New highly luminescent hybrid materials: terbium pyridine-picolinate covalently grafted on kaolinite

Luminescent hybrid materials derived from kaolinite appear as promising materials for optical applications due to their specific properties. The spectroscopic behavior of terbium picolinate complexes covalently grafted on kaolinite and the influence of the secondary ligand and thermal treatment on luminescence are reported. The resulting materials were characterized by thermal analysis, element analysis, X-ray diffraction, infrared absorption spectroscopy, and photoluminescence. The thermogravimetric curves indicated an enhancement in the thermal stability up to 300 °C for the lanthanide complexes covalently grafted on kaolinite, with respect to the isolated complexes. The increase in the basal spacing observed by X-ray diffraction confirmed the insertion of the organic ligands into the basal space of kaolinite, involving the formation of a bond between Al-OH and the carboxylate groups, as evidenced by infrared spectroscopy. The luminescent hybrid material exhibited a stronger characteristic emission of Tb(3+) compared to the isolated complex. The excitation spectra displayed a broad band at 277 nm, assigned to a ligand-to-metal charge transfer, while the emission spectra presented bands related to the electronic transitions characteristic of the Tb(3+) ion from the excited state (5)D(4) to the states (7)F(J) (J=5, 4, and 3), with the 4→5 transition having high intensity with green emission.     

Minimal within-host dengue models highlight the specific roles of the immune response in primary and secondary dengue infections

In recent years, the within-host viral dynamics of dengue infections have been increasingly characterized, and the relationship between aspects of these dynamics and the manifestation of severe disease has been increasingly probed. Despite this progress, there are few mathematical models of within-host dengue dynamics, and the ones that exist focus primarily on the general role of immune cells in the clearance of infected cells, while neglecting other components of the immune response in limiting viraemia. Here, by considering a suite of mathematical within-host dengue models of increasing complexity, we aim to isolate the critical components of the innate and the adaptive immune response that suffice in the reproduction of several well-characterized features of primary and secondary dengue infections. By building up from a simple target cell limited model, we show that only the innate immune response is needed to recover the characteristic features of a primary symptomatic dengue infection, while a higher rate of viral infectivity (indicative of antibody-dependent enhancement) and infected cell clearance by T cells are further needed to recover the characteristic features of a secondary dengue infection. We show that these minimal models can reproduce the increased risk of disease associated with secondary heterologous infections that arises as a result of a cytokine storm, and, further, that they are consistent with virological indicators that predict the onset of severe disease, such as the magnitude of peak viraemia, time to peak viral load, and viral clearance rate. Finally, we show that the effectiveness of these virological indicators to predict the onset of severe disease depends on the contribution of T cells in fuelling the cytokine storm.     

Chemical modification and structural rearrangements of polyketone‐based polymer membrane

Alternating polyketones constitute a very interesting class of polymers, which can be modified for the preparation of functional polymers. The chemical modification of polyketone using 1,2‐diaminopropane was used to prepare a conductive membrane. This paper is focused on the synthesis and structural rearrangements of polyamine for preparing anion‐exchange membranes by the solvent casting technique. According to the Paal‐Knorr mechanism, 1,4‐dicarbonyl of polyketone reacts with 1,2‐diaminopropane to form a pyrrole ring along the polyketone backbone. In addition, the so‐modified polyamines can undergo structural rearrangements to form N‐substituted pyrrole crosslinked with dihydropyridine units. The conversion degree and the N content are quite low. The pathway reactions have been proposed on the basis of ¹H‐NMR, ultraviolet–visible, and Fourier transform infrared results. Scanning electron microscopy, differential scanning calorimetry, and X‐ray diffraction techniques were used to study the morphological, thermal, and structural characteristics of the modified polyketone, as well as the correspondoing membrane. The experimental results indicated that the membrane is a potential candidate for energy conversion technology. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45485.     

Comprehensive Profiling of Secretome Formulations from Fetal- and Perinatal Human Amniotic Fluid Stem Cells

We previously reported that c-KIT+ human amniotic-fluid derived stem cells obtained from leftover samples of routine II trimester prenatal diagnosis (fetal hAFS) are endowed with regenerative paracrine potential driving pro-survival, anti-fibrotic and proliferative effects. hAFS may also be isolated from III trimester clinical waste samples during scheduled C-sections (perinatal hAFS), thus offering a more easily accessible alternative when compared to fetal hAFS. Nonetheless, little is known about the paracrine profile of perinatal hAFS. Here we provide a detailed characterization of the hAFS total secretome (i.e., the entirety of soluble paracrine factors released by cells in the conditioned medium, hAFS-CM) and the extracellular vesicles (hAFS-EVs) within it, from II trimester fetal- versus III trimester perinatal cells. Fetal- and perinatal hAFS were characterized and subject to hypoxic preconditioning to enhance their paracrine potential. hAFS-CM and hAFS-EV formulations were analyzed for protein and chemokine/cytokine content, and the EV cargo was further investigated by RNA sequencing. The phenotype of fetal- and perinatal hAFS, along with their corresponding secretome formulations, overlapped; yet, fetal hAFS showed immature oxidative phosphorylation activity when compared to perinatal ones. The profiling of their paracrine cargo revealed some differences according to gestational stage and hypoxic preconditioning. Both cell sources provided formulations enriched with neurotrophic, immunomodulatory, anti-fibrotic and endothelial stimulating factors, and the immature fetal hAFS secretome was defined by a more pronounced pro-vasculogenic, regenerative, pro-resolving and anti-aging profile. Small RNA profiling showed microRNA enrichment in both fetal- and perinatal hAFS-EV cargo, with a stably- expressed pro-resolving core as a reference molecular signature. Here we confirm that hAFS represents an appealing source of regenerative paracrine factors; the selection of either fetal or perinatal hAFS secretome formulations for future paracrine therapy should be evaluated considering the specific clinical scenario.     

Extension of the Terpene Chemical Space: the Very First Biosynthetic Steps

The structural diversity of terpenes is particularly notable and many studies are carried out to increase it further. In the terpene biosynthetic pathway this diversity is accessible from only two common precursors, i. e. isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Methods recently developed (e. g. the Terpene Mini Path) have allowed DMAPP and IPP to be obtained from a two-step enzymatic conversion of industrially available isopentenol (IOH) and dimethylallyl alcohol (DMAOH) into their corresponding diphosphates. Easily available IOH and DMAOH analogues then offer quick access to modified terpenoids thus avoiding the tedious chemical synthesis of unnatural diphosphates. The aim of this minireview is to cover the literature devoted to the use of these analogues for widening the accessible terpene chemical space.     

Assessment of TSPAN Expression Profile and Their Role in the VSCC Prognosis

The role and prognostic value of tetraspanins (TSPANs) in vulvar squamous cell carcinoma (VSCC) remain poorly understood. We sought to primarily determine, at both the molecular and tissue level, the expression profile of the TSPANs CD9, CD63, CD81, and CD82 in archived VSCC samples (n = 117) and further investigate their clinical relevance as prognostic markers. Our studies led us to identify CD63 as the most highly expressed TSPAN, at the gene and protein levels. Multicomparison studies also revealed that the expression of CD9 was associated with tumor size, whereas CD63 upregulation was associated with histological diagnosis and vascular invasion. Moreover, low expression of CD81 and CD82 was associated with worse prognosis. To determine the role of TSPANs in VSCC at the cellular level, we assessed the mRNA levels of CD63 and CD82 in established metastatic (SW962) and non-metastatic (SW954) VSCC human cell lines. CD82 was found to be downregulated in SW962 cells, thus supporting its metastasis suppressor role. However, CD63 was significantly upregulated in both cell lines. Silencing of CD63 by siRNA led to a significant decrease in proliferation of both SW954 and SW962. Furthermore, in SW962 particularly, CD63-siRNA also remarkably inhibited cell migration. Altogether, our data suggest that the differential expression of TSPANs represents an important feature for prognosis of VSCC patients and indicates that CD63 and CD82 are likely potential therapeutic targets in VSCC.