Prolame produces anxiolytic- and antidepressant-like effects in middle-aged female rats with less uterotrophic effects than 17ß-estradiol.

Estrogen hormone replacement therapy (EHRT), improving women's life quality at menopause, reduces anxiety and depression symptoms associated with ovarian hormonal decline. However, its potential adverse effects, like thromboembolism and cancer risk, limit its use. Prolame is a synthetic 17ß-amino estrogen with antithrombotic actions that exerts anxiolytic- and antidepressant-like effects on young adult ovariectomized female rats. It is unknown if prolame's effects may be observed in age and endocrine conditions emulating menopause. This study aimed to identify the antidepressant- and anxiolytic-like effects of prolame and E2 (used as a reference estrogen treatment) in middle-aged female rats coursing with irregular cycles, in two different conditions: ovariectomized or gonadally intact. Results were compared with those from young adult ovariectomized rats. Prolame (60 or 120 µg/kg), 17ß-estradiol (E2, 40 or 80 µg/kg), or vehicle were chronically administered, and their effects were evaluated in the elevated plus-maze, defensive burying behavior test, open field test, and forced swimming test. Uterotrophic actions were estimated by uterine weight related to body weight. Prolame and E2 produced robust anxiolytic- and antidepressant-like effects in young adult ovariectomized rats, but these effects were absent in gonadally intact middle-aged rats. Interestingly, only prolame induced anxiolytic- and antidepressant-like effects in middle-aged ovariectomized rats. Uterotrophic effects of prolame were weaker than E2 effects, notably in middle-aged females. Altogether, present data support the notion that prolame has the potential to be considered an EHRT with relevant psychoactive actions and with apparently lower adverse-side effects, especially in middle-aged populations.

Perception of military specialists on physical preparation in the armed forces / Percepción de los especialistas militares sobre la preparación física en las fuerzas armadas

This work analyzes the perception of military specialists in Physical Education on how physical preparation is implemented and could be optimized in the Armed Forces. It is a quantitative, descriptive study (N = 227) having created an ad hoc questionnaire to collect these perceptions. The results indicate that the facilitators believe that: i. The current physical preparation and its evaluation bear little relation to the possible operational contexts; ii. Health and military instruction are perceived as the main training objectives; iii. The traditional training methodology does not seem to be the most suitable to achieve the operational objectives of the Units; iv. The most relevant physical qualities are swimming skill, strength, and endurance; v. The training contents during the mesocycle are still based mainly on running and calisthenics, performed at a moderate intensity; vi. Specific preparation before, during and after Operations should be increased. (AU)

Este trabajo analiza la percepción de diplomados militares en Educación Física sobre cómo se implementa y podría optimizarse la preparación física en las Fuerzas Armadas. Es un estudio cuantitativo, descriptivo (N = 227) habiéndose creado un cuestionario ad hoc para recoger estas percepciones. Los resultados señalan que los diplomados opinan que: i. La preparación física actual y su evaluación tienen poca relación con los posibles contextos operativos; ii. La salud y la instrucción se perciben como los principales objetivos formativos; iii. La metodología tradicional del entrenamiento no parece ser la más idónea para conseguir los objetivos operativos de las Unidades; iv. Las cualidades físicas consideradas más relevantes son competencia en agua, fuerza y resistencia; v. Los contenidos de entrenamiento durante el mesociclo se siguen basando fundamentalmente en la carrera y la calistenia, realizados a una intensidad moderada; vi. Debe incrementarse la preparación específica antes, durante y después de las Operaciones. (AU)

Condición psicofisiológica en el desempeño de tareas sanitario-militares con mascarilla quirúrgica / Psychophysiological Condition in the Performance of Sanitary-Military Tasks with Surgical Mask

Se ha analizado, mediante un diseño cuasi-experimental con 19 sanitarios (33.7 ± 5.1 años), la importancia de la condición física, cognitiva y el rendimiento al portar un equipo de protección con mascarilla quirúrgica durante situaciones de entrenamiento en contextos significativos de intervención militar. Se midieron la frecuencia cardíaca y su variabilidad, los niveles de glucosa, la termorregulación, la fuerza explosiva y el esfuerzo percibido en tareas de rendimiento motor específicas (tapping test, torniquete, municionamiento), y de rendimiento cognitivo y decisional (triaje). Los resultados indican diferencias significativas (p < 05) en función de la condición física (glucemia y fuerza explosiva), del género (fuerza explosiva y torniquete), del hábito tabáquico (esfuerzo percibido) y del cuerpo de pertenencia (nivel de glucemia) en el grupo de estudio. Como conclusión, se destaca la importancia del entrenamiento físico y psicológico para la mejora de la respuesta operativa en situaciones sanitario-militares que requieren el uso de mascarilla quirúrgica. (AU)

Using a quasi-experimental design with 19 health workers (33.7 ± 5.1 years), the importance of physical and cognitive condition and performance when wearing protective equipment with a surgical mask during training situations in significant contexts of military intervention has been analysed. Heart rate and its variability, glucose levels, thermoregulation, explosive strength and perceived effort in specific motor performance tasks (tapping test, tourniquet, ammunition), and cognitive and decisional performance (triage) were measured. The results indicate significant differences (p < 05) depending on the physical condition (blood glucose and explosive strength), gender (explosive strength and tourniquet), smoking habit (perceived effort) and specialty (glucose level) in the study group. In conclusion, the importance of physical and psychological training is highlighted to improve the operational response in health-military situations that require the use of a surgical mask. (AU)

Characterization of the hierarchical architecture and micromechanical properties of walnut shell (Juglans regia L.).

In the present work a comprehensive characterization of the hierarchical architecture of the walnut shell (Juglans regia L.) was carried out using scanning electron microscopy (SEM), atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). Furthermore, micromechanical properties (hardness, HIT and elastic modulus, EIT) of plant tissues were evaluated at cell wall level by applying the instrumented indentation technique (IIT). The complex architecture of the material was described in terms of four hierarchical levels (HL): endocarp (H1), plant tissues (H2), plant cells (H3) and cell wall (H4). Our findings revealed that the walnut shell consists of a multilayer structure (sclerenchyma tissue, ST; interface tissue, IT; porous tissue, PT; and flattened parenchyma tissue, FPT), where differences in the microstructure and composition of plant tissues generate parallel gradients along the cross-section. The indentation tests showed a functional gradient with a sandwich-like configuration, i.e., a lightweight and soft layer (PT, HIT = 0.04 GPa) is located between two dense and hard layers (ST, HIT = 0.33 GPa; FPT, HIT = 0.28 GPa); where additionally there is an interface between ST and PT (IT, HIT = 0.16 GPa). This configuration is a successful strategy designed by nature to improve the protection of the kernel by increasing the strength of the shell. Therefore, the walnut shell can be considered as a functionally graded material (FGM), which can be used as bioinspiration for the design of new functional synthetic materials. In addition, we proposed some structure-property-function relationships in the whole walnut shell and in each of the plant tissues.

Effect of pepper extracts on the viability kinetics, topography and Quantitative NanoMechanics (QNM) of Campylobacter jejuni evaluated with AFM.

Campylobacter jejuni is a pathogen bacterium that causes foodborne gastroenteritis in humans. However, phenolic compounds extracted from natural sources such as capsicum pepper plant (Capsicum annuum L. var. aviculare) could inhibit the growth of C. jejuni. Therefore, different extracts were prepared using ultrasonic extraction (USE), conventional extraction (CE) and thermosonic extraction (TSE). C. jejuni was then exposed to chili extracts to examine the antimicrobial effect and their growth/death bacterial kinetics were studied using different mathematical models. Atomic force microscopy was applied to investigate the microstructural and nanomechanical changes in the bacteria. Extracts obtained by TSE had the highest phenolic content (4.59 ± 0.03 mg/g of chili fresh weight [FW]) in comparison to USE (4.12 ± 0.05 mg/g of chili FW) and CE (4.28 ± 0.07 mg/g of chili FW). The inactivation of C. jejuni was more efficient when thermosonic extract was used. The Gompertz model was the most suitable mathematical model to describe the inactivation kinetics of C. jejuni. Roughness and nanomechanical analysis performed by atomic force microscopy (AFM) provided evidence that the chili extracts had significant effects on morphology, surface, and the reduced Young's modulus of C. jejuni. The novelty of this work was integrating growth/death bacterial kinetics of C. jejuni using different mathematical models and chili extracts, and its relationship with the morphological, topographic and nanomechanical changes estimated by AFM.

Effect of calcium oxalate crystals on the micromechanical properties of sclerenchyma tissue from the pecan nutshell (Carya illinoinensis).

The objective of this study was to evaluate the effect of the presence of calcium oxalate (CaOx) crystals on the micromechanical properties of sclerenchyma tissue from the pecan nutshell (Carya illinoinensis). The microstructure of the cross-section nutshell was examined using light microscopy (LM) and atomic force microscopy (AFM). Using an instrumented indentation system, indentation tests with maximum loads of 500 mN were made on the biological material where the variables studied were the number of crystals present in the evaluated area and the size of individual crystals. Microscopic analysis revealed that the pecan nutshell consists of sclerenchyma tissue with multiple CaOx crystals randomly distributed throughout the material, exhibiting prismatic shapes and various sizes. The results of the indentation tests showed that the examined areas where there were crystals (1, 2 or up to 3) presented values of hardness and elastic modulus significantly higher (P < 0.05) compared to the sclerenchyma (without crystals). Likewise, there were no significant differences (P > 0.05) between the values of the micromechanical properties of the areas evaluated as a function of the number of crystals. On the other hand, it was observed that the size of the crystals did not show a direct correlation with the mechanical properties evaluated as expected. In conclusion, the biomineralization phenomenon is a successful strategy designed by nature to improve the rigidity of the pecan nutshell, where the CaOx crystals strengthen the structure by increasing the micromechanical properties.

Efectividad analgésica del tapentadol en el dolor neuropático secundario al síndrome postlaminectomía / Analgesic effectiveness of tapentadol in neuropathic pain secondary to post-laminectomy syndrome

Objetivo: El objetivo del presente estudio es evaluar la eficacia y seguridad de tapentadol de liberación a 100 o 200 mg vía oral cada 24 horas, de acción prolongada, para el tratamiento del síndrome postlaminectomía (SPL) en una serie de pacientes con dolor neuropático en tratamiento analgésico inefectivo. Material y métodos: Se realizó un estudio unicéntrico, longitudinal, prospectivo y observacional, en el que se reclutaron 30 pacientes a la clínica de dolor de un centro de referencia de tercer nivel que sufrían de SPL y que cumplían con todos los criterios de inclusión; a quienes se les aplicó el cuestionario Brief Pain Inventory en su versión en español y el test de Lanss antes y después de iniciar tratamiento con tapentadol, y se aplicó una t de Student para comparar la efectividad global del tratamiento del dolor neuropático. Resultado: Se analizaron datos de 30 pacientes, de los cuales 19 fueron mujeres (63,3 %) y 11 hombres (36,6 %) con diagnóstico de SPL confirmado y con características de dolor de tipo neuropático, quienes fueron divididos en dos grupos: el primer grupo de 13 pacientes (43,3 %) recibió tapentadol a 100 mg vía oral cada 24 horas y el segundo de 17 pacientes (56,6 %) recibió 200 mg vía oral cada 24 horas por cuatro semanas. Se les dio un seguimiento de 4 semanas y se encontró una disminución estadísticamente significativa (valor de p = 0,05) del dolor neuropático en la consulta subsecuente de la clínica del SPL.(AU)

Objective: The objective of this study is to eva­luate the efficacy and safety of long-acting tapentadol 100 or 200 mg orally every 24 hours for the treatment of Postlaminectomy Syndrome (SPL) in a series of patients with pain neuropathic in ineffective analgesic treatment. Material and methods: A single-center, longitudinal, prospective and observational study was conducted, in which 30 patients were recruited to the pain clinic of a third-level reference center who suffered from SPL and who met all the inclusion criteria; To whom the Brief Pain Inventory questionnaire in its Spanish version and the Lanss Test were applied before and after starting treatment with tapentadol and a student's t was applied to compare the overall effectiveness of the treatment of neuropathic pain. Results: Data from 30 patients were analyzed, of which 19 were women (63.3 %) and 11 were men (36.6 %) with a diagnosis of confirmed SPL and the presentation of neuropathic pain, who were divided into two groups. The first group of 13 patients (43.3 %) received tapentadol at 100 mg orally every 24 hours, and the second group of 17 patients (56.6 %) received 200 mg orally every 24 hours for four weeks. They were followed up for 4 weeks and statistically significant improvement (p value = 0.05) was found in the SPL clinic.(AU)

Image and fractal analysis as a tool for evaluating salinity growth response between two Salicornia europaea populations.

BACKGROUND: This study describes a promising method for understanding how halophytes adapt to extreme saline conditions and to identify populations with greater resistance. Image and colour analyses have the ability to obtain many image parameters and to discriminate between different aspects in plants, which makes them a suitable tool in combination with genetic analysis to study the plants salt tolerance. To the best of our knowledge, there are no publications about the monitoring of halophytic plants by non-destructive methods for identifying the differences between plants that belong to different maternal salinity environments. The aim is to evaluate the ability of image analysis as a non-destructive method and principal component analysis (PCA) to identify the multiple responses of two S. europaea populations, and to determine which population is most affected by different salinity treatments as a preliminary model of selection. RESULTS: Image analysis was beneficial for detecting the phenotypic variability of two S. europaea populations by morphometric and colour parameters, fractal dimension (FD), projected area (A), shoot height (H), number of branches (B), shoot diameter (S) and colour change (ΔE). S was found to strongly positively correlate with both proline content and ΔE, and negatively with chlorophyll content. These results suggest that proline and ΔE are strongly linked to plant succulence, while chlorophyll decreases with increased succulence. The negative correlation between FD and hydrogen peroxide (HP) suggests that when the plant is under salt stress, HP content increases in plants causing a reduction in plant complexity and foliage growth. The PCA results indicate that the greater the stress, the more marked the differences. At 400 mM a shorter distance between the factorial scores was observed. Genetic variability analysis provided evidence of the differences between these populations. CONCLUSIONS: Our non-destructive method is beneficial for evaluating the halophyte development under salt stress. FD, S and ΔE were relevant indicators of plant architecture. PCA provided evidence that anthropogenic saline plants were more tolerant to saline stress. Furthermore, random amplified polymorphic DNA analysis provided a quick method for determining genetic variation patterns between the two populations and provided evidence of genetic differences between them.

Inference on an heteroscedastic Gompertz tumor growth model.

We consider a non homogeneous Gompertz diffusion process whose parameters are modified by generally time-dependent exogenous factors included in the infinitesimal moments. The proposed model is able to describe tumor dynamics under the effect of anti-proliferative and/or cell death-induced therapies. We assume that such therapies can modify also the infinitesimal variance of the diffusion process. An estimation procedure, based on a control group and two treated groups, is proposed to infer the model by estimating the constant parameters and the time-dependent terms. Moreover, several concatenated hypothesis tests are considered in order to confirm or reject the need to include time-dependent functions in the infinitesimal moments. Simulations are provided to evaluate the efficiency of the suggested procedures and to validate the testing hypothesis. Finally, an application to real data is considered.

A solid-state integrated photo-supercapacitor based on ZnO nanorod arrays decorated with Ag2S quantum dots as the photoanode and a PEDOT charge storage counter-electrode.

A planar solid-state photocapacitor with two electrodes has been prepared for the first time using a passivated film of ZnS with Ag2S quantum dots deposited on ZnO nanorods, which were electrochemically grown on ZnO seed layers, as the photoanode. The supercapacitor part is composed of a electrodeposited poly(3,4-ethylene-dioxythiophene) PEDOT film as the counter-electrode and an ionic liquid-based electrolyte between them deposited by the dip coating method. The different nanostructures and electrodes were morphologically and structurally characterized, and the device was electrochemically characterized and could reach a potential of 0.33 V during photocharge and a storage efficiency of 6.83%.

Postharvest biocontrol of Colletotrichum gloeosporioides on mango using the marine bacterium Stenotrophomonas rhizophila and its possible mechanisms of action.

The marine bacterium Stenotrophomonas rhizophila was assessed in vitro and in vivo as biocontrol agent against anthracnose disease of mango fruit caused by Colletotrichum gloeosporioides. The results showed that in vitro inhibition of the colony diameter and spore germination of the phytopathogen was due to the production of VOCs, competition for nutrients, and lytic enzymes. When a concentration of 1 × 108 cells ml-1 of the antagonist bacterium was applied to the fruit, disease incidence was reduced by 95%, and the lesion diameter of anthracnose decreased by 85%, which offered greater protection than the synthetic fungicide. This is the first report of antagonistic mechanisms of the marine bacterium S. rhizophila against anthracnose disease in mango, which in this study was found to be more effective than the synthetic fungicide.

Evaluation of Nanomechanical Properties of Tomato Root by Atomic Force Microscopy.

Here, different tissue surfaces of tomato root were characterized employing atomic force microscopy on day 7 and day 21 of growth through Young's modulus and plasticity index. These parameters provide quantitative information regarding the mechanical behavior of the tomato root under fresh conditions in different locations of the cross-section of root [cell surface of the epidermis, parenchyma (Pa), and vascular bundles (Vb)]. The results show that the mechanical parameters depend on the indented region, tissue type, and growth time. Thereby, the stiffness increases in the cell surface of epidermal tissue with increasing growth time (from 9.19 ± 0.68 to 13.90 ± 1.68 MPa) and the cell surface of Pa tissue displays the opposite behavior (from 1.74 ± 0.49 to 0.48 ± 0.55); the stiffness of cell surfaces of Vb tissue changes from 10.60 ± 0.58 to 6.37 ± 0.53 MPa, all cases showed a statistical difference (p < 0.05). Viscoelastic behavior dominates the mechanical forces in the tomato root. The current study is a contribution to a better understanding of the cell mechanics behavior of different tomato root tissues during growth.

Risk factors associated with the family care of people with serious mental illness.

BACKGROUND: The aim of the present study is to analyse the variables associated with the family care of people diagnosed with serious mental illness. MATERIAL AND METHODS: A cross-sectional study was carried out involving caregivers of people with serious mental illness (SMI) who were known to the mental health services in Valencia (España) and associations for those with SMI. The sample comprised 417 caregivers who completed a sociodemographic questionnaire and the Zarit Burden Interview. Bivariate analyses (t-test, analysis of variance and Pearson correlation) were performed, as was a multiple linear regression model. Values of p < .05 were considered significant. The study was carried out in accordance with the recommendations of the ethics committees of the participating institutions. RESULTS: The statistical analyses showed significant associations between the sociodemographic and clinical variables of the caregivers and patients and the burden felt by caregivers of people with SMI. The importance of both formal and informal social support stands out as a protective factor against the consequences of the illness's impact on the main caregiver. CONCLUSIONS: The role of spaces of mutual support is crucial. The results suggest that family psychoeducational programmes should be created, applied and evaluated in all mental healthcare services so as to reinforce training in mental health matters and provide support and assessment to caregivers in order to ease their burden.

Factores psicosociales, estrés psicológico y burnout en enfermería: un modelo de trayectorias / Psychosocial factors, psychological stress, and burnout in nursing: a model of trajectories / Fatores psicossociais, estresse psicológico e burnout em enfermagem: um modelo de trajetórias

Resumen Introducción: El personal de enfermería se enfrenta cotidianamente a diferentes eventos asociados al estrés, factores psicosociales y otros mecanismos que afectan su salud mental. Objetivo: Evaluar la correlación entre la demanda psicológica, el control laboral, el apoyo social, el estrés psicológico, y las dimensiones del Síndrome de Burnout (ilusión por el trabajo, desgaste psíquico, indolencia y culpa), en un modelo de trayectorias en enfermeras mexicanas. Metodología: Estudio transversal, observacional, analítico, conducido en 357 profesionales de enfermería de Morelos, México, seleccionados por conveniencia. Los datos fueron colectados empleando tres cuestionarios, la Escala de Estrés Percibido, el Cuestionario del Contenido del Trabajo y el Cuestionario para la Evaluación del Síndrome de Quemarse por el Trabajo. Los programas SPSS 19 y LISREL 8.3 fueron empleados para el procesamiento y modelaje de los datos. Resultados: En el modelo de trayectorias, se especificó como variable mediadora de los factores psicosociales y de las dimensiones del Síndrome de Quemarse por el Trabajo (SQT), al estrés psicológico. Los índices de ajuste fueron aceptables. Se encontraron altos niveles de apoyo social, control laboral e ilusión por el trabajo; grados moderados de demanda psicológica y estrés psicológico; y bajos niveles de desgaste psíquico, indolencia y culpa. Conclusión: Implicaciones para la disciplina, se propone implementar estrategias de intervención efectivas para mantener en el personal de enfermería bajos niveles de demandas psicológicas, altos niveles de control laboral, altos niveles de apoyo social, y niveles moderados de estrés, para prevenir, el SQT.

Abstract Introduction: Nurses frequently face different events associated with stress, psychosocial factors, and other issues which have impacts on their mental health. Objective: To assess the correlation between psychological demand, work control, social support, psychological stress, and burnout dimensions (illusion for the activity, psychic wear, indolence, guilt), within a model of trajectories among Mexican nurses. Methodology: This is a transversal, observational, and analytical study conducted on a convenience sample of 357 nursing professionals from the state of Morelos, Mexico. Data were gathered using three questionnaires, the Perceived Stress Scale, the Job Content Questionnaire, y el Maslach Burnout Inventory. SPSS 19 and LISREL 8.3 were used to process and model the data. Results: Psychological Stress was specified as the mediating variable of the psychosocial factors and dimensions of burnout within the model of trajectories. Adjustment indexes were acceptable. High levels of social support, work control, and illusion for the activity were found. Moderate degrees of psychological demand and psychological stress were found. Low levels of psychic wear, indolence, and guilt were found. Conclusion: It is recommended to implement effective intervention strategies to maintain nursing personnel within low levels of psychological demand, high levels of work control, high levels of social support, and moderate levels of stress, all these in order to prevent the Syndrome of Burnout.

Resumo Introdução: O pessoal de enfermagem se enfrenta cotidianamente a diferentes eventos associados ao estresse, fatores psicossociais e outros mecanismos que afetam sua saúde mental. Objetivo: Avaliar a correlação entre a demanda psicológica, o controle laboral, o apoio social, o estresse psicológico, e as dimensões e da Síndrome de Burnout (ilusão pelo trabalho, desgaste psíquico, indolência e culpa), em um modelo de trajetórias em enfermeiras mexicanas. Metodologia: Estudo transversal, observacional, analítico, conduzido em 357 profissionais de enfermagem de Morelos, México, selecionados por conveniência. Os dados foram coletados empregando três questionários, a Escala de Estresse Percebido, o Questionário do Conteúdo do Trabalho e o Questionário para a Avaliação da Síndrome de Burnout no Trabalho. Os programas SPSS 19 e LISREL 8.3 foram empregados para o processamento e modelagem dos dados. Resultados: No modelo de trajetórias, especificou-se como variável mediadora dos fatores psicossociais e das dimensões da Síndrome de Burnout no Trabalho (SQT), ao estresse psicológico. Os índices de ajuste foram aceitáveis. Encontraram-se altos níveis de apoio social, controle laboral e ilusão pelo trabalho; graus moderados de demanda psicológica e estresse psicológico; e baixos níveis de desgaste psíquico, indolência e culpa. Conclusão: Implicações para a disciplina, propõe-se implementar estratégias de intervenção efetivas para manter no pessoal de enfermagem baixos níveis de demandas psicológicas, altos níveis de controle laboral, altos níveis de apoio social, e níveis moderados de estresse, para prevenir, o SQT.

Study of the porosity of calcified chicken eggshell using atomic force microscopy and image processing.

In this work, the porosity of the layers of calcified chicken eggshell (vertical crystal layer VCL, palisade layer PL and mammillary layer ML) was evaluated using atomic force microscopy (AFM) and image processing (IP). AFM topographic images were obtained from different locations for each layer and along the cross-section of calcified eggshell. Roughness parameters, surface area values, pore size and shape, surface porosity, area occupied by pores and pore density were obtained from AFM and IP. It was observed that the thickest layer (PL) exhibited the highest degree of porosity (surface porosity = 2.75 ± 1.68%, pore density = 162 ± 60 pores/µm2) when compared to the other two layers. In general, the pores located in all layers ("bubble pores") had circular shape and similar sizes. Measurements revealed a porosity gradient along the cross-section which varied with position, i.e., increasing surface porosity from the VCL towards the region of the PL closer to the ML, and decreasing surface porosity from this location towards the ML innermost surface. This suggests that the calcified eggshell has a sandwich-like structure where porosity may influence gas exchange and mechanical properties. The combination of AFM with IP presented here provides a simple and precise method to study porosity in calcified chicken eggshell, and this methodology could be used to examine other types of porous biological materials.

A novel, green, low-cost chitosan-starch hydrogel as potential delivery system for plant growth-promoting bacteria.

The study examines the use of macrobeads for the controlled-release of bacteria. Macrobeads were prepared by an easy dripping-technique using 20/80 wt/wt chitosan-starch blends and sodium tripolyphosphate as cross-linking agent. The resulting polymeric matrix was examined by SEM, XRD, TGA, and solid-RMN. The swelling-equilibrium, thermal behaviour, crystallinity, and size of macrobeads were affected by the autoclave-sterilization. The diameter of the sterilized xerogel was c.a. 1.6 mm. The results suggested that ionotropic-gelation and neutralization were the mechanisms underlying hydrogel formation. Plant growth-promoting bacteria (PGPB) were loaded into macrobeads separately or co-inoculated. Bacteria loaded macrobeads were dried and stored. Bacteria survived at least 12 months in orders of 109 CFU of A. brasilense/g and 108 CFU of P. fluorescens/g. Bacterial release in sterile saline solution tended to a super Case-II transport mechanism. Polymeric-matrix release efficiently both PGPB in natural soils, which uncovers their potential for the formulation of novel and improved biofertilizers.

Morphological and micromechanical characterization of calcium oxalate (CaOx) crystals embedded in the pecan nutshell (Carya illinoinensis).

The morphology and micromechanical properties of the mineral crystals embedded in the pecan nutshell (Carya illinoinensis) were characterized. Qualitative and quantitative morphological analyses carried out revealed that the crystals were comprised of calcium oxalate (CaOx) and have a wide range of sizes, with prismatic shapes, distributed heterogeneously in the sclerenchyma tissue. From indentation tests, it was found that CaOx crystals are stiffer structures compared to stone cells (sclerenchyma tissue), showing hardness and elastic modulus values of 0.53 ±â€¯0.19 GPa and 9.4 ±â€¯1.80 GPa, respectively. Additionally, the values of fracture toughness (0.08 ±â€¯0.02 MPa m0.5) and the brittleness index (9336 m-0.5) revealed that these types of structures are extremely brittle. The results obtained suggest that the main function of the CaOx crystals is to provide structural support to tissue. The presented methodology demonstrates the potential of the instrumented indentation technique (IIT) for in situ micromechanical characterization of mineral crystals located in plant tissues.

Structural, mechanical and enzymatic study of pectin and cellulose during mango ripening.

Mango is an important crop worldwide, with a postharvest loss that is huge due to its climacteric behaviour. This study evaluated the softening of Tommy Atkins mangos during the ripening process. Ripening index (RPI) shown a decrease from 9.18 ±â€¯0.14 to 4.75 ±â€¯0.47. The enzymatic activity agreed with physicochemical parameters and with the structural and mechanical changes. Three pectin fractions were isolated from the mango cell wall: water soluble (WSP), chelator soluble (CSP) and diluted alkali soluble (DASP) pectin. The Younǵs modulus (E) of the primary cell wall was evaluated, it decreased from 1.69 ±â€¯1.02 to 0.39 ±â€¯0.16 MPa, which could be attributed to the softening of the fruit. A linear fit correlation between E and RPI was found. X-ray and confocal laser scanning microscopy analysis showed the changes occurred in the mango cell wall structure during maturation. Novelties of current study can be helpful in the use of mango wastes to obtain cellulose.