81 research outputs found
Steiner representations of hypersurfaces
Let be an integral hypersurface of degree .
We show that each locally Cohen-Macaulay instanton sheaf on
with respect to in the
sense of Definition 1.3 in arXiv:2205.04767 [math.AG] yields the existence of
Steiner bundles and on of the same
rank and a morphism such
that the form defining to the power is exactly
. We inspect several examples for low values of , and
. In particular, we show that the form defining a
smooth integral surface in is the pfaffian of some skew-symmetric
morphism , where
is a suitable Steiner bundle on of sufficiently large even rank.Comment: 26 page
Even and odd instanton bundles on Fano threefolds
We define non-ordinary instanton bundles on Fano threefolds extending the
notion of (ordinary) instanton bundles. We determine a lower bound for the
quantum number of a non-ordinary instanton bundle, i.e. the degree of its
second Chern class, showing the existence of such bundles for each admissible
value of the quantum number when or , is
cyclic and is ordinary. In these cases we deal with the component inside
the moduli spaces of simple bundles containing the vector bundles we construct
and we study their restriction to lines. Finally we give a monadic description
of non-ordinary instanton bundles on and the smooth quadric
studying their loci of jumping lines, when of the expected codimension.Comment: 34 pages. Minor changes. The final version will appear in The Asian
Journal of Mathematic
On varieties with Ulrich twisted conormal bundles
We study varieties such that is is an Ulrich
vector bundle for some integer . We first prove that such an must be a
curve. Then we give several examples of curves with an Ulrich vector
bundle
X-ray emission from GPS/CSS sources
The high spatial resolution of the Chandra X-ray Observatory allows us to
study the environment of GPS/CSS sources to within an arcsec of the strong
compact core. We present the discovery of X-ray jets in two GPS quasars,
PKS1127-145 and B2 0738+393, indicating that X-ray emission associated with the
relativistic plasma is present at large distances from the GPS nucleus. We also
discuss first results from Chandra observations of our GPS/CSS sample. We find
that 6 out of 10 sources show intrinsic absorption at a level which may be
sufficient to confine the GPS source.Comment: contribution to the Third Workshop on CSS/GPS Radio Sources,
Kerastari, Greece, May 2002. Published in PASA, 2003 vol 20, p.11
Impact of a Shorter Brine Soaking Time on Nutrient Bioaccessibility and Peptide Formation in 30-Months-Ripened Parmigiano Reggiano Cheese
Reducing the salt content in food is an important nutritional strategy for decreasing the risk of diet-related diseases. This strategy is particularly effective when applied to highly appreciated food having good nutritional characteristics, if it does not impact either upon sensory or nutritional properties of the final product. This work aimed at evaluating if the reduction of salt content by decreasing the brine soaking time modifies fatty acid and protein bioaccessibility and bioactive peptide formation in a 30-month-ripened Parmigiano Reggiano cheese (PRC). Hence, conventional and hyposodic PRC underwent in vitro static gastrointestinal digestion, and fatty acid and protein bioaccessibility were assessed. The release of peptide sequences during digestion was followed by LC–HRMS, and bioactive peptides were identified using a bioinformatic approach. At the end of digestion, fatty acid and protein bioaccessibility were similar in conventional and hyposodic PRC, but most of the bioactive peptides, mainly the ACE-inhibitors, were present in higher concentrations in the low-salt cheese. Considering that the sensory profiles were already evaluated as remarkably similar in conventional and hyposodic PRC, our results confirmed that shortening brine soaking time represents a promising strategy to reduce salt content in PRC
Comparison of triple-lumen central venous catheters impregnated with silver nanoparticles (AgTive®) vs conventional catheters in intensive care unit patients
BACKGROUND:
Silver-impregnated central venous catheters (CVCs) have been proposed as a means for preventing CVC colonization and related bloodstream infections (CRBSIs).
AIM:
To evaluate the efficacy of CVCs impregnated with silver nanoparticles in a large group of critically ill patients.
METHODS:
A prospective, randomized clinical trial was conducted in five intensive care units (ICUs). Three hundred and thirty-eight adult patients requiring CVCs between April 2006 and November 2008 were randomized to receive AgTive silver-nanoparticle-impregnated (SC) or conventional (CC) CVCs. Primary endpoints were CVC colonization (growth of ≥15 colony-forming units from the catheter tip) and incident CRBSIs (meeting the definitions of the Centers for Disease Control and Prevention). Infection-free time (days from initial CVC insertion to initial blood culture positivity) and ICU mortality rates were measured as secondary endpoints.
FINDINGS:
The SC group (N = 135) and CC group (N = 137) were similar in terms of clinical and laboratory parameters at baseline, reasons for ICU admission, complications during CVC insertion, and total time with CVC (mean ± standard deviation; SC 13 ± 24 vs CC 15 ± 37 days). No significant intergroup differences were found in CVC colonization rates (SC 32.6% vs CC 30%; P = 0.7), CRBSI incidence rates (3.36 infections per 1000 catheter-days in both groups), infection-free times (SC 13 ± 34 vs CC 12 ± 12 days; P = 0.85) or ICU mortality (SC 46% vs CC 43%; P = 0.7).
CONCLUSION:
In critically ill patients, use of AgTive(®) silver-nanoparticle-impregnated CVCs had no significant effect on CVC colonization, CRBSI incidence or ICU mortality. These CVCs cannot be recommended as an adjunctive tool for control of CRBSIs
Cleaning the Label of Cured Meat; Effect of the Replacement of Nitrates/Nitrites on Nutrients Bioaccessibility, Peptides Formation, and Cellular Toxicity of In Vitro Digested Salami
Curing salts composed of mixtures of nitrates and nitrites are preservatives widely used in processed meats. Despite many desirable technological effects, their use in meat products has been linked to methemoglobinemia and the formation of nitrosamines. Therefore, an increasing "anti-nitrite feeling" has grown among meat consumers, who search for clean label products. In this view, the use of natural compounds as alternatives represents a challenge for the meat industry. Processing (including formulation and fermentation) induces chemical or physical changes of food matrix that can modify the bioaccessibility of nutrients and the formation of peptides, impacting on the real nutritional value of food. In this study we investigated the effect of nitrate/nitrite replacement with a combination of polyphenols, ascorbate, and nitrate-reducing microbial starter cultures on the bioaccessibility of fatty acids, the hydrolysis of proteins and the release of bioactive peptides after in vitro digestion. Moreover, digested salami formulations were investigated for their impacts on cell proliferation and genotoxicity in the human intestinal cellular model (HT-29 cell line). The results indicated that a replacement of synthetic nitrates/nitrites with natural additives can represent a promising strategy to develop innovative "clean label" salamis without negatively affecting their nutritional value
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