Nanostructured Electrospun Fibers with Self-Assembled Cyclo-L-Tryptophan-L-Tyrosine Dipeptide as Piezoelectric Materials and Optical Second Harmonic Generators.

The potential use of nanostructured dipeptide self-assemblies in materials science for energy harvesting devices is a highly sought-after area of research. Specifically, aromatic cyclo-dipeptides containing tryptophan have garnered attention due to their wide-bandgap semiconductor properties, high mechanical rigidity, photoluminescence, and nonlinear optical behavior. In this study, we present the development of a hybrid system comprising biopolymer electrospun fibers incorporated with the chiral cyclo-dipeptide L-Tryptophan-L-Tyrosine. The resulting nanofibers are wide-bandgap semiconductors (bandgap energy 4.0 eV) consisting of self-assembled nanotubes embedded within a polymer matrix, exhibiting intense blue photoluminescence. Moreover, the cyclo-dipeptide L-Tryptophan-L-Tyrosine incorporated into polycaprolactone nanofibers displays a strong effective second harmonic generation signal of 0.36 pm/V and shows notable piezoelectric properties with a high effective coefficient of 22 pCN-1, a piezoelectric voltage coefficient of geff=1.2 VmN-1 and a peak power density delivered by the nanofiber mat of 0.16µWcm-2. These hybrid systems hold great promise for applications in the field of nanoenergy harvesting and nanophotonics.

A Polymorph of Dipeptide Halide Glycyl-L-Alanine Hydroiodide Monohydrate: Crystal Structure, Optical Second Harmonic Generation, Piezoelectricity and Pyroelectricity.

A polymorph of glycyl-L-alanine HI.H2O is synthesized from chiral cyclo-glycyl-L-alanine dipeptide. The dipeptide is known to show molecular flexibility in different environments, which leads to polymorphism. The crystal structure of the glycyl-L-alanine HI.H2O polymorph is determined at room temperature and indicates that the space group is polar (P21), with two molecules per unit cell and unit cell parameters a = 7.747 Å, b = 6.435 Å, c = 10.941 Å, α = 90°, ß = 107.53(3)°, γ = 90° and V = 520.1(7) Å3. Crystallization in the polar point group 2, with one polar axis parallel to the b axis, allows pyroelectricity and optical second harmonic generation. Thermal melting of the glycyl-L-alanine HI.H2O polymorph starts at 533 K, close to the melting temperature reported for cyclo-glycyl-L-alanine (531 K) and 32 K lower than that reported for linear glycyl-L-alanine dipeptide (563 K), suggesting that although the dipeptide, when crystallized in the polymorphic form, is not anymore in its cyclic form, it keeps a memory of its initial closed chain and therefore shows a thermal memory effect. Here, we report a pyroelectric coefficient as high as 45 µC/m2K occurring at 345 K, one order of magnitude smaller than that of semi-organic ferroelectric triglycine sulphate (TGS) crystal. Moreover, the glycyl-L-alanine HI.H2O polymorph displays a nonlinear optical effective coefficient of 0.14 pm/V, around 14 times smaller than the value from a phase-matched inorganic barium borate (BBO) single crystal. The new polymorph displays an effective piezoelectric coefficient equal to deff=280 pCN-1, when embedded into electrospun polymer fibers, indicating its suitability as an active system for energy harvesting.

Bioinspired Cyclic Dipeptide Functionalized Nanofibers for Thermal Sensing and Energy Harvesting.

Nanostructured dipeptide self-assemblies exhibiting quantum confinement are of great interest due to their potential applications in the field of materials science as optoelectronic materials for energy harvesting devices. Cyclic dipeptides are an emerging outstanding group of ring-shaped dipeptides, which, because of multiple interactions, self-assemble in supramolecular structures with different morphologies showing quantum confinement and photoluminescence. Chiral cyclic dipeptides may also display piezoelectricity and pyroelectricity properties with potential applications in new sources of nano energy. Among those, aromatic cyclo-dipeptides containing the amino acid tryptophan are wide-band gap semiconductors displaying the high mechanical rigidity, photoluminescence and piezoelectric properties to be used in power generation. In this work, we report the fabrication of hybrid systems based on chiral cyclo-dipeptide L-Tryptophan-L-Tryptophan incorporated into biopolymer electrospun fibers. The micro/nanofibers contain self-assembled nano-spheres embedded into the polymer matrix, are wide-band gap semiconductors with 4.0 eV band gap energy, and display blue photoluminescence as well as relevant piezoelectric and pyroelectric properties with coefficients as high as 57 CN-1 and 35×10-6 Cm-2K-1, respectively. Therefore, the fabricated hybrid mats are promising systems for future thermal sensing and energy harvesting applications.

Lead-Free MDABCO-NH4I3 Perovskite Crystals Embedded in Electrospun Nanofibers.

In this work, we introduce lead-free organic ferroelectric perovskite N-methyl-N'-diazabicyclo[2.2.2]octonium)-ammonium triiodide (MDABCO-NH4I3) nanocrystals embedded in three different polymer fibers fabricated by the electrospinning technique, as mechanical energy harvesters. Molecular ferroelectrics offer the advantage of structural diversity and tunability, easy fabrication, and mechanical flexibility. Organic-inorganic hybrid materials are new low-symmetry emerging materials that may be used as energy harvesters because of their piezoelectric or ferroelectric properties. Among these, ferroelectric metal-free perovskites are a class of recently discovered multifunctional materials. The doped nanofibers, which are very flexible and have a high Young modulus, behave as active piezoelectric energy harvesting sources that produce a piezoelectric voltage coefficient up to geff = 3.6 VmN-1 and show a blue intense luminescence band at 325 nm. In this work, the pyroelectric coefficient is reported for the MDABCO-NH4I3 perovskite inserted in electrospun fibers. At the ferroelectric-paraelectric phase transition, the embedded nanocrystals display a pyroelectric coefficient as high as 194 × 10-6 Cm-2k-1, within the same order of magnitude as that reported for the state-of-the-art bulk ferroelectric triglycine sulfate (TGS). The perovskite nanocrystals embedded into the polymer fibers remain stable in their piezoelectric output response, and no degradation is caused by oxidation, making the piezoelectric perovskite nanofibers suitable to be used as flexible energy harvesters.

High Piezoelectric Output Voltage from Blue Fluorescent N,N-Dimethyl-4-nitroaniline Nano Crystals in Poly-L-Lactic Acid Electrospun Fibers.

N,N-dimethyl-4-nitroaniline is a piezoelectric organic superplastic and superelastic charge transfer molecular crystal that crystallizes in an acentric structure. Organic mechanical flexible crystals are of great importance as they stand between soft matter and inorganic crystals. Highly aligned poly-l-lactic acid polymer microfibers with embedded N,N-dimethyl-4-nitroaniline nanocrystals are fabricated using the electrospinning technique, and their piezoelectric and optical properties are explored as hybrid systems. The composite fibers display an extraordinarily high piezoelectric output response, where for a small stress of 5.0 × 103 Nm-2, an effective piezoelectric voltage coefficient of geff = 4.1 VmN-1 is obtained, which is one of the highest among piezoelectric polymers and organic lead perovskites. Mechanically, they exhibit an average increase of 67% in the Young modulus compared to polymer microfibers alone, reaching 55 MPa, while the tensile strength reaches 2.8 MPa. Furthermore, the fibers show solid-state blue fluorescence, important for emission applications, with a long lifetime decay (147 ns) lifetime decay. The present results show that nanocrystals from small organic molecules with luminescent, elastic and piezoelectric properties form a mechanically strong hybrid functional 2-dimensional array, promising for applications in energy harvesting through the piezoelectric effect and as solid-state blue emitters.

Discovery of amivantamab (JNJ-61186372), a bispecific antibody targeting EGFR and MET.

A bispecific antibody (BsAb) targeting the epidermal growth factor receptor (EGFR) and mesenchymal-epithelial transition factor (MET) pathways represents a novel approach to overcome resistance to targeted therapies in patients with non-small cell lung cancer. In this study, we sequentially screened a panel of BsAbs in a combinatorial approach to select the optimal bispecific molecule. The BsAbs were derived from different EGFR and MET parental monoclonal antibodies. Initially, molecules were screened for EGFR and MET binding on tumor cell lines and lack of agonistic activity toward MET. Hits were identified and further screened based on their potential to induce untoward cell proliferation and cross-phosphorylation of EGFR by MET via receptor colocalization in the absence of ligand. After the final step, we selected the EGFR and MET arms for the lead BsAb and added low fucose Fc engineering to generate amivantamab (JNJ-61186372). The crystal structure of the anti-MET Fab of amivantamab bound to MET was solved, and the interaction between the two molecules in atomic details was elucidated. Amivantamab antagonized the hepatocyte growth factor (HGF)-induced signaling by binding to MET Sema domain and thereby blocking HGF ß-chain-Sema engagement. The amivantamab EGFR epitope was mapped to EGFR domain III and residues K443, K465, I467, and S468. Furthermore, amivantamab showed superior antitumor activity over small molecule EGFR and MET inhibitors in the HCC827-HGF in vivo model. Based on its unique mode of action, amivantamab may provide benefit to patients with malignancies associated with aberrant EGFR and MET signaling.

Anisotropic PCL nanofibers embedded with nonlinear nanocrystals as strong generators of polarized second harmonic light and piezoelectric currents.

Using the electrospinning technique nanofibers consisting of organic nonlinear optical 3-nitroaniline (3NA, C6H6N2O2) nanocrystals embedded in poly-ε-caprolactone (PCL) polymer, 3NA@PCL nanofibers, were produced. Polarimetry optical second harmonic generation and X-ray diffraction studies show that 3NA push-pull molecules crystallize inside the polymer fibers with a strong preferential orientation giving rise to an alignment of the molecular dipole moments along the nanofibers longitudinal axis. This alignment strongly enhances the second order nonlinear optical response of the fibers. Intense second harmonic generation emission was observed from a single nanofiber, corresponding to an effective second order susceptibility of 80 pm V-1, four times greater than the largest second order susceptibility tensor element (21 pm V-1) associated with a macroscopic 3NA crystal. Moreover, when subjected to a modest periodically applied force of 3 N, a piezoelectric current of 70 nA generated by a 4 cm2 electrospun nanofiber mat amounted to 122 nW cm-2 of instantaneous density power, sufficient to power a LCD display. The results show that the electrospinning technique is a powerful technique to fabricate organic functional materials with oriented nanocrystals made of highly polarizable molecules, embedded in a polymer matrix.

Regeneration of Diabetic Foot Ulcers Based on Therapy with Red LED Light and a Natural Latex Biomembrane.

This study analyzes the effects of the Rapha® system, which employs red light therapy (RLT) and a natural latex biomembrane in the healing of neuropathic ulcers associated with the diabetic foot. We conducted a randomized, controlled, blinded clinical trial with 15 participants that were divided into three groups (GI, GII and GIII): (i) Rapha® system application by the participant and a health professional at home, with clinical status evaluation every 2 weeks at the hospital (GI); (ii) standard protocol used in Brazil, performed by a health professional at the hospital (GII; control); and (iii) the Rapha® system applied by the participant at home and clinical status evaluation every 2 weeks at the hospital (GIII). We used image processing techniques on photographic recordings of the lesions, and several statistical tests were used to analyze the data, allowing for the comparison of the average results for all groups. The average healing rates of GI, GII, and GIII were 77.0, 51.4, and 80%, respectively. The granulation tissue evaluation indicated a higher efficacy in the tissue repair of lesions treated with the Rapha® system. In conclusion, the Rapha® system proved to be an effective healing system, even when self-applied at the patient's home.

Self-assembly of dipeptide Boc-diphenylalanine nanotubes inside electrospun polymeric fibers with strong piezoelectric response.

Dipeptide biomaterials are strong piezoelectric materials that can convert applied mechanical forces into electricity. We have developed large-scale hybrid electrospun arrays containing N-tert-butoxycarbonyl (Boc) diphenylalanine in the form of nanotubes embedded in biocompatible polymers. These nanofibers exhibit strong piezoelectric properties when a periodic mechanical force is applied. The nanostructured hybrid materials were produced by the electrospinning technique. Optical absorption measurements show four bands in the spectral region 240-280 nm indicating quantum confinement due to nanotube formation of Boc-diphenylalanine in dichloromethane solutions. A strong blue photoluminescence emission was observed from nanotubes crystallized inside the fiber arrays during the electrospinning process. These two dimensional hybrid biomaterial structures are able to generate voltage, current and density power of up to 30 V, 300 nA and 2.3 µW cm-2, respectively, when a periodical force of 1.5 N is applied. The dipeptide-polymer electrospun arrays can power several liquid-crystal display panels and may be used for biomedical applications and as bio-energy sources.

Corpus callosum diffusion abnormalities in refractory epilepsy associated with hippocampal sclerosis.

OBJECTIVES: To detect by diffusion tensor imaging (DTI) the extent of microstructural integrity changes of the corpus callosum (CC) in patients with hippocampal sclerosis (HS) and to evaluate possible association with clinical characteristics. METHODS: Fourty-two patients with temporal lobe epilepsy (TLE) and HS and 30 control subjects were studied with DTI. We grouped patients according to lesion side (left or right) HS. Mean diffusivity (MD), fractional anisotropy (FA), radial (RD) and axial diffusivity (AD) were extracted from five segments in CC midsagittal section obtained by automatic segmentation. CC DTI findings were compared between groups. We also evaluated association of DTI changes and clinical characteristics. RESULTS: HS patients displayed decreased FA and increased MD and RD in the anterior, mid-posterior and posterior CC segments, compared to controls. No differences were observed in AD. Patients reporting febrile seizure as the initial precipitating event presented more intense diffusion changes. No differences were seen comparing left and right HS. Age at epilepsy onset, disease duration and seizure frequency were not associated with DTI findings. CONCLUSIONS: This is one of the largest series of TLE-HS patients evaluating CC white matter fiber integrity by DTI, which allowed us to study how some clinical characteristics, such as seizure frequency, disease duration and lesion side, are related to CC integrity. Occurrence of febrile seizure was the only factor that had significant impact on tract integrity. Diffusion changes were not restricted to the posterior part of the CC; we observed the same changes for the anterior part of the CC. Diffusion changes were characterized by an increase in RD, while the AD remained intact for all regions of the CC.

Engineering a targeted delivery platform using Centyrins.

Targeted delivery of therapeutic payloads to specific tissues and cell types is an important component of modern pharmaceutical development. Antibodies or other scaffold proteins can provide the cellular address for delivering a covalently linked therapeutic via specific binding to cell-surface receptors. Optimization of the conjugation site on the targeting protein, linker chemistry and intracellular trafficking pathways can all influence the efficiency of delivery and potency of the drug candidate. In this study, we describe a comprehensive engineering experiment for an EGFR binding Centyrin, a highly stable fibronectin type III (FN3) domain, wherein all possible single-cysteine replacements were evaluated for expression, purification, conjugation efficiency, retention of target binding, biophysical properties and delivery of a cytotoxic small molecule payload. Overall, 26 of the 94 positions were identified as ideal for cysteine modification, conjugation and drug delivery. Conjugation-tolerant positions were mapped onto a crystal structure of the Centyrin, providing a structural context for interpretation of the mutagenesis experiment and providing a foundation for a Centyrin-targeted delivery platform.

Imidazoanthraquinone derivatives for the chromofluorogenic sensing of basic anions and trivalent metal cations.

Four imidazoanthraquinone derivatives (2a-d) were synthesized and characterized and their coordination behavior against selected anions and cations tested. Acetonitrile solutions of probes showed charge-transfer absorptions in the 407-465 nm range. The four probes emitted in the 533-571 nm interval. The recognition ability of 2a-d was evaluated in the presence of F(-), Cl(-), Br(-), I(-), OCN(-), BzO(-), ClO4(-), AcO(-), HSO4(-), H2PO4(-), and CN(-). Only F(-), AcO(-), and H2PO4(-) induced a new red-shifted absorption band that was attributed to a deprotonation process involving the amine moiety of the imidazole ring. Moreover, upon increasing quantities of F(-), AcO(-), and H2PO4(-), moderate quenching was induced in the emission of 2a-d together with the appearance of a new red-shifted band. The UV-visible and emission behavior of the four probes in the presence of Cu(2+), Co(2+), Mg(2+), Fe(3+), Ba(2+), Fe(2+), Ni(2+), Ca(2+), Zn(2+), Pb(2+), Cd(2+), Cr(3+), Al(3+), K(+), and Li(+) was also assessed. Only addition of Fe(3+), Cr(3+), and Al(3+) caused a new blue-shifted band in 2a-d that was ascribed to a preferential coordination with the acceptor part of the probes. Moreover, an important quenching of the emission was observed which was ascribed to the interaction between these trivalent cations and 2a-d.

Synthesis and solvatochromism studies of novel bis(indolyl)methanes bearing functionalized arylthiophene groups as new colored materials.

The demand for dyes with solvatochromic properties has increased in the last few years, mainly due to their wide range of applications in the analytical and industrial fields, such as in the textile industry. The phenomenon of solvatochromism is associated with the differential solvation of the ground and excited states of the solvatochromic compounds, leading to an important tool for the study of the nature of solute-solvent interactions. In this paper we report the synthesis of new bis(indolyl)methane derivatives bearing arylthiophene spacers (2a-d) functionalized with electron-donating and electron-withdrawing groups, and the photophysical studies in different solvents, such as ethanol, acetonitrile, dichloromethane, trichloromethane, dimethylsulfoxide, diethylether and 1,4-dioxane. Aiming to explore their solvatochromic behaviour in the ground and excited states, all solvents employed have different hydrogen-bond donor abilities. The largest colour modifications were visualized for compound 2b, the solution colours of which are orange in DMSO, blue in trichloromethane, green in dichloromethane and purple in 1,4-dioxane. A negative solvatochromism was observed in 2b and a positive one in 2a, 2c and 2d.

Triphenylamine-benzimidazole derivatives: synthesis, excited-state characterization, and DFT studies.

The synthesis and comprehensive characterization of the excited states of four novel triphenylamine-benzimidazole derivatives has been undertaken in solution (ethanol and methylcyclohexane) at room temperature. This includes the determination of the absorption, fluorescence, and triplet-triplet absorption spectra, together with quantum yields of fluorescence, internal conversion, intersystem crossing, and singlet oxygen. From the overall data the radiative and radiationless rate constants could be obtained, and it is shown that the compounds are highly emissive with the radiative decay dominating, with more than 70% of the quanta loss through this deactivation channel. The basic structure of the triphenylamine-benzimidazole derivatives (1a) was modified at position 5 of the heterocyclic moiety with electron-donating (OH (1b), OCH3 (1c)) or electron-withdrawing groups (CN, (1d)). It was found that the photophysical properties remain basically unchanged with the different substitutions, although a marked Stokes shift was observed with 1d. The presence and nature of a charge-transfer transition is discussed with the help of theoretical (DFT and TDFT) data. All compounds displayed exceptionally high thermal stability (between 399 and 454 °C) as seen by thermogravimetric analysis.

Synthesis and evaluation of thiosemicarbazones functionalized with furyl moieties as new chemosensors for anion recognition.

A family of heterocyclic thiosemicarbazone dyes (3a-f and 4) containing furyl groups was synthesized in good yields, characterized and their response in acetonitrile in the presence of selected anions was studied. Acetonitrile solutions of 3a-f and 4 showed absorption bands in the 335-396 nm range which are modulated by the electron donor or acceptor strength of the heterocyclic systems appended to the thiosemicarbazone moiety. Fluoride, chloride, bromide, iodide, dihydrogen phosphate, hydrogen sulphate, nitrate, acetate and cyanide anions were used in recognition studies. From these anions, only sensing features were seen for fluoride, cyanide, acetate and dihydrogen phosphate. Two clearly different chromo-fluorogenic behaviours were observed: (i) a small shift of the absorption band due to the coordination of the anions with the thiourea protons and (ii) the appearance of a new red shifted band due to deprotonation. For the latter effect, a change in the colour of solution from pale yellow to purple was observed. Fluorescence studies were also in agreement with the different effects observed in the UV/Vis titrations. In this case, hydrogen bonding interactions were visible through the enhancement of the emission band, whereas deprotonation induced the appearance of a new red-shifted emission. Logarithms of stability constants for the two processes (complex formation + deprotonation) for receptors in the presence of fluoride and acetate anions were determined from spectrophotometric titrations using the HypSpec V1.1.18 program. Semi-empirical calculations to evaluate the hydrogen-donating ability of the receptors and a prospective electrochemical characterization of compound in the presence of fluoride were also performed.

Mine water treatment with limestone for sulfate removal.

Limestone can be an option for sulfate sorption, particularly from neutral mine drainages because calcium ions on the solid surface can bind sulfate ions. This work investigated sulfate removal from mine waters through sorption on limestone. Continuous stirred-tank experiments reduced the sulfate concentration from 588.0mg/L to 87.0mg/L at a 210-min residence time. Batch equilibrium tests showed that sulfate loading on limestone can be described by the Langmuir isotherm, with a maximum loading of 23.7mg/g. Fixed-bed experiments were utilized to produce breakthrough curves at different bed depths. The Bed Depth Service Time (BDST) model was applied, and it indicated sulfate loadings of up to 20.0gSO(4)(2-)/L-bed as the flow rate increased from 1 to 10mL/min. Thomas, Yoon-Nelson and dose-response models, predicted a maximum particle loading of 19mg/g. Infrared spectrometry indicated the presence of sulfate ions on the limestone surface. Sulfate sorption on limestone seems to be an alternative to treating mine waters with sulfate concentrations below the 1200-2000mg/L range, where lime precipitation is not effective. In addition, this approach does not require alkaline pH values, as in the ettringite process.

Phosphorus magnetic resonance spectroscopy in malformations of cortical development.

PURPOSE: The aim of this study was to evaluate phospholipid metabolism in patients with malformations of cortical development (MCDs). METHODS: Thirty-seven patients with MCDs and 31 control subjects were studied using three-dimensional phosphorus magnetic resonance spectroscopy ((31)P-MRS) at 3.0 T. The voxels in the lesions and in the frontoparietal cortex of the control subjects were compared (the effective volumes were 12.5 cm(3)). Robust quantification methods were applied to fit the time-domain data to the following resonances: phosphoethanolamine (PE); phosphocholine (PC); inorganic phosphate (Pi); glycerophosphoethanolamine (GPE); glycerophosphocholine (GPC); phosphocreatine (PCr); and α-, ß-, and γ-adenosine triphosphate (ATP). We also estimated the total ATP (ATP(t) = α-+ß-+γ-ATP), phosphodiesters (PDE = GPC+GPE), phosphomonoesters (PME = PE+PC), and the PME/PDE, PCr/ATP(t) and PCr/Pi ratios. The magnesium (Mg(2+)) levels and pH values were calculated based on PCr, Pi, and ß-ATP chemical shifts. KEY FINDINGS: Compared to controls and assuming that a p-value < 0.05 indicates statistical significance, the patients with MCDs exhibited significantly lower pH values and higher Mg(2+) levels. In addition, the patients with MCDs had lower GPC and PDE and an increased PME/PDE ratio. SIGNIFICANCE: Mg(2+) and pH are important in the regulation of bioenergetics and are involved in many electrical activity pathways in the brain. Our data support the idea that neurometabolic impairments occur during seizure onset and propagation. The GPC, PDE, and PME/PDE abnormalities also demonstrate that there are membrane turnover disturbances in patients with MCDs.

(Oligo)thienyl-imidazo-benzocrown ether derivatives: synthesis, photophysical studies and evaluation of their chemosensory properties.

A series of novel (oligo)thienyl-imidazo-benzocrown ethers were synthesised through a simple method and evaluated as fluorimetric chemosensors for transition metal cations. Interaction with Ni(2+), Pd(2+), and Hg(2+) in ACN/DMSO solution (99:1) was studied by absorption and emission spectroscopy. Chemoselectivity studies in the presence of Na(+) were also carried out and a fluorescence enhancement upon chelation (CHEF) effect was observed following Hg(2+) complexation. Considering that most systems using fluorescence spectroscopy for detecting Hg(2+) are based on the complexation enhancement of the fluorescence quenching (CHEQ) effect, the present work represents one of the few examples for sensing of Hg(2+) based on a CHEF effect.

Detection of Leishmania (Leishmania) infantum RNA in fleas and ticks collected from naturally infected dogs.

The occurrence of the insect vector (sand flies) with low rates of Leishmania infection, as well as autochthonous transmission in the absence of the natural vector in dogs, have been reported. These unexpected data suggest a hypothesis of other arthropods as a possible way of Leishmania transmission. The prevalence of Leishmania (Leishmania) infantum in fleas and ticks collected from dogs with canine visceral leishmaniasis (CVL), as well as parasite viability, were evaluated herein. The presence of L. (L.) infantum was assayed by PCR and ELISA in ectoparasites and biological samples from 73 dogs living in a Brazilian endemic area. As the occurrence of Leishmania DNA in ticks and fleas is expected given their blood-feeding habits, we next investigated whether parasites can remain viable inside ticks. PCR and ELISA confirmed that 83% of the dogs had CVL. Fleas and ticks (nymphs, male and female adults) were collected in 55% and 63% of the 73 dogs, respectively. Out of the 60 dogs with CVL, 80% harbored ectoparasites infected with L. (L.) infantum. The infection rates of the ectoparasites were 23% and 50% for fleas and ticks, respectively. The RNA analysis of the extract from ticks left in laboratory conditions during 7 to 10 days after removal from CVL dogs showed that parasites were alive. In addition, live parasites were also detected inside adult ticks recently molted in laboratory conditions. These findings indicate a higher infection rate of L. (L.) infantum in ticks and fleas, but they do not conclusively demonstrate whether these ticks can act as vectors of CVL, despite the fact that their rates were higher than those previously described in Lutzomyia longipalpis. The presence of viable L. (L.) infantum in ticks suggests the possible importance of dog ectoparasites in CVL dissemination.

Exploring the emissive properties of new azacrown compounds bearing aryl, furyl, or thienyl moieties: a special case of chelation enhancement of fluorescence upon interaction with Ca(2+), Cu(2+), or Ni(2+).

Three new compounds bearing furyl, aryl, or thienyl moieties linked to an imidazo-crown ether system (1, 2, and 3) were synthesized and fully characterized by elemental analysis, infrared, UV-vis absorption, and emission spectroscopy, X-ray crystal diffraction, and MALDI-TOF-MS spectrometry. The interaction toward metal ions (Ca(2+), Cu(2+), Ni(2+), and Hg(2+)) and F(-) has been explored in solution by absorption and fluorescence spectroscopy. Mononuclear and binuclear metal complexes using Cu(2+) or Hg(2+) as metal centers have been synthesized and characterized. Compounds 2 and 3 show a noticeable enhancement of the fluorescence intensity in the presence of Ca(2+) and Cu(2+) ions. Moreover compound 3 presents a dual sensory detection way by modification of the fluorimetric and colorimetric properties in the presence of Cu(2+) or Hg(2+). EPR studies in frozen solution and in microcrystalline state of the dinuclear Cu(II)3 complex revealed the presence of an unique Cu(2+) type.