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  1. Article ; Online: Electrically Tunable Localized versus Delocalized Intralayer Moiré Excitons and Trions in a Twisted MoS

    Dandu, Medha / Gupta, Garima / Dasika, Pushkar / Watanabe, Kenji / Taniguchi, Takashi / Majumdar, Kausik

    ACS nano

    2022  Volume 16, Issue 6, Page(s) 8983–8992

    Abstract: Moiré superlattice (mSL)-induced sub-bands in twisted van der Waals homo- and heterostructures govern their optical and electrical properties, rendering additional degrees of freedom such as twist angle. Here, we demonstrate the moiré superlattice ... ...

    Abstract Moiré superlattice (mSL)-induced sub-bands in twisted van der Waals homo- and heterostructures govern their optical and electrical properties, rendering additional degrees of freedom such as twist angle. Here, we demonstrate the moiré superlattice effects on the intralayer excitons and trions in a twisted bilayer of MoS
    Language English
    Publishing date 2022-06-09
    Publishing country United States
    Document type Journal Article
    ISSN 1936-086X
    ISSN (online) 1936-086X
    DOI 10.1021/acsnano.2c00145
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Book ; Online: Electrically Tunable Localized versus Delocalized Intralayer Moir\'e Excitons and Trions in a Twisted MoS$_2$ Bilayer

    Dandu, Medha / Gupta, Garima / Dasika, Pushkar / Watanabe, Kenji / Taniguchi, Takashi / Majumdar, Kausik

    2022  

    Abstract: Moir\'e superlattice-induced sub-bands in twisted van der Waals homo- and hetero-structures govern their optical and electrical properties, rendering additional degrees of freedom such as twist angle. Here, we demonstrate the moir\'e superlattice effects ...

    Abstract Moir\'e superlattice-induced sub-bands in twisted van der Waals homo- and hetero-structures govern their optical and electrical properties, rendering additional degrees of freedom such as twist angle. Here, we demonstrate the moir\'e superlattice effects on the intralayer excitons and trions in a twisted bilayer of MoS$_2$ of H-type stacking at marginal twist angles. We identify the emission from localized and multiple delocalized sub-bands of intralayer moir\'e excitons and show their electrical modulation by the corresponding trion formation. The electrical control of the oscillator strength of the moir\'e excitons also results in a strong tunability of resonant Raman scattering. We find that the gate-induced doping significantly modulates the electronic moir\'e potential, however leaves the excitonic moir\'e confinement unaltered. This effect, coupled with variable moir\'e trap filling by tuning the optical excitation density, allows us to delineate the different phases of localized and delocalized moir\'e trions. We demonstrate that the moir\'e excitons exhibit strong valley coherence that changes in a striking non-monotonic W-shape with gating due to motional narrowing. These observations from the simultaneous electrostatic control of quasiparticle-dependent moir\'e potential will lead to exciting effects of tunable many-body phenomena in moir\'e superlattices.
    Keywords Condensed Matter - Mesoscale and Nanoscale Physics ; Condensed Matter - Materials Science ; Physics - Applied Physics ; Physics - Optics
    Subject code 535
    Publishing date 2022-03-11
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article: Homologous and heterologous interference requires bovine herpesvirus-1 glycoprotein D at the cell surface during virus entry.

    Dasika, G K / Letchworth, G J

    The Journal of general virology

    2000  Volume 81, Issue Pt 4, Page(s) 1041–1049

    Abstract: Expression of glycoprotein D (gD) of alphaherpesviruses protects cells from superinfection by homologous and heterologous viruses by a mechanism termed interference. We recently showed that MDBK cells expressing bovine herpesvirus (BHV)-1gD (MDBK(gD)) ... ...

    Abstract Expression of glycoprotein D (gD) of alphaherpesviruses protects cells from superinfection by homologous and heterologous viruses by a mechanism termed interference. We recently showed that MDBK cells expressing bovine herpesvirus (BHV)-1gD (MDBK(gD)) resist BHV-1, pseudorabies virus (PRV) and herpes simplex virus-1 (HSV-1) but not the more closely related BHV-5 infection as determined by the number of plaques produced. However, the plaque size is reduced in all four viral infections suggesting a block in cell-to-cell transmission. Here, we show that MDBK cells expressing truncated BHV-1 gD, designated MDBK(t-gD), secreted soluble gD and were fully susceptible to infection by all the four viruses when the cells were washed prior to infection. When MDBK cells or MDBK(t-gD) cells were treated with medium containing truncated gD prior to infection, they partially resisted BHV-1, PRV and HSV-1 but not BHV-5. Interestingly, both BHV-1 and BHV-5 formed normal-sized plaques in MDBK(t-gD) cells suggesting that the viruses were able to spread efficiently. Thus BHV-1 gD is required at the cell surface at the time of infection in order to block BHV-1, HSV-1 and PRV infections, consistent with a common coreceptor for the three gDs.
    MeSH term(s) Amino Acid Sequence ; Animals ; Cattle ; Cell Line ; Genetic Vectors ; Herpesviridae Infections/virology ; Herpesvirus 1, Bovine/physiology ; Molecular Sequence Data ; Transfection ; Viral Proteins/physiology ; Virus Replication
    Chemical Substances Viral Proteins ; bovine herpesvirus type-1 glycoproteins
    Language English
    Publishing date 2000-04
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 219316-4
    ISSN 1465-2099 ; 0022-1317
    ISSN (online) 1465-2099
    ISSN 0022-1317
    DOI 10.1099/0022-1317-81-4-1041
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Cellular expression of bovine herpesvirus 1 gD inhibits cell-to-cell spread of two closely related viruses without blocking their primary infection.

    Dasika, G K / Letchworth, G J

    Virology

    1999  Volume 254, Issue 1, Page(s) 24–36

    Abstract: Alphaherpesviral glycoprotein D (gD) is a critical component of the cell membrane penetration system. Cells that express gD of herpes simplex virus type 1 (HSV1), pseudorabies virus (PRV), or bovine herpesvirus type 1.1 (BHV1.1) resist infection by the ... ...

    Abstract Alphaherpesviral glycoprotein D (gD) is a critical component of the cell membrane penetration system. Cells that express gD of herpes simplex virus type 1 (HSV1), pseudorabies virus (PRV), or bovine herpesvirus type 1.1 (BHV1.1) resist infection by the homologous virus due to interference with viral entry at the level of penetration. BHV1.1 gD interferes with the distantly related viruses HSV1 and PRV despite only a 30-40% sequence similarity and the complete absence of antigenic cross-reactivity among the three gDs. The six cysteines that form three intrachain disulfide bonds in HSV1 are also present in PRV and BHV1.1 gD, suggesting structural similarities among the gD homologs. Functional similarities were postulated to be responsible for cross-interference. To test this hypothesis, we constructed a BHV1.1 gD-expressing cell line (MDBKgD) and assessed its resistance to the homologous BHV1.1 and two closely related viruses, BHV1.2 and BHV5. The gDs of these viruses share 98. 3% and 86% amino acid identity with BHV1.1 gD and bound monoclonal antibodies directed against all five neutralizing epitopes mapped on BHV1.1 gD. MDBKgD cells were resistant to BHV1.1 but fully susceptible to BHV1.2 and BHV5 infection as measured by plaque numbers and single cycle growth kinetics. However, all three viruses, but not vesicular stomatitis virus, made smaller plaques on MDBKgD cells than on control cells. These data suggest that gD-mediated interference is expressed both at the level of initial infection and at the level of cell-to-cell spread and that these two levels can be distinguished by using closely related viruses.
    MeSH term(s) Amino Acid Sequence ; Animals ; Antigens, Viral/immunology ; Cattle ; Cell Line ; Gene Expression ; Herpesvirus 1, Bovine/physiology ; Herpesvirus 1, Human/physiology ; Humans ; Kinetics ; Molecular Sequence Data ; Sequence Homology, Amino Acid ; Viral Interference ; Viral Plaque Assay ; Viral Proteins/biosynthesis ; Viral Proteins/genetics
    Chemical Substances Antigens, Viral ; Viral Proteins ; bovine herpesvirus type-1 glycoproteins
    Language English
    Publishing date 1999-02-01
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 200425-2
    ISSN 1096-0341 ; 0042-6822
    ISSN (online) 1096-0341
    ISSN 0042-6822
    DOI 10.1006/viro.1998.9553
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Relationship between behavioral and physiological spectral-ripple discrimination.

    Won, Jong Ho / Clinard, Christopher G / Kwon, Seeyoun / Dasika, Vasant K / Nie, Kaibao / Drennan, Ward R / Tremblay, Kelly L / Rubinstein, Jay T

    Journal of the Association for Research in Otolaryngology : JARO

    2011  Volume 12, Issue 3, Page(s) 375–393

    Abstract: Previous studies have found a significant correlation between spectral-ripple discrimination and speech and music perception in cochlear implant (CI) users. This relationship could be of use to clinicians and scientists who are interested in using ... ...

    Abstract Previous studies have found a significant correlation between spectral-ripple discrimination and speech and music perception in cochlear implant (CI) users. This relationship could be of use to clinicians and scientists who are interested in using spectral-ripple stimuli in the assessment and habilitation of CI users. However, previous psychoacoustic tasks used to assess spectral discrimination are not suitable for all populations, and it would be beneficial to develop methods that could be used to test all age ranges, including pediatric implant users. Additionally, it is important to understand how ripple stimuli are processed in the central auditory system and how their neural representation contributes to behavioral performance. For this reason, we developed a single-interval, yes/no paradigm that could potentially be used both behaviorally and electrophysiologically to estimate spectral-ripple threshold. In experiment 1, behavioral thresholds obtained using the single-interval method were compared to thresholds obtained using a previously established three-alternative forced-choice method. A significant correlation was found (r = 0.84, p = 0.0002) in 14 adult CI users. The spectral-ripple threshold obtained using the new method also correlated with speech perception in quiet and noise. In experiment 2, the effect of the number of vocoder-processing channels on the behavioral and physiological threshold in normal-hearing listeners was determined. Behavioral thresholds, using the new single-interval method, as well as cortical P1-N1-P2 responses changed as a function of the number of channels. Better behavioral and physiological performance (i.e., better discrimination ability at higher ripple densities) was observed as more channels added. In experiment 3, the relationship between behavioral and physiological data was examined. Amplitudes of the P1-N1-P2 "change" responses were significantly correlated with d' values from the single-interval behavioral procedure. Results suggest that the single-interval procedure with spectral-ripple phase inversion in ongoing stimuli is a valid approach for measuring behavioral or physiological spectral resolution.
    MeSH term(s) Adult ; Aged ; Auditory Cortex/physiology ; Auditory Threshold ; Cochlear Implants ; Deafness/physiopathology ; Discrimination, Psychological ; Female ; Humans ; Male ; Middle Aged ; Psychoacoustics ; Psychometrics ; Speech Perception
    Language English
    Publishing date 2011-01-27
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2021417-0
    ISSN 1438-7573 ; 1525-3961
    ISSN (online) 1438-7573
    ISSN 1525-3961
    DOI 10.1007/s10162-011-0257-4
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Homologous and heterologous interference requires bovine herpesvirus-1 glycoprotein D at the cell surface during virus entry

    Dasika, G.K / Letchworth, G.J

    Journal of general virology. Apr 2000. v. 81 (pt.4)

    2000  

    Abstract: Expression of glycoprotein D (gD) of alphaherpesviruses protects cells from superinfection by homologous and heterologous viruses by a mechanism termed interference. We recently showed that MDBK cells expressing bovine herpesvirus (BHV)-1gD (MDBK(gD)) ... ...

    Abstract Expression of glycoprotein D (gD) of alphaherpesviruses protects cells from superinfection by homologous and heterologous viruses by a mechanism termed interference. We recently showed that MDBK cells expressing bovine herpesvirus (BHV)-1gD (MDBK(gD)) resist BHV-1, pseudorabies virus (PRV) and herpes simplex virus-1 (HSV-1) but not the more closely related BHV-5 infection as determined by the number of plaques produced. However, the plaque size is reduced in all four viral infections suggesting a block in cell-to-cell transmission. Here, we show that MDBK cells expressing truncated BHV-1 gD, designated MDBK(t-gD), secreted soluble gD and were fully susceptible to infection by all the four viruses when the cells were washed prior to infection. When MDBK cells or MDBK(t-gD) cells were treated with medium containing truncated gD prior to infection, they partially resisted BHV-1, PRV and HSV-1 but not BHV-5. Interestingly, both BHV-1 and BHV-5 formed normal-sized plaques in MDBK(t-gD) cells suggesting that the viruses were able to spread efficiently. Thus BHV-1 gD is required at the cell surface at the time of infection in order to block BHV-1, HSV-1 and PRV infections, consistent with a common coreceptor for the three gDs.
    Keywords viral diseases of animals and humans ; animal health ; animal diseases
    Language English
    Dates of publication 2000-04
    Size p. 1041-1049.
    Document type Article
    ZDB-ID 219316-4
    ISSN 1465-2099 ; 0022-1317
    ISSN (online) 1465-2099
    ISSN 0022-1317
    Database NAL-Catalogue (AGRICOLA)

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  7. Article: Cellular expression of bovine herpesvirus 1 gD inhibits cell-to-cell spread of two closely related viruses without blocking their primary infection

    Dasika, G.K / Letchworth, G.J. III

    Virology. Feb 1, 1999. v. 254 (1)

    1999  

    Keywords viral diseases of animals and humans ; animal health ; animal diseases
    Language English
    Dates of publication 1999-0201
    Size p. 24-36.
    Document type Article
    ZDB-ID 200425-2
    ISSN 1096-0341 ; 0042-6822
    ISSN (online) 1096-0341
    ISSN 0042-6822
    Database NAL-Catalogue (AGRICOLA)

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  8. Book ; Online: Automatic Pattern Classification by Unsupervised Learning Using Dimensionality Reduction of Data with Mirroring Neural Networks

    Deepthi, Dasika Ratna / Krishna, G. R. Aditya / Eswaran, K.

    2007  

    Abstract: This paper proposes an unsupervised learning technique by using Multi-layer Mirroring Neural Network and Forgy's clustering algorithm. Multi-layer Mirroring Neural Network is a neural network that can be trained with generalized data inputs (different ... ...

    Abstract This paper proposes an unsupervised learning technique by using Multi-layer Mirroring Neural Network and Forgy's clustering algorithm. Multi-layer Mirroring Neural Network is a neural network that can be trained with generalized data inputs (different categories of image patterns) to perform non-linear dimensionality reduction and the resultant low-dimensional code is used for unsupervised pattern classification using Forgy's algorithm. By adapting the non-linear activation function (modified sigmoidal function) and initializing the weights and bias terms to small random values, mirroring of the input pattern is initiated. In training, the weights and bias terms are changed in such a way that the input presented is reproduced at the output by back propagating the error. The mirroring neural network is capable of reducing the input vector to a great degree (approximately 1/30th the original size) and also able to reconstruct the input pattern at the output layer from this reduced code units. The feature set (output of central hidden layer) extracted from this network is fed to Forgy's algorithm, which classify input data patterns into distinguishable classes. In the implementation of Forgy's algorithm, initial seed points are selected in such a way that they are distant enough to be perfectly grouped into different categories. Thus a new method of unsupervised learning is formulated and demonstrated in this paper. This method gave impressive results when applied to classification of different image patterns.

    Comment: Presented in IEEE International Conference on Advances in Computer Vision and Information Technology (ACVIT-07), Nov. 28-30 2007
    Keywords Computer Science - Machine Learning ; Computer Science - Artificial Intelligence ; Computer Science - Neural and Evolutionary Computing
    Subject code 006
    Publishing date 2007-12-06
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article: Cloning and functional studies of a novel gene aberrantly expressed in RB-deficient embryos.

    Yuan, S S / Cox, L A / Dasika, G K / Lee, E Y

    Developmental biology

    1997  Volume 207, Issue 1, Page(s) 62–75

    Abstract: The tumor suppressor RB regulates diverse cellular processes such as G1/S transition, cell differentiation, and cell survival. Indeed, Rb-knockout mice exhibit phenotypes including ectopic mitosis, defective differentiation, and extensive apoptosis in ... ...

    Abstract The tumor suppressor RB regulates diverse cellular processes such as G1/S transition, cell differentiation, and cell survival. Indeed, Rb-knockout mice exhibit phenotypes including ectopic mitosis, defective differentiation, and extensive apoptosis in the neurons. Using differential display, a novel gene, Rig-1, was isolated based on its elevated expression in the hindbrain and spinal cord of Rb-knockout embryos. The longest open reading frame of Rig-1 encoded a polypeptide that consists of a putative extracellular segment with five immunoglobulin-like domains and three fibronectin III-like domains, a putative transmembrane domain, and a distinct intracellular segment. The Rig-1 sequence was 40% identical to the recently identified roundabout protein. Consistent with the predicted transmembrane nature of the protein, Rig-1 protein was present in the membranous fraction. Antisera raised against the putative extracellular and intracellular segments of Rig-1 reacted with an approximately 210-kDa protein in mouse embryonic CNS. Rig-1 mRNA was transiently expressed in the embryonic hindbrain and spinal cord. Elevated levels of Rig-1 mRNA and protein were found in Rb-/- embryos. Ectopic expression of a transmembrane form of Rig-1, but not the secreted form, promoted neuronal cell entrance to S phase and repressed the expression of a marker of differentiated neuron, Talpha1 tubulin. Thus Rig-1, a possible distant relative of roundabout, may mediate some of the pleiotropic roles of RB in the developing neurons.
    MeSH term(s) Alternative Splicing/genetics ; Amino Acid Sequence ; Animals ; Cell Cycle/genetics ; Central Nervous System/embryology ; Central Nervous System/growth & development ; Cloning, Molecular ; Embryonic and Fetal Development ; Fluorescent Antibody Technique ; Gene Expression Regulation, Developmental/genetics ; Immunoglobulins/genetics ; In Situ Hybridization ; Membrane Proteins/chemistry ; Membrane Proteins/genetics ; Mice ; Mice, Knockout ; Molecular Sequence Data ; Nerve Tissue Proteins/chemistry ; Nerve Tissue Proteins/genetics ; RNA, Messenger/genetics ; Receptors, Cell Surface ; Receptors, Immunologic/genetics ; Retinoblastoma Protein/genetics ; Sequence Analysis, DNA ; Sequence Homology, Amino Acid ; Roundabout Proteins
    Chemical Substances Immunoglobulins ; Membrane Proteins ; Nerve Tissue Proteins ; RNA, Messenger ; Receptors, Cell Surface ; Receptors, Immunologic ; Retinoblastoma Protein ; Robo3 protein, mouse
    Language English
    Publishing date 1997-04-01
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 1114-9
    ISSN 1095-564X ; 0012-1606
    ISSN (online) 1095-564X
    ISSN 0012-1606
    DOI 10.1006/dbio.1998.9141
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Bovine herpesvirus type 2 is closely related to the primate alphaherpesviruses.

    Ehlers, B / Goltz, M / Ejercito, M P / Dasika, G K / Letchworth, G J

    Virus genes

    1999  Volume 19, Issue 3, Page(s) 197–203

    Abstract: ... polymerase (U(L)30), a large gene adjacent to the previously identified conserved cluster, and glycoprotein G ...

    Abstract Bovine herpesvirus type 2 (BoHV-2), also known as bovine mammillitis virus, is classified in the Family Herpesviridae, Subfamily Alphaherpesvirinae, and Genus Simplexvirus along with herpes simplex viruses type 1 and 2 (HSV-1 and HSV-2) and other primate simplexviruses on the basis of similarities in 4 genes within the 15 kb U(L) 23-29 cluster. This could be explained either by a global similarity or a recombination event that brought primate herpesviral sequences into a bovine virus. Our sequences for DNA polymerase (U(L)30), a large gene adjacent to the previously identified conserved cluster, and glycoprotein G (U(S)4), a gene as distant from the cluster as possible on the circularized genome, confirm the close relationship between BoHV-2 and the primate simplexviruses, and argue for a global similarity and probably a close evolutionary relationship. Thus one can speculate that BoHV-2 may represent a greater hazard to humans than has been appreciated previously.
    MeSH term(s) Alphaherpesvirinae/classification ; Alphaherpesvirinae/enzymology ; Alphaherpesvirinae/genetics ; Amino Acid Sequence ; Animals ; Cattle ; Cell Line ; DNA, Viral/analysis ; DNA-Directed DNA Polymerase/genetics ; Herpesvirus 2, Bovine/classification ; Herpesvirus 2, Bovine/enzymology ; Herpesvirus 2, Bovine/genetics ; Molecular Sequence Data ; Phylogeny ; Polymerase Chain Reaction ; Primates/virology ; Sequence Homology, Amino Acid
    Chemical Substances DNA, Viral ; DNA-Directed DNA Polymerase (EC 2.7.7.7)
    Language English
    Publishing date 1999
    Publishing country United States
    Document type Journal Article
    ZDB-ID 639496-6
    ISSN 1572-994X ; 0920-8569
    ISSN (online) 1572-994X
    ISSN 0920-8569
    DOI 10.1023/a:1008184630066
    Database MEDical Literature Analysis and Retrieval System OnLINE

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