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Eric Li

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Missouri University of Science and Technology

Robert Aronstam

Shiow-her Chiou

National Chung Hsing University

Hwei-Hsien Chen

Nancy A Monteiro-Riviere

Kansas State University

Tore-geir Iversen

Texas A&M University

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Papers by Eric Li

Cellular internalization of quantum dots noncovalently conjugated with arginine-rich cell-penetrating peptides

… of nanoscience and …, 2010

Protein transduction domains comprised of basic amino acid-rich peptides, can efficiently deliver... more Protein transduction domains comprised of basic amino acid-rich peptides, can efficiently deliver covalently fused macromolecules into cells. Quantum dots (QDs) are luminescent semiconductor nanocrystals that are finding increasing application in biological imaging. Previous studies showed that protein transduction domains mediate the internalization of covalently attached QDs. In this study, we demonstrate that arginine-rich intracellular delivery peptides (cell-penetrating peptides; CPPs), analogs of naturally-occuring protein transduction domains, deliver noncovalently associated QDs into living cells; CPPs dramatically increase the rate and efficiency of cellular uptake of QD probes. The optimal molecular ratio between arginine-rich CPPs and QD cargoes for cellular internalization is approximately 60:1. Upon entry into cells, the QDs are concentrated in the perinuclear region. There is no cytotoxicity following transport of QDs present at concentrations up to 200 nM. The mechanism for arginine-rich CPP/QD complexes to traverse cell membrane appears to involve a combination of internalization pathways. These results provide insight into the mechanism of arginine-rich CPP delivery of noncovalently attached cargoes, and may provide a powerful tool for imaging in vivo.

Recombinant hepatitis C virus in experimentally infected chimpanzees

Genetic recombination between different strains of Hepatitis C virus (HCV) was investigated in th... more Genetic recombination between different strains of Hepatitis C virus (HCV) was investigated in three chimpanzees inoculated experimentally with factor VIII concentrate containing HCV subgenotypes 1a, 1b, 2b and 3a. A 750 bp long fragment from the HCV envelope region was amplified by RT-PCR and quasispecies were isolated by plasmid cloning. Nucleotide sequences derived from isolated quasispecies were screened for the presence of inter-subgenotypic recombination by using sequence analysis. Recombination between HCV subgenotype 1a and 1b was found in two animals; each recombinant variant differed by location of predicted crossover region or order of subgenotype 1a and 1b sequences.

Trp-26 Imparts Functional Versatility to Human α-Defensin HNP1

Journal of Biological …, 2010

We performed a comprehensive alanine scan of human α-defensin HNP1 and tested the ability of the ... more

The Conserved Salt Bridge In Human α-Defensin 5 is Required for Its Precursor Processing and Proteolytic Stability

Journal of Biological …, 2008

Mammalian -defensins, expressed primarily in leukocytes and epithelia, play important roles in in... more

Dynamic projection environments for immersive visualization

We present a system for dynamic projection on large, human-scale, moving projection screens and d... more We present a system for dynamic projection on large, human-scale, moving projection screens and demonstrate this system for immersive visualization applications in several fields. We have designed and implemented efficient, low-cost methods for robust tracking of projection surfaces, and a method to provide high frame rate output for computationally-intensive, low frame rate applications. We present a distributed rendering environment which allows many projectors to work together to illuminate the projection surfaces. This physically immersive visualization environment promotes innovation and creativity in design and analysis applications and facilitates exploration of alternative visualization styles and modes. The system provides for multiple participants to interact in a shared environment in a natural manner. Our new human-scale user interface is intuitive and novice users require essentially no instruction to operate the visualization.

DICER-LIKE2 plays a primary role in transitive silencing of transgenes in Arabidopsis

Dicer-like (DCL) enzymes play a pivotal role in RNA silencing in plants, processing the long doub... more Dicer-like (DCL) enzymes play a pivotal role in RNA silencing in plants, processing the long double-stranded RNA (dsRNA) that triggers silencing into the primary short interfering RNAs (siRNAs) that mediate it. The siRNA population can be augmented and silencing amplified via transitivity, an RNA-dependent RNA polymerase (RDR)-dependent pathway that uses the target RNA as substrate to generate secondary siRNAs. Here we report that Arabidopsis DCL2-but not DCL4-is required for transitivity in cell-autonomous, post-transcriptional silencing of transgenes. An insertion mutation in DCL2 blocked sense transgene-induced silencing and eliminated accumulation of the associated RDR-dependent siRNAs. In hairpin transgeneinduced silencing, the dcl2 mutation likewise eliminated accumulation of secondary siRNAs and blocked transitive silencing, but did not block silencing mediated by primary siRNAs. Strikingly, in all cases, the dcl2 mutation eliminated accumulation of all secondary siRNAs, including those generated by other DCL enzymes. In contrast, mutations in DCL4 promoted a dramatic shift to transitive silencing in the case of the hairpin transgene and enhanced silencing induced by the sense transgene. Suppression of hairpin and sense transgene silencing by the P1/HC-Pro and P38 viral suppressors was associated with elimination of secondary siRNA accumulation, but the suppressors did not block processing of the stem of the hairpin transcript into primary siRNAs. Thus, these viral suppressors resemble the dcl2 mutation in their effects on siRNA biogenesis. We conclude that DCL2 plays an essential, as opposed to redundant, role in transitive silencing of transgenes and may play a more important role in silencing of viruses than currently thought.

HUA1, a regulator of stamen and carpel identities in Arabidopsis, codes for a nuclear RNA binding protein

Stamen and carpel identities are specified by the combinatorial activities of several floral home... more Stamen and carpel identities are specified by the combinatorial activities of several floral homeotic genes, APETALA3 , PISTILLATA , AGAMOUS (AG), SEPALLATA1 (SEP1), SEPALLATA2 (SEP2), and SEPALLATA3 (SEP3), all of which code for MADS domain DNA binding proteins. AG and the SEP genes also control floral determinacy. HUA1 and HUA2 were identified previously as regulators of stamen and carpel identities and floral determinacy because the recessive hua1-1 or hua2-1 allele affected these processes in plants with a lower dosage of functional AG (either homozygous for the weak ag-4 allele or heterozygous for the strong ag-1 allele). HUA2 was cloned previously and shown to code for a novel protein. We isolated the HUA1 gene using a map-based approach and show that it encodes a protein with six CCCHtype zinc finger motifs that is also found in yeast, Caenorhabditis elegans , Drosophila melanogaster , and mammalian proteins. Several such genes from invertebrates and mammals are known to play key regulatory roles in development. Therefore, HUA1 are another example of non-MADS domain proteins involved in organ identity specification. We demonstrated that HUA1 binds ribohomopolymers, preferentially poly rU and poly rG, but not double-stranded DNA in vitro. This finding suggests that HUA1, like several mammalian CCCH zinc finger proteins, is an RNA binding protein. Therefore, HUA1 likely participates in a new regulatory mechanism governing flower development.

Two RNA Binding Proteins, HEN4 and HUA1, Act in the Processing of< i> AGAMOUS</i> Pre-mRNA in< i> Arabidopsis thaliana</i>

Methylation as a crucial step in plant microRNA biogenesis

Materials and Methods Expression and purification of HEN1 protein from Escherichia coli Full-leng... more Materials and Methods Expression and purification of HEN1 protein from Escherichia coli Full-length HEN1 cDNA was generated by a combination of cDNA library screening and 5´RACE (S1). However, a region in the cDNA is apparently a hotspot for an E. coli transposon, and the excision of this transposon causes a one-nucleotide deletion. This was remedied by site-directed mutagenesis to introduce nucleotide substitutions around the deletion site with mHEN1p3 (5´-aagctagggatgaaattgtaggtaggatcaagtatatattttctgatg-3´) and mHEN1p4 (5´-catcagaaaatatatacttgatcctacctacaatttcatccctagctt-3´). The nucleotide substitutions do not affect the amino acid sequence of the protein. This HEN1 cDNA was shown to rescue the hen1-1 mutant phenotype and was used as our wild type, HEN1 cDNA in this report. The full-length HEN1 cDNA was amplified by HEN1p4 (5´ccggaattctcaaagatcagtctttttcttttctacatcttcttt-3´) and HEN1p6 (5´ccggaattcatatggccggtggtgggaagc-3´) and cloned into pGEX-2TK for GST-HEN1 fusion protein expression in E. Coli. pGEX-2TK-HEN1 was mutated by site-directed mutagenesis to change the amino acids in the SAM binding motif. This mutagenesis was performed with primers HEN1Mp1f (5´-catccgcttctactttggttaacgctgtagccgtatctggaagtttattagactctctac-3´) and HEN1Mp2r (5´-gagtctaataaacttccagatacggctacagcgttaaccaaagtagaagcggatgattc-3´). The resulting clone pGEX-2TK-HEN1m2 was sequenced to confirm the presence of the introduced mutations and the absence of any unwanted mutations. GST, GST-HEN1, and GST-HEN1m2 were purified with Glutathione Sepharose 4B affinity columns (Amersham Biosciences) under non-denaturing conditions. Methyltransferase assay The methyltransferase assay was performed in a 100 ml of total reaction mixture, which contained 50 mM Tris/HCl (pH 8.0), 100 mM KCl, 5 mM MgCl 2 , 0.1 mM EDTA, 2 mM DTT, 5% glycerol, 2 ml RNasin (Promega), 0.5 mCi S-adenosyl-L-[methyl-14 C] methionine (58.0mCi/mmole; Amersham Biosciences), and 5 mg purified protein. The reaction was started by the addition of 1 nmol RNA substrate. After 1 hour of incubation at 37°C, the reaction was terminated by adding 100 ml of the stopping solution [100 mM Tris/HCl (pH8.0), 10 mM EDTA, 150 mM NaCl, 2% SDS, and 0.4 mg/ml proteinase K] and followed by incubation at 65°C for 15 min. The reaction was extracted with phenol/chloroform and the RNA was ethanol precipitated and analyzed in a 15% polyacrylamide gel. The gel was treated with an autoradiography enhancer (En 3 hance from PerkinElmer) and exposed to X-ray film at-80°C.

CARPEL FACTORY, a Dicer homolog, and HEN1, a novel protein, act in microRNA metabolism in Arabidopsis thaliana

induced silencing complex (RISC), which targets homologous RNAs for degradation ([6, 7], reviewed... more

What is the Role of Attention in Adapting to Ensembles?

Decade of the Mind VI, 2010

Previously psychophysical and neurophysiological studies have separately investigated the effects... more Previously psychophysical and neurophysiological studies have separately investigated the effects of attention on adaptation and statistical processing. Here, we study the influence of attention on the tilt aftereffect induced from an ensemble of oriented Gabor elements. We found that reduced attention facilitates adaptation at an ensemble level.

Oxygen-Vacancy-Related Dielectric Relaxation and Electric Conduction in KNbO3 Ceramic

Integrated Ferroelectrics, 2010

ABSTRACT The temperature and frequency dependent dielectric and conductivity properties were meas... more ABSTRACT The temperature and frequency dependent dielectric and conductivity properties were measured on as-sintered as well as oxygen annealed KNbO3 ceramics. The results show that in addition to phase transition peaks, well defined relaxation peaks are observed in the temperature range 450–700 K. These peaks could be suppressed by annealing the samples in the oxygen atmosphere. The dc-conductivity and maximum dielectric constant values decreases after oxygen annealing. The results are explained on the basis of defect concentration and their dynamics.

Hydrogen Adsorption of Open-Tipped Insufficiently Graphitized Multiwalled Carbon Nanotubes

Applied Physics …, 2003

Carbon nanotubes (CNTs) as a promising candidate for hydrogen storage were first reported in 1997... more

The Effect of Innate Immunity on Autoimmune Diabetes and the Expression of Toll-Like Receptors on Pancreatic Islets

The Journal of Immunology, 2004

Viral infections have previously been implicated as a trigger of autoimmune diabetes. In this stu... more

Core-Shell Tecto(dendrimers): I. Synthesis and Characterization of Saturated Shell Models

Advanced Materials, 2000

A pilot study

Addictive Behaviors, 2000

On the Potentially Pk-Graphic Sequences

Discrete Math, 1999

A nonincreasing sequence n of n nonnegative integers is said to be graphic if it is the degree se... more

Inducible nuclear factor-kappaB activation contributes to chemotherapy resistance …

Journal of the …

BACKGROUND: Activation of nuclear factor-kappaB (NF-kappaB) inhibits chemotherapy-induced apoptos... more

The MicroRNA159-Regulated GAMYB-Like Genes Inhibit Growth and Promote Programmed Cell Death In Arabidopsis

Plant Physiology, Aug 10, 2010

The microRNA159 (miR159) family represses the conserved GAMYB-like genes that encode R2R3 MYB dom... more The microRNA159 (miR159) family represses the conserved GAMYB-like genes that encode R2R3 MYB domain transcription factors that have been implicated in gibberellin (GA) signaling in anthers and germinating seeds. In Arabidopsis (Arabidopsis thaliana), the two major miR159 family members, miR159a and miR159b, are functionally specific for two GAMYB-like genes, MYB33 and MYB65. These transcription factors have been shown to be involved in anther development, but there are differing reports about their role in the promotion of flowering and little is known about their function in seed germination. To understand the function of this pathway, we identified the genes and processes controlled by these GAMYB-like genes. First, we demonstrate that miR159 completely represses MYB33 and MYB65 in vegetative tissues. We show that GA does not release this repression and that these transcription factors are not required for flowering or growth. By contrast, in the absence of miR159, the deregulati...

Expression of growth differentiation factor 9 (GDF9), ALK5, and claudin-11 in adult alpaca testis

Acta Histochemica, 2013

Growth differentiation factor 9 (GDF9) is an oocyte-derived factor critical for folliculogenesis.... more Growth differentiation factor 9 (GDF9) is an oocyte-derived factor critical for folliculogenesis. Recently, in vitro data showed that GDF9 inhibited the localization of tight junction (TJ) proteins, suggesting that GDF9 could potentially regulate spermatogenesis in vivo, via inhibition of Sertoli cell TJ function. The purpose of the present study was to determine the expression and localization of GDF9, its receptor, ALK5, and its latent target protein, claudin-11 (one of TJ proteins) in adult alpaca testis using Western blot and immunohistochemistry. Western blotting results demonstrated that GDF9, ALK5 and claudin-11 were expressed in the adult alpaca testis. Immunohistochemistry revealed that GDF9 was expressed stage-specifically in the cytoplasm of pachytene spermatocytes and round spermatids of the adult alpaca seminiferous epithelium. Type I receptor, ALK5 was mainly localized in the cytoplasm of round spermatids and Leydig cells, and to a lesser extent in the cytoplasm of pachytene spermatocytes and Sertoli cells. Its latent target protein, claudin-11, was perpendicular or parallel to the basal lamina in the basal part of Sertoli cells. These results indicated that GDF9, as a paracrine and autocrine growth factor derived from round spermatids and pachytene spermatocytes, is involved in regulating spermatogenesis via action on germ cells or somatic cells (i.e. Leydig cells, Sertoli cells).

Cellular internalization of quantum dots noncovalently conjugated with arginine-rich cell-penetrating peptides

… of nanoscience and …, 2010

Protein transduction domains comprised of basic amino acid-rich peptides, can efficiently deliver... more Protein transduction domains comprised of basic amino acid-rich peptides, can efficiently deliver covalently fused macromolecules into cells. Quantum dots (QDs) are luminescent semiconductor nanocrystals that are finding increasing application in biological imaging. Previous studies showed that protein transduction domains mediate the internalization of covalently attached QDs. In this study, we demonstrate that arginine-rich intracellular delivery peptides (cell-penetrating peptides; CPPs), analogs of naturally-occuring protein transduction domains, deliver noncovalently associated QDs into living cells; CPPs dramatically increase the rate and efficiency of cellular uptake of QD probes. The optimal molecular ratio between arginine-rich CPPs and QD cargoes for cellular internalization is approximately 60:1. Upon entry into cells, the QDs are concentrated in the perinuclear region. There is no cytotoxicity following transport of QDs present at concentrations up to 200 nM. The mechanism for arginine-rich CPP/QD complexes to traverse cell membrane appears to involve a combination of internalization pathways. These results provide insight into the mechanism of arginine-rich CPP delivery of noncovalently attached cargoes, and may provide a powerful tool for imaging in vivo.

Recombinant hepatitis C virus in experimentally infected chimpanzees

Genetic recombination between different strains of Hepatitis C virus (HCV) was investigated in th... more Genetic recombination between different strains of Hepatitis C virus (HCV) was investigated in three chimpanzees inoculated experimentally with factor VIII concentrate containing HCV subgenotypes 1a, 1b, 2b and 3a. A 750 bp long fragment from the HCV envelope region was amplified by RT-PCR and quasispecies were isolated by plasmid cloning. Nucleotide sequences derived from isolated quasispecies were screened for the presence of inter-subgenotypic recombination by using sequence analysis. Recombination between HCV subgenotype 1a and 1b was found in two animals; each recombinant variant differed by location of predicted crossover region or order of subgenotype 1a and 1b sequences.

Trp-26 Imparts Functional Versatility to Human α-Defensin HNP1

Journal of Biological …, 2010

We performed a comprehensive alanine scan of human α-defensin HNP1 and tested the ability of the ... more

The Conserved Salt Bridge In Human α-Defensin 5 is Required for Its Precursor Processing and Proteolytic Stability

Journal of Biological …, 2008

Mammalian -defensins, expressed primarily in leukocytes and epithelia, play important roles in in... more

Dynamic projection environments for immersive visualization

We present a system for dynamic projection on large, human-scale, moving projection screens and d... more We present a system for dynamic projection on large, human-scale, moving projection screens and demonstrate this system for immersive visualization applications in several fields. We have designed and implemented efficient, low-cost methods for robust tracking of projection surfaces, and a method to provide high frame rate output for computationally-intensive, low frame rate applications. We present a distributed rendering environment which allows many projectors to work together to illuminate the projection surfaces. This physically immersive visualization environment promotes innovation and creativity in design and analysis applications and facilitates exploration of alternative visualization styles and modes. The system provides for multiple participants to interact in a shared environment in a natural manner. Our new human-scale user interface is intuitive and novice users require essentially no instruction to operate the visualization.

DICER-LIKE2 plays a primary role in transitive silencing of transgenes in Arabidopsis

Dicer-like (DCL) enzymes play a pivotal role in RNA silencing in plants, processing the long doub... more Dicer-like (DCL) enzymes play a pivotal role in RNA silencing in plants, processing the long double-stranded RNA (dsRNA) that triggers silencing into the primary short interfering RNAs (siRNAs) that mediate it. The siRNA population can be augmented and silencing amplified via transitivity, an RNA-dependent RNA polymerase (RDR)-dependent pathway that uses the target RNA as substrate to generate secondary siRNAs. Here we report that Arabidopsis DCL2-but not DCL4-is required for transitivity in cell-autonomous, post-transcriptional silencing of transgenes. An insertion mutation in DCL2 blocked sense transgene-induced silencing and eliminated accumulation of the associated RDR-dependent siRNAs. In hairpin transgeneinduced silencing, the dcl2 mutation likewise eliminated accumulation of secondary siRNAs and blocked transitive silencing, but did not block silencing mediated by primary siRNAs. Strikingly, in all cases, the dcl2 mutation eliminated accumulation of all secondary siRNAs, including those generated by other DCL enzymes. In contrast, mutations in DCL4 promoted a dramatic shift to transitive silencing in the case of the hairpin transgene and enhanced silencing induced by the sense transgene. Suppression of hairpin and sense transgene silencing by the P1/HC-Pro and P38 viral suppressors was associated with elimination of secondary siRNA accumulation, but the suppressors did not block processing of the stem of the hairpin transcript into primary siRNAs. Thus, these viral suppressors resemble the dcl2 mutation in their effects on siRNA biogenesis. We conclude that DCL2 plays an essential, as opposed to redundant, role in transitive silencing of transgenes and may play a more important role in silencing of viruses than currently thought.

HUA1, a regulator of stamen and carpel identities in Arabidopsis, codes for a nuclear RNA binding protein

Stamen and carpel identities are specified by the combinatorial activities of several floral home... more Stamen and carpel identities are specified by the combinatorial activities of several floral homeotic genes, APETALA3 , PISTILLATA , AGAMOUS (AG), SEPALLATA1 (SEP1), SEPALLATA2 (SEP2), and SEPALLATA3 (SEP3), all of which code for MADS domain DNA binding proteins. AG and the SEP genes also control floral determinacy. HUA1 and HUA2 were identified previously as regulators of stamen and carpel identities and floral determinacy because the recessive hua1-1 or hua2-1 allele affected these processes in plants with a lower dosage of functional AG (either homozygous for the weak ag-4 allele or heterozygous for the strong ag-1 allele). HUA2 was cloned previously and shown to code for a novel protein. We isolated the HUA1 gene using a map-based approach and show that it encodes a protein with six CCCHtype zinc finger motifs that is also found in yeast, Caenorhabditis elegans , Drosophila melanogaster , and mammalian proteins. Several such genes from invertebrates and mammals are known to play key regulatory roles in development. Therefore, HUA1 are another example of non-MADS domain proteins involved in organ identity specification. We demonstrated that HUA1 binds ribohomopolymers, preferentially poly rU and poly rG, but not double-stranded DNA in vitro. This finding suggests that HUA1, like several mammalian CCCH zinc finger proteins, is an RNA binding protein. Therefore, HUA1 likely participates in a new regulatory mechanism governing flower development.

Two RNA Binding Proteins, HEN4 and HUA1, Act in the Processing of< i> AGAMOUS</i> Pre-mRNA in< i> Arabidopsis thaliana</i>

Methylation as a crucial step in plant microRNA biogenesis

Materials and Methods Expression and purification of HEN1 protein from Escherichia coli Full-leng... more Materials and Methods Expression and purification of HEN1 protein from Escherichia coli Full-length HEN1 cDNA was generated by a combination of cDNA library screening and 5´RACE (S1). However, a region in the cDNA is apparently a hotspot for an E. coli transposon, and the excision of this transposon causes a one-nucleotide deletion. This was remedied by site-directed mutagenesis to introduce nucleotide substitutions around the deletion site with mHEN1p3 (5´-aagctagggatgaaattgtaggtaggatcaagtatatattttctgatg-3´) and mHEN1p4 (5´-catcagaaaatatatacttgatcctacctacaatttcatccctagctt-3´). The nucleotide substitutions do not affect the amino acid sequence of the protein. This HEN1 cDNA was shown to rescue the hen1-1 mutant phenotype and was used as our wild type, HEN1 cDNA in this report. The full-length HEN1 cDNA was amplified by HEN1p4 (5´ccggaattctcaaagatcagtctttttcttttctacatcttcttt-3´) and HEN1p6 (5´ccggaattcatatggccggtggtgggaagc-3´) and cloned into pGEX-2TK for GST-HEN1 fusion protein expression in E. Coli. pGEX-2TK-HEN1 was mutated by site-directed mutagenesis to change the amino acids in the SAM binding motif. This mutagenesis was performed with primers HEN1Mp1f (5´-catccgcttctactttggttaacgctgtagccgtatctggaagtttattagactctctac-3´) and HEN1Mp2r (5´-gagtctaataaacttccagatacggctacagcgttaaccaaagtagaagcggatgattc-3´). The resulting clone pGEX-2TK-HEN1m2 was sequenced to confirm the presence of the introduced mutations and the absence of any unwanted mutations. GST, GST-HEN1, and GST-HEN1m2 were purified with Glutathione Sepharose 4B affinity columns (Amersham Biosciences) under non-denaturing conditions. Methyltransferase assay The methyltransferase assay was performed in a 100 ml of total reaction mixture, which contained 50 mM Tris/HCl (pH 8.0), 100 mM KCl, 5 mM MgCl 2 , 0.1 mM EDTA, 2 mM DTT, 5% glycerol, 2 ml RNasin (Promega), 0.5 mCi S-adenosyl-L-[methyl-14 C] methionine (58.0mCi/mmole; Amersham Biosciences), and 5 mg purified protein. The reaction was started by the addition of 1 nmol RNA substrate. After 1 hour of incubation at 37°C, the reaction was terminated by adding 100 ml of the stopping solution [100 mM Tris/HCl (pH8.0), 10 mM EDTA, 150 mM NaCl, 2% SDS, and 0.4 mg/ml proteinase K] and followed by incubation at 65°C for 15 min. The reaction was extracted with phenol/chloroform and the RNA was ethanol precipitated and analyzed in a 15% polyacrylamide gel. The gel was treated with an autoradiography enhancer (En 3 hance from PerkinElmer) and exposed to X-ray film at-80°C.

CARPEL FACTORY, a Dicer homolog, and HEN1, a novel protein, act in microRNA metabolism in Arabidopsis thaliana

induced silencing complex (RISC), which targets homologous RNAs for degradation ([6, 7], reviewed... more

What is the Role of Attention in Adapting to Ensembles?

Decade of the Mind VI, 2010

Previously psychophysical and neurophysiological studies have separately investigated the effects... more Previously psychophysical and neurophysiological studies have separately investigated the effects of attention on adaptation and statistical processing. Here, we study the influence of attention on the tilt aftereffect induced from an ensemble of oriented Gabor elements. We found that reduced attention facilitates adaptation at an ensemble level.

Oxygen-Vacancy-Related Dielectric Relaxation and Electric Conduction in KNbO3 Ceramic

Integrated Ferroelectrics, 2010

ABSTRACT The temperature and frequency dependent dielectric and conductivity properties were meas... more ABSTRACT The temperature and frequency dependent dielectric and conductivity properties were measured on as-sintered as well as oxygen annealed KNbO3 ceramics. The results show that in addition to phase transition peaks, well defined relaxation peaks are observed in the temperature range 450–700 K. These peaks could be suppressed by annealing the samples in the oxygen atmosphere. The dc-conductivity and maximum dielectric constant values decreases after oxygen annealing. The results are explained on the basis of defect concentration and their dynamics.

Hydrogen Adsorption of Open-Tipped Insufficiently Graphitized Multiwalled Carbon Nanotubes

Applied Physics …, 2003

Carbon nanotubes (CNTs) as a promising candidate for hydrogen storage were first reported in 1997... more

The Effect of Innate Immunity on Autoimmune Diabetes and the Expression of Toll-Like Receptors on Pancreatic Islets

The Journal of Immunology, 2004

Viral infections have previously been implicated as a trigger of autoimmune diabetes. In this stu... more

Core-Shell Tecto(dendrimers): I. Synthesis and Characterization of Saturated Shell Models

Advanced Materials, 2000

A pilot study

Addictive Behaviors, 2000

On the Potentially Pk-Graphic Sequences

Discrete Math, 1999

A nonincreasing sequence n of n nonnegative integers is said to be graphic if it is the degree se... more

Inducible nuclear factor-kappaB activation contributes to chemotherapy resistance …

Journal of the …

BACKGROUND: Activation of nuclear factor-kappaB (NF-kappaB) inhibits chemotherapy-induced apoptos... more

The MicroRNA159-Regulated GAMYB-Like Genes Inhibit Growth and Promote Programmed Cell Death In Arabidopsis

Plant Physiology, Aug 10, 2010

The microRNA159 (miR159) family represses the conserved GAMYB-like genes that encode R2R3 MYB dom... more The microRNA159 (miR159) family represses the conserved GAMYB-like genes that encode R2R3 MYB domain transcription factors that have been implicated in gibberellin (GA) signaling in anthers and germinating seeds. In Arabidopsis (Arabidopsis thaliana), the two major miR159 family members, miR159a and miR159b, are functionally specific for two GAMYB-like genes, MYB33 and MYB65. These transcription factors have been shown to be involved in anther development, but there are differing reports about their role in the promotion of flowering and little is known about their function in seed germination. To understand the function of this pathway, we identified the genes and processes controlled by these GAMYB-like genes. First, we demonstrate that miR159 completely represses MYB33 and MYB65 in vegetative tissues. We show that GA does not release this repression and that these transcription factors are not required for flowering or growth. By contrast, in the absence of miR159, the deregulati...

Expression of growth differentiation factor 9 (GDF9), ALK5, and claudin-11 in adult alpaca testis

Acta Histochemica, 2013

Growth differentiation factor 9 (GDF9) is an oocyte-derived factor critical for folliculogenesis.... more Growth differentiation factor 9 (GDF9) is an oocyte-derived factor critical for folliculogenesis. Recently, in vitro data showed that GDF9 inhibited the localization of tight junction (TJ) proteins, suggesting that GDF9 could potentially regulate spermatogenesis in vivo, via inhibition of Sertoli cell TJ function. The purpose of the present study was to determine the expression and localization of GDF9, its receptor, ALK5, and its latent target protein, claudin-11 (one of TJ proteins) in adult alpaca testis using Western blot and immunohistochemistry. Western blotting results demonstrated that GDF9, ALK5 and claudin-11 were expressed in the adult alpaca testis. Immunohistochemistry revealed that GDF9 was expressed stage-specifically in the cytoplasm of pachytene spermatocytes and round spermatids of the adult alpaca seminiferous epithelium. Type I receptor, ALK5 was mainly localized in the cytoplasm of round spermatids and Leydig cells, and to a lesser extent in the cytoplasm of pachytene spermatocytes and Sertoli cells. Its latent target protein, claudin-11, was perpendicular or parallel to the basal lamina in the basal part of Sertoli cells. These results indicated that GDF9, as a paracrine and autocrine growth factor derived from round spermatids and pachytene spermatocytes, is involved in regulating spermatogenesis via action on germ cells or somatic cells (i.e. Leydig cells, Sertoli cells).