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1.
Sensors (Basel) ; 23(6)2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36992033

RESUMO

We report the design and testing of a sensor pad based on optical and flexible materials for the development of pressure monitoring devices. This project aims to create a flexible and low-cost pressure sensor based on a two-dimensional grid of plastic optical fibers embedded in a pad of flexible and stretchable polydimethylsiloxane (PDMS). The opposite ends of each fiber are connected to an LED and a photodiode, respectively, to excite and measure light intensity changes due to the local bending of the pressure points on the PDMS pad. Tests were performed in order to study the sensitivity and repeatability of the designed flexible pressure sensor.

2.
J Ultrasound Med ; 41(11): 2897-2905, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35170800

RESUMO

To properly diagnose and treat injuries to the ankle or foot, the physician must have good anatomical knowledge of the ligaments involved. The bundles can be distinguished and identified by ultrasound examination of the medial aspect, but this may be a challenging task. In the present illustrated study, we discuss how a detailed ultrasound examination can be made of the different ligaments within the medial aspect of the ankle and foot.


Assuntos
Tornozelo , Ligamentos Articulares , Humanos , Tornozelo/diagnóstico por imagem , Ligamentos Articulares/diagnóstico por imagem , Ligamentos Articulares/lesões , Articulação do Tornozelo/diagnóstico por imagem , Ultrassonografia , Extremidade Inferior
3.
J Sports Sci ; 40(3): 248-270, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34720045

RESUMO

This study systematically reviewed and quantified the effects of running a long-distance race (LDR) on heart rate variability (HRV) and arterial stiffness (AS). All types of races of a distance equal to or greater than a marathon (≥42.2 km) were included. A total of 2,220 articles were identified, 52 were included in the qualitative analysis, and 48 were meta-analysed. The standardised mean difference pre- and post-race of various time-domain and frequency-domain indices of HRV, mean arterial blood pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP) and carotid-femoral pulse wave velocity (cfPWV) was calculated. Regarding HRV, there was a significant decrease in most of the variables considered as markers of parasympathetic activity, indicating a shift of autonomic balance towards a reduced vagal tone. Regarding vascular variables, there was a significant drop in blood pressure and reduced AS. In conclusion, running an LDR seems to have a considerable acute effect on the autonomic nervous system, haemodynamics, and vascular properties. The observed effects could be categorised within the expected acute responses to long-lasting, strenuous exercise.


Assuntos
Rigidez Vascular , Sistema Nervoso Autônomo , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Análise de Onda de Pulso , Rigidez Vascular/fisiologia
4.
Int J Mol Sci ; 24(1)2022 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-36614090

RESUMO

It has become more widely available to use biopolymer-based films as alternatives to conventional plastic-based films due to their non-toxic properties, flexibility, and affordability. However, they are limited in application due to deficiencies in their properties. The marine collagen was the specimen for the present study. Thus, the main objective was to reinforce marine collagen-based films with 1.0% (w/w of the dry polymer weight) of iron oxide nanoparticles (IO-NPs), graphene oxide nanoparticles (GO-NPs), or a combination of both oxides (GO-NPs/IO-NPs) as antibacterial and antioxidant additives to overcome some of the limitations of the film. In this way, the nanoparticles were incorporated into the film-forming solution (2% w/v in acetic acid, 0.05 M) and processed by casting. Thereafter, the films were dried and analyzed for their physicochemical, mechanical, microstructural, and functional properties. The results show that the effective combination of GO-NPs/IO-NPs enhanced the physicochemical properties by increasing the water contact angle (WCA) of the films from 77.2 to 84.4° and their transparency (T) from 0.5 to 5.2. Furthermore, these nanoparticles added antioxidant and antibacterial value to the films, with free radical inhibition of up to 95.8% and 23.8 mm of bacteria growth inhibition (diameter). As a result, both types of nanoparticles are proposed as suitable additives to be incorporated into films and enhance their different properties.


Assuntos
Grafite , Nanopartículas , Grafite/farmacologia , Grafite/química , Antioxidantes/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Colágeno , Nanopartículas Magnéticas de Óxido de Ferro
5.
Breast Cancer Res Treat ; 187(1): 237-244, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33389398

RESUMO

PURPOSE: Metastatic pattern (MP) is a prognostic factor in women with breast cancer. However, the prognostic significance of MP in male breast cancer patients remains unknown. METHODS: Using the SEER database, we gathered demographic information and disease characteristics for men diagnosed with de novo metastatic breast cancer from 2010 to 2017. Metastases to bone, brain, liver, and lung were used to define MP (bone-only, visceral, bone and visceral [BV], or other). Statistical analyses were performed to identify associations between overall survival (OS) and MP, as well as other patient and tumor features. We used multivariate logistic regression to evaluate factors associated with sites of metastases. RESULTS: We included 250 patients. MP distribution was bone = 38.8%, visceral = 14.8%, BV = 33.2%, and other = 13.2%. Median OS for each was bone = 33 months, visceral = 23 months, BV = 20 months, and other = 46 months (p = 0.046). Patients with brain metastases had significantly shorter OS compared with no brain metastases (median OS = 9 months vs. 30 months; p < 0.001). Compared with other subtypes, triple negative had the shortest OS (median 9 months, p < 0.001). Logistic regression modeling revealed that compared with HR+/HER2- breast cancers, HR-/HER2+ had higher odds of liver metastases and triple negative had higher odds of brain metastases. Patients younger than 50 years had a significantly greater risk of developing brain metastases. CONCLUSIONS: MP and tumor subtype can predict OS outcomes in men with metastatic breast cancer at diagnosis. Brain metastases confer very poor prognosis.


Assuntos
Neoplasias Ósseas , Neoplasias da Mama Masculina , Neoplasias da Mama , Neoplasias Ósseas/epidemiologia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama Masculina/epidemiologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Prognóstico , Receptor ErbB-2 , Estudos Retrospectivos
6.
Molecules ; 26(23)2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34885852

RESUMO

Along with rapid social development, the use of insecticides and caffeine-containing products increases, a trend that is also reflected in the composition of surface waters. This study is focused on the phototreatment of a surface water containing three neonicotinoids (imidacloprid, thiamethoxam, and clothianidin) and caffeine. Firstly, the radiation absorption of the target pollutants and the effect of the water matrix components were evaluated. It was observed that the maximum absorption peaks appear at wavelengths ranging from 246 to 274 nm, and that the water matrix did not affect the efficiency of the removal of the target pollutants. It was found that the insecticides were efficiently removed after a very short exposure to UV irradiation, while the addition of hydrogen peroxide was needed for an efficient caffeine depletion. The electrical energy per order was estimated, being the lowest energy required (9.5 kWh m-3 order-1) for the depletion of thiamethoxan by indirect photolysis, and a concentration of hydrogen peroxide of 5 mg dm-3. Finally, a preliminary evaluation on the formation of by-products reveals that these compounds play a key role in the evolution of the ecotoxicity of the samples, and that the application of direct photolysis reduces the concentration of these intermediates.

7.
Biol Chem ; 400(12): 1583-1591, 2019 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-31125311

RESUMO

The use of collagen and gelatin in the field of regenerative medicine is widely extended. However, most of the studies in this topic are focused on the scaffolds' properties, but only a few are related to the properties of the raw material used. The raw material analysis not only consists of a study of the composition, but also of the denaturation degree that can influence the processing and properties of the structure of the scaffold. Thus, the denaturation degree analysis of different collagen proteins was performed and assessed by the comparison of four different methods: differential scanning calorimetry (DSC), Fourier transform Infrared Spectroscopy (FTIR) and circular dichroism (CD) spectra and sulfhydryls content analysis. DSC measurements put forward a glass transition between 88°C and 95°C as well as from the FTIR measurements; the characteristic peaks for proteins are evidenced. However, from the sulfur content, only a small proportion of free sulfhydryls are present with respect to their total amount. In addition, CD spectra allow to estimate the secondary structure of the protein by the analysis of the α-helix and ß-strand and also quantify the denaturation degree with the 'positive/negative ratio' (RPN) from the CD profiles, obtaining values in the range between 25% and 100%.


Assuntos
Colágeno/análise , Colágeno/química , Varredura Diferencial de Calorimetria , Dicroísmo Circular , Eletroforese em Gel de Poliacrilamida , Gelatina/análise , Desnaturação Proteica , Dodecilsulfato de Sódio/química , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Appl Environ Microbiol ; 85(2)2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30389770

RESUMO

The facultative anaerobe Thauera aromatica strain AR-1 uses 3,5-dihydroxybenzoate (3,5-DHB) as a sole carbon and energy source under anoxic conditions using an unusual oxidative strategy to overcome aromatic ring stability. A 25-kb gene cluster organized in four main operons encodes the anaerobic degradation pathway for this aromatic. The dbdR gene coding for a LysR-type transcriptional regulator (LTTR), which is present at the foremost end of the cluster, is required for anaerobic growth on 3,5-DHB and for the expression of the main pathway operons. A model structure of DbdR showed conserved key residues for effector binding with its closest relative TsaR for p-toluenesulfonate degradation. We found that DbdR controlled expression of three promoters upstream from the operons coding for the three main steps of the pathway. While one of them (P orf20 ) was only active in the presence of 3,5-DHB, the other two (P dbhL and P orf18 ) showed moderate basal levels that were further induced in the presence of the pathway substrate, which needed be converted to hydroxyhydroquinone to activate transcription. Both basal and induced activities were strictly dependent on DbdR, which was also required for transcription from its own promoter. DbdR basal expression was moderately high and, unlike most LTTR, increased 2-fold in response to the presence of the effector. DbdR was found to be a tetramer in solution, producing a single retardation complex in binding assays with the three enzymatic promoters, consistent with its tetrameric structure. The three promoters had a conserved organization with a clear putative primary (regulatory) binding site and a putative secondary (activating) binding site positioned at the expected distances from the transcription start site. In contrast, two protein-DNA complexes were observed for the P dbdR promoter, which also showed significant sequence divergence from those of the three other promoters. Taken together, our results show that a single LTTR coordinately controls expression of the entire 3,5-DHB anaerobic degradation pathway in Thauera aromatica AR-1, allowing a fast and optimized response to the presence of the aromatic.IMPORTANCEThauera aromatica AR-1 is a facultative anaerobe that is able to use 3,5-dihydroxybenzoat (3,5-DHB) as the sole carbon and energy source in a process that is dependent on nitrate respiration. We have shown that a single LysR-type regulator with unusual properties, DbdR, controls the expression of the pathway in response to the presence of the substrate; unlike other regulators of the family, DbdR does not repress but activates its own synthesis and is able to bind and activate three promoters directing the synthesis of the pathway enzymes. The promoter architecture is conserved among the three promoters but deviates from that of typical LTTR-dependent promoters. The substrate must be metabolized to an intermediate compound to activate transcription, which requires basal enzyme levels to always be present. The regulatory network present in this strain is designed to allow basal expression of the enzymatic machinery, which would rapidly metabolize the substrate when exposed to it, thus rendering the effector molecule. Once activated, the regulator induces the synthesis of the entire pathway through a positive feedback, increasing expression from all the target promoters to allow maximum growth.


Assuntos
Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Hidroxibenzoatos/metabolismo , Resorcinóis/metabolismo , Thauera/genética , Fatores de Transcrição/genética , Transcrição Gênica , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Alinhamento de Sequência , Thauera/metabolismo , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
9.
J Sci Food Agric ; 99(10): 4825-4832, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30977138

RESUMO

BACKGROUND: The use of superabsorbent materials in horticulture has spread recently. These materials, which can retain water and release it as crops need it, have strong advantages such as the efficient use of water in periods of drought. However, these materials are made of synthetic polymers, which present problems of degradability and, sometimes, toxicity. For this reason, the main objective of this work is the development of biodegradable superabsorbent bioplastic (SAB) matrices using a soy protein isolate (SPI) as raw material. Zinc is also incorporated into these bioplastic matrices as an essential micronutrient for plants, to increase their added value. RESULTS: The incorporation of zinc chelated with 2,2',2″,2‴-(Ethene-1,2-diyldinitrilo)tetraacetic acid (Zn EDTA) (a salt with which the micronutrient is incorporated) into soy protein-based bioplastic matrices improved their superabsorbent capacity and provided a controlled release of water and nutrients to the crops. CONCLUSIONS: The results show the strong potential for the use of these bioplastic matrices in horticulture as superabsorbent materials that can release nutrients in a controlled manner. © 2019 Society of Chemical Industry.


Assuntos
Plásticos Biodegradáveis/química , Proteínas de Soja/química , Zinco/química , Adsorção , Plásticos Biodegradáveis/síntese química , Biotecnologia , Jardins , Micronutrientes/química , Água/química
10.
Sensors (Basel) ; 18(2)2018 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-29382078

RESUMO

This paper presents a high performance vision-based system with a single static camera for traffic surveillance, for moving vehicle detection with occlusion handling, tracking, counting, and One Class Support Vector Machine (OC-SVM) classification. In this approach, moving objects are first segmented from the background using the adaptive Gaussian Mixture Model (GMM). After that, several geometric features are extracted, such as vehicle area, height, width, centroid, and bounding box. As occlusion is present, an algorithm was implemented to reduce it. The tracking is performed with adaptive Kalman filter. Finally, the selected geometric features: estimated area, height, and width are used by different classifiers in order to sort vehicles into three classes: small, midsize, and large. Extensive experimental results in eight real traffic videos with more than 4000 ground truth vehicles have shown that the improved system can run in real time under an occlusion index of 0.312 and classify vehicles with a global detection rate or recall, precision, and F-measure of up to 98.190%, and an F-measure of up to 99.051% for midsize vehicles.

11.
Breast Cancer Res Treat ; 161(3): 537-548, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27975154

RESUMO

PURPOSE: To analyze the prognostic influence of metastatic pattern (MP) compared with other biologic and clinical factors in stage IV breast cancer at initial diagnosis (BCID) and evaluate factors associated with specific sites of metastases (SSM). METHODS: We evaluated women with stage IV BCID with known metastatic sites, reported to the Surveillance, Epidemiology and End Results program from 2010 to 2013. MP was categorized as bone-only, visceral, bone and visceral (BV), and other. Univariate and multivariate analyses determined the effects of each variable on overall survival (OS). Logistic regression examined factors associated with SSM. RESULTS: We included 9143 patients. Bone represented 37.5% of patients, visceral 21.9%, BV 28.8%, and other 11.9%. Median OS by MP was as follows: bone 38 months, visceral 21 months, BV 19 months, and other 33 months (P < 0.0001). Univariate analysis showed that higher number of metastatic sites had worse prognosis. In multivariate analysis, older age (hazard ratio 1.9), black race (hazard ratio 1.17), grade 3/4 tumors (hazard ratio 1.6), triple-negative (hazard ratio 2.24), BV MP (hazard ratio 2.07), and unmarried patients (hazard ratio 1.25) had significantly shorter OS. As compared with HR+/HER2- tumors, triple-negative and HR-/HER2+ had higher odds of brain, liver, lung, and other metastases. HR+/HER2+ had higher odds of liver metastases. All three subtypes had lower odds of bone metastases. CONCLUSIONS: There were substantial differences in OS according to MP. Tumor subtypes have a clear influence among other factors on SSM. We identified several prognostic factors that could guide therapy selection in treatment naïve patients.


Assuntos
Neoplasias da Mama/diagnóstico , Neoplasias da Mama/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Ósseas/secundário , Neoplasias Encefálicas/secundário , Neoplasias da Mama/mortalidade , Neoplasias da Mama/terapia , Feminino , Humanos , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Gradação de Tumores , Metástase Neoplásica , Estadiamento de Neoplasias , Prognóstico , Fatores de Risco , Programa de SEER , Adulto Jovem
12.
J Sci Food Agric ; 97(8): 2671-2674, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27664795

RESUMO

BACKGROUND: In the present work, bioplastics from renewable polymers were studied in order to reduce the huge generation of plastic wastes, causing an environmental problem that continues owing to the increasing demand for plastic products. RESULTS: Bioplastics with much better antimicrobial properties, in particular against Gram-positive bacteria, were obtained with the addition of nisin to the initial protein/plasticizer mixture. However, the addition of nisin produces more rigid but less deformable bioplastics (higher Young's modulus but lower strain at break). CONCLUSION: The results obtained are useful to demonstrate the antimicrobial properties of pea protein-based bioplastics by adding nisin and make them suitable as potential candidates to replace conventional plastics in food packaging. © 2016 Society of Chemical Industry.


Assuntos
Antibacterianos/farmacologia , Contaminação de Alimentos/prevenção & controle , Embalagem de Alimentos/instrumentação , Nisina/farmacologia , Pisum sativum/química , Proteínas de Plantas/química , Plásticos/análise , Polímeros/síntese química , Antibacterianos/química , Contaminação de Alimentos/análise , Bactérias Gram-Positivas/efeitos dos fármacos , Nisina/química , Polímeros/química , Polímeros/farmacologia
14.
Int J Mol Sci ; 17(10)2016 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-27775603

RESUMO

SET (SE Translocation) protein carries out multiple functions including those for protein phosphatase 2A (PP2A) inhibition, histone modification, DNA repair, and gene regulation. SET overexpression has been detected in brain neurons of patients suffering Alzheimer's disease, follicle theca cells of Polycystic Ovary Syndrome (PCOS) patients, and ovarian cancer cells, indicating that SET may play a pathological role for these disorders. SET transcript 2, produced by a specific promoter, represents a major transcript variant in different cell types. In this study, we characterized the transcriptional activation of human SET transcript 2 promoter in HeLa cells. Promoter deletion experiments and co-transfection assays indicated that ZFX, the Zinc finger and X-linked transcription factor, was able to transactivate the SET promoter. A proximal promoter region containing four ZFX-binding sites was found to be critical for the ZFX-mediated transactivation. Mutagenesis study indicated that the ZFX-binding site located the closest to the transcription start site accounted for most of the ZFX-mediated transactivity. Manipulation of ZFX levels by overexpression or siRNA knockdown confirmed the significance and specificity of the ZFX-mediated SET promoter activation. Chromatin immunoprecipitation results verified the binding of ZFX to its cognate sites in the SET promoter. These findings have led to identification of ZFX as an upstream factor regulating SET gene expression. More studies are required to define the in vivo significance of this mechanism, and specifically, its implication for several benign and malignant diseases related to SET dysregulation.


Assuntos
Chaperonas de Histonas/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Regiões Promotoras Genéticas/genética , Fatores de Transcrição/metabolismo , Ativação Transcricional/genética , Sequência de Bases , Sítios de Ligação/genética , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Proteínas de Ligação a DNA , Regulação da Expressão Gênica/genética , Células HEK293 , Células HeLa , Chaperonas de Histonas/biossíntese , Chaperonas de Histonas/genética , Humanos , Fatores de Transcrição Kruppel-Like/genética , Ligação Proteica , Interferência de RNA , RNA Interferente Pequeno/genética , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética
15.
J Sci Food Agric ; 95(4): 679-87, 2015 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24909425

RESUMO

BACKGROUND: Protein has been investigated as a source for biodegradable polymeric materials. This work evaluates the development of plastic materials based on crayfish and glycerol blends, processed by injection moulding, as a fully biodegradable alternative to conventional polymer-based plastics. The effect of different additives, namely sodium sulfite or bisulfite as reducing agents, urea as denaturing agent and L-cysteine as cross-linking agent, is also analysed. RESULTS: The incorporation of any additive always yields an increase in energy efficiency at the mixing stage, but its effect on the mechanical properties of the bioplastics is not so clear, and even dampened. The additive developing a greater effect is L-cysteine, showing higher Young's modulus values and exhibiting a remnant thermosetting potential. Thus, processing at higher temperature yields a remarkable increase in extensibility. CONCLUSION: This work illustrates the feasibility of crayfish-based green biodegradable plastics, thereby contributing to the search for potential value-added applications for this by-product.


Assuntos
Proteínas de Artrópodes/química , Astacoidea/química , Plásticos Biodegradáveis/química , Resíduos Industriais/análise , Frutos do Mar , Animais , Plásticos Biodegradáveis/economia , Fenômenos Químicos , Reagentes de Ligações Cruzadas/química , Cisteína/química , Módulo de Elasticidade , Estudos de Viabilidade , Embalagem de Alimentos/economia , Indústria de Processamento de Alimentos/economia , Glicerol/química , Indicadores e Reagentes/química , Resíduos Industriais/economia , Fenômenos Mecânicos , Plastificantes/química , Desnaturação Proteica/efeitos dos fármacos , Substâncias Redutoras/química , Espanha , Resistência à Tração , Ureia/química
16.
Breast Cancer Res Treat ; 143(2): 313-23, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24327333

RESUMO

Neoadjuvant chemotherapy (NAC) allows direct evaluation of the tumor's sensitivity to therapy, eradication of micrometastatic disease and the possibility of performing breast conserving surgery. The aim of this study was to describe long-term results of NAC in stage III breast cancer patients. We evaluated 126 patients that participated in a phase II randomized trial of neoadjuvant FAC compared with CMF. Chemotherapy was administered for three cycles prior to definitive surgery and radiotherapy, and then for six cycles as adjuvant. Median follow-up was 4.5 years (range 0.2-16.4). Objective response rate (OR) was similar in both groups (61 % for FAC, 66 % for CMF, P = NS). There were no differences in median disease free survival (DFS) or overall survival (OS) (5.1 vs 3.3 years and 6.7 vs 6.3 years for FAC and CMF, respectively). After 16 years of follow-up, 53 patients are still alive. Multivariate analysis showed that the number of pathologically involved lymph nodes (pLN) was the only factor associated with both, DFS and OS (P = 0.0003 and P = 0.0005, respectively). Both regimens were well tolerated, CMF had higher incidence of grade 3-4 leukopenia, thrombocytopenia, and stomatitis, whereas alopecia was more common in FAC. To the best of our knowledge, this is the first study to report long-term outcomes of FAC and CMF in the neoadjuvant setting. Within the sensitivity of our study, both regimens showed similar OR, long-term toxicity, DFS, and OS rate at 16 years. After 5 years, the hazard of death seems to decline. The prolonged follow-up of this study provides a unique opportunity to evaluate factors that predict long-term outcomes. After 16 years of follow-up, the number of pLN remains the most powerful predictor of survival.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Metotrexato/uso terapêutico , Terapia Neoadjuvante/métodos , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias da Mama/mortalidade , Neoplasias da Mama/radioterapia , Neoplasias da Mama/cirurgia , Ciclofosfamida/efeitos adversos , Ciclofosfamida/uso terapêutico , Intervalo Livre de Doença , Doxorrubicina/efeitos adversos , Doxorrubicina/uso terapêutico , Feminino , Fluoruracila/efeitos adversos , Fluoruracila/uso terapêutico , Seguimentos , Humanos , Metástase Linfática/patologia , Mastectomia Segmentar , Metotrexato/efeitos adversos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/tratamento farmacológico , Estudos Prospectivos , Sobrevida , Adulto Jovem
17.
Ecology ; 95(5): 1141-52, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-25000746

RESUMO

Identifying factors that may be responsible for regulating the size of animal populations is a cornerstone in understanding population ecology. The main factors that are thought to influence population size are either resources (bottom-up), or predation (top-down), or interspecific competition (parallel). However, there are highly variable and often contradictory results regarding their relative strengths and influence. These varied results are often interpreted as indicating "shifting control" among the three main factors, or a complex, nonlinear relationship among environmental variables, resource availability, predation, and competition. We argue here that there is a "missing link" in our understanding of predator-prey dynamics. We explore whether the landscape-of-fear model can help us clarify the inconsistencies and increase our understanding of the roles, extent, and possible interactions of top-down, bottom-up, and parallel factors on prey population abundance. We propose two main predictions derived from the landscape-of-fear model: (1) for a single species, we suggest that as the makeup of the landscape of fear changes from relatively safe to relatively risky, bottom-up impacts switch from strong to weak as top-down impacts go from weak to strong; (2) for two or more species, interspecific competitive interactions produce various combinations of bottom-up, top-down, and parallel impacts depending on the dominant competing species and whether the landscapes of fear are shared or distinctive among competing species. We contend that these predictions could successfully explain many of the complex and contradictory results of current research. We test some of these predictions based on long-term data for small mammals from the Chihuahuan Desert in the United States, and Mexico. We conclude that the landscape-of-fear model does provide reasonable explanations for many of the reported studies and should be tested further to better understand the effects of bottom-up, top-down, and parallel factors on population dynamics.


Assuntos
Dipodomys/fisiologia , Medo , Modelos Biológicos , Comportamento Predatório , Animais , Ecossistema , Plantas , Densidade Demográfica
18.
Biomimetics (Basel) ; 9(2)2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38392116

RESUMO

New advances in materials science and medicine have enabled the development of new and increasingly sophisticated biomaterials. One of the most widely used biopolymers is polycaprolactone (PCL) because it has properties suitable for biomedical applications, tissue engineering scaffolds, or drug delivery systems. However, PCL scaffolds do not have adequate bioactivity, and therefore, alternatives have been studied, such as mixing PCL with bioactive polymers such as gelatin, to promote cell growth. Thus, this work will deal with the fabrication of nanofiber membranes by means of the electrospinning technique using PCL-based solutions (12 wt.% and 20 wt.%) and PCL with gelatin (12 wt.% and 8 wt.%, respectively). Formic acid and acetic acid, as well as mixtures of both in different proportions, have been used to prepare the preliminary solutions, thus supporting the electrospinning process by controlling the viscosity of the solutions and, therefore, the size and uniformity of the fibers. The physical properties of the solutions and the morphological, mechanical, and thermal properties of the membranes were evaluated. Results demonstrate that it is possible to achieve the determined properties of the samples with an appropriate selection of polymer concentrations as well as solvents.

19.
Materials (Basel) ; 17(12)2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38930221

RESUMO

Antibiotic resistance is a global health crisis caused by the overuse and misuse of antibiotics. Accordingly, bacteria have developed mechanisms to resist antibiotics. This crisis endangers public health systems and medical procedures, underscoring the urgent need for novel antimicrobial agents. This study focuses on the green synthesis of ZnO nanoparticles (NPs) using aqueous extracts from Nepeta nepetella subps. amethystine leaves and stems, employing different zinc sulfate concentrations (0.5, 1, and 2 M). NP characterization included transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD), along with Fourier transform infrared spectroscopy (FTIR) analysis. This study aimed to assess the efficacy of ZnO NPs, prepared at varying concentrations of zinc sulfate, for their capacity to inhibit both Gram-positive and Gram-negative bacteria, as well as their antioxidant potential using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. SEM and TEM results showed predominantly spherical NPs. The smallest size (18.5 ± 1.3 nm for leaves and 18.1 ± 1.3 nm for stems) occurred with the 0.5 M precursor concentration. These NPs also exhibited remarkable antibacterial activity against both Gram-positive and Gram-negative bacteria at 10 µg/mL, as well as the highest antioxidant activity, with an IC50 (the concentration of NPs that scavenge 50% of the initial DPPH radicals) of 62 ± 0.8 (µg/mL) for the leaves and 35 ± 0.6 (µg/mL) for the stems. NPs and precursor concentrations were modeled to assess their impact on bacteria using a 2D polynomial equation. Response surface plots identified optimal concentration conditions for antibacterial effectiveness against each species, promising in combating antibiotic resistance.

20.
Int J Biol Macromol ; 268(Pt 2): 131599, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38626840

RESUMO

Phycocyanin (PC), a protein derived from algae, is non-toxic and biocompatible. Due to its environmental and sustainable properties, it has been studied as an alternative stabilizer for food emulsions. In this sense, the main objective of this work is to evaluate the effectiveness of PC and its use in combination with diutan gum (DG), a biological macromolecule, to prepare emulgels formulated with avocado oil. Z-potential measurements show that the optimum pH for working with PC is 2.5. Furthermore, the system exhibited a structured interface at this pH. The surface tension did not decrease further above 1.5 wt% PC. Interestingly, emulsions formulated with >1.5 wt% PC showed recoalescence immediately after preparation. Although 1.5 wt% had the smallest droplet size, this emulsion underwent creaming due to the low viscosity of the system. DG was used in combination with PC to increase viscosity and reduce creaming. As little as 0.1 wt% DG was sufficient to form an emulgel when incorporated into the previous emulsion, which exhibited pseudoplastic behaviour and viscoelastic properties with very low creaming rates. However, the use of PC in combination with DG resulted in a non-aggregated and stable emulgel with 1.5 wt% PC and 0.1 wt% DG.


Assuntos
Materiais Biocompatíveis , Emulsões , Ficocianina , Ficocianina/química , Emulsões/química , Viscosidade , Materiais Biocompatíveis/química , Géis/química , Concentração de Íons de Hidrogênio , Sistemas de Liberação de Medicamentos , Gomas Vegetais/química , Reologia , Tensão Superficial
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