Research Express@NCKU

Research Express@NCKU - Articles Digest
Research Express@NCKU
Volume 27 Issue 8 - October 24, 2014
[ http://research.ncku.edu.tw/re/articles/e/20141024/1.html ]
Spatially reinforced Au nano-cavities as a reaction
nano-reservoir for trace analysis of DNA hybridization
Chih-Kai Yaoa, Jiunn-Der Liaoa,* , Chih-Heng Linb, Yuh-Shyong Yangb, Sheng-Hong Yua, JungWei Yanga
a
Department of Materials Science and Engineering, National Cheng Kung University, No. 1,
University Road, Tainan 70101, Taiwan
b Department of Biological Science and Technology, National Chiao Tung University, 75 Po-Ai
Street, Hsinchu 30050, Taiwan
[email protected]
Sensors and Actuators B: Chemical, Volume 191, February 2014, Pages 219–226
S
patially reinforced Au nano-cavities (SR-nAu) with reduced tip-to-tip displacement
create strongly localized surface plasmon resonance by Raman scattering. Within SRnAu, the nano-cavity structure with high aspect ratio was optimized as the nanoreservoir for the distinction of DNA hybridization responses from specific DNA
sequences of Avian influenza virus. In the nano-reservoir, the suspended or
immobilized probe, its complementary and noncomplementary target sequences were
characterized at very low concentration through enhanced Raman spectra. The presence of Raman shift at 738 cm
−1,
the characteristic breathing mode of thymine, and the change of relative peaks intensity at 1603 and 1554 cm−1
before and after hybridization were particularly taken as the major indications to validate the match or mismatch
state of DNA sequences. Through a labeling-free means, and from the evidence provided by specific
complementary and noncomplementary DNA sequences, the recognition capability of nano-reservoir can be down
to subnano-molar concentration (10−10 M).
The schamatic of nano-reservoir embedded micro-fluidic channel integrated with Raman microscopy as a biodetection platform for recognizing DNA hybridization.
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Research Express@NCKU - Articles Digest
Research Express@NCKU
Volume 27 Issue 8 - October 24, 2014
[ http://research.ncku.edu.tw/re/articles/e/20141024/2.html ]
Energetics and geographic distribution of elveproducing discharges
Alfred Bing-Chih Chen1,* , Han-Tzong Su2, Rue-Ron Hsu2
1
2
Institute of Space and Plasma Sciences, National Cheng Kung University
Department of Physics, National Cheng Kung University
[email protected]
Journal of Geophysical Research: Space Physics (2014) 119, 1381–1391.
I
n this paper, we use two data sets, the upgraded WWLLN lightning stroke data and the
ISUAL TLE data, to investigate the energetic and the geographic distributions of TLEproducing lightning. With a new algorithm to correct the ISUAL event time, the matching
ratio for finding the coincident events between these two data sets is found to be 37 - 44%,
which is higher than previous studies using NLDN data. The energy spectra of the lightning
strokes that induce the major TLEs, i.e., elve, sprite, and halo, reveal that, in general, the
energies of the TLE-producing strokes are at least an order of magnitude higher than that of typical lightning
strokes. The previous studies suggested that oceanic lightning is more intense than the land lightning. However,
the energy distribution of the elve-producing strokes exhibits no significant oceanic and land difference. These
results indicate that elves are indeed triggered by energetic lightning and that the production efficiency of elves
with respect to the stroke energy of the causative lightning is insensitive to the underlying landform. The lower
limit of the peak current to produce elves is inferred to be approximately 38 kA using the stroke energy to the peak
current conversion proposed in Hutchins et al. [2012]; this result agrees well with the result reported in BarringtonLeigh and Inan [1999] which has been derived using the selected elve events recorded in ground campaigns.
Analysis of the spatial correlation between the ISUAL elves and the WWLLN lightning indicates that the
geographic distribution of the ISUAL elves agrees well with that for the most energetic top 10% of the WWLLN
lightning strokes, better than that for the total lighting. We also found that elve occurrence rates in the regions of
reduced elves detection located at the behind-the-limb area may have been underestimated by at least a factor of 2
or 3, in part due to the failure in providing triggers to initiate ISUAL to store these events or the severe
atmospheric attenuation to elve emissions that may have rendered them indiscernible. Based on the uncorrected
occurrence rate of elves, Chen et al. [2008] reported that the global free electron contribution from elves is
approximately 1%, while the elve contribution to the free electron content above elve hot zones could be as high as
5%. After taking the contribution of the elve-depletion zone into account, the charge impact of elves to the lower
ionosphere could be much more significant.
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Research Express@NCKU - Articles Digest
Figure 1: Energy distribution of TLE-producing strokes: (a) elve, (b) sprite, and (c) halo. The gray curves represent
the energy distributions of the total WWLLN lightning reconstructed in this study.
Figure 2: Energy distribution of the elve-producing strokes (solid lines) and the total WWLLN strokes (dotted
lines) over the oceanic (blue) and the land (brown) areas.
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Research Express@NCKU - Articles Digest
Research Express@NCKU
Volume 27 Issue 8 - October 24, 2014
[ http://research.ncku.edu.tw/re/articles/e/20141024/3.html ]
Fee discounting and audit quality following audit
partner changes: Chinese evidence
Hua-Wei Huang1*, Kannan Raghunandan2, Ting-Chiao Huang3, & Jeng-Ren Chiou4
1, 3, 4
2
College of Management, National Cheng Kung University, Tainan , Taiwan, ROC
School of Accounting, Florida International University, FL, USA
[email protected]
The Accounting Review, July 2015.
M
any prior studies have shown that there is an initial year audit fee discount following
audit firm changes. One unique feature of the audit market in China is that two auditor
partners must sign the audit report. We find, using 9,684 observations during the years
2002-2011, that there is a significant initial year audit fee discount following an auditor
change only when both of the audit partners also are different than in the prior year. There
is no fee discount following an audit firm change if at least one of the signing partners is
with the new audit firm. Our analysis of abnormal accruals indicates that there is greater
earnings management following the auditor change only when there is an audit firm change coupled with audit
partner changes; further, a significant effect is found only when there is a fee discount accompanying such
simultaneous changes in both the audit firm and the signing partners. Thus, our results provide relevant empirical
evidence on issues of current interest to regulators—including, low-balling of initial year audit fees and identity of
the signing partner.
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Research Express@NCKU - Articles Digest
Research Express@NCKU
Volume 27 Issue 8 - October 24, 2014
[ http://research.ncku.edu.tw/re/articles/e/20141024/4.html ]
Gelsolin regulates cisplatin sensitivity in human headand-neck cancer
Pei-Wen Wang1, Mohammad R. Abedini2,3,4,5, Li-Xing Yang1, Ann-Ann Ding6, Daniel Figeys7,
Jang-Yang Chang8,9, Benjamin K. Tsang2,3,4,10, Dar-Bin Shieh1,6,11,12,*
1
Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
Department of Obstetrics & Gynaecology, University of Ottawa, Ottawa, Canada
3 Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, Canada
4 Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Canada
5 Cellular & Molecular Research Center, Department of Physiology and Pharmacology, Birjand
University of Medical Sciences, Birjand, Iran
6 Institute of Oral Medicine and Department of Stomatology, National Cheng Kung University
Hospital, College of Medicine, Tainan, Taiwan
7 Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems Biology
(OISB), University of Ottawa, Ottawa, Canada
8 Division of Hematology/Oncology, Department of Internal Medicine, National Cheng Kung
University Hospital, College of Medicine, Tainan, Taiwan
9 National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
10 Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, Canada
11 Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan
12 Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan
2
[email protected]
International Journal of Cancer. 2014 Apr 26. doi: 10.1002/ijc.28928.
G
elsolin (GSN) is a cytoskeleton-associated protein that regulates actin dynamic and is
aberrantly regulated in many tumor types. In oral cancer, GSN expression presented a
biphasic profile during cancer progression. High GSN expression conferred a poor
clinical outcome in patients with metastatic disease. Cisplatin is commonly used for
chemotherapy in patients with head-and-neck cancer (HNC). However, local recurrence
occurs in about 30–50% of cases and usually predicted a very poor prognosis.
Gelsolin expression is associated with HNC tumor recurrent and Cisplatin-resistance.
We analyzed the association between gelsolin expression and cisplatin resistance in HNC cell lines and tissue
samples from 58 cisplatin-treated HNC patients. The level of gelsolin protein expression is associated with
increased cisplatin resistance in HNC cells and indicated a strong association with refractory to chemotherapy in
HNC patients. Cisplatin-induced intact gelsolin (I-GSN) downregulation was associated with the cleavage of
gelsolin, mitochondrial membrane potential (Δψ) loss, and caspase-3 activation thus promoting the initiation of
apoptosis. The results raise the possibility that gelsolin may serve as an important regulator cisplatin-induced
apoptosis that lead to cytotoxicity of the cancer cells.
Modulation of gelsolin expression modified drug sensitivity in both HNC cell lines and xenograft in vivo
model.
Forced expression of I-GSN in chemosensitive cell (HONE1) increased cell viability and decreased
chemosensitivity upon cisplatin treatment. On the other hand, silencing gelsolin expression in chemoresistant cell
(HONE1-CIS6) facilitated cisplatin-induced apoptosis. Caspase-3 activation converted I-GSN to cleavage form
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Research Express@NCKU - Articles Digest
gelsolin (CL-GSN). Cisplatin-induced Δψ loss was significantly attenuated in cells that overexpressed gelsolin
(HONE1-I-GSN). Moreover, HNC xenografts tumor model established in SCID mice also supports this finding.
The tumors developed from HONE1-CIS6 and HONE1-I-GSN cells were resistant to cisplatin, but tumors from
HONE1 and HONE1-CIS6-shGSN cells responded to cisplatin treatment with a significant tumor volume loss over
time.
GSN–XIAP interaction and co-localization were attenuated in cisplatin-treated chemosensitive cells, but not
in chemoresistant cells
According to our yeast-two-hybrid screening, we discovered that GSN interact with intracellular intermediates Xlinked inhibitor of apoptosis protein (XIAP) and cross-talk with their signaling pathways. Such interaction may
direct cancer cell fate and make cancer cells sensitive or resistant to chemotherapy. Intact gelsolin (I-GSN) was
pro-survival in the presence of cisplatin by interacting with XIAP. In chemosensitive cells, cisplatin suppressed
GSN-XIAP interaction, promoted translocation of XIAP from the perinuclear region to the nucleus, and induced
apoptosis. In chemoresistant cells, gelsolin was highly expressed, and cisplatin had no significant effect on GSNXIAP interaction and apoptosis.
We conclude that gelsolin is important for chemoresistance in HNC and these findings suggest that the pathway
that gelsolin act on cancer chemoresistance in HNC may serve as an important new therapeutic target for HNC
cancer chemotherapy.
Figure legend: Chemoresistant head-and-neck cancer (HNC) cells (HONE1-CIS6) express more gelsolin (GSN)
than do their chemosensitive counterparts (HONE1). GSN-XIAP interactions were evident in both HONE1 and
HONE1-CIS6 cells in the absence of cisplatin. The GSN-XIAP interaction and co-localization were attenuated in
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Research Express@NCKU - Articles Digest
cisplatin-treated HONE1 cells, but not in HONE1-CIS6 cells. The critical influence of GSN in cancer
chemoresistance was evident in tumor-bearing mice with genetically modulated GSN expression levels. Tumors
developed from HONE1-CIS6 and HONE1-I-GSN (GSN overexpressing) cells were resistant to cisplatin, but
tumors developed from HONE1 and HONE1-CIS6-shGSN (GSN knockdown) cells responded to cisplatin
treatment with a significant loss in tumor volume.
Reference:
1. Sun HQ, Yamamoto M, Mejillano M, Yin HL. Gelsolin, a multifunctional actin regulatory protein. J Biol
Chem 1999; 274: 33179-82.
2. Shieh DB, Chen IW, Wei TY et al. Tissue expression of gelsolin in oral carcinogenesis progression and its
clinicopathological implications. Oral oncology 2006; 42: 599-606.
3. Fraser M, Bai T, Tsang BK. Akt promotes cisplatin resistance in human ovarian cancer cells through
inhibition of p53 phosphorylation and nuclear function. Int J Cancer 2008; 122: 534-46.
4. Wang PW, Abedini MR, Yang LX et al Gelsolin regulates cisplatin sensitivity in human head-and-neck
cancer. IJC 2014. doi: 10.1002/ijc.28928.
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