Multilayer PVA/gelatin nanofibrous scaffolds incorporated with Tanacetum polycephalum essential oil and amoxicillin for skin tissue engineering application.

Wound infection is still an important challenge in healing of different types of skin injuries. This highlights the need for new and improved antibacterial agents with novel and different mechanisms of action. In this study, by electrospinning process Tanacetum polycephalum essential oil (EO), as a natural antibacterial and anti-inflammatory agent, along with Amoxicillin (AMX) as an antibiotic are incorporated into PVA/gelatin-based nanofiber mats individually and in combination to fabricate a novel wound dressing. Briefly, we fabricated PVA/gelatin loaded by Amoxicillin as first layer for direct contact with wound surface to protects the wound from exogenous bacteria, and then built a PVA/gelatin/Tanacetum polycephalum essential oil layer on the first layer to help cleanses the wound from infection and accelerates wound closure. Finally, PVA/gelatin layer as third layer fabricated on middle layer to guarantee desirable mechanical properties. For each layer, the electrospinning parameters were adjusted to form bead-free fibers. The morphology of fabricated nanofiber scaffolds was characterized by Fourier-transform infrared (FTIR) and scanning electron microscopy (SEM). Microscopic images demonstrated the smooth bead-free microstructures fabrication of every layer of nanofiber with a uniform fiber size of 126.888 to 136.833 nm. While, EO and AMX increased the diameter of nanofibers but there was no change in physical structure of nanofiber. The water contact angle test demonstrated hydrophilicity of nanofibers with 47.35°. Although EO and AMX had little effect on reducing hydrophilicity but nanofibers with contact angle between 51.4° until 65.4° are still hydrophilic. Multilayer nanofibers loaded by EO and AMX killed 99.99 % of both gram-negative and gram-positive bacteria in comparison with control and PVA/gelatin nanofiber. Also, in addition to confirming the non-toxicity of nanofibers, MTT results also showed the acceleration of cell proliferation. In vivo wound evaluation in mouse models showed that designed nanofibrous scaffolds could be an appropriate option for wound treatment due to their positive effect on angiogenesis, collagen deposition, granulation tissue formation, epithelialization, and wound closure.

A rationally designed antimicrobial peptide from structural and functional insights of Clostridioides difficile translation initiation factor 1.

A significant increase of hospital-acquired bacterial infections during the COVID-19 pandemic has become an urgent medical problem. Clostridioides difficile is an urgent antibiotic-resistant bacterial pathogen and a leading causative agent of nosocomial infections. The increasing recurrence of C. difficile infection and antibiotic resistance in C. difficile has led to an unmet need for the discovery of new compounds distinctly different from present antimicrobials, while antimicrobial peptides as promising alternatives to conventional antibiotics have attracted growing interest recently. Protein synthesis is an essential metabolic process in all bacteria and a validated antibiotic target. Initiation factor 1 from C. difficile (Cd-IF1) is the smallest of the three initiation factors that acts to establish the 30S initiation complex to initiate translation during protein biosynthesis. Here, we report the solution nuclear magnetic resonance (NMR) structure of Cd-IF1 which adopts a typical ß-barrel fold and consists of a five-stranded ß-sheet and one short α-helix arranged in the sequential order ß1-ß2-ß3-α1-ß4-ß5. The interaction of Cd-IF1 with the 30S ribosomal subunit was studied by NMR titration for the construction of a structural model of Cd-IF1 binding with the 30S subunit. The short α-helix in IF1 was found to be critical for IF1 ribosomal binding. A peptide derived from this α-helix was tested and displayed a high ability to inhibit the growth of C. difficile and other bacterial strains. These results provide a clue for the rational design of new antimicrobials.IMPORTANCEBacterial infections continue to represent a major worldwide health hazard due to the emergence of drug-resistant strains. Clostridioides difficile is a common nosocomial pathogen and the causative agent in many infections resulting in an increase in morbidity and mortality. Bacterial protein synthesis is an essential metabolic process and an important target for antibiotic development; however, the precise structural mechanism underlying the process in C. difficile remains unknown. This study reports the solution structure of C. difficile translation initiation factor 1 (IF1) and its interaction with the 30S ribosomal subunit. A short α-helix in IF1 structure was identified as critically important for ribosomal binding and function in regulating the translation initiation, which allowed a rational design of a new peptide. The peptide demonstrated a high ability to inhibit bacterial growth with broad-spectrum antibacterial activity. This study provides a new clue for the rational design of new antimicrobials against bacterial infections.

Thermal Transport and Rheological Properties of Hybrid Nanofluids Based on Vegetable Lubricants.

Nanofluids based on vegetal oil with different wt.% of carbon nanotubes (CNT), hexagonal boron nitride (h-BN), and its hybrid (h-BN@CNT) were produced to investigate the effects of these nano-additives on the thermal conductivity and rheological properties of nanofluids. Stable suspensions of these oil/nanostructures were produced without the use of stabilizing agents. The dispersed nanostructures were investigated by SEM, EDS, XRD, and XPS, while the thermal conductivity and rheological characteristics were studied by a transient hot-wire method and steady-state flow tests, respectively. Increases in thermal conductivity of up to 39% were observed for fluids produced with 0.5 wt.% of the hybrid nanomaterials. As for the rheological properties, it was verified that both the base fluid and the h-BN suspensions exhibited Newtonian behavior, while the presence of CNT modified this tendency. This change in behavior is attributed to the hydrophobic character of both CNT and the base oil, while h-BN nanostructures have lip-lip "bonds", giving it a partial ionic character. However, the combination of these nanostructures was fundamental for the synergistic effect on the increase of thermal conductivity with respect to their counterparts.

Development of pullulan/chitosan/salvianolic acid ternary fibrous membranes and their potential for chemotherapeutic applications.

This study investigates the feasibility of centrifugal spinning for producing fibrous membranes containing pullulan, chitosan, and danshen extract. The danshen extract is composed of 20 wt% salvianolic acid B (SA). Citric acid was added to the mixture as a crosslinking agent to promote its use in the aqueous medium. The influence of the danshen concentration (25 wt% and 33 wt%) on fiber morphology, thermal behavior, and the biochemical effect was analyzed. Developed fiber-based membranes consist of long, continuous, and uniform fibers with a sparse scattering of beads. Fiber diameter analysis shows values ranging from 384 ± 123 nm to 644 ± 141 nm depending on the concentration of danshen. The nanofibers show adequate aqueous stability after crosslinking. Thermal analysis results prove that SA is loaded into nanofibers without compromising their structural integrity. Cell-based results indicate that the developed nanofiber membranes promote cell growth and are not detrimental to fibroblast cells. Anticancer studies reveal a promising inhibition to the proliferation of HCT116 colon cancer cells. The developed systems show potential as innovative systems to be used as a bioactive chemotherapeutic drug that could be placed on the removed tumor site to prevent development of colon cancer microdeposits.

Oxymatrine Loaded Cross-Linked PVA Nanofibrous Scaffold: Design and Characterization and Anticancer Properties.

This study focuses on the fabrication, characterization and anticancer properties of biocompatible and biodegradable composite nanofibers consisting of poly(vinyl alcohol) (PVA), oxymatrine (OM), and citric acid (CA) using a facile and high-yield centrifugal spinning process known as Forcespinning. The effects of varying concentrations of OM and CA on fiber diameter and molecular cross-linking are investigated. The morphological and thermo-physical properties, as well as water absorption of the developed nanofiber-based mats are characterized using microscopical analysis, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. In vitro anticancer studies are conducted with HCT116 colorectal cancer cells. Results show a high yield of long fibers embedded with beads. Fiber average diameters range between 462 and 528 nm depending on OM concentration. The thermal analysis results show that the fibers are stable at room temperature. The anticancer study reveals that PVA nanofiber membrane with high concentrations of OM can suppress the proliferation of HCT116 colorectal cancer cells. The study provides a comprehensive investigation of OM embedded into nanosized PVA fibers and the prospective application of these membranes as a drug delivery system.

Glycemic status and health-related quality of life (HRQOL) in populations at risk of diabetes in two Latin American cities.

PURPOSE: To estimate the health-related quality of life (HRQOL) according to glycemic status, and its relationship with sociodemographic and clinical factors in a population at risk of developing type 2 diabetes (T2D). METHODS: Cross-sectional study, using cluster sampling. Data were collected from 1135 participants over 30 years of age, at risk of developing T2D from the PREDICOL project. Participants' glycemic status was defined using an oral glucose tolerance test (OGTT). Participants were divided into normoglycemic subjects (NGT), prediabetes and diabetics do not know they have diabetes (UT2D). HRQOL was assessed using the EQ-5D-3L questionnaire of the EuroQol group. Logistic regression and Tobit models were used to examine factors associated with EQ-5D scores for each glycemic group. RESULTS: The mean age of participants was 55.6 ± 12.1 years, 76.4% were female, and one in four participants had prediabetes or unknown diabetes. Participants reported problems most frequently on the dimensions of Pain/Discomfort and Anxiety/Depression in the different glycemic groups. The mean EQ-5D score in NGT was 0.80 (95% CI 0.79-0.81), in prediabetes, 0.81 (95% CI 0.79-0.83), and in participants with UT2D of 0.79 (95% CI 0.76-0.82), respectively. Female sex, older age, city of residence, lower education, receiving treatment for hypertension, and marital status were significantly associated with lower levels of HRQOL in the Tobit regression analysis. CONCLUSIONS: HRQOL of NGT, prediabetes, and UT2D participants was statistically similar. However, factors such as gender, age. and place of residence were found to be significant predictors of HRQOL for each glycemic group.

Recent Advances in Centrifugal Spinning and Their Applications in Tissue Engineering.

Over the last decade, researchers have investigated the potential of nano and microfiber scaffolds to promote wound healing, tissue regeneration, and skin protection. The centrifugal spinning technique is favored over others due to its relatively straightforward mechanism for producing large quantities of fiber. Many polymeric materials have yet to be investigated in search of those with multifunctional properties that would make them attractive in tissue applications. This literature presents the fundamental process of fiber generation, and the effects of fabrication parameters (machine, solution) on the morphologies such as fiber diameter, distribution, alignment, porous features, and mechanical properties. Additionally, a brief discussion is presented on the underlying physics of beaded morphology and continuous fiber formation. Consequently, the study provides an overview of the current advancements in centrifugally spun polymeric fiber-based materials and their morphological features, performance, and characteristics for tissue engineering applications.

Centrifugally spun poly(D,L-lactic acid)-alginate composite microbeads for drug delivery and tissue engineering.

This work was based on medium-viscosity alginate as a minor constituent in composites with poly lactic acid (PLA) with the objective to prepare compositional variants through Forcespinning® (FS); for future medical applications. Composites within 0.08-0.25 wt% medium-viscosity alginate were used, at fixed PLA, 6.6 wt%, compared with a study using 0.17-0.48 wt% low-viscosity alginate (same PLA), starting from water-in-oil emulsions, before FS. The presence of alginate is proposed here to influence the high surface tension existing at the emulsion water/oil interface, reducing the total energy at this interface, and/or facilitating the particles in the amphiphilic blend to lie-flat (re-orient) for better fit to the PLA curvature. The study revealed a direct correlation of the inner-phase size (alginate/water ratio), to the change in the morphology and structure of the resultant composites before and after FS. The change in the alginate type, revealed characteristics better suited for medical applications by the medium-viscosity alginate. Composites at alginate- medium-viscosity; ≤0.25 wt%, and low-viscosity; ≤0.48 wt%, had fiber networks interwoven with micro-beads, with characteristics better suited for controlled-release drug delivery applications. Alternatively, each alginate type at 1.1 wt%, composites with PLA at 6.6 wt% could bring about homogenous fibrous materials better suited for wound dressing.

Risk of violence from a current or former partner: Associated factors and classification in a nationwide study in Colombia.

Intimate partner violence (IPV) includes assaults that risk a woman's bodily integrity. Intimate partners commit IPV, people with whom the victim shares (or shared) a close personal or sexual relationship. This phenomenon has a great global and national impact. Thus, it is necessary to establish trends of the risk of physical violence to women by their current or former partner in each department of Colombia and its relationship with sociodemographic and health characteristics. This study uses an ecological approach at the departmental level, with victims of intimate partner violence treated at the National Institute of Legal Medicine and Forensic Sciences (INMLyCF). Potential factors were identified through Bayesian factor analysis and were included in the model to estimate risk. The findings show that the Casanare department had the highest risk of producing victims (SMR: 2.545). In departments where the educational level of women is at or below primary school, there is a high-risk ß = 0.343 (0.285, 0.397) of them being assaulted. For the departments in which the employment of women is in sales and services or office workers, the associated factor presents a higher risk ß = 0.361 (0.201, 0.485), as in the risk related to affiliation with the social security system ß = 0.338 (0.246, 0.498), as well as sexual and reproductive life ß = 0.143 (0.003, 0.322). The following categories were associated with physical gender violence: no education and low participation in making purchases at home ß = 0.106 (0.049, 0.199), low participation in decisions about their health, and visits to family and friends ß = 0.240 (0.170, 0.299). Therefore, public health programs should strengthen women's empowerment in household decisions and increase their educational level to reduce this incidence.

Graphene-Coated PVDF/PAni Fiber Mats and Their Applications in Sensing and Nanogeneration.

Forcespinning is a powerful technique to produce fiber systems with suitable properties for a vast array of applications. This study investigates the sensing and energy generation performance of PVDF/PAni fiber mat systems made by the forcespinning method with and without graphene coating. The developed fiber mats were coated with graphene nanoflakes by drop-casting. The graphene-coated nanocomposites show an average output voltage of 75 mV (peak-to-peak), which is 300% higher compared to bare fiber mats, and an output current of 24 mA (peak-to-peak) by gentle finger pressing. Moreover, graphene-coated PVDF/PAni showed a volume conductivity of 1.2 × 10-7 S/cm and was investigated as a promising system for temperature (5 times better sensitivity than normal fiber mat), vibration (2 times better voltage generation), and airflow sensing. The graphene-coated composite has been further investigated as a water tide energy harvesting piezoelectric nanogenerator, with the system generating ∼40 mV for a synthetic ocean wave with a flow rate of 30 mL/min. In the future, graphene-coated nanofiber mats can be a solution for low-powered sensors and to harvest blue energy and vibration energy.

Centrifugally spun alginate-poly(lactic acid) microbeads: A promising carrier for drug delivery and tissue engineering.

A facile and high yield centrifugal spinning technique known as Forcespinning® (FS) was used to develop unique microstructures consisting of PLA microbeads along alginate fibers. Morphological variation and structural features appeared in the field-emission scanning electron micrographs for the PLA-alginate composites and dried PLA-alginate films from precursor emulsions at constant PLA and varied alginate contents. Shrunk and deflated microbeads were observed for composites whilst spherical beads were evident for the PLA control. Furthermore, PLA was found surrounding the alginate when the alginate was present at 0.24 wt% or lower, while alginate (mushroom-like structures), were seen protruding through the PLA layer at ≥0.34 wt% alginate. Rheological characterization of the composite emulsions revealed that the filler (alginate) provided shear thinning properties including pseudoplasticity, desirable for printing and other related applications in contrast to the Newtonian flow shown by the PLA control. Along with infra-red spectroscopy, the nanocomposites were further characterized using thermal gravimetry and differential scanning calorimetry featuring reversible events influenced by heat capacity and irreversible kinetic/thermodynamic counterparts. The work provides a comprehensive investigation of biocompatible networks of PLA-alginate microbeads embedded in nano-sized fibers and the prospective application of these microbeads as a drug delivery system.

Development of zinc oxide/hydroxyapatite/poly(D,L-lactic acid) fibrous scaffold for tissue engineering applications.

Scaffolds based on polymeric fibers represent an engaging biomedical device due to their particular morphology and similarity with extracellular matrices. The biggest challenge to use fibrous materials in the biomedical field is related to their favorable platform for the adhesion of pathogenic microorganisms. Therefore, their optimum performance not only depends on their bioactive potential but also on their antimicrobial properties. The aim of this work was the design of antimicrobial (zinc oxide, ZnO) and bioactive (hydroxyapatite, Hap) fibrous materials using poly(D, L-lactic acid) (PDLLA) as the polymer fiber substrate. Fiber based composite scaffolds were developed using the Forcespinning® technique. For analysis purposes, the morphological, thermal, antimicrobial and biological properties of the fibrous hybrid system obtained at a concentration of 5 wt% of ZnO and 5 wt% of Hap were studied. The incorporation of the aforementioned nanoparticles (NPs) mixture in PDLLA led to an increase in viscosity and a pseudo-plastic tendency of the precursor solution, which caused an increase in fiber diameters and their dispersion of values. Small cavities and certain roughness were the main surface morphology observed on the fibers before and after NPs incorporation. The fiber thermal stability decreased due to the presence of the NPs. The antimicrobial properties of the hybrid fibrous scaffold presented a growth inhibition (GI) of 70 and 85% for E. coli and S. aureus strains, respectively. Concerning the osteoblast-cell compatibility, PDLLA and hybrid PDLLA scaffold showed low toxicity (cell viabilities above 80%), allowing cell growth inside its three-dimension structure and favorable cell morphology extended along the fibers. This behavior suggests a promising potential of this hybrid PDLLA scaffold for bone application.

Predictors of diabetes risk in urban and rural areas in Colombia.

BACKGROUND: Nutritional habits low in fruits and vegetables and sedentary lifestyle are associated with a higher risk of developing Type 2 Diabetes (T2D). However, it is important to assess differences between urban and rural areas. This study aimed to analyze the associations between the risk of developing T2D and setting in the Colombian north coast in 2017. METHODS: This cross-sectional study included 1,005 subjects. Data was collected by interviewing self-identified members of an urban community and a rural-indigenous population. The interaction terms were evaluated as well as the confounders. Then, adjusted binary logistic regressions were used to estimate the odds ratio (OR) and 95% Confidence Intervals (CI). RESULTS: subjects with a high risk of T2D are more likely to belong to the urban setting (OR = 1.908; 95%CI = 1.201-2.01) compared with those with lower T2D after adjusting for age, Body Mass Index (BMI), physical activity, history of high levels of glycemia, and diabetes in relatives. CONCLUSIONS: Urban communities are more likely to have T2D compared with rural-indigenous populations. These populations have differences from the cultural context, including personal, and lifestyle factors.

Validez y confiabilidad del Inventario de orientación suicida ­ ISO-30 en una población colombiana / Validación de la escala de orientación al suicidio ISO-30 / Validity and reliability of the Inventory of suicide orientation ­ ISO-30 in a colombian population

El presente estudio instrumental evaluó las propiedades psicométricas del Inventario de Orientación Suicida ­ ISO-30 con 1922 adolescentes escolarizados de la ciudad de Bogotá. La validez de constructo del inventario se estableció a través de un análisis factorial confirmatorio, utilizándose el método de mínimos cuadrados generalizados (GLS), dando lugar un modelo factorial sustentable, compuesto por cinco factores, igual al inventario original. La confiabilidad del instrumento se estableció, a través del coeficiente Alfa de Cronbach, obteniéndose una confiabilidad excelente (α= .0915) y un coeficiente Omega (Ω=.742). El análisis de reactivos relativo al poder de discriminación del inventario obtuvo un 57% en las correlaciones ítem-escala total con un nivel de discriminación excelente. Se presenta evidencia respecto a la validez y confiabilidad del ISO-30 para evaluar la orientación al suicidio en adolescentes colombianos

The present instrumental study evaluated the psychometric properties of the Inventory of Suicide Orientation - ISO-30 with 1922 school adolescents from Bogotá. The construct validity of the inventory was established through confirmatory factor analysis, using the generalized least squares (GLS) technique, through which a sustainable factorial model was obtained, composed of five factors equal to the original inventory. The reliability of the instrument was established using Cronbach's Alpha coefficient with an excellent result (α= .915) and an omega coefficient (Ω=.742). The analysis of the items, relative to the discrimination power of the items, obtained 57% in item-total scale correlations with an excellent level of discrimination power. These findings prove ISO-30 to be a valid and reliable instrument for evaluating suicide orientation among Colombian adolescents.

Health-related quality of life (HRQoL) in a population at risk of type 2 diabetes: a cross-sectional study in two Latin American cities.

PURPOSE: The purpose of this study was to describe the health-related quality of life (HRQoL) characteristics in a population at risk of developing type 2 diabetes in Barranquilla and Bogotá, Colombia. METHODS: A cross-sectional study with 1135 participants older than 30 years-of-age recruited in Bogotá D.C., and Barranquilla by cluster sampling in 2018 to 2019. The Finnish Diabetes Risk Score (FINDRISC) was used to detect participants at risk of developing type 2 diabetes (T2D). HRQoL was assessed using the EQ-5D-3L questionnaire. Unadjusted and adjusted logistic regression models were used to calculate odds ratios (OR) and their corresponding 95% confidence intervals CI). RESULTS: Moderate or extreme problems appeared more frequently in the dimensions of Pain/Discomfort (60.8%) and Anxiety/Depression (30.8%). The mean score of the EQ-VAS was 74.3 (± 17.3), significantly larger in the state of complete health (11111) compared with those with problems in more than one of the quality-of-life dimensions. Being female and living in Bogota D.C., were associated with greater odds of reporting problems in the Pain (OR 1.6; 95% CI 1.2-2.2) and Discomfort dimensions (OR 1.6; 95% CI 1.2-2.0) respectively and Anxiety/Depression (OR 1.9; 95% CI 1.3-2.7), (OR 9.1; 95% CI 6.6-12.4), respectively. CONCLUSIONS: As living place and sex were associated with dimensions of Pain/Discomfort and Anxiety/Depression in the HRQoL in people at risk of T2D, greater attention should be paid to these determinants of HRQoL to design and reorient strategies with a territorial and gender perspective to achieve better health outcomes. Diabetes is one of the four non-communicable diseases with increasing prevalence in the world, which has made it a serious public health problem. In Colombia, in 2019 diabetes affected 8.4% of the Colombian adult population and more than one million Colombian adults of this age group have hidden or undetected diabetes. This disease is not only characterized by increased premature mortality, loss of productivity, and economic impact, but it also involves a deterioration in the quality of life of people with diabetes with their respective families. However, very Little is known about health-related quality of life (HRQoL) in a population at risk or with prediabetes. This study has evaluated the quality of life in patients at risk of diabetes and their behavior with some variables as sociodemographic, lifestyle, history, and established their difference in two territories of the Colombian Caribbean. The results of this study indicate that the HRQoL of people at risk of type 2 diabetes is affected by factors such as gender, city, dysglycemia, medication for hypertension and education level. Therefore, greater attention should be paid to these determinants of HRQL to design and implement strategies that reduce this risk of developing type 2 diabetes, prevent prediabetes and improve the quality of life in prediabetic or diabetic patients.

Nanofiber-Based Substrate for a Triboelectric Nanogenerator: High-Performance Flexible Energy Fiber Mats.

Flexible and stretchable triboelectric nanogenerators (TENGs) are the next-generation systems for wearable and portable electronics. In this study, we have demonstrated an all nanofiber-based TENG for energy harvesting and biomechanical sensing applications. The TENG was prepared using the Forcespinning (FS) method to produce poly(vinylidene fluoride) (PVDF) and thermoplastic polyurethane (TPU) nanofiber (NF) membranes. The TPU nanofiber membranes were interfaced with a homogeneously sputtered gold nanofilm. The experimental characterization of the PVDF-TPU/Au NF-TENG revealed that surface interfaced with dispersed gold in a TPU fiber membrane produced a maximum open-circuit voltage of 254 V and a short-circuit current of 86 µA output at a 240 bpm load frequency, which was, respectively, 112 and 87% greater than bare PVDF-TPU NF-based TENG. All systems were composed of an active contact surface area of 3.2 × 2.5 cm2. Furthermore, the TENG was able to light up 75 LEDs (1.5 V of each) by the hand-tapping motion. The resistive load and capacitor test results exemplified a TENG offering a simple and high-performance self-chargeable device. Furthermore, we have tested the TENG's response for biomechanical movements at different frequencies, suggesting the TENG's potential to be also used as a cost-effective self-powered flexible body motion sensor.

Aloe Vera extract-based composite nanofibers for wound dressing applications.

Natural, biocompatible, and biodegradable composite nanofibers made of Aloe vera extract, pullulan, chitosan, and citric acid were successfully produced via Forcespinning® technology. The addition of Aloe vera extract at different weight percent loadings was investigated. The morphology, thermal properties, physical properties, and water absorption of the nanofibers were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The developed nanofiber membranes exhibited good water absorption capabilities, synergistic antibacterial activity against Escherichia coli, and promoted cell attachment and growth. Its porous and high surface area structure make it a potential candidate for wound dressing applications due to its ability to absorb excessive blood and exudates, as well as provide protection from infection while maintaining good thermal stability.

Modeling the Growth and Death of Staphylococcus aureus against Melaleuca armillaris Essential Oil at Different pH Conditions.

Essential oils (EO) are a great antimicrobial resource against bacterial resistance in public health. Math models are useful in describing the growth, survival, and inactivation of microorganisms against antimicrobials. We evaluated the antimicrobial activity of Melaleuca armillaris EO obtained from plants placed in the province of Buenos Aires (Argentina) against Staphylococcus aureus. The minimum inhibitory and bactericidal concentrations were close and decreased, slightly acidifying the medium from pH 7.4 to 6.5 and 5.0. This result was also evidenced by applying a sigmoid model, where the time and EO concentration necessaries to achieve 50% of the maximum effect decreased when the medium was acidified. Moreover, at pH 7.4, applying the Gompertz model, we found that subinhibitory concentrations of EO decreased the growth rate and the maximum population density and increased the latency period concerning the control. Additionally, we established physicochemical parameters for quality control and standardization of M. armillaris EO. Mathematical modeling allowed us to estimate key parameters in the behavior of S. aureus and Melaleuca armillaris EO at different pH. This is interesting in situations where the pH changes are relevant, such as the control of intracellular infections in public health or the development of preservatives for the food industry.

Attitudes and collateral psychological effects of COVID-19 in pregnant women in Colombia.

OBJECTIVE: To assess clinical impact, psychological effects, and knowledge of pregnant women during the COVID-19 outbreak in seven cities in Colombia. Currently, there are uncertainty and concerns about the maternal and fetal consequences of SARS-CoV-2 infection during pregnancy. METHODS: A cross-sectional web survey was carried out including pregnant women in seven cities in Colombia. Women were evaluated during the mitigation phase of the SARS-CoV-2 pandemic between April 13 and May 18, 2020. The questions evaluated demographic, knowledge, psychological symptoms, and attitudes data regarding the COVID-19 pandemic. RESULTS: A total of 1021 patients were invited to participate, obtaining 946 valid surveys for analysis. The rate of psychological consequences of the pandemic was much larger than the number of patients clinically affected by the virus, with 50.4% of the entire cohort reporting symptoms of anxiety, 49.1% insomnia, and 25% reporting depressive symptoms. Poorly informed women were more likely to be younger, affiliated to the subsidized regime, and with lower levels of education. CONCLUSION: The knowledge of pregnant women about SARS-CoV-2 infection is far from reality and this seems to be associated with an indirect effect on the concern and psychological stress of pregnant women in Colombia.