Effects of adhesive thickness on global and local Mode-I interfacial fracture of bonded joints

AbstractThe interfacial fracture of adhesively bonded structures is a critical issue for the extensive applications to a variety of modern industries. In the recent two decades, cohesive zone models (CZMs) have been receiving intensive attentions for fracture problems of adhesively bonded joints. Numerous global tests have been conducted to measure the interfacial toughness of adhesive joints. Limited local tests have also been conducted to determine the interface traction-separation laws in adhesive joints. However, very few studies focused on the local test of effects of adhesive thickness on the interfacial traction-separation laws. Interfacial toughness and interfacial strength, as two critical parameters in an interfacial traction-separation law, have important effect on the fracture behaviors of bonded joints. In this work, the global and local tests are employed to investigate the effect of adhesive thickness on interfacial energy release rate, interfacial strength, and shapes of the interfacial traction-separation laws. Basically, the measured laws in this work reflect the equivalent and lumped interfacial fracture behaviors which include the cohesive fracture, damage and plasticity. The experimentally determined interfacial traction-separation laws may provide valuable baseline data for the parameter calibrations in numerical models. The current experimental results may also facilitate the understanding of adhesive thickness-dependent interface fracture of bonded joints

Association Between Serum Vitamin D Status and Uterine Leiomyomas: A Case-Control Study

OBJECTIVE: Uterine leiomyoma is a common gynecological condition that negatively affects women\u27s quality of life. Vitamin D plays an important role in tumor development and progression. However, clinical studies comparing serum vitamin D levels between women with and without uterine leiomyomas are limited and inconclusive. This study aimed to compare serum vitamin D levels in women with and without uterine leiomyomas. METHODS: This hospital-based case-control study included 150 women who visited a gynecological clinic. The cases included 75 women with uterine leiomyoma, whereas the controls included 75 age-and parity-matched participants without uterine leiomyoma. Serum vitamin D levels were measured in each participant and volumes of the uterine leiomyomas were determined using the water displacement method following myomectomy. The statistical significance was inferred at P\u3c0.05. RESULTS: The mean serum vitamin D level was 15.26±4.96 ng/mL and 22.45±6.93 ng/mL for the case and control groups, respectively. The difference was statistically significant (t-value -7.302 and P CONCLUSION: Women with uterine leiomyoma had lower vitamin D levels than women in the control group. Lower vitamin D levels were associated with larger fibroid masses. Therefore, vitamin D supplementation may reduce fibroid growth and development

Association between serum vitamin D status and uterine leiomyomas: a case-control study

Objective Uterine leiomyoma is a common gynecological condition that negatively affects women’s quality of life. Vitamin D plays an important role in tumor development and progression. However, clinical studies comparing serum vitamin D levels between women with and without uterine leiomyomas are limited and inconclusive. This study aimed to compare serum vitamin D levels in women with and without uterine leiomyomas. Methods This hospital-based case-control study included 150 women who visited a gynecological clinic. The cases included 75 women with uterine leiomyoma, whereas the controls included 75 age-and parity-matched participants without uterine leiomyoma. Serum vitamin D levels were measured in each participant and volumes of the uterine leiomyomas were determined using the water displacement method following myomectomy. The statistical significance was inferred at P<0.05. Results The mean serum vitamin D level was 15.26±4.96 ng/mL and 22.45±6.93 ng/mL for the case and control groups, respectively. The difference was statistically significant (t-value −7.302 and P<0.001). Within the fibroid group, nine (12.0%), 49 (65.33%), and 17 (22.67%) participants had vitamin D deficiency, insufficiency, and sufficiency, respectively; and in the control group, two (2.67%), 24 (45.33%), and 39 (52.0%) participants had vitamin D deficiency, insufficiency, and sufficiency, respectively. There was significant negative correlation between the fibroid volume and the serum vitamin D level (r=−0.591, P<0.001). Conclusion Women with uterine leiomyoma had lower vitamin D levels than women in the control group. Lower vitamin D levels were associated with larger fibroid masses. Therefore, vitamin D supplementation may reduce fibroid growth and development

Global phylogeography and ancient evolution of the widespread human gut virus crAssphage

Microbiomes are vast communities of microorganisms and viruses that populate all natural ecosystems. Viruses have been considered to be the most variable component of microbiomes, as supported by virome surveys and examples of high genomic mosaicism. However, recent evidence suggests that the human gut virome is remarkably stable compared with that of other environments. Here, we investigate the origin, evolution and epidemiology of crAssphage, a widespread human gut virus. Through a global collaboration, we obtained DNA sequences of crAssphage from more than one-third of the world's countries and showed that the phylogeography of crAssphage is locally clustered within countries, cities and individuals. We also found fully colinear crAssphage-like genomes in both Old-World and New-World primates, suggesting that the association of crAssphage with primates may be millions of years old. Finally, by exploiting a large cohort of more than 1,000 individuals, we tested whether crAssphage is associated with bacterial taxonomic groups of the gut microbiome, diverse human health parameters and a wide range of dietary factors. We identified strong correlations with different clades of bacteria that are related to Bacteroidetes and weak associations with several diet categories, but no significant association with health or disease. We conclude that crAssphage is a benign cosmopolitan virus that may have coevolved with the human lineage and is an integral part of the normal human gut virome

Global phylogeography and ancient evolution of the widespread human gut virus crAssphage

Microbiomes are vast communities of microorganisms and viruses that populate all natural ecosystems. Viruses have been considered to be the most variable component of microbiomes, as supported by virome surveys and examples of high genomic mosaicism. However, recent evidence suggests that the human gut virome is remarkably stable compared with that of other environments. Here, we investigate the origin, evolution and epidemiology of crAssphage, a widespread human gut virus. Through a global collaboration, we obtained DNA sequences of crAssphage from more than one-third of the world’s countries and showed that the phylogeography of crAssphage is locally clustered within countries, cities and individuals. We also found fully colinear crAssphage-like genomes in both Old-World and New-World primates, suggesting that the association of crAssphage with primates may be millions of years old. Finally, by exploiting a large cohort of more than 1,000 individuals, we tested whether crAssphage is associated with bacterial taxonomic groups of the gut microbiome, diverse human health parameters and a wide range of dietary factors. We identified strong correlations with different clades of bacteria that are related to Bacteroidetes and weak associations with several diet categories, but no significant association with health or disease. We conclude that crAssphage is a benign cosmopolitan virus that may have coevolved with the human lineage and is an integral part of the normal human gut virome

Influence of the church in select indigenious Niger Delta music

This study analyses the performance techniques, instrumentation and songs of selected indigenized songs in Niger Delta region of Nigeria that are being influenced by the church. The aim of the study is to archive and document most of the rich indigenous music to increase the scanty ethno-musicological literatures existing in this ethnic group. The paper explores qualitative methodology to analyse the data collected from selected churches in Niger Delta ethnic group. It employs the ethnomusicology theory by Titon(2021), as its theoretical framework. This theory defines ethnomusicology as the study of people making music in their ethnic groups. People make sounds that are recognised as music, and people also make “music” into a cultural domain. The study employs the descriptive and analytical methods. It reveals that modernity and development have great influence on Christian church music performance techniques bringing about varieties of indigenous church songs; as well as the changes we see in instrumentations, songs, dance steps and contexts of performance. The study concludes that God is too vast to be contained within any one race of musical performance, even one gender, language, environment, culture, or ethnicity; or even within and by our individual or communal musical or artistic preferences

A Thermoset Shape Memory Polymer-Based Syntactic Foam with Flame Retardancy and 3D Printability

Here we report a thermoset shape memory polymer-based syntactic foam inherently integrated with flame retardancy, good mechanical properties, excellent shape memory effect, and 3D printability. The syntactic foam is fabricated by incorporating a high-temperature shape memory polymer (HTSMP) as the matrix, with 40 vol % hollow glass microspheres (HGM) K20, K15, and K1 as fillers. Compressive behavior, strain-controlled programming followed by free recovery, stress recovery, and flame retardancy of these three syntactic foams were studied. Dynamic mechanical analysis and thermal characterization validate their high glass transition temperature ( = ∼250 °C) and excellent thermal stability. Our results suggest that the foam consisting of K20 HGM exhibits high compressive strength (81.8 MPa), high recovery stress (6.8 MPa), and excellent flame retardancy. Furthermore, this syntactic foam was used for three-dimensional (3D) printing by an extruder developed in our lab. Honeycomb, sinusoidal shapes, and free-standing helical spring were printed for demonstration. This high-temperature photopolymer-based syntactic foam integrated with high , flame retardancy, high recovery stress, and 3D printability can be beneficial in different sectors such as aerospace, construction, oil and gas, automotive, and electronic industries