Preparation and performance of a CsI scintillation screen with a double-period structure based on an oxidized silicon micropore array template.

A structured double-period CsI scintillation screen was successfully developed to improve its detection efficiency based on an oxidized silicon micropore array template with a period value on the order of micro-scale. The structure comprises a main structure along with a sub-structure. The main structure with a period of 8 µm was arranged in a square array consisting of square columnar scintillator units. The micropore walls between the main structure units were purposely fabricated from a SiO2-Si-SiO2 layered structure. The pore walls in commonly used single-structure with a period of 4 µm use the same layered structure composition to obtain a fair comparison. The thickness of both Si and the SiO2 layers was around 0.4 µm. The unique feature of the double structure lies in the even separation of each unit within the main structure into four square columnar scintillator sub-units. These four sub-units within each sub-structure were isolated solely by SiO2 layers with a thickness of approximately 0.8 µm. As a result, the X-ray-induced optical luminescence intensity of the double-structure screen exhibited a 31% increase compared to the corresponding single-structure scintillation screen. In X-ray imaging, a spatial resolution of 109 lp/mm was achieved, which closely matched the results obtained with the single-structure CsI screen. Furthermore, the detective quantum efficiency also displayed a notable improvement.

Ultrafast Decay, Ultrahigh Spatial Resolution, and Stable γ-CuI Single Crystal Treated by Iodine Annealing and SiO2 Coating.

The demand for scintillators with ultrafast decay times, high spatial resolutions, and high stabilities is increasing due to the development of ultrafast hard X-ray detection, hard X-ray imaging, and high-energy physics facilities. γ-CuI single crystals, which exhibit ultrafast luminescence and high stopping power for hard X-rays, hold great promise for such applications. However, slow luminescence and poor stability caused by surface iodine deficiencies hinder the practical use of γ-CuI. Herein, we treated a γ-CuI single crystal by iodine annealing and SiO2 coating and investigated its crystal structure and luminescence properties in detail. Iodine annealing significantly enhanced the near-band-edge emission of the γ-CuI crystal with an ultrafast decay time of less than 1 ns, while completely suppressing the slow luminescence. Moreover, the SiO2 film effectively prevented the oxidation and decomposition of surface iodine, leading to substantial improvement in luminescence stability. The γ-CuI crystal demonstrated an ultrahigh spatial resolution of 1.5 µm in X-ray imaging, highlighting its potential for ultrafast hard X-ray imaging applications. This study provides insight into the growth, optimization, and application of γ-CuI crystals, advancing the field of scintillator materials.

Optimization of SiO2 reflective layer thickness for improving the performance of structured CsI scintillation screen based on oxidized Si micropore array template in X-ray imaging.

Structured scintillation screen based on oxidized Si micropore array template can effectively improve the spatial resolution of X-ray imaging. The purpose of this study is to investigate the effect of SiO2 layer thickness on the light guide and X-ray imaging performance of CsI scintillation screen when the structural period is as small as microns. Cylindrical micropores with a period of 4.3 µm, an average diameter of 3.3 µm and a depth of about 40 µm were prepared in Si wafers. SiO2 layer was formed on the pore walls after thermal oxidation. Increasing SiO2 layer thickness would be beneficial to the propagation of scintillation light along the cylindrical channels. What was not previously anticipated was that the pore size gradually shrank as the SiO2 layer thickened. The pore shrinkage would reduce the filling rate of CsI in the templates and thus would reduce the production of scintillation light. The structured CsI scintillation screens with different SiO2 layer thicknesses were fabricated by filling CsI scintillator into the oxidized silicon micropore array template. The morphology, crystallinity, X-ray excited optical luminescence, and X-ray imaging performance of the screens were studied. The results show that the spatial resolutions of X-ray images measured using the structured CsI scintillation screens with different SiO2 layer thicknesses are close to each other, and they are all about 110 lp/mm. However, the X-ray excited optical luminescence of the screen and detective quantum efficiency of X-ray imaging vary with the thickness of the SiO2 layer. The optimal thickness is about 350 nm.

Body mass index-based predictions and personalized clinical strategies for colorectal cancer in the context of PPPM.

Currently colorectal cancer (CRC) is the third most prevalent cancer worldwide. Body mass index (BMI) is frequently used in CRC screening and risk assessment to quantitatively evaluate weight. However, the impact of BMI on clinical strategies for CRC has received little attention. Within the framework of the predictive, preventive, and personalized medicine (3PM/PPPM), we hypothesized that BMI stratification would affect the primary, secondary, and tertiary care options for CRC and we conducted a critical evidence-based review. BMI dynamically influences CRC outcomes, which helps avoiding adverse treatment effects. The outcome of surgical and radiation treatment is adversely affected by overweight (BMI ≥ 30) or underweight (BMI < 20). A number of interventions, such as enhanced recovery after surgery and robotic surgery, can be applied to CRC at all levels of BMI. BMI-controlling modalities such as exercise, diet control, nutritional therapy, and medications may be potentially beneficial for patients with CRC. Patients with overweight are advised to lose weight through diet, medication, and physical activity while patients suffering of underweight require more focus on nutrition. BMI assists patients with CRC in better managing their weight, which decreases the incidence of adverse prognostic events during treatment. BMI is accessible, noninvasive, and highly predictive of clinical outcomes in CRC. The cost-benefit of the PPPM paradigm in developing countries can be advanced, and the clinical benefit for patients can be improved with the promotion of BMI-based clinical strategy models for CRC.

Influence of the thickness of a SiO2 reflective layer on the performance of a structured CsI(Tl) scintillation screen based on an oxidized Si micropore array template in X-ray imaging.

To obtain better light guidance and optical isolation effects under a limited microcolumn wall thickness, the influence of the thickness of a SiO2 reflective layer on the performance of a structured CsI(Tl) scintillation screen based on an oxidized Si micropore array template in X-ray imaging was simulated. The results show that the SiO2 reflective layer should maintain a certain thickness to achieve good light-guide performance. However, if the template is entirely composed of SiO2, the light isolation performance of the microcolumn wall will be slightly worse. The results provide a basis for optimizing the thickness of SiO2 reflective layer.

Influence of Si wall thickness of CsI(Tl) micro-square-frustums on the performance of the structured CsI(Tl) scintillation screen in X-ray imaging.

To improve the detection efficiency of the structured scintillation screen with CsI(Tl) micro-square-frustums based on oxidized Si micropore array template in the case of a period as small as microns, the influence of Si wall thickness of the CsI(Tl) micro-square-frustums on the performance of the structured screen in X-ray imaging was investigated. The results show that when CsI(Tl) at the bottom of the screen is structured, the detective quantum efficiency (DQE) improves at almost all spatial frequency as the top thickness of the Si wall tSi decreases. However, when CsI (Tl) at the bottom of the screen is not structured, the DQE becomes better at low-frequency and worse at high-frequency as tSi decreases. The results can provide guidance for optimizing tSi according to the comprehensive requirements of detection efficiency and spatial resolution in X-ray imaging.

Alcohol Consumption and Risk of Atrial Fibrillation: A Dose-Response Meta-Analysis of Prospective Studies.

Background: This study aimed to investigate the dose-response association between alcohol consumption and atrial fibrillation (AF) risk. Methods: PubMed, Embase, Cochrane Library, and Web of Science were systematically searched using keywords related to alcohol and AF from the establishment of databases up to 1 March 2021. Prospective studies examining the impact of alcohol on the risk of AF with hazard ratios (HRs) were included. Restricted cubic spline regression was performed to quantify the dose-response relationship between alcohol consumption and AF risk. Results: Thirteen eligible studies were included in the meta-analysis, with a total of 645,826 participants and 23,079 cases of AF. When compared with non-/seldom-drinkers, the pooled adjusted HRs of AF were 1.30 (95% confidence interval [CI]: 1.20-1.41) and 1.00 (95% CI: 0.96-1.05) for high and low alcohol consumption, respectively. Moderate alcohol intake significantly increased the risk of AF in males (HR, 1.21; 95% CI: 1.10-1.33) but not in females (HR, 1.02; 95% CI: 0.91-1.14). The cubic spline regression analysis illustrated that the risk of AF significantly increased with daily alcohol intake in a Non-linear manner (R2 = 0.64, P = 5.785 × 10-12). Conclusion: This study revealed a Non-linearly positive association between alcohol intake and the risk of AF. Low alcohol intake was not associated with the development of AF, whereas moderate alcohol intake significantly increased the risk of AF in males but not in females. Our meta-analysis highlighted that alcohol consumption should be restricted to a low level to reduce the risk of AF.

Diffusion kurtosis imaging as an imaging biomarker for predicting prognosis in chronic kidney disease patients.

BACKGROUND: Renal fibrosis is the strongest prognostic predictor of end-stage renal disease (ESRD) in chronic kidney disease (CKD). Diffusion kurtosis imaging (DKI) is a promising method of magnetic resonance imaging successfully used to assess renal fibrosis in immunoglobulin A nephropathy. This study aimed to be the first to evaluate the long-term prognostic value of DKI in CKD patients. METHODS: Forty-two patients with CKD were prospectively enrolled, and underwent DKI on a clinical 3T MR scanner. We excluded patients with comorbidities that could affect the volume or the components of the kidney. DKI parameters, including mean Kurtosis (K), mean diffusivity and apparent diffusion coefficient (ADC) of kidney cortex were obtained by region-of-interest measurement. We followed up these patients for a median of 43 months and investigated the correlations between each DKI parameter and overall renal prognosis. RESULTS: Both K and ADC values were correlated well with the estimated glomerular filtration rate (eGFR) on recruitment and the eGFR of the last visit in follow-up (P ˂ 0.001). K and ADC values were also well associated with the eGFR slopes in CKD patients, both with the first-last time point slope (P = 0.011 and P ˂ 0.001, respectively) and with the regression slope (P = 0.010 and P ˂ 0.001, respectively). Cox proportional hazard regression indicated that lower eGFR and ADC values independently predicted eGFR loss of ˃30% and ESRD. The receiver operating characteristic analysis showed that K and ADC values were predictable for renal prognosis, and ADC displayed better capabilities for both ESRD [area under the curve (AUC) 0.936, sensitivity 92.31%, specificity 82.76%] and the composite endpoint (eGFR loss ˃30% or ESRD) (AUC 0.881, sensitivity 66.67%, specificity 96.3%). CONCLUSIONS: Renal ADC values obtained from DKI showed significant predictive value for the prognosis of CKD patients, which could be a promising noninvasive technique in follow-up.

Highly sensitive X-ray detector based on a ß-Ga2O3:Fe single crystal.

ß-Ga2O3 semiconductor crystal is of wide band gap and high radiation resistance, which shows great potential for applications such as medical imaging, radiation detections, and nuclear physical experiments. However, developing ß-Ga2O3-based X-ray radiation detectors with high sensitivity, fast response speed, and excellent stability remains a challenge. Here we demonstrate a high-performance X-ray detector based on a Fe doped ß-Ga2O3 (ß-Ga2O3:Fe) crystal grown by the float-zone growth method, which consists of two vertical Ti/Au electrodes and a ß-Ga2O3:Fe crystal with high resistivity. The resistivity of the ß-Ga2O3:Fe crystal exceeds 1012 Ω cm owed to the compensation of the Fe ions and the free electrons. The detector shows short response time (0.2 s), high sensitivity (75.3 µC Gyair -1 cm-2), and high signal-to-noise ratio (100), indicating great potential for X-ray radiation detection.

Performance of a CsI(Tl) scintillation screen with a dual-periodic structure based on an oxidized silicon micropore array template in X-ray imaging.

To address the reduction in the detection efficiency of a structured CsI(Tl) scintillation screen when its structure period reaches the order of microns, a dual-periodic structure of the screen is proposed. The special feature of the dual structure is that each unit of the primary structure is divided equally into either four or nine square column-shaped scintillation sub-units. The sub-units are separated only by SiO2 layers to form a secondary structure. The results show that the performance of a dual-structure CsI(Tl) screen in X-ray imaging is much better than that of a corresponding single-structure screen.

Light output enhancement of scintillators by using mixed-scale microstructures.

Scintillators play an important role in the field of nuclear radiation detection. However, the light output of the scintillators is often limited by total internal reflection due to the high refractive indices of the scintillators. Furthermore, the light emission from scintillators typically has an approximately Lambertian profile, which is detrimental to the collection of the light. In this paper, we demonstrate a promising method to achieve enhancement of the light output from scintillators through use of mixed-scale microstructures that are composed of a photonic crystal slab and a microlens array. Simulations and experimental results both show significant improvements in the scintillator light output. The X-ray imaging characteristics of scintillators are improved by the application of the mixed-scale microstructures. The results presented here suggest that the application of the proposed mixed-scale microstructures to scintillators will be beneficial in the nuclear radiation detection field.

Improved light output from thick ß-Ga2O3 scintillation crystals via graded-refractive-index photonic crystals.

ß-Ga2O3 is a promising candidate as a fast scintillation crystal for radiation detection in fast X-ray imaging and high-energy physics experiments. However, total internal reflection severely limits its light output. Conventional photonic crystals can improve the light output, but such improvement decreases dramatically with increased scintillator thickness due to the strong backward reflection by the photonic crystals. Here, graded-refractive-index photonic crystals composed of nanocone arrays are designed and fabricated on the surfaces of ß-Ga2O3 crystals with various thicknesses. Compared to the conventional photonic crystals, there is still an obvious light output improvement by using the graded-refractive-index photonic crystals when the thickness of the crystals is increased by three times. The effect of thickness on the improved light output is investigated with numerical simulations and experiments. Overall, the graded-refractive-index photonic crystals are beneficial to the improvement of light output from thick scintillators.

Hollow nanosphere arrays with a high-index contrast for enhanced scintillating light output from ß-Ga2O3 crystals.

ß-Ga2O3 is a new type of fast scintillator with potential applications in medical imaging and nuclear radiation detection with high count-rate situations. Because of the severe total internal reflection with its high refractive index, the light extraction efficiency of ß-Ga2O3 crystals is rather low, which would limit the performance of detection systems. In this paper, we use hollow nanosphere arrays with a high-index contrast to enhance the light extraction efficiency of ß-Ga2O3 crystals. We can increase the transmission diffraction efficiency and reduce the reflection diffraction efficiency through controlling the refractive index and the thickness of the shell of the hollow nanospheres, which can lead to a significant increase in the light extraction efficiency. The relationships between the light extraction efficiency and the refractive index and thickness of the shell of the hollow nanospheres are investigated by both numerical simulations and experiments. It is found that when the refractive index of the shell of the hollow nanospheres is higher than that of ß-Ga2O3, the light extraction efficiency is mainly determined by the diffraction efficiency of light transmitted from the surface with the hollow nanosphere arrays. When the refractive index of the shell is less than that of ß-Ga2O3, the light extraction efficiency is determined by the ratio of the diffraction efficiency of the light transmitted from the surface with the hollow nanosphere arrays to the diffraction efficiency of the light that can escape from the lateral surface.

High-Performance X-ray Detector Based on Single-Crystal ß-Ga2O3:Mg.

X-ray detection plays an important role in medical imaging, scientific research, and security inspection. Recently, the ß-Ga2O3 single-crystal-based X-ray detector has attracted extensive attention due to its excellent intrinsic properties such as good absorption for X-ray photons, a high breakdown electric field, high stability, and low cost. However, developing a high-performance ß-Ga2O3-based X-ray detector remains a challenge because of the large dark current and the high oxygen vacancy concentration in the crystals. In this paper, we report a high-performance Mg-doped ß-Ga2O3 single-crystal-based X-ray detector with a sandwich structure. The reduced dark current enables the detector to have a high sensitivity of 338.9 µC Gy-1 cm-2 under 50 keV X-ray irradiation with a dose rate of 69.5 µGy/s. The sensitivity is 16-fold higher than that of the commercial amorphous selenium detector. Furthermore, the reduced oxygen vacancy concentration can improve the response speed (<0.2 s) of the detector. The present studies provide a promising method to obtain the high performances for the X-ray detector based on ß-Ga2O3 single crystals.

Analysis and identification of infrared radiation characteristics of different attitude targets.

Today, a large number of targets operate in space, and there are mainly four kinds of attitude targets: triaxial stabilized targets, spin stabilized targets, triaxial stabilized targets on tumbling, and spin stabilized targets on tumbling. It is of great significance to classify and identify these targets. First, the infrared radiation characteristic model of the target is established, taking different attitude targets into account, which, to the best of our knowledge, has seldom been considered. Then, through the simulation of specific example targets, the differences in infrared characteristics of four kinds of attitude targets are analyzed and explained. Finally, according to the orbit distribution and typical geometry structure of space targets, the infrared characteristic data sets of four kinds of attitude targets are simulated, and a classifier is established to classify and recognize these targets. The results show that the infrared characteristics of different attitude targets are obviously different, and the classifier can successfully classify and recognize different attitude targets.

Quantitative proteomics reveals the regulatory networks of circular RNA BTBD7_hsa_circ_0000563 in human coronary artery.

BACKGROUND: BTBD7_hsa_circ_0000563, which is located on chromosome 14, contains conserved binding sites with miR-155/130a and RNA-binding proteins according to bioinformatic prediction. We investigated the association of BTBD7_hsa_circ_0000563 expression in coronary artery segments with atherosclerotic stenosis and identified the proteome-wide BTBD7_hsa_circ_0000563-regulated proteins in human coronary artery. METHODS: The atherosclerotic grade and extent in coronary artery segments were determined by hematoxylin and eosin staining. BTBD7_hsa_circ_0000563 expression in eight coronary artery segments from one patient was quantified by RT-qPCR assay. A proteomic approach was adopted to reveal significant differences in protein expression between among four groups differing in their BTBD7_hsa_circ_0000563 expression levels. RESULTS: The RT-qPCR assay revealed that coronary artery segments with severe atherosclerotic stenosis had significantly low BTBD7_hsa_circ_0000563 levels. The proteomic analysis identified 49 differentially expressed proteins among the segment groups with different BTBD7_hsa_circ_0000563 expression levels, of which 10 were downregulated and 39 were upregulated with increases in the BTBD7_hsa_circ_0000563 level. The 10 downregulated proteins were P61626 (LYSC_HUMAN), P02760 (AMBP_HUMAN), Q02985 (FHR3_HUMAN), P01701 (LV151_HUMAN), P06312(KV401_HUMAN), P01624 (KV315_HUMAN), P13671 (CO6_HUMAN), P01700(LV147_HUMAN), Q9Y287(ITM2B_HUMAN), and A0A075B6I0 (LV861_HUMAN). The top 10 upregulated proteins were Q92552 (RT27_HUMAN), Q9UJY1(HSPB8_HUMAN), Q9Y235(ABEC2_HUMAN), P19022 (CADH2_HUMAN), O43837(IDH3B_HUMAN), Q9H479(FN3K_HUMAN), Q9UM22(EPDR1_HUMAN), P48681(NEST_HUMAN), Q9NRP0(OSTC_HUMAN), and Q15628(TRADD_HUMAN). CONCLUSION: BTBD7_hsa_circ_0000563 is involved in the atherosclerotic changes in human coronary artery segments. Verification, mechanistic, and function studies are needed to confirm whether patients with coronary artery disease would benefit from such personalized medicine in the future.

Directional Control and Enhancement of Light Output of Scintillators by Using Microlens Arrays.

Scintillators play an important role in the field of nuclear radiation detection, such as nuclear medical imaging, dark matter detection, nuclear physics experiments, and national security. However, the light extraction efficiency of a scintillator with a high refractive index is severely restricted because of the total internal reflection. In this paper, microlens arrays have been applied onto the surface of a cerium-doped lutetium-yttrium oxyorthosilicate scintillator to improve the light extraction efficiency and to control the directivity of the light output. Compared to that of a reference sample, a 3.26-fold enhancement with an emission angle of 45° has been obtained by using microlens arrays with optimal parameters. It was also found that the enhancement ratio can be affected by the refractive index of the microlens, the spacing of individual microlens. The control mechanism of microlens arrays is revealed by a combination of simulations and experiments. X-ray imaging characteristics exhibit an improved gray scale amplitude without any loss of the spatial resolution. The present results suggest that the application of microlens arrays to scintillators is beneficial to the field of nuclear radiation detection.

Convenient method for improving the light output of scintillators by using buffer layers coated with photonic crystals.

The low light-extraction efficiency of scintillators is due to total internal reflection and has led to the extensive use of photonic crystals to improve the light output. However, in some applications, photonic crystals cannot be fabricated directly on scintillators. Here, we demonstrate a promising method to improve the light output of scintillators by using a buffer layer coated with photonic crystals and then fixed to the scintillator. Through both numerical simulations and experiments, we investigate how the refractive indexes of the buffer layer and photonic crystal affect the light output from scintillators. The experimental results indicate that the light output of (Lu,Y)2SiO5:Ce scintillators is enhanced 1.9 times by using a sapphire buffer layer coated with an array of polystyrene nanospheres. This method can be used to improve the detection efficiency of radiation-detection systems when photonic crystals cannot be fabricated directly on the scintillator.

Radiomics Based on MRI as a Biomarker to Guide Therapy by Predicting Upgrading of Prostate Cancer From Biopsy to Radical Prostatectomy.

BACKGROUND: Biopsy Gleason score (GS) is crucial for prostate cancer (PCa) treatment decision-making. Upgrading in GS from biopsy to radical prostatectomy (RP) puts a proportion of patients at risk of undertreatment. PURPOSE: To develop and validate a radiomics model based on multiparametric magnetic resonance imaging (mp-MRI) to predict PCa upgrading. STUDY TYPE: Retrospective, radiomics. POPULATION: A total of 166 RP-confirmed PCa patients (training cohort, n = 116; validation cohort, n = 50) were included. FIELD STRENGTH/SEQUENCE: 3.0T/T2 -weighted (T2 W), apparent diffusion coefficient (ADC), and dynamic contrast enhancement (DCE) sequences. ASSESSMENT: PI-RADSv2 score for each tumor was recorded. Radiomic features were extracted from T2 W, ADC, and DCE sequences and Mutual Information Maximization criterion was used to identify the optimal features on each sequence. Multivariate logistic regression analysis was used to develop predictive models and a radiomics nomogram and their performance was evaluated. STATISTICAL TESTS: Student's t or chi-square were used to assess the differences in clinicopathologic data between the training and validation cohorts. Receiver operating characteristic (ROC) curve analysis was performed and the area under the curve (AUC) was calculated. RESULTS: In PI-RADSv2 assessment, 67 lesions scored 5, 70 lesions scored 4, and 29 lesions scored 3. For each sequence, 4404 features were extracted and the top 20 best features were selected. The radiomics model incorporating signatures from the three sequences achieved better performance than any single sequence (AUC: radiomics model 0.868, T2 W 0.700, ADC 0.759, DCE 0.726). The combined mode incorporating radiomics signature, clinical stage, and time from biopsy to RP outperformed the clinical model and radiomics model (AUC: combined model 0.910, clinical model 0.646, radiomics model 0.868). The nomogram showed good performance (AUC 0.910) and calibration (P-values: training cohort 0.624, validation cohort 0.294). DATA CONCLUSION: Radiomics based on mp-MRI has potential to predict upgrading of PCa from biopsy to RP. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 5 J. Magn. Reson. Imaging 2020;52:1239-1248.

Dynamic instability of lithiated phosphorene.

Li-ion batteries are widely used energy storage units. Although phosphorene delivers a high Li capacity, the transition capacity between the intercalation reaction and the conversion reaction is still not clear. We investigate the structural and electronic properties of Li intercalated phosphorene and graphene/phosphorene/graphene sandwiches by first-principles calculations. The competition to obtain charge from Li between C and P reduces charge depletion on the interlayer P-P bonds, improving stability. Importantly, the sandwiches show higher transition capacities than freestanding phosphorene, confirmed by ab initio molecular dynamics simulations. The trilayer structures show better structural reversibility than the monolayers.