Genotyping of European Toxoplasma gondii strains by a new high-resolution next-generation sequencing-based method.

PURPOSE: A new high-resolution next-generation sequencing (NGS)-based method was established to type closely related European type II Toxoplasma gondii strains. METHODS: T. gondii field isolates were collected from different parts of Europe and assessed by whole genome sequencing (WGS). In comparison to ME49 (a type II reference strain), highly polymorphic regions (HPRs) were identified, showing a considerable number of single nucleotide polymorphisms (SNPs). After confirmation by Sanger sequencing, 18 HPRs were used to design a primer panel for multiplex PCR to establish a multilocus Ion AmpliSeq typing method. Toxoplasma gondii isolates and T. gondii present in clinical samples were typed with the new method. The sensitivity of the method was tested with serially diluted reference DNA samples. RESULTS: Among type II specimens, the method could differentiate the same number of haplotypes as the reference standard, microsatellite (MS) typing. Passages of the same isolates and specimens originating from abortion outbreaks were identified as identical. In addition, seven different genotypes, two atypical and two recombinant specimens were clearly distinguished from each other by the method. Furthermore, almost all SNPs detected by the Ion AmpliSeq method corresponded to those expected based on WGS. By testing serially diluted DNA samples, the method exhibited a similar analytical sensitivity as MS typing. CONCLUSION: The new method can distinguish different T. gondii genotypes and detect intra-genotype variability among European type II T. gondii strains. Furthermore, with WGS data additional target regions can be added to the method to potentially increase typing resolution.

Acquired SERPINC1/antithrombin deficiency during oral contraceptive consumption: a case report.

BACKGROUND: SERPINC1 is a glycoprotein that regulates blood coagulation. SERPINC1 congenital or acquired deficiencies represent a significant risk factor for thromboembolic disease. SERPINC1 acquired defects are observed in very few cases and can occur in many clinical conditions such as treatment with L-asparaginase or oral contraceptive (particularly estrogen derivatives), but these conditions are not routinely investigated. CASE PRESENTATION: A 50-year-old Caucasian woman who took gestodene 75 µg/ethinylestradiol 20 µg as oral contraceptive, was sent to our thrombophilia clinic because, on thrombophilia testing, a reduction of SERPINC1 (74%) and a slight increase in circulating D-dimer and homocysteine were found. We investigated triggers of such SERPINC1 reduction, and identified gestodene 75 µg/ethinylestradiol 20 µg use as the most likely candidate. Two months after the discontinuation of the oral contraceptive, SERPINC1 value returned to normal (92%) and D-dimer and homocysteine were normalized. CONCLUSION: Each patient has a different sensitivity to contraceptive use. Genetic (or epigenetic) regulation of anticoagulant proteins might account for a different rate of consumption of anticoagulant proteins as oral contraceptives and probably determine the susceptibility to thrombotic events.

Vibronic exciton model for low bandgap donor-acceptor polymers.

A vibronic exciton model is introduced to describe the excited state band structure and associated absorption spectra of low bandgap donor-acceptor conjugated polymers. The Hamiltonian is represented in a diabatic basis consisting of Frenkel-like donor and acceptor fragment excitations as well as charge-transfer (CT) excitations between neighboring fragments. States are coupled to each other through electron and hole transfer as well as Coulombically, through interacting fragment transition dipole moments. Local vibronic coupling involving the prominent aromatic-quinoidal vibrational mode, which is responsible for pronounced vibronic progressions in most conjugated oligomers and polymers, is also included. The DAD repeat unit is shown to behave like a J-aggregate trimer, driven by both the sizable in-phase electron and hole transfer integrals between donor and acceptor fragments as well as negative Coulomb coupling between donor and acceptor fragment excitations. The J-aggregate behavior is enhanced in the polymer limit through inter-repeat unit coupling, with the 0-0 vibronic peak significantly enhanced in the lowest-energy near-IR band. In addition, the radiative rate is enhanced by the number of coherently connected repeat units. The near-IR band is shown to possess roughly equal admixtures of CT and Frenkel-like excitations. Applications are made to the polymer PffBT4T-2DT, with the simulated absorption spectrum quantitatively capturing the salient features of the measured spectrum.

Self-assembly of glycerol monooleate with the antimicrobial peptide LL-37: a molecular dynamics study.

Over the past decade, the rapid increase in the incidence of antibiotic-resistant bacteria has promoted research towards alternative therapeutics such as antimicrobial peptides (AMPs), but their biodegradability limits their application. Encapsulation into nanocarriers based on the self-assembly of surfactant-like lipids is emerging as a promising strategy for the improvement of AMPs' stability and their protection against degradation when in biological media. An in-depth understanding of the interactions between the structure-forming lipids and AMPs is required for the design of nanocarriers. This in silico study, demonstrates the self-assembly of the amphiphilic lipid glycerol monooleate (GMO) with the antimicrobial peptide LL-37 into nanocarriers on the molecular scale. Molecular dynamics (MD) simulations show the formation of direct micelles, with either one or two interacting LL-37, and vesicles in this two-component system in agreement with experimental results from small-angle X-ray scattering studies. The hydrophobic contacts between LL-37 and GMOs in water appear responsible for the formation of these nanoparticles. The results also suggest that the enhanced antimicrobial efficiency of LL-37 in these nanocarriers that was previously observed experimentally can be explained by the availability of its side chains with charged amino acids, an increase of the electrostatic interaction and a decrease of the peptide's conformational entropy upon interacting with GMO. The results of this study contribute to the fundamental understanding of lipid-AMP interactions and may guide the comprehensive design of lipid-based self-assembled nanocarriers for antimicrobial peptides.

The relationship between the presence of antibodies and direct detection of Toxoplasma gondii in slaughtered calves and cattle in four European countries.

In cattle, antibodies to Toxoplasma gondii infection are frequently detected, but evidence for the presence of T. gondii tissue cysts in cattle is limited. To study the concordance between the presence of anti-T. gondii IgG and viable tissue cysts of T. gondii in cattle, serum, liver and diaphragm samples of 167 veal calves and 235 adult cattle were collected in Italy, the Netherlands, Romania and the United Kingdom. Serum samples were tested for anti-T. gondii IgG by the modified agglutination test and p30 immunoblot. Samples from liver were analyzed by mouse bioassay and PCR after trypsin digestion. In addition, all diaphragms of cattle that had tested T. gondii-positive (either in bioassay, by PCR on trypsin-digested liver or serologically by MAT) and a selection of diaphragms from cattle that had tested negative were analyzed by magnetic capture quantitative PCR (MC-PCR). Overall, 13 animals were considered positive by a direct detection method: seven out of 151 (4.6%) by MC-PCR and six out of 385 (1.6%) by bioassay, indicating the presence of viable parasites. As cattle that tested positive in the bioassay tested negative by MC-PCR and vice-versa, these results demonstrate a lack of concordance between the presence of viable parasites in liver and the detection of T. gondii DNA in diaphragm. In addition, the probability to detect T. gondii parasites or DNA in seropositive and seronegative cattle was comparable, demonstrating that serological testing by MAT or p30 immunoblot does not provide information about the presence of T. gondii parasites or DNA in cattle and therefore is not a reliable indicator of the risk for consumers.

Robust singlet fission in pentacene thin films with tuned charge transfer interactions.

Singlet fission, the spin-allowed photophysical process converting an excited singlet state into two triplet states, has attracted significant attention for device applications. Research so far has focused mainly on the understanding of singlet fission in pure materials, yet blends offer the promise of a controlled tuning of intermolecular interactions, impacting singlet fission efficiencies. Here we report a study of singlet fission in mixtures of pentacene with weakly interacting spacer molecules. Comparison of experimentally determined stationary optical properties and theoretical calculations indicates a reduction of charge-transfer interactions between pentacene molecules with increasing spacer molecule fraction. Theory predicts that the reduced interactions slow down singlet fission in these blends, but surprisingly we find that singlet fission occurs on a timescale comparable to that in pure crystalline pentacene. We explain the observed robustness of singlet fission in such mixed films by a mechanism of exciton diffusion to hot spots with closer intermolecular spacings.

Optical glucose sensing using ethanolamine-polyborate complexes.

Wound monitoring is essential to tackle chronic complications at their infancy and thus objectively scrutinize any delay in the epithelization process. Since glucose in wound exudates is recognized as key bio-marker in wound monitoring, the development of a cost-efficient detection method for glucose would aid at tackling early-stage infections in wounds. For the first time, we present a novel platform for one-step synthesis of non-enzymatic, cost-efficient optical glucose sensors. These are based on complexes formed by the interactions between polyborates and ethanolamines. The complexes, synthesized by just heating a solution of boric acid and ethanolamines at 150 °C, were characterized using 13C-NMR, 1H-NMR, 11B-NMR, analytical ultracentrifugation and DFT. The results show that the complexes in solution are extremely small (hydrodynamic diameter of around 0.5 nm) and that the polyborates species interact with the ethanolamines via both moderate and weak hydrogen bondings. These complexes were then tested on glucose concentrations ranging from 0 to 10 mM, showing significant changes in the fluorescent emission between the glucose level expressed in an healable wound (5.0-7.6 mM) and a chronic one (0.3-1.0 mM).

The relationship between skin function, barrier properties, and body-dependent factors.

BACKGROUND: Skin is a multilayer interface between the body and the environment, responsible for many important functions, such as temperature regulation, water transport, sensation, and protection from external triggers. OBJECTIVES: This paper provides an overview of principal factors that influence human skin and describes the diversity of skin characteristics, its causes and possible consequences. It also discusses limitations in the barrier function of the skin, describing mechanisms of absorption. METHODS: There are a number of in vivo investigations focusing on the diversity of human skin characteristics with reference to barrier properties and body-dependent factors. RESULTS: Skin properties vary among individuals of different age, gender, ethnicity, and skin types. In addition, skin characteristics differ depending on the body site and can be influenced by the body-mass index and lifestyle. Although one of the main functions of the skin is to act as a barrier, absorption of some substances remains possible. CONCLUSIONS: Various factors can alter human skin properties, which can be reflected in skin function and the quality of everyday life. Skin properties and function are strongly interlinked.

A compliant and biomimetic three-layered vascular graft for small blood vessels.

Engineering a small diameter vascular graft with mechanical and biological properties comparable to living tissues remains challenging. Often, current devices lead to thrombosis and unsatisfactory long-term patency as a result of poor blood compatibility and a mismatch between the mechanical properties of the living tissue and the implanted biomaterial. Addressing all these requirements is essential to produce scaffolds able to survive throughout the life of the patient. For this purpose, we fabricated a novel three-layered vascular graft by combining electrospinning and braiding. Mirroring the structure of human blood vessels, the proposed device is composed of three layers: the intima, the media, and the adventitia. The intima and media layers were obtained by sequentially electrospinning silk fibroin (SF) and poly(L-lactide-co-ε-caprolactone), with ratios selected to match the mechanical properties of the native tissue. For the outer layer, the adventitia, SF yarns were braided on top of the electrospun tubes to create a structure able to withstand high pressures. Compliance, Young's modulus and deformability of the obtained scaffold were similar to that of human blood vessels. Additionally, cytocompatibility of the two layers, media and intima, was assessed in vitro by analysing cell metabolic activity and proliferation of endothelial cells and smooth muscle cells, respectively. Furthermore, heparin functionalization of the scaffolds led to improved anticoagulant properties upon incubation in whole blood. The obtained results indicate a potential application of the herewith designed three-layered construct as a vascular graft for small diameter blood vessel engineering.

New algorithm for analyzing phosphorescence curves: Its application to the K2YF5:Pr compound.

Analysis of phosphorescence curves is an alternative procedure to glow curve analysis in order to find the parameters characterizing trap and recombination centers of thermoluminescence materials. In this article a new algorithm to analyze phosphorescence curves is reported, which is derived from the set of coupled differential equation describing the carrier traffic without resorting to approximations. The new algorithm has been employed to analyze the phosphorescence curves of the K2YF5:Pr compound.

Fibrous scaffolds fabricated by emulsion electrospinning: from hosting capacity to in vivo biocompatibility.

Electrospinning is a versatile method for preparing functional three-dimensional scaffolds. Synthetic and natural polymers have been used to produce micro- and nanofibers that mimic extracellular matrices. Here, we describe the use of emulsion electrospinning to prepare blended fibers capable of hosting aqueous species and releasing them in solution. The existence of an aqueous and a non-aqueous phase allows water-soluble molecules to be introduced without altering the structure and the degradation of the fibers, and means that their release properties under physiological conditions can be controlled. To demonstrate the loading capability and flexibility of the blend, various species were introduced, from magnetic nanoparticles and quantum rods to biological molecules. Cellular studies showed the spontaneous adhesion and alignment of cells along the fibers. Finally, in vivo experiments demonstrated the high biocompatibility and safety of the scaffolds up to 21 days post-implantation.

Materials used to simulate physical properties of human skin.

BACKGROUND: For many applications in research, material development and testing, physical skin models are preferable to the use of human skin, because more reliable and reproducible results can be obtained. PURPOSE: This article gives an overview of materials applied to model physical properties of human skin to encourage multidisciplinary approaches for more realistic testing and improved understanding of skin-material interactions. METHODS: The literature databases Web of Science, PubMed and Google Scholar were searched using the terms 'skin model', 'skin phantom', 'skin equivalent', 'synthetic skin', 'skin substitute', 'artificial skin', 'skin replica', and 'skin model substrate.' Articles addressing material developments or measurements that include the replication of skin properties or behaviour were analysed. RESULTS: It was found that the most common materials used to simulate skin are liquid suspensions, gelatinous substances, elastomers, epoxy resins, metals and textiles. Nano- and micro-fillers can be incorporated in the skin models to tune their physical properties. CONCLUSION: While numerous physical skin models have been reported, most developments are research field-specific and based on trial-and-error methods. As the complexity of advanced measurement techniques increases, new interdisciplinary approaches are needed in future to achieve refined models which realistically simulate multiple properties of human skin.

Optical microcavities enhance the exciton coherence length and eliminate vibronic coupling in J-aggregates.

The properties of polaritons in J-aggregate microcavities are explored using a Hamiltonian which treats exciton-vibrational coupling and exciton-photon coupling on equal footing. When the cavity mode is resonant with the lowest-energy (0-0) transition in the J-aggregate, two polaritons are formed, the lowest-energy polariton (LP) and its higher-energy partner (P1), separated by the Rabi splitting. Strong coupling between the material and cavity modes leads to a decoupling of the exciton and vibrational degrees of freedom and an overall reduction of disorder within the LP. Such effects lead to an expanded material coherence length in the LP which leads to enhanced radiative decay rates. Additional spectral signatures include an amplification of the 0-0 peak coincident with a reduction in the 0-1 peak in the photoluminescence spectrum. It is also shown that the same cavity photon responsible for the LP/P1 splitting causes comparable splittings in the higher vibronic bands due to additional resonances between vibrationally excited states in the electronic ground state manifold and higher energy vibronic excitons.

Endometrial carcinoma in women 40 year old or younger: a case report and literature review.

Endometrial cancer is the most frequent gynecologic cancer. Although it mainly occurs in menopausal women, it can hit younger patients as well. Only few cases of affected women under the age of 30 are reported. A case of a 23-year-old patient with endometrioid carcinoma grade II-III is presented. Hysterectomy is considered the standard treatment and it could represent a problem for those young women who desire to preserve fertility. A conservative management can be offered to these patients when the tumor is well differentiated and advanced stage is excluded. Several studies are available in literature about fertility sparing approach. Progestin treatment, combined or not with hysteroscopic ablation seem to be the most validated conservative management. Anyhow this treatment is not free risk, because it is not always effective and disease progression during or after treatment is possible. Then a strict evaluation and selection of patients before starting treatment is mandatory.

Charge-transfer excitations steer the Davydov splitting and mediate singlet exciton fission in pentacene.

Quantum-chemical calculations are combined to a model Frenkel-Holstein Hamiltonian to assess the nature of the lowest electronic excitations in the pentacene crystal. We show that an admixture of charge-transfer excitations into the lowest singlet excited states form the origin of the Davydov splitting and mediate instantaneous singlet exciton fission by direct optical excitation of coherently coupled single and double exciton states, in agreement with recent experiments.

Wettability control by laser texturing process generating localized gold nanoparticles on polymeric thin films.

In this work a new approach is introduced for surface properties control by laser texturing process. By UV laser irradiation, we are able to control the surface wettability of a chitosan polymeric film in which is introduced a chloroauric acid salt by immersion. Specifically the UV irradiation is responsible for the creation of gold nanoparticles at the irradiated surface of the polymeric film. This photolytic process allows us to localize and design accurately surface patterns and moreover to tune metallic particle size in the range of nanoscale. After the characterization of our gold textured surfaces by atomic force and scanning electron microscopies, we demonstrate the link between wettability surface properties and gold nanoparticles size. The experimental results indicate the influence of the laser intensity, the irradiation time and the polymer film thickness (by increasing the gold concentration) on the gold nanoparticle density and size.

Improvements of optical tactile sensors for robotic system by gold nanocomposite material.

In this work we propose the evolution of a new class of optical pressure sensors suitable for robot tactile sensing. The sensors are based on a tapered optical fiber, where optical signals travel embedded into a PDMS-gold nanocomposite material. By applying different pressure forces on the PDMS-based nanocomposite we measure in real time the change of the optical transmitted intensity due to the coupling between the gold nanocomposite material and the tapered fiber region. The intensity reduction of the transmitted light intensity is correlated with the pressure force magnitude.

Interplay between intrachain and interchain interactions in semiconducting polymer assemblies: the HJ-aggregate model.

A new model for analyzing the photophysics of polymer aggregates is introduced taking into account exciton motion along a polymer chain and across polymer chains. Excitonic coupling and vibronic coupling are treated on equal footing using a Holstein-based Hamiltonian represented in a multi-particle basis set. In the HJ-aggregate model the competition between intrachain (through-bond) coupling leading to Wannier-Mott excitons, and interchain (through-space) coupling leading to Frenkel excitons, is studied in detail for two model dimers: one composed of red-phase polydiacetylene (PDA) chains and the other composed of regioregular P3HT chains. The resulting photophysical properties are shown to depend critically on the relative magnitudes of the intrachain and interchain exciton bandwidths. Dominant intraband (interband) coupling favors a photophysical response resembling J-aggregates (H-aggregates). In PDA dimers, where intrachain coupling prevails, the absorption spectrum is dominated by the 0-0 peak, as is characteristic of J-aggregates. The photoluminescence (PL) spectrum displays hybrid character: the ratio of the main (0-0) band to the first vibronic sideband intensities is initially zero at T = 0 K due to the forbidden nature of the 0-0 transition, but then increases with temperature in a manner characteristic of H-aggregates, peaking when kT ≈ ΔE, where ΔE is the interchain splitting. Further increases in temperature result in a decline of the PL ratio, as in a J-aggregate. This remarkable H to J transition is also predicted for the temperature dependence of the radiative decay rate, k(rad). The maximum (peak) rate scales as, k(rad) (max)∼(W(intra)/W(inter))(1/2), where W(intra) (W(inter)) is the intrachain (interchain) exciton bandwidth. Hence, when W(intra) is sufficiently larger than W(inter) the dimer displays thermally activated superradiance. In P3HT the intrachain coupling is far weaker than in PDA making the intrachain and interchain couplings comparable in the crystalline phase. Although the absorption spectral line shape is still well-accounted for by the conventional H-aggregate model, the photoluminescence is more sensitive, with H or J behavior tunable by changes in morphology. Long range intrachain order which coincides with weaker interchain interactions induces J-aggregate behavior, while short range intrachain order and the resulting stronger interchain coupling induces H-aggregate behavior. Our predictions neatly account for the H-like dominance exhibited by the PL from spin-cast films and the J-like dominance exhibited by the PL from highly ordered P3HT nanofibers self-assembled in toluene.

Radioluminescence of red-emitting Eu-doped phosphors for fiberoptic dosimetry.

Fiberoptic dosimetry (FOD) technique has become an attractive method for real-time dosimetry. Al(2)O(3):Cis one of the most used radioluminescence materials for FOD due to its high efficiency but it presents the drawback of emitting in the spectral region, where spurious luminescence is also important. Optical filtering is the simplest technique to remove spurious luminescence, but is useful when red-emitting scintillators are employed. In this work, the feasibility of using red-emitting Eu-doped phosphors as FOD scintillators has been investigated.

Absorption, circular dichroism, and photoluminescence in perylene diimide bichromophores: polarization-dependent H- and J-aggregate behavior.

Using a single-mode Holstein Hamiltonian with through-space excitonic couplings evaluated quantum mechanically, the absorption, circular dichroism, and photoluminescence spectral line shapes of a chiral perylene diimide dimer complex were accurately reproduced. In general, a dimer consisting of two chromophores related through a C(2) rotation is neither a J- nor an H-aggregate because oscillator strength is divided between the top and bottom of the exciton band. The division gives rise to the two Davydov components per vibronic band in the absorption spectrum. Nevertheless, it is shown that the vibronic structure of the absorption component polarized in the same direction as the lower (upper) Davydov component is identical to what one would obtain from an ideal J- (H-) aggregate. Emission generally contains both polarization components, but the component polarized in the same direction as the lower (upper) Davydov component behaves similarly to the emission from an ideal J- (H-) aggregate. The basic photophysical behavior also applies to molecular crystals containing two molecules per unit cell in which the interactions between inequivalent molecules dominate over interactions between equivalent molecules.