1,193 research outputs found
Thermodynamic characterization of specific interactions between the human Lon protease and G-quartet DNA
Lon is an ATP-powered protease that binds DNA. However, the function of DNA binding by Lon remains elusive. Studies suggest that human Lon (hLon) binds preferentially to a G-rich single-stranded DNA (ssDNA) sequence overlapping the light strand promoter of mitochondrial DNA. This sequence is contained within a 24-base oligonucleotide referred to as LSPas. Here, we use biochemical and biophysical approaches to elucidate the structural properties of ssDNAs bound by hLon, as well as the thermodynamics of DNA binding by hLon. Electrophoretic mobility shift assay and circular dichroism show that ssDNAs with a propensity for forming parallel G-quartets are specifically bound by hLon. Isothermal titration calorimetry demonstrates that hLon binding to LSPas is primarily driven by enthalpy change associated with a significant reduction in heat capacity. Differential scanning calorimetry pinpoints an excess heat capacity upon hLon binding to LSPas. By contrast, hLon binding to an 8-base G-rich core sequence is entropically driven with a relatively negligible change in heat capacity. A considerable enhancement of thermal stability accompanies hLon binding to LSPas as compared to the G-rich core. Taken together, these data support the notion that hLon binds G-quartets through rigid-body binding and that binding to LSPas is coupled with structural adaptation
Zero-temperature magnetism in the periodic Anderson model in the limit of large dimensions
We study the magnetism in the periodic Anderson model in the limit of large
dimensions by mapping the lattice problem into an equivalent local impurity
self-consistent model. Through a recently introduced algorithm based on the
exact diagonalization of an effective cluster hamiltonian, we obtain solutions
with and without magnetic order in the half-filled case. We find the exact
AFM-PM phase boundary which is shown to be of order and obeys
We calculate the local staggered moments and the
density of states to gain insights on the behavior of the AFM state as it
evolves from itinerant to a local-moment magnetic regimeComment: 9 pages + 9 figures, to appear in Phys. Rev. B, 1 Sept. 1995 issu
Room-temperature biphoton source with a spectral brightness near the ultimate limit
The biphotons, generated from a hot atomic vapor via the process of
spontaneous four-wave mixing (SFWM), have the following merits: stable and
tunable frequencies as well as linewidth. Such merits are very useful in the
applications of long-distance quantum communication. However, the hot-atom SFWM
biphoton sources previously had far lower values of generation rate per
linewidth, i.e., spectral brightness, as compared with the sources of biphotons
generated by the spontaneous parametric down conversion (SPDC) process. Here,
we report a hot-atom SFWM source of biphotons with a linewidth of 960 kHz and a
generation rate of 3.7 pairs/s. The high generation rate,
together with the narrow linewidth, results in a spectral brightness of
3.8 pairs/s/MHz, which is 17 times of the previous best result
with atomic vapors and also better than all known results with all kinds of
media. The all-copropagating scheme together with a large optical depth (OD) of
the atomic vapor is the key improvement, enabling the achieved spectral
brightness to be about one quarter of the ultimate limit. Furthermore, this
biphoton source had a signal-to-background ratio (SBR) of 2.7, which violated
the Cauchy-Schwartz inequality for classical light by about 3.6 folds. Although
an increasing spectral brightness usually leads to a decreasing SBR, our
systematic study indicates that both of the present spectral brightness and SBR
can be enhanced by further increasing the OD. This work demonstrates a
significant advancement and provides useful knowledge in the quantum technology
using photons
Life, death, and spirituality: A conceptual analysis for educational research development
Life education, also known as life and death education, is an important subject in Taiwan. Life education is more than just the study of a person's development throughout the lifespan (e.g., cognitive development). Within the learning and sociocultural contexts of Taiwan, interestingly, the study of life and death education is concerned with the premise of the promotion and fulfillment of life qualities (e.g., a person's state of contentment), and the meaningful understanding of the nature of death. To facilitate appreciation and deep, meaningful understanding of the subject, and to emphasize its uniqueness, educators have included in their teaching the importance of Eastern-derived philosophical beliefs and religious faiths (e.g., Buddhism). For example, relatively significant in its emphasis, the teaching of this subject involves detailed examination of theoretical accounts of spiritual cultivation and its positive effect on a person's interpretation and enlightenment of life wisdom.
The study of life education, or life and death education, we contend, is of significance as it provides life-related insights and theoretical understanding into the intricate nature of life and death. One notable aspect of the subject entails a person's acquired life wisdom, which in turn may shape his/her life practice on a daily basis (e.g., the proactive engagement in Buddhist meditation). Importantly, the study of life education may assist individuals with their coping of grief, and to approach death with a sense of peace, calmness, and dignity. In this analysis, coupled with Buddhist faith (or any other religious faith for that matter) and facilitated by spiritual cultivation (e.g., the belief in the notion of transcendence experience), a person may overcome grief by believing in the possibility that there is some form of post-death experience and the presence of a loved one's spiritual being. Given this emphasis, we consider an important focus for discussion in this article: to explore the significance of life and death education and to determine how its ‘positive nature’ could potentially yield two comparable implications for development: (i) to engage in appropriate pedagogical practices that would encourage and promote the study of life and death education, and (ii) to advance innovative research inquiries, theoretical, methodological, and/or empirical, which could highlight the significance of life education for life purposes (e.g., the significance of Chinese ideograms, such as 孝)
Tenfold Magnetoconductance in a Non-Magnetic Metal Film
We present magnetoconductance (MC) measurements of homogeneously disordered
Be films whose zero field sheet conductance (G) is described by the
Efros-Shklovskii hopping law . The low field
MC of the films is negative with G decreasing 200% below 1 T. In contrast the
MC above 1 T is strongly positive. At 8 T, G increases 1000% in perpendicular
field and 500% in parallel field. In the simpler parallel case, we observe {\em
field enhanced} variable range hopping characterized by an attenuation of
via the Zeeman interaction.Comment: 9 pages including 5 figure
International Veterinary Epilepsy Task Force consensus proposal: Medical treatment of canine epilepsy in Europe
In Europe, the number of antiepileptic drugs (AEDs) licensed for dogs has grown considerably over the last years. Nevertheless, the same questions remain, which include, 1) when to start treatment, 2) which drug is best used initially, 3) which adjunctive AED can be advised if treatment with the initial drug is unsatisfactory, and 4) when treatment changes should be considered. In this consensus proposal, an overview is given on the aim of AED treatment, when to start long-term treatment in canine epilepsy and which veterinary AEDs are currently in use for dogs. The consensus proposal for drug treatment protocols, 1) is based on current published evidence-based literature, 2) considers the current legal framework of the cascade regulation for the prescription of veterinary drugs in Europe, and 3) reflects the authors’ experience. With this paper it is aimed to provide a consensus for the management of canine idiopathic epilepsy. Furthermore, for the management of structural epilepsy AEDs are inevitable in addition to treating the underlying cause, if possible
- …