Copy number variation and selection during reprogramming to pluripotency

The mechanisms underlying the low efficiency of reprogramming somatic cells into induced pluripotent stem (iPS) cells are poorly understood. There is a clear need to study whether the reprogramming process itself compromises genomic integrity and, through this, the efficiency of iPS cell establishment. Using a high-resolution single nucleotide polymorphism array, we compared copy number variations (CNVs) of different passages of human iPS cells with their fibroblast cell origins and with human embryonic stem (ES) cells. Here we show that significantly more CNVs are present in early-passage human iPS cells than intermediate passage human iPS cells, fibroblasts or human ES cells. Most CNVs are formed de novo and generate genetic mosaicism in early-passage human iPS cells. Most of these novel CNVs rendered the affected cells at a selective disadvantage. Remarkably, expansion of human iPS cells in culture selects rapidly against mutated cells, driving the lines towards a genetic state resembling human ES cells.     

Effect of splenectomy on the humoral immune response in the lizard, Scincus scincus.

Adult splenectomy in the lizard, Scincus scincus, did not affect humoral immune response to rat erythrocytes until 30 days post-immunization, but severely depressed subsequent antibody production.     

The existence and stability of nontrivial steady-state for a delay competition-diffusion model

This paper investigates the competition diffusion model with delay. The existence and stability of nontrivial steady state are studied. Foundation item: Supported by the National Natural Science Foundation of China Biography: ZHOU Li (1939-), male, Professor, research interest is in partial differential equation.     

Adaptive Event-Triggering Consensus for Multi-Agent Systems with Linear Time-Varying Dynamics

In this paper, the authors study the fully distributed event-triggering consensus problem for multi-agent systems with linear time-varying dynamics, where each agent is described by a linear time-varying system. An adaptive event-triggering protocol is proposed for time-varying multi-agent systems under directed graph. Based on the Gramian matrix of linear time-varying systems, the design of control gain is done and sufficient conditions ensuring the consensus of linear time-varying multiagent s...     

Optimal Quantization of the Support of a Continuous Multivariate Distribution based on Mutual Information

Based on the notion of mutual information between the components of a random vector, we construct, for data reduction reasons, an optimal quantization of the support of its probability measure. More precisely, we propose a simultaneous discretization of the whole set of the components of the random vector which takes into account, as much as possible, the stochastic dependence between them. Examples are presented.     

Effects of -NO2 and -NH2 functional groups in mixed-linker Zr-based MOFs on gas adsorption of CO2 and CH4

This study was undertaken to evaluate the effects of mixing BDC-NO_2 and BDC-NH_2 linkers in the synthesis of Zrbased metal organic frameworks(Zr-MOFs) on their adsorption and separation of CO_2 and CH_4. Ui O-66 with single or binary-NO_2 and-NH2 samples were synthesized under solvothermal conditions and activated by solvent exchanging using methanol. Structural analyses of the materials were conducted using FTIR, XRD, TGA,SEM,1 HNMR and N2 adsorption/desorption techniques and adsorption of CO_2 and CH_4 at high pressures and different temperatures(273 and 298 K) was investigated. It was found that Ui O-66-NH2 exhibited higher CO_2 and CH_4 adsorption capacities than those of Ui O-66-NO_2. Addition of-NH_2 functional group in Ui O-66-NO_2 could enhance CO_2 and CH_4 adsorption due to the extra CO_2 adsorption sites of-NH_2 functional groups. Addition of-NO_2 functional group to Ui O-66-NH2 at a low loading could also increase CO_2 and CH_4 adsorption, however,a high loading of NO_2 functional group to Ui O-66-NH2 would result in decreased adsorption.     

Effect of splenectomy on the humoral immune response in the lizard,Scincus scincus

Summary Adult splenectomy in the lizard,Scincus scincus, did not affect humoral immune response to rat erythrocytes until 30 days post-immunization, but severely depressed subsequent antibody production.This work was supported by United States Public Health Research, grant No. 03-015-N.     

Loss-of-function mutations in the cathepsin C gene result in periodontal disease and palmoplantar keratosis

Papillon-Lefèvre syndrome, or keratosis palmoplantaris with periodontopathia (PLS, MIM 245000), is an autosomal recessive disorder that is mainly ascertained by dentists because of the severe periodontitis that afflicts patients. Both the deciduous and permanent dentitions are affected, resulting in premature tooth loss. Palmoplantar keratosis, varying from mild psoriasiform scaly skin to overt hyperkeratosis, typically develops within the first three years of life. Keratosis also affects other sites such as elbows and knees. Most PLS patients display both periodontitis and hyperkeratosis. Some patients have only palmoplantar keratosis or periodontitis, and in rare individuals the periodontitis is mild and of late onset. The PLS locus has been mapped to chromosome 11q14-q21 (refs 7, 8, 9). Using homozygosity mapping in eight small consanguineous families, we have narrowed the candidate region to a 1.2-cM interval between D11S4082 and D11S931. The gene (CTSC) encoding the lysosomal protease cathepsin C (or dipeptidyl aminopeptidase I) lies within this interval. We defined the genomic structure of CTSC and found mutations in all eight families. In two of these families we used a functional assay to demonstrate an almost total loss of cathepsin C activity in PLS patients and reduced activity in obligate carriers.