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Choroidal structure in subtypes of polypoidal choroidal vasculopathy determined by binarization of optical coherence tomographic images
摘要： Importance: Chorodial structure in subtypes of polypoidal choroidal vasculopathy. Background: To evaluate choroidal vascularity in the eyes of patients with polypoidal choroidal vasculopathy (PCV) with and without choroidal vascular hyperpermeability (CVH). Design: A hospital-based retrospective study. Participants: Fifty-eight PCV patients (28 with CVH; 30 without CVH) and 30 normal controls were included in this study. Methods: All study subjects underwent spectral-domain optical coherence tomography with enhanced depth imaging, and the choroidal images were binarized into the luminal area and stromal area. Main outcome measures: Choroidal vascularity index (CVI) and subfoveal choroidal thickness (SFCT). Results: Compared to normal controls, patients with PCV showed no obvious difference in SFCT (p = 0.510), but significantly lower CVI (p = 0.003). Among PCV patients, the CVI in eyes with CVH was significantly greater than that in those without CVH (65.78 ± 4.70 vs. 62.28 ± 3.90; p = 0.002), and a significant difference in SFCT was also found between the two subtypes of PCV (340.8 ± 89.2 vs. 250.4 ± 67.7; p < 0.001). Conclusions and Relevance: PCV eyes with CVH have a greater CVI and a thicker SFCT than those without CVH. The significant differences in choroidal vascularity between the two subtypes of PCV may broaden our understanding of the pathogenesis of this disease and contribute to significant improvements in treatment.
关键词： polypoidal choroidal vasculopathy,choroidal thickness,optical coherence tomography,choroidal vascular hyperpermeability,Choroidal vascularity index
更新于2025-09-19 17:15:36
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Thermopower Modulation Clarification of the Operating Mechanism in Wide Bandgap BaSnO <sub/>3</sub> -SrSnO <sub/>3</sub> Solid-Solution Based Thin Film Transistors
摘要： The transparent oxide semiconductor (TOS) with large bandgap (Eg ≈ 4 eV) based thin-film transistors (TFTs) showing both high carrier mobility and UV–visible transparency has attracted increasing attention as a promising component for next generation optoelectronics. Among TOSs, BaSnO3–SrSnO3 solid-solutions (Eg = 3.5–4.2 eV) are good candidates because the single crystal shows very high mobility. However, the TFT performance has not been optimized due to the lack of fundamental knowledge especially the effective thickness (teff ) and the carrier effective mass (m*). Here, it is demonstrated that the electric field thermopower (S) modulation method addresses this problem by combining with the standard volume carrier concentration (n3D) dependence of S measurements. By comparing the electric field accumulated sheet carrier concentration (n2D) and n3D at same S, it is clarified that the teff (≈n2D/n3D) of the conducting channel becomes thicker with increasing Sr concentration, whereas the m* becomes lighter. The former would be due to the increase of Eg and latter would be due to the enhancement of overlap population of neighboring Sn 5s orbitals. The present analyses technique is useful to experimentally clarify the teff and m*, and essentially important to realize advanced TOS-based TFTs showing both high optical transparency and high mobility.
关键词： electric field thermopower modulation,effective thickness,thin film transistors,BaSnO3–SrSnO3 solid solution,effective mass
更新于2025-09-19 17:15:36
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Comparison of optical quality and distinct macular thickness in femtosecond laser-assisted versus phacoemulsification cataract surgery
摘要： Background: Optical quality and macular thickness changing optical quality is rarely reported after femtosecond laser-assisted cataract surgery (FLACS). In current research, we evaluated optical quality recovery and distinct macular thickness changes after FLACS and phacoemulsification cataract surgery (PCS). Methods: A total of 100 cataract patients (100 eyes) were included (50 eyes for the FLACS group and 50 eyes for the PCS group). Modulation transfer function (MTF), point spread function (PSF) and dysfunctional lens index (DLI) were measured by a ray-tracing aberrometer (iTrace). Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were also assessed pre-operation,1 week and 1 month after surgery. The MTF values at spatial frequencies of 5, 10, 15, 20, 25 and 30 cycles/degree (c/d) were selected. We used optical coherence tomography (OCT) to assess the macular thickness of different regions pre-operatively and1month after the surgery. Results: In PCS group, we found the statistically significant differences between pre-operation and post-operation in DLI (p < 0.0001), PSF (strehl ratio, SR) (p = 0.027) and MTF (p = 0.028), but not intraocular pressure (IOP) (p = 0.857). The differences between pre-operation and post-operation for DLI (p = 0.031), SR (p = 0.01) and IOP (p = 0.03), but not MTF (p = 0.128) were also found in FLACS group. The differences were statistically significant when the spatial frequencies were at 5, 10 and 25 (p = 0.013, 0.031 and 0.048) between pre-operation and post-operation in PCS group but not FLACS group at 1 month. In PCS group, we found the differences between pre-operation and post-operation in nasal inter macular ring thickness (NIMRT) (p = 0.03), foveal volume (FV) (p = 0.034) and average retinal thickness (ART) (p = 0.025) but not FLACS group at 1 month. Conclusion: FLACS is safe that did not cause significant increase of macular thickness in current study. However, it also cannot produce better optical quality. In contrast, PCS can produce macular thickness changes, but better optical quality recovery. The slightly retinal change may not affect optical quality.
关键词： Macular thickness,Femtosecond laser-assisted cataract surgery (FLACS),Point spread function (PSF),Modulation transfer function (MTF),Phacoemulsification cataract surgery (PCS),Dysfunctional lens index (DLI),Optical quality
更新于2025-09-19 17:13:59
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Effectiveness of intraoperative intraocular lens use on improving surgical safety for dense cataract phacoemulsification: a randomized controlled trial
摘要： We designed this study to assess if surgical safety can be improved by intraoperative use of intraocular lens (IOL) for cataract phacoemulsification. We performed phacoemulsification cataract removal on 401 patients. We randomly assigned these patients into three groups: the standard setting (Group I, n = 134), with reduced vacuum and flow rate (Group II, n = 137), and with IOL insertion before the last quadrant was emulsified with standard setting (Group III, n = 130). The primary outcomes included the risk of posterior capsular rupture (PCR), ultrasound time, energy, and complications. The secondary outcomes included central corneal thickness (CCT), CCT changes, endothelial cells (ETC) counting, ETC loss, and the best corrected distance visual acuity (BCVA) measured on day 1, day 7 and day 30. If PCR occurred, we emulsified the residual lens materials after insertion of IOL and clean of the prolapsed vitreous. We found that the risk of PCR in Group III (0/130) was lower than Group I (9/134, corrected relative risk (RR) = 18.44, 95% CI: 1.08–313.56) and Group II (3/137, corrected RR = 6.64, 95% CI: 0.35–27.41). Group III showed better BCVA on day 1 and 7, less ECC loss on day 7 and 30, and less CCT increase on day 1 and 7. No cases converted to extracapsular cataract extraction. No residual lens materials misdirected into vitreous cavity. Intraoperative use of IOL can improve surgical safety for dense cataract phacoemulsification.
关键词： cataract phacoemulsification,intraocular lens,surgical safety,posterior capsular rupture,ultrasound time,endothelial cells loss,central corneal thickness
更新于2025-09-19 17:13:59
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Optimization of the In0.3Ga0.7As-Layer Thickness in a Triple-Junction In0.3Ga0.7As/GaAs/In0.5Ga0.5P Solar Cell
摘要： The optimum absorbing-layer thickness in the bottom In0.3Ga0.7As subcell of a triple-junction In0.3Ga0.7As/GaAs/In0.5Ga0.5P solar cell is sought for using the Sentaurus TCAD software package as a factor of the minority charge-carrier lifetime in this layer. The lifetime is set in the range from 17 ps to 53 ns. The calculation results show that the optimum thickness varies from 0.9 to 7.5 μ m. In addition, the contribution of the bottom In0.3Ga0.7As subcell to the efficiency of this triple-junction solar cell is estimated at various lifetime values. Its value varies from 1 to 7%.
关键词： numerical modeling,Sentaurus TCAD,In0.3Ga0.7As,solar cell,optimum thickness
更新于2025-09-19 17:13:59
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Terahertz intersubband transitions in GaAsBi/AlGaAs single quantum well heterostructure
摘要： GaAsBi/AlGaAs single quantum well conduction band structure, energy levels, and their corresponding wavefunctions have been calculated by solving the Schr?dinger equation. The influences of the heterostructure parameters on the intersubband transition (ISBT) frequency within the terahertz (THz) domain have been investigated. The results show that the quantum well width has a great impact on the THz ISBT frequency. In particular, an ISBT with a frequency of 2.611 THz (10.80?meV) has been obtained for specifically optimized parameters. The study of the intersubband optical absorption coefficient (OAC) was centered in the frequency band of 2 – 14 THz ( ~ 8 – 58 meV), therefore the corresponding results are useful for the optimization of THz detectors. Correspondingly, by changing the thickness of the active layer the number of the OAC peaks has been tuned. The dipole matrix element and the Fermi occupation function have been also studied in detail. Furthermore, the influences coming from the incidence angle on the OAC intensity were numerically investigated. The obtained results could be beneficial for the design and the optimization of devices operating in the THz frequency band.
关键词： GaAsBi quantum well,Terahertz region,Intersubband transitions,Optical absorption coefficient,Incidence angle,Active layer thickness
更新于2025-09-19 17:13:59
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A Randomized, Controlled Trial on the Effectiveness of Photobiomodulation Therapy and Nona??Contact Selectivea??Field Radiofrequency on Abdominal Adiposity in Adolescents With Obesity
摘要： Background and Objectives: Structured physical activities and dietary control have traditionally been used with the aim of controlling obesity. However, effective auxiliary modalities still needed to reduce local obesity, specifically abdominal obesity. This study examined the adjunct effect of photobiomodulation therapy (PBMT), and non‐contact selective‐field radiofrequency (NcRF) on abdominal adiposity in adolescents with obesity. Study Design/Materials and Methods: Fifty‐four adolescents with obesity (33 females and 21 males) took part in this study and were distributed randomly into three treatment‐based groups. Control group (n = 18, age; 14.61 ± 1.14 years), PBMT group (n = 18, age; 14.22 ± 0.88 years), and NcRF group (n = 18, age; 15.11 ± 0.96 years). A dietary control plan of 1,000–1,200 kcal/day, and a 60‐minute aerobic exercise program conducted day‐by‐day over 4 weeks were provided for all participants. Additionally, the PBMT group received 12 20‐minute PBMT on the abdominal area (energy/session ~4.08 J/cm2) thrice/week, and the NcRF group underwent four 30‐minute treatments with NcRF on the abdominal area once/week. Waist/hip ratio (W‐to‐H ratio), intra‐abdominal fat thickness (IAFT), and the subcutaneous‐abdominal fat thickness (SAFT) were observed at the baseline and after 4 weeks. Results: The W‐to‐H ratio and SAFT reduced significantly in the PBMT group compared with either the control group (P = 0.001 and 0.001, respectively) or the NcRF group (P < 0.001 and P = 0.046, respectively) post‐intervention. However, the IAFT and IAFT/SAFT ratio did not differ significantly among the study groups (P > 0.05). Conclusion: Our analysis shows that PBMT is more efficient than NcRF for the reduction of W‐to‐H ratio and SAFT in adolescents with obesity.
关键词： laser lipolysis,635 nm‐laser diode,abdominal adipocytes,contactless radiofrequency,fat thickness
更新于2025-09-19 17:13:59
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Terahertz radiation enhanced by target ablation during the interaction of high intensity laser pulse and micron-thickness metal foil
摘要： When an ultra-intense relativistic laser is irradiated on a solid target, terahertz (THz) pulses can be generated by coherent transition radiation when the laser-driven electron beams cross the rear surface of the target. The radiation energy depends on the number and energy of the electrons. By introducing a milli-joule picosecond ablation laser pulse, an underdense preplasma with a scale length of micrometers is generated at the front surface of the target. Electron beams with more charge and higher energy can be produced during the interaction between the following main laser pulse and the preplasma, which enhance the THz radiation and affect the radiation angle. Two dimensional particle-in-cell simulations demonstrate the improvement of electron beams and a nearly tenfold enhancement of THz radiation energy is observed.
关键词： high intensity laser pulse,particle-in-cell simulations,coherent transition radiation,terahertz radiation,target ablation,micron-thickness metal foil
更新于2025-09-19 17:13:59
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Sub-400 nm film thickness determination from transmission spectra in organic distributed feedback lasers fabrication
摘要： The design and fabrication of thin-film based organic optoelectronic devices require knowledge of the film optical properties. A low-cost and non-destructive method often used for optical characterization of films is the well-established spectrophotometric envelope method. However, this method is typically limited to thickness above 400 nm, a value often higher than that of the films involved in these devices. This paper studies a procedure to obtain the thickness of sub-400 nm active films from their spectrophotometric trace when the refractive index is previously known. The proposed procedure is based on comparing the experimental transmission spectrum in the transparent spectral window with that obtained by simulation. The capabilities of the proposed method are demonstrated here by its application in the fabrication of organic distributed-feedback lasers where a fine control of film thickness is important to obtain an optimized and reproducible response. Results were verified with other techniques, such as ellipsometry and profilometry. Thus, with the proposed method, film thickness can be easily determined down to 40 nm maintaining an accuracy of about 5 nm even for films with low refractive index (1.5-1.7). Different methods to determine refractive index of these films are also discussed.
关键词： Optical characterization,Thin film thickness,Transmission spectra,Distributed feedback lasers
更新于2025-09-19 17:13:59
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Influence of Electron Transport Layer (TiO2) Thickness and Its Doping Density on the Performance of CH3NH3PbI3-Based Planar Perovskite Solar Cells
摘要： Simulation studies are vital to understanding solar cell performance and in optimal device design for high-efficiency solar cells. Cell performance is sensitive to many factors, including device architecture, energy band alignment at the interfaces, materials used for photogeneration, charge extraction, doping density and thickness of various layers. The role of electron transport layer (ETL) thickness and its doping density on device performance is explored in this work. As the ETL thickness is increased from 10 nm to 200 nm, both fill factor (FF) and efficiency remain high up to 40 nm, at 0.85 and 28.04%, respectively, and beyond 40 nm, they decrease gradually due to a sharp increase in series resistance, reaching zero at 200 nm. However, Jsc and Voc remained unchanged up to an ETL thickness of about 150 nm and 160 nm, respectively. These results were confirmed by contour plots of the simulated Voc, Jsc, FF and efficiency results. We observed that when ETL approached 200 nm, Jsc and Voc decreased to zero and 0.88 V, respectively. This can be attributed to very high series resistance and recombination in the cell. Donor concentration variation in the ETL from 1017/cm3 to 1020/cm3 has much less impact on Jsc, and Voc remains unchanged. However, fill factor and efficiency improved, which might be due to an increase in conductivity in the ETL. Our result shows that for an optimized device, with an AM 1.5 spectrum, a cell efficiency of 29.64% was achieved with Voc, Jsc and fill factor of 1.241 V, 28.70 mA/cm2 and 0.83, respectively.
关键词： contour map,ETL doping density,light I–V,ETL thickness,CH3NH3PbI3
更新于2025-09-19 17:13:59