1,720,960 research outputs found
Novel biodegradable hydrogel scaffold based on hydroxyapatite eggshell, collagen, and epigallocatechin‑3‑gallate
Get PDFBackground: Biodegradable hydrogel scaffold is one of the crucial characteristics that
determine the success of pulp regeneration. The degradation should be suitable for the
growth of new tissue establishment. The aim of this study is to synthesize and compare the
novel biodegradable hydrogel scaffold based on hydroxyapatite (HAp) eggshell, collagen, and
epigallocatechin‑3‑gallate (HAp‑Col‑EGCG) with different HAp concentrations in vitro.
Materials and Methods:This study is original research. HAp‑Col‑EGCG hydrogel scaffolds were
prepared using 1:1, 1:2, and 1:4 ratios of collagen and HAp with 10 µmol/L EGCG. The samples
were freeze‑dried and immersed in phosphate buffer saline containing lysozyme enzyme. The dried
samples were weighed to determine the percentage of biodegradation value (P < 0.05).
Results: The result showed HAp‑Col‑EGCG was biodegradable but it has not been concluded
that it can be completely eliminated. The data were analyzed by one‑way analysis of variance and
it indicated significant differences in percentage values.
Conclusion: Hydrogel scaffold based on HAp‑Col‑EGCG can be degraded and have the potential
to be used as a biodegradable scaffold in supporting tissue regeneration
The Toxicity Assessment of The Nanohydroxyapatite, Epigalocathecine-3-Gallate, And Hydroxyprophil Methylcellulose Hydrogel
Get PDFThe previous study showed that the hydroxyapatite, Epigalocathecine-3-Gallate (EGCG), and hydroxypropyl methylcellulose (HAp-EGCG-HPMC) material has the potential to be combined into a useful material in the field of dentistry, and one of them is as a pulp regeneration material. To determine the safety of the HAp-EGCG-HPMC formulation, the characterization of this new material should be performed using the cytotoxicity and proliferation test. It can show the number of living cells and it can indicate the vitality mechanism in certain proteins, also knowing the cell survival after exposure to HAp-EGCG-HPMC material. The method used to detect cell proliferation is commonly similar to the viability test. The cytotoxicity and proliferation were performed Methods: The HAp-EGCG-HPMC hydrogel was made by dissolving hydroxyapatite powder in distilled water to make a concentration of 1%, 2%, 4% with 10μmol/mL EGCG, and hydroxypropyl methylcellulose carriers were added. The cytotoxicity and proliferation in fibroblast cells of HA-EGCG-HPMC hydrogel was done using by CCK-8 dye and read by spectrophotometer with 450nm wavelength. Results: Hydroxyapatite, EGCG, and HPMC hydrogels were nontoxic to fibroblast cells 24 hours after mixing and it can induce proliferation of fibroblast cells. Conclusion: The hydrogel containing hydroxyapatite, EGCG, and HPMC is non-toxic and promotes the proliferation of fibroblast cells, making it suitable as a material for pulp regeneration
Diametral Tensile Strength of Microhybrid and Nanohybrid Composite Resins
No full text
Introduction: Microhybrid and nanohybrid composite resins are commonly used due to their high diametral tensile strength, which indicates the resistance of a material to chewing in posterior tooth restoration. Both composite resins have been widely produced via various modifications of their composition.
Objectives: To evaluate the diametral tensile strength of composite resins with microhybrid and nanohybrid fillers.
Methods: In this experimental laboratory study, microhybrid (DenFilTM) and nanohybrid (DenFilTM N) composite resins were shaped into 10 specimens each in cylindrical molds (6 mm diameter × 3 mm height) by the bulk-fill technique, and the upper layer was flattened using mylar strips and then polymerized using a light-curing unit for 20 s. Then, composite resin samples were immersed in cell culture plates filled with 2.5 mL of artificial saliva in a 37°C incubator for 24 h. Dimensions of the soaked specimens were examined using a digital caliper and tested using a universal testing machine.
Results: The diametral tensile strength values for microhybrid and nanohybrid composite resins were 41.67 MPa and 45.42 MPa, respectively.
Conclusion: There was no significant difference in the diametral tensile strength of microhybrid and nanohybrid
Synthesis and Physical Characterization of Nano-Hydroxyapatite-Collagen-Epigallocatechin-3-Gallate Hydrogel Composite
Get PDF
Introduction: Most commonly used vital pulp therapy material is calcium hydroxide (Ca(OH)2) but it has several disadvantages. Previous studies found that nano-hydroxyapatite might induce reparative dentin with no tunnel defect and adding collagen can improve hydroxyapatite mechanical properties. The collagen can also increase pulp cell proliferation and differentiation. The addition of Epigallocatechin-3-Gallate (EGCG) to collagen gel can be beneficial in reducing pulp inflammation.
Objective: The purpose of this study is to synthesize and analyze the physical characteristics of the nano-Hydroxyapatite-collagen-Epigallocatechin-3-Gallate hydrogel composite.
Methods: Nano-hydroxyapatite from chicken egg shells, 0,2 g/mL collagen type I, and 10 mmol/L EGCG each dissolved in 2 mL deionized water with various ratio of nano-hydroxyapatite:collagen, 40:60 (group 1), 50:50 (group 2), and 60:40 (group 3). Each solution was mixed together then 2% HPMC was added into the mixture. In present study, we observed hydrogel composite pH value, gelation time, and injectability analysis.
Results: The pH value in 1 hour stirring for each group was 8,05 ± 0,05, 8,43 ± 0,02, and 8,71 ± 0,04. All samples had 1 hour gelation time. Injectability for each group was 90,67%, 91,93%, and 95,03%.
Conclusions: The nanohydroxyapatite, collagen and EGCG hydrogel composite has a potential physical characterization to be used as a vital pulp therapy material based on its pH value and injectable ability but further study should be considered in determining ideal gelation time.
ABSTRAK
Pendahuluan: Bahan perawatan pulpa vital yang paling umum digunakan adalah kalsium hidroksida (Ca(OH)2), tetapi bahan tersebut memiliki beberapa kekurangan. Penelitian sebelumnya menunjukkan nano-hidroksiapatit mampu merangsang pembentukan dentin reparatif tanpa tunnel defect dan penambahan kolagen mampu meningkatkan sifat mekanik hidroksiapatit. Penambahan Epigallocatechin-3-Gallate (ECGC) pada gel kolagen bermanfaat dalam mengurangi respon inflamasi pulpa.
Tujuan: Penelitian ini dilakukan untuk mensintesis dan melakukan uji karakteristik fisik komposit hidrogel nano-hidroksiapatit-kolagen-Epigallocatechin-3-Gallate.
Metode: Nano-hidroksiapatit dari cangkang telur ayam dilarutkan dengan 0,2 g/mL kolagen tipe I, dan 10 mmol/L EGCG masing-masing ke dalam air deionisasi dengan perbandingan rasio nano-hidroksiapatit dan kolagen, 40:60 (kelompok 1), 50:50 (kelompok 2), dan 60:40 (kelompok 3). Seluruh larutan dicampurkan dan ditambahkan HPMC 2%, lalu dilakukan uji karakteristik gel berupa uji pH, waktu gelasi, dan uji injektabilitas.
Hasil: Nilai pH 1 jam setelah pengadukan secara berurutan adalah 8,05 ± 0,05, 8,43 ± 0,02, dan 8,71 ± 0,04 dengan waktu gelasi selama 1 jam. Injektabilitas secara berurutan adalah 90,67%, 91,93%, dan 95,03%.
Kesimpulan: Bahan komposit hidrogel nano-hidroksiapatit, kolagen, dan EGCG memiliki karakteristik fisik yang berpotensi untuk digunakan sebagai bahan terapi pulpa vital jika dilihat dari nilai pH dan kemampuan injektabilitas yang diperoleh
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Novel biodegradable hydrogel scaffold based on hydroxyapatite eggshell, collagen, and epigallocatechin-3-gallate
No full textBackground: Biodegradable hydrogel scaffold is one of the crucial characteristics that determine the success of pulp regeneration. The degradation should be suitable for the growth of new tissue establishment. The aim of this study is to synthesize and compare the novel biodegradable hydrogel scaffold based on hydroxyapatite (HAp) eggshell, collagen, and epigallocatechin-3-gallate (HAp-Col-EGCG) with different HAp concentrations in vitro.
Materials and Methods: This study is original research. HAp-Col-EGCG hydrogel scaffolds were prepared using 1:1, 1:2, and 1:4 ratios of collagen and HAp with 10 μmol/L EGCG. The samples were freeze-dried and immersed in phosphate buffer saline containing lysozyme enzyme. The dried samples were weighed to determine the percentage of biodegradation value (P < 0.05).
Results: The result showed HAp-Col-EGCG was biodegradable but it has not been concluded that it can be completely eliminated. The data were analyzed by one-way analysis of variance and it indicated significant differences in percentage values.
Conclusion: Hydrogel scaffold based on HAp-Col-EGCG can be degraded and have the potential to be used as a biodegradable scaffold in supporting tissue regeneration
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
