Dewatering behavior and regulation mechanism of montmorillonite nanosheet in aqueous solution.

Two-dimensional montmorillonite nanosheet (MMTNS) is desirable building block for fabricating multifunctional materials as due to its extraordinary properties. In practical applications, however, the concentration of MMTNS prepared by exfoliation is normally too low to be used for material assembling. The general thermal-concentration method is effective, however, it can be time-consuming and require a lot of energy. In this case, the remarkable dispersion stability of MMTNS is worth noting. Herein, the extraordinary dispersion stability of MMTNS derived from electrostatic and hydration repulsion was firstly revealed by molecular dynamics (MD) simulation, which caused the poor dewatering of MMTNS. Further, based on the surface and structural chemistry of MMTNS, a series of strategies, involving charge and cross-linked structure regulation on the edge surface, as well as electrical double-layer modulation and calcification modification based on the electrolytes, were proposed to inhibit the dispersion and enhance the aggregation of MMTNS. Intriguingly, a novel chemical, Tetraethylenepentamine (TEPA) was applied in the dewatering of MMTNS. The TEPA not only act as a cross-linker to bond with MMTNS into an easy-to-dewatering 3D network structure, but also act as a switch for effortless viscosity tuning. Meanwhile, the dual function of electrolytes for electrical double layer compression and calcification modification of MMTNS was investigated by DLVO theory and structural analyses. This work offers explicit directions for improving the dewatering performance of MMTNS to meet the requirements of practical implementation.

Graft-versus-host disease complicated with small bowel obstruction in children: A case report.

Graft-versus-host disease (GvHD) is a severe complication following hematopoietic cell transplantation (HCT). The clinical manifestations of GvHD can affect multiple systems. Although gastrointestinal (GI) GvHD is common, GI obstruction complications are rare. Here, we present a case of GI-GvHD after HCT for acute myeloid leukemia (AML) in a young girl from China. The patient suffered from watery diarrhea, which progressed to bloody diarrhea 40 days after HCT. She experienced prolonged and repeated mucous or bloody stool after the withdrawal of cyclosporine and the gradual reduction in methylprednisolone. The plain abdominal radiography and computed tomographic (CT) scan showed apparent bowel wall thickening and intestinal stenosis 10 months after HCT. Finally, the patient underwent surgery to remove the small intestinal stenosis at the age of 26 months. The patient recovered with the help of appropriate medical therapies and nutritional support during hospitalization. She remained stable, and there was no recurrence of GI symptoms 16 months after the surgery. In summary, surgery may be an optimal treatment for GvHD patients with persistent bowel obstruction and failure of appropriate immunosuppressive therapies.

Enhanced removal of fluoride from water through precise regulation of active aluminum phase using CaCO3.

Coagulation with aluminum salts is an important method for fluoride removal from groundwater. However, the hydration of aluminum salts generating a large number of H+ usually leads to limited defluorination performance due to the optimum pH of active aluminum phase for fluoride removal around 5.5-6.5. In this work, enhanced fluoride removal from groundwater through precise regulation of active aluminum phase by CaCO3 was investigated. Precipitation products were characterized by XPS, FTIR, XRD, and SEM, respectively, and the mechanism of the high fluoride removal efficiency was discussed and compared with the traditional coagulation of Al2(SO4)3. In the Al2(SO4)3 + CaCO3 (ASCC) system, CaCO3 can stably regulate the pH at the optimum range for active aluminum phase existence and has the best fluoride removal effect. CaCO3 accurately regulated the activity of the aluminum phase by slowly releasing OH- and fine tuning pH, thereby achieving effective fluoride removal. Undissolved CaCO3 particles exist as the carrier of defluorination flocs to accelerate precipitation and improve stability. The work here provides a new method for fluoride removal and may shed light on the application of CaCO3 coagulants for other pollutants.

Precise Cation Recognition in Two-Dimensional Nanofluidic Channels of Clay Membranes Imparted from Intrinsic Selectivity of Clays.

Various kinds of clays occur naturally and are accompanied by particular cations in their interlayer domains. Here we report the reassembled membranes with nanofluidic channel arrays by using the natural clays montmorillonite, mica, and vermiculite, which were imparted with the natural selectivity for realizing precise recognition and directional regulation of the naturally occurring interlayer cations. A typical surface-governed ionic transport behavior was observed in the clay nanofluidic channels. Through asymmetric structural modification, cationic current rectification was realized in montmorillonite channels that performed as a nanofluidic diode. Interestingly, in the mica nanofluidic channel, the K+ that was naturally occurring in the interlayer domain of mica showed a reciprocating motion and resulted in a periodically fluctuating current. Electrodialysis demonstrated that such a fluctuating current reflects a directional selectivity for K+, achieving at least a 6000 times permeation rate difference with Li+ ions. The specific selectivity for Li+/Mg2+ on vermiculite reached up to 856 times with similar cations by the current technique. As-obtained clay membranes possess application prospects in energy conversion, brine resource development, etc. Such a strategy can achieve the designed selectivity through systematic screening of the building blocks, thus imparting them with the inherent characteristics of natural clays, which provides an alternative solution to the present manufacture of selective membranes.

Enhanced removal of refractory humic- and fulvic-like organics from biotreated landfill leachate by ozonation in packed bubble columns.

Biotreated landfill leachate contains much refractory organics such as humic and fulvic acids, which can be degraded by O3. However, the low O3 mass transfer and high energy cost limit its wide application in landfill leachate treatment. Previous studies proved that packed bubble columns could enhance the O3 mass transfer and increase the synthetic humic acids wastewater degradation, but the performance of packed bubble columns in real wastewater treatment has not been investigated. Therefore, this study aims to evaluate the feasibility of application of packed bubble column in the real biotreated landfill leachates treatment and provide insights into the transformation of organic matters in leachates during ozonation. Packed bubble columns with lava rocks or metal pall rings (LBC or MBC) were applied and compared with a non-packed bubble column (BC). At an applied O3 dose of 8.35 mg/(Lwater sample min), the initial COD (400 mg/L) was only removed for 26% in BC and 32% in MBC while this was 46% in LBC, indicating LBC has the best performance. GC-MS analysis shows that raw biotreated leachate contains potential endocrine disruptors such as di(2-ethylhexyl) phthalate (DEHP). 61% of DEHP was removed in LBC and the least intermediate oxidation products from humic- and fulvic-like organics was detected in LBC. The highest O3 utilization efficiency (89%) and hydroxyl radical (OH) exposure rate (3.0 × 10-10 M s) were observed in LBC with lowest energy consumption (EEO) for COD removal of 18 kWh/m3. The enhanced ozonation efficiency in LBC and MBC was attributed to the improved O3 mass transfer. Besides, LBC had additional adsorptive and catalytic activity that promoted the decomposition of O3 to generate OH. This study demonstrates that a packed bubble column increases removal and decreases energy use when treating landfill leachate, thus promoting the application of ozonation.

Clinical and Molecular Characterizations of Papillary Thyroid Cancer in Children and Young Adults: A Multicenter Retrospective Study.

Background: Papillary thyroid carcinoma (PTC) is a rare malignancy in children and young adults (CAYA). It often presents with aggressive disease patterns and advanced stages, which are clinically distinct from those in adult patients. In this study, we sought to characterize and better understand the clinical variants of PTC in CAYA and explore the underlying mechanisms. Methods: CAYA patients (age ≤18 years) diagnosed with PTC between June 2006 and June 2018 were retrospectively recruited from five hospitals. Demographic information, pathological data, and follow-up status were recorded. Tumor samples obtained from 20 children (mean age 15.15 years) and 10 adults (mean age 38.80 years) underwent comprehensive whole transcriptome sequencing. Differentially expressed genes (DEGs), mutational landscape, and immune infiltration were analyzed. Results: A total of 217 CAYA-PTC patients (162 females and 55 males) with an average age of 14.38 ± 3.53 years (range 2-18) were included. Lymph node metastasis (LNM) was observed in 85.71%, of which 57.60% were in the lateral cervical compartment. Disease recurred in 28 of 217 (12.90%) patients with a median follow-up of 4.76 years. Multivariate logistic regression analysis revealed that age, bilateral disease, extrathyroidal extension, and coexisting Hashimoto's thyroiditis (co-HT) were independent risk factors for LNM, while co-HT was the only risk factor for recurrence. Using whole transcriptome sequencing of PTC tissues, we identified 301 DEGs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that differences in immune mediators played important roles, based on the distributions of mutation frequencies, types, and expression levels between CAYA and adult patients. Based on the integrated data sets, we identified significantly mutated immune genes, cluster of differentiation 24 (CD24), coagulation factor 12 (F12), coagulation factor 5 (F5), integrin subunit alpha 3 (ITGA3), and retinoic acid early transcript 1L (RAET1L), which were then verified by immunohistochemistry. Furthermore, resting mast cells, resting natural killer cells, plasma cells, and regulatory T cells were different in the CAYA-PTC group and correlated with the expression of immune checkpoints. Conclusions: There are considerable variabilities that may contribute to the different clinical presentations between CAYA and adult PTC patients, among which the decrease in protective immune cells may be a factor. Collectively, our results add to the possible biological mechanisms involved in CAYA-PTC.

Synthesis of carboxymethyl cellulose-chitosan-montmorillonite nanosheets composite hydrogel for dye effluent remediation.

MMTNS were introduced into carboxymethyl cellulose-chitosan system to synthesize porous hydrogel adsorbent with stable structure and high dye handling capacity. Al-OH on edge of MMTNS formed hydrogen-bond (-OH···+NH3-) with -NH2 on CS, CS then cooperated with CMC via amidation and chains interleaving, forming three-dimensional hydrogel. Morphology characterization revealed that hydrogel possessed microporous open-framework structure, facilitating free entrance of macromolecular MB dye to react with internal reaction sites in hydrogel. Factor tests indicated that high removal (97%) of MB was achieved via 0.2 g/L hydrogel within 360 min even after 5 adsorption-regeneration cycles. Adsorption process followed Pseudo-first-order, Pseudo-second-order kinetic model and Sips isotherm model, owing to both monolayer physical and chemical adsorption behavior of MB molecules onto homogeneous surface of hydrogel. Adsorption mechanism was attributed to ion-exchange, groups combination of carboxyl and hydroxyl, and Si active sites reaction. Such hydrogel realized promotion of polysaccharide polymers in materials design and wastewater treatment.

Role of Montmorillonite, Kaolinite, or Illite in Pyrite Flotation: Differences in Clay Behavior Based on Their Structures.

It is widely acknowledged that clay minerals have detrimental effects on the process of flotation, but the mechanisms involved are still not fully understood. In this work, the effects of montmorillonite, kaolinite, and illite on pyrite flotation were investigated from the perspective of various structures of clay minerals. Flotation tests suggested that the detrimental effect of clay minerals on the flotation of pyrite increased as follows: montmorillonite > kaolinite > illite. With the help of rheology measurements, it was found that montmorillonite significantly increased pulp viscosity, which in turn substantially reduced pyrite recovery and grade. Scanning electron microscopy (SEM) images suggested that montmorillonite formed the "house-of-cards" structure by edge-to-edge and edge-to-face contact, while kaolinite and illite platelets were associated mainly in the face-to-face mode. In addition, it was clearly observed by SEM-energy dispersive spectrometry that montmorillonite and kaolinite coat on the pyrite surfaces, which would lower the surface hydrophobicity of pyrite. Kaolinite covered much larger area of pyrite surface than montmorillonite owing to the positive charge occurring at the exposed aluminum-oxygen octahedral sheet of kaolinite. Although illite has a similar 2:1 structure to montmorillonite, it showed little or no effect on pyrite flotation, which was attributed to its poor swelling nature. These findings shed light on the root cause of the adverse effect of clay minerals on pyrite flotation and are expected to provide theoretical guidance for mitigating the negative effects on flotation caused by clays.

Can Free Carnitine or Bilirubin in Blood Be Used in Neonatal Screening for Biliary Atresia?

OBJECTIVE: To investigate the efficiency of free carnitine, unconjugated bilirubin (UBIL), bilirubin monoglucuronide (BMG), and bilirubin diglucuronide (BDG) in dry blood spots (DBSs) measured using tandem mass spectrometry (MS/MS) for screening biliary atresia (BA). MATERIALS AND METHODS: All the patients with BA, residing in Shanghai, were collected from four different children's hospitals in Shanghai from January 1, 2015, to June 30, 2017. UBILMS, BMG, BDG, and free carnitine were measured in the DBS samples of 48 patients with BA, 10,008 pediatric patients, and 52,862 newborns using MS/MS. Conjugated bilirubin was measured by MS/MS (CBMS) = BMG + BDG, and total bilirubin was measured by MS/MS (TBMS) = UBILMS + CBMS. Four hundred pediatric patients' direct bilirubin (DB) and total bilirubin (TB), measured by the clinical laboratory and MS/MS, were used as a control. RESULTS: The total number of births at the registered permanent residences in Shanghai was 233,000; among them, the occurrence of BA was in 33 patients in 2 years. Therefore, the incidence of BA in Shanghai was 1:7,060. The ratio of DB/TB and CBMS/TBMS of most patients with BA was elevated gradually in the neonatal period and higher than the normal range after 1 month after birth. The area under the receiver operating characteristic curve of DB, DB/TB, CBMS/TBMS, CBMS, and free carnitine for predicting BA was 0.98, 0.95, 0.73, 0.57, and 0.92, respectively. Using the 95% percentile as a cutoff, the sensitivity of DB and free carnitine to predict BA was 100 and 85%, respectively, and the specificity was 52 and 85%, respectively. CONCLUSION: In free carnitine, DB, and CBMS/TBMS tests, blood concentrations are elevated in all infants with BA. However, they may not be elevated while they are newborns. These tests will result in high false negatives or positives. Thus, they should not be used as newborn screening tests for BA due to their lower sensitivity and specificity.