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Motivation The location, timing and abundance of gene expression (both mRNA and proteins) within a tissue define the molecular mechanisms of cell functions. Recent technology breakthroughs in spatial molecular profiling, including imaging-based technologies and sequencing-based technologies, have enabled the comprehensive molecular characterization of single cells while preserving their spatial and morphological contexts. This new bioinformatics scenario calls for effective and robust computational methods to identify genes with spatial patterns. Results We represent a novel Bayesian hierarchical model to analyze spatial transcriptomics data, with several unique characteristics. It models the zero-inflated and over-dispersed counts by deploying a zero-inflated negative binomial model that greatly increases model stability and robustness. Besides, the Bayesian inference framework allows us to borrow strength in parameter estimation in a de novo fashion. As a result, the proposed model shows competitive performances in accuracy and robustness over existing methods in both simulation studies and two real data applications. Availability and implementation The related R/C++ source code is available at https://github.com/Minzhe/BOOST-GP. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Molecular profiling technologies, such as genome sequencing and proteomics, have transformed biomedical research, but most such technologies require tissue dissociation, which leads to loss of tissue morphology and spatial information. Recent developments in spatial molecular profiling technologies have enabled the comprehensive molecular characterization of cells while keeping their spatial and morphological contexts intact. Molecular profiling data generate deep characterizations of the genetic, transcriptional and proteomic events of cells, while tissue images capture the spatial locations, organizations and interactions of the cells together with their morphology features. These data, together with cell and tissue imaging data, provide unprecedented opportunities to study tissue heterogeneity and cell spatial organization. This review aims to provide an overview of these recent developments in spatial molecular profiling technologies and the corresponding computational methods developed for analyzing such data. [ABSTRACT FROM AUTHOR]

• MOFs precursors were prepared via microwave irradiation and used as self-sacrificing template. • Fe, Co bimetal embedded nanoporous carbon (Fe-Co/NPC) was prepared by a rapid and scalable strategy. • Fe-Co/NPC composites showed excellent electrochemical performance as ideal electrocatalyst for OER. The development of highly efficient, stable, and low-cost non-noble-metal electrocatalysts for oxygen evolution reactions (OER) is a major challenge for facilitate the efficiency of green energy storage. Bimetallic oxides are considered promising candidates as the electrocatalysts for OER because of their remarkable electrocatalytic activity, good stability, and low cost. In this work, ZIF-67 precursors were prepared via microwave irradiation and used as a self-sacrificing template. We proposed a rapid and scalable strategy to prepare Fe, Co bimetal embedded nanoporous carbon (Fe-Co/NPC) polyhedron composites by thermal decomposition of Fe species incorporated ZIF-67 precursor. Benefiting from the distinctive 3D polyhedron structural and compositional advantages, Fe-Co/NPC with hierarchical porous structure showed excellent electrochemical performance as ideal electrode material for OER. The resulting Fe-Co/NPC displayed outstanding electrocatalytic activity for OER with appreciable onset potential (1.59 V (vs. RHE)), small Tafel slope (53.55 mV dec−1), low over-potential (396 mV) to reach 10 mA cm−2, and excellent durability with negligible loss in current density after 1000 cycles. The current work demonstrated new insight into the design and construction of 3D structured Fe-Co/NPC polyhedron catalysts with highly electrocatalytic activity and good stability for electrocatalysis applications. [ABSTRACT FROM AUTHOR]

Background: Previous cancer genomics studies focused on searching for novel oncogenes and tumor suppressor genes whose abundance is positively or negatively correlated with end-point observation, such as survival or tumor grade. This approach may potentially miss some truly functional genes if both its low and high modes have associations with end-point observation. Such genes act as both oncogenes and tumor suppressor genes, a scenario that is unlikely but theoretically possible. Results: We invented an Expectation-Maximization (EM) algorithm to divide patients into low-, middle- and high-expressing groups according to the expression level of a certain gene in both tumor and normal patients. We found one gene, ORMDL3, whose low and high modes were both associated with worse survival and higher tumor grade in breast cancer patients in multiple patient cohorts. We speculate that its tumor suppressor gene role may be real, while its high expression correlating with worse end-point outcome is probably due to the passenger event of the nearby ERBB2's amplification. Conclusions: The proposed EM algorithm can effectively detect genes having tri-modal distributed expression in patient groups compared to normal genes, thus rendering a new perspective on dissecting the association between genomic features and end-point observations. Our analysis of breast cancer datasets suggest that the gene ORMDL3 may have an unexploited tumor suppressive function. [ABSTRACT FROM AUTHOR]

The effects of Cd stress on the growth and Cd accumulation of Bougainvillea spectabilis Willd. as an ornamental plant and the related mechanisms were investigated in the study. We studied the impact of Cd on the plant ultrastructure, examined the cellular distribution of Cd, explored the Cd chemical forms and transformation, and determined the organic acid secretion in the plants. The results showed that B. spectabilis could grow well in the Cd treatment groups, and the roots could accumulate high concentration of Cd. The soluble fraction (primarily in the vacuole) as the form of citrate in leaves of B. spectabilis was the major compartment for Cd storage. The citric acid secreted by B. spectabilis played an important role in the detoxification of Cd, as well as the growth of plants and Cd accumulation. As an ornamental plant, B. spectabilis has the potential to be used in the phytostabilization of Cd-contaminated soils and can beautify the environment at the same time. [ABSTRACT FROM AUTHOR]

Motivation Synergistic drug combinations are a promising approach to achieve a desirable therapeutic effect in complex diseases through the multi-target mechanism. However, in vivo screening of all possible multi-drug combinations remains cost-prohibitive. An effective and robust computational model to predict drug synergy in silico will greatly facilitate this process. Results We developed DIGREM (Drug-Induced Genomic Response models for identification of Effective Multi-drug combinations), an online tool kit that can effectively predict drug synergy. DIGREM integrates DIGRE, IUPUI_CCBB, gene set-based and correlation-based models for users to predict synergistic drug combinations with dose–response information and drug-treated gene expression profiles. Availability and implementation http://lce.biohpc.swmed.edu/drugcombination Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Circular RNAs are a special type of RNA that has recently attracted a lot of research interest in studying its formation and function. RNA binding proteins (RBPs) that bind circRNAs are important in these processes, but have been relatively less studied. CLIP-Seq technology has been invented and applied to profile RBP-RNA interactions on the genome-wide scale. While mRNAs are usually the focus of CLIP-Seq experiments, RBP-circRNA interactions could also be identified through specialized analysis of CLIP-Seq datasets. However, many technical difficulties are involved in this process, such as the usually short read length of CLIP-Seq reads. In this study, we created a pipeline called Clirc specialized for profiling circRNAs in CLIP-Seq data and analyzing the characteristics of RBP-circRNA interactions. In conclusion, to our knowledge, this is one of the first studies to investigate circRNAs and their binding partners through repurposing CLIP-Seq datasets, and we hope our work will become a valuable resource for future studies into the biogenesis and function of circRNAs. [ABSTRACT FROM AUTHOR]

This paper studies mechanical properties and energy damage evolution of fiber-reinforced cemented sulfur tailings (CSTB) backfill. The effects of fiber length and fiber content on the stress, toughness and failure properties of the CSTB were systematically revealed. In addition, the energy index evolution law was studied, and the energy damage evolution mechanism of CSTB was revealed. The results show that the deformation failure of fiber-reinforced CSTB mainly goes through four stages: initial crack compaction, linear elastic deformation, yield failure and post-peak failure. The peak stress and residual stress of the CSTB firstly increase and then decrease with the increase of fiber content and the addition of fiber can promote the change from brittle failure to ductile failure of the CSTB. Adding appropriate amount of fiber can improve the toughness of CSTB, and the influence degree of fiber length on the toughness index of CSTB is 6mm>12mm>3mm. The total strain energy increases linearly along the variation of fiber content, while the elastic strain energy and dissipated energy increase exponentially at the peak stress point. In the process of CSTB deformation and failure, "gentle—linear growth—slow growth—rapid decline" is for elastic strain energy, while "gentle—slow growth—rapid growth—linear growth" is for dissipation energy. The damage and failure of CSTB mainly experienced four stages: initial damage, slow growth of damage, accelerated damage and damage failure, and the damage evolution curve also showed the changing characteristics of "gentle—slow growth—rapid growth—linear growth". The CSTB without added fiber showed obvious "Y-type" and "linear-type" shear failure characteristics and the phenomenon of shear cracks penetrating the backfill appeared. No big shear crack occur when it is damaged, showing that the fiber addition restrain the crack growth and improve the overall crack resistance of the CSTB. Hydration products are obviously distributed on the surface of the fiber, which indicates that the fiber will be evenly dispersed in the CSTB and form a certain bonding force with the cement-tailings matrix, thus improving the overall mechanical properties of the CSTB. [ABSTRACT FROM AUTHOR]

Evidence on the combined effect of sleep duration and grip strength on depressive symptoms is scarce. This study aimed to explore the moderating effect of grip strength on the association between sleep duration and depressive symptoms in a large cohort of middle-aged and older adults. Data were extracted from the China Health and Retirement Longitudinal Study (CHARLS) 2011–2018 wave. Grip strength and sleep duration were assessed by dynamometer and self-report, respectively. Depressive symptoms were determined by the Centre for Epidemiological Studies Depression scale (CESD-10). Multivariable cox regression model was used to explore the associations between sleep duration, and depressive symptoms, and assess moderation by grip strength. A total of 4337 participants aged 57.0 ± 8.1 years (45.1 % females) were included in this study. During the 7-year follow up period, 1508 participants developed depressive symptoms. Short sleep duration (<6 h/d) was significantly associated with an increased risk of depressive symptoms [Hazard ratio (HR):1.24, 95 % confidence interval (CI):1.09, 1.40)]. This association remained in individuals with the low (HR:1.22, 95%CI:1.00, 1.49) and middle grip strength (HR:1.32, 95%CI: 1.07, 1.63), but attenuated in individuals with high grip strength (HR:1.11, 95%CI: 0.86, 1.43). High grip strength mitigated the association between short sleep duration and higher risk of depressive symptoms. Thus, improving sleep duration and strengthening muscle strength are recommended to prevent depressive symptoms in middle-aged and older adults. • Short sleep duration significantly increases the risk of depressive symptoms. • High grip strength eliminated the negative effect of short sleep duration on depressive symptoms. • Short sleep duration increased the risk of depressive symptoms only in females or individuals aged 45–60 years. [ABSTRACT FROM AUTHOR]

This study aimed to explore the association between weekend warrior physical activity (PA) pattern and depression risk in American adults. Data of adults (n = 21,125) from NHANES 2007–2018 were used. Adults were categorized into 4 PA patterns (inactive, insufficiently active, weekend warrior, and regularly active) by self-reported PA levels. Participant characteristics in different groups were tested using the Rao & Scott adjusted χ2 test. Multivariate logistic regression models with adjustment for demographics data, behavioral factors and health condition were used to explore the association between PA patterns and depression risk. Finally, interaction analyses were conducted to test if the associations differ by gender, age, race, education level, income level and marital status. Multivariate logistic regression models showed that insufficiently active, weekend warrior and regularly active adults had 31% (OR: 0.69, 95%CI:0.54–0.88), 57% (OR: 0.43, 95%CI:0.25–0.74) and 54% (OR: 0.46, 95%CI:0.39–0.54) reduced depression risk when compared with inactive adults, respectively. When compared with regularly active adults, inactive (OR: 2.188, 95%CI:1.842–2.600) and insufficiently active (OR: 1.505, 95%CI:1.159–1.955) adults had elevated depression risk, but no significant difference was found between weekend warrior (OR: 0.949, 95%CI:0.538–1.675) and regularly active adults. Moreover, the associations did not differ by demographic variables. This study showed that adults who engaged in either regularly active pattern or weekend warrior pattern, experienced lower risk of depression compared to inactive adults. Weekend warrior and regularly active patterns showed similar benefits for lowering depression risk in adults, encouraging adults to take up PA in limited sessions. [ABSTRACT FROM AUTHOR]

Previous studies have confirmed that for cemented tailings backfill, mechanical properties are improved through the addition of fiber. However, for fiber-reinforced cemented sulfur tailings backfill (FRCSTB), physical and flow properties are still unknown. In this paper, the changes in fluidity, splitting tensile strength (STS) and uniaxial compressive strength (UCS) of cemented sulfur tailings backfill (CSTB) are analyzed in detail. Secondly, regarding the addition of glass fiber and polypropylene fiber, the changes in the fluidity, STS and UCS of the CSTB, resulting from the fiber length, fiber content and method of fiber addition used, were analyzed. Moreover, the relationship between the UCS and fiber content is established. Finally, the mechanism behind the influence of fiber and sulfur content on the mechanical properties of CSTB is revealed. The results indicate that with the increase in sulfur content, the fluidity of the tailings slurry exhibits exponential growth. During the process of increasing sulfur content, the UCS and STS of CSTB initially increase and then decrease, reaching maximum values at 12% sulfur content. Similarly, at a fiber content of 0.6%, the UCS and 28d STS of CSTB reach their maximum values. In terms of enhancing the mechanical properties of CSTB, the effectiveness of glass fibers surpasses that of polypropylene fibers. In addition, regarding the improvement of the UCS of CSTB, the mixed addition of fibers is obviously worse than that of fiber alone. However, in terms of enhancing the STS of CSTB, the mixed addition of fibers outperforms the single addition of polypropylene fiber. From a microscopic perspective, polypropylene and glass fiber are able to form strong cohesion with the cement–tailings matrix and effectively prevent the formation and expansion of pores and cracks. [ABSTRACT FROM AUTHOR]

Maternal obesity increases the risk of obesity and metabolic diseases in the offspring in early life, but the underlying mechanism has not been elucidated. The aim of this study is to explore whether lncRNA and autophagy are involved in the regulation of maternal obesity on the liver lipid metabolism of the offspring. C57BL/6 mice were fed high-fat diet (HFD) or standard chow diet (CD) for 12 weeks before the start of mating and continued until the end of the lactation period. The lipid metabolism indexes of the three-week-old offspring were detected. The RNA sequencing (RNA-seq) and western blot analysis for autophagy-related protein were performed on the offspring's liver to determine the comprehensive expression profile of lncRNA and autophagy level. In addition, AML12 cells were treated with small interfering RNA (siRNA) and rapamycin. Western blot, qRT-PCR and Oil Red O staining were used to detect protein expression, mRNA expression and lipid accumulation levels. As a result, maternal obesity leads to low expression of lncRNA Lockd and autophagy inhibition in the offspring's liver. Knockdown of lncRNA Lockd could further inhibit autophagy and aggravate lipid accumulation. Rapamycin treatment could improve lipid accumulation in AML12 cells. Our study revealed that maternal obesity caused low expression of lncRNA Lockd in the offspring's liver, and lncRNA Lockd positively regulates autophagy through the mTOR signaling pathway. This study provides new insights into the occurrence of lipid accumulation in the liver of offspring. [ABSTRACT FROM AUTHOR]

Lignin, as the second most abundant natural polymer, has not been fully utilized in the industrial field due to the complex structure and functional groups. In this paper, polyvinyl chloride (PVC) coated lignin‐silica composites (PLS) with excellent cycling performance are prepared from rice husk and PVC through the method of alkali extraction and acid precipitation and mechanical mixing process. Due to the existence of functional groups on the surface of lignin, it can be closely combined with PVC to form a stable structure. The first discharge specific capacity and Coulombic efficiency of PLS is 1436 mA h g−1 and 56 %, respectively, and the reversible capacity is 720 mA h g−1 after 200 cycles at 0.1 A g−1, showing a stable cycling performance. This work promotes the application of lignin in the SiO2/C anode material of lithium ion battery, and confirms the stable combination between PVC and organic carbon. [ABSTRACT FROM AUTHOR]

Effective disposal of phosphorus slag (PS) is crucial for ecosystem protection. Herein, this study proposed that Na 2 SO 4 (SS), Na 2 SiO 3 (NS), Na 2 CO 3 (SC) and NaOH (NH) were performed to prepare alkali-activated phosphorus slag cemented paste backfill material (AAPS-PB). The evolution mechanisms of setting time, rheological behavior and mechanical properties at different contents of various activators were systematically investigated. The mineral compositions, bonding structure, micromorphology and pore structure characteristics of AAPS-PB hydration products were further clarified by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and mercury intrusion porosimeter (MIP). Results indicated that activators were proved to significantly promote the dissolution of PS at appropriate content. NH had stronger alkali activation ability in the early hydration period, whereas NS sufficiently improved the later strength, enhanced the denseness of hydration products and refined the pore structure characteristics. This study expands the avenues for high-value applications of PS. • AAPS samples with 2.5% NS content exhibit the highest 28 days strength. • The activation effects of various activators were compared. • Cemented paste backfill technique provides new thoughts for the large consumption of PS. • The hydration mechanism of AAPS-PB was revealed. [ABSTRACT FROM AUTHOR]

Abstract Here we report an Au nanoparticles supported on nanostructured porous carbon (NPCs) hybrid through a coordination-assisted strategy. Metal-organic frameworks (MOFs) have been demonstrated as suitable precursors for preparing NPCs through the impregnation of a secondary carbon source within pores of MOFs. The thermal transformation of Au/UiO-66-NH 2 composites in an inert atmosphere has yielded ultrafine Au-embedded NPCs (Au/NPCs). The formation of these composite materials was verified by a comprehensive characterization using X-ray diffraction, N 2 adsorption, scanning electron microscopy, and transmission electron microscopy. Because of the unique structural properties and synergetic catalytic effect, Au/NPCs can be developed as an effective sensing platform for the detection of acetaminophen (AP), which showed high activity and excellent analytical performance towards AP, such as a wide linear range of 0.12–95.10 μM, a high sensitivity of 357.62 μA mM−1, and a low limit of detection of 49.4 nM. Importantly, the successfully fabricated Au/NPCs device accurately measured the amount of AP in pharmaceutical samples. Graphical abstract Unlabelled Image Highlights • The Au/NPCs hybrids were prepared by a simple one-step pyrolysis of UiO-66 particles. • It was prepared by using UiO-66 as template and the MOFs also act as carbon sources without need of additional precursors. • A sensitive biosensor for AP was developed based on the Au/NPCs–GCE, which showed good electrochemical performance. [ABSTRACT FROM AUTHOR]

Abstract The preparation of palladium nanoparticles (Pd NPs) attached on nitrogen-doping hollow carbon spheres (NHCSs) surface using polyoxometalates (POMs) as both the reductant and bridging molecules by a green strategy was described in this paper. The samples have been thoroughly comprehensive characterized using scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, energy-dispersive X-ray spectra, and X-ray photoelectron spectroscopy. The as-prepared Pd/POMs/NHCSs tri-component nanohybrids provide enhanced electro-catalytic activities for oxidation of acetaminophen (AP) with the catalytic rate constant (k cat) of 2.34 × 103 M−1s−1 and diffusion coefficient (D) of 6.18 × 10−5 cm2s−1, because of the synergetic effects of Pd NPs and NHCSs. We assessed the use of Pd/POMs/NHCSs as an effective sensing template for electrochemical detection of AP, which showed high analytical performance, such as a linear range of 0.02 μM–0.63 μM with a sensitivity of 508.46 μAmM−1; a linear range of 0.63 μM to 0.083 mM with a sensitivity of 154.27 μAmM−1, and a low limit of detection of 3 nM. This strategy provides a new direction opportunity to promote the electrochemical performance of AP. Graphical abstract The preparation of palladium nanoparticles (Pd NPs) attached on nitrogen-doping hollow carbon spheres (NHCSs) surface using polyoxometalates (POMs) as both the reductant and bridging molecules by a facile strategy. Image 1 Highlights • Decoration of NHCSs with Pd NPs using POMs by a simple and green method. • Pd/POMs/NHCSs was developed as an effective sensing platform for the detection of AP. • The novel Pd/POMs/NHCSs hybrids will hold promise in development of electrode materials. [ABSTRACT FROM AUTHOR]

• The effects of sulfur content and polypropylene fiber on the mechanical properties, failure pattern and damage evolution of the CSTB were systematically studied. • The fiber factor γ is introduced to measure the impact of polypropylene fiber on mechanical behavior of CSTB. • The piecewise damage constitutive model taking fiber factor γ into consideration was established. In order to explore the mechanical properties of cemented sulfur tailings backfill (CSTB), uniaxial compression tests of cemented sulfur tailings backfill (CSTB) were carried out in the laboratory, and the effects of sulfur content and polypropylene fiber on the mechanical properties, failure pattern and damage evolution of the CSTB were systematically studied. Moreover, fiber factor γ is introduced to measure the impact of polypropylene fiber on mechanical behavior of CSTB. The peak stress, residual stress and elastic modulus of the CSTB all increase initially and decrease afterwards with the fiber factor γ increasing. When the fiber content is 0%∼0.6%, the three factors show exponential and quadratic function with the fiber factor γ increasing. The total strain energy, elastic strain energy and dissipative strain energy of CSTB at the peak stress point all increase first and then decrease with the fiber factor γ increasing, and all reach the maximum value when the fiber content is 0.6%. Under uniaxial loading, the elastic strain energy of CSTB presents a change characteristic of "gentle - rapid increase - slow increase - rapid decline" with the increasing axial strain, while the dissipative strain energy presents a change characteristic of "gentle - steady increase - rapid increase". In addition, each strain energy (dissipative strain energy, total strain energy and total strain energy) of CSTB at the peak stress point all increase initially and decrease afterwards with the fiber factor γ increasing. Then, the piecewise damage constitutive model taking fiber factor γ into consideration was established. Under uniaxial loading, the damage evolution of backfill can be divided into four stages: no damage stage, slow growth stage, acceleration stage and damage failure stage. It shows that polypropylene fiber can effectively inhibit the damage and failure of CSTB, thus improving the bearing capacity and anti-deformation and failure ability of CSTB. The CSTB without fiber shows obvious shear failure characteristics, and there are obvious large-scale "Y-shaped" and "linear" failure cracks on the sample surface. There is not only one or two major large-scale cracks in the failure of CSTB containing fiber, but also the range of fracture surface is very limited, indicating that adding fiber can effectively inhibit the crack propagation of CSTB during failure and improve the overall anti-crack ability of CSTB. [ABSTRACT FROM AUTHOR]

• The durability and leaching behavior of rm-cpb were studied systematically. • The UCS of RM-CPB was investigated by orthogonal experiment. • The environmental impact of RM-CPB was studied by three different leaching methods. Red mud (RM) is a potential supplementary backfill material. However, little is known about cemented paste backfill (CPB) preparation from reused RM. Here, the feasibility of Bayer RM in CPB technology is discussed to expand the utilization of solid waste. With Bayer RM, Fly ash (FA), and cement as raw materials, the strength performance of Bayer RM in cemented paste backfill (RM-CPB) was evaluated by the orthogonal experiment method, and the optimal ratio of RM-CPB was determined. The effects of slurry concentration, mixing ratio of RM to FA, and the cement dosage on uniaxial compressive strength (UCS) were studied. Its durability, microstructure, permeability, and environmental properties were investigated. The experimental results show that the strength of the optimum proportion reached 1.25 MPa and 2.37 MPa after curing for 3 d and 28 d respectively and meet the mine design standard when the ratio of RM-CPB is: 60% of the slurry concentration, the RM: FA is 3:2, and the dosage of cement is 5%. RM-CPB material has good durability, and the main hydration products are C-S-H gel, ettringite, and gmelinite, which is conducive to the development of UCS of the backfill material. Meanwhile, the permeability k 20 of RM-CPB is only 6.005 × 10-6 cm/s, indicating that the material has few internal pores, which can effectively prevent external water intrusion. The leaching test results showed that both the heavy metal concentration and pH value of the leachate were within the range specified in the Chinese standard (DZ/T 0290–2015), and it was found that the effect of the three ion leaching tests is successive: toxicity leaching test > immersion test > eluviation test. The comprehensive analysis found that the reuse of Bayer RM as a supplementary cemented paste backfill material provides a new idea for the large-scale utilization of industrial solid waste. [ABSTRACT FROM AUTHOR]

• The relationship between flowing properties and sulfur content of cemented sulfur tailings backfill (CSTB) is revealed. • Based on SEM and XRD techniques, the effect of sulfur content variation on mechanical properties of cemented sulfur tailings backfill is investigated. • By adding polypropylene fibers to the CSTB, the prediction models for compressive and tensile strength are proposed considering fiber modification coefficient. • Based on SEM and XRD techniques, the effect of polypropylene fibers on mechanical properties of cemented sulfur tailings backfill is investigated. In this paper, the mechanics, flowing and microstructural properties of the cemented sulfur tailings backfill (CSTB) have been studied by means of flow performance test, uniaxial compression test, scanning electron microscope test and X-ray energy spectrum test. On the basis of previous results, a new way was proposed to improve the mechanical performance of CSTB. The research results show that the fluidity of sulfur tailings slurry increases exponentially with the increase of sulfur content, because the density of sulfide concentrate is greater than that of tailings. The adding of polypropylene fiber will reduce the fluidity of sulfur tailings slurry and the fluidity of the slurry decreases exponentially with the increase of fiber content. The compressive strength and 28d splitting tensile strength of the CSTB both increased first and then decreased with the increase of the sulfur content, and reached the maximum when the sulfur content was 12%. However, the CSTB exhibits obvious strength deterioration characteristics when the curing age exceeds 28 days. The compressive strength and 28d tensile strength of the CSTB both increased first and then decreased with the increase of fiber content, and then, reached the maximum when the fiber content is 0.6%. In addition, the effect of adding polypropylene fiber on improving the tensile strength is better than that of compressive strength. SEM and X-ray energy spectrum analysis results show that a certain amount of secondary gypsum and ettringite crystals can effectively fill the pores in the CSTB, which contributes to the development of strength. However, when the sulfur content exceeds the critical content, there are obvious pore structures and a large number of expansive minerals such as gypsum and ettringite in the CSTB, which leads to the strength deterioration of the CSTB. The special spatial skeleton structure formed by polypropylene fibers in the CSTB matrix can play a significant physical reinforcement effect and the reinforcement effect is mainly controlled by the bonding effect between the fiber and the CSTB matrix interface. In addition, the compressive strength, tensile strength and fluidity prediction models of the fiber reinforced CTSB constructed based on the fiber modification coefficient can accurately predict the compressive strength, tensile strength and fluidity parameters, which can provide certain guidance for engineering applications. [ABSTRACT FROM AUTHOR]

• The energy parameters at characteristic stress point for diffetent curing ages was studied. • The energy damage evolution mechanism of the CTB was revealed. • An energy criterion for strength failure of the CTB was established. This study attempted to explore, at curing age, the characteristics stress and energy evolution of the cemented tailings backfill (CTB) under uniaxial compression. Based on the energy consumption theory, the energy parameters at the characteristic stress varing with the curing age was analyzed. Furthermore, the evolution law of energy distribution and the energy damage mechanism of the CTB were revealed, and the failure criterion of the CTB was established based on the elastic energy consumption ratio. The results showed that the characteristic stress of the CTB follow an exponential function increasing law with the increase of curing age and the characteristic stress of the CTB with larger cement-to-tailings (c/t) ratio increases more rapidly when the curing age is 3d ~ 14d. The total energy, elastic strain energy and consumption energy at the peak stress point of the CTB all follow the exponential function increasing law with the increase of curing age, and the increase of cement-to-tailings (c/t) ratio and curing age can significantly improve the energy storage limit of the CTB. The deformation and failure of the CTB mainly go through five stages: initial crack compaction stage, linear elastic deformation stage, steady development stage of microcrack, accelerated crack expansion stage and post-peak failure stage. According to the damage value D of the CTB and the growth law of dissipated energy, elastic strain energy and axial strain, the loading damage of cemented CTB can be divided as follow: initial damage stage, damage stationary stage, damage stable stage, damage rapid stage and damage failure stage. The slow growth and abrupt change of the elastic energy consumption ratio K in the post-peak stage can be used as the criterion for strength instability of the CTB. [ABSTRACT FROM AUTHOR]