474 research outputs found
Entangled SU(2) and SU(1,1) coherent states
Entangled SU(2) and SU(1,1) coherent states are developed as superpositions
of multiparticle SU(2) and SU(1,1) coherent states. In certain cases, these are
coherent states with respect to generalized su(2) and su(1,1) generators, and
multiparticle parity states arise as a special case. As a special example of
entangled SU(2) coherent states, entangled binomial states are introduced and
these entangled binomial states enable the contraction from entangled SU(2)
coherent states to entangled harmonic oscillator coherent states. Entangled
SU(2) coherent states are discussed in the context of pairs of qubits. We also
introduce the entangled negative binomial states and entangled squeezed states
as examples of entangled SU(1,1) coherent states. A method for generating the
entangled SU(2) and SU(1,1) coherent states is discussed and degrees of
entanglement calculated. Two types of SU(1,1) coherent states are discussed in
each case: Perelomov coherent states and Barut-Girardello coherent states.Comment: 31 pages, no figure
Non-classical properties and algebraic characteristics of negative binomial states in quantized radiation fields
We study the nonclassical properties and algebraic characteristics of the
negative binomial states introduced by Barnett recently. The ladder operator
formalism and displacement operator formalism of the negative binomial states
are found and the algebra involved turns out to be the SU(1,1) Lie algebra via
the generalized Holstein-Primarkoff realization. These states are essentially
Peremolov's SU(1,1) coherent states. We reveal their connection with the
geometric states and find that they are excited geometric states. As
intermediate states, they interpolate between the number states and geometric
states. We also point out that they can be recognized as the nonlinear coherent
states. Their nonclassical properties, such as sub-Poissonian distribution and
squeezing effect are discussed. The quasiprobability distributions in phase
space, namely the Q and Wigner functions, are studied in detail. We also
propose two methods of generation of the negative binomial states.Comment: 17 pages, 5 figures, Accepted in EPJ
Phonon-assisted tunneling in asymmetric resonant tunneling structures
Based on the dielectric continuum model, we calculated the phonon assisted
tunneling (PAT) current of general double barrier resonant tunneling structures
(DBRTSs) including both symmetric and antisymmetric ones. The results indicate
that the four higher frequency interface phonon modes (especially the one which
peaks at either interface of the emitter barrier) dominate the PAT processes,
which increase the valley current and decrease the PVR of the DBRTSs. We show
that an asymmetric structure can lead to improved performance.Comment: 1 paper and 5 figure
Interferencing intensity in two Bose-Einstein condensates with Josephson-like coupling
Abstract We derive a general expression for interferencing intensity in two Bose -Einstein condensates with Josephson-like coupling when the two Bose -Einstein condensates are initially in arbitrary quantum pure states. The expression can be used to numerically calculate the intensity. As examples, we study the time behaviors of the intensity when the two Bose -Einstein condensates are initially in coherent states, Fock states, and squeezed states, respectively. c 1999 Elsevier Science B.V. All rights reserved. PAC
Evolutional selection of a combinatorial phage library displaying randomly-rearranged various single domains of immunoglobulin (Ig)-binding proteins (IBPs) with four kinds of Ig molecules
<p>Abstract</p> <p>Background</p> <p>Protein A, protein G and protein L are three well-defined immunoglobulin (Ig)-binding proteins (IBPs), which show affinity for specific sites on Ig of mammalian hosts. Although the precise functions of these molecules are not fully understood, it is thought that they play an important role in pathogenicity of bacteria. The single domains of protein A, protein G and protein L were all demonstrated to have function to bind to Ig. Whether combinations of Ig-binding domains of various IBPs could exhibit useful novel binding is interesting.</p> <p>Results</p> <p>We used a combinatorial phage library which displayed randomly-rearranged various-peptide-linked molecules of D and A domains of protein A, designated PA(D) and PA(A) respectively, B2 domain of protein G (PG) and B3 domain of protein L (PL) for affinity selection with human IgG (hIgG), human IgM (hIgM), human IgA (hIgA) and recombinant hIgG1-Fc as bait respectively. Two kinds of novel combinatorial molecules with characteristic structure of PA(A)-PG and PA(A)-PL were obtained in hIgG (hIgG1-Fc) and hIgM (hIgA) post-selection populations respectively. In addition, the linking peptides among all PA(A)-PG and PA(A)-PL structures was strongly selected, and showed interestingly divergent and convergent distribution. The phage binding assays and competitive inhibition experiments demonstrated that PA(A)-PG and PA(A)-PL combinations possess comparable binding advantages with hIgG/hIgG1-Fc and hIgM/hIgA respectively.</p> <p>Conclusion</p> <p>In this work, a combinatorial phage library displaying Ig-binding domains of protein A, protein G, or protein L joined by various random linking peptides was used to conducted evolutional selection <it>in vitro</it> with four kinds of Ig molecules. Two kinds of novel combinations of Ig-binding domains, PA(A)-PG and PA(A)-PL, were obtained, and demonstrate the novel Ig binding properties.</p
A Force Sensorless Method for CFRP/Ti Stack Interface Detection during Robotic Orbital Drilling Operations
Drilling carbon fiber reinforced plastics and titanium (CFRP/Ti) stacks is one of the most important activities in aircraft assembly. It is favorable to use different drilling parameters for each layer due to their dissimilar machining properties. However, large aircraft parts with changing profiles lead to variation of thickness along the profiles, which makes it challenging to adapt the cutting parameters for different materials being drilled. This paper proposes a force sensorless method based on cutting force observer for monitoring the thrust force and identifying the drilling material during the drilling process. The cutting force observer, which is the combination of an adaptive disturbance observer and friction force model, is used to estimate the thrust force. An in-process algorithm is developed to monitor the variation of the thrust force for detecting the stack interface between the CFRP and titanium materials. Robotic orbital drilling experiments have been conducted on CFRP/Ti stacks. The estimate error of the cutting force observer was less than 13%, and the stack interface was detected in 0.25 s (or 0.05 mm) before or after the tool transited it. The results show that the proposed method can successfully detect the CFRP/Ti stack interface for the cutting parameters adaptation
Phase transitions in Ising magnetic films and superlattices
Within the framework of mean field theory, we examine the phase transitions
in Ising magnetic films and superlattices. By transfer matrix method, we derive
two general nonlinear equations for phase transition temperatures of Ising
magnetic films and superlattices, respectively. The equations can be applied to
the films and superlattices with arbitrary exchange interaction constants and
arbitrary layer number. Numerical results for phase transition temperatures as
a function of exchange interaction constants are presented.Comment: 10 pages, 3 figures, accepted by Solid State Communication
Cholesteryl ester transfer protein TaqIB polymorphism and its association with serum lipid levels and longevity in Chinese Bama Zhuang population
<p>Abstract</p> <p>Background</p> <p><it>Taq</it>IB polymorphism in the cholesteryl ester transfer protein (CETP) gene has been reported to be associated with serum high-density lipoprotein cholesterol (HDL-C) levels and longevity in several populations, but controversial results also arose probably due to racial/ethnic diversity. Bama is a remote and mountainous county located in the northwest of Guangxi, People's Republic of China, which has been well known for its longevity for centuries. The current study was to investigate the possible association of CETP <it>Taq</it>IB polymorphism with serum lipid levels and longevity in the Bama Zhuang population.</p> <p>Methods</p> <p>The CETP <it>Taq</it>IB genotypes were determined by polymerase chain reaction and restriction fragment length polymorphism in 523 long-lived inhabitants (long-lived group, LG; aged 90-107 years) and 498 healthy controls without longevity family history (non-long-lived group, non-LG; aged 40-69 years) residing in Bama County.</p> <p>Results</p> <p>The levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were higher but TG, HDL-C/LDL-C ratio and the prevalence of dyslipidemia were lower in LG than in non-LG (<it>P </it>< 0.001 for all). There were no differences in the allelic and genotypic frequencies between the two groups (<it>P </it>> 0.05). Serum HDL-C levels and HDL-C/LDL-C ratio in LG were different among the genotypes (<it>P </it>< 0.01 for each), the subjects with B2B2 and B1B2 genotyes had higher HDL-C levels and HDL-C/LDL-C ratio than the subjects with B1B1genotye, whereas the levels of TC and HDL-C in non-LG were different among/between the genotypes (<it>P </it>< 0.01 for each), the B2 allele carriers had lower TC and higher HDL-C levels than the B2 allele noncarriers. Serum TG and HDL-C levels and HDL-C/LDL-C ratio were correlated with genotypes in LG, whereas serum TC and HDL-C levels were associated with genotypes in non-LG (<it>P </it>< 0.05-0.001).</p> <p>Conclusions</p> <p>The association of CETP <it>Taq</it>IB polymorphism and serum lipid profiles is different between LG and non-LG in the Chinese Bama Zhuang population. CETP <it>Taq</it>IB polymorphism might be one of the longevity-related genetic factors in this population.</p
Weighted Gene Correlation Network Analysis (WGCNA) Detected Loss of MAGI2 Promotes Chronic Kidney Disease (CKD) by Podocyte Damage
Background/Aims: Podocyte damage is associated with proteinuria, glomerulosclerosis and decline of renal function. This study aimed to screen critical genes associated with podocyte injury in chronic kidney disease (CKD) by weighted gene correlation network analysis (WGCNA), and explore related functions. Methods: GSE66107, GSE93798, GSE30528, GSE32591 gene expression data including podocyte injury models or glomeruli in CKD patients were downloaded from the GEO database. R was used for data analysis. Differentially expressed genes (DEGs) (FDR< 0.05 or |Fold Change|≥1.5) in GSE993395 were assessed by WGCNA. According to Gene Ontology (GO) and known podocyte standard genes (PSGs), podocyte injury-associated modules were defined, with hub genes selected based on average intramodular connectivity. The Cytoscape software was used for network visualization. Nephroseq was used to assess the clinical significance of hub genes. Small interfering RNA (siRNA) was used to evaluate the roles of hub genes in podocyte injury Results: Totally 7957 DEGs were screened, with 15 (co.DEGs) altered in all 4 datasets; 4031 DEGs were used for WGCNA, encompassing 12 modules. Green modules (most PSGs and co.DEGs) were significantly enriched in glomerular development, and considered podocyte injury-associated modules. Furthermore, MAGI2 (a hub gene) was also a co.DEG and PSG. Glomerular MAGI2 levels were reduced in various kidney diseases, and positively and negatively associated with glomerular filtration rate and urinary protein levels in CKD patients. Moreover, MAIG2 knockdown reduced NPHS2, CD2AP and SYNPO levels, and induced podocyte rearrangement and apoptosis. Conclusion: MAGI2 identified by WGCNA regulates cytoskeletal rearrangement in podocytes, with its loss predisposing to proteinuria and CKD
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