487 research outputs found

    On the density matrix for the kink ground state of higher spin XXZ chain

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    The exact expression for the density matrix of the kink ground state of higher spin XXZ chain is obtained

    Reflection equation for the N=3 Cremmer-Gervais R-matrix

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    We consider the reflection equation of the N=3 Cremmer-Gervais R-matrix. The reflection equation is shown to be equivalent to 38 equations which do not depend on the parameter of the R-matrix, q. Solving those 38 equations. the solution space is found to be the union of two types of spaces, each of which is parametrized by the algebraic variety P1(C)Γ—P1(C)Γ—P2(C)\mathbb{P}^1(\mathbb{C}) \times \mathbb{P}^1(\mathbb{C}) \times \mathbb{P}^2(\mathbb{C}) and CΓ—P1(C)Γ—P2(C) \mathbb{C} \times \mathbb{P}^1(\mathbb{C}) \times \mathbb{P}^2(\mathbb{C}).Comment: 28 pages, revised versio

    On the problem of calculation of correlation functions in the six-vertex model with domain wall boundary conditions

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    The problem of calculation of correlation functions in the six-vertex model with domain wall boundary conditions is addressed by considering a particular nonlocal correlation function, called row configuration probability. This correlation function can be used as building block for computing various (both local and nonlocal) correlation functions in the model. The row configuration probability is calculated using the quantum inverse scattering method; the final result is given in terms of a multiple integral. The connection with the emptiness formation probability, another nonlocal correlation function which was computed elsewhere using similar methods, is also discussed.Comment: 15 pages, 2 figure

    Case Studies of Energy Information Systems and Related Technology: Operational Practices, Costs, and Benefits

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    Energy Information Systems (EIS), which can monitor and analyze building energy consumption and related data throughout the Internet, have been increasing in use over the last decade. Though EIS developers describe the capabilities, costs, and benefits of EIS, many of these descriptions are idealized and often insufficient for potential users to evaluate cost, benefit and operational usefulness. LBNL has conducted a series of case studies of existing EIS and related technology installations. This study explored the following questions: 1) How is the EIS used in day-to-day operation? 2) What are the costs and benefits of an EIS? 3) Where do the energy savings come from? This paper reviews the process of these technologies from installation through energy management practice. The study is based on interviews with operators and energy managers who use EIS. Analysis of energy data trended by EIS and utility bills was also conducted to measure the benefit. This paper explores common uses and findings to identify energy savings attributable to EIS, and discusses nonenergy benefits as well. This paper also addresses technologies related to EIS that have been demonstrated and evaluated by LBNL

    Influence of SIGLEC9 polymorphisms on COPD phenotypes including exacerbation frequency.

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    BACKGROUND AND OBJECTIVE: The exacerbation-prone phenotype of COPD is particularly important, as exacerbations lead to poor quality of life and disease progression. We previously found that COPD patients who lack Siglec-14, a myeloid cell protein that recognizes bacteria and triggers inflammatory responses, are less prone to exacerbation. We hypothesized that the variations in other SIGLEC genes could also influence COPD exacerbation frequency, and investigated the association between SIGLEC9 polymorphisms and the exacerbation-prone phenotype of COPD. METHODS: We examined whether SIGLEC9 polymorphisms affect the frequency of COPD exacerbation in 135 subjects within our study population, and also analysed the correlation between the genotypes and the severity of airflow obstruction and emphysema in 362 Japanese smokers including 244 COPD patients. The association between these single nucleotide polymorphisms (SNPs) and COPD phenotypes were also assessed in a Caucasian population of ECLIPSE study. The effects of these coding SNPs (cSNPs) on Siglec-9 protein functions were analysed using in vitro assays. RESULTS: The G allele of rs2075803 and rs2075803 G/rs2258983 A(GA) haplotype in SIGLEC9 was associated with higher frequency of exacerbations and the extent of emphysema in COPD. These results did not replicate in the ECLIPSE study. A myeloid cell line expressing the Siglec-9 variant corresponding to GA haplotype produced more TNF-Ξ± than the one expressing the variant corresponding to the other major haplotype. CONCLUSION: The SIGLEC9 rs2075803 G/rs2258983 A haplotype, which corresponds to a Siglec-9 variant that is less effective at suppressing inflammatory response, may be a risk factor for the development of emphysema

    Simultaneous disruption of two DNA polymerases, PolΞ· and PolΞΆ, in Avian DT40 cells unmasks the role of PolΞ· in cellular response to various DNA lesions

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    Replicative DNA polymerases are frequently stalled by DNA lesions. The resulting replication blockage is released by homologous recombination (HR) and translesion DNA synthesis (TLS). TLS employs specialized TLS polymerases to bypass DNA lesions. We provide striking in vivo evidence of the cooperation between DNA polymerase Ξ·, which is mutated in the variant form of the cancer predisposition disorder xeroderma pigmentosum (XP-V), and DNA polymerase ΞΆ by generating POLΞ·βˆ’/βˆ’/POLΞΆβˆ’/βˆ’ cells from the chicken DT40 cell line. POLΞΆβˆ’/βˆ’ cells are hypersensitive to a very wide range of DNA damaging agents, whereas XP-V cells exhibit moderate sensitivity to ultraviolet light (UV) only in the presence of caffeine treatment and exhibit no significant sensitivity to any other damaging agents. It is therefore widely believed that PolΞ· plays a very specific role in cellular tolerance to UV-induced DNA damage. The evidence we present challenges this assumption. The phenotypic analysis of POLΞ·βˆ’/βˆ’/POLΞΆβˆ’/βˆ’ cells shows that, unexpectedly, the loss of PolΞ· significantly rescued all mutant phenotypes of POLΞΆβˆ’/βˆ’ cells and results in the restoration of the DNA damage tolerance by a backup pathway including HR. Taken together, PolΞ· contributes to a much wide range of TLS events than had been predicted by the phenotype of XP-V cells

    Anaplastic lymphoma kinase (ALK) inhibitor response in neuroblastoma is highly correlated with ALK mutation status, ALK mRNA and protein levels

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    Background In pediatric neuroblastoma (NBL), high anaplastic lymphoma kinase (ALK) levels appear to be correlated with an unfavorable prognosis, regardless of ALK mutation status. This suggests a therapeutic role for ALK inhibitors in NBL patients. We examined the correlation between levels of ALK, phosphorylated ALK (pALK) and downstream signaling proteins and response to ALK inhibition in a large panel of both ALK mutated and wild type (WT) NBL cell lines. Methods We measured protein levels by western blot and ALK inhibitor sensitivity (TAE684) by viability assays in 19 NBL cell lines of which 6 had a point mutation and 4 an amplification of the ALK gene. Results ALK 220 kDa (p=0.01) and ALK 140 kDa (p= 0.03) protein levels were higher in ALK mutant than WT cell lines. Response to ALK inhibition was significantly correlated with ALK protein levels (p<0.01). ALK mutant cell lines (n=4) were 14,9 fold (p<0,01) more sensitive to ALK inhibition than eight WT cell lines. Conclusion NBL cell lines often express ALK at high levels and are responsive to ALK inhibitors. Mutated cell lines express ALK at higher levels, which may define their superior response to ALK inhibition

    Spt2p Defines a New Transcription-Dependent Gross Chromosomal Rearrangement Pathway

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    Large numbers of gross chromosomal rearrangements (GCRs) are frequently observed in many cancers. High mobility group 1 (HMG1) protein is a non-histone DNA-binding protein and is highly expressed in different types of tumors. The high expression of HMG1 could alter DNA structure resulting in GCRs. Spt2p is a non-histone DNA binding protein in Saccharomyces cerevisiae and shares homology with mammalian HMG1 protein. We found that Spt2p overexpression enhances GCRs dependent on proteins for transcription elongation and polyadenylation. Excess Spt2p increases the number of cells in S phase and the amount of single-stranded DNA (ssDNA) that might be susceptible to cause DNA damage and GCR. Consistently, RNase H expression, which reduces levels of ssDNA, decreased GCRs in cells expressing high level of Spt2p. Lastly, high transcription in the chromosome V, the location at which GCR is monitored, also enhanced GCR formation. We propose a new pathway for GCR where DNA intermediates formed during transcription can lead to genomic instability
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