Degradation of tetracycline wastewater by suspended biochar as carriers in moving bed biofilm reactor.

To improve the removal efficiency of antibiotics in moving bed biofilm reactor, suspended biochar block was prepared by the one-pot process and was used as carriers to construct a reaction device to study the treatment effect of antibiotic wastewater. The characteristics of the hanging biofilm in wastewater were investigated. And the mechanism of biochar as a biological carrier has been studied. The results showed that in the 45-day experiment, the maximum number of biofilms for suspended biochar carriers was twice 3.4 times that of the high-density polyethylene carriers. When 10 mg/L tetracycline was added to the reactor, the removal efficiency of the tetracycline removal rate was 71.85% and the chemical oxygen demand (COD), total nitrogen (TN), and NH4+-N removal efficiency reached to 89.95, 61.91 and 85.47% respectively. Suspension biochar carriers can reduce fluctuations in redox potentials, thereby improving the cellular efficiency of microorganisms. Meanwhile, it inhibits the production of soluble microbial products and extracellular polymers, reduces toxic effects, and enhances the adhesion between microorganisms and carriers. The microbial communities of the two carriers were investigated by high-throughput sequencing techniques. Suspended biochar significantly increased the relative abundance of Hydrogenophaga and Comamonas, and improved the ability of nitrification and denitrification. Comamonas could be responsible for tetracycline degradation.

Experimental study on new structure teeth in a high-temperature environment.

In high-temperature drilling, especially in high-temperature geothermal drilling, cone bits often experience common and severe tooth loss. This issue significantly reduces the cone bit's service life and has a detrimental impact on drilling efficiency. The quality of the fixed teeth plays a crucial role in the performance of the cone bit. In high-temperature environments, conventional methods fail to meet the requirements for securing the cone bit's teeth. Therefore, to address the tooth loss problem in high-temperature drilling, a new tapered tooth structure is proposed. Laboratory experiments were conducted to secure teeth with varying tapers at both normal and high temperatures. The results revealed that the maximum fastening force increased progressively with the degree of taper, reaching its peak at C50. Compared to conventional cylindrical teeth, the maximum fastening force increased by approximately 88.6%-271.1% at different temperatures. The tapered structure demonstrated superior tooth-fixing strength. The maximum fastening force is the smallest at 300 °C, approximately 23.7%-61.2% lower than at normal temperature. Under the same interference conditions, the maximum fastening force increased with greater taper. With interference values of 0.075, 0.095, and 0.115, the maximum fastening force increased by 48.9%-175.1%, 14%-141.6%, and 53%-271.1%, respectively, when compared to cylindrical teeth with C300, C200, C100, and C50 tapers. The tapered structure exhibited superior tooth-fixing strength and significantly enhanced tooth retention strength at high temperatures.

Blue 405 nm LED light effectively inactivates bacterial pathogens on substrates and packaging materials used in food processing.

This study investigates the antimicrobial effectiveness of 405 nm light emitting diodes (LEDs) against pathogenic Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, and Staphylococcus aureus, in thin liquid films (TLF) and on solid surfaces. Stainless steel (SS), high density polyethylene (HDPE), low density polyethylene (LDPE), and borosilicate glass were used as materials typically encountered in food processing, food service, and clinical environments. Anodic aluminum oxide (AAO) coupons with nanoscale topography were used, to evaluate the effect of topography on inactivation. The impact of surface roughness, hydrophobicity, and reflectivity on inactivation was assessed. A 48 h exposure to 405 nm led to reductions ranging from 1.3 (E. coli) to 5.7 (S. aureus) log CFU in TLF and 3.1 to 6.3 log CFU on different solid contact surfaces and packaging materials. All inactivation curves were nonlinear and followed Weibull kinetics, with better inactivation predictions on surfaces (0.89 ≤ R2 ≤ 1.0) compared to TLF (0.76 ≤ R2 ≤ 0.99). The fastest inactivation rate was observed on small nanopore AAO coupons inoculated with L. monocytogenes and S. aureus, indicating inactivation enhancing potential of these surfaces. These results demonstrate significant promise of 405 nm LEDs for antimicrobial applications in food processing and handling and the healthcare industry.

Surface Activities, Antibacterial Activity and Corrosion Inhibition Properties of Gemini Quaternary Ammonium Surfactants with Amido Group and Carboxylic Counterions.

A series of gemini quaternary ammonium surfactants containing carboxylate counterion with the formula C17H35CONH(CH2)2N+(CH3)2(CH2)2N+(CH3)2(CH2)2 NHCO C17H35·2Y (Y=HCOO-, CH3COO-, CH3CHOHCOO-) have been synthesized by a counterion conversion process and characterized by Fourier transform infrared spectroscopy and mass spectroscopy. It is found that these surfactants reduce the surface tension of water to a minimum value of 26.78 mN·m-1 at a concentration of 1.21 ×10-5 mol·L-1. TEM images reveal that aggregates with vesicles or tubular structure are spontaneously formed in these surfactants aqueous solution with the concentration of 1×10-3 mol·L-1. It is also found that they are effective corrosion inhibitors for A3 steel in acid solution and have superior antibacterial activity at a concentration of 0.1g·L-1.

Assessing the mobility of the mandibular condyle by sonography.

PURPOSE: Traditionally, the measurement of the maximal mouth opening was regarded as the mobility of the temporomandibular joint. The information, however, was not reliable. Sonography was often used to diagnose disc displacement in the temporomandibular joint and its validity was well established. The tool was also appropriate for measuring the outcome of temporomandibular disorders management. Therefore, the purpose of the study was to examine completely the reliability and error for evaluating the mobility of the mandibular condyle by sonography. In addition, the existing methods were modified to improve the repeatability. PATIENTS AND METHODS: The reliability examinations included between-image and within-image explorations to represent the reliabilities of the image capturing and the mobility measuring, respectively. Sixty-two subjects were recruited to receive ultrasonic examination for condylar mobility. The images of the condyle in mouth closing and opening were captured and the horizontal displacement of the condyles was measured as the anterior translation of the condyle. To confirm that the probe did not move during mouth opening, a marker was placed between the skin and the ultrasonic probe as the landmark. RESULTS: The results demonstrated that the intrarater and interrater reliabilities in the within-image test were 0.986 and 0.970 and the reliabilities in the between-image test were 0.904 and 0.857, respectively. The standard errors of measurement in the within-image and between-image tests were 0.04 cm and 0.09 cm, respectively. CONCLUSION: Sonography is a reliable tool to assess condylar mobility and can be used to measure the treatment outcome for temporomandibular disorders.