1,721,086 research outputs found
Hypothalamic-pituitary-adrenal axis impairment in the pathogenesis of rheumatoid arthritis and polymyalgia rheumatica.
No full textDynamic modeling and thermal management of a Power-to-Power system with hydrogen storage in microporous adsorbent materials
No full textThe increasing penetration of distributed renewable energy sources involves the development of efficient energy storage solutions. Hydrogen is a viable alternative, or complement, to electric batteries for long-term and high-capacity storage. This article assesses the benefits of hydrogen storage in microporous adsorption materials at room temperature. The integrated Power-to-Power system dynamic behavior is modelled. We assessed the system performance looking at hydrogen adsorption in four porous materials (MSC-30, IRMOF-1, NU-110, and C/Be2) at room temperature for high-storage capacity. Hydrogen storage in an empty pressurized vessel by means of mechanical compression only is evaluated for comparison of the previous cases. The best performance in terms of tank volume size and round-trip efficiency are obtained by adopting adsorbent materials as follows: C/Be2 > IRMOF-1 > NU-110 > MSC-30 > empty storage. Indeed, under the same operating conditions, the volume size of the storage tank is reduced by 38 to 88% compared to the empty vessel, and the round-trip efficiency gain ranges between 0.6 and 2.8 percentage points according to the properties of the adsorbent material. Finally, by filling the storage tank with adsorbent materials the DOE targets are met at a pressure from 45% (MSC-30) to 83% (C/Be2) lower than in an empty tank
Expedited access to β-lactams via a telescoped three-component Staudinger reaction in flow
No full textThe Staudinger reaction is widely used for the generation of β-lactams via the thermal cycloaddition of imines with ketenes. Traditionally, it cannot be performed as a multicomponent reaction between aldehydes, amines and ketenes, thus limiting its versatility. Recently we reported for the first time a three-component Staudinger reaction in batch, exploiting a photochemical Wolff rearrangement of diazoketones and an in situ generation of the imine. Here we report an expedited continuous flow approach that generates the crucial ketene intermediate prior to its telescoped reaction with an imine component at ambient temperatures. The imine is prepared by an in situ dehydration between amines and aldehydes in a packed bed reactor containing basic alumina as drying agent. The resulting telescoped flow approach features a fast dehydration reaction (tRes ca. 3 min) as well as an efficient Wolff rearrangement using LEDs (420 nm) to afford the desired β-lactam products in less than 30 min which compares favorably with reaction times of several days in batch mode. Flow processing thereby affords a safe and streamlined entry to these important targets and allows their effective generation on gram scale. Moreover, this approach exploits several homogeneous and heterogeneous transformations under mild conditions that generate water and nitrogen gas as the only by-products. Graphical abstract: (Figure presented.
Non-islet-cell tumor hypoglycemia in a dog associated with high levels of Insulin-like Growth Factor II
No full text
HYPOGLYCEMIA IN A DOG WITH A LEIOMYOMA OF THE GASTRIC WALL PRODUCING AN INSULIN-LIKE GROWTH-FACTOR II-LIKE PEPTIDE
No full textA 12-year-old mixed-breed male dog was referred to the Clinica Medica Veterinaria of Bologna University for recurrent episodes of seizures due to hypoglycemia with abnormally low plasma insulin levels (18 pmol/l). Resection of a large leiomyoma (780 g) of the gastric wall resulted in a permanent resolution of the hypoglycemic episodes. Insulin-like growth factors I and II (IGF-I and -II) were measured by RIA in serum before and after surgery and in tumor tissue, Results were compared to the serum concentration of 54 normal and to the tissue concentration observed in eight non-hypoglycemic dog gastric wall extracts, Before surgery, circulating immunoreactive IGF-I was 0.92 nmol/l, which is significantly lower than the control values (16.92+/-8.44 nmol/l, range 3.53-35.03), while IGF-II was 152 nmol/l, which is significantly higher than the control values (42.21+/-3.75, range 31.99-50.74). After surgery, IGF-I increased to 6.80 nmol/l while IGF-II decreased to 45.52 nmol/l. Tumor tissue IGF-II concentration was higher than normal (5.66 nmol/kg tissue as compared to a range in normal gastric wall tissue of 1.14-3.72 nmol/kg), while IGF-I was 0.08 nmol/kg tissue, which is close to the lowest normal value (range in controls, 0.08-1.18 nmol/kg). Partial characterization of IGF-II immunoreactivity extracted from tissue evidenced a molecular weight similar to that of mature IGF-II, thus excluding that peptide released by the tumor is a precursor molecule. In agreement with these data, at variance with samples of normal dog gastric wall, IGF-II immunostaining was positive and in situ hybridization evidenced the expression of IGF-II mRNA in tumor tissue specimen. Evaluation of the molecular distribution of the IGFs in the circulation evidenced that IGF-II immunoreactivity was predominantly in the 35-65 kD region and barely detectable in the other regions. These results show that in dog, non-islet cell tumor hypoglycemia, as demonstrated in humans, can be ascribed to overproduction of IGF-II circulating in a molecular form that can more easily cross the capillary wall, thus exerting its insulin-like effects on target tissues.[...
Secondary diabetes associated with principal endocrinopathies: the impact of new treatment modalities.
No full textThe secondary occurrence of type 2 diabetes with various hormonal diseases (e.g.
pituitary, adrenal and/or thyroid diseases) is a recurrent observation. Indeed,
impaired glucose tolerance (IGT) and overt diabetes mellitus are frequently
associated with acromegaly and hypercortisolism (Cushing syndrome). The increased
cardiovascular morbidity and mortality associated with acromegaly and Cushing
syndrome may partly be a consequence of increased insulin resistance that
normally accompanies hormone excess. Acromegalic patients are insulin resistant,
both in the liver and in the periphery, displaying hyperinsulinemia and increased
glucose turnover in the basal post-absorptive states. The prevalence of diabetes
mellitus and that of IGT in acromegaly is reported to range 16-56%, whereas the
degree of glucose tolerance seems correlated with circulating growth hormone (GH)
levels, age, and disease duration. Moreover, a family history of diabetes and
concomitant presence of arterial hypertension have been found to predispose to
diabetes as well. GH has physiological effects on glucose metabolism, stimulating
gluconeogenesis and lipolysis, which results in increased blood glucose and free
fatty acid levels. Conversely, insulin-like growth factor 1 (IGF-I) enhances
insulin sensitivity primarily on skeletal muscles. However, in acromegaly,
increased IGF-I levels are unable to counteract the insulin-resistance status
determined by GH excess. Therapy with somatostatin analogues (SSAs) induce
control of GH and IGF-I excess in the majority of patients, but their inhibitory
effect on pancreatic insulin secretion might complicate the overall effect of
this treatment on glucose tolerance. Hypercortisolism produces visceral obesity,
insulin resistance, and dyslipidemia that together with hypertension,
hypercoagulability, and ventricular morphologic and functional abnormalities
increase cardiovascular risk, and persist up to 5 years after resolution of
hypercortisolism. Hypercortisolism leads to hyperglycaemia and reduced glucose
tolerance, determines insulin resistance, stimulates hepatic gluconeogenesis and
glicogenolisis. In Cushing syndrome the prevalence of diabetes varies between 20
and 50%, but probably this prevalence is underestimated, as not always an oral
glucose tolerance test is performed in the presence of an apparently normal
fasting glycaemia. Again, disease duration, rather than hormone levels, seems to
be the major determinant in the occurrence of systemic complications in Cushing
syndrome. Due to the impact they have on mortality and morbidity in both
acromegaly and Cushing syndrome, these complications should be treated
aggressively. In patients with neuroendocrine tumours (NETs) the occurrence of
altered glucose tolerance may be due to a decreased insulin secretion, like it
happens in patients who underwent pancreatic surgery and in those with
pheochromocytoma, or to an altered counterbalance between hormones, such as in
patients with glucagonoma and somatostatinoma. Moreover, SSAs represent a valid
therapeutic choice in the symptomatic treatment of NETs, and also in this case
the medical therapy of the primary disease, may have a significant impact on the
prevalence of glucose metabolism imbalance. In thyroid disorders, an abnormal
glucose tolerance may be principally encountered in hyperthyroidism. The
pathogenesis is complex and scant data on prevalence and severity are found in
the literature. Adequate treatment for glucose imbalance is mandatory in these
peculiar patients in line with the American Diabetes Association and the European
Association for the Study of Diabetes consensus statement. In particular, since
traditional insulins have two features that may complicate therapy (absorption
profiles, delayed onset of action and peak activity), the new insulin analogues
could be of particular interest in the management of the secondary diabetes
associated with endocrinopathies, considering the frailty of these patients.
Indeed, it has been demonstrated that insulin glargine, given once daily, reduces
the risk of hypoglycaemia compared with other formulations, and can facilitate a
more aggressive insulin treatment in this class of patients
Digital Platforms for Renewable Energy Communities Projects: An Overview
Full text linkThe European Union energy policy agenda of achieving the transition to carbon neutrality has been established by an important legislative package called "Clean Energy for all Europeans". A novel approach introduced was to put the citizen at the center of the energy transition. On one side, by powering his freedom of action and, on the other side, by asking him an exceptional engagement in energy consumption reduction activities and in participating in the investments for new distributed Renewable Energy Sources (RES) power plants. The Renewable Energy Communities (REC) is the policy framework used to implement this strategy introduced by the Renewable Energy Directive Recast (RED II). In particular, RECs promote citizen’s active role by encouraging energy consumption reduction and energy demand flexibility while reducing the Not In My Bachyard (NIMBY) effect towards RES. Each member state is transposing the RED II directive, adapting it to national legislation and energy transition strategy. Pioneers countries like Italy have already started the experimentation of this framework and developing the first pilot projects. The citizens’ interest and their will to participate in REC projects indicate the need for supporting tools guiding them along all the project development stages: “design”, “creation”, and “operation”. This work presents three categories of supporting digital tools and platforms required to develop REC projects: Commercial, EU Founded and Freeware. We analyzed 30 tools, evaluating the services provided in each of the different stages of REC project implementation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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