Optimal vaccination policy to prevent endemicity: a stochastic model.

We examine here the effects of recurrent vaccination and waning immunity on the establishment of an endemic equilibrium in a population. An individual-based model that incorporates memory effects for transmission rate during infection and subsequent immunity is introduced, considering stochasticity at the individual level. By letting the population size going to infinity, we derive a set of equations describing the large scale behavior of the epidemic.

Anti-Netrin-1 decorated nanoparticles combined with chemotherapy for the treatment of triple-negative breast cancer.

Nanoparticle's success as drug delivery systems for cancer treatment has been achieved through passive targeting mechanisms. However, tumor heterogeneity and rapid drug clearance limit the treatment efficacy. Improved outcomes and selective drug release can be achieved by grafting ligands at the surface of nanocarriers that bind molecules overexpressed in the tumor microenvironment (TME).

Molecular mechanisms underlying the structural diversity of rhamnose-rich cell wall polysaccharides in lactococci.

In Gram-positive bacteria, cell wall polysaccharides (CWPS) play critical roles in bacterial cell wall homeostasis and bacterial interactions with their immediate surroundings. In lactococci, CWPS consist of two components: a conserved rhamnan embedded in the peptidoglycan layer and a surface-exposed polysaccharide pellicle (PSP), which are linked together to form a large rhamnose-rich CWPS (Rha-CWPS). PSP, whose structure varies from strain to strain, is a receptor for many bacteriophages infecting lactococci.

Nanoemulsions Embedded in Alginate Beads as Bioadhesive Nanocomposites for Intestinal Delivery of the Anti-Inflammatory Drug Tofacitinib.

Oral administration of nanoparticles (NPs) is a promising strategy to overcome solubility and stability issues of many active compounds. However, this route faces major obstacles related to the hostile gastrointestinal (GI) environment, which impairs the efficacy of orally administered nanomedicines. Here, we propose nanocomposites as a promising approach to increase the retention time of NPs in the intestinal tract by using bio- and mucoadhesive matrixes able to protect the cargo until it reaches the targeted area.

PBP2b Mutations Improve the Growth of Phage-Resistant Lacking Polysaccharide Pellicle.

Lactococcus lactis and Lactococcus cremoris are Gram-positive lactic acid bacteria widely used as starter in milk fermentations. Lactococcal cells are covered with a polysaccharide pellicle (PSP) that was previously shown to act as the receptor for numerous bacteriophages of the class. Thus, mutant strains lacking PSP are phage resistant.

Structural variations and roles of rhamnose-rich cell wall polysaccharides in Gram-positive bacteria.

Rhamnose-rich cell wall polysaccharides (Rha-CWPSs) have emerged as crucial cell wall components of numerous Gram-positive, ovoid-shaped bacteria-including streptococci, enterococci, and lactococci-of which many are of clinical or biotechnological importance. Rha-CWPS are composed of a conserved polyrhamnose backbone with side-chain substituents of variable size and structure. Because these substituents contain phosphate groups, Rha-CWPS can also be classified as polyanionic glycopolymers, similar to wall teichoic acids, of which they appear to be functional homologs.

Targeted verbal cues can immediately alter gait following stroke.

Background: Physical therapists use verbal cueing extensively during gait rehabilitation. Nevertheless, little is known about the ability of individuals post-stroke to make immediate changes to targeted spatiotemporal gait parameters from verbal commands. Additionally, adequate muscle strength may be necessary to promote positive alterations in gait.

A Novel Enterococcus faecalis Heme Transport Regulator (FhtR) Senses Host Heme To Control Its Intracellular Homeostasis.

is a commensal Gram-positive pathogen found in the intestines of mammals and is also a leading cause of severe infections occurring mainly among antibiotic-treated dysbiotic hospitalized patients. Like most intestinal bacteria, does not synthesize heme (in this report, heme refers to iron protoporphyrin IX regardless of the iron redox state). Nevertheless, environmental heme can improve fitness by activating respiration metabolism and a catalase that limits hydrogen peroxide stress.

Extended gate field-effect-transistor for sensing cortisol stress hormone.

Cortisol is a hormone released in response to stress and is a major glucocorticoid produced by adrenal glands. Here, we report a wearable sensory electronic chip using label-free detection, based on a platinum/graphene aptamer extended gate field effect transistor (EG-FET) for the recognition of cortisol in biological buffers within the Debye screening length. The device shows promising experimental features for real-time monitoring of the circadian rhythm of cortisol in human sweat.

Sweat Biomarker Sensor Incorporating Picowatt, Three-Dimensional Extended Metal Gate Ion Sensitive Field Effect Transistors.

Ion sensitive field effect transistors (ISFETs) form a very attractive solution for wearable sensors due to their capacity for ultra-miniaturization, low power operation, and very high sensitivity, supported by complementary metal oxide semiconductor (CMOS) integration. This paper reports for the first time, a multianalyte sensing platform that incorporates high performance, high yield, high robustness, three-dimensional-extended-metal-gate ISFETs (3D-EMG-ISFETs) realized by the postprocessing of a conventional 0.18 μm CMOS technology node.

Three-Dimensional Integrated Ultra-Low-Volume Passive Microfluidics with Ion-Sensitive Field-Effect Transistors for Multiparameter Wearable Sweat Analyzers.

Wearable systems could offer noninvasive and real-time solutions for monitoring of biomarkers in human sweat as an alternative to blood testing. Recent studies have demonstrated that the concentration of certain biomarkers in sweat can be directly correlated to their concentrations in blood, making sweat a trusted biofluid candidate for noninvasive diagnostics. We introduce a fully on-chip integrated wearable sweat sensing system to track biochemical information at the surface of the skin in real time.

Theoretical and uniaxial experimental evaluation of human annulus fibrosus degeneration.

The highly organized structure and composition of the annulus fibrosus provides the tissue with mechanical behaviors that include anisotropy and nonlinearity. Mathematical models are necessary to interpret and elucidate the meaning of directly measured mechanical properties and to understand the structure-function relationships of the tissue components, namely, the fibers and extrafibrillar matrix. This study models the annulus fibrosus as a combination of strain energy functions describing the fibers, matrix, and their interactions.

Effect of nucleus replacement device properties on lumbar spine mechanics.

Study Design: A validated nonlinear three-dimensional finite element model of a single lumbar motion segment (L3-L4) was used to evaluate a range of moduli for ideally conforming nucleus replacement devices.

Objective: The objective of the current study was to determine the biomechanical effects of nucleus replacement technology for a variety of implant moduli. We hypothesized that there would be an optimal modulus for a nucleus replacement that would provide loading in the surrounding bone and anulus similar to the intact state.

Quality of motion considerations in numerical analysis of motion restoring implants of the spine.

Background: Motion restoring implants function in a dynamic environment that encompasses the full range of spinal kinematics. Accurate assessment of the in situ performance of these devices using numerical techniques requires model verification and validation against the well-established nonlinear quality of motion of the spine, as opposed to the previous norm of matching kinematic endpoint metrics such as range of motion and intervertebral disc pressure measurements at a single kinematic reference point.

Methods: Experimental data was obtained during cadaveric testing of nine three-functional spinal unit (L3-S1) lumbar spine segments.

N-terminal pro-B-type natriuretic peptide: a measure of significant patent ductus arteriosus.

Background: B-type natriuretic peptide (BNP) is a marker for ventricular dysfunction secreted as a pre-prohormone, pro-B-type natriuretic peptide (proBNP), and cleaved into BNP and a biologically inactive fragment, N-terminal pro-B-type natriuretic peptide (NT-proBNP). Little is known about the clinical usefulness of NT-proBNP in preterm infants.

Objective: To evaluate the usefulness of plasma NT-proBNP in diagnosing haemodynamically significant patent ductus arteriosus (hsPDA) in neonates and examine some factors that might affect this.

Quantifying the contributions of structure to annulus fibrosus mechanical function using a nonlinear, anisotropic, hyperelastic model.

The annulus fibrosus of the intervertebral disc is comprised of concentric lamella of oriented collagen fibers embedded in a hydrated proteoglycan matrix with smaller amounts of minor collagens, elastin, and small proteoglycans. Its structure and composition enable the disc to withstand complex loads and result in inhomogeneous, anisotropic, and nonlinear mechanical behaviors. The specific contributions of the annulus fibrosus constituent structures to mechanical function remain unclear.

The role of fiber-matrix interactions in a nonlinear fiber-reinforced strain energy model of tendon.

The objective of this study was to develop a nonlinear and anisotropic three-dimensional mathematical model of tendon behavior in which the structural components of fibers, matrix, and fiber-matrix interactions are explicitly incorporated and to use this model to infer the contributions of these structures to tendon mechanical behavior. We hypothesized that this model would show that: (i) tendon mechanical behavior is not solely governed by the isotropic matrix and fiber stretch, but is also influenced by fiber-matrix interactions; and (ii) shear fiber-matrix interaction terms will better describe tendon mechanical behavior than bulk fiber-matrix interaction terms. Model versions that did and did not include fiber-matrix interaction terms were applied to experimental tendon stress-strain data in longitudinal and transverse orientations, and the R2 goodness-of-fit was evaluated.

Degeneration affects the fiber reorientation of human annulus fibrosus under tensile load.

The angled, lamellar structure of the annulus fibrosus is integral to its load-bearing function. Reorientation of this fiber structure with applied load may contribute to nonlinear mechanical behavior and to large increases in tensile modulus. Fiber reorientation has not yet been quantified for loaded non-degenerated and degenerated annulus fibrosus tissue.

Self-selection of dietary protein and energy by broilers grown under a tropical climate: effect of feed particle size on the feed choice.

Broilers, 2 wk of age, that had been previously adapted to energy: protein choice feeding, were offered corn (either ground, cracked, or presented as whole grains) and a protein concentrate (43.7% CP) in mash or pellet form. When corn was fed as whole grains, protein concentrate in the selected diet was significantly higher (35.

[Chemical composition of feces from bovines, sheep and goats feeding from Sahelo-Sudanese natural or farming fields: its use for estimating the nutritive value of their diet].

The chemical composition of grazing cattle, sheep and goat feces is described according to animal species, type of range (natural pasture or fields after crops) and season in a sub-Sahelian environment. Nutritive value (organic matter digestibility and digestible crude protein) of forages can be estimated from some chemical fecal criteria.