On hypergroups of order at most 6

This thesis surveys recent results on hypergroups as defined by Frédéric Marty in [3] and [4] and their relation to association schemes as presented in [5]. We show that every association scheme is a hypergroup. Then, we compile a few general results on hypergroups needed for our investigation of hypergroups with three, four and six elements. From [1] and [7], we give examples of hypergroups that do not come from finite schemes and from no scheme at all. Our main result occurs when considering hypergroups S with six elements that have a non-normal closed subset T of order 2 with three cosets. Since such class of hypergroups is too large to be completely described, we investigate a subclass S determined in [7]. We found that at least four hypergroups in this class come from finite schemes. For such purposes, we use the Hanaki-Miyamoto Classification of Small Association Schemes; cf. [8]

Reabilitação da cobertura de edifício no Rio de Janeiro

O edifício Rio Paraná é uma construção de uso comercial, contendo mais de seiscentas salas de escritórios, o qual faz parte do patrimônio urbano edificado no centro da cidade do Rio de Janeiro. A edificação foi construída em estrutura de concreto armado, entre 1939 e 1945. Desde então a sua cobertura apresentou inúmeras anomalias. A dita cobertura foi originalmente formada por telhado, composto por sistema de telhas apoiadas em armação de madeiramento, sendo o dito sistema apoiado sobre laje de cobertura em concreto. Ao longo dos anos, tal sistema de cobertura mostrou-se deficiente devido às falhas de concepção, agressões por terceiros, perda de desempenho dos materiais de construção, precariedade em procedimentos de reabilitação aliada à ineficiência na gestão da manutenção predial. Como resultado, ocorreram infiltrações através dos elementos da cobertura com suas ações danosas à conservação do patrimônio das edificações, em especial agressões aos materiais de construção, incluindo o concreto, aço, madeiramento e revestimentos. Ao mesmo tempo, tal situação constituiu-se num risco aos bens contidos nas salas comerciais e à saúde das pessoas ali presentes. Entretanto, em 2004, os gestores da edificação resolveram intervir de forma técnica com relação à reabilitação da cobertura, por meio da contratação de equipe especializada a fim de realizar inspeções, seguidas de apresentação de parecer técnico contendo a solução para a completa reabilitação da cobertura. Assim sendo, o trabalho aborda os procedimentos realizados em 2004 para reabilitação da cobertura do edifício Rio Paraná, então com quase sessenta anos de existência, incluindo inspeções, análise e diagnóstico, projetos, seguido das intervenções para substituição do telhado danificado por laje impermeabilizada.Tópico 6: Patrimonio Urbano de los siglos XVIII al XX. Técnicas de Limpieza y de Conservación

PET/CT Imaging for Personalized Management of Infectious Diseases

Positron emission tomography combined with computed tomography (PET/CT) is a nuclear imaging technique which is increasingly being used in infectious diseases. Because infection foci often consume more glucose than surrounding tissue, most infections can be diagnosed with PET/CT using 2-deoxy-2-[18F]fluoro-D-glucose (FDG), an analogue of glucose labeled with Fluorine-18. In this review, we discuss common infectious diseases in which FDG-PET/CT is currently applied including bloodstream infection of unknown origin, infective endocarditis, vascular graft infection, spondylodiscitis, and cyst infections. Next, we highlight the latest developments within the field of PET/CT, including total body PET/CT, use of novel PET radiotracers, and potential future applications of PET/CT that will likely lead to increased capabilities for patient-tailored treatment of infectious diseases

Importance of Blood Glucose Management Before 18F-FDG PET/CT in 322 Patients with Bacteremia of Unknown Origin

We investigated the effects of blood glucose levels on the performance of 18F-FDG PET/CT for detecting an infection focus in patients with bacteremia. Methods: A total of 322 consecutive patients with bacteremia who underwent 18F-FDG PET/CT between 2010 and 2021 were included. Logistic regression analysis was performed to evaluate the association between finding a true-positive infection focus on 18FFDG PET/CT and blood glucose level, type of diabetes, and use of hypoglycemic medication. C-reactive protein, leukocyte count, duration of antibiotic treatment, and type of isolated bacteria were considered as well. Results: Blood glucose level (odds ratio, 0.76 per unit increase; P=,0.001) was significantly and independently associated with 18F-FDG PET/CT outcome. In patients with a blood glucose level between 3.0 and 7.9mmol/L (54-142mg/dL), the true-positive detection rate of 18F-FDG PET/CT varied between 61% and 65%, whereas in patients with a blood glucose level between 8.0 and 10.9mmol/L (144-196mg/dL), the true-positive detection rate decreased to 30%- 38%. In patients with a blood glucose level greater than 11.0mmol/L (200mg/dL), the true-positive detection rate was 17%. In addition to C-reactive protein (odds ratio, 1.004 per point increase; P = 0.009), no other variables were independently associated with 18F-FDG PET/CT outcome. Conclusion: In patients with moderate to severe hyperglycemia, 18F-FDG PET/CT was much less likely to identify the focus of infection than in normoglycemic patients. Although current guidelines recommend postponing 18F-FDG PET/CT only in cases of severe hyperglycemia with glucose levels greater than 11mmol/L (200mg/dL), a lower blood glucose threshold seems to be more appropriate in patients with bacteremia of unknown origin and other infectious diseases.</p

Limitations and Pitfalls of FDG-PET/CT in Infection and Inflammation

White blood cells activated by either a pathogen or as part of a systemic inflammatory disease are characterized by high energy consumption and are therefore taking up the glucose analogue PET tracer FDG avidly. It is therefore not surprising that a steadily growing body of research and clinical reports now supports the use of FDG PET/CT to diagnose a wide range of patients with non-oncological diseases. However, using FDG PET/CT in patients with infectious or inflammatory diseases has some limitations and potential pitfalls that are not necessarily as pronounced in oncology FDG PET/CT. Some of these limitations are of a general nature and related to the laborious acquisition of PET images in patients that are often acutely ill, whereas others are more disease-specific and related to the particular metabolism in some of the organs most commonly affected by infections or inflammatory disease. Both inflammatory and infectious diseases are characterized by a more diffuse and less pathognomonic pattern of FDG uptake than oncology FDG PET/CT and the affected organs also typically have some physiological FDG uptake. In addition, patients referred to PET/CT with suspected infection or inflammation are rarely treatment naïve and may have received varying doses of antibiotics, corticosteroids or other immune-modulating drugs at the time of their examination. Combined, this results in a higher rate of false positive FDG findings and also in some cases a lower sensitivity to detect active disease. In this review, we therefore discuss the limitations and pitfalls of FDG PET/CT to diagnose infections and inflammation taking these issues into consideration. Our review encompasses the most commonly encountered inflammatory and infectious diseases in head and neck, in the cardiovascular system, in the abdominal organs and in the musculoskeletal system. Finally, new developments in the field of PET/CT that may help overcome some of these limitations are briefly highlighted

Clinical implications of increased uptake in bone marrow and spleen on FDG-PET in patients with bacteremia

PURPOSE: To investigate which clinical factors and laboratory values are associated with high FDG uptake in the bone marrow and spleen on 2-deoxy-2-[18F]fluoro-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) in patients with bacteremia.METHODS: One hundred forty-five consecutive retrospective patients with bacteremia who underwent FDG-PET/CT between 2010 and 2017 were included. Mean standard uptake values (SUVmean) of FDG in bone marrow, liver, and spleen were measured. Bone marrow-to-liver SUV ratios (BLR) and spleen-to-liver SUV ratios (SLR) were calculated. Linear regression analyses were performed to examine the association of BLR and SLR with age, gender, hemoglobin, leukocyte count, platelets, glucose level, C-reactive protein (CRP), microorganism, days of antibiotic treatment before FDG-PET/CT, infection focus, use of immunosuppressive drugs, duration of hospital stay (after FDG-PET/CT), ICU admission, and mortality.RESULTS: C-reactive protein (p = 0.006), a cardiovascular or musculoskeletal focus of infection (p = 0.000 for both), and bacteremia caused by Gram-negative bacteria (p = 0.002) were independently and positively associated with BLR, while age (p = 0.000) and glucose level before FDG-PET/CT (p = 0.004) were independently and negatively associated with BLR. For SLR, CRP (p = 0.001) and a cardiovascular focus of infection (p = 0.020) were independently and positively associated with SLR, while age (p = 0.002) and glucose level before FDG-PET/CT (p = 0.016) were independently and negatively associated with SLR.CONCLUSION: High FDG uptake in the bone marrow is associated with a higher inflammatory response and younger age in patients with bacteremia. In patients with high FDG uptake in the bone marrow, a cardiovascular or musculoskeletal focus of infection is more likely than other foci, and the infection is more often caused by Gram-negative species. High splenic FDG uptake is associated with a higher inflammatory response as well, and a cardiovascular focus of infection is also more likely in case of high splenic FDG uptake.</p

The c2d Spitzer Spectroscopic Survey of Ices Around Low-Mass Young Stellar Objects. IV. NH3 and CH3OH

NH3 and CH3OH are key molecules in astrochemical networks leading to the formation of more complex N- and O-bearing molecules, such as CH3CN and HCOOCH3. Despite a number of recent studies, little is known about their abundances in the solid state. (...) In this work, we investigate the ~ 8-10 micron region in the Spitzer IRS (InfraRed Spectrograph) spectra of 41 low-mass young stellar objects (YSOs). These data are part of a survey of interstellar ices in a sample of low-mass YSOs studied in earlier papers in this series. We used both an empirical and a local continuum method to correct for the contribution from the 10 micron silicate absorption in the recorded spectra. In addition, we conducted a systematic laboratory study of NH3- and CH3OH-containing ices to help interpret the astronomical spectra. We clearly detect a feature at ~9 micron in 24 low-mass YSOs. Within the uncertainty in continuum determination, we identify this feature with the NH3 nu_2 umbrella mode, and derive abundances with respect to water between ~2 and 15%. Simultaneously, we also revisited the case of CH3OH ice by studying the nu_4 C-O stretch mode of this molecule at ~9.7 micron in 16 objects, yielding abundances consistent with those derived by Boogert et al. 2008 (hereafter paper I) based on a simultaneous 9.75 and 3.53 micron data analysis. Our study indicates that NH3 is present primarily in H2O-rich ices, but that in some cases, such ices are insufficient to explain the observed narrow FWHM. The laboratory data point to CH3OH being in an almost pure methanol ice, or mixed mainly with CO or CO2, consistent with its formation through hydrogenation on grains. Finally, we use our derived NH3 abundances in combination with previously published abundances of other solid N-bearing species to find that up to 10-20 % of nitrogen is locked up in known ices.Comment: 31 pages, 15 figures, accepted for publication in Ap