Ultrasound Pretreatment for Enhancing Fine and Ultrafine Flake Graphite Flotation Beneficiation.

With the severe depletion of coarse flake graphite (a critical raw material) resources, developing and utilizing fine and ultrafine graphite resources have recently attracted attention. Froth flotation is a widely used technique for the initial enrichment of graphite; however, the flotation selectivity decreases significantly along with particle size reduction. Ultrasound pretreatment would be a promising method to improve the flotation of fine particles. As an innovative approach to understand better the flotation response of different flake graphite sizes, this study conducted a comparative analysis based on flotation concentrate yield and ash as well as ash removal rate between the flake graphite with various particle sizes after ultrasound pretreatment. Particle size, X-ray powder diffraction, and scanning electron microscopy and energy dispersive X-ray spectroscopy analyses were used to investigate the effect of ultrasound treatment on mineralogical properties of the flake graphite with varied particle sizes. Process outcomes indicated that the flotation performance of fine flake graphite (mean chord length: 62.63 µm) was significantly enhanced after ultrasound pretreatment. However, flotation of the ultrafine flake graphite (mean chord length: 24.97 µm) after ultrasound treatment was limited due to the difficulty of generating sufficient fragmentation and dissociation by microjets and shock waves formed by the cavitation effect. Compared with conventional flotation, the concentrate yield of ultrasound flotation increased from 88.95 to 94.98%, ash content decreased from 5.72 to 4.87%, and ash removal rate enhanced from 36.94 to 42.61%. Particle size and mineral property analyses confirmed that further crushing and dissociation of the larger flake graphite after ultrasound pretreatment would be the main factors contributing to improved flotation performance. Additionally, the formation of air flocs in the coarse flake graphite during the ultrasound pretreatment process facilitated the flotation recovery of the crushed graphite particles.

Structurally diverse triterpenoid alkaloids from Buxus rugulosa.

Four new nortriterpenoid alkaloids, namely buxrugulines E-H (1-4), along with five known ones (5-9), were isolated from the twigs and leaves of Buxus rugulosa. Their structures were identified based on extensive NMR data and MS spectroscopic analyses. Our bioassays revealed that compounds 5, 6 and 8 exhibited potent cytotoxicity in vitro against MCF-7 cell lines, with IC50 values ranging from 6.70 to 11.00 µM, respectively.

Effects of wearing masks during COVID-19 pandemic on the composition and diversity of skin bacteria and fungi in medical workers.

Background: Although studies have shown that wearing masks can affect the skin microbiome, more detailed and comprehensive research on wearing masks needs to be further explored. Objective: This study aimed to characterize the influence of mask wearing on the diversity and structural characteristics of the facial skin microbial community of medical staff during the COVID-19 pandemic by means of metagenomic sequencing (mNGS). Methods: A total of 40 samples were taken by swabbing the cheek in the 2 × 2 cm2 area before and after wearing the masks. DNA was extracted for metagenomic sequencing. Results: A statistically significant decrease was found in the α diversity between BN and AN groups and between B2 h and A2 h groups. BN and AN mean groups before and after 8 h of wearing the medical protective mask (N95), including 10 volunteers, respectively. B2 h and A2 h mean groups before and after 8 h of wearing masks, including 10 volunteers changing mask every 2 h, respectively. The ß diversity was found to be statistically reduced between BS and AS groups (p = 0.025), BN and AN groups (p = 0.009), and B2 h and A2 h group (p = 0.042). The fungal beta diversity was significantly decreased in every group before and after wearing masks. The main bacteria on the face before and after wearing masks were Cutibacterium (68.02 and 71.73%). Among the fungi, Malassezia predominated the facial skin surface before and after wearing masks (35.81 and 39.63%, respectively). Conclusion: Wearing different types of masks and changing masks according to different frequency will have different effects on the facial skin's microbiota.

Physical activity's impact on rural older adult health: The multiple mediating effects of education, income, and psychological capital.

Introduction: This study aims to explore the influence mechanism of rural older adult health. By examining the mediating roles of education, income, and psychological capital in physical activity's impact on health, this study provides a reference for lifestyle interventions to improve the health level of rural older adults. Methods: The analysis was conducted on a sample of 1778 rural older adults from CGSS2017, and data were analyzed using PROCESS V4.2 for multiple mediating effects. Results: The findings indicate that physical activity impacts rural older adult health through multiple mediating pathways. The mediating role includes seven paths, comprising the independent effects of three mediating variables of income, education, and psychological capital, and the chain mediating effects generated together. Discussion: Based on the influence mechanism of health on rural older adults, optimizing policy focus and developing a precise, interconnected, and sustainable health security system for older adults is necessary. These research results are of practical significance for advancing healthy aging in rural areas.

Happiness and mental health of older adults: multiple mediation analysis.

Introduction: This study aims to explore the influence mechanism of older adult mental health. As the aging population grows, the mental health of older adults becomes a significant public health and social issue, with happiness serving as a key dimension of mental health. Methods: This study utilizes public data from CGSS to investigate the relationship between happiness and mental health, with Process V4.1 used for mediating effects analysis. Results: The findings suggest a positive predictive effect of happiness on mental health, with three mediating paths identified: independent mediating effect paths of income satisfaction and health, as well as a multiple mediating effects path through income satisfaction and health. Discussion: The study suggests that improving the multi-subject mental health support service system for older adults and creating public values for mental health risk coping mechanisms. This helps to understand the complex relationship between aging on individual and social levels. These results provide empirical support for healthy aging among older adults and future policymaking.

d-chiro-Inositol Derivatives with Multidrug Resistance Reversal Activities from the Fruits of Chisocheton siamensis.

Chisosiamols A-K (1-11), 11 new d-chiro-inositol derivatives, along with a known analogue (12) were isolated from the fruits of Chisocheton siamensis. Their planar structures and relative configurations were elucidated by the comprehensive application of spectroscopic methods, especially from the characteristic coupling constants, and 1H-1H COSY spectra. The absolute configurations of the d-chiro-inositol core were determined using the ECD exciton chirality and X-ray diffraction crystallographic analytical methods. This is the first crystallographic data reported for the d-chiro-inositol derivatives. A structural elucidation strategy mainly combining 1H-1H COSY correlations and ECD exciton chirality for determining the structure of d-chiro-inositol derivatives was developed, which also led to the revisions of previously reported structures. Bioactivity evaluation indicated that chisosiamols A, B, and J can reverse multidrug resistance in MCF-7/DOX cells in the IC50 range of 3.4-6.5 µM (RF: 3.6-7.0).

The Relationship Between College Students' Interpersonal Relationship and Mental Health: Multiple Mediating Effect of Safety Awareness and College Planning.

Purpose: The research intends to find the internal influence mechanism of interpersonal relationship on college students' mental health. College students have many mental health problems, which can easily lead to extreme events. It is of great research value to explore the relationship among interpersonal relationship, safety awareness, college planning, and mental health. Participants and Methods: GHQ, WHOQOL-BREF, SWBS-CC, LSIB, and TSCS scales were used, revised questionnaire for cluster sampling of college students, 1661 valid samples. SPSS 26.0 and PROCESS V4.1 were used for analysis, and nonparametric Bootstrap method was used to test the significance level of the mediating effect. Results: There are significant differences in interpersonal relationship, safety awareness, and college planning between high mental health group and low mental health group. There are differences in safety awareness between genders. There is a positive correlation among interpersonal relationship, safety awareness, college planning, and mental health. Interpersonal relationship has a positive predictive effect on mental health. There are three mediating pathways of interpersonal relationship on mental health: independent mediating effect pathway of safety awareness, independent mediating effect pathway of college planning, and chain mediating effect pathway through safety awareness and college planning. Conclusion: This study reveals the Influence mechanism of interpersonal relationships on college students' mental health. The relationship between interpersonal relationship and mental health is affected by the multiple mediating effects of safety awareness and college planning. It provides a new perspective for preventing and intervening mental health problems. College students' personality has plasticity, which can be interfered by mediating mechanism. The present findings could help college students actively participate in interpersonal communication, improve safety awareness, and make a good college planning, so as to enhance the mental health level of college students.

Current understanding on the role of CCT3 in cancer research.

Chaperonin containing TCP1 Subunit 3 (CCT3) is an important member of the chaperone protein family, providing a favorable environment for the correct folding of proteins in cell division, proliferation, and apoptosis pathways, which is involved in a variety of biological processes as well as the development and invasion of many malignant tumors. Many malignancies have been extensively examined with CCT3. It is presently used as a possible target for the treatment of many malignancies since it is not only a novel biomarker for the screening and diagnosis of different tumors, but it is also closely associated with tumor progression, prognosis, and survival. Recent studies have shown that the expression of CCT3 is up-regulated in some tumors, such as liver cancer, breast cancer, colon cancer, acute myeloid leukemia, etc. In this paper, we review the role of CCT3 in various tumors.

A/D-rings-seco limonoids from the fruits of Aglaia edulis and their bioactivities.

Agledulines A-K, eleven previously undescribed limonoids, including eight biogenic A/D-rings-seco limonoid analogs (agledulines A-H), one D-ring-seco limonoid (agleduline I) and two A-ring-seco limonoids with a rare Δ4,28 moiety (agledulines J-K), together with twelve reported limonoids, were isolated from the fruits of Aglaia edulis. Their structures were determined by NMR data, HRESIMS, X-ray diffraction, ECD spectra and the CD exciton chirality method. Observably, the absolute configurations of agleduline A, agleduline C and nymania 2 were unambiguously elucidated by single-crystal X-ray diffraction analyses. The biological evaluation showed that agleduline C exhibited significant cytotoxic activities with IC50 values of 10.05 µM, and 11α-acetoxygedunin showed notable anti-inflammatory activity (IC50: 4.70 µM). In addition, agleduline I and 11α-acetoxygedunin reversed the multidrug resistance with IC50 values of 5.05 and 1.49 µM (RI: 4.64 and 15.77) in the MCF-7/Dox cells.

Limonoids with Diverse Oxidation Patterns of C-12 Indicating a Complete Ring C-seco Biogenetic Pathway from Munronia unifoliolata.

Munrolins A-Q (1-17), 17 new ring C-seco limonoids with diverse oxidative patterns of C-12, together with nine known analogues (18-26), were isolated from the CH2Cl2 extract of Munronia unifoliolata. The planar structures were elucidated by a combination of 1D and 2D NMR and HR-MS analyses, while the absolute configurations were confirmed by ECD calculations and single-crystal X-ray diffraction. Munrolins A (1) and B (2) were first identified as ring C-seco limonoids with a 12,13-ether bridge moiety. Munrolins C-J (3-10) have a rare reduced primary alcohol fragment, while munrolin Q (17) has an unusual ketal fragment formed by dehydration of C-12/14. These limonoids with diverse alcohol and aldehyde type C11/12 branches may be generated through different degrees of reduction after the Baeyer-Villiger oxidation at the C ring, as key intermediates to supplement the biogenetic pathway of ring C-seco limonoids. Compounds 11, 19, and 26 could reverse the multidrug resistance of MCF-7/doxorubicin cells with reversal fold values of 5.2, 4.5, and 18.3, respectively.

Aglatestine A, a Rearranged Limonoid with a 3/6/6 Tricarbocyclic Framework from the Fruits of Aglaia edulis.

Aglatestine A (1), an unprecedented 3/6/6 tricarbocyclic limonoid framework along with four biogenic A/D-seco limonoid analogues with rare ß-substituents at C-6 (2-5), was discovered from the fruits of Aglaia edulis. The structures of 1-5 along with their absolute configurations were clarified using methods of HRMS(ESI), NMR, electronic circular dichroism, X-ray diffraction crystallography, and quantum chemical calculations. The plausible biogenetic speculation suggested that an electrophilic cyclization between C-1 carbocation from acetolysis and electron-rich C-5 from enolization of C═O of 2 may play a key role. The biological evaluation showed that 5 exhibited anti-inflammatory activity indicated by inhibiting NO release in LPS-activated RAW 264.7 macrophages (IC50: 35.72 ± 1.96 µM).

Topography-Dependent Effective Contact Line in Droplet Depinning.

The mobility of a fakir state droplet on a structured surface is fundamentally determined by the effective length of a microscopic contact line. However, it is largely unknown how the surface topography determines the effective contact line length. Based on the direct measurement of droplet adhesion force and the visualization of contact line, this work shows that effective contact line length is topography dependent as opposed to prior notion. On pored surfaces, contact line is not distorted, and the effective length approaches the droplet apparent perimeter regardless of pore dimensions. On pillared surfaces, the distortion of contact line is significantly dependent on the packing density of the pillar structures so that the effective length is as small as a pillar diameter on densely packed pillars and as large as a pillar perimeter on sparsely-packed pillars, while changing linearly between the two extremes.

The cohesin loader SCC2 contains a PHD finger that is required for meiosis in land plants.

Cohesin, a multisubunit protein complex, is required for holding sister chromatids together during mitosis and meiosis. The recruitment of cohesin by the sister chromatid cohesion 2/4 (SCC2/4) complex has been extensively studied in Saccharomyces cerevisiae mitosis, but its role in mitosis and meiosis remains poorly understood in multicellular organisms, because complete loss-of-function of either gene causes embryonic lethality. Here, we identified a weak allele of Atscc2 (Atscc2-5) that has only minor defects in vegetative development but exhibits a significant reduction in fertility. Cytological analyses of Atscc2-5 reveal multiple meiotic phenotypes including defects in chromosomal axis formation, meiosis-specific cohesin loading, homolog pairing and synapsis, and AtSPO11-1-dependent double strand break repair. Surprisingly, even though AtSCC2 interacts with AtSCC4 in vitro and in vivo, meiosis-specific knockdown of AtSCC4 expression does not cause any meiotic defect, suggesting that the SCC2-SCC4 complex has divergent roles in mitosis and meiosis. SCC2 homologs from land plants have a unique plant homeodomain (PHD) motif not found in other species. We show that the AtSCC2 PHD domain can bind to the N terminus of histones and is required for meiosis but not mitosis. Taken together, our results provide evidence that unlike SCC2 in other organisms, SCC2 requires a functional PHD domain during meiosis in land plants.

The in-plane crashworthiness of multi-layer regularly arranged circular honeycombs.

The in-plane crashworthiness of multi-layer regularly arranged circular honeycombs are investigated numerically at v = 1-250 m/s, with aim to disclose the influences of t/R ratio and crushing velocity, v. A novel evaluation methodology of crashworthiness and a new mechanical term, most appropriate strain, are put forward, which results in some new evaluation parameters. The theoretical analysis shows the most appropriate strain is a significant parameter for measuring the crashworthiness. Different deformation modes cause different change rules of these evaluation parameters. Under the quasi-static homogeneous mode and transition mode, the most appropriate strain is linear with the t/R ratio for a given v; the crushing force efficiency is approximately independent of t/R and sensitive to the v; the maximum energy absorption efficiency roughly decreases and then fluctuates. With the increase of v, the crushing force efficiency first becomes smaller sharply, and then fluctuates. Under dynamic mode, the maximum energy absorption efficiency is nearly constant for a given t/R ratio. Based on the finite element results, the empirical expressions of all evaluation parameters are given. The finite element calculated results of optimal specific energy absorption are consistent with those calculated by empirical expressions, which validates all empirical expressions.

Magnetic Resonance Imaging-Guided Drug Delivery to Breast Cancer Stem-Like Cells.

The feasibility of detecting breast cancer stem-like cells (BCSCs) with magnetic resonance imaging using extradomain-B of fibronectin (EDB-FN)-specific peptide (APTEDB )-conjugated thermally cross-linked superparamagnetic iron oxide nanoparticles (APTEDB -TCL-SPIONs) is previously demonstrated. Here, doxorubicin (Dox)-loaded APTEDB -TCL-SPIONs (Dox@APTEDB -TCL-SPIONs) are generated and their theranostic ability in a BCSC xenograft mouse model is assessed. The Dox@APTEDB -TCL-SPIONs enable more efficient delivery of Dox to tumors than nontargeted Dox@TCL-SPIONs. Much greater inhibition of BCSC tumor growth is observed after treatment with the Dox@APTEDB -TCL-SPIONs than with either Dox@TCL-SPIONs or free Dox. Hypointense signals are observed in the majority of the mice in postcontrast but not precontrast T2*-weighted MR images of tumors 7 days after treatment with Dox@APTEDB -TCL-SPIONs. An inverse correlation is observed between signal intensity and both EDB-FN expression and response to chemotherapy. The data indicate Dox@APTEDB -TCL-SPIONs can detect BCSCs within tumors by targeting EDB-FN-expressing cells. These nanoparticles thus have theranostic potential in breast cancer.

Spontaneous Spreading of a Droplet: The Role of Solid Continuity and Advancing Contact Angle.

Spontaneous spreading of a droplet on a solid surface is poorly understood from a macroscopic level down to a molecular level. Here, we investigate the effect of surface topography and wettability on spontaneous spreading of a water droplet. Spreading force is measured for a suspended droplet that minimizes interference of kinetic energy in the spontaneous spreading during its contact with solid surfaces of discontinuous (pillar) and continuous (pore) patterns with various shapes and dimensions. Results show that a droplet cannot spread spontaneously on pillared surfaces regardless of their shapes or dimensions because of the solid discontinuity. On the contrary, a droplet on pored surfaces can undergo spontaneous spreading whose force increases with a decrease in the advancing contact angle. Theoretical models based on both the system free energy and capillary force along the contact line validate the direct and universal dependency of the spontaneous spreading force on the advancing contact angle.

Downregulation of Choline Kinase-Alpha Enhances Autophagy in Tamoxifen-Resistant Breast Cancer Cells.

Choline kinase-α (Chk-α) and autophagy have gained much attention, as they relate to the drug-resistance of breast cancer. Here, we explored the potential connection between Chk-α and autophagy in the mechanisms driving to tamoxifen (TAM) resistance, in estrogen receptor positive (ER+) breast cancer cells (BCCs). Human BCC lines (MCF-7 and TAM-resistant MCF-7 (MCF-7/TAM) cells) were used. Chk-α expression and activity was suppressed by the transduction of shRNA (shChk-α) with lentivirus and treatment with CK37, a Chk-α inhibitor. MCF-7/TAM cells had higher Chk-α expression and phosphocholine levels than MCF-7 cells. A specific downregulation of Chk-α by the transduction of shChk-α exhibited a significant decrease in phosphocholine levels in MCF-7 and MCF-7/TAM cells. The autophagy-related protein, cleaved microtubule-associated protein light chain 3 (LC3) and autophagosome-like structures were significantly increased in shChk-α-transduced or CK37-treated MCF-7 and MCF-7/TAM cells. The downregulation of Chk-α attenuated the phosphorylation of AKT, ERK1/2, and mTOR in both MCF-7 and MCF-7/TAM cells. In MCF-7 cells, the downregulation of Chk-α resulted in an induction of autophagy, a decreased proliferation ability and an activation of caspase-3. In MCF-7/TAM cells, despite a significant decrease in proliferation ability and an increase in the percentage of cells in the G0/G1 phase of the cell cycle, the downregulation of Chk-α did not induced caspase-dependent cell death and further enhanced autophagy and G0/G1 phase arrest. An autophagy inhibitor, methyladenine (3-MA) induced death and attenuated the level of elevated LC3 in MCF-7/TAM cells. Elucidating the interplay between choline metabolism and autophagy will provide unique opportunities to identify new therapeutic targets and develop novel treatment strategies that preferentially target TAM-resistance.

Targeted Therapy for Breast Cancer Stem Cells by Liposomal Delivery of siRNA against Fibronectin EDB.

Targeted therapy for breast cancer stem cell (BCSC): A novel liposomal system (APTEDB -LS-siRNA(EDB) ) that enables simultaneous targeting and knockdown of extra domain B of fibronectin (EDB-FN) shows potent therapeutic efficacy in the BCSC-derived tumors in vivo.

MRI of breast tumor initiating cells using the extra domain-B of fibronectin targeting nanoparticles.

The identification of breast tumor initiating cells (BTICs) is important for the diagnosis and therapy of breast cancers. This study was undertaken to evaluate whether the extra domain-B of fibronectin (EDB-FN) could be used as a new biomarker for BTICs and whether EDB-FN targeting superparamagnetic iron oxide nanoparticles (SPIONs) could be used as a magnetic resonance imaging (MRI) contrast agent for BTIC imaging in vitro and in vivo. BTICs (NDY-1) exhibited high EDB-FN expression, whereas non-BTICs (MCF-7, BT-474, SUM-225, MDA-MB-231) did not exhibit EDB-FN expression. Furthermore, Cy3.3-labeled EDB-FN specific peptides (APTEDB) showed preferential binding to the targeted NDY-1 cells. To construct an EDB-FN targeted imaging probe, APTEDB was covalently attached to a thermally cross-linked SPION (TCL-SPION) to yield APTEDB-TCL-SPION. In the in vitro MRI of cell phantoms, selective binding of APTEDB-TCL-SPION to NDY-1 cells was evident, but little binding was observed in MCF-7 cells. After the intravenous injection of APTEDB-TCL-SPION into the NDY-1 mouse tumor xenograft model, a significant decrease in the signal within the tumor was observed in the T2*-weighted images; however, there was only a marginal change in the signal of non-targeting SPIONs such as APTscramble-TCL-SPION or TCL-SPION. Taken together, we report for the first time that EDB-FN was abundantly expressed in BTICs and may therefore be useful as a new biomarker for identifying BTICs. Our study also suggests that APTEDB-TCL-SPION could be used as an MRI contrast agent for BTIC imaging.

Deep genome-wide measurement of meiotic gene conversion using tetrad analysis in Arabidopsis thaliana.

Gene conversion, the non-reciprocal exchange of genetic information, is one of the potential products of meiotic recombination. It can shape genome structure by acting on repetitive DNA elements, influence allele frequencies at the population level, and is known to be implicated in human disease. But gene conversion is hard to detect directly except in organisms, like fungi, that group their gametes following meiosis. We have developed a novel visual assay that enables us to detect gene conversion events directly in the gametes of the flowering plant Arabidopsis thaliana. Using this assay we measured gene conversion events across the genome of more than one million meioses and determined that the genome-wide average frequency is 3.5×10(-4) conversions per locus per meiosis. We also detected significant locus-to-locus variation in conversion frequency but no intra-locus variation. Significantly, we found one locus on the short arm of chromosome 4 that experienced 3-fold to 6-fold more gene conversions than the other loci tested. Finally, we demonstrated that we could modulate conversion frequency by varying experimental conditions.