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1.
Ann Oncol ; 35(7): 643-655, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38777726

RESUMEN

BACKGROUND: POLE and POLD1 proofreading deficiency (POLE/D1pd) define a rare subtype of ultramutated metastatic colorectal cancer (mCRC; over 100 mut/Mb). Disease-specific data about the activity and efficacy of immune checkpoint inhibitors (ICIs) in POLE/D1pd mCRC are lacking and it is unknown whether outcomes may be different from mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) mCRCs treated with ICIs. PATIENTS AND METHODS: In this global study, we collected 27 patients with mCRC harboring POLE/D1 mutations leading to proofreading deficiency and treated with anti-programmed cell death-ligand 1 alone +/- anti-cytotoxic T-lymphocyte antigen-4 agents. We collected clinicopathological and genomic characteristics, response, and survival outcomes after ICIs of POLE/D1pd mCRC and compared them with a cohort of 610 dMMR/MSI-H mCRC patients treated with ICIs. Further genomic analyses were carried out in an independent cohort of 7241 CRCs to define POLE and POLD1pd molecular profiles and mutational signatures. RESULTS: POLE/D1pd was associated with younger age, male sex, fewer RAS/BRAF driver mutations, and predominance of right-sided colon cancers. Patients with POLE/D1pd mCRC showed a significantly higher overall response rate (ORR) compared to dMMR/MSI-H mCRC (89% versus 54%; P = 0.01). After a median follow-up of 24.9 months (interquartile range: 11.3-43.0 months), patients with POLE/D1pd showed a significantly superior progression-free survival (PFS) compared to dMMR/MSI-H mCRC [hazard ratio (HR) = 0.24, 95% confidence interval (CI) 0.08-0.74, P = 0.01] and superior overall survival (OS) (HR = 0.38, 95% CI 0.12-1.18, P = 0.09). In multivariable analyses including the type of DNA repair defect, POLE/D1pd was associated with significantly improved PFS (HR = 0.17, 95% CI 0.04-0.69, P = 0.013) and OS (HR = 0.24, 95% CI 0.06-0.98, P = 0.047). Molecular profiling showed that POLE/D1pd tumors have higher tumor mutational burden (TMB). Responses were observed in both subtypes and were associated with the intensity of POLE/D1pd signature. CONCLUSIONS: Patients with POLE/D1pd mCRC showed more favorable outcomes compared to dMMR/MSI-H mCRC to treatment with ICIs in terms of tumor response and survival.


Asunto(s)
Neoplasias Colorrectales , ADN Polimerasa III , ADN Polimerasa II , Inhibidores de Puntos de Control Inmunológico , Mutación , Proteínas de Unión a Poli-ADP-Ribosa , Humanos , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Masculino , Femenino , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Persona de Mediana Edad , Anciano , ADN Polimerasa II/genética , Proteínas de Unión a Poli-ADP-Ribosa/genética , ADN Polimerasa III/genética , Adulto , Inestabilidad de Microsatélites , Anciano de 80 o más Años , Reparación de la Incompatibilidad de ADN
2.
Encephale ; 49(3): 211-218, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35331466

RESUMEN

OBJECTIVES: Behavior problems are one of the most common reasons for seeking mental health services in pediatric populations. The objectives are to evaluate the effects of the EQUIPE program (Étude Québécoise d'Intervention pour les Parents d'Enfants avec des problèmes de comportement) and to analyze the impact of the severity of behavior problems and of parental characteristics. METHODS: This program was translated from the Community Parent Education Program. The effects of EQUIPE, as compared to a control group, were evaluated by using Child Behavior Checklist and Parent Stress Index questionnaires before (T0) and after the intervention program (T1), and at 6 (T2) and 12months (T3) follow-up visits. RESULTS: In total, 533 participants were enrolled in intervention (n=465) (with "severe" or "mild" subgroups according to CBCL-T score) and a control group (n=68). In the two groups, the results showed a statistically significant decrease in Child Behavior Checklist and Parent Stress Index total scores at T1, T2 and T3, with the exception of Child Behavior Checklist total scores in the control group at T2. In the intervention group Child Behavior Checklist total scores were significantly higher in the "severe"; which was not the case for Parent Stress Index total scores at T2 and T3. DISCUSSION: Socioeconomic characteristics, family details, parental medical history and the age of the children appeared to influence changes in Child Behavior Checklist and Parent Stress Index total scores. CONCLUSION: The EQUIPE program is an effective intervention for reducing behavior problems and parents' stress in a French-Canadian population.


Asunto(s)
Servicios de Salud Mental , Padres , Humanos , Niño , Canadá , Padres/psicología , Relaciones Madre-Hijo , Conducta Infantil/psicología
3.
Prog Urol ; 32(16): 1455-1461, 2022 Dec.
Artículo en Francés | MEDLINE | ID: mdl-36088200

RESUMEN

OBJECTIVES: To assess the morbidity specific of extended pelvic lymphadenectomy during robot-assisted laparoscopic radical prostatectomy in a 8 year retrospective study. MATERIAL: We carried out a single-center, single-surgeon retrospective study on 342 consecutive patients who underwent a robot-assisted laparoscopic radical prostatectomy and extended pelvic lymphadenectomy, from July 2010 to March 2018. Postoperative complications were recorded up to 3 months after the operation. RESULTS: Thirty (8.8%) patients had at least one complication related to lymphadenectomy including 1 vascular injury (0.3%), 7 injuries of the obturator nerve (2%), 5 venous thromboembolic complications (1.5%) including 4 pulmonary embolisms, 10 symptomatic lymphoceles (2.9%) and 8 lymphoedemas (2.3%). Of these complications, 13 were classified Clavien 1 (43.3%), 8 Clavien 2 (26.7%), 7 Clavien 3a (23.3%) and 2 Clavien 3b (6.7%). In univariate analysis a high age (P=0.04), high BMI (P<0.01) and pT stage (P=0.02) were significantly associated with complication whereas in multivariate analysis, only age (P=0.02) and BMI (P<0.01) lived were. In univariate analysis high BMI (P=0.04) and lymph node involvement (P=0.04) were associated with lymphatic complication. We did not find any other specific risk factor for the other complications. CONCLUSION: With 8.8% of overall complications related to lymphadenectomy and 5% of complication classified Clavien grade 2 or higher, extended pelvic lymphadenectomy was not very morbid. Age and BMI were risk factors for a overall complication. BMI and lymph node involvement were risk factors for lymphatic complications. LEVEL OF PROOF: 4.


Asunto(s)
Laparoscopía , Linfocele , Neoplasias de la Próstata , Robótica , Masculino , Humanos , Próstata/patología , Estudios Retrospectivos , Prostatectomía/efectos adversos , Escisión del Ganglio Linfático/efectos adversos , Neoplasias de la Próstata/patología , Linfocele/epidemiología , Linfocele/etiología , Laparoscopía/efectos adversos , Pelvis/patología , Morbilidad
5.
Biochem Biophys Res Commun ; 569: 23-28, 2021 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-34216994

RESUMEN

Intravenous injections of human hematopoietic stem cells (hHSCs) is routinely used in clinic and for modeling hematopoiesis in mice. However, unspecific dilution in vascular system and non-hematopoietic organs challenges engraftment efficiency. Although spleen is capable of extra medullar hematopoiesis, its ability to support human HSC transplantation has never been evaluated. We demonstrate that intra-splenic injection results in high and sustained engraftment of hHSCs into immune-deficient mice, with higher chimerisms than with intravenous or intra-femoral injections. Our results support that spleen microenvironment provides a niche for HSCs amplification and offers a new route for efficient HSC transplantation.


Asunto(s)
Supervivencia de Injerto/fisiología , Trasplante de Células Madre Hematopoyéticas/métodos , Células Madre Hematopoyéticas/citología , Bazo/citología , Animales , Antígenos CD34/metabolismo , Femenino , Citometría de Flujo/métodos , Hematopoyesis/fisiología , Células Madre Hematopoyéticas/metabolismo , Humanos , Inyecciones , Luciferasas/genética , Luciferasas/metabolismo , Mediciones Luminiscentes/métodos , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Bazo/metabolismo , Quimera por Trasplante , Trasplante Heterólogo
7.
Rev Sci Instrum ; 91(12): 123102, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-33379964

RESUMEN

This work describes the correction method applied to the dataset acquired at the asteroid (4) Vesta by the visible channel of the visible and infrared mapping spectrometer. The rising detector temperature during data acquisitions in the visible wavelengths leads to a spectral slope increase over the whole spectral range. This limits the accuracy of the studies of the Vesta surface in this wavelength range. Here, we detail an empirical method to correct for the visible detector temperature dependency while taking into account the specificity of the Vesta dataset.

8.
Eur Phys J E Soft Matter ; 42(7): 86, 2019 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-31289962

RESUMEN

This paper describes the European Space Agency (ESA) experiments devoted to study thermodiffusion of fluid mixtures in microgravity environment, where sedimentation and convection do not affect the mass flow induced by the Soret effect. First, the experiments performed on binary mixtures in the IVIDIL and GRADFLEX experiments are described. Then, further experiments on ternary mixtures and complex fluids performed in DCMIX and planned to be performed in the context of the NEUF-DIX project are presented. Finally, multi-component mixtures studied in the SCCO project are detailed.

9.
Br J Surg ; 106(9): 1237-1247, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31183866

RESUMEN

BACKGROUND: BRAF mutation is associated with a poor prognosis in patients with metastatic colorectal cancer. For patients with resectable colorectal liver metastases (CRLMs), the prognostic impact of BRAF mutation is unknown and the benefit of surgery debated. This nationwide intergroup (ACHBT, FRENCH, AGEO) study aimed to evaluate the oncological outcome of patients undergoing liver resection for BRAF-mutated CRLMs. METHODS: The study included patients who underwent resection for BRAF-mutated CRLMs in 24 centres between 2012 and 2016. A case-matched comparison was made with 183 patients who underwent resection of CRLMs with wild-type BRAF during the same interval. RESULTS: Sixty-six patients who underwent resection for BRAF-mutated CRLMs in 24 centres were compared with 183 patients with wild-type BRAF. The 1- and 3-year disease-free survival (DFS) rates were 46 and 19 per cent for the BRAF-mutated group, and 55·4 and 27·8 per cent for the group with wild-type BRAF (P = 0·430). In multivariable analysis, BRAF mutation was not associated with worse DFS (hazard ratio 1·16, 95 per cent c.i. 0·72 to 1·85; P = 0·547). The 1- and 3-year overall survival rates after surgery were 94 and 54 per cent respectively among patients with BRAF mutation, and 95·8 and 82·9 per cent in those with wild-type BRAF (P = 0·004). Median survival after disease progression was 23·0 (95 per cent c.i. 11·0 to 35·0) months among patients with mutated BRAF and 44·3 (35·9 to 52·6) months in those with wild-type BRAF (P = 0·050). Multisite disease progression was more common in the BRAF-mutated group (48 versus 29·8 per cent; P = 0·034). CONCLUSION: These results support surgical treatment for resectable BRAF-mutated CRLM, as BRAF mutation by itself does not increase the risk of relapse after resection. BRAF mutation is associated with worse survival in patients whose disease relapses after resection of CRLM, as for non-metastatic colorectal cancer.


Asunto(s)
Neoplasias Colorrectales/genética , Neoplasias Hepáticas/secundario , Recurrencia Local de Neoplasia/genética , Proteínas Proto-Oncogénicas B-raf/genética , Anciano , Estudios de Casos y Controles , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/cirugía , Supervivencia sin Enfermedad , Femenino , Hepatectomía , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/cirugía , Masculino , Persona de Mediana Edad , Mutación/genética , Análisis de Supervivencia
10.
Rev Sci Instrum ; 90(12): 123110, 2019 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-31893819

RESUMEN

Data acquired at Ceres by the visible channel of the Visible and InfraRed mapping spectrometer (VIR) on board the NASA Dawn spacecraft are affected by the temperatures of both the visible (VIS) and the infrared (IR) sensors, which are, respectively, a charged coupled device and a HgCdTe array. The variations of the visible channel temperatures measured during the sessions of acquisitions are correlated with the variations in the spectral slope and shape for all the mission phases. The IR channel temperature is more stable during the acquisitions; nonetheless, it is characterized by a bimodal distribution whether the cryocooler (and, therefore, the IR channel) is used or not during the visible channel operations. When the infrared channel temperature is high (175 K, i.e., not in use and with the cryocooler off), an additional negative slope and a distortion are observed in the spectra of the visible channel. We developed an empirical correction based on a reference spectrum for the whole dataset; it is designed to correct the two issues related to the sensor temperatures that we have identified. The reference spectrum is calculated to be representative of the global Ceres' surface. It is also made of the data acquired when the visible and infrared channel temperatures are equal to the ones measured during an observation of the Arcturus star by VIR, which is consistent with several ground-based observations. The developed correction allows reliable analysis and mapping to be performed by minimizing the artifacts induced by fluctuations of the VIS temperature. Thanks to this correction, a direct comparison between different mission phases during which the VIR experienced different visible and infrared channel temperatures is now possible.

11.
Clin Transl Radiat Oncol ; 10: 13-22, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29928701

RESUMEN

An estimated 990,000 new cases of gastric cancer are diagnosed worldwide each year. Surgical excision, the only chance for prolonged survival, is feasible in about 20% of cases. Even after surgery, the median survival is limited to 12 to 20 months due to the frequency of locoregional and/or metastatic recurrences. This led to clinical trials associating surgery with neoadjuvant or adjuvant treatments to improve tumor control and patient survival. The most studied modalities are perioperative chemotherapy and adjuvant chemoradiotherapy. To date, evidence has shown a survival benefit for postoperative chemoradiotherapy and for perioperative chemotherapy. Phase III trials are ongoing to compare these two modalities. The aim of this review is to synthesize current knowledge about adjuvant chemoradiotherapy in the management of gastric adenocarcinoma, and to consider its prospects by integrating modern radiotherapy techniques.

12.
J Chem Phys ; 148(18): 184702, 2018 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-29764126

RESUMEN

An artificial oil-in-water emulsion analogous to those found in bioresources or food matrices is simulated and studied experimentally. It is composed of one of the major natural free fatty acids (the oleic acid, OA) and the corresponding triacylglyceride (trioleic glyceride, or triolein, GTO). Because of the large time and length scales involved, the molecular simulations are done with the Martini force field, a coarse-grained model. This allowed us to study the water-OA-GTO system at different compositions with more than 20 000 molecules and up to 2 µs. Interfacial tension was measured using the pendant drop method and compared with molecular simulation results. We observe very good agreement at high OA concentrations and deviations up to 15% at low OA concentrations. The water solubility in the lipid phase is in fair agreement with experiments, between 0.03 and 0.32 mol/l, rising with the OA content. The area occupied by OA and GTO at the interface between water and the pure product fitted with experimental data (AOA = 36.6 Å2 and AGTO = 152.1 Å2). The consistency between simulation and experimental results allowed a structural analysis of the interface. A bilayer structure of the lipids at the water/oil interface is proposed, containing preferentially oleic acid but also triolein. Through all these results, the usefulness of coarse-grained simulation for the description of water-oil interfacial organization is demonstrated. This method will be used later to bring local information on the organization of target compounds, necessary in biomass fractionation processes or food additive formulations, for example.

13.
Rev Med Interne ; 39(6): 393-399, 2018 Jun.
Artículo en Francés | MEDLINE | ID: mdl-29716754

RESUMEN

BACKGROUND: Medication reconciliation (MR) is a systematic and comprehensive review of all medication a patient is taking. In this study, a discharge medication sheet (DMS) is given to patients upon discharge: it contains discharge prescription and any changes made to admission prescription with justifications. The aim of this study is to explore general practitioners' (GP) perceptions of this DMS in order to suggest improvements. METHODS: In this prospective observational study, individual semi-directed interviews were conducted with GPs who received a DMS following the hospitalization of one of their patients. Answers were grouped by topic and subjected to descriptive analysis. RESULTS: Between October 2015 and July 2016, 33 DMS were completed. Among the 33 GPs, 16 had seen their patients with their DMS and agreed to be interviewed. The DMS was very appreciated and improved care pathway. However, this study highlights transmission difficulties for this sheet, attributed in particular to a lack of information of practitioners and patients and to the paper format, which appears to be inadequate. The main suggested improvement is real-time transmission of the DMS via email. CONCLUSION: Practitioners' opinion is in favor of the use of a DMS. Certain specific points need to be improved, such as better information of practitioners and patients, and transmission of the DMS via a secure email system.


Asunto(s)
Actitud del Personal de Salud , Continuidad de la Atención al Paciente/organización & administración , Médicos Generales , Conciliación de Medicamentos/métodos , Alta del Paciente , Adulto , Anciano , Continuidad de la Atención al Paciente/normas , Femenino , Médicos Generales/psicología , Médicos Generales/estadística & datos numéricos , Humanos , Masculino , Conciliación de Medicamentos/organización & administración , Conciliación de Medicamentos/estadística & datos numéricos , Persona de Mediana Edad , Alta del Paciente/normas , Alta del Paciente/estadística & datos numéricos , Percepción , Pautas de la Práctica en Medicina/estadística & datos numéricos
14.
Oncogene ; 35(43): 5619-5628, 2016 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-27157616

RESUMEN

Gastric carcinoma is the third leading cause of cancer-related death worldwide. This cancer, most of the time metastatic, is essentially treated by surgery associated with conventional chemotherapy, and has a poor prognosis. The existence of cancer stem cells (CSC) expressing CD44 and a high aldehyde dehydrogenase (ALDH) activity has recently been demonstrated in gastric carcinoma and has opened new perspectives to develop targeted therapy. In this study, we evaluated the effects of all-trans-retinoic acid (ATRA) on CSCs in human gastric carcinoma. ATRA effects were evaluated on the proliferation and tumorigenic properties of gastric carcinoma cells from patient-derived tumors and cell lines in conventional 2D cultures, in 3D culture systems (tumorsphere assay) and in mouse xenograft models. ATRA inhibited both tumorspheres initiation and growth in vitro, which was associated with a cell-cycle arrest through the upregulation of cyclin-dependent kinase (CDK) inhibitors and the downregulation of cell-cycle progression activators. More importantly, ATRA downregulated the expression of the CSC markers CD44 and ALDH as well as stemness genes such as Klf4 and Sox2 and induced differentiation of tumorspheres. Finally, 2 weeks of daily ATRA treatment were sufficient to inhibit gastric tumor progression in vivo, which was associated with a decrease in CD44, ALDH1, Ki67 and PCNA expression in the remaining tumor cells. Administration of ATRA appears to be a potent strategy to efficiently inhibit tumor growth and more importantly to target gastric CSCs in both intestinal and diffuse types of gastric carcinoma.


Asunto(s)
Antineoplásicos/farmacología , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patología , Tretinoina/farmacología , Aldehído Deshidrogenasa/metabolismo , Animales , Biomarcadores , Puntos de Control del Ciclo Celular/efectos de los fármacos , Puntos de Control del Ciclo Celular/genética , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Femenino , Humanos , Receptores de Hialuranos/metabolismo , Inmunofenotipificación , Factor 4 Similar a Kruppel , Ratones , Esferoides Celulares , Neoplasias Gástricas/tratamiento farmacológico , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto
18.
Br J Cancer ; 113(9): 1313-22, 2015 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-26528707

RESUMEN

BACKGROUND: Bone metastases (BMs) are associated with poor outcome in metastatic clear-cell renal carcinoma (m-ccRCC) treated with anti-vascular endothelial growth factor tyrosine kinase inhibitors (anti-VEGFR-TKIs). We aimed to investigate whether expression in the primary tumour of genes involved in the development of BM is associated with outcome in m-ccRCC patients treated with anti-VEGFR-TKIs. METHODS: Metastatic clear-cell renal cell carcinoma patients with available fresh-frozen tumour and treated with anti-VEGFR-TKIs. Quantitative real-time PCR (qRT-PCR) for receptor activator of NF-kB (RANK), RANK-ligand (RANKL), osteoprotegerin (OPG), the proto-oncogene SRC and DKK1 (Dickkopf WNT signalling pathway inhibitor-1). Time-to-event analysis by Kaplan-Meier estimates and Cox regression. RESULTS: We included 129 m-ccRCC patients treated between 2005 and 2013. An elevated RANK/OPG ratio was associated with shorter median time to metastasis (HR 0.50 (95% CI 0.29-0.87); P=0.014), shorter time to BM (HR 0.54 (95% CI 0.31-0.97); P=0.037), shorter median overall survival (mOS) since initial diagnosis (HR 2.27 (95% CI 1.44-3.60); P=0.0001), shorter median progression-free survival (HR 0.44 (95% CI 0.28-0.71); P=0.001) and mOS (HR 0.31 (95% CI 0.19-0.52); P<0.0001) on first-line anti-VEGFR-TKIs in the metastatic setting. Higher RANK expression was associated with shorter mOS on first-line anti-VEGFR-TKIs (HR 0.46 (95% CI 0.29-0.73); P=0.001). CONCLUSIONS: RANK/OPG ratio of expression in primary ccRCC is associated with BM and prognosis in patients treated with anti-VEGFR-TKIs. Prospective validation is warranted.


Asunto(s)
Neoplasias Óseas/patología , Carcinoma de Células Renales/genética , Neoplasias Renales/genética , Osteoprotegerina/genética , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Receptor Activador del Factor Nuclear kappa-B/genética , Receptores de Factores de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Neoplasias Óseas/genética , Carcinoma de Células Renales/tratamiento farmacológico , Carcinoma de Células Renales/patología , Supervivencia sin Enfermedad , Femenino , Genes src/genética , Humanos , Péptidos y Proteínas de Señalización Intercelular/genética , Neoplasias Renales/tratamiento farmacológico , Neoplasias Renales/patología , Masculino , Persona de Mediana Edad , Pronóstico , Inhibidores de Proteínas Quinasas/uso terapéutico , Proto-Oncogenes Mas , Ligando RANK/genética , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética
19.
Chem Commun (Camb) ; 51(57): 11482-4, 2015 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-26091539

RESUMEN

Recombinant proteins bearing a tag are crucial tools for assessing protein location or function. Small tags such as Cys4 tag (tetracysteine; Cys-Cys-X-X-Cys-Cys) are less likely disrupt protein function in the living cell than green fluorescent protein. Herein we report the first example of the design and synthesis of a dual fluorescence and hyperpolarized (129)Xe NMR-based sensor of Cys4-tagged proteins. This sensor becomes fluorescent when bound to such Cys4-tagged peptides, and the (129)Xe NMR spectrum exhibits a specific signal, characteristic of the biosensor-peptide association.


Asunto(s)
Cisteína/análisis , Fluoresceínas/química , Colorantes Fluorescentes/química , Compuestos Organometálicos/química , Péptidos/análisis , Compuestos Policíclicos/química , Secuencia de Aminoácidos , Técnicas Biosensibles , Datos de Secuencia Molecular , Resonancia Magnética Nuclear Biomolecular , Proteínas Recombinantes/análisis , Espectrometría de Fluorescencia , Isótopos de Xenón/química
20.
J Phys Chem A ; 119(1): 140-51, 2015 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-25479370

RESUMEN

A classical all-atoms force field for molecular simulations of hydrofluorocarbons (HFCs) has been developed. Lennard-Jones force centers plus point charges are used to represent dispersion-repulsion and electrostatic interactions. Parametrization of this force field has been performed iteratively using three target properties of pentafluorobutane: the quantum energy of an isolated molecule, the dielectric constant in the liquid phase, and the compressed liquid density. The accuracy and transferability of this new force field has been demonstrated through the simulation of different thermophysical properties of several fluorinated compounds, showing significant improvements compared to existing models. This new force field has been applied to study solubilities of several gases in poly(vinylidene fluoride) (PVDF) above the melting temperature of this polymer. The solubility of CH4, CO2, H2S, H2, N2, O2, and H2O at infinite dilution has been computed using test particle insertions in the course of a NpT hybrid Monte Carlo simulation. For CH4, CO2, and their mixtures, some calculations beyond the Henry regime have also been performed using hybrid Monte Carlo simulations in the osmotic ensemble, allowing both swelling and solubility determination. An ideal mixing behavior is observed, with identical solubility coefficients in the mixtures and in pure gas systems.

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