Design of Operational Transconductance Amplifier using Double Gate MOSFET

Operational Ttransconductance Amplifier is very popular in analog electronics industry due to its vast applications. Analog integrated circuits have been widely used for high frequency applications. OTA has number of applications like filters, analog multipliers and analog dividers. Double gate MOSFETs (DG-MOSFETs) are strong contenders for nano scale region due its better control over short channel effects. DG-MOSFET can be used in analog circuit applications as a four-terminal device. Back gate bias can be used for better tunability. The double gate based circuits provide additional gains in terms of area, power and speed. This paper presents double gate based OTA which has high gain over a wide bandwidth. The simulation results shows gain of 9.32 dB and bandwidth is 7GHz.The simulations are done using Tanner EDA Software Tool at 90nm technology. Keywords: DG MOSFETs, OTA, Analog tunable circuits, Gain, Wide bandwidth, CMOS Process, Double gates, Self cascode techniqu

Design of Second Order Low Pass and High Pass Filter using Double Gate MOSFET based OTA

OTA-C filters are one of the most widely used as continuous time filters. It is because they are fast active integrators, provides low-power operation and tuning of the filter characteristics at higher frequencies. At high frequencies, the OP AMP based active filters has limited performance. We cannot change the values of resistors and inductors but OTA-C filter provides ability to change their values by changing the transconductance of OTA. Second order low and high pass filter structures have widespread applications. The double gate MOSFETs show better performance in the nanometer range of operation. Because it has better control over short channel effects (SCE’s) and other scaling related problems like gate leakage, sub-threshold conduction. Double gate MOSFET is four terminal device and back gate can be used for biasing which can tune the characteristics of circuit. This will provide additional advantage of low power and reduced area. This paper presents second order low pass and high pass filter based on double gate OTA for VHF and UHF frequency applications. The proposed filter consists of two OTAs and two capacitors. This filter shows low sensitivity to passive components, low component count and ease in design.  The simulation results shows pass band frequency of 14MHz and power consumption of 153.4 µwatt. The simulations are done using Tanner EDA version 13.0 at 90nm technology. Keywords: DG MOSFETs; OTA-C; Analog tunable circuits; Gain; Bandwidth; Double gate; Self cascode technique; Low pass filter; High pass filter

F(T) Models within Bianchi Type I Universe

In this paper, we consider spatially homogenous and anisotropic Bianchi type I universe in the context of F(T) gravity. We construct some corresponding models using conservation equation and equation of state parameter representing different phases of the universe. In particular, we take matter dominated era, radiation dominated era, present dark energy phase and their combinations. It is found that one of the models has a constant solution which may correspond to the cosmological constant. We also derive equation of state parameter by using two well-known F(T) models and discuss cosmic acceleration.Comment: 19 pages, accepted for publication in Mod. Phys. Lett.

Ultrazvučna procjena reakcije jajnika nakon primjene mjera svjetlosnoga režima u deva (Camelus dromedarius).

The present study was carried out with two objectives, (a) the use of ultrasound scanners to study the effect of ‘mask on eyes’ as a photoperiodic control measure for folliculogenesis in female camels, (b) Use of blood progesterone assays to monitor ovarian changes in camels. Fourteen female camels aged 7-11 years were used for the present experiment. Seven were studied for the effect of a mask over the eyes (for six hours daily) as a photoperiodic control measure on ovarian activity and the remaining seven were kept as controls. Ovaries were examined by ultrasound at weekly intervals for seven weeks during the non-breeding season. Camels were mated with virile stud when a follicle (≥0.9 cm diameter, ovulating size) was visible on either of the ovaries. Ovaries were monitored for ovulation up to 48 h post-mating by ultrasound at 12 hourly intervals and at 20, 30 and 40 days post mating to ascertain pregnancy. A commercially available RIA kit was used for serum progesterone assay on samples obtained at 0, 7, 15, 30 and 45 days of mating. No follicle was observed in camels before treatment and in treated (masked) or untreated camels during the first week of treatment. By the third week 100% camels in the treatment group evidenced measurable small follicles (0.5-0.89 cm, 6/7) or follicles of ovulating size (≥0.9 cm, 1/7). Follicles of ovulating size were observed in 28.6, 14.3, 14.3 and 14.3 percent camels by 4th, 5th, 6th and 7th week of treatment. Fifty percent (3/6) of the camels became pregnant. The serum plasma progesterone level increased after ovulation and remained higher than 1.0 ng/mL in pregnant camels. In the control group one camel showed a follicle (0.6 cm diameter) at the 5th week, which did not reach ovulating size. The results of the present study indicate that protecting eyes from sunlight one or two months ahead of the breeding season stimulates follicular growth in camels and pregnancy can occur in these camels when mated.Istraživanje je provedeno u svrhu ultrazvučnoga praćenja utjecaja svjetlosnoga razdoblja kontroliranog pomoću maske na očima na tijek i dinamiku folikulogeneze u deva i određivanja razine progesterona za praćenje cikličnih promjena na jajnicima. Promatrano je 14 deva u dobi od sedam do 11 godina koje su bile podijeljene u pokusnu (n = 7) i kontrolnu skupinu (n = 7). Devama u kontrolnoj skupini svakodnevno je stavljana maska na oči tijekom 6 sati u razdoblju od 7 tjedana izvan rasplodne sezone. Deve su ultrazvučno pregledavane jednom tjedno za vrijeme čitavoga trajanja istraživanja. One su bile parene s plodnim mužjakom kad je uočen folikul na jajniku (≥0,9 cm promjera, ovulacijski folikul). Kad je uočen ovulacijski folikul, jajnici su bili pregledavani ultrazvukom svakih 12 sati u razdoblju od 48 sati radi potvrđivanja ovulacije, a potom nakon 20, 30 i 40 dana radi potvrđivanja gravidnosti. Uzorci krvi bili su uzeti 0., 7., 15., 30. i 45. dana nakon parenja, a plazma je bila analizirana komercijalnim RIA kompletom za određivanje koncentracije progesterona. Prije početka istraživanja i tijekom prvog tjedna istraživanja nijedna deva nije imala folikule na jajnicima. Do trećega tjedna istraživanja, uočeni su folikuli u svih deva pokusne skupine, ali su većinom bili maloga promjera (0,5 - 0,89 cm, 6/7), osim u jedne deve u koje je folikul bio ovulacijske veličine (>0,9 cm). Folikuli koji su po veličini odgovarali ovulacijskim folikulima ustanovljeni su u 28,6% deva tijekom 4. tjedna, 14,3% tijekom 5. tjedna, 14,3% tijekom 6. i 14,3% deva tijekom 7. tjedna istraživanja. Koncipiralo je 50% deva (3/6). Razina progesterona u krvi porasla je nakon ovulacije i bila je veća od 1 ng/ml u svih gravidnih deva. U kontrolnoj skupini samo je jedna deva imala folikul (0,6 cm) na jajniku tijekom 5. tjedna, ali on nije dosegnuo ovulacijsku veličinu. Rezultati istraživanja pokazuju da zaštita očiju od svjetlosti mjesec do dva prije sezone parenja potiče razvoj folikula u deva i može dovesti do gravidnosti ako se deve tada par

Using empirical science education in schools to improve climate change literacy

Providing children with a clear understanding of climate change drivers and their mitigation is crucial for their roles as future earth stewards. To achieve this, it will be necessary to reverse the declining interest in STEM (Science, Technology, Engineering and Mathematics) education in schools in the UK and other countries, as STEM skills will be critical when designing effective mitigation solutions for climate change. The ‘Heat-Cool Initiative’ was co-designed and successfully implemented in five primary/secondary UK schools, as a playful learning tool to unleash student interest in STEM subjects. 103 students from two cohorts (years 5–6 and 7–9) participated in five Heat-Cool activity sessions where they used infrared cameras to explore the issue of urban heat. Their learning was evaluated using a multi-functional quantitative assessment, including pre- and postsession quizzes. Climate change literacy increased by 9.4% in primary school children and by 4.5% in secondary school children. Analyses of >2000 infrared images taken by students, categorised into 13 common themes, revealed age-related differences in children’s cognitive development. At primary school age, images of the ‘self’ dominated; secondary school children engaged more with their physical environment. This novel approach demonstrated the importance of developing tailored technology-enhanced STEM education programmes for different age cohorts, leading to a high capacity for improving learning outcomes regarding climate change. Such programmes, embedded in school curricula nationally and internationally, could become a much-needed positive contribution to reaching the United Nation’s Sustainable Development Goals, especially Goals 4 (Quality Education) and 13 (Climate Action)

Non-vacuum Solutions of Bianchi Type VI_0 Universe in f(R) Gravity

In this paper, we solve the field equations in metric f(R) gravity for Bianchi type VI_0 spacetime and discuss evolution of the expanding universe. We find two types of non-vacuum solutions by taking isotropic and anisotropic fluids as the source of matter and dark energy. The physical behavior of these solutions is analyzed and compared in the future evolution with the help of some physical and geometrical parameters. It is concluded that in the presence of isotropic fluid, the model has singularity at $\tilde{t}=0$ and represents continuously expanding shearing universe currently entering into phantom phase. In anisotropic fluid, the model has no initial singularity and exhibits the uniform accelerating expansion. However, the spacetime does not achieve isotropy as $t\rightarrow\infty$ in both of these solutions.Comment: 20 pages, 5 figures, accepted for publication in Astrophys. Space Sc

Risk Factors for Nipah Virus Encephalitis in Bangladesh1

Patients in Goalando were likely infected by direct contact with fruit bats or their secretions, rather than through contact with an intermediate host

Triphala inhibits both in vitro and in vivo xenograft growth of pancreatic tumor cells by inducing apoptosis

<p>Abstract</p> <p>Background</p> <p>Triphala is commonly used in Ayurvedic medicine to treat variety of diseases; however its mechanism of action remains unexplored. This study elucidates the molecular mechanism of Triphala against human pancreatic cancer in the cellular and in vivo model.</p> <p>Methods</p> <p>Growth-inhibitory effects of Triphala were evaluated in Capan-2, BxPC-3 and HPDE-6 cells by Sulphoradamine-B assay. Apoptosis was determined by cell death assay and western blotting. Triphala was administered orally to nude mice implanted with Capan-2 xenograft. Tumors were analyzed by immunohistochemistry and western blotting.</p> <p>Results</p> <p>Exposure of Capan-2 cells to the aqueous extract of Triphala for 24 h resulted in the significant decrease in the survival of cells in a dose-dependent manner with an IC50 of about 50 μg/ml. Triphala-mediated reduced cell survival correlated with induction of apoptosis, which was associated with reactive oxygen species (ROS) generation. Triphala-induced apoptosis was linked with phosphorylation of p53 at Ser-15 and ERK at Thr-202/Tyr-204 in Capan-2 cells. Above mentioned effects were significantly blocked when the cells were pretreated with an antioxidant N-acetylcysteine (NAC), suggesting the involvement of ROS generation. Pretreatment of cells with pifithrin-α or U0126, specific inhibitors of p53 or MEK-1/2, significantly attenuated Triphala-induced apoptosis. Moreover, NAC or U0126 pretreatment significantly attenuated Triphala-induced p53 transcriptional activity. Similarly, Triphala induced apoptosis in another pancreatic cancer cell line BxPC-3 by activating ERK. On the other hand, Triphala failed to induce apoptosis or activate ERK or p53 in normal human pancreatic ductal epithelial (HPDE-6) cells. Further, oral administration of 50 mg/kg or 100 mg/kg Triphala in PBS, 5 days/week significantly suppressed the growth of Capan-2 pancreatic tumor-xenograft. Reduced tumor-growth in Triphala fed mice was due to increased apoptosis in the tumors cells, which was associated with increased activation of p53 and ERK.</p> <p>Conclusion</p> <p>Our preclinical studies demonstrate that Triphala is effective in inhibiting the growth of human pancreatic cancer cells in both cellular and in vivo model. Our data also suggests that the growth inhibitory effects of Triphala is mediated by the activation of ERK and p53 and shows potential for the treatment and/or prevention of human pancreatic cancer.</p