Experimental Investigation on Capillary Water Absorption in Discrete Planar Cracks

Water movement is responsible for the deterioration of concrete and concrete structures, especially when distributed microcracks exist because cracks can facilitate the ingress of aggressive agents. Experiment was carried out on capillary water absorption by discrete planar cracks to clarify the effect of crack width on the transport speed of water by crack. The granite samples were used to create parallel and smooth cracks with purpose to avoid rehydration of the cement-based materials. Two granite blocks were applied to joint by glue for artificially fabricating a single parallel crack by means of ultra thin steel disc with various thicknesses of 50, 100, 150 and 200 mm. The capillary absorption test was conducted on the specimens according to the gravimetric method recommended in ASTM C1585. Mass of absorbed water by the single discrete crack was measured. It was found that the cumulative water mass of specimen generally increases with an increase of crack width for the ranges studied. The cumulative water mass rapidly increases for the initial stages of water absorption test while at later stages the rate of absorbed water is slowed down apparently

Harp Blood Pressure Monitor

The blood pressure monitoring market is currently dominated by cuff-based blood pressure monitors which have numerous shortcomings. The current products are not only bulky and restrictive but they also inflate the cuffs to an uncomfortable degree while in use. This leads to the second major drawback, which is the inability to provide the user with continuous readings of their blood pressure.  Our product aims to cover those shortcomings and provide users with a more seamless blood pressure measurement experience that does not hinder their daily lives while providing accurate and continuous measurements of their blood pressure to give them better insight into their health condition. The device will be wearable and will be composed of two main subsystems: The first part is a wearable hardware subsystem which will contain the required sensors, a microcontroller, and a bluetooth module to communicate with the second subsystem. And the second main part is a software subsystem in the form of a mobile app that will receive the data from the wearable device, analyze it, and display the results to the use

An Overview of Micro(Nano)Plastics in the Environment: Sampling, Identification, Risk Assessment and Control

Advances in urban infrastructure, a flourishing polymer sector, and more traffic have all contributed to a rise in micro(nano)plastics in the environment. Researchers are exploring the production, fate, toxicity threshold, and severity of micro(nano)plastic exposure. Albeit, understanding sampling protocols, preservation of samples, and characterization of micro(nano)plastics obtained from the different mediums (e.g., soil, water, air, and living bodies) is still challenging. Particularly identification of micro(nano)plastics, on the other hand, is restricted and limited to the typical generic definition of contaminating sources. In addition, before micro(nano)plastics degrade naturally, many challenges must be overcome, enhancing the need for research on assisted degradation. Thus, a systematic review is presented, which begins by discussing micro(nano)plastic identification, sampling, and handling; then showcases the environmental and health consequences and how to control them; finally, it discusses environmental micro(nano)plastics management options. According to studies, biological and chemical methods to break down micro(nano)plastics have risen in popularity. However, these methods often only cover one type of plastic. Furthermore, these solutions can transform polymers into micro(nano)plastics and may also produce byproducts, increasing environmental contamination risk. Therefore, control, prevention, and management strategies are all investigated to generate more realistic and long-term solutions. The literature suggests a combination of different microorganisms (e.g., different bacterial species) and different approaches (e.g., filtration with degradation) could be more effective in the treatment of micro(nano)plastics. Furthermore, according to the literature, relevant health risks associated with micro(nano)plastics to humans from various exposure routes are currently unclear. Likewise, standardization of methods supported with sophisticated state-of-the-art apparatus for detecting micro(nano)plastics is required. Overall, precision in micro(nano)plastic identification and treatment strategy selection is critical, and their usage should be regulated if their environmental behavior is not properly addressed

Construct Polyoxometalate Frameworks through Covalent Bonds

An emerging strategy for exploring the application of polyoxometalates (POMs) is to assemble POM clusters into open-framework materials, especially inorganic–organic hybrid three-dimensional (3D) open-framework materials, via the introduction of different organic linkers between the POM clusters. This strategy has yielded a few 3D crystalline POMs of which a typical class is the group of polyoxometalate metal–organic frameworks (POMMOFs). However, for reported POMMOFs, only coordination bonds are involved between the linkers and POM clusters, and it has not yet produced any covalently bonded polyoxometalate frameworks. Here, the concept of “covalently bonded POMs (CPOMs)” is developed. By using vanadoborates as an example, we showed that the 3D CPOMs can be obtained by a condensation reaction through the oxolation mechanism of polymer chemistry. In particular, suitable single crystals were harvested and characterized by single-crystal X-ray diffraction. This work forges a link among polymer science, POM chemistry, and open-framework materials by demonstrating that it is possible to use covalent bonds according to polymer chemistry principles to construct crystalline 3D open-framework POM materials

The β-Lactamase Gene Profile and a Plasmid-Carrying Multiple Heavy Metal Resistance Genes of Enterobacter cloacae

In this work, by high-throughput sequencing, antibiotic resistance genes, including class A (blaCTX-M, blaZ, blaTEM, blaVEB, blaKLUC, and blaSFO), class C (blaSHV, blaDHA, blaMIR, blaAZECL-29, and blaACT), and class D (blaOXA) β-lactamase genes, were identified among the pooled genomic DNA from 212 clinical Enterobacter cloacae isolates. Six blaMIR-positive E. cloacae strains were identified, and pulsed-field gel electrophoresis (PFGE) showed that these strains were not clonally related. The complete genome of the blaMIR-positive strain (Y546) consisted of both a chromosome (4.78 Mb) and a large plasmid pY546 (208.74 kb). The extended-spectrum β-lactamases (ESBLs) (blaSHV-12 and blaCTX-M-9a) and AmpC (blaMIR) were encoded on the chromosome, and the pY546 plasmid contained several clusters of genes conferring resistance to metals, such as copper (pco), arsenic (ars), tellurite (ter), and tetrathionate (ttr), and genes encoding many divalent cation transporter proteins. The comparative genomic analyses of the whole plasmid sequence and of the heavy metal resistance gene-encoding regions revealed that the plasmid sequences of Klebsiella pneumoniae (such as pKPN-332, pKPN-3967, and pKPN-262) shared the highest similarity with those of pY546. It may be concluded that a variety of β-lactamase genes present in E. cloacae which confer resistance to β-lactam antibiotics and the emergence of plasmids carrying heavy metal resistance genes in clinical isolates are alarming and need further surveillance