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1.
Small ; : e2400965, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38506595

RESUMEN

Nanostructured metal hydrides with unique morphology and improved hydrogen storage properties have attracted intense interests. However, the study of the growth process of highly active borohydrides remains challenging. Herein, for the first time the synthesis of LiBH4 nanorods through a hydrogen-assisted one-pot solvothermal reaction is reported. Reaction of n-butyl lithium with triethylamine borane in n-hexane under 50 bar of H2 at 40-100 °C gives rise to the formation of the [100]-oriented LiBH4 nanorods with 500-800 nm in diameter, whose growth is driven by orientated attachment and ligand adsorption. The unique morphology enables the LiBH4 nanorods to release hydrogen from ≈184 °C, 94 °C lower than the commercial sample (≈278 °C). Hydrogen release amounts to 13 wt% within 40 min at 450 °C with a stable cyclability, remarkably superior to the commercial LiBH4 (≈9.1 wt%). More importantly, up to 180 °C reduction in the onset temperature of hydrogenation is successfully attained by the nanorod sample with respect to the commercial counterpart. The LiBH4 nanorods show no foaming during dehydrogenation, which improves the hydrogen cycling performance. The new approach will shed light on the preparation of nanostructured metal borohydrides as advanced functional materials.

2.
Nano Lett ; 23(11): 4699-4707, 2023 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-36951377

RESUMEN

Mass transfer is critical in catalytic processes, especially when the reactions are facilitated by nanostructured catalysts. Strong efforts have been devoted to improving the efficacy and quantity of active sites, but often, mass transfer has not been well studied. Herein, we demonstrate the importance of mass transfer in the electrocatalytic oxygen reduction reaction (ORR) by tailoring the pore sizes. Using a confined-etching strategy, we fabricate boron- and nitrogen-doped carbon (B,N@C) electrocatalysts featuring abundant active sites but different porous structures. The ORR performance of these catalysts is found to correlate with diffusion of the reactant. The optimized B,N@C with trimodal-porous structures feature enhanced O2 diffusion and better activity per heteroatomic site toward the ORR process. This work demonstrates the significance of the nanoarchitecture engineering of catalysts and sheds light on how to optimize structures featuring abundant active sites and enhanced mass transfer.

3.
J Intern Med ; 293(4): 494-507, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36682032

RESUMEN

OBJECTIVE: To explore the role of peripheral lymphocyte count in phenotyping and prognosis prediction in dermatomyositis (DM) patients with anti-MDA5 antibodies. METHODS: In total, 1669 patients with idiopathic inflammatory myopathy (IIM) were retrospectively enrolled. Clinical characteristics and prognosis of patients with anti-MDA5+ DM were analyzed in association with peripheral lymphocyte counts and clusters determined by unsupervised machine learning. RESULTS: The peripheral lymphocyte count was significantly lower in the anti-MDA5+ DM group (N = 421) than in the other IIM serotype groups. The anti-MDA5+ DM patients were divided into three groups; the severe lymphopenia group had skin ulcers and rapidly progressive interstitial lung disease (RP-ILD); patients with a normal lymphocyte count had a younger age of onset, more frequent arthritis, and normal serum ferritin levels, whereas mild lymphopenia group showed a moderate increase of serum ferritin and intermediate incidence of RP-ILD. Survival analysis revealed that the 3- and 6-month mortality rates were significantly higher in the severe lymphopenia group (29.0% and 42.1%, respectively) than in the mild lymphopenia group and normal lymphocyte count group (p value <0.001). Consistently, unsupervised machine learning identified three similar groups; the arthritis cluster shows the highest lymphocyte counts and best prognosis; the RP-ILD cluster presents the lowest peripheral lymphocyte, high incidence of RP-ILD, and poor prognosis; the typical DM rash cluster had a moderate peripheral lymphocyte count and an intermediate prognosis. CONCLUSIONS: Lymphopenia is a unique manifestation of anti-MDA5+ DM. Peripheral lymphocyte count can define clinical phenotypes and predict prognosis in anti-MDA5+ DM.


Asunto(s)
Dermatomiositis , Enfermedades Pulmonares Intersticiales , Linfopenia , Humanos , Dermatomiositis/complicaciones , Dermatomiositis/diagnóstico , Progresión de la Enfermedad , Estudios Retrospectivos , Enfermedades Pulmonares Intersticiales/complicaciones , Enfermedades Pulmonares Intersticiales/diagnóstico , Helicasa Inducida por Interferón IFIH1 , Autoanticuerpos , Pronóstico , Fenotipo , Recuento de Linfocitos , Linfocitos , Ferritinas
4.
Small ; : e2305117, 2023 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-37963822

RESUMEN

The icosahedral closo dodecaborate cluster [B12 H12 ]2- is gaining increasing interest due to its unique properties including the ease of functionalization, 3D aromaticity, and formation of metal salts with high ion conductivity. In this work, simple and effective preparation of silver closo dodecaborte (Ag2 B12 H12 ) films is reported by an electrochemical route. The size of the Ag2 B12 H12 particles in the films can be tuned from nanometers to micrometers by varying the electrochemical parameters. Ag nanoclusters with controllable sizes are successfully generated via electrochemical reduction reactions or thermal anneal of the Ag2 B12 H12 films. When tested for hydrogen evolution reaction (HER) in an acidic solution, the as-prepared Ag nanoparticles deliver a current density of 10 mA cm-2 at 376 mV overpotential. This research sheds light on a new synthesis of [B12 H12 ]2- based thin films, the generation of metal nano-powders, and their application in HER or other applications.

5.
J Am Chem Soc ; 144(19): 8434-8438, 2022 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-35446021

RESUMEN

BN/CC isosterism has been widely investigated as a strategy to expand carbon-based compounds. The introduction of BN units in organic molecules always results in novel properties. In this work, we reported the first synthesis and characterization of 1,6;2,3-bis-BN cyclohexane, an isostere of cyclohexane with two adjacent BN pairs. Its ring flipping barrier is similar to that of cyclohexane. Protic hydrogens on N in 1,6;2,3-bis-BN cyclohexane show higher reactivity than its isomeric bis-BN cyclohexane. This compound exhibits an appealing hydrogen storage capability of >9.0 wt %, nearly twice as much as the 1,2;4,5-bis-BN cyclohexane.


Asunto(s)
Ciclohexanos , Hidrógeno
6.
Eur Radiol ; 32(7): 4699-4706, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35267089

RESUMEN

OBJECTIVES: To evaluate the efficacy and safety of marking ground glass nodules (GGNs) with pulmonary nodules localization needle (PNLN) prior to video-assisted thoracoscopic surgery (VATS). MATERIALS AND METHODS: From June 2020 to February 2021, all patients with GGNs who received CT-guided localization using PNLN before VATS were enrolled. Clinical and imaging data were retrospectively analyzed. RESULTS: A total of 352 consecutive patients with 395 GGNs were included in the study. The mean diameter of GGNs was 0.95 ± 0.48 cm, and the shortest distance from nodules to the pleura was 1.73 ± 0.96 cm. All 395 GGNs were marked using PNLNs. The time required for marking was 7.8 ± 2.2 min. The marking success rate was 99.0% (391/395). The marking failure of four nodules was all due to the unsatisfactory position of PNLNs. No marker dislocation occurred. Marking-related complications included pneumothorax in 63 cases (17.9%), hemorrhage in 34 cases (9.7%), and hemoptysis in 6 cases (1.7%). All the complications were minor and did not need special treatment. Localization and VATS were performed on the same day in 95 cases and on different days in 257 cases. All GGNs were successfully removed by VATS. No patient converted to thoracotomy. Histopathological examination revealed 74 (18.7%) benign nodules and 321 (81.3%) malignant nodules. CONCLUSIONS: It is safe and reliable to perform preoperative localization of GGNs using PNLNs, which can effectively guide VATS to remove GGNs. KEY POINTS: • Preoperative localization of GGNs could effectively guide VATS to remove GGNs. • PNLN was based on the marking principle of hook-wire, through the improvement of its material, specially designed to mark pulmonary nodules. • The application of PNLN to mark GGNs had high success rate, good patient tolerance, and no dislocation. Meanwhile, VATS could be performed 2 to 3 days after marking GGNs with PNLN.


Asunto(s)
Neoplasias Pulmonares , Nódulos Pulmonares Múltiples , Nódulo Pulmonar Solitario , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/cirugía , Nódulos Pulmonares Múltiples/diagnóstico por imagen , Nódulos Pulmonares Múltiples/cirugía , Estudios Retrospectivos , Nódulo Pulmonar Solitario/diagnóstico por imagen , Nódulo Pulmonar Solitario/cirugía , Cirugía Torácica Asistida por Video/métodos
7.
BMC Pulm Med ; 22(1): 311, 2022 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-35964027

RESUMEN

OBJECTIVE: The purpose of this study was to evaluate the usefulness of intraprocedural CT and prior PET/CT fusion imaging in improving the diagnostic yield of CT-guided transthoracic core-needle biopsy (CNB) in lung masses. METHODS: In total, 145 subjects with lung masses suspicious for malignancy underwent image-guided transthoracic CNB. According to imaging modality the subjects were divided into two groups. PET/CT images obtained no more than 14 days before the biopsy were integrated with intraprocedural CT images. The integrated or fused images were then used to plan the puncture sites. The clinical characteristics, diagnostic yield of CNB, diagnostic accuracy rate, procedure-related complications and procedure duration were recorded and compared between the two groups. Final clinical diagnosis was determined by surgical pathology or at least 6-months follow-up. The diagnostic accuracy of CNB was obtained by comparing with final clinical diagnosis. RESULTS: 145 subjects underwent CNB with adequate samples, including 76 in fusion imaging group and 69 in routine group. The overall diagnostic yield and diagnostic accuracy rate were 80.3% (53/66), 82.9% (63/76) for fusion imaging group, 70.7% (41/58), 75.4% (52/69) for routine group, respectively. In addition, the diagnostic yield for malignancy in fusion imaging group (98.1%, 52/53) was higher than that in routine group (81.3%, 39/48). No serious procedure-related complications occurred in both two groups. CONCLUSION: CNB with prior PET/CT fusion imaging is particularly helpful in improving diagnostic yield and accurate rate of biopsy in lung masses, especially in heterogeneous ones, thus providing greater potential benefit for patients.


Asunto(s)
Biopsia Guiada por Imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones , Biopsia con Aguja Gruesa , Humanos , Biopsia Guiada por Imagen/métodos , Pulmón/diagnóstico por imagen , Pulmón/patología , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Tomografía Computarizada por Rayos X/métodos
8.
Chemistry ; 27(35): 9087-9093, 2021 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-33876844

RESUMEN

A significant obstacle in the large-scale applications of sodium borohydride (NaBH4 ) for hydrogen storage is its high cost. Herein, we report a new method to synthesize NaBH4 by ball milling hydrated sodium tetraborate (Na2 B4 O7 ⋅ 10H2 O) with low-cost Al or Al88 Si12 , instead of Na, Mg or Ca. An effective strategy is developed to facilitate mass transfer during the reaction by introducing NaH to enable the formation of NaAlO2 instead of dense Al2 O3 on Al surface, and by using Si as a milling additive to prevent agglomeration and also break up passivation layers. Another advantage of this process is that hydrogen in Na2 B4 O7 ⋅ 10H2 O serves as a hydrogen source for NaBH4 generation. Considering the low cost of the starting materials and simplicity in operation, our studies demonstrate the potential of producing NaBH4 in a more economical way than the commercial process.

9.
BMC Pulm Med ; 21(1): 39, 2021 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-33494732

RESUMEN

BACKGROUND: To evaluate the feasibility and safety of microcoil in simultaneous localization for multiple pulmonary nodules before video-assisted thoracic surgery (VATS). METHODS: Twenty-eight consecutive patients (26 two-nodule, 2 three-nodule; 58 nodules in total; Group A) underwent simultaneous CT-guided localization of multiple pulmonary nodules before VATS using microcoil. Successful targeting, localization, and VATS were defined as implantation of microcoil at the target site on CT image which was obtained immediately after the marking procedure, visualization of nodule location, and complete resection of the target nodule with adequate margin, respectively. Meanwhile, the clinical characteristics, localization procedure-related variables of the nodules and procedure-related complications in group A were also assessed and compared with those in a control group (221 single-localization procedures in 221 patients; Group B). RESULTS: Similar rates of successful targeting, localization and VATS were observed in group A and B (96.6% vs. 98.2%; 91.4% vs. 91.0%; 100% vs. 99.1%). Although the rate of overall complications (including localized pneumothorax and intrapulmonary hemorrhage) was a bit higher in group A than that in group B (32.8% vs. 30.8%, p = 0.771), only minor complications were observed in the subjects of the two groups with no need for further treatment. In addition, the duration of simultaneous localization procedures was significantly longer than that of single localization (24 ± 7.5 vs.13 ± 6 min, p < 0.001). CONCLUSIONS: CT-guided simultaneous microcoil localization for multiple pulmonary nodules before VATS was clinically feasible and safe with acceptable increase in the procedure time. Compared with localization for a single pulmonary nodule, simultaneous microcoil localizations for multiple nodules were prone to pneumothorax and hemorrhage. However, no statistically significant differences were observed between the two groups.


Asunto(s)
Neoplasias Pulmonares/cirugía , Nódulos Pulmonares Múltiples/cirugía , Periodo Preoperatorio , Cirugía Torácica Asistida por Video/efectos adversos , Tomografía Computarizada por Rayos X , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Nódulos Pulmonares Múltiples/diagnóstico por imagen , Nódulos Pulmonares Múltiples/patología , Neumotórax/etiología , Complicaciones Posoperatorias/etiología , Hemorragia Posoperatoria/etiología , Estudios Retrospectivos , Cirugía Torácica Asistida por Video/instrumentación
10.
Angew Chem Int Ed Engl ; 60(21): 11725-11729, 2021 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-33844369

RESUMEN

Amine-borane complexes have been extensively studied as hydrogen storage materials. Herein, we report a new amine-borane system featuring a reversible dehydrogenation and regeneration at room temperature. In addition to high purity H2 , the reaction between ethylenediamine bisborane (EDAB) and ethylenediamine (ED) leads to unique boron-carbon-nitrogen 5-membered rings in the dehydrogenation product where one boron is tricoordinated by three nitrogen atoms. Owing to the unique cyclic structure, the dehydrogenation product can be efficiently converted back to EDAB by NaBH4 and H2 O at room temperature. This finding could lead to the discovery of new amine boranes with potential usage as hydrogen storage materials.

11.
Eur Radiol ; 30(10): 5674-5683, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32458172

RESUMEN

OBJECTIVES: To summarize the experiences of CT-guided microcoil localization before video-assisted thoracoscopic surgery (VATS) and to investigate the risk factors associated with pleural marking failure. METHODS: Totally, 249 consecutive patients with 279 pulmonary nodules who underwent CT-guided microcoil localization prior to VATS were enrolled in this study. According to intraoperative observation, all the nodules were divided into two groups. The clinical characteristics and microcoil localization procedure-related variables of the nodules were analyzed by univariate analysis and multivariate logistic regression analysis to screen the independent factors associated with procedure results. RESULTS: Among the 279 nodules, 28 failed to observe the proximal end of the microcoil deployed on visceral pleura during VATS. The logistic regression revealed that needle-pleura angle (≤ 30°: OR = 39.022, p = 0.003), pleura-microcoil distance (≤ 10 mm: OR = 87.054, p < 0.001; 10~20 mm: OR = 10.088, p = 0.010), and presence of pleural indentation (OR = 21.623, p < 0.001) were independent risk factors for pleural marking failure. CONCLUSIONS: CT-guided microcoil localization for pulmonary nodules is a safe and effective procedure. Small needle-pleura angle (≤ 30°), pleura-microcoil distance (≤ 20 mm), and the presence of pleural indentation during the procedure are significant risk factors contributing to microcoil pleura marking failure. KEY POINTS: • CT-guided microcoil localization for pulmonary nodules was a safe and effective procedure. • CT-guided microcoil localization for pulmonary nodules yielded low complication rates. • Small needle-pleura angle, short pleura-microcoil distance, and the presence of pleural indentation were contributing to pleura marking failure.


Asunto(s)
Neoplasias Pulmonares/diagnóstico por imagen , Nódulos Pulmonares Múltiples/diagnóstico por imagen , Cuidados Preoperatorios , Radiografía Intervencional , Nódulo Pulmonar Solitario/diagnóstico por imagen , Cirugía Torácica Asistida por Video , Tomografía Computarizada por Rayos X , Adulto , Anciano , Femenino , Humanos , Neoplasias Pulmonares/cirugía , Masculino , Persona de Mediana Edad , Nódulos Pulmonares Múltiples/cirugía , Agujas , Pleura , Estudios Retrospectivos , Factores de Riesgo , Nódulo Pulmonar Solitario/cirugía
12.
J Phys Chem A ; 124(9): 1698-1704, 2020 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-32045237

RESUMEN

Ammonium aminodiboranate (AADB) and diammoniate of diborane (DADB) are two isomers of ammonia borane (AB), which have been intensively studied for hydrogen storage. Their high hydrogen contents give them the high potential to serve as hydrogen storage materials. To explore their dehydrogenation pathways, molecular dynamics (MD) simulations with a reactive force field (ReaxFF) were applied. Temperature ramping simulations of their thermolysis were carried out. For AADB, at low temperatures, its hydrogen release can be realized mainly via intermolecular dehydrogenations. As the temperature of the simulated system increases, the formations of B-N bonds begin to occur. In the case of DADB, we found that this molecule could release hydrogen at a lower temperature with the cleavage of the B-N bond. The compositional analysis of the simulated systems was also conducted to monitor the potential intermediates along their dehydrogenation pathways. Our current work provides a detailed picture of the initial dehydrogenation steps of AADB and DADB and highlights the difference in their respective dehydrogenation processes.

13.
Mediators Inflamm ; 2020: 7948095, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33192174

RESUMEN

OBJECTIVE: Soluble CD206 (sCD206) is considered a macrophage activation marker, and a previous study proved it as a potential biomarker to predict the severity of anti-melanoma differentiation-associated gene 5- (anti-MDA-5-) positive dermatomyositis- (DM-) associated interstitial lung disease (ILD). To investigate the role of sCD206 in various subtypes of DM, we evaluated the serum level of sCD206 in patients with different myositis-specific autoantibodies besides anti-MDA-5 and clarified its clinical significance. METHODS: Commercial enzyme-linked immunosorbent assay kits were used to detect serum concentrations of sCD206 in 150 patients with DM and 52 healthy controls (HCs). Correlations between sCD206 levels and clinical features, laboratory examinations, and pulmonary function test parameters were analysed. RESULTS: The median concentrations of serum sCD206 in DM patients were significantly higher than those in HCs (p < 0.0001). Furthermore, median sCD206 levels were elevated in patients with ILD (p = 0.001), especially in those with rapidly progressive ILD (RP-ILD) (p < 0.0001). In addition, sCD206 levels were negatively correlated with the pulmonary function test results, including the percent predicted forced vital capacity (r = -0.234, p = 0.023), percent predicted forced expiratory volume in one second (r = -0.225, p = 0.030), and percent predicted carbon monoxide diffusion capacity (r = -0.261, p = 0.014). Age- and gender-adjusted multivariable analysis showed that sCD206 was an independent prognostic factor for RP-ILD in patients with DM. A longitudinal study showed that sCD206 levels were positively correlated with the physician global assessment visual analog scale scores (ß = 54.201, p = 0.001). CONCLUSION: Serum sCD206 levels were significantly increased in patients with DM and significantly associated with RP-ILD, suggesting that sCD206 is an important biological predictor of RP-ILD in patients with DM.


Asunto(s)
Dermatomiositis/sangre , Enfermedades Pulmonares Intersticiales/sangre , Macrófagos/metabolismo , Glicoproteínas de Membrana/sangre , Receptores Inmunológicos/sangre , Adulto , Autoanticuerpos/sangre , Biomarcadores/metabolismo , Monóxido de Carbono/metabolismo , Estudios de Casos y Controles , Difusión , Progresión de la Enfermedad , Ensayo de Inmunoadsorción Enzimática , Femenino , Volumen Espiratorio Forzado , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Análisis Multivariante , Valor Predictivo de las Pruebas , Pronóstico , Curva ROC , Pruebas de Función Respiratoria , Estudios Retrospectivos , Riesgo
14.
Angew Chem Int Ed Engl ; 59(22): 8623-8629, 2020 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-32080947

RESUMEN

Sodium borohydride (NaBH4 ) is among the most studied hydrogen storage materials because it is able to deliver high-purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2 , forming Na2 B4 O7 ⋅10 H2 O and Na2 CO3 , both of which are ball-milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2 , bypasses the energy-intensive dehydration procedure to remove water from Na2 B4 O7 ⋅10 H2 O, and does not require high-pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.

15.
Angew Chem Int Ed Engl ; 59(23): 8800-8816, 2020 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-31625661

RESUMEN

Boron's unique position in the Periodic Table, that is, at the apex of the line separating metals and nonmetals, makes it highly versatile in chemical reactions and applications. Contemporary demand for renewable and clean energy as well as energy-efficient products has seen boron playing key roles in energy-related research, such as 1) activating and synthesizing energy-rich small molecules, 2) storing chemical and electrical energy, and 3) converting electrical energy into light. These applications are fundamentally associated with boron's unique characteristics, such as its electron-deficiency and the availability of an unoccupied p orbital, which allow the formation of a myriad of compounds with a wide range of chemical and physical properties. For example, boron's ability to achieve a full octet of electrons with four covalent bonds and a negative charge has led to the synthesis of a wide variety of borate anions of high chemical and electrochemical stability-in particular, weakly coordinating anions. This Review summarizes recent advances in the study of boron compounds for energy-related processes and applications.

16.
Chemistry ; 22(23): 7727-9, 2016 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-27017580

RESUMEN

Ammonium aminodiboranate ([NH4 ][BH3 NH2 BH3 ]) is a long-sought isomer of diammoniate of diborane ([NH3 BH2 NH3 ][BH4 ]) and ammonia borane (NH3 BH3 ) dimer. Our results show that [NH4 ][BH3 NH2 BH3 ] is stable in tetrahydrofuran at -18 °C and decomposes rapidly to NH3 BH2 NH2 BH3 and H2 at elevated temperatures. The decomposition pathway is dictated by the dihydrogen bonding between H(δ+) on NH4 (+) and H(δ-) on BH3 , as confirmed by theoretical calculations. This is in contrast to the interconversion between [NH3 BH2 NH3 ][BH4 ] and (NH3 BH3 )2 , although all three have dihydrogen bonds and the same stoichiometry.

17.
Inorg Chem ; 55(12): 5772-9, 2016 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-27227553

RESUMEN

Combined synchrotron and neutron powder diffraction indicates that A3V4(PO4)6 (A = Mg, Mn, Fe, Co, Ni) compounds crystallize with triclinic P1̅ symmetry. Lattice parameters expand as expected with successive increases in the ionic radius of the A(2+) ion. Cation disorder on the octahedral sites increases as the ionic radii of A(2+) ion decreases. Direct-current magnetic susceptibility measurements indicate that all compounds with magnetic A(2+) ions order anti-ferromagnetically with transition temperatures ranging from 12 to 15 K. Effective magnetic moments for A3V4(PO4)6 (A = Mg, Mn, Fe, Co, Ni) are 5.16, 11.04, 10.08, 9.76, and 7.96 µB per formula unit, respectively, in line with calculated values for high-spin transition metal ions. With the exception of Co3V4(PO4)6 the ultraviolet-visible spectra are dominated by d-d transitions of the V(3+) ions. The striking emerald green color of Co3V4(PO4)6 arises from the combined effects of d-d transitions involving both V(3+) and Co(2+).

18.
Chemistry ; 20(24): 7325-33, 2014 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-24788403

RESUMEN

Attempts to synthesize solvent-free MgB12H12 by heating various solvated forms (H2O, NH3, and CH3OH) of the salt failed because of the competition between desolvation and dehydrogenation. This competition has been studied by thermogravimetric analysis (TGA) and temperature-programmed desorption (TPD). Products were characterized by IR, solution- and solid-state NMR spectroscopy, elemental analysis, and single-crystal or powder X-ray diffraction analysis. For hydrated salts, thermal decomposition proceeded in three stages, loss of water to form first hexahydrated then trihydrated, and finally loss of water and hydrogen to form polyhydroxylated complexes. For partially ammoniated salts, two stages of thermal decomposition were observed as ammonia and hydrogen were released with weight loss first of 14 % and then 5.5 %. Thermal decomposition of methanolated salts proceeded through a single step with a total weight loss of 32 % with the release of methanol, methane, and hydrogen. All the gaseous products of thermal decomposition were characterized by using mass spectrometry. Residual solid materials were characterized by solid-state (11)B magic-angle spinning (MAS) NMR spectroscopy and X-ray powder diffraction analysis by which the molecular structures of hexahydrated and trihydrated complexes were solved. Both hydrogen and dihydrogen bonds were observed in structures of [Mg(H2O)6B12H12]⋅6 H2O and [Mg(CH3OH)6B12H12]⋅6 CH3OH, which were determined by single-crystal X-ray diffraction analysis. The structural factors influencing thermal decomposition behavior are identified and discussed. The dependence of dehydrogenation on the formation of dihydrogen bonds may be an important consideration in the design of solid-state hydrogen storage materials.

19.
Muscle Nerve ; 49(4): 610-4, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24218312

RESUMEN

INTRODUCTION: Entecavir, a nucleoside analog (NA), is effective for treatment of chronic hepatitis B virus (HBV) infection. METHODS: We report the case of a patient we encountered with entecavir-associated myopathy. We also performed a literature review of myopathies associated with nucleoside analogs. RESULTS: A 44-year-old man presented with a 3-month history of myalgia and progressive weakness. He had HBV infection and had received entecavir antiviral treatment for 5 years. Laboratory tests showed that serum creatine kinase levels were significantly elevated. Muscle histopathology showed abundant T-lymphocyte infiltration of muscle fibers, and HBV surface antigen and HBV core antigen were not present in muscle fibers. Entecavir-associated myopathy was subsequently diagnosed. The patient's symptoms eventually resolved, and serum CK levels decreased rapidly after he stopped receiving entecavir treatments. CONCLUSIONS: Patients who receive NA therapy should be closely monitored for myopathic side effects. Muscle Nerve 49:610-614, 2014.


Asunto(s)
Antivirales/efectos adversos , Guanina/análogos & derivados , Enfermedades Musculares/inducido químicamente , Enfermedades Musculares/diagnóstico , Adulto , Guanina/efectos adversos , Humanos , Masculino , Debilidad Muscular/inducido químicamente , Debilidad Muscular/diagnóstico
20.
Zhonghua Yi Xue Za Zhi ; 94(19): 1473-5, 2014 May 20.
Artículo en Zh | MEDLINE | ID: mdl-25143167

RESUMEN

OBJECTIVE: To describe the MRI features of Iliotibial band friction syndrome (ITBFS), in order to improve the understanding and diagnosis of ITBFS. METHODS: The MR findings of 16 patients (18 knees )of clinically diagnosis ITBFS were reviewed retrospectively. RESULTS: The MRI features of ITBFS:(1)Ill- defined abnormal signal intensity extended to the lateral femoral epicondyle.(2) Poorly defined abnormal signal intensity presented deep to the ITB adjacent to the lateral femoral epicondyle. (3) Fluid collections medial to the ITB adjacent to the lateral femoral epicondyle. (4) The part of ITB over the lateral femoral epicondyle was thicker. (5) Joint effusion. (6)Other abnormal signs. CONCLUSION: MRI is a relatively good method for detection of ITBFS.


Asunto(s)
Traumatismos en Atletas/diagnóstico , Síndrome de la Banda Iliotibial/diagnóstico , Imagen por Resonancia Magnética , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven
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