1,083 research outputs found
Privacy-Aware Processing of Biometric Templates by Means of Secure Two-Party Computation
The use of biometric data for person identification and access control is gaining more and more popularity. Handling biometric data, however, requires particular care, since biometric data is indissolubly tied to the identity of the owner hence raising important security and privacy issues. This chapter focuses on the latter, presenting an innovative approach that, by relying on tools borrowed from Secure Two Party Computation (STPC) theory, permits to process the biometric data in encrypted form, thus eliminating any risk that private biometric information is leaked during an identification process. The basic concepts behind STPC are reviewed together with the basic cryptographic primitives needed to achieve privacy-aware processing of biometric data in a STPC context. The two main approaches proposed so far, namely homomorphic encryption and garbled circuits, are discussed and the way such techniques can be used to develop a full biometric matching protocol described. Some general guidelines to be used in the design of a privacy-aware biometric system are given, so as to allow the reader to choose the most appropriate tools depending on the application at hand
Positive and negative regulation of angiogenesis by soluble vascular endothelial growth factor receptor-1
Vascular endothelial growth factor receptor (VEGFR)-1 exists in different forms, derived from alternative splicing of the same gene. In addition to the transmembrane form, endothelial cells produce a soluble VEGFR-1 (sVEGFR-1) isoform, whereas non-endothelial cells produce both sVEGFR-1 and a different soluble molecule, known as soluble fms-like tyrosine kinase (sFlt)1-14. By binding members of the vascular endothelial growth factor (VEGF) family, the soluble forms reduce the amounts of VEGFs available for the interaction with their transmembrane receptors, thereby negatively regulating VEGFR-mediated signaling. In agreement with this activity, high levels of circulating sVEGFR-1 or sFlt1-14 are associated with different pathological conditions involving vascular dysfunction. Moreover, sVEGFR-1 and sFlt1-14 have an additional role in angiogenesis: they are deposited in the endothelial cell and pericyte extracellular matrix, and interact with cell membrane components. Interaction of sVEGFR-1 with α5β1 integrin on endothelial cell membranes regulates vessel growth, triggering a dynamic, pro-angiogenic phenotype. Interaction of sVEGFR-1/sFlt1-14 with cell membrane glycosphingolipids in lipid rafts controls kidney cell morphology and glomerular barrier functions. These cell-matrix contacts represent attractive novel targets for pharmacological intervention in addition to those addressing interactions between VEGFs and their receptors
The random growth of interfaces as a subordinated process
We study the random growth of surfaces from within the perspective of a
single column, namely, the fluctuation of the column height around the mean
value, y(t)= h(t)-, which is depicted as being subordinated to a
standard fluctuation-dissipation process with friction gamma. We argue that the
main properties of Kardar-Parisi-Zhang theory, in one dimension, are derived by
identifying the distribution of return times to y(0) = 0, which is a truncated
inverse power law, with the distribution of subordination times. The agreement
of the theoretical prediction with the numerical treatment of the 1 + 1
dimensional model of ballistic deposition is remarkably good, in spite of the
finite size effects affecting this model.Comment: LaTeX, 4 pages, 3 figure
The finite element method for fractional non-local thermal energy transfer in non-homogeneous rigid conductors
In a non-local fractional-order model of thermal energy transport recently introduced by the authors, it is assumed that local and non-local contributions coexist at a given observation scale: while the first is described by the classical Fourier transport law, the second involves couples of adjacent and non-adjacent elementary volumes, and is taken as proportional to the product of the masses of the interacting volumes and their relative temperature, through a material-dependent, distance-decaying power-law function. As a result, a fractional-order heat conduction equation is derived. This paper presents a pertinent finite element method for the solution of the proposed fractional-order heat conduction equation. Homogenous and non-homogeneous rigid bodies are considered. Numerical applications are carried out on 1D and 2D bodies, including a standard finite difference solution for validation
Tailoring the excitation of localized surface plasmon-polariton resonances by focusing radially-polarized beams
We study the interaction of focused radially-polarized light with metal
nanospheres. By expanding the electromagnetic field in terms of multipoles, we
gain insight on the excitation of localized surface plasmon-polariton
resonances in the nanoparticle. We show that focused radially-polarized beams
offer more opportunities than a focused plane wave or a Gaussian beam for
tuning the near- and far-field system response. These results find applications
in nano-optics, optical tweezers, and optical data storage.Comment: 4 pages, 3 figure
Campylobacter jejuni bacteremia in the setting of pancytopenia
Introduction: Campylobacter species are a common infectious cause of acute diarrhea worldwide. Small gram-negative bacteria, Campylobacter species are commonly transmitted fecal-orally and frequently found nonpathogenically in the guts of animals including chickens, creating a risk for frequent animal-human transmission. Campylobacter jejuni, one of the most important Campylobacter species for human health, typically produces a watery or inflammatory diarrhea. It is common in developing countries and outbreaks are often linked to contaminated water, unpasteurized milk, undercooked poultry, and contact with animals or infected persons. C. jejuni is a fastidious, gram-negative spiral-shaped rod which is best detected by culture but can also be seen on microscopic examination of a stool sample of a symptomatic patient with enteritis. Microscopy typically also reveals red blood cells or neutrophils. Culture is usually performed using a selective agar with sheep blood, vancomycin, amphotericin B, cephalothin, polymyxin B, and trimethoprim, incubated at 42 degrees with 5-10% oxygen, 1-10% carbon dioxide, and some hydrogen. C. jejuni typically presents in adults with diarrhea, commonly associated with abdominal pain and a high fever. The diarrhea is usually watery but frequently becomes bloody. Symptoms usually peak for 24-48 hours before gradually resolving, but some cases can last up to a week. While antibiotics are not typically necessary, as the course is short, they are commonly used in more severe or prolonged cases or in cases where the patient has immunosuppression or immunodeficiency. Infection can spread to contiguous organs, including the pancreas or gallbladder, and bacteremia can lead to seeding of distant organs, though bacteremia is rare and usually occurs only in immunocompromised patients. Complications of infection can include Guillain-Barre syndrome, reactive arthritis, and spontaneous abortion.
Case description: Our patient is a 57-year-old woman with a past medical history of decompensated NASH cirrhosis and type II diabetes mellitus currently undergoing workup for a pancytopenia who presented to our emergency department with low-grade fever two days after bone marrow biopsy. She was found to have a two-day history of explosive watery yellow stool without any nausea, vomiting, or abdominal discomfort. Her temperature was 38.1 degrees Celsius with an increase in white blood cells to 4,000 from her baseline of 3,000, with minor increases in creatinine and liver enzymes stable as per her baseline. On CT, she had mild duodenitis. Influenza and Clostridium difficile workup were negative. Stool and blood cultures were taken and she was started on IV vancomycin and cefepime for her neutropenic fever. Stool culture came back positive for C. jejuni and blood cultures later came back positive for the same, demonstrating curved gram-negative bacteria. Due to her neutropenia and her existing once-weekly ciprofloxacin dosing for spontaneous bacterial peritonitis prophylaxis, she was treated azithromycin for a total of 7 days. During her inpatient stay, her bone marrow biopsy also came back and appeared normal. She was discharged to follow up on the pancytopenia with her usual doctors, continuing her SBP prophylaxis and counseled on common complications of C. jejuni.
Discussion: Bacteremia is an uncommon consequence of C. jejuni enteritis, though it is also likely underreported due to difficulty in culturing and lack of indication in many patients. Risk of bacteremia increases with immunocompromise, but patients who are not immunocompromised may also be affected. C. jejuni can evade host defenses with several virulence factors, including flagella, cytotoxin, and serum resistance. Risk is also increased with old age and male gender, as well. While most cases may go unnoticed due to the short, self-limiting course of the diarrheal illness, an increased suspicion in patients with immunocompromise may be warranted.https://scholarlycommons.henryford.com/merf2020caserpt/1128/thumbnail.jp
Influence of bunch exposure on anthocyanins extractability from grapes skins (Vitis vinifera L.)
In relation to bunch exposure to solar irradiance (sun exposed vs. leaf shaded conditions), anthocyanin ripening and extractability were studied in two grape cultivars ('Croatina' and 'Pinot Noir') coming from three different vineyards in Northern Italy. Analysis of anthocyanin content were carried out by HPLC and spectrophotometry, and a simulated maceration process was developed. Pigments extraction occurred mainly in the first few hours of the maceration process. Anthocyanins with disubstituted B-ring showed a faster extractability than the trisubsituted ones. Bunch exposure to sunlight seemed to be important for pigment extractability timing in winemaking, showing a delay in pigments release. This delay was only partially explained by the different pigments profile, with higher percentage of disubstituted compounds in shaded berries, because all the molecules indicated a similar extraction trend during maceration.
On the vibrations of a mechanically based non-local beam model
The vibration problem of a Timoshenko non-local beam is addressed. The beam model involves assuming that the equilibrium of each volume element is attained due to contact forces and long-range body forces exerted, respectively, by adjacent and non-adjacent volume elements. The contact forces result in the classical Cauchy stress tensor while the long-range forces are taken as depending on the product of the interacting volume elements and on their relative displacement through a material-dependent distance-decaying function. To derive the motion equations and the related mechanical boundary conditions, the Hamilton's principle is appliedThe vibration problem of a Timoshenko non-local beam is addressed. The beam model involves assuming that the equilibrium of each volume element is attained due to contact forces and long-range body forces exerted, respectively, by adjacent and non-adjacent volume elements. The contact forces result in the classical Cauchy stress tensor while the long-range forces are taken as depending on the product of the interacting volume elements and on their relative displacement through a material-dependent distance-decaying function. To derive the motion equations and the related mechanical boundary conditions, the Hamilton's principle is applie
Potassium partitioning between leaves and clusters: Role of rootstock
Different scion/rootstock combinations in grapevine (Vitis vinifera/Vitis spp.) were tested for nutritional properties and juice composition. Chardonnay and Cabernet Sauvignon each grafted on 22 rootstock varieties (10 new crosses and 12 already used in viticulture) were grown in outdoor pots containing very poor nutritional substrate. Crop load had a strong effect on juice composition and potassium nutrition. Results indicate that under our experimental conditions rootstock can have an effect on potassium partitioning between leaves and cluster 9 out of 22 rootstocks that we tried were able to improve leaf potassium content without inducing a significant increase in juice potassium conten
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