Publications by authors named "Arindam Dasgupta"

The 18 Workshop on Recent Issues in Bioanalysis (18 WRIB) took place in San Antonio, TX, USA on May 6-10, 2024. Over 1100 professionals representing pharma/biotech companies, CROs, and multiple regulatory agencies convened to actively discuss the most current topics of interest in bioanalysis. The 18 WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week to allow an exhaustive and thorough coverage of all major issues in bioanalysis of biomarkers, immunogenicity, gene therapy, cell therapy and vaccines.

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Room-temperature longwave infrared (LWIR) detectors are preferred over cryogenically cooled solutions due to the cost effectiveness and ease of operation. The performance of present uncooled LWIR detectors such as microbolometers, is limited by reduced sensitivity, slow response time, and the lack of dynamic spectral tunability. Here, we present a graphene-based efficient room-temperature LWIR detector with high detectivity and fast response time utilizing its tunable optical and electronic characteristics.

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The 16 Workshop on Recent Issues in Bioanalysis (16 WRIB) took place in Atlanta, GA, USA on September 26-30, 2022. Over 1000 professionals representing pharma/biotech companies, CROs, and multiple regulatory agencies convened to actively discuss the most current topics of interest in bioanalysis. The 16th WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccines.

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The design and formation of van der Waals (vdW) heterostructures with different two-dimensional (2D) materials provide an opportunity to create materials with extraordinary physical properties tailored toward specific applications. Mechanical exfoliation of natural vdW materials has been recognized as an effective way for producing high-quality ultrathin vdW heterostructures. Abramovite is one of such naturally occurring vdW materials, where the superlattice is composed of alternating PbBiS and SnInS 2D material lattices.

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Cannizzarite is a naturally occurring mineral formed by van der Waals (vdW) stacking of alternating layers of PbS-like and BiS-like two-dimensional (2D) materials. Although the PbS-type and BiS-type 2D material layers are structurally isotropic individually, the forced commensuration between these two types of layers while forming the heterostructure of cannizzarite induces strong structural anisotropy. Here we demonstrate the mechanical exfoliation of natural cannizzarite mineral to obtain thin vdW heterostructures of PbS-type and BiS-type atomic layers.

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The 15th edition of the Workshop on Recent Issues in Bioanalysis (15th WRIB) was held on 27 September to 1 October 2021. Even with a last-minute move from in-person to virtual, an overwhelmingly high number of nearly 900 professionals representing pharma and biotech companies, contract research organizations (CROs), and multiple regulatory agencies still eagerly convened to actively discuss the most current topics of interest in bioanalysis. The 15th WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccines.

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With the globalization of clinical trials, regulators have increased collaboration to evaluate the adequacy of clinical trial conduct and to optimize regulatory oversight. The 2020 joint Good Clinical Practice (GCP) symposium of the US Food and Drug Administration and the UK Medicines and Healthcare products Regulatory Agency provided the agencies' perspectives on the challenges in ensuring data quality in novel clinical trial designs and the importance of the management and documentation of protocol deviations, sponsor oversight of clinical trials, and use of electronic source data, including electronic health records. This paper summarizes considerations of both agencies on these topics, along with case examples.

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Article Synopsis
  • The 14th Workshop on Recent Issues in Bioanalysis (14 WRIB) took place virtually from June 15-29, 2020, attracting over 1000 participants from various sectors in the pharmaceutical and biotech industries, as well as regulatory agencies globally.
  • The event featured three main workshops and seven specialized workshops over 11 days, focusing on critical topics such as bioanalysis, biomarkers, immunogenicity, gene therapy, and vaccine development.
  • The associated 2020 White Paper offers recommendations based on discussions from the workshop and is divided into three parts, covering various aspects of bioanalytical practices and regulatory compliance, with some sections published in previous volumes of the journal Bioanalysis.
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The 14 edition of the Workshop on Recent Issues in Bioanalysis (14 WRIB) was held virtually on June 15-29, 2020 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. The 14 WRIB included three Main Workshops, seven Specialized Workshops that together spanned 11 days in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccine. Moreover, a comprehensive vaccine assays track; an enhanced cytometry track and updated Industry/Regulators consensus on BMV of biotherapeutics by Mass Spectrometry (hybrid assays, LCMS and HRMS) were special features in 2020.

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Good Clinical Practice (GCP) is an international ethical and scientific quality standard for designing, conducting, recording, and reporting clinical trials. Regulatory agencies conduct GCP inspections to verify the integrity of data generated in clinical trials and to assure the protection of human research subjects, in addition to ensuring that clinical trials are conducted according to the applicable regulations. The first joint GCP workshop of the US Food and Drug Administration (FDA) Center for Drug Evaluation and Research (CDER) and the United Kingdom Medicines and Healthcare products Regulatory Agency (MHRA-UK) was held in October 2018 and provided the agencies' perspectives on the importance of data quality management practices on data integrity.

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Article Synopsis
  • The 2019 Workshop on Recent Issues in Bioanalysis (WRIB) was held in New Orleans from April 1-5, with over 1000 attendees from various sectors, focused on topics like bioanalysis and gene therapy.
  • The event spanned five days, providing a platform for discussing current challenges in bioanalysis methods such as LCMS and qPCR.
  • The resulting White Paper, divided into three parts, offers key recommendations based on discussions, covering FDA guidance, ICH draft guidelines, and various topics in biomarker and gene therapy analysis.
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Nonlinear holography enables optical beam generation and holographic image reconstruction at new frequencies other than the excitation fundamental frequency, providing pathways toward unprecedented applications in optical information processing and data security. So far, plasmonic metasurfaces with the thickness of tens of nanometers have been mostly adopted for realizing nonlinear holograms with the potential of on-chip integration but suffering from low conversion efficiency and high absorption loss. Here, we report a nonlinear transition metal dichalcogenide (TMD) hologram with high conversion efficiency and atomic thickness made of only single nanopatterned tungsten disulfide (WS) monolayer, for producing optical vortex beams and Airy beams as well as reconstructing complex holographic images at the second harmonic (SH) frequency.

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Wavelength, polarization and orbital angular momentum of light are important degrees of freedom for processing and encoding information in optical communication. Over the years, the generation and conversion of orbital angular momentum in nonlinear optical media has found many novel applications in the context of optical communication and quantum information processing. With that hindsight, here orbital angular momentum conversion of optical vortices through second-harmonic generation from only one atomically thin WS monolayer is demonstrated at room temperature.

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Electrically controlled optical metal antennas are an emerging class of nanodevices enabling a bilateral transduction between electrons and photons. At the heart of the device is a tunnel junction that may either emit light upon injection of electrons or generate an electrical current when excited by a light wave. The current study explores a technological route for producing these functional units based upon the electromigration of metal constrictions.

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Initiated as a cable-replacement solution, short-range wireless power transfer has rapidly become ubiquitous in the development of modern high-data throughput networking in centimeter to meter accessibility range. Wireless technology is now penetrating a higher level of system integration for chip-to-chip and on-chip radiofrequency interconnects. However, standard CMOS integrated millimeter-wave antennas have typical size commensurable with the operating wavelength, and are thus an unrealistic solution for downsizing transmitters and receivers to the micrometer and nanometer scale.

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Organic molecular nanophotonics has emerged as an important avenue to harness molecular aggregation and crystallization on various functional platforms to obtain nano-optical devices. To this end, there is growing interest to combine organic molecular nanostructures with plasmonic surfaces and interfaces. Motivated by this, herein we introduce a unique geometry: vertically-tapered organic nanowires grown on a plasmonic thin film.

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We experimentally show how a single Ag nanoparticle (NP) coupled to an Ag nanowire (NW) can convert propagating surface plasmon polaritons to directional photons. By employing dual-excitation Fourier microscopy with spatially filtered collection-optics, we show single- and dual-directional out-coupling of light from NW-NP junction for plasmons excited through glass-substrate and air-superstrate. Furthermore, we show NW-NP junction can influence the directionality of molecular-fluorescence emission, thus functioning as an optical antenna.

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Single-molecule surface-enhanced Raman scattering (SM-SERS) is one of the vital applications of plasmonic nanoparticles. The SM-SERS sensitivity critically depends on plasmonic hot-spots created at the vicinity of such nanoparticles. In conventional fluid-phase SM-SERS experiments, plasmonic hot-spots are facilitated by chemical aggregation of nanoparticles.

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Human T-cell Lymphotropic Viruses type 1 (HTLV-1) is the etiological agent of Adult T-cell Leukemia/Lymphoma. Although associated with lymphocytosis, HTLV-2 infection is not associated with any malignant hematological disease. Similarly, no infection-related symptom has been detected in HTLV-3-infected individuals studied so far.

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Plasmonic nanodimers facilitate electromagnetic hotspots at their gap junction. By loading these gap junctions with nanomaterials, the plasmonic properties of nanodimer can be varied. In this study, we bridged the gap junction of gold (Au) nanocylinder dimer with palladium (Pd), and numerically evaluated the plasmonic properties of the designed nanostructure.

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Although pathways for assembly of RNA polymerase (Pol) II transcription preinitiation complexes (PICs) have been well established in vitro, relatively little is known about the dynamic behavior of Pol II general transcription factors in vivo. In vitro, a subset of Pol II factors facilitates reinitiation by remaining very stably bound to the promoter. This behavior contrasts markedly with the highly dynamic behavior of RNA Pol I transcription complexes in vivo, which undergo cycles of disassembly/reassembly at the promoter for each round of transcription.

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Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of the aggressive and fatal disease adult T-cell leukemia. Previous studies have demonstrated that the HTLV-1-encoded Tax protein inhibits the function of tumor suppressor p53 through a Tax-induced NF-kappaB pathway. Given these attributes, we were interested in the activity of small-molecule inhibitor 9-aminoacridine (9AA), an anticancer drug that targets two important stress response pathways, NF-kappaB and p53.

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Transcription consists of a series of highly regulated steps: assembly of the preinitiation complex (PIC) at the promoter, initiation, elongation, and termination. PIC assembly is nucleated by TFIID, a complex composed of the TATA-binding protein (TBP) and a series of TBP-associated factors (TAFs). One component, TAF7, is incorporated in the PIC through its interaction with TFIID but is released from TFIID upon transcription initiation.

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Human T-lymphotropic virus type 1 (HTLV-1) is the etiologic agent for adult T-cell leukemia. The HTLV-1-encoded protein Tax transactivates the viral long terminal repeat and plays a critical role in virus replication and transformation. Previous work from our laboratory demonstrated that coactivator-associated arginine methytransferase 1, a protein arginine methytransferase, was important for Tax-mediated transactivation.

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