274 research outputs found

    Low Complexity Blind Equalization for OFDM Systems with General Constellations

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    This paper proposes a low-complexity algorithm for blind equalization of data in OFDM-based wireless systems with general constellations. The proposed algorithm is able to recover data even when the channel changes on a symbol-by-symbol basis, making it suitable for fast fading channels. The proposed algorithm does not require any statistical information of the channel and thus does not suffer from latency normally associated with blind methods. We also demonstrate how to reduce the complexity of the algorithm, which becomes especially low at high SNR. Specifically, we show that in the high SNR regime, the number of operations is of the order O(LN), where L is the cyclic prefix length and N is the total number of subcarriers. Simulation results confirm the favorable performance of our algorithm

    Isolated ligamentum flavum ossification in primary hypoparathyroidism

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    Basckground: The ligamenta flava can undergo ossification and calcification resulting in myelopathy. Only seven cases of ligamentumflavum ossification in association with hypoparathyroidism have been reported, most of which had concurrent osseous changes in other spinal ligaments. Here, we report a patient with hypoparathyroidism who presented ith ligamentum flavum ossification causing both cervical and thoracic myelopathy. Case description: A 43-year-old male presented with backache, urinary retention, and lower limb weakness for the last few days. Magnetic resonance imaging scan showed ossification of the ligamentum flavum in the cervical and thoracic regions, with severe spinal stenosis. Following spinal decompressive surgery, the patient made a complete recovery. Primary hypoparathyroidism was found to be the underlying cause for ligamentum flavum ossification. Conclusion: Ossification of ligamentum flavum secondary to hypoparathyroidism should be considered as a possible cause of myelopathy in all patients presenting with symptoms of spinal cord compression

    Forecasting the Stochastic Vicious Cycle of Cancer Progression and Immune Response

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    It is accepted that cancer progression is a stochastic process, and there is a bifurcation in cancer cell count, which gets chaotic if not treated at preliminary stages. Therefore, strategies for fighting cancer at early stages are highly desired. However, the interaction of the immune system with cancer cells is not a straightforward process. The stochastic cell interactions lead to uncontrollable dynamics and sometimes to the death of the patient. A stochastic computational framework developed based on principles of the cancer-immune cell interaction is proposed in this article. The results obtained using the framework for breast cancer are close to the experimental findings, confirming that it can be a useful tool for identifying possible control measures. This study concludes that a control strategy based on stochastic modeling is promising and that a deep understanding of the interaction cell rates is essential for timely cancer control measures. (c) 2021 The Author(s

    Suitability of various plant derived gelling agents as agar substitute in microbiological growth media

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    Eleven putative gelling agents were investigated as agar substitutes. These included arrowroot (Maranta arundinaceae), coconut powder (Cocos nucifera), corn flour (Zea mays var. amylacea), gel rite (a water-soluble polysaccharide produced by Sphingomonas elodea), glue (Cyanoacrylates), katira gum (Cochlospermum religiosum), guar gum (Cyamopsis tetragonolobus L.), isubgol husk (Plantago ovata), pectin and rice (Oryza sativa L.) powder. Among these, guar gum was found a promising alternate candidate for agar. Media solidified with 2.8% guar gum was transparent and supportive for the growth of three test fungi (Trichoderma harzianum, Alternaria alternata and Alternaria solani) as good as agar. Guar gum also excelled in terms of cost benefit ratio when compared with agar. Guar gum fortified media was found to cost 0.005/Lascomparedtoagarsupplementedmediacosting 0.005/L as compared to agar supplemented media costing 1.17/L. Further, guar gum is easily available and can be added with ease thereby serving as a suitable and inexpensive substitute of agar and thus, can be adopted for routine microbiological testing in resource poor countries.Key words: Guar gum, media, agar, gelling agents

    Heat induction in two-dimensional graphene–Fe3O4 nanohybrids for magnetic hyperthermia applications with artificial neural network modeling

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    We report the synthesis and characterization of graphene functionalized with iron (Fe3+) oxide (G-Fe3O4) nanohybrids for radio-frequency magnetic hyperthermia application. We adopted the wet chemical procedure, using various contents of Fe3O4 (magnetite) from 0–100% for making two-dimensional graphene–Fe3O4 nanohybrids. The homogeneous dispersal of Fe3O4 nanoparticles decorated on the graphene surface combined with their biocompatibility and high thermal conductivity make them an excellent material for magnetic hyperthermia. The morphological and magnetic properties of the nanohybrids were studied using scanning electron microscopy (SEM) and a vibrating sample magnetometer (VSM), respectively. The smart magnetic platforms were exposed to an alternating current (AC) magnetic field of 633 kHz and of strength 9.1 mT for studying their hyperthermic performance. The localized antitumor effects were investigated with artificial neural network modeling. A neural net time-series model was developed for the assessment of the best nanohybrid composition to serve the purpose with an accuracy close to 100%. Six Nonlinear Autoregressive with External Input (NARX) models were obtained, one for each of the components. The assessment of the accuracy of the predicted results has been done on the basis of Mean Squared Error (MSE). The highest Mean Squared Error value was obtained for the nanohybrid containing 45% magnetite and 55% graphene (F45G55) in the training phase i.e., 0.44703, which is where the model achieved optimal results after 71 epochs. The F45G55 nanohybrid was found to be the best for hyperthermia applications in low dosage with the highest specific absorption rate (SAR) and mean squared error values

    Development of Paracetamol-Caffeine co-crystals to improve compressional, formulation and in-vivo performance

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    Paracetamol, a frequently used antipyretic and analgesic drug, has poor compression moldability owing to its low plasticity. In this study, new co-crystals of paracetamol (PCM) with caffeine (as a co-former) were prepared and delineated. Co-crystals exhibited improved compaction and mechanical behavior. A screening study was performed by utilizing a number of methods namely dry grinding, liquid assisted grinding (LAG), solvent evaporation (SE) and anti-solvent addition using various weight ratios of starting materials. LAG and SE were found successful in the screening study. Powders at 1:1 and 2:1 weight ratio of PCM/CAF by LAG and SE respectively resulted in the formation of co-crystals. Samples were characterized by PXRD, DSC and ATR-FTIR techniques. Compressional properties of PCM and developed co-crystals were analyzed by in-die heckle model. Mean yield pressure (Py), an inverse measure of plasticity, obtained from the heckle plots decreased significantly (p<0.05) for co-crystals than pure drug. Intrinsic dissolution profile of co-crystals showed up to 2.84 fold faster dissolution than PCM and physical mixtures in phosphate buffer pH 6.8 at 37 oC. In addition co-crystals formulated into tablets by direct compression method showed better mechanical properties like hardness and tensile strength. In vitro dissolution studies on tablets also showed enhanced dissolution profiles (~90- 97%) in comparison to the tablets of PCM prepared by direct compression (~55%) and wet granulation (~85%) methods. In a single dose sheep model study co-crystals showed up to two fold increase in AUC and Cmax. A significant (p < 0.05) decrease in clearance as compared to pure drug was also recorded. In conclusion new co-crystals of PCM were successfully prepared with improved tabletability in-vitro and in-vivo profile. Enhancement in AUC and Cmax of PCM by co-crystallisation might suggest the dose reduction and avoidance of side effects

    The Fecal Microbiome in Cats with Diarrhea

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    Recent studies have revealed that microbes play an important role in the pathogenesis of gastrointestinal (GI) diseases in various animal species, but only limited data is available about the microbiome in cats with GI disease. The aim of this study was to evaluate the fecal microbiome in cats with diarrhea. Fecal samples were obtained from healthy cats (n = 21) and cats with acute (n = 19) or chronic diarrhea (n = 29) and analyzed by sequencing of 16S rRNA genes, and PICRUSt was used to predict the functional gene content of the microbiome. Linear discriminant analysis (LDA) effect size (LEfSe) revealed significant differences in bacterial groups between healthy cats and cats with diarrhea. The order Burkholderiales, the families Enterobacteriaceae, and the genera Streptococcus and Collinsella were significantly increased in diarrheic cats. In contrast the order Campylobacterales, the family Bacteroidaceae, and the genera Megamonas, Helicobacter, and Roseburia were significantly increased in healthy cats. Phylum Bacteroidetes was significantly decreased in cats with chronic diarrhea (>21 days duration), while the class Erysipelotrichi and the genus Lactobacillus were significantly decreased in cats with acute diarrhea. The observed changes in bacterial groups were accompanied by significant differences in functional gene contents: metabolism of fatty acids, biosynthesis of glycosphingolipids, metabolism of biotin, metabolism of tryptophan, and ascorbate and aldarate metabolism, were all significantly (p<0.001) altered in cats with diarrhea. In conclusion, significant differences in the fecal microbiomes between healthy cats and cats with diarrhea were identified. This dysbiosis was accompanied by changes in bacterial functional gene categories. Future studies are warranted to evaluate if these microbial changes correlate with changes in fecal concentrations of microbial metabolites in cats with diarrhea for the identification of potential diagnostic or therapeutic targets.The open access fee for this work was funded through the Texas A&M University Open Access to Knowledge (OAK) Fund
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