A single dose of angiotensin-(1-7) resolves eosinophilic inflammation and protects the lungs from a secondary inflammatory challenge.

OBJECTIVE: Angiotensin-(1-7) [Ang-(1-7)] is a pro-resolving mediator. It is not known whether the pro-resolving effects of Ang-(1-7) are sustained and protect the lung from a subsequent inflammatory challenge. This study sought to investigate the impact of treatment in face of a second allergic or lipopolysaccharide (LPS) challenge. METHODS: Mice, sensitized and challenged with ovalbumin (OVA), received a single Ang-(1-7) dose at the peak of eosinophilic inflammation, 24 h after the final OVA challenge. Subsequently, mice were euthanized at 48, 72, 96, and 120 h following the OVA challenge, and cellular infiltrate, inflammatory mediators, lung histopathology, and macrophage-mediated efferocytic activity were evaluated. The secondary inflammatory stimulus (OVA or LPS) was administered 120 h after the last OVA challenge, and subsequent inflammatory analyses were performed. RESULTS: Treatment with Ang-(1-7) resulted in elevated levels of IL-10, CD4+Foxp3+, Mres in the lungs and enhanced macrophage-mediated efferocytic capacity. Moreover, in allergic mice treated with Ang-(1-7) and then subjected to a secondary OVA challenge, inflammation was also reduced. Similarly, in mice exposed to LPS, Ang-(1-7) effectively prevented the lung inflammation. CONCLUSION: A single dose of Ang-(1-7) resolves lung inflammation and protect the lung from a subsequent inflammatory challenge highlighting its potential therapeutic for individuals with asthma.

Objective assessment of simulated non-carious cervical lesion by tridimensional digital scanning.

OBJECTIVE: To explore the use of 3D intraoral scanner/image analysis for the detection and monitoring of simulated non-carious cervical lesions (NCCLs) in vitro. MATERIALS AND METHODS: A total of 288 NCCLs of different severities and simulated using a laboratorial model associating toothbrush stiffness (soft, medium, and hard) and toothpaste abrasivity (low, medium, high, and negative control) were analyzed. Dental impressions were taken from specimens before and after 35K and 65K brushing strokes, and then scanned with a CEREC Omnicam scanner. 3D models were analyzed for volumetric tooth loss. 3D optical profilometry was considered as the gold standard. Data were analyzed using ANOVA and Fisher's PLSD tests (alpha = 0.05), and agreement between methods by using intraclass correlation coefficient. RESULTS: Toothbrushes of hard and mid stiffness caused higher tooth loss than soft when associated with the highest abrasive, at 35K and 65K strokes (p < 0.001). Variation in slurry abrasivity led to differences in tooth loss (with control < low < medium < high, p < 0.0001) after both 35K and 65K strokes, regardless of the type of toothbrush used, except at 35K, wherein control = low (p = 0.55). 35K strokes caused less tooth loss than 65K for all abrasive slurries (p < 0.0001) except controls. The intraclass correlation coefficient for agreement between the test and gold standard methods was 0.85. CONCLUSIONS: Analysis of 3D images from intraoral scanner could detect and monitor NCCL progression, although this ability was limited on incipient lesions. Overall good agreement was found between the test method and optical profilometry. CLINICAL RELEVANCE: The suggested method may be applicable to detect and monitor NCCLs clinically.

Persistent organic pollutants: The trade-off between potential risks and sustainable remediation methods.

Persistent Organic Pollutants (POPs) have become a very serious issue for the environment because of their toxicity, resistance to conventional degradation mechanisms, and capacity to bioconcentrate, bioaccumulate and biomagnify. In this review article, the safety, regulatory, and remediation aspects of POPs including aromatic, chlorinated, pesticides, brominated, and fluorinated compounds, are discussed. Industrial and agricultural activities are identified as the main sources of these harmful chemicals, which are released to air, soil and water, impacting on social and economic development of society at a global scale. The main types of POPs are presented, illustrating their effects on wildlife and human beings, as well as the ways in which they contaminate the food chain. Some of the most promising and innovative technologies developed for the removal of POPs from water are discussed, contrasting their advantages and disadvantages with those of more conventional treatment processes. The promising methods presented in this work include bioremediation, advanced oxidation, ionizing radiation, and nanotechnology. Finally, some alternatives to define more efficient approaches to overcome the impacts that POPs cause in the hydric sources are pointed out. These alternatives include the formulation of policies, regulations and custom-made legislation for controlling the use of these pollutants.

Neuroprotection by post-stroke administration of an oral formulation of angiotensin-(1-7) in ischaemic stroke.

NEW FINDINGS: What is the central question of this study? Angiotensin-(1-7) decreases cerebral infarct volume and improves neurological function when delivered centrally before and during ischaemic stroke. Here, we assessed the neuroprotective effects of angiotensin-(1-7) when delivered orally post-stroke. What is the main finding and its importance? We show that oral delivery of angiotensin-(1-7) attenuates cerebral damage induced by middle cerebral artery occlusion in rats, without affecting blood pressure or cerebral blood flow. Importantly, these treatments begin post-stroke at times coincident with the treatment window for tissue plasminogen activator, providing supporting evidence for clinical translation of this new therapeutic strategy. ABSTRACT: As a target for stroke therapies, the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas [ACE2/Ang-(1-7)/Mas] axis of the renin-angiotensin system can be activated chronically to induce neuroprotective effects, in opposition to the deleterious effects of angiotensin II via its type 1 receptor. However, more clinically relevant treatment protocols with Ang-(1-7) that involve its systemic administration beginning after the onset of ischaemia have not been tested. In this study, we tested systemic post-stroke treatments using a molecule where Ang-(1-7) is included within hydroxypropyl-ß-cyclodextrin [HPßCD-Ang-(1-7)] as an orally bioavailable treatment. In three separate protocols, HPßCD-Ang-(1-7) was administered orally to Sprague-Dawley rats after induction of ischaemic stroke by endothelin-1-induced middle cerebral artery occlusion: (i) to assess its effects on cerebral damage and behavioural deficits; (ii) to determine its effects on cardiovascular parameters; and (iii) to determine whether it altered cerebral blood flow. The results indicate that post-stroke oral administration of HPßCD-Ang-(1-7) resulted in 25% reductions in cerebral infarct volumes and improvement in neurological functions (P < 0.05), without inducing any alterations in blood pressure, heart rate or cerebral blood flow. In conclusion, Ang-(1-7) treatment using an oral formulation after the onset of ischaemia induces significant neuroprotection in stroke and might represent a viable approach for taking advantage of the protective ACE2/Ang-(1-7)/Mas axis in this disease.

Chronic oral administration of Ang-(1-7) improves skeletal muscle, autonomic and locomotor phenotypes in muscular dystrophy.

Muscular dystrophies are a group of heterogeneous genetic disorders that cause progressive muscle weakness and wasting, dilated cardiomyopathy and early mortality. There are different types of muscular dystrophies with varying aetiologies but they all have a common hallmark of myofibre degeneration, atrophy and decreased mobility. Mutation in Sgcd (sarcoglycan-δ), a subunit of dystrophin glycoprotein complex, causes LGMD2F (limb girdle muscular dystrophy 2F). Previously, we have reported that Sgcd-deficient (Sgcd-/-) mice exhibit AngII (angiotensin II)-induced autonomic and skeletal muscle dysfunction at a young age, which contributes to onset of dilated cardiomyopathy and mortality at older ages. Two counter-regulatory RAS (renin-angiotensin system) pathways have been identified: deleterious actions of AngII acting on the AT1R (AngII type 1 receptor) compared with the protective actions of Ang-(1-7) [angiotensin-(1-7)] acting on the receptor Mas. We propose that the balance between the AngII/AT1R and Ang-(1-7)/Mas axes is disturbed in Sgcd-/- mice. Control C57BL/6J and Sgcd-/- mice were treated with Ang-(1-7) included in hydroxypropyl ß-cyclodextrin (in drinking water) for 8-9 weeks beginning at 3 weeks of age. Ang-(1-7) treatment restored the AngII/AT1R compared with Ang-(1-7)/Mas balance, decreased oxidative stress and fibrosis in skeletal muscle, increased locomotor activity, and prevented autonomic dysfunction without lowering blood pressure in Sgcd-/- mice. Our results suggest that correcting the early autonomic dysregulation by administering Ang-(1-7) or enhancing its endogenous production may provide a novel therapeutic approach in muscular dystrophy.

Disentangling doping and strain effects at defects of grown MoS2 monolayers with nano-optical spectroscopy.

The role of defects in two-dimensional semiconductors and how they affect the intrinsic properties of these materials have been a widely researched topic over the past few decades. Optical characterization techniques such as photoluminescence and Raman spectroscopies are important tools to probe the physical properties of semiconductors and the impact of defects. However, confocal optical techniques present a spatial resolution limitation lying in a µm-scale, which can be overcome by the use of near-field optical measurements. Here, we use tip-enhanced photoluminescence and Raman spectroscopies to unveil the nanoscale optical properties of grown MoS2 monolayers, revealing that the impact of doping and strain can be disentangled by the combination of both techniques. A noticeable enhancement of the exciton peak intensity corresponding to trion emission quenching is observed at narrow regions down to a width of 47 nm at grain boundaries related to doping effects. Besides, localized strain fields inside the sample lead to non-uniformities in the intensity and energy position of photoluminescence peaks. Finally, two distinct MoS2 samples present different nano-optical responses at their edges associated with opposite strains. The edge of the first sample shows a photoluminescence intensity enhancement and energy blueshift corresponding to a frequency blueshift for E2g and 2LA Raman modes. In contrast, the other sample displays a photoluminescence energy redshift and frequency red shifts for E2g and 2LA Raman modes at their edges. Our work highlights the potential of combining tip-enhanced photoluminescence and Raman spectroscopies to probe localized strain fields and doping effects related to defects in two-dimensional materials.

An oral formulation of angiotensin-(1-7) reverses corpus cavernosum damages induced by hypercholesterolemia.

INTRODUCTION: The renin angiotensin system plays a crucial role in erectile function. It has been shown that elevated angiotensin-II levels contribute to the development of erectile dysfunction (ED). Oppositely, angiotensin-(1-7) (Ang-[1-7]) mediates penile erection by activation of receptor Mas. Recently, we have developed a formulation based on Ang-(1-7) inclusion in cyclodextrin (CyD) [Ang-(1-7)-CyD], which allows for the oral administration of Ang-(1-7). AIM: In the present study, we evaluated the effects of chronic treatment with Ang-(1-7)-CyD on penile fibrosis, oxidative stress, and endothelial function in hypercholesterolemic mice. METHODS: Apolipoprotein(Apo)E-/- mice fed a Western-type diet for 11 weeks received Ang-(1-7)-CyD or vehicle during the final 3 weeks. Collagen content and reactive oxygen species (ROS) production within the corpus cavernosum were evaluated by Sirius red and dihydroethidium staining, respectively. Protein expression of neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS), nicotinamide adenine dinucleotide phosphate (NADPH) subunits (p67-phox and p22-phox), and AT1 and Mas receptors in the penis was assessed by Western blotting. Nitric oxide (NO) production was measured by Griess assay in the mice serum. Cavernosal strips were mounted in an isometric organ bath to evaluate the endothelial function. MAIN OUTCOME MEASURES: The effect of Ang-(1-7)-CyD treatment on penile fibrosis, oxidative stress, and endothelial function in hypercholesterolemia-induced ED. RESULTS: Ang-(1-7)-CyD treatment reduced collagen content in the corpus cavernosum of ApoE-/- mice. This effect was associated with an attenuation of ROS production and a diminished expression of NADPH. Furthermore, Ang-(1-7)-CyD treatment augmented the expression of nNOS and eNOS in the penis and elevated vascular NO production. Importantly, these effects were accompanied by an improvement in cavernosal endothelial function. CONCLUSION: Long-term treatment with Ang-(1-7)-CyD reduces penile fibrosis associated with attenuation of oxidative stress. Additionally, cavernosal endothelial function in hypercholesterolemic mice was markedly improved. These results suggest that Ang-(1-7)-CyD might have significant therapeutic benefits for the treatment of erectile dysfunction.

Prior Restorative Procedures to Endodontic Treatment.

Tooth loss due to fracture and the failure of endodontic treatment (ET) are common situations in teeth with extensive tissue destruction. This is due to the fragility of the remaining dental structure and the difficulty in sealing cavities, which is sometimes associated with the violation of the supracrestal insertion tissue. The previous restoration of marginal ridges or cusps with composite resin (CR) restores their fracture resistance, due to the adhesive characteristics of the restorative material, while also protecting the quality of endodontic treatment through better sealing. However, the protocol adopted in teeth requiring endodontic treatment involves performing the restorative procedure only after the endodontic procedures. The objective of this study was to report a case in which restoration of marginal ridges and/or cusps was performed prior to endodontic treatment, focusing on maintaining the tooth in function without dental fracture. The restoration was performed with an inverted operative sequence before the endodontic treatment. There was a violation of the supracrestal insertion tissue, requiring crown lengthening surgery (CLS) prior to the restorative procedure. Clinical and radiographic evaluations were performed postoperatively at seven days, three, six, and nine months, and five years. Tooth function was maintained without dental fractures or restoration loss. Periradicular space healing occurred with the disappearance of the lesion. Performing the restorative procedure prior to endodontic treatment in teeth with extensive coronal destruction is an alternative technique that facilitates clinical procedures, reduces the likelihood of dental loss due to fracture, and promotes endodontic treatment success.

Combining Polymer and Cyclodextrin Strategy for Drug Release of Sulfadiazine from Electrospun Fibers.

This study reports the fabrication of polymeric matrices through electrospinning using polymethyl methacrylate (PMMA) and poly(lactic-co-glycolic acid) (PLGA), biocompatible polymers commonly used in medical systems. These polymers were combined with an antibacterial drug, sulfadiazine sodium salt (SDS) or its supramolecular system formed with hydroxypropyl-ß-cyclodextrin (HPß/CD) at 1:1 molar ratio, aiming to assemble a transdermal drug delivery system. The formation of fibers was confirmed by scanning electron microscopy (SEM), and the fibers' surface properties were analyzed using contact angle and water vapor permeability techniques. Drug release tests and cell viability assays were performed to evaluate the potential toxicity of the material. SEM images demonstrated that the obtained fibers had nanoscale- and micrometer-scale diameters in PLGA and PMMA systems, respectively. The contact angle analyses indicated that, even in the presence of hydrophilic molecules (SDS and HPßCD), PMMA fibers exhibited hydrophobic characteristics, while PLGA fibers exhibited hydrophilic surface properties. These data were also confirmed by water vapor permeability analysis. The drug release profiles demonstrated a greater release of SDS in the PLGA system. Moreover, the presence of HPßCD improved the drug release in both polymeric systems and the cell viability in the PMMA SDS/HPßCD system. In terms of antibacterial activity, all membranes yielded positive outcomes; nevertheless, the PLGA SDS/HPßCD membrane exhibited the most remarkable results, with the lowest microbial load values. Additionally, the pseudo wound healing analysis demonstrated that the PLGA SDS/HPßCD fiber exhibited results similar to the control group. Consequently, these findings exemplify the substantial potential of the obtained materials for use in wound healing applications.

Ultrafast hot electron-hole plasma photoluminescence in two-dimensional semiconductors.

The transition metal dichalcogenide family of semiconducting two-dimensional materials has recently shown a prominent potential to be an ideal platform to study the exciton Mott transition into electron-hole plasma and liquid phases due to their strong Coulomb interactions. Here, we show that pulsed laser excitation at high pump fluences can induce this exciton Mott transition to an electron-hole plasma in mono and few-layer transition metal dichalcogenides at room temperature. The formation of an electron-hole plasma leads to a broadband light emission spanning from the near infrared to the visible region. In agreement with our theoretical calculations, the photoluminescence emission at high energies displays an exponential decay that directly reflects the electronic temperature - a characteristic fingerprint of unbound electron-hole pair recombination. Furthermore, two-pulse excitation correlation measurements were performed to study the dynamics of electronic cooling, which shows two decay time components, one of less than 100 fs and a slower component of few ps associated with the electron-phonon and phonon-lattice bath thermalizations, respectively. Our work may shed light on further studies of the exciton Mott transition into other two-dimensional materials and their heterostructures and its applications in nanolasers and other optoelectronic devices.

Probiotic Lactobacillus rhamnosus EM1107 prevents hyperglycemia, alveolar bone loss, and inflammation in a rat model of diabetes and periodontitis.

BACKGROUND: This study evaluated the antihyperglycemic, anti-bone-resorptive, and anti-inflammatory efficacy of the probiotic Lactobacillus rhamnosus EM1107 in an experimental model of ligature-induced periodontitis in diabetic rats treated with metformin (Met). METHODS: A total of 114 male Wistar rats was randomly divided into six groups: (1) control, (2) experimental periodontitis (EP), (3) EP + diabetes mellitus (DM), (4) EP + probiotic (Prob), (5) EP + DM + Prob, and (6) EP + DM + Prob + Met. The animals received probiotic gavage during the 30 days of the experiment. DM was induced on the 14th day of the experiment with a single injection of streptozotocin into the penile vein, followed by ligature for EP induction and Met gavage on the 19th day and euthanasia on the 30th day. Heart blood, gingival and periodontal tissue, and hemimaxillae were collected. Biomolecular analysis, immunoenzymatic assays, histomorphology, and microtomographic analysis were performed. Data were statistically analyzed (p < 0.05). RESULTS: There was a significant reduction in interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) in the Prob groups (p < 0.05) as well as in blood glucose levels in the Prob and Met groups (p < 0.001). In addition, histomorphological analysis revealed that the Prob groups had a reduction in inflammatory infiltrate. Tartrate-resistant acid phosphatase (TRAP) and microtomographic analyses showed that the EP/DM/Prob/Met group had significantly lower linear and volumetric bone loss than those who had no treatment (p < 0.01). SOD and GPx immunostaining decreased in all groups receiving probiotics. CONCLUSION: The findings suggest the immunoinflammatory efficacy of the probiotic L. rhamnosus EM1107 administered either alone or in association with Met in type 1 DM associated with periodontitis.

Superstructure based on ß-CD self-assembly induced by a small guest molecule.

The size, shape and surface chemistry of nanoparticles play an important role in cellular interaction. Thus, the main objective of the present study was the determination of the ß-cyclodextrin (ß-CD) self-assembly thermodynamic parameters and its structure, aiming to use these assemblies as a possible controlled drug release system. Light scattering measurements led us to obtain the ß-CD's critical aggregation concentration (cac) values, and consequently the thermodynamic parameters of the ß-CD spontaneous self-assembly in aqueous solution: Δ(agg)G(o) = -16.31 kJ mol(-1), Δ(agg)H(o) = -26.48 kJ mol(-1) and TΔ(agg)S(o) = -10.53 kJ mol(-1) at 298.15 K. Size distribution of the self-assembled nanoparticles below and above cac was 1.5 nm and 60-120 nm, respectively. The number of ß-CD molecules per cluster and the second virial coefficient were identified through Debye's plot and molecular dynamic simulations proposed the three-fold assembly for this system below cac. Ampicillin (AMP) was used as a drug model in order to investigate the key role of the guest molecule in the self-assembly process and the ß-CD:AMP supramolecular system was studied in solution, aiming to determine the structure of the supramolecular aggregate. Results obtained in solution indicated that the ß-CD's cac was not affected by adding AMP. Moreover, different complex stoichiometries were identified by nuclear magnetic resonance and isothermal titration calorimetry experiments.

Self-assembled organic-inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles.

Organic-inorganic magnetic hybrid materials (MHMs) combine a nonmagnetic and a magnetic component by means of electrostatic interactions or covalent bonds, and notable features can be achieved. Herein, we describe an application of a self-assembled material based on ferrite associated with ß-cyclodextrin (Fe-Ni/Zn/ßCD) at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn) were used as an adsorbent system for Cr(3+) and Cr(2)O(7) (2-) ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to determine the particle size distribution, morphology and available binding sites on the surface of the materials. Microscopy analysis demonstrated that both ferrites present two different size domains, at the micro- and nanoscale level, with the latter being able to self-assemble into larger particles. Fe-Ni/Zn/ßCD presented smaller particles and a more homogeneous particle size distribution. Higher porosity for this MHM compared to Fe-Ni/Zn was observed by Brunauer-Emmett-Teller isotherms and positron-annihilation-lifetime spectroscopy. Based on the pKa values, potentiometric titrations demonstrated the presence of ßCD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with ßCD assembled structures. Colloidal stability was inferred as a function of time at different pH values, indicating the sedimentation rate as a function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/ßCD, suggesting its better capability to remove ions (cations and anions) from aqueous solutions compared to that of Fe-Ni/Zn.

Electrospun Materials for Biomedical Applications.

Considered a simple and versatile technique, electrospinning has emerged as a technology for developing 3D materials for a wide range of applications [...].

Polymer-hybrid nanosystems for antiviral applications: Current advances.

The emergence of many new viruses in recent times has resulted in a significant scientific challenge for discovering drugs and vaccines that effectively treat and prevent viral diseases. Nanotechnology has opened doors to prevent the spread of several diseases, including those caused by viruses. Polymer-hybrid nanodevices are a class of nanotechnology platforms for biomedical applications that present synergistic properties among their components, with improved performance compared to conventional forms of therapy. Considering the growing interest in this emerging field and the promising technological advantages of polymer-hybrid nanodevices, this work presents the current status of these systems in the context of prevention and treatment of viral diseases. A brief description of the different types of polymer-hybrid nanodevices highlighting some peculiar characteristics such as their composition, biodistribution, delivery of antigens, and overall immune responses in systemic tissues are discussed. Finally, the work presents the future trends for new nanotechnological hybrid materials based on polymers and perspectives for clinical use.

Optimal Parameters of Laser Therapy to Improve Critical Calvarial Defects.

Body bones play diverse pivotal roles, including the protection of vital organs. For instance, the integrative functions of the brain controlling diverse peripheral actions can be affected by a traumatic injury on the calvaria and the reparative process of a large defect is a challenge in the integrative physiology. Therefore, the development of biomaterials and approaches to improve such defects still requires substantial advances. In this regard, the most attractive approaches have been covering the cavity with inorganic bovine bone (IBB) and, more recently, also using low-level laser therapy (LT), but this issue has opened many questions. Here, it was determined the number of LT sessions required to speed up and to intensify the recovery process of two 5-mm-diameter defects promoted in the calvaria of each subgroup of six adult Wistar rats. The quantitative data showed that 30 days post-surgery, the recovery process by using blood clot-filling was not significantly influenced by the number of LT sessions. However, in the IBB-filled defects, the number of LT sessions markedly contributed to the improvement of the reparative process. Compared to the Control group (non-irradiated), the percentage of mineralization (formation of new bone into the cavities) gradually increased 25, 49, and 52% with, respectively, 4, 7, and 11 sessions of LT. In summary, combining the use of IBB with seven sessions of LT seems to be an optimal approach to greatly improve the recovery of calvarial defects. This translational research opens new avenues targeting better conditions of life for those suffering from large bone traumas and in the present field could contribute to preserve the integrative functions of the brain.

Recovery and identification of mature enamel proteins in ancient teeth.

Proteins in mineralized tissues provide a window to the past, and dental enamel is peculiar in being highly resistant to diagenesis and providing information on a very narrow window of time, such as the developing period; however, to date, complete proteins have not been extracted successfully from ancient teeth. In this work we tested the ability of a whole-crown micro-etch technique to obtain enamel protein samples from mature enamel of recently extracted (n = 2) and ancient (n = 2; ad 800 to 1100) third molars. Samples were analyzed using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) mass spectrometry, and the resulting spectra were searched against the Swiss-Prot protein database using the Mascot software for protein identification. In our protocol, the separation of proteins in gel is not necessary. Successful identification of specific enamel proteins was obtained after whole-crown superficial enamel etching with 10% HCl. Most protein fragments recovered from dry teeth and mummy teeth contained amino-terminal amelogenin peptides. Only one peptide specific for the amelogenin X-isoform was identified. In conclusion, the reported techniques allowed the successful recovery of proteins specific to dental enamel from samples obtained in a very conservative manner, which may also be important in forensic and/or archeological science.

Structural and Electronic Characterization of a Photoresponsive Lanthanum(III) Complex Incorporated into Electrospun Fibers for Phosphate Ester Catalysis.

Herein, we present the light-induced synthesis and characterization of a La3+/spiropyran derivative complex (LaMC) and its application as a catalyst when incorporated into electrospun polycaprolactone (PCL) fibers. In addition to experimental methods, computational calculations were also essential to better understand the structure and electronic characteristics of LaMC. The LaMC complex was identified as a 10-coordinated structure with the La3+ ion coordinated by four oxygens from the phenolate and the carbonyl of the carboxyl acid group from both MC ligands and by six oxygens from three nitrate ligands. In addition, LaMC was capable of getting reversibly isomerized by UV or visible light cycling. All PCL fibers were successively obtained, and their morphologies, surface properties, and catalytic behavior were studied. Results showed that PCL/LaMC fibers were capable of catalyzing bis(2,4-dinitrophenyl)phosphate degradation efficiently. Complete hydrolysis was accomplished in only 1.5 days relative to the half-life time of 35 days for the uncatalyzed hydrolysis at pH 8.1 and 25 °C.

Supramolecular self-assembly of cyclodextrin and higher water soluble guest: thermodynamics and topological studies.

The supramolecular interactions between Imipramine hydrochloride (IMI), a tricyclic antidepressant, and beta-cyclodextrin (betaCD) have been investigated by experimental techniques and theoretical calculations. The association between these molecules might be lead to a host/guest compound, in which the physical chemistry properties of the guest molecule, such as high solubility, can be decreased. These new properties acquired by the inclusion phenomena are important to develop a strategy for pharmaceutical formulation. Nuclear magnetic resonance and horizontal attenuated total reflectance provided relevant information on the complex stoichiometries and the sites of interactions between the host and guest molecules. Stoichiometries of 1:2, 1:1, and 2:1 betaCD/IMI have been detected in solution. Self-diffusion coefficient and dynamic light scattering analysis provided information on the self-aggregation of the complex. Also, isothermal titration calorimetry studies indicated the existence of equilibrium between different complexes in solution. In order to determine the preferred arrangement for the inclusion complex formed by the IMI molecule and betaCD, theoretical calculations were performed. Of all proposed supramolecular structures, the 2:1 betaCD/IMI complex was calculated to be the most energetically favorable, in both gas and aqueous phases. The calculations indicated that the intermolecular hydrogen bonds involving the hydroxyl groups of betaCD play a major role in stabilizing the supramolecular 2:1 structure, corroborating experimental findings.