344 research outputs found
On totally geodesic submanifolds in the Jacobian locus
We study submanifolds of A_g that are totally geodesic for the locally
symmetric metric and which are contained in the closure of the Jacobian locus
but not in its boundary. In the first section we recall a formula for the
second fundamental form of the period map due to Pirola, Tortora and the first
author. We show that this result can be stated quite neatly using a line bundle
over the product of the curve with itself. We give an upper bound for the
dimension of a germ of a totally geodesic submanifold passing through [C] in
M_g in terms of the gonality of C. This yields an upper bound for the dimension
of a germ of a totally geodesic submanifold contained in the Jacobian locus,
which only depends on the genus. We also study the submanifolds of A_g obtained
from cyclic covers of the projective line. These have been studied by various
authors. Moonen determined which of them are Shimura varieties using deep
results in positive characteristic. Using our methods we show that many of the
submanifolds which are not Shimura varieties are not even totally geodesic.Comment: To appear on International Journal of Mathematic
On some differential-geometric aspects of the Torelli map
In this note we survey recent results on the extrinsic geometry of the
Jacobian locus inside . We describe the second fundamental form
of the Torelli map as a multiplication map, recall the relation between totally
geodesic subvarieties and Hodge loci and survey various results related to
totally geodesic subvarieties and the Jacobian locus.Comment: To appear on Boll. UMI, special volume in memory of Paolo de
Bartolomei
Conceptual design of PrandtlPlane civil transport aircraft
According to aircraft manufacturers and several air transportation players, the main challenge the civil aviation will have
to deal with in the future is to provide a sustainable growth strategy, in order to face the growing demand of air traffic all
over the world. The sustainability requirements are related to air pollution, noise impact, airport congestion, competitiveness
of the air transportation systems in terms of travel time and passengers’ comfort. Among the possible ways to
allow a sustainable growth of the air transportation systems, disruptive aircraft configurations have been object of study
for several years, in order to demonstrate that the improvement of aircraft performance can enable the envisaged
growth. This paper presents the study of a possible novel configuration called ‘‘PrandtlPlane,’’ having a box-wing layout
derived from Prandtl’s ‘‘Best Wing System’’ concept. The paper deals with the definition of top level requirements and
faces the conceptual study of the overall configuration, focusing on fuselage sizing as well as on the aerodynamic design of
the box-wing system. This latter is designed through an optimization-driven strategy, carried out by means of a low fidelity
aerodynamic tool, which simulates the flow condition in the subsonic range and introduces correction to take the
transonic effects into account. Design procedures and tools are presented, showing preliminary results related to a
PrandtlPlane compliant with ICAO Aerodrome Reference Code ‘‘C’’ standard, such as Airbus A320 and Boeing 737,
whose wingspan is limited to 36 m. Activities and results here shown are part of the first phase of the research project
‘‘PARSIFAL’’ (Prandtlplane ARchitecture for the Sustainable Improvement of Future AirpLanes), funded by the European
Commission under the Horizon 2020 Program, which aims to demonstrate that the PrandtlPlane configuration can
improve aircraft payload capability, keeping their dimensions compatible with present airport infrastructures
Dietary energy density: a mediator of depressive symptoms and abdominal obesity or independent predictor of abdominal obesity?
BACKGROUND: In the U.S., Europe, and throughout the world, abdominal obesity prevalence is increasing. Depressive symptoms may contribute to abdominal obesity through the consumption of diets high in energy density. PURPOSE: To test dietary energy density ([DED]; kilocalories/gram of food and beverages consumed) for an independent relationship with abdominal obesity or as a mediator between depressive symptoms and abdominal obesity. METHODS: This cross-sectional study included 87 mid-life, overweight adults; 73.6% women; 50.6% African-American. Variables and measures: Beck Depression Inventory-II (BDI-II) to measure depressive symptoms; 3-day weighed food records to calculate DED; waist circumference, an indicator of abdominal obesity. Hierarchical regression tested if DED explained waist circumference variance while controlling for depressive symptoms and consumed food and beverage weight. Three approaches tested DED as a mediator. RESULTS: Nearly three-quarters of participants had abdominal obesity, and the mean waist circumference was 103.2 (SD 14.3) cm. Mean values: BDI-II was 8.67 (SD 8.34) which indicates most participants experienced minimal depressive symptoms, and 21.8% reported mild to severe depressive symptoms (BDI-II ≥ 14); DED was 0.75 (SD 0.22) kilocalories/gram. Hierarchical regression showed an independent association between DED and waist circumference with DED explaining 7.0% of variance above that accounted for by BDI-II and food and beverage weight. DED did not mediate between depressive symptoms and abdominal obesity. CONCLUSIONS: Depressive symptoms and DED were associated with elevated waist circumference, thus a comprehensive intervention aimed at improving depressive symptoms and decreasing DED to reduce waist circumference is warranted
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Plasma Metabolomics in Human Pulmonary Tuberculosis Disease: A Pilot Study
We aimed to characterize metabolites during tuberculosis (TB) disease and identify new pathophysiologic pathways involved in infection as well as biomarkers of TB onset, progression and resolution. Such data may inform development of new anti-tuberculosis drugs. Plasma samples from adults with newly diagnosed pulmonary TB disease and their matched, asymptomatic, sputum culture-negative household contacts were analyzed using liquid chromatography high-resolution mass spectrometry (LC-MS) to identify metabolites. Statistical and bioinformatics methods were used to select accurate mass/charge (m/z) ions that were significantly different between the two groups at a false discovery rate (FDR) of q<0.05. Two-way hierarchical cluster analysis (HCA) was used to identify clusters of ions contributing to separation of cases and controls, and metabolomics databases were used to match these ions to known metabolites. Identity of specific D-series resolvins, glutamate and Mycobacterium tuberculosis (Mtb)-derived trehalose-6-mycolate was confirmed using LC-MS/MS analysis. Over 23,000 metabolites were detected in untargeted metabolomic analysis and 61 metabolites were significantly different between the two groups. HCA revealed 8 metabolite clusters containing metabolites largely upregulated in patients with TB disease, including anti-TB drugs, glutamate, choline derivatives, Mycobacterium tuberculosis-derived cell wall glycolipids (trehalose-6-mycolate and phosphatidylinositol) and pro-resolving lipid mediators of inflammation, known to stimulate resolution, efferocytosis and microbial killing. The resolvins were confirmed to be RvD1, aspirin-triggered RvD1, and RvD2. This study shows that high-resolution metabolomic analysis can differentiate patients with active TB disease from their asymptomatic household contacts. Specific metabolites upregulated in the plasma of patients with active TB disease, including Mtb-derived glycolipids and resolvins, have potential as biomarkers and may reveal pathways involved in TB disease pathogenesis and resolution
Transmesocolic Hernia of the Ascending Colon with Intestinal Obstruction
An internal hernia may be either congenital or acquired. The reported incidence of such hernias is 1–2%. In rare cases, internal hernias are the cause of small bowel obstruction, with a reported incidence of 0.2–0.9%. Transmesocolic hernia of the ascending colon is especially rare. We report a case of transmesocolic hernia of the ascending colon with intestinal obstruction diagnosed preoperatively. A 91-year-old Japanese female was admitted to our hospital with abdominal distention and vomiting of 3 days duration. She had no past history of any abdominal surgery. Abdominal examination revealed distention and tenderness in the right iliac fossa. Abdominal computed tomography revealed ileus in the sac at the left side of the ascending colon and dilatation of the oral side of the intestine. We diagnosed a transmesocolic hernia of the ascending colon with intestinal obstruction and performed emergency surgery. At the time of operation, there was internal herniation of ileal loops through a defect in the ascending mesocolon, without any strangulation of the small bowel. The contents were reduced and the tear in the ascending mesocolon was closed. The postoperative course was uneventful and the patient was discharged 14 days after surgery. In conclusion, preoperative diagnosis of bowel obstruction caused by a congenital mesocolic hernia remains difficult despite the techniques currently available, so it is important to consider the possibility of a transmesocolic hernia when diagnosing a patient with ileus with no past history of abdominal surgery
Allergic proctocolitis refractory to maternal hypoallergenic diet in exclusively breast-fed infants: a clinical observation
<p>Abstract</p> <p>Background</p> <p>Allergic proctocolitis (APC) in exclusively breast-fed infants is caused by food proteins, deriving from maternal diet, transferred through lactation. In most cases a maternal cow milk-free diet leads to a prompt resolution of rectal bleeding, while in some patients a multiple food allergy can occur. The aim of this study was to assess whether the atopy patch test (APT) could be helpful to identify this subgroup of patients requiring to discontinue breast-feeding due to polisensitization. Additionally, we assessed the efficacy of an amino acid-based formula (AAF) when multiple food allergy is suspected. amino acid-based formula</p> <p>Methods</p> <p>We have prospectively enrolled 14 exclusively breast-fed infants with APC refractory to maternal allergen avoidance. The diagnosis was confirmed by endoscopy with biopsies. Skin prick tests and serum specific IgE for common foods, together with APTs for common foods plus breast milk, were performed. After a 1 month therapy of an AAF all patients underwent a follow-up rectosigmoidoscopy.</p> <p>Results</p> <p>Prick tests and serum specific IgE were negative. APTs were positive in 100% infants, with a multiple positivity in 50%. Sensitization was found for breast milk in 100%, cow's milk (50%), soy (28%), egg (21%), rice (14%), wheat (7%). Follow-up rectosigmoidoscopy confirmed the remission of APC in all infants.</p> <p>Conclusions</p> <p>These data suggest that APT might become a useful tool to identify subgroups of infants with multiple gastrointestinal food allergy involving a delayed immunogenic mechanism, with the aim to avoid unnecessary maternal dietary restrictions before discontinuing breast-feeding.</p
Canakinumab as first-line biological therapy in Still’s disease and differences between the systemic and the chronic-articular courses: real-life experience from the international AIDA registry
Objective: Interleukin (IL)-1 inhibitors are largely employed in patients with Still’s disease; in cases with refractory arthritis, IL-6 inhibitors have shown to be effective on articular inflammatory involvement. The aim of the present study is to assess any difference in the effectiveness of the IL-1β antagonist canakinumab prescribed as first-line biologic agent between the systemic and the chronic-articular Still’s disease. Methods: Data were drawn from the retrospective phase of the AutoInflammatory Disease Alliance (AIDA) international registry dedicated to Still’s disease. Patients with Still’s disease classified according to internationally accepted criteria (Yamaguchi criteria and/or Fautrel criteria) and treated with canakinumab as first-line biologic agent were enrolled. Results: A total of 26 patients (17 females, 9 males; 18 patients developing Still’s disease after the age of 16 years) were enrolled; 16 (61.5%) patients suffered from the systemic pattern of the disease; 10 (38.5%) patients suffered from the chronic-articular type. No differences were observed between the systemic and the chronic-articular Still’s disease in the frequency of complete response, of flares after the start of canakinumab (p = 0.701) and in the persistence in therapy (p = 0.62). No statistical differences were observed between the two groups after 3 months, 12 months and at the last assessment in the decrease of: the systemic activity score (p = 0.06, p = 0.17, p = 0.17, respectively); the disease activity score on 28 joints (p = 0.54, p = 0.77, p = 0.98, respectively); the glucocorticoid dosage (p = 0.15, p = 0.50, and p = 0.50, respectively); the use of concomitant disease modifying anti-rheumatic drugs (p = 0.10, p = 1.00, and p = 1.00, respectively). No statistically significant differences were observed in the decrease of erythrocyte sedimentation rate (p = 0.34), C reactive protein (p = 0.48), and serum ferritin levels (p = 0.34) after the start of canakinumab. Conclusion: Canakinumab used for Still’s disease has been effective in controlling both clinical and laboratory manifestations disregarding the type of disease course when used as first-line biotechnological agent. These excellent results might have been further enhanced by the early start of IL-1 inhibition
DNA methylation patterns of Brachypodium distachyon chromosomes and their alteration by 5-azacytidine treatment
Sequential immunolocalisation of 5-methylcytosine (5-MeC) and fluorescence in situ hybridisation with chromosome-specific BAC clones were performed on Brachypodium distachyon mitotic metaphase chromosomes to determine specific DNA methylation patterns of each chromosome in the complement. In the majority of cells examined, chromosomes Bd4 and Bd5, which bear the loci of 5S and 35S ribosomal DNA, respectively, had characteristic 5-MeC patterns. In contrast, the distribution of 5-MeC along the metacentric chromosome pairs Bd1, Bd2 and Bd3 was more variable. There were numerous differences in distribution of methylated sites between homologous chromosomes as well as between chromosome arms. Some chromosome sites, such as pericentromeric regions, were highly methylated in all chromosomes. Additionally, the influence of a hypomethylating agent, 5-azacytidine, on B. distachyon chromosome methylation patterns was confirmed. It was found that some chromosome pairs underwent demethylation more easily than others, but there was no apparent regularity in demethylation of particular chromosome segments
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