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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
Application of Hexagonal Boron Nitride to a Heat-Transfer Medium of an InGaN/GaN Quantum-Well Green LED
No full textGroup III-nitride light-emitting diodes (LEDs) fabricated on sapphire substrates typically suffer from insufficient heat dissipation, largely due to the low thermal conductivities (TCs) of their epitaxial layers and substrates. In the current work, we significantly improved the heat-dissipation characteristics of an InGaN/GaN quantum-well (QW) green LED by using hexagonal boron nitride (hBN) as a heat-transfer medium. Multiple-layer hBN with an average thickness of 11 nm was attached to the back of an InGaN/GaN-QW LED (hBN-LED). As a reference, an LED without the hBN (Ref-LED) was also prepared. After injecting current, heat-transfer characteristics inside each LED were analyzed by measuring temperature distribution throughout the LED as a function of time. For both LED chips, the maximum temperature was measured on the edge n-type electrode brightly shining fabricated on an n-type GaN cladding layer and the minimum temperature was measured at the relatively dark-contrast top surface between the p-type electrodes. The hBN-LED took 6 s to reach its maximum temperature (136.1 degrees C), whereas the Ref LED took considerably longer, specifically 11 s. After being switched off, the hBN-LED took 35 s to cool down to 37.5 degrees C and the Ref-LED took much longer, specifically 265 s. These results confirmed the considerable contribution of the attached hBN to the transfer and dissipation of heat in the LED. The spatial heat-transfer and distribution characteristics along the vertical direction of each LED were theoretically analyzed by carrying out simulations based on the TCs, thicknesses, and thermal resistances of the materials used in the chips. The results of these simulations agreed well with the experimental results.
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
Bioactive glass 와 ursolic acid 를 함유한 복합 레진의 6개월 증류수 저장 후 Streptococcus mutans 바이오 필름에 대한
No full textDept. of Dentistry/석사1. Objective
The aim of this study was to investigate the S.mutans biofilm formation on composite
surface containing bioactive glass and ursolic acid when exposed to distilled water for 6
months compared with fresh antibacterial composite resin specimen.
2. Materials and methods
Four experimental groups and one control group were prepared : Conventional
composite (10%wt OX50 silica nanofiller instead of BAG) as control, BAG filler group
(BAG), BAG filler coated with UA group (UA BAG), UA added to resin matrix (BAG+UA
Monomer), and UA added to BAG and resin matrix (UA BAG+UA Monomer). All
specimens were stored in distilled water for 6 months (the aged resin group). After
sterilization with ethylene oxide gas, biofilm assay was performed again on all five groups.
The specimens for the aged resin group were fabricated on the previous study by Kim
(Kim B, 2013), and re-used for this study.
For biofilm assay, S. mutans was incubated for 24 hours with each composite resin disk
specimen in a biofilm medium with either glucose or sucrose in the presence or absence of
a salivary coating. The adherent bacteria were quantified after sonication of the specimen
by counting the colony forming units of viable bacteria.
Calcium and fluoride ions concentration released from new and aged specimens were
analyzed quantitatively by using Ion Chromatography (IC).
Five disk specimens of each group were immersed and stored in 5 ml distilled water for
24 hours. The measurement of ion release was carried out by using the IC on 1-day
interval for 7 days.The t-test for variable CFU was used for biofilm assay to analyze statistical significance between new and aged groups. To analyze the effect of composite composition on the biofilm formation, one-way analysis of variance (ANOVA) followed by a multiplecomparison Tukey test was performed. The amount of calcium and fluoride ion release between old resin groups and new resin groups was compared using t- test at a 5% level of significance.
3. Result
When glucose was given as a carbohydrate source, there was no significant difference
between new and aged resin under saliva non-coating condition. In new resins, the CFU
values of all experimental groups were significantly lower than control group. However, in
aged resin, only the BAG + UA Monomer group showed significantly lower CFU value than
control group. In saliva coating condition, the CFU value of all aged resin groups
significantly increased compared to all new resin groups. In the new resin groups, the CFU
value of all experimental groups was significantly lower than control. However, there was
no significant difference between control and BAG group on aged resin.
When sucrose was given as a carbohydrate source, under salivary non-coating condition,
CFU value of aged resin significantly increased more than new resin on all experimental
groups except in the control group. In the new resin groups, the CFU value of BAG + UA
Monomer, UA BAG + UA Monomer group was significantly lower than control. However,
there was no significant difference between all groups in aged resin groups. In saliva
coating condition, the CFU value of BAG + UA monomer, UA BAG + UA Monomer group
was significantly lower than control group in aged resin and new resin.
On both calcium and fluoride, new resin showed higher amount of ion release than aged
resin. A significant difference was shown on fluoride ion release all day, and new resin
showed significantly higher release of calcium ion on the 1st, 5th day. On both calcium and
fluoride, a significantly high concentration of ion release was shown on the 1st day in new
resin specimen. The amount of ion release showed significant decrease on the 2nd day, but
increased on the 3rd day.
4. Conclusion
In glucose source, experimental new composites containing BAG and/or UA showed
significant reduction of biofilm formation by S. mutans. However, after storage in distilled
water for 6 months, experimental composites containing BAG showed decreased biofilm
inhibition effect. The composites with UA added to the monomer still showed significant
inhibition effect of the biofilm formation by S. mutans even after storage in distilled water.
In sucrose source, the new composites of UA Monomer group showed significant
antibacterial effect under any salivary treatment. After storage in distilled water for 6
months, the biofilm formation was affected by salivary treatment. In Saliva non-coating
groups, there were no significant difference in all groups, and in saliva coating groups, BAG
+ UA Monomer and UA BAG + UA Monomer groups showed lower CFU values.
Following the results of this experiment, it can be concluded that the UA incorporated in
monomer was more effective method to keep the antibacterial effect in any biofilm
formation condition after 6 month water storage condition.
Within the limitation of this experiment, this result indicates that UA inhibits biofilm
formation by S. mutans and suggests that UA has potential for use as an effective
antibacterial agent to prevent dental caries in the future.ope
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
The Study on the Recovery of Epidermal Langerhans Cells in C3H Mice After UVA Irradiation
No full text의학과/석사[영문]
[한글]
자외선 조사로 인해 표피 Langerhans세포의 형태와 수에 변화가 생긴다는 사실은 널리
보고되었으며 이러한 Langerhans세포의 변화는 조사된 자외선량에 비례한다는 것도 알려
져 왔다. 자외선 조사후 감소된 표피 Langerhans세포수의 시간경과에 따른 회복 양상에
대하여는 자외선 B 및 PUVA의 경우 많은 연구보고들이 있으나 자외선 A에 대해서는 자세
한 보고가 별로 없다. 더우기 동량의 자외선을 분할하여 수일간 조사한 경우와 1회 단시
간에 집중조사한 경우의 시간경과에 따른 회복양상의 비교는 아직 상세히 연구되어진 바
없는 것으로 생각된다
이에 저자들은 C^^3 H생쥐에서 조사량과 조사방법을 달리하여 자외선A를 조사한후 시간
경과에 따른 표피 Langerhans세포의 회복을 보고자 C^^3 H생쥐의 귀부위에 200J/㎠ 및 40
0J/㎠의 자외선 A를 각각 1회 집중조사 및 5일에 걸쳐 5회 분할조사한 후 자외선을 조사
받지 않은 정상대조군과 실험군의 귀부위를 생검하고 면역과산화효소 염색(immuno-peroxi
dase stain)을 시행하여 Ia양성 표피 Langerhans세포수를 관찰한 결과 다음과 같은 결과
를 얻었다.
1. 200J/㎠의 조사군에서는 집중조사군에서 분할조사군에 비해 조사후 7일, 14일에 Ia
양성 표피 Langerhans세포수가 의의있게 감소함을 보였다.
2.400J/㎠의 조사군에서는 분할조사군과 집중조사군사이에 조사 21일후까지 Ia양성 표
피 Langerhans세포수의 변화에 의의있는 차이가 없었다.
3. 자외선A조사후 감소된 Ia양성 표피 Langerhans세포수는 200J/㎠조사군의 분할조사군
에서 조사후 14일에 집중조사군에서 조사후 21일에 정상으로 회복되었으며, 400J/㎠조사
군의 분할조사군과 집중조사군 모두에서 조사후 21일에 정상으로 회복되었다.
이상의 결과로 보아 C^^3 H생쥐에서 Ia양성 표피 Langerhans세포수는 200J/㎠의 자외선
A를 조사한 경우 분할조사군보다 집중조사군에서 조사후 7일, 14일째 더 많이 감소하고
회복도 느리며,200J/㎠ 및 400J/㎠ 조사군 모두에서 조사 21일 후에는 세포수가 정상으로
회복됨을 알 수 있었다. 따라서 일정량의 자외선 A를 조사하는 경우 분할조사가 집중조
사보다 면역학적인 손상이 더 적을 것으로 생각된다.
The Study on the Recovery of Epidermal Langerhans Cells in C^^3 H Mice After UVA
Irradiation
Soo-Min Kim
Department of Medical Science, The Graduate School, Yonsei University
(Directed by Professor Yoon-Kee Park, M.D., Ph.D.)
It has been reported widely that the changes in morphology and number of
epidermal Langerhans cells are brought about by ultraviolet irradiation and it is
known that the changes in Langerhans cells are proportional to the amount of
ultraviolet irradiation. There have been many studies on the aspect of the recovery
of the reduced number of epidermal Langerhans cells in relation to time after
ultraviolet B(UVB)and PUVA irradiation, but not many detailed reports about
ultraviolet A(UVA) have been made, Besides, no study has been done on the aspect of
the recovery in relation to time when an equal amount of ultraviolet rays is
exposed in fractionated doses for a few days compared to when it is exposed in one
single large dose at one time.
To see the recovery in epidermal Langerhans cells in relation to time after UVA
irradiation through different amounts and ways of exposure in C^^3 H mice, we
irradiated the ears of C^^3 H mice with UVA 200J/㎠ and 400J/㎠ in a single dose at
one time and 5 fractionated doses for 5 days and performed biopsies on the ears of
the control and experimental groups after 2, 7, 14, 21 days of irradiation and
stained them with immunoperoxidase method. We obtained the following results after
observing the number of the la-positive epidermal Langerhans cells,
The results are summarized as follows,
1. We observed a significant decrease in the number of the la-positive epidermal
Langerhans cells in the single-dose-exposed group compared to the
fractionated-dose-exposed group on 7th and 14th days irradiated with UVA 200J/㎠.
2. There was no significant difference in the change in the number of the
la-positive epidermal Langerhans cells until 21 days of exposure between the
single-dose-exposed group and the fractionated-dose-exposed group irradiated with
UVA 400J/㎠.
3. In the group irradiated with UVA 200J/㎠, the reduced number of the
la-positive epidermal Langerhans cells returned to normal on the 14th day after
irradiation in the fractionated-dose-exposed group and on the 21st day in the
single-dose-exposed group. In the group irradiated with 400J/㎠, the number
returned to normal on the 21st day of irradition both in the
fractionated-dose-exposed group and in the single-dose-exposed group.
From the results obtained, the number of the la-positive epidermal Langerhans
cells in C^^3 H mice is decreased more and also the recovery is slower in the
single-dose-exposed group than in the fractionated-dose-exposed group on the 7th
and 14th days after irradiation with UVA 200J/㎠ and the number of the cells
returned to normal after 21days of exposure in both groups irradiated with UVA
200J/㎠ and 400J/㎠. Therefore, for an equal amount of UVA irradiation it is
thought that the fractionated-dose-exposed group received less immunological damage
than the single-dose -exposed group.restrictio
(The) effect of various psoralens and ultraviolet A on melanocytes, Langerhans cells and the formation of sunburn cells in C57BL mice
No full text의학과/박사[한글]
광화학요법은 피부의 색소 침착 효과로 인해 백반증 치료에 쓰이고 있다. 광화학요법에
사용되는 약물인 psoralen은 직선구조 및 각구조로 구분된다. 직선구조를 갖는 8-methox
ypsoraven(8-MOP) 및 5-methoxypsoralen(5-MOP)은 이중 작용기 (bifunctional) psoralen
으로 자외선 A를 조사하였을 때 세포 DNA 가닥 사이에 교차결합을 일으키며 돌연변이, 발
암성, 광독성 반응 등의 부작용을 초래할 수 있다. 반면 각구조를 갖는 angelicin은 단일
작용기(monofunctional) psoralen으로 자외선 A 조사시 세포 DNA 가닥 사이의 교차결합
을 거의 형성하지 않고 부작용을 비교적 적게 일으킨다. 색소 침착을 위한 광화학요법에
서는 멜라닌세포수와 크기를 증가시키면서 광독성 반응 및 면역학적 변화를 적게 일으키
는 약제의 선택이 바람직하다.
본 연구에서는 직선구조를 갖는 8-MOP과, 역시 직선구조이나 8-MOP에 비해 부작용이 적
다고 알려진 5-MOP, 그리고 각구조를 갖는 angelicin을 이용한 광화학요법을 시행하여 5-
MOP및 angelicin이 현재 백반증 치료에 사용되고 있는 8-MOP에 비해 멜라닌세포의 수와
크기에 미치는 영향이 어떠한가를 알아보고, 또한 광화학요법 후 초래되는 면역학적 이상
에 중요한 역할을 하리라 생각되는 랑게르한스세포 감소와, 광독성 반응의 지표가 되는
일광화상세포 형성에 미치는 각 약물의 영향을 비교하고자 하였다. 즉 C57BL 마우스에 8-
MOP, 5-MOP 및 angelicin을 이용한 전신 광화학요법을 시행하고 광화학요법 1주, 3주 및
6주에 피부를 생검한 후 dihydroxyphenylalanine(DOPA) 양성 멜라닌세포의 수, 면적 및
둘레길이와 ATPase 양성랑게르한스센포 수, 그리고 표피의 일광화상세포 수를 측정하여
다음의 결과를 얻었다.
1. 멜라닌세포 수는 8-MOP 투여군, angelicin 투여군, 5-MOP 투여군 모두에서 대조군에
비해 유의하게 증가하였으나 각 약물 투여군간에 유의한 차이가 없었다.
2. 멜라닌세포 면적 및 둘레길이는 8-MOP 투여군, angelicin 투여군, 5-MOP 투여군, 대
조군의 순으로 증가하였으며 광화학요법 6주에 8-MOP 투여군 및 angelicin 투여군에서 5-
MOP투여군에 비해 유의하게 증가하였다.
3. ATPase 양성 표피 랑게르한스세포 수는 8-MOP 투여군, 5-MOP 투여군, angelicin 투
여군, 대조군의 순으로 감소가 많았으며 8-MOP 투여군에서 5-MOP 투여군 및 angelicin 투
여군에 비해 유의하게 감소하였다.
4. 일광화상세포 수는 8-MOP 투여군, 5-MOP 투여군, angelicin 투여군, 대조군의 순으
로 증가하였으며 8-MOP 투여군에서 5-MOP 투여군 및 angelicin 투여군에 비해 유의하게
많이 형성 되었다.
이상의 결과로 보아 멜라닌세포 수, 면적 및 둘레길이 증가가 angelicin 투여군 및 5-M
OP투여군에서 현재 백반증 치료에 사용되고 있는 약물인 8-MOP 투여군에 비해 손색이 없
었으며, ATPase 양성 랑게르한스세포 감소와 일광화상세포 형성은 angelicin 투여군 및 5
-MOP 투여군에서 8-MOP 투여군에 비해 적었으므로 색소 침착을 목적으로 하는 백반증의
치료에 angelicin 및 5-MOP을 이용한 광화확요법이 좋은 방법이 될 가능성이 있다고 생각
된다.
[영문]
The combination of psoralen and subsequent exposure of ultraviolet A(UVA) is used
with increasing importance in the treatment of vitiligo. There are two forms of
psoralens. Linear psoralens and angular psoralens. Linear psoralens, such as
8-methoxypsoralen(8-MOP) and 5-methoxypsoralen (5-MOP),are photochemically
bifunctional psoralens which can form interstrand cress-linking with DNA and may
induce mutagenic and carcinogenic side effects in the presence of UVA. Angular
psoralens, such as angelicin, are photochemically monofunctional psoralens and
rarely form interstrnnd cross-linking with DNA on irradiation and consequently lead
to less side effects than linear psoralens. For the purpose of increment of
pigmentation, photosensitizing agents should be selected which increase the number
and size of melanocytes while minimizing phototoxic reactions and immunologic
alterations in the presence of UVA.5-MOP, a bifunctional psoralen, showed less side
effects such as phototoxic reactions, mutation, and gastrointestinal problems than
8-MOP in the photochemotherapy. Angelicin is a monofunctional psoralen and the
effect of angelicin on the number and size of melanocyte with UVA irradiation is
still unknown.
The objectives of this study are to compare the effects of photochemotherapy of
linear psoralens,8-MOP and 5-MOP, and an angular psoralen, angelicin. In
particular, the number and size of melanocytes formed, the number of Langerhans
cells which are important in immune surveillance system and the number of sunburn
cells which are the quantitative index of phototoxic reactions are compared. For
this purpose, we injected these psoralens intraperitoneally into C57BL mice and
subsequently exposed the mice to 4 J/cm**2 of UVA twice a week for 6weeks. We
biopsied the skin at 1,3 and 6weeks of photochemotherapy, and stained them with
DOPA stain, ATPase stain, and hematoxylineosin stain to measure the number, area
and perimeter of melanocytes formed, the number of ATPase**+ Langerhans cells and
the number of sunburn cells. The results are summarized as follows:
1. There were increases in the number of melanocytes in groups treated with
8-MOP, 5-MOP and angelicin compared with the UVA-only treated group. No
statistically significant difference between groups treated with phototoxic drugs
was observed.
2. There were marked increases in the area and the perimeter of melanocytes in
groups treated with 8-MOP, angelicin and 5-MOP compared with the UVA-only treated
group. Groups treated with 8-MOP and angelicin showed statistically significant
increases in the area and the perimeter of melanocytes than the group treated with
5-MOP in the 6th week of treatment.
3. Threr were marked reductions in the number of ATPase**+ Langerhans cells in
groups treated with all of phototoxic drugs compared to the UVA-only treated group.
in the group treated with 8-MOP, there was statistically significant decrease in
the number of ATPase**+ Langerhans cells than 5-MOP and angelicin treated groups.
4. There were increased formations of sunburn cells in all groups treated with
phototoxic drugs compared to the UVA-only treated group. In the 8-MOP treated
Broup, the number of sunburn cells was larger than that of 5-MOP and angelicin
treated groups.
In summary, 5-MOP and angelicin showed similar pigmentation with less side
effects than 8-MOP, a commonly used psoralen for the treatment of vitiligo, and we
have found encouraging possibilities for 5-MOP and angelicin to be useful
photochemotherapeutic drugs.restrictio
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