Hope, resilience and subjective happiness among general population of Paraguay in the post COVID-19 pandemic

BACKGROUND

Positive mental health includes not only the absence of mental disorders but also the presence of subjective well-being, good coping strategies for life stress, and strategies for adapting to community life. It is well known that the COVID-19 pandemic has challenged mental health in general population worldwide. However, research has not measured protective factors for mental health in the general population after the declared end of pandemic by the World Health Organization.

METHODS

This observational, cross-sectional study surveyed 591 Paraguayan participants aged ⩾18 years, who were recruited through an online survey. Demographic characteristics, socioeconomic status were collected as well as mental health and validated tools for hope, resilience, subjective happiness were administered.

RESULTS

Of the participants, 81.6% were women, 54% were married or in a relationship and 90.7% reported an university education. The main source of stress was economic issues (30.3%). A total of 22.7% had been previously diagnosed with a mental disorder, 22.2% had consulted a mental health professional and 10.8% had consumed prescription drugs. 42.6% reported flourishing, 36.2% reported moderate and 21.2% reported languishing mental health.

CONCLUSIONS

This large survey has shown that most of participants reported a flourishing mental health with high ratings at hope, resilience, and subjective happiness scales. Also, the main sources of stress were economic issues, not consequently related to the pandemic. This may add evidences to the international debate on the long term effects of the global pandemic and probably suggests that recovery processes have been collectively adopted in Paraguay.

Suicides among Children and Adolescents in Paraguay: An 18-year National Exploratory Study (2004-2022)

BACKGROUND

Suicide and suicide attempts are impacting events for patients and their relatives, and these behaviors are still taboo among adults and may be even more traumatic when involving children and adolescents.

AIM

In this study we aimed to describe suicide rates among children and adolescents in Paraguay over the last decades as well as associated factors such as sociodemographic characteristics and methods used for suicide.

METHODS

This was an observational and exploratory study describing the frequency and characteristics of suicide among children and adolescents in Paraguay between 2004 and 2022. Official records of all deaths by suicide were reviewed, and statistical analyses were performed. In addition, an attempt was made to predict the number of suicides in the next 5 years using a mathematical model based on simple linear regression.

RESULTS

In the 18-year period observed, 940 suicides among children and adolescents were recorded. The mean age was 15.05 ± 1.8 years old. Of these, 51.17% were male, 74.6% were from urban areas, and 22.2% were from the Greater Asunción and Central Department of Paraguay. The most frequently used method of suicide was intentional self-inflicted injury by hanging, strangulation, or suffocation, which all represented 75.3% of the cases. Our mathematical modeling based on simple linear regression determined that the expected yearly number of national suicides in the pediatric population for the following years, from 2023 to 2027, will range between 72 and 81.

CONCLUSION

This study is the first large national epidemiological report on the emerging issue of suicide among children and adolescents in Paraguay. It may be a relevant source of information for mental health professionals, health authorities, and decision makers to develop national prevention strategies and actions against suicide among youths.

The Chikungunya anxiety scale (CHIKAS): Development, validation, and relationship between its items and illness-related factors

Background

Paraguay has recently experienced an exponential increase in chikungunya cases, leading to psychological distress, particularly anxiety.

Aim

To develop and validate the Chikungunya Anxiety Scale (CHIKAS).

Materials and Methods

An initial scale of 18 items was used, which was subjected to validation by expert judgment to obtain 14 items. To determine construct validity, exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) have been employed, and internal and convergent validity were determined. Demographic, socioeconomic, and health status data were also collected.

Results

The study included 974 participants. The final scale consisted of 12 items with evidence of a two-factor model (psychological and physical). The internal validity was good (McDonald's omega = 0.882). The CFA showed good adjustment indices. Regarding participant characteristics, a relationship was found between anxiety due to chikungunya and gender, employment, mental diagnosis, medication use, and chikungunya infection.

Conclusion

The final 12-item CHIKAS had strong psychometric properties and was a two-factor model.

Introducing "MEW2" Software: A Tool to Analyze MQ-NMR Experiments for Elastomers

Low-field time-domain proton Nuclear Magnetic Resonance (NMR) spectroscopy is an attractive and powerful tool for studying the structure and dynamics of elastomers. The existence of crosslinks and other topological constraints in rubber matrices (entanglements and filler-rubber interactions, among others) renders the fast segmental fluctuations of the polymeric chains non-isotropic, obtaining nonzero residual dipolar couplings, which is the main observable of MQ-NMR experiments. A new software, Multiple quantum nuclear magnetic resonance analyzer for Elastomeric Networks v2 (MEW2), provides a new tool to facilitate the study of the molecular structure of elastomeric materials. This program quantitatively analyzes two different sets of experimental data obtained in the same experiment, which are dominated by multiple-quantum coherence and polymer dynamics. The proper quantification of non-coupled network defects (dangling chain ends, loops, etc.) allows the analyzer to normalize the multiple quantum intensity, obtaining a build-up curve that contains the structural information without any influence from the rubber dynamics. Finally, it provides the spatial distribution of crosslinks using a fast Tikhonov regularization process based on a statistical criterion. As a general trend, this study provides an automatic solution to a tedious procedure of analysis, demonstrating a new tool that accelerates the calculations of network structure using 1H MQ-NMR low-field time-domain experiments for elastomeric compounds.

Dermatitis Artefacta: A Practical Guide for Diagnosis and Management

Dermatitis artefacta (DA) is a psycho-dermatologic condition based on patients' behavioral patterns, characterized by an intentional production of cutaneous lesions on their own skin. The clinical presentation can be highly variable. Patients with DA seldom seek psychological support or psychiatric consultation. More often, they seek help from their primary care physician or dermatologist. This review article aims to provide a practical guide for the diagnosis and management of AD and affected patients. A broad literature search was performed using the PubMed and Google Scholar electronic online databases, using key words "dermatitis artefacta", "diagnosis", "management", and "psychodermatology". The search was limited to English and Spanish language articles and was supplemented with themed books and book chapters. DA can occur in a variety of clinical presentations, and physicians should suspect DA in patients with a history of psychiatric disorders or extensive use of healthcare services. The ultimate goal of DA treatment may be a proper referral to mental health services. However, the prognosis is poor even when successful mental health referrals are achieved, with low recovery rates. A useful approach may include the suggestion that a mental health provider can help with the anxiety and the distress generated by the lesions: in this case in this case it will be crucial to discuss this with the mental health provider after obtaining informed consent from the patient. Considering the difficulty in promoting patients' adherence to treatment, the ideal setting for DA treatment is a psycho-dermatologic clinic, where both dermatologic and psychological interventions can be seamlessly integrated.

Wide Excision in Hidradenitis Suppurativa. Does it Modify the Course of Disease

There is a lack of studies assessing whether wide excision surgery in hidradenitis suppurativa affected areas is useful for the global control of the hidradenitis suppurativa. We aimed to find whether surgery results were a better global control on the disease activity in both, the area where the surgery is performed and distant areas. We evaluated the disease course of 17 patients with hidradenitis suppurativa who underwent wide excision of complex fistula tracts between October 2018 and January 2022 at the Hospital Universitario de la Princesa, Madrid. We found that wide excision of complex fistulas produces an overall positive effect on the inflammatory activity in hidradenitis suppurativa that may be important to achieve an adequate control of the disease.

“Pandemic Fatigue” in South America: A Multi-Center Report from Argentina, Bolivia, Paraguay, Peru, and Uruguay

The COVID-19 pandemic has had a heavy impact on daily life, leading to physical and psychosocial consequences. Nowadays, clinicians and health researchers are particularly interested in describing and facing the long-term effects of COVID-19, also known as “long-COVID syndrome”. Pandemic fatigue has been defined as a cluster of demotivation, tiredness, and psychological effects that emerge gradually over time after the infection or through the adoption of the recommended measures to combat it. In this study, we report the findings of a large survey conducted in South America involving 1448 participants (mean age: 33.9 ± 11.2 years old) from Argentina, Bolivia, Uruguay, Peru, and Paraguay. An online survey was launched through the common social media based on a specific assessment aimed to detect the prevalence of pandemic fatigue and associated factors. Socio-demographic characteristics, medical, and personal information were collected; the Pandemic Fatigue Scale (PFS) and the Coronavirus Anxiety Scale (CAS) were also administered. We found mid-levels of pandemic fatigue among respondents (21.7 ± 7.95 score at PFS) as well as significant anxiety related to the COVID-19 pandemic (1.56 ± 2.76 score at CAS). In addition, pandemic fatigue was significantly associated with the experience of the loss of a relative/friend due to COVID-19, anxiety related to the infection, and reliance on social media as a primary source of information on the pandemic. Vaccination significantly reduced the levels of fatigue among respondents. Our findings may add to the international debate regarding the long-term health consequences of the COVID-19 pandemic and strategies to manage them in the general population of South America.

Clinical Significance of Redundant Nerve Roots in Patients with Lumbar Stenosis Undergoing Minimally Invasive Tubular Decompression

OBJECTIVE

Symptomatic lumbar spinal stenosis (LSS) is a common indication for surgery in the elderly. Preoperative radiographic evaluation of patients with LSS often reveals redundant nerve roots (RNRs). The clinical significance of RNRs is uncertain. RNRs have not been studied in the setting of minimally invasive surgery. This study investigates the relationship between RNRs and clinical outcomes after minimally invasive tubular decompression.

METHODS

Chart review was performed for patients with degenerative LSS who underwent minimally invasive decompression. Preoperative magnetic resonance imaging parameters were assessed, and patient-reported outcomes were analyzed.

RESULTS

Fifty-four patients underwent surgery performed at an average of 1.8 ± 0.8 spinal levels. Thirty-one patients (57%) had RNRs. Patients with RNRs were older (median = 72 years vs. 66 years, P = 0.050), had longer median symptom duration (32 months vs. 15 months, P < 0.01), and had more levels operated on (2.1 vs. 1.4; P < 0.01). The median follow-up after surgery was 2 months (range = 1.3-12 months). Preoperative and postoperative patient-reported outcomes were similar based on RNR presence. Patients without RNRs had larger lumbar cross-sectional areas (CSAs) (median = 121 mm² vs. 95 mm², P = 0.014) and the index-level CSA (52 mm² vs. 34 mm², P = 0.007). The CSA was not correlated with RNR morphology or location.

CONCLUSIONS

Preoperative RNRs are associated with increased age, symptom duration, and lumbar stenosis severity. Patients improved after minimally invasive decompression regardless of RNR presence. RNR presence had no effect on short-term clinical outcomes. Further study is required to assess their long-term significance.

Consumo de cannabis y desarrollo de psicosis o esquizofrenia, análisis de la legislación actual y mapeo regional: una revisión sistemática

Introducción: la relación entre el consumo de cannabis y la aparición de síntomas psicóticos está suficientemente fundamentada. La legalización y/o despenalización del cannabis podría aumentar la frecuencia y la cantidad de su consumo entre sus usuarios. Objetivo: esta revisión sistemática pretende resumir los hallazgos de los estudios que investigaron el riesgo, la precocidad y la intensidad de la psicosis en los consumidores de cannabis, teniendo en cuenta el estado de legalización y/o despenalización del consumo de cannabis en diferentes países. Metodología: fueron incluidos artículos publicados hasta mayo de 2018, en lengua inglesa, portuguesa y española, todos extraídos de las bases de datos PubMed y SciELO, respetando los criterios de inclusión y exclusión. Resultados: se incluyeron 19 estudios de 18 países. La relación entre el consumo de cannabis y el inicio de síntomas psicóticos estuvo suficientemente fundamentada. Sin embargo, no hubo datos que respaldaran un aumento en el riesgo, la precocidad o la intensidad de la psicosis en los consumidores de cannabis de países con niveles más altos de legalización/despenalización del uso de cannabis hasta la fecha del presente estudio. Conclusión: el consumo de cannabis está asociado con el desarrollo de psicosis. Hasta el momento, no hay datos que indiquen un aumento en la precocidad, el riesgo o la intensidad de la psicosis en usuarios de cannabis, debido a la legalización o despenalización del uso de cannabis. Sin embargo, la ausencia de datos hasta la fecha no excluye estas posibilidades, ya que ninguno de los estudios analizados en esta revisión evaluó específicamente los efectos de las políticas de legalización/despenalización en esos resultados. Por ello, los estudios prospectivos centrados en los efectos de las políticas de legalización o despenalización deben llevarse a cabo en países como Canadá, España, los Estados Unidos de América (algunos estados), los Países Bajos y Uruguay.

Alopecia areata: A psychodermatological perspective

BACKGROUND

Alopecia Areata (AA) is an autoimmune dermatological disease that could be influenced by psychological factors as part of the pathophysiology of the illness.

AIMS

This review article aims to report on psychodermatological and psychopathological aspects involved in the etiopathogenesis and comorbidities of AA, as well as on the psychiatric and psychological management of affected patients.

METHODS

We conducted a literature search on PubMed and Google Scholar from January 1980 to May 2021 employing the search terms of alopecia areata, psychological factors, psychological impact, psychodermatology, and psychopathology. All lists of references from the identified articles were screened for further relevant studies. The search was limited to English and Spanish language articles and was supplemented with themed books and book chapters. No specific quality criteria were used for the studies selection.

RESULTS

Several authors have found a high comorbidity rate between AA and mental disorders, concluding that stress and psychological factors are involved in both the development and exacerbation of the illness. More evidences are needed in order to describe the associations between the immune response, stress, and the physiological factors observed in AA patients.

CONCLUSION

AA is a complex illness characterized by multifactorial etiology. An interaction between genetic, autoimmune, hormonal, neural, and psychological factors is supposed. Psychopathological aspects of illness need to be better described and considered in the clinical setting.

Preparation of High Molecular Weight Poly(urethane-urea)s Bearing Deactivated Diamines

The synthesis of poly(urethane-urea) (PUUs) bearing deactivated diamines within the backbone polymer chain is presented. Several deactivated diamines present interesting properties for several applications in the biomaterial field due to their attractive biocompatibility. Through an activation with Chloro-(trimethyl)silane (Cl-TMS) during the polymerization reaction, the reactivity of these diamines against diisocyanates was triggered, leading to PUUs with high performance. Indeed, through this activation protocol, the obtained molecular weights and mechanical features increased considerably respect to PUUs prepared following the standard conditions. In addition, to demonstrate the feasibility and versatility of this synthetic approach, diisocyanate with different reactivity were also addressed. The experimental work is supported by calculations of the electronic parameters of diisocyanate and diamines, using quantum mechanical methods.

The Spanish version of the Skin Picking Impact Scale (SPIS) and its Short form (SPIS-S)

Introduction: The Skin Picking Impact Scale (SPIS) is a self-report rating scale that assess the psychosocial impact of excoriation disorder. In this study the SPIS was translated into Spanish and its reliability was measured. Similarly, its short version (SPIS-S) has been translated and tested. Methodology: The recruitment has been performed through a survey launched on social media. All subjects were older than18 years and self-reported being diagnosed with an excoriation disorder. 281 individuals were rated for the validation analysis. SPIS has been translated into Spanish and validated through an. Exploratory and confirmatory factorial analysis. Participants have been also scored with the Skin Picking Scale-Revised (SPS-R). Results: On factor at the exploratory factorial analysis has a raw eigenvalue greater than 1, with 65.5% of total variance. The confirmatory analysis confirmed that the scale is one-dimensional. Cronbach’s alpha also confirmed a good internal consistency (?=0.934 for the SPIS and ?=0.882 for the SPIS-S). Scores between the two scales (SPIS and the SPS-R) have shown a good convergence (r=0.592, p<0.0001). Conclusion: The Spanish version of SPIS and its short version show good psychometric properties and adequately reproduce the one-dimensional model of the original English version.

Sulfur-Modified Carbon Nanotubes for the Development of Advanced Elastomeric Materials

The outstanding properties of carbon nanotubes (CNTs) present some limitations when introduced into rubber matrices, especially when these nano-particles are applied in high-performance tire tread compounds. Their tendency to agglomerate into bundles due to van der Waals interactions, the strong influence of CNT on the vulcanization process, and the adsorptive nature of filler-rubber interactions contribute to increase the energy dissipation phenomena on rubber-CNT compounds. Consequently, their expected performance in terms of rolling resistance is limited. To overcome these three important issues, the CNT have been surface-modified with oxygen-bearing groups and sulfur, resulting in an improvement in the key properties of these rubber compounds for their use in tire tread applications. A deep characterization of these new materials using functionalized CNT as filler was carried out by using a combination of mechanical, equilibrium swelling and low-field NMR experiments. The outcome of this research revealed that the formation of covalent bonds between the rubber matrix and the nano-particles by the introduction of sulfur at the CNT surface has positive effects on the viscoelastic behavior and the network structure of the rubber compounds, by a decrease of both the loss factor at 60 °C (rolling resistance) and the non-elastic defects, while increasing the crosslink density of the new compounds.

ADVANCED CHARACTERIZATION OF RECYCLED RUBBER FROM END-OF-LIFE TIRES

There are currently many well-established applications for recycled rubber from end-of-life tires (ELT), but it is essential to investigate and seek new approaches to enhance the value of these products. Recent developments in new technologies and innovative recycling and devulcanization processes have opened up new perspectives for ELT crumb rubber. To promote the use of these products in newly added value applications, it is essential to develop and optimize methods that allow the characterization of parameters related to the ultimate properties of potential final applications. In this respect, a novel characterization methodology based on advanced 1H double-quantum (DQ) nuclear magnetic resonance experiments has been applied for the first time to quantify the key parameters that characterize the structure of ELT crumb rubber after diverse recycling processes: from simple mechanical grinding to complex devulcanization methods. This experimental approach enables the quantification of parameters that define the network structure of rubber, such as the nonelastic network defects (sol fraction, dangling chain ends, loops), the cross-link density, and the heterogeneity of the network, directly from rubber granulate and powder (without any additional sample preparation steps), overcoming most of the drawbacks and uncertainties that limit the application of traditional rubber characterization methods (e.g., equilibrium swelling experiments). By applying this experimental approach, it is possible to identify and quantify the actual technical limits for a complete selective devulcanization process of ELT crumb rubber.

Design and Synthesis of Bio-Inspired Polyurethane Films with High Performance

In the present work, the synthesis of segmented polyurethanes functionalized with catechol moieties within the hard or the soft segment is presented. For this purpose, a synthetic route of a new catechol diol was designed. The direct insertion of this catechol-free derivative into the rigid phase led to segmented polyurethanes with low performance (σ_max ≈ 4.5 MPa). Nevertheless, when the derivative was formally located within the soft segment, the mechanical properties of the corresponding functionalized polyurethane improved considerably (σ_max ≈ 16.3 MPa), owing to a significant increase in the degree of polymerization. It is proposed that this difference in reactivity could probably be attributed to a hampering effect of this catecholic ring during the polyaddition reaction. To corroborate this hypothesis, a protection of the aromatic ring was carried out, blocking the hampering effect and avoiding secondary reactions. The polyurethane bearing the protected catechol showed the highest molecular weight and the highest stress at break described to date (σ_max ≈ 66.1 MPa) for these kind of catechol-functionalized polyurethanes. Therefore, this new approach allows for the obtention of high-performance polyurethane films and can be applied in different sectors, benefiting from the molecular adhesion introduced by the catechol ring.

Hair-pulling disorder (Trichotillomania): Etiopathogenesis, diagnosis and treatment in a nutshell

Hair-pulling disorder (Trichotillomania) is a disabling mental disorder. Patient's behavior is characterized by the recurrent pulling of own hair with hair loss and a marked dysfunction in various areas of daily life. Trichotillomania is a relatively common disorder with pediatric onset, often associated with significant morbidity, comorbidity, and functional decline. Surprisingly, children or adolescents have been little studied in the research studies on the pathophysiology and psychopathology of trichotillomania. Furthermore, more evidences regarding the effective and evidence-based pharmacological interventions for the treatment of this condition are encouraged. This narrative review will report on the etiopathogenesis and clinical manifestations of trichotillomania including criteria for diagnosis and treatment issues of this complex mental disorder.

A novel strategy to polyurethanes with improved mechanical properties by photoactivation of amidocoumarin moieties

An attractive strategy involving photodimerization of a novel amidocoumarin moiety is presented to prepare polyurethane coatings with excellent mechanical properties. Two families of polyurethanes containing these chromophore units into soft or hard segments were easily synthesized by inserting a small fraction of amidocoumarin-diol (5 wt% or 10 wt%). A systematic study has been carried out comparing hard segment, chromophore content and the influence of this amidocoumarin unit within the hard or soft segment. For all synthetized polymers, mechanical properties of the coatings have been evaluated before and after an excitation of the coumarin units with UV light. The results show that the insertion of coumarin into the hard segment leads to a considerable improvement of the mechanical properties after irradiation. Additionally, the photochemical activity of amidocoumarin was studied by UV-Vis and Raman spectroscopies.

An attractive strategy involving photodimerization of a novel amidocoumarin moiety is presented to prepare polyurethane coatings with excellent mechanical properties.

Structural Characterization of Mono and Dihydroxylated Umbelliferone Derivatives

Coumarin derivatives are a class of compounds with a pronounced wide range of applications, especially in biological activities, in the medicine, pharmacology, cosmetics, coatings and food industry. Their potential applications are highly dependent on the nature of the substituents attached to their nucleus. These substituents modulate their photochemical and photophysical properties, as well as their interactions in their crystalline form, which largely determines the final field of application. Therefore, in this work a series of mono and dihydroxylated coumarin derivatives with different chemical substituents were synthesized and characterized by UV-Visible spectroscopy, thermal analysis (differential scanning calorimetry (DSC) and TGA), ¹H NMR and X-Ray Diffraction to identify limitations and possibilities as a function of the molecular structure for expanding their applications in polymer science.

A spatial ecology study in a high-diversity host community to understand blood-feeding behaviour in Phlebotomus sandfly vectors of Leishmania

Molecular studies indicate that Phlebotomine sandflies (Diptera: Psychodidae) blood feed on many vertebrate species, of which only a few are proven parasite reservoirs. Investigating sandfly vector feeding preferences is therefore important and requires taking into account the availability and accessibility of host species. In terms of the latter, it is necessary to consider the metabolic cost to the insect of reaching the host and moving on to a suitable breeding site. The present study used statistical modelling to compare the feeding patterns of Phlebotomus perniciosus (n = 150), Phlebotomus papatasi (n = 35) and Phlebotomus ariasi (n = 7) on each of an average of 30 host species in a wildlife park in Murcia, Spain. Sandfly feeding movement costs were estimated as a function of the distance and altitude gradients saved by the insect, assuming that they displayed 'site fidelity'. Most (87%) engorged females were caught <100 m from the host on which they had fed. Although the percentage of bloodmeals was highest on fallow deer (Dama dama) (30%) and red deer (Cervus elaphus) (26%), the predicted feeding probability after considering movement cost was highest for red deer and common eland (Taurotragus oryx), and positively associated with host census. These results suggest that, under similar circumstances, sandflies prefer to feed on some host species more than on others.

Psychodermatology of skin picking (excoriation disorder): A comprehensive review

Excoriation disorder (ED) is a primary psychiatric disorder characterized by recurrent skin picking, which may lead to self-induced cutaneous lesions and significant distress or functional impairment. The affected patient is aware of his/her self-destructive behavior but feels unable to give up this habit, despite having made repeated attempts to decrease or stop it. ED is a relatively frequent disorder, of notable heterogeneity and phenomenological complexity, accompanied by significant emotional and physical consequences. Therefore, further research is necessary to enhance the knowledge on its clinical manifestations, epidemiology, and comorbidities. This article presents an update regarding the etiopathogenesis, clinical aspects, and treatment options of ED to provide an up-to-date review for psychiatrists, dermatologists, and general practitioners.

The Effect of Different Oxygen Surface Functionalization of Carbon Nanotubes on the Electrical Resistivity and Strain Sensing Function of Cement Pastes

Different studies in the literature indicate the effectiveness of CNTs as reinforcing materials in cement-matrix composites due to their high mechanical strength. Nevertheless, their incorporation into cement presents some difficulties due to their tendency to agglomerate, yielding a non-homogeneous dispersion in the paste mix that results in a poor cement-CNTs interaction. This makes the surface modification of the CNTs by introducing functional groups on the surface necessary. In this study, three different treatments for incorporating polar oxygen functional groups onto the surface of carbon nanotubes have been carried out, with the objective of evaluating the influence of the type and oxidation degree on the mechanical and electrical properties and in strain-sensing function of cement pastes containing CNTs. One treatment is in liquid phase (surface oxidation with HNO₃/H₂SO₄), the second is in gas phase (O₃ treatment at 25 and 160 °C), and a third is a combination of gas-phase O₃ treatment plus NaOH liquid phase. The electrical conductivity of cement pastes increased with O₃- and O₃-NaOH-treated CNTs with respect to non-treated ones. Furthermore, the oxygen functionalization treatments clearly improve the strain sensing performance of the CNT-cement pastes, particularly in terms of the accuracy of the linear correlation between the resistance and the stress, as well as the increase in the gage factor from 28 to 65. Additionally, the incorporation of either non-functionalized or functionalized CNTs did not produce any significant modification of the mechanical properties of CNTs. Therefore, the functionalization of CNTs favours the de-agglomeration of CNTs in the cement matrix and consequently, the electrical conductivity, without affecting the mechanical behaviour.

Effective Approach toward Conjugated Porous Organic Frameworks Based on Phenanthrene Building Blocks: Metal-Free Heterogeneous Photocatalysts

This paper reports a simple approach for the preparation of new photo-active conjugated porous polymers (CPPs) based on phenanthrene building blocks with a high Brunauer-Emmett-Teller (BET) surface area. Starting from 2,7-diiodophenanthrene-9,10-dione and its bis-dioxolane derivative with different alkynyl comonomers, we prepared a series of CPPs by C-C Sonogashira-Hagihara coupling activated by microwaves. Moreover, we demonstrated that these functionalized CPPs after hydrolysis to the corresponding diketones show much higher BET surface areas than those obtained directly from the phenanthrene-9,10-dione monomer. Reaction of diketone-hydrolyzed polymers with 2,4-difluoro-6-hydroxybenzaldehyde yields phenantroimidazole derivatives. Indeed, these structurally robust polymers result in efficient, recyclable, heterogeneous photo-organocatalysts for the aza-Henry reaction (C-H functionalization) induced by visible-light irradiation.

Coumarins into Polyurethanes for Smart and Functional Materials

Polyurethanes are of undoubted interest for the scientific community and the industry. Their outstanding versatility from tailor-made structures turns them into major polymers for use in a wide range of different applications. As with other polymers, new, emerging molecules and monomers with specific attributes can provide new functions and capabilities to polyurethanes. Natural and synthetic coumarin and its derivatives are characterised by interesting biological, photophysical and photochemical properties. Then, the polyurethanes can exploit those features of many coumarins which are present in their composition to achieve new functions and performances. This article reviews the developments in the proper use of the special properties of coumarins in polyurethanes to produce functional and smart materials that can be suitable for new specific applications.

General approach to prepare polymers bearing pendant isocyanate groups

A versatile synthetic approach for the easy preparation, under smooth reaction conditions, of diverse classes of linear polymers bearing aliphatic or aromatic isocyanate groups in the side chains is described.