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David R. Smith

Bio: David R. Smith is an academic researcher from Duke University. The author has contributed to research in topics: Metamaterial & Antenna (radio). The author has an hindex of 110, co-authored 881 publications receiving 91683 citations. Previous affiliations of David R. Smith include Brunel University London & Princeton University.


Papers
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Journal ArticleDOI
TL;DR: In this article, the Chandrayaan-1 X-ray Spectrometer (C1XS) was used in a subsequent proton irradiation study involving eight swept charge devices (SCDs).
Abstract: This paper presents work carried out in support of swept-charge device (SCD) characterisation for the Chandrayaan-1 X-ray Spectrometer (C1XS) instrument. A brief overview of the C1XS instrument is presented, followed by a description of SCD structure and operation. The SCD test facility and method of device characterisation using two different drive sequencers to assess leakage current and spectroscopy performance (FWHM and noise at Mn Kα) are then described. The expected end-of-life (EOL) 10 MeV equivalent proton fluence for the SCDs of C1XS was modelled using Monte Carlo simulation software and used in a subsequent proton irradiation study involving eight SCDs. The irradiation study was carried out at the Kernfysisch Versneller Instituut (KVI) in the Netherlands and characterised the impact of 50% and 100% of the expected Chandrayaan-1 EOL proton fluence on the SCD operational characteristics. The radiation environment modelling, irradiation methodology and post-irradiation characterisation of the devices are presented in this paper and recommendations about the planned C1XS operational temperature and shielding are given.

18 citations

Proceedings ArticleDOI
TL;DR: The attributes of the EMCCD which make it useful for certain space instruments, particularly those which are photon starved, are discussed, and likely risks from the radiation expected in such instruments are explored.
Abstract: Electron multiplying CCD (EMCCD) technology has found important initial applications in low light surveillance and photon starved scientific instrumentation. This paper discusses the attributes of the EMCCD which make it useful for certain space instruments, particularly those which are photon starved, and explores likely risks from the radiation expected in such instruments.

18 citations

Proceedings ArticleDOI
21 Jul 2010
TL;DR: The paper provides the possible solutions for the challenges at hand and insight into the modelling work which will help the microwave engineering community to understand the behaviour of the microwave antennas in coupling media.
Abstract: This paper surveys the development of microwave medical imaging and the fundamental challenges associated with microwave antennas design for medical imaging applications. Different microwave antennas used in medical imaging applications such as monopoles, bow-tie, vivaldi and pyramidal horn antennas are discussed. The challenges faced when the latter used in medical imaging environment are detailed. The paper provides the possible solutions for the challenges at hand and also provides insight into the modelling work which will help the microwave engineering community to understand the behaviour of the microwave antennas in coupling media.

18 citations

Proceedings ArticleDOI
10 Apr 2016
TL;DR: A metal waveguide feed chain in a Ku-band scanning lens array antenna comprises five parts: two iris polarisers, two bend-feeds, and a central power combiner.
Abstract: A metal waveguide feed chain in a Ku-band scanning lens array antenna comprises 5 parts. These are: two iris polarisers, two bend-feeds, and a central power combiner. The combiner comprises a pair of septum polarisers and tee junctions. The feed chain generates a controllable, linear polarised E-field at each of two hemispherical lenses. Additive manufacturing was used to produce a copy of the power combiner and each bend-feed in copper plated plastic. In satellite receive-only trials at 10.7–12 GHz the plastic parts and metal parts performed equivalently.

18 citations

Journal ArticleDOI
TL;DR: A scoping review of altruism in general, clinical research, cancer, and HIV clinical research–including the HIV prevention, treatment, and cure-related research fields is conducted to better contextualize and understand how altruism is or could be operationalized in HIV cure- related research.
Abstract: Author(s): Dube, Karine; Perry, Kelly E; Mathur, Kushagra; Lo, Megan; Javadi, Sogol S; Patel, Hursch; Concha-Garcia, Susanna; Taylor, Jeff; Kaytes, Andy; Dee, Lynda; Campbell, Danielle; Kanazawa, John; Smith, David; Gianella, Sara; Auerbach, Judith D; Saberi, Parya; Sauceda, John A | Abstract: IntroductionThe question of what motivates people to participate in research is particularly salient in the HIV field. While participation in HIV research was driven by survival in the 1980's and early 1990's, access to novel therapies became the primary motivator with the advent of combination antiretroviral therapy (cART) in the late 1990s. In the HIV cure-related research context, the concept of altruism has remained insufficiently studied.MethodsWe conducted a scoping review to better contextualize and understand how altruism is or could be operationalized in HIV cure-related research. We drew from the fields of altruism in general, clinical research, cancer, and HIV clinical research-including the HIV prevention, treatment, and cure-related research fields.DiscussionAltruism as a key motivating factor for participation in clinical research has often been intertwined with the desire for personal benefit. The cancer field informs us that reasons for participation usually are multi-faceted and complex. The HIV prevention field offers ways to organize altruism-either by the types of benefits achieved (e.g., societal versus personal), or the origin of the values that motivate research participation. The HIV treatment literature reveals the critical role of clinical interactions in fostering altruism. There remains a dearth of in-depth knowledge regarding reasons surrounding research participation and the types of altruism displayed in HIV cure-related clinical research.ConclusionLessons learned from various research fields can guide questions which will inform the assessment of altruism in future HIV cure-related research.

18 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: A review of gold nanoparticles can be found in this article, where the most stable metal nanoparticles, called gold colloids (AuNPs), have been used for catalysis and biology applications.
Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

11,752 citations

Journal ArticleDOI
14 Aug 2003-Nature
TL;DR: By altering the structure of a metal's surface, the properties of surface plasmons—in particular their interaction with light—can be tailored, which could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved.
Abstract: Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons--in particular their interaction with light--can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.

10,689 citations

Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations