Ti3AlC2 coated D-shaped fiber saturable absorber for Q-switched pulse generation

In this letter, a titanium aluminum carbide (Ti3AlC2) coated D-shaped fiber is proposed and demonstrated as a new saturable absorber (SA) for Q-switched laser pulse generation. In preparing the SA, the Ti3AlC2 powder is dispersed in liquid polyvinyl alcohol (PVA) before the solution is dropped and left to dry onto a polished surface of D-shape fiber. The SA is added to an erbium-doped fiber laser (EDFL) cavity to modulate the cavity loss for Q-switching. The Q-switched laser is obtained at 1 561 nm. The pulse width of the pulses can be varied between 7.4 µs and 5.1 µs with a corresponding repetition rate range from 41.26 kHz to 54.35 kHz, when the pump power is increased from 42.2 mW to 71.5 mW. At 71.5 mW pump, the pulse energy is obtained at 70.3 nJ. The signal-to-noise ratio (SNR) of the fundamental frequency is recorded at 67 dB, which indicates the stability of the laser.     

Colloid Transport through Natural Filter Media

In this project the use of natural media filtration (NMF) was evaluated for its ability to remove colloidal particles from the aqueous phase as a function of ionic strength and filter media type by determining first-order kinetic deposition rate coefficients. Mushroom compost (MC) and leaf compost (LC) were tested as natural filter media and the results were compared to those obtained using sand and granular activated carbon (GAC). The highest deposition rate coefficients were observed for GAC, followed by LC and MC, and the lowest deposition rate coefficients were found for sand. As predicted by the Derjaguin–Landau–Verwey–Overbeek theory, higher deposition rates were obtained at higher solution ionic strengths. Overall the experiments suggest that the NMF process can efficiently remove colloidal particles from surface waters.     

Sustained release of tetracycline from polymeric periodontal inserts prepared by extrusion

The specific aim of this study was to prepare polymeric inserts containing tetracycline that are intended for intraperiodontal pocket application. The inserts were prepared by a simple extrusion method and based on mixtures of polyvinyl alcohol, glyceryl behenate, xanthan gum, carrageenan, hydroxypropyl methylcellulose, and hyaluronic acid in addition to tetracycline HCL. The inserts were characterized regarding average weight, diameter, water content, and average tetracycline content. Zero‐order release kinetics of tetracycline were observed in case of three of the four batches of the prepared inserts with release profiles that were essentially similar. The release of the drug was incomplete in all cases. This was due, as shown by the equilibrium dialysis tests, to tetracycline binding by the polymers. However, the inserts performed more than 7 days drug sustained release which indicates promising results for local delivery of tetracycline for treatment of periodontal disease. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Formulation and release of doxycycline HCL from an ion activated in situ gelling delivery system for the treatment of periodontal disease

This study reports on the formulation of doxycycline HCL in an ion activated in situ gelling delivery system and its implications for the treatment of periodontal disease. The system is based on the use of alginate as the gelling agent and hydroxypropyl methylcellulose (HPMC) as a viscosity enhancing agent. The ion activated gelling mechanism in this system is based on the concept of interaction with the divalent calcium ions present in the gingival crevicular fluid (GCF). The gelling capacity of the prepared formulations was assessed visually and by investigating their rheological behavior upon mixing with human blood serum since it has the same composition as the GCF. The rheological behavior of all formulations was not affected by incorporation of the drug. In vitro release studies showed that the alginate/HPMC mixture, upon gelling after mixing with serum, can sustain the release of doxycycline HCL for an extended period of time which was more than 12 days. These results indicated that this system can be used as an in situ gelling local delivery system for the treatment of periodontal disease. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A generalized modular redundancy scheme for enhancing fault tolerance of combinational circuits

Nano-scale devices are continuously shrinking, operating at lower voltages and higher frequencies. This makes them more susceptible to environmental perturbations and distinguished by their high dynamic fault rates. Redundancy techniques are widely used to increase the reliability of combinational logic circuits. In this work, soft error reliability is improved by using such techniques, and based on probability of occurrence for combinations at the outputs of circuits. A generalized modular redundancy scheme to enhance the reliability of combinational circuits is proposed. Additionally, several aspects regarding the application of this scheme are explored. This comprises types of redundant modules, complexity of voters and single versus multiple outputs protection. Also, a methodology for applying the generalized modular redundancy scheme is developed. Reliability analysis for various benchmarks from the LGSynth91 suite shows that the proposed methodology can achieve reliability figures higher than that of triple modular redundancy. In general, significant overhead savings are accomplished in addition to that superior reliability.     

The origin of androgen and estrogen in a virilized postmenopausal woman with bilateral benign cystic teratomas

Clitoromegaly was observed in a 73-year-old woman who had bilateral ovarian benign cystic teratomas that contained only epithelial derivatives. Scattered in the stroma of these ovaries were clusters of hyperplastic cells. The plasma testosterone production rate was 2.4 mg/day, a value that is ten times greater than that of normal postmenopausal women. The elevated plasma concentrations of testosterone and androstenedione decreased to normal by the second day after bilateral oophorectomy. Ovarian venous concentrations of testosterone and androstenedione were also increased and were considerably greater than those in peripheral blood. Estrone production was 68 microng/day, most of which could be accounted fo by the extraglandular formation from androstenedione. Estradiol production was 71 microng/day, of which 75% was computed to arise from extraglandular formation and the remainder likely arose by ovarian secretion. The modest increase in estrogen production was associated with slight cystic hyperplasia of the endometrium. From this study we conclude that the hyperplastic ovarian stroma was the source of the excessive androgen production.     

A technique to quantify morphological damage of the flute profile in the midplane of corrugated fibreboard

This research presents a technique to quantify morphological damage to flutes in corrugated fibreboard (CFB). The method involves laser cutting thin samples and analysing digital images of the flute profiles. The surface profiles of creased CFB before and after laser cutting were measured using fringe projection and showed that the sample preparation does not significantly affect the flute profile. After imaging the laser cut samples, skeleton analysis was used to derive a digitised profile of the flute shape. To characterise the level of damage to the flute profile, a similarity factor (SF) was introduced to quantify the relative difference between test sample and reference flute profiles. Validation of this analysis technique was done by generating known images of flute profile with variations that include distortions that could occur to CFB. These images were then fed into the skeleton analysis, and the results were compared with the original profile. This comparison showed good agreement between the initial and skeleton‐analysed flutes. A demonstration of the skeleton analysis on purposefully damaged actual CFB flute profiles shows that the SF reduces as the level of crushing increases, showing that the technique could be used to enumerate morphological damage to CFB during manufacture, conversion, and use.     

Egocentric visual scene description based on human-object interaction and deep spatial relations among objects

Multimedia Tools and Applications - Visual Scene interpretation is one of the major areas of research in the recent past. Recognition of human object interaction is a fundamental step...