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1.
J Colloid Interface Sci ; 607(Pt 2): 1796-1804, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34600343

RESUMO

Mixed-halide blue perovskites CsPb(Br/Cl)3 are considered promising candidates for developing efficient deep-blue perovskite light-emitting diodes (PeLEDs), but their low photoluminescence quantum yield (PLQY), environmental instability, and poor device performance gravely inhibit their future development. Here, we employ a heteroatomic Cu2+ doping strategy combined with post-treatment Br- anion exchange to prepare high-performance deep-blue perovskites CsPb(Br/Cl)3. The Cu2+ doping strategy significantly decreases the intrinsic chlorine defects, ensuring that the inferior CsPbCl3 quantum dots are transformed into two-dimensional nanosheets with enhanced violet photoluminescence and increased exciton binding energy. Further, with the post-treatment Br- anion exchange, the as-prepared CsPb(Br/Cl)3 nanosheets with more radiation recombination and less ion migration present an enhanced PLQY of 94% and better humidity stability of 30 days. Based on the optimized CsPb(Br/Cl)3, we fabricated deep-blue PeLEDs with luminescence emission at 462 nm, a maximum luminance of 761 cd m-2, and a current density of 205 mA cm-2. This work puts forward a feasible synthesis strategy to prepare efficient and stable mixed-halide blue perovskite CsPb(Br/Cl)3 and related blue PeLEDs, which may promote the further application of mixed-halide perovskites in the blue light range.

3.
Artigo em Inglês | MEDLINE | ID: mdl-34812603

RESUMO

Precisely tuning emission spectra through the component control of mixed halides has been proved to be an efficient method for procuring deep-blue perovskite LEDs (PeLEDs). However, the inferior color instability and lifetime attenuation, originated from vacancy- and trap-mediated mechanisms under an external field, remain an uninterruptedly formidable challenge for the commercial development of PeLEDs. Here, an ultrafast thermodynamics-induced injection enhancement strategy was employed to promote efficient carrier recombination within perovskite quantum dots (QDs), accompanied by less inefficient charge accumulation and trap generation, enabling deep-blue PeLEDs with improved thermal and spectral stability. The resultant PeLEDs feature an external quantum efficiency (EQE) of 3.66%, a max luminance of 2100 cd/m2 at the electroluminescence (EL) of 460 nm, and a halftime of 288 s. This work provides a general platform for promoting the EL performances and a deep insight into unraveling the degradation mechanism of blue PeLEDs.

4.
BMC Med Inform Decis Mak ; 21(Suppl 9): 317, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34789262

RESUMO

BACKGROUND: A lot of medical mentions can be extracted from a huge amount of medical texts. In order to make use of these medical mentions, a prerequisite step is to link those medical mentions to a medical domain knowledge base (KB). This linkage of mention to a well-defined, unambiguous KB is a necessary part of the downstream application such as disease diagnosis and prescription of drugs. Such demand becomes more urgent in colloquial and informal situations like online medical consultation, where the medical language is more casual and vaguer. In this article, we propose an unsupervised method to link the Chinese medical symptom mentions to the ICD10 classification in a colloquial background. METHODS: We propose an unsupervised entity linking model using multi-instance learning (MIL). Our approach builds on a basic unsupervised entity linking method (named BEL), which is an embedding similarity-based EL model in this paper, and uses MIL training paradigm to boost the performance of BEL. First, we construct a dataset from an unlabeled large-scale Chinese medical consultation corpus with the help of BEL. Subsequently, we use a variety of encoders to obtain the representations of mention-context and the ICD10 entities. Then the representations are fed into a ranking network to score candidate entities. RESULTS: We evaluate the proposed model on the test dataset annotated by professional doctors. The evaluation results show that our method achieves 60.34% accuracy, exceeding the fundamental BEL by 1.72%. CONCLUSIONS: We propose an unsupervised entity linking method to the entity linking in the medical domain, using MIL training manner. We annotate a test set for evaluation. The experimental results show that our model behaves better than the fundamental model BEL, and provides an insight for future research.


Assuntos
Mineração de Dados , Processamento de Linguagem Natural , Humanos , Bases de Conhecimento , Idioma
5.
Chemistry ; 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34747069

RESUMO

Recently, perovskites have attracted intense attention due to their high potential in optoelectronic applications. Employing perovskites as the emissive materials of light-emitting electrochemical cells (LECs) shows the advantages of simple fabrication process, low-voltage operation, and compatibility with inert electrodes, along with saturated electroluminescence (EL) emission. Unlike in previously reported perovskite LECs, in which salts are incorporated in the emissive layer, the ion-transport layer was separated from the emissive layer in this work. The layer of ionic transition metal complex (iTMC) not only provides mobile ions but also serves as an electron-injection/transport layer. Orthogonal solvents are used in spin coating to prevent the intermixing of stacked perovskite and iTMC layers. The blue iTMC with high ionization potential is effective in blocking holes from the emissive layer and thus ensures EL color saturation. In addition, the carrier balance of the perovskite/iTMC LECs can be optimized by adjusting the iTMC layer thickness. The optimized external quantum efficiency of the CsPbBr3 /iTMC LEC reaches 6.8 %, which is among the highest reported values for perovskite LECs. This work successfully demonstrates that, compared with mixing all components in a single emissive layer, separating the layer of ion transport, electron injection and transport from the perovskite emissive layer is more effective in adjusting device carrier balance. As such, solution-processable perovskite/iTMC LECs open up a new way to realize efficient perovskite LECs.

6.
Biomed Res Int ; 2021: 6762724, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34722768

RESUMO

Introduction: We present a mathematical method to adjust the leaf end position for dose calculation correction in the carbon ion radiation therapy treatment planning system. Methods and Materials: A straggling range algorism of 400 MeV/n carbon ion beam in nine different multileaf collimator (MLC) materials was conducted to calculate the dose 50% point to derive the offset corrections in the carbon ion treatment planning system (ciPlan). The visualized light field edge position in the treatment planning system is denoted as X tang.p, and MLC position (X mlc.p) is defined as the source to leaf end midpoint projection on axis for monitor unit calculation. The virtual source position of energy at 400 MeV/n and straggling range in MLC at different field sizes were used to calculate the dose 50% position on axis. On-axis MLC offset (correction) could then be obtained from the position corresponding to 50% of the central axis dose minus the X mlc.p. Results: The exact MLC position in the carbon ion treatment planning system can be used as an offset to do the correction. The offset correction of pure tungsten is the smallest among the others due to its shortest straggling range of carbon ion beam in MLC. The positions of 50% dose of all MLC materials are always located in between X tang.p and X mlc.p under the largest field of 12 cm by 12 cm. Conclusions: MLC offset should be adjusted carefully at different field sizes in the treatment planning systems especially of its small penumbra characteristic in the carbon ion beam. It is necessary to find out the dose 50% position for adjusting MLC leaf edge on-axis location in the treatment planning system to reduce dose calculation error.

7.
Biomed Res Int ; 2021: 8808537, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34722774

RESUMO

Purpose: An experimental and mathematical study for determining the effective point of measurement (P eff) for a Farmer-type cylindrical chamber in a carbon ion passive scatter beam is presented. Methods: The ionization depth curves measured by the Bragg peak chamber were plotted according to the position of the inner surface of the entrance window, while the Farmer chamber was plotted at the tip of the cylindrical geometric center. The ionization depth curves measured by a cylindrical chamber in the 3D water phantom were then compared with a high-precision parallel-plate PTW Bragg peak chamber for inspecting the upstream shift correction of the cylindrical chamber in the carbon ion beam. A component of the vertical and horizontal integration method and the barrier model, cosφ = 1 - [2αR L /(1 + α - R L )], for analyzing the shift of effective point of measurement in different carbon ion energies and various field sizes, were studied. Results: The shift between the maximum peak of the Bragg peak chamber and the Farmer chamber in a field size of 10 cm × 10 cm with an energy of 330 MeV/u of carbon ion is 2.3 mm. This upstream shift corresponds to (0.744 ± 0.07)r, where r is the Farmer chamber inner radius of 3.05 mm. Carbon ion energy from 120 MeV/u to 400 MeV/u with different field sizes show different shifts of effective point of measurement in a range of (0.649 ± 0.02)r to (0.843 ± 0.06)r of 3 cm × 3 cm at an energy of 400 MeV/u and 10 cm × 10 cm at an energy of 120 MeV/u, respectively. The vertical and horizontal scatter analysis by the barrier model can precisely describe the shift of the effective point of measurement at different carbon ion energies with various field sizes. Conclusions: We conclude that the Farmer chamber can be used for a patient-specific dose verification check in carbon ion beam treatment if P eff is well calibrated.

8.
Nat Commun ; 12(1): 6538, 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34764303

RESUMO

The Mizoroki-Heck reaction and its reductive analogue are staples of organic synthesis, but the ensuing products often lack a chemical handle for further transformation. Here we report an atom-economical cross-coupling of halopyridines and unactivated alkenes under photoredox catalysis to afford a series of alkene halopyridylation products. This protocol with mild and redox neutral conditions contributes broad substrate scope. As a complement to conventional Heck-type reaction, this radical process avoids the involvement of ß-H elimination and thus useful pyridyl and halide groups could be simultaneously and regioselectively incorporated onto alkenes. The success depends on TFA-promoted domino photocatalytic oxidative quenching activation and radical-polar crossover pathway. Plausible mechanism is proposed based on mechanistic investigations. Moreover, the reserved C - X bonds of these products are beneficial for performing further synthetic elaborations.

9.
Antioxidants (Basel) ; 10(11)2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34829537

RESUMO

To identify the core structure of 2-aminoethoxydiphenyl borate (2-APB) responsible for the anti-oxidative and protective effect on the ischemia/reperfusion (I/R)-induced heart injury, various 2-APB analogues were analyzed, and several antioxidant assays were performed. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Myocardial infarct size was quantified using triphenyl tetrazolium chloride (TTC) staining. The levels of tumor necrosis factor-alpha (TNF-α) and cleaved-caspase-3 protein were evaluated as an indicator for the anti-inflammatory and anti-apoptotic effect, respectively. Our data show that 2-APB, diphenylborinic anhydride (DPBA) and 3-(diphenylphosphino)-1-propylamine (DP3A) all exerted the anti-oxidative activity, but only 2-APB and DPBA can scavenge H2O2. 2-APB and DPBA can potently inhibit hydrogen peroxide (H2O2)- and hypoxanthine/xanthine oxidase (HX/XOD)-induced increases in intracellular H2O2 and H9c2 cell death. 2-APB and DPBA were able to decrease the I/R-induced adult rat cardiomyocytes death, myocardial infarct size, and the levels of malondialdehyde (MDA) and creatine kinase-MB (CK-MB). Our results suggest that the two benzene rings with a boron atom comprise the core structure of 2-APB responsible for the anti-oxidative effect mediated through the reaction with H2O2 and generation of phenolic compounds, which in turn reduced the I/R-induced oxidative stress and injury in the rat heart.

10.
Int J Mol Sci ; 22(22)2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34830140

RESUMO

The smut fungus Ustilago esculenta infects Zizania latifolia and induces stem expansion to form a unique vegetable named Jiaobai. Although previous studies have demonstrated that hormonal control is essential for triggering stem swelling, the role of hormones synthesized by Z. latifolia and U. esculenta and the underlying molecular mechanism are not yet clear. To study the mechanism that triggers swollen stem formation, we analyzed the gene expression pattern of both interacting organisms during the initial trigger of culm gall formation, at which time the infective hyphae also propagated extensively and penetrated host stem cells. Transcriptional analysis indicated that abundant genes involving fungal pathogenicity and plant resistance were reprogrammed to maintain the subtle balance between the parasite and host. In addition, the expression of genes involved in auxin biosynthesis of U. esculenta obviously decreased during stem swelling, while a large number of genes related to the synthesis, metabolism and signal transduction of hormones of the host plant were stimulated and showed specific expression patterns, particularly, the expression of ZlYUCCA9 (a flavin monooxygenase, the key enzyme in indole-3-acetic acid (IAA) biosynthesis pathway) increased significantly. Simultaneously, the content of IAA increased significantly, while the contents of cytokinin and gibberellin showed the opposite trend. We speculated that auxin produced by the host plant, rather than the fungus, triggers stem swelling. Furthermore, from the differently expressed genes, two candidate Cys2-His2 (C2H2) zinc finger proteins, GME3058_g and GME5963_g, were identified from U. esculenta, which may conduct fungus growth and infection at the initial stage of stem-gall formation.

11.
Acad Radiol ; 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34654622

RESUMO

RATIONALE AND OBJECTIVES: To evaluate the material decomposition (MD) techniques in rapid kVp switching dual-energy CT (rsDECT) for quantifying liver fat content in rats with nonalcoholic fatty liver. MATERIALS AND METHODS: Fifty male Sprague-Dawley (SD) rats were divided into study group (n=37) and control group (n = 13) and underwent rsDECT examination at different intervals. All the data analysis was performed using AW4.7 workstation. The fat contents under the traditional fat(water), fat(blood), and fat(muscle) material decomposition (MD) images and the fat volume fraction (FVF) from the liver fat maps generated using multi-material decomposition (MMD) technique were measured. The pathological grades (grade 0, 1, 2 and 3) of fatty liver were determined after euthanasia. The measurement differences among different grades and the correlation of measurements with different grades was analyzed using ANOVA and Spearman correlation, respectively. A receiver operating characteristics (ROC) curve was used to analyze the diagnostic efficacies of fat contents and FVF. RESULTS: There were statistically significant differences in FVF and fat contents under fat(water), fat(blood), fat(muscle) based MD images among different grades. These values correlated well with the pathological grades (R-value: 0.90, 0.75, 0.79, 0.80, all p <0.001), with FVF having the highest correlation. The area-under-the-curve in ROC of using FVF was the highest, with the cut-off value of 0.92 for sensitivity of 89.2% and specificity of 100%. CONCLUSION: The rsDECT MD techniques could quantitatively evaluate the fat content of fatty liver in rat, with the FVF from MMD having the highest correlation with pathological grades.

12.
World J Clin Cases ; 9(26): 7653-7670, 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34621817

RESUMO

BACKGROUND: Ulcerative colitis (UC) is a refractory intestinal disease with alternating onset and remission and a long disease course, which seriously affects the health and quality of life of patients. The goal of treatment is to control clinical symptoms, induce and maintain remission, promote mucosal healing, and reduce recurrence. Clinical trials have shown unsatisfactory clinical response rates. As a supplementary alternative medicine, traditional Chinese medicine has a rich history and has shown good results in the treatment of UC. Because of the quality of herbal medicine and other factors, the curative effect of traditional Chinese medicine is not stable enough. The mechanism underlying the effect of Jianpi Qingchang Huashi Recipe (JPQCHSR) on inducing UC mucosal healing is not clear. AIM: To investigate the potential mechanism of JPQCHSR for the treatment of UC based on network pharmacology and molecular docking. METHODS: Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform was used to extract the active components and action targets of JPQCHSR, and the target names were standardized and corrected through UniProt database. The related targets of UC were obtained through GeneCards database, and the intersection targets of drugs and diseases were screened by jvenn online analysis tool. The visual regulatory network of "Traditional Chinese medicine-active components-target-disease" was constructed using Cytoscape software, the protein interaction network was constructed using STRING database, and enrichment analysis of gene ontology and Kyoto Encyclopedia of Genes and Genomes pathways was conducted through R software. At last, the active components were docked with the core target through SYBYL-X 2.1.1 software. RESULTS: Through database analysis, a total of 181 active components, 302 targets and 205 therapeutic targets were obtained for JPQCHSR. The key compounds include quercetin, luteolin, kaempferol, etc. The core targets involved STAT3, AKT1, TP53, MAPK1, MAPK3, JUN, TNF, etc. A total of 2861 items were obtained by GO enrichment analysis, and 171 items were obtained by KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis. The results of molecular docking showed that the key active components in JPQCHSR had certain affinity with the core target. CONCLUSION: The treatment of UC with JPQCHSR is a complex process of multi-component, multi-target and multi-pathway regulation. The mechanism of this Recipe in the treatment of UC can be predicted through network pharmacology and molecular docking, so as to provide theoretical reference for it to better play its therapeutic role.

13.
Nutr Metab (Lond) ; 18(1): 88, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34620199

RESUMO

BACKGROUND: Time-restricted feeding is an emerging dietary intervention that is becoming increasingly popular. There are, however, no randomised clinical trials of time-restricted feeding in overweight patients with type 2 diabetes. Here, we explored the effects of time-restricted feeding on glycaemic regulation and weight changes in overweight patients with type 2 diabetes over 12 weeks. METHODS: Overweight adults with type 2 diabetes (n = 120) were randomised 1:1 to two diet groups: time-restricted feeding (n = 60) or control (n = 60). Sixty patients participated in a 10-h restricted feeding treatment program (ad libitum feeding from 8:00 to 18:00 h; fasting between 18:00 and 8:00 h) for 12 weeks. RESULTS: Haemoglobin A1c and body weight decreased in the time-restricted feeding group (- 1.54% ± 0.19 and - 2.98 ± 0.43 kg, respectively) relative to the control group over 12 weeks (p < 0.001). Homeostatic model assessment of ß-cell function and insulin resistance changed in the time-restricted feeding group (0.73 ± 0.21, p = 0.005; - 0.51 ± 0.08, p = 0.02, respectively) compared with the control group. The medication effect score, SF-12 score, and the levels of triglycerides, total cholesterol and low-density lipoprotein cholesterol were improved in the time-restricted feeding group (- 0.66 ± 0.17, p = 0.006; 5.92 ± 1.38, p < 0.001; - 0.23 ± 0.08 mmol/L, p = 0.03; - 0.32 ± 0.07 mmol/L, p = 0.01; - 0.42 ± 0.13 mmol/L, p = 0.02, respectively) relative to the control group. High-density lipoprotein cholesterol was not significantly different between the two groups. CONCLUSION: These results suggest that 10-h restricted feeding improves blood glucose and insulin sensitivity, results in weight loss, reduces the necessary dosage of hypoglycaemic drugs and enhances quality of life. It can also offer cardiovascular benefits by reducing atherosclerotic lipid levels. TRIAL REGISTRATION: This study was registered with the Chinese Clinical Trial Registry (ChiCTR-IPR-15006371).

14.
Nanoscale ; 13(43): 18010-18031, 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34718363

RESUMO

All inorganic perovskites CsPbX3 (X = Cl, Br, I), rising stars of optical materials, have shown promising application prospects in optoelectronic and photovoltaic fields. However, some open issues still exist in these perovskites, like poor long-term stability, inevitable intrinsic defects and much nonradiative recombination, which greatly weakens their optical capability and seriously hinders their further development. The metal doping strategy, through the partial substitution of foreign ions for native ions, has gradually become an effective method for significantly enhancing the comprehensive properties of CsPbX3. Whereas some previous studies have reported the impressive properties of metal-doped CsPbX3, there is still a lack of a comprehensive review on the influences of metal doping on CsPbX3. In this review, we aim to provide a systematic review of the latest achievements in metal-doped CsPbX3, which focuses on their synthetic methods and the positive effects of metal doping on structure, optical properties, morphology control, carrier behavior and related optoelectronic and photovoltaic devices. Finally, we put forward a few opportunities and challenges about the further investigation of metal-doped perovskites, which may help researchers explore new research directions.

15.
ACS Appl Mater Interfaces ; 13(41): 49390-49401, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34609832

RESUMO

Li-rich Mn-based-layered oxides are considered to be the most felicitous cathode material candidates for commercial application of lithium-ion batteries on account of high energy density. Nevertheless, defects containing an unsatisfactory initial Coulombic efficiency and rapid voltage decay seriously impede their practical utilization. Herein, a coating layer with three distinct crystalline states are employed as a coating layer to modify Li[Li0.2Mn0.54Ni0.13Co0.13]O2, respectively, and the effects of coating layers with distinct crystalline states on the crystal structure, diffusion kinetics, and cell performance of host materials are further explored. A coating layer with high crystallinity enables mitigatory voltage decay and better cyclic stability of materials, while a coating layer with planar defects facilitates Li+ transfer and enhances the rate performance of materials. Consequently, optimizing the crystalline state of coating substances is critical for preferable surface modification.

16.
Biomed Res Int ; 2021: 3397350, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34660785

RESUMO

Introduction: This study presents an empirical method to model the curve of electron beam percent depth dose (PDD) by using the primary-tail function in electron beam radiation therapy. The modeling parameters N and n can be used to predict the minimal side length when the field size is reduced below that required for lateral scatter equilibrium (LSE) in electron radiation therapy. Methods and Materials: The electrons' PDD curves were modeled by the primary-tail function in this study. The primary function included the exponential function and the main parameters of N and µ, while the tail function was composed of a sigmoid function with the main parameter of n. The PDD of five electron energies was modeled by the primary and tail function by adjusting the parameters of N, µ, and n. The R 50 and R p can be derived from the modeled straight line of 80% to 20% region of PDD. The same electron energy with different cone sizes was also modeled by the primary-tail function. The stopping power of different electron energies in different depths can also be derived from the parameters N, µ, and n. Results: The main parameters N and n increase but µ decreases in the primary-tail function for characterizing the electron beam PDD when the electron energy increased. The relationship of parameter n, N, and ln(-µ) with electron energy are n = 31.667E 0 - 88, N = 0.9975E 0 - 2.8535, and ln(-µ) = -0.1355E 0 - 6.0986, respectively. Percent depth dose was derived from the percent reading curve by multiplying the stopping power relevant to the depth in water at a certain electron energy. The stopping power of different electron energies can be derived from n and N with the following equation: stopping power = (-0.042ln(N E 0 ) + 1.072)e (-nE0 · 5 · 10-5 + 0.0381)·x , where x is the depth in water. The lateral scatter equivalence (LSE) of the clinical electron beam can be described by the parameters E 0, n, and N in the equation of Seq = (n E 0 - N E 0 )0.288/(E 0/n E 0 )0.0195. The LSE was compared with the root mean square scatter angular distribution method and shows the agreement of depth dose distributions within ±2%. Conclusions: The PDD of the electron beam at different energies and cone sizes can be modeled with an empirical model to deal with what is the minimal field size without changing the percent depth dose when approximate LSE is given in centimeters of water.

17.
Comput Math Methods Med ; 2021: 5812499, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34527076

RESUMO

Artificial intelligence (AI) is making computer systems capable of executing human brain tasks in many fields in all aspects of daily life. The enhancement in information and communications technology (ICT) has indisputably improved the quality of people's lives around the globe. Especially, ICT has led to a very needy and tremendous improvement in the health sector which is commonly known as electronic health (eHealth) and medical health (mHealth). Deep machine learning and AI approaches are commonly presented in many applications using big data, which consists of all relevant data about the medical health and diseases which a model can access at the time of execution or diagnosis of diseases. For example, cardiovascular imaging has now accurate imaging combined with big data from the eHealth record and pathology to better characterize the disease and personalized therapy. In clinical work and imaging, cancer care is getting improved by knowing the tumor biology and helping in the implementation of precision medicine. The Markov model is used to extract new approaches for leveraging cancer. In this paper, we have reviewed existing research relevant to eHealth and mHealth where various models are discussed which uses big data for the diagnosis and healthcare system. This paper summarizes the recent promising applications of AI and big data in medical health and electronic health, which have potentially added value to diagnosis and patient care.

18.
iScience ; 24(9): 102969, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34466792

RESUMO

Ritter reaction has been recognized as an elegant strategy to construct the C-N bond. Its key feature is forming the carbocation for nucleophilic attack by nitriles. Herein, we report a complementary visible-light-induced three-component Ritter reaction of alkenes, nitriles, and α-bromo nitriles/esters, thereby providing mild and rapid access to various γ-amino nitriles/acids. Mechanistic studies indicated that traceless fluoride relay, transforming KF into imidoyl fluoride intermediate, is critical for the efficient reaction switch from atom transfer radical addition (ATRA) to the Ritter reaction. This approach to amino-alkylation of alkenes is chemoselective and operationally simple.

19.
Materials (Basel) ; 14(17)2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34500909

RESUMO

This study attempts to investigate the warpage behavior of a flip chip package-on-package (FCPoP) assembly during fabrication process. A process simulation framework that integrates thermal and mechanical finite element analysis (FEA), effective modeling and ANSYS element death-birth technique is introduced for effectively predicting the process-induced warpage. The mechanical FEA takes into account the viscoelastic behavior and cure shrinkage of the epoxy molding compound. In order to enhance the computational and modeling efficiency and retain the prediction accuracy at the same time, this study proposes a novel effective approach that combines the trace mapping method, rule of mixture and FEA to estimate the effective orthotropic elastic properties of the coreless substrate and core interposer. The study begins with experimental measurement of the temperature-dependent elastic and viscoelastic properties of the components in the assembly, followed by the prediction of the effective elastic properties of the orthotropic interposer and substrate. The predicted effective results are compared against the results of the ROM/analytical estimate and the FEA-based effective approach. Moreover, the warpages obtained from the proposed process simulation framework are validated by the in-line measurement data, and good agreement is presented. Finally, key factors that may influence process-induced warpage are examined via parametric analysis.

20.
BMC Cancer ; 21(1): 986, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34479488

RESUMO

BACKGROUND: Prosthesis-related complications, after knee reconstruction with endoprosthesis during operation for tumors around the knee, remain an unresolved problem which necessitate a revision or even an amputational surgery. The purpose of the current study was to identify significant risk factors associated with implant failure, and establish a novel model to predict survival of the prosthesis in patients operated with endoprostheses for tumor around knee. METHODS: We retrospectively reviewed the clinical database of our institution for patients who underwent knee reconstruction due to tumors. A total of 203 patients were included, including 123 males (60.6%) and 80 (39.4%) females, ranging in age from 14 to 77 years (mean: 34.3 ± 17.3 years). The cohort was randomly divided into training (n = 156) and validation (n = 47) samples. Univariable COX analysis was used for initially identifying potential independent predictors of prosthesis survival with the training group (p < 0.150). Multivariate COX proportional hazard model was selected to identify final significant prognostic factors. Using these significant predictors, a graphic nomogram, and an online dynamic nomogram were generated for predicting the prosthetic survival. C-index and calibration curve were used for evaluate the discrimination ability and accuracy of the novel model, both in the training and validation groups. RESULTS: The 1-, 5-, and 10-year prosthetic survival rates were 94.0, 90.8, and 83.0% in training sample, and 96.7, 85.8, and 76.9% in validation sample, respectively. Anatomic sites, length of resection and length of prosthetic stem were independently associated with the prosthetic failure according to multivariate COX regression model (p<0.05). Using these three significant predictors, a graphical nomogram and an online dynamic nomogram model were generated. The C-indexes in training and validation groups were 0.717 and 0.726 respectively, demonstrating favourable discrimination ability of the novel model. And the calibration curve at each time point showed favorable consistency between the predicted and actual survival rates in training and validation samples. CONCLUSIONS: The length of resection, anatomical location of tumor, and length of prosthetic stem were significantly associated with prosthetic survival in patients operated for tumor around knee. A user-friendly novel online model model, with favorable discrimination ability and accuracy, was generated to help surgeons predict the survival of the prosthesis.


Assuntos
Prótese do Joelho/estatística & dados numéricos , Neoplasias/cirurgia , Nomogramas , Próteses e Implantes/estatística & dados numéricos , Falha de Prótese/tendências , Procedimentos Cirúrgicos Reconstrutivos/métodos , Adolescente , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/patologia , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
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