Antimicrobial activity of Er, Cr: YSGG and Ultrasonic on E. faecalisbiofilm in the mesial root canal systems of lower molars / Atividade antimicrobiana de Er, Cr: YSGG e Ultrassônico no biofilme de E. faecalis nos sistemas de canais radiculares mesiais de molares inferiores

The internal topography of the root canal is complex, especially for the permanent molar's mesial root. In response to such issues, improved irrigation techniques have been created, which use laser pulses to agitate fluids and improve microbial deposit removal. Objective: To assess the effectiveness of the Er,Cr:YSGG laser with a wavelength of 2,780 nm via photon-induced photoacoustic streaming (PIPS) protocol which agitated of 2% chlorohexidine (CHX) in removing mature Enterococcus faecalis (E. faecalis) biofilm in root canal systems of lower molars. Material and Methods: The mesial roots of lower first and second molars were separated and inoculated with E. faecalis bacterial suspension for 30 days. The roots were irrigated with CHX, some of them were agitated with a passive ultrasonic device (PUI), while the other roots were agitated by an Er,Cr:YSGG laser in PIPS at 60 µs/pulse, 5 Hz, (0.25, 0.5, 0.75, and 1) W. An atomic force microscope (AFM) was used as a new method to get the results in the isthmus area; the obtained results from each group were compared with each other. Results: Based on the AFM and SEM analyses, laser and ultrasonic activation groups showed higher antimicrobial efficacy than the conventional syringe irrigation group (P<0.05). Conclusion: Based on the investigation's findings, the activation of 2% CHX solution by Er,Cr:YSGG laser in PIPS and PUI offers better mature bacterial biofilm removal in the mesial root of lower human molars than the same irrigant with the SI technique (AU)

A topografia interna do canal radicular é complexa, especialmente para a raiz mesial do molar permanente. Em resposta a esses problemas, foram criadas técnicas aprimoradas de irrigação, que utilizam pulsos de laser para agitar fluidos e melhorar a remoção de depósitos microbianos. Objetivo: Avaliar a eficácia do laser Er,Cr:YSGG com comprimento de onda de 2.780 nm via protocolo de streaming fotoacústico induzido por fótons (PIPS) que agitou clorohexidina a 2% (CHX) na remoção de Enterococcus faecalis maduro (E. faecalis) biofilme em sistemas de canais radiculares de molares inferiores. Material e Métodos: As raízes mesiais de 28 primeiros e segundos molares inferiores foram separadas e inoculadas com suspensão bacteriana de E. faecalis por 30 dias. As raízes foram irrigadas com CHX, sendo algumas delas agitadas com aparelho ultrassônico passivo (PUI), enquanto as demais raízes foram agitadas com laser Er,Cr:YSGG em PIPS a 60 µs/pulso, 5 Hz (0,25, 0,5, 0,75 e 1) W. Um microscópio de força atômica (AFM) foi utilizado como um novo método para obter os resultados na área do istmo; os resultados obtidos de cada grupo foram comparados entre si. Resultados: Com base nas análises de AFM e SEM, os grupos de ativação por laser e ultrassom apresentaram maior eficácia antimicrobiana do que o grupo de irrigação com seringa convencional (P<0.05). Conclusão: Com base nos achados da investigação, a ativação da solução de CHX a 2% pelo laser Er,Cr:YSGG em PIPS a (60 µs/pulso, 5 Hz, 0,75 W) oferece melhor remoção de biofilme (AU)

Assessment the retentive force and XRD analysis on the recycling esthetic thermoplastic acetal clasps / Avaliação da força de retenção e análise de DRX dos grampos de resina estética termoplástica acetal reciclada

Objective: To reduce environmental biohazards, technicians should be educated with safe biological waste disposal procedures and dental material recycling. The present study assesses the retentive force, deformation test and XRD analysis of re-injection acetal resin clasps. Material and Methods: specimens were prepared for clasp retention test injection according to the manufacture's instruction for acetal resin. The first group represent control group with (100% New) and other five groups as experimental groups (group II (25% old +75% new), group III (50% old + 50%) new, and group IV (75% old + 25% new) with different percentages between new acetal materials and old acetal materials, while two last groups with several times (group V (100% old) and group VI (re-injection two times)) only used old acetal materials. The X-ray diffraction (XRD) device used to give structural information for the materials to be tested. The study data were analyzed via One-way ANOVA (LSD) at a significant P-value of (p≤0.05) and a confidence level of 95%. Results: After comparing the results, a significant improvement in the retentive force of acetal clasp specimens after re-injection two times there was found high mean value in group re-injection two times and lower mean value recorded in control group. In XRD patterns of there was no diffraction peak refers to crystal structure of acetal resin. Conclusion: the present study findings concluded that the recycling of acetal resin enhanced the retentive force of acetal clasp and not affected on the crystal structures of material(AU)

Objetivo: Para reduzir os riscos biológicos ambientais, os técnicos devem ser educados com procedimentos seguros de eliminação de resíduos biológicos e reciclagem de material dentário. O presente estudo avalia a força de retenção, teste de deformação e análise de DRX de grampos de resina acetal reinjetada. Material e Métodos: as amostras foram preparadas para o teste de retenção dos grampos e a injeção realizada de acordo com as instruções do fabricante para resina de acetal. O primeiro grupo representa o grupo controle com (100% novo) e os outros cinco grupos como grupos experimentais (grupo II (25% antigo + 75% novo), grupo III (50% antigo + 50% novo) e grupo IV (75% antigo + 25% novo) com porcentagens diferentes entre materiais de acetal novos e antigos, enquanto os dois últimos grupos (grupo V (100% antigo) e grupo VI (reinjeção duas vezes)) utilizaram apenas materiais de acetal antigos. O dispositivo de difração de raios X (DRX) foi utilizado para fornecer informações estruturais dos materiais a testados. Os dados do estudo foram analisados por ANOVA um fator (LSD) com um valor P significativo de (p≤0,05) e um nível de confiança de 95%. Resultados: Após a comparação dos resultados, foi encontrada uma melhora significativa na força de retenção das amostras de grampo de acetal após duas reinjeções, além disso, foi registrado um maior valor médio no grupo reinjeção duas vezes e menor valor médio no grupo controle. Nos padrões de DRX não houve pico de difração referente à estrutura cristalina da resina acetal. Conclusão: os resultados do presente estudo concluíram que a reciclagem da resina de acetal aumentou a força retentiva do grampo e não afetou as estruturas cristalinas do material(AU)

Exploring Scientific Connotation of "Fried Charcoal Survivability" of Lonicerae Japonicae Flos Based on Color-composition Correlation / 中国实验方剂学杂志

ObjectiveTo explore the scientific connotation of fried charcoal survivability of Lonicerae Japonicae Flos（LJF） by analyzing the correlation between the color change and the intrinsic components during the processing of LJF Carbonisata（LJFC）， and taking pH， charcoal adsorption and microscopic characteristics as indexes. MethodLJFC samples with different degrees of processing were prepared according to the stir-frying time of 0.0， 1.5， 3.0， 4.5， 6.0， 7.5， 9.0， 10.5 min（numbered S1-S8）， and the contents of gallic acid， chlorogenic acid， cryptochlorogenic acid， rutin， luteoloside， isochlorogenic acid A and isochlorogenic acid C were determined by high performance liquid chromatography（HPLC）， and the L*（brightness）， a*（red-greenness） and b*（yellow-blueness） of LJFC samples with different degrees of processing were determined by spectrophotometer， and the correlation analysis and principal component analysis（PCA） between the contents of seven representative components and the color of the samples were carried out by SPSS 26. 0 and SIMCA-P 14.1. Then pH， adsorption force and characteristic structure of different samples of LJFC were detected and the processing pattern of LJFC was analyzed. ResultThe results of quantitative analysis revealed that the contents of luteoloside， rutin， chlorogenic acid and isochlorogenic acid A gradually decreased， and the contents of cryptochlorogenic acid， isochlorogenic acid C and gallic acid firstly increased and then decreased. The L* and b* of the sample powders decreased， and a* showed a trend of increasing and then decreasing. The L* and b* were positively correlated with the contents of chlorogenic acid， rutin， luteoloside， isochlorogenic acid A， b* was positively correlated with the content of gallic acid， and a* was positively correlated with the contents of cryptochlorogenic acid and isochlorogenic acid C. PCA revealed that samples could be clearly divided into 3 groups， S1-S2 as one group， S3-S5 as one group， and S6-S8 as one group， with S3 having the highest score. The results of regression analysis showed that only isochlorogenic acid C could be used to predict the contents of components by colorimetric values combined with regression equations. Physicochemical analysis showed that pH of LJFC increased with the increase of degree of charcoal stir-frying， while adsorption force showed a tendency of increasing and then decreasing， with the highest adsorption force in the S5 sample， and the non-glandular hairs， calcium oxalate clusters and pollen grains had a varying degree of decreasing with the deepening of processing degree， and the microstructures of S6-S8 samples were obviously charred with pollen grains almost invisible. ConclusionThe changes in chemical composition and color characteristics of LJFC during the processing have certain correlations， combined with the changes in physicochemical properties， S5 sample is found to be the optimal processed products， which can provide a reference for the processing standardization and quality evaluation of LJFC， and enrich the scientific connotation of fried charcoal survivability of LJF.

Multiempleo en salud en provincia de Buenos Aires: estudio transversal de profesiones afectadas al cuidado de pacientes con COVID-19 / Multi-employment in health in the province of Buenos Aires: cross-sectional study of professions involved in COVID-19 patient care

RESUMEN INTRODUCCIÓN La pandemia de COVID-19 expuso el impacto del multiempleo en los servicios de salud. El objetivo de este estudio fue caracterizar el multiempleo en médicos y enfermeros que trabajaron en internación general y cuidados críticos durante la pandemia en la provincia de Buenos Aires. MÉTODOS Se realizó un estudio exploratorio, descriptivo y transversal. Los datos se recolectaron en el primer trimestre de 2021 con una encuesta estructurada anónima autoadministrada mediante muestreo no probabilístico en cadena. RESULTADOS El 96,3% de los médicos y el 68,1% de los enfermeros declararon estar multiempleados. La media de empleos fue 3,1 para médicos (entre 1 y 5) y 1,9 para enfermeros (entre 1 y 3). Los enfermeros declararon trabajos con mayor carga horaria, predominio del empleo público y contratación estable. Los médicos multiempleados manifestaron mayor diversidad en la forma de contratación. En ambas profesiones el multiempleo es motivado principalmente por razones de índole económica. DISCUSIÓN El multiempleo es difícil de medir mediante los registros oficiales. La proporción de multiempleo autorreportado en este estudio supera las cifras comunicadas por las estadísticas e informes oficiales. Aun así, las diferencias halladas entre médicos y enfermeros respecto al número de empleos son coincidentes con estudios previos. El problema del multiempleo requiere ser abordado desde la desprecarización del empleo, con mejoras en las condiciones económicas y de trabajo.

ABSTRACT INTRODUCTION The COVID-19 pandemic exposed the impact of multi-employment in health services. The objective of this study was to characterize multi-employment among physicians and nurses working in general hospitalization and critical care during the pandemic in the province of Buenos Aires. METHODS An exploratory, descriptive, cross-sectional study was conducted. Data were collected in the first quarter of 2021 with a structured anonymous self-administered survey using non-probabilistic chain sampling. RESULTS A total of 96.3% of physicians and 68.1% of nurses reported being multi-employed. The mean number of jobs was 3.1 for physicians (between 1 and 5) and 1.9 for nurses (between 1 and 3). Nurses reported having jobs with longer hours, mostly public and stable employment. Multi-employed physicians reported greater variety in the form of hiring. In both professions, multi-employment is mainly motivated by economic reasons. DISCUSSION Multi-employment is difficult to measure through official records. The proportion of self-reported multiemployment in this study exceeds the figures shown by official statistics and reports. The differences found between physicians and nurses regarding the number of jobs are still consistent with previous studies. The problem of multi-employment needs to be tackled by making employment less precarious, with improvements in economic and working conditions.

Effect of acupuncture on the molar bite force in women with chronic neck pain / Efecto de la acupuntura sobre la fuerza de mordida en mujeres con cervicalgia crónico

Objetive: To investigate the maximum molar bite force in women with chronic neck pain after treatment with acupuncture. Materials and Methods: Twenty-three women with chronic neck pain participated. Dynamometer was used to measure the right and left maximum molar bite force. Dong Bang acupuncture needles - 0.25 mm x 30 mm was inserted into the integumentary tissue. Treatment was 10 sessions, each 30 minutes long and twice a week. Results: The right (p = 0.01) and left (p = 0.004) molar bite force was assessed after treatment with acupuncture, and showed increased occlusal strength. Conclusions: This study suggests a functional improvement in the stomatognathic system in women with chronic cervical pain after treatment with acupuncture. However, it is important to note that further research is needed to fully elucidate the long-term effects and potential clinical implications of these findings in the field of pain management and rehabilitation.

Objetivo: Investigar la fuerza masticatoria máxima en mujeres con dolor crónico de cuello después del tratamiento con acupuntura. Materiales y Métodos: Participaron veintitrés mujeres con dolor crónico de cuello. Se utilizó un dinamómetro para medir la fuerza máxima de mordida del molar derecho e izquierdo. Agujas de acupuntura Dong Bang se insertaron 0,25 mm x 30 mm en el tejido tegumentario. El tratamiento fue de 10 sesiones, cada una de 30 minutos de duración, dos veces por semana. Resultados: Se observó la fuerza de mordida del molar derecho (p=0.01) e izquierdo (p=0.004) después del tratamiento con acupuntura, que mostró un aumento de la fuerza oclusal. Conclusión: Este estudio sugiere una mejora funcional en el sistema estomatognático en mujeres con dolor cervical crónico después del tratamiento con acupuntura. Sin embargo, es importante señalar que se necesita más investigación para dilucidar por completo los efectos a largo plazo y las posibles implicaciones clínicas de estos hallazgos en el campo del tratamiento y la rehabilitación del dolor.

Analysis on the application of medical force in Shenzhou manned spaceflight missions and enlightenment for medical service support with new regions and new types / 中华急诊医学杂志

Objective:To summarize the practice and experience of medical service support for Shenzhou manned spaceflight mission, and to explore the accurate medical service support strategy with new regions and new types.Methods:A systematic summary was made from the force command, action framework, technical support, and the practice and experience in the application of medical support force for Shenzhou manned flight mission were sorted out.. Furthermore, the key and difficult problems of the new domains with new types of military medical service support were analyzed, and the scheme and significance of establishing the accurate support mode of the new medical service support force were proposed.Results:The Shenzhou emergency rescue mission was an elite combat supported by a large platform. It was an important basis to realize accurate medical service support by the experience of utilizing the medical force of Shenzhou emergency rescue and the strengthening of war-building mode optimization.Conclusions:This paper systematically summarizes the experience and characteristics of medical force application in Shenzhou manned spaceflight missions, and provides new ideas and methods for future diversified and accurate s medical service support with new regions and new types.

A monitoring aid for movement disorder rehabilitation / 国际生物医学工程杂志

Objective:To design a motor impairment rehabilitation monitoring aid for the assessment of motor impairment in patients who do not have or have difficulty walking independently.Methods:An assistive device vehicle was designed, equipped with an accelerometer and a six-dimensional force sensor. The normal walking (NW) group and abnormal walking group were set up, in which the abnormal walking group included moderate abnormal walking (MA) group, moderate abnormal walking with the aid of the assistive vehicle (MA-V) group, severe abnormal walking (SA) group, and severe abnormal walking with the aid of the assistive vehicle (SA-V) group. In the MA-V group, the range of knee movement was adjusted from 0 to 30°, and in the SA group, the knee joint was completely unbending. The gait cycles, peak and mean acceleration values of the right and left legs were evaluated by accelerometers, and changes in the upper limb forces were assessed by six-dimensional force transducers.Results:For the moderate impairment group, the difference in gait cycle between the MA and MA-V groups was not statistically significant ( P>0.05), and the gait cycle in the MA-V group was slightly greater than that in the MA group. For the severe injury group, the gait cycle of the SA-V group was lower than that of the SA group, and the difference was statistically significant ( P<0.01). For all abnormal groups, the mean and peak acceleration of the left leg were greater than that of the right leg, and the difference between the peak acceleration of the left leg and that of the right leg was statistically significant ( P<0.05). In the abnormal walking pattern, the mean (absolute) value of the left hand force was greater than that of the right hand, especially in the Z-axis. The standard deviations of the combined forces on the left side for the NW, MA-V, and SA-V groups were 2.759, 8.297, and 13.118 N, respectively. The SA-V group had the highest dispersion in the force scatter plot, while the NW group had a better concentration. Conclusions:An assistive vehicle equipped with an accelerometer and a six-dimensional force sensor was designed to help physicians in the assessment and rehabilitation of motor disorders.

An Algorithm for Measuring Vertical Ground Reaction Force Based on Insole Sensors / 医用生物力学

Objective A practical and highly accurate algorithm for dynamic monitoring of plantar pressure was proposed, the magnitude of vertical ground reaction force (vGRF) during walking was measured by a capacitive insole sensor, and reliability of the prediction accuracy was verified. Methods Four healthy male subjects were require to wear capacitive insole sensors, and their fast walking and slow walking data were collected by Kistler three-dimensional (3D) force platform. The data collected by the capacitive insole sensors were pixelated, and then the processed data were fed into a residual neural network, ResNet18, to obtain high-precision vGRF. Results Compared with analysis of the data collected from Kister force platform, the normalized root mean square error (NRMSE) for fast walking and slow walking were 8.40% and 6.54%, respectively, and the Pearman correlation coefficient was larger than 0.96. Conclusions This study provides a novel algorithm for dynamic measurement of GRF in mobile scenarios, which can be used for estimation of complete GRF outside the laboratory without being constrained by the number and location of force plates. Potential application areas include gait analysis and efficient capture of pathological gaits.

Biomechanical Study on the Effect of Muscle Strength on Contact Characteristics of Foot Joints / 医用生物力学

Objective To explore the effect of mucle force on contact force, peak pressure and contact area of foot joint in in vitro biomechanical experiment of foot and ankle, so as to provide references for choosing appropriate loading modes. Methods In neutral position of the ankle joint, fresh calf and foot specimens were simulated with or without mucle force loading. The contact force, peak pressure and contact area of the 1st metatarsophalangeal joint, the 2nd metatarsophalangeal joint, the 1st tarsometatarsal joint, the 2nd tarsometatarsal joint, the medial cuneonavicular joint, the intermediate cuneonavicular joint, the talonavicular joint, the calcicocuboid joint, the subtalar joint ( posterior articular surface) and the tibiotalar joint of normal foot under loading were measured, the results are compared and analyzed. Results Under muscle force loading, the contact force of the 1st metatarsophalangeal joint, the 2nd metatarsophalangeal joint, the 1st tarsometatarsal joint,the 2nd tarsometatarsal joint, the medial cuneonavicular joint, the intermediate cuneonavicular joint, the talonavicular joint and the tibiotalar joint were significantly greater than those without muscle force loading (P<0. 05), and the change percentages were 719. 28% , 311. 37% , 128. 67% , 50. 82% , 54. 89% , 57. 63% ,79. 98% and 50. 34% , respectively. The peak pressures of the 1st metatarsophalangeal joint , the 1st tarsometatarsal joint and the talonavicular joint under muscle force loading were significantly higher than those without muscle force loading ( P < 0. 05), and the change percentages were 176. 14% , 62. 91% and 40. 07% ,respectively. The contact area of the 1st metatarsophalangeal joint, the 1st tarsometatarsal joint, the intermediate cuneonavicular joint and the subtalar joint ( posterior articular surface) under muscle force loading increased significantly (P<0. 05), and the change percentages were 132. 20% , 55. 41% , 30. 97% and 26. 87% , respectively. Conclusions In biomechanical experiment of foot and ankle specimens, muscle force loading has a significant effect on contact force, peak pressure and contact area of each foot joint, especially the forefoot.Therefore, it is necessary to consider the effect of muscle force loading on stress of foot and ankle in the study ofrelated in vitro specimens

Effects of Salt Ions, Polyethylene Glycol and Force on Twisted Structure of Double DNAs / 医用生物力学

Objective To investigate the effects of different salt ion concentration, polyethylene glycol (PEG) and force on structure of double DNAs braids. Methods Taking the 10 kb DNA as the research object, the effects of different concentrations of salt ions(Na+, K+, Mg2+), PEG and different forces on variation of relative extension of twisted double DNAs with rotation turns were investigated by flow chamber experiment of magnetic tweezers. Results The structure of double DNAs braids was sensitive to salt ion concentration but insensitive to PEG. With the increase of ion concentration, the extension of braids changed more gently with the rotation turns, and the electrostatic shielding saturation concentration of Mg 2+ was much lower than that of the monovalent cation. The effect of crowded environment on DNA was mainly the compression of contour length. The twisted structure of DNA was more stable under high force (above 4 pN), and fluctuated greatly under low force (lower than 2 pN). Conclusions The braiding structure and mechanical properties of DNA are affected by ion concentration in the solution and forces. The results may help to elucidate the mechanism of chromatin torsional torque affected by solution environment, and provide references for the function of topoisomerase under different solution conditions.

Progress of Cell Mechanics in 2022 / 医用生物力学

The mechanical microenvironment of cells plays a critical role in regulating the physiological function of cells. Cells in vivo are often subjected to a variety of mechanical forces from their mechanical micro-environment, such as shear, tension, and compression. At the same time, cells can adhere to the extracellular matrix (ECM) through adhesion molecules (such as integrin-ligand binding), and further sense the stiffness of the ECM. Cell mechanics mainly studies the properties and behavior of living cells under mechanical forces, and how they relate to cell functions. This review summarized the advances in cell mechanics in 2022, focusing on integrin-ligand interactions and the effects of matrix stiffness and mechanical forces on cell physiological behavior and morphogenesis.

Effects from Extramedullary Design of Femoral Stem on Hip Contact Force: A Musculoskeletal Multi-Body Dynamic Study / 医用生物力学

Objective To investigate the effects of design parameters such as neck-shaft angle, femoral offset and anteversion angle of total hip arthroplasty ( THA) prosthesis on contact forces of the hip. Methods A musculoskeletal multi-body dynamic model of THA was established based on AnyBody software. The effects of single or multiple factors on hip contact force were studied when the neck-shaft angle, eccentricity and anteversion angle varied within ±10°, ±20 mm and ±10°, respectively. Results The maximum hip contact force increased by 26. 08% when femoral offset was reduced by 20 mm. The maximum hip contact force increased by 5. 99% when the neck-shaft angle increased by 10°. When the anteversion angle increased by 10°, the hip contact force decreased at 0% -24% of gait cycle, with the peak decreasing by 19. 16% . However, the hip contact force was significantly increased at 38% -70% of gait cycle, with the peak increasing by 67. 78% . Conclusions In extramedullary design of the femoral stem, based on reconstruction of the patient’s anatomical parameters, the offset of the femoral stem can be appropriately increased, and the neck-shaft angle and anteversion angle can bereduced to avoid increasing forces on the hip.

Time-course changes of intraosseous environment and shear resistance mechanical properties of jawbone in SD rats with fluorosis / 环境与职业医学

Background At present, a large number of reports focus on the bones of limbs and trunk, while there are few studies on the effect of fluorosis on jawbone which is the inevitable structural basis for the development and treatment of oral diseases. Objective To preliminarily investigate the effect of fluoride exposure on the mechanical properties of jawbone by observing the changes in the intraosseous environment and the maximum load against shearing force (LSFmax) of the jawbone in rats with chronic fluoride treatment. Methods Screening experiment: 48 SD male rats were randomly divided into a control group and three fluoride exposure groups (50, 150, and 250 mg·L−1 fluoride concentration), 12 rats in each group. The fluoride exposure groups were molded by feeding different concentrations of sodium fluoride solution, and the control group drank tap water from Guizhou area. Each group was further divided into 4 subgroups with 3 animals each according to observation time points after 0, 2, 4, and 6 months. The LSFmax of the jawbone was measured with an electronic universal ergometer, the expression of type I collagen (Col1) was shown by Sirius red staining, and the expression of runt-related transcription factor 2 (Runx2) was determined semi-quantitatively by immunohistochemistry at selected time points. Formal experiment: 12 male SD rats were randomly divided into a fluoride exposure group and a control group. The fluoride exposure group were fed with 150 mg·L−1 sodium fluoride solution, and the control group drank tap water from Guizhou. After feeding with fluoride for 5 months, the ergometer was used to measure the LSFmax of the jawbone. Osteoclasts were counted after tartrate resistant acid phosphatase (TRAP) staining. Col1, Runx2, bone morphogenetic protein 2 (BMP-2), alkaline phosphatase (ALP), and cathepsin K (Cath K) were detected semi-quantitatively by immunohistochemistry expression and Sirius red staining. Micro computed tomography (Micro CT) was used to observe the trabecular bone microstructure. Results Screening experiment: The LSFmax of the control group and the 50 mg·L−1 fluoride exposure group reached the peak value at the 2nd month, and the LSFmax of the 50 mg·L−1 fluoride exposure group reached the valley value at the 4th month. The LSFmax of the 150 mg·L−1 fluoride exposure group at the 4th month was higher than that at the 6th month (P<0.05). There was no significant difference in the LSFmax at each time point in the 250 mg·L−1 fluoride exposure group. At the same time point, there was no statistically significant difference in LSFmax among the groups. The Col1 levels of the 50 mg·L−1, 150 mg·L−1, and 250 mg·L−1 fluoride exposure groups were higher than the time point 0 from the 2nd month (P＜0.05). The Runx2 showed no statistically significant difference by concentration or time. Formal experiment: After feeding with 150 mg·L−1 fluoride for 5 months, the LSFmax of the fluoride exposure group was greater than that of the control group (P<0.05). The expressions of Col1, Runx2, BMP2, ALP, and Cath K in the fluorosis exposure group were higher than those in the control group (P<0.05). There were no statistically significant differences in osteoclast count or indicators of bone trabecular microstructure. Conclusion Chronic fluoride exposure may increase the shear strength of jaw bone.

Musculoskeletal multibody dynamics investigation for the different medial-lateral installation position of the femoral component in unicompartmental knee arthroplasty / 生物医学工程学杂志

The surgical installation accuracy of the components in unicompartmental knee arthroplasty (UKA) is an important factor affecting the joint function and the implant life. Taking the ratio of the medial-lateral position of the femoral component relative to the tibial insert (a/A) as a parameter, and considering nine installation conditions of the femoral component, this study established the musculoskeletal multibody dynamics models of UKA to simulate the patients' walking gait, and investigated the influences of the medial-lateral installation positions of the femoral component in UKA on the contact force, joint motion and ligament force of the knee joint. The results showed that, with the increase of a/A ratio, the medial contact force of the UKA implant was decreased and the lateral contact force of the cartilage was increased; the varus rotation, external rotation and posterior translation of the knee joint were increased; and the anterior cruciate ligament force, posterior cruciate ligament force and medial collateral ligament force were decreased. The medial-lateral installation positions of the femoral component in UKA had little effect on knee flexion-extension movement and lateral collateral ligament force. When the a/A ratio was less than or equalled to 0.375, the femoral component collided with the tibia. In order to prevent the overload on the medial implant and lateral cartilage, the excessive ligament force, and the collision between the femoral component and the tibia, it is suggested that the a/A ratio should be controlled within the range of 0.427-0.688 when the femoral component is installed in UKA. This study provides a reference for the accurate installation of the femoral component in UKA.

O "ativo" jogador e sua produção no contexto da economia política do futebol: diálogos preliminares / The "asset" player and his production in the context of football's political economy: preliminar discussions / El jugador "activo" y su producción en el contexto de la economía política del fútbol: conversaciones previas

RESUMO Este artigo objetiva discutir a conceituação do "ativo" jogador de futebol, bem como sua repercussão dentro da indústria futebolística. A investigação foi caracterizada como exploratória e bibliográfica. Como principais achados, percebeu-se a relevância dos atletas para a produção de riqueza na modalidade, tanto na relação clube-clube como pelo vínculo clube-futebolista, notadamente a partir da reestruturação capitalista em sua fase tardia. Por outro lado, ao cotejar o "ativo" com o conceito de força de trabalho, concluiu-se pela necessidade de se problematizar a definição contábil de "ativo" como a mais apropriada para explicar a realidade, particularmente o processo de produção de valor pela indústria do futebol.

ABSTRACT This article aims to discuss the conceptualization of the "asset" football player, as well as its repercussion within the football industry. The investigation was characterized as exploratory and bibliographical. As main findings, the relevance of the athletes for the production of wealth in the modality was perceived, as much in the club-club relation, as by the club-footballer link, notably, from the capitalist restructuring in its late phase. On the other hand, when comparing the "asset" with the concept of work force, it was concluded that it is necessary to problematize the accounting definition of "asset" as the most appropriate one to explain reality, particularly, the process of production of value by the football industry.

RESUMEN Este artículo pretende discutir la conceptualización del futbolista "activo", así como su repercusión dentro de la industria del fútbol. La investigación se caracterizó como exploratoria y bibliográfica. Como principales hallazgos, se percibió la relevancia de los atletas para la producción de riqueza en la modalidad, tanto en la relación club-club, como por el vínculo club-futbolista, notablemente, a partir de la reestructuración capitalista en su fase tardía. Por otro lado, al comparar el "activo" con el concepto de fuerza de trabajo, se concluyó que es necesario problematizar la definición contable de "activo" como la más adecuada para explicar la realidad, en particular, el proceso de producción de valor por la industria del fútbol.

Assessment of Bite Forces in Restored Teeth with Different Commonly Used Restorative Materials: A Comparative Study

ABSTRACT Objective: To evaluate and compare bite force (BF) in permanent first molars restored with glass ionomer cement (GIC), composite and amalgam, and normal contralateral permanent first molars. Material and Methods: BF was recorded in decayed permanent first molars, which were filled with GIC (n=30), composite (n=30), and amalgam (n=30), and in healthy contralateral first molars (n=90) with Force Transducer Occlusal Force Meter and compared. Results: BF was significantly higher in normal teeth on the contralateral side compared to teeth restored with GIC and composite. However, in patients with amalgam restoration, though it was less compared to that on the contralateral side, it was not statistically significant (p>0.05). Conclusion: Restoring teeth with various filling materials may improve bite force. In the present study, it was found that the teeth restored with amalgam had higher bite forces in comparison to the other restorative materials used. However, it was not comparable to that observed in the normal tooth (control) on the contralateral side.

How does arch form and interproximal contact size affect the 3D displacements and rotations of teeth: a finite element analysis

ABSTRACT Objective: The objective of this study was to determine how arch form and interproximal contact size displace mandibular teeth subjected to an anterior component of force (ACF). Methods: Nine finite element models (FEM) of the mandibular arch were developed using Ansys® v. 16.0 software. They were designed to evaluate the effects of three arch forms (triangular, oval, and square) and three contact sizes (point-to-point, 1 mm diameter, and 2 mm diameter). All nine models were subjected to an ACF of 53.8 N (5486 gm). Three-dimensional tooth rotations and displacements of the mandibular teeth were evaluated, from the right first molar to the left first molar. Results: Arch form had a greater effect on tooth movements than contact size. Triangular arches and point-to-point contacts produced the greatest displacements and rotations of teeth. Oval arches with 2 mm wide interproximal contact points showed the greatest stability. The right first premolar showed the greatest displacements in all of the models. Conclusions: Arch form and contact size affect interproximal tooth stability. Teeth are least stable in narrow arches with point-to-point interproximal contacts, and most stable in wider arches with larger contacts.

RESUMO Objetivo: O objetivo deste estudo foi determinar como o formato da arcada e o tamanho do contato interproximal deslocam os dentes inferiores submetidos a um componente anterior de força (CAF). Métodos: Nove modelos de elementos finitos (MEF) da arcada inferior foram desenvolvidos utilizando o software Ansys® v. 16.0. Eles foram projetados para avaliar os efeitos de três formatos de arcada (triangular, oval e quadrado) e três tamanhos de contato interproximal (ponto a ponto, 1 mm de diâmetro e 2 mm de diâmetro). Todos os nove modelos foram submetidos a um CAF de 53,8 N (5486 gm). Foram avaliados tridimensionalmente as rotações dentárias e os deslocamentos dos dentes inferiores, do primeiro molar direito ao primeiro molar esquerdo. Resultados: A forma da arcada teve um efeito maior no movimento dos dentes do que o tamanho do contato interproximal. Arcadas triangulares e contatos ponto a ponto produziram os maiores deslocamentos e rotações dos dentes. Arcadas ovais com pontos de contato interproximal de 2 mm de largura apresentaram maior estabilidade. O primeiro pré-molar direito apresentou os maiores deslocamentos em todos os modelos. Conclusões: O formato da arcada e o tamanho do contato interproximal afetam a estabilidade dos dentes. Os dentes foram menos estáveis nas arcadas estreitas com contatos interproximais ponto a ponto, e mais estáveis nas arcadas mais largas com contatos maiores.

Dependência, ciclo do capital e limites do fundo público no Brasil / Dependency, capital cycle and limits of the public fund in Brazil

Resumo: Este artigo visa identificar a participação e os limites do fundo público no ciclo do capital da economia dependente brasileira. Para isso, aborda as implicações do intercâmbio desigual, da transferência de valor e da superexploração da força de trabalho para a composição e direcionamento do fundo público no Brasil, utilizando-se da coleta e análise de dados acerca do sistema tributário brasileiro.

Abstract: This article aims to identify the participation and limits of the public fund in the capital cycle of the Brazilian dependent economy. To this end, it addresses the implications of unequal exchange, value transfer and overexploitation of the labor force for the composition and direction of public fund in Brazil, using the analysis of data about the Brazilian tax system.

Superexploração da força de trabalho: uma proposta metodológica de análise / Superexploitation of the labor force: a methodological proposal for analysis

Resumo: O presente ensaio propõe uma análise quantitativa da superexploração da força de trabalho, especialmente por meio de mecanismos que vinculem a intensificação da exploração da força de trabalho às transferências estruturais de valor da periferia ao centro. Nosso propósito é esboçar breves notas metodológicas que contribuam com os esforços incipientes de análise quantitativa da superexploração, avançando em relação a eles, sobretudo mediante o reconhecimento dos limites desses esforços.

Abstract: This essay proposes a quantitative analysis of the superexploitation of the labor force, especially through mechanisms that link the intensification of the exploitation of the labor force to structural transfers of value from the periphery to the center. Our purpose is to outline brief methodological notes that contribute to the incipient efforts of quantitative analysis of superexploitation, moving forward in relation to them, especially based on a recognition of the limits of these efforts.

The Effects of Different Degrees of Leg Length Discrepancy on Vertical Ground Reaction Force in Children and Adults: Treatment Implications

@#Introduction: Previous studies on the degree of leg length discrepancy that causes limb biomechanical problems did not differentiate between adults and children. We conducted this study to determine the effects of simulated leg length discrepancy on vertical ground reaction force in children and adults to enable decision-making for intervention in patients with leg length discrepancy for different age groups or heights. Materials and methods: This cross-sectional study involved male volunteers of children 150cm and adults with 170cm in height. Vertical ground reaction force was measured using a gait analysis study. The first measurement was taken without any leg length discrepancy as a baseline. Subsequently, different amounts of leg length discrepancy were simulated on the left leg with shoe lifts of 2, 3, and 4cm. The measurements were repeated on each volunteer with similar shoe lifts on the right leg. Therefore, 14 volunteers provided simulations of 28 leg length discrepancies for each group. The first and second peaks of vertical ground reaction force were separately analysed. The vertical GRF of a simulated leg length discrepancy was compared with the baseline. Repeated measurement of analysis of variance (ANOVA) within each group was done. Results: In both groups, the second peak of vertical ground reaction force in the longer leg reduced gradually as the shoe lift increased sequentially from 2 to 3cm and then to 4cm. A discrepancy of 3cm and above was statistically significant to cause a reduction in the vertical GRF on the longer limb in both height groups. Conclusion: The degree of leg length discrepancy that caused significant changes in second peak ground reaction force in children with 150 and adults with 170cm height population was similar at 3cm. Therefore, the cut-off point for intervention for both groups are similar with additional consideration of future growth in children.