Effect of infusion on fluoride concentration in various chinese tea

The fluoride content in infusions of commercially available black tea, oolong tea, green tea, white tea and bata tea was determined via fluoride ion selective electrode method. Two methods of infusion were carried out: continuous infusion and repeated infusion. In continuous infusion, black tea yielded the highest concentration of fluoride, which ranged between 0.929±0.053 mg/L and 3.746±0.028 mg/L. Fluoride detected in brick tea ranged from 1.099±0.046 mg/L to 2.398±0.006 mg/L. The dissolvable fluoride for oolong tea, green tea, and white tea were ranged from 0.584±0.080 mg/L to 1.255±0.044 mg/L, 0.624±0.088 mg/L to 1.838±0.062 mg/L and 0.571±0.027 mg/L to 1.845±0.017 mg/L, respectively. The cumulative fluoride contents in repeated infusion were higher than those prepared by continuous infusion for all types of tea. Results of the study indicate that there was a wide range of fluoride content with different types of tea and methods of infusion. Because excessive intake of fluoride can cause dental and skeletal fluorosis, it is necessary for the government or international organization to establish a standard of fluoride content in tea commodities in order to protect the consumers against health hazards

Systematic review of the effects of bisphosphonates on bone density and fracture incidence in childhood acute lymphoblastic leukaemia

Skeletal fragility is a common complication of childhood acute lymphoblastic leukaemia (ALL) but the impact of bisphosphonate therapy on bone mass and fracture is unclear. We aim to conduct a systematic review to evaluate the effects of bisphosphonates on bone mineral density (BMD) and fracture incidence in children with ALL. EMBASE, Medline and the Cochrane Library were thoroughly searched by two researchers. Inclusion criteria was any child under the age of 18 years with a diagnosis of ALL, who had received any bisphosphonate treatment and had serial measurements of bone density performed thereafter. All primary research studies of any study design, excluding case reports, were included. Ten full text papers were identified with two exclusively meeting the inclusion criteria. Both studies administered bisphosphonates to children receiving maintenance chemotherapy for varying durations. Bone density was assessed at regular intervals by dual x-ray absorptiometry (DXA). The majority of participants had an improvement in bone density at the end of each study. However, no size adjustment of DXA data was performed. Limited information on fracture occurrence was provided by one study but did not include routine screening for vertebral fractures. This systematic review identified that there is insufficient evidence to support routine use of prophylactic bisphosphonate therapy in childhood ALL for prevention of fracture and improvement of bone mass. Future well-designed clinical trials in those at highest risk of fractures in ALL are now needed

Demonstration of fundamental mode only propagation in highly multimode fibre for high power EDFAs

The use of short lengths of large core phosphate glass fibre, doped with high concentrations of Er or Er:Yb represents an attractive route to achieving high power erbium doped fibre amplifiers (EDFAs) and lasers (EDFLs). With the aim of investigating the potential of achieving diffraction limited output from such large core fibres, we present experimental results of fundamental mode propagation through a 20 cm length of passive 300 micrometer core multimode fibre when the input is a well-aligned Gaussian beam. Through careful control of fibre geometry, input beam parameters and alignment, we measured an output M squared of 1.1 + - 0.05. The fibre had a numerical aperture of 0.389, implying a V number of 236.8. To our knowledge, this is the largest core fibre through which diffraction limited fundamental mode propagation has been demonstrated. Although the results presented here relate to undoped fibre, they do provide the practical basis for a new generation of EDFAs and EDFLs.Comment: 5 figure

Ballistic Performance of Coconut Shell Powder/Twaron Fabricagainst Non-armour Piercing Projectiles

Body armour technologists over the years are seeking to develop protective systems whichare both effective and lightweight. However these hard armour materials are very expensive andhave certain weight constraints. From this point of view, natural fibres and fillers have attractedthe attention of researchers due to their low density with high specific strengths, abundance,availability, renewability and being environmental-friendly. This paper reports the potential useof coconut shell powder-epoxy composite (COEX) panel bonded with Twaron CT716 fabric asa hard armour material and the characteristics of its fracture imprints from a specific threat levelwhen subjected to ballistic tests1 (NIJ Standard 0108.01). It was observed that the imprint patternson the particulate composite (COEX) could be identified according to effectiveness in impactenergy dissipation. COEX/Twaron test panel was found to withstand impact equivalent to NIJLevel IIIA using 9 mm FMJ ammunition but perforated at NIJ Level III of 7.62 mm FMJ bulletimpacts. Test results showed that COEX panel do possess shock absorbance characteristics andcan be utilised as  an armour component in the hard-body armour system. Dependency onTwaron fabric layers as ballistic reinforcements has been reduced up to 3-time with 170 per centimprovement on energy-absorption capabilities when using COEX composite as the frontalcomponent of the armour

Adaptive Impedance Tuning Network using Genetic Algorithm: ITuneGA

Adaptive impedance tuning algorithms are used to preserve the link quality of mobile phones under fluctuating user conditions. It is highly desirable to correct the complex impedance mismatch with high convergence rate. Presented here, is a novel technique for correcting impedance mismatch in adaptive impedance tuning network by exploiting the relationships among the genetic algorithm’s coefficient values derived from the matching network parameters. Simulation results demonstrate that the proposed impedance tunable algorithm (ITuneGA) outperforms conventional GA and LMS, with its fast convergence speed and high accuracy. The robustness of ITuneGA has been verified by using Pi-networks with two and four tuning elements. ITuneGA corrects antenna impedance mismatches and reduces the reflected power, thereby significantly improving the quality of the signal

Dickson Charge Pump Rectifier using Ultra-Low Power (ULP) Diode for BAN Applications

High power consumption and small battery size severely limit the operating time of devices in Body Area Network (BAN). Radio Frequency (RF) harvesting system can be one of the ways to solve this constraint. Rectifier converts ambient RF into direct current (DC). In a conventional rectifier circuit, Schottky diodes have been considered as an attractive candidate due to their low forward voltage drop and fast switching speed. However, Schottky diodes are not properly modelled in Complementary Metal Oxide Semiconductor (CMOS) technologies which restrict their usefulness in low -cost applications, where high integration levels are desired. Thus, an efficient model of Schottky diode in an integrated circuit (IC) domain is needed. For this reason, Ultra-Low Power (ULP) diode has been proposed in the IC rectifier designs. The performance of ULP diode was compared with diode-connected MOSFET based on Dickson topology and Villard voltage multiplier in 130nm Silterra process technology. The correlation of the design parameters to the performance of voltage rectifier was analysed. The results show that the efficiency of the voltage multiplier has successfully increased more than double based on the optimisation of the design parameters

Cosmological Implications of Neutrinos

The lectures describe several cosmological effects produced by neutrinos. Upper and lower cosmological limits on neutrino mass are derived. The role that neutrinos may play in formation of large scale structure of the universe is described and neutrino mass limits are presented. Effects of neutrinos on cosmological background radiation and on big bang nucleosynthesis are discussed. Limits on the number of neutrino flavors and mass/mixing are given.Comment: 41 page, 7 figures; lectures presented at ITEP Winter School, February, 2002; to be published in the Proceeding

Interacting one dimensional electron gas with open boundaries

We discuss the properties of interacting electrons on a finite chain with open boundary conditions. We extend the Haldane Luttinger liquid description to these systems and study how the presence of the boundaries modifies various correlation functions. In view of possible experimental applications to quantum wires, we analyse how tunneling measurements can reveal the underlying Luttinger liquid properties. The two terminal conductance is calculated. We also point out possible applications to quasi one dimensional materials and study the effects of magnetic impurities.Comment: 38 pages, ReVTeX, 7 figures (available upon request