As the world's population is expected to be over 2/3.sup.rd urban by 2050, climate action in cities is a growing area of interest in the inter-disciplines of development policy, disaster mitigation ...and environmental governance. The climate impacts are expected to be quite severe in the developing world, given its urban societies are densely packed, vastly exposed to natural elements while possessing limited capabilities. There is a notable ambiguity and complexity that inhibits a methodical approach in identifying urban resilience measures. The complexity is due to intersection of large number of distinct variables in climate geoscience (precipitation and temperature anomalies at different locations, RCPs, timeline), adaptation alternatives (approach, priority, intervention level) and urban governance (functional mandate, institutional capacity, and plans & policies). This research examines how disparate and complex knowledge and information in these inter-disciplines can be processed for systematic 'negotiation' to situate, ground and operationalize resilience in cities. With India as a case, we test this by simulating mid-term and long-run climate scenarios (2050 & 2080) to map regional climate impacts that shows escalation in the intensity of climate events like heat waves, urban flooding, landslides and sea level rise. We draw on suitable adaptation measures for five key urban sectors- water, infrastructure (including energy), building, urban planning, health and conclude a sleuth of climate resilience building measures for policy application through national/ state policies, local urban plans and preparation of city resilience strategy, as well as advance the research on 'negotiated resilience' in urban areas
In recent times, several control engineers have been working towards development of efficient rehabilitation exoskeletons for mobility impairments. This work aims at implementation of an optimal ...fuzzy logic-based control strategy for a lower limb exoskeleton application wherein the control parameters for the proposed control approach are obtained by a recently developed optimization technique named as dragon fly algorithm (DFA). For analysis of appropriately tuned closed-loop control, a comparative study between two optimization techniques namely DFA and genetic algorithm (GA) applied to a 2-degree of freedom (dof) nonlinear and coupled lower-limb exoskeleton, is presented. To see the practical aspects, a three-dimensional simscape model of the 4-dof lower limb exoskeleton is developed to observe the closed-loop performance of fuzzy logic proportional–integral–derivative (FLC-PID) controller for bipedal human walking. Experimental data for different speeds during treadmill walking is captured with electronic wireless goniometer, and is used to validate the bipedal walking control for the designed lower-limb exoskeleton. The results are further compared with traditional PID controllers in order to see the effectiveness of the proposed control approaches. Furthermore, the robustness testing of the proposed control schemes is also investigated for different speeds of human walking. This study presents a closed-loop control design for the development of a low-cost lower limb exoskeleton to restore normal gait for persons with mobility disorders, stroke or elderly persons.
•To design a fuzzy-logic based control strategy for the lower limb exoskeleton.•Dragonfly algorithm is used for obtaining the parameters of proposed control approaches.•To see practical applicability, a closed-loop 4-degree of freedom (dof) lower limb exoskeleton is developed.•Experimental data for bipedal walking for healthy person using wireless goniometer is captured.•Finally, the robustness testing for the proposed control strategy is investigated for walking at different speeds.
The cellular uptake and expulsion rates of length-fractionated single-walled carbon nanotubes (SWNT) from 130 to 660 nm in NIH-3T3 cells were measured via single particle tracking of their intrinsic ...photoluminescence. We develop a quantitative model to correlate endocytosis rate with nanoparticle geometry that accurately describes this data set and also literature results for Au nanoparticles. The model asserts that nanoparticles cluster on the cell membrane to form a size sufficient to generate a large enough enthalpic contribution via receptor ligand interactions to overcome the elastic energy and entropic barriers associated with vesicle formation. Interestingly, the endocytosis rate constant of SWNT (10−3 min−1) is found to be nearly 1000 times that of Au nanoparticles (10−6 min−1) but the recycling (exocytosis) rate constants are similar in magnitude (10−4 to 10−3 min−1) for poly(d,l-lactide-co-glycolide), SWNT, and Au nanoparticles across distinct cell lines. The total uptake of both SWNT and Au nanoparticles is maximal at a common radius of 25 nm when scaled using an effective capture dimension for membrane diffusion. The ability to understand and predict the cellular uptake of nanoparticles quantitatively should find utility in designing nanosystems with controlled toxicity, efficacy, and functionality.
The reactivity of graphene and its various multilayers toward electron transfer chemistries with 4-nitrobenzene diazonium tetrafluoroborate is probed by Raman spectroscopy after reaction on-chip. ...Single graphene sheets are found to be almost 10 times more reactive than bi- or multilayers of graphene according to the relative disorder (D) peak in the Raman spectrum examined before and after chemical reaction in water. A model whereby electron puddles that shift the Dirac point locally to values below the Fermi level is consistent with the reactivity difference. Because the chemistry at the graphene edge is important for controlling its electronic properties, particularly in ribbon form, we have developed a spectroscopic test to examine the relative reactivity of graphene edges versus the bulk. We show, for the first time, that the reactivity of edges is at least two times higher than the reactivity of the bulk single graphene sheet, as supported by electron transfer theory. These differences in electron transfer rates may be important for selecting and manipulating graphitic materials on-chip.
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•Aptamer hybridized with fluorophore- & quencher-oligomer to construct molecular beacon.•Quencher-oligomer desorbed on addition of chloramphenicol, turning signal on.•Immobilized ...aptamer & removal of desorbed fluorophore-oligomer improve resolution.•Background quenching removed, leading to very low detection limit in honey samples.
Chloramphenicol is a potent drug used to treat a variety of bacterial infections. However, due to its toxic effects on human health, use of chloramphenicol is banned in food-producing animals, emphasizing the necessity for its ultrasensitive detection. A molecular beacon-based fluorescent sensing method was developed for the purpose. Fluorophore- and quencher-tagged oligonucleotides complementary to aptamer recognising chloramphenicol were hybridized to construct an aptaswitch sensor complex. On analyte binding the fluorescence was turned on, due to desorption of quencher-oligonucleotide from the complex. With optimized concentrations, the linear range of detection was observed to be from 10 pg mL−1 to 107 pg mL-1 of CAP and LOD in buffer was estimated to be 0.987 pg mL−1. In a modified fluorescence turn-off approach, the aptamers were immobilized through maleimide chemistry on microplates to improve detection limit and resolution. In this format, only fluorophore-oligonucleotide was hybridized to the aptamer which could be detached in presence of chloramphenicol, turning the aptaswitch off. This oligonucleotide was removed to avoid background interference leading to higher resolution and sensitive detection (detection limit 0.039 pg mL−1), with a linear range from 1 pg mL-1 to 104 pg mL−1 and regression coefficient 0.99. The performance of the aptaswitch sensor was tested in real honey samples where it showed excellent reproducibility, selectivity, accuracy and a detection limit of 0.285 pg mL−1, which is considerably lower than previously reported biosensors.
Keratinases are special proteases which attack the highly recalcitrant keratin substrates. They stand apart from the conventional proteases due to their broad substrate specificity towards a variety ...of insoluble keratin rich substrates like feather, wool, nail, hair. Owing to this ability, keratinases find immense applications in various environmental and biotechnological sectors. The current boost in keratinase research has come up with the discovery of the ability of keratinases to address the challenging issue of prion decontamination. Here we present a comprehensive review on microbial keratinases giving an account of chronological progress of research along with the major milestones. Major focus has been on the key characteristics of keratinases, such as substrate specificity, keratin degradation mechanisms, molecular properties, and their role in prion decontamination along with other pharmaceutical applications. We conclude by critically evaluating the present state of the keratinases discussing their commercial status along with future research directions.
Multiferroic particulate composites comprising BaTiO3 as ferroelectric phase and CoFe1.8Zn0.2O4 as ferrite phase with the formula (1−x) BaTiO3–(x) CoFe1.8Zn0.2O4 (where x=10, 20, 30 and 40wt%) are ...fabricated by the solid state reaction method. To check the phase purity and structure formation, X-ray diffraction (XRD) technique has been used. XRD patterns confirm the formation of the individual phases and the composites. Using scanning electron microscopy (SEM), the morphology of the composites is studied and reveals an increase in grain size with ferrite content. In addition, significant effect of ferrite content on the dielectric, electric and magnetic properties of the composites has also been observed. Variation of dielectric constant (ε׳) and loss tangent (tan δ) with temperature (up to 400°C) and frequency (20Hz–1MHz) have been investigated. Dielectric constant is found to increase as ferrite fraction increases with the appearance of two peaks, one in the lower temperature region and other in the higher temperature region. Peak observed in the low temperature range (120°C–150°C) is ascribed to ferroelectric to paraelectric phase transition of the BaTiO3 phase. The increase in dielectric constant can be attributed to the space charge effect and the hopping conduction mechanism. Besides this, the variation of loss tangent (tan δ) with temperature of the composites exhibits loss peaks. With increasing frequency, all the composites show usual dielectric dispersion. AC conductivity of the composites has been studied as a function of frequency and temperature to understand the conduction mechanism. The observed behavior of the conductivity can be interpreted using a jump relaxation model (JRM). Polarization (P) vs. Electric field (E) and Magnetization(M) vs. Magnetic field (H) loops are measured at room temperature which demonstrates that all the composites exhibit simultaneously good ferroelectric and ferromagnetic properties.
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