Universidad Autónoma de Occidente

Using natural fibers in bio‐based product development offers a promising path toward an environmentally sustainable future. This study aims to characterize natural fibers obtained from food processing companies and artisans across Colombian regions, employing a methodology that can be extended to natural fibers characterization worldwide and supporting research focused on sustainable product development based on natural fibers. The thermal, mechanical, morphological, and surface properties of the fibers were measured using advanced techniques such as dynamic mechanical analysis‐DMA, thermogravimetry‐TGA, computed microtomograph, and 3D‐microscopy. The chemical composition was analyzed using Van Soest methodology and TGA thermogram deconvolution. Thermal characterization reveals that natural fibers start their degradation between 227 and 258°C, defining a safe thermal processing range for natural fiber‐reinforced polymer composites (NFRPC) products. Mechanical properties were measured at temperatures ranging from −50 to 150°C. Among the tested fibers, pineapple leaf fibers, hemp fibers, and toquilla straw exhibited superior mechanical performance up to 100°C suggesting their potential for developing bioproducts across various applications. In contrast, banana and coir coconut fibers showed lower tensile strength and tensile modulus. Surface roughness differs in the longitudinal and transverse directions, suggesting that chambira straw (Ra 0.067 mm), fique fibers (Ra 0.03 mm), and hemp and pineapple leaf fibers (Ra 0.021 mm) may be of interest for further investigation in NFRPC production. This research highlights the progress and challenges in utilizing natural fibers to develop sustainable products. It positively impacts regional economies, drives technological advancements, and expands the potential applications of natural fiber‐reinforced composites. Highlights Novel micro‐CT technique reveals accurate cross‐sectional areas of natural fibers Colombian natural fibers maintain stable tensile properties from −50 to 125°C Toquilla straw shows highest strength‐to‐density ratio among studied fibers Thermal analysis offers rapid verification of natural fiber chemical composition Ashby charts allow comparison of natural fibers and their uses in composites.

Machine learning algorithms have brought remarkable advancements in detecting motion artifacts (MAs) from the photoplethysmogram (PPG) with no measured or synthetic reference data. However, no study has provided a synthesis of these methods, let alone an in-depth discussion to aid in deciding which one is more suitable for a specific purpose. This narrative review examines the application of machine learning techniques for the reference signal-less detection of MAs in PPG signals. We did not consider articles introducing signal filtering or decomposition algorithms without previous identification of corrupted segments. Studies on MA-detecting approaches utilizing multiple channels and additional sensors such as accelerometers were also excluded. Despite its promising results, the literature on this topic shows several limitations and inconsistencies, particularly those regarding the model development and testing process and the measures used by authors to support the method's suitability for real-time applications. Moreover, there is a need for broader exploration and validation across different body parts and a standardized set of experiments specifically designed to test and validate MA detection approaches. It is essential to provide enough elements to enable researchers and developers to objectively assess the reliability and applicability of these methods and, therefore, obtain the most out of them.

We explore the use of fractional controlled-not gates in quantum thermodynamics. The Nth-root gate allows for a paced application of two-qubit operations. We apply it in quantum thermodynamic protocols for charging a quantum battery. Circuits for three (and two) qubits are analysed by considering the generated ergotropy and other measures of performance. We also perform an optimisation of initial system parameters, e.g.,the initial quantum coherence of one of the qubits strongly affects the efficiency of protocols and the system’s performance as a battery. Finally, we briefly discuss the feasibility for an experimental realization.

RATIONALE Limited information exists concerning the causes of recurrent pneumonia in adults, particularly regarding immunodeficiencies or inborn errors of immunity. OBJECTIVES This study aims to evaluate the etiology of recurrent pneumonia in the adult population, with a focus on humoral deficiency and inborn errors of immunity. METHODS A cross-sectional non-interventional study was conducted in Cali, Colombia, from January 2019 to March 2021. Consecutive patients, aged over 14 years but under 65 years, with a history of recurrent pneumonia, were included after providing consent. The study involved a thorough review of their past medical records and radiological studies. All participants underwent complete blood count and serum immunoglobulin level measurements (IgG, IgA, IgM and IgE). Further testing was carried out based on the evaluation of a clinical immunologist. RESULTS Sixty-six (66) individuals, comprising 34 females and 32 males, were enrolled in the study. The onset of symptoms occurred at an average age of 14 years (ranging from 5 to 36 years). The analysis revealed that the most prevalent cause of recurrent pneumonia was inborn errors of immunity (20 cases, 30.3%), followed by idiopathic (9 cases, 13.7%), bronchiectasis (7 cases, 10.7%), primary ciliary dyskinesia (6 cases, 9.0%), asthma (6 cases, 9.0%), and post-tuberculosis complications (5 cases, 7.6%). CONCLUSION Predominantly antibody deficiencies, along with other inborn errors of immunity, were identified as an important factor contributing to recurrent pneumonia in adults. These findings highlight the importance of these conditions as major etiological factors in the context of recurrent pneumonia in the Colombian adult population.

The increasing reliance on fossil fuels and the growing accumulation of organic waste necessitates the exploration of sustainable energy alternatives. Anaerobic digestion (AD) presents one such solution by utilizing secondary biomass to produce biogas while reducing greenhouse gas emissions. Given the crucial role of microbial activity in anaerobic digestion, a deeper understanding of the microbial community is essential for optimizing biogas production. While metagenomics has emerged as a valuable tool for unravelling microbial composition and providing insights into the functional potential in biodigestion, it falls short of interpreting the functional and metabolic interactions, limiting a comprehensive understanding of individual roles in the community. This emphasizes the significance of expanding the scope of metagenomics through innovative tools that highlight the often-overlooked, yet crucial, role of microbiota in biomass digestion. These tools can more accurately elucidate microbial ecological fitness, shared metabolic pathways, and interspecies interactions. By addressing current limitations and integrating metagenomics with other omics approaches, more accurate predictive techniques can be developed, facilitating informed decision-making to optimize AD processes and enhance biogas yields, thereby contributing to a more sustainable future.

Heavy metals are of great environmental and sanitary importance due to the toxicity they generate; therefore, a wide variety of methods for elimination in water has been studied. One of the approaches employed is bioremediation, which involves the use of biomass (microorganisms or plants), living plants (phytoremediation), or biomaterials to eliminate these elements. In this study, we investigated the technical feasibility of using the Trichonephila clavipes spider web as a biomaterial for iron removal from water by bioremediation. A bibliometric analysis was carried out, where the process variables and experimental design were defined using the Response Surface Methodology, and the iron concentrations were measured before and after the experiment using X-ray fluorescence spectroscopy by dispersive energy. The model predicted an iron removal of 91.82% using 28.09 hr, 81.42 ppm of iron, and 0.062 g of spider web, with a relative error of 0.043 of the true value. This work is novel and presents a new methodology for the bioremediation of water contaminated with iron using spider webs. The results indicate a high efficiency in the removal of iron, which could have important implications in solving environmental and health problems associated with the presence of heavy metals in water.

Accurately assessing flap volume and thickness is a crucial aspect of breast reconstruction using the deep inferior epigastric perforator (DIEP) flap, especially in challenging cases such as thin or large-breasted women or bilateral reconstruction. To address this, we present an innovative image processing tool utilizing computed tomography angiography (CTA) to measure DIEP flap volume and thickness. Our approach incorporates an elliptical equation validated on DIEP reconstruction patients. Preoperative abdominal CTA images were obtained from 70 patients who underwent DIEP flap breast reconstruction at Hospital Universitari de Bellvitge from 2017 to 2021. The image processing tool was employed for preoperative quantification, utilizing elliptical approximations, to determine the volume to be harvested and assess the central thickness of the flap. Subsequently, a non-parametric statistical retrospective analysis was conducted to examine these parameters in relation to immediate complications. The mean maximum recruitable volume (MRV) was 1017.15 ± 325.51 cm³, with a mean thickness of 3.65 ± 1.14 cm. No significant correlation was found between postoperative complications and MRV or thickness values. The processing tool offers a reliable solution for accurately measuring the volume and thickness of the DIEP flap from CTA images, aiding surgeons in breast reconstruction decision-making. This innovative approach enhances surgical planning by addressing quantitative values of thickness and volume of the DIEP flap, which is critical for accurate flap assessment.

The article measures the economic effects of decisions made by two agents in the cultural and creative sector. Managers of a cultural event decide to produce it: it mobilizes a flow of artists and creatives who materialize their creations. Individuals decide to visit it: it mobilizes a flow of individuals who produce experiences by attending the event. The result is revealed by the eco- nomic dimension of the value generated by a cultural event: new income and jobs for the host territory of the event and unique and authentic cultural experi- ences for those attending the event. The empirical literature has drawn attention to the need for more precise measures of economic value, in particular that do not overestimate. A combination of instruments is used: interviews (n = 6) with event managers/organizers; a face-to-face survey (n = 173) with represent- atives of commercial stalls; a face-to-face survey of attendees (n = 1,030); and, an input–output model is adapted to the area of impact. The article provides a methodologically useful framework for identifying and estimating more reliable measures of the material (economic) value created by a cultural event, which can be replicated in a variety of events around the world.

Social housing projects trigger significant urban transformations in adjacent urban areas. Global South countries invest considerable resources in new social housing to reduce quantitative housing deficits, but their effects on urban transformations in neighboring areas are often overlooked. Although informal settlements are widespread in Global South cities, few studies focus on their transformations due to new social housing projects. To address this literature gap, we employed a quasiexperimental method in which we compared urban changes in Bogotá’s informal settlements near social housing projects (experimental group) against those outlying new projects (control group). Through georeferencing, satellite imagery, and field visits, we could determine and compare transformations outside and inside informal settlements in the last decade regarding land values, new structures, housing extensions, basic infrastructure, and public space improvements. We observed that informal neighborhoods near social housing experienced larger land value increases, a higher number of new building permits, and basic infrastructure improvements. We concluded that social housing clusters near informal settlements in Bogotá may explain land value increases that encouraged further private and public investment around these areas. Clusters also attract new social housing that reaches informal settlements and produces a phenomenon of informalization of formality.

Coffee production worldwide has grown by almost 200% since 1950 due to increased demand, being the world's most important traded commodity after oil and the second most popular beverage after water, with more than 500 billion cups of coffee consumed annually (Visser and Dlamini in Sustainability 13:6558, 2021). Colombia is the third largest producer and exporter of coffee worldwide (Garcia-Freites et al. in Biomass Bioenerg 140, 2020). Due to its nature, the coffee sector produces a large amount of waste throughout its production chain, with ~ 0.9 kg of accumulated waste per 1 kg of coffee cherries harvested, equivalent to about 4 thousand tons per year for Colombian production (Garcia-Freites et al. in Biomass Bioenerg 140, 2020). Among the variety of remnants or by-products generated are those from plant pruning and coffee processing (Mendoza Martinez in Biomass Bioenergy 120:68–76, 2019, Hejna in Waste Manage 121:296–330, 2021). This diversity of by-products represents a varied source of molecules suitable for utilisation in different industries in a promising way to solve the environmental and economic impacts represented by the disposal of these remnants. This review aims to present the value and utilisation of these by-products in different industries in which several articles published on the subject were compiled and discussed, with utilisation in the food, agriculture, biorefinery and bioplastics industries. Based on the review presented, it is discovered that the by-products of the coffee industry offer many valuable options developed by scientists to generate value in the coffee production chain that contribute to environmental protection with a promising approach in search of a circular economy. Graphical Abstract

This study introduces an innovative approach to the layered model, emphasizing the physical–chemical characterization of miscible liquid systems through ultrasonic techniques, with a specific focus on the water–ethanol system used in pharmaceutical formulations. Traditional characterization methods, while effective, face challenges due to the complex nature of solutions, such as the need for large pressure variations and strict temperature control. The proposed approach integrates partial molar volumes and partial propagation velocity functions into the layered model, enabling a nuanced understanding of miscibility and interactions. Ultrasonic techniques are used to calculate the isentropic compressibility coefficient for each component of the mixture as well as the total value using an additive mixing rule. Unlike conventional methods, this technique uses tabulated and experimental data to estimate the propagation velocity in the mixture, leading to a more precise computation of the isentropic compressibility coefficient. The results indicate a significant improvement in predicting the behavior of the water–ethanol system compared to the classical layered model. The methodology demonstrates the potential to provide new physicochemical insights that can be applied to other miscible systems beyond water–ethanol. This research has implications for improving the efficiency and accuracy of liquid medication formulations in the pharmaceutical industry.

Thermoplastic polyurethane (TPU) doped with multi-walled carbon nanotubes (MWCNTs) at 1, 3, 5, and 7 wt% has been studied. The effect of MWCNTs on thermal, viscoelastic, and electric properties in the TPU matrix was characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and by impedance spectroscopy. The results show that the thermal, electrical, and viscoelastic properties, such as the glass transition temperature, shifted towards high temperatures. The melting temperature decreased, and the conductivity and the storage modulus increased by 61.5% and 58.3%. The previously observed behavior on the films is due to the increase in the mass percentage of carbon nanotubes (CNTs) in the TPU matrix. Also, it can be said that the CNTs were homogeneously dispersed in the TPU matrix, preventing the movement of the polymer chains, and generating channels or connections that increase the conductivity and improve the thermal properties of the material.

Introduction: Numerical modeling of the intervertebral disc (IVD) is challenging due to its complex and heterogeneous structure, requiring careful selection of constitutive models and material properties. A critical aspect of such modeling is the representation of annulus fibers, which significantly impact IVD biomechanics. This study presents a comparative analysis of different methods for fiber reinforcement in the annulus fibrosus of a finite element (FE) model of the human IVD. Methods: We utilized a reconstructed L4-L5 IVD geometry to compare three fiber modeling approaches: the anisotropic Holzapfel-Gasser-Ogden (HGO) model (HGO fiber model) and two sets of structural rebar elements with linear-elastic (linear rebar model) and hyperelastic (nonlinear rebar model) material definitions, respectively. Prior to calibration, we conducted a sensitivity analysis to identify the most important model parameters to be calibrated and improve the efficiency of the calibration. Calibration was performed using a genetic algorithm and in vitro range of motion (RoM) data from a published study with eight specimens tested under four loading scenarios. For validation, intradiscal pressure (IDP) measurements from the same study were used, along with additional RoM data from a separate publication involving five specimens subjected to four different loading conditions. Results: The sensitivity analysis revealed that most parameters, except for the Poisson ratio of the annulus fibers and C01 from the nucleus, significantly affected the RoM and IDP outcomes. Upon calibration, the HGO fiber model demonstrated the highest accuracy (R² = 0.95), followed by the linear (R² = 0.89) and nonlinear rebar models (R² = 0.87). During the validation phase, the HGO fiber model maintained its high accuracy (RoM R² = 0.85; IDP R² = 0.87), while the linear and nonlinear rebar models had lower validation scores (RoM R² = 0.71 and 0.69; IDP R² = 0.86 and 0.8, respectively). Discussion: The results of the study demonstrate a successful calibration process that established good agreement with experimental data. Based on our findings, the HGO fiber model appears to be a more suitable option for accurate IVD FE modeling considering its higher fidelity in simulation results and computational efficiency.

This dataset features 200 sagittal projection images derived from Cone Beam Computed Tomography (CBCT) scans, corrected according to the Natural Head Position (NHP) guidelines proposed by Fredrik Lundström and Anders Lundström. The images originate from orthodontic patients in Cali, Valle del Cauca, Colombia, encompassing both initial phases and ongoing treatments. The dataset is divided into two groups: 100 images from female subjects (CoF) and 100 from male subjects (CoM), facilitating gender-specific studies. The dataset is accompanied by an Excel file ``Data info.xlsx'' that details the rotation angles in the axial (Yaw), coronal (Roll), and sagittal (Pitch) planes, along with the pixel size and image dimensions. This detailed documentation supports the replication of studies and aids in the interpretation of cephalometric analyses. Corrections made to align the images with NHP standards involve adjustments in the three main anatomical planes using points from the frontozygomatic suture (Fz) in the axial and coronal planes, and sella (S) and nasion (N) for the sagittal plane.

Background Carbapenemase-producing Enterobacterales (CPE) represents a significant threat to global health. This study aimed to characterize clinically and molecularly the CPE isolated from rectal swabs of patients in the intensive care units (ICUs) of a tertiary hospital in Cali, Colombia. Methods This was a cross-sectional observational study. Rectal swabs from patients admitted to the ICUs were collected. Bacterial identification and carbapenemase production were determined using phenotypic and molecular methods. Demographic and clinical data were extracted from electronic medical records. Results The study included 223 patients. Thirty-six patients (36/223, 16.14 %) were found to be colonized or infected by CPE. Factors such as prolonged stay in the ICU, previous exposure to carbapenem antibiotics, use of invasive procedures, and admission due to trauma were associated with CPE. Klebsiella pneumoniae (52.5 %) was the most prevalent microorganism, and the dominant carbapenemases identified were KPC (57.8 %) and NDM (37.8 %). Conclusion Distinguishing carbapenemase subtypes can provide crucial insights for controlling dissemination in ICUs in Cali, Colombia.

Random number generation is essential for applications in simulation, numerical analysis, and data encryption. The ubiquitous presence of system-on-chip (SoC) field-programmable gate array (FPGA) embedded devices in critical sectors necessitates robust random number generators (RNGs) that operate within these specialized environments. Traditional RNGs in GNU/Linux systems derive entropy from peripheral hardware events, which are scarce in SoC FPGA platforms lacking standard PC peripherals. Addressing this challenge, this paper proposes a novel random number generator named NDSTRNG that leverages the unique hardware structure of the SoC FPGA and the inherent randomness of GNU/Linux. The proposed generator employs a non-deterministic sampling model to circumvent reliance on various peripherals while ensuring unbiased output via a linear feedback shift register (LFSR)-based post-processing method. We implement this random number generator in SoC FPGA GNU/Linux using minimal FPGA resources and only one Linux task for sampling. NDSTRNG achieved a throughput exceeding 700 Kbps. Moreover, the entropy source of the generator is evaluated using NIST SP 800-90B, while the quality of the generated random numbers is assessed through ENT, NIST SP 800-22, and DIEHARDER. The results confirm that NDSTRNG meets the stringent criteria for both high-quality and high-speed random number generation, making it suitable for deployment in communication, defense, and medical domains where reliable RNGs are indispensable.

Biomaterials, biodevices, and tissue engineering represent the cutting edge of medical science, promising revolutionary solutions to some of humanity’s most pressing health challenges (Figure 1) [...]

Because of the high demand for carbon fiber reinforced polymer (CFRP) materials across all industries, the reuse and/or recycling of these materials (rCFRP) is necessary in order to meet the principles of the circular economy, including recycling and reuse. The objective of this study is to estimate the lifespan of thermoplastic matrix composite materials reinforced with waste materials (CFRP), which undergo only a mechanical cutting process. This estimation is carried out through the thermal decomposition of polymers, including polymer matrix composite materials, which is a complex process due to the numerous reactions involved. Some authors calculate these kinetic parameters using thermogravimetric analysis (TGA) as it is a quick method, and it allows the identification of gases released during decomposition, provided that the equipment is prepared for it. This study includes a comparison between polyamides 11 and 12, as well as between polyamide composite materials with carbon fiber (CF) and polyamides reinforced with CF/epoxy composite material. The latter is treated with plasma to improve adhesion with polyamides. The behavior of weight as a function of temperature was studied at speeds of 3, 6, 10, 13, 17, and 20 °C/min, finding stability of the polyamides up to a temperature of 400 °C, which was consistent with the analysis by mass spectroscopy, where gas evolution is evident after 400 °C. The estimation of the lifespan was carried out using two different methods including the Toop equation and the free kinetics model (MFK). The energy of the decomposition process was determined using the MFK model, which establishes the energy as a function of the degree of conversion. It is estimated that at 5% decomposition, mechanical properties are lost.

Woven flax-carbon hybrid polyamide biocomposites offer a blend of carbon fibers’ mechanical strength and flax’s environmental advantages, potentially developing material applications. This study investigated their thermal behavior, degradation kinetics, and durability to water uptake and relative humidity exposure and compared them with pure flax and carbon composites with the same matrix. The hybrid composite exhibited intermediate water/moisture absorption levels between pure flax and carbon composites, with 7.2% water absorption and 3.5% moisture absorption. It also displayed comparable thermal degradation resistance to the carbon composite, effectively maintaining its weight up to 300 °C. Further analysis revealed that the hybrid composite exhibited a decomposition energy of 268 kJ/mol, slightly lower than the carbon composite’s value of 288.5 kJ/mol, indicating similar thermal stability. Isothermal lifetime estimation, employing the activation energy (Ed) and degree of conversion facilitated by the Model Free Kinetics method, indicated a 41% higher service life of the hybrid laminate at room temperature compared to the carbon laminate. These insights are crucial for understanding the industrial applications of these materials without compromising durability.