Low Pneumoperitoneum Pressure Reduces Gas Embolism During Laparoscopic Liver Resection: A Randomized Controlled Trial.

OBJECTIVE: To compare the effect of low and standard pneumoperitoneal pressure (PP) on the occurrence of gas embolism during laparoscopic liver resection (LLR). BACKGROUND: LLR has an increased risk of gas embolism. Although animal studies have shown that low PP reduces the occurrence of gas embolism, clinical evidence is lacking. METHODS: This parallel, dual-arm, double-blind, randomized controlled trial included 141 patients undergoing elective LLR. Patients were randomized into standard ("S," 15 mm Hg; n = 70) or low ("L," 10 mm Hg; n = 71) PP groups. Severe gas embolism (≥ grade 3, based on the Schmandra microbubble method) was detected using transesophageal echocardiography and recorded as the primary outcome. Intraoperative vital signs and postoperative recovery profiles were also evaluated. RESULTS: Fewer severe gas embolism cases (n = 29, 40.8% vs n = 47, 67.1%, P = 0.003), fewer abrupt decreases in end-tidal carbon dioxide partial pressure, shorter severe gas embolism duration, less peripheral oxygen saturation reduction, and fewer increases in heart rate and lactate during gas embolization episodes was found in group L than in group S. Moreover, a higher arterial partial pressure of oxygen and peripheral oxygen saturation were observed, and fewer fluids and vasoactive drugs were administered in group L than in group S. In both groups, the distensibility index of the inferior vena cava negatively correlated with central venous pressure throughout LLR, and a comparable quality of recovery was observed. CONCLUSIONS: Low PP reduced the incidence and duration of severe gas embolism and achieved steadier hemodynamics and vital signs during LLR. Therefore, a low PP strategy can be considered a valuable choice for the future LLR.

Quantifying differences in plant architectural development between hybrid potato (Solanum tuberosum) plants grown from two types of propagules.

BACKGROUND AND AIMS: Plants can propagate generatively and vegetatively. The type of propagation and the resulting propagule can influence the growth of the plants, such as plant architectural development and pattern of biomass allocation. Potato is a species that can reproduce through both types of propagation: through true botanical seeds and seed tubers. The consequences of propagule type on the plant architectural development and biomass partitioning in potatoes are not well known. We quantified architectural differences between plants grown from these two types of propagules from the same genotype, explicitly analysing branching dynamics above and below ground, and related these differences to biomass allocation patterns. METHODS: A greenhouse experiment was conducted, using potato plants of the same genotype but grown from two types of propagules: true seeds and seed tubers from a plant grown from true seed (seedling tuber). Architectural traits and biomass allocation to different organs were quantified at four developmental stages. Differences between true-seed-grown and seedling-tuber-grown plants were compared at the whole-plant level and at the level of individual stems and branches, including their number, size and location on the plant. KEY RESULTS: A more branched and compact architecture was produced in true-seed-grown plants compared with seedling-tuber-grown plants. The architectural differences between plants grown from true seeds and seedling tubers appeared gradually and were attributed mainly to the divergent temporal-spatial distribution of lateral branches above and below ground on the main axis. The continual production of branches in true-seed-grown plants indicated their indeterminate growth habit, which was also reflected in a slower shift of biomass allocation from above- to below-ground branches, whereas the opposite trend was found in seedling-tuber-grown plants. CONCLUSIONS: In true-seed-grown plants, lateral branching was stronger and determined whole-plant architecture and plant function with regard to light interception and biomass production, compared with seedling-tuber-grown plants. This different role of branching indicates that a difference in preference between clonal and sexual reproduction might exist. The divergent branching behaviours in true-seed-grown and seedling-tuber-grown plants might be regulated by the different intensity of apical dominance, which suggests that the control of branching can depend on the propagule type.

Long Noncoding RNA HOTAIRM1 Promotes Immunosuppression in Sepsis by Inducing T Cell Exhaustion.

Sepsis is an acute life-threatening disorder associated with multiorgan dysfunction that remains the leading cause of death in intensive care units. As sepsis progresses, it causes prolonged immunosuppression, which results in sustained mortality, morbidity, and susceptibility to secondary infections. Using a mouse model of sepsis, we found that the long noncoding RNA HOTAIRM1 (HOXA transcript antisense RNA myeloid-specific 1) was highly expressed in mice during the late phase of sepsis. The upregulation of HOTAIRM1 was induced by Notch/Hes1 activation and, moreover, was critical for the formation of an immunosuppressive microenvironment. HOTAIRM1 induced T cell exhaustion by increasing the percentage of PD-1+ T cells and regulatory T cells, accompanied by elevated PD-L1. Blockade of either Notch/Hes1 signaling or HOTAIRM1 inhibited T cell exhaustion in late sepsis, having alleviated lung injury and improved survival of mice. Further mechanistic studies identified HOXA1 as a key transcription factor targeted by HOTAIRM1 to regulate PD-L1 expression in lung alveolar epithelial cells. These results implicated that the Notch/Hes1/HOTAIRM1/HOXA1/PD-L1 axis was critical for sepsis-induced immunosuppression and could be a potential target for sepsis therapies.

HSK3486 Inhibits Colorectal Cancer Growth by Promoting Oxidative Stress and ATPase Inhibitory Factor 1 Activation.

BACKGROUND: HSK3486 (ciprofol), a new candidate drug similar to propofol, exerts sedative and hypnotic effects through gamma-aminobutyric acid type A receptors; however, its potential role in colorectal cancer is currently unknown. AIMS: This study aimed to evaluate the effects of HSK3486 on colorectal cancer cell proliferation. METHODS: Imaging was performed to detect reactive oxygen species and mitochondrial membrane potential. Western blotting was used to determine the expression of target signals. The HSK3486 molecular mechanism was investigated through ATPase inhibitory factor 1 knockdown and xenograft model experiments to assess mitochondrial function in colorectal cancer cells. RESULTS: Cell Counting Kit-8 and Annexin V/propidium iodide double staining assays showed that HSK3486 inhibited colorectal cancer cell proliferation in a concentration-dependent manner. In addition, HSK3486 treatment increased the expression of B-cell lymphoma-2-associated X, cleaved caspase 3, and cleaved poly (ADP-ribose) polymerase, whereas myeloid cell leukemia-1 and B-cell lymphoma 2 expression decreased. HSK3486 promoted mitochondrial dysfunction by inducing ATPase inhibitor factor 1 expression. Furthermore, HSK3486 promoted oxidative stress, as shown by the increase in reactive oxygen species and lactate dehydrogenase levels, along with a decrease in mitochondrial membrane potential and ATP levels. ATPase inhibitor factor 1 small interfering RNA pretreatment dramatically increased the mitochondrial membrane potential and tumor size in a xenograft model following exposure to HSK3486. CONCLUSION: Collectively, our findings revealed that HSK3486 induces oxidative stress, resulting in colorectal cancer cell apoptosis, making it a potential candidate therapeutic strategy for colorectal cancer.

Prominent Size Effects without a Depolarization Field Observed in Ultrathin Ferroelectric Oxide Membranes.

The increasing miniaturization of electronics requires a better understanding of material properties at the nanoscale. Many studies have shown that there is a ferroelectric size limit in oxides, below which the ferroelectricity will be strongly suppressed due to the depolarization field, and whether such a limit still exists in the absence of the depolarization field remains unclear. Here, by applying uniaxial strain, we obtain pure in-plane polarized ferroelectricity in ultrathin SrTiO_{3} membranes, providing a clean system with high tunability to explore ferroelectric size effects especially the thickness-dependent ferroelectric instability with no depolarization field. Surprisingly, the domain size, ferroelectric transition temperature, and critical strain for room-temperature ferroelectricity all exhibit significant thickness dependence. These results indicate that the stability of ferroelectricity is suppressed (enhanced) by increasing the surface or bulk ratio (strain), which can be explained by considering the thickness-dependent dipole-dipole interactions within the transverse Ising model. Our study provides new insights into ferroelectric size effects and sheds light on the applications of ferroelectric thin films in nanoelectronics.

Relaxed 3D genome conformation facilitates the pluripotent to totipotent-like state transition in embryonic stem cells.

The 3D genome organization is crucial for gene regulation. Although recent studies have revealed a uniquely relaxed genome conformation in totipotent early blastomeres of both fertilized and cloned embryos, how weakened higher-order chromatin structure is functionally linked to totipotency acquisition remains elusive. Using low-input Hi-C, ATAC-seq and ChIP-seq, we systematically examined the dynamics of 3D genome and epigenome during pluripotent to totipotent-like state transition in mouse embryonic stem cells (ESCs). The spontaneously converted 2-cell-embryo-like cells (2CLCs) exhibited more relaxed chromatin architecture compared to ESCs, including global weakening of both enhancer-promoter interactions and TAD insulation. While the former correlated with inactivation of ESC enhancers and down-regulation of pluripotent genes, the latter might facilitate contacts between the putative new enhancers arising in 2CLCs and neighboring 2C genes. Importantly, disruption of chromatin organization by depleting CTCF or the cohesin complex promoted the ESC to 2CLC transition. Our results thus establish a critical role of 3D genome organization in totipotency acquisition.

Celastrol assuages oxygen-glucose deprivation and reoxygenation-induced damage in human brain microvascular endothelial cells through the circDLGAP4/miR-6085/GDF11 pathway.

The effect of Celastrol on cerebral ischemia-reperfusion remains unknown. The study aims to explore the role of circular RNA DLGAP4 (circDLGAP4) in cerebral ischemia-reperfusion and the underlying mechanism. Ischemia-reperfusion (I/R) injury of human brain microvascular endothelial cells (HBMECs) was induced by oxygen-glucose deprivation and reoxygenation (OGD/R). Reverse transcription quantitative real-time PCR (RT-qPCR) and western blotting analysis were performed to detect the expression of circDLGAP4, microRNA-6085 (miR-6085), growth differentiation factor 11 (GDF11), B-cell lymphoma-2 (BCL2) and BCL2-associated x protein (BAX). Cell viability, proliferation, and apoptosis were analyzed by cell counting kit-8, 5-Ethynyl-2'-deoxyuridine and flow cytometry analysis. Oxidative stress was analyzed by evaluating the levels of Malondialdehyde (MDA) and Reactive Oxygen Species (ROS) and the activity of Superoxide Dismutase (SOD). The associations among circDLGAP4, miR-6085 and GDF11 were identified by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. Celastrol reduced OGD/R-induced inhibition of circDLGAP4 expression in HBMECs. Celastrol treatment protected HBMECs from OGD/R-induced cell proliferation inhibition and apoptosis and oxidative stress promotion; however, circDLGAP4 depletion attenuated these effects. CircDLGAP4 acted as a sponge for miR-6085, and miR-6085 mimics restored circDLGAP4-mediated effects in OGD/R-stimulated HBMECs. In addition, GDF11 was identified as a targte of miR-6085, and participated in the regulation of miR-6085 to OGD/R-induced HBMEC damage. Further, circDLGAP4 absence inhibited GDF11 expression by interacting with miR-6085 under Celastrol treatment. Celastrol ameliorated OGD/R-induced HBMEC apoptosis and oxidative stress by circDLGAP4/miR-6085/GDF11 pathway, supporting the use of Celastrol as a therapeutic agent for cerebral infarction.

Intraoperative lidocaine infusion in patients undergoing pancreatectomy for pancreatic cancer: a mechanistic, multicentre randomised clinical trial.

BACKGROUND: Intravenous lidocaine has been postulated to improve long-term survival after surgery for pancreatic cancer through anti-inflammatory effects, anti-tumour effects, or both. We investigated whether intraoperative lidocaine improves survival after pancreatectomy for pancreatic cancer and whether lidocaine modified the formation of neutrophil extracellular traps (NETs), high levels of which are associated with poor prognosis. METHODS: Patients undergoing pancreatectomy were randomly assigned to i.v. lidocaine (continuous intraoperative infusion of 2 mg kg-1 h-1, after 1.5 mg kg-1 bolus at induction of anaesthesia) or saline placebo. The co-primary outcomes were survival/disease-free survival 3 yr after surgery. Secondary outcomes (masked to treatment allocation) included intraoperative opioid (sufentanil) dose, postoperative complications, and circulating and tumour-associated NETs (immunofluorescence assay, enzyme-linked immune assay, or both). RESULTS: A total of 563 participants (34.6% female; median age, 64 yr) completed 3 yr of clinical follow-up. Overall, 283 participants were randomised to lidocaine infusion, and 280 participants were randomised to placebo. Infusion of lidocaine did not alter overall (hazard ratio [HR]=0.98; 95% confidence interval [CI], 0.81-1.17; P=0.79) or disease-free survival (HR=0.91; 95% CI, 0.71-1.17; P=0.44). Mean intraoperative sufentanil dose was reduced by lidocaine infusion (47.6 µg [4.6]) compared with placebo (68.4 µg [4.8]; P<0.001), but postoperative complications and length of hospital stay were similar between groups. Circulating NETs were lower after lidocaine infusion up to 3 days after surgery, but tumour-associated NETs were not altered by intraoperative treatment. CONCLUSION: In patients undergoing pancreatectomy for pancreatic cancer, intraoperative infusion of lidocaine did not improve overall or disease-free survival. Reduced formation of circulating NETs was absent in pancreatic tumour tissue. CLINICAL TRIAL REGISTRATION: NCT03245346; updated in Chi-CTR-2000035469.

NBPF4 mitigates progression in colorectal cancer through the regulation of EZH2-associated ETFA.

Colorectal cancer (CRC) is one of the leading causes of death worldwide, and hence, there is a need to elucidate the molecular mechanisms contributing to the progression of CRC. In this study, we aimed at assessing the role of long non-coding RNA NBPF4 on the tumorigenesis of CRC. Silencing or overexpression experiments were performed on HCT116 and SW260 in vitro models. BALB/c athymic female nude mice aged 5-6 weeks were used as in vivo models. To assess the relationship between NBPF4 and its regulatory RNA pull-down assay, RNA immunoprecipitation, luciferase activity, Western blotting and qRT-PCR were employed. Initially, we identified that NBPF4 was downregulated in CRC tissues and cell lines. Furthermore, we observed that NBPF4 decreased tumorigenesis in both in vitro and in vivo models. Additionally, we identified that ETFA was highly expressed in CRCs and was negatively associated with NBPF4. Subsequently, we identified that EZH2, a transcriptional factor, activated ETFA by enhancing the methylation of its promoter, and EZH2 was also highly regulated in CRCs. Using COAD and READ databases, we confirmed that EZH2 and ETFA were positively correlated. Furthermore, we identified NBPF4 and EZH2 were targets for ZFP36, which bound and positively regulated NBPF4. This prevented NBPF4 from binding to its negative regulator miR-17-3p. Our results demonstrated that NBPF4 downregulated EZH2 and stabilized itself by binding to ZFP36, thus escaping from inhibition by miR-17-3p, which allowed mitigation of CRC through inhibition of ETFA.

ets1 associates with KMT5A to participate in high glucose-mediated EndMT via upregulation of PFN2 expression in diabetic nephropathy.

BACKGROUND: Diabetic nephropathy (DN) is currently the leading cause of end-stage renal disease globally. The endothelial-to-mesenchymal transition (EndMT) of glomerular endothelial cells has been reported to play a crucial role in DN. As a specific form of epithelial-to-mesenchymal transition, EndMT and epithelial-to-mesenchymal transition may exhibit mutual modulators. Profilin 2 (PFN2) has been reported to participate in epithelial-to-mesenchymal transition. Moreover, ETS proto-oncogene 1 (ets1) and lysine methyltransferase 5A (KMT5A) have been reported to contribute to high glucose-mediated endothelial injury and epithelial-to-mesenchymal transition. In this study, we hypothesize ets1 associates with KMT5A to modulate PFN2 transcription, thus participating in high glucose-mediated EndMT in glomerular endothelial cells. METHODS: Immunohistochemistry (IHC) was performed to detect protein levels in the kidney tissues and/or aorta tissues of human subjects and rats. Western blot, qPCR and immunofluorescence were performed using human umbilical vein endothelial cells (HUVECs). Chromatin immunoprecipitation (ChIP) assays and dual luciferase assays were performed to assess transcriptional activity. The difference between the groups was compared by two-tailed unpaired t-tests or one-way ANOVAs. RESULTS: Our data indicated that vimentin, αSMA, S100A4 and PFN2 levels were increased, and CD31 levels were reduced in glomerular endothelial cells of DN patients and rats. Our cell experiments showed that high glucose induced EndMT by augmenting PFN2 expression in HUVECs. Moreover, high glucose increased ets1 expression. si-ets1 suppressed high glucose-induced PFN2 levels and EndMT. ets1 overexpression-mediated EndMT was reversed by si-PFN2. Furthermore, ets1 was determined to associate with KMT5A. High glucose attenuated KMT5A levels and histone H4 lysine 20 methylation (H4K20me1), one of the downstream targets of KMT5A. KMT5A upregulation suppressed high glucose-induced PFN2 levels and EndMT. sh-KMT5A-mediated EndMT was counteracted by si-PFN2. Furthermore, H4K20me1 and ets1 occupied the PFN2 promoter region. sh-KMT5A cooperated with ets1 overexpression to activate PFN2 promoter activity. Our in vivo study demonstrated that KMT5A was reduced, while ets1 was augmented, in glomerular endothelial cells of DN patients and rats. CONCLUSIONS: The present study indicated that ets1 cooperated with KMT5A to transcribe PFN2, thus contributing to hyperglycemia-induced EndMT in the glomerular endothelial cells of DN patients and rats. Trial registration ChiCTR, ChiCTR2000029425. 2020/1/31, http://www.chictr.org.cn/showproj.aspx?proj=48548.

Deep learning model for classifying endometrial lesions.

BACKGROUND: Hysteroscopy is a commonly used technique for diagnosing endometrial lesions. It is essential to develop an objective model to aid clinicians in lesion diagnosis, as each type of lesion has a distinct treatment, and judgments of hysteroscopists are relatively subjective. This study constructs a convolutional neural network model that can automatically classify endometrial lesions using hysteroscopic images as input. METHODS: All histopathologically confirmed endometrial lesion images were obtained from the Shengjing Hospital of China Medical University, including endometrial hyperplasia without atypia, atypical hyperplasia, endometrial cancer, endometrial polyps, and submucous myomas. The study included 1851 images from 454 patients. After the images were preprocessed (histogram equalization, addition of noise, rotations, and flips), a training set of 6478 images was input into a tuned VGGNet-16 model; 250 images were used as the test set to evaluate the model's performance. Thereafter, we compared the model's results with the diagnosis of gynecologists. RESULTS: The overall accuracy of the VGGNet-16 model in classifying endometrial lesions is 80.8%. Its sensitivity to endometrial hyperplasia without atypia, atypical hyperplasia, endometrial cancer, endometrial polyp, and submucous myoma is 84.0%, 68.0%, 78.0%, 94.0%, and 80.0%, respectively; for these diagnoses, the model's specificity is 92.5%, 95.5%, 96.5%, 95.0%, and 96.5%, respectively. When classifying lesions as benign or as premalignant/malignant, the VGGNet-16 model's accuracy, sensitivity, and specificity are 90.8%, 83.0%, and 96.0%, respectively. The diagnostic performance of the VGGNet-16 model is slightly better than that of the three gynecologists in both classification tasks. With the aid of the model, the overall accuracy of the diagnosis of endometrial lesions by gynecologists can be improved. CONCLUSIONS: The VGGNet-16 model performs well in classifying endometrial lesions from hysteroscopic images and can provide objective diagnostic evidence for hysteroscopists.

Random quasi-phase-matching in polycrystalline media and its effects on pulse coherence properties.

Polycrystalline materials can mediate efficient frequency up-conversion for mid-infrared light. Motivated by the need to understand the properties of the harmonic and supercontinuum radiation from such media, we utilize realistic numerical simulations to reveal its complex temporal and spatial structure. We show that the generated radiation propagates in the form of long-duration pulse trains that can be difficult to compress and that optical filamentation in high-energy pulses gives rise to fine-structured beam profiles. We identify trends concerning pulse energy, sample length, and the microstructure of the material that can inform optimization for different applications.

Targeting the mu-Opioid Receptor for Cancer Treatment.

PURPOSE OF REVIEW: Opioids are still the most effective and widely used treatments for acute and chronic pain in cancer patients. This review focuses on the impact of opioids and mu-opioid receptors (MOR) on tumor progression and providing new ideas for targeting the MOR in cancer treatment. RECENT FINDINGS: Studies estimated that opioids facilitate tumor progression and are related to the worse prognosis in cancer patients. As the primary receptor of opioids, MOR is involved in the regulation of malignant transformation of tumors and participating in proliferation, invasion, metastasis, and angiogenesis. MOR may be a new molecular marker of malignant tumors and thus become a new target for cancer therapy, which may be beneficial to the outcomes of cancer patients.

Multi-layer silver nanowire/polyethylene terephthalate mesh structure for highly efficient transparent electromagnetic interference shielding.

Electromagnetic interference protection in optoelectronic devices is challenging because of the dual requirements of optical transmittance and high shielding effectiveness (SE). Herein, we propose a novel silver nanowire (AgNW)/polyethylene terephthalate (PET) multi-layer mesh pattern structure for transparent electromagnetic shielding obtained via laser marking and transfer printing. A three-layer composite shielding film with an optical transmittance of 67.8% exhibits a SE of 44 dB at 10 GHz, which is superior to most of the reported transparent shielding films composed of AgNWs to date. The newly designed multi-layer composite structure can enhance the transparent shielding properties of the shielding film via optimization of the AgNW distribution and the shielding film structure. It is expected that this multi-layer mesh composite structure will have splendid application prospects in electromagnetic shielding films, which require both light transmittance and high SE.

Transcriptome Analysis of Carbohydrate Metabolism Genes and Molecular Regulation of Sucrose Transport Gene LoSUT on the Flowering Process of Developing Oriental Hybrid Lily 'Sorbonne' Bulb.

The quality of Lily cut flower was determined by the quality of bulbs. During the process of vernalization and flower bud differentiation, sugar massively accumulated in the bulb, which influenced the bulb development. However, the details of sugar genes' regulation mechanism for these processes were not fully understood. Here, morphological physiology, transcriptomes and gene engineering technology were used to explore this physiological change. Seventy-two genes of 25 kinds of sugar metabolism-related genes were annotated after re-analyzing transcriptome data of Oriental hybrid lily 'Sorbonne' bulbs, which were generated on Hiseq Illumina 2000. The results showed that these genes were closely related to lily bulb vernalization and development. Combining gene expression pattern with gene co-expression network, five genes (Contig5669, Contig13319, Contig7715, Contig1420 and Contig87292) were considered to be the most potential signals, and the sucrose transporter gene (SUT) was the focus of this study. Carbohydrate transport pathway and genes' regulation mechanism were inferred through a physiological and molecular test. SUT seemed to be the sugar sensor that could sense and regulate sugar concentration, which might have effects on other genes, such as FT, LFY and so on. LoSUT2 and LoSUT4 genes were cloned from Oriental hybrid lily 'Sorbonne' by RACE, which was the first time for these genes in Oriental hybrid lily 'Sorbonne'. The physiological properties of these proteins were analyzed such as hydrophobicity and phosphorylation. In addition, secondary and tertiary structures of proteins were predicted, which indicated the two proteins were membrane proteins. Their cellular locations were verified through positioning the experiment of the fluorescent vector. They were highly expressed in cells around phloem, which illustrated the key role of these genes in sugar transport. Furthermore, transient expression assays showed that overexpressed LoSUT2 and LoSUT4 in Arabidopsis thaliana bloomed significantly earlier than the wild type and the expression of FT, SOC1 and LFY were also affected by LoSUT2 and LoSUT4, which indicated that LoSUT2 and LoSUT4 may regulate plants flowering time.

Robust Superhydrophobic/Superoleophilic Wrinkled Microspherical MOF@rGO Composites for Efficient Oil-Water Separation.

Graphene/MOF-based composite materials in three-dimensional (3D) architectures are promising for the treatment of oil-containing wastewater by absorption owing to their intrinsic properties of graphene and metal-organic frameworks (MOFs), such as high porosity, ultralow density, and facilely tailored superwettability. In this study, novel wrinkled 3D microspherical MOF@rGO composites with both superhydrophobic and superoleophilic properties were developed by embedding MOF nanoparticles between graphene oxide (GO) nanosheets, followed by high-temperature reduction self-assembly. The microspherical composites feature a unique micro/nano hierarchy consisting of crumpled reduced GO (rGO) nanosheets intercalated with well-dispersed MOF nanoparticles. Combined with the superwettability and abundant meso/microporosity, the peculiar architectures of wrinkled ZIF-8@rGO microspheres show very fast absorption rates and high sorption selectivity for organic solvents and oils from water.

Covalent Organic Framework-Covalent Organic Framework Bilayer Membranes for Highly Selective Gas Separation.

Covalent organic frameworks (COFs) have been proposed as alternative candidates for molecular sieving membranes due to their chemical stability. However, developing COF membranes with narrowed apertures close to the size of common gas molecules is a crucial task for selective gas separation. Herein, we demonstrate a new type of a two-dimensional layered-stacking COF-COF composite membrane in bilayer geometry synthesized on a porous support by successively regulating the growth of imine-based COF-LZU1 and azine-based ACOF-1 layers via a temperature-swing solvothermal approach. The resultant COF-LZU1-ACOF-1 bilayer membrane has much higher separation selectivity for H2/CO2, H2/N2, and H2/CH4 gas mixtures than the individual COF-LZU1 and ACOF-1 membranes due to the formation of interlaced pore networks, and the overall performance surpasses the Robeson upper bounds. The COF-LZU1-ACOF-1 bilayer membrane also shows high thermal and long-time stabilities.

Post-synthetic Modification of a Two-Dimensional Metal-Organic Framework via Photodimerization Enables Highly Selective Luminescent Sensing of Aluminum(III).

Reaction of Cd(NO3)2·4H2O with 5-fluoro-1,3-bis[2-(4-pyridyl)ethenyl]benzene (5-F-1,3-bpeb) and 1,3-benzenedicarboxylic acid (1,3-H2BDC) under the solvothermal conditions gave rise to a two-dimensional metal-organic framework (MOF) [{Cd2(5-F-1,3-bpeb)2(1,3-BDC)2}·0.5DMF·2H2O] n (1). Compound 1 was postmodified by a photodimerization reaction between 5-F-1,3-bpeb ligands to yield [{Cd2( syn-dftpmcp)(1,3-BDC)2}·0.5DMF·H2O] n ( syn-dftpmcp = syn-3,4,12,13-tetrakis(4-pyridyl)-8,17-bisfluoro-1,2,9,10-diethano[2.2]metacyclophane) (2). Compounds 1 and 2 have 2D networks built from linking one-dimensional [Cd2(1,3-BDC)2] n chains via 5-F-1,3-bpeb or syn-dftpmcp bridges. After such a post-synthetic modification, compound 2, relative to 1, can probe Al3+ by using a luminescent quenching approach with much higher selectivity and sensitivity.

Conductivity enhancement of silver nanowire networks via simple electrolyte solution treatment and solvent washing.

As a promising replacement material for indium tin oxide in flexible electronics, silver nanowires (AgNWs) usually need complicated post-treatment to reduce the high contact resistance across the intersections when used as transparent conductive films. In this work, a widely applicable nano-joining method for improving the overall conductivity of AgNW networks with different kinds of electrolyte solutions is presented. By treatment with an electrolyte solution with appropriate ionic strengths, the insulating surfactant layer (polyvinylpyrrolidone, PVP) on the AgNWs could be desorbed, and the AgNW network could be densified. The sheet resistance of the AgNW film on a glass slide is reduced by 60.9% (from 67.5 to 26.4 Ohm sq-1) with a transmittance of 92.5%. High-resolution transmission electron microscopy analysis indicates that atomic diffusion occurs at the intersection of two AgNWs. Thus, metallurgical bonding on the nanometer scale is achieved across the junctions of the AgNWs, leading to a significant enhancement in the conductivity of the AgNW network.

High-Flux Membranes Based on the Covalent Organic Framework COF-LZU1 for Selective Dye Separation by Nanofiltration.

Covalent organic frameworks (COFs) are attractive candidates for advanced water-treatment membranes owing to their high porosity and well-organized channel structures. Herein, the continuous two-dimensional imine-linked COF-LZU1 membrane with a thickness of only 400 nm was prepared on alumina tubes by in situ solvothermal synthesis. The membrane shows excellent water permeance (ca. 760 L m-2 h-1 MPa-1 ) and favorable rejection rates exceeding 90 % for water-soluble dyes larger than 1.2 nm. The water permeance through the COF-LZU1 membrane is much higher than that of most membranes with similar rejection rates. Long-time operation demonstrates the outstanding stability of the COF-LZU1 membrane. As the membrane has no selectivity for hydrated salt ions (selectivity <12 %), it is also suitable for the purification of dye products from saline solutions. The excellent performance and the outstanding water stability render the COF-LZU1 membrane an interesting system for water purification.