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Treatment of PICA aneurysms can be technically challenging by either surgical or endovascular means. Our aim was to report our preliminary experience with intrasaccular flow disruption using the Woven EndoBridge (WEB) for the treatment of proximal PICA aneurysms.Sixteen PICA aneurysms treated with the WEB at 3 institutions were retrospectively reviewed. Baseline patient and aneurysm characteristics, procedural specifics, clinical outcomes, and angiographic results were evaluated.All aneurysms were located at the proximal, anteromedullary segment of the PICA. Seven aneurysms were ruptured. The median aneurysm size was 3.9 mm (range, 2-12 mm), and all aneurysms were wide-neck. WEB deployment failed in 1 case due to WEB protrusion in a small PICA aneurysm. Additional stent implantation was required for 2 aneurysms to improve intra-aneurysmal WEB positioning. One patient developed a partial posterior cerebral artery territory infarction with transient hemianopsia. Intraoperative rerupture of a ruptured aneurysm could be immediately stopped by WEB deployment due to intrasaccular stasis; however, it might have contributed to a slight disability of the patient. At last angiographic follow-up, 12/15 aneurysms (80%) were completely occluded and 3/15 (20%) had a neck remnant.The preliminary results indicate that WEB treatment of proximal PICA aneurysms is feasible with a reasonable safety and efficacy profile. The advantages of intrasaccular flow disruption include preservation of the PICA, durable aneurysm occlusion, and omission of antiplatelet therapy. The low-profile WEB 17 delivery system might enable navigation to distal PICA aneurysms, which needs to be addressed further.

Zielsetzung: Die Jodaufnahme des Knochenmarks in der Dual-Energy-CT (DECT) ist bei malignen Erkrankungen erhöht. Unser Ziel war es, den physiologischen Referenzbereich der Jodaufnahme des Knochenmarks nach intravenöser Kontrastmittelapplikation zu untersuchen und die Abhängigkeit von der Knochendichte (BMD), Jod-Blutpool, Patientenalter und Geschlecht zu erforschen. Material und Methoden: Retrospektive Analyse von onkologischen Patienten ohne metastasierte Erkrankung. Die DECT-Untersuchungen wurden auf einem Spektraldetektor-CT-Scanner in portalvenöser Phase durchgeführt. Die Brust- und Lendenwirbelsäule wurden von einem vortrainierten neuronalen Netz segmentiert, um volumetrische Jodkonzentrationsdaten [mg/ml] zu erhalten. Die BMD wurde mit einer CE-zertifizierten Software gemessen. Der Jod-Blutpool wurde durch ROI-basierte Messungen in den großen abdominellen Gefäßen ermittelt. Es wurde ein multivariates Regressionsmodell mit der abhängigen Variable "mediane Jodaufnahme im Knochenmark" modelliert. Standardisierte Regressionskoeffizienten (β) zeigten die Effektgröße der einzelnen Kovariaten auf die abhängige Variable. Ergebnisse: 678 konsekutive DECT-Untersuchungen von 189 Individuen (93 weiblich, Alter 61,4±16,0 Jahre) wurden eingeschlossen. Die AI-basierte Segmentierung lieferte volumetrische Daten von 97,9% der einbezogenen Wirbel (n=11.286). Das 95. Perzentil der Jodaufnahme im Knochenmark, als Surrogat für den oberen Grenzwert der physiologischen Verteilung, lag zwischen 4,7 und 6,4 mg/ml. BMD (p

Particularly at the beginning, the COVID-19 (coronavirus disease 2019) pandemic caused a reduction in the number of interventions in interventional radiology. At the same time, interventional training became more challenging. Infectious patients and disease transmission within interventional radiology departments continue to pose significant challenges.This article describes the status and recommendations for interventional radiological procedures in COVID-19 patients.Guidelines and recommendations from international and national societies as well as original works and reviews were evaluated.Interventional radiological care of COVID-19 patients with complicated courses of infection has become established during the course of the pandemic. To protect patients and staff, interventions in COVID-19 patients should be prioritized, performed in separate procedure rooms if possible, and patients should be tested before interventions. Logistics, staff planning, and hygiene measures should be continuously optimized.Structured workflows within interventional radiology in dealing with COVID-19 patients appear necessary to minimize infection risks and to guarantee the staff's work capability and health. In order to develop concepts for the handling of COVID-19 patients and to be prepared for potential upcoming waves of infections, recommendations of the Robert Koch Institute (RKI) and (inter-)national professional societies are helpful.HINTERGRUND: Insbesondere zu Beginn führte die COVID-19-Pandemie („coronavirus disease 2019“) zu einer Reduktion der Eingriffszahlen in der interventionellen Radiologie. Gleichzeitig wurde die interventionelle Weiterbildung erschwert. Infektiöse PatientInnen und Ansteckungen innerhalb interventionell-radiologischer Abteilungen stellen weiterhin große Herausforderungen dar.Die vorliegende Arbeit beschreibt den Status und Empfehlungen zur interventionell-radiologischen Versorgung bei COVID-19-PatientInnen.Richtlinien und Empfehlungen aktueller internationaler und nationaler Fachgesellschaften sowie Originalarbeiten und Übersichtsarbeiten seit Pandemiebeginn 2020 wurden evaluiert.Die interventionell-radiologische Versorgung von COVID-19-PatientInnen mit komplikativen Infektionsverläufen hat sich im Verlauf der Pandemie etabliert. Zum Schutz von PatientInnen und Personal sollten Interventionen bei COVID-19-PatientInnen priorisiert werden sowie, wenn möglich, in separaten Eingriffsräumen durchgeführt und die PatientInnen vor Eingriffen getestet werden. Die Logistik, Personalplanung und Hygienemaßnahmen sollten kontinuierlich optimiert werden.Strukturierte Arbeitsabläufe innerhalb der interventionellen Radiologie im Umgang mit COVID-19-PatientInnen erscheinen notwendig, um Infektionsrisiken zu minimieren und die Arbeitsfähigkeit und Gesundheit des Personals zu garantieren. Um Konzepte im Umgang mit COVID-19-PatientInnen zu entwickeln und für künftige, potenzielle Infektionswellen vorbereitet zu sein, sind die Empfehlungen des Robert-Koch-Instituts (RKI) und der (inter)nationalen Fachgesellschaften hilfreich.

Supported MoOx on mixed CeO2–TiO2 was investigated for the oxidative dehydrogenation of ethane (ODHE) using CO2 as a mild oxidant. Raman spectroscopic characterization of the synthesized catalysts under dehydrated conditions suggested that surface MoOx species prefer to anchor on the crystalline domains of TiO2. Upon increasing the amount of CeO2 in the mixed oxide support, significant spectral changes were observed, especially in the ∼900–950 cm−1 region where Mo–O–M bonds are expected. The catalytic behaviors of Mo as opposed to pure support materials were distinct. As the ceria content in the support increased, MoOx catalysts promoted oxidative dehydrogenation pathways via the Mars–van Krevelen mechanism, while pure supports appeared to favor ethane direct dehydrogenation. Investigation of structure–function relationships via in situ Raman spectroscopic efforts revealed that adding ceria not only changed the redox properties of the support but also improved those of the deposited amorphous MoOx species. We also show that upon incorporation of ceria into the support, CO2 directly participates in the reoxidation of the dispersed MoOx species during catalysis. This effect was distinct from the participation of CO2 in the reverse water gas shift reaction. Operando Raman spectra revealed that the presence of CO2 prolonged the existence of the 930 cm−1 feature which appears to correlate well with the relative contribution of the oxidative versus non-oxidative pathway in ethane dehydrogenation.

Background Following neurooncological treatment of brain tumors, neurooncologists are often confronted with equivocal MRI findings (e.g., treatment-related changes such as pseudoprogression, non-measurable contrast-enhancing lesions, T2/FLAIR signal alterations, pseudoresponse). Especially in Europe, amino-acid PET is increasingly integrated into multidisciplinary neurooncological tumor boards (MNTB) to overcome these diagnostic uncertainties. We evaluated the correctness of MNTB decisions, in which amino acid PET findings were taken into account. Material and Methods In a single-university center study, we retrospectively evaluated 182 MNTB decisions of 154 patients with histomolecularly defined WHO grade 3 or 4 gliomas (n=123), including glioblastoma (n=80), anaplastic glioma (n=42), and gliosarcoma (n=1), or brain metastases (n=31) secondary to lung cancer, melanoma, breast cancer, or colorectal cancer presenting equivocal MRI findings following anticancer treatment. All patients underwent O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET imaging as an adjunct for decision-making. Additionally, the patients’ clinical status, pretreatment, and conventional MRI findings were considered for decision-making. The presence of neoplastic tissue was considered if the mean FET uptake as assessed by tumor-to-brain ratios was > 2.0. MNTB decisions were validated using the neuropathological result in 42% (n=77) or clinicoradiologically in 58% (n=105). The diagnostic performance of MTNB decisions was evaluated using 2x2 contingency tables. Results The validation of all 182 MNTB recommendations, which integrated FET PET in the decision-making process, were correct in 95% (sensitivity, 97%; specificity, 75%; positive predictive value, 96%). Due to tumor progression, MNTB recommendations prompted a treatment change in 88% (n=160 of 182 decisions). When FET PET findings suggested progressive disease (n=157), MNTB decisions were correct in 96% (positive predictive value, 97%). In 22 MNTB decisions with the recommendation to continue the current treatment regimen, 82% were correctly identified as treatment-related changes. Conclusion FET PET seems to have a significant impact on MNTB decisions. A prospective evaluation of MNTB decisions with and without the integration of FET PET is warranted to define the added value of FET PET.

The production of olefins via on-purpose dehydrogenation of alkanes allows for a more efficient, selective and lower cost alternative to processes such as steam cracking. Silica-supported pincer-iridium complexes of the form [(≡SiO-R4POCOP)Ir(CO)] (R4POCOP = κ3-C6H3-2,6-(OPR2)2) are effective for acceptorless alkane dehydrogenation, and have been shown stable up to 300 °C. However, while solution-phase analogues of such species have demonstrated high regioselectivity for terminal olefin production under transfer dehydrogenation conditions at or below 240 °C, in open systems at 300 °C, regioselectivity under acceptorless dehydrogenation conditions is consistently low. In this work, complexes [(≡SiO-tBu4POCOP)Ir(CO)] (1) and [(≡SiO-iPr4PCP)Ir(CO)] (2) were synthesized via immobilization of molecular precursors. These complexes were used for gas-phase butane transfer dehydrogenation using increasingly sterically demanding olefins, resulting in observed selectivities of up to 77%. The results indicate that the active site is conserved upon immobilization.

Pincer-ligated iridium complexes of the form [(R4PCP)IrL] (R4PCP = κ3-C6H3-2,6-(XPR2)2; X = CH2, O; R = tBu, iPr) have previously been shown competent for acceptorless alkane dehydrogenation when s...

Catalytic ethane dehydrogenation was studied with density functional theory (DFT) calculations to investigate the differing role of Sn in the bulk and surface of PtSn alloys on the activity, selectivity, and stability of the catalyst. Pristine Pt(111), a surface alloy of Pt3Sn/Pt(111) and a bulk alloy of Pt3Sn(111) were compared. Binding energies of adsorbates were weakened by Sn on both alloys. With few changes for binding geometries of adsorbates, the change in binding energies was mainly attributed to the changes in the electronic interaction due to the strain effect and/or the ligand effect from d-band theory on the alloys. Especially, the combination of ligand and strain effects on the bulk alloy made the binding energies of adsorbates generally weaker than on Pt but stronger than on the surface alloy. In the successive dehydrogenation of C2Hx species, the activity was expected in the order of Pt > Pt3Sn > Pt3Sn/Pt by comparing the activation energies for ethene formation. The selectivity toward ethene was predicted using two descriptors from which the best selectivity was expected on Pt3Sn/Pt. Sn in the bulk made the gap between the barriers for ethene desorption and further dehydrogenation comparable, whereas ethene desorption was much more favorable on Pt3Sn/Pt. The preference for ethene formation from ethyl was also weakened on Pt3Sn. Therefore, despite the higher Sn composition, worse selectivity was predicted for Sn-rich bulk alloy than the surface alloy, followed by Pt.

Objectives Cutaneous squamous cell carcinoma (cSCC) is a common cancer in Caucasian populations. Treatments registered for high-risk cSCC are still undetermined. Experimental data have demonstrated possibly useful effects of a combined application of beta‑blockers in cancer therapy. The goal of this study was to examine the efficacy of propranolol in the treatment of cSCC and its impact on apoptosis. Thus, we aimed to investigate the apoptotic pathway protein levels and activity in beta‑blocker‑treated cSCC cells. Materials and methods The study was performed on human cSCC cancer cell line culture. One of the cSCC cell lines was treated with propranolol, whereas no treatment was given to the other group. Then, the levels of apoptotic pathway proteins were determined by ELISA test in both groups. Results The propranolol treatment group exhibited a remarkable difference as compared with the other group. It was found that propranolol treatment enhanced the activity of caspase-3 while the expression of bax, wee1, gadd153, grp78 and AIF decreased bcl-2 which is antiapoptotic protein in cSCC cell lines. Conclusion Our results suggest that propranolol treatment has anti-cancer properties with an effect on various apoptotic pathways in cSCC. These data are important because propronalol may be involved in future cSCC treatment (Tab. 1, Fig. 3, Ref. 22).

Accident analyse in marine industry is one of the critical issues for safety practitioners to prevent loss of life. Although considerable efforts were undertaken to prevent marine accident, numerous researches revealed that marine accidents are still on-going. In order to minimize accidents in the marine transportation, this paper presents a proactive decision- making tool which is integrating Decision-Making Trail and Evaluation Laboratory (DEMATEL) method with interval type-2 fuzzy sets (IT2FSs). As the DEMATEL enables to analyse cause and effect relationship in decision-making, the IT2FSs overcome ambiguity and vagueness of linguistic assessment of decision-makers through the DEMATEL. Thus, significant accident causal factors and their effects can be analysed on the basis of cause-effect diagram. The application of proposed approach is demonstrated with a real ship collision case. Beside its theoretical contribution, the proposed approach provides practical benefits to ship owners and operators to perceive cause and effect relationship and to avoid marine accident.

Plasmonic nanostructure/semiconductor composites are receiving great interest as powerful photocatalytic platforms able to increase solar energy conversion efficiency compared to more traditional approaches. The possibility to grow a thin titania shell onto the gold nanoparticle, thus substantially increasing the metal–semiconductor area of contact, is expected to be ideal for photocatalytic water reduction, especially if the titania (TiO2) coating displays limited thickness and high crystallinity. We argue however that the morphology of the underlying gold nanoparticle and the quality of the interface are the main drivers of photocatalytic performance. Herein, we show how we can synthesize TiO2-coated gold nanostar- and gold nanorod-based photocatalysts and identify the most important design parameters that one should be focusing on for the optimization of hot electron-based photocatalysts. In addition to nanoparticle morphology and interface quality, we determine that the integrated absorptivity of the plasmon band and the uniformity and crystallinity of the semiconductor shell are important, even though to a lesser extent. These results may prove interesting not only to increase production rates in hydrogen evolution reactions or other chemical conversions, but also to decouple and understand additional mechanisms driving photocatalysis, other than the sequential, hot electron mediated one, as we reported before.

Continuing improvement in the field of virtual crack closure technique of metals provides the opportunity for reliable probabilistic fatigue crack growth. The paper presents an analysis of mode I fatigue crack growth in low carbon steel. Experiment was carried out with Single Edge Notched Tension (SENT) specimens to determine its fatigue crack growth parameters on the specimens under constant amplitude loading. Linear elastic fracture mechanic crack path was modelled with the finite element method according to its experimental observation using the virtual crack closure technique (VCCT) in MSC Marc/Mentat. The simulation predicts the fatigue crack growth rate in high cycle fatigue. The simulated fatigue crack growth rate (FCGR) produced using SENT model represents good similar feature with the experimental process at stress ratio R = 0 Based on the remeshing model, it is also found that the results of crack growth rate and cycle count show good agreement within acceptable discrepancy compared to the experiment from Paris law diagram.

Background: This national cross-sectional survey aimed to assess the iodine status in pregnant women and their offspring, and also to demonstrate regional differences by measuring urinary iodine concentration (UIC). For each woman and her newborn a questionnaire was prepared with basic facts as age, parity number or birth weight and additional information regarding thyroid diseases, use of iodized salt in the household, extra iodine supplementation during pregnancy, education level and wage income. Methods: The target population represented 1444 pregnant women who gave birth between January 1 st, 2018 and 2019, and their offspring. Iodine deficiency for pregnant women and their offspring were defined as urine iodine level

Circulating autoantibodies (auto-Abs) neutralizing high concentrations (10 ng/ml; in plasma diluted 1:10) of IFN-α and/or IFN-ω are found in about 10% of patients with critical COVID-19 (coronavirus disease 2019) pneumonia but not in individuals with asymptomatic infections. We detect auto-Abs neutralizing 100-fold lower, more physiological, concentrations of IFN-α and/or IFN-ω (100 pg/ml; in 1:10 dilutions of plasma) in 13.6% of 3595 patients with critical COVID-19, including 21% of 374 patients >80 years, and 6.5% of 522 patients with severe COVID-19. These antibodies are also detected in 18% of the 1124 deceased patients (aged 20 days to 99 years; mean: 70 years). Moreover, another 1.3% of patients with critical COVID-19 and 0.9% of the deceased patients have auto-Abs neutralizing high concentrations of IFN-β. We also show, in a sample of 34,159 uninfected individuals from the general population, that auto-Abs neutralizing high concentrations of IFN-α and/or IFN-ω are present in 0.18% of individuals between 18 and 69 years, 1.1% between 70 and 79 years, and 3.4% >80 years. Moreover, the proportion of individuals carrying auto-Abs neutralizing lower concentrations is greater in a subsample of 10,778 uninfected individuals: 1% of individuals 80 years. By contrast, auto-Abs neutralizing IFN-β do not become more frequent with age. Auto-Abs neutralizing type I IFNs predate SARS-CoV-2 infection and sharply increase in prevalence after the age of 70 years. They account for about 20% of both critical COVID-19 cases in the over 80s and total fatal COVID-19 cases. © 2021 The Authors, some rights reserved.

The incidence, treatment and prognosis of patients with brain metastases have substantially changed during the last decades. While the survival time after diagnosis of cerebral metastases was on average a maximum of 3-6 months only 10 years ago, the survival time could be significantly improved due to novel surgical, radiotherapeutic and systemic treatment modalities. Only a few years ago, the occurrence of brain metastases led to a withdrawal from systemic oncological treatment and the exclusion of drug therapy studies and to a purely palliatively oriented treatment in the sense of whole brain radiation therapy (WBRT) with or without surgery. The increasing availability of targeted and immunomodulatory drugs as well as adapted radio-oncological procedures enable increasingly more personalized treatment approaches. The aim of this review article is to demonstrate the progress and complexity of the treatment of brain metastases in the context of modern comprehensive interdisciplinary concepts.Die Inzidenz, Behandlung und Prognose von Patienten mit Hirnmetastasen haben sich in den letzten Jahrzehnten grundlegend geändert. Während die Überlebenszeit zerebral metastasierter Patienten noch vor 10 Jahren durchschnittlich 3 bis maximal 6 Monate betrug, konnte diese aufgrund neuer Methoden in der operativen, strahlentherapeutischen und systemischen Behandlung deutlich verlängert werden. Noch vor wenigen Jahren führte das Auftreten von Hirnmetastasen zu einem Rückzug aus der systemisch-onkologischen Behandlung und dem Ausschluss aus medikamentösen Therapiestudien und zu einer rein palliativ orientierten Behandlung im Sinne einer Ganzhirnbestrahlung (WBRT) mit oder ohne Operation. Die zunehmende Verfügbarkeit zielgerichteter und immunmodulatorischer Medikamente sowie adaptierte radioonkologischer Verfahren erlauben immer mehr individualisierte Therapieansätze. Im Rahmen dieser Übersichtsarbeit soll der Fortschritt und die Komplexität der Behandlung von Hirnmetastasen im Kontext moderner fachübergreifender Konzepte dargelegt werden.

While several metal phosphides have attracted significant attention in the last several years due to their potential use as photocatalytic and hydrotreating catalysts, iridium phosphide has remained largely unexplored. In this work, silica-supported pincer-iridium species are thermolyzed, resulting in deconstruction of the tridentate ligand precursor and formation of a sub-nanometer iridium phosphide phase characterized by 31P magic angle spinning nuclear magnetic resonance (31P-MAS-NMR), X-ray absorption spectroscopy (XAS), and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The support material was found to play an active role in determining the product of the surface thermolysis, with the silica supported material generating phosphorus rich iridium phosphide nanoparticles. The resulting silica-supported iridium phosphide phase is explored as a thermocatalyst for non-oxidative butane dehydrogenation, achieving high initial reaction rates up to 900 molbutenes molcatalyst-1 hr-1 and a terminal olefin selectivity of up to 70 %.

While several metal phosphides have attracted significant attention in the last several years due to their potential use as photocatalytic and hydrotreating catalysts, iridium phosphide has remained largely unexplored. In this work, silica-supported pincer-iridium species are thermolyzed, resulting in deconstruction of the tridentate ligand precursor and formation of a sub-nanometer iridium phosphide phase characterized by 31P magic angle spinning nuclear magnetic resonance (31P-MAS-NMR), X-ray absorption spectroscopy (XAS), and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The support material was found to play an active role in determining the product of the surface thermolysis, with the silica supported material generating phosphorus rich iridium phosphide nanoparticles. The resulting silica-supported iridium phosphide phase is explored as a thermocatalyst for non-oxidative butane dehydrogenation, achieving high initial reaction rates up to 900 molbutenes molcatalyst-1 hr-1 and a terminal olefin selectivity of up to 70 %.

The production of olefins via on-purpose dehydrogenation of alkanes allows for a more efficient, selective and lower cost alternative to processes such as steam cracking. Silica-supported pincer-iridium complexes of the form [(≡SiO-R4POCOP)Ir(CO)] (R4POCOP = κ3-C6H3-2,6-(OPR2)2) are effective for acceptorless alkane dehydrogenation, and have been shown stable up to 300 °C. However, while solution-phase analogues of such species have demonstrated high regioselectivity for terminal olefin production under transfer dehydrogenation conditions at or below 240 °C, in open systems at 300 °C, regioselectivity under acceptorless dehydrogenation conditions is consistently low. In this work, complexes [(≡SiO-tBu4POCOP)Ir(CO)] (1) and [(≡SiO-iPr4PCP)Ir(CO)] (2) were synthesized via immobilization of molecular precursors. These complexes were used for gas-phase butane transfer dehydrogenation using increasingly sterically demanding olefins, resulting in observed selectivities of up to 77%. The results indicate that the active site is conserved upon immobilization.

Pincer-ligated iridium complexes of the form [Ir(R4PCP)L] (R4PCP = κ3-C6H3-2,6-(XPR2)2; X = CH2, O; R = tBu, iPr) have previously been shown competent for acceptorless alkane dehydrogenation when supported on silica. It was observed by post-catalysis solid-state NMR that silica-tethered [Ir(C2H4)(≡SiO-tBu4POCOP)] (3-C2H4) was converted fully to [Ir(CO)(≡SiO-tBu4POCOP)] (3-CO) at 300 °C. In this work, the characterization of species under dehydrogenation reaction conditions far from equilibrium between butane and butenes (approach to equilibrium Q/Keq = 0.3 at 300 °C) is performed with operando Diffuse Reflectance Infrared Fourier-Transform Spectroscopy (DRIFTS) to show the kinetics of species conversion from 3-C2H4 to 3-CO. It is further found that [IrClH(≡SiO-tBu4POCOP)] (3-HCl), a species considered to be a precatalyst for alkane dehydrogenation, is also fully converted to 3-CO. A mechanism of decomposition is proposed that implicates surface silanol groups, while carbon monoxide acts as a “stabilizer” for the catalyst by promoting their reductive elimination and maintaining the complex in the I oxidation state.

Supported MOx (M= Mo, V) on mixed CeO2-TiO2 were investigated for the oxidative dehydrogenation of ethane (ODHE) using CO2 as a mild oxidant. Raman spectroscopic characterization of the synthesized catalysts under dehydrated conditions suggest that surface MoOx species prefer to anchor on the crystalline domains of TiO2. Upon increasing the amount of CeO2 in the mixed oxide support, an intense and broad band at ~930cm-1 underscored that the prevalent species tend to be polymeric (MoOx)n domains. On the other hand, in the case of VOx catalysts, a gradual shift in the symmetric stretching of the vanadyl (V=O) Raman band with increasing CeO2 content was observed that points at the gradual anchoring of the surface vanadia species on both TiO2 and CeO2 thus highlighting the possible existence of the amorphous VOx to be located at the interface of the two mixed oxides. The catalytic behavior of Mo and V were distinct. As the ceria content in the support increased, MoOx catalysts promoted the ODHE via Mars van Krevelen mechanism while VOx catalysts appeared to favor ethane direct dehydrogenation. Investigation of structure-function relationships via in-situ Raman spectroscopic efforts revealed that adding ceria not only changed the redox properties of the support but also improved those of the deposited metal oxide. We also show that upon incorporation of ceria into the support, CO2 directly participates in the reoxidation of the dispersed MoOx species during catalysis. This effect was distinct from the reaction of CO2 in the reverse water gas shift reaction. Operando Raman spectra revealed that the presence of CO2 enhances the stability of the bridging Mo–O–Mo bond of polymeric molybdena domains, which is proposed to affect the relative contribution of oxidative versus non-oxidative pathways in ethane dehydrogenation.

Commercial anatase phase titanium dioxide was annealed under various gases (hydrogen, nitrogen, argon, and air) to induce the formation of defects. While annealing in the absence of oxygen there was a notable increase in the concentration of paramagnetic defects as measured by Electron Paramagnetic Resonance (EPR) and X-ray Photoelectron Spectroscopy (XPS). The presence of these defects increased the metal-free photocatalytic activity of the samples towards hydrogen evolution from photocatalytic methane steam reforming (MSR) under UV illumination. Catalyst activity was stable for over 42 h while illuminated owing to the regeneration of Ti3+ defects by UV photoexcitation, but rapidly decayed in the dark. The high concentration of unique Ti3+ defect sites generated during annealing catalyze hydrogen evolution, avoiding the need for precious metal cocatalysts, while anatase lacking these defects is inactive. This work shows that the implementation of defect-rich anatase TiO2 provides new catalytic pathways for hydrogen generation from photocatalytic methane steam reforming.

The methane steam reforming (MSR) mechanism on the anatase TiO2 (101) surface has been investigated using periodic density functional theory. Reaction energies for several pathways were calculated, and pathways involving high energy intermediates were eliminated from consideration. The remaining pathways all involved formaldehyde and formyl as intermediates. Activation energy barriers were calculated for these, revealing that C–H activation in methane and elementary dehydrogenation reactions in general involved very high energy transition states when calculated on clean surfaces. When water was coadsorbed on reaction surfaces as chemisorbed OH and H, hydrogen transfer reactions were facilitated by the proximity between hydrogen donor and acceptor and the strong affinity of hydroxyl for hydrogen. As the product of such hydrogen transfer reactions was physisorbed water, water activation completes the catalytic cycle, and the role of water can be termed cocatalytic. Cocatalytic water lowered the most difficu...

The water gas shift reaction (WGS) mechanism on the anatase TiO2 (101) surface has been investigated using periodic density functional theory. Reaction energies and activation energy barriers for direct CO oxidation and associative pathways with carboxyl and formate intermediates were calculated and compared. Unassisted by water, the formation of formate was infeasible due to the difficulty in transferring hydrogen from the anatase surface to hydrogenate CO, while the carboxyl mechanism had the lowest apparent activation energy barrier among the three. Coadsorbed water species were found to be effective hydrogen transfer cocatalysts, with molecularly physisorbed water acting as a hydrogen donor and dissociatively chemisorbed water acting as a hydrogen acceptor. Using water as the hydrogen donor, CO hydrogenation became competitive with the carboxyl mechanism, indicating that the reactivity of water could change the relative competitiveness of different WGS pathways. These results suggest that adsorbed wat...

Elucidating structural and compositional polymorph changes of multiphase semiconductors in a quick and quantitative manner is important for their manufacturing and applications in catalysis alike. Derivative peak fitting of diffuse reflectance UV–visible spectra (DPR) is presented as an inexpensive, fast, and quantitative method to estimate both the composition of a multiphase semiconductor sample as well as the band gap energies of each component semiconductor in the mixture. Degussa P25 TiO2, a widely used catalyst support and semiconductor photocatalyst, is a mixture of anatase and rutile polymorphs. The as-received P25 samples were subjected to grinding, sieving, and calcination or a combination of these operations. Samples were analyzed via DPR, X-ray diffraction (XRD), and Raman spectroscopy to quantify the percentage of anatase and rutile polymorphs present in each sample. Compositional measurements from DPR were in good quantitative agreement with XRD and Raman analysis. The application of in situ...

Nanoparticulate (3–10 nm) TiO2 polymorphs, i.e., rutile, anatase, and srilankite (also known as TiO2-II or α-PbO2-type TiO2) phases are produced via low-pressure (e.g., 20 torr) flame synthesis at temperatures ranging from 1560K to 2650K, with burner flow velocities varying from 150 to 300 cm/s, using titanium tetra-isopropoxide (TTIP) as precursor. Interestingly, added carbon (i.e., ethylene) in the feed stream produces nanoparticles of the generally characteristic low-temperature high-pressure metastable srilankite phase. The as-synthesized nanopowder is composed of either rutile or srilankite phase, with composition dependent on particle residence time in the flow field. Under the same conditions, feed gas without carbon, e.g., hydrogen, yields anatase phase TiO2. Post heat treatment up to 773K in thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) highlights the thermal stability of the samples, while x-ray photoelectron spectroscopy (XPS) indicates the presence of carbon, with absences of Ti3+, Ti–C, and nitrogen. Microscopy reveals morphology on both the micrometer scale (scanning electron microscopy, SEM) and nanometer scale (transmission electron microscopy, TEM), while x-ray diffraction (XRD) and selected area electron diffraction (SAED) confirm polymorph variation under different synthesis conditions. CHN analysis determines that the synthesized srilankite contains a greater weight percentage of carbon than does anatase. Excess carbon doped into the lattice during low-pressure flame synthesis seems to be the key in stabilizing the high-pressure srilankite phase for such nanoparticles.

On the occasion of Alexis T. Bell’s fiftieth year at Berkeley, we are honored to discuss a few aspects of his extensive contributions to catalysis, reaction engineering, and understanding of molecular-scale structure in catalytic processes. The illustrations provided here help reveal some of his traits most valued by our community: a drive to employ the best methods of instrumentational and computational analysis available; the instinct to search for the essence of the most important problems at hand, and the skill to write about them with exceptional clarity; and the formation and nurturing of collaborative teams to focus on the most essential questions.

The effects of alloying platinum with transition and post-transition metals on the kinetics and thermodynamics of dehydrogenation and coke formation pathways during light alkane dehydrogenation have been studied using density functional theory. Supported Pt catalysts are known to be active for light alkane dehydrogenation, but the high temperatures required by these endothermic reactions leads to significant coke formation and deactivation. A limited set of Pt alloys have been investigated experimentally previously, with decreases coke formation and deactivation. Using periodic density functional theory, we have investigated a wider range of Pt-alloy compositions, including metals from groups 7–15, to better understand the reduction in surface carbon formation and enhanced selectivity during ethane dehydrogenation. The post-transition metal alloys show the greatest ability to decrease the binding energy of carbonaceous species. At low alloy coverage (1/4 ML), these elements affect binding energies primari...

Plasmonic nanostructure/semiconductor composites are receiving great interest as powerful photocatalytic platforms able to increase solar energy conversion efficiency compared to more traditional approaches. The possibility to grow a thin titania shell onto the gold nanoparticle, thus substantially increasing the metal-semiconductor area of contact, is expected to be ideal for photocatalytic water reduction, especially if the titania (TiO2) coating displays limited thickness and high crystallinity. We argue however that the morphology of the underlying gold nanoparticle and the quality of the interface are the main drivers of photocatalytic performance. Herein, we show how we can synthesize TiO2-coated gold nanostar- and gold nanorod-based photocatalysts and identify the most important design parameters that one should be focusing on for the optimization of hot electron-based photocatalysts. In addition to nanoparticle morphology and interface quality, we determine that the integrated absorptivity of the plasmon band and the uniformity and crystallinity of the semiconductor shell are important, even though to a lesser extent. These results may prove interesting not only to increase production rates in hydrogen evolution reactions or other chemical conversions, but also to decouple and understand additional mechanisms driving photocatalysis, other than the sequential, hot electron mediated one, as we reported before.

Periodic, self-consistent generalized gradient approximation (GGA PW-91) density functional theory (DFT) was applied to study the effect of tin coverage in platinum–tin alloys in the dehydrogenation of ethane. Light alkane dehydrogenation to olefins can add significant value to hydrocarbon processes that generate ethane and propane by converting low value commodity fuels to high-value chemical and polymer precursors. Supported Pt catalysts are known to be active but show significant coke formation and deactivation, which can be reduced by alloying with Sn. Model surfaces of substitutional surface alloys of Pt and Sn were constructed with 1/4 and 1/2 of a monolayer of Pt atoms in the surface of fcc Pt(111) replaced by Sn atoms. Potential energy surfaces for all C1 and C2 derivatives from C–H and C–C bond cleavage from ethane were computed with kinetic reaction barriers obtained using the climbing-image nudged elastic band method. While the presence of Sn weakened the binding energies of all species, the ef...

The reactions of 1-pentene over acid zeolites were investigated in the liquid phase at 473 K. The primary reactions were isomerization, dimerization, and subsequent cracking of dimers. Zeolites consisting of only 10-membered (MFI) or 12-membered rings (FAU, BEA) behaved similarly, with dimerization and subsequent cracking products observed. Zeolites possessing 8-membered rings (MOR, FER) showed very different selectivity from each other and from other zeolites. MOR showed almost complete conversion of C 10 olefins, such that hexene and butene from cracking were the dominant products. FER showed high activity and selectivity for dimerization, with very small amounts of cracking products observed.

This paper presents the fundamental investigation on crack propagation rate (CPR) and Stress Intensity Factor (SIF) for a typical fatigue and welded specimens which are Compact Tension (CT) and Single Edge Notch Tension (SENT) as well as Butt and longitudinal T-joint. The material data of austenitic stainless steel SS316L was used to observe crack propagation rate with different initial crack length and different tensile load was used for the fracture mechanics investigation. The geometry of the specimens was modelled by using open source software CASCA while Franc 2D was used for post processing based on Paris Erdogan Law with different crack increment steps. The analysis of crack propagation using fracture mechanics technique requires an accurate calculation of the stress intensity factor SIF and comparison of the critical strength of the material (KIC) was used to determine the critical crack length of the specimens. it can be concluded that open source finite element method software can be used for predicting of fatigue life on simplified geometry.

Homocysteine (Hcy) is an independent risk factor for predisposing to atherosclerosis and endothelial dysfunction. Hcy levels increase with Vitamin B12 deficiency. The aim of this study was to investigate the association between carotid intima-media thickness (CIMT) and the autonomic modulation of heart rate variability (HRV) in early detection of atherosclerosis and impaired cardiac autonomic control in pediatric patients with Vitamin B12 deficiency.Sixty patients with Vitamin B12 deficiency (14.4 ± 1.72 years, 36 female) and 40, age, sex, and body mass index-matched healthy controls (13.4 ± 1.86 years, 24 female) had performed 24-h Holter monitoring, carotid ultrasonography, and echocardiography. Linear regression models assessed associations between to HRV parameters and CIMT and the blood markers.We defined Vitamin B12 deficiency as a serum level, 200 pg/mL. Hcy (P0.001) and CIMT (P0.001) levels were significantly higher in the patient group compared with the control group. Hcy level was found to be the most important independent variable affecting CIMT. Each 1 degree increase in Hcy, it was observed that the CIMT value increased by 0.01 mm (B = 0.01; t = -2.39; P0.05). Low-frequency power (LF), high-frequency power (HF) (P0.001), and the square root of the mean of the squared differences of two consecutive RR intervals (rMSSd) (P = 0.04) were significantly lower in the B12 deficient patients. Furthermore, Hcy level was found to be the most important independent variable affecting LF, HF, and rMSSd.Subclinical atherosclerosis was associated with cardiovascular autonomic imbalance in pediatric patients with Vitamin B12 deficiency. Homocysteinemia may be an important marker for the prediction of future cardiovascular disease.

Sinonasal adenocarcinomas are rare tumours, with three subtypes. They are mostly low-grade tumours, although they can also be aggressive. In this case report, we describe a 34-year-old patient with sinonasal adenocarcinomas. Within his nasal cavity was found an irregular mass. Given the intratumoral calcification and bone, the mass was thought to be a bone-producing tumour, such as an osteosarcoma. The pathological diagnosis was a sinonasal adenocarcinoma with extensive metaplastic bone. To the best of our knowledge, this is the first case of a sinonasal adenocarcinoma with metaplastic ossification.

Periodic, self-consistent DFT-GGA (PW91) calculations were used to study the interaction of hydrogen atoms with the (111) surfaces of substitutional near-surface alloys (NSAs) of Au and Ni with different surface layer compositions and different arrangements of Au atoms in the surface layer. The effect of hydrogen adsorption on the surface and in the first and second subsurface layers of the NSAs was studied. Increasing the Au content in the surface layer weakens hydrogen binding on the surface, but strengthens subsurface binding, suggesting that the distribution of surface and subsurface hydrogen will be different than that on pure Ni(111). While the metal composition of the surface layer has an effect on the binding energy of hydrogen on NSA surfaces, the local composition of the binding site has a stronger effect. For example, fcc hollow sites consisting of three Ni atoms bind H nearly as strongly as on Ni(111), and fcc sites consisting of three Au atoms bind H nearly as weakly as on Au(111). Sites with one or two Au atoms show intermediate binding energies. The preference of hydrogen for three-fold Ni hollow sites alters the relative stabilities of different surface metal atom arrangements, and may provide a driving force formore » adsorbate-induced surface rearrangement.« less