Enhancing nitrogen removal performance using immobilized aerobic denitrifying bacteria by modified polyvinyl alcohol/sodium alginate (PVA/SA).

Aerobic denitrification has emerged as a promising and efficient method for nitrogen removal from wastewater. However, the direct application of aerobic denitrifying bacteria has faced challenges such as low nitrogen removal efficiency, bacterial loss, and poor stability. To address these issues, this study developed a novel microbial particle carrier using NaHCO3-modified polyvinyl alcohol (PVA)/sodium alginate (SA) gel (NaHCO3-PVA/SA). This carrier exhibits several advantageous properties, including excellent mass transfer efficiency, favorable biocompatibility, convenient film formation, abundant biomass, and exceptional pollutant treatment capacity. The carrier was modified with 0.3% NaHCO3, 8.0% PVA, and 1.0% SA, resulting in a remarkable 3.4-fold increase in the average pore diameter and a 12.8% improvement in mass transfer efficiency. This carrier was utilized to immobilize the aerobic denitrifying bacterium Stutzerimonas stutzeri W-2 to enhance nitrogen removal (NaHCO3-PVA/SA@W-2), resulting in a NO3--N removal efficiency of 99.06%, which was 21.39% higher than that without modification. Compared with the non-immobilized W-2, the degradation efficiency was improved by 43.70%. After five reuses, the NO3--N and TN removal rates remained at 99% and 93.01%, respectively. These results provide a solid foundation for the industrial application of the modified carrier as an effective tool for nitrogen removal in large-scale wastewater treatment processes.

The individual difference of motor imagery ability evoked by visual stimulus and its personality manifestation.

Motor imagery has been commonly studied as a means of motor rehabilitation but, the individual differences limit its practical application. Visually evoked motor imagery has been widely highlighted by researchers because of its vivid stimulus. However, this modality is still not applicable to all persons. In this study, we studied the different performances of the visually evoked motor imagery between subjects and tried to explore the personality manifestation which can result in this performance. We found that conscientiousness and openness have negative connections with the performance of visually evoked motor imagery. To compare with spontaneous motor imagery, the visually evoked motor imagery reflects less personality difference between subjects with good and bad performances on motor imagery. This indicate that visually stimulus may increase the pervasive application of motor imagery. This study may provide benefits to predict the rehabilitation effect and to rapidly select the suitable motor rehabilitation methods.

Responses of straw foam-based aerobic granular sludge to atrazine: Insights from metagenomics and microbial community variations.

Atrazine (ATZ) has caused serious environmental pollution, but the biodegradation of ATZ is relatively slow and inefficient. Herein, a straw foam-based aerobic granular sludge (SF-AGS) was developed, the spatially ordered architectures of which could greatly improve the drug tolerance and biodegradation efficiency of ATZ. The results showed that, in the presence of ATZ, chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), total phosphorus (TP), and total nitrogen (TN) were effectively removed within 6 h, and the removal efficiencies were as high as 93.37%, 85.33%, 84.7%, and 70%, respectively. Furthermore, ATZ stimulated microbial consortia to secrete three times more extracellular polymers compared to without ATZ. Illumina MiSeq sequencing results showed that bacterial diversity and richness decreased, leading to significant changes in microbial population structure and composition. ATZ-resistant bacteria including Proteobacteria, Actinobacteria, and Burkholderia laid the biological basis for the stability of aerobic particles, efficient removal of pollutants, and degradation of ATZ. The study demonstrated that SF-AGS is feasible for ATZ-laden low-strength wastewater treatment.

The EEG Oscillations and Psychology Propensities of Autonomous Sensory Meridian Response.

Autonomous sensory meridian response is believed as a perceptual phenomenon to specific sensory stimuli. To explore the underlying mechanism and emotional effect, the EEG under video and audio triggers of autonomous sensory meridian response was analyzed. The differential entropy and power spectral density by Burg method on δ, θ, α, ß, γ and high γ frequencies were employed as quantitative features. The results indicate that the modulation of autonomous sensory meridian response on brain activities is broadband. Video trigger owns better performance of autonomous sensory meridian response than other triggers. Moreover, the results also reveal that autonomous sensory meridian response has a close relationship with neuroticism and its three sub-dimensions, anxiety, self-consciousness and vulnerability, with the scores of self-rating depression scale, but without emotions, happiness, sadness, or fear. This suggests that the responders of autonomous sensory meridian response may have the tendencies of neuroticism and depressive disorder.

Insights into nitrogen and phosphorus metabolic mechanisms of algal-bacterial aerobic granular sludge via metagenomics: Performance, microbial community and functional genes.

Aiming to propose the potential mechanism for the enhancement of nitrogen (N) and phosphorus (P) removal of algal-bacterial aerobic granular sludge (A-AGS), metagenomic analysis was applied to identify the metabolic pathways. The results showed that chemical oxygen demand, ammonia nitrogen, total N, and total P removal of A-AGS could reach to 94.5%, 97.5%, 78.1%, and 88.5%, respectively. Algae enriched the content of extracellular polymeric substance, which significantly promoted the formation of A-AGS. Further investigations in functional genes suggested that nitrification process (amo, nxr, hao, etc.), denitrification process (nir, nap, nor, etc.), and polyphosphate accumulation (ppk, ppk2, etc.) were enhanced greatly in A-AGS. Notably, genus Thauera was the dominant source of functional genes, which penetrated both in N and P metabolism. The higher N and P removal performance in A-AGS could be attributed to synergistic effect between bacteria and microalgae, which may provide the basic for the application in wastewater treatment.

Diagnostic value of corneal higher-order aberrations in keratoconic eyes.

PURPOSE: This study aimed to investigate the diagnostic value of corneal anterior, posterior, and total higher-order aberrations in keratoconic eyes. METHODS: We enrolled 94 patients (152 eyes) with mild keratoconus (Group 1), 64 patients (101 eyes) with moderate keratoconus (Group 2), and 32 patients (52 eyes) with advanced keratoconus (Group 3) according to the Amsler-Krumeich classification system; 99 healthy controls (197 normal eyes) were likewise enrolled. Anterior, posterior, and total corneal higher-order aberrations were assessed using a rotating Scheimpflug camera. The 3rd-order and 4th-order root-mean-square values were calculated for higher-order aberrations, including coma, spherical, and trefoil aberrations. Differences between keratoconic and normal eyes were analyzed using Kruskal-Wallis tests. Receiver operating characteristic curves were evaluated for the keratoconus and control groups. RESULTS: The differences in coma 90, coma, trefoil, and spherical aberrations, as well as 3rd-order and 4th-order root-mean-square values, were statistically significant between the keratoconus and control groups for all anterior, posterior, and corneal aberrations. The absolute values of these higher-order aberrations were higher in the keratoconus groups than in the control group and increased with keratoconus severity in Groups 1-3. Coma and 3rd-order RMS values showed excellent sensitivity and specificity for discriminating between normal and keratoconus eyes for all anterior, posterior, and corneal aberrations. CONCLUSION: Coma aberrations and 3rd-order root-mean-square values may be valuable for diagnosing keratoconus. Combining these data with topography information may enable the effective and efficient detection of keratoconus in the future.

Preparation and Performance Characterization of Exploding Foil Initiator Based on ODPA-ODA Polyimide Flyer.

The exploding foil initiator (EFI) system has been extensively used in ignition and detonation sequences and proved to be of high safety and reliability. Polyimide is considered the ideal flyer material for EFI due to its excellent performance, including thermal stability, outstanding mechanical properties, high radiation resistance, and excellent dielectric properties. In this study, we prepared the EFI based on a polyimide (ODPA-ODA) flyer, which is spin-coated and solidified on patterned copper film in situ. The electric explosion test shows that the prepared EFI has good working performance, and the 4000 V working voltage drove the flyer to reach a maximum velocity of 5096 m/s. The polyimide morphology and chemical structure after the electric explosion was observed by microscope, SEM, XPS, and FTIR, which showed that the polyimide flyer underwent thermal deformation and complex chemical reactions during an electric explosion. A large number of polyimide bonds broke to form new carbonyl compounds, and the opening of aromatic rings was accompanied by the formation of aliphatic hydrocarbon chains. The morphology and chemical structure analysis after the electric explosion test will lay a foundation for us to further understand the working principle and evolution process of polyimide (ODPA-ODA) flyer.

Artificially constructing mixed bacteria system for bioaugmentation of nitrogen removal from saline wastewater at low temperature.

To alleviate the inhibition effects of multi-stresses, a multi-bacterial bioaugmentation based on stimulating cell-to-cell interactions was applied to improve the stress potential of salt-tolerant aerobic granular sludge (AGS). Results showed that the consortium formed by a combination of salt-tolerant ammonia-nitrogen utilizing bacteria, salt-tolerant nitrite-nitrogen utilizing bacteria and salt-tolerant nitrate-nitrogen utilizing bacteria with a whole biomass ratio of 1:2:1 achieved maximum nitrogen consumption rate (µNH4+-N, µNO2--N and µNO3--N of 1.03, 0.57 and 11.62 mgN/L·h, respectively) at 35 gNaCl/L salinity and 15 °C. The flocculent consortium was aggregated by Aspergillus tubingensis mycelium pellet, which was made into a compound bacterial agent (CBA), and the comprehensive nitrogen consumption capability of CBA was further improved to 2.47-4.36-fold of single functional bacteria. 5% CBA (m/m) was introduced into the seafood processing wastewater in batches, in winter (12-16 °C), the removal efficiencies of NH4+-N and total nitrogen increased from 66.89% to 52.77% of native AGS system to 79.02% and 69.97% of nascent bioaugmentation system, respectively. The analysis of key enzyme activities demonstrated that the ammonia monooxygenase and nitrate reductase activities of the bioaugmentation system were increased to 2.73-folds and 1.94-folds those of the native system. Moreover, due to an increase of 6.18 mg/gVSS and 0.11 in the secreted exopolysaccharide and tightly-bound/total extracellular polymeric substances, respectively, bioaugmentation boosted the cell bioflocculation ability by 13.53%, which enhanced the robustness. This work provided a detailed and feasible technical proposal for enhancing the biological treatment performance of saline wastewater in cold regions.

Apparent diffusion coefficient histogram analysis for differentiating solid ovarian tumors.

Objective: To evaluate the utility of apparent diffusion coefficient (ADC) histogram analysis to differentiate between three types of solid ovarian tumors: granulosa cell tumors (GCTs) of the ovary, ovarian fibromas, and high-grade serous ovarian carcinomas (HGSOCs). Methods: The medical records of 11 patients with GCTs of the ovary (regions of interest [ROI-cs], 137), 61 patients with ovarian fibromas (ROI-cs, 161), and 14 patients with HGSOCs (ROI-cs, 113) confirmed at surgery and histology who underwent diffusion-weighted imaging were retrospectively reviewed. Histogram parameters of ADC maps (ADCmean, ADCmax, ADCmin) were estimated and compared using the Kruskal-WallisH test and Mann-Whitney U test. The area under the curve of receiver operating characteristic curves was used to assess the diagnostic performance of ADC parameters for solid ovarian tumors. Results: There were significant differences in ADCmean, ADCmax and ADCmin values between GCTs of the ovary, ovarian fibromas, and HGSOCs. The cutoff ADCmean value for differentiating a GCT of the ovary from an ovarian fibroma was 0.95×10-3 mm2/s, for differentiating a GCT of the ovary from an HGSOC was 0.69×10-3 mm2/s, and for differentiating an ovarian fibroma from an HGSOC was 1.24×10-3 mm2/s. Conclusion: ADCmean derived from ADC histogram analysis provided quantitative information that allowed accurate differentiation of GCTs of the ovary, ovarian fibromas, and HGSOCs before surgery.

Downregulation of hsa_circ_0000885 suppressed osteosarcoma metastasis and progression via regulating E2F3 expression and sponging miR-16-5p.

Introduction: Accumulating evidence has shown that circular RNAs (circRNAs) have indispensable functions during tumor progression by regulating gene expression. A previous study found that upregulation of hsa_circ_0000885 indicated a poor clinical outcome of osteosarcoma (OS). However, the regulatory mechanism of this process is unclear. Methods: This investigation aimed to elucidate how hsa_circ_0000885 regulated OSs. The study used RT-qPCR to investigate hsa_circ_0000885 expression in OS cells. We conducted luciferase reporter assays and analyses to confirm the hsa_circ_0000885 downstream target. We transfected OS cells using different vectors and used Transwell migration, colony formation, western blotting, Matrigel invasion, proliferation, in vivo tumorigenesis, and metastasis assays to identify the role of hsa_circ_0000885 in OS. Results: The results showed that hsa_circ_0000885 expression altered OS cell lines, and that hsa_circ_0000885 downregulation suppressed OS cell proliferation and invasion using in vivo and in vitro experiments. Luciferase reporter assays verified that miR-16-5p and E2F3 were downstream targets of hsa_circ_0000885. E2F3 overexpression or miR-16-5p inhibition reversed OS cell invasion and proliferation after silencing hsa_circ_0000885. Furthermore, hsa_circ_0000885 affected cancer stem cell differentiation by regulating miR-16-5p/E2F3. Conclusions: Overall, the results showed that hsa_circ_0000885 downregulation suppressed OS progression and metastasis via regulating E2F3 expression and sponging miR-16-5p.

The utility of diffusion-weighted imaging and ADC values in the characterization of mumps orchitis and seminoma.

BACKGROUND: Diffusion-weighted imaging (DWI) can quantitatively reflect the diffusion characteristics of tissues, providing a theoretical basis for qualitative diagnosis and quantitative analysis of a disease. PURPOSE: To characterize testicular lesions that present as a hypointense signal on magnetic resonance imaging (MRI) T2-weighted images using DWI. MATERIAL AND METHODS: Study participants were divided into three groups. Group A were healthy controls (n = 35), group B included patients with mumps orchitis (n = 20), and group C included patients with seminoma (n = 15). DWI sequences used b-values of 0, 1000, and 2000 s/mm2. Apparent diffusion coefficient (ADC) values between 1000 and 2000 s/mm2 were calculated by MRI postprocessing software. The Kruskal-Wallis test and receiver operating characteristic analysis were performed to evaluate how well ADC values distinguished between mumps orchitis and seminoma. RESULTS: Normal testicular tissue showed a hyperintense signal on DWI and hypointensity on the ADC map: mean ADC value was 0.77 (0.69-0.85) ± 0.08 ×10-3 mm2/s. Mumps orchitis and seminoma showed slight hyperintensity on DWI: mean ADC values were 0.85 (0.71-0.99) ± 0.15 ×10-3 mm2/s and 0.43 (0.39-0.47) ± 0.04 × 10-3 mm2/s, respectively. There were statistically significant differences in mean ADC values between normal testicular tissue and seminoma and between mumps orchitis and seminoma. The cutoff ADC value for differentiating seminoma from mumps orchitis was 0.54 × 10-3 mm2/s. The sensitivity, specificity, and Youden Index for diagnosing seminoma were 99%, 31%, and 30%, respectively. CONCLUSION: High b-value DWI has potential utility for differentiating mumps orchitis from seminoma in the clinical setting.

All-Cold Evaporation under One Sun with Zero Energy Loss by Using a Heatsink Inspired Solar Evaporator.

Interfacial solar steam generation is a highly efficient and sustainable technology for clean water production and wastewater treatment. Although great progress has been achieved in improving evaporation rate and energy efficiency, it's still challenging to fully eliminate the energy loss to the surrounding environment during solar steam generation. To achieve this, a novel heatsink-like evaporator (HSE) is developed herein. During solar evaporation, the temperature on the top solar evaporation surface can be regulated by the fin structures of the HSE. For the evaporators with 5 to 7 heatsink fins, the temperature of the solar evaporation surface is decreased to be lower than the ambient temperature, which fully eliminates the radiation, convection, and conduction heat losses, leading to the absolute cold evaporation over the entire evaporator under 1.0 sun irradiation. As a result, massive energy (4.26 W), which is over 170% of the received light energy, is harvested from the environment due to the temperature deficit, significantly enhancing the energy efficiency of solar steam generation. An extremely high evaporation rate of 4.10 kg m-2 h-1 is realized with a 6-fin photothermal HSE, corresponding to an energy conversion efficiency far beyond the theoretical limit, assuming 100% light-to-vapor energy conversion.

miR-4319 inhibited retinoblastoma cells proliferation, migration, invasion and EMT progress via suppressing CD147 mediated MMPs expression.

Tumor migration is the critical step that lead to the migration in retinoblastoma (RB), in which microRNAs (miRNAs) play important roles. This study aimed to investigate the role of microRNA-4319 (miR-4319) in the development of retinoblastoma by identifying its targets, as well as its underlying regulatory mechanisms. Our data shown that miR-4319 was downregulated in RB tissues and RB cell lines. Enhanced miR-4319 suppressed cell proliferation, migration, invasion and EMT progress, promoted cell apoptosis in SO-RB50 and RB-Y79 cells. Of note, extracellular matrix metalloproteinase inducer (EMMPRI/CD147) was identified as a direct target gene for miR-4319. MMPs were regulated by CD147 and participated in the miR-4319 regulatory network in SO-RB50 cells. In addition, overexpression of CD147 abrogated the inhibitory effect of miR-4319 on RB cells. In summary, miR-4319 overexpression suppressed cell proliferation, migration and invasion may through suppressing the CD147 mediated MMPs expression, suggesting that miR-4319 may serve as a potential diagnostic biomarker and treatment target for RB.

Apparent diffusion coefficient values of cryptorchid testes and malignant transformation of cryptorchidism (MTC) (seminoma) in postpubertal patients.

OBJECTIVES: Diffusion-weighted imaging signal contrast can be quantified by apparent diffusion coefficient (ADC) maps, which reflect the diffusion properties of the examined tissue and are helpful for identifying pathology. To determine ADC values of cryptorchid testes in post-pubertal patients and assess performance for characterizing cryptorchid testes. METHODS: The medical records from 35 patients with unilateral scrotal vacuity were retrospectively reviewed. Data were analyzed in three groups: Group A, normal testes (i.e. the contralateral testes of the patients with cryptorchidism or MTC); Group B, cryptorchid testes; and Group C, malignant transformation of cryptorchidism (MTC) (seminoma). DWI used b-values of 0 and 800 s/mm2. Mean ADC values were compared using the independent samples t-test. The ability of ADC values was assessed using receiver operating characteristic curve analysis. The sensitivity, specificity, and accuracy were calculated. RESULTS: Mean ADC values for normal testes, cryptorchid testes, and MTC were 1.18 ± 0.18×10-3 mm2/s, 1.82 ± 0.40×10-3 mm2/s, and 0.80 ± 0.06×10-3 mm2/s, respectively. There were statistically significant differences in mean ADC values between normal testes and cryptorchid testes or MTC (p < 0.001). The cut-off ADC value for differentiating normal testes from cryptorchid testes was 1.47 × 10-3 mm2/s. The sensitivity, specificity, and accuracy were 88%, 91%, and 90%, respectively. The cut-off ADC value for differentiating normal testes from MTC was 1.22 × 10-3 mm2/s. The sensitivity, specificity, and accuracy were 100%, 31%, and 43%, respectively. CONCLUSION: ADC values of cryptorchid testes may be used to inform clinical decision-making and also monitor testicular function in patients who retain undescended testicles or post-operatively. ADVANCES IN KNOWLEDGE: Mean ADC values of cryptorchidism and MTC (seminoma) were used to reflect their pathological features.

MRI evaluation of pulmonary lesions and lung tissue changes induced by tuberculosis.

OBJECTIVE: To evaluate the utility of magnetic resonance imaging (MRI) with an advanced motion correction technique in characterizing lung tissue changes and lesions induced by pulmonary tuberculosis (TB). METHODS: Sixty-three subjects with computed tomography (CT) features of pulmonary TB underwent lung MRI. All subjects with pulmonary TB were confirmed by acid-fast bacillus (AFB) testing or the detection of Mycobacterium tuberculosis. T2-weighted turbo spin echo (TSE) sequence MRI with the MultiVane motion correction technique was used to image the lungs. Routine lung CT images were obtained as reference. MRI and CT images were reviewed by multiple readers independently. The performance of MRI in depicting abnormalities induced by pulmonary TB and their morphological changes were evaluated and compared with the performance of CT. RESULTS: Lung MRI found pulmonary abnormalities in all 63 TB subjects, with satisfactory quality. With the implementation of MultiVane for T2-weighted TSE sequences to reduce the motion correction effect, MRI showed excellent agreement with CT in detecting abnormal imaging features of pulmonary TB (κ=0.88, p<0.001), such as tree-in-bud sign, ground-glass opacity, consolidation, mass, and cavitation. MRI was advantageous in identifying caseation and liquefactive necrosis based on inhomogeneous signal distribution within consolidations and also in identifying mild pleural effusion. The optimized lung MRI was comparable to CT in detecting non-calcified nodules (κ=0.90), with overall sensitivity of 50.0%, 91.1%, and 100% for nodules of size <5 mm, 5-10 mm, and >10 mm, respectively. However, MRI was less effective in identifying lesions with calcification. CONCLUSIONS: The clinical implementation of an optimized MRI protocol with the MultiVane motion correction technique for imaging pulmonary TB is feasible. Lung MRI without ionizing radiation is a promising alternative to the clinical standard CT, especially for pregnant women, children, adolescents, and patients requiring short-term and repeated follow-up observations.

White and grey matter development in utero assessed using motion-corrected diffusion tensor imaging and its comparison to ex utero measures.

OBJECTIVE: Fetal brain diffusion tensor imaging (DTI) offers quantitative analysis of the developing brain. The objective was to 1) quantify DTI measures across gestation in a cohort of fetuses without brain abnormalities using full retrospective correction for fetal head motion 2) compare results obtained in utero to those in preterm infants. MATERIALS AND METHODS: Motion-corrected DTI analysis was performed on data sets obtained at 1.5T from 32 fetuses scanned between 21.29 and 37.57 (median 31.86) weeks. Results were compared to 32 preterm infants scanned at 3T between 27.43 and 37.14 (median 33.07) weeks. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were quantified by region of interest measurements and tractography was performed. RESULTS: Fetal DTI was successful in 84% of fetuses for whom there was sufficient data for DTI estimation, and at least one tract could be obtained in 25 cases. Fetal FA values increased and ADC values decreased with age at scan (PLIC FA: p = 0.001; R2 = 0.469; slope = 0.011; splenium FA: p < 0.001; R2 = 0.597; slope = 0.019; thalamus ADC: p = 0.001; R2 = 0.420; slope = - 0.023); similar trends were found in preterm infants. CONCLUSION: This study demonstrates that stable DTI is feasible on fetuses and provides evidence for normative values of diffusion properties that are consistent with aged matched preterm infants.

Effect of PVA coating on the electric field intensity distribution and laser damage performance of fused silica optics surfaces.

A facile method was proposed to enhance the laser damage performance of the fused silica optics by coating a PVA film on the rear surface of the optics. FDTD simulation result suggests that the PVA coating with suitable thickness can transfer the maximal electric field intensity from the rear surface to the interface between the coating and air, and reduce the electric field intensity of the rear surface remarkably. LIDT tests reveal that the LIDT of fused silica with PVA coating changed periodically with respect to the coating thickness, which agrees well with the tendency predicted by FDTD simulation. Finally, PVA coatings with a thickness of 60 nm and 300 nm can both improve the LIDT of AMP-treated fused silica by ~20%, which provide a potential to be applied in high power laser facility.

Age-related changes in the effects of strength training on lower leg muscles in healthy individuals measured using MRI.

BACKGROUND: We previously measured the rate of regaining muscle strength during rehabilitation of lower leg muscles in patients following lower leg casting. Our primary aim in this study was to measure the rate of gain of strength in healthy individuals undergoing a similar training regime. Our secondary aim was to test the ability of MRI to provide a biomarker for muscle function. METHODS: Men and women were recruited in three age groups: 20-30, 50-65 and over 70 years. Their response to resistance training of the right lower leg twice a week for 8 weeks was monitored using a dynamometer and MRI of tibialis anterior, soleus and gastrocnemius muscles at 2 weekly intervals to measure muscle size (anatomical cross-sectional area (ACSA)) and quality (T2 relaxation). Forty-four volunteers completed the study. RESULTS: Baseline strength declined with age. Training had no effect in middle-aged females or in elderly men in dorsiflexion. Other groups significantly increased both plantarflexion and dorsiflexion strength at rates up to 5.5 N m week-1 in young females in plantarflexion and 1.25 N m week-1 in young males in dorsiflexion. No changes were observed in ACSA or T2 in any age group in any muscle. CONCLUSION: Exercise training improves muscle strength in males at all ages except the elderly in dorsiflexion. Responses in females were less clear with variation across age and muscle groups. These results were not reflected in simple MRI measures that do not, therefore, provide a good biomarker for muscle atrophy or the efficacy of rehabilitation.

Low-loss polarization-maintaining THz photonic crystal fiber with a triple-hole core.

In this paper, we report a novel low-loss and polarization-maintaining terahertz (THz) photonic crystal fiber with a triple-hole unit inside the core. The properties of birefringence, effective material loss, confinement loss, bending loss, power fraction, dispersion, and single-mode condition are analyzed in detail by using the finite element methods. Simulation results show that high birefringence at a level of 10-2 can be achieved by simply reducing the diameter of one air hole of the triple-hole core. And low effective material loss down to 30% of its bulk material loss can be achieved in our interested band around 3 THz, due to the high core porosity of the designed triple-hole core. Moreover, this design dramatically facilitates the fabrication process, because of the typical hexagonal structure with all circular air holes and avoiding the troublesome multiple sub-wavelength air holes in the core area. The results reveal that this proposal has potential for efficient THz transmission and other functional applications.

Comparison of corneal biomechanics after microincision lenticule extraction and small incision lenticule extraction.

OBJECTIVES: To evaluate and compare the change in corneal biomechanical properties after microincision lenticule extraction (MILE) and small incision lenticule extraction (SMILE). METHODS: In this prospective study, 60 eyes received MILE surgery with 2 mm opening incision, while 64 eyes received SMILE procedure with 5 mm opening incision. Corneal hysteresis (CH), corneal resistance factor (CRF) and 37 other biomechanical waveform parameters were quantitatively assessed using ocular response analyser (ORA) preoperatively and up to 6 months postoperatively. All changes were calculated as the difference between preoperative and postoperative values (Δ). RESULTS: Both CH and CRF values decreased significantly after MILE and SMILE (p<0.001). ΔCRF (o=0.028) and ΔCRF index (ΔCRF/preoperative CRF) (p=0.043) were statistically lower for all eyes at 1-week follow-up. ΔCH index (ΔCH/preoperative CH) was statistically lower at 1-week (p=0.043) and 1-month (p=0.015) follow-ups in MILE group when compared with SMILE group. In both MILE and SMILE group, ΔCH index and ΔCRF index were positively correlated with preoperative manifest refraction spherical equivalent, residual stromal thickness (RST) index (RST/preoperative central corneal thickness) and negatively correlated with lenticule thickness (p<0.05). CONCLUSIONS: Both MILE and SMILE procedures significantly altered the biomechanical characteristics of cornea. Smaller opening incision was associated with less reduction in ORA parameters during early postoperative period.