Accuracy and Error Sources of the Rietveld Full Pattern Fitting Method in Quantitative Analysis of Illite Ores

BACKGROUND: Illite is an important mineral resource. It is of great theoretical and practical significance to accurately obtain the mineral composition and content of illite ores. The Rietveld full pattern fitting method uses the whole diffraction pattern for analysis and shows high accuracy. However, due to the lack of pure illite samples, the accuracy and error sources of this method for analyzing the content of illite ores are not clearly known at present.OBJECTIVES: To understand the accuracy and error sources of the Rietveld full pattern fitting method in quantitative analysis of illite ores.METHODS: The Rietveld full pattern fitting method was used to quantitatively analyze artificial and natural illite ore samples. The results of X-ray fluorescence spectrometry (XRF) of natural illite ores were compared with the chemical compositions calculated from the mineral contents by the Rietveld method.RESULTS: The results showed that the maximum absolute error ranges of illite-quartz binary mixtures, illite-quartz-albite ternary mixtures, and illite-quartz-albite-calcite-kaolinite multiple mixtures were -0.9%-0.9%, -1.9%-1.6%, and -2.3%-1.6%, respectively. The chemical compositions of natural illite ores calculated by Rietveld method were in good agreement with the results of XRF. This indicated that the Rietveld method had high accuracy in the quantitative analysis of mineral contents of natural illite ore samples. The error sources were mainly affected by the illite structural model, atomic thermal displacement parameters Uiso, and preferred orientation.CONCLUSIONS: A reasonable structural model of illite should be chosen according to the actual samples. The values of atomic thermal vibration Uiso should be reasonably set according to the references. Preferred orientation should be decreased as much as possible during the sample preparation

Exercise postconditioning reduces ischemic injury via suppression of cerebral gluconeogenesis in rats

Abstract Pre‐stroke exercise conditioning reduces neurovascular injury and improves functional outcomes after stroke. The goal of this study was to explore if post‐stroke exercise conditioning (PostE) reduced brain injury and whether it was associated with the regulation of gluconeogenesis. Adult rats received 2 h of middle cerebral artery (MCA) occlusion, followed by 24 h of reperfusion. Treadmill activity was then initiated 24 h after reperfusion for PostE. The severity of the brain damage was determined by infarct volume, apoptotic cell death, and neurological deficit at one and three days after reperfusion. We measured gluconeogenesis including oxaloacetate (OAA), phosphoenolpyruvate (PEP), pyruvic acid, lactate, ROS, and glucose via ELISA, as well as the location and expression of the key enzyme phosphoenolpyruvate carboxykinase (PCK)‐1/2 via immunofluorescence. We also determined upstream pathways including forkhead transcription factor (FoxO1), p‐FoxO1, 3‐kinase (PI3K)/Akt, and p‐PI3K/Akt via Western blot. Additionally, the cytoplasmic expression of p‐FoxO1 was detected by immunofluorescence. Compared to non‐exercise control, PostE (*p < .05) decreased brain infarct volumes, neurological deficits, and cell death at one and three days. PostE groups (*p < .05) saw increases in OAA and decreases in PEP, pyruvic acid, lactate, ROS, glucose levels, and tissue PCKs expression on both days. PCK‐1/2 expressions were also significantly (*p < .05) suppressed by the exercise setting. Additionally, phosphorylated PI3K, AKT, and FoxO1 protein expression were significantly induced by PostE at one and three days (*p < .05). In this study, PostE reduced brain injury after stroke, in association with activated PI3K/AKT/FoxO1 signaling, and inhibited gluconeogenesis. These results suggest the involvement of FoxO1 regulation of gluconeogenesis underlying post‐stroke neuroprotection

Generation of male germ cells from mouse induced pluripotent stem cells in vitro

Germ cells are the only cell type that passes genetic information to the next generation. In most metazoan species, primordial germ cells (PGCs) were induced from epiblasts by signals from the neighboring tissues. In vitro derivation of germ cells from the pluripotent stem cells (PSCs) such as embryonic stem cells (ESCs) and induced PSCs (iPSCs) are of great values for the treatment of infertility, for animal breeding, and for studying the mechanism of germ cell development. Although the derivations of male germ cells from PSCs have been previously reported, most of the studies failed to conduct the induction in a well-controlled and highly efficient manner. Here, we report the derivation of induced PGC-like cells (iPGCLCs) from mouse iPSCs via induced epiblast-like cells (iEpiLCs) as being monitored by the expression of enhanced green fluorescent protein gene under the control of the promoter of stimulated by retinoic acid 8 (Stra8-EGFP). The identity of iPGCLCs was characterized by examining the expression of multiple marker genes as well as by the recovery of spermatogenesis after they were transplanted to the testis of infertile W/Wv mice. Furthermore, iPGCLCs were either induced to germline stem cell-like cells (iGSCLCs) or reverted back to embryonic germ cell-like cells (iEGCLCs). In conclusion, we have established an efficient procedure for inducing iPSCs into iPGCLCs that can be further expanded and induced to more developed germ cells. This work indicates that the technology of in vitro germ cell induction is becoming more sophisticated and can be further improved

Transformation of boehmite into 2:1 type layered aluminosilicates with different layer charges under hydrothermal conditions

In this study, beidellite, paragonite and other 2:1 type layered aluminosilicates with high layer charges (2:1 type LA-HLC) were synthesized under hydrothermal conditions by using boehmite as a precursor. The concentrations of dissolved Al from boehmite precursor had important effects on the mineral components of the hydrothermal products and the layer charge density of the resultant minerals. A combination of 2:1 type LA-HLC, paragonite, and minor beidellite formed at a relatively high concentration of dissolved Al, while beidellite with a small amount of 2:1 type LA-HLC was produced at a low concentration of dissolved Al. The resultant 2:1 type LA-HLC exhibited poor swelling ability when treated with ethylene glycol. A solid-state transformation mechanism was proposed for the transformation based on the HRTEM images and EDS analyses, which showed that lattice fringes representing (001) faces of 2:1 type layered aluminosilicates (2:1 type LA) were parallel to the (020) direction of boehmite. The successful transformation of boehmite into 2:1 type LA provides insights to well understand the formation of 2:1 type LA in geological processes and offer a facile preparation approach for the synthesis of 2:1 type LA with different layer charges

Application of multiple interactive teaching methods in clinical nursing teaching (多元互动式教学方法在临床护理教学中的应用)

Objective To evaluate the application of multiple interactive teaching methods in clinical nursing teaching and practice. Methods From August 2021 to April 2022, a total of 96 nursing students who participated in the internship in the hospital were selected as the research objects, and were randomly divided into the control group and observation group, with 48 nursing students in each group. The conventional teaching method was used in the control group, while the multiple interactive teaching method was adopted in the observation group. The theoretical knowledge, operational skills and satisfaction with different teaching methods were compared between the two groups, and the application effect of different teaching methods was comprehensively analyzed. Results Scores of theoretical knowledge test and practice skills assessment in the observation group were higher than those in the control group, with a significant difference (P＜0. 01). The score of satisfaction assessment in the observation group was higher than those in the control group, with a significant difference (P＜0. 01). Conclusion The multi-interactive teaching model can deepen the learning of theoretical knowledge and improve the comprehensive quality of nursing students. (目的 研究多元互动式教学方法在临床护理教学实践中的应用效果。方法 选取2021年8月—2022年4月在北京中医药大学东方医院实习的96名实习护生为研究对象, 随机分为两组: 对照组48名实习护生, 采用常规方法教学; 观察组48名实习护生, 接受多元互动式教学。对比两组实习护生理论知识和操作技能考核成绩, 评价实习护生对不同教学方法的满意程度, 综合分析不同教学方法的应用效果。结果 观察组护生理论知识和操作技能成绩高于对照组, 差异有统计学意义(P＜0. 01)。观察组护生对教学方法的满意度评分高于对照组, 差异有统计学意义(P＜0. 01)。结论 多元互动教学模式可以加深护生对理论知识的学习效果, 提升其综合素质, 教学效果明确。

Conversion of serpentine to smectite under hydrothermal condition: Implication for solid-state transformation

Understanding clay mineral transformation is of fundamental importance to grasping phyllosilicate crystal chemistry and unraveling geochemical processes. In this study, hydrothermal experiments were conducted on lizardite and antigorite, to investigate the possibility of the transformation from serpentine to smectite, the effect of precursor minerals' structure on the transformation and the transformation mechanism involved. The reaction products were characterized using XRD, TG, HRTEM, and Al-27 MAS NMR. The results show that both lizardite and antigorite can be converted to smectite, but such conversion is much more difficult than that of kaolinite group minerals. The successful transformation is mainly evidenced by the occurrence of the characteristic (001) reflection of smectite at 1.2-1.3 nm in the XRD patterns and smectite layers with a thickness of 1.2-1.3 nm in HRTEM images of hydrothermal products as well as the dehydroxylation of the newly formed smectite at a higher temperature in comparison to that of the starting minerals. The difficulty for the transformation of serpentine to smectite may be due to the lack of enough available Al in the reaction system, in which the substitution of Al3+ for Si4+ in the neo-formed tetrahedral sheet is critical to control the size matching between the neo-formed tetrahedral sheet and octahedral sheet in starting minerals. Since the neighboring layers in antigorite are linked by the strong Si-O covalent bonds, the transformation only takes place at the edges of an antigorite layer rather than the whole layer, and the neo-formed smectite is non-swelling due to the inheritance of such Si-O covalent bonds. The conversion of lizardite to smectite is more feasible than that of antigorite, accompanied by exfoliation. This leads to a prominent decrease of the particle size in the hydrothermal products and the number of phyllosilicate layers contained therein. Two dominant pathways were observed for the transformation of lizardite and antigorite into smectite, i.e., conversion of one serpentine layer to one smectite layer via attachment of Si-O tetrahedra onto the octahedral sheet surface of the starting minerals and two adjacent serpentine layers merging into one smectite layer. In the case of the latter, dissolution of octahedra and inversion of tetrahedral sheets took place during the transformation. Besides these two dominant pathways, precipitation and epitaxial growth of smectite were also observed in the cases of lizardite and antigorite, respectively. The present study suggests that solid-state transformation is the main mechanism for conversion of serpentine minerals to smectite, similar to the transformation of kaolinite group minerals to beidellite

EZH2 K63-polyubiquitination affecting migration in extranodal natural killer/T-cell lymphoma

Abstract Background Overexpressed EZH2 is oncogenically involved in the pathogenesis of different cancerous contexts including extranodal natural killer/T cell lymphoma (ENKTL). However, the underlying mechanisms of EZH2 upregulation have not been fully clarified and it is still difficult to target EZH2 in ENKTL. Results Current study identifies an E3 ligase TRIP12 that triggers K63-linked polyubiquitination of EZH2 in ENKTL and unexpectedly, stabilizes EZH2. As determined by gene expression profiling (GEP), TRIP12 and EZH2 levels correlate with each other in ENKTL patient samples. Aided by quantitative mass spectrometry (MS) and follow-up analysis, we identify K634 as the ubiquitination site of EZH2. Further study confirms that TRIP12-mediated EZH2 K634 ubiquitination enhances the interaction between EZH2 and SUZ12 or CDK1 and increases the level of EZH2 T487 phosphorylation. This study further demonstrates the TRIP12-EZH2 signaling might be regulated by cytoplasmic HSP60. Importantly, the TRIP12-EZH2 axis mediates ENKTL cell migration via accelerating epithelial-mesenchymal transition (EMT). Moreover, our study finds out dexamethasone treatment manipulates TRIP12-EZH2 signaling and may represent a novel therapeutic strategy against ENKTL metastasis. Conclusions Altogether, TRIP12 induces K63-linked site-specific polyubiquitination of EZH2 for stabilization, which promotes ENKTL cell migration and could be targeted by dexamethasone treatment

The prognostic and therapeutic implications of circulating tumor cell phenotype detection based on epithelial–mesenchymal transition markers in the first-line chemotherapy of HER2-negative metastatic breast cancer

Abstract Background Epithelial–mesenchymal transition (EMT) is implicated in the metastatic process and presents a challenge to epithelial cell adhesion molecule-based detection of circulating tumor cells (CTCs), which have been demonstrated to be a prognostic indicator in metastatic breast cancer. Although evidence has indicated that heterogeneity of CTCs based on EMT markers is associated with disease progression, no standard recommendations have been established for clinical practice. This study aimed to evaluate the prognostic significance of dynamic CTC detection based on EMT for metastatic breast cancer patients. Methods We enrolled 108 human epidermal growth factor receptor 2-negative metastatic breast cancer patients from the prospective phase III CAMELLIA study and applied the CanPatrol CTC enrichment technique to identify CTC phenotypes (including epithelial CTCs, biphenotypic epithelial/mesenchymal CTCs, and mesenchymal CTCs) in peripheral blood samples. Receiver operating characteristic curve analyses of total CTC count and the proportion of mesenchymal CTCs for predicting the 1-year progression-free survival (PFS) rate were conducted to determine the optimal cut-off values, and Kaplan–Meier analysis and Cox proportional hazards regression analysis were performed to investigate the prognostic value of the cut-off values of both total CTC count and the proportion of mesenchymal CTCs in combination. Results For predicting the 1-year PFS rate, the optimal cut-off value of total CTC count was 9.5 (Area under the curve [AUC] = 0.538, 95% confidence interval [CI] = 0.418–0.657), and that of the proportion of mesenchymal CTCs was 10.7% (AUC = 0.581, 95% CI = 0.463–0.699). We used the two cut-off values in combination to forecast PFS in which the total CTC count was equaled to or exceeded 10/5 mL with the proportion of mesenchymal CTCs surpassed 10.7%. Patients who met the combined criteria had significantly shorter median PFS than did those who did not meet the criteria (6.2 vs. 9.9 months, P =0.010). A nomogram was constructed based on the criteria and significant clinicopathological characteristics with a C-index of 0.613 (P = 0.010). Conclusions The criteria, which combine the total CTC count and the proportion of mesenchymal CTCs, may be used to monitor therapeutic resistance and predict prognosis in patients with metastatic breast cancer. Trial registration ClinicalTrials.gov. NCT01917279. Registered on 19 July 2013, https://clinicaltrials.gov/ct2/show/NCT01917279?term=NCT01917279&rank=1