Simulation and Fabrication of Stronger,Larger, and Faster Walking Biohybrid Machines

Advancing biologically driven soft robotics and actuators will involve employing different scaffold geometries and cellular constructs to enable a controllable emergence for increased production of force. By using hydrogel scaffolds and muscle tissue, soft biological robotic actuators that are capable of motility have been successfully engineered with varying morphologies. Having the flexibility of altering geometry while ensuring tissue viability can enable advancing functional output from these machines through the implementation of new construction concepts and fabrication approaches. This study reports a forward engineering approach to computationally design the next generation of biological machines via direct numerical simulations. This was subsequently followed by fabrication and characterization of high force producing biological machines. These biological machines show millinewton forces capable of driving locomotion at speeds above 0.5 mm s^?1. It is important to note that these results are predicted by computational simulations, ultimately showing excellent agreement of the predictive models and experimental results, further providing the ability to forward design future generations of these biological machines. This study aims to develop the building blocks and modular technologies capable of scaling force and complexity of these devices for applications toward solving real world problems in medicine, environment, and manufacturing.     

Spectrophotometric determination of acetone in acetic acid

A sensitive and selective spectrophotometric method for the determination of acetone in acetic acid has been worked out. It is based on the reaction of acetone with diazotized p-aminobenzoic acid in a strongly alkaline medium to form a purple color with maximum absorption at 540 nm. Beer's law holds up in the range 20–140 μg of acetone in a final volume of 20 ml, with a molar absorptivity of 8.1 × 10³ liters mol^?1 cm^?1, sensitivity index of 0.0072 μg cm^?2, relative error of ?1.9 to +0.6%, and relative standard deviation of 0.7–3.5, depending on the concentration level. Furthermore, the color reaction is fast, and the procedure is simple, and avoids the use of an extraction.     

Matrix-assisted laser desorption/ionization mass spectrometry with re-engineered 2,5-dihydroxybenzoic acid derivative

Dihydroxybenzoic acid was modified to three analogues (M2, M4 and M6). The analogues exhibited specific properties that resulted in enhancement of analyte signal intensity with or without addition of iodine compared to the underivatized parent. Addition of iodine to M2, an ester of dihydroxybenzoic acid that had a terminal double bond in the alkyl chain, resulted in peak intensities comparable to the parent, indicating that iodine interaction across the double bond resulted in enhancement although the exact mechanism is not fully understood. No enhancement on addition of iodine was observed for M4, which had a long alkyl chain that contained no double bonds. The alkyl chain allowed micelle formation in solution, which in turn allowed more uniform analyte-to-matrix mixing. The final analogue combined the long alkyl chain of M4 with the double bond of M2 and exhibited either similar peak intensities to that of dihydroxybenzoic acid or better. Micelle formation in solution was examined using spectroscopy and in the solid by reflective microscopy. The standard deviation from spot to spot was considerably lower relative to dihydroxybenzoic acid (RSD 3.4%vs. 14.2%). Unlike dihydroxybenzoic acid, the novel matrix M6 was able to yield characteristic peaks for analytes such as ubiquitin.     

Characterisation of some exotic fruits (Morus nigra, Morus alba, Salvadora persica and Carissa opaca) used as herbal medicines by neutron activation analysis and estimation of their nutritional value

In the under developed countries, the people of far-flung rural areas still depend to a large extent upon herbal medicines. At the foundation of usage of herbal medicine is the experience of thousands of years. The present paper deals with the characterisation of exotic fruits for essential and toxic elements. The samples include Morus nigra, Morus alba, Salvadora persica and Carissa opaca (from low and high altitude). Two standardizations of neutron activation analysis, that is, semi-absolute k ₀-instrumental neutron activation analysis (k ₀-INAA) and epithermal neutron activation analysis (ENAA) were employed for the quantification of elements. The analysis methodologies were validated by analyzing the IAEA-336 (lichen) and NIST-SRM-1572 (citrus leaves). Sixteen elements including Br, Ca, Cl, Co, Cr, Fe, I, K, Mg, Mn, Na, Rb, Sb, Sc Sr, and Zn were determined in all samples. Daily intakes of various elements from the samples were measured and compared with the dietary reference intakes. Additionally, principal component analysis was performed to extract information regarding samples and elements.     

A study of the effect of the loss function on Bayes Estimate,posterior risk and hazard function for Lindley distribution

In this paper, mathematical properties of Lindley distribution via Bayesian approach are derived under different loss functions. These properties include: Bayes Estimators, posterior risks and failure rate function for simulation scheme. Elicitation of hyperparameters is also discussed. A real life application to waiting time data at the bank is also described for the developed procedures (also using WinBUGS). Results are compared on the basis of posterior risk.     

Control of Nanoscale Environment to Improve Stability of Immobilized Proteins on Diamond Surfaces

Immunoassays for detection of bacterial pathogens rely on the selectivity and stability of bio-recognition elements such as antibodies tethered to sensor surfaces. The search for novel surfaces that improve the stability of biomolecules and assay performance has been pursued for a long time. However, the anticipated improvements in stability have not been realized in practice under physiological conditions because the surface functionalization layers on commonly used substrates, silica and gold, are themselves unstable on time scales of days. In this paper, we show that covalent linking of antibodies to diamond surfaces leads to substantial improvements in biological activity of proteins as measured by the ability to selectively capture cells of the pathogenic bacterium Escherichia coli O157:H7 even after exposure to buffer solutions at 37 °C for extended periods of time, approaching 2 weeks. Our results from ELISA, XPS, fluorescence microscopy, and MD simulations suggest that by using highly stable surface chemistry and controlling the nanoscale organization of the antibodies on the surface, it is possible to achieve significant improvements in biological activity and stability. Our findings can be easily extended to functionalization of micro and nanodimensional sensors and structures of biomedical diagnostic and therapeutic interest.     

Stretching a Curved Surface in a Viscous Fluid

This work is concerned with the viscous flow due to a curved stretching sheet. The similarity solution of the problem is obtained numerically by a shooting method using the Runge-Kutta algorithm. The physical quantities of interest like the fluid velocity and skin friction coefficient are obtained and discussed under the influence of dimensionless curvature. It is evident from the results that dimensionless curvature causes an increase in boundary layer thickness and a decrease in the skin friction coefficient.     

Use of Enzymatic Digestion and Chemical Methylation Followed by Matrix-assisted Laser Desorption/Ionisation (MALDI) Mass Spectrometry to Sequence a 60kDa Commercial Fraction of Cellulose Acetate

Cellulose acetate was characterized by using enzyme in both digestion and chemical derivation and acetolysis. The fragments were normalised and compared on an anhydroglucose scale, using mass spectrometry to identify the different sized fragments. It was determined that at least two sub-populations for cellulose acetate existed within the parent. The macroscopic effect of this variation in the degree of acetylation will be a modification of the structural properties of the polymer chains. It was found that through comparison with enzyme-based degradation, an estimation of the acetylation topography of the cellulose acetate fraction could be made. Enzyme degradation produced a number of oligosaccharides of more than 10 glucose units, presumably resistant to enzyme degradation because they contained acetate groups. Chemical hydrolysis gave a random ladder of short sequences of mainly 3–4 glucose units some of which had a high methyl ether content, that were analysed by mass and converted to an anhydroglucose mass scale. This approach could be used to demonstrate differences between large biopolymers of cellulose acetate that previously gave an overall average rather than a specific ladder average.