The monomer concentration is a key factor affecting the diffusion rate and reaction rate of the monomers and determines the physicochemical property of polyamide nanofiltration membranes. However, ...the mechanism of the monomer concentration effect on the polyamide nanofiltration membrane remains unclear. The properties of nascent membranes fabricated with different monomer concentrations with a fixed ratio presented completely new results in the absence of heat treatment. The results reveal that the polyamide layer thickness increases linearly with the monomer concentration when the concentration is high. The nanofiltration membranes prepared at a low concentration have a larger pore size and a lower cross-linking degree, which contributed to high water permeability. The optimal membrane presented a high pure water permeability of 36.1 L h–1 m–2 bar–1, with the Na2SO4 rejection maintained at 98.4%. This work provides a novel insight into the relationship between the properties of the nanofiltration membrane and monomer concentration.
Eight new sulfur-bridged pyranonaphthoquinone (PNQ) dimers, naquihexcins C–J (1–8), a new PNQ monomer, naquihexcin K (10), and three known analogues (9, 11, and 12) were isolated from Streptomyces ...sp. KIB3133. The new structures were elucidated by interpretation of spectroscopic data. Dimer 4 was synthesized via a cascade SN2 reactions between two monomers and sodium sulfide, an approach motivated by the proposed biosynthetic pathway of dimeric pyranonaphthoquinones. Naquihexcin E (3) exhibited moderate HIV-1 inhibitory activity. Naquihexcins C (1), E (3), and I (7) showed inhibitory effects against two tumor cell lines (HL-60 and MCF-7) with IC50 values ranging from 1.4 to 16.1 μM.
Ethylene/α-olefin copolymers are produced in huge scale and widely used, but their after-use disposal has caused plastic pollution problems. Their chemical inertness made chemical re/upcycling ...difficult. Ideally, PE materials should be made de novo to have a circular closed-loop lifecycle. However, synthesis of circular ethylene/α-olefin copolymers, including high-volume, linear low-density PE as well as high-value olefin elastomers and block copolymers, presents a particular challenge due to difficulties in introducing branches while simultaneously installing chemical recyclability and directly using industrial ethylene and α-olefin feedstocks. Here we show that coupling of industrial coordination copolymerization of ethylene and α-olefins with a designed functionalized chain-transfer agent, followed by modular assembly of the resulting AB telechelic polyolefin building blocks by polycondensation, affords a series of ester-linked PE-based copolymers. These new materials not only retain thermomechanical properties of PE-based materials but also exhibit full chemical circularity via simple transesterification and markedly enhanced adhesion to polar surfaces.
Introduction
TET2, a member of the Ten‐Eleven translocation gene family, catalyzes the conversion of 5‐methylcytosine to 5‐hydroxymethylcytosine in DNA. Low expression of TET2 has been reported as a ...prognostic factor for several types of malignancies in adult patients. However, there have been few data on the effect of TET2 mRNA level on the prognosis of children with ALL so far.
Methods
In this study, TET2 expression of samples cryopreserved in the liquid nitrogen from January 1, 2007 through December 31, 2011 was retrospectively analyzed in 136 newly diagnosed ALL patients by real‐time polymerase chain reaction (PCR) assay. The patients' samples were divided into two groups by the median value of patients group and divided into TET2 low and TET2 high groups.
Results
A total of 136 childhood ALL patients demonstrated lower TET2 expression than control group (P = .038). TET2 mRNA expression levels were correlated with the disease status. In addition, patients with low TET2 expression had lower platelet counts and lower CR rates. Survival analysis showed that low TET2 expression in children with ALL was associated with lower 5‐year overall survival (OS) (63% vs 88%, P = .011) and event‐free survival (EFS) (60% vs 85%, P = .003). Multivariate analysis revealed that low TET2 expression was an independent poor prognostic factor of OS and EFS.
Conclusion
Low expression of TET2 in children with ALL is associated with poor prognosis and can be used as a molecular prognostic marker for risk group stratification.
The electromagnetic brake (EMBr) is a well-known and widely applied technology for controlling the melt flow in the continuous casting (CC) of the steel. The effect of a steady (DC) magnetic field ...(0.31 T) in a CC mold is numerically studied based on the GaInSn experiment. The electrical boundary conditions are varied by considering a perfectly insulating/conductive mold or the presence of a conductive solid shell, which is experimentally modeled by 0.5 mm brass plates. An intense current density (up to 350 kA/m
2
) is induced by the EMBr magnetic field in the form of loops. The electric current loop tends to close either inside the liquid bulk or through the conductive solid. Based on the character of the induced current loop closures, the turbulent flow is affected as follows: (i) it becomes unstable in the insulated mold, forming 2D self-inducing vortex structures aligned with the magnetic field; (ii) it is strongly damped for the conductive mold; and (iii) it exhibits transitional behavior with the presence of a solid shell. The application of the obtained results for the real CC process is discussed and validated.
Zinc is an essential nutrient for life, but over-accumulation can result in toxicity. Anthropogenic activities can increase zinc concentrations in aquatic environments (e.g., to ∼0.46–1.00 mg/L), ...which are above the safe level of 0.1 mg/L. We investigated the behavior and physiology of zebrafish (Danio rerio) in response to environment-related exposure to zinc chloride at 0.0 (Ctrl), 1.0 (ZnCl2-low) and 1.5 (ZnCl2-high) mg/L for 6 weeks (the zinc conversion ratio of zinc chloride is ∼0.48 and the nominal (measured) values were: Ctrl, 0 (∼0.01); ZnCl2-low, 0.48 (∼0.51); ZnCl2-high, 0.72 (∼0.69) mg/L). Low-zinc exposure resulted in significantly increased locomotion and fast moving behaviors, while high-zinc exposure resulted in significantly increased aggression and freezing frequency. Single cell RNA-seq of neurons, astrocytes, and oligodendrocytes of the brain revealed expression of genes related to ion transport, neuron generation, and immunomodulation that were heterogeneously regulated by zinc exposure. Astrocyte-induced central nervous system inflammation potentially integrated neurotoxicity and behavior. Integrated analyses of brain and hepatic transcriptional signatures showed that genes (and pathways) dysregulated by zinc were associated with sensory functions, circadian rhythm, glucose and lipid metabolism, and amyloid β-protein clearance. Our results showed that environment-related zinc contamination can be heterogeneously toxic to brain cells and can disturb coordination of brain-liver physiology. This may disrupt neurobehavior and cause a neurodegeneration-like syndrome in adult zebrafish.
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•Zinc exposure altered zebrafish neurobehavioral phenotypes.•Zinc exhibited heterogeneously toxic to brain cells.•Zinc exposure resulted in astrocyte-induced CNS inflammation.•Zinc exposure dysregulated brain-liver circadian and metabolism coordination.
•The IMN-2 and IMN-3 with intermediate channel width yield higher htp at moderate to high heat fluxes.•The pressure drop declines distinctly with the increment of channel width.•The IMN-2 with the ...channel width of 0.4mm significantly suppresses the two-phase instability.•The htp changes in line with the flow pattern transition from nucleate to convective boiling.
Developed thermal management solutions for microelectronic fields have got extensive attentions these years. In this study, an interconnected microchannel net (IMN) was developed via micro wire electrical discharge machining process to explore the feasibility of flow boiling heat transfer enhancement. The experiments for the IMNs with different structural parameters were conducted using deionized water as the coolant with variation in the heat flux and under an inlet subcooling of 40°C and constant mass flow rate of 180kgm−2s−1. Four IMN samples with different channel width, i.e., 0.25, 0.4, 0.55 and 0.7mm, were investigated to study the effects of channel size and heat flux on flow boiling characteristics, i.e., two-phase heat transfer, pressure drops and two-phase flow instabilities, were proceeded in order to optimize the structural design of the IMN. Test results indicate that the sample IMN-2 with the channel width of 0.4mm manifests the overall best flow boiling performance, which exhibits more favorable two-phase heat transfer and pressure drop characteristics, as well as the prominent superiority for the mitigation of two-phase instability. This reveals a highlight for the potential application in the flow boiling enhancement of microchannel heat transfer.
Statins have been demonstrated to effectively inhibit proliferation and induce apoptosis in cancer cells by inhibition of geranylgeranylation, however its novel molecular mechanism remains to be ...determined. Recently simvastatin has been found to result in the synergistic induction of apoptosis with 7-hydroxystaurosporine (UCN-01) (a Chk1 inhibitor) in myeloma cells. Therefore we hypothesized that Chk1 plays a role in the anti-myeloma effect of simvastatin. Interestingly, we found that simvastatin caused a dose-dependent increase in S phase cell cycle and induced significant apoptosis. The results of western blot showed that simvastatin-induced S-phase cell cycle arrest was associated with activation of Chk1, downregulation of Cdc25A, cyclin A and CDK2 expression. Additionally, simvastatin-induced apoptosis was accompanied by diminished Bcl-2 protein expression, increased cytosolic cytochrome c level, and activation of caspase 9 and caspase 3. Further investigation revealed that silence of Chk1 expression by Chk1 specific siRNA inhibited simvastatin-induced activation of Chk1, downregulation of Cdc25A, cyclin A and CDK2 expression, and diminished S phase cell cycle arrest. Additionally, inhibition of Chk1 expression enhanced simvastatin-induced downregulation of Bcl-2, caspase 9 cleavage and subsequent apoptosis. These results suggested that the Chk1–Cdc25A–cyclin A/CDk2 pathway was involved in simvastatin-induced S-phase cell cycle arrest and apoptosis in multiple myeloma cell lines.
•Permian Oil in Xinguang bulge was mainly from Permian P1f source rock.•Permian oil in the Chepaizi area was mostly from Permian P2w source rock.•Xinguang Permian oils have higher thermal maturation ...than those from Chepaizi.•Two main petroleum chargings were recorded by fluid inclusion and fluorescence.•Laumontite has a considerable effect on the reservoir properties.
The Chepaizi–Xinguang area is a petroliferous region in the western Junggar basin that contains several Permian tight reservoirs and has a complex petroleum system and accumulation mechanism. The oil sources and accumulation mechanisms are investigated by an integrated analysis of biomarker assemblages in reservoir oil samples, microscopic analysis of rock samples, study of fluid inclusions, and simulation of the thermal evolution. The results show that the Permian oil in the Xinguang bulge is mainly generated from the Permian Fengcheng Formation with tricyclic terpane ratios C19 TT/C23 TT lower than 0.15, C23 TT/C21 TT higher than 1.0 and gammacerane/αβ C30 hopane higher than 0.6. The Permian oil in the Chepaizi area is mostly derived from Permian Wuerhe Formation with C19 TT/C23 TT higher than 0.15, C23 TT/C21 TT lower than 1.0 and gammacerane/αβ C30 hopane lower than 0.4. The Permian oils from the Xinguang bulge show higher maturity compared to the Permian oils from the Chepaizi area possibly as a result of later oil filling. The fluid inclusions and fluorescence record the main oil charging movements during the Late Triassic to Early Jurassic and the Late Jurassic to Early Cretaceous in this area, and most of the generated oils in late Permian are lost. The unconformities between Permian strata show higher porosity and more oil and gas enrichment comparatively and are the main pathways for lateral oil migration. Laumontite has had a considerable effect on reservoir properties. Laumontite dissolution creates pores that provide good oil reservoir space and favorable exploration targets.
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