Developmental cues for the maturation of metabolic, electrophysiological and calcium handling properties of human pluripotent stem cell-derived cardiomyocytes

Human pluripotent stem cells (hPSCs), including embryonic and induced pluripotent stem cells, are abundant sources of cardiomyocytes (CMs) for cell replacement therapy and other applications such as disease modeling, drug discovery and cardiotoxicity screening. However, hPSC-derived CMs display immature structural, electrophysiological, calcium-handling and metabolic properties. Here, we review various biological as well as physical and topographical cues that are known to associate with the development of native CMs in vivo to gain insights into the development of strategies for facilitated maturation of hPSC-CMs. © 2014 Keung et al.; licensee BioMed Central Ltd.published_or_final_versio

Effect of sunlight shielding on leaf structure and amino acids concentration of light sensitive albino tea plant

Light sensitive albino tea cultivar ‘Jinguang’ (Camellia sinensis) which grows albinism leaf in yellow colour, results to high level of amino acids but low levels of photosynthetic pigments including chlorophylls, neoxanthin, violaxanthin, phytoxanthin and β-carotene when it is exposed to high sunlight illumination in the summer season. In this case, the chloroplasts showed partially lysed, with few thylakoids. The leaf albinism was reverted when the leaf was shielded from direct illumination of strong sunlight. It is considered that the blocked development of chloroplast and photosynthetic pigments in the albinism leaf inhibited the biosynthesis of leaf proteins, resulting in an accumulation of free amino acids.Keywords: Camellia sinensis, leaf albinism, light intensity, photosynthetic pigments, amino acids, chloroplastAfrican Journal of Biotechnology Vol. 12(36), pp. 5535-553

Fuzzy identity-based data integrity auditing for reliable cloud storage systems

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.As a core security issue in reliable cloud storage, data integrity has received much attention. Data auditing protocols enable a verifier to efficiently check the integrity of the outsourced data without downloading the data. A key research challenge associated with existing designs of data auditing protocols is the complexity in key management. In this paper, we seek to address the complex key management challenge in cloud data integrity checking by introducing fuzzy identity-based auditing-the first in such an approach, to the best of our knowledge. More specifically, we present the primitive of fuzzy identity-based data auditing, where a user’s identity can be viewed as a set of descriptive attributes. We formalize the system model and the security model for this new primitive. We then present a concrete construction of fuzzy identity-based auditing protocol by utilizing biometrics as the fuzzy identity. The new protocol offers the property of error-tolerance, namely, it binds private key to one identity which can be used to verify the correctness of a response generated with another identity, if and only if both identities are sufficiently close. We prove the security of our protocol based on the computational Diffie-Hellman assumption and the discrete logarithm assumption in the selective-ID security model. Finally, we develop a prototype implementation of the protocol which demonstrates the practicality of the proposal.This work is supported by the National Natural Science Foundation of China (61501333,61300213,61272436,61472083), the Fundamental Research Funds for the Central Universities under Grant ZYGX2015J05

Trifun Dimić, Romane, romaja, sovlahimate thaj e bahtarimate = Narodne romske kletve, zakletve i blagoslovi, Srpska čitaonica i knjižnica Irig, Novi Sad 1985. (Edicija "Stražilovo")

This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record.ICT4D 2017: 14th International Conference on Social Implications of Computers in Developing Countries, 22-24 May 2017, Jarkata, IndonesiaInformation systems (IS) failure in developing countries has been often understood as the failure of development practitioners to think and act in accordance with the local context. Such explanatory accounts mostly take contingency as the situation in the local context in which multiple stakeholders can coordinate and adapt to the local conditions, while implementing the globally-applicable logic of dominant institutions. There is a lack of understanding of contingency as the global context of the international development field, in particular how IS failure can be shaped by the state actor. In this paper, we trace the change of the global aid governance that influenced the context of aid information management systems (AIMS) in Indonesia. We argue that understanding the failure of AIMS in Indonesia needs to move from the project’s local situation to the global-level, recursive relationship between the field of aid governance and the state actor. Interpreting AIMS failure as the result of Indonesia’s strategic agency in the shifting landscape of global aid agenda allows information communication and technology (ICTD) researchers to reflect upon the macro political economy of development, in particular how the emerging powers can shape the development agenda in which future ICT innovations unfold

Ab initio calculations of structural and electronic properties of CdTe clusters

We present results of a study of small stoichiometric $Cd_{n}Te_{n}$ ($1{\leq}n{\leq}6$) clusters and few medium sized non-stoichiometric $Cd_{m}Te_{n}$ [($m,n= 13, 16, 19$); ($m{\neq}n$)] clusters using the Density Functional formalism and projector augmented wave method within the generalized gradient approximation. Structural properties {\it viz.} geometry, bond length, symmetry and electronic properties like HOMO-LUMO gap, binding energy, ionization potential and nature of bonding {\it etc.} have been analyzed. Medium sized non-stoichiometric clusters were considered as fragments of the bulk with T{$_{d}$} symmetry. It was observed that upon relaxation, the symmetry changes for the Cd rich clusters whereas the Te rich clusters retain their symmetry. The Cd rich clusters develop a HOMO-LUMO gap due to relaxation whereas there is no change in the HOMO-LUMO gap of the Te rich clusters. Thus, the symmetry of a cluster seems to be an important factor in determining the HOMO-LUMO gap.Comment: 8 pages 16 figure

Covering Problems for Partial Words and for Indeterminate Strings

We consider the problem of computing a shortest solid cover of an indeterminate string. An indeterminate string may contain non-solid symbols, each of which specifies a subset of the alphabet that could be present at the corresponding position. We also consider covering partial words, which are a special case of indeterminate strings where each non-solid symbol is a don't care symbol. We prove that indeterminate string covering problem and partial word covering problem are NP-complete for binary alphabet and show that both problems are fixed-parameter tractable with respect to $k$, the number of non-solid symbols. For the indeterminate string covering problem we obtain a $2^{O(k \log k)} + n k^{O(1)}$-time algorithm. For the partial word covering problem we obtain a $2^{O(\sqrt{k}\log k)} + nk^{O(1)}$-time algorithm. We prove that, unless the Exponential Time Hypothesis is false, no $2^{o(\sqrt{k})} n^{O(1)}$-time solution exists for either problem, which shows that our algorithm for this case is close to optimal. We also present an algorithm for both problems which is feasible in practice.Comment: full version (simplified and corrected); preliminary version appeared at ISAAC 2014; 14 pages, 4 figure

Epigenetic regulation of the electrophysiological phenotype of human embryonic stem cell-derived ventricular cardiomyocytes: Insights for driven maturation and hypertrophic growth

Epigenetic regulation is implicated in embryonic development and the control of gene expression in a cell-specific manner. However, little is known about the role of histone methylation changes on human cardiac differentiation and maturation. Using human embryonic stem cells (hESCs) and their derived ventricular (V) cardiomyocytes (CMs) as a model, we examined trimethylation of histone H3 lysine 4 (H3K4me3) and lysine 27 (H3K27me3) on promoters of genes associated with cardiac electrophysiology, contraction, and Ca2+ handling. To avoid ambiguities due to heterogeneous chamber-specific types, hESC-derived ventricular cardiomyocytes (VCMs) were selected by dual zeocin-GFP expression under the transcriptional control of the MLC2v promoter and confirmed electrophysiologically by its signature action potential phenotype. High levels of H3K4me3 are present on pluripotency genes in hESCs with an absence of H3K27me3. Human ESC-VCMS, relative to hESCs, were characterized by a profound loss of H3K27me3 and an enrichment of H3K4me3 marks on cardiac-specific genes, including MYH6, MYH7, MYL2, cTNT, and ANF. Gene transcripts encoding key voltage-gated ion channels and Ca2+-handling proteins in hESC-VCMs were significantly increased, which could be attributed to a distinct pattern of differential H3K4me3 and H3K27me3 profiles. Treatment of hESC-VCMs with the histone deacetylase inhibitor valproic acid increased H3K4me3 on gene promoters, induced hypertrophic growth (as gauged by cell volume and capacitance), and augmented cardiac gene expression, but it did not affect electrophysiological properties of these cells. Hence, cardiac differentiation of hESCs involves a dynamic shift in histone methylation, which differentially affects VCM gene expression and function. We conclude that the epigenetic state of hESC-VCMs is dynamic and primed to promote growth and developmental maturation, but that proper environmental stimuli with chromatin remodeling will be required to synergistically trigger global CM maturation to a more adult-like phenotype. © Mary Ann Liebert, Inc.published_or_final_versio

Psychological principles of successful aging technologies: A mini-review

Based on resource-oriented conceptions of successful life-span development, we propose three principles for evaluating assistive technology: (a) net resource release; (b) person specificity, and (c) proximal versus distal frames of evaluation. We discuss how these general principles can aid the design and evaluation of assistive technology in adulthood and old age, and propose two technological strategies, one targeting sensorimotor and the other cognitive functioning. The sensorimotor strategy aims at releasing cognitive resources such as attention and working memory by reducing the cognitive demands of sensory or sensorimotor aspects of performance. The cognitive strategy attempts to provide adaptive and individualized cuing structures orienting the individual in time and space by providing prompts that connect properties of the environment to the individual's action goals. We argue that intelligent assistive technology continuously adjusts the balance between `environmental support' and `self-initiated processing' in person-specific and aging-sensitive ways, leading to enhanced allocation of cognitive resources. Furthermore, intelligent assistive technology may foster the generation of formerly latent cognitive resources by activating developmental reserves (plasticity). We conclude that `lifespan technology', if co-constructed by behavioral scientists, engineers, and aging individuals, offers great promise for improving both the transition from middle adulthood to old age and the degree of autonomy in old age in present and future generations. Copyright (C) 2008 S. Karger AG, Basel

GANimation: anatomically-aware facial animation from a single image

The final publication is available at link.springer.comRecent advances in Generative Adversarial Networks (GANs) have shown impressive results for task of facial expression synthesis. The most successful architecture is StarGAN, that conditions GANs' generation process with images of a specific domain, namely a set of images of persons sharing the same expression. While effective, this approach can only generate a discrete number of expressions, determined by the content of the dataset. To address this limitation, in this paper, we introduce a novel GAN conditioning scheme based on Action Units (AU) annotations, which describes in a continuous manifold the anatomical facial movements defining a human expression. Our approach allows controlling the magnitude of activation of each AU and combine several of them. Additionally, we propose a fully unsupervised strategy to train the model, that only requires images annotated with their activated AUs, and exploit attention mechanisms that make our network robust to changing backgrounds and lighting conditions. Extensive evaluation show that our approach goes beyond competing conditional generators both in the capability to synthesize a much wider range of expressions ruled by anatomically feasible muscle movements, as in the capacity of dealing with images in the wild.Peer ReviewedAward-winningPostprint (author's final draft

Allele-specific NKX2-5 binding underlies multiple genetic associations with human electrocardiographic traits.

The cardiac transcription factor (TF) gene NKX2-5 has been associated with electrocardiographic (EKG) traits through genome-wide association studies (GWASs), but the extent to which differential binding of NKX2-5 at common regulatory variants contributes to these traits has not yet been studied. We analyzed transcriptomic and epigenomic data from induced pluripotent stem cell-derived cardiomyocytes from seven related individuals, and identified ~2,000 single-nucleotide variants associated with allele-specific effects (ASE-SNVs) on NKX2-5 binding. NKX2-5 ASE-SNVs were enriched for altered TF motifs, for heart-specific expression quantitative trait loci and for EKG GWAS signals. Using fine-mapping combined with epigenomic data from induced pluripotent stem cell-derived cardiomyocytes, we prioritized candidate causal variants for EKG traits, many of which were NKX2-5 ASE-SNVs. Experimentally characterizing two NKX2-5 ASE-SNVs (rs3807989 and rs590041) showed that they modulate the expression of target genes via differential protein binding in cardiac cells, indicating that they are functional variants underlying EKG GWAS signals. Our results show that differential NKX2-5 binding at numerous regulatory variants across the genome contributes to EKG phenotypes