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1.
Chemistry ; 30(13): e202302834, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38141178

RESUMEN

The formation of a five- or six-membered ring is known to stabilize unstable molecular structures such as hemiacetals. This idea can also be extended to stabilize other high-coordinated p-block element species. Herein, we synthesized two novel polycyclic organophosphorus heterocycles via Staudinger-type annulations. Reactions of either ortho-phosphinoarenesulfonyl fluorides 1 or ortho-phosphinobenzoic acid methyl esters 4 with ortho-azidophenols 2 gave rise to penta-coordinated P(V) heterocycles, benzo-benzo-1,2,3-thiazaphospholo-1,3,2-oxazaphosphole (B-B-TAP-OAP) 3 and benzo-benzo-1,2-azaphospholo-1,3,2-oxazaphosphol-12-one (B-B-AP-OAP) 5 in satisfactory yields. It is remarkable that heterocycles 3 and 5 are both bench-stable and exhibit considerable stability in a 10 % aqueous tetrahydrofuran solution. Preliminary computational studies disclosed that the formation of nitrogen gas is the key driving force for the annulations. In addition, the formation of a strong Si-F bond is another contributor to the annulation of 1 and 2.

2.
Acad Radiol ; 2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-38057180

RESUMEN

RATIONALE AND OBJECTIVES: To develop a monitoring model using radiomics analysis based on longitudinal B-mode ultrasound (BUS) and shear wave elastography (SWE) to early predict pathological response to neoadjuvant chemotherapy (NAC) in breast cancer patients. MATERIALS AND METHODS: In this prospective study, 112 breast cancer patients who received NAC between September 2016 and March 2022 were included. The BUS and SWE data of breast cancer were obtained prior to treatment as well as after two and four cycles of NAC. Radiomics features were extracted followed by measuring the changes in radiomics features compared to baseline after the second and fourth cycles of NAC (△R [C2], △R [C4]), respectively. The delta radiomics signatures were established using a support vector machine classifier. RESULTS: The area under receiver operating characteristic curve (AUC) values of △RBUS (C2) and △RBUS (C4) for predicting the response to NAC were 0.83 and 0.84, while those of △RSWE (C2) and △RSWE (C4) were 0.88 and 0.90, respectively. △RSWE exhibited significantly superior performance to △RBUS for predicting NAC response (Delong test, p < 0.01). No significant differences were observed in the performances between △R (C2) and △R (C4) based on BUS or SWE data. The longitudinal dual-modal ultrasound radiomics (LDUR) model had an excellent discrimination, good calibration and clinical usefulness, with the AUC, sensitivity and specificity of 0.97, 95.52% and 91.11%, respectively. CONCLUSION: The LDUR model achieved excellent performance in predicting the pathological response to chemotherapy during the early stages of NAC for breast cancer.

3.
Chem Commun (Camb) ; 59(73): 10968-10971, 2023 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-37609958

RESUMEN

Herein, an oxygen defect-modulated zinc oxide sonosensitizer is designed, which enhances the absorbance of ultrasound energy and suppresses the recombination of ultrasound-initiated electrons and holes to promote reactive oxygen species yield. It achieves a high tumor inhibition efficiency of 79.9%, which exhibits a potential application for sonodynamic cancer therapy.


Asunto(s)
Nanopartículas , Neoplasias , Óxido de Zinc , Oxígeno , Especies Reactivas de Oxígeno , Electrones , Neoplasias/tratamiento farmacológico
4.
J Colloid Interface Sci ; 651: 191-199, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37542894

RESUMEN

Imbalances in the intracellular environment caused by high levels of glucose, H2O2, and hypoxia can greatly impact cancer development and treatment. However, there is limited research on regulating the levels of these species simultaneously in tumor cells. Here, a pH-responsive nanozyme-enzyme hybrid system was developed to regulate intracellular glucose, H2O2 and O2. The system, named DMSN@Cu-CeO2@GOx, consists of Cu-CeO2 nanoparticles and glucose oxidase (GOx) immobilized in dendritic mesoporous silica (DMSN) spheres. GOx efficiently consumes glucose in tumor cells, causing a drop in pH and producing a significant amount of H2O2. Cu-CeO2 then catalyzes the conversion of H2O2 to O2 due to its high catalase-like (CAT) activity in weakly acidic conditions. The process was monitored by fluorescence probes, and the mechanism was investigated through fluorescence spectroscopy and confocal laser scanning microscopy. The cascade catalytic system with excellent biocompatibility continuously consumes glucose and elevates the level of O2 in cells. This hybrid nanomaterial offers a means to regulate the glucose/H2O2/O2 levels in cells and may provide insights into starvation therapy by modulating reactive species within cells.


Asunto(s)
Glucosa , Neoplasias , Humanos , Peróxido de Hidrógeno , Glucosa Oxidasa/química , Neoplasias/terapia , Dióxido de Silicio/química , Catálisis , Línea Celular Tumoral
5.
Org Lett ; 25(28): 5236-5241, 2023 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-37428151

RESUMEN

The reduction of phosphine oxides without the use of highly reactive reductants represents a safer and more sustainable solution for recycling of organophosphorus compounds. Herein, we disclose an N,N,N',N'-tetramethylethylenediamine (TMEDA)-mediated reduction via an unusual intermolecular hydride transfer. Mechanistic studies suggest that TMEDA serves as a hydride donor, while the P(V) halophosphonium salt acts as the hydride acceptor. This methodology provides a scalable and efficient protocol to reduce phosphine oxides under mild conditions.

6.
Acad Radiol ; 30 Suppl 2: S50-S61, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37270368

RESUMEN

RATIONALE AND OBJECTIVES: To carry out radiomics analysis/deep convolutional neural network (CNN) based on B-mode ultrasound (BUS) and shear wave elastography (SWE) to predict response to neoadjuvant chemotherapy (NAC) in breast cancer patients. MATERIALS AND METHODS: In this prospective study, 255 breast cancer patients who received NAC between September 2016 and December 2021 were included. Radiomics models were designed using a support vector machine classifier based on US images obtained before treatment, including BUS and SWE. And CNN models also were developed using ResNet architecture. The final predictive model was developed by combining the dual-modal US and independently associated clinicopathologic characteristics. The predictive performances of the models were assessed with five-fold cross-validation. RESULTS: Pretreatment SWE performed better than BUS in predicting the response to NAC for breast cancer for both the CNN and radiomics models (P < 0.001). The predictive results of the CNN models were significantly better than the radiomics models, with AUCs of 0.72 versus 0.69 for BUS and 0.80 versus 0.77 for SWE, respectively (P = 0.003). The CNN model based on the dual-modal US and molecular data exhibited outstanding performance in predicting NAC response, with an accuracy of 83.60% ± 2.63%, a sensitivity of 87.76% ± 6.44%, and a specificity of 77.45% ± 4.38%. CONCLUSION: The pretreatment CNN model based on the dual-modal US and molecular data achieved excellent performance for predicting the response to chemotherapy in breast cancer. Therefore, this model has the potential to serve as a non-invasive objective biomarker to predict NAC response and aid clinicians with individual treatments.


Asunto(s)
Neoplasias de la Mama , Aprendizaje Profundo , Humanos , Femenino , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/patología , Terapia Neoadyuvante , Estudios Prospectivos , Ultrasonografía/métodos , Estudios Retrospectivos
7.
J Am Chem Soc ; 145(20): 11431-11439, 2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37162483

RESUMEN

Covalent organic frameworks (COFs) have showcased great potential in diverse applications such as separation and catalysis, where mass transfer confined in their pore channels plays a significant role. However, anisotropic orientation usually occurs in polycrystalline COFs, and perpendicular alignment of COF pore channels is ultimately desired to maximize their performance. Herein, we demonstrate a strategy, solvent vapor annealing, to reorient COF pore channels from anisotropic orientation to perpendicular alignment. COF thin films are first synthesized to have flexible N-H bonds in their skeletons, thus having structural mobility to enable molecular rearrangement. A solvent with low relative permittivity and a conjugated structure is then identified to have a strong affinity toward the COFs, allowing its vapor to easily penetrate into the COF interlayers. The solvent vapor weakens the π-π interaction and consequently allows the COF monolayers to dissociate. The COF monolayers undergo a reorientation process that converts from random stacking into the face-on stacking fashion, in which the through COF pores are perpendicularly aligned. The aligned COF film exhibits high separation precision toward ions featuring a size difference down to 2 Å, which is 8 times higher than that of the anisotropically oriented counterpart. This work opens up an avenue for COF orientation regulation by solvent vapor annealing and reveals the essential role of the perpendicular alignment of COF pore channels to enable precision separations.

8.
Eur J Radiol ; 163: 110811, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37062204

RESUMEN

OBJECTIVE: This study aimed to investigate whether the extracellular volume fraction (ECV) determined using enhanced computed tomography (CT) can predict the pathologic grade of rectal adenocarcinoma. METHODS: We prospectively analyzed 43 patients with rectal adenocarcinoma confirmed surgically and pathologically and who had undergone preoperative enhanced CT imaging. The plain, arterial, venous, and balance phase values were recorded, and the absolute contrast-enhanced CT differences ΔS1 = HUarterial phase-HUplain scan, ΔS2 = HUvenous phase-HUplain scan, ΔS3 = HUbalance phase-HUplain scan were obtained. The ECV of the primary lesion was calculated by measuring the CT values of the regions of interest in the plain and balance phases. Patients were allocated to either a low-grade or a high-grade group based on the histologic grading standard for colorectal adenocarcinoma (nonspecial type, World Health Organization 2010 standard). The differences in the parameters between the two groups were evaluated for statistical significance. A receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficiency. RESULTS: The 43 enrolled patients [12 in the high-grade group (27.9%) and 31 in the low-grade group (72.1%)] had an average age of 64.47 years. The arterial phase (P = 0.005) as well as ΔS1 (P = 0.006), ΔS3 (P = 0.021), and ECV (P< 0.001) differed significantly between the high-grade and low-grade groups, with ECV (P< 0.001) and ΔS3 (P = 0.042) being positively correlated with the pathologic grade and arterial phase (P = 0.025) and ΔS1 (P = 0.005) being negatively correlated. The ROC curve demonstrated that the best efficacy in evaluating the pathologic grade of rectal cancer was achieved by ECV, with an area under the curve of 0.892 (95% confidence interval: 0.757-1.000). The diagnostic threshold was 34.42%, sensitivity was 91.7%, and specificity was 83.9%. CONCLUSION: The use of enhanced CT to obtain ECV is helpful in predicting the pathologic grade of rectal cancer; however, this result has to be confirmed in a study with a larger sample size.


Asunto(s)
Adenocarcinoma , Neoplasias Colorrectales , Neoplasias del Recto , Humanos , Persona de Mediana Edad , Tomografía Computarizada por Rayos X , Neoplasias del Recto/diagnóstico por imagen , Neoplasias del Recto/cirugía , Neoplasias del Recto/patología , Adenocarcinoma/diagnóstico por imagen , Adenocarcinoma/cirugía , Adenocarcinoma/patología , Curva ROC , Estudios Retrospectivos
9.
Interdiscip Sci ; 15(2): 249-261, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36906712

RESUMEN

The search for potential drug-disease associations (DDA) can speed up drug development cycles, reduce costly wasted resources, and accelerate disease treatment by repurposing existing drugs that can control further disease progression. As technologies such as deep learning continue to mature, many researchers tend to use emerging technologies to predict potential DDA. The performance of DDA prediction is still challenging and there is some space for improvement due to issues such as the small number of existing associations and possible noise in the data. To better predict DDA, we propose a computational approach based on hypergraph learning with subgraph matching (HGDDA). In particular, HGDDA first extracts feature subgraph information in the validated drug-disease association network and proposes a negative sampling strategy based on similarity network to reduce the data imbalance. Second, the hypergraph Unet module is used by extracting Finally, the potential DDA is predicted by designing a hypergraph combination module to convolution and pooling the two constructed hypergraphs separately, and calculating the difference information between the subgraphs using cosine similarity for node matching. The performance of HGDDA is verified under two standard datasets by 10-fold cross-validation (10-CV), and the results outperform existing drug-disease prediction methods. In addition, to validate the overall utility of the model, the top 10 drugs for the specific disease are predicted through the case study and validated using the CTD database.


Asunto(s)
Algoritmos , Biología Computacional , Bases de Datos Factuales , Biología Computacional/métodos
10.
Pharmaceutics ; 14(6)2022 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-35745771

RESUMEN

Ultrasound contrast agents are valuable for diagnostic imaging and drug delivery. Generally, chemically synthesized microbubbles (MBs) are micro-sized particles. Particle size is a limiting factor for the diagnosis and treatment of many extravascular diseases. Recently, gas vesicles (GVs) from some marine bacteria and archaea have been reported as novel nanoscale contrast agents, showing great potential for biomedical applications. However, most of the GVs reported in the literature show poor contrast imaging capabilities due to their small size, especially for the in vivo condition. In this study, we isolated the rugby-ball-shaped GVs from Halobacteria NRC-1 and characterized their contrast imaging properties in vitro and in vivo. Our results showed that GVs could produce stable and strong ultrasound contrast signals in murine liver tumors using clinical diagnostic ultrasound equipment at the optimized parameters. Interestingly, we found these GVs, after systemic administration, were able to perfuse the ischemic region of a tumor where conventional lipid MBs failed, producing a 6.84-fold stronger contrast signal intensity than MBs. Immunohistochemistry staining assays revealed that the nanoscale GVs, in contrast to the microscale MBs, could penetrate through blood vessels. Thus, our study proved these biosynthesized GVs from Halobacterium NRC-1 are useful for future molecular imaging and image-guided drug delivery.

11.
Sensors (Basel) ; 22(11)2022 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-35684919

RESUMEN

Convolutional Neural Networks (CNNs) are popular models that are widely used in image classification, target recognition, and other fields. Model compression is a common step in transplanting neural networks into embedded devices, and it is often used in the retraining stage. However, it requires a high expenditure of time by retraining weight data to atone for the loss of precision. Unlike in prior designs, we propose a novel model compression approach based on Simonk-means, which is specifically designed to support a hardware acceleration scheme. First, we propose an extension algorithm named Simonk-means based on simple k-means. We use Simonk-means to cluster trained weights in convolutional layers and fully connected layers. Second, we reduce the consumption of hardware resources in data movement and storage by using a data storage and index approach. Finally, we provide the hardware implementation of the compressed CNN accelerator. Our evaluations on several classifications show that our design can achieve 5.27× compression and reduce 74.3% of the multiply-accumulate (MAC) operations in AlexNet on the FASHION-MNIST dataset.


Asunto(s)
Compresión de Datos , Redes Neurales de la Computación , Aceleración , Algoritmos , Fenómenos Físicos
12.
Eur Radiol ; 32(9): 5986-5996, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35364714

RESUMEN

OBJECTIVE: To determine the ability of conventional ultrasound (US) combined with shear wave elastography (SWE) to reveal axillary status after neoadjuvant chemotherapy (NAC) in breast cancer patients. METHODS: From September 2016 to December 2021, 201 patients with node-positive breast cancer who underwent NAC were enrolled in this prospective study. Conventional US features of axillary lymph nodes and SWE characteristics of breast lesions after NAC were analyzed. The diagnostic performances of US, SWE, and their combination were assessed using multivariate logistic regression and receiver operator characteristic curve (ROC) analyses. RESULTS: The area under the ROC curve (AUC) for the ability of conventional US features to determine axillary status after NAC was 0.82, with a sensitivity of 85.23%, a specificity of 67.39%, and an accuracy of 76.11%. Shear wave velocity (SWV) displayed moderate performance for predicting axilla status after NAC with SWVmean demonstrating an AUC of 0.85. Cortical thickness and shape of axillary nodes and SWVmean of breast tumors were independently associated with axillary nodal metastasis after NAC. Compared to conventional US, the combination of conventional US of axillary lymph nodes with SWE of breast lesions achieved a significantly higher AUC (0.90 vs 0.82, p < 0.01, Delong's test) with a sensitivity of 87.50%, improved specificity of 82.61% and accuracy of 85.00%. CONCLUSIONS: Breast SWE was independently associated with residual metastasis of axillary node after NAC in patients with initially diagnosed positive axilla. Combining SWE with conventional US showed good diagnostic performance for axillary node disease after NAC. KEY POINTS: • Breast SWE can serve as a supplement to axilla US for the evaluation of the axilla after NAC. • The combination of axilla US with breast SWE may be a promising method to facilitate less-invasive treatment in patients receiving NAC.


Asunto(s)
Neoplasias de la Mama , Diagnóstico por Imagen de Elasticidad , Axila/patología , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/tratamiento farmacológico , Diagnóstico por Imagen de Elasticidad/métodos , Femenino , Humanos , Ganglios Linfáticos/diagnóstico por imagen , Ganglios Linfáticos/patología , Metástasis Linfática/patología , Terapia Neoadyuvante/métodos , Estudios Prospectivos
13.
J Orthop Surg Res ; 17(1): 104, 2022 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-35183215

RESUMEN

BACKGROUND: Present work was aimed to gather accessible evidence on the eradication rates and related postoperative complications of antibiotic-loaded calcium sulfate (CS) as an implant in the treatment of chronic osteomyelitis (COM). METHODS: Databases including PubMed, EMBASE, Medline, Ovid and Cochrane library were searched from their dates of initiation until November 2021. Two independent authors scrutinized the relevant studies based on the effectiveness of radical debridement combined with antibiotic-loaded CS for COM; data extraction and quality assessment of the Methodological Index for Non-Randomized Studies (MINORS) criteria were also performed by the authors. In addition, clinical efficacy mainly depended on the evaluation of eradication rates and complications, and all the extracted data are pooled and analyzed by STATA 16.0. RESULTS: A total of 16 studies with 917 patients (920 locations) were recruited, with an overall eradication rate of 92%. Moreover, the overall reoperation rate, overall refracture rate, overall delayed wound healing rate, and the rate of aseptic wound leakage were 9.0%, 2.0%, 20.0%, and 12.0%, respectively. Moreover, the choice of tobramycin-loaded CS or vancomycin combined with gentamicin-loaded CS did not affect the eradication rate, and the incidence of postoperative complications in COM patients (all [Formula: see text]). The general quality of the included studies was fair. CONCLUSIONS: Our meta-analysis indicated that the overall eradication rate of COM treated with antibiotic-loaded CS was 92%. Delayed healing is the most common postoperative complication. The choice of tobramycin-loaded CS or vancomycin combined with gentamicin-loaded CS did not affect the eradication rate and the incidence of postoperative complications in COM patients.


Asunto(s)
Antibacterianos/uso terapéutico , Sulfato de Calcio/uso terapéutico , Osteomielitis/tratamiento farmacológico , Gentamicinas/uso terapéutico , Humanos , Incidencia , Complicaciones Posoperatorias/epidemiología , Tobramicina/uso terapéutico , Vancomicina/uso terapéutico
14.
Gynecol Oncol ; 162(1): 107-112, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33966893

RESUMEN

OBJECTIVE: To assess the diagnostic performance and inter-observer agreement of the American College of Radiology (ACR) Ovarian-Adnexal Reporting and Data System Ultrasound (O-RADS US). METHODS: From January 2016 to December 2018 a total of 1054 adnexal lesions in 1035 patients with pathologic results from two hospitals were retrospectively included. Each lesion was assigned to an O-RADS US category according to the criteria. Kappa (κ) statistics were applied to assess inter-observer agreement between a less experienced and an expert radiologist. RESULTS: Of the 1054 adnexal lesions, 750 were benign and 304 were malignant. The malignancy rates of O-RADS 5, O-RADS 4, O-RADS 3, and O-RADS 2 lesions were 89.57%, 34.46%, 1.10%, and 0.45% respectively. Area under the receiver operating characteristic curve was 0.960 (95% CI, 0.947-0.971). The optimal cutoff value for predicting malignancy was >O-RADS 3 with a sensitivity and specificity of 98.7% (95% CI, 0.964-0.996) and 83.2% (95% CI, 0.802-0.858) respectively. When sub-classifying multilocular cysts and smooth solid lesions in O-RADS 4 lesions as O-RADS 4a lesions and the rest cystic lesions with solid components as O-RADS 4b lesions, the malignancy rate were 17.02% and 42.57% respectively, which showed better risk stratification (P < 0.001). The inter-observer agreement between a less-experienced and an expert radiologist of O-RADS categorization was good (κ = 0.714). CONCLUSIONS: The ACR O-RADS US provides effective malignancy risk stratification for adnexal lesions with high reliability for radiologists with different experience. Sub-grouping of O-RADS 4 lesions into two groups facilitated better stratification of the intermediate risk.


Asunto(s)
Anexos Uterinos/diagnóstico por imagen , Neoplasias de los Genitales Femeninos/diagnóstico por imagen , Ovario/diagnóstico por imagen , Enfermedades de los Anexos/diagnóstico por imagen , Adulto , Femenino , Humanos , Persona de Mediana Edad , Neoplasias Ováricas/diagnóstico por imagen , Radiología/métodos , Radiología/normas , Reproducibilidad de los Resultados , Proyectos de Investigación/normas , Estudios Retrospectivos , Ultrasonografía/métodos , Ultrasonografía/normas
15.
J Orthop Surg Res ; 16(1): 304, 2021 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-33964938

RESUMEN

BACKGROUND: This systematic review was conducted to gather available evidence on the effectiveness of muscle pedicle bone flap transplantation in adult patients with femoral neck fractures. METHODS: Databases such as PubMed, EMBASE, IEEE, Web of Science, and Cochrane library were searched from their dates of inception until March 2021. Two reviewers independently selected the interventional studies on the assessment of the effectiveness of muscle pedicle bone flap transplantation for femoral neck fractures; data extraction and assessment of the methodological quality as per the Institute of Health Economics quality appraisal checklist were also performed by the reviewers. The effectiveness and complication outcomes were assessed by calculating the average rates. RESULTS: Overall, 20 studies with 1022 patients were included in this review. Notably, the methodologic quality of the included studies was typically poor. The average effective rates were as follows: good, 73.4%; fair, 15.4%; and poor, 10.9%. Moreover, the average nonunion rate, average avascular necrosis rate, average collapse rate, and the overall reoperation rate were 9.0%, 6.7%, 4.7%, and 7.3%, respectively. CONCLUSIONS: This systematic review of heterogeneous studies with varying number of patients and varying surgical techniques indicated that muscle pedicle bone flap transplantation provides promising results with low rates of avascular necrosis and nonunion. Nevertheless, further controlled studies are required to ascertain the effectiveness of muscle pedicle bone flap transplantation in treating femoral neck fracture.


Asunto(s)
Huesos , Fracturas del Cuello Femoral/cirugía , Fijación Interna de Fracturas/métodos , Músculos , Colgajos Quirúrgicos/trasplante , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/prevención & control , Calidad de la Atención de Salud , Terapéutica , Resultado del Tratamiento , Adulto Joven
16.
Nano Lett ; 21(7): 3302-3309, 2021 04 14.
Artículo en Inglés | MEDLINE | ID: mdl-33792318

RESUMEN

Nanomeshes having ultrathin thicknesses and penetrating nanopores promise fast diffusion and precise selectivity and are highly desired in diffusion-involved processes such as separation. Herein, we report a liquid-phase two-dimensional (2D) assembly strategy to synthesize phenolic and carbonaceous nanomeshes with sub-10 nm pores and thicknesses. The synthesis is enabled simply by introducing glycerol in the thermopolymerization of resol/polyether micelles dispersed in ethanol. Experimental and simulation results reveal that glycerol's strong ability to form hydrogen bonds constrain the motion of the micelles, directing them to pack and merge exclusively in the lateral direction. Upon removal of polyether, we obtain phenolic nanomeshes with lateral sizes up to hundreds of micrometers, which can be further converted to carbonaceous nanomeshes. As a proof of concept, we use stacked phenolic and carbonaceous nanomeshes as separation membranes. They show superior permselectivity to nanosized solutes with permeance ∼2-110 times higher than that of other membranes.

17.
Angew Chem Int Ed Engl ; 60(13): 7397-7404, 2021 03 22.
Artículo en Inglés | MEDLINE | ID: mdl-33337566

RESUMEN

A broad-spectrum, catalytic method has been developed for the synthesis of sulfonamides and sulfamates. With the activation by the combination of a catalytic amount of 1-hydroxybenzotriazole (HOBt) and silicon additives, amidations of sulfonyl fluorides and fluorosulfates proceeded smoothly and excellent yields were generally obtained (87-99 %). Noticeably, this protocol is particularly efficient for sterically hindered substrates. Catalyst loading is generally low and only 0.02 mol % of catalyst is required for the multidecagram-scale synthesis of an amantadine derivative. In addition, the potential of this method in medicinal chemistry has been demonstrated by the synthesis of the marketed drug Fedratinib via a key intermediate sulfonyl fluoride 13. Since a large number of amines are commercially available, this route provides a facile entry to access Fedratinib analogues for biological screening.

18.
J Org Chem ; 85(22): 14785-14794, 2020 11 20.
Artículo en Inglés | MEDLINE | ID: mdl-32885966

RESUMEN

Annulations of ortho-phosphinoarenesulfonyl fluorides with trimethylsilyl azide were developed to access an unprecedented benzo-1,2,3-thiazaphosphole heterocycle. A corresponding reaction mechanism was proposed and further elucidated by experimental and computational studies. The reaction proceeds through a Staudinger-type iminophosphorane intermediate followed by intramolecular trapping with sulfonyl fluoride.

19.
Small ; 16(9): e1903879, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31599122

RESUMEN

Covalent triazine frameworks (CTFs) hosting arrays of highly ordered sub-2-nm pores are expected to exhibit unusual nanofluidic behaviors, which may enable important applications such as desalination. Herein, nonequilibrium molecular dynamics simulations are applied to investigate transport of water and ions inside two typical CTFs-CTF-1, and CTF-2-having intrinsic pores of 1.2 and 1.5 nm, respectively. Their monolayers exhibit extremely high water permeance but weak ion rejection. CTF multilayers are then investigated. Transport resistances composed of interior and interfacial contribution are correlated with stacking numbers of CTF monolayers to develop equations of predicting water permeance. It is revealed that both the stacking fashion and the number of CTF monolayers forming multilayers significantly influence permeation and ion rejection. Staggered multilayers exhibit much higher ion rejection than eclipsed ones. Staggered CTF-2 multilayers completely reject ions because the interlayer paths between two adjacent staggered monolayers allow only water molecules to pass through. Importantly, it is predicted from the equations that few-layered staggered CTF-2 multilayers, which can be relatively easily produced by experimental methods, exhibit 100% NaCl rejection and up to 100 times higher permeance than commercial reverse osmosis membranes, implying their great potential as building blocks to prepare next-generation desalination membranes.

20.
Phys Chem Chem Phys ; 21(48): 26591-26597, 2019 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-31789327

RESUMEN

Mixed matrix membranes (MMMs) have gained significant attention due to their high water permeability without the cost of salt rejection. However, the mechanism of water transport through MMMs is still controversial. Herein, a type of two-dimensional covalent organic framework (COF), TpPa-1, was selected as a blending additive for mixing with polyamide (PA) due to its good compatibility with polymeric matrices. We performed nonequilibrium molecular dynamics simulations to investigate the transport properties of the water molecules passing through MMMs. The permeance of MMMs was obviously enhanced compared to that of the pure PA membrane. However, this enhancement in permeance did not originate from the intrinsic pores of COFs. The PA atoms confined in the pores had extremely low diffusivity and thus, the water molecules were trapped inside the COF pores. Outside the COF pores, there was an interfacial region between COFs and PA, in which the water molecules aggregated to form a high-density region. In this region, the average flow velocities of the water molecules were much higher than those in pure PA or PA outside the mixed region of MMMs. The water transport mechanism discovered in this work offers an alternative and more likely explanation for the high permeance observed in PA/COF MMMs, and this understanding can be helpful to design more efficient MMMs.

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