Enhanced magnetic and thermoelectric properties in epitaxial polycrystalline SrRuO3 thin film

Transition metal oxide thin films show versatile electrical, magnetic, and thermal properties which can be tailored by deliberately introducing macroscopic grain boundaries via polycrystalline solids. In this study, we focus on the modification of the magnetic and thermal transport properties by fabricating single- and polycrystalline epitaxial SrRuO3 thin films using pulsed laser epitaxy. Using epitaxial stabilization technique with atomically flat polycrystalline SrTiO3 substrate, epitaxial polycrystalline SrRuO3 thin film with crystalline quality of each grain comparable to that of single-crystalline counterpart is realized. In particular, alleviated compressive strain near the grain boundaries due to coalescence is evidenced structurally, which induced enhancement of ferromagnetic ordering of the polycrystalline epitaxial thin film. The structural variations associated with the grain boundaries further reduce the thermal conductivity without deteriorating the electronic transport, and lead to enhanced thermoelectric efficiency in the epitaxial polycrystalline thin films, compared with their single-crystalline counterpart.Comment: 24 pages, 5 figure

Ultra‐high elastic strain energy storage in hybrid metal‐oxide infiltrated polymer nanocomposites

An understanding of the mechanical properties of materials at nanometer length scales, including a material’s ability to store and release elastic strain energy, is of great significance in the effective miniaturization of actuators, sensors and resonators for use in micro-/nano-electromechanical systems (MEMS/NEMS) as well as advanced development of artificial muscles for locomotion in soft robots. The measure of a material’s ability to store and release elastic strain energy, the modulus of resilience (R), is a crucial parameter in realizing such advanced mechanical actuation technologies. Typically, engineering a material system with a large R requires large increases in the material’s yield strength yet conservative increase in Young’s modulus, an engineering challenge as the two mechanical properties are strongly coupled; generally, strengthening methods results in considerable stiffening or increase in the Young’s modulus. Here, we present hybrid composite polymer nanopillars which achieve the highest specific R ever reported, by utilizing vapor-phase aluminum oxide infiltrations into lithographically patterned polymer resist SU-8. In-situ nanomechanical measurements reveal high, metallic-like yield strengths (~500 MPa) combined with a compliant, polymeric-like Young’s modulus (~7 GPa), a unique pairing never observed in known engineering materials. It is these exceptional elastic properties of our hybrid composite which allows for realization of R per density (Rs) values ~ 11200 J/kg, orders of magnitude greater than those in most engineering material systems. The high elastic energy storage/release capability of this material, as well as its compatibility with lithographic techniques, makes it an attractive candidate in the design of MEMS devices, which require an ultra-high elastic component for advanced actuation and sensor technologies. Furthermore, an opportunity for tunability of the elastic properties of the SU-8 polymeric material exists with this fabrication technique by varying the number of infiltration cycles or the organometallic precursor Please click Additional Files below to see the full abstract

Design for Sharing Emotional Touches during Phone Calls: A Quantitative Evaluation of Four Tactile Representations

Background As the importance of mobile phones as an emotional communication medium is growing, non-verbal behaviors such as facial expressions, touching behaviors and gestures ought to be considered to enhance phone conversations. Among various non-verbal signals, we focus on sharing specific touches that could be used for exchanging contextual and emotional cues. Along with this, to make the new phone conversation involving touching more natural, we consider maintaining natural audio conversation with phones by keeping the receiver on the ear and the transmitter on the mouth while holding the phone to the cheek. Methods In this paper, we focus on investigating ways to deliver four touches: pat, slap, tickle and kiss with sound and tactile feedback while holding the phone to the cheek as in typical phone calls. The interaction technique is called CheekTouch, and it is based on enabling users to share touches by representing finger gestures on one phone screen to the other party???s cheek using a vibrotactile display and sound stimulations. We asked the 30 students who participated to put the device on their cheek and wear earphones, and we provided them with 24 different stimulations. Results An evaluation was conducted to propose the most appropriate type of stimulation to deliver a pat, slap, tickle and kiss using CheekTouch. We showed that the best way to deliver a pat was to use a vibrotactile display combined with sound; however, a tickle was best delivered with only the vibrotactile display. A kiss and slap, on the other hand, were best delivered when there was only sound. Conclusions Considering the trends in sharing delicate emotions during phone-mediated communications, it is significant to investigate ways to convey touches during phone conversations beyond sharing visual emoticons. Here, we focused on findings ways to pat, slap, tickle and kiss by using existing phone technologies (vibrotactile motors and sound). Through the quantitative evaluation of those four touches, we discovered which stimulation type is best for delivering each of the touches. The results do not show whether those touches can deliver emotions, however, we believe CheekTouch and the findings from the evaluation can be used for sharing different types of non-verbal signals during audio-based phone conversations and enable further studies in the field of remote tactile interaction.clos

COVID-19 Perception, Knowledge, and Preventive Practice: Comparison between South Korea, Ethiopia, and Democratic Republic of Congo

In Africa, the first confirmed case of COVID-19 was reported in Egypt on February 14, 2020. Since then, the number of cases has continued to  increase with Ethiopia, the Democratic Republic of Congo (DRC), Nigeria, Sudan, Angola, Tanzania, Ghana, and Kenya identified as vulnerable  countries. The present study aimed to: 1) identify differences in trust level of COVID-19 diagnosis, recent healthcare utilization experiences, and COVID-19-related knowledge, information, and prevention practices in South Korea, Ethiopia, and DRC; and 2) identify factors influencing trust level in healthcare facilities regarding COVID-19 diagnosis. The present study was cross-sectional. The questionnaire survey was conducted between May 1–14, 2020 using Google forms, and 748 respondents were included in the final analysis. The data collected were analyzed using ANOVA, post - hoc test, and binary logistic regression analysis. South Korea showed higher rate of practice for COVID-19 prevention such as hand washing, mask wearing, and etc. than Ethiopia and DRC. The results showed significant differences with the trust level being 3.129 times higher in respondents from DRC than those from Ethiopia (aOR=3.129, 95% CI: [1.884-5.196], p<.000) and 29.137 times higher in respondents from South Korean than those from Ethiopia (aOR=29.137, 95% CI: [13.869-61.210], p<.000). Gender, age, number of family members, healthcare utilization experience, information, and practice were significant variables. Health education expansion for information and practice about COVID-19 in Ethiopia and DRC is necessary. Keywords: COVID-19, Pandemic, Ethiopia, DRC, South Korea, Online Survey En Afrique, le premier cas confirmé de COVID-19 a été signalé en Égypte le 14 février 2020. Depuis, le nombre de cas n'a cessé d'augmenter avec l'Éthiopie, la République démocratique du Congo (RDC), le Nigéria, le Soudan, l'Angola, La Tanzanie, le Ghana et le Kenya ont été identifiés comme pays vulnérables. La présente étude visait à: 1) identifier les différences de niveau de confiance dans le diagnostic du COVID-19, les expériences récentes d'utilisation des soins de santé et les connaissances, informations et pratiques de prévention liées au COVID-19 en Corée du Sud, en Éthiopie et en RDC; et 2) identifier les facteurs influençant le niveau de confiance dans les établissements de santé concernant le diagnostic du COVID-19. La présente étude était transversale. L'enquête par questionnaire a été menée du 1er au 14 mai 2020 à l'aide de formulaires Google, et 748 répondants ont été inclus dans l'analyse finale. Les données collectées ont été analysées en utilisant une analyse ANOVA, un test post-hoc et une analyse de régression logistique binaire. La Corée du Sud a montré un taux de pratique plus élevé pour la prévention du COVID-19, comme le lavage des mains, le port d'un masque, etc. que l'Éthiopie et la RDC. Les résultats ont montré des différences significatives, le niveau de confiance étant 3,129 fois plus élevé chez les répondants de RDC que chez ceux d'Éthiopie (aOR = 3,129, IC à 95%: [1,884-5,196], p <.000) et 29,137 fois plus élevé chez les répondants sud-coréens que ceux d'Éthiopie (aOR = 29,137, IC à 95%: [13,869-61,210], p <.000). Le sexe, l'âge, le nombre de membres de la famille, l'expérience d'utilisation des soins de santé, l'information et la pratique étaient des variables importantes. L'élargissement de l'éducation sanitaire pour l'information et la pratique du COVID-19 en Éthiopie et en RDC est nécessaire. Mots-clés: COVID-19, Pandémie, Éthiopie, RDC, Corée du Sud, Enquête en lign

Enhanced magnetic and thermoelectric properties in epitaxial polycrystalline SrRuO3 thin film

Transition metal oxide thin films show versatile electrical, magnetic, and thermal properties which can be tailored by deliberately introducing macroscopic grain boundaries via polycrystalline solids. In this study, we focus on the modification of the magnetic and thermal transport properties by fabricating single- and polycrystalline epitaxial SrRuO3 thin films using pulsed laser epitaxy. Using epitaxial stabilization technique with atomically flat polycrystalline SrTiO3 substrate, epitaxial polycrystalline SrRuO3 thin film with crystalline quality of each grain comparable to that of single-crystalline counterpart is realized. In particular, alleviated compressive strain near the grain boundaries due to coalescence is evidenced structurally, which induced enhancement of ferromagnetic ordering of the polycrystalline epitaxial thin film. The structural variations associated with the grain boundaries further reduce the thermal conductivity without deteriorating the electronic transport, and lead to enhanced thermoelectric efficiency in the epitaxial polycrystalline thin films, compared with their single-crystalline counterpart.Comment: 24 pages, 5 figure

Capnography for Assessing Nocturnal Hypoventilation and Predicting Compliance with Subsequent Noninvasive Ventilation in Patients with ALS

BACKGROUND: Patients with amyotrophic lateral sclerosis (ALS) suffer from hypoventilation, which can easily worsen during sleep. This study evaluated the efficacy of capnography monitoring in patients with ALS for assessing nocturnal hypoventilation and predicting good compliance with subsequent noninvasive ventilation (NIV) treatment. METHODS: Nocturnal monitoring and brief wake screening by capnography/pulse oximetry, functional scores, and other respiratory signs were assessed in 26 patients with ALS. Twenty-one of these patients were treated with NIV and had their treatment compliance evaluated. RESULTS: Nocturnal capnography values were reliable and strongly correlated with the patients' respiratory symptoms (R(2) = 0.211-0.305, p = 0.004-0.021). The duration of nocturnal hypercapnea obtained by capnography exhibited a significant predictive power for good compliance with subsequent NIV treatment, with an area-under-the-curve value of 0.846 (p = 0.018). In contrast, no significant predictive values for nocturnal pulse oximetry or functional scores for nocturnal hypoventilation were found. Brief waking supine capnography was also useful as a screening tool before routine nocturnal capnography monitoring. CONCLUSION: Capnography is an efficient tool for assessing nocturnal hypoventilation and predicting good compliance with subsequent NIV treatment of ALS patients, and may prove useful as an adjunctive tool for assessing the need for NIV treatment in these patients