Band Rejections for WLAN and WIMAX Utilizing UWB Planar Antenna by Slits in the Conductor Elements

Band rejections for WLAN and WIMAX frequency bandwidths are realized in a UWB planar antenna utilizing a single slit in an elliptical element. WLAN and WIMAX communication system frequency bandwidths have been known to coexist with the UWB frequency bandwidth. Coexistence of multiple frequency bandwidths are susceptible to disadvantage and could cause interferences to other communication system. The disadvantages could be in form of signal disruption, data loss and equipment malfunctions [1-3]. Thus, it is essential to eliminate WLAN frequency bandwidth from the UWB communication system. Slits are employed to influence the exterior current distribution on the radiator and therefore, has generated mismatched of the input impedance. The phenomenon has caused the band notch characteristic and thus, rejected the frequency bandwidths for 5 to 6 and 3.3 to 3.7GHz, respectively. The structures of the slits are simple in a compact design of the UWB planar antenna. The UWB planar antennas with band rejections are compared with the reference antenna. The reflection coefficients S11 for the designed UWB planar antennas have rejected the frequency bandwidths for 5 to 6 and 3.3 to 3.7GHz, consecutively. The peak of the notched-band reflection coefficient S11 for the frequency bandwidths 5 to 6 and 3.3 to 3.7GHz are about -3 and -4dB, respectively. Surface currents are distributed in the slit areas. The radiation patterns are illustrated for the frequency 3.5, 7.5 and 9.5GHz for the single notched-band, while 4.5, 7.5 and 9.5GHz for the dual notched-band characteristics. Radiation patterns for the single and dual notched-band in the H- and E-planes for the designed antennas are in omni- and bi-directional, respectively. Maximum gains G are in the –z and –x direction in the H- and E- plane, for the UWB planar antenna with single and dual notched-band characteristics

Characterizing Passively Q-switched Fiber Laser in LiDAR Application

A LiDAR system consists of a Q-switched fiber laser that emits light pulses to measure the distance from the target. We have experimentally demonstrated a passively Q-switched erbium-doped fiber laser (EDFL) by employing graphene saturable absorber (SA). The SA was prepared by dipping a polyvinyl alcohol (PVA) thin film into the graphene solution. Once the SA was fabricated, it can be placed in the cavity to perform pulses and it is operating at 1558.92 nm. The shortest pulse received is 3.9 µs and generated at the repetition rate of 115 kHz. The pulses are stable between pump powers of 59.6mW and 127.1 mW. At the maximum pump power value of 127.1 mW, The laser cavity produced pulses with a 1.4mW output power and a 1.1nJ pulse energy

Improvement of phytase properties by rational design intended for animal feed

For application in animal feed, a phytase of interest must have high activity in the broad range prevalent industrial condition and in digestive tract of the animal. The present investigation describes approaches to rationally engineer a phytase with better activity profiles. Computer modelling is used to identify and examine active site of phyFAUIA1 phytase. The factors influencing the ligand binding strength in the active site is analyzed and computational site directed mutagenesis experiments were carried out to evaluate the effects of mutations on the binding strength before and after mutation. From the directive results of computational studies, point mutation was introduced by site directed mutagenesis using polymerase chain reaction (PCR). Mutagenesis is achieved by two steps PCR procedure. Four primers were designed and synthesized: two primers contain mutation at the point of interest which is complement to each other and the other two primers were designed for unique restriction sites. Several numbers of single, double as well as triple mutations have been introduced in phyFAUIA1 gene, and the mutant enzymes will be characterized and compared to computational results

Characterizing Passively Q-switched Fiber Laser in LiDAR Application

A LiDAR system consists of a Q-switched fiber laser that emits light pulses to measure the distance from the target. We have experimentally demonstrated a passively Q-switched erbium-doped fiber laser (EDFL) by employing graphene saturable absorber (SA). The SA was prepared by dipping a polyvinyl alcohol (PVA) thin film into the graphene solution. Once the SA was fabricated, it can be placed in the cavity to perform pulses and it is operating at 1558.92 nm. The shortest pulse received is 3.9 µs and generated at the repetition rate of 115 kHz. The pulses are stable between pump powers of 59.6mW and 127.1 mW. At the maximum pump power value of 127.1 mW, The laser cavity produced pulses with a 1.4mW output power and a 1.1nJ pulse energy

Recombinant bromelain production in Escherichia coli: process optimization in shake flask culture by response surface methodology

Bromelain, a cysteine protease with various therapeutic and industrial applications, was expressed in Escherichia coli, BL21-AI clone, under different cultivation conditions (post-induction temperature, L-arabinose concentration and post-induction period). The optimized conditions by response surface methodology using face centered central composite design were 0.2% (w/v) L-arabinose, 8 hr and 25°C. The analysis of variance coupled with larger value of R2 (0.989) showed that the quadratic model used for the prediction was highly significant (p < 0.05). Under the optimized conditions, the model produced bromelain activity of 9.2 U/mg while validation experiments gave bromelain activity of 9.6 ± 0.02 U/mg at 0.15% (w/v) L-arabinose, 8 hr and 27°C. This study had innovatively developed cultivation conditions for better production of recombinant bromelain in shake flask culture

Optimization of spray drying process conditions for recombinant stem bromelain

Bromelain is a plant protease with numerous therapeutic, industrial and analytical applications. Spray drying of enzyme often leads to loss of enzymatic activity arising from thermal denaturation. Hence, the design of a suitable drying process should provide a great level of active enzyme. The present study examined the effect of operating parameters of a laboratory spray dryer on powder characteristics, so as to optimize the production of recombinant bromelain expressed in E. coli BL 21-AI. The recombinant enzyme was spray dried from maltodextrin (10 %w/v), CaCl2 (0.2 % w/v) and sodium metabisulphite (2.5 % w/v) solutions using a laboratory-scale Büchi Mini Spray dryer B-290. The process parameters investigated were: drying air inlet temperature (100-120 ºC), drying air volumetric flow rate – given as % of the maximum aspiration rate (80-100 %), feed volumetric flow rate– expressed as % of the maximum pump rate (10-15 %). On the other hand, the activity of bromelain (U/ml) served as the response of the design. Outlet temperature was maintained at 50 oC. All the studied process parameters had significantly affected the characteristics of the powdered bromelain, at a 95% confidence interval. The higher values of coefficient of determination (R2 = 99.95% and adjusted R2 = 99.84%) attained, showed that there is good compliance between the experimental and the theoretical values predicted by the model. Moreover, the graphical representations of the regression equation generated suggested that the examined independent variables interacted significantly. Thus, the corroboration of reality of the optimal conditions and the validity of the model had been ascertained. Consequently, under optimized process conditions, the study had produced powdered bromelain with greater quality in terms of moisture contents, residual activity and product recovery

A v-shape optical pin interface for board level optical interconnect

This paper introduces a new interface of an optical pin for Printed Circuit Boards (PCBs), the V-shape cut type which is an innovation from the 90-degree cut type of optical pin. The effectiveness is determined by optical characteristics through OptiCAD and by experiment. The simulation used a model of ray tracing analysis which is a one to two (split) connection function model. For the experiment, a Polymer Optical Fibre (POF) V-shape optical pin has been fabricated. It was found that the V-shaped optical pin has a multi-branched function and is applicable to optical interconnection

Recovery of recombinant bromelain from Escherichia coli BL21-AI

In spite of the fact that commercial bromelain supplements are available in the market, to date, none of them are produced and formulated from recombinant forms. They are extracted and purified (often partially) from the stem and fruit of pineapple (Ananas comosus). This makes the production of bromelain very difficult, less reliable, often contaminated and expensive. In this study, a recombinant bromelain was expressed as soluble (active) and insoluble (inactive) enzyme in Escherichia coli BL21-A1. The enzyme fractions were purified using Ni-NTA His•Bind resin with the aid of an automated fast protein liquid chromatography (FPLC) system. Purification fold and percentage yield of the purified active bromelain were found to be 3.7 and 64%, respectively. SDS-PAGE results showed that the enzyme was purified to near homogeneity and the soluble form exhibited a single band with molecular weight of about 45 kDa

Heterologous expression of Bromelain in Escherichia coli

In spite of the fact that commercial bromelain supplements are available in the market, to date, none of them are produced and formulated from recombinant forms. They are extracted and purified (often partially) from the stem and fruit of pineapple. This makes the production of bromelain very difficult, less reliable, often contaminated and expensive. In this study, a recombinant bromelain from BL21 A clone was expressed as soluble and insoluble active enzyme. Maximum activity was observed at 4-hour post induction with 0.2% L-arabinose and over 60% of the enzyme was found to be expressed in soluble form. The enzyme fractions were purified using Nickel-NTA spin column. Purification fold and % yield of the purified lysate were found to be 35 and 75% respectively. SDS-PAGE results showed that the purified bromelain exhibited a single band with molecular weight of about 45kDa

Performance Improvement for Hybrid L-band Remote Erbium Doped Fiber Amplifier/Raman using Phase Modulator

We have demonstrated the performance improvement of L-band hybrid remote Erbium-doped fiber amplifier by introducing a phase modulator to suppress the stimulated Brilloiun scattering (SBS) effect in the transmission. The transmission gain has improved by 12.65dB while the noise figure has reduced by 47.1dB when 0dBm signal power is generated at 1590.05nm wavelength. Furthermore, the optical signal-to-noise ratio has improved from 7.81dB to 29.72dB when the signal power is varied from -30dBm to 0dBm. By implementing a phase modulator to the input signal somehow able to produce better performance regarding gain, noise figure and optical signal-to-noise ratio, especially at the higher signal power as the gain, has been transferred to the Stokes signal and the amplified signal