Indistinguishable Encoding for Bidirectional Quantum Key Distribution: Theory to Experiment

We present for the first time, a bidirectional Quantum Key Distribution protocol with minimal encoding operations derived from the use of two `nonorthogonal' unitary transformations selected from two mutually unbiased unitary bases; which are indistinguishable in principle for a single use. Along with its decoding procedure, it is a stark contrast to its `orthogonal encoding' predecessors. Defining a more relevant notion of security threshold for such protocols, the current protocol outperforms its predecessor in terms of security as the maximal amount of information an eavesdropper can glean is essentially limited by the indistinguishability of the transformations. We further propose adaptations for a practical scenario and report on a proof of concept experimental scheme based on polarised photons from an attenuated pulsed laser for qubits, demonstrating the feasibility of such a protocol.Comment: 9 pages, 3 figure

Blind encoding into qudits

We consider the problem of encoding classical information into unknown qudit states belonging to any basis, of a maximal set of mutually unbiased bases, by one party and then decoding by another party who has perfect knowledge of the basis. Working with qudits of prime dimensions, we point out a no-go theorem that forbids shift operations on arbitrary unknown states. We then provide the necessary conditions for reliable encoding/decoding.Comment: To appear in Physics Letters

ACUTE AND SUB-ACUTE DERMAL TOXICITY STUDIES OF MORINDA CITRIFOLIA L. FRUIT EXTRACT IN SPRAGUE DAWLEY RATS

 Objective: Morinda citrifolia is one of the most significant plants that are used in traditional medicine. However, details of the dermal toxicity of M.citrifolia are still undiscovered. The objective of this study is to investigate the in vivo acute and subacute dermal toxicity of ethanolic extract of M.citrifolia fruit extract at doses 2000 and 5000 mg/kg in acute and 500, 1000 and 2000 mg/kg body weight in rats.Methods: In acute experiment, a total of 40 female rats were divided into eight groups, each group had five rats, and a total of 66 male rats weredivided into 11 groups of six rats in sub-acute experiment.Results: The extract at a single dose of 2000 and 5000 mg/kg of body weight did not produce treatment-related signs of toxicity or mortality inany of the animals tested during the 14-day observation period. In the repeated dose 28-day study, the application of 500, 1000 and 2000 mg/kg ofbody weight/day of fruit extract revealed no significant change (p>0.05) in bodyweight, hematological and biochemical parameters compared withthe control group. Similarly, grosspathology and histopathology examinations of liver, spleen, kidneys, and skin did not reveal any morphologicalalteration.Conclusion: Overall, the results recommend that the close application of M. citrifolia fruit extract did not deliver any critically dangerous impact inrats. Subsequently, the concentrate can be employed for pharmaceutical plans.Keywords: Morinda citrifolia, Acute dermal toxicity, Fruit extract, Sub-acute dermal toxicit

Gender Dependence in Mouth Opening Dimensions in Normal Adult Malaysians Population

While measurement of mouth opening is an important clinica examination in diagnosis and management of oral disease, data on non-Western populations are limited. This study was therefore conducted to determine the range of mouth opening in normal Malaysian male and female adults. A total of 34 dental students of Universiti Sains Malaysia (USM) were chosen randomly and their maximum mouth opening was measured after being asked to open their mouth sufficiently to accommodate three fingers. Measurement was performed from the edge of the upper incisor to the lower incisor using a caliper divider. The difference of median values between male (47.6 mm) and female (40.8 mm) were significant respectively (p<0.05). Thus the width of mouth opening in Malaysian student population is gender dependent although further study with a larger sample size and with other ethnic groups should be carried out, focusing on age

Utilization of Pre-EDFA in Improving CATV Signals in P2P FTTH; A Malaysian Scenario

This paper describes Malaysia’s recent approach in fiber-to-the-home (FTTH) network through the utilization of pre-erbium doped fiber amplifier (pre-EDFA) in improving Community Antenna Television (CATV) signals in point-to-point (P2P) topology. The optical network unit (ONU) input power and the CATV output quality is observed on a television (TV) unit display each time the EDFA current setting is changed, for before and after a second EDFA is installed between transmitter and ONU (pre-EDFA) for a Malaysian scenario. Before pre-EDFA is installed, the dynamic range is not obtained since the saturation point is not clear, and thus could not be pointed yet. The findings after the pre-EDFA is installed is that, the dynamic range is found to be equals to -17.85 dBm ~ 3.03 dBm for fiber spool used length at 15.225 km. The dynamic range is selected based on the ONU input power when the CATV signal’s output is good and clear. The result shows that pre-EDFA improved the CATV signals displayed for a Malaysian scenario

Implementation of Two Way Free Space Quantum Key Distribution

We report an implementation over free space medium of a two way four states quantum key distribution (QKD) protocol namely the LM05. The fully automated setup demonstrated a secure key generation rate of 3.54 kbits per second and quantum bit error rate (QBER) of 3.34% at mean photon number ({\mu}) = 0.15. The maximum tolerable channel loss for secure key generation considering Photon Number Splitting (PNS) attack, was 5.68 [dB]. The result successfully demonstrated the feasibility of a two way QKD protocol implementation over free space medium.Comment: To appear in the April 2012 issue of Optical Engineering (Vol. 51, No. 04