Search

The environmental and economic impact of Co-based catalysts necessitates the use of a more environmentally friendly and less expensive catalyst, such as CuO. A cobalt-free CuO catalyst was developed via a simple low-temperature hydrothermal process. The efficiency of the catalyst was analysed for the dehydrogenation of NaBH 4 as well as NH 3 BH 3. Compared with the commercial particulate CuO, hydrothermally prepared CuO nanoplate (CuO HT) exhibits a good hydrogen evolution rate, the rate of hydrogen evolution for CuO_Commercial and CuO HT was experimentally measured to be 240 ml H 2 /min/g and 470.5 ml H 2 /min/g respectively for 0.2 g catalyst for the dehydrogenation of NaBH 4. At a 10 times lower concentration of NaBH 4 with 0.2 g of CuO HT catalyst, the rate of HER recorded was 1086 ml H 2 /min/g. The high catalytic activity of CuO HT could be related to the surface oxygen vacancies or defects generated due to the participation of high molar concentrations of NaOH during the reaction. The stability of both catalysts was investigated, and the rate of hydrogen evolution reaction after three cycles was determined to be 492 ml H2/min/g for CuO_Commercial and 925.1 ml H2/min/g for CuO HT. Despite the fact that the rate of hydrogen evolution was observed to be increased for the third cycle, the volume of water displaced was decreased when compared to the first cycle, which could be due to the presence of a less active Cu 2 O phase retained after temperature treatment. Similarly, with the best catalyst concentration of CuO HT (0.2 g), the hydrogen evolution rate of NH 3 BH 3 was also measured to be 1175 ml H 2 /min/gm. The result evokes a new insight into the evolution of sustainable and eco-friendly catalysts for a better hydrogen economy. [Display omitted] • CuO catalyst for hydrolytic dehydrogenation of metal/chemical hydrides explored. • Hydrothermally prepared CuO nanoplates exhibit higher rate of H 2 -evolution. • Maximum rate of H 2 -evolution at room temperature from NaBH 4 was 470.5 ml H 2 /min/g. • Maximum rate of H 2 -evolution at room temperature from NH 3 BH 3 was 1175 ml H 2 /min/g. • At high temperature the rate of evolution decreases possibly due to NaBO 2 formation. [ABSTRACT FROM AUTHOR]

The wireless mobile communication is being replaced by wireless personal communication due to the advent of the Internet-of-things (IoT). The IoT applications in the 2.4 GHz band face critical trade-off with respect to signal linearity and battery power. The IoT devices require more power to overcome the nonlinear effects in the channel, resulting in rapid discharge of battery. The wireless industry faces a challenge of providing proper signal processing without draining the battery drastically. In this paper, an ultra-low power RF mixer using complementary pre-distortion (CPD) technique is proposed to overcome the trade-off between linearity and power consumption. The proposed CPD based mixer is designed in UMC 180 nm CMOS process, and the post layout simulations using Cadence SpectreRF tool shows an IIP3 of 26.36 dBm and an IIP2 of 137.1 dBm while consuming only 261.6 µW from a 1-V supply. The proposed CPD method gives the better linearity per mW ratio when compared to other recently proposed mixer circuits. The proposed mixer also provides a gain of 11.45 dB while contributing a very low double-sideband noise figure (DSB-NF) of 8.5 dB. The CPD based mixer has a spurious free dynamic range (SFDR) of 91.57 dB which is 10 dB higher than the recently proposed RF front-end while occupying a core area of 0.33 mm2. [ABSTRACT FROM AUTHOR]

Abstract The rising internet-of-things applications in home automation, smart wearables, healthcare monitoring demand small, area efficient, high-performance and low power radio frequency (RF) blocks for effective short-range communication. This growing market demand is addressed in this paper by proposing a fully CMOS radio frequency front-end (RFE) exploiting bulk effect. Apart from the primary function of frequency translation, proper circuit performance concerning the linearity, conversion gain, and noise figure is required for low-cost densely integrated transceivers operating in the 2.4 GHz ISM band. The proposed RFE at 2.4 GHz is designed and implemented in UMC 180 nm CMOS process technology with two modes of operation. In high gain mode (Mode-I), the post-layout simulation with SpectreRF shows a peak gain of 30.06 dB, IIP2 at 64.52 dBm, IIP3 at −2.74 dBm and a DSB-NF of 7.68 dB while consuming only 9.24 mW from the 1.8 V supply. In the high linear mode (Mode-II), the RFE achieves a higher IIP3 of 10.78 dBm, IIP2 of 91.56 dBm, the conversion gain of 23.5 dB, DSB-NF of 9.46 dB while consuming a low power of 3.6 mW. The fully CMOS circuit occupies a core area of only 0.0021 mm2. The proposed front-end exhibits a spurious free dynamic range (SFDR) of 81.18 dB ensuring the high dynamic operation of the wireless system. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the integration of wind energy conversion system (WECS) with photovoltaic (PV) solar farm (SF) which acts as flexible ac transmission system controller-static synchronous compensator during night time, to regulate the point of common coupling voltage and to rectify faults when SF is not producing any active power. The proposed control will enable increased connections of WECS. MATLAB/Simulink based simulation results are presented for validation of the system. [Copyright &y& Elsevier]

Abstract: Dyes especially azo dyes are used extensively as coloring agents in the manufacturing process of inks, textiles, leathers, food and pharmaceuticals. Liver, bacterial (anaerobic and aerobic) and fungal enzymes metabolized azo dyes immediately and released corresponding amines with carcinogenic character. Thus, the metabolism and release of amine products from azo compounds are of considerable interest. The present study emphases on the qualitative and quantitative analysis of products released from xylidine ponceau 2R by extra cellular protein (ECP) of Streptomyces sp. SS07, in comparison with the chemical reduction. It has been observed that both enzymatic and chemical catalysis release considerable quantities of similar type of amine compounds. The extra cellular fluid protein of 0.7852mg/mg of ECP, on treatment with xylidine ponceau 2R, releases 2,4- xylidine, 2,6-xylidine and 2-methyl 3-amino p-quinone as products at pH 9.2 and at 37°C for a contact period of 24h. The clear band obtained in nondenaturing polyacrylamide gel electrophoresis showed the pure nature of the enzyme used for the reduction of dye xylidine ponceau 2R. Further, HPLC and GC–MS analysis of the reaction products after extracted with chloroform, revealed that about 5–20% increase in the quantity of amine was released by ECP. [Copyright &y& Elsevier]

Release of amine products from azo compounds is of considerable interest, since most of the metabolized amine products have toxic and carcinogenic characters. Moreover, most of the azo dyes are extensively used as coloring agents in inks, textiles, leathers, food and pharmaceutical industries. The present study emphasis on the quantification and comparison of amines released from water soluble dyes by (i) extra cellular protein (ECP) of Streptomyces sp. SS07 and by (ii) chemical methods. It has been observed that both the methods release considerable quantities of similar type of amine products. Release of amine compounds by ECP and chemical reduction in acid and alkaline sweat medium from a leather garment sample was also assessed. ECP (0.7852 mg protein/mg of ECP) releases benzidine and 4-amino biphenyl from Direct Black 38 and Direct Brown 1 as stable products at pH 9.2 and at 37 °C for a contact period of 24 h. On comparison with chemical reduction, it was observed that about 5–20% increase in the release of amine products by ECP was observed. However, more than 60% of amine products were released by chemical method from leather garment samples than direct treatment with ECP. [Copyright &y& Elsevier]

A simple and convenient procedure is reported for the synthesis of benzils and aliphatic 1,2-diketones of cyclic and open chain compounds from corresponding hydrobenzoins and 1,2-diols by refluxing with N-bromosuccinimide in carbon tetrachloride in presence or absence of pyridine. [Copyright &y& Elsevier]

There is an aggressive need for the rapid development of 5G based battery-powered, portable, wearable, wireless applications in the telecommunication industry. The battery-powered devices pose a critical challenge in processing higher data rates while achieving less distortion and low-power consumption. Hence, the problem of power-efficient distortion cancellation needs to be addressed to equip the 5G New Radio (NR) based portable, wearable wireless systems for better performance. This work addresses the problem by proposing a complementary post-distortion harmonic cancellation (CPDHC) technique to improve the linearity of the Mixer used in battery-powered wireless systems. In the proposed CPDHC method, the overall third-order transconductance of the input stage is reduced optimally by the overall third-order transconductance of the auxiliary transistors. This optimal reduction in third-order transconductance retards the growth of third-order harmonics in the circuit, thus improving the linearity performance of the Mixer circuit. From post-layout simulations, the current reuse based Mixer achieves an IIP3 of −6.823 dBm before linearization, and with linearization by CPDHC technique, the IIP3 is improved to 5.05 dBm, resulting in a spurious-free dynamic range (SFDR) of 66.03 dB for 100 MHz channel bandwidth. The CPDHC based Mixer contributes an integrated double-sideband noise figure (DSB-NF) of 12.57 dB and a peak gain of 14.36 dB while consuming 1.25 mW from a 1.2 V supply. [ABSTRACT FROM AUTHOR]

The growing market demand for low-power, high-performance radio frequency blocks for effective short-range communication applications, such as home automation, smart wearables, healthcare monitoring, and automotive sensors, is addressed in this work by proposing an RF down-converter (RFDC) network. This work aims to achieve high linearity, low noise figure and high gain simultaneously by optimally splitting the performance between the three stages of the RFDC. The proposed down-conversion system is designed in UMC 180 nm CMOS process technology and the post-layout simulations on RC parasitic values with Cadence SpectreRF shows an IIP3 of 4.25 dBm and an IIP2 of 93.49 dBm. The RFDC provides a peak conversion gain of 19.4 dB and minimum double-sideband noise figure (DSB-NF) of 16.21 dB while consuming only 7.8 mW of power from a 1.5 V supply. The proposed RFDC occupies a chip area of only 0.27mm2. [ABSTRACT FROM AUTHOR]

• A robust and computationally efficient de-noising technique that combines three stages of cascaded adaptive filters like RLS, NLMS and LMS has been proposed. • The filtered output obtained from the RLS, NLMS and LMS adaptive filters are combined using softmax activation function. • The search range (SR), a band of location points from which the HR is estimated, has been selected dynamically by varying the parameter Δ, which depends on the power value of the accelerometer signals. • The proposed method delivers less error value when evaluated on 22 datasets each performing different activity. Wearable devices, such as smart watch use photoplethysmography (PPG) signals for estimating heart rate (HR). The motion artifacts (MA) contained in these PPG signals lead to an erroneous HR estimation. In this manuscript, a new de-noising algorithm has been proposed that uses the combination of cascaded recursive least square (RLS), normalized least mean square (NLMS) and least mean square (LMS) adaptive filters. The MA reduced PPG signals obtained from these cascaded adaptive filters are combined using the softmax activation function. Fast Fourier transform (FFT) is used to estimate the HR from the MA reduced PPG signals and phase vocoder is used to refine the estimated HR. The performance of the proposed method in the form of mean error, standard deviation of the mean error and mean relative error is analyzed using the 22 datasets given for IEEE Signal processing cup 2015. This resulted in an error of 1.86 beat per minute (BPM) tested on 22 datasets which is less compared to other existing methods. [ABSTRACT FROM AUTHOR]

In this paper, a novel inductorless CG-Folded Cascode balun-low noise amplifier (balun-LNA) for 2.4 GHz biomedical receivers is proposed and integrated to a reactively loaded on-chip loop antenna through capacitive on-chip matching network. On-chip antenna has small feed point resistance at 2.4 GHz, hence LNA can be designed for a lower input resistance than the conventional 50 Ω. The single input balun-LNA has balanced differential outputs such that for lower input impedance, the gain and noise figure (NF) are improved. Folded cascode topology improves voltage swing and linearity. Communication range is computed by designing a power amplifier (PA) and two-turn on-chip antenna at transmitter side. Post-layout simulations of LNA, matching network and PA designed in UMC 180 nm technology are carried out using Cadence Virtuoso. LNA has a simulated gain of 21.3 dB, NF of 1.6 dB and IIP3 −1 dB, matching network has S 11 of –23 dB and PA has an output power 18dBm. On-chip transmit and receive antennas designed in Advanced Design System (ADS) have a gain of −20.6 dBi and −16.7 dBi. Compared to reported LNAs integrated with on-chip antennas below 12 GHz, the proposed design has low power consumption of 2.3 mW, higher FoM, small size of 0.65 mm2 and achieves computed inter-chip communication range of 2.3 m with the designed transmitter. [ABSTRACT FROM AUTHOR]

The article reports on determining the direction of blood flow in the veins of the anterior abdominal wall. It states that it is important to determine the direction of blood flow because it differentiates cirrhosis from vena caval obstruction. It says that the direction of blood flow in patients with dilated abdominal wall veins due to cirrhosis is away from the umbilicus, whereas in vena caval obstruction, the direction is either completely above downward or completely below upward.

Expression of gap junction genes CX32 and Cx43 was studied in different stages of in vivo and cultured ovarian follicles in sheep. In the in vivo grown follicles, CX43 expression in the cumulus cells did not change with development but in the oocytes a significant decrease was noted in the early antral follicles. Although CX32 expression in the cumulus cells appeared to decrease continuously, it was significant only from early antral to antral follicles. However, Cx32 expression in oocytes showed an increasing pattern although the increase from early antral to antral stage was not significant. In the cultured follicles CX43 expression in cumulus cells decreased significantly from preantral to early antral follicles, then increased significantly at the antral stage and decreased again in the large antral follicles. The pattern of CX32 expression was similar except for the significant decrease observed with CX43 expression in the large antral follicles. In the oocytes CX43 expression increased significantly from preantral to early antral stage, and decreased significantly at antral and large antral stages. On the other hand CX32 expression increased significantly from early antral to antral follicle stage and then decreased significantly in the large antral follicles. Subsequent to in vitro maturation for 24 h of COCs from in vivo grown large antral follicles, CX43 expression was supressed both in the cumulus cells and oocytes but CX32 expression was compromised only in the oocytes. In the similarly treated COCs’ from in vitro grown large antral follicles, CX43 expression was stimulated both in the cumulus cells and oocytes but CX32 expression was augmented only in the cumulus cells. It is concluded that (i) the gap junction genes follow a stage specific pattern of expression during ovarian follicular development and (ii) in vitro culture adversely influenced the expression of the gap junction genes. [ABSTRACT FROM AUTHOR]

To test the hypothesis that the poor development of the oocytes in cultured ovarian follicles of mammals is due to aberrant expression of developmentally important genes, quantitative expression patterns of Bcl2 (B-cell leukemia/lymphoma 2; antiapoptotic) and Bax (Bcl2-associated X protein; proapoptotic) genes in preantral, early antral, antral, large antral follicles, and cumulus–oocyte complexes (COCs) grown in vivo or cultured in vitro were studied. The level and pattern of expression of Bcl2 in the cumulus cells isolated from different development stages of in vivo– and in vitro– grown ovarian follicles were similar suggesting that in vitro culture did not alter the expression of this antiapoptotic gene in the cumulus cells. However, between the in vivo– and in vitro– grown ovarian follicles (1) Bcl2 expression levels in the oocytes from antral follicles (2.21 ± 0.14 vs. 0.87 ± 0.19), large antral follicles (0 ± 0.35 vs. 1.56 ± 0.13), and COCs (0.45 ± 0.31 vs. 2.69 ± 0.15), Bax expression levels in the (2) cumulus cells from early antral (2.09 ± 0.11 vs. 0.98 ± 0.13) and large antral follicle (0.63 ± 0.44 vs. 0 ± 0.21), and (3) oocytes from antral follicles (1.65 ± 0.20 vs. 0.97 ± 0.15), large antral follicles (0.93 ± 0.18 vs. 2.08 ± 0.11), and COCs (1.03 ± 0.17 vs. 2.09 ± 0.11) were significantly different (P ≤ 0.05). Similarly, Bcl2 to Bax ratios were also significantly different between some but not all stages of in vivo and in vitro development. From the present results, it is concluded that imbalance in the expression of proapoptotic and antiapoptotic genes may be an important cause for the compromised development potential of the oocytes in cultured ovarian follicles of sheep. [ABSTRACT FROM AUTHOR]

Vanada- and niobatricarbadecaboranyl monohalide complexes proved to be potent cytotoxic agents against murine and human leukemia and lymphoma growth as well as HeLa suspended uterine carcinoma. The vanada complex reduced the growth of KB nasopharynx, Hepe liver, HCT-8 ileum and 1-A9 ovary solid carcinomas. A mode of action study in human HL-60 promyelocytic leukemia cells showed that DNA and purine de novo syntheses were significantly inhibited with suppression of the regulatory enzymes activities of DNA polymerase α and PRPP-amido transferase. There was moderate inhibition of RNA synthesis and m-RNA polymerase activity. These complexes did not inhibit human topoisomerase I or II activity, although the niobium complex nicked the DNA. The complexes did activate caspases 3, 6 and 9 which are linked to apoptosis programmed cell death. These vanada- and niobatricarbadecaboranyl monohalide complexes appear to be more specific in their effects on leukemia cell metabolism than other sandwich complexes which have broad effects on multiple enzymes. [Copyright &y& Elsevier]

With 5G expected to roll out in 2020, the 5 GHz band will be sort after for sub-6 GHz 5G implementation. The feasibility of the wireless systems at 5 GHz will be primarily determined by the linearity of the RF down-converters in the receiver system. With growing battery-powered, portable, and wearable wireless devices, the task of achieving excellent linearity with low power consumption in RF down-converters is difficult. This work tries to overcome the difficulty by proposing a double-linearization (DL) based RF mixer. The proposed mixer circuit is designed using UMC 180 nm CMOS process libraries, and the post-layout simulations are carried out using Cadence SpectreRF in the presence of single-sideband phase noise. For a fundamental tone at 5 GHz and an interferer at 5.01 GHz, the proposed mixer using double-linearization achieves an input-referred third-order intercept point (IIP3) of 11.04 dBm, which is a 15 dB improvement over the IIP3 obtained before employing the proposed scheme. The proposed RF mixer circuit provides a conversion gain of 15.33 dB and an integrated double-sideband noise figure (DSB-NF) of 16.39 dB while consuming a low power of 1.5mW from a 1 V supply. The circuit also boasts an SFDR of 81.36 dB and IMR2 of 192.1 dB. The I I P 3 / m W ratio of the DL based mixer is 6.5 dB more than the recently proposed mixer topology. The layout of the proposed mixer consumes 0.57 m m 2. [ABSTRACT FROM AUTHOR]