Raquel Barros Bernardino - Academia.edu (original) (raw)

Papers by Raquel Barros Bernardino

Biomedicines

Stress, as a physiological response, is a major factor that affects several processes, including ... more Stress, as a physiological response, is a major factor that affects several processes, including reproductive functions. The main hormonal players of stress are cortisol (humans) and corticosterone (rodents). Sertoli cells (SCs), as key contributors for the testicular homeostasis maintenance, are extensively challenged by different hormones, with glucocorticoid corticosterone being the signaling modulator that may impact these cells at different levels. We aimed to characterize how corticosterone modulates SCs energy balance, putting the mitochondrial performance and signaling output in perspective as the cells can disperse to the surroundings. TM4 mouse SCs were cultured in the absence and presence of corticosterone (in nM: 20, 200, and 2000). Cells were assessed for extracellular metabolic fluxes, mitochondrial performance (cell respirometry, mitochondrial potential, and mitochondrial complex expressions and activities), and the expression of androgen and corticosteroid receptors,...

Vitamins and Hormones

The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel responsible fo... more The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel responsible for the direct transport of bicarbonate and chloride. CFTR-dependent ionic transport is crucial for pH regulation and fluid homeodynamics among epithelial surfaces. Particularly, CFTR performs an essential role in the male reproductive tract, which requires a tight regulation of water and electrolytes in order to produce healthy spermatozoa. The absence or malfunction of CFTR results in cystic fibrosis, the most common lethal disease among Caucasians, that is characterized by an impaired fluid and ionic homeostasis in the whole organism. Due to the wide expression and importance of CFTR, the male reproductive tract is highly affected by cystic fibrosis, resulting in male infertility. Although CFTR is not permeable to water, this protein acts as a regulator of other protein channels, such as aquaporins. In fact, CFTR acts as a molecular partner of aquaporins in epithelial cells, regulating fluid homeodynamics. Herein, up-to-date data concerning the regulation of aquaporin-mediated water transport by CFTR will be discussed, highlighting the role of both channels in the male reproductive tract.

Journal of Cellular Physiology, 2020

The strong hormonal dysregulation associated with obesity is responsible for the disruption of se... more The strong hormonal dysregulation associated with obesity is responsible for the disruption of several reproductive events. Sertoli cells (SCs) function is dependent on energetic homeostasis and thus, directly associated with energy homeostasis regulating hormones. To further understand the influence of those hormones with SCs function and obesity, we hypothesize that human SCs express obesity‐related genes (ORG; MC4R, GNPDA2, TMEM18, and FTO) and that they respond to energy homeostasis regulating hormones (leptin, ghrelin, and glucagon‐like protein 1 [GLP‐1]) stimuli. To test our hypothesis, SCs were cultured with increasing doses of leptin (0, 5, 25, or 50 ng/ml, for 24 h), ghrelin (0, 20, 100, and 500 pM, for 24 h), and GLP‐1 (10, 1000, or 1 × 105 pM, for 6 h). The presence and abundance of ORG transcripts and proteins in SCs were accessed by polymerase chain reaction techniques, Western blot analysis, and immunofluorescence staining. Our results show that human SCs express MC4R, GNPDA2, TMEM18, and FTO in specific cellular locations. MC4R and FTO expression in human SCs was not responsive to the treatments. However, GNPDA2 and TMEM18 expression increased after exposure to the highest concentration of leptin and ghrelin, respectively. We highlight for the first time that human SCs express ORG and that these are responsive to energy homeostasis hormonal stimuli. GNPDA2 and TMEM18 expression respond in opposite directions according to overall energy status, mediated by energy homeostasis regulating hormones. Leptin and ghrelin control of ORG expression by human SCs can be associated with overweight‐related infertility and subfertility in males.

A cafeína é um componente comum do café, chá, bebidas energéticas, produtos que contenham cacau o... more A cafeína é um componente comum do café, chá, bebidas energéticas, produtos que contenham cacau ou chocolate e até mesmo de vários medicamentos. O consumo excessivo de cafeína tem sido associado a diversos problemas de foro reprodutivo. Além disso, foi demonstrado que este composto tem uma ação moduladora no metabolismo celular. Isto levou-nos a colocar a hipótese de a cafeína poder alterar o metabolismo das células de Sertoli humanas (hSCs), as quais são essenciais para a espermatogénese e para a fertilidade masculina. Para verificar esta hipótese, as hSCs foram cultivadas na presença de cafeína (5, 50 e 500 μM) e o seu perfil glicolítico foi avaliado através do estudo do consumo de glucose e da produção de lactato e alanina. Os níveis de expressão proteica dos transportadores de glucose (GLUT1 e GLUT3), fosfofrutoquinase 1 (PFK1), lactato desidrogenase (LDH) e transportador de monocarboxilatos 4 (MCT4) foram também determinados, assim como a atividade da enzima LDH. Para além diss...

As células de Sertoli (SCs) formam a barreira hematotesticular (BHT), controlando o microambiente... more As células de Sertoli (SCs) formam a barreira hematotesticular (BHT), controlando o microambiente onde a espermatogénese ocorre. O regulador de condutância transmembranar de fibrose cística (CFTR) tem um papel preponderante na fertilidade masculina, pois indivíduos com mutações no gene CFTR são normalmente sub-férteis ou inférteis. Para além de ser responsável pelo transporte de Cl-/HCO3-, o CFTR pode controlar o movimento de fluidos, regulando sistemas de transporte de água (Aquaporinas). [...]

A pioglitazona é um potente agonista sintético dos recetores ativados por proliferadores de perox... more A pioglitazona é um potente agonista sintético dos recetores ativados por proliferadores de peroxissoma gama utilizado para tratar a Diabetes Mellitus tipo 2 (DMT2). Outros benefícios para a utilização da pioglitazona têm sido reportados mas os seus efeitos na reprodução masculina permanecem desconhecidos. Além da pioglitazona, a metformina é uma biguanida usada como primeira linha no tratamento da DMT2. Ambos são utilizados na prática clínica como terapia combinada. [...]

Animals, 2022

Cryopreservation is globally used as a method for long-term preservation, although freeze-thawing... more Cryopreservation is globally used as a method for long-term preservation, although freeze-thawing procedures may strongly impair the gamete function. The correct cryopreservation procedure is characterized by the balance between freezing rate and cryoprotective agents (CPAs), which minimizes cellular dehydration and intracellular ice formation. For this purpose, osmoregulation is a central process in cryopreservation. During cryopreservation, water and small solutes, including penetrating cryoprotective agents, cross the plasma membrane. Aquaporins (AQPs) constitute a family of channel proteins responsible for the transport of water, small solutes, and certain gases across biological membranes. Thirteen homologs of AQPs (AQP0-12) have been described. AQPs are widely distributed throughout the male and female reproductive systems, including the sperm and oocyte membrane. The composition of the male and female gamete membrane is of special interest for assisted reproductive techniques...

The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement ... more The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement of several mechanisms, among which is included the transmembranous movement of H+ ions. Na+-H+ exchangers (SLC9, solute carrier 9 family members) are among the membrane transporters known to participate in intracellular and extracellular pH regulation but also have important roles in salt and water absorption across epithelia and in the regulation of cell volume. The presence of several Na+-H+ exchangers has been reported in the male reproductive tract. Their involvement in the processes that ensure the correct pursuance of the spermatogenetic event and spermatozoa maturation has been suggested. Indeed, the formation of mature spermatozoa is highly dependent on the maintenance of adequate ductal luminal milieu pH and ionic balance. Perturbations in these processes result in reduced male reproductive potential and consequently male subfertility and/or infertility. Thus, it is imperative t...

The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement ... more The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement of several mechanisms, among which is included the transmembranar movement of H + ions. Na + -H + exchangers (SLC9, solute carrier 9 family members) are amongst the membrane transporters known to participate in intracellular and extracellular pH regulation, but also have important roles on salt and water absorption across epithelia and on regulation of cell volume. The presence of several Na + -H + exchangers has been reported in the male reproductive tract. Their involvement in the processes that assure the correct pursuance of the spermatogenetic event and spermatozoa maturation has been suggested. Indeed, the formation of mature spermatozoa is highly dependent on the maintenance of adequate ductal luminal milieu pH and ionic balance. Perturbations in these processes result in reduced male reproductive potential and consequently male subfertility and/or infertility. Thus, it is imperat...

Introduction: Metabolic diseases are related with severe fertility problems, partly due to increa... more Introduction: Metabolic diseases are related with severe fertility problems, partly due to increased aromatization of androgens to estrogens. Elevated levels of 17β-Estradiol (E2) are known to cause alterations on normal development of germ cells, compromising spermatogenesis. Spermatogenesis is dependent on Sertoli cells (SCs) function, since these cells ensure an adequate environment inside the seminiferous tubule. Objective: To determine the impact of elevated levels of E2 on aquaglyceroporins (AQPs) expression and glycerol permeability in mouse SCs (mSCs, TM4 cell line). Material and Methods: The expression of AQP3, AQP7, AQP9, and AQP11 were identified by RT-PCR and immunofluorescence techniques. Then, the expression was evaluated by qRT-PCR. Glycerol permeability was evaluated by stopped flow light-scattering. Results: We were able to identify for the first time the expression of AQP3, AQP9 and AQP11 in mouse testis and mSCs. AQP9 was about six times more expressed than AQP3 a...

Free Radical Biology and Medicine, 2018

Tea (Camellia sinensis L.) is one of the most consumed beverages worldwide, not only due to its p... more Tea (Camellia sinensis L.) is one of the most consumed beverages worldwide, not only due to its pleasant organoleptic properties, but also to its antioxidant effects. The amino acid L-theanine, which is almost exclusively found in tea leaves, has demonstrated a protective role against oxidative damages in certain cell types. We hypothesized that L-theanine could maintain the in-vitro redox homeostasis of human Sertoli cells (hSCs). The proper functioning of these cells is essential for a successful sperm production. So, we evaluated the effect of L-theanine (50 μM) on the metabolism, mitochondrial functionality, and oxidative damages in hSCs. The exposure of hSCs to L-theanine resulted in an increased hSCs proliferation and a subsequent increase in glucose metabolization through glycolysis. In response to this metabolic adaptation, there was an increase in mitochondrial membrane potential, which could result in a redox imbalance. However, no alterations were observed in protein carb...

The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement ... more The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement of several mechanisms, among which is included the transmembranous movement of H ions. Na-H exchangers (SLC9, solute carrier 9 family members) are among the membrane transporters known to participate in intracellular and extracellular pH regulation but also have important roles in salt and water absorption across epithelia and in the regulation of cell volume. The presence of several Na-H exchangers has been reported in the male reproductive tract. Their involvement in the processes that ensure the correct pursuance of the spermatogenetic event and spermatozoa maturation has been suggested. Indeed, the formation of mature spermatozoa is highly dependent on the maintenance of adequate ductal luminal milieu pH and ionic balance. Perturbations in these processes result in reduced male reproductive potential and consequently male subfertility and/or infertility. Thus, it is imperative to und...

Reproductive BioMedicine Online, 2020

All data generated and analysed during the study are included in this published article. AUTHOR C... more All data generated and analysed during the study are included in this published article. AUTHOR CONTRIBUTIONS AR was responsible for experimental procedures, data analysis, critical discussion, manuscript draft and critical approval of the final article. CF assisted in the determination of spermiogram characteristics and critical approval of the final article. RB, MGA and PFO assisted in the determination of oxidative stress and metabolism and critical approval of the final article. PV was responsible for sperm sample preparation at the IVF clinic and critical approval of the final article. AB was responsible for patient recruitment and IVF laboratory supervision and critical approval of the final article. MS was responsible for data analysis, critical discussion and final manuscript writing. RS was responsible for study conception and design, supervision of experimental procedures, data analysis, critical discussion, manuscript writing and critical approval of the final article.

International Transactions in Operational Research, 2020

In this article, we address the family traveling salesman problem (FTSP), an NP-hard problem that... more In this article, we address the family traveling salesman problem (FTSP), an NP-hard problem that may be seen as a generalization of the traveling salesman problem. In the FTSP, the set of cities is partitioned into several families and one wants to find the minimum cost route that visits a given number of cities in each family. We propose two metaheuristics, a population-based method and a local search method, and a hybrid algorithm, which combines a branch-and-cut algorithm with a local search procedure. All the proposed methods improve the best known upper bounds from the literature. The local search method and the hybrid algorithm improve the best known upper bounds for all the benchmark instances with unknown optimal value, while the population-based method improves the best known upper bounds for all instances, except two. Furthermore, we developed an instance generator to create additional test instances with different visit patterns. These newly generated instances were considered in the computational experiment and, thus, we provide optimal values or upper bounds for each instance. Additionally, we created a website dedicated to the FTSP, where this information is made available to the scientific community (http://familytsp.rd.ciencias. ulisboa.pt/).

International Transactions in Operational Research, 2016

In this paper we address the traveling purchaser problem, an NP-hard problem that generalizes the... more In this paper we address the traveling purchaser problem, an NP-hard problem that generalizes the traveling salesman problem. We present several metaheuristics that combine genetic algorithms and local search. The genetic algorithms are induced by different hierarchic orderings of the decision making regarding the route and the acquisition of the items. Computational experiments were carried out with benchmark instances and the results show that the proposed metaheuristics are a suitable tool to solve high-dimensioned instances for which the exact methods do not provide solutions within a reasonable CPU time. For several instances, best new upper bounds for the optimum value of the objective function were obtained.

Biomedicines

Stress, as a physiological response, is a major factor that affects several processes, including ... more Stress, as a physiological response, is a major factor that affects several processes, including reproductive functions. The main hormonal players of stress are cortisol (humans) and corticosterone (rodents). Sertoli cells (SCs), as key contributors for the testicular homeostasis maintenance, are extensively challenged by different hormones, with glucocorticoid corticosterone being the signaling modulator that may impact these cells at different levels. We aimed to characterize how corticosterone modulates SCs energy balance, putting the mitochondrial performance and signaling output in perspective as the cells can disperse to the surroundings. TM4 mouse SCs were cultured in the absence and presence of corticosterone (in nM: 20, 200, and 2000). Cells were assessed for extracellular metabolic fluxes, mitochondrial performance (cell respirometry, mitochondrial potential, and mitochondrial complex expressions and activities), and the expression of androgen and corticosteroid receptors,...

Vitamins and Hormones

The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel responsible fo... more The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel responsible for the direct transport of bicarbonate and chloride. CFTR-dependent ionic transport is crucial for pH regulation and fluid homeodynamics among epithelial surfaces. Particularly, CFTR performs an essential role in the male reproductive tract, which requires a tight regulation of water and electrolytes in order to produce healthy spermatozoa. The absence or malfunction of CFTR results in cystic fibrosis, the most common lethal disease among Caucasians, that is characterized by an impaired fluid and ionic homeostasis in the whole organism. Due to the wide expression and importance of CFTR, the male reproductive tract is highly affected by cystic fibrosis, resulting in male infertility. Although CFTR is not permeable to water, this protein acts as a regulator of other protein channels, such as aquaporins. In fact, CFTR acts as a molecular partner of aquaporins in epithelial cells, regulating fluid homeodynamics. Herein, up-to-date data concerning the regulation of aquaporin-mediated water transport by CFTR will be discussed, highlighting the role of both channels in the male reproductive tract.

Journal of Cellular Physiology, 2020

The strong hormonal dysregulation associated with obesity is responsible for the disruption of se... more The strong hormonal dysregulation associated with obesity is responsible for the disruption of several reproductive events. Sertoli cells (SCs) function is dependent on energetic homeostasis and thus, directly associated with energy homeostasis regulating hormones. To further understand the influence of those hormones with SCs function and obesity, we hypothesize that human SCs express obesity‐related genes (ORG; MC4R, GNPDA2, TMEM18, and FTO) and that they respond to energy homeostasis regulating hormones (leptin, ghrelin, and glucagon‐like protein 1 [GLP‐1]) stimuli. To test our hypothesis, SCs were cultured with increasing doses of leptin (0, 5, 25, or 50 ng/ml, for 24 h), ghrelin (0, 20, 100, and 500 pM, for 24 h), and GLP‐1 (10, 1000, or 1 × 105 pM, for 6 h). The presence and abundance of ORG transcripts and proteins in SCs were accessed by polymerase chain reaction techniques, Western blot analysis, and immunofluorescence staining. Our results show that human SCs express MC4R, GNPDA2, TMEM18, and FTO in specific cellular locations. MC4R and FTO expression in human SCs was not responsive to the treatments. However, GNPDA2 and TMEM18 expression increased after exposure to the highest concentration of leptin and ghrelin, respectively. We highlight for the first time that human SCs express ORG and that these are responsive to energy homeostasis hormonal stimuli. GNPDA2 and TMEM18 expression respond in opposite directions according to overall energy status, mediated by energy homeostasis regulating hormones. Leptin and ghrelin control of ORG expression by human SCs can be associated with overweight‐related infertility and subfertility in males.

A cafeína é um componente comum do café, chá, bebidas energéticas, produtos que contenham cacau o... more A cafeína é um componente comum do café, chá, bebidas energéticas, produtos que contenham cacau ou chocolate e até mesmo de vários medicamentos. O consumo excessivo de cafeína tem sido associado a diversos problemas de foro reprodutivo. Além disso, foi demonstrado que este composto tem uma ação moduladora no metabolismo celular. Isto levou-nos a colocar a hipótese de a cafeína poder alterar o metabolismo das células de Sertoli humanas (hSCs), as quais são essenciais para a espermatogénese e para a fertilidade masculina. Para verificar esta hipótese, as hSCs foram cultivadas na presença de cafeína (5, 50 e 500 μM) e o seu perfil glicolítico foi avaliado através do estudo do consumo de glucose e da produção de lactato e alanina. Os níveis de expressão proteica dos transportadores de glucose (GLUT1 e GLUT3), fosfofrutoquinase 1 (PFK1), lactato desidrogenase (LDH) e transportador de monocarboxilatos 4 (MCT4) foram também determinados, assim como a atividade da enzima LDH. Para além diss...

As células de Sertoli (SCs) formam a barreira hematotesticular (BHT), controlando o microambiente... more As células de Sertoli (SCs) formam a barreira hematotesticular (BHT), controlando o microambiente onde a espermatogénese ocorre. O regulador de condutância transmembranar de fibrose cística (CFTR) tem um papel preponderante na fertilidade masculina, pois indivíduos com mutações no gene CFTR são normalmente sub-férteis ou inférteis. Para além de ser responsável pelo transporte de Cl-/HCO3-, o CFTR pode controlar o movimento de fluidos, regulando sistemas de transporte de água (Aquaporinas). [...]

A pioglitazona é um potente agonista sintético dos recetores ativados por proliferadores de perox... more A pioglitazona é um potente agonista sintético dos recetores ativados por proliferadores de peroxissoma gama utilizado para tratar a Diabetes Mellitus tipo 2 (DMT2). Outros benefícios para a utilização da pioglitazona têm sido reportados mas os seus efeitos na reprodução masculina permanecem desconhecidos. Além da pioglitazona, a metformina é uma biguanida usada como primeira linha no tratamento da DMT2. Ambos são utilizados na prática clínica como terapia combinada. [...]

Animals, 2022

Cryopreservation is globally used as a method for long-term preservation, although freeze-thawing... more Cryopreservation is globally used as a method for long-term preservation, although freeze-thawing procedures may strongly impair the gamete function. The correct cryopreservation procedure is characterized by the balance between freezing rate and cryoprotective agents (CPAs), which minimizes cellular dehydration and intracellular ice formation. For this purpose, osmoregulation is a central process in cryopreservation. During cryopreservation, water and small solutes, including penetrating cryoprotective agents, cross the plasma membrane. Aquaporins (AQPs) constitute a family of channel proteins responsible for the transport of water, small solutes, and certain gases across biological membranes. Thirteen homologs of AQPs (AQP0-12) have been described. AQPs are widely distributed throughout the male and female reproductive systems, including the sperm and oocyte membrane. The composition of the male and female gamete membrane is of special interest for assisted reproductive techniques...

The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement ... more The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement of several mechanisms, among which is included the transmembranous movement of H+ ions. Na+-H+ exchangers (SLC9, solute carrier 9 family members) are among the membrane transporters known to participate in intracellular and extracellular pH regulation but also have important roles in salt and water absorption across epithelia and in the regulation of cell volume. The presence of several Na+-H+ exchangers has been reported in the male reproductive tract. Their involvement in the processes that ensure the correct pursuance of the spermatogenetic event and spermatozoa maturation has been suggested. Indeed, the formation of mature spermatozoa is highly dependent on the maintenance of adequate ductal luminal milieu pH and ionic balance. Perturbations in these processes result in reduced male reproductive potential and consequently male subfertility and/or infertility. Thus, it is imperative t...

The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement ... more The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement of several mechanisms, among which is included the transmembranar movement of H + ions. Na + -H + exchangers (SLC9, solute carrier 9 family members) are amongst the membrane transporters known to participate in intracellular and extracellular pH regulation, but also have important roles on salt and water absorption across epithelia and on regulation of cell volume. The presence of several Na + -H + exchangers has been reported in the male reproductive tract. Their involvement in the processes that assure the correct pursuance of the spermatogenetic event and spermatozoa maturation has been suggested. Indeed, the formation of mature spermatozoa is highly dependent on the maintenance of adequate ductal luminal milieu pH and ionic balance. Perturbations in these processes result in reduced male reproductive potential and consequently male subfertility and/or infertility. Thus, it is imperat...

Introduction: Metabolic diseases are related with severe fertility problems, partly due to increa... more Introduction: Metabolic diseases are related with severe fertility problems, partly due to increased aromatization of androgens to estrogens. Elevated levels of 17β-Estradiol (E2) are known to cause alterations on normal development of germ cells, compromising spermatogenesis. Spermatogenesis is dependent on Sertoli cells (SCs) function, since these cells ensure an adequate environment inside the seminiferous tubule. Objective: To determine the impact of elevated levels of E2 on aquaglyceroporins (AQPs) expression and glycerol permeability in mouse SCs (mSCs, TM4 cell line). Material and Methods: The expression of AQP3, AQP7, AQP9, and AQP11 were identified by RT-PCR and immunofluorescence techniques. Then, the expression was evaluated by qRT-PCR. Glycerol permeability was evaluated by stopped flow light-scattering. Results: We were able to identify for the first time the expression of AQP3, AQP9 and AQP11 in mouse testis and mSCs. AQP9 was about six times more expressed than AQP3 a...

Free Radical Biology and Medicine, 2018

Tea (Camellia sinensis L.) is one of the most consumed beverages worldwide, not only due to its p... more Tea (Camellia sinensis L.) is one of the most consumed beverages worldwide, not only due to its pleasant organoleptic properties, but also to its antioxidant effects. The amino acid L-theanine, which is almost exclusively found in tea leaves, has demonstrated a protective role against oxidative damages in certain cell types. We hypothesized that L-theanine could maintain the in-vitro redox homeostasis of human Sertoli cells (hSCs). The proper functioning of these cells is essential for a successful sperm production. So, we evaluated the effect of L-theanine (50 μM) on the metabolism, mitochondrial functionality, and oxidative damages in hSCs. The exposure of hSCs to L-theanine resulted in an increased hSCs proliferation and a subsequent increase in glucose metabolization through glycolysis. In response to this metabolic adaptation, there was an increase in mitochondrial membrane potential, which could result in a redox imbalance. However, no alterations were observed in protein carb...

The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement ... more The maintenance of pH homeostasis in the male reproductive tract is kept through the involvement of several mechanisms, among which is included the transmembranous movement of H ions. Na-H exchangers (SLC9, solute carrier 9 family members) are among the membrane transporters known to participate in intracellular and extracellular pH regulation but also have important roles in salt and water absorption across epithelia and in the regulation of cell volume. The presence of several Na-H exchangers has been reported in the male reproductive tract. Their involvement in the processes that ensure the correct pursuance of the spermatogenetic event and spermatozoa maturation has been suggested. Indeed, the formation of mature spermatozoa is highly dependent on the maintenance of adequate ductal luminal milieu pH and ionic balance. Perturbations in these processes result in reduced male reproductive potential and consequently male subfertility and/or infertility. Thus, it is imperative to und...

Reproductive BioMedicine Online, 2020

All data generated and analysed during the study are included in this published article. AUTHOR C... more All data generated and analysed during the study are included in this published article. AUTHOR CONTRIBUTIONS AR was responsible for experimental procedures, data analysis, critical discussion, manuscript draft and critical approval of the final article. CF assisted in the determination of spermiogram characteristics and critical approval of the final article. RB, MGA and PFO assisted in the determination of oxidative stress and metabolism and critical approval of the final article. PV was responsible for sperm sample preparation at the IVF clinic and critical approval of the final article. AB was responsible for patient recruitment and IVF laboratory supervision and critical approval of the final article. MS was responsible for data analysis, critical discussion and final manuscript writing. RS was responsible for study conception and design, supervision of experimental procedures, data analysis, critical discussion, manuscript writing and critical approval of the final article.

International Transactions in Operational Research, 2020

In this article, we address the family traveling salesman problem (FTSP), an NP-hard problem that... more In this article, we address the family traveling salesman problem (FTSP), an NP-hard problem that may be seen as a generalization of the traveling salesman problem. In the FTSP, the set of cities is partitioned into several families and one wants to find the minimum cost route that visits a given number of cities in each family. We propose two metaheuristics, a population-based method and a local search method, and a hybrid algorithm, which combines a branch-and-cut algorithm with a local search procedure. All the proposed methods improve the best known upper bounds from the literature. The local search method and the hybrid algorithm improve the best known upper bounds for all the benchmark instances with unknown optimal value, while the population-based method improves the best known upper bounds for all instances, except two. Furthermore, we developed an instance generator to create additional test instances with different visit patterns. These newly generated instances were considered in the computational experiment and, thus, we provide optimal values or upper bounds for each instance. Additionally, we created a website dedicated to the FTSP, where this information is made available to the scientific community (http://familytsp.rd.ciencias. ulisboa.pt/).

International Transactions in Operational Research, 2016

In this paper we address the traveling purchaser problem, an NP-hard problem that generalizes the... more In this paper we address the traveling purchaser problem, an NP-hard problem that generalizes the traveling salesman problem. We present several metaheuristics that combine genetic algorithms and local search. The genetic algorithms are induced by different hierarchic orderings of the decision making regarding the route and the acquisition of the items. Computational experiments were carried out with benchmark instances and the results show that the proposed metaheuristics are a suitable tool to solve high-dimensioned instances for which the exact methods do not provide solutions within a reasonable CPU time. For several instances, best new upper bounds for the optimum value of the objective function were obtained.