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1.
Phys Chem Chem Phys ; 24(27): 16576-16585, 2022 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-35775378

RESUMEN

Molybdenum sulfides and molybdenum oxysulfides are considered a promising and cheap alternative to platinum as a catalyst for the hydrogen evolution reaction (HER). To better understand possible rearrangements during catalyst activation, we perform collision induced dissociation experiments in the gas phase with eight different molybdenum oxysulfides, namely [Mo2O2S6]2-, [Mo2O2S6]-, [Mo2O2S5]2-, [Mo2O2S5]-, [Mo2O2S4]-, [HMo2O2S6]-, [HMo2O2S5]- and [HMo2O2S4]-, on a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. We identify fragmentation channels of the molybdenum oxysulfides and their interconnections. Together with quantum chemical calculations, the results show that [Mo2O2S4]- is a particularly stable species against further dissociation, which is reached from all starting species with relatively low collision energies. Most interestingly, H atom loss is the only fragmentation channel observed for [HMo2O2S4]- at low collision energies, which relates to potential HER activity, since two such H atom binding sites on a surface may act together to release H2. The calculations reveal that multiple isomers are often very close in energy, especially for the hydrogenated species, i.e., atomic hydrogen can bind at various sites of the clusters. S2 groups play a decisive role in hydrogen adsorption. These are further features with potential relevance for HER catalysis.

2.
J Am Soc Mass Spectrom ; 33(9): 1753-1760, 2022 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-35904429

RESUMEN

Molybdenum sulfides are considered a promising and inexpensive alternative to platinum as a catalyst for the hydrogen evolution reaction. In this study, we perform collision-induced dissociation experiments in the gas phase with the halogenated molybdenum sulfides [Mo3S7Cl6]2-, [Mo3S7Br6]2-, and [Mo3S7I6]2-. We show that the first fragmentation step for all three dianions is charge separation via loss of a halide ion. As a second step, further halogen loss competes with the dissociation of a disulfur molecule, whereas the former becomes energetically more favorable and the latter becomes less favorable from chlorine via bromine to iodine. We show that the leaving S2 group is composed of sulfur atoms from two bridging groups. These decomposition pathways differ drastically from the pure [Mo3S13]2- clusters. The obtained insight into preferred dissociation pathways of molybdenum sulfides illustrate possible reaction pathways during the activation of these substances in a catalytic environment.

3.
Am J Trop Med Hyg ; 106(3): 857-860, 2022 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-35008061

RESUMEN

Cutaneous leishmaniasis (CL) frequently entails chronic skin lesions that heal only slowly. Until now, the available therapeutic options are very limited. Here, we present a case of a 5½-year-old Syrian refugee with two progressive lower-leg skin ulcers caused by Leishmania tropica. The patient received topical treatment with LeiProtect®, a newly developed, hydroxypropylcellulose-based, filmogenic gel containing nontoxic concentrations of pharmaceutical sodium chlorite. The skin lesions completely healed within 8 weeks and did not relapse during 1 year of follow-up, underlining the efficacy of this novel local therapy of CL.


Asunto(s)
Leishmania tropica , Leishmaniasis Cutánea , Niño , Cloruros , Humanos , Leishmaniasis Cutánea/tratamiento farmacológico , Persona de Mediana Edad , Preparaciones Farmacéuticas , Siria
4.
Dtsch Med Wochenschr ; 146(3): 193-197, 2021 02.
Artículo en Alemán | MEDLINE | ID: mdl-33513656

RESUMEN

INTRODUCTION: Postinfantile giant cell hepatitis is a rare entity in adult hepatopathy caused by various etiologies that can be summarized by their characteristic giant cells in histopathologic examination. Frequently, association with autoimmune, infectious and hepatotoxic events is described. Therefore, therapy consists in treatment of underlying diseases and immunosuppression. HISTORY: We saw an 76-year-old patient due to histologically proven Postinfantile giant cell hepatitis. Despite administering budesonid as an initial attempt of treatment, no improvement in hepatitis was achieved. Hence, the patient was forwarded to us. FINDINGS: Neither regarding the patient's history nor in laboratory and serological tests, nor in histopathological analysis of liver biopsies an underlying cause of giant cell hepatitis was identified. THERAPY AND COURSE: Despite immunosuppressive therapy with glucocorticoids alone, cyclophosphamide and a monoclonal anti-CD20-antibody, giant cell hepatitis was not controlled. Hence, we started treatment with the calcineurin inhibitor Tacrolimus combined with low-dose prednisolone and thus were able to lower patient's liver values and stabilize hepatitis. CONCLUSION: The good effectiveness of tacrolimus in our patient underlines the important role of calcineurin inhibitors in treating Postinfantile giant cell hepatitis, although rarely reported to date.


Asunto(s)
Inhibidores de la Calcineurina/uso terapéutico , Hemocromatosis , Anciano , Femenino , Hemocromatosis/diagnóstico , Hemocromatosis/tratamiento farmacológico , Hemocromatosis/patología , Humanos , Hígado/patología
5.
Angew Chem Int Ed Engl ; 60(10): 5074-5077, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33332676

RESUMEN

Materials based on molybdenum sulfide are known as efficient hydrogen evolution reaction (HER) catalysts. As the binding site for H atoms on molybdenum sulfides for the catalytic process is under debate, [HMo3 S13 ]- is an interesting molecular model system to address this question. Herein, we probe the [HMo3 S13 ]- cluster in the gas phase by coupling Fourier-transform ion-cyclotron-resonance mass spectrometry (FT-ICR MS) with infrared multiple photon dissociation (IRMPD) spectroscopy. Our investigations show one distinct S-H stretching vibration at 2450 cm-1 . Thermochemical arguments based on DFT calculations strongly suggest a terminal disulfide unit as the H adsorption site.

7.
J Phys Chem C Nanomater Interfaces ; 123(13): 8177-8186, 2019 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-30984322

RESUMEN

Amorphous molybdenum sulfide (MoS x ) is a potent catalyst for the hydrogen evolution reaction (HER). Since mechanistic investigations on amorphous solids are particularly difficult, we use a bottom-up approach and study the [Mo3S13]2- nanocluster and its protonated forms. The mass selected pure [Mo3S13]2- as well as singly and triply protonated [HMo3S13]- and [H3Mo3S13]+ ions, respectively, were investigated by a combination of collision induced dissociation (CID) experiments and quantum chemical calculations. A rich variety of H x S y elimination channels was observed, giving insight into the structural flexibility of the clusters. In particular, it was calculated that the observed clusters tend to keep the Mo3 ring structure found in the bulk and that protons adsorb primarily on terminal disulfide units of the cluster. Mo-H bonds are formed only for quasi-linear species with Mo centers featuring empty coordination sites. Protonation leads to increased cluster stability against CID. The rich variety of CID dissociation products for the triply protonated [H3Mo3S13]+ ion, however, suggests that it has a large degree of structural flexibility, with roaming H/SH moieties, which could be a key feature of MoS x to facilitate HER catalysis via a Volmer-Heyrovsky mechanism.

9.
Angew Chem Int Ed Engl ; 58(11): 3426-3432, 2019 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-30589176

RESUMEN

Manganese oxide (MnOx ) electrocatalysts are examined herein by in situ soft X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) during the oxidation of water buffered by borate (pH 9.2) at potentials from 0.75 to 2.25 V vs. the reversible hydrogen electrode. Correlation of L-edge XAS data with previous mechanistic studies indicates MnIV is the highest oxidation state involved in the catalytic mechanism. MnOx is transformed into birnessite at 1.45 V and does not undergo further structural phase changes. At potentials beyond this transformation, RIXS spectra show progressive enhancement of charge transfer transitions from oxygen to manganese. Theoretical analysis of these data indicates increased hybridization of the Mn-O orbitals and withdrawal of electron density from the O ligand shell. In situ XAS experiments at the O K-edge provide complementary evidence for such a transition. This step is crucial for the formation of O2 from water.

10.
Org Biomol Chem ; 16(40): 7503-7512, 2018 10 17.
Artículo en Inglés | MEDLINE | ID: mdl-30276385

RESUMEN

The bifunctional chelator NODIA-Me holds promise for radiopharmaceutical development. NODIA-Me is based on the macrocycle TACN (1,4,7-triazacyclononane) and incorporates two additional methylimidazole arms for metal chelation and an acetic acid residue for bioconjugation. The original two step synthesis was less than optimal due to low yields and the requirement of semi-preparative RP-HPLC purifications. Here, the overall yield for the preparation of NODIA-Me was improved two- to five-fold via two synthetic routes using different protection/deprotection techniques. This way, it was possible (1) to prepare of NODIA-Me on multi-gram scale and (2) to avoid time-consuming HPLC purifications. Inspired by recent results with nat/68Ga3+, preliminary studies on the radiolabeling properties and complex formation of NODIA-Me with nat/111In3+ were performed. Quantitative radiochemical yields were achieved at ambient temperature providing molar activities of ∼30 MBq nmol-1, which could be increased to ∼240 MBq nmol-1 at 95 °C. At r.t., pH 5.5 was optimal for 111In-labeling, but quantitative yields were also achieved in the pH range from 5.5 to 8.2, when the reaction temperature was increased. Stability tests of 111In complexes in vitro revealed high kinetic stabilities in serum and ligand challenge experiments, which is a consequence of the formation of rigid 1 : 1 indium chelates as shown by NMR studies in solution. In summary, the new synthetic routes afford the BFC NODIA-Me in high yields and on large scale. Further, 111In complexation experiments broaden the scope of our chelating system for radiopharmaceutical applications.


Asunto(s)
Quelantes/química , Complejos de Coordinación/química , Complejos de Coordinación/síntesis química , Imidazoles/química , Indio/química , Técnicas de Química Sintética , Interacciones Hidrofóbicas e Hidrofílicas , Marcaje Isotópico , Cinética , Ligandos
11.
J Neuropathol Exp Neurol ; 77(10): 871-876, 2018 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-30085199

RESUMEN

Epithelioid hemangioendothelioma (EHE) is a rare vascular neoplasm predominantly occurring in the soft tissue. A majority of EHE cases is driven by a WW domain containing transcription regulator protein 1 (WWTR1)-calmodulin-binding transcription activator 1 (CAMTA1) gene fusion. The clinical course of EHE ranges from long-term favorable to rapidly aggressive. Few cases of intracranial EHE have been reported, none of which has been molecularly proven. We report a case of left parietal meningeal EHE, which was resected 15 years after initial radiological detection. Four years prior to surgery, a second atlantooccipital lesion and pulmonary nodules were detected, which remained constant in subsequent radiological controls. The tumor infiltrated the cranial bone. Histology showed an isomorphic tumor with epithelioid cells forming vacuoles that contained erythrocytes. Necrosis was absent and anaplasia and proliferative activity were scant. Immunohistochemistry showed expression of the endothelial markers CD34, CD31, vascular endothelial growth factor, and factor VIII and predominantly nuclear overexpression of CAMTA1. Fluorescence in situ hybridization showed WWTR1-CAMTA1 gene fusion. Our report provides the first case of intracranial EHE with molecular proof of WWTR1-CAMTA1 gene fusion. The slowly progressive clinical course of 15 years is the longest so far reported for intracranial EHE.


Asunto(s)
Neoplasias Encefálicas/diagnóstico por imagen , Proteínas de Unión al Calcio , Reordenamiento Génico , Hemangioendotelioma Epitelioide/diagnóstico por imagen , Péptidos y Proteínas de Señalización Intracelular , Neoplasias Meníngeas/diagnóstico por imagen , Transactivadores , Biomarcadores de Tumor/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/cirugía , Proteínas de Unión al Calcio/genética , Reordenamiento Génico/genética , Hemangioendotelioma Epitelioide/genética , Hemangioendotelioma Epitelioide/cirugía , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Masculino , Neoplasias Meníngeas/genética , Neoplasias Meníngeas/cirugía , Persona de Mediana Edad , Transactivadores/genética , Factores de Transcripción , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ , Carga Tumoral/genética
12.
Inorg Chem ; 57(2): 785-792, 2018 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-29283573

RESUMEN

Calcium manganese oxide films were prepared by cosputter deposition from Mn and CaMnO3 targets and evaluated for their suitability as catalysts for the oxygen evolution reaction (OER). Scanning electron microscopy (SEM) revealed a compact morphology for the as-deposited films and the formation of nanorodlike features on the surfaces after annealing at 600 °C. X-ray-photoelectron-spectroscopy analysis showed that the surface oxidation state is close to +III (as in Mn2O3) for the as-deposited films and increases slightly to a mixture of III and IV after annealing occurs in dry air at 400-600 °C. Glancing-incidence X-ray diffraction (GIXRD) suggested that the CaMnxOy films are amorphous even when heated to 600 °C. However, transmission electron microscopy (TEM) showed that there is actually a polycrystalline component of the film, which best matches Mn3O4 (hausmannite with the average Mn oxidation state of ∼+2.7) but may have a slightly expanded unit cell because of the incorporation of Ca. Electrochemical analyses revealed that the as-deposited CaMnxOy films were OER-inactive. In contrast, annealing at 400 or 600 °C resulted in an increase of ∼15-fold in the current densities, which reached j ≅ 1.5 mA·cm-2 at OER overpotentials of η ≈ 550 mV in cyclic voltammetry (CV) sweeps. For the same η, annealed CaMnxOy electrodes also showed good electrochemical stabilities during 2 h of electrolysis, as rather constant steady-state current densities of j ≅ 0.4-0.5 mA·cm-2 were observed. The thicknesses and surface morphologies of the CaMnxOy films did not change during the electrochemical measurements, indicating that corrosion was negligible. In comparison with a previous study in which Ca-free thin layers of MnOx were evaluated, the results demonstrate that Ca2+ incorporation can enhance the OER activity of MnOx electrocatalysts prepared by sputter deposition. This work provides guidance for designing new electrodes for water oxidation on the basis of the abundant and nontoxic elements manganese and calcium.

14.
Chem Commun (Camb) ; 54(8): 876-879, 2018 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-29236104

RESUMEN

A precursor method has been developed to synthesize Ce(iv) MOFs that could not be prepared directly from Ce(iv) salts. Starting from Ce6 clusters, two Ce-UiO-66 analogues and four tetracarboxylate-based Ce(iv) MOFs could be synthesized. The applied method facilitates framework formation by evading reactive individual Ce(iv)-ions thereby paving the way for further development of Ce-MOFs.

15.
ChemSusChem ; 10(22): 4491-4502, 2017 11 23.
Artículo en Inglés | MEDLINE | ID: mdl-28869720

RESUMEN

Layers of amorphous manganese oxides were directly formed on the surfaces of different carbon materials by exposing the carbon to aqueous solutions of permanganate (MnO4- ) followed by sintering at 100-400 °C. During electrochemical measurements in neutral aqueous buffer, nearly all of the MnOx /C electrodes show significant oxidation currents at potentials relevant for the oxygen evolution reaction (OER). However, by combining electrolysis with product detection by using mass spectrometry, it was found that these currents were only strictly linked to water oxidation if MnOx was deposited on graphitic carbon materials (faradaic O2 yields >90 %). On the contrary, supports containing sp3 -C were found to be unsuitable as the OER is accompanied by carbon corrosion to CO2 . Thus, choosing the "right" carbon material is crucial for the preparation of stable and efficient MnOx /C anodes for water oxidation catalysis. For MnOx on graphitic substrates, current densities of >1 mA cm-2 at η=540 mV could be maintained for at least 16 h of continuous operation at pH 7 (very good values for electrodes containing only abundant elements such as C, O, and Mn) and post-operando measurements proved the integrity of both the catalyst coating and the underlying carbon at OER conditions.


Asunto(s)
Técnicas Electroquímicas/métodos , Compuestos de Manganeso/química , Óxidos/química , Oxígeno/química , Agua/química , Carbono/química , Catálisis , Electrodos , Electrólisis , Espectrometría de Masas , Oxidación-Reducción
16.
Pediatr Blood Cancer ; 64(12)2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28598585

RESUMEN

Epithelioid hemangioendothelioma (EHE) is a rare, vascular sarcoma. Visceral forms arise in the liver/ lungs. We review the clinical and molecular phenotype of pediatric visceral EHE based on the case of a 9-year-old male child with EHE of the liver/lungs. His tumor expressed the EHE-specific fusion oncogene WWTR1-CAMTA1. Molecular characterization revealed a low somatic mutation rate and activated interferon signaling, angiogenesis regulation, and blood vessel remodeling. After polychemotherapy and resection of lung tumors, residual disease remained stable on oral lenalidomide. Literature review identified another 24 children with EHE of the liver/lungs. Most presented with multifocal, systemic disease. Only those who underwent complete resection achieved complete remission. Four children experienced rapid progression and died. In six children, disease remained stable for years without therapy. Two patients died from progressive EHE 21 and 24 years after first diagnosis. Natural evolution of pediatric visceral EHE is variable, and long-term prognosis remains unclear.


Asunto(s)
Hemangioendotelioma Epitelioide/genética , Neoplasias Hepáticas/genética , Neoplasias Pulmonares/genética , Adolescente , Niño , Hemangioendotelioma Epitelioide/terapia , Humanos , Neoplasias Hepáticas/terapia , Neoplasias Pulmonares/terapia , Masculino
17.
Biomed Res Int ; 2016: 2384894, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27990424

RESUMEN

Objective. In this study, we compared prostate cancer detection rates between MRI-TRUS fusion targeted and systematic biopsies using a robot-guided, software based transperineal approach. Methods and Patients. 52 patients received a MRIT/TRUS fusion followed by a systematic volume adapted biopsy using the same robot-guided transperineal approach. The primary outcome was the detection rate of clinically significant disease (Gleason grade ≥ 4). Secondary outcomes were detection rate of all cancers, sampling efficiency and utility, and serious adverse event rate. Patients received no antibiotic prophylaxis. Results. From 52 patients, 519 targeted biopsies from 135 lesions and 1561 random biopsies were generated (total n = 2080). Overall detection rate of clinically significant PCa was 44.2% (23/52) and 50.0% (26/52) for target and random biopsy, respectively. Sampling efficiency as the median number of cores needed to detect clinically significant prostate cancer was 9 for target (IQR: 6-14.0) and 32 (IQR: 24-32) for random biopsy. The utility as the number of additionally detected clinically significant PCa cases by either strategy was 0% (0/52) for target and 3.9% (2/52) for random biopsy. Conclusions. MRI/TRUS fusion based target biopsy did not show an advantage in the overall detection rate of clinically significant prostate cancer.


Asunto(s)
Biopsia Guiada por Imagen/métodos , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/patología , Anciano , Antibacterianos/química , Reacciones Falso Positivas , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/cirugía , Reproducibilidad de los Resultados , Estudios Retrospectivos , Robótica , Programas Informáticos
18.
Dalton Trans ; 45(43): 17464-17473, 2016 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-27738675

RESUMEN

The reaction products and intermediates of the three CO-releasing manganese(i) coordination compounds [Mn(tpm)(CO)3]+, [Mn(bpza)(CO)3] and [Mn(tpa)(CO)3]+ were analysed by combining IR-spectroscopy, electrochemical measurements and single-crystal XRD. The intermediate formation of manganese(i) biscarbonyl compounds and the rather facile oxidation of these species were identified as key reaction steps that accompany CO liberation. For the use of [MnI(CO)3] complexes as light-triggered CO sources, the results indicate that in this case photo- and redox-chemistry seem to be strongly coupled which could be important and potentially even useful in the pharmacological context. Additionally, one has to be aware of the fact that [MnII(κ3-L)(solv)3]2+ complexes, the primary reaction products after CO substitution, are able to bind to proteins, which was demonstrated using bovine serum albumin as a model. And finally it could be shown that the CO-release reactions can be used as a new synthetic route to prepare multinuclear µ-oxido-bridged manganese complexes: the mixed-valence compound [Mn(µ-O)2(tpa)2]3+ could be prepared in a single step from [Mn(tpa)(CO)3]+via photo- or electrochemically induced CO substitution.

19.
Top Curr Chem ; 371: 49-72, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-25980320

RESUMEN

The catalytic oxidation of water to molecular oxygen is a key process for the production of solar fuels. Inspired by the biological manganese-based active site for this reaction in the enzyme Photosystem II, researchers have made impressive progress in the last decades regarding the development of synthetic manganese catalysts for water oxidation. For this, it has been especially fruitful to explore the many different types of known manganese oxides MnOx. This chapter first offers an overview of the structural, thermodynamic, and mechanistic aspects of water-oxidation catalysis by MnOx. The different test systems used for catalytic studies are then presented together with general reactivity trends. As a result, it has been possible to identify layered, mixed Mn (III/IV)-oxides as an especially promising class of bio-inspired catalysts and an attempt is made to give structure-based reasons for the good performances of these materials. In the outlook, the challenges of catalyst screenings (and hence the identification of a "best MnOx catalyst") are discussed. There is a great variety of reaction conditions which might be relevant for the application of manganese oxide catalysts in technological solar fuel-producing devices, and thus catalyst improvements are currently still addressing a very large parameter space. Nonetheless, detailed knowledge about the biological catalyst and a solid experimental basis concerning the syntheses and water-oxidation reactivities of MnOx materials have been established in the last decade and thus this research field is well positioned to make important contributions to solar fuel research in the future.


Asunto(s)
Biomimética , Compuestos de Manganeso/química , Óxidos/química , Agua/química , Catálisis , Oxidación-Reducción
20.
Gynecol Endocrinol ; 31(11): 856-9, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26369991

RESUMEN

The decision to preserve the uterus in a young nulliparous woman with an extremely rare tumor is challenging. Uterine tumor resembling ovarian sex cord-like tumor (UTROSCT) belongs to the rarest uterine pathologies. A 22-year-old nulligravida with uterine bleeding underwent a hysteroscopic resection of an intrauterine mass presumed as grade-1 submucous myoma. According to the presence of sex cord-like differentiation and positivity for calretinin, CD99, estrogen receptor, vimentin, WT1 and Melan-A, the tumor was diagnosed as UTROSCT. After 28 months, without any adjuvant therapy, the patient is still free of recurrence. This is the youngest patient with UTROSCT reported so far, with the longest follow-up among all five cases treated via hysteroscopy. Although UTROSCT has been traditionally treated with hysterectomy (with or without bilateral salpingo-oophorectomy), no established treatment protocol for UTROSCT exists. UTROSCT shows a low-malignant potential, but metastasizing and recurrent cases occur. In light of the probably less aggressive tumor biology and with respect to the patient's autonomy, a conservative, uterus preserving treatment appears to be justified in selected cases in which close follow-up can be guaranteed. Further case reports are needed to prove the safety of organ-preserving strategy in UTROSCT.


Asunto(s)
Preservación de la Fertilidad/métodos , Histeroscopía , Tratamientos Conservadores del Órgano/métodos , Tumores de los Cordones Sexuales y Estroma de las Gónadas/cirugía , Neoplasias Uterinas/cirugía , Útero/cirugía , Femenino , Humanos , Adulto Joven
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