Chip-based multimodal super-resolution microscopy for histological investigations of cryopreserved tissue sections

Histology involves the observation of structural features in tissues using a microscope. While diffraction-limited optical microscopes are commonly used in hist...     

Carriers-mediated ferromagnetic enhancement in Al-doped ZnMnO dilute magnetic semiconductors

Nano-crystalline Zn_{0.95 – x}Mn_0.05Al_xO (x = 0, 0.05, 0.10) dilute magnetic semiconductors (DMS) were synthesized by sol–gel derived auto-combustion. X-ray diffraction (XRD) analysis shows that the samples have pure wurtzite structure typical of ZnO without the formation of secondary phases or impurity. Crystallite sizes were approximated by Scherrer formula while surface morphology and grain sizes were measured by field emission scanning electron microscopy. Incorporation of Mn and Al into the ZnO structure was confirmed by energy-dispersive X-ray analysis. Temperature dependent electrical resistivity measurements showed a decreasing trend with the doping of Al in ZnMnO, which is attributable to the enhancement of free carriers. Vibrating sample magnetometer studies confirmed the presence of ferromagnetic behavior at room temperature. The results indicate that Al doping results in significant variation in the concentration of free carriers and correspondingly the carrier-mediated magnetization and room temperature ferromagnetic behavior, showing promise for practical applications. We attribute the enhanced saturation magnetization and electrical conductivity to the exchange interaction mediated by free electrons.     

Modelling the properties of pigment‐printed polypropylene nonwoven fabric using the Box–Behnken technique

The aim of this study was to develop statistical models for the effect of binder concentration and curing temperature and time on the air permeability, tear strength, tensile strength, and crocking fastness of pigment‐printed nonwoven polypropylene fabric. The design and analysis of the experimental work were carried out using Minitab ^® statistical software according to the Box–Behnken design of response surface methodology. Models were successfully developed. It was found that binder concentration improves the wet crocking and tensile strength while having a negative impact on all other responses. Increase in curing temperature and time affects the fabric tear strength negatively but has a positive effect on wet crocking fastness and fabric tensile strength. It could be concluded that pigment prints of good dry crocking fastness may be obtained on polypropylene nonwovens without deterioration in the mechanical strength and air permeability to a commercially unacceptable level. However, further work is required to improve the wet crocking fastness properties.     

A New Soft‐Fusion Approach for Multiple‐Receiver Wireless Communication Systems

In this paper, a new soft‐fusion approach for multiple‐receiver wireless communication systems is proposed. In the proposed approach, each individual receiver provides the central receiver with a confidence level rather than a binary decision. The confidence levels associated with the local receiver are modeled by means of soft‐membership functions. The proposed approach can be applied to wireless digital communication systems, such as amplitude shift keying, frequency shift keying, phase shift keying, multi‐carrier code division multiple access, and multiple inputs multiple outputs sensor networks. The performance of the proposed approach is evaluated and compared to the performance of the optimal diversity, majority voting, optimal partial decision, and selection diversity in case of binary noncoherent frequency shift keying on a Rayleigh faded additive white Gaussian noise channel. It is shown that the proposed approach achieves considerable performance improvement over optimal partial decision, majority voting, and selection diversity. It is also shown that the proposed approach achieves a performance comparable to the optimal diversity scheme.     

Subluminal and superluminal light propagation via electromagnetically induced transparency in radiatively and inhomogeneously broadened media

Contrary to popular belief, we demonstrate the feasibility of generating superluminal (and subluminal) probe (and signal) light via electromagnetically induced transparency in a medium comprising coupled double-ladder systems. This scheme can be realized in both homogeneously (radiative) as well as in inhomogeneously (Doppler) broadened atomic systems. Unlike more intricate earlier schemes, our scheme is based simply on steady-state propagation dynamics resulting from compensation of the inevitable absorption losses by large nonlinear gain generated through appropriate choice of the pump and coupling fields. We show how easily in this scheme the speed of weak probe (and signal) fields can be switched from subluminal to superluminal by simply varying the strengths of the coherent pump and coupling fields. Furthermore, it is shown that under these conditions both the signal and probe fields are intensity matched and both propagate with the same subluminal (or superluminal) group velocity without suffering loss or gain for long distance in the medium.     

Structural,Electrical, and Magnetic Properties of Ferrite–Polymer Composites

Six samples consisting of polypyrrole (PPy), pure NiFe₂O₄ ferrite, and their composites at ratio of 1:4 (PF1), 1:2 (PF2), 3:4 (PF3), and 1:1 (PF4) have been prepared by a coprecipitation method and their structural, electrical, dielectric, and magnetic properties measured experimentally. The direct-current (DC) resistivity was enhanced with increasing ferrite content, while the dielectric constant and loss decreased. The magnetic properties of all the composites and the ferrite revealed a narrow loop, confirming their soft nature. The saturation magnetization, remanence, and coercivity values increased with increasing ferrite content. The obtained parameter values suggest that such materials might be suitable for use in high-frequency applications.     

Unsupervised discrimination between lodged and non-lodged winter wheat: a case study using a low-cost unmanned aerial vehicle

Wheat lodging significantly reduce the grain yield and quality. Mapping wheat lodging timely and accurately can help farmers get full compensatory damages in time. Therefore, the objective of this study was to employ a low-cost unmanned aerial vehicle (UAV) carrying a Red-Green-Blue camera to discriminate lodged from non-lodged wheat effectively. Low-cost UAV is easier to be accepted by Chinese farmers most of whom manage small-scale farms. After comparing a variety of colour features as well as their texture features, this study found that the texture feature of mean of G/B (digital number ratio of the green band to the blue band) derived from occurrence measures was the optimum discriminator of lodged and non-lodged wheat. This discriminator was still effective although the spatial spectral variations in the study area were much more complex than that in previous studies. With an unsupervised method based on the discriminator, the UAV system was able to discriminate lodged wheat from non-lodged wheat. The resultant of overall accuracy was 89.55% and Kappa coefficient was 0.76. The producer’s accuracies were 81.23% and 93.62%, whereas the user’s accuracies were 86.15% and 91.08% for lodged and non-lodged wheat, respectively. The retrieved wheat lodging distribution map showed a substantial agreement with ground reference data.     

Applications of three-dimensional finite-difference seismic modeling in oil field exploitation and simulation

Two-dimensional finite-difference seismic models are excited by a line-source which leads to incorrect amplitudes. Moreover, in a structurally complex environment with strong three-dimensional (3-D) features, the results obtained from such models are often incorrect and do not include any out-of-plane events. On the other hand, 3-D models based on the ray-theory approximation fail to provide vital information such as diffractions and interference patterns which can strongly influence the seismic expression associated with hydrocarbon reservoirs. We present the results of a study in which an approximate version of mapped surfaces was used to carry out a synthetic 3-D finite-difference survey. This followed the necessary adjustment of various horizons and it involved the calibration of synthetic sections by comparing them with the corresponding unmigrated real-data sections. The simulation of reservoir characteristics was accomplished in reference to two key seismic horizons used in the model.     

Solar sterilization of water

According to a WHO report 80% of the diseases in developing countries are due to water related bacteria. Drinking boiled water is one of the solutions to this problem. Fuel wood is scarce but solar energy is plentiful in these countries and may be used to kill bacteria in drinking water. A simple and inexpensive solar device is shown to be effective in elimination of bacteria from water supplying sterilized water for family requirements. It is also shown that water need not be boiled but heated to 65°C only to make it bacteria free.