1,413 research outputs found
Monograph of Chinese Aceraceae
The purpose of this work is to summarize our present
knowledge of the Acereous plants of Chinai, Since Pax
published his last monograph of Aceraceae2 in 1902, the
multiplicity of new species and the huge collections of
material which are not easily identified, have particularly emphasized the somewhat pressing requirement for a critical review and the necessity for supplementary descriptions and special notes.This work was continued over a period of more than
five years. During this time various herbaria were
visited where type- specimens and numerous collections
were carefully examined. The main work has been done
at the Royal Botanic Garden, Edinburgh. I am greatly
indebted to Professor Sir William Wright Smith, who
has given me continual encouragement during the course
of my work. My best thanks are also due to Dr. J. M.
Cowan for invaluable suggestions and criticism; to Mr.
W. E. Evans for special arrangement of material; to Cdr.
J. T. Johnstone for assistance in gathering literature,
and to Dr, H. R. Fletcher for his critical reading of
some parts of the manuscript. I should like also to
tender my sincere thanks to Professor S. S. Chien of the
Biological Laboratory of the Science Society of China,
Nanking, under whose supervision I laid the basis of my
work there. I am very obliged to Professor A. Rehder of the Arnold Arboretum, Jamaica Plain, Massachussetts,
U.S.A.; Professor H. Handel -Mazzetti of the Botanic
Institute and Garden, Vienna, Austria; Professor H.
H. Hu of the Fan Memorial Institute of Biology, Peiping;
Professor W. Y. Chun of the Botanic Institute of Sun - Yatsen University, Canton; and to Professor F. P.
Metcalf of the Lingnan University, Canton, for their
kindness in sending me material, and valuable suggestions
on some special problems. My warmest thanks are also
due to the authorities of various herbaria - too numerous
to be mentioned individually - who sent specimens on
loan. I wish to express my special acknowledgment to
Mr. J. Ramsbottom of the Department of Botany, British
Museum (Natural History, London; to Sir Arthur W. Hill
and Dr. A. D. Cotton of the Royal Botanic Gardens, Kew,
England; to Professor L. Diels and Professor R. Pilger
of the Botanic Museum, Berlin -Dahlem, Germany; to
Professor F. Pax and Professor H. Winkler of the Botanic
Institute, Breslau, Germany; to Professor K. Sussenguth
of the Botanic Garden, Munich, Germany; to Dr. K. Keissler
of the Natural History Museum, Vienna, Austria; to
Professor F. Knoll of the Botanic Institute and Garden,
Vienna, Austria; to Professor G. Negri and Professor A.
Messeri of the Botanic Museum, Florence, Italy; and to
Professor H. Humbert of the Natural History Museum,
Paris, France, for their courtesy in granting me the privilege of examining specimens in their herbari
STAR-RIS-Assisted-Full-Duplex Jamming Design for Secure Wireless Communications System
Physical layer security (PLS) technologies are expected to play an important
role in the next-generation wireless networks, by providing secure
communication to protect critical and sensitive information from illegitimate
devices. In this paper, we propose a novel secure communication scheme where
the legitimate receiver use full-duplex (FD) technology to transmit jamming
signals with the assistance of simultaneous transmitting and reflecting
reconfigurable intelligent surface (STARRIS) which can operate under the energy
splitting (ES) model and the mode switching (MS) model, to interfere with the
undesired reception by the eavesdropper. We aim to maximize the secrecy
capacity by jointly optimizing the FD beamforming vectors, amplitudes and phase
shift coefficients for the ESRIS, and mode selection and phase shift
coefficients for the MS-RIS. With above optimization, the proposed scheme can
concentrate the jamming signals on the eavesdropper while simultaneously
eliminating the self-interference (SI) in the desired receiver. To tackle the
coupling effect of multiple variables, we propose an alternating optimization
algorithm to solve the problem iteratively. Furthermore, we handle the
non-convexity of the problem by the the successive convex approximation (SCA)
scheme for the beamforming optimizations, amplitudes and phase shifts
optimizations for the ES-RIS, as well as the phase shifts optimizations for the
MS-RIS. In addition, we adopt a semi-definite relaxation (SDR) and Gaussian
randomization process to overcome the difficulty introduced by the binary
nature of mode optimization of the MS-RIS. Simulation results validate the
performance of our proposed schemes as well as the efficacy of adapting both
two types of STAR-RISs in enhancing secure communications when compared to the
traditional selfinterference cancellation technology.Comment: 12 pages, 7 figure
Poly[diaqua-μ2-isonicotinato-μ2-oxalato-terbium(III)]
In the crystal structure of the title complex, [Tb(C6H4NO2)(C2O4)(H2O)2]n, the TbIII cation is coordinated by four O atoms from two oxalate ligands, two O atoms from two isonicotinate ligands and two O atoms from water molÂecules within a distorted square–antiÂprismatic coordination. The TbIII cation, the isonicotinate anion and the two crystallographically independent water molÂecules occupy general positions, whereas one of the two crystallographically independent oxalate anions is located on a center of inversion, and the second oxalate anion is located on a twofold rotation axis. The TbIII cations are linked by the oxalate and isonicotinate anions into layers, which are connected via interÂmolecular hydrogen-bonding and π–π stacking [with centroid-to-centroid distances of 3.509 (2) and 3.343 (3) Å] interÂactions into a three-dimensional network
Mechanistic insight into how multidrug resistant Acinetobacter baumannii response regulator AdeR recognizes an intercistronic region
AdeR-AdeS is a two-component regulatory system, which controls expression of the adeABC efflux pump involved in Acinetobacter baumannii multidrug resistance. AdeR is a response regulator consisting of an N-terminal receiver domain and a C-terminal DNA-binding-domain. AdeR binds to a direct-repeat DNA in the intercistronic region between adeR and adeABC. We demonstrate a markedly high affinity binding between unphosphorylated AdeR and DNA with a dissociation constant of 20 nM. In addition, we provide a 2.75 angstrom crystal structure of AdeR DNA-binding-domain complexed with the intercistronic DNA. This structure shows that the alpha 3 and beta hairpin formed by beta 5-beta 6 interacts with the major and minor groove of the DNA, which in turn leads to the introduction of a bend. The AdeR receiver domain structure revealed a dimerization motif mediated by a gearwheel-like structure involving the D108F109-R122 motif through cation pi stack interaction. The structure of AdeR receiver domain bound with magnesium indicated a conserved Glu19Asp20-Asp63 magnesium-binding motif, and revealed that the potential phosphorylation site Asp63(OD1) forms a hydrogen bond with Lys112. We thus dissected the mechanism of how AdeR recognizes the intercistronic DNA, which leads to a diverse mode of response regulation. Unlocking the AdeRS mechanism provides ways to circumvent A. baumannii antibiotic resistance
The Incremental Diagnostic Performance of Coronary Computed Tomography Angiography Added to Myocardial Perfusion Imaging in Patients with Intermediate-to-High Cardiovascular Risk
Purpose: Several studies have suggested that a combined approach of stress myocardial perfusion imaging (MPI) and coronary computed tomography angiography (CCTA) can provide diagnostic results with excellent accuracy. We aimed to explore whether the addition of CCTA to stress MPI provides incremental diagnostic value in intermediate-to-high cardiovascular risk patients. Methods: A total of 106 consecutive patients (93 male, 65 ± 10.4 years) underwent coronary artery calcium scoring (CACS), CCTA and 201 Thallium stress MPI before coronary angiography was reviewed. Thirty-seven patients (34.9%) had a history of proven coronary artery disease (CAD) or revascularization procedures, and four had documented non-significant CAD (3.8%). The remaining patients consisted of 17 (16.0%) classified as intermediate, and 48 (45.3%) as the high-risk groups. Results: Obstructive CAD was diagnosed by invasive coronary angiography in 88 patients with 161 vessels. The sensitivity and specificity in a patient-based analysis for obstructive CAD were 99% and 17% for CCTA, 80% and 50% for MPI and 91% and 67% for the combined method, respectively. The per-vessel diagnostic sensitivity and specificity were 95% and 54% for CCTA, 59% and 75% for MPI and 84% and 76% for the combined method. There were significant differences (p < 0.05) when comparing the combined method with MPI or CCTA by areas under the curve in a patient-or vessel-based analysis. However, CACS of 400 or more could not further stratify the patients with obstructive CAD. Conclusions: CCTA, not CACS, provided additional diagnostic values to stress MPI in patients with intermediateto-high cardiovascular risk
Generation of a Homozygous Knock-in Human Embryonic Stem Cell Line Expressing Meos4b-tagged Ctr1
Copper transporter 1 (CTR1) is the major membrane protein responsible for cellular copper (Cu) uptake and mediates cellular copper homeostasis. To elucidate CTR1\u27s behavior using imaging approaches, we generated a homozygous knock-in human embryonic stem cell (hESC) clone expressing photoconvertible fluorescence protein mEos4b-tagged endogenous CTR1 using CRISPR-Cas9 mediated homologous recombination. The engineered cells express functional CTR1-mEos4b fusion and have normal stem cell morphology. They remain pluripotent and can be differentiated into all three germ layers in vitro. This resource allows the study of CTR1 at an endogenous level in different cellular contexts using microscopy
Family-Based Bivariate Association Tests for Quantitative Traits
The availability of a large number of dense SNPs, high-throughput genotyping and computation methods promotes the application of family-based association tests. While most of the current family-based analyses focus only on individual traits, joint analyses of correlated traits can extract more information and potentially improve the statistical power. However, current TDT-based methods are low-powered. Here, we develop a method for tests of association for bivariate quantitative traits in families. In particular, we correct for population stratification by the use of an integration of principal component analysis and TDT. A score test statistic in the variance-components model is proposed. Extensive simulation studies indicate that the proposed method not only outperforms approaches limited to individual traits when pleiotropic effect is present, but also surpasses the power of two popular bivariate association tests termed FBAT-GEE and FBAT-PC, respectively, while correcting for population stratification. When applied to the GAW16 datasets, the proposed method successfully identifies at the genome-wide level the two SNPs that present pleiotropic effects to HDL and TG traits
Insights into Chinese perspectives on do-not-resuscitate (DNR) orders from an examination of DNR order form completeness for cancer patients
PURPOSE: Discussing end-of-life care with patients is often considered taboo, and signing a do-not-resuscitate (DNR) order is difficult for most patients, especially in Chinese culture. This study investigated distributions and details related to the signing of DNR orders, as well as the completeness of various DNR order forms. METHODS: Retrospective chart reviews were performed. We screened all charts from a teaching hospital in Taiwan for patients who died of cancer during the period from January 2010 to December 2011. A total of 829 patient records were included in the analysis. The details of the DNR order forms were recorded. RESULTS: The DNR order signing rate was 99.8Â %. The percentage of DNR orders signed by patients themselves (DNR-P) was 22.6Â %, while the percentage of orders signed by surrogates (DNR-S) was 77.2Â %. The percentage of signed DNR forms that were completely filled out was 78.4Â %. The percentage of DNR-S forms that were completed was 81.7Â %, while the percentage of DNR-P forms that were completely filled out was only 67.6Â %. CONCLUSION: Almost all the cancer patients had a signed DNR order, but for the majority of them, the order was signed by a surrogate. Negative attitudes of discussing death from medical professionals and/or the family members of patients may account for the higher number of signed DNR-S orders than DNR-P orders. Moreover, early obtainment of signed DNR orders should be sought, as getting the orders earlier could promote the quality of end-of-life care, especially in non-oncology wards
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