278 research outputs found
Analysis of Floquet formulation of time-dependent density-functional theory
Floquet formulation of time-dependent density-functional theory is revisited
in light of its recent criticism [Maitra and Burke, Chem. Phys. Lett. 359
(2002), 237]. It is shown that Floquet theory is well founded and its criticism
has overlooked important points of both the Runge-Gross formalism and Floquet
formulation itself. We substantiate our analysis by examples similar to that
considered by Maitra and Burke.Comment: 17 pages, 2 figures. accepted for publication in "Chemical Physics
Letters
ASPIRE: Activity Safety Planning and Infection Risk Estimator for COVID-19
The COVID-19 pandemic has prompted multiple researchers to investigate this domain since 2020. One aspect being explored in this topic is the available tools in assisting the public in estimating virus risks. Due to the limited availability of the tools, Jimenez and Peng created the Aerosol Transmission Estimator, which is a peer-reviewed risk estimator that garnered positive reception. The tool is encoded in Google sheets. However, people may find it difficult to use due to the terminologies and information presented in that sheet. To solve this, MyCOVIDRisk, a user-friendly website was built for this estimator, but it is only configured for the United States setting. Accordingly, this study created a website called ASPIRE using Jimenez and Peng’s estimator to evaluate the risk and MyCOVIDRisk as reference for the interface design. ASPIRE is configured for the Philippine setting. The usability of ASPIRE was evaluated through surveys and interviews using the System Usability Scale (SUS) and content analysis. The SUS used for measuring usability yielded a grade of A—above average. The overall feedback of the respondents was mostly positive. Issues and suggestions raised by the respondents were addressed. Further research is needed to improve ASPIRE, determine its usability to medical professionals, learn its accessibility and inclusivity to users, and identify its impact on the Philippine community. Overall, this study shows how a COVID-19 risk estimation website was developed and improved based on user evaluation, which can be used as a reference in creating e-health tools
D-β-Hydroxybutyrate rescues mitochondrial respiration and mitigates features of Parkinson disease
This is the published version. Copyright 2003 : American Society for Clinical Investigation.Parkinson disease (PD) is a neurodegenerative disorder characterized by a loss of the nigrostriatal dopaminergic neurons accompanied by a deficit in mitochondrial respiration. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that causes dopaminergic neurodegeneration and a mitochondrial deficit reminiscent of PD. Here we show that the infusion of the ketone body D-β-hydroxybutyrate (DβHB) in mice confers partial protection against dopaminergic neurodegeneration and motor deficits induced by MPTP. These effects appear to be mediated by a complex II–dependent mechanism that leads to improved mitochondrial respiration and ATP production. Because of the safety record of ketone bodies in the treatment of epilepsy and their ability to penetrate the blood-brain barrier, DβHB may be a novel neuroprotective therapy for PD
Metagenomic analysis of DNA viruses with targeted sequence capture of canine lobular orbital adenomas and normal conjunctiva
Our study aims are: (1) to evaluate phenotypically normal canine conjunctival and orbital tissue and tissue from canine lobular orbital adenomas (CLOAs) for the presence of viral genomic material and (2) phylogenetically classify detected DNA viruses to determine if a DNA virus is associated with CLOAs. A total of 31 formalin fixed paraffin embedded CLOA tissue samples, 4 papillomas or sarcoid, and 10 fresh clinically normal conjunctival tissues were included in this study. Genomic DNA was isolated from all samples and sequencing libraries were prepared. The libraries were molecularly indexed and pooled and viral DNA was enriched via targeted sequence capture utilizing ViroCap. The libraries were sequenced on the Illumina HiSeq platform and compared to known viral DNA reference genomes to identify viral DNA. Carnivore parvovirus was identified in 6.4% and 20% of CLOA tissue and normal conjunctival samples, respectively. This study showed that conjunctival tissue from healthy dogs and CLOAs uncommonly harbor DNA viruses, and no DNA virus was associated with these tumors. Further studies are needed to evaluate the etiologic cause of CLOAs
Kilohertz-driven Bose-Einstein condensates in optical lattices
We analyze time-of-flight absorption images obtained with dilute
Bose-Einstein con-densates released from shaken optical lattices, both
theoretically and experimentally. We argue that weakly interacting, ultracold
quantum gases in kilohertz-driven optical potentials constitute equilibrium
systems characterized by a steady-state distri-bution of Floquet-state
occupation numbers. Our experimental results consistently indicate that a
driven ultracold Bose gas tends to occupy a single Floquet state, just as it
occupies a single energy eigenstate when there is no forcing. When the driving
amplitude is sufficiently high, the Floquet state possessing the lowest mean
energy does not necessarily coincide with the Floquet state connected to the
ground state of the undriven system. We observe strongly driven Bose gases to
condense into the former state under such conditions, thus providing nontrivial
examples of dressed matter waves.Comment: 36 pages, 3 figures, Advance Atomic Molecular Physics in pres
Multiphoton Ionization as Time-Dependent Tunneling
A new semiclassical approach to ionization by an oscillating field is
presented. For a delta-function atom, an asymptotic analysis is performed with
respect to a quantity h, defined as the ratio of photon energy to ponderomotive
energy. This h appears formally equivalent to Planck's constant in a suitably
transformed Schroedinger equation and allows semiclassical methods to be
applicable. Systematically, a picture of tunneling wave packets in complex time
is developped, which by interference account for the typical ponderomotive
features of ionization curves. These analytical results are then compared to
numerical simulations and are shown to be in good agreement.Comment: 36 pages (also printable half size), uuencoded compressed tarred
Latex file with 9 Postscript figures included automaticall
Quantum Statistics and Entanglement of Two Electromagnetic Field Modes Coupled via a Mesoscopic SQUID Ring
In this paper we investigate the behaviour of a fully quantum mechanical
system consisting of a mesoscopic SQUID ring coupled to one or two
electromagnetic field modes. We show that we can use a static magnetic flux
threading the SQUID ring to control the transfer of energy, the entanglement
and the statistical properties of the fields coupled to the ring. We also
demonstrate that at, and around, certain values of static flux the effective
coupling between the components of the system is large. The position of these
regions in static flux is dependent on the energy level structure of the ring
and the relative field mode frequencies, In these regions we find that the
entanglement of states in the coupled system, and the energy transfer between
its components, is strong.Comment: 15 pages, 19 figures, Uploaded as implementing a policy of arXiving
old paper
The growing needs of genetic counselling—Feasibility in utilization of tele-genetic counselling in Asia and Hong Kong
The need for the expansion of genomic services has been at a record time high in the past decade. As technological advancement continues to strengthen the entire genetic and genomic pipeline and clinical operational workflow, the major challenge remains to be the speed of workforce development to meet service growth. In particular, the international expansion of genetic counselling (GC) services has been a topic of interest for the past few years. GC is an emerging profession in most of Asia, and in many countries the profession of GC often refers to physicians or front-line health workers with expertise in genetics to provide GC services rather than being a specific independent profession. As genetic and genomic services, especially pre-test and post-test GC, expand globally, the need to tackle the longstanding obstacles of GC personnel shortage and funding issues must not be overlooked. There is an urgent need internationally, and especially in Asia, where GC profession is comparatively less well-established, to seek alternative approaches to meet service demand. The present review examines the global development and feasibility of tele-genetics and tele-genetic counselling (TGC), and serves as the foundation to explore a possible roadmap in Hong Kong via the Hong Kong Genome Project
Discovery of Samarium, Europium, Gadolinium, and Terbium Isotopes
Currently, thirty-four samarium, thirty-four europium, thirty-one gadolinium,
and thirty-one terbium isotopes have been observed and the discovery of these
isotopes is discussed here. For each isotope a brief synopsis of the first
refereed publication, including the production and identification method, is
presented.Comment: To be published in At. Data Nucl. Data Table
Identification of flavone phytoalexins and a pathogen-inducible flavone synthase II gene (SbFNSII) in sorghum
Following inoculation with the anthracnose pathogen Colletotrichum sublineolum, seedlings of the sorghum resistant cultivar SC748-5 showed more rapid and elevated accumulation of luteolin than the susceptible cultivar BTx623. On the other hand, apigenin was the major flavone detected in infected BTx623 seedlings. Luteolin was demonstrated to show stronger inhibition of spore germination of C. sublineolum than apigenin. Because of their pathogen-inducible and antifungal nature, both flavone aglycones are considered sorghum phytoalexins. The key enzyme responsible for flavone biosynthesis has not been characterized in monocots. A sorghum pathogen-inducible gene encoding a cytochrome P450 protein (CYP93G3) in the uncharacterized CYP93G subfamily was identified. Transgenic expression of the P450 gene in Arabidopsis demonstrated that the encoded protein is a functional flavone synthase (FNS) II in planta. The sorghum gene was then termed SbFNSII. It is a single-copy gene located on chromosome 2 and the first FNSII gene characterized in a monocot. Metabolite analysis by liquid chromatography–tandem mass spectrometry (LC-MS/MS) in precursor ion scan mode revealed the accumulation of 2-hydroxynaringenin and 2-hydroxyeriodictyol hexosides in the transgenic Arabidopsis plants. Hence, SbFNSII appears to share a similar catalytic mechanism with the licorice and Medicago truncatula FNSIIs (CYP93B subfamily) by converting flavanones to flavone through the formation of 2-hydroxyflavanones
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