Reasoning about Actions over Visual and Linguistic Modalities: A Survey

'Actions' play a vital role in how humans interact with the world and enable them to achieve desired goals. As a result, most common sense (CS) knowledge for humans revolves around actions. While 'Reasoning about Actions & Change' (RAC) has been widely studied in the Knowledge Representation community, it has recently piqued the interest of NLP and computer vision researchers. This paper surveys existing tasks, benchmark datasets, various techniques and models, and their respective performance concerning advancements in RAC in the vision and language domain. Towards the end, we summarize our key takeaways, discuss the present challenges facing this research area, and outline potential directions for future research.Comment: 7 pages, 3 figures; This survey will be periodically updated with the latest works in this are

An amino-acid-based self-healing hydrogel: modulation of the self-healing properties by incorporating carbon-based nanomaterials

An amino-acid-based (11-(4-(pyrene-1-yl)butanamido)undecanoic acid) self-repairing hydrogel is reported. The native hydrogel, as well as hybrid hydrogels, have been thoroughly characterized by using various microscopic techniques, including transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy, fluorescence spectroscopy, FTIR spectroscopy, X-ray diffraction, and by using rheological experiments. The native hydrogel exhibited interesting fluorescence properties, as well as a self-healing property. Interestingly, the self-healing, thixotropy, and stiffness of the native hydrogel can be successfully modulated by incorporating carbon-based nanomaterials, including graphene, pristine single-walled carbon nanotubes (Pr-SWCNTs), and both graphene and Pr-SWCNTs, within the native gel system. The self-recovery time of the gel was shortened by the inclusion of reduced graphene oxide (RGO), Pr-SWCNTs, or both RGO and Pr-SWCNTs. Moreover, hybrid gels that contained RGO and/or Pr-SWCNTs exhibited interesting semiconducting behavior

Tuning of silver cluster emission from blue to red using a bio-active peptide in water

Blue, green, and red emitting silver quantum clusters have been prepared through green chemical approach by using a bio-active peptide glutathione (reduced) in a 50 mM phosphate buffer at pH 7.46. This study describes fluorescence emission tuning of the silver clusters by making different sized Ag clusters using slightly different reaction conditions keeping the same stabilizing ligand, reducing agent, solvent system, and silver salt precursor. The preparation procedure of these silver quantum clusters is new and highly reproducible. Each of these clusters shows very interesting fluorescence properties with large stokes shifts, and the quantum yields of blue, green, and red clusters are 2.08%, 0.125%, and 1.39%, respectively. These silver quantum clusters have been characterized by using different techniques including fluorescence spectroscopy, UV-vis spectroscopy, field-emission gun transmission electron microscopic (FEG-TEM) imaging and MALDI-TOF MS analyses. MALDI-TOF MS analyses show that the size of these blue, green and red emitting silver clusters are Ag<SUB>5</SUB> (NC1, nanoclusters 1), Ag<SUB>8</SUB> (NC2, nanoclusters 2) and Ag<SUB>13</SUB> (NC3, nanoclusters 3), respectively, by using 2,5-dihydroxybenzoic acid as a matrix. These clusters are stable in broad ranges of pH. The NC3 (red emitting) has been successfully utilized for selective and sensitive detection of toxic Hg(II) ions in water by using even naked eyes, fluorometric, and calorimetric studies. The lower limit of detection of Hg<SUP>II</SUP> ions in water has been estimated to be 126 and 245 nM from fluorometric and UV-vis analyses, respectively. Enthalpy change (ΔH) during this Hg<SUP>II</SUP> sensing process is 2508 KJ mol<SUP>-1</SUP>

A dynamical motif comprising the interactions between antigens and CD8 T cells may underlie the outcomes of viral infections

Some viral infections culminate in very different outcomes in different individuals. They can be rapidly cleared in some, cause persistent infection in others, and cause mortality from immunopathology in yet others. The conventional view is that the different outcomes arise as a consequence of the complex interactions between a large number of different factors (virus, different immune cells, and cytokines). Here, we identify a simple dynamical motif comprising the essential interactions between antigens and CD8 T cells and posit it as predominantly determining the outcomes. Viral antigen can activate CD8 T cells, which in turn, can kill infected cells. Sustained antigen stimulation, however, can cause CD8 T-cell exhaustion, compromising effector function. Using mathematical modeling, we show that the motif comprising these interactions recapitulates all of the outcomes observed. The motif presents a conceptual framework to understand the variable outcomes of infection. It also explains a number of confounding experimental observations, including the variation in outcomes with the viral inoculum size, the evolutionary advantage of exhaustion in preventing lethal pathology, the ability of natural killer (NK) cells to act as rheostats tuning outcomes, and the role of the innate immune response in the spontaneous clearance of hepatitis C. Interventions that modulate the interactions in the motif may present routes to clear persistent infections or limit immunopathology

Interferon at the cellular, individual, and population level in hepatitis C virus infection: Its role in the interferon-free treatment era

The advent of powerful direct-acting antiviral agents (DAAs) has revolutionized the treatment of hepatitis C. DAAs cure nearly all patients with short duration, oral treatments. Significant efforts are now underway to optimize DAA-based treatments. We discuss the potential role of interferon in this optimization. Clinical studies present compelling evidence that DAAs perform better in treatment-naive individuals than in individuals who previously failed treatment with interferon, a surprising correlation because interferon and DAAs are thought to act independently. Recent mathematical models explore a mechanistic hypothesis underlying this correlation. The hypothesis invokes the action of interferon at the cellular, individual, and population levels. Strong interferon responses prevent the productive infection of cells, reduce viral replication, and impede the development of resistance to DAAs in infected individuals and improve cure rates elicited by DAAs in treated populations. The models develop descriptions of these processes, integrate them into a comprehensive framework, and capture clinical data quantitatively, providing a successful test of the hypothesis. Individuals with strong endogenous interferon responses thus present a promising subpopulation for reducing DAA treatment durations. This review discusses the conceptual advances made by the models, highlights the new insights they unravel, and examines their applicability to optimize DAA-based treatments

Modeling how reversal of immune exhaustion elicits cure of chronic hepatitis C after the end of treatment with direct-acting antiviral agents

A fraction of chronic hepatitis C patients treated with direct-acting antivirals (DAAs) achieved sustained virological responses (SVR), or cure, despite having detectable viremia at the end of treatment (EOT). This observation, termed EOT+/SVR, remains puzzling and precludes rational optimization of treatment durations. One hypothesis to explain EOT+/SVR, the immunologic hypothesis, argues that the viral decline induced by DAAs during treatment reverses the exhaustion of cytotoxic T lymphocytes (CTLs), which then clear the infection after treatment. Whether the hypothesis is consistent with data of viral load changes in patients who experienced EOT+/SVR is unknown. Here, we constructed a mathematical model of viral kinetics incorporating the immunologic hypothesis and compared its predictions with patient data. We found the predictions to be in quantitative agreement with patient data. Using the model, we unraveled an underlying bistability that gives rise to EOT+/SVR and presents a new avenue to optimize treatment durations. Infected cells trigger both activation and exhaustion of CTLs. CTLs in turn kill infected cells. Due to these competing interactions, two stable steady states, chronic infection and viral clearance, emerge, separated by an unstable steady state with intermediate viremia. When treatment during chronic infection drives viremia sufficiently below the unstable state, spontaneous viral clearance results post-treatment, marking EOT+/SVR. The duration to achieve this desired reduction in viremia defines the minimum treatment duration required for ensuring SVR, which our model can quantify. Estimating parameters defining the CTL response of individuals to HCV infection would enable the application of our model to personalize treatment durations

A fluorescent gold-cluster containing a new three-component system for white light emission through a cascade of energy transfer

Fluorescent gold clusters (blue emitter) have been judiciously utilized to initiate an energy transfer process as a donor to the green emitting riboflavin (acceptor) and then riboflavin relays the energy transfer to the red emitting dye Rhodamine B in a controlled fashion to generate white light emission in a novel three component system (gold cluster, riboflavin and Rhodamine B). The CIE coordinate of (0.32, 0.35) has been achieved for the white light emitting solution. The solution processable white light emitting material has been prepared using a non-toxic, eco-friendly solvent, in the aqueous medium. It can be soaked or coated over a solid surface to generate white light emission. Writing can also be achieved on the silica surface by using this new white light emitting eco-friendly solution

Blue Emitting Gold Cluster formation from Gold Nanorods: Selective and Sensitive Detection of Iron(III) ions in Aqueous Medium

Fluorescent few-atom gold quantum clusters from gold nanorods have been synthesized through core–etching method in an aqueous medium in the presence of a bioactive peptide, glutathione (reduced), as the stabilizing agent. These gold clusters emit blue light under irradiation with a 365 nm wavelength UV-torch and exhibit emission maxima at 425 nm in water. Interestingly, this blue emitting gold cluster has been successfully used for the sensitive and selective fluorometric detection of Fe­(III) in the presence of other interfering ions including Pb­(II), Zn­(II), Ca­(II), Hg­(II), Cr­(III), Co­(II), As­(III), Ni­(II), Mn­(II), Mg­(II), and Al­(III) in an aqueous medium. Moreover, the blue emitting gold quantum cluster is selective to Fe­(III) but not to Fe­(II) ions in water. The ratio of Fe­(II)/ Fe­(III) ions in aqueous medium has also been determined, suggesting the probable use of this method in real iron-rich systems. Furthermore, the sensor can also be reused several times by removing Fe­(III) with sulfide ions

A peptide-based mechano-sensitive, proteolytically stable hydrogel with remarkable antibacterial properties

A long-chain amino acid containing dipeptide has been found to form a hydrogel in phosphate buffer whose pH ranges from 6.0 to 8.8. The hydrogel formed at pH 7.46 has been characterized by small-angle X-ray scattering (SAXS), wide-angle powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM) imaging and rheological analyses. The microscopic imaging studies suggest the formation of a nanofibrillar three-dimensional (3D) network for the hydrogel. As observed visually and confirmed rheologically, the hydrogel at pH 7.46 exhibits thixotropy. This thixotropic property can be exploited to inject the peptide. Furthermore, the hydrogel exhibits remarkable antibacterial activity against Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, which are responsible for many common diseases. The hydrogel has practical applicability due to its biocompatibility with human red blood cells and human fibroblast cells. Interestingly, this hydrogel shows high resistance toward proteolytic enzymes, making it a new potential antimicrobial agent for future applications. It has also been observed that a small change in molecular structure of the gelator peptide not only turns the gelator into a nongelator molecule under similar conditions, but it also has a significant negative impact on its bactericidal character

Assembly of an Injectable Noncytotoxic Peptide-Based Hydrogelator for Sustained Release of Drugs

A new synthetic tripeptide-based hydrogel has been discovered at physiological pH and temperature. This hydrogel has been thoroughly characterized using different techniques including field emission scanning electron microscopic (FE-SEM) and high-resolution transmission electron microscopic (HR-TEM) imaging, small- and wide-angle X-ray diffraction analyses, FT-IR, circular dichroism, and rheometric analyses. Moreover, this gel exhibits thixotropy and injectability. This hydrogel has been used for entrapment and sustained release of an antibiotic vancomycin and vitamin B₁₂ at physiological pH and temperature for about 2 days. Interestingly, MTT assay of these gelator molecules shows almost 100% cell viability of this peptide gelator, indicating its noncytotoxicity