Mechanism of trichloroethylene degradation in Fe(II)-activated peroxymonosulfate coupled with citric acid system in the presence of surfactants.

This study demonstrated that peroxymonosulfate (PMS) activated by Fe(II)/citric acid (CA) could effectively degrade trichloroethylene (TCE) in the presence of Tween-80 (TW-80) or sodium dodecyl sulfate (SDS). Significant TCE removal of 91.6% (90.1%) with 1.3 g L-1 TW-80 (2.3 g L-1 SDS) were achieved at the PMS/Fe(II)/CA/TCE molar ratio of 4/4/4/1 (20/20/20/1). TCE degradation could be greatly elevated by Fe(II) and CA addition, while the existence of surfactants restrained TCE removal and the inhibitory effect increased with the higher surfactant concentration. The tests of the electron paramagnetic resonance (EPR) and reactive radicals scavenging experiments proved that sulfate radical (SO4-•), hydroxyl radical (HO•), and superoxide radical (O2-•) were responsible for TCE degradation and SO4-• acted as the major one. The influences of initial solution pH and inorganic anions k(Cl- and HCO3-) on TCE removal were also investigated. Eventually, TCE removal in actual groundwater tests with surfactants confirmed that the PMS/Fe(II)/CA process has a huge potential of practical application in remediating the groundwater contaminated by TCE after the pretreatment by solubilization using surfactants.

High-level production of poly (ß-L: -malic acid) with a new isolated Aureobasidium pullulans strain.

Poly (ß-L: -malic acid) (PMLA) is a water-soluble polyester with many attractive properties in chemical industry and medicine development. However, the low titer of PMLA in the available producer strains limits further industrialization efforts and restricts its many potential applications. In order to solve this problem, a new strain with the distinguished high productivity of PMLA was isolated from fresh plants samples. It was characterized as the candidate of Aureobasidium pullulans based on the morphology and phylogenetic analyses of the internal transcribed spacer sequences. After the optimization of culture conditions, the highest PMLA concentration (62.27 g l(-1)) could be achieved in the shake flask scale. In addition, the contribution of the carbon flux to exopolysaccharide (EPS) and PMLA could be regulated by the addition of CaCO3 in the medium. This high-level fermentation process was further scaled up in the 10 l benchtop fermentor with a high PMLA concentration (57.2 g l(-1)) and productivity (0.35 g l(-1) h(-1)), which are the highest level in all the literature. Finally, the suitable acid hydrolysis conditions of PMLA were also investigated with regard to the production of L: -malic acid, and the kinetics of PMLA acid hydrolysis was modeled to simulate the whole degradation process. The present work paved the road to produce this multifunctional biomaterial (PMLA) at industrial scale and promised one alternative method to produce L: -malic acid in the future.

Root Canal Segmentation in CBCT Images by 3D U-Net with Global and Local Combination Loss.

Accurate root canal segmentation provides an important assistance for root canal therapy. The existing research such as level set method have made effective progress in tooth and root canal segmentation. In the current situation, however, doctors are required to specify an initial area for the target root canal manually. In this paper, we propose a fully automatic and high precision root canal segmentation method based on deep learning and hybrid level set constraints. We set up the global image encoder and local region decoder for global localization and local segmentation, and then combine the contour information generated by level set. Through using CLAHE algorithm and a combination loss based on dice loss, we solve the class imbalance problem and improved recognition ability. More accurate and faster root canal segmentation is implemented under the framework of multi-task learning and evaluated by experiments on 78 Cone Beam CT images. The experimental results show that the proposed 3D U-Net had higher segmentation performance than state of the art algorithms. The average dice similarity coefficient (DSC) is 0.952.

[Comparation between modified coblation assisted uvulopalatopharyngoplasty and conventional uvulopalatopharyngoplasty in operative complication].

OBJECTIVE: To compare the operative effectivity and incidence of postoperative complication between conventional uvulopalatopharyngoplasty (UPPP) and modified coblation assisted UPPP (M-CAUP) in treating patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). And to explore the more effective, safer and minimally invasive operative method in surgical therapy of OSAHS. METHODS: It was a controlled trial. A retrospective analysis was made on surgical complications of conventional UPPP and of M-CAUP performed on OSAHS patients from 1995 to 2010. There were 451 patients in UPPP group and 323 patients in M-CAUP group. χ(2) test and Fisher's Exact test were used in statistical analysis. RESULTS: The incidence of serious surgical complications was higher in conventional UPPP group (3.77%, 17/451) than that in M-CAUP group (0.62%, 2/323), χ(2) = 7.800, P < 0.01, while the incidence of short-term complications was higher in M-CAUP group (90.40%, 292/323) than that in conventional UPPP group (60.98%, 275/451), χ(2) = 83.186, P < 0.01. The difference of long-term complications was not statistically significant between M-CAUP group and conventional UPPP group (P = 0.1331, Fisher Exact test). There was no significant difference in incidence of asphyxia between M-CAUP group and conventional UPPP group (P < 0.01, Fisher Exact test). However, the incidence of post-operative primary hemorrhage was obviously lower in M-CAUP group than that in conventional UPPP group (3.99%, 18/451), χ(2) = 12.133, P < 0.01. While the incidence of delayed hemorrhage, temporal velopharyngeal insufficiency, and foreign body sensation at pharynx were higher in M-CAUP group (8.05%, 12.69%, 68.42%, respectively) than that in conventional UPPP group (3.77%, 3.33%, 51.00%, respectively) P < 0.01, respectively. There was no significant difference in incidence of permanent velopharyngeal insufficiency, stenosis of nasopharynx and nasopharyngeal atresia, alteration of taste, throat itch and coughing. CONCLUSION: Compared to the conventional UPPP, M-CAUP was more effective and safer in treating OSAHS with less severe complications during and after the operation.