Diagnosing applications' I/O behavior through system call observability

We present DIO, a generic tool for observing inefficient and erroneous I/O interactions between applications and in-kernel storage systems that lead to performance, dependability, and correctness issues. DIO facilitates the analysis and enables near real-time visualization of complex I/O patterns for data-intensive applications generating millions of storage requests. This is achieved by non-intrusively intercepting system calls, enriching collected data with relevant context, and providing timely analysis and visualization for traced events. We demonstrate its usefulness by analyzing two production-level applications. Results show that DIO enables diagnosing resource contention in multi-threaded I/O that leads to high tail latency and erroneous file accesses that cause data loss

Micro/nano devices for blood analysis

[Excerpt] The development of microdevices for blood analysis is an interdisciplinary subject that demandsan integration of several research fields such as biotechnology, medicine, chemistry, informatics, optics,electronics, mechanics, and micro/nanotechnologies.Over the last few decades, there has been a notably fast development in the miniaturization ofmechanical microdevices, later known as microelectromechanical systems (MEMS), which combineelectrical and mechanical components at a microscale level. The integration of microflow and opticalcomponents in MEMS microdevices, as well as the development of micropumps and microvalves,have promoted the interest of several research fields dealing with fluid flow and transport phenomenahappening at microscale devices. [...

Preliminary evaluation of a microfluidic device for blood separation and deformation assessment

This work was supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01- 0145-FEDER- 006941. V. Faustino and S.O. Catarino thank, respectively, the FCT for the grants SFRH/BD/99696/2014 and SFRH/BPD/108889/2015, supported by national funds from Ministérios da Ciência, Tecnologia e Ensino Superior and by FSE through the POCH - Programa Operacional Capital Humano

A Passive Microfluidic Device Based on Crossflow Filtration for Cell Separation Measurements: A Spectrophotometric Characterization

Microfluidic devices have been widely used as a valuable research tool for diagnostic applications. Particularly, they have been related to the successful detection of different diseases and conditions by assessing the mechanical properties of red blood cells (RBCs). Detecting deformability changes in the cells and being able to separate those cells may be a key factor in assuring the success of detection of some blood diseases with diagnostic devices. To detect and separate the chemically modified RBCs (mimicking disease-infected RBCs) from healthy RBCs, the present work proposes a microfluidic device comprising a sequence of pillars with different gaps and nine different outlets used to evaluate the efficiency of the device by measuring the optical absorption of the collected samples. This latter measurement technique was tested to distinguish between healthy RBCs and RBCs chemically modified with glutaraldehyde. The present study indicates that it was possible to detect a slight differences between the samples using an optical absorption spectrophotometric setup. Hence, the proposed microfluidic device has the potential to perform in one single step a partial passive separation of RBCs based on their deformability.Research supported by FCT with the reference projects POCI-01-0145-FEDER-016861 (PTDC/QEQ-FTT/4287/2014), NORTE-01-0145-FEDER-029394 (PTDC/EMD-EMD/29394/2017), NORTE-01-0145-FEDER-030171 (PTDC/EME-SIS/30171/2017), UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020, NORTE2020, PORTUGAL2020-Programa Operacional Competitividade e Internacionalizacao (POCI) with the reference project POCI-01-0145-FEDER-006941 and by the NORTE-01-0145-FEDER-028178 (PTDC/EEI-EEE/28178/2017) project, funded 85% from Programa Operacional Regional do Norte and 15% from FCT.info:eu-repo/semantics/publishedVersio

ANALYTICAL METHOD BY HPLC-DAD ALLOWS QUANTIFICATION OF QUERCETIN MARKER IN STANDARDIZED EXTRACT OF ANADENANTHERA COLUBRINA VAR. CEBIL

Objective: The Anadenanthera colubrina (Vell.) Brennan var. cebil is a medicinal plant that has been used for the treatment of many diseases in the northeastern region of Brazil. This plant contains secondary metabolites such as quercetin, a flavonoid that is known by its antioxidant and anti-inflammatory effects. The aim of this work is to propose the validation of an analytical method using high-performance liquid chromatography with diode array detector (HPLC-DAD) for the quantification of quercetin and standardization of the hydroalcoholic extract (HAE) of A. colubrina.Methods: The A. colubrina extracts were prepared by the maceration process with powdered leaves at 20% weight: volume (w/v) and a hydroalcoholic solution at 50% volume: volume (v/v) for 120 h at room temperature. After pretreatment of the hydroalcoholic extract, the quercetin marker was used for quantification and proceeded to the evaluation of validation parameters for the method using HPLC-DAD.Results: The analytical method proved to be specific. Linear over the range 1.4–26.6 µg/ml, regression analysis showed a good correlation coefficient (R2= 0.999); the limit of detection (LOD) and the limit of quantification (LOQ) were 0.27 and 0.81 μg/ml respectively. The relative standard deviation (RSD) did not exceed 2.5% for precision. The proposed method was validated with an average recovery of 92.5–97.5%.Conclusion: The method was validated using HPLC-DAD, allowing the quantification of quercetin in the standardisation process of extracts and quality control of the herbal drug containing A. colubrina Phyto complex

Label-free multi-step microfluidic device for mechanical characterization of blood cells: diabetes type II

The increasing interest to establish significant correlations between blood cell mechanical measurements and blood diseases, has led to the promotion of microfluidic devices as attractive clinical tools for potential use in diagnosis. A multi-step microfluidic device able to separate red and white blood cells (RBCs and WBCs) from plasma and simultaneously measure blood cells deformability (5 and 20% of hematocrit) is presented in this paper. The device employs passive separation based on the cross-flow filtration principle, introduced at each daughter channel. At the outlets, hyperbolic geometries allow single-cell deformability analysis. The device was tested with blood from five healthy and fifteen diabetic type II voluntary donors. The results have shown that WBCs have lower deformability than RBCs, and no significant differences were observed in WBCs from healthy and pathological blood samples. In contrast, RBCs have shown significant differences, with pathological cells exhibiting lower deformability. Shear rheology has shown that blood from patients with type II diabetes has higher viscosity than blood from healthy donors. This microfluidic device has demonstrated the ability to reduce cell concentration at the outlets down to 1%, an ideal cell concentration for assessing the blood cells deformability, under healthy and pathological conditions. The results provide new insights and quantitative information about the hemodynamics of in vitro type II diabetes mellitus RBCs. Thus, such device can be a promising complement in clinical diagnosis and biological research as part of an integrated blood-on-a-chip system.This work was supported by Projects NORTE-01-0145-FEDER-028178, NORTE-01-0145-FEDER-029394, NORTE-01-0145-FEDER-030171 funded by COMPETE2020, NORTE2020, PORTUGAL2020, and FEDER. This work was also supported by Fundacao para a Ciencia e a Tecnologia (FCT) under the strategic grants UIDB/04077/2020 and UIDB/00532/2020. D. Pinho and V. Faustino acknowledge the Ph.D. scholarships SFRH/BD/89077/2012 and SFRH/BD/99696/2014, respectively, both provided by FCT. Susana Catarino thanks FCT for her contract funding provided through 2020.00215.CEECIND. F. T. Pinho is thankful to FCT for financial support through projects LA/P/0045/2020 of the Associate Laboratory in Chemical Engineering (ALiCE) and pro-jects UIDB/00532/2020 and UIDP/00532/2020 of Centro de Estudos de Fenomenos de Transporte

Assessment of the stresses produced on the bone implant/tissue interface to the different insertion angulations of the implant - a three-dimensional analysis by the finite elements method

The present study aimed to assess the stresses produced on the surface of the bone tissue around dental implants with three different insertion angulations subjected to axial and oblique loading. The study was created according to the recommendations of the Checklist for Reporting In-vitro Studies (CRIS). The Straumann? bone level RC (4.1 x 10 mm) implant, Cone Morse connection (CM), RC Straumann Variobase? with abutment (3.5 mm) was placed in the region of element 16, with the platform positioned at the height of the bone crest. Three assessment models were produced: model M1 or control - implant perpendicular to the bone crest; model M2 - implant angulated at 17° relative to the bone crest; and model M3 - implant angulated at 30° relative to the bone crest. The masticatory loads were simulated with 100 N of intensity and two loading patterns (axial and oblique) were applied to each model. Then, the models were exported to the finite elements simulation software Ansys Workbench V19.2 (Ansys Inc., Canonsburg, PA, USA). To assess the finite elements, qualitative and quantitative analyses were performed. It was observed that, under axial loading, qualitatively, the peaks occurred in the cavosurface region, palatal aspect in M1 and M2, and buccal aspect in M3. Quantitatively, the greatest angulation resulted in a low stress peak. Under oblique loading, qualitatively, the peaks occurred in the cavosurface region, buccal aspect in the three groups. Quantitatively, the greatest angulation of the implant resulted in an increase in stress peaks on the buccal aspect. Under axial loading, the three insertion angulations of the implant - M1, M2, and M3 - were clinically viable. When subjected to oblique loading, the 30° angulation (M3) suggested a significant risk of bone loss and it was contraindicated

Social environment affects testosterone level in captive male blue–black grassquits

The challenge hypothesis proposes that testosterone (T) elevation above what is needed for breeding is associated with social factors, and males possibly modulate their hormonal response to variations in population density and sex ratio. We investigated the role of social environment in altering testosterone levels and aggression in a tropical, seasonally breeding grassquit (Volatinia jacarina). We exposed males to three social conditions during 1 year: all-males treatment (six males), mixed treatment (three males–three females), and paired treatment (one male–one female). We quantified aggressiveness among males and T plasma concentration for each individual in each treatment monthly. We found that more aggressive interactions occurred in the all-males treatment than in the mixed treatment. The data also revealed that, coincident with these behavioral changes, the patterns of T variation through time in each treatment were markedly different. The all-males treatment exhibited an early increase in T concentration, which was sustained for a lengthy period with two distinctive peaks, and subsequently declined sharply. The mixed treatment presented an intermediate pattern, with more gradual increase and decrease in T levels. At the other extreme, the paired treatment presented a later rise in T concentration. We conclude that the more competitive environment, with higher density of males, caused the early and higher elevation in T level, thus the presence of competitors may influence the decision of how much a male should invest in reproduction. We suggest that the male's perception of his social environment ultimately mediates hormonal production and alters his reproductive strategy

Microfluidic deformability study of an innovative blood analogue fluid based on giant unilamellar vesicles

Blood analogues have long been a topic of interest in biofluid mechanics due to the safety and ethical issues involved in the collection and handling of blood samples. Although the current blood analogue fluids can adequately mimic the rheological properties of blood from a macroscopic point of view, at the microscopic level blood analogues need further development and improvement. In this work, an innovative blood analogue containing giant unilamellar vesicles (GUVs) was developed to mimic the flow behavior of red blood cells (RBCs). A natural lipid mixture, soybean lecithin, was used for the GUVs preparation, and three different lipid concentrations were tested (1 × 10−3 M, 2 × 10−3 M and 4 × 10−3 M). GUV solutions were prepared by thin film hydration with a buffer, followed by extrusion. It was found that GUVs present diameters between 5 and 7 µm which are close to the size of human RBCs. Experimental flow studies of three different GUV solutions were performed in a hyperbolic-shaped microchannel in order to measure the GUVs deformability when subjected to a homogeneous extensional flow. The result of the deformation index (DI) of the GUVs was about 0.5, which is in good agreement with the human RBC’s DI. Hence, the GUVs developed in this study are a promising way to mimic the mechanical properties of the RBCs and to further develop particulate blood analogues with flow properties closer to those of real blood.COMPETE2020, NORTE2020, PORTUGAL2020, FEDER; FCT Project PTDC/QEQ-FTT/4287/2014 (POCI-01-0145-FEDER-016861); FCT Project PTDC/EMD-EMD/29394/2017 (NORTE-01-0145-FEDER-029394); FCT Project PTDC/EME-SIS/30171/2017 (NORTE-01-0145-FEDER-000032); FCT Project PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020); SFRH/BD/99696/2014 PhD Grant;info:eu-repo/semantics/publishedVersio