Alzheimer's disease biomarkers and their current use in clinical research and practice.

While blood-based tests are readily available for various conditions, including cardiovascular diseases, type 2 diabetes, and common cancers, Alzheimer's disease (AD) and other neurodegenerative diseases lack an early blood-based screening test that can be used in primary care. Major efforts have been made towards the investigation of approaches that may lead to minimally invasive, cost-effective, and reliable tests capable of measuring brain pathological status. Here, we review past and current technologies developed to investigate biomarkers of AD, including novel blood-based approaches and the more established cerebrospinal fluid and neuroimaging biomarkers of disease. The utility of blood as a source of AD-related biomarkers in both clinical practice and interventional trials is discussed, supported by a comprehensive list of clinical trials for AD drugs and interventions that list biomarkers as primary or secondary endpoints. We highlight that identifying individuals in early preclinical AD using blood-based biomarkers will improve clinical trials and the optimization of therapeutic treatments as they become available. Lastly, we discuss challenges that remain in the field and address new approaches being developed, such as the examination of cargo packaged within extracellular vesicles of neuronal origin isolated from peripheral blood.

Mesenchymal Stem Cells Increase Resistance Against Ventricular Arrhythmias Provoked in Rats with Myocardial Infarction.

This study evaluated the role of the mesenchymal stem cells derived from adipose tissue (MSCs) in provoked ventricular arrhythmias (VAs) in animals with myocardial infarction (MI). The experimental groups were: sham, subjected to sham surgery and intramyocardial saline injection; MIV, infarcted rats subjected to intramyocardial saline injection; MI + MSCs, infarcted rats subjected to intramyocardial MSCs injection. Injections were performed two days after infarction and the arrhythmogenic inducibility experiment was performed the next day. Only 35% of the MI + MSCs group developed VAs, while the one in the MIV group was 65%. The proportion of nonsustained ventricular tachycardia, sustained tachycardia, and ventricular fibrillation was similar between the infarcted groups, but MSCs animals had shorter duration of nonsustained ventricular tachycardia. However, MSCs increased connexin 43 content in the remote area, even above the levels found in the sham group. MSCs prevented the increase of IL-1ß in the different areas of the myocardium. There was higher carbonylation and content of 4-hydroxynonenal (4-HNE, a marker of lipoperoxidation) in the myocardium of infarcted rats, but MSCs attenuated the increase of 4-HNE in the infarcted area. In conclusion, MSCs have a protective effect against the development of arrhythmias, but do not imply a significant benefit for animals that have developed VAs. It is possible to think that the cardioprotection of MSCs involves anti-inflammatory/oxidative actions and improvement in the formation of communicating junctions.Graphical abstract.

An Intramyocardial Mass Mimicking ST-Segment Elevation Myocardial Infarct at Presentation.

ST-segment elevation on the electrocardiogram typically indicates acute myocardial infarction but can mimic ST-segment elevation myocardial infarction in various conditions. We present a case of a patient with an intramyocardial mass and anterior ST-segment elevation without significant myocardial biomarker elevation. Multimodality imaging was crucial in revealing cardiac metastasis as the attributable cause.

Endoscopic transmural resection as an alternative to colorectal surgery after high-risk (non-curative) endoscopic resection.

Endoscopic full-thickness resection (eFTR) is an emerging technique that enables effective and safe management of complex colorectal lesions. The full-thickness resection device (FTRD®, Ovesco, Germany) has primarily been used for non-exposed transmural resection of challenging subepithelial or epithelial lesions, where conventional methods may be limited. This technique represents an alternative to surgery in selected patients, and its applications are rapidly expanding. In recent years, eFTR has been described as an alternative to surgery for scars aiming to exclude residual tumors after non-curative endoscopic resection. We present a case of a 41-year-old woman with Lynch syndrome (dMLH1) with rectal adenocarcinoma at the age of 20 underwent anterior resection of the rectum and adjuvant chemoradiotherapy. At the age of 39, during endoscopic surveillance, she presented with a suspicious lesion (Paris 0-Is+IIa, NICE2, JNET2B) measuring 16mm in the hepatic angle, and underwent en bloc endoscopic mucosal resection (EMR). Histopathological analysis revealed a low-grade invasive adenocarcinoma with lymphoid stroma with deep invasion of the submucosa and resection margin involvement (vertical R1). After a multidisciplinary team discussion, complementary surgery was proposed but the patient refused, opting for close endoscopic and imaging surveillance. Two subsequent colonoscopies plus computed tomography (CT) scans showed no signs of macro or microscopic residual or recurrent tumor, even after extensive biopsies of the colonic scar. However, a CT scan 20months post-resection showed a de novo 2cm thickening of the parietal wall in the hepatic angle, consistent with the location of the previous endoscopic resection. Suspecting deep parietal tumor recurrence without superficial endoscopic findings, a transmural endoscopic resection using FTRD® of the EMR scar was performed, whose histology revealed no transparietal tumor recurrence.

A rare LMNA missense mutation causing a severe phenotype of mandibuloacral dysplasia type A: a case report.

OBJECTIVE: To report the case of a girl presenting a severe phenotype of mandibuloacral dysplasia type A (MADA) characterized by prominent osteolytic changes and ectodermal defects, associated with a rare homozygous LMNA missense mutation (c.1579C>T). CASE DESCRIPTION: A 6-year-old girl was evaluated during hospitalization exhibiting the following dysmorphic signs: subtotal alopecia, dysmorphic facies with prominent eyes, marked micrognathia and retrognathia, small beaked nose, teeth crowding and thin lips, generalized lipodystrophy, narrow and sloping shoulders, generalized joint stiffness and bone reabsorption in the terminal phalanges. In dermatological examination, atrophic skin, loss of cutaneous elasticity, hyperkeratosis, dermal calcinosis, and hyperpigmented and hypochromic patches were observed. Radiology exams performed showed bilateral absence of the mandibular condyles, clavicle resorption with local amorphous bone mass confluence with the scapulae, shoulder joints with subluxation and severe bone dysplasia, hip dysplasia, osteopenia and subcutaneous calcifications. COMMENTS: MADA is a rare autosomal recessive disease caused by mutations in LMNA gene. It is characterized by craniofacial deformities, skeletal anomalies, skin alterations, lipodystrophy in certain regions of the body and premature ageing. Typical MADA is caused by the p.R527H mutation in the LMNA gene. However, molecular analysis performed from oral epithelial cells obtained from the patient showed the rare mutation c.1579C>T, p. R527C in the exon 9 of LMNA. This is the sixth family identified with this mutation described in the literature.

A framework for longitudinal latent factor modelling of treatment response in clinical trials with applications to Psoriatic Arthritis and Rheumatoid Arthritis.

OBJECTIVE: Clinical trials involve the collection of a wealth of data, comprising multiple diverse measurements performed at baseline and follow-up visits over the course of a trial. The most common primary analysis is restricted to a single, potentially composite endpoint at one time point. While such an analytical focus promotes simple and replicable conclusions, it does not necessarily fully capture the multi-faceted effects of a drug in a complex disease setting. Therefore, to complement existing approaches, we set out here to design a longitudinal multivariate analytical framework that accepts as input an entire clinical trial database, comprising all measurements, patients, and time points across multiple trials. METHODS: Our framework composes probabilistic principal component analysis with a longitudinal linear mixed effects model, thereby enabling clinical interpretation of multivariate results, while handling data missing at random, and incorporating covariates and covariance structure in a computationally efficient and principled way. RESULTS: We illustrate our approach by applying it to four phase III clinical trials of secukinumab in Psoriatic Arthritis (PsA) and Rheumatoid Arthritis (RA). We identify three clinically plausible latent factors that collectively explain 74.5% of empirical variation in the longitudinal patient database. We estimate longitudinal trajectories of these factors, thereby enabling joint characterisation of disease progression and drug effect. We perform benchmarking experiments demonstrating our method's competitive performance at estimating average treatment effects compared to existing statistical and machine learning methods, and showing that our modular approach leads to relatively computationally efficient model fitting. CONCLUSION: Our multivariate longitudinal framework has the potential to illuminate the properties of existing composite endpoint methods, and to enable the development of novel clinical endpoints that provide enhanced and complementary perspectives on treatment response.

Optimization and Characterization of Interspecific Hybrid Crude Palm Oil Unaué HIE OxG Nanoparticles with Vegetable By-Products as Encapsulants.

Interspecific hybrid crude palm oil (HCPO) HIE OxG derived from crossbred African oil palm (Elaeis guineensis) and American Caiaué (Elaeis oleifera) is prominent for its fatty acid and antioxidant compositions (carotenoids, tocopherols, and tocotrienols), lower production cost, and high pest resistance properties compared to crude palm oil. Biodegradable and sustainable encapsulants derived from vegetable byproducts were used to formulate HCPO nanoparticles. Nanoparticles with hybrid crude palm oil and jackfruit seed flour as a wall material (N-JSF) and with hybrid crude palm oil and jackfruit axis flour as a wall material (N-JAF) were optimized using a 22 experimental design. They exhibited nanoscale diameters (<250 nm) and were characterized based on their zeta potential, apparent viscosity, pH, color, and total carotenoid content. The nanoparticles demonstrated a monodisperse distribution, good uniformity, and stability (polydispersity index < 0.25; zeta potentials: N-JSF -19.50 ± 1.47 mV and N-JAF -12.50 ± 0.17 mV), as well as high encapsulation efficiency (%) (N-JSF 86.44 ± 0.01 and N-JAF 90.43 ± 1.34) and an optimal carotenoid retention (>85%). These nanoparticles show potential for use as sustainable and clean-label HCPO alternatives in the food industry.

A long rectal foreign body successfully removed after colonoscopy.

A man in his 70s, without prior foreign body history, presented to the emergency department 15 days after accidentally inserting a tubular object into his anus. He reported a reduction in normal bowel movements. Initial physical examination was normal. An abdominal X-ray revealed a tubular hypodensity in the pelvic region, without perforation. Subsequently, it was decided to perform a colonoscopy during which a foreign body was visualized in the distal rectum, that was successfully removed with the use of a rat tooth forceps. The foreign body was a plastic tube about 18cm in size. Afterwards, the rest of the colon was assessed, having identified an ulcer in the lower rectum related to the presence of the object. Six months later, the patient reported no complains and a follow-up colonoscopy was conducted which was normal. Discussion: Rectal foreign bodies, whose size and shape are variable and sometimes aberrant, are often self-inserted for self-gratification by adults, and its incidence is increasing. Patients typically avoid immediate medical attention and seek help only when complications arise. Formal clinical guidelines are lacking, and this case illustrates the importance of clinical judgement in the management of rectal foreign bodies, whether endoscopic or surgical.

A rare LMNA missense mutation causing a severe phenotype of mandibuloacral dysplasia type A: a case report / Uma rara mutação missense no gene LMNA causando um fenótipo grave de displasia mandibuloacral tipo A: relato de caso

ABSTRACT Objective: To report the case of a girl presenting a severe phenotype of mandibuloacral dysplasia type A (MADA) characterized by prominent osteolytic changes and ectodermal defects, associated with a rare homozygous LMNA missense mutation (c.1579C>T). Case description: A 6-year-old girl was evaluated during hospitalization exhibiting the following dysmorphic signs: subtotal alopecia, dysmorphic facies with prominent eyes, marked micrognathia and retrognathia, small beaked nose, teeth crowding and thin lips, generalized lipodystrophy, narrow and sloping shoulders, generalized joint stiffness and bone reabsorption in the terminal phalanges. In dermatological examination, atrophic skin, loss of cutaneous elasticity, hyperkeratosis, dermal calcinosis, and hyperpigmented and hypochromic patches were observed. Radiology exams performed showed bilateral absence of the mandibular condyles, clavicle resorption with local amorphous bone mass confluence with the scapulae, shoulder joints with subluxation and severe bone dysplasia, hip dysplasia, osteopenia and subcutaneous calcifications. Comments: MADA is a rare autosomal recessive disease caused by mutations in LMNA gene. It is characterized by craniofacial deformities, skeletal anomalies, skin alterations, lipodystrophy in certain regions of the body and premature ageing. Typical MADA is caused by the p.R527H mutation in the LMNA gene. However, molecular analysis performed from oral epithelial cells obtained from the patient showed the rare mutation c.1579C>T, p. R527C in the exon 9 of LMNA. This is the sixth family identified with this mutation described in the literature.

RESUMO Objetivo: Relatar o caso de uma jovem que apresentava um fenótipo grave de displasia mandibuloacral tipo A (MADA) caracterizado por alterações osteolíticas proeminentes e defeitos ectodérmicos, associados a uma rara mutação homozigótica missense no gene LMNA (c.1579C>T). Descrição do caso: Uma menina de seis anos foi avaliada durante hospitalização apresentando os seguintes sinais dismórficos: alopecia subtotal, fácies dismórfica com olhos proeminentes, micrognatia e retrognatia acentuada, nariz pequeno e adunco, dentes apinhados e lábios finos, lipodistrofia generalizada, ombros estreitos e inclinados, rigidez articular e reabsorção óssea nas falanges terminais. Ao exame dermatológico, observou-se pele atrófica, perda da elasticidade cutânea, hiperceratose, calcinose dérmica e manchas hiperpigmentadas e hipocrômicas. Exames radiológicos realizados mostraram ausência de côndilos mandibulares bilaterais, reabsorção da clavícula com massa óssea amorfa local confluindo com as escápulas, articulações do ombro com subluxação e displasia óssea severa, com displasia coxofemoral, osteopenia e calcificações subcutâneas. Comentários: MADA é uma doença autossômica recessiva rara causada por mutações no gene LMNA. Caracteriza-se por deformidades craniofaciais, anomalias esqueléticas, alterações cutâneas, lipodistrofia em determinadas regiões do corpo e envelhecimento precoce. MADA típica é causada pela mutação p.R527H no gene LMNA. No entanto, a análise molecular realizada com células epiteliais orais obtidas da paciente mostrou a mutação rara c.1579C>T, p. R527C no exon 9 do gene LMNA. Esta é a sexta família identificada com essa mutação descrita na literatura.

Caracterização e relação entre variáveis sociodemográficas e prática de atividade física entre adultos / Characterization and relationship between sociodemographic variables and physical activity among adults

Introdução: A realização de atividade física está associada a benefícios à saúde, incluindo bem-estar físico, psicológico e social. A modernidade com sua forma de organização e avanços tem se caracterizado pela diminuição da prática por vários motivos, implicando em consequências aos indivíduos. Objetivo: Analisar a associação entre variáveis sociodemográficas, prática de atividade física e Questionário de Atividade Física (IPAQ). Método: Este estudo transversal de base populacional foi realizado com 526 adultos em um município do Piauí de 2018 a 2021. Foram coletadas variáveis sociodemográficas, prática de atividade física e variáveis referentes ao IPAQ. As análises estatísticas foram realizadas usando os testes Exato de Fisher e U de Mann Whitney. Resultados: A maioria dos participantes eram do sexo feminino, autodeclarados pardos, casados ou em união estável, católicos, com ensino médio completo, trabalho e idade média de 38,57 (38,6) anos. A maioria dos participantes (54,2%) foi classificada como sendo "ativos" quanto às práticas de atividade física, estando essa variável associada ao sexo feminino. As demais variáveis não mostraram associação significativa. Conclusão: As variáveis sociodemográficas e de prática de atividade física estão relacionadas principalmente com o sexo.

Introduction: Physical activity is associated with health benefits, including physical, psychological, and social well-being. Modernity, with its form of organization and advances, has been characterized by a decrease in the practice of physical activity for various reasons, resulting in consequences for individuals. Objective: To analyze the association between sociodemographic variables, practice of physical activity, and the Physical Activity Questionnaire (IPAQ). Method: This population-based cross-sectional study was carried out with 526 adults in a municipality of Piauí from 2018 to 2021. Sociodemographic variables, physical activity practice, and variables related to IPAQ were collected. Statistical analyzes were performed using the Fisher's Exact and Mann Whitney U tests. Results: Most participants were female, self-declared brown skin, married or in a stable union, Catholic, with high school education, job, and a mean age of 38.57 (38.6) years. Most participants (54.2%) were classified as "active" in terms of physical activity, and this variable was associated with the female gender. Other variables showed a non-significant association. Conclusion: Sociodemographic variables and the practice of physical activity are related especially when gender is considered.

Construção e validação de material educativo para promoção da alimentação complementar infantil / Construction and validation of educational material to promote complementary infant feeding

A introdução alimentar inadequada pode resultar em consequências danosas para a saúde infantil, o que ressalta a importância da utilização de métodos direcionados para a promoção da alimentação adequada aos menores de dois anos. Neste estudo apresenta-se o processo de construção e validação de uma cartilha educativa para promoção da alimentação complementar às crianças menores de dois anos de idade. Trata-se de uma pesquisa metodológica, de validação, realizada na cidade de Picos - Piauí. A cartilha foi construída com base em diagnóstico situacional e publicações. A validação do conteúdo se deu mediante consulta realizada a especialistas nas áreas de interesse e às mães com filhos menores de dois anos em Unidades Básicas de Saúde do município. A cartilha foi validada quanto ao seu conteúdo, linguagem e ilustrações pelos juízes, apresentando Índice de Validade de Conteúdo global de 0,87 e, quanto à sua organização, estilo de escrita, aparência e motivação, apresentando 94,93% de aprovação do público-alvo. Dessa forma, a tecnologia educativa desenvolvida mostrou-se um material que pode ser utilizado como ferramenta estratégica para a promoção da saúde de menores de dois anos de idade por meio do incentivo a hábitos alimentares saudáveis.

Inadequate food introduction can result in harmful consequences for children's health, which highlights the importance of using methods aimed at promoting adequate food for children under two years of age. This study presents the construction and validation process of an educational booklet to promote complementary feeding for children under two years of age. This is a methodological research, validation, carried out in the city of Picos - Piauí. The booklet was built based on situational diagnosis and publications. Content validation was carried out through consultation with specialists in the areas of interest and mothers with children under two years of age, in Basic Health Units in the municipality. The booklet was validated for its content, language and illustrations by the judges, presenting a global Content Validity Index of 0.87 and for its organization, writing style, appearance and motivation, presenting 94.93% approval from the target audience. Thus, the educational technology developed proved to be a material that can be used as a strategic tool for promoting the health of children under two years of age by encouraging healthy eating habits.

Rectal ultrasound as unique diagnostic option in obstructive colorectal metastasis from breast adenocarcinoma.

We present the case of an uncommon manifestation of metastatic breast cancer as an occlusive colorectal stenosis with submucosal location. The endoscopic rectal ultrasound allowed to confirm the diagnosis with transmural biopsies.

Effect of carotenoid pigments extracted from papaya epicarp (Carica papaya) on the characteristics of Frankfurt sausages

The industrialization of papaya generates a large amount of organic waste, which is rich in antioxidant compounds, especially carotenoids. The purpose of the present article was to study the influence of carotenoid pigments extracted from the papaya epicarp as a partial substitute for nitrites in Frankfurt sausages. Four concentrations of lipid extract of papaya epicarp were analyzed in said sausages. While the control sample had 0 % substitution, 25 %, 50 % and 75 % substitution of nitrite was added to the other samples. The sausages were kept at 6 ± 2 °C for 30 days. The chemical composition, pH, water holding capacity, water activity, emulsion stability, color coordinates, texture profile and sensory appearance were analyzed, and for the sausage that presented the best physicochemical parameters, the stability in the time at 0, 10, 20 and 30 days of storage. It was obtained that adding the papaya epicarp extract to a concentration of 25 % did not affect the physicochemical parameters. In addition, the texture and color characteristics, as well as the sensory evaluation showed the best results for said concentration, guaranteeing stability up to a period of 30 days of storage under vacuum packing conditions and under refrigeration (6 ± 2 °C). A new alternative is proposed to minimize the negative action of nitrites in analyzed Frankfurt sausages, replacing them with antioxidant compounds obtained from a raw material of vegetable origin.

La industrialización de la papaya genera residuos orgánicos, ricos en compuestos antioxidantes, especialmente, en carotenoides. El objetivo de la presente investigación fue estudiar la influencia de los pigmentos carotenoides extraídos de epicarpio de la papaya, como sustituto parcial de los nitritos en salchichas Frankfurt. En dichos embutidos, se analizaron cuatro concentraciones de extracto lipídico de epicarpio de papaya; mientras que la mezcla control tenía 0 % de sustitución, se añadió 25, 50 y 75 % de reemplazo de nitrito a las otras muestras. Las salchichas se mantuvieron a 6 ± 2 °C durante 30 días. Se analizó la composición química, el pH, la capacidad de retención de humedad, la actividad de agua, la estabilidad de la emulsión, las coordenadas de color, el perfil de textura y la apariencia sensorial y para el embutido que presentó los mejores parámetros fisicoquímicos, la estabilidad en el tiempo a 0, 10, 20 y 30 días de almacenamiento. Se obtuvo que la adición del extracto de epicarpio de papaya a una concentración del 25 % no afectó los parámetros fisicoquímicos. Además, las características de textura y color, así como la evaluación sensorial, mostraron los mejores resultados para dicha concentración, garantizando la estabilidad, hasta un periodo de 30 días de almacenamiento, en condiciones de envasado al vacío y en refrigeración (6 ± 2°C). Se propone una nueva alternativa para minimizar la acción negativa de los nitritos en las salchichas Frankfurt, sustituyéndolos por compuestos antioxidantes, obtenidos a partir de una materia prima de origen vegetal.

Confiabilidade teste-reteste de um protocolo de coleta do sinal eletromiográfico do músculo masseter em indivíduos com disfunção temporomandibular / Test-retest reliability of a protocol for recording the electromyographic signal from the masseter muscle on patients with temporomandibular disorders

Introdução: A eletromiografia (EMG) tem sido utilizada para avaliar alterações no sistema mastigatório proporcionada pela disfunção temporomandibular (DTM). Objetivos: Verificar a confiabilidade teste-reteste de um protocolo de coleta do sinal EMG do músculo masseter em indivíduos com DTM. Métodos: Estudo transversal composto por 20 indivíduos com DTM. Os testes foram realizados em duas sessões com 7 dias de intervalo. O sinal EMG foi avaliado pelas variáveis integral (iEMG) e a raiz quadrada da média do sinal (RMS). Resultados: Na análise intradia a confiabilidade para o RMS (ICC2,k: 0.85 a 0.96 ) e iEMG ICC2,k: 0.85 a 0.95) foi excelente, enquanto que a confiabilidade teste/reteste foi pobre para ambas as variáveis RMS (ICC2,1: 0.03 a 0.29) e iEMG (ICC2,1: 0.08 a 0.39). Conclusões: O protocolo de coleta do sinal EMG do músculo masseter em indivíduos com DTM demonstrou que os dados são reprodutíveis somente na mesma sessão de coletas enquanto que, para coletas em dias alternados a confiabilidade foi pobre.

Introduction: Electromyography (EMG) has been used to assess alterations in the masticatory system caused by temporomandybular disorders (TMD). Objectives: The aim of this study was to verify the test-retest reliability of a protocol for recording the EMG signal from masseter muscle in TMD patients. Methods: This is a cross-sectional study comprising 20 individuals with TMD. Tests were performed in two sessions 7 days apart. The EMG signal was evaluated by the variables integral (iEMG) and the root mean square of the signal (RMS). Results: In the intraday analysis the reliability for the RMS (ICC2,k: 0.85 to 0.96) and iEMG (ICC2,k: 0.85 to 0.95) was excellent, while the test/retest reliability was poor for both RMS (ICC2,1: 0.03 to 0.29) and iEMG (ICC2,1: 0.08 to 0.39) variables. Conclusions: The protocol for collecting the EMG signal from the masseter muscle in an individual with TMD demonstrated that the data are reproducible only in the same recording session, whereas for c recording on alternate days, the reliability was poor.

Cyclic fatigue resistance of three reciprocating nickel-titanium instruments with heat treatment at intrachannel temperature / Resistencia a la fatiga cíclica de tres instrumentos alternativos de níquel-titanio con tratamiento térmico a temperatura intracanal

Introduction: the in vitro study compared the dynamic cyclic fatigue resistance of 3 reciprocating NiTi files with heat treatment. Methods: we distributed 30 new endodontic files in three groups. The endodontic files selected for this experiment were: AF Blue R3 25/06 (AFB) (Fanta Dental, Shanghai, China), X1 Blue File 25/06 (X1B) (MK Life, Porto Alegre, RS, Brazil), and Reciproc Blue 08/25 (RB) (VDW, Munich, Germany. We measured the time to file fractureand the length of the fractured fragment. ANOVA analysis was used, followed by the Tukey test for multiple comparisons, with a significance level of 5% (P < 0,05). Results: the mean time in seconds until the file fractured was 170.7 ±15,1 for AFB files, 110,4 ±26,8 for X1B, and 163,3 ±22,9 for RB files. This difference was statistically significant when comparing X1B to AFB (p: 0,000) and X1B to RB (p: 0,000). However, there are no statistically significant differences between RB and AFB (p:0,739). Conclussions: this study found that RB and AFB files exhibit similar resistance to cyclic fatigue.

Introducción: el estudio in vitro comparó la resistencia a la fatiga cíclica dinámica de 3 limas NiTi recíprocas con tratamiento térmico. Métodos: distribuimos 30 limas endodónticas nuevas en tres grupos. Las limas endodónticas seleccionadas para este experimento fueron: AF Blue R3 25/06 (AFB) (Fanta Dental, Shanghai, China), X1 Blue File 25/06 (X1B) (MK Life, Porto Alegre, RS, Brasil), y Reciproc Blue 08/25 (RB) (VDW, Munich, Alemania. Se midió el tiempo transcurrido hasta la fractura de la lima y la longitud del fragmento fracturado. Se utilizó el análisis ANOVA, seguido de la prueba de Tukey para comparaciones múltiples, con un nivel de significación del 5% (P < 0.05). Resultados: el tiempo medio en segundos hasta la fractura de la lima fue de 170.7 ±15.1 para las limas AFB, 110.4 ±26.8 para las X1B y 163.3 ±22.9 para las RB. Esta diferencia fue estadísticamente significativa al comparar X1B con AFB (p: 0.000) y X1B con RB (p: 0.000). Sin embargo, no hay diferencias estadísticamente significativas entre RB y AFB (p:0.739). Conclusiones: en este estudio se ha comprobado que las limas RB y AFB presentan una resistencia similar a la fatiga cíclica.

How great is the stabilization of crowded polyphenylbiphenyls by London dispersion?

Decaphenylbiphenyl (1) and 2,2',4,4',6,6'-hexaphenylbiphenyl (2) are bulky molecules expected to be greatly destabilized by steric crowding. Herein, through a combined experimental and computational approach, we evaluate the molecular energetics of crowded biphenyls. This is complemented by the study of phase equilibria for 1 and 2. Compound 1 shows a rich phase behavior, displaying an unusual interconversion between two polymorphs. Surprisingly, the polymorph with distorted molecules of C1 symmetry is found to have the highest melting point and to be the one that is preferentially formed. The thermodynamic results also indicate that the polymorph displaying the more regular D2 molecular geometry has larger heat capacity and is probably the more stable at lower temperatures. The melting and sublimation data clearly reveal the weakening of cohesive forces in crowded biphenyls due to the lower molecular surface area. The experimental quantification of the intramolecular interactions in 1 and 2 indicated, using homodesmotic reactions, a molecular stabilization of about 30 kJ mol-1. We attribute the origin of this stabilization in both compounds to the existence of two parallel-displaced π⋯π interactions between the ortho-phenyl substituents on each side of the central biphenyl. Computational calculations with dispersion-corrected DFT methods underestimate the stabilization in 1, unless the steric crowding is well balanced in a homodesmotic scheme. This work demonstrates that London dispersion forces are important in crowded aromatic systems, making these molecules considerably more stable than previously thought.

AAPM task group report 275.S: Survey strategy and results on plan review and chart check practices in US and Canada.

BACKGROUND: AAPM Task Group (TG) 275 was charged with developing practical, evidence-based recommendations for physics plan and chart review clinical processes for radiation therapy. As part of this charge, and to characterize practices and clinical processes, a survey of the medical physics community was developed and conducted. Detailed analyses and trends based on the survey that exceeded TG report length constraints are presented herein. AIMS: The design, development, and detailed results of the TG- 275 survey as well as statistical analysis and trends are described in detail. This is complementary material to the TG 275 report. METHODS AND MATERIALS: The survey consisted of 100 multiple-choice questions divided into four main sections: 1) Demographics, 2) Initial Plan Check, 3) On-Treatment, and 4) End-of-Treatment Chart Check. The survey was released to all AAPM members who self-reported working in the radiation oncology field, and it was kept open for 7 weeks. Results were summarized using descriptive statistics. To study practice differences, tests of association were performed using data grouped by four demographic questions: 1) Institution Type, 2) Average number of patients treated daily, 3) Radiation Oncology Electronic Medical Record, and 4) Perceived Culture of Safety. RESULTS: The survey captured 1370 non-duplicate entries from the United States and Canada. Differences across practices were grouped and presented based on Process-Based and Check-Specific questions. A risk-based summary was created to show differences amongst the four demographic questions for checks associated with the highest risk failure modes identified by TG-275. CONCLUSION: The TG-275 survey captured a baseline of practices on initial plan, on-treatment, and end-of-treatment checks across a wide variety of clinics and institutions. The results of test of association showed practice heterogeneities as a function of demographic characteristics. Survey data were successfully used to inform TG-275 recommendations.

Thermoelectric Properties of Nickel and Selenium Co-Doped Tetrahedrite.

As the search continues for novel, cheaper, more sustainable, and environmentally friendly thermoelectric materials in order to expand the range of applications of thermoelectric devices, the tetrahedrite mineral (Cu12Sb4S13) stands out as a potential candidate due to its high abundance, low toxicity, and good thermoelectric performance. Unfortunately, as most current thermoelectric materials achieve zTs above 1.0, ternary tetrahedrite is not a suitable alternative. Still, improvement of its thermoelectric performance has been achieved to zTs ≈ 1 via isovalent doping and composition tuning, but most studies were limited to a single doping element. This project explores the effects of simultaneous doping with nickel and selenium in the thermoelectric properties of tetrahedrite. Simulated properties for different stoichiometric contents of these dopants, as well as the measured thermoelectric properties of the correspondent materials, are reported. One of the samples, Cu11.5Ni0.5Sb4S12.5Se0.5, stands out with a high power factor = 1279.99 µW/m·K2 at 300 K. After estimating the thermal conductivity, a zT = 0.325 at 300 K was obtained for this composition, which is the highest for tetrahedrites for this temperature. However, analysis of the weighted mobility shows the presence of detrimental factors, such as grain boundaries, disorder, or ionized impurity scattering, pointing to the possibility of further improvements.

Medical physics practice guideline 4.b: Development, implementation, use and maintenance of safety checklists.

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