Synthesis, supramolecular aggregation, and NIR-II phosphorescence of isocyanorhodium(i) zwitterions.

Development of new second near-infrared (NIR-II, 1000-1700 nm) luminophores is highly desirable, and d8 square-planar metal complexes with NIR-II phosphorescence have been rarely reported. Herein, we explore an asymmetric coordination paradigm to achieve the first creation of NIR-II phosphorescent isocyanorhodium(i) zwitterions. They show a strong tendency for aggregation in solution, arising from close Rh(i)⋯Rh(i) contacts that are further intensified by π-π stacking interactions and the hydrophilic-hydrophobic effect. Based on such supramolecular aggregation, zwitterions 2 and 5 are found to yield NIR-II phosphorescence emissions centered at 1005 and 1120 (1210, shoulder) nm in methanol-water mixed solvents, respectively. These two bands show red shifts to 1070 and 1130 (1230, shoulder) nm in the corresponding polymer nanoparticles in water. The resulting polymer nanoparticles can brighten in vivo tumor issues in the NIR-II region with a long-circulating time. In view of the synthetic diversity established by the asymmetric coordination paradigm, this work provides an extraordinary opportunity to explore NIR-II luminophores.

Survey on Hand-Based Haptic Interaction for Virtual Reality.

Interacting with virtual objects with haptic feedback directly using the user's hand (hand-based haptic interaction) has attracted increasing attention. Due to the high degrees of freedom of the hand, compared with tool-based interactive simulation using a pen-like haptic proxy, hand-based haptic simulation faces greater challenges, mainly including higher motion mapping and modeling difficulty of deformable hand avatars, higher computational complexity of contact dynamics, and nontrivial multi-modal fusion feedback. In this article, we aim to review key computing components for hand-based haptic simulation, and draw out major findings in this direction while analyzing the gaps toward immersive and natural hand-based haptic interaction. To this end, we investigate existing relevant studies on hand-based interaction with kinesthetic and/or cutaneous display in terms of virtual hand modeling, hand-based haptic rendering, and visuo-haptic fusion feedback. By identifying current challenges, we finally highlight future perspectives in this field.

Configuration-based Optimization for Virtual Hand Haptic Simulation.

Interacting with virtual objects via haptic feedback using the user's hand directly (virtual hand haptic interaction) provides a natural and immersive way to explore the virtual world. It remains a challenging topic to achieve 1 kHz stable virtual hand haptic simulation with no penetration amid hundreds of hand-object contacts. In this paper, we advocate decoupling the high-dimensional optimization problem of computing the graphic-hand configuration, and progressively optimizing the configuration of the graphic palm and fingers, yielding a decoupled-and-progressive optimization framework. We also introduce a method for accurate and efficient hand-object contact simulation, which constructs a virtual hand consisting of a sphere-tree model and five articulated cone frustums, and adopts a configuration-based optimization algorithm to compute the graphic-hand configuration under non-penetration contact constraints. Experimental results show both high update rate and stability for a variety of manipulation behaviors. Non-penetration between the graphic hand and complex-shaped objects can be maintained under diverse contact distributions, and even for frequent contact switches. The update rate of the haptic simulation loop exceeds 1 kHz for the whole-hand interaction with about 250 contacts.

Polysorbate-80 pretreatment contributing to volatile fatty acids production associated microbial interactions via acidogenic fermentation of waste activated sludge.

Polyoxyethylene dehydration sorbitol monooleate (polysorbate-80) pretreatment enhanced volatile fatty acids (VFAs) production of waste activated sludge (WAS) in acidogenic fermentation. The results showed that polysorbate-80 ameliorated WAS solubilization obviously with a soluble chemical oxygen demand (SCOD) increasing to 1536 mg/L within 4 h. Within 2 days of acidogenic fermentation, the maximal VFAs arrived to 2958.35 mg COD/L via polysorbate-80-pretreatment. The polysorbate-80 pretreatment boosted microbial diversity and richness in fermentation process. The Clostridium, Macellibacteroides and Acidocella strengthened microbial cooperation for the metabolic functions enhancement (e.g. amino acid metabolism and carbohydrate metabolism) for VFAs generation from WAS organics. Overall, the polysorbate-80 could play positive roles on the transformation of organic matter from sludge solid matters to VFAs, which was turned out to become an effective enhancing strategy for future WAS treatment / bioresource recovery with relatively low cost.

Synergistic pretreatment of CaO and freezing/thawing to enhance volatile fatty acids recycling and dewaterability of waste activated sludge via anaerobic fermentation.

To avoid the generally deteriorated dewaterability of sludge in waste activated sludge (WAS) anaerobic acidogenesis, the combination of varied calcium oxide (CaO) dosage (i.e., 0.01-0.07 g/g TS) and freezing/thawing pretreatment (5 F/T cycles) was investigated for concurrently improving the production of volatile fatty acids (VFAs) and dewatering performance of sludge. The highest release of soluble chemical oxygen demand (SCOD) (1836 ± 96 mg/L) and accumulation of VFAs (448.0 mg COD/g VS) were reached through the co-pretreatment of CaO (0.07 g/g TS) and F/T (50 h at -24 °C) (i.e., 0.07 CaO-F/T). Meanwhile, optimal dewaterability of sludge was also achieved in 0.07 CaO-F/T co-pretreated WAS fermentation, which was reflected by large particle size (98.32 µm), low capillary suction time (41.6 s), decreased specific resistance to filtration (SRF, reduced 47.5% against blank) and high zeta potential (-9.59 mV). Co-pretreatment of CaO and F/T reduced the species number of total microbial population, but improved the abundance of acid-producing bacteria. Increased abundance of Bacteroides, Macellibacteroides, Petrimonas, Prevotella, Clostridium, and Megasphaera was positively relevant to the high yields of VFAs. The economic analysis indicated that CaO-F/T was economically acceptable with considerable estimated net profits, which provided a feasible and efficient alternative for further WAS treatment at large scale.

Revealing microbial mechanism associated with volatile fatty acids production in anaerobic acidogenesis of waste activated sludge enhanced by freezing/thawing pretreatment.

This study investigated the association of volatile fatty acid (VFA) production with microbial mechanism in waste activated sludge (WAS) anaerobic acidogenesis enhanced by freezing/thawing (F/T) pretreatment. WAS solubilization was enhanced with 955.4 ± 10.0 mg/L soluble chemical oxygen demand (SCOD) release by a 50-h F/T pretreatment at -24 °C. The highest level of VFAs (4852 ± 156 mg COD/L) was obtained after a 12-day fermentation. Moreover, phyla of Proteobacteria, Bacteroidetes, Firmicutes, and Ignavibacteriae played vital roles in VFA generation, while high genera abundance of Clostridium, Macellibacteroides, Prevotella, and Megasphaera were positively associated with high yields of short-chain (C2-C5) fatty acids. A schematic diagram was drawn to illustrate the microbial mechanism of enhanced VFA generation by F/T pretreatment during WAS fermentation. This study provides an in-depth exploration of promoting bio-resource recycling from WAS with a low-cost approach (specially in high latitudes) and bring about some new thinking on future WAS management.

Effect of Temperature on the Absolute and Discrimination Thresholds of Voltage on Electrovibration Tactile Display.

Multi-dimensions tactile displays, such as thermal and texture display, are desirable for enhancing perception while users experience virtual shopping such as touching a garment in virtual reality. Understanding the effect of one dimension on the other is fundamental for design of multi-dimensions tactile display. In this article, we report the effect of temperature on thresholds of voltage applied on an electrovibration tactile display. Three temperatures of the electrovibration tactile display at 18°C (cold), 30°C (neutral) and 38°C (warm) were considered in two experiments. In Experiment I, we measured the absolute thresholds of square wave voltage with 25 Hz, 140 Hz and 485 Hz. In Experiment II, we measured the amplitude discrimination thresholds of same voltage signals as in Experiment I. The results show that the absolute thresholds differed significantly between 18°C and 38°C for all the three frequencies. No significant difference in the absolute threshold was found between 18°C and 30°C, except for the 485 Hz voltage. The amplitude discrimination thresholds were essentially constant except for that of the 485 Hz voltage at 18°C, which were 17.11 Vpp and 16.86 Vpp larger than those at 30°C and 38°C, respectively.

Recyclable Crosslinked High-Performance Polymers via Adjusting Intermolecular Cation-π Interactions and the Visual Detection of Tensile Strength and Glass Transition Temperature.

Crosslinked high-performance polymers have many industrial applications but are difficult to recycle. Visual detection of the physical properties of the crosslinked high-performance polymers is useful, but is difficult to achieve. The crosslinked high-performance polymers (SPIN) are constructed by using cation-π interactions. The cation-π interaction between the polymer side chains can be easily installed and removed by aqueous treatments at high or low pH, respectively, which endow the crosslinked polymer with a recyclable behavior. Additionally, the tensile strength and glass transition temperature of the SPIN films could be visually detected by taking advantage of the transparency decreasing effect of cation to an adjacent indole unit.