602 research outputs found

    A review of hemorheology : measuring technologies and recent advances

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    Significant progress has been made over the years on the topic of hemorheology, not only in terms of the development of more accurate and sophisticated techniques, but also in terms of understanding the phenomena associated with blood components, their interactions and impact upon blood properties. The rheological properties of blood are strongly dependent on the interactions and mechanical properties of red blood cells, and a variation of these properties can bring further insight into the human health state and can be an important parameter in clinical diagnosis. In this article, we provide both a reference for hemorheological research and a resource regarding the fundamental concepts in hemorheology. This review is aimed at those starting in the field of hemodynamics, where blood rheology plays a significant role, but also at those in search of the most up-to-date findings (both qualitative and quantitative) in hemorheological measurements and novel techniques used in this context, including technical advances under more extreme conditions such as in large amplitude oscillatory shear flow or under extensional flow, which impose large deformations comparable to those found in the microcirculatory system and in diseased vessels. Given the impressive rate of increase in the available knowledge on blood flow, this review is also intended to identify areas where current knowledge is still incomplete, and which have the potential for new, exciting and useful research. We also discuss the most important parameters that can lead to an alteration of blood rheology, and which as a consequence can have a significant impact on the normal physiological behavior of blood

    The effect of insulin-loaded chitosan particle-aggregated scaffolds in chondrogenic differentiation

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    Osteochondral defect repair requires a tissue engineering approach that aims at mimicking the physiological properties and structure of two different tissues (cartilage and bone) using a scaffold–cell construct. One ideal approach would be to engineer in vitro a hybrid material using a single-cell source. For that purpose, the scaffold should be able to provide the adequate biochemical cues to promote the selective but simultaneous differentiation of both tissues. In this work, attention was paid primarily to the chondrogenic differentiation by focusing on the development of polymeric systems that provide biomolecules release to induce chondrogenic differentiation. For that, different formulations of insulin-loaded chitosan particle–aggregated scaffolds were developed as a potential model system for cartilage and osteochondral tissue engineering applications using insulin as a potent bioactive substance known to induce chondrogenic differentiation. The insulin encapsulation efficiency was shown to be high with values of 70.37!0.8%, 84.26!1.76%, and 87.23!1.58% for loadings of 0.05%, 0.5%, and 5%, respectively. The in vitro release profiles were assessed in physiological conditions mimicking the cell culture procedures and quantified by Micro-BCA! protein assay. Different release profiles were obtained that showed to be dependent on the initial insulin-loading percentage. Further, the effect on prechondrogenic ATDC5 cells was investigated for periods up to 4 weeks by studying the influence of these release systems on cell morphology, DNA and glycosaminoglycan content, histology, and gene expression of collagen types I and II, Sox-9, and aggrecan assessed by real-time polymerase chain reaction. When compared with control conditions (unloaded scaffolds cultured with the standard chondrogenic-inducing medium), insulin-loaded scaffolds upregulated the Sox-9 and aggrecan expression after 4 weeks of culture. From the overall results, it is reasonable to conclude that the developed loaded scaffolds when seeded with ATDC5 can provide biochemical cues for chondrogenic differentiation. Among the tested formulations, the higher insulin-loaded system (5%) was the most effective in promoting chondrogenic differentiation.The authors would like to acknowledge the Portuguese Foundation for Science and Technology for the Ph. D. Grant to Patricia B. Malafaya (SFRH/BD/11155/2002). This work was partially supported and carried out under the scope of the European STREP Project HIPPOCRATES (NMP3-CT-2003-505758) and European NoE EXPERTISSUES (NMP3CT-2004-500283). The authors also like to acknowledge the Life and Health Sciences Research Institute (ICVS), University of Minho, for the use of their facilities, namely, to Luis Martins for histological sections slicing and H&E stain processing

    Safe use of ozone gas in enamel adhesion

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    Purpose: Evaluate the shear bond strength of a self-etching system to enamel pretreated with ozone and its type of fracture. Matherial and methods: Thirty sound bovine incisors were bisected and polished just before the application of the adhesive system. The adhesion area was limited to a 3-mm diameter. The specimens were randomly assigned to the experimental groups (n = 15) and composite resin cylinders were added to the tested surfaces, after the application of the adhesive according to the manufacturer’s instructions. Group G1 (AdheSE® with ozone) was previously prepared with ozone gas from the HealOzone unit (Kavo®) for 20 s, groups G2 (AdheSE®) was used as control. The specimens were stored in distilled water for 24 h at 37 ◦C with 100% humidity, before being thermocycled. The type of fracture was analyzed under scanning electronic microscope and the data were submitted to Shapiro–Wilk, Student’s t-test and Chi-squared statistical analyses. Results: The mean bond strengths were G1: 15.0 MPa (77.8% of adhesive fractures between enamel and adhesive) and G2: 13.1 MPa (36.4% of adhesive fractures between enamel and adhesive). Conclusion: The shear bond strength of a self-etching system was not influenced by the previous application of ozone gas.Objectivo: Avaliar as forças de resistência adesiva de um sistema adesivo auto-condicionador no esmalte pré-tratado com ozono e o tipo de fractura. Material e métodos: Trinta incisivos hígidos de origem bovina foram seccionados de forma a separar a coroa da raiz e polidos antes da colocação do sistema adesivo. A área de adesão foi limitada a 3 mm de diâmetro. Os espécimes foram aleatoriamente divididos (n = 15) e cilindros de resina composta foram adicionados às superfícies de teste após cada sistema adesivo ter sido aplicado de acordo com as instruções do fabricante. O grupo G1 (AdheSE® com ozono) foi condicionado com gás de ozono gerado pelo aparelho HealOzone (Kavo®),durante 20 segundos, G2 (AdheSE®) funcionou como controlo. Os espécimes foram mantidos em água destilada durante 24 horas numa estufa a 37 ◦C com 100% de humidade, antes da termociclagem. O tipo de fractura analisado ao MEV e os dados submetidos à análise estatística Shapiro–Wilk, Student’s t-test e Chi-squared. Resultados: As médias de resistência adesiva foram: G1:15,0 MPa (77,8% de fracturas adesivas entre o esmalte e o adesivo) e G4: 13,1 MPa (36,4% de fracturas adesivas entre o esmalte e o adesivo). Conclusão: Os valores de resistência adesiva do sistema adesivo auto-condicionador não foram influenciados pela aplicação prévia de gás de ozono.info:eu-repo/semantics/publishedVersio

    Prospection and Evaluation of (Hemi) Cellulolytic Enzymes Using Untreated and Pretreated Biomasses in Two Argentinean Native Termites

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    Saccharum officinarum bagasse (common name: sugarcane bagasse) and Pennisetum purpureum (also known as Napier grass) are among the most promising feedstocks for bioethanol production in Argentina and Brazil. In this study, both biomasses were assessed before and after acid pretreatment and following hydrolysis with Nasutitermes aquilinus andCortaritermes fulviceps termite gut digestome. The chemical composition analysis of the biomasses after diluted acid pretreatment showed that the hemicellulose fraction was partially removed. The (hemi) cellulolytic activities were evaluated in bacterial culture supernatantsof termite gut homogenates grown in treated and untreated biomasses. In all cases, we detected significantly higher endoglucanase and xylanase activities using pretreated biomasses compared to untreated biomasses, carboxymethylcellulose and xylan. Several protein bands with (hemi) cellulolytic activity were detected in zymograms and two-dimensionalgel electrophoresis. Some proteins of these bands or spots were identified as xylanolytic peptides by mass spectrometry. Finally, the diversity of cultured cellulolytic bacterial endosymbionts associated to both Argentinean native termite species was analyzed. This study describes, for the first time, bacterial endosymbionts and endogenous (hemi) cellulases of two Argentinean native termites as well as their potential application in degradation of lignocellulosic biomass for bioethanol production.Fil: Ben Guerrero, Emiliano. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Arneodo Larochette, Joel Demián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Bombarda Campanha, Raquel. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Oliveira, Patrícia Abrão de. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Labate, Mônica T. Veneziano. Universidade de Sao Paulo; BrasilFil: Cataldi, Thaís Regiani. Universidade de Sao Paulo; BrasilFil: Campos, Eleonora. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cataldi, Ángel Adrián. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Labate, Carlos A.. Universidade de Sao Paulo; BrasilFil: Rodrigues, Clenilson Martins. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Talia, Paola Monica. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Pilot Study to Reduce Added Salt on a University Canteen through the Use of an Innovative Dosage Equipment

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    Background: This study aims to demonstrate the practical application of an innovative easy-to-use equipment to dosage cooking salt, and evaluate the effectiveness in reducing 30% of the added salt in meals and the impact on consumers satisfaction and food waste. Methods: Two canteens from one public university where randomized in one control arm and one intervention arm. The first step was to evaluate the salt added to food through atomic emission spectrophotometry in both canteens, and the second step was to perform gradual reductions of up to 30% of cooking salt in the intervention canteen using the Salt Control-C (SC-C) equipment. Consumer acceptability was assessed through satisfaction questionnaires and food waste was evaluated by weighing. Results: The intervention canteen achieved to a reduction of more than 30% of added salt in soup (34.3% per 100 g), fish dish (41.1% per 100 g) and meat dish (48.0% per 100 g), except for the vegetarian dish (6.1% per 100 g). There was no decrease in consumer satisfaction, with a significant satisfaction increase of 15.7% (p = 0.044) regarding the flavor of the main dish. Also, no significant differences were found in food waste. Conclusions: SC-C seems to be effective in reducing 30% of added salt levels in canteen meals, and may be a good strategy to control and reach adequate levels of added salt in meals served outside-the-home, promoting benefits to the individuals health. (c) 2022 by the authors. Licensee MDPI, Basel, Switzerland

    Antibodies to Toxoplasma gondii and Leishmania spp. in domestic cats from Luanda, Angola

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    Toxoplasma gondii and Leishmania spp. are zoonotic protozoa of importance to animal and public health. The present study aimed to assess for the first time the seroprevalence of these zoonotic parasites in a domestic feline population living in Luanda, Angola. One hundred and two cats were sampled at a veterinary medical centre, from May 2014 to February 2016. The age of the cats ranged from 2.5 to 143 months (median: 12 months; interquartile range: 7.5–24). Serum samples were tested for immunoglobulin (Ig) G antibodies to T. gondii at two-fold dilutions of 1:20 to 1:2560 with a modified agglutination test (MAT) commercial kit. The direct agglutination test (DAT) for titration of IgG antibodies specific to Leishmania spp. used a standard freeze-dried antigen at a concentration of 5 × 10 7 promastigotes per milliliter, following a predefined protocol. Two-fold dilution series ranging from 1:25 to 1:800 were tested, with a cut-off titre of 100 chosen for seropositivity. Four out of 102 cats (3.9%; 95% confidence interval [CI]: 1.1–9.7) had antibodies to T. gondii: one had a titer of 20, one a titer of 160, and two had a titer ≥ 2560. No cat (0.0%; CI: 0.0–3.5) was found seropositive for Leishmania spp. A statistically significant difference was found between T. gondii seroprevalence and Leishmania spp. seroprevalence (p = 0.043). The odds of a cat being seropositive to T. gondii increased by an average factor of 1.58 for each 1-year increase in age (p = 0.003). The sampled cats were well-cared animals and may not represent the overall feline population of Angola at the national and city levels. The fact that only 12 out of the 102 sampled cats ate or had access to raw or undercooked meat and/or viscera may have reduced the likelihood of finding seropositive results. Under these circumstances, additional studies, including a larger number of cats, are necessary for a more comprehensive assessment of the zoonotic risk posed by these animals in Angola.The authors would like to express their gratitude to Hugo Vilhena for his logistic support. This work was sponsored by the Foundation for Science and Technology (FCT), Ministry of Education and Science, Portugal, under the Projects UID/CVT/00772/2013 and UID/CVT/ 0772/2016.info:eu-repo/semantics/publishedVersio

    Innovative equipment to monitor and control salt usage when cooking at home: IMC SALT research protocol for a randomised controlled trial

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    Introduction Excessive salt intake is a public health concern due to its deleterious impact on health. Most of the salt consumed come from those that are added when cooking. This study will improve knowledge on the effectiveness of interventions to reduce salt consumption among consumers. Methods and analysis In this randomised clinical trial, we will be evaluating the efficacy of an intervention - the Salt Control H, an innovative prototype equipment to monitor and control use of salt when cooking - among workers from a public university, with the aim of reducing their dietary salt intake. We will randomly select 260 workers who meet the eligibility criteria and who are enrolled to an occupational health appointment and randomise them into one of the two arms of the study (either control or intervention), with matched baseline characteristics (sex and hypertension). The intervention will last for 8 weeks, during which the participants will use the equipment at home to monitor and control their use of salt when cooking. The main outcome will be 24-hour urinary sodium excretion at baseline, at fourth and eighth weeks of intervention, and at 6 months after intervention. Ethics and dissemination Ethical approval for the study has been obtained from the Ethics Committee of the Centro Hospitalar Universitário São João. The results of the investigation will be published in peer-reviewed scientific papers and presented at international conferences. Trial registration number NCT03974477 Equipment provisional patent number Registered at INPI: 20191000033265. (c) Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ

    Edible films and coatings formulated with arrowroot starch as a non-conventional starch source for plums packaging

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    Increasing environmental awareness has promoted an interest in alternative strategies to common plastics obtained from fossil sources, stimulating research on the use of biodegradable and edible films/coatings obtained from renewable sources such as arrowroot starch. This research work aimed to evaluate the use of arrowroot starch on the formation of edible films and coatings. Increasing the concentration of arrowroot starch (from 1% to 5%, mass/mass) in the film produced by casting resulted in increased water vapor permeability (from 2.20 to 3.68 g mm/m2 day kPa), moisture content (3.22% to 7.95%), increased thickness (from 0.029 to 0.101 mm), and decreased solubility in water (from 22.45% to 13.89%). The films were homogeneous, transparent and manageable, with the exception of the film with 1% starch. Film-forming solutions at concentrations of 0%, 2%, and 4% (mass/mass) of arrowroot starch were prepared and applied to plums to evaluate post-harvest behavior when stored at 25 and 5 ¿C for 35 days. The 2% coating adhered well to the plums’ surfaces, was bright and was effective in reducing mass loss and respiratory rate, associated with storage temperature of 5 ¿C. The 4% coating presented an opaque and flocculated appearancePostprint (published version
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