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To realize compact and denser photonic integrated circuits, three-dimensional integration has been widely accepted and researched. In this article, we demonstrate the operation of a 3D integrated silicon photonic platform fabricated through wafer bonding. Benefiting from the wafer bonding process, the material of all layers is c-Si, which ensures that the mobility is high enough to achieve a nanosecond response via the p-i-n diode shifter. Optical components, including multimode interferences (MMIs), waveguide crossing, and Mach-Zehnder interferometer (MZI)-based switch, are fabricated in different layers and exhibit great performance. The interlayer coupler and crossing achieve a 0.98â dB coupling loss and <-43.58â dB cross talk, while the crossing fabricated in the same layer shows <-36.00â dB cross talk. A nanosecond-order switch response is measured in different layers.
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OBJECTIVE: To develop preoperative nomograms using risk factors based on clinicopathological and MRI for predicting the risk of positive surgical margin (PSM) after radical prostatectomy (RP). PATIENTS AND METHODS: This study retrospectively enrolled patients who underwent prostate MRI before RP at our center between January 2015 and November 2022. Preoperative clinicopathological factors and MRI-based features were recorded for analysis. The presence of PSM (overall PSM [oPSM]) at pathology and the multifocality of PSM (mPSM) were evaluated. LASSO regression was employed for variable selection. For the final model construction, logistic regression was applied combined with the bootstrap method for internal verification. The risk probability of individual patients was visualized using a nomogram. RESULTS: In all, 259 patients were included in this study, and 76 (29.3%) patients had PSM, including 40 patients with mPSM. Final multivariate logistic regression revealed that the independent risk factors for oPSM were tumor diameter, frank extraprostatic extension, and annual surgery volume (all p < 0.05), and the nomogram for oPSM reached an area under the curve (AUC) of 0.717 in development and 0.716 in internal verification. The independent risk factors for mPSM included the percentage of positive cores, tumor diameter, apex depth, and annual surgery volume (all p < 0.05), and the AUC of the nomogram for mPSM was 0.790 in both development and internal verification. The calibration curve analysis showed that these nomograms were well-calibrated for both oPSM and mPSM. CONCLUSIONS: The proposed nomograms showed good performance and were feasible in predicting oPSM and mPSM, which might facilitate more individualized management of prostate cancer patients who are candidates for surgery.
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Magnetic Resonance Imaging , Margins of Excision , Nomograms , Prostatectomy , Prostatic Neoplasms , Humans , Male , Prostatectomy/methods , Prostatic Neoplasms/surgery , Prostatic Neoplasms/pathology , Prostatic Neoplasms/diagnostic imaging , Retrospective Studies , Middle Aged , Aged , Magnetic Resonance Imaging/methods , Risk FactorsABSTRACT
Actinides (An)-bearing colloids could facilitate An migration in the environment. However, little is known about the transport behavior of An(III)-silicate colloids, which are readily formed by the reaction of An3+ with silicic acid under environmental conditions. Column experiments were conducted to investigate the transport of Eu(III)-silicate colloids (chemical analog of An(III)-silicate colloids) in water-saturated porous media as a function of pH, ionic strength (IS) and the presence of fulvic acid (FA). The results showed that colloid transport was more favorable at relatively low IS (≤ 50 mM) and high pH levels (pH ≥ 7). The presence of FA (5-10 mg/L) significantly enhanced the colloid transport. Under high IS (≥ 100 mM), the transport feature of colloids was turned from blocking to ripening due to the on-going aggregation of colloids. Additionally, an interesting elemental fractionation, i.e., a discrepancy in the breakthrough curves (BTCs) with respect to the C/C0 values of Si and Eu, was observed in the IS of 100-500 mM. A detailed investigation indicated that the elemental fractionation could be attributed to the partial Si dissolution of the colloids, the heterogeneity of the colloid size and element composition, and particle size fractionation during colloid transport. Extended Derjaguin-Landau-Verwey-Overbeek interaction energy calculations and convective-dispersive equation modeling were performed to illustrate variations in the colloid transport profiles. These findings illustrate the importance of Si dissolution in the migration of metal-silicate colloids and highlight the significant influence of the heterogeneity of colloid size and composition on the transport/migration behavior of colloids in the environment.
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The mode rotator is an important component in a PLC-based mode-division multiplexing (MDM) system, which is used to implement high-order modes with vertical intensity peaks, such as LP11b mode conversions from LP11a in PLC chips. In this paper, an LP11 mode rotator based on a polymer/silica hybrid inverted ridge waveguide is demonstrated. The proposed mode rotator is composed of an asymmetrical waveguide with a trench. According to the simulation results, the broadband conversion efficiency between the LP11a and LP11b modes is greater than 98.5%, covering the C-band after optimization. The highest mode conversion efficiency (MCE) is 99.2% at 1550 nm. The large fabrication tolerance of the proposed rotator enables its wide application in on-chip MDM systems.
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OBJECTIVE: To investigate the diagnostic performance of MRI in detecting clinically significant prostate cancer (csPCa) and prostate cancer (PCa) in patients with prostate-specific antigen (PSA) levels of 4-10 ng/mL. METHODS: A computerized search of PubMed, Embase, Cochrane Library, Medline, and Web of Science was conducted from inception until October 31, 2023. We included articles on the use of MRI to detect csPCa or PCa at 4-10 ng/mL PSA. The primary and secondary outcomes were MRI performance in csPCa and PCa detection, respectively; the estimates of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were pooled in a bivariate random-effects model. RESULTS: Among the 19 studies (3879 patients), there were 10 (2205 patients) and 13 studies (2965 patients) that reported MRI for detecting csPCa or PCa, respectively. The pooled sensitivity and specificity for csPCa detection were 0.84 (95% confidence interval [CI], 0.79-0.88) and 0.76 (95%CI, 0.65-0.84), respectively, for PCa detection were 0.82 (95%CI, 0.75-0.87) and 0.74 (95%CI, 0.65-0.82), respectively. The pooled NPV for csPCa detection was 0.91 (0.87-0.93). Biparametric magnetic resonance imaging also showed a significantly higher sensitivity and specificity relative to multiparametric magnetic resonance imaging (both p < 0.01). CONCLUSION: Prostate MRI enables the detection of csPCa and PCa with satisfactory performance in the PSA gray zone. The excellent NPV for csPCa detection indicates the possibility of biopsy decision-making in patients in the PSA gray zone, but substantial heterogeneity among the included studies should be taken into account. CLINICAL RELEVANCE STATEMENT: Prostate MRI can be considered a reliable and satisfactory tool for detecting csPCa and PCa in patients with PSA in the "gray zone", allowing for reducing unnecessary biopsy and optimizing the overall examination process. KEY POINTS: Prostate-specific antigen (PSA) is a common screening tool for prostate cancer but risks overdiagnosis. MRI demonstrated excellent negative predictive value for prostate cancer in the PSA gray zone. MRI can influence decision-making for these patients, and biparametric MRI should be further evaluated.
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Pr3+-doped fluorotellurite glass fibers (PDFTFs) were fabricated by using a rod-in-tube method. By using a 976/1400â nm dual-wavelength upconversion pump technique, an intense emission at 605â nm was obtained from a 6â cm long PDFTF, which was attributed to the transition 1D2 â 3H4 of Pr3+ ions. With an increase in power of the 1400â nm laser from â¼34 to â¼136â mW, the spectral bandwidth of the 605â nm emission decreased and the intensity of the 605â nm emission increased monotonically, indicating the generation of 605â nm amplified spontaneous emission (ASE). To the best of our knowledge, this is the first report of 605â nm ASE in PDFTFs. Our results showed that PDFTFs had the potential for constructing red fiber lasers and amplifiers.
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How plants find a way to thrive in alpine habitats remains largely unknown. Here we present a chromosome-level genome assembly for an alpine medicinal herb, Triplostegia glandulifera (Caprifoliaceae), and 13 transcriptomes from other species of Dipsacales. We detected a whole-genome duplication event in T. glandulifera that occurred prior to the diversification of Dipsacales. Preferential gene retention after whole-genome duplication was found to contribute to increasing cold-related genes in T. glandulifera. A series of genes putatively associated with alpine adaptation (e.g. CBFs, ERF-VIIs, and RAD51C) exhibited higher expression levels in T. glandulifera than in its low-elevation relative, Lonicera japonica. Comparative genomic analysis among five pairs of high- vs low-elevation species, including a comparison of T. glandulifera and L. japonica, indicated that the gene families related to disease resistance experienced a significantly convergent contraction in alpine plants compared with their lowland relatives. The reduction in gene repertory size was largely concentrated in clades of genes for pathogen recognition (e.g. CNLs, prRLPs, and XII RLKs), while the clades for signal transduction and development remained nearly unchanged. This finding reflects an energy-saving strategy for survival in hostile alpine areas, where there is a tradeoff with less challenge from pathogens and limited resources for growth. We also identified candidate genes for alpine adaptation (e.g. RAD1, DMC1, and MSH3) that were under convergent positive selection or that exhibited a convergent acceleration in evolutionary rate in the investigated alpine plants. Overall, our study provides novel insights into the high-elevation adaptation strategies of this and other alpine plants.
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We propose a strip loaded amplifier employing SU-8 as the loaded waveguide and nanoparticles (NPs)-polymethyl methacrylate (PMMA) as the cladding layer. By leveraging the undoped SU-8 loaded waveguide, the polymer waveguide amplifier accomplished remarkably low transmission losses, reaching as low as 1.8â dB/cm at 1530â nm. We prepared NPs-PMMA nanocomposite by utilizing NaLu0.1Y0.7F4: Er3+, Yb3+ @NaLuF4 core-shell nanoparticles, which exhibited a significantly enhanced lifetime of 6.15â ms. An internal net gain of up to 17.7â dB was achieved on a strip loaded waveguide with a length as short as 0.5â cm when the on-chip pump power was 77â mW. Signal enhancement (SE) was measured at different wavelengths, revealing that the strip loaded waveguide exhibited broadband SE ranging from 1510â nm to 1570â nm, covering the C-band. To the best of our knowledge, this work has achieved the highest gain results reported thus far on a polymer matrix and provides an efficient method for optical amplification in passive devices on silicon and Si3N4 platforms, leveraging the ease of integration of polymer materials with diverse photonic platforms.
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BACKGROUND: There are inconsistent results on the Edinburgh Postnatal Depression Scale's (EPDS) factor structure and longitudinal invariance among different cultures. Furthermore, limited relevant studies in Chinese pregnant women exist. PURPOSE: To test the factor structure of the Chinese Mainland EPDS during pregnancy and conduct longitudinal invariance analyses. METHODS: A national multi-centre cohort study was conducted among 1207 pregnant women selected consecutively by convenience sampling from five hospitals in Zhuhai, Taiyuan, Haidian, Changchun, and Shenzhen in China between August 2015 and October 2016. Depression was measured by the EPDS during gestational weeks 10-13, 15-18, 23-25, 30-32 and 36-37, respectively.s RESULTS: Three factors with eigenvalues nearly larger than 1.0 were optimal for the Chinese Mainland EPDS, labelled "anxiety," "anhedonia," and "depression," and contained items 3-5, 1-2, and 6-10, respectively. The confirmatory factor analysis results of standardized root mean square residual (SRMR) = 0.034, root mean square error of approximation (RMSEA) = 0.049, comparative fit index (CFI) = 0.968, Tucker-Lewis index (TLI) = 0.954, and χ2, p < 0.05 indicated good fit. For the longitudinal invariance tests, the configural invariance was met, with the CFI and TLI both higher than 0.90 and the RMSEA lower than 0.08 (CFI = 0.919, TLI = 0.908, and RMSEA = 0.034). The metric-, scalar-, and strict invariances were met. CONCLUSIONS: The three-factor model of the Chinese Mainland EPDS is invariant in pregnancy, suggesting stability and comparability in identifying the women screened positive at different points during pregnancy and making the scale feasible to screen prenatal depression and anxiety simultaneously.
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Pregnant Women , Psychiatric Status Rating Scales , Psychometrics , Humans , Female , Pregnancy , China , Adult , Psychometrics/methods , Psychometrics/instrumentation , Psychiatric Status Rating Scales/standards , Pregnant Women/psychology , Factor Analysis, Statistical , Cohort Studies , Surveys and Questionnaires , Reproducibility of Results , Longitudinal Studies , Depression, Postpartum/diagnosis , Depression, Postpartum/psychology , Depression/diagnosis , Depression/psychology , East Asian PeopleABSTRACT
OBJECTIVES: To explore the association between lower extremity muscle features from CTA and peripheral arterial disease (PAD) severity using digital subtraction angiography (DSA) as reference standard. METHODS: Informed consent was waived for this Institutional Review Board approved retrospective study. PAD patients were recruited from July 2016 to September 2020. Two radiologists evaluated PAD severity on DSA and CTA using runoff score. The patients were divided into two groups: mild PAD (DSA score ≤ 7) vs. severe PAD (DSA score > 7). After segmenting lower extremity muscles from CTA, 95 features were extracted for univariable analysis, logistic regression model (LRM) analysis, and sub-dataset analysis (PAD prediction based on only part of the images). AUC of CTA score and LRMs for PAD prediction were calculated. Features were analyzed using Student's t test and chi-squared test. p < 0.05 was considered statistically significant. RESULTS: A total of 56 patients (69 ± 11 years; 38 men) with 56 lower legs were enrolled in this study. The lower leg muscles of mild PAD group (36 patients) showed higher CT values (44.6 vs. 39.5, p < 0.001) with smaller dispersion (35.6 vs. 41.0, p < 0.001) than the severe group (20 patients). The AUC of CTA score, LRM-I (constructed with muscle features), and LRM-II (constructed with muscle features and CTA score) for PAD severity prediction were 0.81, 0.84, and 0.89, respectively. The highest predictive performance was observed in the image subset of the middle and inferior segments of lower extremity (LRM-I, 0.83; LRM-II, 0.90). CONCLUSIONS: Lower extremity muscle features are associated with PAD severity and can be used for PAD prediction. CRITICAL RELEVANCE STATEMENT: Quantitative image features of lower extremity muscles are associated with the degree of lower leg arterial stenosis/occlusion and can be a beneficial supplement to the current imaging methods of vascular stenosis evaluation for the prediction of peripheral arterial disease severity. KEY POINTS: ⢠Compared with severe PAD, lower leg muscles of mild PAD showed higher CT values (39.5 vs. 44.6, p < 0.001). ⢠Models developed with muscle CT features had AUC = 0.89 for predicting PAD. ⢠PAD severity prediction can be realized through the middle and inferior segment of images (AUC = 0.90).
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The associations between multiple sleep characteristics and smoking behavior are inconsistent, and it is unclear which sleep characteristics are most crucial for tobacco prevention. This study aimed to explore the associations between smoking status/intensity and multiple sleep characteristics and to identify the potential core domain of smoking-related sleep using network analysis. Data were obtained from a survey of cancer-related risk factors among Chinese adults. Logistic regression models were used to quantify the associations between sleep characteristics and smoking status/intensity. Network analyses were employed to identify the core sleep characteristics. A total of 5,228 participants with a median age of 44 years old were included in the study. Current smoking was significantly positively associated with long nap time, difficulty falling asleep, late bedtime, getting up after 7 am, and waking up earlier than expected. There was significant positive association between current smoking and short sleep duration in young adults under 45 years old. Late bedtime and getting up after 7 am were only associated with current heavy smoking, but not current light smoking. Network analyses showed that multiple smoking-related sleep characteristics were interconnected, with difficulty falling asleep and late bedtime as central characteristics in the network. The study found that the associations between sleep characteristics and smoking varied by age and smoking intensity and highlights the potential benefits of sleep health promotion in smoking cessation, with a particular focus on difficulty falling asleep and late bedtime.
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Sleep Initiation and Maintenance Disorders , Sleep , Young Adult , Humans , Adult , Middle Aged , Smoking/adverse effects , Smoking/epidemiology , Surveys and Questionnaires , China/epidemiologyABSTRACT
In this work, programmable optical switching integrated chips for 4-bit binary true/inverse/complement optical code conversions (OCCs) are proposed based on fluorinated photopolymers. Fluorinated bis-phenol-A novolac resin (FAR) with low absorption loss and fluorinated polyacrylate (FPA) with high thermal stability are self-synthesized as core and cladding layer, respectively. The basic architecture of operating unit for the photonic chip designed is composed of directional coupler Mach-Zehnder interferometer (DC-MZI) thermo-optic (TO) switching, X-junction, and Y-bunching waveguide structures. The waveguide module by cascading 16 operating units could realize OCCs function through optical transmission matrix. The response time of the 4-bit binary OCCs is measured as about 300 µs. The insertion loss and extinction ratio of the actual chip are obtained as about 10.5â dB and 15.2â dB, respectively. The electric driving power consumption for OCCs is less than 6â mW. The true/inverse/complement OCCs are achieved by the programmable modulation circuit. The proposed technique is suitable for achieving optical digital computing system with high-speed signal processing and low power consumption.
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OBJECTIVE: To assess the effect of preoperative MRI with standardized Prostate Imaging-Reporting and Data System (PI-RADS) assessment on pathological outcomes in prostate cancer (PCa) patients who underwent radical prostatectomy (RP). PATIENTS AND METHODS: This retrospective cohort study included patients who had undergone prostate MRI and subsequent RP for PCa between January 2017 and December 2022. The patients were divided into the PI-RADS group and the non-PI-RADS group according to evaluation scheme of presurgery MRI. The preoperative characteristics and postoperative outcomes were retrieved and analyzed. The pathological outcomes included pathological T stage (pT2 vs. pT3-4) and positive surgical margins (PSMs). Patients were further stratified according to statistically significant preoperative variables to assess the difference in pathological outcomes. A propensity score matching based on the above preoperative characteristics was additionally performed. RESULTS: A total of 380 patients were included in this study, with 201 patients in the PI-RADS group and 179 in the non-PI-RADS group. The two groups had similar preoperative characteristics, except for clinical T stage (cT). As for pathological outcomes, the PI-RADS group showed a significantly lower percentage of pT3-4 (21.4% vs. 48.0%, p < 0.001), a lower percentage of PSMs (31.3% vs. 40.9%, p = 0.055), and a higher concordance between the cT and pT (79.1% vs. 64.8%, p = 0.003). The PI-RADS group also showed a lower proportion of pT3-4 (p < 0.001) in the cT1-2 subgroup and the cohort after propensity score matching. The PSM rate of cT3 patients was reduced by 39.2% in the PI-RADS group but without statistical significance (p = 0.089). CONCLUSIONS: Preoperative MRI with standardized PI-RADS assessment could benefit the decision-making of patients by reducing the rate of pathologically confirmed non-organ-confined PCa after RP and slightly reducing the PSM rate compared with non-PI-RADS assessment.
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Prostate , Prostatic Neoplasms , Male , Humans , Prostate/diagnostic imaging , Prostate/surgery , Prostate/pathology , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/surgery , Prostatic Neoplasms/pathology , Magnetic Resonance Imaging/methods , Retrospective Studies , Prostatectomy/methods , Neoplasm Grading , Margins of ExcisionABSTRACT
OBJECTIVE: To construct a simplified grading system based on MRI features to predict positive surgical margin (PSM) after radical prostatectomy (RP). METHODS: Patients who had undergone prostate MRI followed by RP between January 2017 and January 2021 were retrospectively enrolled as the derivation group, and those between February 2021 and November 2022 were enrolled as the validation group. One radiologist evaluated tumor-related MRI features, including the capsule contact length (CCL) of lesions, frank extraprostatic extension (EPE), apex abutting, etc. Binary logistic regression and decision tree analysis were used to select risk features for PSM. The area under the curve (AUC), sensitivity, and specificity of different systems were calculated. The interreader agreement of the scoring systems was evaluated using the kappa statistic. RESULTS: There were 29.8% (42/141) and 36.4% (32/88) of patients who had PSM in the derivation and validation cohorts, respectively. The first grading system was proposed (mrPSM1) using two imaging features, namely, CCL ≥ 20 mm and apex abutting, and then updated by adding frank EPE (mrPSM2). In the derivation group, the AUC was 0.705 for mrPSM1 and 0.713 for mrPSM2. In the validation group, our grading systems showed comparable AUC with Park et al.'s model (0.672-0.686 vs. 0.646, p > 0.05) and significantly higher specificity (0.732-0.750 vs. 0.411, p < 0.001). The kappa value was 0.764 for mrPSM1 and 0.776 for mrPSM2. Decision curve analysis showed a higher net benefit for mrPSM2. CONCLUSION: The proposed grading systems based on MRI could benefit the risk stratification of PSM and are easily interpretable. CRITICAL RELEVANCE STATEMENT: The proposed mrPSM grading systems for preoperative prediction of surgical margin status after radical prostatectomy are simplified compared to a previous model and show high specificity for identifying the risk of positive surgical margin, which might benefit the management of prostate cancer. KEY POINTS: ⢠CCL ≥ 20 mm, apex abutting, and EPE were important MRI features for PSM. ⢠Our proposed MRI-based grading systems showed the possibility to predict PSM with high specificity. ⢠The MRI-based grading systems might facilitate a structured risk evaluation of PSM.
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We present a 1 × 1 multimode optical switch for E11, E21, E12, and E22 modes based on cascaded Mach-Zehnder interferometer (MZI) waveguides, where the primary MZI is used to split E11, E21, E12, and E22 modes into E11 or E12 mode and then couple back to the original mode at the output, and the secondary MZIs are the modulation arms of the primary MZI. In addition, the secondary MZIs are designed to be mode-insensitive for switching E11 and E12 modes simultaneously. As a proof of concept, we fabricate the device with polymer material to achieve thermo-optic switching for the four modes. Our experimental device exhibits the extinction ratios of larger than 10.2â dB with a power consumption of 5.5â mW and response times of less than 1.28â ms for each mode. The presented device can be widely applied in mode-division multiplexing (MDM) systems where multimode switching is needed.
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In this paper, we demonstrate a broadband Mach-Zehnder interferometer optical switch based on polycrystalline silicon (poly-Si), which enables the development of multilayer photonics integrated circuits. The poly-Si is deposited under a low temperature of 620 °C to avoid unexpected thermal stress and influence on optoelectronic performance. By introducing a π/2 phase shifter and a push-pull configuration, the switch achieved low power consumption and loss caused by carrier plasma absorption (CPA). The switch operates effectively in both "Bar" and "Cross" states at voltages of -3.35â V and 3.85â V. The power consumptions are 7.98â mW and 9.39â mW, respectively. The on-chip loss is 5.9 ± 0.4â dB at 1550â nm, and the crosstalk is below -20â dB within the C-band. The switch exhibits a 10%-90% rise time of 7.7 µs and a 90%-10% fall time of 3.4 µs at 1550â nm. As far as we know, it is the first demonstration of a poly-Si switch on an 8-inch wafer pilot-line. The low-temperature deposited poly-Si switch is promising for multilayer active photonic devices and photonic-electronic applications.
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BACKGROUND: Effective communication is a crucial component of radiology resident training, and many different aspects need to be explored when teaching and evaluating communication skills. To ensure that radiology residents' communication skill levels can be measured accurately, a standardized evaluation tool has been introduced. In twenty hospitals in Beijing, simulation videos have been developed as a way to assess the communication skills of radiology residents during their certification exams, to minimize evaluating biases. This study aims to assess the performance of a simulation video model in evaluating communications skills compared to the standard patient model. METHODS: This is a retrospective observational study. The performance of standard patient and simulation video models was evaluated through an eight-year examination of communication skills in radiology residents. From 2014 to 2021, communications skill tests were administered to 1003 radiology residents in 20 hospitals in Beijing. The standardized patient (SP) model was applied in 2014, and simulation videos were used from 2015 to 2021. The difficulty and discrimination radio of the tests were evaluated. The subjective survey for candidates on two models of communication skills evaluation was performed and analyzed. RESULTS: The simulation video model evaluation demonstrated stable difficulty (ranging from 0.92 to 0.98) and discrimination ratio (ranging from 0.37 to 0.49), except for minor exceptions of discrimination in 2019 (0.58) and 2020 (0.20). Furthermore, the Kruskal-Wallis H test revealed no significant differences in average scores between 2016 (93.9 ± 4.6) and 2018 (94.5 ± 4.2), 2016 and 2019 (97.3 ± 3.9), 2017 (97.0 ± 5.6) and 2019, 2017 and 2020 (97.7 ± 4.7), as well as 2019 and 2020 exams (all p ≥ 0.05). In addition, candidates who responded to the survey preferred the simulation video model (with a 77.2% response rate), with 62.7% choosing it over the SP model for communication skills evaluation. CONCLUSION: The simulation video demonstrated a stable and better acceptable construct for assessing radiology residents' communication skills.
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Radiologists , Radiology , Humans , Certification , Computer Simulation , HospitalsABSTRACT
A broadband mode-independent thermo-optic (TO) switch using the total-internal-reflection (TIR) effect is proposed and experimentally demonstrated on a polymer waveguide platform. By optimizing geometric parameters of the TIR switch, a mode-independent TO switching function with a large bandwidth and extinction ratio can be realized for E11, E12, and E21 modes. The measurement results show an extinction ratio larger than 18.1â dB with a driving power of 160â mW for each mode over the wavelength range of 1500-1620â nm. The designed structure can also be cascaded to form a 1 × N switch network for mode-division multiplexing (MDM) systems, which greatly improves the network flexibility.
Subject(s)
Eye , PolymersABSTRACT
Information encryption technique has broad applications in individual privacy, military confidentiality, and national security, but traditional electronic encryption approaches are increasingly unable to satisfy the demands of strong safety and large bandwidth of high-speed data transmission over network. Optical encryption technology could be more flexible and effective in parallel programming and multiple degree-of-freedom data transmitting application. Here, we show a dual-layer optical encryption fluorescent polymer waveguide chip based on optical pulse-code modulation technique. Fluorescent oligomers were doped into epoxy cross-linking SU-8 polymer as a gain medium. Through modifying both the external pumping wavelength and operating frequency of the pulse-code modulation, the sender could ensure the transmission of vital information is secure. If the plaintext transmission is eavesdropped, the external pumping light will be switched, and the receiver will get warning commands of ciphertext information in the standby network. This technique is suitable for high-integration and high-scalability optical information encryption communications.