7 research outputs found

    Ambient effects on the electrical conductivity of carbon nanotubes

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    We show that the electrical conductivity of single walled carbon nanotubes (SWCNT) networks is affected by oxygen and air humidity under ambient conditions by more than a magnitude. Later, we intentionally modified the electrical conductivity by functionalization with iodine and investigated the changes in the band structure by optical absorption spectroscopy.Measuring in parallel the tubes electrical conductivity and optical absorption spectra, we found that conduction mechanism in SWCNT is comparable to that of intrinsically conducting polymers. We identified, in analogy to conducting polymers, in the infrared spectra a new absorption band which is responsible for the increased conductivity, leading to a closing gap in semiconducting SWCNT.We could show that by different functionalizations of the same SWCNT starting material the properties like conductivity can be dramatically changed, leading to different imaginable applications. We investigated here, an ultraviolet sensor with weakly modified SWCNT

    Dynamics of pulmonary hypertension severity in the first 48 h in neonates with prenatally diagnosed congenital diaphragmatic hernia

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    IntroductionPulmonary hypertension (PH) is one of the major contributing factors to the high morbidity and mortality in neonates with congenital diaphragmatic hernia (CDH). The severity and duration of postnatal PH are an established risk factor for patient outcome; however, the early postnatal dynamics of PH have not been investigated. This study aims to describe the early course of PH in CDH infants, and its relation to established prognostic markers and outcome measures.MethodsWe performed a monocentric retrospective review of neonates with prenatally diagnosed CDH, who received three standardized echocardiographic examinations at 2–6 h, 24, and 48 h of life. The degree of PH was graded as one of three categories: mild/no, moderate, or severe PH. The characteristics of the three groups and their course of PH over 48 h were compared using univariate and correlational analyses.ResultsOf 165 eligible CDH cases, initial PH classification was mild/no in 28%, moderate in 35%, and severe PH in 37%. The course of PH varied markedly based on the initial staging. No patient with initial no/mild PH developed severe PH, required extracorporeal membrane oxygenation (ECMO)-therapy, or died. Of cases with initial severe PH, 63% had persistent PH at 48 h, 69% required ECMO, and 54% died. Risk factors for any PH included younger gestational age, intrathoracic liver herniation, prenatal fetoscopic endoluminal tracheal occlusion (FETO)-intervention, lower lung to head ratio (LHR), and total fetal lung volume (TFLV). Patients with moderate and severe PH showed similar characteristics, except liver position at 24- (p = 0.042) and 48 h (p = 0.001), mortality (p = 0.001), and ECMO-rate (p = 0.035).DiscussionTo our knowledge, this is the first study to systematically assess the dynamics of PH in the first postnatal 48 h at three defined time points. CDH infants with initial moderate and severe PH have a high variation in postnatal PH severity over the first 48 h of life. Patients with mild/no PH have less change in PH severity, and an excellent prognosis. Patients with severe PH at any point have a significantly higher risk for ECMO and mortality. Assessing PH within 2–6 h should be a primary goal in the care for CDH neonates

    The combined prevalence of classified rare rheumatic diseases is almost double that of ankylosing spondylitis

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    Background!#!Rare diseases (RDs) affect less than 5/10,000 people in Europe and fewer than 200,000 individuals in the United States. In rheumatology, RDs are heterogeneous and lack systemic classification. Clinical courses involve a variety of diverse symptoms, and patients may be misdiagnosed and not receive appropriate treatment. The objective of this study was to identify and classify some of the most important RDs in rheumatology. We also attempted to determine their combined prevalence to more precisely define this area of rheumatology and increase awareness of RDs in healthcare systems. We conducted a comprehensive literature search and analyzed each disease for the specified criteria, such as clinical symptoms, treatment regimens, prognoses, and point prevalences. If no epidemiological data were available, we estimated the prevalence as 1/1,000,000. The total point prevalence for all RDs in rheumatology was estimated as the sum of the individually determined prevalences.!##!Results!#!A total of 76 syndromes and diseases were identified, including vasculitis/vasculopathy (n = 15), arthritis/arthropathy (n = 11), autoinflammatory syndromes (n = 11), myositis (n = 9), bone disorders (n = 11), connective tissue diseases (n = 8), overgrowth syndromes (n = 3), and others (n = 8). Out of the 76 diseases, 61 (80%) are classified as chronic, with a remitting-relapsing course in 27 cases (35%) upon adequate treatment. Another 34 (45%) diseases were predominantly progressive and difficult to control. Corticosteroids are a therapeutic option in 49 (64%) syndromes. Mortality is variable and could not be determined precisely. Epidemiological studies and prevalence data were available for 33 syndromes and diseases. For an additional eight diseases, only incidence data were accessible. The summed prevalence of all RDs was 28.8/10,000.!##!Conclusions!#!RDs in rheumatology are frequently chronic, progressive, and present variable symptoms. Treatment options are often restricted to corticosteroids, presumably because of the scarcity of randomized controlled trials. The estimated combined prevalence is significant and almost double that of ankylosing spondylitis (18/10,000). Thus, healthcare systems should assign RDs similar importance as any other common disease in rheumatology

    Therapeutic options for patients with rare rheumatic diseases: a systematic review and meta-analysis

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    Background!#!Rare diseases (RDs) in rheumatology as a group have a high prevalence, but randomized controlled trials are hampered by their heterogeneity and low individual prevalence. To survey the current evidence of pharmacotherapies for rare rheumatic diseases, we conducted a systematic review and meta-analysis. Randomized controlled trials (RCTs) of RDs in rheumatology for different pharmaco-interventions were included into this meta-analysis if there were two or more trials investigating the same RD and using the same assessment tools or outcome parameters. The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PUBMED were searched up to April 2nd 2020. The overall objective of this study was to identify RCTs of RDs in rheumatology, evaluate the overall quality of these studies, outline the evidence of pharmacotherapy, and summarize recommended therapeutic regimens.!##!Results!#!We screened 187 publications, and 50 RCTs met our inclusion criteria. In total, we analyzed data of 13 different RDs. We identified several sources of potential bias, such as a lack of description of blinding methods and allocation concealment, as well as small size of the study population. Meta-analysis was possible for 26 studies covering six RDs: Hunter disease, Behçet's disease, giant cell arteritis, ANCA-associated vasculitis, reactive arthritis, and systemic sclerosis. The pharmacotherapies tested in these studies consisted of immunosuppressants, such as corticosteroids, methotrexate and azathioprine, or biologicals. We found solid evidence for idursulfase as a treatment for Hunter syndrome. In Behçet's disease, apremilast and IF-α showed promising results with regard to total and partial remission, and Tocilizumab with regard to relapse-free remission in giant cell arteritis. Rituximab, cyclophosphamide, and azathioprine were equally effective in ANCA-associated vasculitis, while mepolizumab improved the efficacy of glucocorticoids. The combination of rifampicin and azithromycin showed promising results in reactive arthritis, while there was no convincing evidence for the efficacy of pharmacotherapy in systemic sclerosis.!##!Conclusion!#!For some diseases such as systemic sclerosis, ANCA-associated vasculitis, or Behcet's disease, higher quality trials were available. These RCTs showed satisfactory efficacies for immunosuppressants or biological drugs, except for systemic sclerosis. More high quality RCTs are urgently warranted for a wide spectrum of RDs in rheumatology

    Ductus arteriosus flow predicts outcome in neonates with congenital diaphragmatic hernia

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    ObjectiveTo investigate whether the pattern of flow through the ductus arteriosus (DA) is associated with the need for extracorporeal membrane oxygenation support (ECMO) or death in neonates with congenital diaphragmatic hernia (CDH). DesignRetrospective observational study. SettingGerman level III Neonatal Intensive Care Unit. ParticipantsOne hundred and nine CDH neonates were born between March 2009 and May 2021. MethodsDA flow pattern was assessed in echocardiograms obtained within 24 h of life by measuring flow time and velocity time integral (VTI) for both left-to-right (LR) and right-to-left (RL) components of the ductal shunt. A VTI ratio (VTILR/VTIRL) 33% were defined as markers of abnormal flow patterns. The primary outcome was the need for ECMO. The secondary outcome was death. ResultsSeventy-two patients (51.8%) had a VTI ratio 33%. Fifty-nine patients (42.4%) had an alteration of both values. Need for ECMO was present in 37.4% (n = 52), while 19.4% (n = 27) died. A VTI ratio <1.0 had the highest diagnostic accuracy for the need for ECMO, (sensitivity 82.7%, specificity 66.7%, negative predictive value [NPV] 86.6%, and positive predictive value [PPV] 59.7%) as well as for death (sensitivity 77.8%, specificity 54.5%, NPV 91.0%, and PPV 29.2%). Patients with VTI ratio <1.0 were 4.7 times more likely to need ECMO and 3.3 times more likely to die. VTI ratio values correlated significantly with pulmonary hypertension (PH) severity (r = -0.516, p < 0.001). ConclusionsA VTI ratio <1.0 is a valuable threshold to identify high-risk CDH neonates. For improved risk stratification, other parameters-for example, left ventricular cardiac dysfunction-should be combined with DA flow assessment
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