Experimental and theoretical insight into carbamazepine degradation by chlorine-based advanced oxidation processes: Efficiency, energy consumption, mechanism and DBPs formation.

Chlorine has been widely used in different advanced oxidation processes (AOPs) for micropollutants removal. In this study, different chlorine-based AOPs, namely medium pressure (MP) UV/chlorine, low pressure (LP) UV/chlorine, and in-situ chlorination, were compared for carbamazepine (CBZ) removal efficiency, energy consumption, and disinfection by-products (DBPs) formation. All three processes could achieve nearly 100% CBZ removal, while the reaction time needed by in-situ chlorination was double the time required by UV/chlorine processes. The energy consumed per magnitude of CBZ removed (EE/O) of MP UV/chlorine was 13 times higher than that of LP UV/chlorine, and relative to that of in-situ chlorination process. Accordingly, MP and LP UV/chlorine processes generated one to two orders of magnitude more hydroxyl radicals (•OH) and reactive chlorine species (RCS) than in-situ chlorination. Besides, RCS were the dominant reactive species, contributing to 78.3%, 75.6%, and 71.6% of CBZ removal in MP, LP UV/chlorine, and in-situ chlorination, respectively. According to the Gibbs free energy barriers between CBZ and RCS/•OH calculated based on density functional theory (DFT), RCS had more reaction routes with CBZ and showed lower energy barrier in the main CBZ degradation pathways like epoxidation and formation of iminostilbene. When applied to secondary wastewater effluent, UV/chlorine and in-situ chlorination produced overall DBPs ranging from 104.77 to 135.41 µg/L. However, the production of chlorate during UV/chlorine processes was 15 times higher than that during in-situ chlorination.

Using immune cell-based bioactivity assays to compare the inflammatory activities of oil sands process-affected waters from a pilot scale demonstration pit lake.

In this study, we provide evidence that oil sands process-affected waters (OSPW) contain factors that activate the antimicrobial and proinflammatory responses of immune cells. Specifically, using the murine macrophage RAW 264.7 cell line, we establish the bioactivity of two different OSPW samples and their isolated fractions. Here, we directly compared the bioactivity of two pilot scale demonstration pit lake (DPL) water samples, which included expressed water from treated tailings (termed the before water capping sample; BWC) as well as an after water capping (AWC) sample consisting of a mixture of expressed water, precipitation, upland runoff, coagulated OSPW and added freshwater. Significant inflammatory (i.e. macrophage activating) bioactivity was associated with the AWC sample and its organic fraction (OF), whereas the BWC sample had reduced bioactivity that was primarily associated with its inorganic fraction (IF). Overall, these results indicate that at non-toxic exposure doses, the RAW 264.7 cell line serves as an acute, sensitive and reliable biosensor for the screening of inflammatory constituents within and among discrete OSPW samples.

Impact of the Chlorination of Lithium Argyrodites on the Electrolyte/Cathode Interface in Solid-State Batteries.

Lithium argyrodite-type electrolytes are regarded as promising electrolytes due to their high ionic conductivity and good processability. Chemical modifications to increase ionic conductivity have already been demonstrated, but the influence of these modifications on interfacial stability remains so far unknown. In this work, we study Li6 PS5 Cl and Li5.5 PS4.5 Cl1.5 to investigate the influence of halogenation on the electrochemical decomposition of the solid electrolyte and the chemical degradation mechanism at the cathode interface in depth. Electrochemical measurements, gas analysis and time-of-flight secondary ion mass spectrometry indicate that the Li5.5 PS4.5 Cl1.5 shows pronounced electrochemical decomposition at lower potentials. The chemical reaction at higher voltages leads to more gaseous degradation products, but a lower fraction of solid oxygenated phosphorous and sulfur species. This in turn leads to a decreased interfacial resistance and thus a higher cell performance.

Interface Design Enabling Stable Polymer/Thiophosphate Electrolyte Separators for Dendrite-Free Lithium Metal Batteries.

Organic/inorganic interfaces greatly affect Li+ transport in composite solid electrolytes (SEs), while SE/electrode interfacial stability plays a critical role in the cycling performance of solid-state batteries (SSBs). However, incomplete understanding of interfacial (in)stability hinders the practical application of composite SEs in SSBs. Herein, chemical degradation between Li6 PS5 Cl (LPSCl) and poly(ethylene glycol) (PEG) is revealed. The high polarity of PEG changes the electronic state and structural bonding of the PS4 3- tetrahedra, thus triggering a series of side reactions. A substituted terminal group of PEG not only stabilizes the inner interfaces but also extends the electrochemical window of the composite SE. Moreover, a LiF-rich layer can effectively prevent side reactions at the Li/SE interface. The results provide insights into the chemical stability of polymer/sulfide composites and demonstrate an interface design to achieve dendrite-free lithium metal batteries.

Enhanced primary treatment during wet weather flow using ferrate as a coagulant, coagulant aid and disinfectant.

This study evaluated the dual-function of ferrate as a coagulant and disinfectant for chemically-enhanced primary treatment during wet weather flow (WWF). For the first time, ferrate was thoroughly examined as a coagulant aid with aluminum sulfate (alum) to minimize the organic and inorganic contents along with microbial level during WWF. Ferrate as a coagulant was evaluated based on a two-level factorial design. At an optimized condition, a ferrate dose of 0.5 mg/L Fe with a cationic polymer (1.25 mg/L) removed 83% of turbidity, 87% of total suspended solids (TSS), 70% of chemical oxygen demand (COD), and 23% of ortho-phosphate (OP). Linear models were developed and used to adequately predict the removals. Ferrate as a coagulant aid added with alum showed better removal of TSS while no improvement was observed in the removals of turbidity and COD. The disinfection capacity of ferrate was evaluated at different dosing points when it was used as a coagulant, coagulant aid and as post dosed as a disinfectant. In particular, ferrate dose of 8 mg/L Fe removed only 2 logs of E. coli when it was used as a coagulant compared to more than 3-log removal of E. coli when ferrate was used as a coagulant aid and as a disinfectant. At optimal ferrate dose of 10 mg/L Fe as a coagulant aid with 6 mg/L Al achieved the target levels of turbidity (<8 NTU), TSS (<25 mg/L), and ferrate-induced iron particles (<0.6 mg/L) along with 5-log removal of E. coli within 31 min. This study suggested that using ferrate as a coagulant aid/disinfectant might be considered an effective approach for treating the wastewater during WWF.

Influences of integrated coagulation-ozonation pretreatment on the characteristics of dissolved organic pollutants (DOPs) of heavy oil electric desalting wastewaters.

The quality of heavy oil electric desalting wastewaters (HO-EDWs) affects the effectiveness of refinery wastewater treatment plants. In this study, an integrated coagulation-ozonation (ICO) process was used to pretreat HO-EDWs and the influences on the characteristics of dissolved organic pollutants (DOPs) were investigated. Coagulation using aluminum sulfate removed 39% of soluble chemical oxygen demand (SCOD), 21% of dissolved organic carbon (DOC), 57% of petroleum hydrocarbons and 38% of polar oils from Liaohe HO-EDWs and the biodegradability was greatly improved. Ozonation removed 33% of SCOD and 88% of polar oils from the coagulated HO-EDWs. Most species of aromatic compounds, phenols, aliphatic acids, anilines and naphthenic acids with high C numbers and ring numbers were degraded and the unsaturation degrees of DOPs significantly decreased under ozonation. As a result, the biodegradability was further improved and the acute toxicity towards Vibrio fischeri was substantially reduced. Some OxS1 species and organic nitrogen compounds in HO-EDWs were penetrated through ozonation and caused the residual biotoxicity. The results demonstrate the potential of ICO pretreatment for improving the quality of refractory HO-EDWs.

Combined antitumor effects of anti-EGFR variant III CAR-T cell therapy and PD-1 checkpoint blockade on glioblastoma in mouse model.

Glioblastoma is one of the deadliest cancers. Chimeric antigen receptor (CAR)-T cell therapy against solid tumors has been far from satisfactory largely due to the immunosuppressive tumor microenvironment, such as PD-1 mediated T cell exhaustion. In the present study, we investigated the combined antitumor effects of anti-EGFR variant III CAR-T cell therapy and PD-1 checkpoint blockade on glioblastoma in mouse model. The results demonstrated that CAR-T cells with PD-1 blockade exhibit higher killing efficiency in vitro. Additionally, CAR-T cells with PD-1 blockade showed more effective and persistent therapeutic effects on glioblastoma and led to significantly increased number of tumor infiltrating lymphocytes (TILs) in the mouse model. In conclusion, PD-1 checkpoint blockade significantly enhanced the antitumor activity of anti-human EGFRvIII CAR-T cells by overcoming TILs exhaustion. The outcomes of the present study provide a novel strategy for improving the potency of CAR-T cell therapies in solid tumors.

Interfacial Evolution of Lithium Dendrites and Their Solid Electrolyte Interphase Shells of Quasi-Solid-State Lithium-Metal Batteries.

Unstable electrode/solid-state electrolyte interfaces and internal lithium dendrite penetration hamper the applications of solid-state lithium-metal batteries (SSLMBs), and the underlying mechanisms are not well understood. Herein, in situ optical microscopy provides insights into the lithium plating/stripping processes in a gel polymer electrolyte and reveals its dynamic evolution. Spherical lithium deposits evolve into moss-like and branch-shaped lithium dendrites with increasing current densities. Remarkably, the on-site-formed solid electrolyte interphase (SEI) shell on the lithium dendrite is distinctly captured after lithium stripping. Inducing an on-site-formed SEI shell with an enhanced modulus to wrap the lithium precipitation densely and uniformly can regulate dendrite-free behaviors. An in-depth understanding of lithium dendrite evolution and its functional SEI shell will aid in the optimization of SSLMBs.

Engineering Janus Interfaces of Ceramic Electrolyte via Distinct Functional Polymers for Stable High-Voltage Li-Metal Batteries.

The fast-ionic-conducting ceramic electrolyte is promising for next-generation high-energy-density Li-metal batteries, yet its application suffers from the high interfacial resistance and poor interfacial stability. In this study, the compatible solid-state electrolyte was designed by coating Li1.4Al0.4Ti1.6(PO4)3 (LATP) with polyacrylonitrile (PAN) and polyethylene oxide (PEO) oppositely to satisfy deliberately the disparate interface demands. Wherein, the upper PAN constructs soft-contact with LiNi0.6Mn0.2Co0.2O2, and the lower PEO protects LATP from being reduced, guaranteeing high-voltage tolerance and improved stability toward Li-metal anode performed in one ceramic. Moreover, the core function of LATP is amplified to guide homogeneous ions distribution and hence suppresses the formation of a space-charge layer across interfaces, uncovered by the COMSOL Multiphysics concentration field simulation. Thus, such a bifunctional modified ceramic electrolyte integrates the respective superiority to render Li-metal batteries with excellent cycling stability (89% after 120 cycles), high Coulombic efficiency (exceeding 99.5% per cycle), and a dendrite-free Li anode at 60 °C, which represents an overall design of ceramic interface engineering for future practical solid battery systems.

Trapping Lithium into Hollow Silica Microspheres with a Carbon Nanotube Core for Dendrite-Free Lithium Metal Anodes.

Li metal anodes, which have attracted much attention for their high specific capacity and low redox potential, face a great challenge in realizing their practical application. The fatal issue of dendrite formation gives rise to internal short circuit and safety hazards and needs to be addressed. Here we propose a rational strategy of trapping Li within microcages to confine the deposition morphology and suppress dendrite growth. Microcages with a carbon nanotube core and porous silica sheath were prepared and proved to be effective for controlling the electrodeposition behavior. In addition, the insulative coating layer prevents concentrated electron flow and decreases the possibility of "hot spots" formation. Because of the Li trapper and uniform electron distribution, the electrode with delicate structure exhibits a dendrite-free morphology after plating 2 mA h cm-2 of Li. As the dendrite growth is suppressed, the as-obtained electrode maintains a high plating/stripping efficiency of 99% over 200 cycles. This work delivers new insights into the design of rational Li metal anodes and hastens the practical application of Li metal batteries.

Nitriding-Interface-Regulated Lithium Plating Enables Flame-Retardant Electrolytes for High-Voltage Lithium Metal Batteries.

Safety concerns are impeding the applications of lithium metal batteries. Flame-retardant electrolytes, such as organic phosphates electrolytes (OPEs), could intrinsically eliminate fire hazards and improve battery safety. However, OPEs show poor compatibility with Li metal though the exact reason has yet to be identified. Here, the lithium plating process in OPEs and Li/OPEs interface chemistry were investigated through ex situ and in situ techniques, and the cause for this incompatibility was revealed to be the highly resistive and inhomogeneous interfaces. Further, a nitriding interface strategy was proposed to ameliorate this issue and a Li metal anode with an improved Li cycling stability (300 h) and dendrite-free morphology is achieved. Meanwhile, the full batteries coupled with nickel-rich cathodes, such as LiNi0.8 Co0.1 Mn0.1 O2 , show excellent cycling stability and outstanding safety (passed the nail penetration test). This successful nitriding-interface strategy paves a new way to handle the incompatibility between electrode and electrolyte.

Guiding Uniform Li Plating/Stripping through Lithium-Aluminum Alloying Medium for Long-Life Li Metal Batteries.

The uncontrolled growth of Li dendrites upon cycling might result in low coulombic efficiency and severe safety hazards. Herein, a lithiophilic binary lithium-aluminum alloy layer, which was generated through an in situ electrochemical process, was utilized to guide the uniform metallic Li nucleation and growth, free from the formation of dendrites. Moreover, the formed LiAl alloy layer can function as a Li reservoir to compensate the irreversible Li loss, enabling long-term stability. The protected Li electrode shows superior cycling over 1700 h in a Li|Li symmetric cell.

An Abnormal 3.7†Volt O3-Type Sodium-Ion Battery Cathode.

Layered O3-type sodium oxides (NaMO2 , M=transition metal) commonly exhibit an O3-P3 phase transition, which occurs at a low redox voltage of about 3 V (vs. Na+ /Na) during sodium extraction and insertion, with the result that almost 50 % of their total capacity lies at this low voltage region, and they possess insufficient energy density as cathode materials for sodium-ion batteries (NIBs). Therefore, development of high-voltage O3-type cathodes remains challenging because it is difficult to raise the phase-transition voltage by reasonable structure modulation. A new example of O3-type sodium insertion materials is presented for use in NIBs. The designed O3-type Na0.7 Ni0.35 Sn0.65 O2 material displays a highest redox potential of 3.7 V (vs. Na+ /Na) among the reported O3-type materials based on the Ni2+ /Ni3+ couple, by virtue of its increased Ni-O bond ionicity through reduced orbital overlap between transition metals and oxygen within the MO2 slabs. This study provides an orbital-level understanding of the operating potentials of the nominal redox couples for O3-NaMO2 cathodes. The strategy described could be used to tailor electrodes for improved performance.

Chlorination of Amino Acids: Reaction Pathways and Reaction Rates.

Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected byproducts. In a detailed investigation, we report rate constants for all reactions in the chlorination of valine, for the first time, using experimental results and modeling. At Cl:AA = 2.8, the chlorine was found to first react quickly with valine (5.4 × 104 M-1 s-1) to form N-monochlorovaline, with a slower subsequent reaction with N-monochlorovaline to form N,N-dichlorovaline (4.9 × 102 M-1 s-1), although some N-monochlorovaline degraded into isobutyraldehyde (1.0 × 10-4 s-1). The N,N-dichlorovaline then competitively degraded into isobutyronitrile (1.3 × 10-4 s-1) and N-chloroisobutyraldimine (1.2 × 10-4 s-1). In conventional drinking water disinfection, N-chloroisobutyraldimine can potentially be formed in concentrations higher than its odor threshold concentration, resulting in aesthetic challenges and an unknown health risk.

Organic chloramines in chlorine-based disinfected water systems: A critical review.

This paper is a critical review of current knowledge of organic chloramines in water systems, including their formation, stability, toxicity, analytical methods for detection, and their impact on drinking water treatment and quality. The term organic chloramines may refer to any halogenated organic compounds measured as part of combined chlorine (the difference between the measured free and total chlorine concentrations), and may include N-chloramines, N-chloramino acids, N-chloraldimines and N-chloramides. Organic chloramines can form when dissolved organic nitrogen or dissolved organic carbon react with either free chlorine or inorganic chloramines. They are potentially harmful to humans and may exist as an intermediate for other disinfection by-products. However, little information is available on the formation or occurrence of organic chloramines in water due to a number of challenges. One of the biggest challenges for the identification and quantification of organic chloramines in water systems is the lack of appropriate analytical methods. In addition, many of the organic chloramines that form during disinfection are unstable, which results in difficulties in sampling and detection. To date research has focussed on the study of organic monochloramines. However, given that breakpoint chlorination is commonly undertaken in water treatment systems, the formation of organic dichloramines should also be considered. Organic chloramines can be formed from many different precursors and pathways. Therefore, studying the occurrence of their precursors in water systems would enable better prediction and management of their formation.

[Effects of Enhanced Ultraviolet B Irradiation on Photosynthetic and Antioxidant System of Sorghum Seedlings].

The UV-B radiation on the surface of our planet has been enhanced due to gradual thinning of ozone layer. The change of solar spectrum UV-B radiation will cause damage to all kinds of terrestrial plants at certain degree. In this paper, taking breeding sorghum (Sorghum bicolor (L.Moench))variety Longza No.5 as sample, 40 µW·cm-2 UV-B radiation treatment was conducted on sorghum seedlings at two-leaf and one-heart stage and different time courses; then after a 2 d recovering, photosynthetic parameters were measured with a photosynthetic apparatus; the activities of antioxidant enzymes were detected as well. Our results revealed that, as the dosages of UV-B increasing, leaf browning injury was aggravated, plants dwarfing and significantly were reduced fresh weight and dry weight were observed; anthocyanin content was significantly increased; chlorophyll and carotenoid content significantly were reduced and net photosynthetic rate and chlorophyll fluorescence parameters were decreased. Meanwhile, with the increase in UV-B dosages, stomatal conductance, intercellular CO2 concentration and transpiration rate showed "down - up - down" trend; the activities of SOD and GR presented "down - up" changes; activities of POD and CAT demonstrated "down - up - down", and APX, GPX showed an "up - down - up" pattern. It is worth to note that, under the four-dose treatment, a sharp decline in net photosynthesis in sorghum seedlings was observed at 6 h UV-B treatment (equals to 2.4 J·m-2), and an obvious turning point was also found for other photosynthetic parameters and activities of antioxidant enzymes at the same time point. In summary, the results indicated that the enhanced UV-B radiation directly accounted for the damages in photosynthesis system including photosynthetic pigment content, net photosynthetic rate and chlorophyll fluorescence parameters of sorghum; the antioxidant system showed different responses to UV-B radiation below or above 6 h treatment: ASA-GSH cycle was more sensitive to low-dose UV-B radiation, while high-dose UV-B radiation not only undermined the photosynthesis system, but also triggered plant enzymatic and non-enzymatic antioxidant systems, resulting in leaf browning and necrosis,biomass accumulation reduction, plant dwarfing and even death.

[Wavefront analysis and comparison between small incision lenticule extraction and femtosecond laser in situ keratomilensis].

OBJECTIVE: To investigate and analyze the characteristic changes of high order aberrations before and after small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK). METHODS: Prospective study. Thirty-four patients (16 men and 18 women) underwent SMILE, and 28 cases (15 men and 13 women) underwent FS-LASIK, aged 18 to 39 years. Only the right eye was selected to be analyzed from each patient. All patients had conventional and Pentacam examinations preoperatively, and the ocular higher order aberrations were measured with the Hartman-Shack wavefront analyzer before surgery and at 1 month and 3 months postoperatively. The paired t test, independent t test, and Pearson correlation analysis were used to analyze the collected data. RESULTS: At the 1 month after SMILE group, C3(-1), C3(3) (-0.205 +/- 0.199, 0.027 +/- 0.071) were higher than the FS-LASIK group (0.004 +/- 0.316, -0.022 +/- 0.104) (t = -3.141, 2.216, P < 0.05), for FS-LASIK group Sh, S4 S5, S6, C4(0) (0.609 +/- 0.199, 0.403 +/- 0.196, 0.117 +/- 0.065, 0.092 +/- 0.038, 0.343 +/- 0.253) were higher than the SMILE group (0.461 +/- 0.130, 0.271 +/- 0.096, 0.074 +/- 0.028, 0.053 +/- 0.018, 0.239 +/- 0.121) (t = - 3.492, -3.461, -3.449, -5.301, -2.103, P < 0.05); At the 3rd month of SMILE group, C3(-1) (-0.177 +/- 0.175) was higher than the FS-LASIK group (-0.012 +/- 0.337) (t = -2.476, P < 0.05), In FS- LASIK group , however, the data for Sh, S4, S5, S6, C4(0) (0.626 +/- 0.215, 0.421 +/- 0.200, 0.108 +/- 0.066, 0.082 +/- 0.036, 0.393 +/- 0.207) were higher than the SMILE group (0.457 +/- 0.113, 0.270 +/- 0.106,0. 082 +/- 0.031, 0.051 +/- 0.017, 0.243 +/- 0.115 ) (t = -3.935, -3.788, -2.049, -4.405, -3.576, P < 0.05). With the correlation analysis, at the postoperative 1st and 3rd month of FS-LASIK group, Sh, C4(0) had negative relationship with the attempted myopic corrections (1 month post-op: r = - 0.433, -0.476, P < 0.05; 3 month post-op:r = -0.418, -0.447, P < 0.05). CONCLUSION: SMILE resulted in good optical quality early after operation. Compared with FS-LASIK, SMILE caused smaller change of ocular higher order aberrations, and each of them had its own particularity. Maybe it was associated with the surgery procedure and corneal wound healing after surgery.

[The study of the changes of ultra- microstructure after a momentary action of femtosecond laser with human corneal tissue in vivo].

OBJECTIVE: To observe the changes of pathology and ultra- microstructure of corneal lenticules extracted by femtosecond laser small incision lenticule extraction surgery and to investigate instantaneous damage of photodisruption of femtosecond laser to human corneal tissue in vivo. METHODS: The small incision lenticule extraction surgeries in 25 myopic eyes were performed with Carl Zeiss VisuMax femtosecond laser, and the lenticules were observed by light microscopy, scanning electron microscopy and transmission electron microscopy. RESULTS: Light microscopy showed slight edema in part of the collagen fibers in the cornea lenticule tissue. A thin layer of deep tissue dyeing at the edge of the lenticule was observed on a linear array. In the center of superficial lenticule tissue existed a few bubbles. Under the scanning electron microscope, the anterior surface of the lenticule was found to be relatively smooth, with no obvious tissue bridge. The posterior surface of the lenticule was slightly irregular compared with the anterior surface. Scattered tissue bridges and residual traces of the effect of femtosecond laser photodisruption could be observed. Under the transmission electron microscope, adjacent collagen fiber layers in the corneal lenticule matrix were detected to cross each other regularly, with no breakage of the collagen fibers or separation of the layers. The incision of the collagen fibers on one side of the lenticule was on a linear alinement. It can also be observed that the central part of the lenticule was mildly damaged. However, the stroma cells near the lenticule limbus were severely damaged. Part of the corneal stroma cells were solidified with several shivers, which might be due to the photodisruption. Some of the damaged corneal stroma cells were observed with remnants, while the spaces occupied by part of the corneal cells became fractured. CONCLUSIONS: Obvious damage of the femtosecond laser to the corneal tissue at early stage was not observed. At the edge of the area where femtosecond laser focused, there were mild thermal injury and slight structure change. There were not abnormal appearances of the tissue structure at the non-focus area.

[Two millimeter micro incision lenticule extraction surgery with minimal invasion: a preliminary clinical report].

OBJECTIVE: To report the clinical results of micro incision lenticule extraction (MILE) to correct myopia or myopia with astigmatism, and enlighten its viability and mechanism. METHODS: Prospective case-control study. All patients enrolled were treated by the VisuMax femtosecond laser system to correct refractive errors. Sixty-one patients underwent MILE with an incision of 2 mm. Another 53 patients underwent small incision lenticule extraction (SMILE) with a 3-5 mm incision as the control group. All patients took measurements of uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refractive power and intraocular pressure, slit-lamp microscopy, and corneal topography preoperatively and at 1 day, 1 week, 1 month, 6 months postoperatively. The visual acuity was presented as median. To compare the visual acuity and astigmatism between the MILE group and the SMILE group, as well as before surgery and at each time point after surgery, non-parametric tests were applied in this study. The repeated measures analysis of variance was used to compare the differences between these two surgeries and between pre- and post-operation in diopters and morphological parameters. The paired-sample t test was used to compare the diopters and morphological parameters at each time point postoperatively and preoperatively. The independent-sample t test was applied to compare the basic characteristics preoperatively and the diopters, morphological parameters at each time point between these two groups. RESULTS: Forty-one eyes (24 patients) in the MILE group and fifty-one eyes (29 patients) in the SMILE group had complete follow-up data. Before surgery and at 1 day, 1 week, 1 month, 6 months after surgery, the spherical diopters in the MILE group were (-5.09 ± 1.04), (0.12 ± 0.32), (0.11 ± 0.29), (0.02 ± 0.33) and (0.02 ± 0.23) D; the cylinder diopters were (-0.90 ± 0.83), (-0.25 ± 0.27), (-0.23 ± 0.30), (-0.20 ± 0.25) and (-0.16 ± 0.21) D. In the SMILE group, the spherical diopters were (-5.37 ± 1.26), (-0.04 ± 0.49), (0.12 ± 0.38), (0.10 ± 0.34) and (0.02 ± 0.33) D; the cylinder diopters were (-0.76 ± 0.65), (-0.22 ± 0.26), (-0.25 ± 0.30), (-0.26 ± 0.29) and (-0.21 ± 0.28) D. No significant difference was found between the two groups (F = 1.042, 0.941, 0.018; P = 0.310, 0.335, 0.894). In the vector analysis of astigmatism, at 1 month and 6 months after surgery, the values on Y axis were -0.06 ± 0.11 and -0.04 ± 0.10 in the MILE group, smaller than -0.14 ± 0.18 and -0.11 ± 0.16 in the SMILE group (Z = -2.076, -2.149; P = 0.038, 0.032). All full-correction patients had UCVA of 20/20 or better, and no BCVA decreased after 6 month follow-up postoperatively. Refractive stability was achieved within 1 month postoperatively, and less volatility appeared in the MILE group than the SMILE group. Before surgery and at 1 day, 1 week, 1 month, 6 months after surgery, no significant difference in the index of surface variance (ISV) and the index of vertical asymmetry (IVA) was found between the MILE group and the SMILE group (F = 0.902, 0.744; P = 0.345, 0.391), whereas the values of ISV and IVA were smaller in the MILE group than the SMILE group at each time point after surgery, and the D-value between the two groups increased with time. Six cases (9 eyes) had an opaque bubble layer while femtosecond laser passed in the procedure, 2 eyes had a small tear at the incision edge, 1 eye had local diffuse inflammatory exudates at 1 day postoperatively, and no eye had transient light-sensitivity syndrome, decrease of corneal transparency or infection. CONCLUSIONS: MILE surgery (1.5-2.0 mm) is safe, predictable, effective and stable to treat refractive errors. It can reduce astigmatism values on oblique axis and maintain the integrality and stability of the structure of the cornea.

Ocular higher-order aberration features 10 years after photorefractive keratectomy.

The aim of the present study is to re-evaluate the original cohort of patients who participated in the first photorefractive keratectomy (PRK) trial in the 1990s, especially their optical performance. Forty-four eyes (24 patients) of the original cohort who underwent PRK using the NIDK EC-5000 excimer laser platform returned 10 years (range 9-14 years) postoperatively to have higher-order aberrations (HOAs) recorded. Wavefront aberrations were measured using Wavescan (VISX, Santa Clara, CA, USA) and calculated for 3- and 6-mm pupil size. The total RMS (the square root of the sum of squared Zernike coefficients) of higher-order wavefront error (3rd-6th radial order) and the Zernike coefficients, as well as the third-order (S 3) and fourth-order (S 4) aberrations, spherical aberrations and coma aberration values were analyzed. An independent sample t test was used for comparisons and a P value <0.05 was considered statistically significant. The mean RMS of higher-order wavefront values showed an increase but no significant difference in postoperative eyes compared to the control-matched normal level with the 6-mm pupil (HOA RMS: control group 0.31 ± 0.12 µm; 10-year post-PRK group 0.56 ± 0.15 µm; P = 0.141). The main contribution was the increase of spherical aberrations (Z 12) and spherical-like aberrations (S 4), which increased by fourfold and 2.5-fold, respectively, in the 10-year post-PRK group (control group Z 12 0.08 ± 0.11 µm, S 4 0.14 ± 0.05 µm; 10-year post-PRK group Z 12 0.35 ± 0.15 µm, S 4 0.37 ± 0.14 µm; P = 0.010*). Most increases of ocular HOAs induced by corneal refractive surgery are becoming extremely minor at 10 years postoperatively, closer to the corresponding preoperative amount. The largest increase was spherical and spherical-like aberrations, especially with a larger pupil size.