49 research outputs found

    Concentration of Submodular Functions Under Negative Dependence

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    We study the question of whether submodular functions of random variables satisfying various notions of negative dependence satisfy Chernoff-like concentration inequalities. We prove such a concentration inequality for the lower tail when the random variables satisfy negative association or negative regression, resolving an open problem raised in (\citet{approx/QiuS22}). Previous work showed such concentration results for random variables that come from specific dependent-rounding algorithms (\citet{focs/ChekuriVZ10,soda/HarveyO14}). We discuss some applications of our results to combinatorial optimization and beyond.Comment: 12 page

    An Efficient Identity-Based Signcryption Scheme for Multiple Receivers

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    This paper puts forward a new efficient construction for Multi-Receiver Signcryption in the Identity-based setting. We consider a scenario where a user wants to securely send a message to a dynamically changing subset of the receivers in such a way that non-members of the of this subset cannot learn the message. The obvious solution is to transmit an individually signcrypted message to every member of the subset. This requires a very long transmission (the number of receivers times the length of the message) and high computation cost. Another simple solution is to provide every possible subset of receivers with a key. This requires every user to store a huge number of keys. In this case, the storage efficiency is compromised. The goal of this paper is to provide solutions which are efficient in all three measures i.e. transmission length, storage of keys and computation at both ends. We propose a new scheme that achieve both confidentiality and authenticity simultaneously in this setting and is the most efficient scheme to date, in the parameters described above. It breaks the barrier of ciphertext length of linear order in the number of receivers, and achieves constant sized ciphertext, independent of the size of the receiver set. This is the first Multi-receiver Signcryption scheme to do so. We support the scheme with security proofs under a precisely defined formal security mode

    The human Discs large protein (Dlg1) interacts with and maintains Connexin 43 at the plasma membrane in keratinocytes

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    Gap junction channels, composed of connexins, allow direct cell-to-cell communication. Connexin 43 (Cx43) is widely expressed in tissues, including the epidermis. In a previous study of human papillomavirus-positive cervical epithelial tumour cells, we identified Cx43 as a binding partner of the human homologue of Drosophila Discs large (Dlg1). Dlg1 is a member of the membrane associated-guanylate kinase (MAGUK) scaffolding protein family that is known to control cell shape and polarity. Here we show that Cx43 also interacts with Dlg1 in uninfected keratinocytes in vitro and in keratinocytes, dermal cells and adipocytes in normal human epidermis in vivo. Depletion of Dlg1 in keratinocytes did not alter Cx43 transcription but was associated with a reduction in Cx43 protein levels. Reduced Dlg1 levels in keratinocytes resulted in a reduction in Cx43 at the plasma membrane with a concomitant reduction in gap junctional intercellular communication and relocation of Cx43 to the Golgi compartment. Our data suggest a key role for Dlg1 in maintaining Cx43 at the plasma membrane in keratinocytes

    FORMULATION AND EVALUATION OF CEFIXIME TRIHYDRATE TOPICAL GEL FOR WOUND INFECTIONS

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    Objective: The objective of this research work was to formulate and evaluate topical gel loaded with cefixime trihydrate, a third-generation cephalosporin antibiotic for the treatment of bacterial wound infections.Methods: The cefixime trihydrate gel was formulated using polymers such as Carbopol 940 and hydroxypropyl methylcellulose E4M in varying concentrations. Three different formulations were prepared and characterized physically for color, syneresis, spreadability, pH, drug content, and rheological properties. In vitro drug release in phosphate buffer pH 7.4 and antibacterial study were performed for the gel formulation to evaluate its therapeutic effect on wound infections.Results: The study demonstrated that the gel formulations showed promising results on their physical evaluation tests. The rheology behavior of the gel was shear-thinning flow type which indicated easy spreading of the gel. The drug release of the gel formulation F2 was selected as the best due to its highest drug release rate of 32.2% in comparison with the other two formulations after 2 h of the study. F2 formulation possessed the highest antibacterial activity as compared to other two formulations.Conclusion: A pioneering work was done on formulating cefixime trihydrate as a gel for topical administration. The antibacterial effect of the drug as gel formulation showed promising effect. We conclude that the cefixime trihydrate could be successively loaded into a gel formulation and can be used for effectively for wound infections like diabetic foot wounds

    Formulation of essential oil-loaded chitosan–alginate nanocapsules

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    Naturally occurring polymers such as alginate (AL) and chitosan (CS) are widely used in biomedical and pharmaceutical fields in various forms such as nanoparticles, capsules, and emulsions. These polymers have attractive applications in drug delivery because of their biodegradability, biocompatibility, and nontoxic nature. The pharmaceutical applications of essential oils such as turmeric oil and lemongrass oil are well-known, and their active components, ar-turmerone and citral, respectively, are known for their antibacterial, antifungal, antioxidant, antimutagenic, and anticarcinogenic properties. However, these essential oils are unstable, volatile, and insoluble in water, which limits their use for new formulations. Therefore, this study focuses on developing a CS–AL nanocarrier for the encapsulation of essential oils. The effects of process parameters such as the effect of heat and the concentrations of AL and CS were investigated. Various physicochemical characterization techniques such as scanning electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy were performed. Results of characterization studies showed that 0.3 mg/mL AL and 0.6 mg/mL CS produced minimum-sized particles (<300 nm) with good stability. It was also confirmed that the oil-loaded nanocapsules were hemocompatible, suggesting their use for future biomedical and pharmaceutical applications. Furthermore, the antiproliferative activity of turmeric oil- and lemongrass oil-loaded nanocapsules was estimated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay in A549 cell lines and it was found that both the nanoformulations had significant antiproliferative properties than the bare oil

    Ecolocation: A sequence based technique for RF localization in wireless sensor networks

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    Abstract — In this paper we present a novel sequence-based RF localization algorithm called Ecolocation. Our algorithm determines the location of unknown nodes by examining the ordered sequence of received signal strength (RSS) measurements taken at multiple reference nodes. We employ a constraint-based approach that provides for robust location decoding even in the presence of random RSS fluctuations due to multipath fading and shadowing. Through extensive systematic simulations, and a representative set of real mote experiments, we show that over a wide range of settings Ecolocation performs better than other state of the art approaches in terms of localization accuracy and precision. I
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