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To address the issue of low viscosity and poor high-temperature shear resistance of suspension liquid type fracturing fluids commonly used in continuous fracturing operations for high-temperature unconventional oil reservoirs with large displacement mineralized water, A novel titanium crosslinking agent has been prepared, which can significantly enhances the temperature resistance and shear resistance of the gel. In addition, a novel dialysis purification method is proposed, which allows the titanium crosslinker to be pre-mixed with anhydrous suspension, and overcomes the defect of uneven mixing due to high viscosity fluid when add crosslinker, which can't be solved by boron or zirconium crosslinker. Here, the crosslinking agent was prepared by mixing butyl titanate, lactic acid, triethanolamine and water according to a certain molar ratio. Then, the resulting gel was obtained by pre-mixing with suspension fracturing fluid liquid, and can maintain the viscosity of 63.1mPa·s at a shear rate of 170 s−1 and 150 °C, which is nearly twice that of the gel to bring with added externally crosslinking agents. The fracturing fluid can effectively increase fracturing efficiency, and has excellent application prospects in the context of High temperature deep well and large displacement fracturing. [ABSTRACT FROM AUTHOR]

The control of emerging tetracycline organic pollutants in aquatic environments has been a recent challenge and research focus in the field of water pollution. This study presents a sol–gel method for synthesizing copper-titanium bimetallic doped silica microspheres as an effective adsorbent for removing tetracycline from aqueous solutions. The microspheres were characterized using SEM, TEM, FT-IR, XPS, and BET analysis, and the effects of pH, dosage, time, and ion strength on tetracycline adsorption were investigated. The maximum adsorption capacity of the material was found to be 99.96 mg/g, significantly higher than monometallic doped microspheres. The enhanced adsorption properties for tetracycline are a result of the larger specific surface area (421.49 m2 g−1), pore size (14.7819 nm), and new metal coordination sites of the copper-doped material. Kinetic and isotherm modeling confirmed the effectiveness of the adsorbent, and FT-IR and XPS analyses suggested hydrogen bonding and copper complex formation as the primary mechanisms for tetracycline adsorption. At the fifth reuse, it is still possible to achieve 60% removal rate. All the results suggest that Cu/Ti-SiO2 composites can be a promising material for the removal of tetracycline from wastewater. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the characteristics, potential risk factors and associated severity of keratoconus on the east coast of China. Methods: In this case–control study, patients diagnosed with keratoconus were invited to fill in the online electronic questionnaire designed with the help of the App named WenJuanXing. Several questions like, sex, age of diagnosis and eye care habits were administered to each subject through this e-questionnaire. Corneal topographies at diagnosis taken from Pentacam were also collected. Results: Totally 391 Chinese keratoconus outpatients were enrolled in this study, among which 159 patients were newly diagnosed. Only three patients (0.77%) had a positive family history of keratoconus. Atopy could be identified in 66.0% of our patients. A total of 357 patients (91.3%) mentioned the habit of eye rubbing, with 191 patients (48.8%) rubbing their eyes frequently. Patients with younger age at onset (p = 0.005), male sex (p = 0.042), frequent eye rubbing (p = 0.003) and smoke (p = 0.002) were found significantly associated with increased risk of acute hydrops. In newly diagnosed patients, 79.9% had the maximum keratometry (Kmax) more than 52D, with males and patients aged 21–30 being even more serious (p = 0.009; p = 0.005). Besides, in patients aged over 21, frequent eye rubbing was significantly associated with steeper Kmax and more severe astigmatism (all p < 0.05). Conclusion: Our results suggest that frequent eye rubbing is closely related to the severity of keratoconus in Chinese patients. Chinese keratoconus patients always had much serious disease condition at the time of diagnosis. Thus, increasing the publicity of keratoconus and advocating appropriate eye care habits are needed urgently in China. Registration: The research was retrospectively registered, and the trial registration number is ChiCTR1900021273, and the registration date is 2019/02/09. [ABSTRACT FROM AUTHOR]

This study aims to investigate the reliability and efficacy of rear 4-min Schirmer test, as a supplement indicator, in assessing tear secretion and diagnosing dry eye. 180 participants were enrolled in this study. Schirmer test I without anaesthesia was performed once on both eyes to determine the value of normal Schirmer test. The values of tear secretion were recorded at each minute. Other examinations included the following: the ocular surface disease index (OSDI), the standard patient evaluation of eye dryness (SPEED), fluorescein stain, tear film break-up time (BUT), and Meibomian gland (MG) secretion grading. The participants were divided into dry eye (DE) group and non-dry eye (ND) group. The values of the 2-min Schirmer test, rear 3-min Schirmer test, rear 4-min Schirmer test, and 5-min Schirmer test were 5.36 ± 4.63, 5.57 ± 2.11, 7.21 ± 4.13, and 10.93 ± 6.30, respectively, in the DE group. These indicators were 8.25 ± 6.80, 2.73 ± 2.31, 7.36 ± 3.42, and 11.84 ± 6.16, respectively, in the ND group. The rear 4-min Schirmer test had a significant correlation with OSDI and SPEED in the DE group (r = − 0.242/ − 0.183) and in the ND group (r = − 0.316/ − 0.373). Meanwhile, the rear 4-min Schirmer test had a stronger connection with fBUT (r = 0.159) and MG secretion (r = − 0.162) in the DE group and also had higher accuracy in diagnosing severe DE and borderline DE. In conclusion, the rear 4-min Schirmer test may be a supplement indicator in assessing tear secretion and diagnosing DE. [ABSTRACT FROM AUTHOR]

This study aims to investigate the reliability and efficacy of maximum fluorescein tear break-up time (FTBUTmax) in diagnosing dry eye disease (DED). 147 participants were enrolled in this study. Ocular symptoms were assessed by Ocular Surface Disease Index (OSDI). The fluorescein tear break-up time (FTBUT) examination, corneal fluorescein staining (CFS), and Schirmer I test were performed on both eyes. Each participant underwent 3 consecutive FTBUT tests, and five types of FTBUT values including FTBUTmax, the minimum FTBUT (FTBUTmin), the first FTBUT (FTBUT1), the average of three FTBUTs (FTBUT123) and the average of the first and second FTBUT (FTBUT12) were recorded. FTBUTmax was larger than the other FTBUT values, but no differences were found among the values of FTBUT1, FTBUT123, FTBUT12 and FTBUTmin. In the ROC analysis, FTBUTmax had the largest or the second largest area under the ROC (AUROC) in all three DED diagnostic criteria, while FTBUTmin had the least AUROC of them. ROC efficacy of FTBUTmax was significantly higher than that of FTBUT123, FTBUT12, FTBUT1 and FTBUTmin in the OSDI criteria and higher than that of FTBUT1 and FTBUTmin in Schirmer I test and CFS tests. FTBUTmax has a close correlation with OSDI, Schirmer I test and CFS, and is an effective tool for the DED diagnosis. [ABSTRACT FROM AUTHOR]

To evaluate the effectiveness and safety of low-temperature plasma radiofrequency ablation (coblation) and Nd:YAG laser in treating recurrent nasolacrimal duct obstruction. A prospective study was performed on patients who agreed to be treated with coblation or Nd:YAG laser for recurrent nasolacrimal duct obstruction after failed lacrimal Nd:YAG laser combined with silicone intubation. The visual analogue scale (VAS) pain grade was assessed at baseline, immediately, and 3 and 7 days after surgery. The degree of watering, lacrimal passage irrigation, and complications were also evaluated 1 week and 1, 3, and 6 months after surgery. Ninety-five patients who met the criteria for recurrent nasolacrimal duct obstruction from February 2018 to February 2019 were included in this study, with 46 patients receiving coblation and 49 patients Nd:YAG laser. The intraoperative and postoperative (3 days after surgery) VAS pain grades of the patients who received coblation were significantly lower than those who received Nd:YAG laser (P < 0.001). The number of patients in the coblation group who achieved complete clinical relief (no epiphora symptoms with fluent lacrimal passage irrigation) was significantly larger than that in the lacrimal Nd:YAG laser group at 1, 3, and 6 months after surgery (P = 0.033, P = 0.006, P = 0.003, respectively). During the follow-up period, there were no unexpected complications in either group. Compared with Nd:YAG laser, coblation performed well in alleviating pain and maintaining sustained disease relief and may therefore be an alternative to conventional laser or dacryocystorhinostomy surgery in the management of recurrent nasolacrimal duct obstruction. [ABSTRACT FROM AUTHOR]