RESUMO
Abundance of dominant-flocculated-species is the key to determine coagulation performance of coagulant. Titanium-based coagulants have garnered considerable attention due to their high coagulation efficiency, but with a current challenge of the identification and isolation of the dominant-flocculated-species. Herein, polytitanium chloride (PTC), enriched with dominant-flocculated-species, was successfully synthesized by electrodialysis through accurate micro-interface control of the reaction among Ti-hydrolyzed-species and OH-. Special attention was paid to a feasible and high-effective strategy to isolate the dominant-flocculated-species from PTC through one-step rapid ultrafiltration. Selective preference was the ultrafiltration membranes (made of polyethersulfone) with a molecular weight cut-off of 5 kDa, which enabled the isolation of the dominant-flocculated-species, named PTC-5k. Results from the electrospray time-of-flight mass spectrometry (ESI-TOF-MS) proved a large proportion of the small and medium-sized hydrolyzed products as dominant-flocculated-species in PTC-5k, with the main signals concentrated between m/z 100 and 500. This composition achieved approximately 15.0% higher removal of organic matter with a 33.0% reduction in dosage compared to PTC. Unique snowflake-like branched structure of PTC-5k enhanced the coagulation mechanisms of sweeping and adsorption-bridging flocculation. Worth noting was the more compact flocs formed by PTC-5k than PTC, which was the probable reason for the mitigated fouling of ceramic membrane when PTC-5k was utilized as pre-treatment methodology. Continuous operation of ceramic membrane filtration up to 30 h, demonstrated 30% improvement in stable flux compared to PTC. This study provides the strategy for the isolation of Ti-dominant-flocculated-species, and lays the foundation for practical application.
RESUMO
In this paper, a new mechanical-based experimental method is proposed to determine the corrosion initiation and subsequent corrosion behavior of steel in simulated concrete pore solutions. The proposed experiment is used to investigate the corrosion of the steel wire under various different conditions and to examine the effects of pre-stress level in steel wire, passivation time of steel wire, composition and concentration of simulated concrete pore solution on the corrosion initiation, and subsequent corrosion development in the steel wire. The experimental results show that the reduction rate of the cross-section area of the steel wire increases with the increase of chloride concentration or decrease of pH value in the solution. However, for the case where the chloride concentration is high and the pH value is low, there is a slight decrease in the corrosion rate due to the coating function of the corrosion products surrounding the wire.
RESUMO
OBJECTIVE: To explore the relationship between the relevant factors and prostate cancer among Hui and Han populations. METHODS: The study involved 267 prostate cancer patients as cases (214 cases from Han population and 53 cases from Hui population) and 534 prostatic hyperplasia patients as controls (428 cases from Han population and 106 cases from Hui population). All the patients were collected from the General Hospital of Ningxia Medical University during January of 2007 to September of 2013. The level of fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), total prostate specific antigen (T-PSA), free prostate specific antigen (F-PSA) and free/total prostate specific antigen (F/T-PSA) were collected from the clinical medical records of the patients. Data were analyzed by the conditional logistic regression method, and attributable risk proportion(ARP) was calculated. RESULTS: In Hui population, the risk of prostate cancer for drinkers was 20.48 times higher than the non-drinkers (35.8% (19/53) to 5.7% (6/106), OR = 20.48, 95% CI: 4.95-84.66). The high level of F-PSA significantly increased the risk of prostate cancer for Hui group (83.0% (44/53) to 55.7% (59/106), OR = 4.27, 95%CI: 1.18-15.43). In contrast, the high TG level decreased the risk of prostate cancer for Hui group (18.9% (10/53) to 20.8% (22/106), OR = 0.24, 95% CI: 0.07-0.83). In Han population, the risk of prostate cancer for smokers was 1.89 times higher than the non-smokers (55.1% (118/214) to 39.7% (170/428), OR = 1.89, 95% CI: 1.28-2.78). Either high level of T-PSA or F-PSA increased the risk of prostate cancer for Han group (86.4% (185/214) to 53.7% (230/428),OR = 2.34, 95%CI:1.22-4.52;85.5% (183/214) to 56.1% (240/428), OR = 2.43, 95% CI:1.29-4.59). However, the high TG level or high ratio of F/T-PSA decreased the risk of prostate cancer (15.4% (33/214) to 18.7% (80/428), OR = 0.59, 95% CI:0.36-0.98; 53.3% (114/214) to 73.4% (314/428), OR = 0.53, 95% CI:0.36-0.78). The APRs of drinking and high level of F-PSA in Han populations were 66.6%, 62.4% in Hui populations , and the APRs of smoking and high level of T-PSA, high level of F-PSA were 33.8%, 71.3%, 67.3% in Han populations. CONCLUSION: Both drinking and high level of F-PSA might be the risky factors of prostate cancer while the high TG level might be protective factor for Hui group. However, for Han population, smoking, high T-PSA level, and high F-PSA level might be risky factors for prostate cancer while the high TG level and high ratio of F/T-PSA might be protective factors. In summary, the clinical relevant factors of prostate cancer may play different roles between Hui and Han populations in Ningxia region.
