Optical Nanoscale Pool‐on‐Surface Design for Control Sensing Recognition of Multiple Cations

General design of optical chemical nanosensors is needed to develop efficient sensing systems with high flexibility, and low capital cost for control recognition of toxic analytes. Here, we designed optical chemical nanosensors for simple, high‐speed detection of multiple toxic metal ions. The systematic design of the nanosensors was based on densely patterned chromophores with intrinsic mobility, namely, “building‐blocks” onto three‐dimensional (3D) nanoscale structures. The ability to precisely modify the nanoscale pore surfaces by using a broad range of chromophores that have different molecular sizes and characteristics enables detection of multiple toxic ions. A key feature of this building‐blocks design strategy is that the surface functionality and good adsorption characteristics of the fabricated nanosensor arrays enabled the development of “pool‐on‐surface” sensing systems in which high flux of the metal analytes across the probe molecules was achieved without significant kinetic hindrance. Such a sensing design enabled sensitive recognition of metal ions up to sub‐picomolar detection limits (～10^?11 mol dm^?3), for first time, with rapid response time within few seconds. Moreover, because these sensing pools exhibited long‐term stability, reversibility and selectivity in detecting most pollutant cations, for example, Cr(VI), Pb(II), Co(II), and Pd(II) ions, they are practical and inexpensive. The key result in our study is that the pool‐on‐surface design for optical nanosensors exhibited significant ion‐selective ability of these target ions from environmental samples and waste disposals.     

Nanoscale Membrane Strips for Benign Sensing of HgII Ions: A Route to Commercial Waste Treatments

The integration of actively‐functional receptors into nanoscale networks outperformed competent detection devices and other ion‐sensing designs. Synthesis of azo chromophores with long hydrophobic tails showed an ecofriendly sensing and an extreme selectivity for divalent mercury analytes. In order to tailor the tip to Hg^II ion‐sensing functionality, we manipulated the chromophores into nanoscale membrane discs, which led to small, easy‐to‐use optical sensor strips. The design of these hydrophobic probes into ordered pore‐based membranes transformed the ion‐sensing systems into smart, stable assemblies and portable laboratory assays. The nanosensor membrane strips with chemical and mechanical stability allowed for reversible, stable and reusable detectors without any structural damage, even under rigorous chemical treatment for several numbers of repeated cycles. The optical membrane strips provided Hg^II ion‐sensing recognition for both cost‐ and energy‐saving systems. Indeed, the synthetic strips proved to have an efficient ability for various analytical applications, targeting especially for on‐site and in situ chemical analyses, and for continuous monitoring of toxic Hg^II ions. On the proximity‐sensing front, these miniaturized nanomembrane strips can revolutionize the consumer and industrial market with the introduction of the probe surface‐mount naked‐eye ion‐sensor strips.     

Concentrator multijunction solar cell characteristics under variable intensity and temperature

The performance of multijunction solar cells has been measured over a range of temperatures and illumination intensities. Temperature coefficients have been extracted for three‐junction cell designs that are in production and under development. A simple diode model is applied to the three‐junction performance as a means to predict performance under operating conditions outside the test range. These data may be useful in guiding the future optimization of concentrator solar cells and systems. Copyright © 2008 John Wiley & Sons, Ltd.     

An apparatus for the study of wear under dynamic loading conditions

A multipurpose wear testing apparatus has been designed, constructed and calibrated. The apparatus is primarily an impact wear testing device, but it may also be used for vibratory and oscillatory wear experimentation. The system utilizes a versatile displacement- and force-controlled device, which allows accurate control and measurement of the load cycles and their frequencies and the relative normal and transverse velocities between the wear surfaces as well as their time of contact. Features of this design permit testing at elevated frequencies and investigation of the effect of individual parameters on the wear process. These features include a facility to manipulate the system stiffness, the ability to control the impact and rotational velocities independently, feedback to maintain a constant nominal stress parameter, the ability to use spherical or cylindrical wear specimens and a method of applying the load and relative transverse motion in a constant, random or prescribed manner. The design facilitates modifications to include lubrication and environmental control, measurement of friction forces and fretting wear capabilities. Some initial results are included.     

Thiolated alginate-based multiple layer mucoadhesive films of metformin forintra-pocket local delivery: in vitro characterization and clinical assessment

Abstract

Introduction: Periodontal disease broadly defines group of conditions in which the supportive structure of the tooth (periodontium) is destroyed. Recent studies suggested that the anti-diabetic drug metformin hydrochloride (MF) has an osteogenic effect and is beneficial for the management of periodontitis.

Objective: Development of strong mucoadhesive multiple layer film loading small dose of MF for intra-pocket application.

Methodology: Multiple layer film was developed by double casting followed by compression method. Either 6% carboxy methyl cellulose sodium (CMC) or sodium alginate (ALG) constituted the inner drug (0.6%) loaded layer. Thiolated sodium alginate (TSA; 2 or 4%) constituted the outer drug free layers to enhance mucoadhesion and achieve controlled drug release. Optimized formulation was assessed clinically on 20 subjects.

Results: Films were uniform, thin and hard enough for easy insertion into periodontal pockets. Based on water uptake and in vitro drug release, CMC based film with 4% TSA as an outer layer was the optimized formulation with enhanced mucoadhesion and controlled drug release (83.73% over 12?h). SEM showed the effective fabrication of the triple layer film in which connective lines between the layers could be observed. FTIR examination suggests possibility of hydrogen bonding between the –NH groups of metformin and –OH groups of CMC. DSC revealed the presence of MF mainly in the amorphous form. Clinical results indicated improvement of all clinical parameters six months post treatment.

Conclusion: The results suggested that local application of the mucoadhesive multiple layer films loaded with metformin hydrochloride was able to manage moderate chronic periodontitis.     

Liquid-Metal Synthesized Ultrathin SnS Layers for High-Performance Broadband Photodetectors

Atomically thin materials face an ongoing challenge of scalability, hampering practical deployment despite their fascinating properties. Tin monosulfide (SnS), a low-cost, naturally abundant layered material with a tunable bandgap, displays properties of superior carrier mobility and large absorption coefficient at atomic thicknesses, making it attractive for electronics and optoelectronics. However, the lack of successful synthesis techniques to prepare large-area and stoichiometric atomically thin SnS layers (mainly due to the strong interlayer interactions) has prevented exploration of these properties for versatile applications. Here, SnS layers are printed with thicknesses varying from a single unit cell (0.8 nm) to multiple stacked unit cells (≈1.8 nm) synthesized from metallic liquid tin, with lateral dimensions on the millimeter scale. It is reveal that these large-area SnS layers exhibit a broadband spectral response ranging from deep-ultraviolet (UV) to near-infrared (NIR) wavelengths (i.e., 280–850 nm) with fast photodetection capabilities. For single-unit-cell-thick layered SnS, the photodetectors show upto three orders of magnitude higher responsivity (927 A W⁻¹) than commercial photodetectors at a room-temperature operating wavelength of 660 nm. This study opens a new pathway to synthesize reproduceable nanosheets of large lateral sizes for broadband, high-performance photodetectors. It also provides important technological implications for scalable applications in integrated optoelectronic circuits, sensing, and biomedical imaging.     

Novel Analytical Thermal Performance Rate Analysis in ZnO-SAE50 Nanolubricant: Nonlinear Mathematical Model

The investigation of local thermal transport rate in the nanolubricants is significant. These lubricants are broadly used in environmental pollution, mechanical engineering and in the paint industry due to high thermal performance rate. Therefore, thermal transport in ZnO-SAE50 nanolubricant under the impacts of heat generation/absorption is conducted. The colloidal suspension is flowing between parallel stretching disks in which the lower disk is positioned at z = 0 and upper disk apart from distance d. The problem is transformed in dimensionless version via described similarity transforms. In the next stage, an analytical technique (VPM) is implemented for the solution purpose. The graphical results against multiple flow parameters were furnished over the region of interest and explained comprehensively. It is imperative to mention that the results are plotted for ZnO-SAE50 and conventional liquid as well. Further, rapid motion of the fluid is perceived against high Reynolds and γ parameters. The wall shear stresses at the upper end rises for multiple Reynolds and γ while; decrement is detected at the lower end. The significant contribution of an internal heat source is noted for thermal performance rate at the upper end. Foremost, the local heat transport rate declines at the lower disk. By altering Reynolds number, prompt heat transfer rate is gained at the upper disk and increasing behavior of the local heat transport rate is slow at the lower disk. From the study, it is concluded that the nanolubricants have high thermal characteristics. Therefore, such fluids are reliable to use in above stated areas.     

Dual Branches of MHD Three-Dimensional Rotating Flow of Hybrid Nanofluid on Nonlinear Shrinking Sheet

In this study, magnetohydrodynamic (MHD) three-dimensional (3D) flow of alumina (Al₂O₃) and copper (Cu) nanoparticles of an electrically conducting incompressible fluid in a rotating frame has been investigated. The shrinking surface generates the flow that also has been examined. The single-phase (i.e., Tiwari and Das) model is implemented for the hybrid nanofluid transport phenomena. Results for alumina and copper nanomaterials in the water base fluid are achieved. Boundary layer approximations are used to reduce governing partial differential (PDEs) system into the system of the ordinary differential equations (ODEs). The three-stage Lobatto IIIa method in bvp4c solver is applied for solutions of the governing model. Graphical results have been shown to examine how velocity and temperature fields are influenced by various applied parameters. It has been found that there are two branches for certain values of the suction/injection parameter b: The rise in copper volumetric concentration improved the velocity of hybrid nanofluid in the upper branch. The heat transfer rate improved for the case of hybrid nanofluid as compared to the viscous fluid and simple nanofluid.     

Robust and High Accuracy Algorithm for Detection of Pupil Images

Recently, many researchers have tried to develop a robust, fast, and accurate algorithm. This algorithm is for eye-tracking and detecting pupil position in many applications such as head-mounted eye tracking, gaze-based human-computer interaction, medical applications (such as deaf and diabetes patients), and attention analysis. Many real-world conditions challenge the eye appearance, such as illumination, reflections, and occasions. On the other hand, individual differences in eye physiology and other sources of noise, such as contact lenses or make-up. The present work introduces a robust pupil detection algorithm with and higher accuracy than the previous attempts for real-time analytics applications. The proposed circular hough transform with morphing canny edge detection for Pupillometery (CHMCEP) algorithm can detect even the blurred or noisy images by using different filtering methods in the pre-processing or start phase to remove the blur and noise and finally the second filtering process before the circular Hough transform for the center fitting to make sure better accuracy. The performance of the proposed CHMCEP algorithm was tested against recent pupil detection methods. Simulations and results show that the proposed CHMCEP algorithm achieved detection rates of 87.11, 78.54, 58, and 78 according to Świrski, ExCuSe, Else, and labeled pupils in the wild (LPW) data sets, respectively. These results show that the proposed approach performs better than the other pupil detection methods by a large margin by providing exact and robust pupil positions on challenging ordinary eye pictures.