scholarly journals Cell Viability Assessment Using Fluorescence Vital Dyes and Confocal Microscopy in Evaluating Freezing and Thawing Protocols Used in Cryopreservation of Allogeneic Venous Grafts

2021 ◽  
Vol 22 (19) ◽  
pp. 10653
Author(s):  
Pavel Měřička ◽  
Libor Janoušek ◽  
Aleš Benda ◽  
Radka Lainková ◽  
Ján Sabó ◽  
...  
Keyword(s):  
Freezing And Thawing ◽  
Tissue Slices ◽  
Viability Assessment ◽  
Vital Dyes ◽  
Venous Grafts ◽  
Nitrogen Vapor ◽  
The Subject ◽  
The Mean ◽  
Revascularization Procedures

The authors present their contribution to the improvement of methods suitable for the detection of the freezing and thawing damage of cells of cryopreserved venous grafts used for lower limb revascularization procedures. They studied the post-thaw viability of cells of the wall of cryopreserved venous grafts (CVG) immediately after thawing and after 24 and 48 h culture at +37 °C in two groups of six CVG selected randomly for slow thawing in the refrigerator and rapid thawing in a water bath at +37 °C. The grafts were collected from multi-organ and tissue brain-dead donors, cryopreserved, and stored in a liquid nitrogen vapor phase for five years. The viability was assessed from tissue slices obtained by perpendicular and longitudinal cuts of the thawed graft samples using in situ staining with fluorescence vital dyes. The mean and median immediate post-thaw viability values above 70% were found in using both thawing protocols and both types of cutting. The statistically significant decline in viability after the 48-h culture was observed only when using the slow thawing protocol and perpendicular cutting. The possible explanation might be the “solution effect damage” during slow thawing, which caused a gentle reduction in the graft cellularity. The possible influence of this phenomenon on the immunogenicity of CVG should be the subject of further investigations.

Direct Observations of the Epitaxial Growth of Sputtered Ag on Si

1973 ◽  
Vol 31 ◽  
pp. 122-123
Author(s):  
J. S. Maa ◽  
Thos. E. Hutchinson
Keyword(s):  
Epitaxial Growth ◽  
Film Growth ◽  
Ion Beam ◽  
Ion Beam Sputtering ◽  
Microscopy Technique ◽  
Direct Observations ◽  
In Situ Electron Microscopy ◽  
Beam Sputtering ◽  
The Subject

The growth of Ag films deposited on various substrate materials such as MoS2, mica, graphite, and MgO has been investigated extensively using the in situ electron microscopy technique. The three stages of film growth, namely, the nucleation, growth of islands followed by liquid-like coalescence have been observed in both the vacuum vapor deposited and ion beam sputtered thin films. The mechanisms of nucleation and growth of silver films formed by ion beam sputtering on the (111) plane of silicon comprise the subject of this paper. A novel mode of epitaxial growth is observed to that seen previously.The experimental arrangement for the present study is the same as previous experiments, and the preparation procedure for obtaining thin silicon substrate is presented in a separate paper.

Applying Circle Game to Enhance Students’ Speaking Skill

2020 ◽  
Vol 7 (2) ◽  
pp. 119
Author(s):  
Putri Denaya Side Ayu ◽  
Heri Hidayatullah ◽  
Sri Ariani
Keyword(s):  
Action Research ◽  
Learning Process ◽  
Active Involvement ◽  
Post Test ◽  
Speaking Skill ◽  
The Subject ◽  
The Mean ◽  
Classroom Action Research ◽  
Speaking Skills

This Collaborative Classroom Action Research aimed at enhancing students’ speaking skill through the application of Circle Game. It was conducted in one cycle consisting of two meetings. The subject was the seventh of C class of SMPN 2 Alas Barat consisting of 22 students. The types of data were qualitative (acquiring observation during the learning process) and quantitative (speaking tests). The results qualitatively showed that the implementation of Circle Game enhanced the students’ speaking skills. Such improvement could be seen from their enthusiasm, their interesting feeling in various materials presented by the teacher, their active involvement. In the quantitative findings, the result also showed a higher value of the mean score of the post-test (77.34) rather than the pre-test (75.75). In conclusion, the use of Circle Game can improve students’ speaking skill.

UPAYA MENINGKATKAN HASIL BELAJAR IPA MELALUI PENGGUNAAN VIDEO PEMBELAJARAN BAGI SISWA KELAS IV DI SDN 187/IV KOTA JAMBI

2015 ◽  
Vol 8 (2) ◽  
pp. 93
Author(s):  
Juniar Siregar
Keyword(s):  
Action Research ◽  
Research Method ◽  
Research Report ◽  
The Third ◽  
The Media ◽  
The Subject ◽  
The Mean ◽  
Classroom Action Research

This study presents a research report on improving students’ Learning results on IPA through Video. The objective was to find out whether students’ learning result improved when they are taught by using Video. It was conducted using classroom action research method. The subject of the study was the Grade IV students of SDN 187/IV Kota Jambi which is located on Jln. Adi Sucipto RT 05 Kecamatan Jambi Selatan, and the number of the students were 21 persons. The instruments used were test. In analyzing the data, the mean of the students’ score for the on fisrt sycle was 65,4 (42,85%) and the mean on cycle two was 68,5 (37,15%) and the mean of the third cycle was 81,4 (100%). Then it can be concluded that the use of video on learning IPA can improve the students’ learning result. It is suggested that teachers should use video as one of the media to improve students’ learning result on IPA.Keywords : IPA, students’ learning result, video

THE USE OF COMMUNITY LANGUAGE LEARNINGMETHOD TO IMPROVE STUDENTS’ SPEAKING ACHIEVEMENT

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Eko Widoyo Putro ◽  
Berlin Sibarani
Keyword(s):  
Language Learning ◽  
Secondary Data ◽  
Primary Data ◽  
Second Grade ◽  
Learning Method ◽  
Field Notes ◽  
The Subject ◽  
The Mean ◽  
Method Improvement ◽  
Community Language

This study is aimed at improving the second grade of students’ speakingachievement by using Community Language Learning (CLL) Method. Theresearch was conducted by applying classroom action research. The subject of this study was second grade of Private Senior High School (Sekolah Menengah Atas Swasta) of Dwi Tunggal Tanjung Morawa which consisted of 31 students. To collect the data, the instruments used were primary data (SpeakingTest) and secondary data (interview sheet, observation sheet, field notes). It can be seen from the score in test I, test II and test III. In the Test I, the mean of the students’score was (64.77), in the Test II was (71.35), and the mean of the students’ score of the Test III was (80.90). Based on the interview, and observation sheet, it shows that the expression and excitement of the students got improved as well. It was found that teaching of speaking by using Community Language Learningcould significantly improve students’ speaking achievement.Key Words: Community Language Learning, Method, Improvement, Speaking Achievement

IMPROVING STUDENTS’ ACHIEVEMENT IN READING NARRATIVE TEXT BY USING RECIPROCAL TEACHING METHOD

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
Ruth Adelina Sianturi ◽  
Sumarsih Sumarsih
Keyword(s):  
Reading Comprehension ◽  
Teaching Method ◽  
Narrative Text ◽  
Reciprocal Teaching ◽  
Teaching Reading ◽  
Multiple Choice Tests ◽  
Choice Tests ◽  
Tenth Grade ◽  
The Subject ◽  
The Mean

This study deals with the improving students’ achievement in reading narrative text by using reciprocal teaching. The research of this study was conducted by using action research. The subject of this study was the tenth grade students SMA Negeri 6 Medan. One class was taken as the subject, namely the students from X-5. There were 49 students, consisting of 22 male and 27 female. This research was done in two cycles; there was three meetings in cycle I and three meetings in cycle II. The instruments for collecting data were reading narrative text (25 items of multiple choice tests) teacher make test as quantitative data and interview sheet, observation sheet and diary notes as qualitative data. In analyzing the data, the mean of the students’ score for the treatment I was 61.79, for the treatment II was 72.24 and treatment III was 81.71. The data showed that the students’ score was rising in every treatment. The conclusion is that the use of reciprocal teaching method can improve students’ reading comprehension in narrative text. It suggested to English teacher to apply reciprocal teaching method in teaching reading comprehension. Key words: reading, narrative text, reciprocal teaching.

IMPROVING STUDENTS’ ACHIEVEMENT IN WRITING RECOUNT TEXT THROUGH THINK PAIR SHARE

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
Hotria Manik ◽  
Elia Masa Ginting
Keyword(s):  
Action Research ◽  
Quantitative Data ◽  
Qualitative Data ◽  
Writing Achievement ◽  
The Third ◽  
Post Test ◽  
Class Viii ◽  
The Subject ◽  
The Mean ◽  
Writing Tests

This study attempts to improve students’ writing achievement in recount text through Think-Pair-Share Strategy. This study was conducted by using classroom action research. The subject of the research was class VIII-1 SMPN 1 Pematangsiantar. The number of the students was 32 students, consisted of 5 males and twenty seven females. The research was conducted in two cycles and consisted of six meetings. The instruments for collecting data were writing tests as the quantitative data and diary notes, observation sheet, interview sheet and questionnaire sheet as qualitative data. Based on the writing score, students’ scores kept improving in every test. In analyzing the data, the mean of the students’ score for the first test as a pre-test was 57.84, for the second test as a post test I was 73.56, for the third test as a post test II was 77.56. Based on diary notes, observation sheet and questionnaire sheet, it was found that students were actively involved in writing process. The result of the research showed that Think-Pair-Share Strategy can improve students’ achievement in writing recount text.   Keywords: Think Pair Share, Writing, Recount text, Action research

IMPROVING THE STUDENTS’ READING COMPREHENSION ACHIEVEMENT IN DESCRIPTIVE TEXT THROUGH TEAM GAMES TOURNAMENT

2014 ◽  
Vol 3 (3) ◽  
Author(s):  
DesiYusnanda Sari And Sri MindaMurni
Keyword(s):  
Reading Comprehension ◽  
Learning Process ◽  
Quantitative Data ◽  
Qualitative Data ◽  
Reading Scores ◽  
Team Games ◽  
The Subject ◽  
The Mean ◽  
Teaching Learning ◽  
Data Reading

This study attempted to improve the students’ reading comprehension achievement in descriptive text through Team Games Tournament (TGT) method. This study was conducted by using classroom action research. The subject of the research was class IX SMP PAB 10 Medan Estate which consisted of 25 students. The research was conducted in two cycles and the first cycle consisted of four meetings the second cycle consisted of two meetings. The instruments for collecting the data were quantitative data (reading evaluation) and qualitative data (diary note, observation sheet and interview sheet). Based on reading scores, students’ score kept improving in every evaluation. In the test I the mean was 65,33, in the test II the mean was 71,72 and the test III the mean was 84,54.Based on diary note, observation sheet and interview sheet, it was found that teaching-learning process ran well. Students were active, enthusiastic, and interested in reading. The result of the research showed that Team Games Tournament (TGT) method significantly improved students’ achievement in reading comprehension especially in reading descriptive text.

IMPROVING STUDENTS’ WRITING ACHIEVEMENT THROUGH THE PROCESS GENRE APPROACH

2013 ◽  
Vol 2 (2) ◽  
Author(s):  
Sri Wuri Handayani And Masitowarni Siregar
Keyword(s):  
Action Research ◽  
Learning Process ◽  
Qualitative Data ◽  
Score Test ◽  
Writing Achievement ◽  
The Subject ◽  
The Mean ◽  
Teaching Learning ◽  
Orientation Test ◽  
Interview Questionnaire

This study attempts to Improving Students’ Achievement Through the Process GenreApproach. The objective of the study is to discover whether the use of the ProcessGenre approach could significantly improve students’ writing achievement. This studyconduct by applying Classroom Action Research which was carried out in two cycles inten meetings. The subject of this study of SMA Panca Budi Medan which consisted of39 students of class X – 2 reguler.. Orientation test was done in the first meeting, test IIwas done in the fourth meeting, and test III was done in the last meeting. The mean ofstudents’ score test III (76,242) was higher than the test II (66,878) and test I (57,606).Besides, the qualitative data was taken from observation sheet, interview, questionnaire,and diary notes. It was found that teaching learning process ran well. By applying theProcess Genre Approach in the classroom, the students understood the content ofdescriptive text easily. They also were active and enthusiastic during the teachinglearning process. The result of the research showed that the application of the ProcessGenre approach significantly improved students’ achievement in writing descriptive text

IMPROVING STUDENTS’ ACHIEVEMENT IN SPEAKING THROUGH TWO STAY TWO STRAY STRATEGY

2013 ◽  
Vol 2 (2) ◽  
Author(s):  
Dita Masyitah Sianipar And Sumarsih
Keyword(s):  
Action Research ◽  
Learning Process ◽  
Quantitative Data ◽  
Test Score ◽  
Qualitative Data ◽  
Speaking Test ◽  
The Subject ◽  
The Mean ◽  
Teaching Learning ◽  
The Way

This study deals with the way to improve students’ achievement in speaking particularly through Two Stay Two Stray Strategy. This study was conducted by using classroom action research. The subject of of the research was class X-AP SMK Swasta Harapan Danau Sijabut in Asahan Regency that consisted of 34 students. The research was conducted in two cycles consisted of three meetings in each cycle. The instruments of collecting data for quantitative data used Speaking Test and instrument for analysis of qualitative data used observation, interview and questionnaire sheet. Based on the speaking test score, students’ score kept improving in every test. In the test I the mean was 61,47, in the test II the mean was 67,41 and the test III the mean was 78,52. Based on observation sheet and questionnaire sheet, it was found that teaching learning process run well and lively. Students were active and interest in speaking. The using of Two Stay Two Stray Strategy is significantly improved students’ achievement in speaking.

IMPROVING GRADE V STUDENTS’ VOCABULARY ACHIEVEMENT THROUGH FLASH CARDS

2014 ◽  
Vol 3 (1) ◽  
Author(s):  
Sabatini Sitorus And Masitowarni Siregar
Keyword(s):  
Action Research ◽  
Learning Process ◽  
Qualitative Data ◽  
Vocabulary Test ◽  
Flash Cards ◽  
The Subject ◽  
The Mean ◽  
Classroom Action Research ◽  
Teaching Learning ◽  
Vocabulary Achievement

This study attempts to increase students’ vocabulary achievement by using flash cards. The objective of the study is to investigate whether the using of flash card can improve students’ vocabulary achievement. This study conduct by applying Classroom Action Research which was carried out in two cycles in six meetings. The subject of this study of SD Negeri 174559 Siraituruk, Porsea which consisted of 34 students. For collecting data, the instruments used were quantitative (vocabulary test) and qualitative data (interview sheet, observation sheet, and diary notes. Based on the data, it was found that the mean of the second cycle (80, 44) is higher than the mean of first cycle (64, 85) and pre-test (44, 41).  Based on interview sheet, observation sheet and diary notes, it was found thee students were more active and more enthusiastic during the teaching learning process in the second cycle than the first one. It was concluded that teaching vocabulary by using  flash cards can improve the students’ vocabulary achievement.

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