Articles de revues : « PHEME »

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West, Donna E. « The Operation of Peirce’s Pheme in Narrative Contexts ». Contemporary Pragmatism 19, n^o 4 (4 août 2022) : 331–49. http://dx.doi.org/10.1163/18758185-bja10051.

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Abstract Peirce’s Pheme directs interpretation of narratives via a “series of surprises” (ep2:154). The indexical and iconic elements inherent in Phemes are particularly potent in forcing attention and depicting relevant events. Index intrudes upon interpreters’ consciousness to notice the unexpected consequence; but icons exploit vividness. As imperatives, Phemes compel particular behaviors (1906: ms295). When narratives are portrayed in pictures, interpreters remember happenings in which Phemes feature surprising percepts, evoking an attentional response, and securing a confluence of events in memory. Findings from children’s narrations demonstrate that events represented by Phemes are more often included in children’s retellings, because surprising images command active participation. This viewpoint impels listeners to build episodes, ascribing meanings across events, and proposing rationale for novel outcomes.

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Williams, Michael A. « Gnosticism and the New Testament. Pheme Perkins ». Journal of Religion 75, n^o 4 (octobre 1995) : 555–57. http://dx.doi.org/10.1086/489690.

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Martin, Troy W. « Peter : Apostle for the Whole Church. Pheme Perkins ». Journal of Religion 82, n^o 1 (janvier 2002) : 107–8. http://dx.doi.org/10.1086/491003.

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Hernandez-Mendoza, Maria, Ana Aguilera, Irvin Dongo, Jose Cornejo-Lupa et Yudith Cardinale. « Credibility Analysis on Twitter Considering Topic Detection ». Applied Sciences 12, n^o 18 (9 septembre 2022) : 9081. http://dx.doi.org/10.3390/app12189081.

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Twitter is one of the most popular sources of information available on the internet. Thus, many studies have proposed tools and models to analyze the credibility of the information shared. The credibility analysis on Twitter is generally supported by measures that consider the text, the user, and the social impact of text and user. More recently, identifying the topic of tweets is becoming an interesting aspect for many applications that analyze Twitter as a source of information, for example, to detect trends, to filter or classify tweets, to identify fake news, or even to measure a tweet’s credibility. In most of these cases, the hashtags represent important elements to consider to identify the topics. In a previous work, we presented a credibility model based on text, user, and social credibility measures, and a framework called T-CREo, implemented as an extension of Google Chrome. In this paper, we propose an extension of our previous credibility model by integrating the detection of the topic in the tweet and calculating the topic credibility measure by considering hashtags. To do so, we evaluate and compare different topic detection algorithms, to finally integrate in our framework T-CREo, the one with better results. To evaluate the performance improvement of our extended credibility model and show the impact of hashtags, we performed experiments in the context of fake news detection using the PHEME dataset. Results demonstrate an improvement in our extended credibility model with respect to the original one, with up to 3.04% F1 score when applying our approach to the whole PHEME dataset and up to 9.60% F1 score when only considering tweets that contain hashtags from PHEME dataset, demonstrating the impact of hashtags in the topic detection process.

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Mba, Jean Romuald, Djamila Zouheira, Hadidjatou Dairou, Fanta S. A. Yadang, Nfor Njini Gael, Lawrence Ayong, Jules-Roger Kuiate et Gabriel A. Agbor. « In Vitro Antioxidant, Anti-Inflammatory, and Digestive Enzymes Inhibition Activities of Hydro-Ethanolic Leaf and Bark Extracts of Psychotria densinervia (K. Krause) Verdc ». Advances in Pharmacological and Pharmaceutical Sciences 2022 (6 mai 2022) : 1–12. http://dx.doi.org/10.1155/2022/8459943.

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Psychotria densinervia hydro-ethanolic leaf extract (PHELE) and bark extract (PHEBE) were evaluated for antioxidant, anti-inflammatory, and inhibition of digestive enzymes activities. The antioxidant activity was characterized by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), and total flavonoid content (TFC) assays. The anti-inflammatory activity was characterized by protein denaturation and antiproteinase tests, while the inhibition of the enzymes was assessed using α-amylase, α-glucosidase, lipase, and cholesterol esterase activities. PHELE presented low ( p < 0.001 ) IC50 (59.09 ± 5.97 μg/ml) for DPPH compared with ascorbic acid (71.78 ± 6.37 μg/ml) and PHEBE (115.40 ± 1.21 μg/ml). The IC50 of PHELE (262.4 ± 4.46 μg/ml) and PHEBE (354.2 ± 1.97 μg/ml) was higher ( p < 0.001 ) than that of catechin (33.48 ± 2.02 μg/ml) for ABTS. PHELE had high ( p < 0.001 ) FRAP (341.73 ± 21.70 mg CE/g) than PHEBE (150.30 ± 0.32 mg CE/g). PHELE presented ( p < 0.001 ) high TPC (270.05 ± 7.53 mg CE/g) and TFC (23.43 ± 0.032 mg CE/g) than PHEBE (TPC: 138.89 ± 0.91 and TFC: 20.06 ± 0.032 mg CE/g). PHELE showed antiprotein denaturation with IC50 (257.0 ± 7.51 μg/ml) ( p < 0.001 ) and antiproteinase activity (74.37 ± 1.10 μg/ml) lower than PHEBE (316.1 ± 6.02 μg/ml and 177.6 ± 0.50 μg/ml), respectively. Orlistat inhibited lipase ( p < 0.001 ) activity with IC50 (37.11 ± 4.39 μg/ml) lower than PHELE and PHEBE (50.57 ± 2.89 μg/ml and 62.88 ± 1.74 μg/ml, respectively). PHELE inhibited cholesterol esterase with IC50 (34.75 ± 3.87 μg/ml) lower than orlistat (54.61 ± 2.56) and PHEBE (80.14 ± 1.71 μg/ml). PHELE inhibited α-amylase IC50 (6.07 ± 4.05 μg/ml) lower than PHEBE (19.69 ± 6.27 μg/ml) and acarbose (20.01 ± 2.84 μg/ml). Acarbose inhibited α-glucosidase ( p < 0.001 ) activity with IC50 (4.11 ± 3.47 μg/ml) lower than PHELE (24.41 ± 2.84 μg/ml) and PHEBE (38.81 ± 2.46 μg/ml). PHELE presented better antioxidant, anti-inflammatory, and enzyme inhibition activity than PHEBE.

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Kiran, Sirra Kanthi, M. Shashi et K. B. Madhuri. « Multi-stage Transfer Learning for Fake News Detection Using AWD-LSTM Network ». International Journal of Information Technology and Computer Science 14, n^o 5 (8 octobre 2022) : 58–69. http://dx.doi.org/10.5815/ijitcs.2022.05.05.

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In the recent decades, the automatic veracity verification of rumors is essential, since online social media platforms allow users to post news item or express opinion towards a circulating piece of information without much restriction. The intention of fake news is to make the readers believe in inaccurate information, where the detection of fake news by using content is a difficult task. So, the auxiliary information: user profile, social engagement of the users, and other user’s comments are useful in the detection of fake news. In this manuscript, a novel multi-stage transfer learning approach is introduced for an effective fake news detection, where it utilizes user’s comments as auxiliary information to detect whether the given tweet is true or false. The stances of the response tweets contain opinions on news/rumors are often used for verifying the veracity of the circulating information. In order to devastate the effects of the specific rumors at the earliest, the multi-stage transfer learning approach automatically predict veracity of rumors jointly with the stances of their response tweets. The proposed multi-stage transfer learning is an inductive transfer learning variation that is used to forecast the stance of responses, then to identify fake news. The proposed model’s effectiveness is evaluated on the two-benchmark datasets: semEval-2017 task 8 and PHEME. The proposed model outperformed the existing approaches by obtaining a classification accuracy of 64.30% and 65.30%, an F-measure of 65.95% and 63.90% on semEval-2017 task 8, and PHEME on event-wise datasets.

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Qian, Xiaohong. « A Tentative Study on English Euphemism ». Journal of Contemporary Educational Research 4, n^o 2 (19 février 2020) : 9–12. http://dx.doi.org/10.26689/jcer.v4i2.1010.

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The word “euphemism” comes from the Greek, eu--means “good”, and –pheme-, “speech” or “saying”, and together it means literally “to speak with good words or in a pleasant manner”. Euphemism, as a cultural phenomenon as well as a linguistic concept, has attracted people’s attention for a long time. It has long been a topic of much interest. In every society there are certain things that are supposed to be unspeakable. Many words make someone embarrassed, unhappy, dislike or fear when used in communication. If we express the meaning directly, we will make such impression which is vulgar, frivolous, and impolite. In order to avoid the embarrassment or ease the sting of harsh words, man has created euphemisms.

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Ningtias, Anggitha, Rosidah et Yuandani. « Poguntano Herba Extract Immunostimulant Activities (Picriafel-terraeLour). in Immunosupression Rats Infected by Staphylococcus aureus Against Total Leukocytes and Differential Leukocytes ». Indonesian Journal of Pharmaceutical and Clinical Research 4, n^o 1 (28 mai 2021) : 39–46. http://dx.doi.org/10.32734/idjpcr.v4i1.5378.

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Poguntano (Picriafel-terraeLour.) is a medicinal plant in North Sumatra that has been used in traditional medicine to treat degenerative diseases.Poguntano extract contains flavonoid compounds that have the potential to be developed into immunomodulators. This study showed the immunostimulant activity of poguntano herb n-hexane extract (PHNHE), poguntano herb ethyl acetate extract (PHEAE) and poguntano herb ethanol extract (PHEE) in immunosuppressed rats infected with Staphylococcus aureus. The evidence of poguntano herb as an immunomodulator was carried out by testing total leukocytes and differential leukocytes. Poguntano herb n-hexane extract (PHNHE) can not increase the total and differential leukocytes; Poguntano herb ethyl acetate extract (PHEAE) and poguntano herb ethanol extract (PHEE) can increase the total and differential leukocytes in immunosuppressed rats induced by Staphylococcus aureus.

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Rogerson, J. W. « Resurrection. New Testament Witness and Contemporary Reflection. By Pheme Perkins. London, Geoffrey Chapman, 1984. Pp. 504. £19.95. » Scottish Journal of Theology 39, n^o 2 (mai 1986) : 243–44. http://dx.doi.org/10.1017/s0036930600030581.

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Suthanthiradevi, P., et S. Karthika. « Veracity assessment by single and multi-source identification algorithms during the crisis ». Journal of Intelligent & ; Fuzzy Systems 42, n^o 3 (2 février 2022) : 1421–31. http://dx.doi.org/10.3233/jifs-210540.

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Social networks have become a popular communication tool for information sharing. Twitter offers access to data and provides a significant opportunity to analyze data. During pandemics, Twitter becomes a big source for the dispersal of unverified information. In social media, it is difficult to find the sources of rumors. To tackle this problem the authors have developed a hybrid rumor centrality algorithm for rumor source detection in social networks. The authors propose an S-RSI algorithm for identifying a single rumor centre and an M-RSI algorithm for identifying the propagations of multiple rumor centres in the thread of conversation. The proposed rumor centrality algorithm efficiently predicts the rumor disseminating possibilities in a conversation tree with the aid of graph theoretical approach. The authors have evaluated the performance of the algorithms on the PHEME dataset containing seven real-time event conversational trees based on the tweet messages. The results show that the proposed is best suitable in finding the rumor source centre with a high probability in social media during a crisis.

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Khoo, Ling Min Serena, Hai Leong Chieu, Zhong Qian et Jing Jiang. « Interpretable Rumor Detection in Microblogs by Attending to User Interactions ». Proceedings of the AAAI Conference on Artificial Intelligence 34, n^o 05 (3 avril 2020) : 8783–90. http://dx.doi.org/10.1609/aaai.v34i05.6405.

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We address rumor detection by learning to differentiate between the community's response to real and fake claims in microblogs. Existing state-of-the-art models are based on tree models that model conversational trees. However, in social media, a user posting a reply might be replying to the entire thread rather than to a specific user. We propose a post-level attention model (PLAN) to model long distance interactions between tweets with the multi-head attention mechanism in a transformer network. We investigated variants of this model: (1) a structure aware self-attention model (StA-PLAN) that incorporates tree structure information in the transformer network, and (2) a hierarchical token and post-level attention model (StA-HiTPLAN) that learns a sentence representation with token-level self-attention. To the best of our knowledge, we are the first to evaluate our models on two rumor detection data sets: the PHEME data set as well as the Twitter15 and Twitter16 data sets. We show that our best models outperform current state-of-the-art models for both data sets. Moreover, the attention mechanism allows us to explain rumor detection predictions at both token-level and post-level.

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Singhal, Shilpa. « Rumor Detection on Twitter ». International Journal for Research in Applied Science and Engineering Technology 9, n^o 8 (31 août 2021) : 2543–46. http://dx.doi.org/10.22214/ijraset.2021.37799.

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Abstract: Social media interaction such as news spreading around the network is a great source of information nowadays. From one’s perspective, its negligible exertion, straightforward access, and quick dispersing of information that lead people to look out and eat up news from internet-based life. Twitter is among the most well-known ongoing news sources that ends up a standout amongst the most dominant news spreading mediums. It is known to cause extensive harm by spreading bits of fake news among the people. Online clients are normally vulnerable and are reliable on web-based networking media as their source of information without checking the veracity of the information being spread. This research contributes to develops a system for detection of rumors about real- world events that propagate on Twitter and to design a prediction algorithm that will train the machine to predict whether the given data is information or a rumor. The work finds all the useful features of a Tweet. The dataset used is the pheme dataset of known Rumors and Non Rumors. Afterwards, we make a comparison between various known Machine learning algorithms such as Decision tree, SVM, Random Tree.

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West, Donna E. « The element of surprise in Peirce’s double consciousness paradigm ». Semiotica 2021, n^o 243 (20 octobre 2021) : 11–47. http://dx.doi.org/10.1515/sem-2021-0122.

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Abstract This account will demonstrate that the element of surprise is a fundamental device in establishing double consciousness regimes; it further shows how such dialogic paradigms foster abductive inferences by filtering out irrelevant percepts/antecedents. The account sets up Peirce’s Pheme to be the primary device which shocks interpreters’ sensibilities (CP 8.266, 1903) – starting them on a course to question conflicting principles between ego and non-ego (CP 5.53, 1903: CP 8.266). The natural disposition of surprise to instantaneously deliver insight into which antecedents are relevant to vital, anomalous consequences demonstrates its indispensability in generating logical and semiotic advances. For Peirce, vividness, as an element of surprise in Secondness, is largely responsible for the nuts and bolts of how surprise facilitates logic; its means to activate searches for plausible antecedents makes vividness the prime candidate. The success of vividness at turning the mind of interpreters to new ways of explaining the consequence largely hinges upon the external properties of the unexpected consequence – not merely objects’ instantaneity, but their striking characteristics, as well. Even though vividness is external (MS 645, 1909; cf. Atkins 2018: 198), it produces internal responses, in the form of a war against feelings (CP 8.330, 1904). In this way, double consciousness paradigms are initiated, which, in turn, call for hypothesis generation.

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Gidwani, Manya, et Ashwini Rao. « Comparative Analysis of Rumour Detection on Social Media Using Different Classifiers ». Informatics and Automation 22, n^o 4 (6 juillet 2023) : 777–94. http://dx.doi.org/10.15622/ia.22.4.3.

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As the number of users on social media rise, information creation and circulation increase day after day on a massive basis. People can share their ideas and opinions on these platforms. A social media microblogging site such as Facebook or Twitter is the favoured medium for debating any important event, and information is shared immediately. It causes rumours to spread quickly and circulates inaccurate information, making people uneasy. Thus, it is essential to evaluate and confirm the level of veracity of such information. Because of the complexities of the text, automated detection of rumours in their early phases is challenging. This research employs various NLP techniques to extract information from tweets and then applies various machine learning models to determine whether the information is a rumour. The classification is performed using three classifiers such as SVC (Support Vector Classifier), Gradient Boosting, and Naive Bayes classifiers for five different events from the PHEME dataset. Some drawbacks include limited handling of imbalanced data, difficulty capturing complex linguistic patterns, lack of interpretability, difficulty handling large feature spaces, and insensitivity to word order and context by using the above classifiers. The stacking approach is used to overcome the above drawbacks in which the output of combined classifiers is an ensemble with LSTM. The performance of the models has been analyzed. The experimental findings reveal that the ensemble model obtained efficient outcomes compared to other classifiers, with an accuracy of 93.59%.

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O'Reilly, Matthew P. « First Corinthians. By Pheme Perkins. Paideia Commentaries on the New Testament. Grand Rapids, MI : Baker Academic, 2012. Pp. xiv + 238. Paper, $30.00. » Religious Studies Review 39, n^o 4 (décembre 2013) : 269–70. http://dx.doi.org/10.1111/rsr.12084_24.

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Lu, Heng-yang, Chenyou Fan, Xiaoning Song et Wei Fang. « A novel few-shot learning based multi-modality fusion model for COVID-19 rumor detection from online social media ». PeerJ Computer Science 7 (20 août 2021) : e688. http://dx.doi.org/10.7717/peerj-cs.688.

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Background Rumor detection is a popular research topic in natural language processing and data mining. Since the outbreak of COVID-19, related rumors have been widely posted and spread on online social media, which have seriously affected people’s daily lives, national economy, social stability, etc. It is both theoretically and practically essential to detect and refute COVID-19 rumors fast and effectively. As COVID-19 was an emergent event that was outbreaking drastically, the related rumor instances were very scarce and distinct at its early stage. This makes the detection task a typical few-shot learning problem. However, traditional rumor detection techniques focused on detecting existed events with enough training instances, so that they fail to detect emergent events such as COVID-19. Therefore, developing a new few-shot rumor detection framework has become critical and emergent to prevent outbreaking rumors at early stages. Methods This article focuses on few-shot rumor detection, especially for detecting COVID-19 rumors from Sina Weibo with only a minimal number of labeled instances. We contribute a Sina Weibo COVID-19 rumor dataset for few-shot rumor detection and propose a few-shot learning-based multi-modality fusion model for few-shot rumor detection. A full microblog consists of the source post and corresponding comments, which are considered as two modalities and fused with the meta-learning methods. Results Experiments of few-shot rumor detection on the collected Weibo dataset and the PHEME public dataset have shown significant improvement and generality of the proposed model.

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West, Donna E. « Index as scaffold to logical and final interpretants : Compulsive urges and modal submissions ». Semiotica 2019, n^o 228 (7 mai 2019) : 333–53. http://dx.doi.org/10.1515/sem-2018-0085.

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AbstractThis inquiry capitalizes on the relational character of Peirce’s index. Its evolution from object finder in the physical world, to enhancer of communication between minds, to modal/perspectival coordinator is examined. Its relational character organizes events into episodes, and obviates perspectival alterations in dialogic reasoning. This shift demonstrates Peirce’s last word regarding Index: a sign intrinsically dialogic, whose interpretants increase levels of consciousness, and advance communicational interaction by commanding self/others to believe/act in novel ways.Its power to coordinate specific, vivid images provides index with the means to suggest novel propositions, assertions, and arguments. Peirce memorializes this relational role by characterizing index as Dicisign, and afterward as Pheme (1904, CP 8.334–8.339; 1906, MS 295: 26; 1908, EP 2: 489–490). As truncated Argument, Index provides the catalyst for interpreters to determine the meaning of interpretants be they Energetic, Logical or Final. Its non-symbolic character provides interpreters the impetus to utilize inferencing powers to attach meanings, thus expanding kinds of interpretants. Index constitutes the most diverse semiotic tool for interpreters – it traces subtle deontic, epistemic, and logical shifts. In situating and resituating events in time, place, and participatedness, Index aptly measures actual and potential shifts in affect, attention, location, credibility, and the like.Ultimately, index integrates the logical with the phenomenological and the empirical with the semiotic – when it deploys relational operators to trace event templates and to predict participant’s perspectives. As such, interpreters restructure thought and action and recommend sound courses of action for diverse event participants.

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Akin, David Gentry. « 1–2 Peter and Jude. Wisdom Commentary 56. By Pheme Perkins, Eloise Rosenblatt, and Patricia McDonald. Collegeville, MN : Liturgical Press, 2022. xxxviii + 322 pages. $49.95. » Horizons 50, n^o 1 (juin 2023) : 224–26. http://dx.doi.org/10.1017/hor.2023.23.

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Azer, Marina, Mohamed Taha, Hala H. Zayed et Mahmoud Gadallah. « Credibility Detection on Twitter News Using Machine Learning Approach ». International Journal of Intelligent Systems and Applications 13, n^o 3 (8 juin 2021) : 1–10. http://dx.doi.org/10.5815/ijisa.2021.03.01.

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Social media presence is a crucial portion of our life. It is considered one of the most important sources of information than traditional sources. Twitter has become one of the prevalent social sites for exchanging viewpoints and feelings. This work proposes a supervised machine learning system for discovering false news. One of the credibility detection problems is finding new features that are most predictive to better performance classifiers. Both features depending on new content, and features based on the user are used. The features' importance is examined, and their impact on the performance. The reasons for choosing the final feature set using the k-best method are explained. Seven supervised machine learning classifiers are used. They are Naïve Bayes (NB), Support vector machine (SVM), Knearest neighbors (KNN), Logistic Regression (LR), Random Forest (RF), Maximum entropy (ME), and conditional random forest (CRF). Training and testing models were conducted using the Pheme dataset. The feature's analysis is introduced and compared to the features depending on the content, as the decisive factors in determining the validity. Random forest shows the highest performance while using user-based features only and using a mixture of both types of features; features depending on content and the features based on the user, accuracy (82.2 %) in using user-based features only. We achieved the highest results by using both types of features, utilizing random forest classifier accuracy(83.4%). In contrast, logistic regression was the best as to using features that are based on contents. Performance is measured by different measurements accuracy, precision, recall, and F1_score. We compared our feature set with other studies' features and the impact of our new features. We found that our conclusions exhibit high enhancement concerning discovering and verifying the false news regarding the discovery and verification of false news, comparing it to the current results of how it is developed.

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Hooper, N. M., R. J. Hesp et S. Tieku. « Metabolism of aspartame by human and pig intestinal microvillar peptidases ». Biochemical Journal 298, n^o 3 (15 mars 1994) : 635–39. http://dx.doi.org/10.1042/bj2980635.

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The artificial sweetener aspartame (N-L-alpha-aspartyl-L-phenyl-alanine-1-methyl ester; Nutrasweet), its decomposition product alpha Asp-Phe and the related peptide alpha Asp-PheNH2 were rapidly hydrolysed by microvillar membranes prepared from human duodenum, jejunum and ileum, and from pig duodenum and kidney. The metabolism of aspartame by the human and pig intestinal microvillar membrane preparations was inhibited significantly (> 78%) by amastatin or 1,10-phenanthroline, and partially (> 38%) by actinonin or bestatin, and was activated 2.9-4.5-fold by CaCl2. The inhibition by amastatin and 1,10-phenanthroline, and the activation by CaCl2 are characteristic of the cell-surface ectoenzyme aminopeptidase A (EC 3.4.11.7) and a purified preparation of this enzyme hydrolysed aspartame with a Km of 0.25 mM and a Vmax of 126 mumol/min per mg. A purified preparation of aminopeptidase W (EC 3.4.11.16) also hydrolysed aspartame but with a Km of 4.96 mM and a Vmax of 110 mumol/min per mg. However, rentiapril, an inhibitor of aminopeptidase W, caused only slight inhibition (maximally 19%) of the hydrolysis of aspartame by the microvillar membrane preparations. Similar patterns of inhibition and kinetic parameters were observed for alpha Asp-Phe and alpha Asp-PheNH2. Two other decomposition products of aspartame, beta Asp-PheMe and cyclo-Asp-Phe, were essentially resistant to hydrolysis by both the human and pig intestinal microvillar membrane preparations and the purified preparations of aminopeptidases A and W. Although the relatively selective inhibitor of aminopeptidase N (EC 3.4.11.2), actinonin, partially inhibited the metabolism of aspartame, alpha Asp-Phe and alpha Asp-PheNH2 by the human and pig intestinal microvillar membrane preparations, these peptides were not hydrolysed by a purified preparation of aminopeptidase N. Membrane dipeptidase (EC 3.4.13.19) only hydrolysed the unblocked dipeptide, alpha Asp-Phe, but the selective inhibitor of this enzyme, cilastatin, did not block the metabolism of alpha Asp-Phe by the microvillar membrane preparations.

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Ko, Young Gwang, Kwan Han Yoon, Jin Ho Jang, Masayuki Yamato, Akihiko Kikuchi, Teruo Okano, Inn Kyu Kang et Oh Hyeong Kwon. « Rapid Cell Sheet Recovery by Successive Grafting of PHEMA and PIPAAm onto TCPS Dish Surfaces ». Key Engineering Materials 342-343 (juillet 2007) : 245–48. http://dx.doi.org/10.4028/www.scientific.net/kem.342-343.245.

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Rapid recovery of cell sheets is considered important to maintain the biological function and viability of recovered cell sheets. To accelerate required culture substrate hydrophilic/ hydrophobic structural changes in response to culture temperature alteration, poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(N-isopropylacrylamide) (PIPAAm) were grafted successively onto tissue culture polystyrene (TCPS) dishes by electron beam irradiation. Analysis by attenuated total reflection-Fourier transform infrared revealed that PHEMA and PIPAAm were successfully grafted to surfaces of TCPS dish. PIPAAm-PHEMA-grafted TCPS (PIPAAm-PHEMA-TCPS) dishes were compared with PIPAAm-grafted TCPS dishes for cell sheet detachment experiments. Approximately 75 min was required to completely detach cell sheets from PIPAAm-TCPS dish, compared to only 13 min to detach cell sheets from PIPAAm-PHEMA-TCPS dish, which is successively grafted with PHEMA and PIPAAm. PHEMA is a well-known as a high hygroscopic polymer. In the case of PIPAAm-PHEMA-TCPS dish, PHEMA layer acted as a water pool to accelerate the hydration of PIPAAm layer due to the effective and simultaneous water supply to PIPAAm layer, resulting in rapid hydration of grafted PIPAAm molecules and detachment of cell sheet compare to PIPAAm-TCPS dish without PHEMA layer.

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Yantaboot, K., S. Maensiri, Paveena Khansawai et Sittipong Amnuaypanich. « Surface Modification of Alumina Nano-Particles by UV-Induced Grafting Polymerization of 2-Hydroxyethyl Methacrylate ». Advanced Materials Research 93-94 (janvier 2010) : 95–98. http://dx.doi.org/10.4028/www.scientific.net/amr.93-94.95.

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Alumina nano-particles was grafted with poly(2-hydroxyethyl methacrylate) (PHEMA) utilizing the sequential method; that is, the alumina surface was first rendered with initiator, benzophenone, by UV-irradiation followed by the grafting polymerization of HEMA on the surface which was initiated thermally and propagated via the free-radical polymerization. FT-IR spectroscopy confirmed the successful grafting of PHEMA onto the alumina surface. Determined by thermalgravimetry (TG), the amount of benzophenone on the alumina surface was found to increase with the UV-irradiation time; however upon grafting of PHEMA, the amount of grafted-PHEMA was the same irrespective of the reaction time. The glass transition temperature (Tg) of grafted-PHEMA on alumina particles was approximately 93 °C that is higher than that of PHEMA which has Tg around 85 °C. This indicates the more restricted movement of grafted-PHEMA compared with the ungrafted-PHEMA.

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Bhuyan, Pranjit Kr. « Synthesis of Poly2-Hydroxyethyl Methacrylate Photo Initiated by N,N-Diethyldithiocarbamato-(1,2)-Propanediol ». Advanced Materials Research 1169 (18 mars 2022) : 7–13. http://dx.doi.org/10.4028/p-50fwm0.

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Photopolymerisation of 2-Hydroxyethyl methacrylate (HEMA) through the use of N,N-Diethyldithiocarbamato-(1,2)-propanediol (DCPD) was studied. The photoinitiator DCPD was synthesized from sodium N,N-Diethyldithiocarbamate (NaSR) and 3-chloro-1,2-propanediol. For the photochemical decomposition of the C – S bond, UV light at 254 nm is used. The role of the monomer concentration, reaction time and DCPD to HEMA mol ratio on the conversion of HEMA to PHEMA were studied in this paper. It was found that percentage conversion of HEMA increased both with the rise in concentration of monomer and reaction time. Further, living radical nature of the poly2-Hydroxyethyl methacrylate (PHEMA) was ascertained by the photo block copolymerization of methyl methacrylate (MMA) with PHEMA to form PHEMA-b-PMMA. The PHEMA and PHEMA-b-PMMA were characterized by FTIR, 1H-NMR, Thermogravimetry.

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Yoshida, Hidekazu, Shinichi Itsuno et Koichi Ito. « Syntheses and interfacial characterization of graft copolymers from styrene and 2-hydroxyethyl methacrylate that comprise either trunks or branches ». Canadian Journal of Chemistry 73, n^o 11 (1 novembre 1995) : 1757–64. http://dx.doi.org/10.1139/v95-216.

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Polystyrene (PS) and poly(2-hydroxyethyl methacrylate) (PHEMA) macromonomers with either p-vinylbenzyl or methacrylate end groups were prepared by living anionic polymerizations of styrene and 2-(trimethylsilyloxy)ethyl methacrylate, respectively, followed by appropriate end-capping. They were radically copolymerized with 2-hydroxyethyl methacrylate and styrene, respectively, to afford PS-g-PHEMA and PHEMA-g-PS, having PS trunks with PHEMA branches or the reverse architecture. 1H NMR spectra of the graft copolymers in deuterated methanol showed their micelle formation with PS and PHEMA chains as the core and the shell, respectively. In chloroform the reverse micelles were observed. Contact angle measurements of water on the graft copolymer films revealed that PS chains were generally dominant on the free surface. The films either cast from methanol or after immersion into water, however, were apparently wettable, indicating dominant PHEMA chains on the surface. Keywords: styrene, 2-hydroxyethyl methacrylate, graft copolymer, micelle formation, wettability.

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Emelyanov, Nikolay, et Jean-Eudes Arlot. « Astrometric results PHEMU-1985 and PHEMU-1991 ». Planetary and Space Science 187 (août 2020) : 104946. http://dx.doi.org/10.1016/j.pss.2020.104946.

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Makarova, E. B., M. A. Korch, F. A. Fadeyev, D. G. Bliznets, A. V. Bugayova, T. F. Shklyar, A. P. Safronov, K. A. Nokhrin et F. A. Blyakhman. « Testing of the pHEMA hydrogel as an implantation material for replacement of osteochondral defects in animals ». Russian Journal of Transplantology and Artificial Organs 24, n^o 2 (25 avril 2022) : 71–82. http://dx.doi.org/10.15825/1995-1191-2022-2-71-82.

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Objective: to evaluate the features of reparative chondrogenesis and osteogenesis in animal experiments with the implantation of porous poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel into osteochondral defects. Materials and methods. Cylindrical pHEMA implants (5 mm in diameter) were synthesized by radical polymerization. The implants were subjected to light microscopy and mechanical tests to characterize the structure and viscoelastic properties of the material. In experimental group #1, four pHEMA specimens were implanted into formed defects in the distal femoral epiphysis of rabbits. In experimental group #2, allogeneic chondrocytes were applied to the surface of four specimens before implantation. In the control series, four defects were not replaced with implants. Tissue regeneration was investigated by morphological and morphometric methods 30 days after operation. Results. The pHEMA implants were heterogeneous specimens with irregularly shaped pores – up to 30 × 10 μm at the surface and 300 × 120 μm inside. With >10% static compressive stress, the Young’s modulus was 54.7 kPa. For dynamic stress, increased frequency of compression-relaxation cycles from 0.01 Hz to 20.0 Hz led to increased storage modulus from 20 kPa to 38 kPa on average, and increased loss modulus from 2 kPa to 10 kPa. Indicators of semi-quantitative assessment of local inflammatory response to pHEMA implantation had the following values in points: pHEMA, 4.7 ± 0.3; pHEMA with allogeneic chondrocytes, 6.0 ± 1.0; control, 4.3 ± 0.3. The ratio of connective, bone, and cartilage tissues proper in the regenerates had the following respective values: pHEMA, 79%, 20%, 1%; pHEMA with chondrocytes, 82%, 16%, 2%; control, 9%, 74%, 17%. Conclusion. In a short-term experiment, pHEMA implants did not trigger a pronounced inflammatory response in the surrounding tissues and can be classified as biocompatible materials. However, the tested implants had low conductivity with respect to bone and cartilage cells, which can be improved by stabilizing the pore size and increasing the rigidity when synthesizing the material.

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Yin, Jun. « Fabrication of a Modified Polyethersulfone Membrane with Anti-Fouling and Self-Cleaning Properties from SiO2-g-PHEMA NPs for Application in Oil/Water Separation ». Polymers 14, n^o 11 (27 mai 2022) : 2169. http://dx.doi.org/10.3390/polym14112169.

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To prepare anti-fouling and self-cleaning membrane material, a physical blending modification combined with surface grafting modification has been carried out; first, poly (2-hydroxyethyl methacrylate) grafted silica nanoparticles (SiO2-g-PHEMA NPs) were synthesized using surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) and used as a blending modifier to fabricate a polyethersulfone (PES)/SiO2-g-PHEMA organic–inorganic membrane by the phase-inversion method. During the membrane formation process, hydrophobic PES segments coagulated immediately to form a membrane matrix, and the hydrophilic SiO2-g-PHEMA NPs migrated spontaneously to the membrane surface in order to reduce interfacial energy, which enhanced the hydrophilicity and anti-fouling properties of the PES/SiO2-g-PHEMA membrane. Importantly, the membrane surface contained abundant PHEMA segments, which provided active sites for further surface functionalization. Subsequently, the carboxyl-terminated fluorocarbon surfactant (fPEG-COOH) composed of hydrophilic polyethyleneglycol segments and low-surface-energy perfluorinated alkyl segments was synthesized via the esterification of fPEG with succinic anhydride. Lastly, the PES/SiO2-g-PHEMA/fPEG membrane was prepared by grafting fPEG-COOH onto surface of the PES/SiO2-g-PHEMA. Thus, a versatile membrane surface with both fouling-resistant and fouling-release properties was acquired. The PES/SiO2-g-PHEMA/fPEG membrane has a large oil–water flux (239.93 L·m−2·h−1), almost 21 times that of PES blank membrane and 2.8 times of the PES/SiO2-g-PHEMA membrane. Compared with the unmodified PES membrane, the flux recovery ratio increased from 45.75% to 90.52%, while the total flux decline ratio decreased drastically from 82.70% to 13.79%, exhibiting outstanding anti-fouling and self-cleaning properties. Moreover, the grafted fPEG segments on the membrane surface show excellent stability due to the presence of stable chemical bonds. The grafted segments remain at the surface of the membrane even after a long shaking treatment. This suggests that this PES/SiO2-g-PHEMA/fPEG membrane material has potential for application in oil/water separation.

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He, Jingwei, Sufyan Garoushi, Eija Säilynoja, Pekka Vallittu et Lippo Lassila. « Surface Integrity of Dimethacrylate Composite Resins with Low Shrinkage Comonomers ». Materials 14, n^o 7 (26 mars 2021) : 1614. http://dx.doi.org/10.3390/ma14071614.

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The goal of current research was to investigate the influence of adding low shrinkage “Phene” like comonomers hexaethylene glycol bis(carbamate-isoproply-α-methylstyrene) (HE-Phene) and triethylene glycol bis(carbamate-isoproply-α-methylstyrene) (TE-Phene) on the surface and color characteristics of composite resin. A range of weight fractions (0, 10, 20, 30, 40 wt.%) of HE/TE-Phene monomers were mixed with bisphenol A glycidyl methacrylate (GMA)/triethylene glycol dimethacrylate (TEGDMA) monomer. Experimental composite resins were made by mixing 71 wt.% of silica fillers to 29 wt.% of the resin matrix. A Vickers indenter and glossmeter were used for testing surface hardness (SH) and gloss (SG) at 60°. A chewing-simulator was used to evaluate the surface wear after 15,000 cycles. Color change (∆E) and translucency parameter (TP) were measured using a spectrophotometer. Data showed that HE/TE-Phene monomer had no negative impact (p > 0.05) on surface gloss, wear, color change and translucency of experimental composite resins. Surface hardness was in a reducing direction with the increas in HE/TE-Phene weight fraction (p < 0.05). The study results suggested that incorporating HE/TE-Phene monomers up to 30 wt.% with Bis-GMA/TEGDMA resin did not negatively influence the surface integrity of composite resins except for SH.

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Dixit, Vivek, Erhan Piskin, Marika Arthur, Adil Denizli, Suleyman A. Tuncel, Emir Denkbas et Gary Gitnick. « Hepatocyte Immobilization on Phema Microcarriers and its Biologically Modified Forms ». Cell Transplantation 1, n^o 6 (novembre 1992) : 391–99. http://dx.doi.org/10.1177/096368979200100603.

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Polyhydroxyethylmethacrylate (PHEMA) based microcarriers with different bulk structures were prepared by a phase inversion polymerization technique. PHEMA surfaces were further modified chemically by glow-discharge treatment, and biologically by covalent attachment of fibrinogen and collagen. Hepatocytes were isolated from young male Wistar rats using an in situ portal vein collagenase perfusion technique. Freshly isolated hepatocytes were seeded at 6 × 105 cells/mL and microcarrier concentration was 10 g/L. Stationary microcarrier cultures were carried out in standard (nontissue culture) polystyrene petri dishes in a humidified 5% CO2 incubator at 37 ± 0.5°C. Cell attachment was followed by light microscopy by taking samples from the culture medium every 30 min. Urea and protein syntheses by microcarrier-attached hepatocytes were determined by standard techniques. Nonswellable (highly cross-linked) hydrophilic PHEMA microcarriers did not support cell attachment and viability. However, swellable (low cross-linked) PHEMA microcarriers (pretreated in FBS) allowed high attachment and cell spreading. PHEMA microcarriers treated in dimethylaminoethylmethacrylate (DMAEMA) glow-discharge plasma also improved the cell attachment characteristics of the PHEMA microcarriers. The highest attachment efficiencies (immobilization yields) were observed with the biologically modified PHEMA microcarriers, especially modified with fibronectin. Metabolic activity, as estimated by urea and protein syntheses, was also higher in these microcarriers.

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Zeng, Ren Chang, Jiang Cheng, Shou Ping Xu, Qin Liu, Xiu Fang Wen et Pi Hui Pi. « Preparation of Antimicrobial PHEMA-g-PCBMAE Hydrogels with Improved Mechanical Properties ». Applied Mechanics and Materials 576 (juin 2014) : 49–53. http://dx.doi.org/10.4028/www.scientific.net/amm.576.49.

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A series of poly (hydroxyethyl methacrylate)-g-polycarboxybetaine methacrylate ester (PHEMA-g-PCBMAE) hydrogels were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of crosslinker. Then differential scanning calorimetry (DSC) was used to characterize PHEMA-g-PCBMAE hydrogels. The compression stresses of these hydrogels were investigated to evaluate the mechanical properties. The mechanical study suggested that PHEMA-g-PCBMAE hydrogels presented improved mechanical strengths comparing with polycarboxybetaine methacrylate ester (PCBMAE) hydrogel. Besides, the antimicrobial properties of PHEMA-g-PCBMAE hydrogels also estimated by usingStaphylococcus aureusas a model bacterial.

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Bakshi, Ajay, Omar Fisher, Taner Dagci, B. Timothy Himes, Itzhak Fischer et Anthony Lowman. « Mechanically engineered hydrogel scaffolds for axonal growth and angiogenesis after transplantation in spinal cord injury ». Journal of Neurosurgery : Spine 1, n^o 3 (octobre 2004) : 322–29. http://dx.doi.org/10.3171/spi.2004.1.3.0322.

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Object. Spinal cord injury (SCI) is a complex pathological entity, the treatment of which requires a multipronged approach. One way to integrate different therapeutic strategies for SCI is to develop implantable scaffolds that can deliver therapies in a synergistic manner. Many investigators have developed implantable “bridges,” but an important property of such scaffolds—that is, mechanical compatibility with host tissues—has been neglected. In this study, the authors evaluated the results of implanting a mechanically matched hydrogel-based scaffold to treat SCI. Methods. A nonbiodegradable hydrogel, poly(2-hydroxyethylmethacrylate) (PHEMA), was engineered using thermally initiated free radical solution polymerization. Two groups of 12 adult Sprague—Dawley rats underwent partial cervical hemisection injury followed by implantation of either PHEMA or PHEMA soaked in 1 µg of brain-derived neurotrophic factor (BDNF). Four rats from each group were killed 1, 2, or 4 weeks after induction of the injury. Immunofluorescence staining was performed to determine the presence of scarring, cellular inflammatory responses, gliosis, angiogenesis, and axonal growth in and around the implanted scaffolds. Conclusions. The implanted PHEMA with 85% water content had a compressive modulus of 3 to 4 kPa, which matched the spinal cord. Implanted PHEMA elicited modest cellular inflammatory responses that disappeared by 4 weeks and minimal scarring was noted around the matrix. Considerable angiogenesis was observed in PHEMA, and PHEMA soaked in BDNF promoted axonal penetration into the gel. The authors conclude that mechanically engineered PHEMA is well accepted by host tissues and might be used as a platform for sustained drug delivery to promote axonal growth and functional recovery after SCI.

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Jung, Young Jae, Jae Chang Kim, Sangwon Ko et Jungkyu K. Lee. « Biochip Performances of Agarose, Poly(Oligo(Ethylene Glycol) Methacrylate), and Poly(2-Hydroxyethyl Methacrylate) Film on Glass Surfaces ». Journal of Nanoscience and Nanotechnology 20, n^o 8 (1 août 2020) : 5138–41. http://dx.doi.org/10.1166/jnn.2020.17826.

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We demonstrate the biochip efficacies of three different polymer films (agarose, poly(oligo(ethylene glycol) methacrylate) (pOEGMA), and poly(2-hydroxyethyl metacharylate) (pHEMA) on microscopic glass surfaces. As a result, the non-biofouling performances increased in this order: agarose < pOEGMA < pHEMA, and the binding capabilities increased in this order: pHEMA < pOEGMA < agarose.

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Ohura, Takeshi, Yusaku Tsutaki et Masato Sakaguchi. « Novel Synthesis of Cellulose-Based Diblock Copolymer of Poly(hydroxyethyl methacrylate) by Mechanochemical Reaction ». Scientific World Journal 2014 (2014) : 1–4. http://dx.doi.org/10.1155/2014/127506.

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The mechanical fracture of polymer produces polymeric free radical chain-ends, by which liner block copolymers have been synthesized. A diblock copolymer of microcrystalline cellulose (MCC) and poly 2-hydroxyethyl methacrylate (pHEMA) was produced by the mechanochemical polymerization under vacuum and room temperature. The fraction of pHEMA in MCC-block-pHEMA produced by the mechanochemical polymerization increased up to 21 mol% with increasing fracture time (~6 h). Then, the tacticities of HEMA sequences in MCC-block-pHEMA varied according to the reaction time. In the process of mechanochemical polymerization, cellulose could play the role of a radical polymerization initiator capable of controlling stereoregularity.

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Lee, Bor-Shiunn, Yu-Jia Chen, Ta-Chin Wei, Tien-Li Ma et Che-Chen Chang. « Comparison of Antibacterial Adhesion When Salivary Pellicle Is Coated on Both Poly(2-hydroxyethyl-methacrylate)- and Polyethylene-glycol-methacrylate-grafted Poly(methyl methacrylate) ». International Journal of Molecular Sciences 19, n^o 9 (14 septembre 2018) : 2764. http://dx.doi.org/10.3390/ijms19092764.

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Although poly(2-hydroxyethyl methacrylate) (pHEMA) and polyethylene glycol methacrylate (PEGMA) have been demonstrated to inhibit bacterial adhesion, no study has compared antibacterial adhesion when salivary pellicle is coated on polymethyl methacrylate (PMMA) grafted with pHEMA and on PMMA grafted with PEGMA. In this study, PMMA discs were fabricated from a commercial orthodontic acrylic resin system (Ortho-Jet). Attenuated total reflection-Fourier transform infrared spectra taken before and after grafting confirmed that pHEMA and PEGMA were successfully grafted on PMMA. Contact angle measurements revealed PMMA-pHEMA to be the most hydrophilic, followed by PMMA-PEGMA, and then by PMMA. Zeta potential analysis revealed the most negative surface charges on PMMA-PEGMA, followed by PMMA-pHEMA, and then by PMMA. Confocal laser scanning microscopy showed green fluorescence in the background, indicating images that influenced the accuracy of the quantification of live bacteria. Both the optical density value measured at 600 nm and single plate-serial dilution spotting showed that pHEMA was more effective than PEGMA against Escherichia coli and Streptococcus mutans, although the difference was not significant. Therefore, the grafting of pHEMA and PEGMA separately on PMMA is effective against bacterial adhesion, even after the grafted PMMA were coated with salivary pellicle. Surface hydrophilicity, bactericidality, and Coulomb repulsion between the negatively charged bacteria and the grafted surface contributed to the effectiveness.

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Raharjanti, Natalia Widiasih, et Adhitya Sigit Ramadianto. « Validity and Reliability od Postgraduate Hospital Educational Environment Measure - Bahasa Indonesia Version ». Jurnal Pendidikan Kedokteran Indonesia : The Indonesian Journal of Medical Education 5, n^o 3 (28 novembre 2016) : 157. http://dx.doi.org/10.22146/jpki.25375.

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Background: Educational environment is an essential factor influencing performance of medical residents, and unsupportive educational environment is associated with considerable harmful impacts. The Postgraduate Hospital Educational Environment Measure (PHEEM) is a self-administered questionnaire designed to measure residents’ perception of their educational environment. This study aims to establish the validity and reliability of PHEEM - Bahasa Indonesia version. Methods: The original PHEEM is translated and modified through an expert panel discussion. Construct validity is measured by corrected item-total correlation. Internal consistency reliability is measured by Cronbach’s alpha. Sample was taken from neurology and radiology residents. Results: The first validation trial was done on 44 neurology residents while the second trial was done in 35 radiology residents. Almost all item scores are correlated with the total score with r > 0,3. Cronbach’s alpha of PHEEM is 0,89 and 0,91 in the first and second trial, respectively.Conclusion: This is the first PHEEM validation study in Indonesia; changes to the instrument were made to maintain face and content validity. While the sample size is small and not selected randomly, PHEEM - Bahasa Indonesia version has acceptable validity and reliability to be used in research and evaluation of residency programs.

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Zare, Mina, Ashkan Bigham, Mohamad Zare, Hongrong Luo, Erfan Rezvani Ghomi et Seeram Ramakrishna. « pHEMA : An Overview for Biomedical Applications ». International Journal of Molecular Sciences 22, n^o 12 (15 juin 2021) : 6376. http://dx.doi.org/10.3390/ijms22126376.

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Poly(2-hydroxyethyl methacrylate) (pHEMA) as a biomaterial with excellent biocompatibility and cytocompatibility elicits a minimal immunological response from host tissue making it desirable for different biomedical applications. This article seeks to provide an in-depth overview of the properties and biomedical applications of pHEMA for bone tissue regeneration, wound healing, cancer therapy (stimuli and non-stimuli responsive systems), and ophthalmic applications (contact lenses and ocular drug delivery). As this polymer has been widely applied in ophthalmic applications, a specific consideration has been devoted to this field. Pure pHEMA does not possess antimicrobial properties and the site where the biomedical device is employed may be susceptible to microbial infections. Therefore, antimicrobial strategies such as the use of silver nanoparticles, antibiotics, and antimicrobial agents can be utilized to protect against infections. Therefore, the antimicrobial strategies besides the drug delivery applications of pHEMA were covered. With continuous research and advancement in science and technology, the outlook of pHEMA is promising as it will most certainly be utilized in more biomedical applications in the near future. The aim of this review was to bring together state-of-the-art research on pHEMA and their applications.

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Jubadi, W. M., F. Packeer et M. Missous. « Optimization of Empirical Modelling of Advanced Highly Strained In0.7Ga0.3As/In0.52Al0.48As pHEMTs for Low Noise Amplifier ». International Journal of Electrical and Computer Engineering (IJECE) 7, n^o 6 (1 décembre 2017) : 3002. http://dx.doi.org/10.11591/ijece.v7i6.pp3002-3009.

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<span>An optimized empirical modelling for a 0.25µm gate length of highly strained channel of an InP-based pseudomorphic high electron mobility transistor (pHEMT) using InGaAs–InAlAs material systems is presented. An accurate procedure for extraction is described and tested using the pHEMT measured dataset of I-V characteristics and related multi-bias s-parameters over 20GHz frequency range. The extraction of linear and nonlinear parameters from the small signal and large signal pHEMT equivalent model are performed in ADS. The optimized DC and S-parameter model for the pHEMT device provides a basis for active device selection in the MMIC low noise amplifier circuit designs.</span>

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Deng, Jun, Honghao Zheng et Changyou Gao. « Influence of protein adsorption on the cellular uptake of AuNPs conjugated with chiral oligomers ». Materials Chemistry Frontiers 1, n^o 3 (2017) : 542–49. http://dx.doi.org/10.1039/c6qm00163g.

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Gough, Jenny, Marilyn Bullen et Susan Donath. « PHEEM ‘Downunder’ ». Medical Teacher 32, n^o 2 (janvier 2010) : 161–63. http://dx.doi.org/10.3109/01421590903509036.

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Passos, M. F., D. R. C. Dias, G. N. T. Bastos, A. L. Jardini, A. C. B. Benatti, C. G. B. T. Dias et R. Maciel Filho. « pHEMA hydrogels ». Journal of Thermal Analysis and Calorimetry 125, n^o 1 (23 février 2016) : 361–68. http://dx.doi.org/10.1007/s10973-016-5329-6.

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Hashem, Mohamed A., Noura A. Abd-Allah, Essam A. Mahmoud, Shimaa A. Amer et Mohamed Alkafafy. « A Preliminary Study on the Effect of Psyllium Husk Ethanolic Extract on Hyperlipidemia, Hyperglycemia, and Oxidative Stress Induced by Triton X-100 Injection in Rats ». Biology 10, n^o 4 (16 avril 2021) : 335. http://dx.doi.org/10.3390/biology10040335.

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The aim of this study is to assess the efficiency of psyllium husk ethanolic extract (PHEE) on Triton X-100 induced hyperlipidemic rats by studying the changes in hepatic and pancreatic function and histopathology. Forty male albino rats (bodyweight 175–188 g) were grouped randomly into four sets with ten rats. The experimental groups included: (1) control group (CON); (2) Triton X-100 induced hyperlipidemic group—rats were intraperitoneally injected with a single dose of Triton X-100 (100 mg/kg body weight) on the 21st day of Trial onset; (3) PHEE group—PHEE was orally administered (100 mg/kg body weight dissolved in 1 mL of distilled water) by gastric tube from the first day of the experiment until the fortieth day, once daily, (PHEE); (4) PHEE +Triton group, which received PHEE orally with the induction of hyperlipidemia. Treating hyperlipidemic rats with PHEE showed a decrease in the total serum lipids, triglyceride (TG), total cholesterol (TC), atherogenic index (AI), and malondialdehyde (MDA) with an increase in superoxide dismutase (SOD) and catalase (CAT) activities. PHEE administration alleviated the negative impact of Triton on the serum levels of glucose, insulin, glycated hemoglobin (HbA1c), homeostatic model assessment for insulin resistance (HOMA IR index), leptin hormone, Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Gamma-Glutamyl Transferase (GGT) and proteinogram. The Triton-induced hyperlipidemic rats showed extensive histopathological changes in the liver and pancreas, which were alleviated with PHEE administration. It could be concluded that PHEE has potent effects against hyperlipidemia, hyperglycemia, and oxidative stress due to its biologically active constituents detected by GC-MS analysis. This study’s findings may help develop a novel trial against the effects of hyperlipidemia in the future.

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Jiang, Liu, Huaming Qian, Gang Chen, Chunyan Li, Guangjun Yan, Yanling Luo, Peng Liu et Yashao Chen. « Fabrication of micropatterns on polypropylene films via plasma pretreatment combined with UV-initiated graft polymerization ». Journal of Biomaterials Applications 31, n^o 10 (mai 2017) : 1346–57. http://dx.doi.org/10.1177/0885328217707100.

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In this study, micropatterns on polypropylene films were fabricated via plasma pretreatment and UV-initiated graft polymerization. Firstly, radio-frequency plasma, which does not significantly influence bulk attributes of substrates due to limited penetration depth, was utilized to activate polypropylene films. Then, different sizes of micropatterns of poly(hydroxyethyl methacrylate) (PHEMA) were fabricated on the polypropylene films via UV-initiated graft polymerization of hydroxyethyl methacrylate by using photo-masks. Scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and contact angle (CA) were employed to characterize changes of pristine polypropylene films and modified ones in surface morphology, roughness, hydrophilicity, free energy and the surface chemical composition. All of these confirmed the successful grafting of different sizes of PHEMA micropatterns on the polypropylene surface. Furthermore, the influence of PHEMA micropatterns on cell proliferation and cytotoxicity was evaluated in vitro. Analysis of cell behaviour indicated that PHEMA micropatterns of the appropriate size can promote cellular adhesion and proliferation, and the PHEMA-micropatterned polypropylene films had good biocompatibility. The approach presented here provides an alternative to synthesize on the surface of polypropylene films’ micropatterns with the aim of using them in a diverse array of applications.

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Sandoval-García, Karina, Abraham G. Alvarado-Mendoza, Eulogio Orozco-Guareño, María A. Olea-Rodríguez, Leonardo R. Cajero-Zul et Sergio M. Nuño-Donlucas. « Synthesis and Evaluation of Antifungal and Antibacterial Abilities of Carbon Nanotubes Grafted to Poly(2-hydroxyethyl methacrylate) Nanocomposites ». Polymers 15, n^o 18 (5 septembre 2023) : 3657. http://dx.doi.org/10.3390/polym15183657.

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Developing nanomaterials with the capacity to restrict the growth of bacteria and fungus is of current interest. In this study, nanocomposites of poly(2-hydroxyethyl methacrylate) (PHEMA) and carbon nanotubes (CNTs) functionalized with primary amine, hydroxyl, and carboxyl groups were prepared and characterized. An analysis by Fourier-transform infrared (FT-IR) spectroscopy showed that PHEMA chains were grafted to the functionalized CNTs. X-ray photoelectron spectroscopy suggested that the grafting reaction was viable. The morphology of the prepared nanocomposites studied by field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) showed significant changes with respect to the observed for pure PHEMA. The thermal behavior of the nanocomposites studied by differential scanning calorimetry (DSC) revealed that the functionalized CNTs strongly affect the mobility of the PHEMA chains. Tests carried out by thermogravimetric analysis (TGA) were used to calculate the degree of grafting of the PHEMA chains. The ability of the prepared nanocomposites to inhibit the growth of the fungus Candida albicans and the bacteria Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli was evaluated. A reduced antifungal and antibacterial capacity of the prepared nanocomposites was determined.

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Kong, Tao, Jing Lin, Lin Ye, Ai-ying Zhang et Zeng-guo Feng. « Synthesis of water soluble polyrotaxanes by end-capping polypseudo-rotaxanes of γ-CDs with PHEMA-PPO-PEO-PPO-PHEMA using ATRP of MPC ». Polymer Chemistry 6, n^o 32 (2015) : 5832–37. http://dx.doi.org/10.1039/c5py00674k.

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A twice ATRP protocol is developed for the preparation of water soluble single-chain stranded polyrotaxanes by end-capping polypseudorotaxanes formed from γ-CDs with PHEMA-PPO-PEO-PPO-PHEMA using PMPC as a bulky stopper.

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Протасов, Д. Ю., Д. В. Гуляев, А. К. Бакаров, А. И. Торопов, Е. В. Ерофеев et К. С. Журавлев. « Увеличение насыщенной скорости дрейфа электронов в pHEMT-гетероструктурах с донорно-акцепторным легированием ». Письма в журнал технической физики 44, n^o 6 (2018) : 77. http://dx.doi.org/10.21883/pjtf.2018.06.45770.17098.

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AbstractField dependences of the electron-drift velocity in typical pseudomorphic high-electron-mobility transistor (pHEMT) heteroepitaxial structures (HESs) and in those with donor–acceptor doped (DApHEMT) heterostructures with quantum-well (QW) depth increased by 0.8–0.9 eV with the aid of acceptor layers have been studied by a pulsed technique. It is established that the saturated electron-drift velocity in DA-pHEMT-HESs is 1.2–1.3 times greater than that in the usual pHEMT-HESs. The electroluminescence (EL) spectra of DA-pHEMT-HESs do not contain emission bands related to the recombination in widebandgap layers (QW barriers). The EL intensity in these HESs is not saturated with increasing electric field. This is indicative of a suppressed real-space transfer of hot electrons from QW to barrier layers, which accounts for the observed increase in the saturated electron-drift velocity.

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Wu, Zhao Xi, Gui Cui Fu et Han Tian Gu. « Electro-Thermal Effect Analysis on GaAs PHEMT Based on Physical Model ». Advanced Materials Research 842 (novembre 2013) : 192–95. http://dx.doi.org/10.4028/www.scientific.net/amr.842.192.

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Considering physical mechanisms, an electro-thermal effect model of GaAs pseudomorphic high electron mobility transistor (PHEMT) was proposed. The model included PAD capacitances, intrinsic elements and extrinsic elements, which represented the relationship of performance parameters to physical structure and temperature. By using this model, the effects of temperature to devices performance parameters could be analyzed, and the device's structure and materials' parameters could be optimized. A typical GaAs PHEMT was simulated in the EDA software. Thus, DC I-V characteristics and small-signal S parameters of PHEMT under varied temperatures could be given.

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Fang, Sheng, Meiyan Wang, Jingjing Liu, Bingwen Li et Jing-yao Liu. « Theoretical study on the reaction mechanism of “ligandless” Ni-catalyzed hydrodesulfurization of aryl sulfide ». RSC Advances 7, n^o 81 (2017) : 51475–84. http://dx.doi.org/10.1039/c7ra10755b.

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The reaction mechanism of Ni(COD)₂ catalyzed hydrodesulfurization of aryl sulfide PhSMe with HSiMe₃ has been predicted to have two competitive reaction pathways, with or without PhSMe spectator ligand, by using density functional theory methods.

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Zhao, San Ping, Hai Ling Xi, Qi Wang et Yan Jun Zuo. « Nucleophilic/Oxidizing Degradation of Paraoxon and Thioanisole Using NH₃ Modified Aqueous H₂O₂ Solution ». Applied Mechanics and Materials 675-677 (octobre 2014) : 75–81. http://dx.doi.org/10.4028/www.scientific.net/amm.675-677.75.

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Degradation of paraoxon and thioanisole (PhSMe) were studied using NH3modified H2O2solution as decontaminant. Degradation rates of paraoxon depend exponentially on pH of the modified solution. Nucleophilic substitution mediated by HOO-is the major degradation mechanism and at least two orders of magnitude faster than hydrolysis. Proton catalytic oxidation and solvent-aided oxidation contribute differently to the primary oxidation of PhSMe (PhSMe→PhS(O)Me), and the apparent kinetic constants (kap) of the primary oxidation show a three-stage profile with pH of the NH3-modified H2O2solution. Secondary oxidation of PhSMe (PhS(O) Me→PhS(O)2Me) is much slower than the primary oxidation in the modified H2O2solution, and the yield of PhS(O)2Me depended exponentially on pH too. The best pH range for the NH3modified H2O2solution as a broad-spectrum decontaminant is at 9.5-10.0 since a balance of nucleophilic/oxidizing decontamination reactivity could be achieved.

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Ong, Andrew Ming-Liang, Warren Weng-Seng Fong, Adrian Kwok-Wai Chan, Ghee-Chee Phua et Chee-Kian Tham. « Using the Postgraduate Hospital Educational Environment Measure to Identify Areas for Improvement in a Singaporean Residency Program ». Journal of Graduate Medical Education 11, n^o 4s (1 août 2019) : 73–78. http://dx.doi.org/10.4300/jgme-d-19-00234.

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ABSTRACT Background Attributes of the clinical learning environment (CLE) are a measure of quality in postgraduate medical education, and assessing the CLE is a component of the New Accreditation System being introduced in Singapore by the Accreditation Council for Graduate Medical Education International. There is a dearth of published studies of CLE quality in Singapore. Objective Our study had 3 aims: (1) to measure the CLE in 1 Singaporean residency program; (2) to compare trainee perceptions by sex, training level, and experience; and (3) to identify areas for improvement. Methods Between October and December 2017, we conducted a mixed assessment of the CLE in an internal medicine program in Singapore, using the Postgraduate Hospital Educational Environment Measure (PHEEM) and qualitative exploration using a focus group. Results Of 153 IM residents, 136 (89%) provided PHEEM responses and 8 participated in the focus group. Total PHEEM scores and scores for the 3 subscales were higher than published data on the use of the PHEEM in international settings. Exploration of selected PHEEM responses via a focus group identified attributes associated with negative perceptions of the CLE: excessive workload, inadequate faculty presence in the CLE, and unmet trainee needs. It also suggested senior residents' clinical workloads, greater responsibilities, and pending examinations may contribute to their less positive perceptions of the CLE. Conclusions Our analysis using the PHEEM showed overall positive perceptions of the CLE, along with areas for improvement amenable to interventions. Our approach has relevance to an accreditation model with ongoing evaluation of the CLE.

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Danilov, Daniil, Nikolai Drobotun, Aleksei Medvedev et Vladimir Ulyanov. « Electronic calibrator MMIC with frequency range up to 50 GHz for vector network analyzers in GaAs pHEMT technology ». ITM Web of Conferences 30 (2019) : 01002. http://dx.doi.org/10.1051/itmconf/20193001002.

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This paper presents design, simulation and measurements results of electronic calibrator with frequency range up to 50 GHz in GaAs pHEMT technology. MMIC was fabricated by using in-house 0,5 um pHEMT process. Designed MMIC performs SOLT calibration method with additional measures

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