A methodological approach by capillary electrophoresis coupled to mass spectrometry via electrospray interface for the characterization of short synthetic peptides towards the conception of self-assembled nanotheranostic agents.

Nanostructures formed by the self-assembling peptide building blocks are attractive materials for the design of theranostic objects due to their intrinsic biocompatibility, accessible surface chemistry as well as cavitary morphology. Short peptide synthesis and modification are straightforward and give access to a great diversity of sequences, making them very versatile building blocks allowing for the design of thoroughly controlled self-assembled nanostructures. In this work, we developed a new CE-DAD-ESI-MS method to characterize short synthetic amphiphilic peptides in terms of exact sequence and purity level in the low 0.1 mg.mL-1 range, without sample treatment. This study was conducted using a model sequence, described to have pH sensitive self-assembling property. Peptide samples obtained from different synthesis processes (batch or flow, purified or not) were thus separated by capillary zone electrophoresis (CZE). The associated dual UV and MS detection mode allowed to evidence the exact sequence together with the presence of impurities, identified as truncated or non-deprotected sequences, and to quantify their relative proportion in the peptide mixture. Our results demonstrate that the developed CE-DAD-ESI-MS method could be directly applied to the characterization of crude synthetic peptide products, in parallel with the optimization of peptide synthetic pathway to obtain controlled sequences with high synthetic yield and purity, which is crucial for further design of robust peptide based self-assembled nanoarchitectures.

Neutralizing antibodies from naturally infected individuals against SARS-CoV-2 Gamma and Delta variants in the Paraguayan population.

INTRODUCTION: Severe Acute Respiratory Syndrome-Coronavirus-2 Virus (SARS-CoV-2) is responsible for Coronavirus Disease 2019 (COVID-19). A substantial number of SARS-CoV-2 infection cases have been reported during the pandemic, and vaccination coverage in some regions, particularly in developing countries, remains very low. SARS-CoV-2 variants of concern (VOCs) have also emerged as some of the most pressing public health issues. In this scenario, it is crucial to know whether COVID-19 convalescent antibodies have cross-neutralizing action against VOCs to contribute to the analysis of the future progress of the pandemic. METHODOLOGY: The plasma of individuals infected with SARS-CoV-2 from June to November 2020 in Paraguay (before the first recorded infections associated with VOCs in the country) was selected. Anti-spike antibodies were determined in plasma samples (n = 626) obtained from this convalescent and unvaccinated group. Using a pseudotyped virus neutralization assay, we then investigated the neutralizing response against D614G variant and Gamma, and Delta VOCs. RESULTS: IgG antibodies against spike were detected in 85.6% of convalescent individuals. Samples from individuals previously infected by a non-VOC showed a 6.6- and 8.1-fold reduction in neutralizing capacity to the Gamma and Delta variants, respectively, when compared to the D614G variant. CONCLUSIONS: Our findings show that antibodies generated by non-VOC infection have reduced neutralizing capabilities against Gamma and Delta variants that appeared subsequently and might have implications for immunity strategies.

Rational Understanding of Loading and Release of Doxorubicin by UV-Light- and pH-Responsive Poly(NIPAM-co-SPMA) Micelle-like Aggregates.

A deep understanding of the interactions between micelle-like aggregates and antineoplastic drugs is paramount to control their adequate delivery. Herein, Poly(NIPAM-co-SPMA) copolymer nanocarriers were synthesized according to our previous published methodology, and the loading and release of poorly and highly water-soluble doxorubicin forms (Dox and Dox-HCl, respectively) were evaluated upon UV light irradiation and pH-variation stimuli. Capillary electrophoresis (CE) coupled to a fluorescence detector (LIF) allowed us to specifically characterize these systems and deeply study the loading and release processes. For this purpose, varying concentrations of doxorubicin were tested, and the loading/release rates were indirectly quantified thanks to the "free" doxorubicin concentration in solution. This study highlighted that Dox loading (9.4 µg/mg) was more effective than Dox-HCl loading (5.5 µg/mg). In contrast, 68 and 74% of Dox-HCl were respectively released after 2 min upon pH variation (from 7.4 to 6.0) and combined UV + pH 6.0 stimuli, while only 27% of Dox was invariably released upon application of the same stimuli. These results are coherent with the characteristics of both DoxHCl and Dox: Electrostatic interactions between Dox-HCl and the micelle-membrane structure (NIPAM) seemed predominant, while hydrophobic interactions were expected between Dox and the SP moieties at the inner part of the micelle-like aggregate, leading to different behaviors in both loading and release of the two doxorubicin forms. For doxorubicin loading concentrations higher than 3 µM, the electrophoretic profiles presented an additional peak. Thanks to CE characterizations, this peak was attributed to the formation of a complex formed between the nonaggregated copolymer and the doxorubicin molecules. This report therefore undergoes deep characterization of the dynamic formation of different micelle/drug complexes involved in the global drug-delivery behavior and therefore contributes to the development of more effective stimuli-responsive nanocarriers.

Proteinaceous microstructure in a capillary: a study of non-linear bending dynamics.

The flap of bendable structures under continuous flow impacts a variety of fields, ranging from energy harvesting to active mixing in microfluidic devices. Similar physical principles determine the flapping dynamics in a variety of systems with different sizes, but a thorough investigation of the bending dynamics at the microscale is still lacking. We employ here two-photon laser polymerization to fabricate elongated proteinaceous flexible microstructures directly within a micro-capillary and we characterize their bending dynamics. The elastic properties of the microstructures with different (circular and square) cross-sections are tested by Atomic Force Microscopy and by studying the deflection-flow dependence in microfluidic experiments at intermediate Reynolds numbers (Rey ≲ 150). The retrieved Young's modulus of the fabricated matrix (100 kPa ≤ E ≤ 4 MPa) falls in the range of most typical biological tissues and solely depends on the laser fabrication intensity. The elastic constant of the microstructures falls in the range of 0.8 nN µm-1 ≤ k ≤ 50 nN µm-1, and fully agrees with the macroscopic Euler Bernoulli theory. For soft microstructures (0.8 nN µm-1 ≤ k ≤ 8 nN µm-1) we reveal undamped bending oscillations under continuous microfluidic flow, corresponding to ∼10% of the total structure deflection. This behavior is ascribed to the coupling of the viscoelasticity and non-linear elasticity of the polymer matrix with non-linear dynamics arising from the time-dependent friction coefficient of the bendable microstructures. We envision that similar instabilities may lead to the development of promising energy conversion nanoplatforms.

Melanin concentration maps by label-free super-resolution photo-thermal imaging on melanoma biopsies.

Surgical excision followed by histopathological examination is the gold standard for melanoma screening. However, the color-based inspection of hematoxylin-and-eosin-stained biopsies does not provide a space-resolved quantification of the melanin content in melanocytic lesions. We propose a non-destructive photo-thermal imaging method capable of characterizing the microscopic distribution and absolute concentration of melanin pigments in excised melanoma biopsies. By exploiting the photo-thermal effect primed by melanin absorption of visible laser light we obtain label-free super-resolution far-infrared thermal images of tissue sections where melanin is spatially mapped at sub-diffraction 40-µm resolution. Based on the finite-element simulation of the full 3D heat transfer model, we are able to convert temperature maps into quantitative images of the melanin molar concentration on B16 murine melanoma biopsies, with 4·10-4 M concentration sensitivity. Being readily applicable to human melanoma biopsies in combination with hematoxylin-and-eosin staining, the proposed approach could complement traditional histopathology in the characterization of pigmented lesions ex-vivo.

Quantitative active super-resolution thermal imaging: The melanoma case study.

Super-resolution image acquisition has turned photo-activated far-infrared thermal imaging into a promising tool for the characterization of biological tissues. By the sub-diffraction localization of sparse temperature increments primed by the sample absorption of modulated focused laser light, the distribution of (endogenous or exogenous) photo-thermal biomarkers can be reconstructed at tunable ∼10-50 µm resolution. We focus here on the theoretical modeling of laser-primed temperature variations and provide the guidelines to convert super-resolved temperature-based images into quantitative maps of the absolute molar concentration of photo-thermal probes. We start from camera-based temperature detection via Stefan-Boltzmann's law, and elucidate the interplay of the camera point-spread-function and pixelated sensor size with the excitation beam waist in defining the amplitude of the measured temperature variations. This can be accomplished by the numerical solution of the three-dimensional heat equation in the presence of modulated laser illumination on the sample, which is characterized in terms of thermal diffusivity, conductivity, thickness, and concentration of photo-thermal species. We apply our data-analysis protocol to murine B16 melanoma biopsies, where melanin is mapped and quantified in label-free configuration at sub-diffraction 40 µm resolution. Our results, validated by an unsupervised machine-learning analysis of hematoxylin-and-eosin images of the same sections, suggest potential impact of super-resolved thermography in complementing standard histopathological analyses of melanocytic lesions.

Especies y sensibilidad a antifúngicos de cepas de Candida spp. aisladas de la cavidad bucal de pacientes con VIH de Paraguay

RESUMEN Candida albicans es la levadura más aislada de la cavidad oral de personas con VIH. Sin embargo, el uso de antifúngicos ha incrementado el aislamiento de especies no C. albicans resistentes o con sensibilidad reducida. El objetivo del estudio fue determinar las especies de Candida y la sensibilidad a los antifúngicos de aislamientos de la cavidad bucal de pacientes con VIH, que acudieron al Instituto de Medicina Tropical entre julio a diciembre de 2019. Las levaduras se sembraron en Agar Cromogénico Candida (CONDA®, España) para la identificación presuntiva. Las colonias verdes se identificaron por PCR dúplex y las de coloración distinta o PCR negativa mediante el sistema comercial VITEK®2. La susceptibilidad antifúngica de C. albicans se determinó por VITEK®2, y las no albicans por el método de difusión de discos. De 278 levaduras, C. albicans se aisló en 70,9 %, seguido de C. tropicalis (8,3 %) y C. krusei (5 %). C. albicans presentó 93 % de sensibilidad y 2 % de sensibilidad dosis dependiente al fluconazol; 87 % sensibles y 3 % con sensibilidad intermedia frente a voriconazol; 97, 98 y 100 % sensibilidad a flucitosina, anfotericina B y equinocandinas, respectivamente. C. parapsilosis y C. tropicalis no registraron resistencias a fluconazol y voriconazol. Todos los aislamientos de C. glabrata fueron sensibles dosis dependientes a fluconazol y todos los aislamientos de C. krusei resultaron sensibles a voriconazol. La portación oral de Candida spp. resistentes a azoles podría llevar a fracasos terapéuticos en pacientes con VIH que desarrollen candidiasis orofaríngea.

ABSTRACT Candida albicans is the most isolated yeast from the oral cavity of people with HIV. However, the use of antifungals has increased the isolation of non-C. albicans resistant species or those with reduced sensitivity. The objective of the study was to determine the Candida species and the sensitivity to antifungals of isolates from the oral cavity of patients with HIV who attended the Institute of Tropical Medicine between July and December 2019. The yeasts were plated in Candida Chromogenic Agar (CONDA®, Spain) for presumptive identification. Green colonies were identified by duplex PCR and those with different staining or negative PCR using the commercial VITEK®2 system. The antifungal susceptibility of C. albicans was determined by VITEK®2, and non albicans by the disk diffusion method. Of 278 yeasts, C. albicans was isolated in 70.9 %, followed by C. tropicalis (8.3 %) and C. krusei (5 %). C. albicans presented 93 % sensitivity and 2 % dose-dependent sensitivity to fluconazole; 87 % sensitive and 3 % intermediate sensitivity to voriconazole; 97, 98, and 100 % sensitive to flucytosine, amphotericin B, and echinocandins, respectively. C. parapsilosis and C. tropicalis did not register resistance to fluconazole and voriconazole. All C. glabrata isolates were dose-dependently sensitive to fluconazole and all C. krusei isolates were sensitive to voriconazole. The oral carriage of Candida spp. resistant to azoles may lead to therapeutic failures in HIV patients who develop oropharyngeal candidiasis.

Multiphoton Laser Fabrication of Hybrid Photo-Activable Biomaterials.

The possibility to shape stimulus-responsive optical polymers, especially hydrogels, by means of laser 3D printing and ablation is fostering a new concept of "smart" micro-devices that can be used for imaging, thermal stimulation, energy transducing and sensing. The composition of these polymeric blends is an essential parameter to tune their properties as actuators and/or sensing platforms and to determine the elasto-mechanical characteristics of the printed hydrogel. In light of the increasing demand for micro-devices for nanomedicine and personalized medicine, interest is growing in the combination of composite and hybrid photo-responsive materials and digital micro-/nano-manufacturing. Existing works have exploited multiphoton laser photo-polymerization to obtain fine 3D microstructures in hydrogels in an additive manufacturing approach or exploited laser ablation of preformed hydrogels to carve 3D cavities. Less often, the two approaches have been combined and active nanomaterials have been embedded in the microstructures. The aim of this review is to give a short overview of the most recent and prominent results in the field of multiphoton laser direct writing of biocompatible hydrogels that embed active nanomaterials not interfering with the writing process and endowing the biocompatible microstructures with physically or chemically activable features such as photothermal activity, chemical swelling and chemical sensing.

Synthesis, Characterization and Evaluation of Peptide Nanostructures for Biomedical Applications.

There is a challenging need for the development of new alternative nanostructures that can allow the coupling and/or encapsulation of therapeutic/diagnostic molecules while reducing their toxicity and improving their circulation and in-vivo targeting. Among the new materials using natural building blocks, peptides have attracted significant interest because of their simple structure, relative chemical and physical stability, diversity of sequences and forms, their easy functionalization with (bio)molecules and the possibility of synthesizing them in large quantities. A number of them have the ability to self-assemble into nanotubes, -spheres, -vesicles or -rods under mild conditions, which opens up new applications in biology and nanomedicine due to their intrinsic biocompatibility and biodegradability as well as their surface chemical reactivity via amino- and carboxyl groups. In order to obtain nanostructures suitable for biomedical applications, the structure, size, shape and surface chemistry of these nanoplatforms must be optimized. These properties depend directly on the nature and sequence of the amino acids that constitute them. It is therefore essential to control the order in which the amino acids are introduced during the synthesis of short peptide chains and to evaluate their in-vitro and in-vivo physico-chemical properties before testing them for biomedical applications. This review therefore focuses on the synthesis, functionalization and characterization of peptide sequences that can self-assemble to form nanostructures. The synthesis in batch or with new continuous flow and microflow techniques will be described and compared in terms of amino acids sequence, purification processes, functionalization or encapsulation of targeting ligands, imaging probes as well as therapeutic molecules. Their chemical and biological characterization will be presented to evaluate their purity, toxicity, biocompatibility and biodistribution, and some therapeutic properties in vitro and in vivo. Finally, their main applications in the biomedical field will be presented so as to highlight their importance and advantages over classical nanostructures.

PVA Films with Mixed Silver Nanoparticles and Gold Nanostars for Intrinsic and Photothermal Antibacterial Action.

PVA films with embedded either silver nanoparticles (AgNP), NIR-absorbing photothermal gold nanostars (GNS), or mixed AgNP+GNS were prepared in this research. The optimal conditions to obtain stable AgNP+GNS films with intact, long lasting photothermal GNS were obtained. These require coating of GNS with a thiolated polyethylene glycol (PEG) terminated with a carboxylic acid function, acting as reticulant in the film formation. In the mixed AgNP+GNS films, the total noble metal content is <0.15% w/w and in the Ag films < 0.025% w/w. The slow but prolonged Ag+ release from film-embedded AgNP (8-11% of total Ag released after 24 h, in the mixed films) results in a very strong microbicidal effect against planktonic Escherichia coli and Staphylococcus aureus bacterial strains (the release of Au from films is instead negligible). Beside this intrinsic effect, the mixed films also exert an on-demand, fast hyperthermal bactericidal action, switched on by NIR laser irradiation (800 nm, i.e., inside the biotransparent window) of the localized surface plasmon resonance (LSPR) absorption bands of GNS. Temperature increases of 30 °C are obtained using irradiances as low as 0.27 W/cm2. Moreover, 80-90% death on both strains was observed in bacteria in contact with the GNS-containing films, after 30 min of irradiation. Finally, the biocompatibility of all films was verified on human fibroblasts, finding negligible viability decrease in all cases.

Factores asociados a caídas en el servicio ambulatorio de geriatría de un hospital universitario en Bogotá (Colombia) / Factors Associated with Falls in the Outpatient Geriatric Service of a University Hospital in Bogotá, Colombia / Fatores associados a quedas no serviço ambulatorial de geriatria de um hospital universitário em Bogotá, Colômbia

Resumen Introducción: las caídas en el adulto mayor influyen de manera negativa en su estado funcional y el riesgo de caídas se eleva progresivamente con la edad, por lo que es importante objetivar todos los factores de riesgo de cada paciente. El objetivo fue describir la prevalencia y los factores asociados con caídas en los pacientes del servicio ambulatorio de geriatría del Hospital Universitario San Ignacio en Bogotá (Colombia). Materiales y métodos: se realizó un estudio descriptivo con pacientes valorados en la consulta externa de geriatría del Hospital Universitario San Ignacio desde enero de 2017 hasta diciembre de 2018. Resultados: se incluyeron 233 pacientes, en quienes se documentó una prevalencia de caídas del 44.5 %. En el análisis bivariado, las variables con asociación estadísticamente significativa fueron: la presencia de trastorno neurocognitivo mayor (TNCM) (OR: 2.31; IC 95 %: 1.28-4.18; p: 0.005), el miedo a caer (OR: 2.27; IC 95 %: 1.24-4.18; p: 0.008), un grado de dependencia moderado a total (OR: 1.93; IC 95 %: 1.11-3.35; p: 0.019) y un mal estado nutricional (OR: 1.18; IC 95 %: 1.099-3.18; p: 0.02). No obstante, en el análisis multivariado, las variables que mantuvieron la asociación fueron el TNCM (OR: 2.09; IC 95 %: 1.14-3.86; p: 0.001) y el miedo a caer (OR: 2.27; IC 95 %: 1.19-4.32; p: 0.001). Conclusión: las variables asociadas con caídas en nuestra población se relacionan con lo descrito en la literatura mundial; son necesarias intervenciones para corregir estos factores y evitar caídas, así como diseñar más estudios para detectar otros factores asociados.

Abstract Introduction: Falls in the elderly have a negative impact on functional status and the risk of falls increases progressively with age, so it is important to objectify all the risk factors of each patient. Our objective was to describe the prevalence and factors associated with falls in patients from the geriatric outpatient service of the San Ignacio University Hospital in Bogotá, Colombia. Materials and methods: A descriptive study was carried out with patients assessed in the geriatric outpatient clinic of the San Ignacio University Hospital from January 2017 to December 2018. Results: 233 patients were included, documenting a prevalence of falls of 44.5%. In the bivariate analysis, the variables with a statistically significant association were: the presence of major neurocognitive disorder (MNCD) (OR: 2.31; 95 %> CI: 1.284.18; p: 0.005), fear of falling (OR: 2.27; 95 %> CI: 1.24-4.18; p: 0.008), a moderate to total degree of dependence (OR: 1.93; 95 %> ci 1.11-3.35; p: 0.019) and a poor nutritional status (OR: 1.18; 95 °/o CI: 1.099-3.18; p: 0.02). However, in the multivariate analysis, the variables that maintained the association were MNCD (OR: 2.09; 95 %> CI: 1.14-3.86; p: 0.001) and fear of falling (OR: 2.27; 95 %> CI: 1.19-4.32; p: 0.001). Discussion: The variables associated with falls in our population are related to what is described in the world literature; Interventions are necessary to correct these factors and avoid falls in our population, as well as to design more studies to detect other associated factors.

Resumo Introdução: as quedas em idosos impactam negativamente o estado funcional e o risco de quedas aumentam progressivamente com a idade, por isso é importante objetivar todos os fatores de risco de cada paciente. Nosso objetivo foi descrever a prevalência e os fatores associados às quedas em pacientes do ambulatório de geriatria do Hospital Universitário San Ignacio em Bogotá, Colômbia. Materiais e métodos: foi realizado um estudo descritivo com pacientes avaliados no ambulatório de geriatria do Hospital Universitário San Ignacio no período de janeiro de 2017 a dezembro de 2018. Resultados: foram incluídos 233 pacientes, documentando uma prevalência de quedas de 44,5%. Na análise bivariada, as variáveis com associação estatisticamente significativa foram: presença de trastorno neurocognitivo maior (TNCM) (OR: 2.31; IC 95%: 1,28-4,18; p: 0,005), medo de cair (OR: 2,27; IC 95%: 1,24-4,18; p: 0,008), grau de dependência moderado a total (OR: 1,93; IC 95%: 1,11-3,35; p: 0,019) e estado nutricional ruim (OR: 1,18; IC 95%: 1,099-3,18; p: 0,02); porém, na análise multivariada, as variáveis que mantiveram a associação foram TNCM (OR: 2,09; IC 95%: 1,14-3,86; p: 0,001) e medo de cair (OR: 2,27; IC 95%: 1,19-4,32; p: 0,001). Conclusão: as variáveis associadas às quedas em nossa população estão relacionadas ao que é descrito na literatura mundial; são necessárias intervenções para corrigir esses fatores e evitar quedas em nossa população, bem como desenhar mais estudos para detectar outros fatores associados.

Factores psicológicos en pacientes con síndrome coronario agudo hospitalizados en el servicio de cardiología del Hospital de Clínicas de la Universidad Nacional de Asunción

RESUMEN Introducción: la ansiedad, la depresión y el estrés son factores psicosociales que favorecen el desarrollo del síndrome coronario agudo. Objetivo: analizar la frecuencia de factores de riesgo cardiovascular y de factores psicológicos en los pacientes ingresados por síndrome coronario agudo en el servicio de Cardiología del Hospital de Clínicas, Universidad Nacional de Asunción. Metodología: diseño observacional, descriptivo, de corte transversal, realizado en pacientes internados con síndrome coronario agudo en el Servicio de Cardiología, desde enero a agosto del 2017. Se midieron variables sociodemográficas, antropométricas, factores de riesgo cardiovascular y factores de riesgo psicosociales. Para medir los factores de riesgo psicosociales se utilizaron las escalas de depresión y ansiedad hospitalaria (HADS) de Goldberg. Resultados: se incluyeron en el estudio 62 pacientes, 60% fueron del sexo masculino, 56% se encontraban en el rango etario de 51 a 70 años y 43% eran casados. Los factores de riesgo cardiovasculares más frecuentes presentes en los pacientes fueron: sedentarismo (90,3%), hipertensión arterial (69,4%) y dislipidemias (62,9%). En relación a los factores de riesgo psicológicos, 48,2% presentaron clínica de ansiedad, 39,2% síntomas de ansiedad, 45,1% síntomas de depresión, 24,1% clínica de depresión. Respecto al nivel de estrés: 22,6% nivel bajo, 46,8% nivel medio y 30,6% nivel alto. Conclusión: la mayoría de los pacientes estudiados con síndrome coronario agudo fueron hombres, casados, entre 51 a 70 años. Los factores de riesgo cardiovasculares más frecuentes fueron el sedentarismo, la hipertensión arterial y dislipidemias. La mayoría presentó clínica de ansiedad, síntomas de depresión y nivel medio de estrés.

ABSTRACT Introduction: Anxiety, depression and stress are psychosocial factors that favor the development of acute coronary syndrome. Objective: To analyze the frequency of cardiovascular risk factors and psychological factors in patients admitted for acute coronary syndrome in the Cardiology Service of the "Hospital de Clínicas", National University of Asunción. Methodology: Observational, descriptive, and cross-sectional design study, performed in patients with acute coronary syndrome, hospitalized in the Cardiology Service from January to August 2017. Sociodemographic and anthropometric variables, cardiovascular risk factors and psychosocial factors were measured. The Goldberg Hospital Depression and Anxiety Scales (HADS) was used to measure psychosocial risk factors. Results: 62 patients were included in the study, 60% were male, 56% were in the age range of 51 to 70 years and 43% were married. The most frequent cardiovascular risk factors present in patients with acute coronary syndrome were: sedentary lifestyle (90.3%), hypertension (69.4%), and dyslipidemia (62,9%). In relation to psychological risk factors, 48.2% had anxiety, 39.2% symptoms of anxiety, 45.1% symptoms of depression, and 24.1% had depression. Regarding the level of stress: 22.6% low level of stress, 46.8% medium level of stress and 30.6% high level of stress. Conclusion: most of the patients studied with acute coronary syndrome were men, married, between 51 and 70 years. The most frequent cardiovascular risk factors were sedentary lifestyle, hypertension, and dyslipidemia. The majority presented symptoms of anxiety, symptoms of depression and a medium level of stress.

Photothermally active nanoparticles as a promising tool for eliminating bacteria and biofilms.

Bacterial contamination is a severe issue that affects medical devices, hospital tools and surfaces. When microorganisms adhere to a surface (e.g., medical devices or implants) they can develop into a biofilm, thereby becoming more resistant to conventional biocides and disinfectants. Nanoparticles can be used as an antibacterial agent in medical instruments or as a protective coating in implantable devices. In particular, attention is being drawn to photothermally active nanoparticles that are capable of converting absorbed light into heat. These nanoparticles can efficiently eradicate bacteria and biofilms upon light activation (predominantly near the infrared to near-infrared spectral region) due a rapid and pronounced local temperature increase. By using this approach new, protective, antibacterial surfaces and materials can be developed that can be remotely activated on demand. In this review, we summarize the state-of-the art regarding the application of various photothermally active nanoparticles and their corresponding nanocomposites for the light-triggered eradication of bacteria and biofilms.

Attachment Tendencies, Big 5 Personality Traits, and Self-Efficacy as Predictors of Mentors' Relationships with Aggressive Children.

Youth mentoring is theorized as a relationship-based intervention in which a strong mentor-mentee bond functions as a mediator of positive outcomes. Given evidence for the importance of a positive relationship, the current study investigated whether differences in mentors' self-reported attachment tendencies (avoidance and ambivalence), Big Five personality traits, and self-efficacy predicted match quality after one academic semester. We also tested whether mentors' experience of conflict in the relationship moderated the relation between these characteristics and match quality. Participants were college student mentors (N = 190) paired with elementary school children identified via teacher and peer reports as highly aggressive. Separate regression analyses indicated that avoidance, openness, and self-efficacy significantly predicted mentor-rated (but not child-rated) match quality in expected directions. Moderator analyses revealed a mixed pattern of results: at low levels of conflict, ambivalence was a negative predictor of match quality, whereas extraversion and agreeableness were positive predictors. At high levels of conflict, openness and conscientiousness were positive predictors of match quality, whereas agreeableness was a negative predictor. The findings suggest it is important for mentoring programs to consider mentor characteristics when screening, training, and matching mentors, particularly in relationships with children identified as aggressive.

Nanocomposite Sprayed Films with Photo-Thermal Properties for Remote Bacteria Eradication.

Currently there is a strong demand for novel protective materials with efficient antibacterial properties. Nanocomposite materials loaded with photo-thermally active nanoparticles can offer promising opportunities due to the local increase of temperature upon near-infrared (NIR) light exposure capable of eradicating bacteria. In this work, we fabricated antibacterial films obtained by spraying on glass slides aqueous solutions of polymers, containing highly photo-thermally active gold nanostars (GNS) or Prussian Blue (PB) nanoparticles. Under NIR light irradiation with low intensities (0.35 W/cm2) these films demonstrated a pronounced photo-thermal effect: ΔTmax up to 26.4 °C for the GNS-containing films and ΔTmax up to 45.8 °C for the PB-containing films. In the latter case, such a local temperature increase demonstrated a remarkable effect on a Gram-negative strain (P. aeruginosa) killing (84% of dead bacteria), and a promising effect on a Gram-positive strain (S. aureus) eradication (69% of dead bacteria). The fabricated films are promising prototypes for further development of lightweight surfaces with efficient antibacterial action that can be remotely activated on demand.

Self-Assembled Monolayers of Copper Sulfide Nanoparticles on Glass as Antibacterial Coatings.

We developed an easy and reproducible synthetic method to graft a monolayer of copper sulfide nanoparticles (CuS NP) on glass and exploited their particular antibacterial features. Samples were fully characterized showing a good stability, a neat photo-thermal effect when irradiated in the Near InfraRed (NIR) region (in the so called "biological window"), and the ability to release controlled quantities of copper in water. The desired antibacterial activity is thus based on two different mechanisms: (i) slow and sustained copper release from CuS NP-glass samples, (ii) local temperature increase caused by a photo-thermal effect under NIR laser irradiation of CuS NP-glass samples. This behavior allows promising in vivo applications to be foreseen, ensuring a "static" antibacterial protection tailored to fight bacterial adhesion in the critical timescale of possible infection and biofilm formation. This can be reinforced, when needed, by a photo-thermal action switchable on demand by an NIR light.

Restoration and conservation of anatomic pieces.

In this study, a restoration process was developed with potassium hydroxide (KOH), in order to improve each of the structures for their posterior fixation, through the use of new methods such as the Chilean conservative fixative solution (SFCCh), with exceptional results. Restore anatomical pieces corresponding to corpse and organs, being these last set with the SFCCh. In this work dealt with processes of restoration with potassium hydroxide, sodium chloride, and sodium hypochlorite, the process began with the cleanliness and suture of the structures for subsequent fixing in Chilean conservative fixative solution, making use of a corpse and different anatomical parts. Work based on items found in the database, Elsevier, Science Direct, ProQuest, and MEDLINE. At the end of the process of restoration and conservation of the anatomical pieces, was observed an improvement in muscle pigment with decrease of rigidity in the specimen, additionally a recovery of appearance in the vascular-nervous elements was achieved. The organs were much more malleable and the structures facilitate the identification of specific details, its subsequent immersion in SFCCh allows the longer preservation of the obtained results. The restoration with potassium hydroxide allows the improvement in the appearance of the different anatomical structures and simultaneously to facilitate its study. The SFCCh is an alternative that replaces partially the use of formaldehyde. In addition, it presents toxicity reduction.

Whole-Section Tumor Micro-Architecture Analysis by a Two-Dimensional Phasor-Based Approach Applied to Polarization-Dependent Second Harmonic Imaging.

Second Harmonic Generation (SHG) microscopy has gained much interest in the histopathology field since it allows label-free imaging of tissues simultaneously providing information on their morphology and on the collagen microarchitecture, thereby highlighting the onset of pathologies and diseases. A wide request of image analysis tools is growing, with the aim to increase the reliability of the analysis of the huge amount of acquired data and to assist pathologists in a user-independent way during their diagnosis. In this light, we exploit here a set of phasor-parameters that, coupled to a 2-dimensional phasor-based approach (µMAPPS, Microscopic Multiparametric Analysis by Phasor projection of Polarization-dependent SHG signal) and a clustering algorithm, allow to automatically recover different collagen microarchitectures in the tissues extracellular matrix. The collagen fibrils microscopic parameters (orientation and anisotropy) are analyzed at a mesoscopic level by quantifying their local spatial heterogeneity in histopathology sections (few mm in size) from two cancer xenografts in mice, in order to maximally discriminate different collagen organizations, allowing in this case to identify the tumor area with respect to the surrounding skin tissue. We show that the "fibril entropy" parameter, which describes the tissue order on a selected spatial scale, is the most effective in enlightening the tumor edges, opening the possibility of their automatic segmentation. Our method, therefore, combined with tissue morphology information, has the potential to become a support to standard histopathology in diseases diagnosis.

VEGF (Vascular Endothelial Growth Factor) Functionalized Magnetic Beads in a Microfluidic Device to Improve the Angiogenic Balance in Preeclampsia.

Preeclampsia is a hypertensive pregnancy disease associated with a massive increase in sFlt-1 (soluble form of the vascular endothelial growth factor 1) in the maternal circulation, responsible for angiogenic imbalance and endothelial dysfunction. Pilot studies suggest that extracorporeal apheresis may reduce circulating sFlt-1 and prolong pregnancy. Nonspecific apheresis systems have potential adverse effects because of the capture of many other molecules. Our concept is based on a specific and competitive apheresis approach using VEGF (vascular endothelial growth factor) functionalized magnetic beads to capture sFlt-1 while releasing endogenous PlGF (placental growth factor) to restore a physiological angiogenic balance. Magnetic beads were functionalized with VEGF to capture sFlt-1. Experiments were performed using PBS, conditioned media from human trophoblastic cells, and human plasma. The proof of concept was validated in dynamic conditions in a microfluidic device as an approach mimicking real apheresis. Magnetic beads were functionalized with VEGF and characterized to evaluate their surface ligand density and recognition capabilities. VEGF-coated magnetic beads proved to be an efficient support in capturing sFlt-1 and releasing PlGF. In static conditions, sFlt-1 concentration decreased by 33±13%, whereas PlGF concentration increased by 27±10%. In dynamic conditions, the performances were improved, with 40% reduction of sFlt-1 and up to 2-fold increase of free PlGF. The sFlt-1/PlGF ratio was reduced by 63% in the plasma of preeclamptic patients. Apheresis was also associated with VEGF release. A ligand-based approach using VEGF-coated beads is an effective approach to the capture of sFlt-1 and the release of endogenous PlGF. It offers new perspectives for the treatment of preeclampsia.