Sustainable building materials-recycled aggregate and concrete: a systematic review of properties, modification techniques, and environmental impacts.

Resource utilization of construction and demolition (C&D) waste has great potential to significantly reduce the consumption of natural resources and improve the environment. Meanwhile, establishing a sound policy system and reducing production are the key ways to solve the problem of C&D waste. Numerous studies on C&D waste, recycled concrete aggregate (RA), and recycled aggregate concrete (RAC) have been reported in the literature, with few systematic summaries. From a global perspective, this paper assessed the current situation of C&D waste and the countermeasure of several major economies. Then, this paper systematically introduces the composition structure and characteristics of RA. Modification techniques from macro and micro perspectives of RA and its effect on RAC were also presented. Paper also reviews the environmental impacts of RA and RAC. The results showed that bonded mortar was the most significant defect of RA than natural aggregate (NA). Thus, RA weakened RAC's microstructure, workability, mechanical properties, and durability. The research on the modification of RA mainly focused on removing bonded mortar and enhancing bonded mortar containing physical or chemical methods. Enhancing bonded mortar was a more effective method than removing bonded mortar. Carbonation and microbially induced calcium carbonate precipitation were highly efficient and environmentally friendly for RA modification. Research progress in quantifying the environmental impacts associated with concrete from waste materials through the LCA methodology is presented. Suggestions and an outlook were given on the critical issues facing RA and RAC. We expect that this work can provide more technical support for C&D waste utilization.

Antimony precipitation and removal by antimony hyper resistant strain Achromobacter sp. 25-M.

Microbes have been confirmed to play key role in biogeochemistry of antimony. However, the impact of indigenous bacteria (from active mines) on the behavior of dissolved antimony remained poorly understood. In current study, the hyper antimony-resistant strain, Achromobacter sp. 25-M, isolated from the world largest antimony deposit, Xikuangshan antimony deposit, was evaluated for its role in dissolved Sb(V) and Sb(III) precipitation and removal. Despite of the high resistance to Sb(III) (up to 50 mM), the facultative alkaliphile, 25-M was not capable of Sb(III) oxidation. Meanwhile 25-M can produce high amount of exopolymeric substance (EPS) with the presence of Sb, which prompted us to investigate the potential role of EPS in the precipitation and removal of Sb. To this end, 2 mM of Sb(III) and Sb(V) were added into the experimental systems with and without 25-M to discern the interaction mechanism between microbe and antimony. After 96 hrs' incubation, 88% [1.73 mM (210 mg/L)] of dissolved Sb(V) and 80% [1.57 mM (190 mg/L)] of dissolved Sb(III) were removed. X-ray diffraction and energy dispersive spectroscopy analysis confirmed the formation of valentinite (Sb2O3) in Sb(III) amended system and a solitary Sb(V) mineral mopungite [NaSb(OH)6] in Sb(V) amended group with microbes. Conversely, no precipitate was detected in abiotic systems. Morphologically valentinite was bowtie and mopungite was pseudo-cubic as indicated by scanning electronic microscopy. EPS was subjected to fourier transform infrared (FT-IR) analysis. FT-IR analysis suggested that -OH and -COO groups were responsible for the complexation and ligand exchange with Sb(III) and Sb(V), respectively. Additionally, the C-H group and N-H group could be involved in π-π interaction and chelation with Sb species. All these interactions between Sb and functional groups in EPS may subsequently favore the formation of valentinite and mopungite. Collectively, current results suggested that EPS play fundamental role in bioprecipitation of Sb, which offered a new strategy in Sb bioremediation.

Modification and application of sports rehabilitation materials based on conjugated materials.

Existing elastic band materials for sports rehabilitation equipment have some deficiencies in strength, flexibility and durability, and need to be further improved. Therefore, the aim of this paper is to modify elastic bands using a conjugated material, carbon nanotubes, to improve the strength, flexibility and durability of elastic bands. In this paper, conjugated carbon nanotubes were prepared, and their elastic bands were strengthened and toughened by solvent, dispersant and functionalizer respectively under tensile testing machine and scanning electron microscope. Then the application effect of elastic band modified by conjugated materials in exercise rehabilitation was analyzed experimentally. The experimental results show that the strength of the elastic bands modified with carbon nanotubes is in the optimal range for sports rehabilitation, and the elongation at break of the test elastic band toughness index was also higher than that before modification, all of which were more than 90%. The recovery time of the elastic band after modification was long; the elastic retention rate was high, and the deformation was not easy. The satisfaction rate of different grades of elastic bands after modification was particularly high, which was not less than 95%. The research and application of elastic band modification based on conjugated material carbon nanotubes is very important for training and treatment in sports rehabilitation, which can provide better support and stability.

Activating Organic Electrode via Trace Dissolved Organic Molecules.

Organic electrode materials have gained attention for their tunable structures and sustainability, but their low electronic conductivity requires the use of large amounts of carbon additives (30 wt %) and low mass loadings (<2 mg cm-2) in electrodes. Here, we synthesize dibenzo[b,i]phenazine-5,7,12,14-tetrone (DPT) as a cathode active material for an aqueous Zn battery and find that Zn2+ storage dominates the cathode reaction. This battery demonstrates high capacity (367 mAh g-1), high-rate performance, and superlong life (12000 cycles). Remarkably, despite DPT's insulative nature, even with a high mass loading (10 mg cm-2) and only 10 wt % carbon additives, the DPT-based cathode exhibits promising performance due to trace dissolved discharge product (DPTx-). During discharge, the DPT is reduced to trace amounts of dissolved DPTx- at the cathode surface, which in turn reduces the remaining solid DPT as a redox mediator. Furthermore, dissolution-redeposition results in the reduction of DPT size and the formation of pores, further activating the electrode.

Intracellular delivery of nitric oxide enhances the therapeutic efficacy of mesenchymal stem cells for myocardial infarction.

Cell therapy by autologous mesenchymal stem cells (MSCs) is a clinically acceptable strategy for treating various diseases. Unfortunately, the therapeutic efficacy is largely affected by the low quality of MSCs collected from patients. Here, we showed that the gene expression of MSCs from patients with diabetes was differentially regulated compared to that of MSCs from healthy controls. Then, MSCs were genetically engineered to catalyze an NO prodrug to release NO intracellularly. Compared to extracellular NO conversion, intracellular NO delivery effectively prolonged survival and enhanced the paracrine function of MSCs, as demonstrated by in vitro and in vivo assays. The enhanced therapeutic efficacy of engineered MSCs combined with intracellular NO delivery was further confirmed in mouse and rat models of myocardial infarction, and a clinically relevant cell administration paradigm through secondary thoracotomy has been attempted.

Water table level controls methanogenic and methanotrophic communities and methane emissions in a Sphagnum-dominated peatland.

Peatlands are important sources of the greenhouse gas methane emissions equipoised by methanogens and methanotrophs. However, knowledge about how microbial functional groups associated with methane production and oxidation respond to water table fluctuations has been limited to date. Here, methane-related microbial communities and the potentials of methane production and oxidation were determined along sectioned peat layers in a subalpine peatland across four Sphagnum-dominated sites with different water table levels. Methane fluxes were also monitored at these sites. The results showed that mcrA gene copies for methanogens were the highest in the 10- to 15-cm peat layer, which was also characterized by the maximum potential methane production (24.53 ± 1.83 nmol/g/h). Copy numbers of the pmoA gene for type Ia and Ib methanotrophs were enriched in the 0-5 cm peat layer with the highest potential methane oxidation (43.09 ± 3.44 nmol/g/h). For the type II methanotrophs, the pmoA gene copies were higher in the 10- to 15-cm peat layer. Hydrogenotrophic methanogens and type II methanotrophs dominated the methane functional groups. Deterministic process contributed more to methanogenic and methanotrophic community assemblages in comparison with stochastic process. The level of water table significantly shaped methanogenic and methanotrophic community structures and regulated methane fluxes. Compared with vascular plants, Sphagnum mosses significantly reduced the methane emissions in peatlands. Collectively, these findings enhance a comprehensive understanding of the effect of the water table level on methane functional groups, with consequential implications for reducing methane emissions within peatland ecosystems.IMPORTANCEThe water table level is recognized as a critical factor in regulating methane emissions, which are largely dependent on the balance of methanogens and methanotrophs. Previous studies on peat methane emissions have been mostly focused on spatial-temporal variations and the relationship with meteorological conditions. However, the role of the water table level in methane emissions remains unknown. In this work, four representative microhabitats along a water table gradient in a Sphagnum-dominated peatland were sampled to gain an insight into methane functional communities and methane emissions as affected by the water table level. The changes in methane-related microbial community structure and assembly were used to characterize the response to the water table level. This study improves the understanding of the changes in methane-related microbial communities and methane emissions with water table levels in peatlands.

Effects of Cha-Cha Dance Training on Physical-Fitness-Related Indicators of Hearing-Impaired Students: A Randomized Controlled Trial.

(1) Background: The physical fitness (PF) of hearing-impaired students has always been an international research hotspot since hearing-impaired students have difficulty in social interactions such as exercise or fitness programs. Sports interventions are proven to improve the fitness levels of hearing-impaired students; however, few studies evaluating the influence of Cha-cha (a type of Dance sport) training on the PF levels of hearing-impaired students have been conducted. (2) Purpose: This study aimed to intervene in hearing-impaired children through 12 weeks of Cha-cha dance training, evaluating its effects on their PF-related indicators, thus providing a scientific experimental basis for hearing-impaired children to participate in dance exercises effectively. (3) Methods: Thirty students with hearing impairment were randomly divided into two groups, and there was no difference in PF indicators between the two groups. The Cha-cha dance training group (CTG, n = 15) regularly participated in 90-min Cha-cha dance classes five times a week and the intervention lasted a total of 12 weeks, while the control group (CONG, n = 15) lived a normal life (including school physical education classes). Related indicators of PF were measured before and after the intervention, and a two-way repeated-measures analysis of variance was performed. (4) Results: After training, the standing long jump (CONG: 1.556 ± 0.256 vs. CTG: 1.784 ± 0.328, p = 0.0136, ES = 0.8081), sit-and-reach (CONG: 21.467 ± 4.539 vs. CTG: 25.416 ± 5.048, p = 0.0328, ES = 0.8528), sit-ups (CONG: 13.867 ± 4.912 vs. CTG: 27.867 ± 6.833, p < 0.0001, ES = 2.4677) and jump rope (CONG: 52.467 ± 29.691 vs. CTG: 68.600 ± 21.320, p = 0.0067, ES = 0.6547) scores showed significant differences. (5) Conclusions: After 12 weeks of Cha-cha dance training for hearing-impaired students, the PF level of hearing-impaired students in lower-body strength, flexibility, core strength, and cardiorespiratory endurance were effectively improved; however, there was no significant change in body shape, upper-body strength, vital capacity, and speed ability.

Boosting Zn Anode Utilization by Trace Iodine Ions in Organic-Water Hybrid Electrolytes through Formation of Anion-rich Adsorbing Layers.

Aqueous Zn batteries are attracting extensive attentions, but their application is still hindered by H2 O-induced Zn-corrosion and hydrogen evolution reactions. Addition of organic solvents into aqueous electrolytes to limit the H2 O activity is a promising solution, but at the cost of greatly reduced Zn anode kinetics. Here we propose a simple strategy for this challenge by adding 50 mM iodine ions into an organic-water (1,2-dimethoxyethane (DME)+water) hybrid electrolyte, which enables the electrolyte simultaneously owns the advantages of low H2 O activity and accelerated Zn kinetics. We demonstrate that the DME breaks the H2 O hydrogen-bond network and exclude H2 O from Zn2+ solvation shell. And the I- is firmly adsorbed on the Zn anode, reducing the Zn2+ de-solvation barrier from 74.33 kJ mol-1 to 32.26 kJ mol-1 and inducing homogeneous nucleation behavior. With such electrolyte, the Zn//Zn symmetric cell exhibits a record high cycling lifetime (14.5 months) and achieves high Zn anode utilization (75.5 %). In particular, the Zn//VS2 @SS full cell with the optimized electrolyte stably cycles for 170 cycles at a low N : P ratio (3.64). Even with the cathode mass-loading of 16.7 mg cm-2 , the full cell maintains the areal capacity of 0.96 mAh cm-2 after 1600 cycles.

Gender Differences in Lower Extremity Stiffness during a Single-Leg Landing Motion in Badminton.

In general, at the same level of exercise, female athletes are three to six times more likely to injure an anterior cruciate ligament (ACL) than male athletes. Female athletes also had higher rates of ACL injury than males in a single-leg landing task after a backcourt backhand side overhead stroke in badminton. In many previous studies, stiffness of the musculoskeletal system in the lower limbs has been reported as a potential factor contributing to differences in ACL injury rates between genders. The purpose of this study was to describe the differences between genders in leg and knee stiffness in male and female athletes during a single-leg landing action after the backhand side overhead shot in the backcourt. Eight male athletes and eight female athletes participated in this test. Leg stiffness and knee stiffness were calculated separately for male and female athletes during the landing phase. The results showed that both absolute and normalized leg stiffness were lower in female athletes than in male athletes (p < 0.05). And both absolute and normalized knee stiffness were also lower than male athletes (p < 0.05). The low leg stiffness and knee stiffness demonstrated by females in this single-leg drop task compared to male athletes may indicate that females have lower dynamic leg stability than males during the drop, which may lead to hypermobility of the knee joint and may put females at a higher risk of injury in this high-risk maneuver for non-contact cruciate ligament injuries.

Molecular Tailoring of p-type Organics for Zinc Batteries with High Energy Density.

P-type organic electrode materials are known for their high redox voltages and fast kinetics. However, single-electron p-type organic materials generally exhibit low capacity despite high operating voltage and stability, while some multi-electron p-type organic materials have high theoretical capacity but low stability. To address this challenge, we explore the possibility of combining single-electron and multi-electron units to create high-capacity and stable p-type organic electrodes. We demonstrate the design of a new molecule, 4,4'-(10H-phenothiazine-3,7-diyl) bis (N,N-diphenylaniline) (PTZAN), which is created by coupling the triphenylamine molecule and the phenothiazine molecule. The resulting PTZAN||Zn battery shows excellent stability (2000 cycles), high voltage (1.3 V), high capacity (145 mAh g-1 ), and energy density of 187.2 Wh kg-1 . Theoretical calculations and in/ex situ analysis reveal that the charge storage of the PTZAN electrode is mainly driven by the redox of phenothiazine heterocycles and triphenylamine unit, accompanied by the combination/release of anions and Zn2+ .

Surgical treatment versus observation in moderate intermittent exotropia (SOMIX): study protocol for a randomized controlled trial.

BACKGROUND: Intermittent exotropia (IXT) is the most common type of strabismus in China, but the best treatment and optimal timing of intervention for IXT remain controversial, particularly for children with moderate IXT who manifest obvious exodeviation frequently but with only partial impairment of binocular single vision. The lack of randomized controlled trial (RCT) evidence means that the true effectiveness of the surgical treatment in curing moderate IXT is still unknown. The SOMIX (surgical treatment versus observation in moderate intermittent exotropia) study has been designed to determine the long-term effectiveness of surgery for the treatment and the natural history of IXT among patients aged 5 to 18 years old. METHODS/DESIGN: A total of 280 patients between 5 and 18 years of age with moderate IXT will be enrolled at Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China. After initial clinical assessment, all participants will be randomized to receive surgical treatment or observation, and then be followed up for 5 years. The primary objective is to compare the cure rate of IXT between the surgical treatment and observation group. The secondary objectives are to identify the predictive factors affecting long-term outcomes in each group and to observe the natural course of IXT. DISCUSSION: The SOMIX trial will provide important guidance regarding the moderate IXT and its managements and modify the treatment strategies of IXT. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02736526 . Registered April 13, 2016.