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Trichomes, the hair-like structures located on aerial parts of most vascular plants, are associated with a wide array of biological processes and affect the economic value of certain species. The processes involved in unicellular trichome formation have been well-studied in Arabidopsis (Arabidopsis thaliana). However, our understanding of the morphological changes and the underlying molecular processes involved in multicellular trichome development is limited. Here, we studied the dynamic developmental processes involved in glandular and nonglandular multicellular trichome formation in cucumber (Cucumis sativus L.) and divided these processes into five sequential stages. To gain insights into the underlying mechanisms of multicellular trichome formation, we performed a time-course transcriptome analysis using RNA-sequencing analysis. A total of 711 multicellular trichome-related genes were screened and a model for multicellular trichome formation was developed. The transcriptome and co-expression datasets were validated by reverse transcription-quantitative PCR and in situ hybridization. In addition, virus-induced gene silencing analysis revealed that CsHOMEOBOX3 (CsHOX3) and CsbHLH1 are involved in nonglandular trichome elongation and glandular trichome formation, respectively, which corresponds with the transcriptome data. This study presents a transcriptome atlas that provides insights into the molecular processes involved in multicellular trichome formation in cucumber and can be an important resource for future functional studies.
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Arabidopsis , Cucumis sativus , Arabidopsis/genética , Cucumis sativus/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Transcriptoma/genética , Tricomas/genéticaRESUMEN
Invited for the cover of this issue are Prof. Wenjing Tian and co-workers at Jilin University. The image depicts the highly sensitive piezochromic fluorescence switching of tetraphenylethylene-anthraquinone under low-pressure regimes (â¼60â kPa). Read the full text of the article at 10.1002/chem.202301070.
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Sensing of low-pressure signals is of great importance for cutting-edge technologies. Organic piezochromic molecules offer a promising library of pressure sensitive materials which can be tailor-designed toward specific requirements. However, very few examples of low-pressure sensitive piezochromic fluorescent molecules have been obtained till date, and the underlying mechanisms are still in its infancy. Herein, we report highly sensitive piezochromic fluorescent switching under low-pressure regimes (â¼60â kPa) of tetraphenylethylene-anthraquinone (TPE-AQ) based on the controlled molecular design and polymorphic phase strategy. The influence of both intramolecular conformation effect and variations of intermolecular stacking modes on the piezochromic property of TPE-AQ is investigated. The underlying mechanism of the low-pressure sensitive piezochromic fluorescence switching is demonstrated to be closely related to the loosely packed molecular orientation, as confirmed by X-ray diffraction measurements combined with simulations. This work provides a way to design highly efficient pressure sensors based on organic molecular systems.
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Enhancing the dissymmetry factor (glum ) is a crucial issue in developing circularly polarized luminescence (CPL) materials. Herein, based on supramolecular self-assembly of diethyl l-glutamate-cyanodiarylethene (L-GC) in mixed solution of EtOH-H2 O with different water fraction, enhanced circularly polarized emission from pulsating nanotubules is realized. In the mixture of ethanol and water (30/70, v/v), L-GC self-assembles into roll-up-type dense nanotubes and shows l-CPL. Remarkably, by increasing the water fraction to 80% and 90%, the diameter of the roll-up nanotubes increases and the dissymmetry factor of the nanotubes is significantly enhanced from 6.9 × 10-3 (dense nanotubes) to 3.7 × 10-2 (loose nanotubes) because of the enhanced intermolecular interactions and more ordered supramolecular stacking when increasing the water fraction. An efficient way is provided here to realize the increase of the dissymmetry factor by only changing the composition of solvents.
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Luminiscencia , Nanotubos , Etanol , Solventes , AguaRESUMEN
Radioactive iodine-capturing materials are urgently needed for the emerging challenges in nuclear waste disposal. The various pore structures of covalent organic frameworks (COFs) render them promising candidates for efficient iodine adsorption. However, the detailed structure-property relationship of COFs in iodine adsorption remains elusive. Herein, two polymorphic COFs with significantly different crystalline structures are obtained based on the same building blocks with varied molecular ratios. The two COFs both have high crystallinity, high specific surface area, and excellent chemical and thermal stability. Compared with the [C4+C4] topology (PyT-2) with an AA stacking form, the [C4+C2] topology (PyT-1) with an AB stacking form has more twisted pore channels and complex ink-bottle pores. At ambient conditions, PyT-1 and PyT-2 both exhibit good adsorption properties for iodine capture either in a gaseous or liquid medium. Remarkably, PyT-1 presents an excellent maximum adsorption capacity (0.635 g g-1), and the adsorption limit of PyT-2 is 0.445 g g-1 in an n-hexane solution with an iodine concentration of 400 mg L-1, which is highly comparable to the state-of-the-art iodine absorption performance. This study provides a guide for the future molecular design strategy toward novel iodine adsorbents.
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A three-dimensional spatial bubble counting method is proposed to solve the problem of the existing crucible bubble detection only being able to perform two-dimensional statistics. First, spatial video images of the transparent layer of the crucible are acquired by a digital microscope, and a quartz crucible bubble dataset is constructed independently. Secondly, to address the problems of poor real-time and the insufficient small-target detection capability of existing methods for quartz crucible bubble detection, rich detailed feature information is retained by reducing the depth of down-sampling in the YOLOv5 network structure. In the neck, the dilated convolution algorithm is used to increase the feature map perceptual field to achieve the extraction of global semantic features; in front of the detection layer, an effective channel attention network (ECA-Net) mechanism is added to improve the capability of expressing significant channel characteristics. Furthermore, a tracking algorithm based on Kalman filtering and Hungarian matching is presented for bubble counting in crucible space. The experimental results demonstrate that the detector algorithm presented in this paper can effectively reduce the missed detection rate of tiny bubbles and increase the average detection precision from 96.27% to 98.76% while reducing weight by half and reaching a speed of 82 FPS. The excellent detector performance improves the tracker's accuracy significantly, allowing for real-time and high-precision counting of bubbles in quartz crucibles. It is an effective method for detecting crucible spatial bubbles.
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Algoritmos , Cuarzo , SemánticaRESUMEN
In photoswitches that undergo fluorescence switching upon ultraviolet irradiation, photoluminescence and photoisomerization often occur simultaneously, leading to unstable fluorescence properties. Here, we successfully demonstrated reversible solid-state triple fluorescence switching through "Pump-Trigger" multiphoton manipulation. A novel fluorescence photoswitch, BOSA-SP, achieved green, yellow, and red fluorescence under excitation by pump light and isomerization induced by trigger light. The energy ranges of photoexcitation and photoisomerization did not overlap, enabling appropriate selection of the multiphoton light for "pump" and "trigger" photoswitching, respectively. Additionally, the large free volume of the spiropyran (SP) moiety in the solid state promoted reversible photoisomerization. Switching between "pump" and "trigger" light is useful for three-color tunable switching cell imaging, which can be exploited in programmable fluorescence switching. Furthermore, we exploited reversible dual-fluorescence switching in a single molecular system to successfully achieve two-color super-resolution imaging.
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Rayos Ultravioleta , Microscopía FluorescenteRESUMEN
Covalent organic frameworks (COFs) have potential applications in gas storage, catalysis, proton conduction, sensing, and chemical removal etc., due to their highly crystalline structure, good stability, porosity, as well as structural and functional controllability. Herein, by using electron-rich group, 2,5-bis(methylthio)terephthalaldehyde (BMTA), and electron-deficient group, 1,3,5-tris-(4-aminophenyl)triazine (TAPT) as building blocks, TAPT-BMTA-COF is constructed through Schiff-base reaction. TAPT-BMTA-COF has high crystallinity, porosity, big Brunauer-Emmett-Teller surface area (BET), good chemical and thermal stability, and commendable solvatochromic properties. It can be used as the water sensing scaffold to detect the trace water in organic solvents due to the fluorescence quenching of the COF caused by the interaction between water and TAPT-BMTA-COF.
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Estructuras Metalorgánicas , Catálisis , Electrones , Porosidad , AguaRESUMEN
Objective: This study was conducted to explore the risk factors for the prognosis and recurrence of ureteropelvic junction obstruction (UPJO). Methods: The correlation of these variables with the prognosis and recurrence risks was analyzed by binary and multivariate logistic regression. Besides, a nomogram was constructed based on the multivariate logistic regression calculation. After the model was verified by the C-statistic, the ROC curve was plotted to evaluate the sensitivity of the model. Finally, the decision curve analysis (DCA) was conducted to estimate the clinical benefits and losses of intervention measures under a series of risk thresholds. Results: Preoperative automated peritoneal dialysis (APD), preoperative urinary tract infection (UTI), preoperative renal parenchymal thickness (RPT), Mayo adhesive probability (MAP) score, and surgeon proficiency were the high-risk factors for the prognosis and recurrence of UPJO. In addition, a nomogram was constructed based on the above 5 variables. The area under the curve (AUC) was 0.8831 after self cross-validation, which validated that the specificity of the model was favorable. Conclusion: The column chart constructed by five factors has good predictive ability for the prognosis and recurrence of UPJO, which may provide more reasonable guidance for the clinical diagnosis and treatment of this disease.
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Bama County is a world-famous longevity county in the Guangxi Province, China. Bama hemp is a traditional seed used in hemp cultivation in the Bama County. The seeds contain abundant unsaturated fatty acids, particularly linoleic acid (LA) and linolenic acid in the golden ratio. These two substances have been proven to be related to human health and the prevention of various diseases. However, the seed development and seed oil accumulation mechanisms remain unclear. This study employed a combined analysis of physiological, transcriptomic, and metabolomic parameters to elucidate the fatty acid formation patterns in Bama hemp seeds throughout development. We found that seed oil accumulated at a late stage in embryo development, with seed oil accumulation following an "Sâ³-shaped growth curve, and positively correlated with seed size, sugar content, protein content, and starch content. Transcriptome analysis identified genes related to the metabolism of LA, α-linolenic acid (ALA), and jasmonic acid (JA). We found that the FAD2 gene was upregulated 165.26 folds and the FAD3 gene was downregulated 6.15 folds at day 21. Metabolomic changes in LA, ALA, and JA compounds suggested a competitive relationship among these substances. Our findings indicate that the peak period of substance accumulation and nutrient accumulation in Bama hemp seeds occurs during the midstage of seed development (day 21) rather than in the late stage (day 40). The results of this research will provide a theoretical basis for local cultivation and deep processing of Bama hemp.
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Cannabis , Regulación de la Expresión Génica de las Plantas , Ácido Linoleico , Metabolómica , Proteínas de Plantas , Semillas , Transcriptoma , Ácido alfa-Linolénico , Semillas/metabolismo , Semillas/crecimiento & desarrollo , Semillas/genética , Semillas/química , Ácido alfa-Linolénico/metabolismo , Cannabis/genética , Cannabis/crecimiento & desarrollo , Cannabis/metabolismo , Cannabis/química , Ácido Linoleico/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , China , Perfilación de la Expresión GénicaRESUMEN
Light is a basic requirement to drive carbon metabolism in plants and supports life on earth. Spectral quality greatly affects plant morphology, physiology, and metabolism of various biochemical pathways. Among visible light spectrum, red, blue, and green light wavelengths affect several mechanisms to contribute in plant growth and productivity. In addition, supplementation of red, blue, or green light with other wavelengths showed vivid effects on the plant biology. However, response of plants differs in different species and growing conditions. This review article provides a detailed view and interpretation of existing knowledge and clarifies underlying mechanisms that how red, blue, and green light spectra affect plant morpho-physiological, biochemical, and molecular parameters to make a significant contribution towards improved crop production, fruit quality, disease control, phytoremediation potential, and resource use efficiency.
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Luz Verde , Plantas , Fenómenos Fisiológicos de las Plantas , Desarrollo de la Planta , LuzRESUMEN
BACKGROUND: To explore the potential role of m6A methylation modification in Wilms Tumor (WT) by m6A-RNA Methylation (m6A) regulators. METHODOLOGY: The association of m6A modification patterns with immune and prognostic characteristics of tumors was systematically evaluated using 19 m6A regulators extracted from Wilms Tumor's samples in public databases. A comprehensive model of "m6Ascore" was constructed using principal component analysis, and its prognostic value was evaluated. RESULTS: Almost all m6A regulators were differentially expressed between WT and normal tissues. Unsupervised clustering identified three distinct m6A clusters that differed in both immune cell infiltration and biological pathways. The m6Ascore was constructed to quantify m6A modifications in individual patients. Our analysis suggests that m6Ascore is an independent prognostic factor for WT and can be used as a novel predictor of WT prognosis. CONCLUSIONS: This study comprehensively explored and systematically characterized m6A modifications in WT. m6A modification patterns play a critical role in the tumor immune microenvironment (TIME) and WT prognosis. m6Ascore provides a more comprehensive understanding of m6A modifications in WT and offers a practical tool for predicting WT prognosis. This study will help clinicians to identify valid indicators of WT to improve the poor prognosis of this disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://www.aliyundrive.com/drive/folder/64be739cd6956a741fb24670baeea53422be6024 .
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Neoplasias Renales , Tumor de Wilms , Humanos , Metilación , Pronóstico , Tumor de Wilms/genética , Neoplasias Renales/genética , ARN , Microambiente TumoralRESUMEN
Objectives: Studies have demonstrated that students are able to improve their understanding of anatomy, physical exam skills, and clinical knowledge when ultrasound is incorporated into their education. This study investigates whether students enrolled in an elective with significant use of ultrasound (ACS) in their preclinical years subjectively improved their preparedness for clinical rotations, residency, and learning in several subjects. Methods: This was a retrospective analysis of an anonymous online needs assessment survey sent to 384 third- and fourth-year medical students. Survey items included Likert scales analyzed with a student's t-test or Chi-Square analysis and yes/no questions analyzed with Chi square, as well as demographic information. Results: 201 students responded to the survey (52.3% response rate). ACS participants reported feeling more prepared for their clinical rotations than their non-ACS peers (3.5 vs. 2.33, p < 0.001 ) and felt more prepared for residency (3.12 vs 1.91, p < 0.001). ACS students also found ultrasound significantly more helpful in understanding the physical exam (69.3% vs. 53.2%, p = 0.02) and anatomy (94.7% vs. 81%, p = 0.012). Conclusions: Student respondents expressed a desire for more ultrasound education throughout medical school. Students who participated in ACS reported feeling more prepared for their clinical rotations and residency than their non-ACS peers and were more likely to feel that ultrasound improved their understanding of anatomy and the physical exam. This study adds to the literature suggesting that increasing the quantity of ultrasound in preclinical medical education may improve students' satisfaction, learning and clinical preparedness. Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-023-01800-4.
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It is highly challenging to achieve circularly polarized luminescence (CPL) switching by precisely tuning supramolecular interactions and unveiling the mechanism of supramolecular chirality inversion. Herein, we demonstrated CPL switching based on diethyl l-glutamate-9-cyanophenanthrene (LGCP) and diethyl l-glutamate-pyrene (LGP) via the precise regulation of supramolecular interactions. LGCP assembly driven by hydrogen bonding showed right CPL, while LGP assembly driven by π-π interaction led to left CPL. Remarkably, significant CPL switching was observed from the assemblies of LGCP/octafluoronaphthalene (OFN), attributed to the alteration of the dominating interaction from weak hydrogen bonding to rather strong π-π interaction, while the assemblies of LGP/OFN exhibited minimum CPL variation because the dominating π-π interaction within the assembly of LGP/OFN illustrated quite limited variations upon arene-perfluoroarene interaction. This work provides a feasible strategy toward the efficient modulation of the chiroptical properties of multiple component supramolecular systems, meanwhile offering possibilities for the mechanism exploration of the chirality inversion of supramolecular assemblies.
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Intercropping is considered a sustainable agricultural practice that can reduce the environmental impacts on agriculture. Our study investigated the morphology, physiology, and cadmium (Cd) and lead (Pb) uptake of kenaf (Hibiscus cannabinus L.) and soybean (Glycine max L.) under intercropping in mining soil. Results showed that mutual intercropping is conducive to the growth and biomass accumulation of kenaf and soybean, compared to their respective monoculture. Intercropping increased the relative chlorophyll index in kenaf, while that in soybean had no significant effect. Furthermore, intercropping increased the antioxidant enzyme activity of kenaf, while that of soybean reduced or had no significant effect. The content of malondialdehyde (MDA) was decreased in both of the species. Compared to their respective monoculture, Cd content was increased in kenaf leaves and reduced in soybean roots. Moreover, intercropping decreased the Pb content in tissues of both the species, except that Pb content of kenaf roots was increased. At the same time, root, leaf, or stem bioconcentration factors also performed the same trend, and TF was less than 1. These results indicated that intercropping can increase the plant growth and decrease the metal content in plant tissues. Present findings could provide support for future research on kenaf and soybean cultivation in contaminated lands. In addition, the present study strengthens our understanding about the effectiveness of intercropping system on heavy metal-contaminated lands for sustainable agricultural production.
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Hibiscus , Contaminantes del Suelo , Cadmio/análisis , Glycine max , Antioxidantes , Plomo , Contaminantes del Suelo/análisis , Biodegradación Ambiental , Suelo , Raíces de Plantas/químicaRESUMEN
Artificial multi-enzyme cascades bear great potential for bioconversion of C1 compounds to value-added chemicals. Over the past decade, massive efforts have been devoted to constructing multi-enzyme cascades to produce glycolic acid, rare functional sugars and even starch from C1 compounds. However, in contrast to traditional fermentation utilizing C1 compounds with the expectation of competitive economic performance in future industrialization, multi-enzyme cascades systems in the proof-of-concept phase are facing the challenges of upscaling. Here, we offered an overview of the recent advances in the construction of in vitro multi-enzyme cascades and whole-cell transformation using C1 compounds as substrate. In addition, the existing challenges and possible solutions were also discussed aiming to combine the strengths of in vitro and in vivo multi-enzyme cascades systems for upscaling.
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OBJECTIVE: To evaluate the efficacy, safety and survival of combination of carboplatin plus paclitaxel as neoadjuvant chemotherapy (NACT) for patients with locally advanced triple-negative breast cancer (TNBC), and explore an optimal regimen for TNBC. METHODS: Patients with core needle biopsy confirmed pathological diagnosis of IIA â¼ IIIC invasive breast cancer, negative for estrogen and progesterone receptors and HER2 by immunohistochemistry, and with indication for NACT were eligible in this study. The biopsy tumor tissues were tested for CK5/6, CK14, EGFR and Ki67. The patients received paclitaxel 175 mg/m(2) on day 1, carboplatin at an area under the curve 5 mg×min/ml on day 2 of every 21 days. The clinical response was evaluated every 2 cycles according to Standard RECIST 1.0 criteria and surgery was done after four to six cycles. Pathological complete remission (pCR) was defined if absence of invasive tumor in the breast and axillary lymph nodes samples or residual carcinoma in situ only. RESULTS: Overall, thirty-one patients were enrolled from January 2008 to November 2010. The median age was 51 years and 83.9% of the patients were diagnosed as stage IIB to IIIC diseases. 30 Patients completed chemotherapy as planed while one patient changed regimen due to paclitaxel allergy. Twenty-eight patients could be evaluated for clinical efficacy, of which CR, PR, SD, PD were achieved in 4, 20, 3 and 1 women, respectively. The objective response rate was 85.7%. The expression rate of CK5/6, CK14 and EGFR were 88.9% (24/27), 59.3% (16/27) and 63% (17/27), respectively. Among 27 patients who received modified radical mastectomy or breast-conserving surgery, 11 patients obtained pCR, with a pCR rate of 40.7% (95%CI 22.2% - 59.3%). Five of six CK5/6- and CK14-positive patients achieved pCR. All the 31 patients could be evaluated for toxicity according to the NCI-CTC v3.0 criteria. The major toxicities were neutropenia (93.5%), vomiting (45.2%) and ALT/AST increase (32.3%), and grade 3-4 toxicities accounted for 74.2%, 3.2%, 0, respectively. Until December 2011, at a median follow-up of 28.9 months (range 5 - 47.9), eight patients developed recurrence including 5 patients died. Among 11 patients with pCR, one suffered from lung metastasis at 45 months after diagnosis and survived with tumor until now. The other ten were alive and disease free. The 3-year DFS and OS were 62% and 74.7%, respectively. CONCLUSIONS: As a neoadjuvant treatment for triple-negative breast cancer, carboplatin plus paclitaxel regimen achieves notable higher objective response rate and pCR rate compared with the anthracycline plus paclitaxel regimen reported in the literature, and is well tolerable. It is an optimized regimen for TNBC.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Carboplatino/administración & dosificación , Carcinoma Ductal de Mama/tratamiento farmacológico , Paclitaxel/administración & dosificación , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Biopsia con Aguja Gruesa , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Carcinoma Ductal de Mama/metabolismo , Carcinoma Ductal de Mama/patología , Quimioterapia Adyuvante , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Neoplasias Pulmonares/secundario , Persona de Mediana Edad , Terapia Neoadyuvante , Recurrencia Local de Neoplasia , Estadificación de Neoplasias , Neutropenia/inducido químicamente , Receptor ErbB-2/metabolismo , Receptores de Estrógenos/metabolismo , Receptores de Progesterona/metabolismo , Inducción de Remisión , Tasa de Supervivencia , Adulto JovenRESUMEN
Replant disease caused by continuous cropping obstacles commonly occurs in a Lilium brownii consecutive monoculture. To reveal the mechanisms contributing to the continuous cropping obstacles of L. brownii, four cropping patterns (fallow, L. brownii-rice rotation, newly planted L. brownii, and 2-year L. brownii consecutive monoculture) were designed, and Illumina MiSeq (16S rDNA and ITS) was utilized to detect shifts in the microbial community in the rhizosphere. Our result showed that planting of L. brownii significantly reduced soil pH. Consecutive monoculture of L. brownii can significantly decrease the diversity and abundance of soil bacteria, but markedly increase the diversity and abundance of soil fungi. Under the four planting pattern treatments, the changes in soil pH were consistent with the changes in the Shannon diversity index of soil bacterial communities, whereas we observed a negative correlation between soil pH and Shannon diversity index for fungi. The relative abundance of Lactobacillales significantly increased in soils of L. brownii consecutive monoculture, while Acidobacteriales, Solibacterales, and Xanthomonadales increased in soils of L. brownii-rice rotation and newly planted L. brownii. Collectively, this work aimed to elucidate the relationship between the L. brownii planting patterns and soil microbiome, thereby providing a theoretical basis for screening new biological agents that may contribute to resolving continuous cropping obstacles of L. brownii.
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Objective: This study aims to identify whether the specialty-oriented case-based learning (CBL) pedagogy contributes to the teaching of basic theory and practical operation in undergraduate clinical teaching in pediatric surgery, and to assess the satisfaction of undergraduates. Methods: A total of 72 undergraduates in Grade 2016 who interned at Qilu Hospital of Shandong University were enrolled in this study. All these undergraduates voluntarily participated in this experimental study. They were randomly divided into the experimental group (the CBL group, n = 36) and the control group [the traditional lecture-based learning (LBL) group, n = 36] with the assistance of random number tables. In the control group, a traditional pedagogy was adopted and the knowledge in the textbook was explained according to the syllabus. In the experimental group, a specialty-oriented CBL pedagogy was adopted under the guidance of clinical instructors. After the teaching, a comparison was drawn between both groups in respect of the theoretical exam and practical exam scores. In addition, the teaching results were evaluated by a questionnaire survey. Results: The average theoretical exam scores and comprehensive scores of undergraduates in the CBL group were higher than those in the LBL group (P < 0.05). There was no significant difference in the practical exam scores between the CBL group and the LBL group (P > 0.05). However, those undergraduates in the CBL group attained higher scores in doctor-patient communication and perioperative diagnosis and treatment (P < 0.05). According to the questionnaire survey, the undergraduates in the CBL group had higher satisfaction than those in the LBL group. Besides, this specialty-oriented CBL pedagogy had higher performance in improving their ability to solve problems independently and cultivating and expanding their knowledge compared with the traditional pedagogy. Meanwhile, this specialty-oriented CBL pedagogy can cultivate the critical thinking of undergraduates, which could increase their learning efficiency and improve their interest in learning. Conclusion: This specialty-oriented CBL pedagogy could improve the mastery of professional knowledge, course satisfaction, doctor-patient communication ability in clinical practice, and perioperative diagnosis and treatment ability of these undergraduates. Therefore, it is worthwhile to recommend and popularize this pedagogy in undergraduate clinical teaching in pediatric surgery.
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In this paper the development of a physically consistent phase-field theory of solidification shrinkage is presented. The coarse-grained hydrodynamic equations are derived directly from the N-body Hamiltonian equations in the framework of statistical physics, while the constitutive relations are developed in the framework of the standard phase-field theory, by following the variational formalism and the principles of non-equilibrium thermodynamics. To enhance the numerical practicality of the model, quasi-incompressible hydrodynamic equations are derived, where sound waves are absent (but density change is still possible), and therefore the time scale of solidification is accessible in numerical simulations. The model development is followed by a comprehensive mathematical analysis of the equilibrium and propagating one-dimensional solid-liquid interfaces for different density-phase couplings. It is shown, that the fluid flow decelerates/accelerates the solidification front in case of shrinkage/expansion of the solid compared to the case when no density contrast is present between the phases. Furthermore, such a free energy construction is proposed, in which the shape of the equilibrium planar phase-field interface is independent from the density-phase coupling, and the equilibrium interface represents an exact propagating planar interface solution of the quasi-incompressible hydrodynamic equations. Our results are in agreement with previous theoretical predictions.