Effect of ion exchange resin on increased surface area crystallization process for purification of vancomycin

We investigated the effects of ion exchange resins on the efficiency of crystallization with an increased surface area for the purification of vancomycin. As surface area-increasing materials, diverse types of ion exchange resin were used to increase the surface area per working volume (S/V). When the S/V was increased, in cation exchange resin Amberlite 200, Amberlite IR 120 (Na), and Amberlite IRC 50 and in anion exchange resin Amberlite IRA 400 (Cl) and Amberlite IRA 910 (Cl), vancomycin crystals were successfully generated. The yield of vancomycin increased (>97%), and the time necessary for crystallization was reduced dramatically (reduced from 24 hr to 12 hr). On the other hand, the purity of the vancomycin was approximately 95% and was not affected by increasing S/V. Use of an ion exchange resin also resulted in the production of smaller vancomycin crystals than in the absence of ion exchange resin.     

Minimalist counting in sensor networks (Noise helps)

We propose a novel algorithm for counting N indistinguishable objects, called targets, by a collection of sensors. We adopt a minimalist scenario where sensors are unaware of the (non-empty) intersections of sensing regions, and so simple addition of all sensor counts inflates estimates of the total number of targets. The multiple counting in intersections must be accounted for, but with nothing more than the sensor counts, this is clearly impossible. However, noise is typically present in the target counting of many, if not most, applications. We make the key observation that if there is a (target-dependent) noise source affecting all sensors simultaneously, then it couples those with non-empty intersections. Exploitation of this coupling allows us to extract multiple-counting statistics from stochastic correlation patterns, and hence to compute accurate estimates of N via the classical inclusion–exclusion formula. Cumulants are the correlation measures of choice. Our analysis brings out and resolves certain technicalities that arise in our statistical counting algorithm. Examples are worked out to show the potential of the new algorithm. The paper concludes with a discussion of alternative models and open problems.     

High‐Performance Piezoelectric,Pyroelectric, and Triboelectric Nanogenerators Based on P(VDF‐TrFE) with Controlled Crystallinity and Dipole Alignment

Poly(vinylidenefluoride‐co‐trifluoroethylene) (P(VDF‐TrFE)), as a ferroelectric polymer, offers great promise for energy harvesting for flexible and wearable applications. Here, this paper shows that the choice of solvent used to dissolve the polymer significantly influences its properties in terms of energy harvesting. Indeed, the P(VDF‐TrFE) prepared using a high dipole moment solvent has higher piezoelectric and pyroelectric coefficients and triboelectric property. Such improvements are the result of higher crystallinity and better dipole alignment of the polymer prepared using a higher dipole moment solvent. Finite element method simulations confirm that the higher dipole moment results in higher piezoelectric, pyroelectric, and triboelectric potential distributions. Furthermore, P(VDF‐TrFE)‐based piezoelectric, pyroelectric, and triboelectric nanogenerators (NGs) experimentally validate that the higher dipole moment solvent significantly enhances the power output performance of the NGs; the improvement is about 24% and 82% in output voltage and current, respectively, for piezoelectric NG; about 40% and 35% in output voltage and current, respectively, for pyroelectric NG; and about 65% and 75% in output voltage and current for triboelectric NG. In brief, the approach of using a high dipole moment solvent is very promising for high output P(VDF‐TrFE)‐based wearable NGs.     

Routing Protocol for Heterogeneous Hierarchical Wireless Multimedia Sensor Networks

Recently, wireless multimedia sensor networks (WMSNs) have emerged as one of the most important technologies, driven by the development of powerful multimedia device such as CMOS. WMSNs require several factors such as resource constraints, specific QoS, high bandwidth and so on. In this paper, we propose a hierarchical heterogeneous network model based routing protocol for WMSNs. In our proposal, proposed network model is classified into monitoring class, delivery class and aggregation class. Also we define two kinds of the routing path in order to ensure bandwidth and QoS. In simulation results, we illustrate the performance of our proposal.     

Chirp‐Based Cognitive Ultra‐wideband Radio

In this letter, we propose a cognitive ultra‐wideband radio scheme which is based on a modified chirp waveform. Therefore, it requires only time domain processing in the cognitive radio systems and reduces system complexity and power consumption.     

Nanoscale adhesion,friction and wear studies of biomolecules on silane polymer-coated silica and alumina-based surfaces

Proteins on biomicroelectromechanical systems (BioMEMS) confer specific molecular functionalities. In planar FET sensors (field-effect transistors, a class of devices whose protein-sensing capabilities we demonstrated in physiological buffers), interfacial proteins are analyte receptors, determining sensor molecular recognition specificity. Receptors are bound to the FET through a polymeric interface, and gross disruption of interfaces that removes a large percentage of receptors or inactivates large fractions of them diminishes sensor sensitivity. Sensitivity is also determined by the distance between the bound analyte and the semiconductor. Consequently, differential properties of surface polymers are design parameters for FET sensors. We compare thickness, surface roughness, adhesion, friction and wear properties of silane polymer layers bound to oxides (SiO₂ and Al₂O₃, as on AlGaN HFETs). We compare those properties of the film–substrate pairs after an additional deposition of biotin and streptavidin. Adhesion between protein and device and interfacial friction properties affect FET reliability because these parameters affect wear resistance of interfaces to abrasive insult in vivo. Adhesion/friction determines the extent of stickage between the interface and tissue and interfacial resistance to mechanical damage. We document systematic, consistent differences in thickness and wear resistance of silane films that can be correlated with film chemistry and deposition procedures, providing guidance for rational interfacial design for planar AlGaN HFET sensors.     

Laser diffraction particle sizing by wet dispersion method for spray-dried infant formula

A laser diffraction particle sizing method involving wet analysis could be adapted effectively to measure the accurate particle size distribution of a spray-dried infant formula. Polar, polar aprotic and non-polar solvents, such as ethanol, methanol, acetone, pentane, heptane and hexane, were tested as dispersants for wet analysis. Non-polar solvents such as pentane, heptane and hexane found to be suitable dispersant because the shape of the infant formula particles in non-polar solvents was similar before and after the measurement while the particles had dissolved in the other solvents. The particle size distributions (PSD) of the infant formula determined by laser diffraction (Malvern Master Sizer, UK) using the dry analysis method with air was unsuitable because some parts of the primary and aggregated infant formula particles had been destroyed. The PSD graph of the air dispersion was shifted toward a smaller particle size from that of hexane dispersion. Overall, it is believed that laser diffraction particle sizing involving wet analysis with non-polar solvents may provide a suitable particle sizing method for infant formula products that is better than an air dispersion method.