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Sexual motivation is an abstract concept referring to the mechanisms determining the responsivity to sexually relevant stimuli. This responsivity determines the likelihood of producing a sexual response and the intensity of that response. Both responsivity to stimuli and the likelihood of making a response as well as the intensity of response are characteristics of an individual. Therefore, we need to assume that the concept of sexual motivation materializes in physiological mechanisms within the individual. The aim of the present communication is to analyze the requisites for the endeavor to materialize sexual motivation. The first requisite is to provide an operational definition, making the concept quantifiable. We show that parameters of copulatory behavior are inappropriate. We argue that the intensity of sexual approach behaviors provides the best estimate of sexual motivation in non-human animals, whereas the magnitude of genital responses is an exquisite indicator of human sexual motivation. Having assured how to quantify sexual motivation, we can then proceed to the search for physiological or neurobiological underpinnings. In fact, sexual motivation only manifests itself in animals exposed to appropriate amounts of gonadal hormones. In female rats, the estrogen receptor α in the ventrolateral part of the ventromedial nucleus of the hypothalamus is necessary for the expression of sexual approach behaviors. In male rats, androgen receptors within the medial preoptic area are crucial. Thus, in rats sexual motivation can be localized to specific brain structures, and even to specific cells within these structures. In humans, it is not even known if sexual motivation is materialized in the brain or in peripheral structures. Substantial efforts have been made to determine the relationship between the activity of neurotransmitters and the intensity of sexual motivation, particularly in rodents. The results of this effort have been meager. Likewise, efforts of finding drugs to stimulate sexual motivation, particularly in women complaining of low sexual desire, have produced dismal results. In sum, it appears that the abstract concept of sexual motivation can be reliably quantified, and the neurobiological bases can be described in non-human animals. In humans, objective quantification is feasible, but the neurobiological substrate remains enigmatic.

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We describe a gland in the arthrodial membrane of the coxa-trochanter articulation in the fourth pair of legs in the Neotropical harvester Mischonyx squalidus Bertkau, 1880. Externally the glandular area has a rough appearance with pores on its surface, with folds of the arthrodial membrane. Internally, its secretory cells have spherical secretory vesicles, smooth endoplasmic reticulum, mitochondria and ducts that exit from the cells and cross the arthrodial membrane. Histochemical tests indicate the presence of proteins and neutral glycoproteins. The function of the gland might be to produce lubricating products that allow better movement of the coxa-trochanter region.

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We describe a gland in the arthrodial membrane of the coxa-trochanter articulation in the fourth pair of legs in the Neotropical harvester Mischonyx squalidus Bertkau, 1880. Externally the glandular area has a rough appearance with pores on its surface, with folds of the arthrodial membrane. Internally, its secretory cells have spherical secretory vesicles, smooth endoplasmic reticulum, mitochondria and ducts that exit from the cells and cross the arthrodial membrane. Histochemical tests indicate the presence of proteins and neutral glycoproteins. The function of the gland might be to produce lubricating products that allow better movement of the coxa-trochanter region.

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Lubricants are materials able to reduce friction and/or wear of any type of moving surfaces facilitating smooth operations, maintaining reliable machine functions, and reducing risks of failures while contributing to energy savings. At present, most worldwide used lubricants are derived from crude oil. However, production, usage and disposal of these lubricants have significant impact on environment and health. Hence, there is a growing pressure to reduce demand of this sort of lubricants, which has fostered development and use of green lubricants, as vegetable oil-based lubricants (biolubricants). Despite the ecological benefits of producing/using biolubricants, availability of the required raw materials and agricultural land to create a reliable chain supply is still far from being established. Recently, biomass from some microalgae species has attracted attention due to their capacity to produce high-value lipids/oils for potential lubricants production. Thus, this multidisciplinary work reviews the main chemical-physical characteristics of lubricants and the main attempts and progress on microalgae biomass production for developing oils with pertinent lubricating properties. In addition, potential microalgae strains and chemical modifications to their oils to produce lubricants for different industrial applications are identified. Finally, a guide for microalgae oil selection based on its chemical composition for specific lubricant applications is provided.

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Abstract Introduction: The climacteric is one of the transition periods in the life cycle of women between the reproductive and non-reproductive phase, and it is characterized by various metabolic, psychological and social changes, either by psychic disorders or sexual dysfunctions promoting changes in quality of life. Objective: To analyze the repercussions of electrical stimulation on quality of life, lubrication and myoelectric activity of pelvic floor muscles in postmenopausal women. Methods: This was a pilot study in which the sample consisted of ten menopausal volunteers aged 48-60 years. We used the Female Sexual Function Index questionnaire to determine the improvement in lubrication and the WHOQOL-BREF questionnaire to assess quality of life. The pelvic floor muscles were evaluated by electromyography with an intracavitary electrode. The protocol used was: phasic contraction evaluated by three contractions of two seconds and six of rest; three tonic contractions for ten seconds with ten-second rest; and endurance for thirty seconds. The intervention was performed by another researcher, through circulatory stimulation with the Dualpex 961 Quark®. Results: Electromyography after circulatory stimulation showed statistically significant results with an increase in Fast Fourier Transform in tonic and phasic contractions, obtaining a positive effect on the perception and awareness of contractions due to increased blood flow. Also, there was improvement in lubrication and quality of life in all areas. Conclusion: Circulatory stimulation had repercussions on pelvic floor muscles in menopausal women in both muscle physiology and lubrication, with an influence on the quality of life of volunteers.

Resumo Introdução: O climatério constitui um dos períodos de transição no ciclo vital da mulher entre a fase reprodutiva e a não reprodutiva, caracterizado por várias alterações metabólicas e psicológicas, seja por distúrbios psíquicos ou disfunções sexuais, promovendo alterações na qualidade de vida. Objetivo: Analisar as repercussões da eletroestimulação na qualidade de vida, lubrificação e atividade mioelétrica dos músculos do assoalho pélvico em mulheres menopausadas. Métodos: Trata-se de um estudo piloto no qual a amostra foi composta por dez voluntárias em menopausa com idade entre 48 e 60 anos. Para avaliar a melhora da lubrificação foi utilizado o questionário Female Sexual Function Index. Quanto à qualidade de vida, utilizou-se o questionário WHOQOL-bref. Já para a avaliação dos músculos do assoalho pélvico, utilizou-se a eletromiografia com eletrodo intracavitário. O protocolo utilizado foi: contração fásica avaliada por três contrações de dois segundos e seis de repouso; três contrações tônicas sustentadas por dez segundos com repouso de dez segundos; endurance durante trinta segundos. A intervenção foi realizada por outra pesquisadora, através de estimulação circulatória com o aparelho Dualpex 961 Quark®. Resultados: A eletromiografia pós-estimulação circulatória obteve resultados significativos, com aumento na Fast Fourier Transform nas contrações tônicas e fásicas, obtendo efeito positivo na percepção e conscientização das contrações devido ao aumento do fluxo sanguíneo. Houve, também, melhora na lubrificação e na qualidade de vida em todos os domínios. Conclusão: A estimulação circulatória apresentou repercussões nos músculos do assoalho pélvico em mulheres menopausadas tanto na fisiologia muscular quanto na lubrificação, influenciando a qualidade de vida das voluntárias.

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This paper presents a study of the Ti-6Al-4V alloy milling under different lubrication conditions, using the minimum quantity lubrication approach. The chosen material is widely used in the industry due to its properties, although they present difficulties in terms of their machinability. A minimum quantity lubrication (MQL) prototype valve was built for this purpose, and machining followed a previously defined experimental design with three lubrication strategies. Speed, feed rate, and the depth of cut were considered as independent variables. As design-dependent variables, cutting forces, torque, and roughness were considered. The desirability optimization function was used in order to obtain the best input data indications, in order to minimize cutting and roughness efforts. Supervised artificial neural networks of the multilayer perceptron type were created and tested, and their responses were compared statistically to the results of the factorial design. It was noted that the variables that most influenced the machining-dependent variables were the feed rate and the depth of cut. A lower roughness value was achieved with MQL only with the use of cutting fluid with graphite. Statistical analysis demonstrated that artificial neural network and the experimental design predict similar results.

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La osteoartritis se considera una de las principales causas de discapacidad funcional. Es una enfermedad crónica y degenerativa que presenta un pico de incidencia en personas mayores de 60 años. El propósito de este trabajo es mostrar los avances en la terapia de pacientes con osteoartritis basada en ácido hialurónico para pacientes con osteoartritis. El ácido hialurónico posee funciones en la articulación que abarcan la lubricación, servir como relleno de espacio para permitir que la articulación permanezca abierta y la regulación de actividades celulares como la unión de proteínas. Cada vez hay más pruebas de que, dentro del espectro de derivados disponibles del ácido hialurónico, la eficacia de los productos de ácido hialurónico con un alto peso molecular es superior a la eficacia de los derivados con un bajo peso molecular. Aprovechando el control espacial de ciertos tipos de hidrogeles de ácido hialurónico, se están desarrollando sistemas de microdispositivos que pueden encapsular células madre embrionarias viables y luego recuperarlas mediante interrupción mecánica. Estas células madre podrían usarse para el tratamiento de enfermedades como la osteoartritis. El ácido hialurónico es un fármaco que puede para ayudar a reducir los efectos secundarios de la osteoartritis(AU)

Osteoarthritis is considered one of the main causes of functional disability. Osteoarthritis conceptualized as a chronic and degenerative disease that presents a peak incidence in people older than 60 years. To show advances in hyaluronic acid-based therapy for patients with osteoarthritis. Hyaluronic acid has functions in the joint that include lubrication, which serves as a filling of space to allow the joint to remain open and the regulation of cellular activities such as protein binding. Hyaluronic acid is a potential drug to help reduce the side effects of osteoarthritis(AU)

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Abstract Objective: This study investigated the effect of the condition of lubrication on the friction between brackets and NiTi archwires of different rounded cross-sections. Methods: Brackets (Roth, GAC) were affixed to a device connected to a universal testing machine into which segments of archwire were placed (NiTi, Nitinol, GAC) with cross-sections of 0.012-in, 0.016-in and 0.020-in. Once the wire was in the bracket slot, the following lubricants were applied: human saliva (HS: positive control), distilled water (DI), mucin-based (MUC) or carboxymethylcellulose-based (CMC) artificial saliva. In the negative control group, no lubricant was used. The combination between the wire cross-sections and the lubrication condition generated 15 groups with 15 samples each. Data were submitted to two-way analysis of variance and Tukey's test. Results: There was no significant interaction between the wire cross-section and the condition of lubrication (p= 0.901). Irrespective of whether lubricants were used or not, there was a significant increase in friction with an increase in the cross-section of the wire (p< 0.001). For any wire, the group tested in the presence of MUC was not different from that in which HS was applied. On the other hand, when the application of lubricants was suppressed, significantly higher friction values were observed. The CMC group and the DI group demonstrated intermediate behavior. Conclusions: Friction increased with the increase of the cross-section of the NiTi archwire, but regardless of the archwire, friction with MUC artificial saliva was similar to that of HS and lower than in dry conditions.

Resumo Objetivo: este estudo investigou o efeito das condições de lubrificação no atrito entre braquetes e fios de NiTi de diferentes secções transversais. Métodos: os braquetes (Roth, GAC) foram fixados a um dispositivo conectado a uma máquina de ensaio universal, que recebeu segmentos de fio de NiTi (Nitinol, GAC) com secções de 0,012"; 0,016" ou 0,020". Após o fio ter sido instalado no slot do braquete, aplicou-se um dos seguintes lubrificantes: saliva humana (SH: controle positivo), água destilada (AD) ou saliva artificial à base de mucina (MUC) ou de carboximetilcelulose (CMC). No grupo controle negativo, nenhum lubrificante foi utilizado. As combinações entre as secções dos fios e as condições de lubrificação geraram 15 grupos, com 15 amostras cada. Os dados foram submetidos à análise de variância a dois critérios e ao teste de Tukey. Resultados: não houve interação significativa entre a secção do fio e a condição de lubrificação (p = 0,901). Independentemente de ter sido utilizado ou não lubrificante, observou-se elevação significativa do atrito com o aumento da secção transversal do fio (p < 0,001). Para qualquer um dos fios, o grupo testado na presença de MUC não diferiu daquele em que se aplicou SH. Por outro lado, quando suprimiu-se os lubrificantes, constatou-se atrito significativamente mais elevado. Os grupos CMC e AD demonstraram comportamento intermediário. Conclusões: o atrito se elevou com o aumento da secção transversal dos fios de NiTi, mas a despeito do fio, o atrito com a saliva à base de MUC foi similar àquele com a SH e menor do que sob condição a seco.

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Friction is the natural response of all tribosystems. In a total knee replacement (TKR) prosthetic device, its measurement is hindered by the complex geometry of its integrating parts and that of the testing simulation rig operating under the ISO 14243-3:2014 standard. To develop prediction models of the coefficient of friction (COF) between AISI 316L steel and ultra-high molecular weight polyethylene (UHMWPE) lubricated with fetal bovine serum dilutions, the arthrokinematics and loading conditions prescribed by the ISO 142433: 2014 standard were translated to a simpler geometrical setup, via Hertz contact theory. Tribological testing proceeded by loading a stainless steel AISI 316L ball against the surface of a UHMWPE disk, with the test fluid at 37 °C. The method has been applied to study the behavior of the COF during a whole walking cycle. On the other hand, the role of protein aggregation phenomena as a lubrication mechanism has been extensively studied in hip joint replacements but little explored for the operating conditions of a TKR. Lubricant testing fluids were prepared with fetal bovine serum (FBS) dilutions having protein mass concentrations of 5, 10, 20 and 36 g/L. The results were contrasted against deionized, sterilized water. The results indicate that even at protein concentration as low as 5 g/L, protein aggregation phenomena play an important role in the lubrication of the metal-on-polymer tribopair. The regression models of the COF developed herein are available for numerical simulations of the tribological behavior of the aforementioned tribosystem. In this case, surface stress rather than film thickness should be considered.

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BACKGROUND: The different forms of lubrication are among the most simple, accessible, and economic techniques that have been implemented for improving the diagnostic performance of colonoscopy. AIM: To determine whether the use of oil improved the number of complete colonoscopies, facilitated the procedure, reduced pain, or improved the study's diagnostic performance, compared with the conventional lubrication technique. PATIENTS AND METHODS: One hundred and seventy-five patients referred for colonoscopy were alternately allocated to receive treatment with the standard lubrication method with chlorhexidine gel (group 1) or lubrication with corn oil administered through the working channel (group II). The number of complete colonoscopies, the length of time needed to reach the cecum, the degree of difficulty estimated by the endoscopist and the assistant, the level of pain at the end of the study estimated by the patient, and the endoscopic findings were all determined. RESULTS: Eighty-eight patients made up group I and 87 made up group II. No statistically significant differences were found between the two groups in relation to general characteristics, the number of complete colonoscopies (93 vs. 97%, respectively), the time needed to reach the cecum (8:00 vs. 8:41min, respectively), the level of pain at the end of the study, or the detection of polyps. The degree of difficulty was slightly lower in group II, but with no statistical significance. CONCLUSIONS: Lubrication with oil during colonoscopy did not improve the number of complete colonoscopies, did not facilitate the study, nor did it reduce pain or increase the diagnostic performance of the study, when compared with the conventional technique.

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OBJECTIVE: To evaluate the effect of different lubricants on friction between orthodontic brackets and archwires. MATERIALS AND METHODS: Active (Quick, Forestadent) and passive (Damon 3MX, Ormco) self-ligating brackets underwent friction tests in the presence of mucin- and carboxymethylcellulose (CMC)-based artificial saliva, distilled water, and whole human saliva (positive control). Dry friction (no lubricant) was used as the negative control. Bracket/wire samples (0.014 × 0.025 inch, CuNiTi, SDS Ormco) underwent friction tests eight times in a universal testing machine. RESULTS: Two-way analysis of variance showed no significant interaction between bracket type and lubricant (P  =  .324). Friction force obtained with passive self-ligating brackets was lower than that for active brackets (P < .001). Friction observed in the presence of artificial saliva did not differ from that generated under lubrication with natural human saliva, as shown by Tukey test. Higher friction forces were found with the use of distilled water or when the test was performed under dry condition (ie, with no lubricant). CONCLUSION: Lubrication plays a role in friction forces between self-ligating brackets and CuNiTi wires, with mucin- and CMC-based artificial saliva providing a reliable alternative to human natural saliva.

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La literatura revisada para el presente artículo requirió el análisis de aspectos reológicos aplicables a la saliva humana y los sustitutos salivales. La saliva cuenta entre sus componentes glicoproteínas tipo mucina, las características bioquímicas de dichas glicoproteínas le confieren a la saliva sus propiedades reológicas, tales como viscosidad, lubricación y elasticidad. Las moléculas de mucina en solución presentan asociación y gelificación; la dinámica de estos procesos se ha estudiado por diversas técnicas e instrumentos. La hidratación de las mucinas es necesaria para que estas se gelifiquen, y le confieran a la saliva (o sus soluciones), viscosidad, lubricación y elasticidad, los mecanismos para que esto ocurra se apoyan en un Equilibrio de Donnan, sin embargo, en el fluido salival humano, la concentración fisiológica de mucina es tal que no permite la observación de gelificación. No obstante, a concentraciones mayores sí podría ser observada. Se han realizado estudios para el desarrollo de sustitutos salivales con compuestos de naturaleza glucídica y con mucinas extraídas de diversos tejidos animales, individualmente y en mezcla, con el objeto de aliviar la sintomatología de patologías que disminuyen el flujo salival, estos estudios han demostrado que la mucina extraída de glándulas submandibulares de bovino es la que mejor se adapta a los parámetros reológicamente deseables para un sustituto salival.

In this review it is considered the rheological aspects of human saliva and salivary substitutes. Saliva has mucin like glycoproteins, which confer saliva its rheological properties, such as viscosity, lubrication and elasticity. Mucin molecules have gel forming properties; the dynamic of this process have been widely discussed. Mucin hydration is necessary for gelification and lubrication, mucin hydration confers saliva, viscosity, elasticity and lubrication properties, the hydration mechanism is based on a Donnan Equilibrium. The physiological concentration of mucins in human saliva is not sufficiently high to show gelification, however, this property can be displayed at higher concentrations. Sugar derivatives and animal mucins have been studied, either isolated or at mixtures for the development of salivary substitutes, these studies showed that mucin extracted from bovine submaxillary glands is best suited to accomplish the desirable parameters for a salivary substitute.