Study on a terahertz biosensor based on graphene-metamaterial

The interaction between the terahertz wave propagating in free space and the sample is weak, which leads to the weak signal of the sample, which cannot meet the detection needs of trace samples. In order to meet the detection of trace samples, a kind of metamaterial absorber (the basic unit of the absorber is composed of gold-high resistance silicon-aluminum three-layer structure) is designed, and the monolayer graphene is transferred on the surface of the metamaterial absorber to construct the graphene-metamaterial absorber heterostructure. The transmission spectrum of the resonant cavity is simulated and measured by terahertz time domain spectroscopy system, and the obvious resonance frequency shift is observed. The results show that the graphene-metamaterial absorber heterostructure can detect josamycin antibiotic solution with concentration of 0.02 mg/L (the mass of josamycin is 0.2 ng). Compared with using the same structure metamaterial absorber to detect josamycin antibiotics, the sensitivity is increased by an order of magnitude. Using graphene-metamaterial heterostructure to detect the relative change of heterostructure reflectivity caused by josamycin antibiotics can reach 40%. The research in this paper provides a new technical means for accurate and rapid detection in terahertz band.

Comprehensive feasibility study for application of waste tire chips in enhancing the performance of shallow foundations

This study aims to assess the viability of waste tire chips as sand reinforcement for enhancing the performance of shallow foundations. Detailed experimental investigation is carried out to analyze the behavior of model footing placed on sand reinforced with waste tire chips, and the observed improvement is quantified in terms of a non-dimensional factor, bearing capacity ratio (BCR). The influence of variation of several factors such as the content of tire-chip reinforcement, the extent of tire reinforced sand zone, footing shape, the effect of submergence, and scale effects on BCR has also been studied. Test results indicate significant improvement in BCR validating the effectiveness of tire chips in improving the bearing capacity of sand. The optimum tire content, depth of reinforced zone, and width of the reinforced zone are recommended as 30%, 1B-2B, and 3B-5B, respectively (B is the width of the footing), where BCR increased to more than 5 under both low strain and high strain conditions. It was also established that submergence of the reinforced soil and shape and size of footing did not have a significant influence on the BCR. Moreover, the performance of tire chip-reinforced sand is found to be better than both fiber- and geogrid-reinforced sand. Bearing capacity increase of up to 1.89 times and 2.40 times was observed in tire chip-reinforced sand in comparison to fiber- and geogrid-reinforced sand, respectively. On the whole, the significant improvement in BCR and the better performance of tire chips over other alternatives ascertain that bulk utilization of tire wastes in shallow foundations has immense potential for effective waste management of large stockpiles of tires and can prove to be an economical and sustainable solution for the construction industry.

Comparative analysis of regulating characteristics between air-ring flow regulating valve and center butterfly valve

In this study, a novel air-ring flow regulating valve was proposed to reduce the flow resistance caused by valve structural pressure drop in fluid transportation pipeline system. The regulating characteristics at different valve openings were analyzed by numerical method and the results were compared with the center butterfly valve which is most widely applied in fluid transportation pipeline system. Besides, an experimental system was designed to validate the numerical model in the present study. The results indicated that the simulation results agree well with experimental data. The resistance coefficient of the air-ring flow regulating valve is smaller than that of the center butterfly valve when the valve opening is greater than 67%, and the resistance coefficient is reduced by up to 100% as the valve is fully opened. Both valves maintain approximately equal percentage flow characteristics, the deviation in relative flow coefficient is small. In addition, the wall shear stress of the air-ring flow regulating valve is much smaller than that of the center butterfly valve at the same valve opening, and the maximum velocity in the pipeline system is always smaller than that of the center butterfly valve, which significantly reduces valve surface abrasive erosion and thus prolongs its service life.

Changes in concentrations and characteristics of asbestos fibers dispersed from corrugated asbestos cement sheets due to stabilizer treatment

Asbestos management in Korea has, to date, focused exclusively on dismantlement and removal; however, the effective management of asbestos in public facilities and rural dwellings is also critical. This study compares eight different asbestos stabilization treatments and their effectiveness in reducing asbestos fiber dispersion from weathered corrugated asbestos cement sheets (CACS) under different wind conditions. The effectiveness of the different asbestos stabilizers was assessed in order to identify the characteristics of fibers dispersed from treated CACS samples. The impact of wind speed on the concentration and composition of the dispersed fibers was also evaluated. For all wind speeds, the concentration of the fibers dispersed from the CACS samples that were treated with stabilizers decreased relative to the untreated CACS. These results show that asbestos concentrations were considerably reduced following stabilizer treatment and that treated CACS dispersed fewer asbestos fibers relative to untreated CACS. The results of this study will be useful for the development of strategies regarding the appropriate management of asbestos in public buildings.

Impact of manufacturing technology and material composition on the surface characteristics of hydrogel contact lenses

BACKGROUND

Our aim was to investigate the impact of manufacturing method and material composition on the surface characteristics of hydrogel contact lenses.

METHODS

Five lens types were examined; three polyhydroxyethyl methacrylate (pHEMA) lenses, each manufactured by a different technique, namely, lathing, spin-casting and cast-moulding, a HEMA/methacrylic acid cast-moulded lens and a HEMA/glycerol methacrylate cast-moulded lens. Six lenses of each type were examined (front and back) using scanning electron microscopy (SEM). Additionally, both surfaces of three lenses from each of the pHEMA lens groups were examined, partially hydrated, using an atomic force microscope (AFM). Qualitative data were gathered for both SEM and AFM studies in addition to root-mean-square (RMS) roughness values for the lenses investigated with AFM.

RESULTS

The surfaces of the lathed lenses were covered in lathing/polishing marks. RMS roughness values for the anterior surface (10.9 +/- 4.3 nm) were significantly greater (p = 0.02) than those of the posterior surface (9.3 +/- 0.8 nm). The two surfaces of the spun-cast lens appeared similar by SEM but AFM RMS roughness values were greater (p = 0.02) for the anterior (12.3 +/- 1.8 nm) than the posterior (5.8 +/- 1.9 nm) surface. Both SEM and AFM showed similar topographic appearances for the surfaces of the cast-moulded pHEMA lens, although RMS roughness values were greater (p = 0.02) for the anterior (5.8 +/- 0.9 nm) than the posterior (3.9 +/- 0.3 nm) surface. All three cast-moulded lenses had more processing debris than the lathed and spun-cast pHEMA lenses. Overall, the surfaces of the lathed lens were 'rougher' than those of the cast-moulded lens (p = 0.01).

CONCLUSION

The surface topographies of the hydrogel contact lenses are dependent on the method of manufacture. Cast-moulded lenses are associated with apparently 'stickier' surfaces, which may be indicative of surface degradation during the manufacturing process.

In Vitro Testing and Comparison of Additively Manufactured Polymer Impellers for the CentriMag Blood Pump

Additive manufacturing (AM) is an effective tool for accelerating knowledge gain in development processes, as it enables the production of complex prototypes at low cost and with short lead times. In the development of mechanical circulatory support, the use of cheap polymer-based AM techniques for prototype manufacturing allows more design variations to be tested, promoting a better understanding of the respective system and its optimization parameters. Here, we compare four commonly used AM processes for polymers with respect to manufacturing accuracy, surface roughness, and shape fidelity in an aqueous environment. Impeller replicas of the CentriMag blood pump were manufactured with each process and integrated into original pump housings. The assemblies were tested for hydraulic properties and hemolysis in reference to the commercially available pump. Computational fluid dynamic simulations were carried out to support the transfer of the results to other applications. In hydraulic testing, the deviation in pressure head and motor current of all additively manufactured replicas from the reference pump remained below 2% over the entire operating range of the pump. In contrast, significant deviations of up to 620% were observed in hemolysis testing. Only the replicas produced by stereolithography showed a nonsignificant deviation from the reference pump, which we attribute to the low surface roughness of parts manufactured thereby. The results suggest that there is a flow-dependent threshold of roughness above which a surface strongly contributes to cell lysis by promoting a hydraulically rough boundary flow.

Additive Manufacturing Using Melt Extruded Thermoplastics for Tissue Engineering

Melt extrusion of thermoplastic materials is an important technique for fabricating tissue engineering scaffolds by additive manufacturing methods. Scaffold manufacturing is commonly achieved by one of the following extrusion-based techniques: fused deposition modelling (FDM), 3D-fiber deposition (3DF), and bioextrusion. FDM needs the input material to be strictly in the form of a filament, whereas 3DF and bioextrusion can be used to process input material in several forms, such as pellets or powder. This chapter outlines a common workflow for all these methods, going from the material to a scaffold, while highlighting the special requirements of particular methods. A few ways of characterizing the scaffolds are also briefly described.

Silk fibroin and silk-based biomaterial derivatives for ideal wound dressings

Silk fibroin (SF) is derived from Bombyx mori silkworm cocoons and has been used in textiles and as a suture material for decades. More recently, SF has been used for various new biomedical applications, including as a wound dressing, owing to its excellent biological and mechanical properties. Specifically, the mechanical stiffness, versatility, biocompatibility, biodegradability, water vapour permeability and slight bactericidal properties make SF an excellent candidate biomaterial for wound dressing applications. The effectiveness of SF as a wound dressing has been tested and well-documented in vitro as well as in-vivo, as described here. Dressings based on SF are currently used for treating a wide variety of chronic and acute (e.g. burn) wounds. SF and its derivatives prepared as biomaterials are available as sponges, hydrogels, nanofibrous matrices, scaffolds, micro/nanoparticles, and films. The present review discusses the potential role of SF in wound dressing and its modulation for wound dressing applications. The comparison of SF based dressings with other natural polymers understands the readers, the scope and limitation of the subject in-depth.

The effectiveness of ergonomic interventions in material handling operations

This study evaluated the effectiveness of ergonomic interventions in material handling operations involving 33 employers and 535 employees from 2012 to 2017. Outcomes included employee-reported low back/upper extremity pain and safety incidents at baseline, every three months, and annually for up to two years. A total of 32.5% of employees completed at least one survey, while 13.6% completed all nine surveys over two years. Among highly exposed employees (who reported handling >= 50 lbs. > 33% of the time), upper extremity pain frequency and severity were lower among those who reported using the intervention routinely versus those that reported using their body strength alone to handle objects >= 50 lbs. After excluding from analyses one employer that used anti-fatigue mats, low back pain frequency was also significantly lower among highly exposed intervention users. In conclusion, there was some evidence that the interventions were effective in reducing employee-reported pain for highly exposed employees.

Detecting cognitive hacking in visual inspection with physiological measurements

Cyber threats are targeting vulnerabilities of human workers performing tasks in manufacturing processes, including visual inspection to bias their decision-making, thereby sabotaging product quality. This article examines the use of priming as a form of "cognitive hacking" to adversely affect quality inspection decisions in manufacturing, and investigates physiological measurements as means to detect such intrusion. In a within-subject design experiment, twenty participants inspected surface roughness of a manufactured component with and without exposure to priming on the display of an inspection logging system. The results show that the presence of primes impacted accuracy on surface roughness, cortical activities at parietal lobe P4, and eye gaze for inspecting components. The experiment provides supporting evidence that basic hacking of a worker display can be an effective method to alter decision making in inspection. The findings also illustrate that cortical activities and eye gaze can be useful indicators of cognitive hacking. A major implication of the study results is that physiological indicators can be effective at revealing unconscious cognitive influence in visual inspection.

Applicability of lignin polymers for automobile brake pads as binder and filler materials and their performance characteristics

We present environmentally friendly brake pads produced with three different types of lignin, soda lignin (SL), sulphuric acid lignin (SAL) and heat-treated SAL (HL), as frictional materials to replace phenol formaldehyde resin (PFR, binder) and cashew nut shell liquid (CNSL, filler) in commercial automobile brake pad. Then the performance characteristics of the lignin-added brake pads were tested and compared using several fundamental tests. The results showed that lignin-added brake pads adhered to the SAE standard (0.25) for friction coefficient, which is the primary contributor to the performance of a braking system. In particular, the replacement of PFR with SL demonstrated a better friction coefficient than did replacement with SAL or HL, reaching up to 0.6. On the other hand, when lignin was substituted for CNSL as filler, HL-added brake pads showed a significant improvement in wear resistance of 0.12 g (dust generation) compared to SL and SAL, which had a resistance of approximately 0.25 g.

A perceptual bias for man-made objects in humans

Ambiguous images are widely recognized as a valuable tool for probing human perception. Perceptual biases that arise when people make judgements about ambiguous images reveal their expectations about the environment. While perceptual biases in early visual processing have been well established, their existence in higher-level vision has been explored only for faces, which may be processed differently from other objects. Here we developed a new, highly versatile method of creating ambiguous hybrid images comprising two component objects belonging to distinct categories. We used these hybrids to measure perceptual biases in object classification and found that images of man-made (manufactured) objects dominated those of naturally occurring (non-man-made) ones in hybrids. This dominance generalized to a broad range of object categories, persisted when the horizontal and vertical elements that dominate man-made objects were removed and increased with the real-world size of the manufactured object. Our findings show for the first time that people have perceptual biases to see man-made objects and suggest that extended exposure to manufactured environments in our urban-living participants has changed the way that they see the world.

Influence of design and postprocessing parameters on the degradation behavior and mechanical properties of additively manufactured magnesium scaffolds

Magnesium shows promising properties concerning its use in absorbable implant applications such as biodegradability, improved mechanical strength and plastic deformability. Following extensive research, the first fixation and compression screws composed of magnesium rare earth alloys were commercialised, notably in the field of orthopaedic surgery. Preclinical and clinical follow-up studies showed that the rapid degradation of unprotected metallic Magnesium surfaces and concomitant hydrogen gas bursts still raise concern regarding certain surgical indications and need to be further improved. In order to enlarge the scope of further applications, the development of future magnesium implants must aim at freedom of design and reduction of volume, hereby enabling higher functionalised implants, as e.g. plate systems or scaffold grafts for bone replacement therapy. In order to overcome the boundaries of conventional manufacturing methods such as turning or milling, the process of Laser Powder Bed Fusion (LPBF) for magnesium alloys was recently introduced. It enables the production of lattice structures, therefore allowing for reduction of implant material volume. Nevertheless, the concomitant increase of free surface of such magnesium scaffolds further stresses the aforementioned disadvantages of vast degradation and early loss of mechanical stability if not prevented by suitable postprocessing methods. Magnesium scaffold structures with different pore sizes were therefore manufactured by LPBF and consequently further modified either by thermal heat treatment or Plasma Electrolytic Oxidation (PEO). Implant performance was assessed by conducting degradation studies and mechanical testing. PEO modified scaffolds with small pore sizes exhibited improved long-term stability, while heat treated specimens showed impaired performance regarding degradation and mechanical stability. STATEMENT OF SIGNIFICANCE: Magnesium based scaffold structures offer wide possibilities for advanced functionalized bioabsorbable implants. By implementing lattice structures, big implant sizes and mechanically optimized implant geometries can be achieved enabling full bone replacement or large-scale plate systems, e.g. for orthopedic applications. As shape optimization and lattice structuring of such scaffolds consequently lead to enlarged surface, suitable design and postprocessing routines come into focus. The presented study addresses these new and relevant topics for the first time by evaluating geometry as well as heat and surface treatment options as input parameters for improved chemical and mechanical stability. The outcome of these variations is measured by degradation tests and mechanical analysis. Evaluating these methods, a significant contribution to the development of absorbable magnesium scaffolds is made. The findings can help to better understand the interdependence of high surface to volume ratio Magnesium implants and to deliver methods to incorporate such lattice structures into future large-scale implant applications manufactured from bioabsorbable Magnesium alloys.

Vibration of symmetrically layered angle-ply cylindrical shells filled with fluid

Vibrational behaviour of symmetric angle-ply layered circular cylindrical shell filled with quiescent fluid is presented. The equations of motion of cylindrical shell in terms of stress and moment resultants are derived from the first order shear deformation theory. Irrotational of inviscid fluid are expressed as the wave equation. These two equations are coupled. Strain-displacement relations and stress-strain relations are adopted into the equations of motion to obtain the differential equations with displacements and rotational functions. A system of ordinary differential equation is obtained in one variable by assuming the functions in separable form. Spline of order three is applied to approximate the displacement and rotational functions, together with boundary conditions, to get a generalised eigenvalue problem. The eigenvalue problem is solved for eigen frequency parameter and associate eigenvectors of spline coefficients. The study of frequency parameters are analysed using the parameters the thickness ratio, length ratio, angle-ply, properties of material and number of layers under different boundary conditions.

Performance of disposable endoscopic forceps according to the manufacturing techniques

BACKGROUND/AIMS

Recently, to lower the production costs and risk of infection, new disposable biopsy forceps made using simple manufacturing techniques have been introduced. However, the effects of the manufacturing techniques are unclear. The aim of this study was to evaluate which types of biopsy forceps could obtain good-quality specimens according to the manufacturing techniques.

METHODS

By using an in vitro nitrile glove popping model, we compared the popping ability among eight different disposable biopsy forceps (one pair of biopsy forceps with cups made by a cutting method [cutting forceps], four pairs of biopsy forceps with cups made by a pressing method [pressing forceps], and three pairs of biopsy forceps with cups made using a injection molding method [molding forceps]). Using an in vivo swine model, we compared the penetration depth and quality of specimen among the biopsy forceps.

RESULTS

In the in vitro model, the molding forceps provided a significantly higher popping rate than the other forceps (cutting forceps, 25.0%; pressing forceps, 17.5%; and molding forceps, 41.7%; p = 0.006). In the in vivo model, the cutting and pressing forceps did not provide larger specimens, deeper biopsy specimen, and higher specimen adequacy than those obtained using the molding forceps (p = 0.2631, p = 0.5875, and p = 0.2147, respectively). However, the molding forceps showed significantly more common crush artifact than the others (cutting forceps, 0%; pressing forceps, 5.0%; and molding forceps, 43.3%; p = 0.0007).

CONCLUSION

The molding forceps provided lower performance than the cutting and pressing forceps in terms of crush artifact.

Analysis of the Effect of Concentrations of Four Whitening Products in Cover Transmissivity of Mediterranean Greenhouses

The present work analyses the traditional method of applying whitening products on Mediterranean greenhouses. Four commercial whitening products (agricultural solar protectors, ASPs), applied at four doses, were compared with a non-whitened cover. The traditional product “Blanco de España” with 99% calcium carbonate (CaCO₃) and other three products with 97% CaCO₃ that incorporate adhesives were tested. The use of adhesives in ASP did not influence the effect of the different products on the inside temperature, and at the same dose all four products show a similar behaviour. The findings support the maximum dose recommended by other authors of 0.50 kg L⁻¹ (50/100), above which the transmissivity of the greenhouse cover decreases by over 50%. The effect of ASP on the transmissivity of the cover depends principally on the dose applied, but also on the climatic conditions (solar radiation, cloud cover, etc.) and on the time of year (solar elevation). The habitual use of a constant dose throughout the year does not seem to be the most adequate. Recommended doses should vary according to the time of year and the desired degree of transmissivity reduction. The adhesive components are shown to provide a high degree of protection against heavy rain. The study recommends a standardised method of ASP application, establishing a method that allows the grower to verify the concentration of the product that will remain on the greenhouse cover.

Design of Complexly Graded Structures inside Three-Dimensional Surface Models by Assigning Volumetric Structures

An innovative approach for designing complex structures from STL-datasets based on novel software for assigning volumetric data to surface models is reported. The software allows realizing unique complex structures using additive manufacturing technologies. Geometric data as obtained from imaging methods, computer-aided design, or reverse engineering that exist only in the form of surface data are converted into volumetric elements (voxels). Arbitrary machine data can be assigned to each voxel and thereby enable implementing different materials, material morphologies, colors, porosities, etc. within given geometries. The software features an easy-to-use graphical user interface and allows simple implementation of machine data libraries. To highlight the potential of the modular designed software, an extrusion-based process as well as a two-tier additive manufacturing approach for short fibers and binder process are combined to generate three-dimensional components with complex grading on the material and structural level from STL files.

Assessing the chronic respiratory health risk associated with inhalation exposure to powdered toner for printing in actual working conditions: a cohort study on occupationally exposed workers over 10 years

BACKGROUND

Little epidemiological evidence exists regarding the chronic respiratory effects of inhaled powdered toner exposure in humans, although several case reports have suggested the existence of lung disorders that might be related to exposure to toner dust.

OBJECTIVE

We aimed to estimate the chronic health risk to humans associated with routine toner dust exposure in copier industry workers under current actual work conditions.

DESIGN

A prospective observational cohort study of occupational population.

METHODS

Changes in chest radiogram, spirometry measurements and serum and urine biomarkers of biomedical responses to extrinsic stress, as well as subjective symptoms were longitudinally observed for up to 10 years in Japanese copier industry workers responsible for the manufacturing, maintenance or recycling of powdered toner or toner-using machines. A total of 694 subjects who did not change their work category during the follow-up and were free from chronic respiratory diseases at the baseline survey provided reliable results on at least three survey occasions during 3 years or more of follow-up.

RESULTS

Typical fibrosis findings associated with pneumoconiosis was not observed on chest radiograms. No significant differences associated with toner exposure were noted in the frequency of new incidence of either non-specific findings on chest radiogram or serum fibrosis biomarkers (sialylated carbohydrate antigen KL-6 and surfactant protein D). However, the exposed subjects tended to show increases in the frequency of respiratory symptoms and reduced spirometry results during the follow-up compared with the control group, although significant differences were only seen in chronic cough.

CONCLUSIONS

Under the current reasonably controlled work environmental conditions, lung fibrotic changes caused by inhaled dust exposure, including powdered toner, appear to be relatively uncommon; however, non-specific temporal irritation causing subjective symptoms and inflammatory responses might exist.

Tire wear particles in the aquatic environment - A review on generation, analysis, occurrence, fate and effects

Tire wear particles (TWP), generated from tire material during use on roads have gained increasing attention as part of organic particulate contaminants, such as microplastic, in aquatic environments. The available information on properties and generation of TWP, analytical techniques to determine TWP, emissions, occurrence and behavior and ecotoxicological effects of TWP are reviewed with a focus on surface water as a potential receptor. TWP emissions are traffic related and contribute 5-30% to non-exhaust emissions from traffic. The mass of TWP generated is estimated at 1,327,000 t/a for the European Union, 1,120,000 t/a for the United States and 133,000 t/a for Germany. For Germany, this is equivalent to four times the amount of pesticides used. The mass of TWP ultimately entering the aquatic environment strongly depends on the extent of collection and treatment of road runoff, which is highly variable. For the German highways it is estimated that up to 11,000 t/a of TWP reach surface waters. Data on TWP concentrations in the environment, including surface waters are fragmentary, which is also due to the lack of suitable analytical methods for their determination. Information on TWP properties such as density and size distribution are missing; this hampers assessing the fate of TWP in the aquatic environment. Effects in the aquatic environment may stem from TWP itself or from compounds released from TWP. It is concluded that reliable knowledge on transport mechanism to surface waters, concentrations in surface waters and sediments, effects of aging, environmental half-lives of TWP as well as effects on aquatic organisms are missing. These aspects need to be addressed to allow for the assessment of risk of TWP in an aquatic environment.

Effects of an improved biomechanical backpack strap design on load transfer to the shoulder soft tissues

The aim of the present study was to characterize shoulder strap structure and mechanical properties that may alleviate strains and stresses in the soft tissues of the shoulder. Utilizing a finite element model of the shoulder constructed from a single subject, we have quantified skin stresses exerted by backpack straps and the strains at the subclavian artery (SCA). For this end, standard shape straps with stiffness of 0.5, 1.2, and 5 MPa, were compared to the effects of optimized straps; a double-layered (soft outer layer and reinforced internal supporting layer) and newly-designed anatomically-shaped strap. Compared to the standard 0.5 MPa strap, the 5 MPa strap resulted in 4-times lower SCA strains and 2-times lower Trapezius stresses. The double-layered strap resulted in 40% and 50% reduction in SCA strains and skin stresses, respectively, with respect to the softer strap. The newly-designed anatomical strap exerted 4-times lower SCA strains and 50% lower skin stresses compared to the standard strap. This demonstrates a substantial improvement to the load carriage ergonomics when using a composite anatomical strap.

The Chemical and Products Database, a resource for exposure-relevant data on chemicals in consumer products

Quantitative data on product chemical composition is a necessary parameter for characterizing near-field exposure. This data set comprises reported and predicted information on more than 75,000 chemicals and more than 15,000 consumer products. The data's primary intended use is for exposure, risk, and safety assessments. The data set includes specific products with quantitative or qualitative ingredient information, which has been publicly disclosed through material safety data sheets (MSDS) and ingredient lists. A single product category from a refined and harmonized set of categories has been assigned to each product. The data set also contains information on the functional role of chemicals in products, which can inform predictions of the concentrations in which they occur. These data will be useful to exposure and risk assessors evaluating chemical and product safety.

Micro-sized TiO2 as photoactive catalyst coated on industrial porcelain grès tiles to photodegrade drugs in water

Pharmaceutical compounds and their metabolites raise worrying questions because of their continuous release and lack of efficient removal by conventional wastewater treatments; therefore, they are being detected in groundwater, surface water and drinking water in increasing concentrations. Paracetamol and aspirin are two of the most commonly used drugs employed as fever reducer, analgesic and anti-inflammatory. They and their metabolites are very often found in river water, so their degradation is necessary in order to render water suitable for human consumption. The present work is focused on the comparison of the photocatalytic performance of industrial active grés porcelain tiles covered with a commercial micro-sized TiO₂ by industrial process using either conventional spray deposition or innovative digital printing methods. The photodegradation of two commonly used drugs, namely aspirin and paracetamol, was investigated both individually and as a mixture, in both deionized and tap water. The results reveal the full conversion of the drugs and the significant role of the photocatalytic tiles in the mineralization processes leading to harmless inorganic species. In particular, the digitally printed tiles exhibited better photodegradation performance for both drugs compared to the spray deposited tiles. No deactivation was observed on both photocatalytic tiles.

Graphene-metal hybrid metamaterials for strong and tunable circular dichroism generation

A strong and dynamically controlled circular dichroism (CD) effect has aroused great attention due to its desirable applications in modern chemistry and life sciences. In this Letter, we propose a graphene-metal hybrid chiral metamaterial to generate mid-infrared CD with an intensity of more than 10%, which can be actively controlled over a wide wavelength range. In addition to the strong tunability, the CD signal intensity of our nanostructure is drastically larger than that of the purely graphene-based chiroptical nanostructures. Our design offers a new strategy for developing tunable chiral metadevices, which could be used in various applications, such as biochemical detection and information processing.

The leaf phenophase of deciduous species altered by land pavements

It has been widely reported that the urban environment alters leaf and flowering phenophases; however, it remains unclear if land pavement is correlated with these alterations. In this paper, two popular deciduous urban trees in northern China, ash (Fraxinus chinensis) and maple (Acer truncatum), were planted in pervious and impervious pavements at three spacings (0.5 m × 0.5 m, 1.0 m × 1.0 m, and 2.0 m × 2.0 m apart). The beginning and end dates of the processes of leaf budburst and senescence were recorded in spring and fall of 2015, respectively. The results show that leaf budburst and senescence were significantly advanced in pavement compared to non-pavement lands. The date of full leaf budburst was earlier by 0.7-9.3 days for ash and by 0.3-2.3 days for maple under pavements than non-pavements, respectively. As tree spacing increases, the advanced days of leaf budburst became longer. Our results clearly indicate that alteration of leaf phenophases is attributed to land pavement, which should be taken into consideration in urban planning and urban plant management.

Are functional fillers improving environmental behavior of plastics? A review on LCA studies

The use of functional fillers can be advantageous in terms of cost reduction and improved properties in plastics. There are many types of fillers used in industry, organic and inorganic, with a wide application area. As a response to the growing concerns about environmental damage that plastics cause, recently fillers have started to be considered as a way to reduce it by decreasing the need for petrochemical resources. Life cycle assessment (LCA) is identified as a proper tool to evaluate potential environmental impacts of products or systems. Therefore, in this study, the literature regarding LCA of plastics with functional fillers was reviewed in order to see if the use of fillers in plastics could be environmentally helpful. It was interesting to find out that environmental impacts of functional fillers in plastics had not been studied too often, especially in the case of inorganic fillers. Therefore, a gap in the literature was identified for the future works. Results of the study showed that, although there were not many and some differences exist among the LCA studies, the use of fillers in plastics industry may help to reduce environmental emissions. In addition, how LCA methodology was applied to these materials was also investigated.

Cavitation-threshold Determination and Rheological-parameters Estimation of Albumin-stabilized Nanobubbles

Nanobubbles (NBs) are of high interest for ultrasound (US) imaging as contrast agents and therapy as cavitation nuclei. Because of their instability (Laplace pressure bubble catastrophe) and low sensitivity to US, reducing the size of commonly used microbubbles to submicron-size is not trivial. We introduce stabilized NBs in the 100-250-nm size range, manufactured by agitating human serum albumin and perfluoro-propane. These NBs were exposed to 3.34- and 5.39-MHz US, and their sensitivity to US was proven by detecting inertial cavitation. The cavitation-threshold information was used to run a numerical parametric study based on a modified Rayleigh-Plesset equation (with a Newtonian rheology model). The determined values of surface tension ranged from 0 N/m to 0.06 N/m. The corresponding values of dilatational viscosity ranged from 5.10-10 Ns/m to 1.10-9 Ns/m. These parameters were reported to be 0.6 N/m and 1.10-8 Ns/m for the reference microbubble contrast agent. This result suggests the possibility of using albumin as a stabilizer for the nanobubbles that could be maintained in circulation and presenting satisfying US sensitivity, even in the 3-5-MHz range.

Generation of colorful Airy beams and Airy imaging of letters via two-photon processed cubic phase plates

In this Letter, we demonstrate the observation of colorful Airy beams and Airy imaging of letters, which we called Airy letters here, generated through the continuous cubic phase microplate (CCPP) elaborately fabricated by femtosecond laser two-photon processing. The fabricated CCPP with both micro size (60  μm×60  μm×1.1  μm) and continuous variation of phase shows a good agreement with the designed CCPP. Chromatic Airy beams and Airy letters "USTC" are experimentally generated via the CCPP illuminated by white light. In addition, superior properties of Airy letters are explored, demonstrating that the Airy letters inherit the nondiffraction, self-healing, and transverse acceleration characteristics of Airy beams. Our work paves the way toward integrated optics, light separation, optical imaging, and defective information recovery.

The application of ultrasound and enzymes in textile processing of greige cotton

A review is reported herein of the research progress made at the USDA's Southern Regional Research Center to provide an ultrasound and enzymatic alternative to the current textile processing method of scouring greige cotton textile with caustic chemicals. The review covers early efforts to measure pectin and wax removal from greige cotton textiles using standard wicking methodology and further describes an investigation of newly discovered polygalacturonase enzymes as bioscouring agents. Additional research is reviewed involving efforts to characterize and optimize the ultrasound-enhanced enzymatic scouring process through a statistical examination of the operating parameters of power, enzyme concentration, ultrasonic frequency and time.

Application of nanoparticle tracking analysis for characterising the fate of engineered nanoparticles in sediment-water systems

Novel applications of nanotechnology may lead to the release of engineered nanoparticles (ENPs), which result in concerns over their potential environmental hazardous impact. It is essential for the research workers to be able to quantitatively characterise ENPs in the environment and subsequently to assist the risk assessment of the ENPs. This study hence explored the application of nanoparticle tracking system (NTA) to quantitatively describe the behaviour of the ENPs in natural sediment-water systems. The NTA allows the measurement of both particle number concentration (PNC) and particle size distribution (PSD) of the ENPs. The developed NTA method was applied to a range of gold and magnetite ENPs with a selection of surface properties. The results showed that the positively-charged ENPs interacted more strongly with the sediment than neutral and negatively-charged ENPs. It was also found that the citrate coated Au ENPs had a higher distribution percentage (53%) than 11-mercaptoundecanoic acid coated Au ENPs (20%) and citrate coated magnetite ENPs (21%). The principles of the electrostatic interactions between hard (and soft) acids and bases (HSAB) are used to explain such behaviours; the hard base coating (i.e. citrate ions) will interact more strongly with hard acid (i.e. magnetite) than soft acid (i.e. gold). The results indicate that NTA is a complementary method to existing approaches to characterise the fate and behaviour of ENPs in natural sediment.

Incentive Policy Options for Product Remanufacturing: Subsidizing Donations or Resales?

Remanufactured products offer better environmental benefits, and governments encourage manufacturers to remanufacture through various subsidy policies. This practice has shown that, in addition to product sales, remanufactured product can also achieve its value through social donation. Based on the remanufactured product value realization approaches, governments provide two kinds of incentive policies, which are remanufactured product sales subsidies and remanufactured product donation subsidies. This paper constructs a two-stage Stackelberg game model including a government and a manufacturer under two different policies, which can be solved by backward induction. By comparing the optimal decision of the two policies, our results show that, compared with the remanufacturing sales subsidy, donation subsidy weakens the cannibalization of remanufactured products for new products and increases the quantity of new products. It reduces the sales quantity of remanufactured products, but increases their total quantity. Under certain conditions of low subsidy, the manufacturer adopting sales subsidy provides better economic and environmental benefits. Under certain conditions of high subsidy, the manufacturer adopting donation subsidy offers better economic and environmental benefits. When untreated product environmental impact is large enough, donation subsidy policy has a better social welfare. Otherwise, the choice of social welfare of these two different policies depends on the social impact of remanufactured product donated.

Democratizing science with the aid of parametric design and additive manufacturing: Design and fabrication of a versatile and low-cost optical instrument for scattering measurement

This paper focuses on the application of rapid prototyping techniques using additive manufacturing in combination with parametric design to create low-cost, yet accurate and reliable instruments. The methodology followed makes it possible to make instruments with a degree of customization until now available only to a narrow audience, helping democratize science. The proposal discusses a holistic design-for-manufacturing approach that comprises advanced modeling techniques, open-source design strategies, and an optimization algorithm using free parametric software for both professional and educational purposes. The design and fabrication of an instrument for scattering measurement is used as a case of study to present the previous concepts.

Effective media properties of hyperuniform disordered composite materials

The design challenge of new functional composite materials consisting of multiphase materials has attracted an increasing interest in recent years. In particular, understanding the role of distributions of ordered and disordered particles in a host media is scientifically and technologically important for designing novel materials and devices with superior spectral and angular properties. In this work, the effective medium property of disordered composite materials consisting of hyperuniformly distributed hard particles at different filling fractions is investigated. To accurately extract effective permittivity of a disordered composite material, a full-wave finite element method and the transmission line theory are used. Numerical results show that the theory of hyperuniformity can be conveniently used to design disordered composite materials with good accuracy compared with those materials with randomly dispersed particles. Furthermore, we demonstrate that a Luneburg lens based on the proposed hyperuniform media has superior radiation properties in comparison with previously reported metamaterial designs and it may open up a new avenue in electromagnetic materials-by-design.

Stage and continuum approaches in prehistoric biface production: A North American perspective

North American lithic analysis often assigns biface preforms to discrete, successive stages defined in Callahan’s influential study. Yet recent research questions the stage concept, emphasizing instead a continuous view of the reduction process. To compare stage and continuum approaches, their assumptions are tested in experimental replicas, including Callahan’s, and empirical Paleoindian preform assemblages. In these samples, biface reduction is a process that can be tracked and measured by continuous measures of size and reduction allometry. The process is characterized by continuous variation in the rate at which preform weight declines with preform volume. That is, weight declines at an ever-declining rate through the production process. Reduction is complex, but understood better as an allometric process than as a sequence of technological stages. “Stage” may be a useful heuristic or summary device, but preform assemblages should be analyzed in detail to reveal the continuous allometric processes that govern biface production.

Polylactides in additive biomanufacturing

New advanced manufacturing technologies under the alias of additive biomanufacturing allow the design and fabrication of a range of products from pre-operative models, cutting guides and medical devices to scaffolds. The process of printing in 3 dimensions of cells, extracellular matrix (ECM) and biomaterials (bioinks, powders, etc.) to generate in vitro and/or in vivo tissue analogue structures has been termed bioprinting. To further advance in additive biomanufacturing, there are many aspects that we can learn from the wider additive manufacturing (AM) industry, which have progressed tremendously since its introduction into the manufacturing sector. First, this review gives an overview of additive manufacturing and both industry and academia efforts in addressing specific challenges in the AM technologies to drive toward AM-enabled industrial revolution. After which, considerations of poly(lactides) as a biomaterial in additive biomanufacturing are discussed. Challenges in wider additive biomanufacturing field are discussed in terms of (a) biomaterials; (b) computer-aided design, engineering and manufacturing; (c) AM and additive biomanufacturing printers hardware; and (d) system integration. Finally, the outlook for additive biomanufacturing was discussed.

Identifying Major Transitions in the Evolution of Lithic Cutting Edge Production Rates

The notion that the evolution of core reduction strategies involved increasing efficiency in cutting edge production is prevalent in narratives of hominin technological evolution. Yet a number of studies comparing two different knapping technologies have found no significant differences in edge production. Using digital analysis methods we present an investigation of raw material efficiency in eight core technologies broadly representative of the long-term evolution of lithic technology. These are bipolar, multiplatform, discoidal, biface, Levallois, prismatic blade, punch blade and pressure blade production. Raw material efficiency is assessed by the ratio of cutting edge length to original core mass. We also examine which flake attributes contribute to maximising raw material efficiency, as well as compare the difference between expert and intermediate knappers in terms of cutting edge produced per gram of core. We identify a gradual increase in raw material efficiency over the broad sweep of lithic technological evolution. The results indicate that the most significant transition in efficiency likely took place with the introduction of small foliate biface, Levallois and prismatic blade knapping, all introduced in the Middle Stone Age / Middle Palaeolithic among early Homo sapiens and Neanderthals. This suggests that no difference in raw material efficiency existed between these species. With prismatic blade technology securely dated to the Middle Palaeolithic, by including the more recent punch and pressure blade technology our results dispel the notion that the transition to the Upper Palaeolithic was accompanied by an increase in efficiency. However, further increases in cutting edge efficiency are evident, with pressure blades possessing the highest efficiency in this study, indicating that late/epi-Palaeolithic and Neolithic blade technologies further increased efficiency.

A cohort study of the acute and chronic respiratory effects of toner exposure among handlers: a longitudinal analyses from 2004 to 2013

This study examines the acute and chronic respiratory effects of toner exposure based on markers for interstitial pneumonia, oxidative stress and pulmonary function tests. A total of 112 subjects working in a Japanese toner and photocopier manufacturing company participated in this study in 2004. We annually conducted personal exposure measurements, pulmonary function tests, chest X-ray examinations, biomarkers, and questionnaires on respiratory symptoms to the subjects. We report in this paper the results of the analysis of combined annual survey point data from 2004 to 2008 and data from three annual survey points, 2004, 2008, and 2013. During these survey periods, we observed that none of subjects had a new onset of respiratory disease or died of such a disease. In both the analyses, there were no significant differences in each biomarker and pulmonary function tests within the subjects, nor between a toner-handling group and a non-toner-handling group, except for a few results on pulmonary function tests. The findings of this study suggest that there were no acute and chronic respiratory effects of toner exposure in this cohort group, although the number of subjects was small and the level of toner exposure in this worksite was low.

Hazardous waste site frequency: use of the capture-recapture method

This investigation used a two-source capture-recapture method (CRM) for determining ascertainment and undercounts of non-national priority listed hazardous waste sites in the states of Arizona, Maine and Pennsylvania. These findings suggest that ascertainment of hazardous waste sites vary greatly, with some more accurate (i.e., Maine) than others (i.e., Pennsylvania). These data suggest that nontraditional manufacturing states (e.g., Maine) have a higher ascertainment rate than traditional manufacturing states (e.g., Pennsylvania). These results indicate that resources for locating hazardous waste sites should be more heavily allotted to industrialized areas. We suggest that the CRM is a convenient, low cost and effective method for determining (1) the accuracy of previous estimates, and (2) the number of sites in a locale with 95% confidence intervals along with an estimate of the undercount. Findings suggest that estimates of hazardous waste sites should use the CRM to determine and improve accuracy.

Amyloid Fibrils as Building Blocks for Natural and Artificial Functional Materials

Proteinaceous materials based on the amyloid core structure have recently been discovered at the origin of biological functionality in a remarkably diverse set of roles, and attention is increasingly turning towards such structures as the basis of artificial self-assembling materials. These roles contrast markedly with the original picture of amyloid fibrils as inherently pathological structures. Here we outline the salient features of this class of functional materials, both in the context of the functional roles that have been revealed for amyloid fibrils in nature, as well as in relation to their potential as artificial materials. We discuss how amyloid materials exemplify the emergence of function from protein self-assembly at multiple length scales. We focus on the connections between mesoscale structure and material function, and demonstrate how the natural examples of functional amyloids illuminate the potential applications for future artificial protein based materials.

Serum IgE elevation correlates with blood lead levels in battery manufacturing workers

Lead (Pb), an occupational and environmental toxicant, is known to induce immunomodulatory effects resulting in lowered resistance to infectious micro-organisms and altered levels of immunoglobulins in humans. Preferential activation of type-2 helper T cells and inhibition of type-1 T-cell activation is considered a cellular mechanism for the Pb-induced immune alteration, which has not been investigated well in humans. Lead's influence on in vivo balance between type-1 and type-2 activities was assessed among workers exposed to Pb through battery manufacturing in Korea. Serum IgE levels were significantly higher in the workers with a blood Pb level (PbB) of ≤30 μg/dL than in the workers with a PbB of <30 μg/dL. Furthermore, the serum IgE concentrations significantly correlated with PbB although no significant relationship between PbB and serum interleukin-4 or interferon gamma levels was observed. The present study indicates that elevation of IgE levels may be an immunologic index for Pb-induced in vivo toxicities, potentially involved with progression of various allergic diseases in humans.

Outdoor urban nanomaterials: The emergence of a new, integrated, and critical field of study

Engineered nanomaterials (ENMs) are currently widely incorporated in the outdoor urban environmental fabric and numerous new applications and products containing ENMs are expected in the future. As has been shown repeatedly, products containing ENMs have the potential, at some point in their lifetime, to release ENMs into their surrounding environment. However, the expanding body in environmental nanomaterial research has not yet shifted toward ENMs in the context of the complex outdoor urban environment. This is especially surprising because the world's human populations are on a steady march toward more and more urbanization and technological development, accompanied with increased applications for ENMs in the outdoor urban environment. Our objective for this paper is therefore to review, assess, and provide new information in this emerging field. We provide an overview of nanomaterials (NMs, encompassing both ENMs and incidental nanomaterials, INMs) that are likely to be released in the urban environment from outdoor sources by discussing 1) the applications of ENMs that may lead to release of ENMs in urban areas, 2) the recently published data on the release of ENMs from novel nano-enabled applications in the outdoor urban environment, 3) the available literature on the occurrence of INMs in the atmosphere and within/on dust particles, and 4) the potential pathways and fate of NMs in the outdoor urban environment. This review is then followed by three case studies demonstrating the importance of NMs in the outdoor urban environment. The first and second case studies illustrate the occurrence of NMs in urban dust and stormwater ponds, respectively, whereas the third case study discusses the lessons learned from the release of NMs (e.g. Pt, ph and Rh) from automotive vehicle catalytic convertors. This article ends with a discussion of the research priorities needed to advance this emerging field of "outdoor urban nanomaterials" and to assess the potential risks of NMs in the context of urban environments.

Proposal of a framework for scale-up life cycle inventory: A case of nanofibers for lithium iron phosphate cathode applications

Environmental assessments are crucial for the management of the environmental impacts of a product in a rapidly developing world. The design phase creates opportunities for acting on the environmental issues of products using life cycle assessment (LCA). However, the LCA is hampered by a lack of information originating from distinct scales along the product or technology value chain. Many studies have been undertaken to handle similar problems, but these studies are case-specific and do not analyze the development options in the initial design phase. Thus, systematic studies are needed to determine the possible scaling. Knowledge from such screening studies would open the door for developing new methods that can tackle a given scaling problem. The present article proposes a scale-up procedure that aims to generate a new life cycle inventory (LCI) on a theoretical industrial scale, based on information from laboratory experiments. Three techniques are described to obtain the new LCI. Investigation of a laboratory-scale procedure is discussed to find similar industrial processes as a benchmark for describing a theoretical large-scale production process. Furthermore, LCA was performed on a model system of nanofiber electrospinning for Li-ion battery cathode applications. The LCA results support material developers in identifying promising development pathways. For example, the present study pointed out the significant impacts of dimethylformamide on suspension preparation and the power requirements of distinct electrospinning subprocesses. Nanofiber-containing battery cells had greater environmental impacts than did the reference cell, although they had better electrochemical performance, such as better wettability of the electrode, improving the electrode's electrosorption capacity, and longer expected lifetime. Furthermore, material and energy recovery throughout the production chain could decrease the environmental impacts by 40% to 70%, making the nanofiber a promising battery cathode. Integr Environ Assess Manag 2016;12:465-477. © 2016 SETAC.

Biomaterials in Periodontal Regenerative Surgery: Effects of Cryopreserved Bone, Commercially Available Coral, Demineralized Freeze-dried Dentin, and Cementum on Periodontal Ligament Fibroblasts and Osteoblasts

The ultimate goal of periodontal therapy is to achieve successful periodontal regeneration. The effects of different biomaterials, allogenic and alloplastic, used in periodontal surgeries to achieve regeneration have been studied in vitro on periodontal ligament (PDL) cells and MC3T3-E1 cells. The materials tested included cryopreserved bone allograft (CBA), coralline hydroxyapatite (CH), demineralized freeze-dried dentin (DFDD), and cementum. CBA and CH revealed an increase in initial PDL cell attachment, whereas CH resulted in an increase in long-term PDL cell attachment. Mineral-like nodule formation was observed significantly higher in DFDD compared to other materials tested for osteoblasts. Based on the results of this in vitro study, we conclude that the materials used are all biocompatible with human PDL cells and osteoblasts, which have pivotal importance in periodontal regeneration.

Effect of cardboard under a sleeping bag on sleep stages during daytime nap

Fourteen healthy male subjects slept from 13:30 to 15:30 under ambient temperature and relative humidity maintained at 15 °C and 60%, respectively. They slept under two conditions: in a sleeping bag on wooden flooring (Wood) and in a sleeping bag with corrugated cardboard between the bag and the flooring (CC). Polysomnography, skin temperature (Tsk), microclimate, bed climate, and subjective sensations were obtained. The number of awakenings in the CC had significantly decreased compared to that in the Wood. The mean, back, and thigh Tsk, and bed climate temperature were significantly higher in the CC than that in the Wood. Subjective thermal sensations were warmer in the CC than in the Wood. These results suggest that using corrugated cardboard under a sleeping bag may reduce cold stress, thereby decreasing the number of awakenings and increasing subjective warmth; the mean, back, and thigh Tsk; and bed climate temperature.

Specific and Reversible DNA-Directed Self-Assembly of Modular Vesicle-Droplet Hybrid Materials

Modular hybrid structures functionalized to assemble in a controlled manner possess diverse properties necessary for a new generation of complex materials and applications. Here, we functionalized giant unilamellar vesicles and emulsion droplets with biotinylated single-stranded DNA oligonucleotides using streptavidin as an intermediary linker to demonstrate specific and reversible DNA-directed self-assembly into vesicle-droplet hybrid structures. A low molar percentage of PEGylated phospholipids independent of the DNA-based recognition machinery at the supramolecular surface modulated the stability of the system. The reversibility of the aggregation was demonstrated by heating the hybrid structures above the melting temperature of the conjoining double-stranded DNA in the presence of excess biotin. The application of this general assembly control system to diverse multiphase soft materials provides the mechanism to assemble complex modular hybrid systems in a controllable and reversible way, which may provide an advantage where multifunctionality is a target property.

Highly Fluorescent dye-nanoclay Hybrid Materials Made from Different Dye Classes

Nanoclays like laponites, which are commercially avaible in large quantities for a very moderate price, provide a facile solubilization strategy for hydrophobic dyes without the need for chemical functionalization and can act as a carrier for a high number of dye molecules. This does not require reactive dyes, amplifies fluorescence signals from individual emitters due to the high number of dyes molecules per laponite disk, and renders hydrophobic emitters applicable in aqueous environments. Aiming at the rational design of bright dye-loaded nanoclays as a new class of fluorescent reporters for bioanalysis and material sciences and the identification of dye structure-property relationships, we screened a series of commercial fluorescent dyes, differing in dye class, charge, and character of the optical transitions involved, and studied the changes of their optical properties caused by clay adsorption at different dye loading concentrations. Upon the basis of our dye loading density-dependent absorption and fluorescence measurements with S2105 and Lumogen F Yellow 083, we could identify two promising dye-nanoclay hybrid materials that reveal high fluorescence quantum yields of the nanoclay-adsorbed dyes of at least 0.20 and low dye self-quenching even at high dye-loading densities of up to 50 dye molecules per laponite platelet.

A Shipping Container-Based Sterile Processing Unit for Low Resources Settings

Deficiencies in the sterile processing of medical instruments contribute to poor outcomes for patients, such as surgical site infections, longer hospital stays, and deaths. In low resources settings, such as some rural and semi-rural areas and secondary and tertiary cities of developing countries, deficiencies in sterile processing are accentuated due to the lack of access to sterilization equipment, improperly maintained and malfunctioning equipment, lack of power to operate equipment, poor protocols, and inadequate quality control over inventory. Inspired by our sterile processing fieldwork at a district hospital in Sierra Leone in 2013, we built an autonomous, shipping-container-based sterile processing unit to address these deficiencies. The sterile processing unit, dubbed “the sterile box,” is a full suite capable of handling instruments from the moment they leave the operating room to the point they are sterile and ready to be reused for the next surgery. The sterile processing unit is self-sufficient in power and water and features an intake for contaminated instruments, decontamination, sterilization via non-electric steam sterilizers, and secure inventory storage. To validate efficacy, we ran tests of decontamination and sterilization performance. Results of 61 trials validate convincingly that our sterile processing unit achieves satisfactory outcomes for decontamination and sterilization and as such holds promise to support healthcare facilities in low resources settings.

Electromagnetic toroidal excitations in matter and free space

The toroidal dipole is a localized electromagnetic excitation, distinct from the magnetic and electric dipoles. While the electric dipole can be understood as a pair of opposite charges and the magnetic dipole as a current loop, the toroidal dipole corresponds to currents flowing on the surface of a torus. Toroidal dipoles provide physically significant contributions to the basic characteristics of matter including absorption, dispersion and optical activity. Toroidal excitations also exist in free space as spatially and temporally localized electromagnetic pulses propagating at the speed of light and interacting with matter. We review recent experimental observations of resonant toroidal dipole excitations in metamaterials and the discovery of anapoles, non-radiating charge-current configurations involving toroidal dipoles. While certain fundamental and practical aspects of toroidal electrodynamics remain open for the moment, we envision that exploitation of toroidal excitations can have important implications for the fields of photonics, sensing, energy and information.

The properties of thickness-twist (TT) wave modes in a rotated Y-cut quartz plate with a functionally graded material top layer

We propose the use of thickness-twist (TT) wave modes of an AT-cut quartz crystal plate resonator for measurement of material parameters, such as stiffness, density and material gradient, of a functionally graded material (FGM) layer on its surface, whose material property varies exponentially in thickness direction. A theoretical analysis of dispersion relations for TT waves is presented using Mindlin's plate theory, with displacement mode shapes plotted, and the existence of face-shear (FS) wave modes discussed. Through numerical examples, the effects of material parameters (stiffness, density and material gradient) on dispersion curves, cutoff frequencies and mode shapes are thoroughly examined, which can act as a theoretical reference for measurements of unknown properties of FGM layer.

A biomimetic underwater vehicle actuated by waves with ionic polymer-metal composite soft sensors

The ionic polymer-metal composite (IPMC) is a soft material based actuator and sensor and has a promising potential in underwater application. This paper describes a hybrid biomimetic underwater vehicle that uses IPMCs as sensors. Propelled by the energy of waves, this underwater vehicle does not need an additional energy source. A physical model based on the hydrodynamics of the vehicle was developed, and simulations were conducted. Using the Poisson-Nernst-Planck system of equations, a physics model for the IPMC sensor was proposed. For this study, experimental apparatus was developed to conduct hydrodynamic experiments for both the underwater vehicle and the IPMC sensors. By comparing the experimental and theoretical results, the speed of the underwater vehicle and the output of the IPMC sensors were well predicted by the theoretical models. A maximum speed of 1.08 × 10(-1) m s(-1) was recorded experimentally at a wave frequency of 1.6 Hz. The peak output voltage of the IPMC sensor was 2.27 × 10(-4) V, recorded at 0.8 Hz. It was found that the speed of the underwater vehicle increased as the wave frequency increased and the IPMC output decreased as the wave frequency increased. Further, the energy harvesting capabilities of the underwater vehicle hosting the IPMCs were tested. A maximum power of 9.50 × 10(-10) W was recorded at 1.6 Hz.

Reconstructing accurate ToF-SIMS depth profiles for organic materials with differential sputter rates

To properly process and reconstruct 3D ToF-SIMS data from systems such as multi-component polymers, drug delivery scaffolds, cells and tissues, it is important to understand the sputtering behavior of the sample. Modern cluster sources enable efficient and stable sputtering of many organics materials. However, not all materials sputter at the same rate and few studies have explored how different sputter rates may distort reconstructed depth profiles of multicomponent materials. In this study spun-cast bilayer polymer films of polystyrene and PMMA are used as model systems to optimize methods for the reconstruction of depth profiles in systems exhibiting different sputter rates between components. Transforming the bilayer depth profile from sputter time to depth using a single sputter rate fails to account for sputter rate variations during the profile. This leads to inaccurate apparent layer thicknesses and interfacial positions, as well as the appearance of continued sputtering into the substrate. Applying measured single component sputter rates to the bilayer films with a step change in sputter rate at the interfaces yields more accurate film thickness and interface positions. The transformation can be further improved by applying a linear sputter rate transition across the interface, thus modeling the sputter rate changes seen in polymer blends. This more closely reflects the expected sputtering behavior. This study highlights the need for both accurate evaluation of component sputter rates and the careful conversion of sputter time to depth, if accurate 3D reconstructions of complex multi-component organic and biological samples are to be achieved. The effects of errors in sputter rate determination are also explored.