O₃ phases when Cu layer coated over and sandwiched between copper oxides. The structural parameters pointed the influence of Cu layer on crystallite size, residual stress, microstrain, and dislocation density of the copper oxides with various stack configurations. In Cu₄O₃ phase, the crystallite size was high for Cu as base layer and low for Cu as interface between copper oxides. In addition, for the Cu₄O₃ phase, CO stacks showed low tensile stress than Cu layered CO stacks, and it was low for CuO phases in Cu layered CO stacks. Optical bandgaps were between 1.53 and 2.29 eV. CO/Cu stack prepared at room temperature and Cu/CO/Cu stack prepared at 573 K (300 °C) showed low and high bandgap values, respectively. Overall, the Cu layer influenced the structural parameters as well as the optical properties of CO stacks.