Design of Inverter Based CMOS Amplifiers in Deep Nanoscale Technologies

In this work, it is proposed a fully differential ring amplifier topology with a deadzone voltage created by a CMOS resistor with a biasing circuit to increase the robustness over PVT variations. The study focuses on analyzing the performance of the ring amplifier over process, temperature, and supply voltage variations, in order to guarantee a viable industrial employment in a 7 nm FinFET CMOS technology node for being used as residue amplifier in ADCs. A ring amplifier is a small modular amplifier, derived from a ring oscillator. It is simple enough that it can quickly be designed using only a few inverters, capacitors, and switches. It can amplify with rail-to-rail output swing, competently charge large capacitive loads using slew-based charging, and scale well in performance according to process trends. In typical process corner, a gain of 72 dB is achieved with a settling time of 150 ps. Throughout the study, the proposed topology is compared with others presented in literature showing better results over corners and presenting a faster response. The proposed topology isn’t yet suitable for industry use, because it presents one corner significantly slower than the rest, namely process corner FF 125 °C, and process corner FS -40 °C with a small oscillation throughout the entire amplification period. Nevertheless, it proved itself to be a promising technique, showing a high gain and a fast settling without oscillation phase, with room for improvement.Neste trabalho, é proposta uma topologia de ring amplifier com a deadzone a ser criada através de uma resistência CMOS com um circuito de polarização para aumentar a robustez para as variações PVT. O estudo foca-se em analisar a performance do ring amplifier nas variações de processo, temperatura e tensão de alimentação, de forma a garantir um uso viável em indústria na tecnologia de 7 nm FinFET CMOS, para ser usado como amplificador de resíduo em ADCs. Um ring amplifier é um pequeno amplificador modular, derivado do ring oscillator. É simples o suficiente para ser facilmente projetado usando apenas poucos inversores, condensadores e interruptores. Consegue amplificar com rail-to-rail output swing, carregar grandes cargas capacitivas com carregamento slew-based e escalar bem em termos de performance de acordo com o processo. No typical process corner, foi obtido um ganho de 72 dB com um tempo de estabilização de 150 ps. Durante o estudo, a topologia proposta é comparada com outras presentes na literatura mostrando melhores resultados over corners e apresentando uma resposta mais rápida. A topologia proposta ainda não está preparada para uso industrial uma vez que apresenta um corner significativamente mais lento que os restantes, nomeadamente, process corner FF 125 °C, e outro process corner, FS -40 °C, com uma pequena oscilação durante todo o período de amplificação. Todavia, provou ser uma técnica promissora, apresentando um ganho elevado e uma rápida estabilização sem fase de oscilação, com espaço para melhoria

Amphibians and reptiles of the Refúgio de Vida Silvestre Mata do Junco, municipality of Capela, state of Sergipe, northeastern Brazil

The Brazilian Atlantic Rainforest has high diversity levels of amphibians and reptiles, but there is a lack of richness survey at several areas, while a high level of deforestation is already known. The biome is highly endangered in northeastern Brazil, and few protected areas have been the main mechanism for providing the habitat conservation. We studied the Refúgio da Vida Silvestre Mata do Junco, a recently established conservation unit in this biome, at the Capela municipality, in the state of Sergipe. Field surveys and literature review were conducted between 2007-2009, revealing 33 species of anuran amphibians and 26 of reptiles (one turtle, ten lizards and 15 snakes). The presence of rare and endemic species suggests an important role of this area as a source remnant of the northeastern Atlantic Forest herpetological community

Urinary estrogen metabolites and self-reported infertility in women infected with Schistosoma haematobium.

BACKGROUND: Schistosomiasis is a neglected tropical disease, endemic in 76 countries, that afflicts more than 240 million people. The impact of schistosomiasis on infertility may be underestimated according to recent literature. Extracts of Schistosoma haematobium include estrogen-like metabolites termed catechol-estrogens that down regulate estrogen receptors alpha and beta in estrogen responsive cells. In addition, schistosome derived catechol-estrogens induce genotoxicity that result in estrogen-DNA adducts. These catechol estrogens and the catechol-estrogen-DNA adducts can be isolated from sera of people infected with S. haematobium. The aim of this study was to study infertility in females infected with S. haematobium and its association with the presence of schistosome-derived catechol-estrogens. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional study was undertaken of female residents of a region in Bengo province, Angola, endemic for schistosomiasis haematobia. Ninety-three women and girls, aged from two (parents interviewed) to 94 years were interviewed on present and previous urinary, urogenital and gynecological symptoms and complaints. Urine was collected from the participants for egg-based parasitological assessment of schistosome infection, and for liquid chromatography diode array detection electron spray ionization mass spectrometry (LC/UV-DAD/ESI-MSn) to investigate estrogen metabolites in the urine. Novel estrogen-like metabolites, potentially of schistosome origin, were detected in the urine of participants who were positive for eggs of S. haematobium, but not detected in urines negative for S. haematobium eggs. The catechol-estrogens/ DNA adducts were significantly associated with schistosomiasis (OR 3.35; 95% CI 2.32-4.84; P≤0.001). In addition, presence of these metabolites was positively associated with infertility (OR 4.33; 95% CI 1.13-16.70; P≤0.05). CONCLUSIONS/SIGNIFICANCE: Estrogen metabolites occur widely in diverse metabolic pathways. In view of the statistically significant association between catechol-estrogens/ DNA adducts and self-reported infertility, we propose that an estrogen-DNA adduct mediated pathway in S. haematobium-induced ovarian hormonal deregulation could be involved. In addition, the catechol-estrogens/ DNA adducts described here represent potential biomarkers for schistosomiasis haematobia

Numbers of positive (E+) and negative (E-) estrogen metabolites in urine samples according to the fertility status of the study participants.

<p>Women unable to become pregnant after one year of trial (Self-reported primary infertility - Group 2) and those who had borne fewer children than desired (Self-reported secondary infertility - Group 3).</p><p>OR, odds ratio; CI, confidence interval.</p

Status of fertility among Angolan women who provides urine samples positive (<i>S. haematobium</i> +ve) and negative (<i>S. haematobium</i> -ve) for eggs of <i>Schistosoma haematobium</i>, according to the age of the participants.

a<p>Women had been unable to become pregnant after one year of trial (self-reported primary infertility, Group 2) and those who had borne fewer children than they desired (self-reported secondary infertility, Group 3).</p

Major metabolic pathways in cancer initiation by estrogens.

<p>Adapted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096774#pone.0096774-Lopes1" target="_blank">[21]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0096774#pone.0096774-Feldmeier1" target="_blank">[22]</a>.</p

Numbers of positive (<i>S. haematobium</i> +ve) and negative (<i>S. haematobium</i> -ve) urine samples for eggs of <i>Schistosoma haematobium</i> according to the age of the participants.

<p>Numbers of positive (<i>S. haematobium</i> +ve) and negative (<i>S. haematobium</i> -ve) urine samples for eggs of <i>Schistosoma haematobium</i> according to the age of the participants.</p

Chemical structures, retention times (RT) and m/z values for the four main components identified by LC–MS analysis of urine of <i>Schistosoma haematobium</i>-infected females.

<p>Atomic mass (m); atomic charge (z).</p

Symptoms and fertility state of 93 female residents of the Bengo region of Angola, an area endemic for schistosomiasis haematobia.

<p>Women unable to become pregnant after one year of trial (self-reported primary infertility - Group 2) and those who had borne fewer children than desired (self-reported secondary infertility - Group 3).</p><p><i>Sh egg</i> +ve, positive for eggs of <i>S. haematobium</i> in urine; <i>Sh egg</i> –ve, negative for eggs of <i>S. haematobium</i> in urine.</p><p>OR, odds ratio; CI, confidence interval.</p