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This paper presents the mathematical model of screw compressors’ working process, in which the internal flow domains are divided into three kinds of fluids—the inlet fluid, the primitive volume fluid, and outlet fluid. Grid interface method and dynamic mesh technique of Computational Fluid Dynamics (CFD) theory were utilized to simulate the suction, compression, and discharge process in order to model the dynamic characteristics of the flow domains in a screw compressor. To verify that the model is numerically accurate and the simulation method is effective, experiments on the pressure-volume changes in screw compressor were carried out. The result has shown that the simulation data is in good agreement with the experimental data. Therefore, the numerical calculation model and the simulation method can be very useful for the screw compressor design and research.

A hybrid finite–discrete element method is proposed to model the rock fracture behaviour under various loading rates. Three fracture models are proposed to predict the fracture initiation and propagation for modelling the transition from continuum to discontinuum. The modelling transition from continuum to discontinuum makes the hybrid method superior to the traditional continuum-based finite element method and discontinuum-based discrete element method. Moreover, the hybrid method considers the effect of the loading rate by implementing an empirical relationship between the static strengths and the dynamic strengths derived from the dynamic rock fracture experiments. Then, the Brazilian tensile strength tests are modelled to calibrate the proposed method under various loading rate, and demonstrate its ability in modelling the dynamic rock behaviours. The Notched Brazilian Disc tests are modelled to illustrate the capabilities of the proposed method in modelling different fracture modes. The hybrid finite element method has well modelled the stress propagation, fracture initiation and propagation, even the pure mode I, pure mode II and mixed-mode I–II fractures. It is concluded that the hybrid finite element method is superior to the continuum-based finite element method and discontinuum-based discrete element method in modelling the fracture behaviours of rock under various loading rates. [ABSTRACT FROM AUTHOR]

In this research, dual-strategy biosensing of glucose was proposed based on multifunctional CuWO4 nanoparticles (CuWO4 NPs), which were prepared for the application of electrochemical and colorimetric sensing of glucose. CuWO4 NPs show large specific surface area and good conductivity as well as excellent peroxidase-like activity. A sensitive and selective electrochemical glucose biosensor was fabricated with the immobilization of glucose oxidase (GOx) on a CuWO4 NP modified electrode for enhancing the direct electron transfer behavior. A wide linear range of 0.005–1.8 mM with a low detection limit of 1.5 μM and a high sensitivity of 28.02 mA M−1 cm−2 were achieved by using the electrochemical biosensor. Meanwhile, a colorimetric and visual glucose biosensor was constructed based on the GOx/CuWO4 cascade nanozyme, which shows a linear range of 0.05–1.0 mM with excellent selectivity. CuWO4 NPs as a promising matrix open up a dual-strategy biosensor for sensitive and selective detection of glucose. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multiple factors co-shaped the profile of antibiotics and ARGs in landfill leachate. • Leachate age was crucial to the profile of antibiotics and ARGs. • Extreme abundance of the same category of ARGs occurs in the same period. • Antibiotic concentrations vary by 1–2 orders of magnitude in dry and rainy seasons. • Most of ARGs had a higher detection level in rainy season. Landfill leachate is an important source and sink of antibiotics and antibiotic resistance genes (ARGs), which poses a potential threat to human health and ecological environment. Ten antibiotics and 8 ARGs in leachates collected from Zhejiang Province, China, were systematically investigated. The effects of multiple factors were considered: leachate age, season when the leachate was sampled (dry or rainy), heavy metal concentrations, and leachate quality parameters. Leachate age was crucial to the profile of the detectable antibiotics and ARGs. The total concentration of antibiotics were in the order of macrolides > sulfonamides > tetracyclines and they decreased significantly with leachate age. Similarly, fewer ARGs were harbored in aged leachate; the order of abundance of the ARGs was mexF (11.92 ± 0.22 log 10 gene copies/L) > sul2 > Intl1 > sul1 > ermB > mefA > tetM > tetQ (9.57 ± 1.32 log 10 gene copies/L). The extreme abundances (i.e., the maxima and minima) of ARGs relating to the same class of antibiotic were always surprisingly similar and appeared in leachate of the same age. Seasonal variation greatly affected the concentrations of antibiotics in the leachate—the concentration difference between the dry and rainy seasons could reach two orders of magnitude. Heavy metal concentrations and leachate quality parameters also had important effects on the distribution of antibiotics and ARGs. Overall, the profile of antibiotics and ARGs in leachates was influenced by numerous factors, and the pollution of antibiotics and ARGs may be reduced and controlled by adjusting the environmental factors. [ABSTRACT FROM AUTHOR]

Three well-honed carbazole derivatives-based hole transport materials (HTMs) with benzene, naphthalene, and anthracene as the core were designed on the basis of the reported triphenylamine-based B101. In order to systematically explore the effect of planarity on the performance of HTMs, the properties of the materials were evaluated theoretically. The calculated results indicate that the carbazole derivatives-based HTMs (HY1–HY3) exhibit better properties than the parental B101, such as lower HOMO levels and higher hole mobility. A candidate material, HY1, with remarkable hole mobility was synthesized and applied in perovskite solar cells (PSCs) to verify the theoretical results. According to the experimental results, the power conversion efficiency (PCE) of the dopant-free HY1-based PSC device is superior to a dopant-free B101-based device, due to its low HOMO levels and high hole mobility. Especially, the addition of HY1 in Spiro-OMeTAD as mixed HTMs (Spiro-OMeTAD + 3 mg HY1) in PSC applications can yield a maximum PCE of 17.81%, significantly higher than that of the control device using Spiro-OMeTAD as HTM (16.64%). Therefore, modulating the planarity of the molecules is an effective strategy to obtain potential HTMs with deep HOMO levels and high hole mobility for improving the performance of PSC devices. [ABSTRACT FROM AUTHOR]

• The symbiosis between algae and bacteria promotes the cyanophycin production. • Cyanophycin synthase encoding gene cphA was abundant and actively expressed. • 30 % MAGs in algal-bacterial microbiota can synthetize cyanophycin. • Ammonium and nitrate can be assimilated and synthesized cyanophycin. • The potential HGT event of cphA in wastewater microbiota was identified. The algal-bacterial wastewater treatment process has been proven to be highly efficient in removing nutrients and recovering nitrogen (N). However, the recovery of the valuable N-rich biopolymer, cyanophycin, remains limited. This research explored the synthesis mechanism and recovery potential of cyanophycin within two algal-bacterial symbiotic reactors. The findings reveal that the synergy between algae and bacteria enhances the removal of N and phosphorus. The crude contents of cyanophycin in the algal-bacterial consortia reached 115 and 124 mg/g of mixed liquor suspended solids (MLSS), respectively, showing an increase of 11.7 %–20.4 % (p < 0.001) compared with conventional activated sludge. Among the 170 metagenome-assembled genomes (MAGs) analyzed, 50 were capable of synthesizing cyanophycin, indicating that cyanophycin producers are common in algal-bacterial systems. The compositions of cyanophycin producers in the two algal-bacterial reactors were affected by different lighting initiation time. The study identified two intracellular synthesis pathways for cyanophycin. Approximately 36 MAGs can synthesize cyanophycin de novo using ammonium and glucose, while the remaining 14 MAGs require exogenous arginine for production. Notably, several MAGs with high abundance are capable of assimilating both nitrate and ammonium into cyanophycin, demonstrating a robust N utilization capability. This research also marks the first identification of potential horizontal gene transfer of the cyanophycin synthase encoding gene (cphA) within the wastewater microbial community. This suggests that the spread of cphA could expand the population of cyanophycin producers. The study offers new insights into recycling the high-value N-rich biopolymer cyanophycin, contributing to the advancement of wastewater resource utilization. [Display omitted] [ABSTRACT FROM AUTHOR]

The influencing factors, products and mechanism of N -nitrosodimethylamine (NDMA) reduction by zinc (Zn) in the presence of transition-metal ions (Mn2+, Co2+ and Ni2+), were investigated. The NDMA removal by Zn was significantly improved by them, and the promoting effect of Co2+ and Ni2+ were better than Mn2+. With the decrease of pH values and dissolved oxygen concentrations, the removals of NDMA were enhanced in all reaction systems. NDMA was mainly reduced to unsymmetrical dimethylhydrazine (UDMH) in Zn and Zn/Mn2+ systems. It was mainly reduced to dimethylamine (DMA) and ammonium (NH 4 +) in Zn/Co2+ and Zn/Ni2+ systems. There were undetected products in all reaction systems. Catalytic hydrogenation was the main mechanism, and active hydrogen atom was the main active species. The presence of Mn2+, Co2+ and Ni2+ promoted the corrosion of Zn and changed the surface morphology of Zn. The formation of type I film on Zn surface was promoted in the presence of Co2+ and Ni2+, which was conducive to the continuous corrosion of Zn and hydrogen generation. While type II film which would inhibit the corrosion of Zn formed on Zn surface in the presence of Mn2+. MnO 2 , Co 3 O 4 and Ni(OH) 2 were formed in Zn/Mn2+, Zn/Co2+ and Zn/Ni2+ systems, respectively. They would facilitate more generation of active hydrogen atoms. [Display omitted] • Mn2+, Co2+ and Ni2+ could enhance the reduction of NDMA by Zn. • The amounts of products were different with different transition-metal ions. • Active hydrogen atom was the main active species. • The corrosion rates were increased and reaction interface conditions were improved. • The in-situ generated MnO 2 , Co 3 O 4 and Ni(OH) 2 would enhance the reaction. [ABSTRACT FROM AUTHOR]

A series of three‐dimensional (3D) numerical simulations are conducted to investigate the gradual failure process of molars in this study. The real morphology and internal mesoscopic structure of a whole tooth are implemented into the numerical simulations through computerized tomography scanning, digital image processing, and 3D matrix mapping. The failure process of the whole tooth subject to compressions including crack initiation, crack propagation, and final failure pattern is reproduced using 3D realistic failure process analysis (RFPA3D) method. It is concluded that a series of microcracks are gradually initiated, nucleated, and subsequently interconnect to form macroscopic cracks when the teeth are under over‐compressions. The propagation of the macroscopic cracks results in the formation of fracture surfaces and penetrating cracks, which are essential signs and manifestations of the tooth failure. Moreover, the simulations reveal that, the material heterogeneity is a critical factor that affects the mechanical properties and fracture modes of the teeth, which vary from crown fractures to crown‐root fractures and root fractures depending on different homogeneity indices. [ABSTRACT FROM AUTHOR]

Objectives: Functional impairment is a common complaint in patients with venous malformations. Equinus can occur when the venous malformation involves the lower limb, a challenging condition with only a few studies to guide treatment choices. This study was aimed to investigate the operative management of equinus associated with lower limb venous malformations. Method: Between August 2015 and September 2017, a total of 12 patients presented with equinus associated with lower limb venous malformations and underwent surgical correction. Preoperative and postoperative clinical symptoms, physical examination and orthopaedic evaluation were retrospectively reviewed. 8 patients who experienced pain underwent percutaneous sclerotherapy prior to the operation. Surgical management included gastrocnemius intramuscular aponeurotic recession, Z-lengthening of the Achilles tendon, Hoke technique and Taylor Spatial Frame external fixation. Results: There were eight female and four male patients with a mean age of 14.3 ± 5.9 years. The mean follow-up period was 34.8 ± 9 months. The range of motion of ankle dorsiflexion (with knee extended) improved for each patient (mean, 25.4 degrees; standard deviation, 8.5 degrees). No neurovascular complications were observed. Conclusion: Operative correction of equinus associated with lower limb venous malformations is safe and effective. Selective preoperative sclerotherapy is necessary for optimal outcomes. [ABSTRACT FROM AUTHOR]

Guillain–Barré syndrome (GBS) is a rare autoimmune disorder. GBS after surgical treatment of intracranial hemorrhage due to arteriovenous malformation (AVM) is even rarer. We present a 62-year-old man diagnosed with intracranial AVM and cerebral hemorrhage. He developed GBS after the operation for AVM and cerebral hemorrhage. Following surgical excision of AVM and cerebral hematoma, the patient developed generalized weakness, with subsequent quadriplegia and life-threatening dyspnea. The diagnosis was confirmed to be the acute motor–sensory axonal neuropathy subtype of GBS after cerebrospinal fluid analysis and antibody tests. The patient responded poorly to immunoglobulin and steroid therapy. His family abandoned further management and signed out of the hospital against medical advice. Despite being rare, GBS can occur after intracranial hemorrhage and surgery. Clinicians should rule out GBS when patients show no improvement or develop new neurologic [ABSTRACT FROM AUTHOR]