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By offering promising solutions to two critical issues – the integration of renewable energies into energy systems and the decarbonization of existing hydrogen applications – green hydrogen production through water electrolysis is set to play a crucial role in addressing the major challenges of the energy transition. However, the successful integration of renewable energy sources relies on gaining accurate insights into the impacts that intermittent electrical supply conditions induce on electrolyzers. Despite the rising importance of addressing intermittency issues to accelerate the widespread adoption of renewable energy sources, the state-of-the-art lacks research providing an in-depth understanding of these concerns. This paper endeavors to offer a comprehensive review of existing research, focusing on proton exchange membrane (PEM) and alkaline electrolysis technologies operating under intermittent operation. Despite growing interest over the last ten years, the review underscores the scarcity of industrial-scale databases for quantifying these impacts. [Display omitted] • Dynamic features, e.g. event frequency and amplitude, affect efficiency and durability of alkaline and PEM electrolyzers. • Intermittent operation promotes electrolyzer decay, but literature lacks consensus and studies on alkaline technology. • Industrial-scale assessments of intermittency impacts are significantly lacking for both alkaline and PEM technologies. • Developing standardized methods is crucial to understand how intermittency affects electrolyzer efficiency and durability. [ABSTRACT FROM AUTHOR]

The increasing interest in leveraging green ammonia to mitigate carbon emissions in fertilizer production is paralleled by an expanding acknowledgment of its potential as a fuel for decarbonizing the electricity sector, particularly in high-efficiency gas turbine power plants. Co-firing ammonia with hydrogen presents a promising method for integrating ammonia into existing infrastructures. Within this context, the development of efficient technology for ammonia cracking presents a potential avenue for deploying ammonia in gas turbines. The objective of this study is to conduct a preliminary techno-economic evaluation and uncertainty analysis of two cracking technologies namely a membrane reactor and a conventional FTR (Fired Tubular Reactor) for the co-firing of ammonia with hydrogen in a CCGT (Combined Cycle Gas Turbine) plant. The integration of a membrane reactor during the cracking stage demonstrates a remarkable improvement in the system's thermal efficiency, surpassing traditional approaches by over 25%. Additionally, it brings about an approximate 10% reduction in the levelized cost of hydrogen (LCOH), despite a higher initial capital expenditure (CAPEX). At the CCGT level, the discrepancy in levelized cost of electricity (LCOE) narrows, as it is strongly influenced by the cost of ammonia constituting 80% of the LCOE. Beyond LCOE, the widespread adoption of these systems also faces challenges due to material scarcity. Analysis reveals that revamping just 1 GWe of CCGT assets using membrane reactors would for example necessitate approximately 0.11% of the global palladium supply, and 10% of the global ruthenium production. Considering the limited availability of these resources, coupled with their high demand across multiple sectors and the possibility of external factors such as geopolitical tensions, this strategy seems unfeasible. To tap into this market, future research should prioritize the exploration of alternative membrane materials, such as carbon molecular sieves, and catalysts, like nickel. • Two cracking technologies for NH3–H2 co-firing in CCGT plants have been evaluated. • Membrane reactors reduces H2 cost by 10% and raise efficiency by 25%. • The study indicates the need to explore new materials for this market (e.g. carbon molecular sieve membrane). [ABSTRACT FROM AUTHOR]

This review provides an exhaustive and comprehensive analysis of the existing modelling works about low temperature electrolysis system: alkaline and proton exchange membrane (PEM) technologies. In order to achieve this review, a classification was built, based on different criteria such as physical domains involved or modelling approaches. The proposed methodology allows both exposing an overview of the electrolysis system modelling field and providing a deep analysis of each reviewed model. Actual strengths, weaknesses and lacks in this research field are pointed out and the performed analysis provides ideas for future research in this area. [ABSTRACT FROM AUTHOR]

Proton exchange membrane (PEM) electrolysis technology appears as a key technology in the development of hydrogen-energy market applications such as energy storage or fuel for mobility. Its coupling with renewable electrical sources involves some issues related to the intermittent operation of PEM electrolysis systems. Within this framework, modelling is an essential tool to understand these issues, provide a thorough analysis and suggest some design optimization. A bibliographic analysis was carried out to identify existing models. State of the art highlighted that, although it is critical for the conception of such systems, only a few models take into account the dynamic of the whole system including balance of plant. Therefore, in this paper a new dynamic and multiphysic model of a proton exchange membrane electrolysis system is presented. It was first developed under a graphical modelling formalism: the bond graphs (BG). Regarding dynamic and multiphysic modelling of complex systems, the BG have many advantages: it involves four levels of modelling using only one tool; it is a unified multiphysic approach; the parameters used have a physical meaning; the BG model can be refined very easily by adding new elements without having to start again the modelling process. Finally, because of its causal and structural properties, BG is suitable for modelling but also for control, sizing and diagnosis analysis. The model was then transcribed systematically into block diagrams in modular fashion for reutilisability of model libraries components. After a validation process, the model was proved to describe accurately the dynamic behaviour of a semi-industrial PEM electrolysis system (25 kW). The dynamic model can now be used to achieve some analyses through BG structural properties and simulations. Thus, it is a powerful tool to improve the design of PEM electrolysis systems powered by intermittent electrical sources. [ABSTRACT FROM AUTHOR]

Objective Bilateral surgery has been largely advocated in premature boys with unilateral inguinal hernia owing to the high incidence of contralateral patent processus vaginalis. Recently, the potential morbidity of herniotomy in low birth-weight babies and the progress in pediatric anesthesia questioned this attitude. This study aims to evaluate the incidence of contralateral metachronous hernia in a large series of premature boys and to compare the morbidity of preventive versus elective surgery. Methods This retrospective multicenter analysis of 964 premature boys presenting with unilateral inguinal hernia operated from 1998 to 2012 included 557 infants who benefited from a unilateral herniotomy and 407 from a bilateral herniotomy (median follow-up 12 months). Results Contralateral metachronous hernia after unilateral surgery occurred in 11% (n = 60) without significant difference according to the initial symptomatic side (9.5% on right vs 13% on left, p > 0.05). Postoperative morbidity on the contralateral side was higher after preventive surgery than elective surgery with metachronous hernia (2.45% versus 0.9%, p = 0.05) especially for secondary cryptorchidism (1% vs 0%, p = 0.03). Despite the risk of metachronous incarcerated hernia, elective surgery did not increase the rate of testicular hypotrophy on the opposite side (0.7%, vs 0.7%, p > 0.05). Conclusion Systematic bilateral herniotomy is unnecessary in almost 90% of patients and has a significant morbidity. Secondary surgery for metachronous hernia does not increase the risk of testicular lesion and even reduces the risk of secondary cryptorchidism. These results, along with the risk of hypofertility reported after bilateral surgery, may justify treating only the symptomatic side in premature boys. [ABSTRACT FROM AUTHOR]

Summary: To delineate and compare the isokinetic neck strength profile of senior elite rugby players. One hundred and eighty-nine rugby players (mean; 95% confidence intervals: 24.31; 23.87–24.75 years) were sampled from South African provincial teams and assessed anthropometrically and isokinetically according to a set protocol. Specially designed equipment was used to perform the isokinetic assessment and gathered data were analysed according to positional categories (front, second, back row and backline players). Second row forwards performed the best in the measure of peak flexion (44.04; 40.41–47.67Nm) and lateral flexion right (69.42; 63.36–75.48Nm) and left (66.31; 61.21–71.41Nm) torque, while the front row forwards performed best in peak extension torque (65.60; 62.12–69.08Nm). Few significant differences (p <0.05) existed between the forward positional categories. However, they all proved to be significantly (p <0.05) stronger and more powerful than the backline players. Peak torque values relative to body weight indicated much less variability between all positional categories. Cervical flexor to extensor ratios showed that front row forwards (65; 61.94–68.06%) had significantly (p <0.05) lower ratios than the other positional categories. Absolute peak torque is an important positional prerequisite, especially among the front row forwards. Isokinetic neck strength data presented here provides a benchmark for the effective and quantified comparison of neck strength variables, assisting with preparticipation screening and the effective rehabilitation of injured senior rugby union players. [Copyright &y& Elsevier]

Background: Patient displacements and errors in R-wave detection are the main causes of inaccurate acquisition for gated single photon emission computed tomography (SPECT) and equilibrium radionuclide angiography (RNA). This study aimed to compare the influences of both factors between gated SPECT and RNA determinations of left ventricular ejection fraction.Methods and Results: On gated SPECT and RNA acquisitions, recorded in 20 patients with coronary artery disease, we simulated the consequences of (1) 3-dimensional patient displacements of low (6.7 mm), moderate (13.4 mm), and high amplitude (20.1 mm) and (2) an erroneous triggering on T waves in 10% to 40% of recorded beats. Absolute values of left ventricular ejection fraction changes from baseline were higher with gated SPECT compared with RNA for patient displacements of low amplitude (5.0% +/- 3.8% vs 1.2% +/- 0.9%, P < .001) or moderate amplitude (10.0% +/- 6.2% vs 3.0% +/- 2.3%, P = .001) but not for patient displacements of high amplitude (12% +/- 9% vs 9% +/- 7%, P = not significant) and inaccurate triggering (for 20% T-wave triggering, 8.9% +/- 3.6% vs 7.9% +/- 3.0%; P = not significant).Conclusion: Contrary to RNA, gated SPECT is vulnerable to small patient displacements, and thus, specific efforts might be useful for limiting this potential cause of erroneous results. Both techniques may be affected by low rates of triggering errors, suggesting that small acceptance windows on cycle length should be recommended not only for RNA but also for gated SPECT. [ABSTRACT FROM AUTHOR]

Background: Beta-blockers are potent anti-ischemic medications, able to improve prognosis in patients with coronary artery disease (CAD). However, it is not known whether beta-blockers have the same beneficial prognostic effect when residual ischemia persists on treatment.Methods and Results: The prognostic impact of exercise single photon emission computed tomography (SPECT) ischemia was analyzed in 442 patients with chronic CAD, who were treated with beta-blockers and who were referred to exercise thallium 201 SPECT, while they were receiving their daily-life medications. Ischemic and viable myocardium was documented on Tl-201 SPECT in 190 patients (43%), of whom only 23% had angina and only 26% had positive exercise testing results. During a follow-up of 3.8 +/- 1.7 years, 36 patients died and survival curves were progressively divergent between patients with and those without ischemic and viable myocardium: at 5 years, the respective survival rates were 81% +/- 4% and 94% +/- 2% (P =.004). By multivariate analysis, the best independent predictors of death were large extent of necrosis (>25% of left ventricle on Tl-201 SPECT, P <.001) and ischemic and viable myocardium (P =.001).Conclusions: In the CAD patients treated on a long-term basis with beta-blockers, survival is strongly influenced by persistent exercise SPECT ischemia on treatment. Therefore exercise SPECT on treatment could be a useful tool for selecting those who might benefit from additional anti-ischemic therapeutic interventions. [ABSTRACT FROM AUTHOR]

Summary: Background: Systemic sarcoidosis can result in dramatic manifestations despite therapeutic escalation. Tumor necrosis factor (TNFα) has a key role in this disease and antagonists of TNFα have been successfully used as an alternative to conventional therapy. We report a case of refractory sarcoidosis with mediastinal, bone and ear, nose, throat (ENT) lesions. Methods: In this patient we monitored response to treatment by infusions of the anti-TNFα antibody, infliximab, with fluorine 18-fluorodeoxyglucose positron emission tomography (FDG-PET). Results: Early and spectacular response to infliximab was demonstrated by FDG-PET, which evidenced complete response to treatment. Conclusion: This case supports use of FDG-PET to evaluate the extent of active disease in refractory sarcoidosis and above all, FDG-PET could be an imaging method of choice showing response to infliximab in refractory sarcoidosis earlier than other imaging techniques. [Copyright &y& Elsevier]

The article discusses a study that performed high-resolution simultaneous imaging of single photon emission computed tomography (SPECT), positron emission tomography (PET) and magnetic resonance imaging (MRI) tracers on histologic sections of myocardial infarction obtained from a rat. The images obtained are said to offer didactic insight into differences in the mechanisms by which the tracers enable viability assessment, including the gradual decrease in myocardial perfusion between remote, border and necrotic areas for sestamibi.

Abstract: The aim of our study was to compare whole-body MRI (Magnetic Resonance Imaging) with a multi-contrast protocol including a DW (Diffusion Weighted) sequence to PET-CT (Positron Emission Tomography) using 18FDG (18F-fluoroDeoxyGlucose) for staging advanced melanoma. In a first part, we compared the respective overall accuracy of each modality. We analyzed in a second part the benefits of a DW sequence added to the standard whole-body MRI protocol. Among the population of the 35 patients who experienced the two examinations of our prospective blinded study, we were able to detect 120 lesions and 70 of them were found malignant. The sensitivity and specificity for whole-body MRI were respectively 82% and 97%, while PET-CT reached 72.8% and 92.7%. DW sequence allowed the detection of 14 supplementary malignant lesions (20%) in comparison with standard MRI protocol. Moreover, this technique has been shown to be the most accurate for detecting metastases in the liver, bone, subcutaneous and intra-peritoneal sites. Consequently, a DW sequence should be added systematically to the standard whole-body MRI oncologic protocol because of its high added-value for metastasis detection. [Copyright &y& Elsevier]

Abstract: Only about 40 cases of septic arthritis of the facet joints have been reported to date. We report 6 new cases including 2 at the cervical spine, which is rarely involved. Mean age was 61.5 years; there were 5 men and 1 woman. Spinal pain and stiffness, fever, and asthenia were the presenting manifestations. Laboratory tests consistently showed inflammation. Among classical risk factors for infection, only noninsulin-dependent diabetes was noted, in a single patient. Mean time to the diagnosis was 42 days. Discitis, a far more common condition, was considered initially, and early radiographs were of limited diagnostic assistance. Radionuclide bone scans identified the site of the infection and served to look for other foci. Magnetic resonance imaging was effective in confirming the diagnosis at an early stage and in looking for local spread (muscles, epidural space, and disk). L3–L4 was involved in 3 patients, C4–C5 in 2, and L4–L5 in 1. Direct inoculation during mesotherapy sessions was the cause in 1 patient. Cultures of blood and needle biopsy samples were positive in all 6 cases; Staphylococcus aureus was the causative agent in 3 patients. The risk of local and systemic complications governs the prognosis of facet joint infection. Of our 6 patients, 4 experienced complications: there was 1 case each of discitis, epidural infection, endocarditis, and septic arthritis of the acromioclavicular joint. Fatal multiple organ dysfunction occurred in 1 patient. In the other 5 patients, antimicrobial therapy and protection from weight-bearing for 3 months ensured a favorable outcome. [Copyright &y& Elsevier]

Résumé: L’arthrite septique des articulations inter-apophysaires postérieures est rarement décrite dans la littérature, puisque seule une quarantaine de cas sont rapportés à ce jour. Cependant, nous présentons six nouvelles observations, dont deux localisations inhabituelles au rachis cervical. Les patients présentaient douleurs et raideur rachidiennes, fièvre et asthénie. Le premier diagnostic évoqué était une spondylodiscite, compte tenu de sa fréquence plus élevée. Cinq hommes et une femme, âgés en moyenne de 61,5 ans ont été affectés. Parmi les facteurs de risque classiquement décrits, seul un diabète non insulinodépendant a été retrouvé chez un patient. Les marqueurs biologiques de l’inflammation étaient constamment élevés. Le diagnostic est fait avec retard (42 jours) et le bilan radiographique initial est peu contributif. La scintigraphie osseuse permet de localiser l’atteinte septique et de détecter d’autres localisations. L’IRM confirme le diagnostic précocement et recherche des complications locales (pyomyosite, épidurite et spondylodiscite). L’atteinte L3-L4 est la plus fréquente (n =3), suivi de C4-C5 (n =2) et L4-L5 (n =1). Dans un cas, il s’agissait d’une contamination directe à la suite d’un traitement par mésothérapie. Les hémocultures et ponction-biopsies ont permis d’identifier l’agent pathogène dans tous les cas (Staphylococcus aureus dans 50%). La sévérité de cette pathologie réside dans ses possibles complications locales et systémiques, observées chez quatre de nos patients : spondylodiscite, épidurite, endocardite et arthrite septique de l’articulation acromioclaviculaire. Hormis le décès d’un patient par défaillance multiviscérale, tous les patients se sont améliorés progressivement sous traitement antibiotique et décharge pendant trois mois. [Copyright &y& Elsevier]

Objectives: A Phase III randomized trial was designed to assess the effectiveness of samarium-153 (153Sm)-lexidronam for palliation of bone pain in patients with hormone-refractory prostate cancer.Methods: A total of 152 men with hormone-refractory prostate cancer and painful bone metastases were enrolled in a prospective, randomized, double-blind trial comparing radioactive (153Sm) versus nonradioactive (152Sm) lexidronam complexes. Patients were randomized (2:1) to the radioactive (153Sm) agent. Patient diaries recording daily pain and analgesic use were completed during a planned 16-week evaluation period. Nonresponders were informed of the treatment received after 4 weeks of treatment and, if initially treated with placebo, were allowed to receive 153Sm-lexidronam in an open-label fashion. Pain was measured using validated patient-derived visual analog scales and pain descriptor scales.Results: 153Sm-lexidronam had positive effects on measures of pain relief compared with placebo within 1 to 2 weeks. Reductions in opioid use were recorded at weeks 3 and 4. Because nonresponders were unblinded at week 4, statistical comparisons between the arms beyond week 4 were not possible. Mild, transient bone marrow suppression was the only adverse event associated with 153Sm-lexidronam administration. The mean nadir white blood cell and platelet count (3 to 4 weeks after treatment) was 3800/μL and 127,000/μL, respectively. Counts recovered to baseline after approximately 8 weeks. No grade 4 decreases in either platelets or white bloods cells were documented.Conclusions: These findings demonstrate that 1 mCi/kg 153Sm-lexidronam is both safe and effective for the palliation of painful bone metastases in patients with hormone-refractory prostate cancer. [Copyright &y& Elsevier]

: ObjectivesThis study sought to identify determinants of the exercise rise in plasma levels of cardiac natriuretic peptides (NPs) in patients with coronary artery disease (CAD).: BackgroundDuring stress, there is a variable rise in the plasma level of NPs, but this rise frequently reaches levels that are known to lower the cardiac load and that thus might be beneficial to CAD patients.: MethodsPlasma venous concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were determined at rest and peak exercise in 104 patients with chronic CAD who were referred to exercise thallium-201 (201Tl) single-photon emission computed tomography (SPECT) and radionuclide angiography.: ResultsThe extent of scarred myocardium by 201Tl-SPECT and patient age were the best independent predictors of NP concentrations at rest, but also of increases in NP concentration during exercise (all p < 0.001). Moreover, beta-blocking treatment was an additional and strong independent predictor of the increase in NP concentrations at exercise (p < 0.001 for ANP; p = 0.001 for BNP). On average, exercise increases in NP concentrations were more than twice as high in patients with (n = 55) than in those without (n = 49) beta-blocker treatment (ANP: +49 ± 63 vs. +22 ± 25 ng/l, p = 0.01; BNP: +24 ± 5 vs. +11 ± 15 ng/l, p = 0.04), whereas NP concentrations at rest were equivalent in the two groups (ANP: 34 ± 34 vs. 30 ± 33 ng/l, p = NS; BNP: 85 ± 152 vs. 57 ± 101 ng/l, p = NS).: ConclusionsPatients with chronic CAD exhibit much higher exercise releases of ANP and BNP when they are treated with beta-blockers. This enhanced secretion of potent vasodilating and natriuretic agents constitutes an original therapeutic mechanism for further protecting diseased hearts against stress. [Copyright &y& Elsevier]