Influence of Donor Skeleton on Intramolecular Electron Transfer Amount for Efficient Perovskite Solar Cells.

The passivation of the defects derived from rapid-crystallization with electron-donating molecules is always a prerequisite to obtain desirable perovskite films for efficient and stable solar cells, thus, the in-depth understanding on the correlations between molecular structure and passivation capacity is of great importance for screening passivators. Here, we introduce the double-ended amide molecule into perovskite precursor solution to modulate crystallization process and passivate defects. By regulating the intermediate bridging skeletons with alkyl, alkenyl and benzene groups, the results show the passivation strength highly depends on the spin-state electronic structure that serves as an intrinsic descriptor to determine the intramolecular charge distribution by controlling orbital electron transfer from the donor segment to acceptor segment. Upon careful optimization, the benzene-bridged amide molecule demonstrates superior efficacy on improving perovskite film quality. As a physical proof-of-concept, the carbon-based, all-inorganic CsPbI2Br solar cell delivers a significantly increased efficiency of 15.51 % with a remarkably improved stability. Based on the same principle, a champion efficiency of 24.20 % is further obtained on the inverted (Cs0.05MA0.05FA0.9)Pb(I0.93Br0.07)3 solar cell. These findings provide new fundamental insights into the influence of spin-state modulation on effective perovskite solar cells.

Strain engineering improves the photovoltaic performance of carbon-based hole-transport-material free CsPbIBr2 perovskite solar cells.

Alkylamines with different chain lengths including n-butylamine, n-hexylamine, and n-octylamine, are applied to regulate the CsPbIBr2 perovskite film quality by strain engineering. The status of residual strains is controllably modulated, resulting in improved efficiency and stability of carbon-based hole-transport-material free CsPbIBr2 perovskite solar cells.

Radiomics-based ultrasound models for thyroid nodule differentiation in Hashimoto's thyroiditis.

Background: Previous models for differentiating benign and malignant thyroid nodules(TN) have predominantly focused on the characteristics of the nodules themselves, without considering the specific features of the thyroid gland(TG) in patients with Hashimoto's thyroiditis(HT). In this study, we analyzed the clinical and ultrasound radiomics(USR) features of TN in patients with HT and constructed a model for differentiating benign and malignant nodules specifically in this population. Methods: We retrospectively collected clinical and ultrasound data from 227 patients with TN and concomitant HT(161 for training, 66 for testing). Two experienced sonographers delineated the TG and TN regions, and USR features were extracted using Python. Lasso regression and logistic analysis were employed to select relevant USR features and clinical data to construct the model for differentiating benign and malignant TN. The performance of the model was evaluated using area under the curve(AUC), calibration curves, and decision curve analysis(DCA). Results: A total of 1,162 USR features were extracted from TN and the TG in the 227 patients with HT. Lasso regression identified 14 features, which were used to construct the TN score, TG score, and TN+TG score. Univariate analysis identified six clinical predictors: TI-RADS, echoic type, aspect ratio, boundary, calcification, and thyroid function. Multivariable analysis revealed that incorporating USR scores improved the performance of the model for differentiating benign and malignant TN in patients with HT. Specifically, the TN+TG score resulted in the highest increase in AUC(from 0.83 to 0.94) in the clinical prediction model. Calibration curves and DCA demonstrated higher accuracy and net benefit for the TN+TG+clinical model. Conclusion: USR features of both the TG and TN can be utilized for differentiating benign and malignant TN in patients with HT. These findings highlight the importance of considering the entire TG in the evaluation of TN in HT patients, providing valuable insights for clinical decision-making in this population.

Synergistic Halide- and Ligand-Exchanges of All-Inorganic Perovskite Nanocrystals for Near-Unity and Spectrally Stable Red Emission.

All-inorganic perovskite nanocrystals (NCs) of CsPbX3 (X = Cl, Br, I) are promising for displays due to wide color gamut, narrow emission bandwidth, and high photoluminescence quantum yield (PLQY). However, pure red perovskite NCs prepared by mixing halide ions often result in defects and spectral instabilities. We demonstrate a method to prepare stable pure red emission and high-PLQY-mixed-halide perovskite NCs through simultaneous halide-exchange and ligand-exchange. CsPbBr3 NCs with surface organic ligands are first synthesized using the ligand-assisted reprecipitation (LARP) method, and then ZnI2 is introduced for anion exchange to transform CsPbBr3 to CsPbBrxI3-x NCs. ZnI2 not only provides iodine ions but also acts as an inorganic ligand to passivate surface defects and prevent ion migration, suppressing non-radiative losses and halide segregation. The luminescence properties of CsPbBrxI3-x NCs depend on the ZnI2 content. By regulating the ZnI2 exchange process, red CsPbBrxI3-x NCs with organic/inorganic hybrid ligands achieve near-unity PLQY with a stable emission peak at 640 nm. The CsPbBrxI3-x NCs can be combined with green CsPbBr3 NCs to construct white light-emitting diodes with high-color gamut. Our work presents a facile ion exchange strategy for preparing spectrally stable mixed-halide perovskite NCs with high PLQY, approaching the efficiency limit for display or lighting applications.

Levels, origins and probabilistic health risk appraisal for trace elements in drinking water from Lhasa, Tibet.

Due to the lack of monitoring systems and water purification facilities, residents in western China may face the risk of drinking water pollution. Therefore, 673 samples were collected from Lhasa's agricultural and pastoral areas to reveal the status quo of drinking water. We used inductively coupled plasma-mass spectrometry to determine trace elements concentrations for water quality appraisal, source apportionment, and health risk assessment. The results indicate that concentrations of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Ba, and Pb are below the guidelines, while As concentrations in a few samples exceed the standard. All samples were classified into "excellent water" for drinking purpose based on Entropy-weighted water quality index. Thereafter by principal component analysis, three potential sources of trace elements were extracted, including natural, anthropogenic, and mining activities. It is worth noting that geotherm and mining exploitation does not threaten drinking water safety. Finally, health risks were assessed using Monte Carlo technique. We found that the 95th percentiles of hazard index are 1.80, 0.80, and 0.79 for children, teenagers, and adults, indicating a non-carcinogenic risk for children, but no risks for the latter two age groups. In contrast, the probabilities of unacceptable cautionary risk are 7.15, 2.95 and 0.69% through exposure to Cr, Ni, As, and Cd for adults, children, and teenagers. Sensitivity analyses reveal As concentration and ingestion rate are most influential factors to health risk. Hence, local governments should pay more attention to monitoring and removal of As in the drinking water.

Is the diagnostic model based on convolutional neural network superior to pediatric radiologists in the ultrasonic diagnosis of biliary atresia?

Background: Many screening and diagnostic methods are currently available for biliary atresia (BA), but the early and accurate diagnosis of BA remains a challenge with existing methods. This study aimed to use deep learning algorithms to intelligently analyze the ultrasound image data, build a BA ultrasound intelligent diagnostic model based on the convolutional neural network, and realize an intelligent diagnosis of BA. Methods: A total of 4,887 gallbladder ultrasound images of infants with BA, non-BA hyperbilirubinemia, and healthy infants were collected. Two mask region convolutional neural network (Mask R-CNN) models based on different backbone feature extraction networks were constructed. The diagnostic performance between the two models was compared through good-quality images at the image level and the patient level. The diagnostic performance between the two models was compared through poor-quality images. The diagnostic performance of BA between the model and four pediatric radiologists was compared at the image level and the patient level. Results: The classification performance of BA in model 2 was slightly higher than that in model 1 in the test set, both at the image level and at the patient level, with a significant difference of p = 0.0365 and p = 0.0459, respectively. The classification accuracy of model 2 was slightly higher than that of model 1 in poor-quality images (88.3% vs. 86.4%), and the difference was not statistically significant (p = 0.560). The diagnostic performance of model 2 was similar to that of the two radiology experts at the image level, and the differences were not statistically significant. The diagnostic performance of model 2 in the test set was higher than that of the two radiology experts at the patient level (all p < 0.05). Conclusion: The performance of model 2 based on Mask R-CNN in the diagnosis of BA reached or even exceeded the level of pediatric radiology experts.

Sound touch elastography for assessing cirrhosis preoperatively in infants with biliary atresia: Comparison with serum fibrosis biomarkers.

Introduction: The accurate assessment of the stages of hepatic fibrosis in children with biliary atresia (BA) before performing Kasai portoenterostomy (KPE) is of utmost importance. Some studies demonstrated that ultrasound elastography can be used to assess the stages of hepatic fibrosis by detecting liver stiffness. Therefore, the aim of this work was to explore the usefulness of sound touch elastography (STE) for preoperatively assessing liver cirrhosis in infants with BA. Methods: A total of 189 children from the Hunan Children's Hospital with highly suspected BA were selected for this study, and their preoperative liver STE values and related clinical data were collected. The pathological results of the liver stages were considered as the gold standard. Spearman correlation was used to analyze the correlation between each parameter and the stage of hepatic fibrosis, and the receiver operator characteristic (ROC) curve was used to analyze the diagnostic performance for cirrhosis of each parameter. Results: Among the selected 189 patients with suspected BA, 159 were included in this study and were composed of 3 at hepatic fibrosis stage F1, 45 at stage F2, 41 at stage F3, and 70 at stage F4, while no patients at stage F0 were present. Spearman correlation analysis showed that the liver STE value had the highest correlation with the stage of hepatic fibrosis, with a correlation coefficient of 0.813 (P < 0.001). The liver STE value had the highest diagnostic performance for hepatic cirrhosis compared to other biomarkers of serum fibrosis; the area under the ROC curve was 0.899 when the best cut-off value was 14.57 kPa. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 78.6, 84.3, 79.7, 83.3, and 81.8%, respectively. Conclusion: The liver STE value has a high correlation with the stage of hepatic fibrosis in children with BA. STE has a good diagnostic performance in evaluating cirrhosis before KPE in children with BA.

Efficient Quasi-2D Perovskite Light-Emitting Diodes Enabled by Regulating Phase Distribution with a Fluorinated Organic Cation.

Metal halide perovskites have become a research highlight in the optoelectronic field due to their excellent properties. The perovskite light-emitting diodes (PeLEDs) have achieved great improvement in performance in recent years, and the construction of quasi-2D perovskites by incorporating large-size organic cations is an effective strategy for fabricating efficient PeLEDs. Here, we incorporate the fluorine meta-substituted phenethylammonium bromide (m-FPEABr) into CsPbBr3 to prepare quasi-2D perovskite films for efficient PeLEDs, and study the effect of fluorine substitution on regulating the crystallization kinetics and phase distribution of the quasi-2D perovskites. It is found that m-FPEABr allows the transformation of low-n phases to high-n phases during the annealing process, leading to the suppression of n = 1 phase and increasing higher-n phases with improved crystallinity. The rational phase distribution results in the formation of multiple quantum wells (MQWs) in the m-FPEABr based films. The carrier dynamics study reveals that the resultant MQWs enable rapid energy funneling from low-n phases to emission centers. As a result, the green PeLEDs achieve a peak external quantum efficiency of 16.66% at the luminance of 1279 cd m-2. Our study demonstrates that the fluorinated organic cations would provide a facile and effective approach to developing high-performance PeLEDs.

Ensembled deep learning model outperforms human experts in diagnosing biliary atresia from sonographic gallbladder images.

It is still challenging to make accurate diagnosis of biliary atresia (BA) with sonographic gallbladder images particularly in rural area without relevant expertise. To help diagnose BA based on sonographic gallbladder images, an ensembled deep learning model is developed. The model yields a patient-level sensitivity 93.1% and specificity 93.9% [with areas under the receiver operating characteristic curve of 0.956 (95% confidence interval: 0.928-0.977)] on the multi-center external validation dataset, superior to that of human experts. With the help of the model, the performances of human experts with various levels are improved. Moreover, the diagnosis based on smartphone photos of sonographic gallbladder images through a smartphone app and based on video sequences by the model still yields expert-level performances. The ensembled deep learning model in this study provides a solution to help radiologists improve the diagnosis of BA in various clinical application scenarios, particularly in rural and undeveloped regions with limited expertise.

Preoperative sonographic diagnosis of McSwain type V appendiceal intussusception: A case report (with video).

RATIONALE: Appendiceal intussusception is a rare disease. The definite preoperative diagnosis of appendiceal intussusception is rare and challenging. Here, we present a case of McSwain type V appendiceal intussusception in a 10-year-old boy. To our best knowledge, this is the first case report of a type V appendiceal intussusception that was preoperatively confirmed with sonography. Here, we have described in detail the ultrasound features and differential diagnosis of this rare disease. PATIENT CONCERNS: A 10-year-old boy presented with 3 days of recurrent intermittent mild abdominal pain. The result of ultrasonography suggested an ileocolic intussusception and a therapeutic air-contrast enema was requested to reduce the intussusception but failed at a local hospital. DIAGNOSES: Physical exam revealed mild tenderness in the lower right quadrant of the abdomen. However, ultrasonography showed a target-sign in cross section and a finger-like appearance in the longitudinal view. A diagnosis of McSwain type V appendiceal intussusception was made. INTERVENTIONS: The patient underwent an appendectomy after successful manual reduction on laparotomy. The appendix was successfully resected. OUTCOMES: Intraoperatively, the appendix was completely inverted in the cecum, and the preoperative sonographic findings were confirmed. During follow-up, there were no signs of recurrence. LESSONS: Pre-operatively, on ultrasound a type V appendiceal intussusception is usually misdiagnosed as an ileocolic intussusception. Radiologists must execute caution to avoid over reliance on the sonographic findings of intussusception, especially when there is a mismatch with clinical symptoms. It is especially important to accurately understand the surgical-anatomic configuration of type V appendiceal intussusception that creates a "target-sign" and a "finger-like" layout on ultrasonography.

Does Supersonic Shear Wave Elastography Help Differentiate Biliary Atresia from Other Causes of Cholestatic Hepatitis in Infants Less than 90 Days Old? Compared with Grey-Scale US.

PURPOSE: To investigate the diagnostic performance of shear wave elastography (SWE) for measuring liver stiffness to identify and differentiate biliary atresia (BA) from cholestatic hepatitis in infants younger than 90 days. METHODS: A total of 138 infants younger than 90 days with cholestatic hepatitis were examined by SWE. The infants were subclassified into BA and nonbiliary atresia (non-BA) groups. Receiver operating characteristic (ROC) analysis was used to determine the sensitivity and specificity of hepatic Young's modulus measurements, the ultrasonic findings in the differential diagnosis of suspected BA, and the cut-off value to diagnose BA. RESULTS: In all infants with cholestatic hepatitis, the cut-off value of hepatic Young's modulus to differentiate the BA group from the non-BA group was 12.35 kPa and the area under the ROC curve (AUC) was 0.937, with a sensitivity of 84.3% and a specificity of 89.7%; nevertheless the AUC of the abnormal gallbladder (AbGB) was 0.940, with a sensitivity of 96.1% and a specificity of 92.0%. In the parallel test, triangular cord (TC) sign combined with AbGB had the best diagnostic performance and the AUC was 0.960, with a sensitivity of 100% and a specificity of 92.0%. In the serial test, SWE combined with AbGB achieved the best diagnostic performance; the AUC was 0.902, the sensitivity and specificity were 80.4% and 100%, respectively. CONCLUSIONS: SWE could not only help differentiate BA from cholestatic hepatic diseases but also increase the diagnostic specificity when combined with grey-scale ultrasound in the serial test.

Succession of bacterial microbiota in tilapia fillets at 4 °C and in situ investigation of spoilers.

The succession of bacterial microbiota in tilapia fillets during cold storage at 4 °C was investigated employing PCR-DGGE method. Results showed that Pseudomonas was the most dominant genus during entire storage period. Shewanella and Psychrobacter were also always present, but became dominant only after 3 days of storage. Acinetobacter, Brevibacterium, Flavobacterium, Dietzia and Janthinobacterium were always the minor genera, among which Acinetobacter and Brevibacterium disappeared 6 days later, and Dietzia and Janthinobacterium only appeared at the end of storage. Further, the potential spoiler(s) of tilapia fillets at 4 °C were investigated in situ. The spoilage ability of a specific group of bacteria was evaluated as follows: Certain preservatives were selectively added to fillets to inhibit a specific group of bacteria, and then the changes in spoilage degree of fillets were determined. In this way the spoilage ability of the inhibited bacteria was evaluated. Our experiments showed that protamine strongly inhibited Pseudomonas but rarely inhibited Psychrobacter, Acinetobacter and Brevibacterium, but garlic juice, on the contrary, strongly inhibited the latter three but rarely inhibited the former. The mixed preservative, which consisted of protamine and garlic juice, didn't play better than protamine alone in preventing the spoilage of fillets. This indicated that Psychrobacter, Acinetobacter and Brevibacterium contribute little to the spoilage of tilapia fillets.

[Effect of polyethylene oxide on renal hemodynamics in rabbits with endotoxin shock].

OBJECTIVE: To investigate the effect of polyethylene oxide (PEO) on renal blood flow and its renoprotective effect in rabbits with endotoxin sepsis. METHODS: Twenty normal New Zealand white rabbits were randomly divided into normal saline (NS) group and PEO group (n=10), and endotoxin shock was induced by an intravenous injection of 0.6 mg/kg lipopolysaccharide. Resuscitation was performed when the blood pressure of the rabbits showed a 30% decline, using NS (in NS group) or the mixture of equal volumes of NS and 20 ng/g PEO (in PEO group) perfused at the rate of 5 ml/kg per hour. Before and during shock and at 1 h after resuscitation, the renal hemodynamics was monitored by ultrasound and the venous blood was extracted to examine the renal functions. The heart rate and arterial blood pressure were monitored throughout the experiment. RESULTS: The rabbits in both groups showed a significantly lower renal artery blood flow velocity during the shock (P<0.05) with significantly increased pulsatility index (PI) and resistance index (RI) compared with those before the shock. One hour after resuscitation, the blood flow velocity in the renal arteries at all levels and the tertiary veins were reduced in NS group without obvious reduction of the PI and RI; in PEO group, the blood flow velocities in the renal arteries increased significantly compared to those before shock (P<0.05), and the PI and RI of the tertiary arteries were significantly lower than those in NS group (P<0.05). In both groups, BUN and Cr increased during endotoxin shock stage, and 1 h after resuscitation, PEO group showed significantly lower BUN and Cr levels than NS group (P<0.05). CONCLUSION: A small dose of PEO can significantly promote renal perfusion in rabbits with septic shock, thus offering renoprotective effect against early damage in septicopyemia and septic shock.

[Evaluation of intraventricular dyssynchrony by quantitative tissue velocity imaging in rats of post-infarction heart failure].

OBJECTIVE: To evaluate intraventricular systolic dyssynchrony in rats with post-infarction heart failure by quantitative tissue velocity imaging combining synchronous electrocardiograph. METHODS: A total of 60 male SD rats were randomly assigned to 3 groups: a 4 week post-operative group and an 8 week post-operation group (each n=25, with anterior descending branch of the left coronary artery ligated), and a sham operation group (n=10, with thoracotomy and open pericardium, but no ligation of the artery). The time to peak systolic velocity of regional myocardial in the rats was measured and the index of the left intraventricular dyssynchrony was calculated. RESULTS: All indexes of the heart function became lower as the heart failure worsened except the left ventricle index in the post-operative groups. All indexes of the dyssynchrony got longer in the post-operative groups (P<0.05), while the changes in the sham operation group were not significantly different (P>0.05). CONCLUSION: Quantitative tissue velocity imaging combining synchronous electrocardiograph can analyse the intraventricular systolic dyssynchrony accurately.

[Evaluation of the myocardial systolic function and ventricular remodeling of rats with experimental myocardial infarction by strain/strain rate imaging and MMP-9].

OBJECTIVE: To evaluate the myocardial systolic function and ventricular remodeling in heart failure rat induced by myocardial infarction (MI) with S/SRI and MMP-9. METHODS: A total of 70 male SD rats were randomly assigned to 4 groups: 4 weeks and 8 weeks MI (anterior descending branch of left coronary artery were ligated), sham operation (thoracotomy without ligation of coronary artery) and non-operated control group. The regional myocardial systolic function of rats was quantified with S/SRI. The myocardial MMP-9 expression was detected by Western blot. RESULTS: In the 4 weeks MI group, all segment's Ssys, SRsys, the strain of end-systole were reduced while PSI was increased compared to sham and non-operated group with the exception of the inferior wall. These changes were more significant in 8 weeks MI group compared to the 4 weeks MI group. In the 4 weeks MI group, the expression of MMP-9 was significantly upregulated than the sham operation group and this upregulation was more significant at 8 weeks post MI. CONCLUSIONS: S/SRI can quantitative evaluate the regional systolic function of heart failure rat induced by myocardial infarction. Progressive upregulation of myocardial MMP-9 expression paralleled the deterioration of regional systolic function in this heart failure rat model.

[Evaluation of myocardial systolic function of heart failure induced by myocardial infarction in rats with strain and strain rate imagine].

OBJECTIVE: To quantitatively detect variation in regional myocardial systolic function in heart failure rat model induced by myocardial infarction by strain and strain rate imaging. METHODS: Seventy 2-month-old adult male SD rats were randomly assigned to 4 groups: a 4-week and a 8-week group after the operation (each n = 25) had thoracotomy, the pericardium opened and the anterior descending branch of left coronary artery ligated; a sham operation group (n = 10) had thoracotomy and the arcula cordis opened, but did not ligate the artery; a control group (n = 10) had no treatment. The changes of general state of health of the rats were observed and recorded every day. To assess the change of heart function, echocardiography was used at the end of the 4th week and 8th week after the surgery. To evaluate the change of heart function in heart failure rats, we quantitatively analyzed the regional myocardial systolic function in all rats by strain and strain rate imaging and myocardium to detect the level of MMP-9 at the end of the 4th week and 8th week. The repeatability and discrepancies of the results were all analyzed. RESULTS: Obviously objective signs of heart failure manifested themselves in the survived mice 10 to 14 days after the surgery. Compared with the control group and the sham operation group, the fraction shortening (FS) and ejection fraction (EF) of the 4-week group after the operation were lower (P < 0.05), the left ventricle index (LV index) of the 8-week group after the operation was higher, left ventricle posterior wall index (LVPW index), interventricular septum index (IVS index), FS, and EF of the 8-week group after the operation were lower (P < 0.05), EF and FS of the 8-week group after the operation were lower than those of the 4-week group. Except the mid-inferior wall and base-inferior wall, the systolic peak strain, systolic peak strain rate, the strain of end-systole in all segments of the operation group were lower than those of the other 2 groups (P < 0.05). The post-systolic strain index of the operation group was higher than that of the other 2 groups (P < 0.05). CONCLUSION: Strain and strain rate imaging of echocardiography can quantitatively evaluate the changing of regional myocardial systolic function in the heart failure rat model induced by myocardial infarction, with good repeatability.