Enhancement Of Peak Intensity Research Articles

Single-unit metalens integrated micro light-emitting diodes

Metalenses, characterized by their discontinuous local phase shifts, are optically analogous to macroscopic curved lenses but are flat and scaled down to micrometer dimensions. Their compactness and compatibility with semiconductor manufacturing processes facilitate monolithic integration into existing optical devices. Here, we report on the integration of metalenses with micro light-emitting diodes (μ-LEDs), resulting in enhanced extraction efficiency and directionality. The metalenses were composed of identical nanohole units, each 150 nm in diameter, strategically arranged to induce desired local phase shifts at specific coordinates by varying the density of these units. Both simulated and experimental results demonstrated that these easy-configuration metalenses effectively focused a plane wave at a predetermined spot and collimated a diverging light source at the focal spot, exemplifying optical reciprocity. When integrated with ultraviolet (λ = 390 nm) 60 μm-sized μ-LEDs, the metalenses significantly improved device performance, exhibiting a 338% enhancement in peak intensity and a ±8° reduction in beam divergence compared to an unpatterned μ-LED. We believe that metalens-integrated μ-LEDs with high brightness, directionality, and resolution are optimally suited for near-eye applications, including virtual reality and augmented reality displays.

Investigation of structural and optical properties of ZnTiO3 thin films irradiated with 50 MeV oxygen ions

This paper aims to investigate the effects of high-energy ion irradiation on the structural, morphological, optical, and luminescent characteristics of ZnTiO3 (ZTO) films. ZTO films were grown on silicon and quartz substrates via RF magnetron sputtering in pure argon ambiance and annealed at 800 °C for crystallization. The annealed (pristine) samples were irradiated with 50 MeV oxygen ions at three distinct fluences: 1 × 1012, 5 × 1012, and 1 × 1013 ions/cm2. X-ray diffraction (XRD) data demonstrates that the intensity of highly oriented (311) peak first increases with fluence up to 5 × 1012 and then decreases at 1 × 1013 ions/cm2. The root mean square roughness (RMS) increases initially from 8.22 (pristine) to 9.10 nm (1 × 1012 ions/cm2) and decreases to 8.25 nm for 1 × 1013 ions/cm2 fluence. Transmittance spectra indicate an enhancement in the transmission of irradiated films. The calculated band gap of pristine and irradiated films lies in the range of 3.93–3.84 eV. X-ray photoelectron spectroscopy (XPS) analysis reveals a reduction in oxygen vacancies up to a fluence of 5 × 1012 and then rises at 1 × 1013 ions/cm2. The enhancement of peak intensity is observed in photoluminescence (PL) spectra on increasing the ion fluence due to a reduction in the non-radiative recombination centers.

High-frame-rate contrast-enhanced ultrasound to differentiate between clear cell renal cell carcinoma and angiomyolipoma

BackgroundTo investigate the diagnostic efficacy of high-frame-rate contrast-enhanced ultrasound (H-CEUS) in differentiating between clear cell renal cell carcinoma (CCRCC) and angiomyolipoma (AML).MethodsA retrospective study was performed on the clinical data of 79 patients diagnosed with CCRCC and 31 patients diagnosed with AML at the First Affiliated Hospital of Nanchang University between October 2022 and December 2023. Conventional ultrasound (US) and H-CEUS examinations were conducted on all patients prior to surgery, dynamic images were recorded from the US, and the qualitative and quantitative parameters of H-CEUS were collected. The t-test, χ² test and non-parametric Mann-Whitney test were employed to assess differences in clinical data, US characteristics, and qualitative and quantitative parameters of H-CEUS between the CCRCC and AML groups. The independent risk factors of CCRCC were identified using binary logistic regression. The receiver operator characteristic (ROC) curve was constructed to evaluate the diagnostic effectiveness of clinical + US and H-CEUS in differentiating between CCRCC and AML.ResultsThe CCRCC group and the AML group exhibited significant differences in patient gender, operation mode, nodular echo, and nodule blood flow (χ²=11.698, -, -,=10.582; P<0.001, <0.001, <0.001, and = 0.014, respectively). In addition, the H-CEUS qualitative analysis demonstrated significant differences between the AML group and the CCRCC group with respect to enhancement mode, regression mode, peak intensity, enhancement uniformity, no enhancement, and presence or absence of pseudocapsule (χ²=41.614, -, -, = 2.758, = 42.099, -; P<0.001, <0.001, <0.001, 0.097, <0.001, and <0.001, respectively). The Arrival time (AT) in the CCRCC group was significantly shorter than that in the AML group, as determined by quantitative analysis of H-CEUS (Z=-3.266, P = 0.001). Furthermore, the Peak intensity (PI), Ascent slope (AS), and The area under the curve (AUC) exhibited significantly higher values in the CCRCC group compared to the AML group (Z=-2.043,=-2.545,=-3.565; P = 0.041, = 0.011, and <0.001, respectively). Logistic regression analysis indicated that only gender, nodule echo, the pseudocapsule, AS, and AUC of H-CEUS were independent risk factors of CCRCC. The ROC curve revealed that combining gender and nodule echo yielded a sensitivity of 92.4%, specificity of 64.5%, and an AUC of 0.847 in distinguishing between CCRCC and AML. When combining the H-CEUS parameters of pseudocapsule, AS, and AUC, the sensitivity, specificity, and AUC for distinguishing between CCRCC and AML were 84.8%, 96.8%, and 0.918, respectively. No statistically significant difference was observed in the diagnostic effectiveness of the two methods (Z=-1.286, P = 0.198). However, H-CEUS demonstrated better AUC and specificity.ConclusionsH-CEUS enhances the sensitivity and specificity of differentiating between CCRCC and AML by improving the temporal resolution, offering a more precise diagnostic foundation for identifying the most appropriate therapy for patients.

Graphene oxide-coated metallic nanotube array as a surface-enhanced Raman scattering (SERS) substrate

This paper presents a highly-ordered metallic nanotube array (MeNTA) coated with graphene oxide (GO) to serve as a surface-enhanced Raman scattering (SERS) substrate. The MeNTA was fabricated using a top-down wafer-scale lithographic and sputter-deposition process, after which a thin layer of GO was deposited uniformly via dip coating. Scanning electron microscopy revealed that GO dip coating did not mar the highly ordered periodic structures on the MeNTA substrate. Raman scattering spectra of Rhodamine 6G (R6G) molecules revealed that coating MeNTA substrates with GO enhanced peak intensity by as much as 2.9 times. Among the substrates examined in this study, the Ag GO MeNTA presented the strongest SERS behavior, with a detection limit of 10−8 M and enhancement factors of 5.38 × 105 for R6G and 2.23 × 105 for Crystal Violet (CV). The uniform distribution of GO and array of periodic structures returned highly consistent (i.e., reproducible) analyte Raman signals, with a relative standard deviation of 12.7 % for R6G and 9.3 % for CV and excellent linear relationship between Raman signal intensity and analyte concentration (R2 = 0.9974 for R6G, 0.9844 for CV).

Growth of β-Ga2O3 nanostructures by thermal oxidation of GaN-on-sapphire for optoelectronic devices applications

Heterostructures of wide-bandgap semiconductors, like β-Ga2O3/ GaN, are being used in many high-power, high-frequency electronic and optoelectronic devices. This paper presents the growth of β-Ga2O3 thin film and nanostructures by thermally oxidizing (at 1000 °C) the planar and nano-structured GaN surfaces respectively. The nano-structures of GaN (having 300–500 nm long vertical nano-kinks) are fabricated by metal-assisted chemical etching of GaN surface for 1–2 hours. The thermally grown β-Ga2O3 samples are polycrystalline. The chemical analysis of the samples using X-ray photoelectron spectroscopy (XPS) showed enhancement of Ga-O peak intensity (at 20.21–20.3 eV) at the expense of the Ga-N peak intensity (at 19.2–19.7 eV) in the thermal oxidation process. The O1s XPS spectra of the oxidized samples exhibited prominent signature of O2- ions (530.7–530.9 eV) representing the formation of Ga2O3 with presence of adsorbed hydroxyl group at the surface (532.2 – 532.4 eV). The valance band XPS spectra disclosed the formation of an additional Ga(4 s)–O(2p) hybridization energy state, and the valence band maxima increased from 2.3 eV to 3.25 eV. The Raman spectra of the oxidized samples exhibited multiple Ag and Bg vibrational modes of β-Ga2O3 along with intense E2(high), A1(LO) modes of GaN. The time-resolved photoluminescence spectra of the samples demonstrated fast transition of charge carriers from excited state to ground state with 460–820 pico-seconds average career lifetime.

Optical analysis of aligned Ni nanowire arrays with different degree of oxidation for terahertz polarizer application

The optical properties of aligned nickel nanowire arrays (NiNWAs) with different degrees of oxidation for terahertz (THz) polarizer applications have been investigated by using THz time-domain spectroscopy. In frequency-domain spectra, the full width at half maxima of transmitted peaks was broadened and the peak positions have a blue shift with increasing oxidation levels, besides the enhancement in peak intensity. It is indicated that the oxidation of Ni nanowires (NWs) has a significant influence on the interaction between Ni NWs and THz wave. The transmittance of the aligned NiNWAs increases with annealing temperature increasing. Conversely, the degree of polarization and extinction ratio (ER) decreases. A corresponding relationship between the change of ER and degree of oxidation is summarized by means of thermogravimetric analysis. The change of ER for the annealing sample with the degree of oxidation of 0.507% is 27.32%, which induced the polarization properties of aligned NiNWAs to be sensitive to the oxidation of Ni NWs. These findings can provide new positive features in the development of future polarization-based device applications for THz electronics and photonics.

Rotational Distributions and Imaging of Singlet O2 Following Spin-Forbidden Photodissociation of O3.

We report REMPI spectra and velocity-mapped ion images of the O2(a1Δg) and (b1Σg+) fragments arising from the spin-forbidden photodissociation of O3 near 320 and 330 nm. The O2(a1Δg, v = 0) REMPI spectrum following a 320 nm dissociation shows enhanced peak intensity for the odd rotational states relative to the even states, which is the opposite of the trend observed by Gunthardt et al. ( J. Chem. Phys. 2019, 151, 224302) for spin-allowed dissociation at 266 nm but is consistent with the couplings between the B state and 3A' and 3A″ states calculated by Grebenshchikov and Rosenwaks ( J. Phys. Chem. A 2010, 114, 9809-9819). There are no significant differences between the ion image angular distributions of fragments in odd and even rotational states, which indicates a cold distribution of O3 and supports the explanation that the alternation in peak intensities results from a difference in the couplings. Quantitative analysis of the image angular distributions was limited due to the single laser polarization geometry accessible in one-color experiments. Radial distributions of the 320 nm images indicate a broad rotational distribution, evidenced in bimodal speed distributions with peaks corresponding to both high (j = 35-43) and low (j = 17-20) rotational states. The REMPI spectrum of O2(a1Δg) near 330 nm was collected, and while quantitative population analysis is difficult because of the perturbed resonant state, the spectrum clearly supports a broad rotational distribution as well, consistent with the images collected at 320 nm. A 2D-REMPI spectrum was collected following dissociation of O3 near 330 nm, which showed evidence of contributions from O2 fragments in both the a1Δg and b1Σg+ states. The rotational distribution for the O2(b1Σg+, v = 0) product peaks at j = 32 and is narrower than that of the O2(a1Δg) fragment, consistent with distributions reported by O'Keeffe et al. at longer dissociation wavelengths ( J. Chem. Phys. 2002, 117, 8705-8709). At smaller radii in the 2D-REMPI spectrum, there is additional signal assigned to v = 1-4 of O2(b1Σg+), with rotational distributions similar to v = 0. The vibrational distribution of the O2(b1Σg+) fragment peaks at v = 0, with populations monotonically decreasing with increasing vibrational state. Ion image angular distributions of the O2(b1Σg+) fragment and the corresponding anisotropy parameters are also reported.

Pre-operative Prediction of Invasiveness in Renal Cell Carcinoma: The Role of Conventional Ultrasound and Contrast-Enhanced Ultrasound

It is known that in patients with renal cell carcinoma (RCC), the invasiveness of the tumor is closely related to the treatment and prognosis. Currently, histologic diagnosis of RCC is typically established after surgical removal of tumors or after biopsy. The use of non-invasive imaging modalities to predict the invasiveness of RCC is of great clinical value, particularly before surgery. In this study, the differences in conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) features between invasive and non-invasive RCC were analyzed with the aim of providing more accurate and valuable information for diagnosis and treatment to clinically optimize the treatment plan in a non-invasive manner and improve the prognosis of patients. Conventional US and CEUS features of 163 patients (total of 164 RCCs), obtained from the Lanzhou University Second Hospital in the period ranging from March 2021 to September 2022, were retrospectively analyzed. Patients were categorized into two groups: invasive group (n=44) and non-invasive group (n=120), with surgical pathology as reference standard. Receiver operating characteristic curves were drawn to evaluate the feasibility of differentiation. The possibility of an intrarenal lesion/kidney ratio >50% in the invasive group (13/44, 29.5%) was significantly higher than that in the non-invasive group (8/120, 6.7%) (p < 0.001). The absence of perilesional rim-like enhancement was more likely to imply invasive RCC (30/44, 68.2%) than non-invasive RCC (100/120, 83.3%) (p=0.049) and was an independent predictor of invasive RCC. As for CEUS quantitative features, there were statistically significant differences in peak intensity (p=0.009) or peak enhancement (p=0.010), taking the largest range of lesion as the region of interest. Conventional US and CEUS features may help in the differentiation of invasive RCC from non-invasive RCC and have potential application value in the pre-operative prediction of RCC invasiveness.

Plasmon-enhanced photoluminescence and Raman spectroscopy of silver nanoparticles grown by solid state dewetting

The growth of the metallic nanoparticles (NPs) on the solid substrate with the desired shape and size is a critical issue for application of these NPs in solid-state devices. Solid state dewetting (SSD) technique is simple, low cost and can be used to fabricate the metallic NPs with control on the shape and size on different substrates. In this work, silver NPs (Ag NPs) were grown on corning glass substrate by SSD of silver precursor thin film deposited at different substrate temperatures by RF sputtering. The influence of the substrate temperature on the growth of Ag NPs and their several properties like localized surface plasmon resonance (LSPR), photoluminescence (PL), and Raman spectroscopy is studied. The size of the NPs was found to vary from 25 nm to 70 nm with the variation in substrate temperature from room temperature (RT) to . For the RT films, the LSPR peak position of Ag NPs is around 474 nm. A red shift in LSPR peak for films deposited at higher temperature is observed due to change in the particle size and interparticle separation. Photoluminescence spectra suggests the presence of two photoluminescence bands at 436 and 474 nm corresponding to Ag NPs radiative interband transition and LSPR band. An intense Raman peak was observed at 1587 cm−1. Enhancement in PL peak intensity and Raman peak intensity is found to be in accordance with the LSPR of Ag NPs.

Diagnostic value of pseudocapsule ring hyperenhancement in contrast-enhanced ultrasound in renal focal lesions.

To investigate the diagnostic value of pseudocapsule ring hyperenhancement in contrast-enhanced ultrasound (CEUS) of focal renal lesions. Ninety eligible patients admitted were selected as the study subjects. The incidence rate of annular hyperenhancement in different benign and malignant focal lesions during angiography and the shape of annular enhancement were counted. The correlation between the occurrence of benign and malignant renal tumors and annular hyperenhancement and unenhanced areas was also analyzed. Capsule enhancement was observed in 56 cases, including 50 cases of malignant tumors (89.3%, 50/56) and 6 cases of benign tumors (10.7%, 6/56). Pearson correlation analysis showed that renal malignancy was positively associated with the occurrence of pseudocapsule ring hyperenhancement (γ = 0.489, P < 0.001). Benign and malignant renal tumors were positively correlated with the occurrence of non-enhancing areas (γ = 0.215, P = 0.042). The thickness and peak intensity of pseudocapsule ring enhancement in renal malignant tumors were significantly higher than those in benign tumors (all P < 0.001), while the time to peak was significantly lower than that in benign tumors (P < 0.001). The results of receiver operating characteristic (ROC) curve showed that the ring enhancement thickness, time to peak, and area under ROC curve of peak intensity of tumor reached more than 0.9. In CEUS, the pseudocapsule of focal renal lesions is a characteristic feature of renal malignant tumors, which can be used as a differential basis for benign and malignant tumors to improve the accuracy of benign and malignant renal tumors.

Bismuth oxybromide based novel substrate for surface enhanced Raman spectroscopy

Bi24O31Br10 powders were prepared through calcination at 500 ⁰C by chemical precipitation method. Relative Raman peak intensity enhancement after annealing at different temperature was observed along with new characteristic feature that confirm the phase stability of Bi24O31Br10 powders. The as-synthesized sample exhibited excellent SERS activity with rhodamine B (RhB), 4-nitrophenol (4-NP) and methyl orange (MO) as probe molecules. The minimum detectable concentration was 20 µM for RhB, 100 µM for 4-NP and 100 µM for MO. Moreover, the remarkable enhancement was obtained with the ethanol solvent as compared to water for the SERS detection of RhB with 785 nm laser excitation. Multi-molecular detection was also successfully carried out.

Electrochemical Sensing Platform Based on Functionalized Multi-Walled Carbon Nanotubes and Metal Oxide for the Detection and Degradation Studies of Orange II Dye.

Textile industry effluents are heavily contaminated with dyes. The discharge of these toxic dyes into waterbodies poses a serious threat to aquatic flora and fauna. The ultimate entrance of these toxins from thereon into the food chain affects the primary and secondary consumers. Therefore, the adoption of a sustainable solution for protection against the detrimental effects associated with adulterated water is an immediate need of the hour. To address the severity of the issue, the present work aims to design an electrochemical sensing platform by modifying the glassy carbon electrode (GCE) with zinc oxide nanoparticles and amino group-functionalized multi-walled carbon nanotubes (NH2-fMWCNTs) for the detection of Orange II, which is a toxic azo dye. Zinc oxide nanoparticles facilitate electron transfer between the transducer and the analyte. While, the positively charged NH2-fMWCNTs in acidic medium help in preconcentration of negatively charged analyte molecules at the electrode/electrolyte interface. The modification of the GCE catalyzed the oxidation of Orange II, as evidenced by the negative shift of the oxidation potential and enhancement in peak current intensity. Square wave voltammetry was used to optimize various experimental conditions, such as the supporting electrolyte, pH of the electrolyte, deposition potential, and deposition time for the best performance of the designed sensor. Under the optimized conditions, the detection limit and quantification of the designed sensor were found to be 0.57 and 1.92 nM, respectively. The catalytic degradation studies of Orange II was shown to be facilitated by titanium dioxide, which acted as a photocatalyst. The addition of hydrogen peroxide further promoted the extent and rate of degradation of dye. The breakdown of Orange II was probed by the designed sensing platform electrochemically and also by UV–visible spectroscopy. The dye degraded up to 92% by following pseudo-first-order kinetics.

Enhancing oxygen/moisture resistance of quantum dots by short-chain, densely cross-linked silica glass network

Quantum dots (QDs) are facing significant photoluminescence degradation in moisture environment. In QDs-silicone composites, the poor water resistance of silicone matrix makes it easy for water and oxygen molecules to erode QDs. To tackle this issue, we proposed a new QDs protection strategy by introducing short-chain silica precursors onto the QDs’ surface, so that a dense silica passivation layer could be formed onto the QDs nanoparticles. Sol-gel method based on 3-aminopropyl triethoxysilane (APTES), 3-mercaptopropyl trimethoxysilane (MPTMS), and 3-mercaptopropyl triethoxysilane (MPTES) were adopted to prepare the uniform and crack-free QDs-silica glass (QD-glass). Because of the crosslinking of short-chain precursors, the formed silica glass possesses 38.6% smaller pore width and 68.6% lower pore volume than silicone, indicating its denser cross-linked network surrounding QDs. After 360 h water immersion, the QDs-glass demonstrated a 6% enhancement in red-light peak intensity, and maintained a stable full width at half maximum (FWHM) and peak wavelength, proving its excellent water-resistant ability. However, the conventional QDs-silicone composites not only showed a decrease of 75.3% in red-light peak intensity, but also a broadened FWHM and a redshifted peak wavelength after water immersion. QDs-glass also showed superior photostability after 132 h exposure to blue light. Red-light peak intensity of QDs-glass remained 87.3% of the initial while that of QDs-silicone decreased to 19.8%. And the intensity of QDs-glass dropped to 62.3% of that under 20 °C after thermal treatment of 160 °C. Besides, under increasing driving currents, the light conversion efficiency drop of QDs-glass is only one fifth that of QDs-silicone. Based on the QDs-glass, the white light-emitting diodes was achieved with a high luminous efficiency of 126.5 lm W−1 and a high color rendering index of 95.4. Thus, the newly proposed QD-glass has great significance in guaranteeing the working reliability of QDs-converted devices against moisture and high-power environment.

Effect of CuS buffer layer on the structural and optical properties of TeO2 nanowires: a comparative study

The current work concerns with the effects of cupper sulfide (CuS) buffer layer on morphological, structural and optical properties of tellurium dioxide (TeO2) nanostructured thin films synthesized by vapor transport method. Single crystalline tetragonal TeO2 crystallographic phase with enhanced peak intensity and crystallinity for CuS/TeO2 film are observed by x-ray diffraction analysis. Scanning electron microscopy examinations revealed small rod-like morphology for TeO2 and randomly oriented nanowires morphology for CuS/TeO2 samples. The estimated optical band gap energies were 3.78 and 3.63 eV for TeO2 and CuS/TeO2 nanostructured films, respectively. The photoluminescence of CuS/TeO2 film was enhanced and red-shifted from 450 to 455 nm by the presence of CuS layer. The effective charge carrier life times were 0.14 ns and 1.92 ns for TeO2 and CuS/TeO2 films, respectively. These results could be beneficial for optoelectronic devices such as light emitting devices.

Evaluating Tumor-Infiltrating Lymphocytes in Breast Cancer: The Role of Conventional Ultrasound and Contrast-Enhanced Ultrasound.

Tumor-infiltrating lymphocytes (TILs) have emerged as an efficient biomarker predicting treatment response and prognosis of breast cancer (BC). This study aimed to evaluate the association between conventional ultrasound and contrast-enhanced ultrasound (CEUS) imaging features with TIL levels in invasive BC patients. We retrospectively included 267 women with invasive BC who had undergone conventional ultrasound and CEUS. Patients were divided into low (≤10%) and high (>10%) TIL groups. Conventional ultrasound and CEUS features were analyzed by two sonographers. The associations between the TIL levels and imaging features were evaluated. Of the 267 patients, 122 with high TILs and 145 with low TIL levels. High TIL tumors were more likely to have a circumscribed margin, oval or round shape, and enhanced posterior echoes on ultrasonography (p < 0.05). In contrast, low TIL tumors were more likely to have an irregular shape, un-circumscribed, indistinct and spiculated margin (p < 0.05). In CEUS, high TIL tumors showed a more regular shape, clearer margin, more homogeneous enhancement and higher peak intensity (PI) value (p < 0.05). Logistic analysis indicated that shape, posterior features, PI, and enhanced homogeneity were independent predictors for high TIL tumors. The model combined the four independent predictors have a moderate performance in predicting high TIL tumors with AUC 0.79, sensitivity 0.72, and specificity 0.78. Conventional ultrasound and CEUS features were associated with TIL levels in invasive BC. Consequently, the results suggested that preoperative conventional ultrasound and CEUS may be a useful noninvasive imaging biomarker for individualized treatment decisions.

A Practical CEUS Thyroid Reporting System for Thyroid Nodules.

Background The role of contrast-enhanced US (CEUS) in reducing unnecessary biopsies of thyroid nodules has received little attention. Purpose To construct and externally validate a thyroid imaging reporting and data system (TI-RADS) based on nonenhanced US and CEUS to stratify the malignancy risk of thyroid nodules. Materials and Methods This retrospective study evaluated 756 patients with 801 thyroid nodules who underwent nonenhanced US, CEUS, and fine-needle aspiration and received a final diagnosis from January 2018 to December 2019. Qualitative US features of the thyroid nodules were analyzed with univariable and multivariable logistic regression to construct a CEUS TI-RADS. The CEUS TI-RADS was validated with use of internal cross-validation and external validation. Results A total of 801 thyroid nodules in 590 female (mean age, 44 years ± 13) and 166 male (mean age, 47 years ± 13 [SD]) patients were included. Independent predictive US features included nodule composition at CEUS, echogenicity, nodule shape, nodule margin, echogenic foci, extrathyroidal extension, enhancement direction, peak intensity, and ring enhancement. The CEUS TI-RADS showed a higher area under the receiver operating characteristic curve of 0.93 (95% CI: 0.92, 0.95; P < .001 in comparison with all other systems), a biopsy yield of malignancy of 66% (157 of 239 nodules), and an unnecessary biopsy rate of 34% (82 of 239 nodules). In the external validation, the area under the receiver operating characteristic curve, biopsy yield of malignancy, and unnecessary biopsy rate of CEUS TI-RADS were 0.89 (95% CI: 0.84, 0.92), 61% (65 of 106 nodules), and 39% (41 of 106 nodules) for the first external validation set and 0.90 (95% CI: 0.85, 0.94), 57% (56 of 99 nodules), and 43% (43 of 99 nodules) for the second external validation set. Conclusion A contrast-enhanced US (CEUS) thyroid imaging reporting and data system was created with thyroid nodule malignancy risk stratification according to the simplified regression coefficients of nonenhanced US and qualitative features of CEUS. Clinical trials registration no. ChiCTR2000028712 Published under a CC BY 4.0 license. Online supplemental material is available for this article.

The effect of RF plasma power on remote plasma sputtered AZO thin films

Aluminium-doped ZnO (AZO) thin films were deposited by remote plasma sputtering of a ZnO:Al2O3 98:2 wt% ceramic target in a pulsed DC configuration. The target power was kept constant at 445 W and the RF plasma power was varied between 0.5 and 2.5 kW. The as-deposited AZO thin films exhibited an optimum resistivity of 6.35 × 10−4 Ω·cm and optical transmittance of 92% at a RF plasma power of 1.5 kW. The thin film microstructure, chemical composition, and residual stress were investigated using SEM, RBS, XPS and XRD. Accurate determination of the chemical composition and correct interpretation of GIXRD data for AZO thin films are a particular focus of this work. The AZO layer thickness was 500–700 nm and Al content in the range of 2.3–3.0 at.%, determined by RBS. The AZO thin films exhibited a strong (002) preferential orientation and grain sizes between 70 and 110 nm. The (103) peak intensity enhancement in GIXRD is proven to be a result of the strong (002) preferential orientation and GIXRD geometrical configuration rather than a change in the crystallite orientation at the surface. XPS depth profiles show preferential sputtering of O and Al using a 500 eV Ar+ beam, which can be reduced, but not eradicated using an 8 keV Ar150+ beam. The preferential sputtering can be successfully modelled using the simulation software TRIDYN. A plasma power of 1.5 kW corresponds to a highly ionised plasma and various microstructural and compositional factors have all contributed to the optimum low resistivity occurring at this plasma power. The grain size exhibits a maximum in the 1.25–1.5 kW range and there is improved (002) orientation, minimising grain boundary scattering. The highest carrier concentration and mobility was observed at the plasma power of 1.5 kW which may be associated with the maximum in the aluminium doping concentration (3.0 at.%). The lowest residual stress is also observed at 1.5 kW.

Optical Pulse Compression Assisted by High‐Q Time‐Modulated Transmissive Metasurfaces

AbstractIn this paper, based on the recently introduced concept of time‐varying media, an alternative approach is presented for controlling the compression ratio of an optical pulse in the near‐infrared regime via two all‐dielectric transmissive metasurfaces consisting of a zigzag array of silicon‐based elliptical nanodisks. Upon introducing in‐plane asymmetries and under normal incidence, the supported symmetry‐protected bound‐state in the continuum resonant mode collapses into two Fano resonances, which can be spectrally overlapped to satisfy the first Kerker's condition. To acquire an amplified signal, the desired chirp is applied to the incident pulse via a purely temporal waveform that modulates the optical response of the first layer, while the required group delay dispersion is imparted to the phase‐modulated pulse by the second metasurface in order to compress its temporal distribution. Following such a configuration, the temporal duration of the output pulse decreases from 25 to 15 ps, leading to a peak intensity enhancement of 50%. On account of time‐varying features of the first metasurface, the instantaneous frequency of the chirped light can be controlled dynamically, giving rise to the active tuning of the peak intensity from 0% up to 200%.

Effect of bismuth surfactant on the structural, morphological and optical properties of self-assembled InGaAs quantum dots grown by Molecular Beam Epitaxy on GaAs (001) substrates

In this work, we have investigated the effect of Bi surfactant on structural, morphological and optical properties of 5 monolayers self-assembled InGaAs quantum dots (QDs) grown on GaAs (001) substrates at various growth temperatures (435, 467 and 495 °C) by Molecular Beam Epitaxy. Two types of InGaAs QDs samples grown with and without exposure to bismuth were studied using Atomic Force Microscopy, Scanning Electron Microscopy, Transmission Electron Microscopy and Photoluminescence (PL). Our results have demonstrated that Bi-mediated growth provides improved control of several properties of InGaAs QDs including an enhancement of the QD PL peak intensity by 1.7 times as compared to InGaAs/GaAs control sample grown without Bi. In addition, a red-shift of the PL peak energy of about 40 meV was also observed when the InGaAs QDs were grown by using Bi evidencing that Bi surfactant affects considerably the size of QDs. Furthermore, the QDs grown with Bi surfactant exhibited a higher degree of size uniformity as demonstrated by the observation of narrower Full Width at Half Maximum (FWHM) of the PL peaks. We have also shown that both Bi surfactant and substrate temperature play an important role to control the density of InGaAs QDs. The QD density decreased from 8.9 × 1010 cm−2 (control sample) to 2.0 × 1010 cm−2 for the sample grown at the lowest temperature of 435 °C under Bi flux. All these approaches to control and improve the properties of self-assembled QDs are important for device applications that require high optical efficiency and low QD density.

Engineering the doping amount of rare earth element erbium in CdWO4: Influence on the electrochemical performance and the application to the electrochemical detection of bisphenol A

Rare earth elements Er doped CdWO4 (Er-CdWO4) nanorods were successfully prepared. The morphology, crystal structure, chemical environments and electrochemical properties of Er-CdWO4 nanomaterials were regulated by changing the doping amount of Er. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) have shown that the introduction of moderate content of Er could optimize the morphology of CdWO4. X-ray diffraction (XRD) results suggested that the larger Er ions partially replaced the Cd ions in CdWO4 nanocrystals and produced favorable lattice gaps and defects around the unit cell. The high-resolution X-ray photoelectron spectroscopy (XPS) of O 1 s and the enhanced peak intensity in electron spin resonance (EPR) declared that the doping of Er generated more oxygen vacancies in Er-CdWO4. Based on the physico-chemical characterizations, 0.5 wt% Er-CdWO4 was confirmed to be the best electrocatalyst within the tested samples, which exhibited the fastest electron transfer performance and the strongest electrocatalytic capacity to BPA. Taking the low-cost and simply prepared Er-CdWO4 with the optimal content of Er as the electrode modifier, a novel electrochemical sensor (Er-CdWO4/CPE) for BPA has been constructed for the first time, which exhibited the wide linear range from 0.01 to 6 μM and the limited detection of 0.003 μM, respectively. Moreover, satisfactory reproducibility, stability and anti-interference performance were also achieved on Er-CdWO4/CPE. Meanwhile, the proposed sensor successfully realized the determination of BPA spiked in local tap water samples.