110 research outputs found

    Memoryless nonlinear response: A simple mechanism for the 1/f noise

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    Discovering the mechanism underlying the ubiquity of "1/fα""1/f^{\alpha}" noise has been a long--standing problem. The wide range of systems in which the fluctuations show the implied long--time correlations suggests the existence of some simple and general mechanism that is independent of the details of any specific system. We argue here that a {\it memoryless nonlinear response} suffices to explain the observed non--trivial values of α\alpha: a random input noisy signal S(t)S(t) with a power spectrum varying as 1/fα′1/f^{\alpha'}, when fed to an element with such a response function RR gives an output R(S(t))R(S(t)) that can have a power spectrum 1/fα1/f^{\alpha} with α<α′\alpha < \alpha'. As an illustrative example, we show that an input Brownian noise (α′=2\alpha'=2) acting on a device with a sigmoidal response function R(S)= \sgn(S)|S|^x, with x<1x<1, produces an output with α=3/2+x\alpha = 3/2 +x, for 0≤x≤1/20 \leq x \leq 1/2. Our discussion is easily extended to more general types of input noise as well as more general response functions.Comment: 5 pages, 5 figure

    Power spectrum of mass and activity fluctuations in a sandpile

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    We consider a directed abelian sandpile on a strip of size 2×n2\times n, driven by adding a grain randomly at the left boundary after every TT time-steps. We establish the exact equivalence of the problem of mass fluctuations in the steady state and the number of zeroes in the ternary-base representation of the position of a random walker on a ring of size 3n3^n. We find that while the fluctuations of mass have a power spectrum that varies as 1/f1/f for frequencies in the range 3−2n≪f≪1/T 3^{-2n} \ll f \ll 1/T, the activity fluctuations in the same frequency range have a power spectrum that is linear in ff.Comment: 8 pages, 10 figure

    Biotechnological Potential of Agro Residues for Economical Production of Thermoalkali-Stable Pectinase by Bacillus pumilus dcsr1 by Solid-State Fermentation and Its Efficacy in the Treatment of Ramie Fibres

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    The production of a thermostable and highly alkaline pectinase by Bacillus pumilus dcsr1 was optimized in solid-state fermentation (SSF) and the impact of various treatments (chemical, enzymatic, and in combination) on the quality of ramie fibres was investigated. Maximum enzyme titer (348.0 ± 11.8 Ug −1 DBB) in SSF was attained, when a mixture of agro-residues (sesame oilseed cake, wheat bran, and citrus pectin, 1 : 1 : 0.01) was moistened with mineral salt solution (a w 0.92, pH 9.0) at a substrateto-moistening agent ratio of 1 : 2.5 and inoculated with 25% of 24 h old inoculum, in 144 h at 40 • C. Parametric optimization in SSF resulted in 1.7-fold enhancement in the enzyme production as compared to that recorded in unoptimized conditions. A 14.2-fold higher enzyme production was attained in SSF as compared to that in submerged fermentation (SmF). The treatment with the enzyme significantly improved tensile strength and Young&apos;s modulus, reduction in brittleness, redness and yellowness, and increase in the strength and brightness of ramie fibres

    A study on body mass index and its correlation with type 2 diabetes

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    Obesity and increases in body weight are among the most important risk factors for type 2 diabetes mellitus. Obesity contributes to the development of type 2 diabetes mellitus. Body mass index is also known as obesity index. Body mass index is a strong and independent risk factor for being diagnosed in cases of type 2 diabetes mellitus. There is a high risk of type 2 diabetes in those who have a higher body mass index. The present study has been done with the objective of finding correlation between BMI and type 2 diabetes

    Microwave Reflectometry As a Novel Diagnostic Tool for Detection of Skin Cancers

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    More than 1 000 000 people are diagnosed with skin cancer each year in the United States, and more than 10 000 people die from the disease. Methods such as visual inspection and dermoscopy are available for early detection of skin cancers, but improvement in accuracy is needed. This paper investigates the use of microwave reflectometry as a potential diagnostic tool for detection of skin cancers. Open-ended coaxial probes were used to measure microwave properties of skin. The influences of measurement parameters such as probe application pressure, power level, and variation in reflection properties of skin with location and hydration were investigated. Using an available electromagnetic formulation, providing for the reflection properties of a layered dielectric structure irradiated by a coaxial probe, measurement and simulation results were compared. The results of the measurements and simulations for normal and moistened skin show that the water content of normal skin and benign and malignant lesions may cause significant differences among their reflection properties and subsequently render a malignant lesion detectable. The results of microwave measurements performed on human subjects are also presented, which show the potential of this technique to distinguish between cancerous and benign lesions

    Investigating the effect of ligand and cation on the properties of metal fluorinated acetylacetonate based magnetic ionic liquids

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    Magnetic ionic liquids (MILs) are a subclass of ionic liquids that possess a paramagnetic metal within their chemical structure, making them susceptible to external magnetic fields. A total of twenty-four (24) MILs were prepared and characterized to investigate the effect of the ligand, cation and anion on the physiochemical properties of acetylacetonate-based MILs. It was found that thermal stabilities as high as 260 °C could be achieved by incorporating aromatic moieties in the anion structure. Additionally, the magnetic moment could be modulated by simply changing the transition metal in the anion. Magnetic moment values of 2.8 μB, 4.5 μBand 5.6 μB were obtained by using Ni(II), Co(II), and Mn(II) as the metal centers, respectively. Furthermore, the viscosity of the MILs could be tailored from a few hundred centipoise to several thousand centipoise, increasing their potential applications in numerous interdisciplinary fields. Moreover, the MILs synthesized in this study were found to be insoluble in water at a MIL-to-solvent ratio of 0.01% (w/v), making them potentially useful in targeted separations, where very hydrophobic solvents are highly desired

    Predicting the functional consequences of non-synonymous single nucleotide polymorphisms in IL8 gene

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    Here we report an in-silico approach for identification, characterization and validation of deleterious non-synonymous SNPs (nsSNPs) in the interleukin-8 gene using three steps. In first step, sequence homology-based genetic analysis of a set of 50 coding SNPs associated with 41 rsIDs using SIFT (Sorting Intolerant from Tolerant) and PROVEAN (Protein Variation Effect Analyzer) identified 23 nsSNPs to be putatively damaging/deleterious in at least one of the two tools used. Subsequently, structure-homology based PolyPhen-2 (Polymorphism Phenotyping) analysis predicted 9 of 23 nsSNPs (K4T, E31A, E31K, S41Y, I55N, P59L, P59S, L70P and V88D) to be damaging. According to the conditional hypothesis for the study, only nsSNPs that score damaging/deleterious prediction in both sequence and structural homology-based approach will be considered as 'high-confidence' nsSNPs. In step 2, based on conservation of amino acid residues, stability analysis, structural superimposition, RSMD and docking analysis, the possible structural-functional relationship was ascertained for high-confidence nsSNPs. Finally, in a separate analysis (step 3), the IL-8 deregulation has also appeared to be an important prognostic marker for detection of patients with gastric and lung cancer. This study, for the first time, provided in-depth insights on the effects of amino acid substitutions on IL-8 protein structure, function and disease association

    UTILIZATION OF SAMANYA SHODHANA IN THE PURIFICATION OF EXCESS MERCURY OBTAINED FROM DENTAL OPERATORY- A PRELIMINARY STUDY

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    Background: Concerns about toxicity of mercury and disposal of excessive mercury has led to decreased usage of mercury in dental profession but still tooth colored restorative materials are not affordable by all the classes of any society. The disposal of excess mercury has always been a matter of concern. Thus, in the present study, we attempted to evaluate a simple procedure from Rasa Shastra using lime powder, garlic and rock salt for recycling of excess mercury obtained from dental operatory.Materials and methods: The excess mercury was recycled by the standard procedure explained in Ayurveda texts (Samanya shodhana) using Sudha churna (lime powder), Lashuna kalka (paste of Allium sativum L.) and Saindhava lavanaa (rock salt). The commercially available mercury and recycled mercury was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) for the detection of elements in ppm level.Results: It was found that the excess impure mercury contained 5138 ppm, 2866.1 ppm and 0.371 ppm of Silver, Copper and Tin respectively. After Shodhana, the level of silver, tin and copper were markedly reduced. Purified mercury showed a level of 119.5ppm silver, 0.5324 ppm copper and 0.3233 ppm tin.Conclusion: Samanya shodhana is a simple promising procedure which can be used for mercury recycling. The procedure doesnot require sophisticated equipments and maneuver. Further, the materials used in the procedure are easily available and affordable at low cost

    Magnetic ionic liquids based on transition metal complexes with N-alkylimidazole ligands

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    In this study, magnetic ionic liquids (MILs) consisting of Ni(II), Co(II), and Mn(II) and paired with the bis[(trifluoromethyl)sulfonyl]imide [NTf2−] anion were synthesized from their water soluble chloride intermediates. The MILs feature low viscosity, high hydrophobicity, and hydrolytic stability making them attractive candidates for a number of highly interdisciplinary applications
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