Highly linear micropower class AB current mirrors using Quasi-Floating Gate transistors

A design approach to achieve low-voltage micropower class AB CMOS cascode current mirrors is presented. Both class AB operation and dynamic cascode biasing are based on the use of Quasi-Floating Gate transistors. They allow high linearity for large signal currents and accurately set quiescent currents without requiring extra power consumption or supply voltage requirements. Measurement results show that dynamic cascode biasing allows a wider input range and a linearity improvement of more than 23 dB with respect to the use of conventional biasing. A THD value better than −35 dB is measured for input amplitudes up to 100 times the bias currents. Two class AB current mirror topologies are proposed, with slightly different ways to achieve class AB operation and dynamic biasing. The proposed current mirrors, fabricated in a 0.5 µm CMOS technology, are able to operate with a supply voltage of 1.2 V and a quiescent power consumption of only 36 µW, using a silicon area <0.025 mm².     

Parameterized key assignment for confidential communication in wireless networks

Predistribution of cryptographic keys is a widely used approach for establishing secure communication between severely resource-constrained nodes with limited or no access to network infrastructure. Many proposed key predistribution schemes make the implicit assumption that message contents need not be kept private from nodes other than the intended recipient. Messages in such schemes are not guaranteed to be confidential—they may be read by nodes within the network other than the intended recipient. In this paper, we present TASK—a symmetric key predistribution scheme that enables secure and confidential communication within wireless networks. TASK distributes keys by generating and reinforcing a series of template key assignment instances. It is parameterized, which allows it to make use of key storage capacities that other recently proposed schemes cannot. We show, through analysis and simulation, that TASK can achieve a level of security superior to that of two recently proposed schemes that also provide confidentiality. We also demonstrate that the techniques used in TASK (namely parameterization, templatization, and selective reinforcement) can be applied to other key assignment schemes for star or bipartite networks.     

Compound-specific chlorine isotope analysis: a comparison of gas chromatography/isotope ratio mass spectrometry and gas chromatography/quadrupole mass spectrometry methods in an interlaboratory study

Chlorine isotope analysis of chlorinated hydrocarbons like trichloroethylene (TCE) is of emerging demand because these species are important environmental pollutants. Continuous flow analysis of noncombusted TCE molecules, either by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) or by GC/quadrupole mass spectrometry (GC/qMS), was recently brought forward as innovative analytical solution. Despite early implementations, a benchmark for routine applications has been missing. This study systematically compared the performance of GC/qMS versus GC/IRMS in six laboratories involving eight different instruments (GC/IRMS, Isoprime and Thermo MAT-253; GC/qMS, Agilent 5973N, two Agilent 5975C, two Thermo DSQII, and one Thermo DSQI). Calibrations of (37)Cl/(35)Cl instrument data against the international SMOC scale (Standard Mean Ocean Chloride) deviated between instruments and over time. Therefore, at least two calibration standards are required to obtain true differences between samples. Amount dependency of δ(37)Cl was pronounced for some instruments, but could be eliminated by corrections, or by adjusting amplitudes of standards and samples. Precision decreased in the order GC/IRMS (1σ ≈ 0.1‰), to GC/qMS (1σ ≈ 0.2-0.5‰ for Agilent GC/qMS and 1σ ≈ 0.2-0.9‰ for Thermo GC/qMS). Nonetheless, δ(37)Cl values between laboratories showed good agreement when the same external standards were used. These results lend confidence to the methods and may serve as a benchmark for future applications.     

Chemical dosing for sulfide control in Australia: An industry survey

Controlling sulfide (H₂S) production and emission in sewer systems is critical due to the corrosion and malodour problems that sulfide causes. Chemical dosing is one of the most commonly used measures to mitigate these problems. Many chemicals have been reported to be effective for sulfide control, but the extent of success varies between chemicals and is also dependent on how they are applied. This industry survey aims to summarise the current practice in Australia with the view to assist the water industry to further improve their practices and to identify new research questions. Results showed that dosing is mainly undertaken in pressure mains. Magnesium hydroxide, sodium hydroxide and nitrate are the most commonly used chemicals for sewers with low flows. In comparison, iron salts are preferentially used for sulfide control in large systems. The use of oxygen injection has declined dramatically in the past few years. Chemical dosing is mainly conducted at wet wells and pumping stations, except for oxygen, which is injected into the pipe. The dosing rates are normally linked to the control mechanisms of the chemicals and the dosing locations, with constant or profiled dosing rates usually applied. Finally, key opportunities for improvement are the use of mathematical models for the selection of chemicals and dosing locations, on-line dynamic control of the dosing rates and the development of more cost-effective chemicals for sulfide control.     

Insights behind the Relationship between Colorectal Cancer and Obesity: Is Visceral Adipose Tissue the Missing Link?

Colorectal cancer (CRC) is a major health problem worldwide, with an estimated 1.9 million new cases and 915,880 deaths in 2020 alone. The etiology of CRC is complex and involves both genetic and lifestyle factors. Obesity is a major risk factor for CRC, and the mechanisms underlying this link are still unclear. However, the generalized inflammatory state of adipose tissue in obesity is thought to play a role in the association between CRC risk and development. Visceral adipose tissue (VAT) is a major source of proinflammatory cytokines and other factors that contribute to the characteristic systemic low-grade inflammation associated with obesity. VAT is also closely associated with the tumor microenvironment (TME), and recent evidence suggests that adipocytes within the TME undergo phenotypic changes that contribute to tumor progression. In this review, we aim to summarize the current evidence linking obesity and CRC, with a focus on the role of VAT in tumor etiology and progression.     

Unpredicted Aberrant Splicing Products Identified in Postmortem Sudden Cardiac Death Samples

Molecular screening for pathogenic mutations in sudden cardiac death (SCD)-related genes is common practice for SCD cases. However, test results may lead to uncertainty because of the identification of variants of unknown significance (VUS) occurring in up to 70% of total identified variants due to a lack of experimental studies. Genetic variants affecting potential splice site variants are among the most difficult to interpret. The aim of this study was to examine rare intronic variants identified in the exonic flanking sequence to meet two main objectives: first, to validate that canonical intronic variants produce aberrant splicing; second, to determine whether rare intronic variants predicted as VUS may affect the splicing product. To achieve these objectives, 28 heart samples of cases of SCD carrying rare intronic variants were studied. Samples were analyzed using 85 SCD genes in custom panel sequencing. Our results showed that rare intronic variants affecting the most canonical splice sites displayed in 100% of cases that they would affect the splicing product, possibly causing aberrant isoforms. However, 25% of these cases (1/4) showed normal splicing, contradicting the in silico results. On the contrary, in silico results predicted an effect in 0% of cases, and experimental results showed >20% (3/14) unpredicted aberrant splicing. Thus, deep intron variants are likely predicted to not have an effect, which, based on our results, might be an underestimation of their effect and, therefore, of their pathogenicity classification and family members’ follow-up.     

Automatic cataloguing of advertisement in magazines

Advertising activities are one of the main aspects of companies. Its global evaluation is an important index, not only within economic sectors, but also for public economic policies. The evaluation of the adverts is carried out by specialised companies, which deliver advertisement expenditure information. Their work consist in an exhaustive collection of adverts (e.g., all adverts from any media), and deliver information (integrated from every media) relevant for their clients. The delivered information can range from statistical data to bear witness of an advertisement campaign. Important quality indicators for the delivered information are the exhaustiveness, the delay of delivering and a correct identification of different versions of an advert. In this article, we present an advanced computer-aided system for collecting and delivering advertising information from magazines and daily press. The system provides computer-aided data validation and exploitation resources. Using computerised document image analysis and image database indexing and retrieval, the system is able to locate an advert in a page, extract relevant quality indicators and search the advert (or similar ones) in a database. This tool is configured as an intranet and offers resources for image data acquisition, storage/retrieval and advert quality indicators extraction, however, the key of the system is the underlying idea of incorporating computer-aided visual information management.The EU has funded the system construction within the program: European Take-up of essential Information Society Technologies, Integrated Machine Vision (EUTIST-IMV), task CV-AdControl. .     

Sparse Systems in Fixed Point Form

1) A method is shown for reducing dimension of sparse systems of equations given in fixed point form. Economic models provide examples. 2) A given box to be searched for solutions can be reduced using interval intersections. 3) Interval Newton-like methods using either derivatives or slopes can be applied to the reduced system.