Hydrogels from dextran and soybean oil by UV photo‐polymerization

In this work, hydrogels were synthesized by UV photo‐polymerization of hydrophilic dextran functionalized with acrylate groups (Dex‐A) and hydrophobic acrylate epoxidized soybean oil (AESO). The acrylation of dextran was accomplished by reacting dextran (M_w 70,000 g mol^?1) with acryloyl chloride and pyridine. The Dex‐A was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Five rigid hydrogels were prepared using the weight ratios of Dex‐A and AESO as 10/90, 20/80, 30/70, 40/60, and 50/50. The hydrogels were characterized by FTIR, thermal gravimetric analyses (TGA) and scanning electronic microscopy (SEM). The experimental results demonstrated that the swelling and release profiles of the Dex‐A/AESO hydrogels can be tailored by varying the ratio of Dex‐A and AESO thus varying the balance of hydrophilicity and hydrophobicity of the network structures and the crosslinking density. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41446.     

Optical and Scintillation Properties of Ce3+‐Doped LuAG and YAG Transparent Ceramics: A Comparative Study

Cerium‐doped lutetium aluminum garnet (LuAG:Ce) and yttrium aluminum garnet (YAG:Ce) transparent ceramics of same dimension were fabricated and their optical and scintillation properties were studied. LuAG:Ce transparent ceramic showed higher light yield under UV and X‐ray excitation with respect to YAG:Ce transparent ceramic. YAG:Ce transparent ceramic showed higher light yield under gamma excitation and better energy resolution, which could be due to the considerable amount of slower emission (38.5%) in LuAG:Ce as well as lower optical transparency with respect to YAG:Ce ceramic.     

A wideband circularly polarized slot antenna with antipodal strips for WLAN and C‐band applications

A single‐fed circularly polarized square shaped wide slot antenna with modified ground plane and microstrip feed has been presented. The field in the slot is perturbed by introducing an antipodal strips section attached with a microstrip line to produce circular polarization in a wide band of frequencies. The antipodal strip section consists of a group of four strips of unequal length and separation. The presence of asymmetric perturbations in the slot is mainly responsible for exciting two orthogonal modes in the slot having equal magnitude and 90° phase difference which results in circular polarization. A wide bandwidth of 3.3 GHz (4.4 GHz‐7.7 GHz) has been achieved for an axial ratio value AR < 3 dB with the minimum axial ratio value being 0.3 dB. The impedance bandwidth for |S₁₁| < ?10 dB ranges from 4.3 GHz to 8 GHz, and therefore covers most of the C‐band communication systems. The antenna exhibits stable radiation patterns throughout the circular polarization bandwidth with a gain around 6 dBi in entire operational bandwidth. A prototype of antenna was fabricated and measured. The antenna has a planar size 0.40λ₀ × 0.40λ₀ and thickness of 0.02λ₀ where λ₀ is the wavelength in free space at the lowest frequency. With its compact size and low profile, the antenna is a favorable choice for WLAN (5.15‐5.85 GHz) and a wide variety of C‐band wireless applications.     

Implementation,calibration and accuracy testing of an image-enhanced endoscopy system

This paper presents a new method for image-guided surgery called image-enhanced endoscopy. Registered real and virtual endoscopic images (perspective volume renderings generated from the same view as the endoscope camera using a preoperative image) are displayed simultaneously; when combined with the ability to vary tissue transparency in the virtual images, this provides surgeons with the ability to see beyond visible surfaces and, thus, provides additional exposure during surgery. A mount with four photoreflective spheres is rigidly attached to the endoscope and its position and orientation is tracked using an optical position sensor. Generation of virtual images that are accurately registered to the real endoscopic images requires calibration of the tracked endoscope. The calibration process determines intrinsic parameters (that represent the projection of three-dimensional points onto the two-dimensional endoscope camera imaging plane) and extrinsic parameters (that represent the transformation from the coordinate system of the tracker mount attached to the endoscope to the coordinate system of the endoscope camera), and determines radial lens distortion. The calibration routine is fast, automatic, accurate and reliable, and is insensitive to rotational orientation of the endoscope. The routine automatically detects, localizes, and identifies dots in a video image snapshot of the calibration target grid and determines the calibration parameters from the sets of known physical coordinates and localized image coordinates of the target grid dots. Using nonlinear lens-distortion correction, which can be performed at real-time rates (30 frames per second), the mean projection error is less than 0.5 mm at distances up to 25 mm from the endoscope tip, and less than 1.0 mm up to 45 mm. Experimental measurements and point-based registration error theory show that the tracking error is about 0.5-0.7 mm at the tip of the endoscope and less than 0.9 mm for all points in the field of view of the endoscope camera at a distance of up to 65 mm from the tip. It is probable that much of the projection error is due to endoscope tracking error rather than calibration error. Two examples of clinical applications are presented to illustrate the usefulness of image-enhanced endoscopy. This method is a useful addition to conventional image-guidance systems, which generally show only the position of the tip (and sometimes the orientation) of a surgical instrument or probe on reformatted image slices.     

Quantum-based exact pattern matching algorithms for biological sequences

In computational biology, desired patterns are searched in large text databases, and an exact match is preferable. Classical benchmark algorithms obtain competent solutions for pattern matching in time, whereas quantum algorithm design is based on Grover's method, which completes the search in time. This paper briefly explains existing quantum algorithms and defines their processing limitations. Our initial work overcomes existing algorithmic constraints by proposing the quantum-based combined exact (QBCE) algorithm for the pattern-matching problem to process exact patterns. Next, quantum random access memory (QRAM) processing is discussed, and based on it, we propose the QRAM processing-based exact (QPBE) pattern-matching algorithm. We show that to find all occurrences of a pattern, the best case time complexities of the QBCE and QPBE algorithms are , and the exceptional worst case is bounded by . Thus, the proposed quantum algorithms achieve computational speedup. Our work is proved mathematically and validated with simulation, and complexity analysis demonstrates that our quantum algorithms are better than existing pattern-matching methods.     

Nanofibrous membrane-based absorption refrigeration system

This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature, and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved.     

Antioxidant activity of mulberry fruit extracts

Phenolic compounds were extracted from the fruits of Morus nigra and Morus alba using methanol and acetone. The sugar-free extracts (SFEs) were prepared using Amberlite XAD-16 column chromatography. All of the SFEs exhibited antioxidant potential as determined by ABTS (0.75-1.25 mmol Trolox/g), DPPH (2,2-diphenyl-1-picrylhydrazyl) (EC(50) from 48 μg/mL to 79 μg/mL), and reducing power assays. However, a stronger activity was noted for the SFEs obtained from Morus nigra fruits. These extracts also possessed the highest contents of total phenolics: 164 mg/g (methanolic SFE) and 173 mg/g (acetonic SFE). The presence of phenolic acids and flavonoids in the extracts was confirmed using HPLC method and chlorogenic acid and rutin were found as the dominant phenolic constituents in the SFEs.     

Effects of ammonium hydroxide on the structure and gas adsorption of nanosized Zr-MOFs (UiO-66)

Several zirconium-based metal-organic frameworks (Zr-MOFs) have been synthesized using ammonium hydroxide as an additive in the synthesis process. Their physicochemical properties have been characterized by N(2) adsorption/desorption, XRD, SEM, FTIR, and TGA, and their application in CO(2) adsorption was evaluated. It was found that addition of ammonium hydroxide produced some effects on the structure and adsorption behavior of Zr-MOFs. The pore size and pore volume of Zr-MOFs were enhanced with the additive, however, specific surface area of Zr-MOFs was reduced. Using an ammonium hydroxide additive, the crystal size of Zr-MOF was reduced with increasing amount of the additive. All the samples presented strong thermal stability. Adsorption tests showed that capacity of CO(2) adsorption on the Zr-MOFs under standard conditions was reduced due to decreased micropore fractions. However, modified Zr-MOFs had significantly lower adsorption heat. The adsorption capacity of carbon dioxide was increased at high pressure, reaching 8.63 mmol g(-1) at 987 kPa for Zr-MOF-NH(4)-2.