Enhancing the Electrospinnability of Low Molecular Weight Polymers Using Small Effective Cross-Linkers

The electrospinning of continuous fibers normally requires the presence of a network of topological entanglements in solution, limiting the spinnability of low molecular weight polymers. Here, we show that a supramolecular approach can improve, and even render possible, the electrospinning of low molecular weight polymers, illustrated here with poly­(4-vinylpyridine) (P4VP), by creating effective (i.e., physical) cross-links via hydrogen bonding or coordination interactions in solution using small molecules. The addition to P4VP solutions in dimethyl­formamide of 4,4′-biphenol (BiOH), which hydrogen bonds to P4VP, and nitromethane, a poor solvent for P4VP that increases BiOH hydrogen bonding to P4VP, decreases the concentration needed to prepare fibers of 50 kg/mol P4VP by a factor of 2 and enables the formation of unbeaded fibers. Hydrogen bonding in solution is quantified by infrared spectroscopy, and the impact of the supramolecular interactions on the P4VP concentration needed to form a physical network is shown by rheological studies. BiOH can also be removed by sublimation without damaging the fibers. Replacing BiOH by 4-hydroxy-4′-biphenyl­carboxylic acid (HBCA), whose acid group hydrogen bonds more strongly than OH to P4VP, or by just 1% ZnCl₂ (relative to pyridine), which promotes metal coordination interactions with P4VP, improves the cross-linking efficiency still further. Most spectacularly, HBCA enables the electrospinning of unbeaded fibers of P4VP with the very low molecular weight of 5.2 kg/mol, which is well below the entanglement molecular weight. These results establish the supramolecular cross-linking approach as a powerful strategy for preparing nanofibers of pure polymers having limited electrospinnability

Image_2_Advanced primary vaginal squamous cell carcinoma: A case report and literature review.jpg

BackgroundVaginal carcinoma is a gynecological malignancy with low incidence, and there are few relevant and specific guidelines for vaginal cancer in our country and abroad. Here, we report the case who was diagnosed with advanced, primary vaginal squamous cell carcinoma and underwent integrated treatment successfully.Case introductionA 64-year-old Chinese woman underwent subtotal hysterectomy for uterine fibroids in 1998 and laparoscopic extensive residual cervical resection, bilateral ovarian salpingectomy, and pelvic lymph node dissection for residual cervical adenocarcinoma (stage IB1) in the First Affiliated Hospital of China Medical University in 2018. There was no postoperative review. The patient experienced vaginal discharge in March 2020, and vaginal bleeding occurred in July 2020. Our patient was diagnosed with stage IVA vaginal squamous cell carcinoma, based on a gynecological examination, colposcopy biopsy with histopathological examination, computed tomography scan, and tumor marker levels by two professors. After three phases of treatment (sequential treatment with chemotherapy plus radiotherapy, chemotherapy combined with immune checkpoint inhibitors, and immune checkpoint inhibitors combined with tyrosine kinase inhibitors therapy), her condition improved. Her current state is generally good, and she has achieved complete remission.ConclusionWe report a rare case of a patient with primary advanced vaginal carcinoma combined with cervical adenocarcinoma. The patient was treated for approximately 2 years, and her personalized treatment showed promising results. We will continue to follow up with the patient and monitor her response to the current treatment process.</p

Smart Energy Clays: Chemical Vapor Deposition of PEDOT in Expanded Vermiculite Blocks for Electrochemical Energy Storage

With rapid development of sustainable energy storage systems and intelligent energy supply equipment, supercapacitors have attracted wide attention while still suffering from low specific capacitance, poor kinetic diffusion, and charge transfer. Here, we demonstrate the concept of integrating conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) into insulation voids in expanded vermiculite blocks, achieving PEDOT-intercalated vermiculite electrodes for pseudocapacitive energy storage. The electrodes show rapid kinetic diffusion and charge transfer as well as high areal specific capacitance of 2592 mF cm–2 at the current density of 3 mA cm–2, surpassing most of the state-of-the-art electrodes for supercapacitors. The prepared electrodes were assembled into a symmetrical supercapacitor which shows a specific capacitance of 412.8 mF cm–2 at a current density of 2 mA cm–2 with a high energy density of 30.3 μW h cm–2 at a high power density of 3001.8 μW cm–2. This work realizes the preparation of electrochemical energy storage electrode materials on insulating layer minerals, which is a fruitful tactic and opens the door to the creation of more supercapacitor electrodes

Image_1_Advanced primary vaginal squamous cell carcinoma: A case report and literature review.jpg

BackgroundVaginal carcinoma is a gynecological malignancy with low incidence, and there are few relevant and specific guidelines for vaginal cancer in our country and abroad. Here, we report the case who was diagnosed with advanced, primary vaginal squamous cell carcinoma and underwent integrated treatment successfully.Case introductionA 64-year-old Chinese woman underwent subtotal hysterectomy for uterine fibroids in 1998 and laparoscopic extensive residual cervical resection, bilateral ovarian salpingectomy, and pelvic lymph node dissection for residual cervical adenocarcinoma (stage IB1) in the First Affiliated Hospital of China Medical University in 2018. There was no postoperative review. The patient experienced vaginal discharge in March 2020, and vaginal bleeding occurred in July 2020. Our patient was diagnosed with stage IVA vaginal squamous cell carcinoma, based on a gynecological examination, colposcopy biopsy with histopathological examination, computed tomography scan, and tumor marker levels by two professors. After three phases of treatment (sequential treatment with chemotherapy plus radiotherapy, chemotherapy combined with immune checkpoint inhibitors, and immune checkpoint inhibitors combined with tyrosine kinase inhibitors therapy), her condition improved. Her current state is generally good, and she has achieved complete remission.ConclusionWe report a rare case of a patient with primary advanced vaginal carcinoma combined with cervical adenocarcinoma. The patient was treated for approximately 2 years, and her personalized treatment showed promising results. We will continue to follow up with the patient and monitor her response to the current treatment process.</p

Cluster-MLP: An Active Learning Genetic Algorithm Framework for Accelerated Discovery of Global Minimum Configurations of Pure and Alloyed Nanoclusters

Structural characterization of nanoclusters is one of the major challenges in nanocluster modeling owing to the multitude of possible configurations of arrangement of cluster atoms. The genetic algorithm (GA), a class of evolutionary algorithms based on the principles of natural evolution, is a commonly employed search method for locating the global minimum configuration of nanoclusters. Although a GA search at the DFT level is required for the accurate description of a potential energy surface to arrive at the correct global minimum configuration of nanoclusters, computationally expensive DFT evaluation of the significantly larger number of cluster geometries limits its practicability. Recently, machine learning potentials (MLP) that are learned from DFT calculations gained significant attention as computationally cheap alternative options that provide DFT level accuracy. As the accuracy of the MLP predictions is dependent on the quality and quantity of the training DFT data, active learning (AL) strategies have gained significant momentum to bypass the need of large and representative training data. In this application note, we present Cluster-MLP, an on-the-fly active learning genetic algorithm framework that employs the Flare++ machine learning potential (MLP) for accelerating the GA search for global minima of pure and alloyed nanoclusters. We have used a modified version the Birmingham parallel genetic algorithm (BPGA) for the nanocluster GA search which is then incorporated into distributed evolutionary algorithms in Python (DEAP), an evolutionary computational framework for fast prototyping or technical experiments. We have shown that the incorporation of the AL framework in the BPGA significantly reduced the computationally expensive DFT calculations. Moreover, we have shown that both the AL-GA and DFT-GA predict the same global minima for all the clusters we tested

Polyanionic Clusters [M(P₄Mo₆)₂] (M = Ni, Cd) as Effective Molecular Catalysts for the Electron-Transfer Reaction of Ferricyanide to Ferrocyanide

Three polyanion-containing supramolecular hybrids, (H₂bpp)₆{Ni­[Mo^V₆O₁₃(OH)₂(HPO₄)₃(H₂PO₄)]₂}₂·13H₂O [<b>1</b>; bpp = 1,3-bis­(4-pyridyl)­propane], (H₂bpp)₅{Cd­[Mo^V₆O₁₅(HPO₄)₃(H₂PO₄)]₂}­{Cd­[Mo^V₆O₁₅(HPO₄)₄]₂}·10H₂O (<b>2</b>), (H₂bpp)₂[Cd­(H₂O)­Cd­(H₂O)₂]₂{Cd­[Mo^V₆O₁₂(OH)₃(HPO₄)₂(PO₄)₂]₂}·8H₂O (<b>3</b>), have been synthesized and characterized. The inorganic moieties in <b>1</b>–<b>3</b> belong to the reduced {M­[P₄Mo^V₆X₃₁]₂}^<i>n</i>− (M = Ni, Cd) clusters. Three supramolecular hybrids exhibit reversible multiple electron-transfer behaviors and have been used as heterogeneous molecular catalysts for the reduction of ferricyanide (Fe^III) to ferrocyanide (Fe^II) with Na₂S₂O₃ as a reductant. The experimental results indicate that hybrid materials <b>1</b>–<b>3</b> have higher catalytic activity toward the reaction. These low-cost catalysts can effectively decrease the activation energy of this reaction. These values are calculated to be 25.35 kJ·mol^–1 for hybrid <b>2</b>, 84.11 kJ·mol^–1 for hybrid <b>1</b>, and 83.14 kJ·mol^–1 for hybrid <b>3</b>. The reaction mechanism is subjected to a surface-catalytic process

Molecular-Level Study of Photoorientation in Hydrogen-Bonded Azopolymer Complexes

To optimize azobenzene-containing materials for applications such as rewritable waveguides and holographic data storage, it is imperative to understand the effect of the azobenzene structure on the photoresponse of the material. Supramolecular materials, in which a complexed photoactive azobenzene controls the motion or other properties of a passive polymer, are uniquely convenient for studying the impact of specific chemical modifications. Here, we use polarization modulation infrared structural absorbance spectroscopy (PM-IRSAS) to study hydrogen-bonded supramolecular azobenzene complexes using poly­(4-vinylpyridine) (P4VP) as a model polymer. We show that changing the tail group from hydrogen (A_H) to cyano (A_CN) induces greater angular redistribution of the chromophores and, remarkably, provokes P4VP pyridine ring orientation. Increasing the degree of complexation decreases the saturated orientation of both A_H and A_CN, whereas for P4VP/A_CN it increases the pyridine orientation as well as the orientation stability of both components. These results explain the contrasting photoinduced birefringence behavior previously observed for these complexes and identify azo–azo intermolecular interactions as the main reason. To our knowledge, this is the first molecular-level spectroscopic analysis of the contrasting contributions of azobenzenes to the photoorientation of supramolecular azopolymer complexes and the first report of the large impact of small molecular changes on the capacity of azo dyes to transfer light-induced orientation to a photopassive polymer

Additional file 5 of The revised-risk analysis index as a predictor of major morbidity and mortality in older patients after abdominal surgery: a retrospective cohort study

Additional file 5 Supplemental Digital Content 5. Factors in association with postoperative MMM (univariate analyses)

Distribution and potential eco-risk of chromium and nickel in sediments after impoundment of Three Gorges Reservoir, China

<p>The impoundment of the Three Gorges Reservoir (TGR) altered the hydrodynamic conditions and modulated the accumulation and behaviors of heavy metals in the sediments. In this study, the sediments from the riparian and submerged areas of the entire TGR mainstream were collected in 2014 to investigate the spatial distribution of chromium (Cr) and nickel (Ni), and to assess their contamination state and potential eco-risk to aquatic environment by multiple indices. Results showed that the concentrations of Cr and Ni in the sediments increased toward the dam. The concentrations of Cr were significantly higher in the riparian sediments than in the submerged sediments, whereas the Ni concentrations were comparable. The relatively high storages of Cr and Ni in the sediments existed near the dam. The physiochemical properties of sediments and local human activities controlled the spatial variations of Cr and Ni in the sediments. Currently, the TGR sediments are not heavily contaminated by Cr and Ni and show low eco-risk. Nevertheless, considering the decrease in sediment loads from the upper Yangtze River and the rapid urbanization in the TGR catchment, much more attentions should be paid to the geochemical behaviors and the eco-risk of Cr and Ni in the sediments.</p

Polyanionic Clusters [M(P₄Mo₆)₂] (M = Ni, Cd) as Effective Molecular Catalysts for the Electron-Transfer Reaction of Ferricyanide to Ferrocyanide

Three polyanion-containing supramolecular hybrids, (H₂bpp)₆{Ni­[Mo^V₆O₁₃(OH)₂(HPO₄)₃(H₂PO₄)]₂}₂·13H₂O [<b>1</b>; bpp = 1,3-bis­(4-pyridyl)­propane], (H₂bpp)₅{Cd­[Mo^V₆O₁₅(HPO₄)₃(H₂PO₄)]₂}­{Cd­[Mo^V₆O₁₅(HPO₄)₄]₂}·10H₂O (<b>2</b>), (H₂bpp)₂[Cd­(H₂O)­Cd­(H₂O)₂]₂{Cd­[Mo^V₆O₁₂(OH)₃(HPO₄)₂(PO₄)₂]₂}·8H₂O (<b>3</b>), have been synthesized and characterized. The inorganic moieties in <b>1</b>–<b>3</b> belong to the reduced {M­[P₄Mo^V₆X₃₁]₂}^<i>n</i>− (M = Ni, Cd) clusters. Three supramolecular hybrids exhibit reversible multiple electron-transfer behaviors and have been used as heterogeneous molecular catalysts for the reduction of ferricyanide (Fe^III) to ferrocyanide (Fe^II) with Na₂S₂O₃ as a reductant. The experimental results indicate that hybrid materials <b>1</b>–<b>3</b> have higher catalytic activity toward the reaction. These low-cost catalysts can effectively decrease the activation energy of this reaction. These values are calculated to be 25.35 kJ·mol^–1 for hybrid <b>2</b>, 84.11 kJ·mol^–1 for hybrid <b>1</b>, and 83.14 kJ·mol^–1 for hybrid <b>3</b>. The reaction mechanism is subjected to a surface-catalytic process