Modal interference in spiky nanoshells.

Hastings, Simon P,Qian, Zhaoxia,Swanglap, Pattanawit,Fang, Ying,Engheta, Nader,Park, So-Jung,Link, Stephan,Fakhraai, Zahra Optical Society of America 2015 Optics express Vol.23 No.9

<P>Near-field enhancement of the electric field by metallic nanostructures is important in non-linear optical applications such as surface enhanced Raman scattering. One approach to producing strong localization of the electric field is to couple a dark, non-radiating plasmonic mode with a broad dipolar resonator that is detectable in the far-field. However, characterizing or predicting the degree of the coupling between these modes for a complicated nanostructure can be quite challenging. Here we develop a robust method to solve the T-matrix, the matrix that predicts the scattered electric fields of the incident light, based on finite-difference time-domain (FDTD) simulations and least square fitting algorithms. This method allows us to simultaneously calculate the T-matrix for a broad spectral range. Using this method, the coupling between the electric dipole and quadrupole modes of spiky nanoshells is evaluated. It is shown that the built-in disorder in the structure of these nanoshells allows for coupling between the dipole modes of various orientations as well as coupling between the dipole and the quadrupole modes. A coupling strength of about 5% between these modes can explain the apparent interference features observed in the single particle scattering spectrum. This effect is experimentally verified by single particle backscattering measurements of spiky nanoshells. The modal interference in disordered spiky nanoshells can explain the origin of the spectrally broad quadrupole resonances that result in strong Quadrupole Enhanced Raman Scattering (QERS) in these nanoparticles.</P>

Cloning, sequencing and expression of dinoflagellate luciferase DNA from a marine alga, Gonyaulax polyedra

Woodland Hastings, J,Bae,Young Min 國立昌原大學校 基礎科學硏究所 1994 基礎科學硏究所論文集 Vol.6 No.-

The marine dinoflagellate, Gonyaulax polyedra emits light in a reaction involving the enzymatic oxidation of its tertrapyrrole luciferin by molecular oxygen; its luciferase (LCF) single chain has an estimated molecular mass of 130 kDa, and exhibits a circadian rhythm in its activity. A cDNA expression library in the λZAPII vector was constructed from the polyadenylated RNA isolated from the Gonyaulax cells during the early night phase, the time at which LCF synthesis is believed to be greatest. Of the approx. 1.2·105 phages from the library screened with antibody against Gonyaulax LCF, 13 positive plaques were obtained. The nucleotide sequences of two of the larger inserts (2.4 kb and 1.6kb in length), both carrying the poly(A) tail, were determined and found to be identical in the overlapping region. When expressed in Escherichia coli, both cDNA clones produced active luciferase. A Northern hybridization using the cDNA as a probe showed that the length of the lcf mRNA is approx. 4.1kb, sufficiently long to encode the 130 kDa LCF. Analyses of polymerase chain reaction products, prepared using both the cloned cDNA and Gonyaulax chromosomal DNA as templates, indicated that the cloned region of the luciferase gene does not carry any introns. This represents the first dinoflagellate luciferase to be cloned and sequenced; its deduced amino acid sequence bears no significant homologies with that of any other luciferase, or any other sequence in the data base. The nucleotide sequence has been submitted to Genbank, accession #LO4648.

Specific Purpose, Specific Focus: Effective Language Program Design

( Ashley J. Hastings ) 국제한국어교육학회 2008 국제한국어교육학회 학술대회논문집 Vol.2008 No.-

Informal Trade along the China-North Korea Border

Justin V. Hastings,Yaohui Wang 동아시아연구원 2018 Journal of East Asian Studies Vol.18 No.2

Why do Chinese traders along the China–North Korea border turn to informal trade, and what does it provide for them? Using a unique set of interviews with Chinese formal and informal traders operating in North Korea, we argue that the strategies of informal trade are a calculated response to certain types of risk. In doing so, we introduce a typology of risks and the mechanisms by which informal trade allows traders to mitigate those risks. Because informal traders bypass trade regulations and border checkpoints, they are able to mitigate risk more cheaply than formal traders in some cases and can overcome barriers that can cause failure in formal trade. Informal traders can thus maintain trade in many circumstances, including across North Korean personnel instability and policy reversals, Chinese sanctions enforcement, and delays and smuggling crackdowns on both sides of the border.

North Korea’s Lithium Research Networks and its Quest for a Hydrogen Bomb

( Justin V. Hastings ),( Haneol Lee ),( Robert Kelley ) 한국국방연구원 2018 The Korean Journal of Defense Analysis Vol.30 No.3

North Korea claims to have detonated a hydrogen bomb twice as of 2017. While any North Korean claim should be greeted with skepticism, it is important to assess whether North Korea actually has the technical capacity to deliver on its claims. If North Korea believes that it has the capacity to build a hydrogen bomb, this is likely to color its behavior and its negotiating strategy with the United States and other countries. Using new data about research subject areas and co-authoring networks taken from North Korean academic journals, we can gain entree into the opaque North Korean scientific establishment, and the progress (or lack thereof) it has made in processes related to the development of different types of nuclear weapons. We argue that a core group in North Korea has long had an interest in scientific research on lithium industrial processes that would be relevant to hydrogen bombs, although with detours. This interest has been ongoing since the mid-1990s, and peaked several years before North Korea’s first claimed hydrogen bomb test. Based on this assessment, it is within North Korea’s capability to produce a boosted fission device, and possibly a two-stage thermonuclear device. As a result, we conclude that North Korea is likely not bluffing when it says that its nuclear program has reached maturity.

교회 직무의 신학적 문제점

A. 헤이스팅스(Adrian Hastings) 광주가톨릭대학교 신학연구소 1971 神學展望 Vol.- No.13

놀라운 경이감, 예배, 그리고 복음증거: 신앙고백, 교리문답, 하나님의 선교 재고

토마스존해스팅스 ( Thomas John Hastings ) 한국장로교신학회 2018 장로교회와 신학 Vol.14 No.-

Raspberry-like Metamolecules Exhibiting Strong Magnetic Resonances

Qian, Zhaoxia,Hastings, Simon P.,Li, Chen,Edward, Brian,McGinn, Christine K,Engheta, Nader,Fakhraai, Zahra,Park, So-Jung American Chemical Society 2015 ACS NANO Vol.9 No.2

<P>We report a synthetic approach to produce raspberry-like plasmonic nanostructures with unusually strong magnetic resonances, termed raspberry-like metamolecules (raspberry-MMs). The synthesis based on the surfactant-assisted templated seed-growth method allows for the simultaneous one-step synthesis and assembly of well-insulated gold nanoparticles. The aromatic surfactant used for the syntheses forms a thin protective layer around the nanoparticles, preventing them from touching each other and making it possible to pack discrete nanoparticles at close distances in a single cluster. The resulting isotropic gold nanoparticle clusters (<I>i</I>.<I>e</I>., raspberry-MMs) exhibit unusually broad extinction spectra in the visible and near-IR region. Finite-difference time-domain (FDTD) modeling showed that the raspberry-MMs support strong magnetic resonances that contribute significantly to the broadband spectra. The strong magnetic scattering was also verified by far-field scattering measurements, which show that in the near-IR region the magnetic dipole resonance can be even stronger than the electric dipole resonance in these raspberry-MMs. Structural parameters such as the size and the number of gold nanoparticles composing raspberry-MMs can be readily tuned in our synthetic method. A series of syntheses with varying structure parameters, along with FDTD modeling and mode analyses of corresponding model structures, showed that the close packing of a large number of metal nanoparticles in raspberry-MMs is responsible for the unusually strong magnetic resonances observed here.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-2/nn5050678/production/images/medium/nn-2014-050678_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5050678'>ACS Electronic Supporting Info</A></P>

Perception of Time-Varying Tonal Components

Kyoung Hoon Lee,Aaron Hastings,Patricia Davies,Aimee Surprenant 한국소음진동공학회 2003 한국소음진동공학회 국제학술대회논문집 Vol.2003 No.8

Transcriptional Regulation of TCF/LEF and PPARγ by Daidzein and Genistein in 3T3-L1 Preadipocytes

Jeremy E. Davis,Darcie Hastings 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.8

Adipogenesis is central to adipose tissue plasticity and lipid homeostasis. Regulation of adipogenic signaling by phytoestrogens has been implicated as a potential therapeutic strategy for obesity-related disease. However, it remains unclear how these compounds directly impact transcriptional control of adipogenesis. As such, the focus of this study was to determine how daidzein and genistein effect transcriptional activation of peroxisome proliferator-activated receptor gamma (PPARγ) and TCF/LEF in 3T3-L1 preadipocytes. We also measured the effect of estrogen receptor (ER) knockdown on expression of preadipocyte (i.e., Pref1) and adipocyte (i.e., Fabp4) markers in cells treated with varying concentrations of daidzein or genistein (i.e., 10−4, 10−7, and 10−10). Our findings showed that activation of TCF/LEF was induced by daidzein and genistein in undifferentiated and differentiated 3T3-L1 preadipocytes. Conversely, PPARγ reporter activity was inhibited by genistein, which corresponded with a reduction in cell diameter of differentiated preadipocytes. Daidzein increased cell diameter, as well as reduced Pref1 abundance in undifferentiated cells. Although small, there was a significant reduction in Pref1 and Fabp4 abundance in undifferentiated cells with ERα and ERβ knockdown. However, reduced abundance of ER subtypes exhibited no significant effect on phytoestrogen treatment. Collectively, our findings show phytoestrogens distinctly regulate adipogenic transcription factors and thus, may have implications for adipose dysfunction and obesity-related disease.