Recent developments on the thermal properties, stability and applications of nanofluids in machining, solar energy and biomedicine

In this review work, the recent progress made in the use of nanofluids (NFs) applied in three specific areas will be presented: machining, solar energy, and biomedical engineering. Within this context, the discussions will be guided by emphasizing the thermal and stability properties of these fluids. In machining, NFs play a prominent role in the processes of turning, milling, drilling, and grinding, being responsible for their optimization as well as improving the useful life of the tools and reducing costs. In the solar energy field, NFs have been used in the thermal management of the panels, controlling and homogenizing the operating temperature of these systems. In the biomedical area, the advantages of using NFs come from the treatment of cancer cells, the development of vaccines before the improvement of diagnostic imaging, and many others. In all lines of research mentioned in this study, the main parameters that have limited or encouraged the use of these fluids are also identified and debated. Finally, the discussions presented in this review will inspire and guide researchers in developing new techniques to improve the applications of NFs in several fields.This research was partially funded by the Portuguese national funds of FCT/MCTES (PIDDAC) through the base funding from the following research units: UIDB/00690/2020 (CIMO), UIDB/04077/2020 (MEtRICs), and UIDB/00532/2020 (CEFT). The authors are also grateful for the funding of ANI and CIMO through the projects POCI-01-02B7-FEDER-069844 and CMFPE3- EXPL2021CIMO_01, respectively. The authors also acknowledge partial financial support from the project NORTE-01-0145-FEDER-030171 (PTDC/EMD-EMD/30171/2017), PTDC/EME-TED/7801/ 2020 and EXPL/EME-EME/0732/2021 funded by the NORTE 2020 Portugal Regional Operational Programme, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) and by Fundação para a Ciência e Tecnologia (FCT).info:eu-repo/semantics/publishedVersio

A contribuição do município de Guarulhos (estado de São Paulo) para a qualidade da água no Sistema Alto Tietê

The population growth in Guarulhos (São Paulo State) has been above the average for the São Paulo Metropolitan Region (RMSP). The Baquirivu-Guaçu River Basin (BHRBG), where the Baquirivu-Guaçu River is located, is exactly the urban expansion vector of Guarulhos municipality and neighboring areas. This study presents an analysis of the quality of the Baquirivu-Guaçu River waters at the entrance and at the exit of the Guarulhos municipality, in order to assess the effects of the implementation of sewage treatment plants (STPs) and land use on the Baquirivu-Guaçu River water quality between 2010 and 2014. For that were prepared the land use maps in the period analyzed, an analysis of the functioning of STPs in the study area, a statistical analysis of the Water Quality Index (WQI) and its parameters at different points of the river. The data relative to the Baquirivu-Guaçu River physico-chemicals and microbiological analyses indicate a much lower water quality in the exit of the Guarulhos municipality (WQI=16), when compared to that coming from the Arujá municipality (WQI=32). The mean values highlighted for BOD, DO, TU, TS and FC parameters indicate a considerable worsening of the Baquirivu-Guaçu River waters at point BQGU 03850. The values of TN, TP and pH parameters both at the entrance and exit of the basin are close. The analysis of land use evolution and water quality shows the consequences of an improper process of urban growth in the basin and that the domestic and industrial polluting sources represent considerable risk to water quality, attesting that the sanitation works carried out up to now have not been effective in reducing the polluting charges launched in the Baquirivu-Guaçu River waters.A contribuição do município de Guarulhos (Estado de São Paulo) para a qualidade de água do Sistema Alto Tietê. Guarulhos (SP) tem apresentado índices de crescimento populacional acima da média da Região Metropolitana de São Paulo (RMSP). A Bacia Hidrográfica do Rio Baquirivu Guaçu (BHRBG), onde se localiza o Rio Baquirivu Guaçu, é o vetor de expansão urbana do município e da região. Este trabalho apresenta uma análise da qualidade das águas do Rio Baquirivu-Guaçu na entrada e na saída do município de Guarulhos, avaliando os efeitos da implantação das ETEs e do uso da terra sobre a qualidade das águas do Rio Baquirivu-Guaçu, entre os anos de 2010 e 2014. Para isto foram elaborados os mapas de uso de terra no período analisado, uma análise do funcionamento das ETEs na área de estudo, e a análise estatística dos Índices de Qualidade de Águas (IQA) e de seus parâmetros nos diferentes pontos do rio. Os dados referentes às análises físico-química e microbiológica do Rio Baquirivu-Guaçu indicam uma qualidade de água na saída do município de Guarulhos (IQA=16), muito inferior àquela que recebe do município de Arujá (IQA=32). Os valores médios, em especial para os parâmetros DBO, OD, TU, ST e CF indicam uma piora na qualidade das águas do Rio Baquirivu-Guaçu no ponto BQGU03850. Os valores dos parâmetros NT, PT e pH foram muito próximos para ambos os pontos da entrada e saída da bacia. A análise entre a evolução do uso da terra e a qualidade da água demonstra as consequências do processo inadequado de crescimento urbano na bacia e que as fontes poluidoras domésticas e industriais representam considerável risco à qualidade das águas, demonstrando que as obras de saneamento realizadas até o momento não foram eficazes na redução de cargas poluidoras das águas do rio Baquirivu-Guaçu

A review of the advances and challenges in measuring the thermal conductivity of nanofluids

Fluids containing colloidal suspensions of nanometer-sized particles (nanofluids) have been extensively investigated in recent decades with promising results. Driven by the increase in the thermal conductivity of these new thermofluids, this topic has been growing in order to improve the thermal capacity of a series of applications in the thermal area. However, when it comes to measure nanofluids (NFs) thermal conductivity, experimental results need to be carefully analyzed. Hence, in this review work, the main traditional and new techniques used to measure thermal conductivity of the NFs are presented and analyzed. Moreover, the fundamental parameters that affect the measurements of the NFs’ thermal conductivity, such as, temperature, concentration, preparation of NFs, characteristics and thermophysical properties of nanoparticles, are also discussed. In this review, the experimental methods are compared with the theoretical methods and, also, a comparison between experimental methods are made. Finally, it is expected that this review will provide a guidance to researchers interested in implementing and developing the most appropriate experimental protocol, with the aim of increasing the level of reliability of the equipment used to measure the NFs thermal conductivity.This work has been funded by Portuguese national funds of FCT/MCTES (PIDDAC) through the base funding from the following research units: UIDB/00532/2020, UIDB/04077/2020, UIDP/04077/2020 and UIDP/04436/2020. The authors are also grateful for the funding of FCT through the projects NORTE-01-0145-FEDER-030171, PTDC/EME-TED/7801/2020, POCI-01-0145- FEDER-016861, POCI-01-0145-FEDER-028159, funded by COMPETE2020, NORTE2020, PORTUGAL2020, and FEDER

Recent developments on the thermal properties, stability and applications of nanofluids in machining, solar energy and biomedicine

In this review work, the recent progress made in the use of nanofluids (NFs) applied in three specific areas will be presented: machining, solar energy, and biomedical engineering. Within this context, the discussions will be guided by emphasizing the thermal and stability properties of these fluids. In machining, NFs play a prominent role in the processes of turning, milling, drilling, and grinding, being responsible for their optimization as well as improving the useful life of the tools and reducing costs. In the solar energy field, NFs have been used in the thermal management of the panels, controlling and homogenizing the operating temperature of these systems. In the biomedical area, the advantages of using NFs come from the treatment of cancer cells, the development of vaccines before the improvement of diagnostic imaging, and many others. In all lines of research mentioned in this study, the main parameters that have limited or encouraged the use of these fluids are also identified and debated. Finally, the discussions presented in this review will inspire and guide researchers in developing new techniques to improve the applications of NFs in several fields.This research was partially funded by the Portuguese national funds of FCT/MCTES (PIDDAC) through the base funding from the following research units: UIDB/00690/2020 (CIMO), UIDB/04077/2020 (MEtRICs), and UIDB/00532/2020 (CEFT). The authors are also grateful for the funding of ANI and CIMO through the projects POCI-01-02B7-FEDER-069844 and CMFPE3- EXPL2021CIMO_01, respectively. The authors also acknowledge partial financial support from the project NORTE-01-0145-FEDER-030171 (PTDC/EMD-EMD/30171/2017), PTDC/EME-TED/7801/ 2020 and EXPL/EME-EME/0732/2021 funded by the NORTE 2020 Portugal Regional Operational Programme, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) and by Fundação para a Ciência e Tecnologia (FCT)

Apolipoprotein E4 influences growth and cognitive responses to micronutrient supplementation in shantytown children from northeast Brazil

OBJECTIVE: Apolipoprotein E4 may benefit children during early periods of life when the body is challenged by infection and nutritional decline. We examined whether apolipoprotein E4 affects intestinal barrier function, improving short-term growth and long-term cognitive outcomes in Brazilian shantytown children. METHODS: A total of 213 Brazilian shantytown children with below-median height-for-age z-scores (HAZ) received 200,000 IU of retinol (every four months), zinc (40 mg twice weekly), or both for one year, with half of each group receiving glutamine supplementation for 10 days. Height-for-age z-scores, weight-for-age z-scores, weight-forheight z-scores, and lactulose:mannitol ratios were assessed during the initial four months of treatment. An average of four years (range 1.4-6.6) later, the children underwent cognitive testing to evaluate non-verbal intelligence, coding, verbal fluency, verbal learning, and delayed verbal learning. Apolipoprotein E4 carriage was determined by PCR analysis for 144 children. RESULTS: Thirty-seven children were apolipoprotein E4(+), with an allele frequency of 13.9%. Significant associations were found for vitamin A and glutamine with intestinal barrier function. Apolipoprotein E4(+) children receiving glutamine presented significant positive Pearson correlations between the change in height-for-age z-scores over four months and delayed verbal learning, along with correlated changes over the same period in weight-for-age z-scores and weight-for-height z-scores associated with non-verbal intelligence quotients. There was a significant correlation between vitamin A supplementation of apolipoprotein E4(+) children and improved delta lactulose/mannitol. Apolipoprotein E4(-) children, regardless of intervention, exhibited negative Pearson correlations between the change in lactulose-to-mannitol ratio over four months and verbal learning and non-verbal intelligence. CONCLUSIONS: During development, apolipoprotein E4 may function concomitantly with gut-tropic nutrients to benefit immediate nutritional status, which can translate into better long-term cognitive outcomes

Apolipoprotein E4 influences growth and cognitive responses to micronutrient supplementation in shantytown children from northeast Brazil

OBJECTIVE: Apolipoprotein E4 may benefit children during early periods of life when the body is challenged by infection and nutritional decline. We examined whether apolipoprotein E4 affects intestinal barrier function, improving short-term growth and long-term cognitive outcomes in Brazilian shantytown children. METHODS: A total of 213 Brazilian shantytown children with below-median height-for-age z-scores (HAZ) received 200,000 IU of retinol (every four months), zinc (40 mg twice weekly), or both for one year, with half of each group receiving glutamine supplementation for 10 days. Height-for-age z-scores, weight-for-age z-scores, weight-forheight z-scores, and lactulose:mannitol ratios were assessed during the initial four months of treatment. An average of four years (range 1.4-6.6) later, the children underwent cognitive testing to evaluate non-verbal intelligence, coding, verbal fluency, verbal learning, and delayed verbal learning. Apolipoprotein E4 carriage was determined by PCR analysis for 144 children. RESULTS: Thirty-seven children were apolipoprotein E4(+), with an allele frequency of 13.9%. Significant associations were found for vitamin A and glutamine with intestinal barrier function. Apolipoprotein E4(+) children receiving glutamine presented significant positive Pearson correlations between the change in height-for-age z-scores over four months and delayed verbal learning, along with correlated changes over the same period in weight-for-age z-scores and weight-for-height z-scores associated with non-verbal intelligence quotients. There was a significant correlation between vitamin A supplementation of apolipoprotein E4(+) children and improved delta lactulose/mannitol. Apolipoprotein E4(-) children, regardless of intervention, exhibited negative Pearson correlations between the change in lactulose-to-mannitol ratio over four months and verbal learning and non-verbal intelligence. CONCLUSIONS: During development, apolipoprotein E4 may function concomitantly with gut-tropic nutrients to benefit immediate nutritional status, which can translate into better long-term cognitive outcomes

Numerical optimization of a microchannel geometry for nanofluid flow and heat dissipation assessment

In this study, a numerical approach was carried out to analyze the effects of different geometries of microchannel heat sinks on the forced convective heat transfer in single-phase flow. The simulations were performed using the commercially available software COMSOLMultiphysics 5.6® (Burlington, MA, USA) and its results were compared with those obtained from experimental tests performed in microchannel heat sinks of polydimethylsiloxane (PDMS). Distilled water was used as the working fluid under the laminar fluid flow regime, with a maximum Reynolds number of 293. Three sets of geometries were investigated: rectangular, triangular and circular. The different configurations were characterized based on the flow orientation, type of collector and number of parallel channels. The main results show that the rectangular shaped collector was the one that led to a greater uniformity in the distribution of the heat transfer in the microchannels. Similar results were also obtained for the circular shape. For the triangular geometry, however, a disturbance in the jet impingement was observed, leading to the least uniformity. The increase in the number of channels also enhanced the uniformity of the flow distribution and, consequently, improved the heat transfer performance, which must be considered to optimize new microchannel heat sink designs. The achieved optimized design for a heat sink, with microchannels for nanofluid flow and a higher heat dissipation rate, comprised a rectangular collector with eight microchannels and vertical placement of the inlet and outlet.This work has been funded by Portuguese national funds of FCT/MCTES (PIDDAC) through base funding from the following research units: UIDB/00532/2020 (Transport Phenomena Research Center-CEFT), UIDB/04077/2020 (MEtRICs) and UIDP/04436/2020. The authors are also grateful for the funding of Fundação para a Ciência e a Tecnologia-FCT through the projectsLISBOA-01-0145-FEDER-030171/NORTE-01-0145-FEDER-030171 (PTDC/EMESIS/30171/2017), funded by COMPETE2020, NORTE2020, PORTUGAL2020, and FEDER. The authors also acknowledge FCT for partially financing the research under the framework of the project JICAM/0003/2017. Finally, I. Gonçalves acknowledges FCT for supporting her PhD fellowship, ref.: 2020.08646.B

Biopolymer-based membranes associated with osteogenic growth peptide for guided bone regeneration

Barrier membranes for guided bone regeneration (GBR) mainly promote mechanical maintenance of bone defect space and induce osteopromotion. Additionally, biopolymer-based membranes may provide greater bioactivity and biocompatibility due to their similarity to extracellular matrix (ECM).In this study, biopolymers-based membranes from bacterial cellulose (BC) and collagen (COL) associated with osteogenic growth peptide (OGP(10–14)) were evaluated to determine in vitro osteoinductive potential in early osteogenesis; moreover, histological study was performed to evaluate the BC–COL OGP(10–14) membranes on bone healing after GBR in noncritical defects in rat femur. The results showed that the BC–COL and BC–COL OGP(10–14) membranes promoted cell proliferation and alkaline phosphatase activity in osteoblastic cell cultures. However, ECMmineralization was similar between cultures grown on BC OGP(10–14) and BC–COL OGP(10–14) membranes. In vivo results showed that all the membranes tested, including the peptide-free BC membrane, promoted better bone regeneration than control group. Furthermore, the BC–COL OGP(10–14) membranes induced higher radiographic density in the repaired bone than the other groups at 1, 4 and 16 weeks. Histomorpho-metric analyses revealed that the BC–COL OGP(10–14) induced higher percentage of bone tissue in the repaired area at 2 and 4 weeks than others membranes. In general, these biopolymer-based membranes might be potential candidates for bone regeneration applications