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Bio-impedance Spectroscopy (BIS) is a technique that allows tissue analysis to diagnose a variety of diseases, such as medical imaging, cancer diagnosis, muscle fatigue detection, glucose measurement, and others under research. The development of CMOS integrated circuit front-ends for bioimpedance analysis is required by the increasing use of wearable devices in the healthcare field, as they offer key features for battery-powered wearable devices. These features include high miniaturization, low power consumption, and low voltage power supply. A key circuit in BIS systems is the current source, and one of the most common topology is the Enhanced Howland Current Source (EHCS). EHCS is also used when the current driver is driven by a pseudo-random signal like discrete interval binary sequences (DIBS), which, due to its broadband nature, requires high performance operational amplifiers. These facts lead to the need for a current source more compatible with DIBS signals, ultra-low power supply, standard CMOS integrated circuit, output current amplitude independent of input voltage amplitude, high output impedance, high load capability, high output voltage swing, and the possibility of tetra-polar BIS analysis, that is a pseudotetra-polar in the case of EHCS. The objective of this work is to evaluate the performance of the Switching CMOS Current Source (SCMOSCS) over EHCS using a Cole-skin model as a load using SPICE simulations (DC and AC sweeps and transient analysis). The SCMOSCS demonstrated an output impedance of more than 20 MΩ, a ± 2.5 V output voltage swing from a +3.3 V supply, a 275 μA current consumption, and a 10 kΩ load capacity. These results contrast with the + 1.5 V output voltage swing, the 3 kΩ load capacity, and the 4.9 mA current of the EHCS case.

This work aims to verify the effects of the natural structure of a residual soil on its erodibility and the potential, employing compaction, to restore the erosion resistance. It is a residual soil of gneiss that occurs in the state of Santa Catarina, Southern Brazil. Infrastructure earthworks expose this material to the action of water, which can develop severe erosive features. The erodibility evaluation was made using the MCT methodology based on infiltrability and modified loss of mass by immersion tests. These tests were conducted in undisturbed specimens at natural moisture content and in compacted specimens at optimum moisture content. Such tests were also carried out in specimens air-dried for 24, 48, and 96 hours. This soil is inherently erosive, but the natural macrostructure makes it even more susceptible to erosion. Even compaction under modified energy is not able to recover the erodibility resistance. Drying slightly reduces the soil’s erosive potential when compacted, regardless of the compaction energy, but clearly increases the erosive potential of undisturbed soil.

Hermetia illucens (Black Soldier Fly) larvae (BSFL) have great potential as new protein source for either feed or food use due to the high content of protein and fat. BSFL may be used in different forms including dried with extended shelf life. Mathematical models describing dehydration kinetics are useful to optimize BSFL drying conditions. A non-stationary 3D diffusion model, given by Fick's Law was used to describe the moisture depletion inside BSFL during drying. The numerical solution of PDE was obtained with COMSOL Multiphysics assuming simple boundary conditions. Data were obtained in a drying experiment performed with fresh larvae uniformly laid on a metallic grid in a forced air oven at 80 °C. Five randomly larvae were periodically selected and removed for moisture content determination until equilibrium moisture was reached. A qualitative good agreement between predictions and data was observed corroborating that the main physical phenomena were considered in the mathematical description. A better quantitave description is expected with the improvement of the boundary condition at larvae surface in the model and the upgrading of the three-dimensional geometry used as domain for the numerical resolution.

Background: Forty-four strains isolated from a cohort of cutaneous leishmaniasis (CL) patients who did or did not respond to one course of treatment with meglumine antimoniate were investigated to explore genetic polymorphisms in parasite kinetoplast DNA minicircles. Leishmania (Viannia) braziliensis strains isolated from responder (R) and non-responder (NR) patients who acquired infection in Rio de Janeiro or in other Brazilian states were studied using low-stringency single-specific primer polymerase chain reaction (LSSP-PCR) to identify genetic polymorphisms. Results: Polymorphisms were observed in parasites recovered from patient lesions. No association was found between a specific genotype and R or NR patients. Phenetic analysis grouped the genotypes into three main clusters, with similarity indices varying from 0.72 to 1.00. Although no specific genotype association was detected, at least one group of L. (V.) braziliensis genotypes that circulates in Rio de Janeiro was discriminated in clusters I and III, showing phenotypes of good and poor responses to treatment, respectively. Cluster I comprised parasite profiles recovered from R patients from Rio de Janeiro and in cluster III, NR samples were prevalent. Cluster II comprised 24 isolates, with 21 from Rio de Janeiro and three from other states, equally distributed between R and NR patients. Additionally, we found that parasites sharing all common genetic characteristics acted differently in response to treatment. Conclusions: These results are of clinical-epidemiological importance since they demonstrate that populations of L. (V.) braziliensis that exhibit high levels of genetic similarity also display different phenotypes associated with meglumine antimoniate responses in cutaneous leishmaniasis patients.