Kinetics and mechanisms of H2S adsorption by alkaline activated carbon

Activated carbon adsorption is widely used to remove hydrogen sulfide (H2S), one of the major odorous compounds, from gas streams. In this study, the mechanisms of H2S adsorption by alkaline activated carbon were systematically studied. Two brands of commercial activated carbons were used as H2S adsorbents. A series of designed experiments were carried outto understand on a fundamental basis the differences in H2S removal capacity observed for the two types of carbons and samples for the same carbon obtained from different batches. The physicochemical and structural characteristics of the original and exhausted activated carbons were identified using several analytical approaches (i.e., XRF, SEM, XRD, and BET). The relationships between the adsorption performances of activated carbon for H2S and its physicochemical characteristics were discussed. The kinetics of the H2S adsorption was also studied using TGA/DSC system. Both physical adsorption and chemisorption played an important role in the H2S adsorption mechanisms with the studied carbons. Chemisorption was rapid and occurred mostly at the carbon surface whereas physical adsorption was relatively slow and mostly took place at the inner pores of carbon. Carbon II demonstrated the best performance of H2S removal due to its high capacity of both physical adsorption and chemisorption. Catalytic effects of transition metals might also contribute to enhancing the H2S oxidation.     

Regulation and Reconstruction of Cell Phenotype Gradients Along the Tendon-Bone Interface

Tendon–bone interface is prevalent in the human body. It is divided into four zones: tendon (soft tissue), unmineralized fibrocartilage, mineralized fibrocartilage, and bone (hard tissue). Tendon–bone interface is characterized by a cell phenotype gradient that appears in the different zones. The cell phenotype gradients at the tendon–bone interface are orchestrated by specific intracellular molecular mechanisms, extracellular factors, immune signals, and neurovascular factors. These features have inspired scientists to design systems that mimic natural cell phenotype gradients. These biomimetic systems include the construction of cell sheets, regulation of cellular microenvironments, and the design of gradient functional scaffolds. Exploration of methods to mimic cell phenotype gradients is instructional for future clinical applications in reconstituting the tendon–bone interface. The present review elucidates the gradient composition of the tendon–bone interface. The associated regulatory mechanisms and applications are discussed, with the anticipation of creating a mise en scène for future research in interface tissue engineering.     

A GC–MSD method for analysis of dimethyl sulfate in palm oil-based esterquat

Dimethyl sulfate (DMS) is a quarternizing agent for esteramine used for the synthesis of esterquat. To date there is no reliable published method for quantification of DMS in palm-based esterquat. Esterquat is used in the formulation of personal care and textile cleaning. The process of quaternization is usually incomplete and there will be unreacted DMS. This work presents a new simple method involving solvent extraction of DMS followed by analysis with gas chromatography–mass spectrometry detector to quantify the unreacted DMS. This method was validated as per International Council for Harmonization requirements. This novel method showed good repeatability (relative standard deviation [RSD] < 5%) and inter-day with different analyst reproducibility (RSD < 5%). The limits of detection and quantification were 5 and 10 μg mL⁻¹, respectively. The accuracy of the method was evaluated by the analysis of spiked samples and it was found that good recovery was found at spiking levels of 20, 30, and 50 μg mL⁻¹ with % recovery falling within the 80%–120% acceptable limit. However, at 10 μg mL⁻¹, the percentage recovery was slightly below the recommended limit.     

Advances in Antimicrobial Microneedle Patches for Combating Infections

Skin infections caused by bacteria, viruses and fungi are difficult to treat by conventional topical administration because of poor drug penetration across the stratum corneum. This results in low bioavailability of drugs to the infection site, as well as the lack of prolonged release. Emerging antimicrobial transdermal and ocular microneedle patches have become promising medical devices for the delivery of various antibacterial, antifungal, and antiviral therapeutics. In the present review, skin anatomy and its barriers along with skin infection are discussed. Potential strategies for designing antimicrobial microneedles and their targeted therapy are outlined. Finally, biosensing microneedle patches associated with personalized drug therapy and selective toxicity toward specific microbial species are discussed.     

Femtosecond laser modification of an array of vertically aligned carbon nanotubes intercalated with Fe phase nanoparticles

Femtosecond lasers (FSL) are playing an increasingly important role in materials research, characterization, and modification. Due to an extremely short pulse width, interactions of FSL irradiation with solid surfaces attract special interest, and a number of unusual phenomena resulted in the formation of new materials are expected. Here, we report on a new nanostructure observed after the interaction of FSL irradiation with arrays of vertically aligned carbon nanotubes (CNTs) intercalated with iron phase catalyst nanoparticles. It was revealed that the FSL laser ablation transforms the topmost layer of CNT array into iron phase nanospheres (40 to 680 nm in diameter) located at the tip of the CNT bundles of conical shape. Besides, the smaller nanospheres (10 to 30 nm in diameter) are found to be beaded at the sides of these bundles. Some of the larger nanospheres are encapsulated into carbon shells, which sometime are found to contain CNTs. The mechanism of creation of such nanostructures is proposed.     

Modeling of friction-stir butt-welds and its application in automotive bumper impact performance Part 2. Impact modeling and bumper crash performance

Ever increasing requirements regarding vehicle safety have led to rapid developments in various joining process. Among FSW widely used for Aluminum alloy welded structure of car body because of their remarkable performance in welding. For a better understanding of this performance, it is necessary to determine the behavior of butt weld in service conditions. In earlier phase of this study, thermo mechanical simulations and analysis are performed to understand the thermal behavior in the FSW weld zones. The developed models are correlated against published experimental results in terms of temperature profile of the weld zone. The objectives of the second part of this work is to develop and demonstrate an FE model of bumper and crash box assembly that would improve on the current modeling techniques for the mechanical response of welds in structural problems.     

Anti‐inflammatory properties of high pressure‐assisted extracts of Grifola frondosa in lipopolysaccharide‐activated RAW 264.7 macrophages

The aim of this study was to determine the in vitro anti‐inflammatory properties of the shake extract (SE) and the high pressure‐assisted extract (PE) of the mycelia of Grifola frondosa in a lipopolysaccharide‐stimulated RAW 264.7 macrophage model. The content of total polysaccharides and β‐glucans of PE at 600 MPa (PE‐600) was 41.2 and 6.2 mg g^?1 dry weight, respectively, which were significantly higher than SE extracts. The results showed that treatment with 500 μg mL^?1 of PE by 600 MPa (PE‐600) did not reduce RAW 264.7 cell viability but did significantly inhibit the production of LPS‐induced NO, PGE₂ and intracellular ROS. The PE‐600 inhibited the activation of NF‐kB and then reduced the production of LPS‐induced TNF‐α, IL‐6 and IL‐1β in a dose‐dependent manner. Thus, the PE could be used as an alternative extraction method for improving the extraction efficacy of G. frondosa and serve as an alternative source of anti‐inflammatory agents.     

Development,testing, and evaluation of road safety poster to reduce jaywalking behavior at intersections

Jaywalking is a traffic violation that contributes significantly to vehicle–pedestrian crashes at intersections. Although public education campaigns     

Mechanisms and models for anaerobic granulation in upflow anaerobic sludge blanket reactor

Upflow anaerobic sludge blanket (UASB) reactor has been employed in industrial and municipal wastewater treatment for decades. However, the long start-up period required for the development of anaerobic granules seriously limits the application of this technology. In order to develop the strategy for rapid UASB start-up, the mechanisms for anaerobic granulation should be understood. This paper attempts to provide a up-to-date review on the existing mechanisms and models for anaerobic granulation in the UASB reactor, which include inert nuclei model, selection pressure model, multi-valence positive ion-bonding model, synthetic and natural polymer-bonding model, Capetown's model, spaghetti theory, syntrophic microcolony model, multi-layer model, secondary minimum adhesion model, local dehydration and hydrophobic interaction model, surface tension model, proton translocation-dehydration theory, cellular automaton model and cell-to-cell communication model. Based on those previous works, a general model for anaerobic granulation is also proposed. It is expected that this paper would be helpful for researchers to further develop a unified theory for anaerobic granulation and technology for expediting the formation of the UASB granules.     

A 3D Magnetic Hyaluronic Acid Hydrogel for Magnetomechanical Neuromodulation of Primary Dorsal Root Ganglion Neurons

Neuromodulation tools are useful to decipher and modulate neural circuitries implicated in functions and diseases. Existing electrical and chemical tools cannot offer specific neural modulation while optogenetics has limitations for deep tissue interfaces, which might be overcome by miniaturized optoelectronic devices in the future. Here, a 3D magnetic hyaluronic hydrogel is described that offers noninvasive neuromodulation via magnetomechanical stimulation of primary dorsal root ganglion (DRG) neurons. The hydrogel shares similar biochemical and biophysical properties as the extracellular matrix of spinal cord, facilitating healthy growth of functional neurites and expression of excitatory and inhibitory ion channels. By testing with different neurotoxins, and micropillar substrate deflections with electrophysical recordings, it is found that acute magnetomechanical stimulation induces calcium influx in DRG neurons primarily via endogenous, mechanosensitive TRPV4 and PIEZO2 channels. Next, capitalizing on the receptor adaptation characteristic of DRG neurons, chronic magnetomechanical stimulation is performed and found that it reduces the expression of PIEZO2 channels, which can be useful for modulating pain where mechanosensitive channels are typically overexpressed. A general strategy is thus offered for neuroscientists and material scientists to fabricate 3D magnetic biomaterials tailored to different types of excitable cells for remote magnetomechanical modulation.