Polyimides (PIs) represent a benchmark for high-performance polymers on the basis of a remarkable collection of valuable traits and accessible production pathways and therefore have incited serious ...attention from the ever-demanding medical field. Their characteristics make them suitable for service in hostile environments and purification or sterilization by robust methods, as requested by most biomedical applications. Even if PIs are generally regarded as “biocompatible”, proper analysis and understanding of their biocompatibility and safe use in biological systems deeply needed. This mini-review is designed to encompass some of the most robust available research on the biocompatibility of various commercial or noncommercial PIs and to comprehend their potential in the biomedical area. Therefore, it considers (i) the newest concepts in the field, (ii) the chemical, (iii) physical, or (iv) manufacturing elements of PIs that could affect the subsequent biocompatibility, and, last but not least, (v) in vitro and in vivo biocompatibility assessment and (vi) reachable clinical trials involving defined polyimide structures. The main conclusion is that various PIs have the capacity to accommodate in vivo conditions in which they are able to function for a long time and can be judiciously certified as biocompatible.
Two neutral copper(I) halide complexes (Cu(BTU)
X,
= Cl, Br) were prepared by the reduction of the corresponding copper(II) halides (chloride or bromide) with a benzoylthiourea (BTU,
...-(3,4-diheptyloxybenzoyl)-
'-(4-heptadecafluorooctylphenyl)thiourea) ligand in ethanol. The two copper(I) complexes show a very interesting combination of 2D supramolecular structures, liquid crystalline, emission, and 1D ionic conduction properties. Their chemical structure was ascribed based on ESI-MS, elemental analysis, IR, and NMR spectroscopies (
H and
C), while the mesomorphic behavior was analyzed through a combination of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (XRD). These new copper(I) complexes have mesomorphic properties and exhibit a hexagonal columnar mesophase over a large temperature range, more than 100 K, as evidenced by DSC studies and POM observations. The thermogravimetric analysis (TG) indicated a very good thermal stability of these samples up to the isotropization temperatures and over the whole temperature range of the liquid crystalline phase existence. Both complexes displayed a solid-state emission with quantum yields up to 8% at ambient temperature. The electrical properties of the new metallomesogens were investigated by variable temperature dielectric spectroscopy over the entire temperature range of the liquid crystalline phase. It was found that the liquid crystal phases favoured anhydrous proton conduction provided by the hydrogen-bonding networks formed by the NH…X moieties (
= halide or oxygen) of the benzoylthiourea ligand in the copper(I) complexes. A proton conductivity of 2.97 × 10
S·cm
was achieved at 430 K for the chloro-complex and 1.37 × 10
S·cm
at 440K for the related bromo-complex.
We discuss the existence of a strengthening of Hermite–Hadamard inequality in the case of log-convex functions. Unlike the classical case, which belongs to the field of linear functional analysis, ...this analogue involves nonlinear means such as the geometric mean and the logarithmic mean.
An RNA aptamer selected for binding to the fluorogenic cyanine dye, dimethylindole red (DIR), also binds and activates another cyanine, oxazole thiazole blue (OTB), giving two well-resolved emission ...colors. The aptamer binds to each dye with submicromolar K D values, and the resulting fluoromodules exhibit fluorescence quantum yields ranging from 0.17 to 0.51 and excellent photostability. The aptamer was fused to a second aptamer previously selected for binding to the epidermal growth factor receptor (EGFR) to create a bifunctional aptamer that labels cell-surface EGFR on mammalian cells. The fluorescent color of the aptamer-labeled EGFR can be switched between blue and red in situ simply by exchanging the dye in the medium. The promiscuity of the aptamer can also be used to distinguish between cell-surface and internalized EGFR on the basis of the addition of red or blue fluorogen at different times.
The property of isotonicity of a continuous convex function on the positive cone is characterized via subdifferentials. This is used to illustrate a new generalization of the Hardy–Littlewood–Pólya ...inequality of majorization to the case of functions of a vector variable.
In laying hens, a diet supplemented with tryptophan (Trp) has been shown to affect their pecking behavior. However, unlike this positive effect, Trp is also involved in negative effects on behavior ...and stress through indolic pathways. Indole production can be reduced by probiotics (Pro), thus we hypothesized that Pro may prevent negative effects of Trp and increase beneficial effects on behavior in birds. Combined effects of Pro and Trp were also expected. To investigate the effects on behavior in birds of supplementing with a high level of Trp with or without Pro, Japanese quail were used because their behavior can be influenced by Pediococcus acidilactici, and they can be highly aggressive. Quails (n = 120) were assigned to 4 groups in a 2 × 2 factorial design for 55 d: C-C (control diet with usual Trp level, 0.3%; without Pro; n = 30), Trp-C (Trp: 2%; without Pro; n = 30), C-Pro (control diet; with Pro: 1 x 109 CFU/L P. acidilactici in drinking water; n = 30), and Trp-Pro (Trp 2%; with Pro; n = 30). Body weight was measured every week, and different tests were conducted to investigate behavioral characteristics of each quail. Contrary to our hypothesis, there was almost no interaction between Trp and Pro treatments. Tryptophan supplementation significantly (P < 0.05) reduced live weight up to 27 d, whereas Pro treatment had no effect. There was no significant difference between groups for tonic immobility variables (P > 0.05). The birds fed the high Trp diet spent significantly less time in the periphery of the open field than those fed the control diet and moved less in the arena during the social isolation test. Interindividual distances were significantly lower in males fed with Trp 2% than with the control diet, whereas Trp and Pro supplements interacted in females. The treatments did not affect sexual motivation in males. These results indicate that a high level of Trp reduced growth and appeared to enhance emotional reactivity in quails and that supplementing with Pro did not reduce these effects. In conclusion, feeding high Trp for 55 d cannot be recommended as a strategy to improve social behavior unlike effects observed in laying hens.
We prove global existence for a nonlinear Smoluchowski equation (a nonlinear Fokker-Planck equation) coupled with Navier-Stokes equations in 2d. The proof uses a deteriorating regularity estimate in ...the spirit of 5 (see also 1).
The DIR2s RNA aptamer, a second-generation, in-vitro selected binder to dimethylindole red (DIR), activates the fluorescence of cyanine dyes, DIR and oxazole thiazole blue (OTB), allowing detection ...of two well-resolved emission colors. Using Fab BL3-6 and its cognate hairpin as a crystallization module, we solved the crystal structures of both the apo and OTB-SO
bound forms of DIR2s at 2.0 Å and 1.8 Å resolution, respectively. DIR2s adopts a compact, tuning fork-like architecture comprised of a helix and two short stem-loops oriented in parallel to create the ligand binding site through tertiary interactions. The OTB-SO
fluorophore binds in a planar conformation to a claw-like structure formed by a purine base-triple, which provides a stacking platform for OTB-SO
and an unpaired nucleotide, which partially caps the binding site from the top. The absence of a G-quartet or base tetrad makes the DIR2s aptamer unique among fluorogenic RNAs with known 3D structure.
A note on the Choquet type operators Gal, Sorin G.; Niculescu, Constantin P.
Aequationes mathematicae,
06/2021, Letnik:
95, Številka:
3
Journal Article
Recenzirano
Odprti dostop
In this note Choquet type operators are introduced in connection with Choquet’s theory of integrability with respect to a not necessarily additive set function. Based on their properties, a ...quantitative estimate for the nonlinear Korovkin type approximation theorem associated to Bernstein–Kantorovich–Choquet operators is proved. The paper also includes a large generalization of Hölder’s inequality within the framework of monotone and sublinear operators acting on spaces of continuous functions.
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