Evaluation of vascular graft infection following Bentall surgery using 18F-FDG PET/CT scan: A pediatric case report.

Key Clinical Message: After a Bentall surgery, there is a small chance of developing a serious complication called vascular graft infection. 18F-FDG PET/CT, a new and accurate diagnostic tool, can help detect it early, especially if the symptoms are unusual. Abstract: A 14-year-old boy who had undergone Bentall surgery 1 year prior presented with symptoms of fever, chills, loss of appetite, and weight loss over the course of a month. The initial Bentall surgery was performed due to an aneurysm of the thoracic aorta, along with severe aortic valve insufficiency and moderate aortic valve stenosis. The patient was referred to the PET/CT department for evaluation of possible endarteritis or infection of Dacron graft, which had been reported in trans-esophageal echocardiography as suspicious findings. Despite normal blood tests, blood cultures, and other imaging modalities, the 18F-FDG PET/CT confirmed the diagnosis of vascular graft infection. This diagnostic tool allowed for timely and appropriate treatment and prevention of possible complications.

Non-invasive current collectors for improved current-density distribution during CO2 electrolysis on super-hydrophobic electrodes.

Electrochemical reduction of CO2 presents an attractive way to store renewable energy in chemical bonds in a potentially carbon-neutral way. However, the available electrolyzers suffer from intrinsic problems, like flooding and salt accumulation, that must be overcome to industrialize the technology. To mitigate flooding and salt precipitation issues, researchers have used super-hydrophobic electrodes based on either expanded polytetrafluoroethylene (ePTFE) gas-diffusion layers (GDL's), or carbon-based GDL's with added PTFE. While the PTFE backbone is highly resistant to flooding, the non-conductive nature of PTFE means that without additional current collection the catalyst layer itself is responsible for electron-dispersion, which penalizes system efficiency and stability. In this work, we present operando results that illustrate that the current distribution and electrical potential distribution is far from a uniform distribution in thin catalyst layers (~50 nm) deposited onto ePTFE GDL's. We then compare the effects of thicker catalyst layers (~500 nm) and a newly developed non-invasive current collector (NICC). The NICC can maintain more uniform current distributions with 10-fold thinner catalyst layers while improving stability towards ethylene (≥ 30%) by approximately two-fold.

Comparing the role of 99m Tc-HYNIC-PSMA-11 and 99m Tc-MDP scintigraphy for the initial staging of intermediate to high-risk prostate cancer.

BACKGROUND: Although bone scintigraphy and abdominopelvic computed tomography (CT)/MRI have been the mainstay of initial staging in the intermediate to high-risk prostate cancer (PC) patients, prostate-specific membrane antigen (PSMA) PET/CT imaging provides promising additional value in the initial N/M staging of these patients in recent years. 99m Tc-PSMA scan is a new alternative to PSMA PET tracers with little evidence regarding its diagnostic value in the initial staging of PC. METHODS: This prospective study included 40 patients with newly diagnosed PC with initial intermediate or high-risk features [prostate-specific antigen (PSA) > 10 ng/dl, Gleason score ≥7 or stage cT2b and more]. All patients underwent both 99m Tc-methylene diphosphonate (MDP) bone scan and 99m Tc-HYNIC-PSMA-11 scan with maximum interval of 2 weeks. Abdominopelvic CT and MRI were also performed in this timeframe. Then, the results of these methods were compared with the final diagnosis data. RESULTS: Among the 40 included patients, 28 patients had finally been diagnosed as localized PC and 12 patients showed lymph node or metastatic involvement. The sensitivity, specificity and accuracy of 99m Tc-HYNIC-PSMA-11 vs. 99m Tc-MDP were 83.3% vs. 50.0%, 100% vs. 82.1% and 95% vs. 72.5%, respectively. However, when combined with the results of abdominopelvic CT/MRI the sensitivity reached 100% for both and the specificity raised to 100% and 96.4% for 99m Tc-HYNIC-PSMA-11 and 99m Tc-MDP, respectively. CONCLUSION: 99m Tc-HYNIC-PSMA-11 performs well in the initial staging of intermediate to high-risk PC and especially in low source areas without PET/CT it can be used as the first-line method of metastatic evaluation instead of bone scintigraphy. However, the combination and correlation of cross-sectional imaging is essential to gain the optimal diagnostic value.

Incidental Detection of Papillary Thyroid Carcinoma in Tc-99 m PSMA Imaging in a Case with Negative FNA Result.

Prostate-specific membrane antigen (PSMA) is a type II transmembrane glycoprotein and is expressed in multiple solid malignant neoplasms. We presented a case of a prostate cancer patient who went through Tc-99 m PSMA SPECT, and multifocal increased radiotracer uptake in the thyroid gland was demonstrated. Despite negative FNA results for malignancy, post-operative histopathologic examination illustrated papillary thyroid carcinoma.

Characterization of left ventricular diastolic parameters of gated-single-photon emission computed tomography myocardial perfusion imaging in patients with diabetes and normal myocardial perfusion and systolic function.

BACKGROUND: Diabetic cardiomyopathy is defined as an independent entity with a specified pathological progression from diastolic dysfunction with preserved ejection fraction to overt heart failure. Myocardial perfusion imaging (MPI) with gated-single-photon emission computed tomography (G-SPECT) has been introduced as a feasible tool to evaluate left ventricular (LV) diastolic function. The aim of this study was to investigate the characteristics of diastolic parameters derived from G-SPECT MPI in diabetic patients compared to patients at very low risk of coronary artery disease (CAD) and with no other CAD risk factors. METHODS: This cross-sectional study was performed on patients referred to the nuclear medicine department for G-SPECT MPI. Demographic and clinical data, as well as medical history, were extracted from a digital registry system including 4447 patients. Then, two matched groups of patients with only diabetes as cardiac risk factor ( n = 126) and those without any identifiable CAD risk factors ( n = 126) were selected. Diastolic parameters of MPI, including peak filling rate, time to peak filling rate, mean filling rate at the first third of diastole and second peak filling rate, were derived using quantitative software for eligible cases. RESULTS: The mean age of the diabetic and nondiabetic groups was 57.1 ± 14.9 and 56.7 ± 10.6 years, respectively ( P = 0.823). Comparison of quantitative SPECT MPI parameters between the two groups showed a statistically significant difference only in total perfusion deficit scores, whereas none of the functional parameters, including diastolic and dyssynchrony indices and the shape index, were significantly different. There were also no significant differences in diastolic function parameters between diabetes and nondiabetes patients in the age and gender subgroups. CONCLUSION: Based on the G-SPECT MPI findings, there is a comparable prevalence of diastolic dysfunction in patients with only diabetes as a cardiovascular risk factor and low-risk patients with no cardiovascular risk factors in the setting of normal myocardial perfusion and systolic function.

18F-FDG PET/CT imaging of several asymptomatic skeletal muscle metastases of mixed germ cell ovarian cancer.

Metastasis to muscles caused by ovarian cancer is very rare and has a poor prognosis. Performing a whole-body F18-FDG PET/CT scan makes it possible to examine the whole body in one study and detected lesions in unexpected places.

Geometric Catalyst Utilization in Zero-Gap CO2 Electrolyzers.

The electrochemical reduction of CO2 (CO2RR) on silver catalysts has been demonstrated under elevated current density, longer reaction times, and intermittent operation. Maintaining performance requires that CO2 can access the entire geometric catalyst area, thus maximizing catalyst utilization. Here we probe the time-dependent factors impacting geometric catalyst utilization for CO2RR in a zero-gap membrane electrode assembly. We use three flow fields (serpentine, parallel, and interdigitated) as tools to disambiguate cell behavior. Cathode pressure drop is found to play the most critical role in maintaining catalyst utilization at all time scales by encouraging in-plane CO2 transport throughout the gas-diffusion layer (GDL) and around salt and water blockages. The serpentine flow channel with the highest pressure drop is then the most failure-resistant, achieving a CO partial current density of 205 mA/cm2 at 2.76 V. These findings are confirmed through selectivity measurements over time, double-layer capacitance measurements to estimate GDL flooding, and transport modeling of the spatial CO2 concentration.

Electroreduction of Carbon Dioxide to Acetate using Heterogenized Hydrophilic Manganese Porphyrins.

The electrochemical reduction of carbon dioxide (CO2 ) to value-added chemicals is a promising strategy to mitigate climate change. Metalloporphyrins have been used as a promising class of stable and tunable catalysts for the electrochemical reduction reaction of CO2 (CO2 RR) but have been primarily restricted to single-carbon reduction products. Here, we utilize functionalized earth-abundant manganese tetraphenylporphyrin-based (Mn-TPP) molecular electrocatalysts that have been immobilized via electrografting onto a glassy carbon electrode (GCE) to convert CO2 with overall 94 % Faradaic efficiencies, with 62 % being converted to acetate. Tuning of Mn-TPP with electron-withdrawing sulfonate groups (Mn-TPPS) introduced mechanistic changes arising from the electrostatic interaction between the sulfonate groups and water molecules, resulting in better surface coverage, which facilitated higher conversion rates than the non-functionalized Mn-TPP. For Mn-TPP only carbon monoxide and formate were detected as CO2 reduction products. Density-functional theory (DFT) calculations confirm that the additional sulfonate groups could alter the C-C coupling pathway from *CO→*COH→*COH-CO to *CO→*CO-CO→*COH-CO, reducing the free energy barrier of C-C coupling in the case of Mn-TPPS. This opens a new approach to designing metalloporphyrin catalysts for two carbon products in CO2 RR.

Energy comparison of sequential and integrated CO2 capture and electrochemical conversion.

Integrating carbon dioxide (CO2) electrolysis with CO2 capture provides exciting new opportunities for energy reductions by simultaneously removing the energy-demanding regeneration step in CO2 capture and avoiding critical issues faced by CO2 gas-fed electrolysers. However, understanding the potential energy advantages of an integrated process is not straightforward due to the interconnected processes which require knowledge of both capture and electrochemical conversion processes. Here, we identify the upper limits of the integrated process from an energy perspective by comparing the working principles and performance of integrated and sequential approaches. Our high-level energy analyses unveil that an integrated electrolyser must show similar performance to the gas-fed electrolyser to ensure an energy benefit of up to 44% versus the sequential route. However, such energy benefits diminish if future gas-fed electrolysers resolve the CO2 utilisation issue and if an integrated electrolyser shows lower conversion efficiencies than the gas-fed system.

Advancing integrated CO2 electrochemical conversion with amine-based CO2 capture: a review.

Carbon dioxide (CO2) electrolysis is a promising route to utilise captured CO2 as a building block to produce valuable feedstocks and fuels such as carbon monoxide and ethylene. Very recently, CO2 electrolysis has been proposed as an alternative process to replace the amine recovery unit of the commercially available amine-based CO2 capture process. This process would replace the most energy-intensive unit operation in amine scrubbing while providing a route for CO2 conversion. The key enabler for such process integration is to develop an efficient integrated electrolyser that can convert CO2 and recover the amine simultaneously. Herein, this review provides an overview of the fundamentals and recent progress in advancing integrated CO2 conversion in amine-based capture media. This review first discusses the mechanisms for both CO2 absorption in the capture medium and electrochemical conversion of the absorbed CO2. We then summarise recent advances in improving the efficiency of integrated electrolysis via innovating electrodes, tailoring the local reaction environment, optimising operation conditions (e.g., temperatures and pressures), and modifying cell configurations. This review is concluded with future research directions for understanding and developing integrated CO2 electrolysers.

CO2 Electrolysis via Surface-Engineering Electrografted Pyridines on Silver Catalysts.

The electrochemical reduction of carbon dioxide (CO2) to value-added materials has received considerable attention. Both bulk transition-metal catalysts and molecular catalysts affixed to conductive noncatalytic solid supports represent a promising approach toward the electroreduction of CO2. Here, we report a combined silver (Ag) and pyridine catalyst through a one-pot and irreversible electrografting process, which demonstrates the enhanced CO2 conversion versus individual counterparts. We find that by tailoring the pyridine carbon chain length, a 200 mV shift in the onset potential is obtainable compared to the bare silver electrode. A 10-fold activity enhancement at -0.7 V vs reversible hydrogen electrode (RHE) is then observed with demonstratable higher partial current densities for CO, indicating that a cocatalytic effect is attainable through the integration of the two different catalytic structures. We extended the performance to a flow cell operating at 150 mA/cm2, demonstrating the approach's potential for substantial adaptation with various transition metals as supports and electrografted molecular cocatalysts.

Immobilization strategies for porphyrin-based molecular catalysts for the electroreduction of CO2.

The ever-growing level of carbon dioxide (CO2) in our atmosphere, is at once a threat and an opportunity. The development of sustainable and cost-effective pathways to convert CO2 to value-added chemicals is central to reducing its atmospheric presence. Electrochemical CO2 reduction reactions (CO2RRs) driven by renewable electricity are among the most promising techniques to utilize this abundant resource; however, in order to reach a system viable for industrial implementation, continued improvements to the design of electrocatalysts is essential to improve the economic prospects of the technology. This review summarizes recent developments in heterogeneous porphyrin-based electrocatalysts for CO2 capture and conversion. We specifically discuss the various chemical modifications necessary for different immobilization strategies, and how these choices influence catalytic properties. Although a variety of molecular catalysts have been proposed for CO2RRs, the stability and tunability of porphyrin-based catalysts make their use particularly promising in this field. We discuss the current challenges facing CO2RRs using these catalysts and our own solutions that have been pursued to address these hurdles.

Electrochemical Reduction of CO2: A Review of Cobalt Based Catalysts for Carbon Dioxide Conversion to Fuels.

Electrochemical CO2 reduction reaction (CO2RR) provides a promising approach to curbing harmful emissions contributing to global warming. However, several challenges hinder the commercialization of this technology, including high overpotentials, electrode instability, and low Faradic efficiencies of desirable products. Several materials have been developed to overcome these challenges. This mini-review discusses the recent performance of various cobalt (Co) electrocatalysts, including Co-single atom, Co-multi metals, Co-complexes, Co-based metal-organic frameworks (MOFs), Co-based covalent organic frameworks (COFs), Co-nitrides, and Co-oxides. These materials are reviewed with respect to their stability of facilitating CO2 conversion to valuable products, and a summary of the current literature is highlighted, along with future perspectives for the development of efficient CO2RR.

Homogeneous and heterogeneous molecular catalysts for electrochemical reduction of carbon dioxide.

Carbon dioxide (CO2) is a greenhouse gas whose presence in the atmosphere significantly contributes to climate change. Developing sustainable, cost-effective pathways to convert CO2 into higher value chemicals is essential to curb its atmospheric presence. Electrochemical CO2 reduction to value-added chemicals using molecular catalysis currently attracts a lot of attention, since it provides an efficient and promising way to increase CO2 utilization. Introducing amino groups as substituents to molecular catalysts is a promising approach towards improving capture and reduction of CO2. This review explores recently developed state-of-the-art molecular catalysts with a focus on heterogeneous and homogeneous amine molecular catalysts for electroreduction of CO2. The relationship between the structural properties of the molecular catalysts and CO2 electroreduction will be highlighted in this review. We will also discuss recent advances in the heterogeneous field by examining different immobilization techniques and their relation with molecular structure and conductive effects.

Advances in the synthesis, molecular architectures and potential applications of gemini surfactants.

Gemini surfactants have been the subject of intensive scrutiny by virtue of their unique combination of physical and chemical properties and being used in ordinary household objects to multifarious industrial processes. In this review, we summarize the recent developments of gemini surfactants, highlighting the classification of gemini surfactants based on the variation in headgroup polarity, flexibility/rigidity of spacer, hydrophobic alkyl chain and counterion along with potential applications of gemini surfactants, depicting the truly remarkable journey of gemini surfactants that has just come of age. We have focused on those objectives which will act as suitable candidates to take the field forward. The preceding information will permit us to estimate the effect of structural variation on the aggregation behavior of gemini surfactants for nanoscience and biological applications like antimicrobial, anti-fungal agent, better gene and drug delivery agent with low cytotoxicity and biodegradability, which makes them more advantageous for a number of technological processes and hence reduces the impact of these gemini surfactants on the environment.