This study describes the development of low cost colorimetric and electrochemical sensors aiming clinical and forensic applications. Firstly, a microfluidic paper-based analytical device (μPAD) was developed as colorimetric sensor for rapid estimation of post-mortem interval (PMI) on the crime scene using human vitreous-humour (VH) samples. Experimental parameters were optimized and the best conditions were: paper 1 CHR, 5 mm microzone diameter, 4 μL sample volume and 0.05 mol/L chromogen concentration. μPADs were coupled to colorimetric detection and the feasibility was demonstrated by Fe2+ determination in VH samples, in which the data were not statistically different from conventional technique (ICP-MS). It is important to highlight that Fe2+ levels were proportional to PMI. A color scale was also developed to help the forensic teams in order to estimate the PMI with a simple, quick and visual way. For electrochemical sensors, two different sensors were proposed to determine salivary α-amylase (sAA) levels in human saliva samples, aiming help in the diagnostic of pancreatitis and periodontitis. The first sensor based in a carbon screen-printed electrode (SPE) associated to amperometric detection. Experimental parameters were optimized and the best conditions were: 5 mmol L-1 NaOH (pH= 12), 20 min reaction time, 15 μL sAA volume and 0.5% (w/v) starch concentration. The feasibility of the sensor was demonstrated by sAA determination in five saliva samples (two from male donators and three from female individuals). The sAA concentrations ranged between 182.1 e 1117.1 U mL-1; once two female samples presented high sAA levels because the use of oral contraceptive. The other proposed electrochemical sensor was based in a Batch Injection Analysis with Amperometric Detection (BIA-AD) system using copper oxide (CuO) as working electrode (WE). Through experimental optimization was selected the potential that generate the best current signal. The WE obtained by a chemical/thermal treatment present good stability, once the relative standard deviation (RSD) value was 0.3%, which is ca. 75 fold lower than the RSD obtained with the electrochemical procedure to generate CuO in the electrode surface. The feasibility of the sensor was demonstrated by sAA determination in four human saliva samples. Was possible distinguish patients with and without periodontitis, obtaining thus a quick information about periodontal state of the patients. In general, the three proposed sensors in this study offered good precision, accuracy and specificity. Furthermore, the sensors are simple, portables, low cost and not requires none sophisticate instrumentation. Therefore, they present as promising alternatives to be used in point-of-care clinical and forensic analysis.

This paper discusses the challenges of 'miniaturizing' the world in Portuguese cartography at the dawn of the Modern Age. It draws attention to the process of amassing experience and geographic knowledge, and their deployment in the cartographic representations of Brazil throughout the first three centuries of its colonization.

Purpose: To compare balloon occlusion prostatic artery embolization (bPAE) with conventional microcatheter PAE (cPAE). Materials and methods: In this single-center trial, between November 2017 and November 2018, 89 patients with symptomatic benign prostatic hyperplasia were randomly assigned to cPAE (n = 43) or bPAE (n = 46). All patients received embolization with 300-500 μm Embosphere microspheres and were evaluated before and 1 and 6 months after PAE. Primary outcome measure was change from baseline in International Prostate Symptom Score (IPSS). Student t test was used for between-group comparisons of change from baseline, and paired t test was used for within-group comparisons. Results: At baseline, groups were identical (P > .05). Unilateral PAE was performed in 4 patients receiving cPAE and 3 patients receiving bPAE (9.30% and 6.52%, P = .708). Procedural and fluoroscopy times, dose area product, air kerma, embolic volume, and mean prostate-specific antigen (PSA) 24 hours after PAE did not differ between groups (P > .05). Coils were used in 6 patients receiving cPAE and 4 patients receiving bPAE (14.0% and 8.70%, P = .51). Assessments at 6 months after PAE showed mean IPSS reduction was 7.58 ± 6.88 after cPAE and 8.30 ± 8.12 after bPAE (P = .65); mean prostate volume reduction was 21.9 cm3 ± 51.6 (18.2%) after cPAE and 6.15 cm3 ± 14.6 (7.3%) after bPAE (P = .05); mean PSA reduction was 0.9 ng/mL ± 2.22 after cPAE and 0.22 ng/mL ± 1.65 after bPAE (P = .10). Penile skin lesions (n = 3) and rectal bleeding (n = 2) were documented only in patients receiving cPAE (11.9%, P = .01). No major adverse events occurred. Conclusions: bPAE is as effective as cPAE in treating benign prostatic hyperplasia with a potential to reduce nontarget embolization.

The miniaturization and improvement of sample preparation is a challenge that has been fulfilled up to a point in many fields of analytical chemistry. Particularly, the hyphenation of microextraction with advanced analytical techniques has allowed the monitoring of target analytes in a vast variety of environmental samples. Several benefits can be obtained when miniaturized techniques such as solid-phase microextraction (SPME) or liquid-phase microextraction (LPME) are applied, specifically, their easiness, rapidity and capability to separate and pre-concentrate target analytes with a negligible consumption of organic solvents. In spite of the great acceptance that these green sample preparation techniques have in environmental research, their full implementation has not been achieved or even attempted in some relevant environmental matrices. In this work, a critical review of the applications of LPME and SPME techniques to isolate and pre-concentrate traces of organic pollutants is provided. In addition, the influence of the environmental matrix on the effectiveness of LPME and SPME for isolating the target organic pollutants is addressed. Finally, unsolved issues that may hinder the application of these techniques for the extraction of dissolved organic matter from environmental samples and some suggestions for developing novel and less selective enrichment and isolation procedures for natural organic matter on the basis of SPME and LPME are included.

[Excerpt] Introduction Miniaturization has played a pivotal role in driving innovation in microfluidic devices, particularly in their application across advanced technologies, such as Lab-on-chip platforms, Point-of-care systems, Organ-, Body- and Disease-on-a-chip technology. The personalized nature inherent in these systems, coupled with physiologically relevant readouts, opens novel avenues for individualized disease diagnostics, Figure 1. Additionally, they offer personalized strategies for assessing treatment efficacy and safety. Furthermore, the advancement in micro- and nano-microfluidic fabrication allows parallel analysis of large samples sets and the evaluation of different parameters such as biological molecules, cells or drugs.[...]

The design, construction and evaluation of a low-cost cyclic olefin copolymer (COC)-based continuous flow microanalyzer with optical detection to determine the titratable acidity content of wine is here presented. The analysis method is based on the monitoring of the blue coloration decrease of a buffered bromothymol blue (BTB) solution in the presence of the acidic compounds of wine. The microanalyzer monolithically integrates the required microfluidic motifs as well as an optical flow cell where the measurements are performed by using a miniaturized and versatile photometric detection system. Fluid management is totally automated by the use of computer-controlled microvalves, permitting the automatic calibration of the system as well as the automatic sampling, including in-line dilution and analysis. The reduced size of the whole system along with its high simplicity and automation make it suitable for its application to the on-line monitoring of titratable acidity during wine-making processes. With the optimal conditions, a linear range up to 0.50 g L−1 tartaric acid, a quantification limit (LOQ) of 0.01 g L−1 and a detection limit (LOD) of 0.004 g L−1 were obtained, covering the most common acidity content of musts and wines. A sampling rate up to 26 h−1 could be achieved, consuming less than 3 mL of inexpensive reagents per analysis and requiring no pretreatment of the sample. The microsystem has been successfully applied to the quantification of the titratable acidity content of several wine samples, being the results in excellent agreement with the ones obtained by the reference method.

One of the major challenges in a chemistry laboratory is the continuous search for a more sustainable practice, following Green Chemistry guidelines. The present work was devoted to the development of a high throughput and miniaturized strategy for chemistry conventional protocols for the study of complex formation of metallic compounds. In this scenario, the spectrophotometric calibration curve method and the Job’s method of continuous variation were adapted to the microplate format. This work involved several metal ions (Co(II), Cu (II), Cd(II), Fe(III), Mn(II), Ni(II), Pb(II) and Zn(II)) and two different complexing agents, 2-Carboxy-2′-hydroxy- 5′-sulfoformazyl-benzene (Zincon) and 4-(2-Pyridylazo)resorcinol (PAR). Microplate assays demonstrated to be useful tools for the investigation of the equilibrium process of metal ion complexes. Additionally, these methods involved lower volume of reagents and the analysis throughput was augmented when compared with conventional strategies

Abstract This paper presents the implementation of a 3-bit microstrip fractal-based phase shifter operating in the 430 MHz to 470 MHz frequency range. The fractal structure is used to confine different delay line lengths in the same area due to the space-filling properties of the used Hilbert fractal curve. The proposed design has three bits corresponding to 45, 90, and 180 degrees phase changes selected according to the switching circuit based on a Double Pole Double Throw (DPDT) switch implemented with PIN diodes. Comparisons between simulated and measured results are shown according to the chosen degree of use of PIN diodes.