An active inductor employing a new four terminal floating nullor transconductance amplifier (FTFNTA)

ABSTRACT

In this scientific study, a new analog active building block named as four terminal floating nullor transconductance amplifier (FTFNTA) is implemented. The FTFNTA design offers a combined essence of both traditional four terminal floating nullor (FTFN) and an operational transconductance amplifier (OTA). The FTFNTA design is extended for the design of a lossless floating and grounded inductor simulator with few passive components. In addition, the performance and usefulness of the proposed inductor topology are also expanded for active filter applications: higher-order Butterworth high-pass filter and current mode multifunction filter. The functionality of the CMOS-based FTFNTA is integrated with a 0.18 µm Taiwan Semiconductor Manufacturing Company (TSMC) CMOS technology. Moreover, the FTFNTA is also realised using the current feedback operational amplifier (CFOA/AD844) and OTA (OTA/CA3080) of a commercially available IC to test the viability of the proposed inductor design. Finally, an application based on the inductor topology and its impedance characteristics are well analysed via PSPICE simulation.     

Complexation of N＇- [1-（3-aminophenyl）ethylidine] isonicotinohydrazide with La3＋, Pr3＋, Nd3＋, Sm3＋, Eu3＋ and Gd3＋ ions and associated thermodynamics

A novel Schiff base N′-[1-(3-aminophenyl)ethylidine]isonicotinohydrazide was prepared and its complexation behavior towards some selected lanthanides had been studied employing pH-metric and calorimetric titration and spectral techniques. pH-metric studies were carried out for the trivalent La, Pr, Nd, Sm, Eu, and Gd complexes in 30% aqueous-dioxane medium at constant ionic strength of 0.05 mol/L NaClO4 and at different temperatures of 293, 303 and 313 K. The proton-ligand formation constants of the ligand indicated the presence of only one dissociable proton while the metal-ligand formation constants were compatible with the formation of 1:1 Ln(Ⅲ) complexes. The sta-bility of the complexes followed the order: La3+Gd3+, showing a break at gadolinium. The thermodynamic parame-ters, ΔG, ΔH and ΔS associated with protonation and complexation reactions were negative which suggested that all reactions were exother-mic and enthalpy-driven. Isothermal calorimetric studies of Gd3+-aeINH systems at 303 K also showed exothermic nature of the complexation reaction and formation of 1:1 complex in agreement with the pH-metric data. Formation of 1:1 complexes was confirmed by the characteriza-tion of Nd(Ⅲ) complex. A seven coordinated geometry was assigned for the complex based on its elemental and spectral data.     

Simplet and its Application in Signal Encryption

We propose here a transform which is a new kind of multi-level subband signal decomposition and reconstruction scheme. It is called Simplet which stands for Simple transform and is simple, easy to understand and perfectly reconstructible. No decomposition or reconstruction filter is explicitly required in Simplet. Another advantage of this transform is that the length of the decomposed components in each level of decomposition is equal to the length of the input signal. Computationally, Simplet can be made a constant time transform. There are various forms of Simplet that can be used in various applications of signal and image processing. Simplet is of two types. One is useful for multiresolution signal analysis and the other for signal distortion. We use the later type here for an encryption scheme. In the existing transforms, even when there is noise in the decomposed components, the reconstructed signal is perceptually intelligible. However, in Simplet the reconstructed signal is perceptually unintelligible when the decomposed components have noise in them. This property is made use of in our encryption scheme which first uses Simplet to protect the distinguishable features of the signal by decomposing it into two or more distorted components and then encrypts them by using a special sequence of numbers. This sequence is called Meitei Lock Sequence (MLS) and is generated from a non-zero key vector of an arbitrary length. An MLS is unique for a key vector. Once a signal is encrypted with an MLS, it can be decrypted only with that particular MLS. As an MLS is generated from an arbitrary vector, the search space for finding a particular MLS is very large and hence gives very tight security in our encryption scheme. We have found that the empirical correlation coefficient between an original signal and a decrypted signal using any decryption key that is different from (even if very close to) the actual key, is sufficiently small. The encryption scheme is fast as both the Simplet and MLS are fast algorithms.     

Poncirin Induces Apoptosis in AGS Human Gastric Cancer Cells through Extrinsic Apoptotic Pathway by up-Regulation of Fas Ligand

Poncirin, a natural bitter flavanone glycoside abundantly present in many species of citrus fruits, has various biological benefits such as anti-oxidant, anti-microbial, anti-inflammatory and anti-cancer activities. The anti-cancer mechanism of Poncirin remains elusive to date. In this study, we investigated the anti-cancer effects of Poncirin in AGS human gastric cancer cells (gastric adenocarcinoma). The results revealed that Poncirin could inhibit the proliferation of AGS cells in a dose-dependent manner. It was observed Poncirin induced accumulation of sub-G1 DNA content, apoptotic cell population, apoptotic bodies, chromatin condensation, and DNA fragmentation in a dose-dependent manner in AGS cells. The expression of Fas Ligand (FasL) protein was up-regulated dose dependently in Poncirin-treated AGS cells Moreover, Poncirin in AGS cells induced activation of Caspase-8 and -3, and subsequent cleavage of poly(ADP-ribose) polymerase (PARP). Inhibitor studies’ results confirm that the induction of caspase-dependent apoptotic cell death in Poncirin-treated AGS cells was led by the Fas death receptor. Interestingly, Poncirin did not show any effect on mitochondrial membrane potential (ΔΨm), pro-apoptotic proteins (Bax and Bak) and anti-apoptotic protein (Bcl-xL) in AGS-treated cells followed by no activation in the mitochondrial apoptotic protein caspase-9. This result suggests that the mitochondrial-mediated pathway is not involved in Poncirin-induced cell death in gastric cancer. These findings suggest that Poncirin has a potential anti-cancer effect via extrinsic pathway-mediated apoptosis, possibly making it a strong therapeutic agent for human gastric cancer.