1,394 research outputs found

    Biological system development for GraviSat: A new platform for studying photosynthesis and microalgae in space

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    Microalgae have great potential to be used as part of a regenerative life support system and to facilitate in-situ resource utilization (ISRU) on long-duration human space missions. Little is currently known, however, about microalgal responses to the space environment over long (months) or even short (hours to days) time scales. We describe here the development of biological support subsystems for a prototype “3U” (i.e., three conjoined 10-cm cubes) nanosatellite, called GraviSat, designed to experimentally elucidate the effects of space microgravity and the radiation environment on microalgae and other microorganisms. The GraviSat project comprises the co-development of biological handling-and-support technologies with implementation of integrated measurement hardware for photosynthetic efficiency and physiological activity in support of long-duration (3–12 months) space missions. It supports sample replication in a fully autonomous system that will grow and analyze microalgal cultures in 120μL wells around the circumference of a microfluidic polymer disc; the cultures will be launched while in stasis, then grown in orbit. The disc spins at different rotational velocities to generate a range of artificial gravity levels in space, from microgravity to multiples of Earth gravity. Development of the biological support technologies for GraviSat comprised the screening of more than twenty microalgal strains for various physical, metabolic and biochemical attributes that support prolonged growth in a microfluidic disc, as well as the capacity for reversible metabolic stasis. Hardware development included that necessary to facilitate accurate and precise measurements of physical parameters by optical methods (pulse amplitude modulated fluorometry) and electrochemical sensors (ion-sensitive microelectrodes). Nearly all microalgal strains were biocompatible with nanosatellite materials; however, microalgal growth was rapidly inhibited (~1 week) within sealed microwells that did not include dissolved bicarbonate due to CO2 starvation. Additionally, oxygen production by some microalgae resulted in bubble formation within the wells, which interfered with sensor measurements. Our research achieved prolonged growth periods (\u3e10months) without excess oxygen production using two microalgal strains, Chlorella vulgaris UTEX 29 and Dunaliella bardawil 30.861, by lowering light intensities (2–10μmol photons m−2s−1) and temperature (4–12˚C). Although the experiments described here were performed to develop the GraviSat platform, the results of this study should be useful for the incorporation of microalgae in other satellite payloads with low-volume microfluidic systems

    Toward real-time and efficient cardiovascular monitoring for COVID-19 patients by 5G-enabled wearable medical devices: a deep learning approach

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    Patients with deaths from COVID-19 often have co-morbid cardiovascular disease. Real-time cardiovascular disease monitoring based on wearable medical devices may effectively reduce COVID-19 mortality rates. However, due to technical limitations, there are three main issues. First, the traditional wireless communication technology for wearable medical devices is difficult to satisfy the real-time requirements fully. Second, current monitoring platforms lack efficient streaming data processing mechanisms to cope with the large amount of cardiovascular data generated in real time. Third, the diagnosis of the monitoring platform is usually manual, which is challenging to ensure that enough doctors online to provide a timely, efficient, and accurate diagnosis. To address these issues, this paper proposes a 5G-enabled real-time cardiovascular monitoring system for COVID-19 patients using deep learning. Firstly, we employ 5G to send and receive data from wearable medical devices. Secondly, Flink streaming data processing framework is applied to access electrocardiogram data. Finally, we use convolutional neural networks and long short-term memory networks model to obtain automatically predict the COVID-19 patient’s cardiovascular health. Theoretical analysis and experimental results show that our proposal can well solve the above issues and improve the prediction accuracy of cardiovascular disease to 99.29%

    Comportamento alimentar do peixe recifal Sargentinho (Abudefduf saxatilis) em Santa Catarina

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    TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Biológicas. Biologia.Estudos da ecologia alimentar de peixes recifais são essenciais para compreender o fluxo energético nestes ecossistemas. Diversos estudos abordam o comportamento alimentar das espécies, porém, são poucos os estudos que avaliam esse comportamento ao longo do dia. Visto isso, este estudo busca observar e quantificar o comportamento alimentar do peixe recifal Sargentinho (Abudefduf saxatilis) no litoral de Santa Catarina, Brasil. Foram realizados mergulhos livres e autônomos, nos quais empregou-se busca ativa por indivíduos de A. saxatilis. Utilizando o método de animal focal, um indivíduo era seguido de cada vez por um minuto ou até sua primeira mordida, quando era anotado em qual substrato o mesmo estava mordendo, seu comprimento total e o horário. Para verificar se [1] há diferenças no substrato de forrageio ao longo do dia; e se [2] há diferença no substrato de forrageio entre classes de tamanho, foram utilizados teste-G. Sete substratos foram utilizados pela espécie para forrageio, sendo a coluna d’água o predominante (79,7% dos indivíduos observados), seguido pelos substratos bentônicos: matriz algal epilítica (16,6%), Sargassum sp. (3,3%), alga calcária (0,22%), Palythoa sp. (0,12%) e desova de A. saxatilis (0,06%). As análises sugerem A. saxatilis prefere forragear na coluna d’água durante toda a manhã e no final da tarde, com maior intensidade antes do meio dia, enquanto no começo da tarde preferem o componente bentônico. Estas diferenças podem ser explicadas pelo comportamento oportunista da espécie, que o permite explorar diferentes substratos para forrageio. Também foi demonstrado que as classes de tamanho utilizam diferentes substratos de forrageio, indicando diferenças nas demandas energéticas ao longo de sua ontogenia. Por fim este trabalho revela a grande importância do comportamento alimentar na compreensão geral da ecologia alimentar para a espécie.Reef fish feeding ecology is essential for understating the energy flow of these ecosystems. Many studies approach feeding behaviour, although those approaching the variation of feeding behaviours during the day are scarce. This study aims to observe the feeding behaviour of the reef fish Sargeant major (Abudefduf saxatilis) on the coast of Santa Catarina state, Brazil. For this, free and SCUBA dives were conducted, in which active search for A. saxatilis was performed. Using the focal animal method, an individual was followed each time for one minute or until it’s first bite, when the bitten substrate, total length and time was recorded. To verify if [1] there are differences among the foraging substratum during the day; and if [2] there are differences among foraging substratum between different size classes, a G-test was used. Seven substrata were utilized, being the water column predominant (79,7% of observed individuals), followed by the benthic substrata: epilitic algal matrix (16,6%), Sargassum sp. (3,3%), calcareous algae (0,22%), Palythoa sp. (0,12%) and A. saxatilis eggs (0,06%). The analysis suggests that A. saxatilis prefer to forage on the water column during the morning and end of the evening, with a higher intensity of bites before midday, while at the beginning of the evening benthic substrata are preferred. These differences can be explained by the opportunistic behaviour of the species, that allows the exploration of different substrata. It was also demonstrated that individual size classes use different foraging substrata, indicating different energetic demands according to the species different ontogeny. Lastly, this study verified the important role of feeding behaviour in the general understanding of the species feeding ecology

    Improving Long-Term Adherence to Monitoring/Treatment in Underserved Asian Americans with Chronic Hepatitis B (CHB) through a Multicomponent Culturally Tailored Intervention: A Randomized Controlled Trial

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    Background: Although Asian Americans make up 6% of the U.S. population, they account for 58% of Americans with chronic hepatitis B (CHB). Yet, adherence to monitoring and antiviral treatment guidelines among Asian American CHB patients remains suboptimal. Methods: The purpose of this study was to evaluate the efficacy of a multicomponent intervention on adherence to CHB monitoring among Asian Americans with CHB. The intervention components included virtual patient education, patient navigation, and mobile health reminders delivered by bilingual community health educators. Chi-square test and t -test were used to compare demographic characteristics and two CHB measures: CHB clinical follow-up and CHB laboratory monitoring by the time of the 12-month follow-up assessment. A generalized linear mixed-effects model (GLMM) was fitted to assess the effectiveness of the intervention. Results: The study sample consisted of 358 Chinese and Vietnamese Americans living with CHB, including 181 in the intervention group and 177 in the control group. The intervention group had a significantly higher rate of CHB clinical follow- up (86.2%) and CHB laboratory monitoring (79.0%) than did the control group (54.2% and 45.2%, respectively). Results of the GLMM showed significant intervention effects on CHB clinical follow-up (odds ratio = 7.35, 95% confidence interval = 4.06–13.33) and CHB laboratory monitoring (odds ratio = 6.60, 95% confidence interval = 3.77–11.56) at the 12-month follow-up assessment. Conclusion: The multicomponent intervention was effective in improving adherence to CHB monitoring among Asian Americans. Additional implementation research is needed to better understand and apply effective interventions to other underserved populations

    Reducing Liver Cancer Risk through Dietary Change: Positive Results from a Community-Based Educational Initiative in Three Racial/Ethnic Groups

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    Dietary behaviors and alcohol consumption have been linked to liver disease and liver cancer. So far, most of the liver cancer awareness campaigns and behavioral interventions have focused on preventive behaviors such as screening and vaccination uptake, while few incorporated dietary aspects of liver cancer prevention. We implemented a community-based education initiative for liver cancer prevention among the African, Asian, and Hispanic populations within the Greater Philadelphia and metropolitan New York City areas. Data from the baseline and the 6-month follow-up surveys were used for the assessment of changes in dietary behaviors and alcohol consumption among participants. In total, we recruited 578 participants through community-/faith-based organizations to participate in the educational workshops. The study sample included 344 participants who completed both baseline and follow-up survey. The Hispanic subgroup was the only one that saw an overall significant change in dietary behaviors, with the Mediterranean dietary score increasing significantly from 30.000 at baseline survey to 31.187 at 6-month follow-up assessment ( p \u3c 0.05), indicating a trend towards healthier dietary habit. In the African Americans participants, the consumption scores of fruits and poultry increased significantly, while vegetables and red meats decreased. In Asian Americans, the consumption of non-refined cereals, red meats, and dairy products decreased. Alcohol consumption decreased significantly among Hispanics while it did not change significantly among the other two communities. This community-based educational initiative generated different impacts in the three populations, further highlighting the needs for more targeted, culturally tailored efforts in health promotion among these underprivileged communities

    ROS release by PPARβ/δ-null fibroblasts reduces tumor load through epithelial antioxidant response.

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    Tumor stroma has an active role in the initiation, growth, and propagation of many tumor types by secreting growth factors and modulating redox status of the microenvironment. Although PPARβ/δ in fibroblasts was shown to modulate oxidative stress in the wound microenvironment, there has been no evidence of a similar effect in the tumor stroma. Here, we present evidence of oxidative stress modulation by intestinal stromal PPARβ/δ, using a FSPCre-Pparb/d <sup>-/-</sup> mouse model and validated it with immortalized cell lines. The FSPCre-Pparb/d <sup>-/-</sup> mice developed fewer intestinal polyps and survived longer when compared with Pparb/d <sup>fl/fl</sup> mice. The pre-treatment of FSPCre-Pparb/d <sup>-/-</sup> and Pparb/d <sup>fl/fl</sup> with antioxidant N-acetyl-cysteine prior DSS-induced tumorigenesis resulted in lower tumor load. Gene expression analyses implicated an altered oxidative stress processes. Indeed, the FSPCre-Pparb/d <sup>-/-</sup> intestinal tumors have reduced oxidative stress than Pparb/d <sup>fl/fl</sup> tumors. Similarly, the colorectal cancer cells and human colon epithelial cells also experienced lower oxidative stress when co-cultured with fibroblasts depleted of PPARβ/δ expression. Therefore, our results establish a role for fibroblast PPARβ/δ in epithelial-mesenchymal communication for ROS homeostasis

    Berry phase, hyperorbits, and the Hofstadter spectrum: semiclassical dynamics in magnetic Bloch bands

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    We have derived a new set of semiclassical equations for electrons in magnetic Bloch bands. The velocity and energy of magnetic Bloch electrons are found to be modified by the Berry phase and magnetization. This semiclassical approach is used to study general electron transport in a DC or AC electric field. We also find a close connection between the cyclotron orbits in magnetic Bloch bands and the energy subbands in the Hofstadter spectrum. Based on this formalism, the pattern of band splitting, the distribution of Hall conduct- ivities, and the positions of energy subbands in the Hofstadter spectrum can be understood in a simple and unified picture.Comment: 26 pages, Revtex, 6 figures included, submitted to Phys.Rev.

    Factors Associated with Hepatitis B Medication Adherence and Persistence among Underserved Chinese and Vietnamese Americans

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    Background: Hepatitis B virus (HBV) infection disproportionately affects Asian Amer- icans in the United States, while this population faces low adherence to HBV treatment. Using the information–motivation–behavioral skills model (IMB), the study aims to examine medication adherence and persistence among Chinese and Vietnamese people with HBV. Methodology: Study participants were recruited between March 2019 and March 2020 and were enrolled through multiple recruitment approaches in the Greater Philadelphia Area and New York City. The study is an assess- ment of the baseline data on medication adherence, HBV-related knowledge, motivation of HBV med- ication treatment, self-efficacy about HBV medication treatment, and socioeconomic status. Results: Among 165 participants, 77.6% were Chinese and 22.4% were Vietnamese Americans. HBV-related knowledge/information, motivation, and self-efficacy were all positively associated with having medium/high medication adherence. Multilevel mixed-effects generalized linear regression revealed that living more than 10 years in the U.S. (OR = 4.24; p = 0.028) and greater information–knowledge about HBV (OR = 1.46; p = 0.004) were statistically associated with higher odds of medium/high medication adherence. Moreover, greater HBV-related knowledge/information ( OR = 1.49; p = 0.023) and greater motivation towards HBV treatment adherence (OR = 1.10; p = 0.036) were both associated with a higher likelihood of medication persistence. Conclusion: Our findings provided significant im- plications in designing behavioral interventions focused on self-efficacy, information, and motivation to promote better medication adherence among Asian Americans living with HBV
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