Combined Effect of NZVI and H2O2 on the Cyanobacterium Microcystis aeruginosa: Performance and Mechanism.

In order to eliminate the harmful cyanobacterium Microcystis aeruginosa and the algal organic matters (AOMs) produced by M. aeruginosa, the combined process of nanoscale zero-valent iron (NZVI) and hydrogen peroxide (H2O2) has been carried out, and the removal mechanism has also been clarified. As the initial cyanobacterial cell concentration is 1.0 (±0.05) × 105 cells·mL-1, all the treatments of NZVI, H2O2, and NZVI/H2O2 have inhibition effects on both the Chl a contents and photosynthetic pigments, with the Chl a removal efficiency of 47.3%, 80.5%, and 90.7% on the 5th day, respectively; moreover, the variation of ζ potential is proportional to that of the Chl a removal efficiency. The malondialdehyde content and superoxide dismutase activity are firstly increased and ultimately decreased to mitigate the oxidative stress under all the treatments. Compared with NZVI treatment alone, the oxidation of the H2O2 and NZVI/H2O2 processes can effectively destroy the antioxidant enzyme system and then inactivate the cyanobacterial cells, which further leads to the release of photosynthetic pigments and intracellular organic matters (IOM); in addition, the IOM removal efficiency (in terms of TOC) is 61.3% and 54.1% for the H2O2 and NZVI/H2O2 processes, respectively. Although NZVI is much more effective for extracellular organic matters (EOM) removal, it is less effective for IOM removal. The results of the three-dimensional EEM fluorescence spectra analysis further confirm that both H2O2 and NZVI/H2O2 have the ability to remove fluorescent substances from EOM and IOM, due to the oxidation mechanism; while NZVI has no removal effect for the fluorescent substances from EOM, it can remove part of fluorescent substances from IOM due to the agglomeration. All the results demonstrate that the NZVI/H2O2 process is a highly effective and applicable technology for the removal of M. aeruginosa and AOMs.

A preliminary study of the surgical approach for posterior tibial plateau fractures: Based on posterior fragment segment classification.

PURPOSE: The optimal surgical approach for the posterior tibial plateau fractures (PTPFs) remains controversial. This study aims to establish a method for posterior fragment segment classification to guide the choice of surgical approach and to reveal the outcome of their early reduction and health status. METHODS: The medical records of 42 PTPFs patients treated with the strategy were collected retrospectively from December 2017 to December 2021. The posterior cortex of the tibial plateau was classified into postero-medial (PM), postero-central (PC), and postero-lateral (PL) segments. A posteromedial inverted L-shaped approach was adopted when the fractures involved the PM segment in the presence or absence of PC. The Frosch approach was performed when the PL segment was concerned. Fractures containing both PM and PL segments were treated by combined approaches. Four factors were measured to evaluate the reduction effect, including medial proximal tibial angle (MPTA), lateral posterior slope angle (LPSA), medial posterior slope angle (MPSA), and articular step-off. The Short Form 36 (SF-36) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were completed at the last follow-up to assess health status and the degree of osteoarthritis. RESULTS: A posteromedial inverted L-shaped approach was adopted in 16 PTPFs patients, a Frosch approach was adopted in 14 PTPFs patients, and a combined approach was adopted in 12 PTPFs patients. Immediate radiographic results indicated a promising fixation performance with this treatment strategy. The results of SF-36 and WOMAC scores reported good health status in all patients with a mean follow-up time of 34.50 (23-50) months. Two patients developed superficial wound infections, and one patient had liquefaction necrosis in adipose tissue. Although skin numbness occurred in 4 patients, they recovered within 6 months. CONCLUSION: PTPFs patients treated under the guidance of posterior fragment segment classification achieved encouraging levels of immediate fixation and health status.

A hierarchical Bayesian model for decomposing the impacts of human activities and climate change on water resources in China.

Human activities and climate change are two key factors influencing the variation of the total amount of available surface and groundwater, hereafter termed water resources. Quantitatively separating their impacts remains a challenge. To this end, we used time-varying Budyko-type equations and a hierarchical Bayesian model in this paper to separate their impacts in 31 provincial-level divisions of China. The time-varying Budyko-type equations treat the Budyko equation parameter w as a variable, which depends on human activities (represented by per capita gross regional production) and climate change (represented by temperature and precipitation). The hierarchical model quantifies the uncertainty of parameters and the interrelation between covariates across regions in China. The results show that the time-varying Budyko-type equation can improve the fitting capability for water resources in China. The hierarchical Bayesian model, which considered spatial dependence, reduced the uncertainty of the parameters compared to spatially independent counterparts. For most regions of China, human activities reduce water resources while climate change increases them. Southeastern China is the most influenced area, and its water resources decreased approximately 50 mm because of human activities. This study can provide a basis for water resource management under climate change and human activity constraints in China.

Preparation of thermo/redox/pH-stimulative poly(N-isopropylacrylamide-co-N,N'-dimethylaminoethyl methacrylate) nanogels and their DOX release behaviors.

Stimuli-sensitive drug delivery systems show beneficial features of both medical and pharmaceutical fields. In this article, polymeric nanogel P (N-isopropylacrylamide-N,N '-dimethylaminoethyl methacrylate [NIPAM-DMAEMA]) (PND) with pH/redox/thermo-responsivenesses was synthesized by the in situ polymerization of NIPAM and DMAEMA for the controlled release of doxorubicin hydrochloride (DOX) and N,N '-bis(acryloyl)cystamine (BAC) and N,N '-methylenebisacrylamide (MBA) act as the crosslinkers, respectively. The structure, size, and zeta potential of PND-BAC and PND-MBA were further characterized. Moreover, after loading DOX, the encapsulation efficiency and the in vitro release behavior of PND-BAC/DOX and PND-MBA/DOX nanogels were discussed in detail. Compared to PND-MBA NGs, PND-BAC nanogels have redox degradability due to the presence of the crosslinker BAC. After loading DOX, the PND-BAC/DOX nanogel showed a higher encapsulation efficiency (81.6 ± 1.2)% and thermo- and pH-responsiveness as well as redox-responsive in vitro release. These properties together with excellent environmentally sensitive properties make PND-BAC as an attractive candidate for application in drug nanocarriers for the targeted drug delivery of model payloads. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1195-1203, 2019.

Curative effect of knee arthroplasty on patients with osteoarthritis and analysis of long-term joint function of these patients.

BACKGROUND: The aim of this study was to explore the curative effect of knee arthroplasty on patients with osteoarthritis and analysis of their long-term joint function. METHODS: Ninety-six cases of osteoarthritis patients, collected in our hospital from June 2010 to May 2011, were divided into control group and observation group (N.=48 in each group). Patients in observation group were treated by knee replacement, and patients in control group were treated by arthroscopic debridement. Bleeding during operation of patients and the operation time in both groups were comparable during their followed up for 6~60 months, with an average of 52 months. Neer score was used to compare the curative effect of patients after 6 months; knee society score (KSS) was used to compare knee joint function and knee joint of motion (ROM) of patients several days prior to surgery and after 6 months, 12 months, 24 months, and 48 months. Visual analogue scale (VAS) was used to compare pain degrees of patients at the last follow-up. RESULTS: By Neer score comparison, after 6 months excellent and good rate of patients in observation group (91.67%) was obviously higher than that of control group 70.83% (P<0.05); ROM of patients in observation group was obviously higher than that in control group (P<0.05); After six months, KSS score of patients in both groups greatly improved. As well, with the extension of time, their knee joint function showed a better trend, and KSS score of patients in observation group was obviously higher than that of control group (P<0.05). Pain of patients in observation group was significantly lower than that in control group (P<0.05). CONCLUSIONS: Both arthroscopy debridement and knee replacement have good curative effect. The curative effect of knee replacement was better, postoperative knee joint activity was obviously improved, the long-term recovery of knee joint function was good, and knee replacement can reduce the pain of the patients.

[Surgical treatment for talar neck fracture of Hawkins III, IV type with compression hollow screws combined with external fixator].

OBJECTIVE: To investigate the clinical effects of compression hollow screws combined with external fixator in treating talar neck fracture of Hawkins III, IV type. METHODS: From March 2010 to August 2014, 15 patients with talar neck fractures of Hawkins III, IV type were treated by open reduction and compression hollow screws fixation complicated with external fixator fixation. Including 9 males and 6 females, aged from 17 to 65 years old with an average of 37.5 years old. There were 9 cases of Hawkins III and 6 cases of Hawkins IV type. Postoperative radiographs and CT of ankle were used to evaluate the fracture healing and talar necrosis. The function of ankle and foot were evaluated by American Society of Ankle and Foot Surgery(AOFAS). RESULTS: All the patients were followed up for 8 to 55 months with an average of 23.5 months and all fractures got bone healing from 13 to 38 weeks with an average of (17.99±6.81) weeks. Traumatic arthritis occurred in 7 cases and talar necrosis in 6 cases (2 cases of type III and 4 cases of type IV) after operation. The average AOFAS score was 61.80±18.75, including excellent in 4 cases, good in 2 cases, fair in 4 cases and poor in 5 cases. CONCLUSIONS: Talar neck fracture with Hawkins III, IV type has large possibility to develop avascular necrosis. Hollow compression screw combined with external fixation may late weight-bearing for ankle and can sufficiently guarantee bone healing time, and achieve good results for the treatment of talar neck fracture.

Influence of Sub-Daily Variation on Multi-Fractal Detrended Fluctuation Analysis of Wind Speed Time Series.

Using multi-fractal detrended fluctuation analysis (MF-DFA), the scaling features of wind speed time series (WSTS) could be explored. In this paper, we discuss the influence of sub-daily variation, which is a natural feature of wind, in MF-DFA of WSTS. First, the choice of the lower bound of the segment length, a significant parameter of MF-DFA, was studied. The results of expanding the lower bound into sub-daily scope shows that an abrupt declination and discrepancy of scaling exponents is caused by the inability to keep the whole diel process of wind in one single segment. Additionally, the specific value, which is effected by the sub-daily feature of local meteo-climatic, might be different. Second, the intra-day temporal order of wind was shuffled to determine the impact of diel variation on scaling exponents of MF-DFA. The results illustrate that disregarding diel variation leads to errors in scaling. We propose that during the MF-DFA of WSTS, the segment length should be longer than 1 day and the diel variation of wind should be maintained to avoid abnormal phenomena and discrepancy in scaling exponents.