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Ericka Albornoz-Palacios,1 Marysela Ladera-Castañeda,2 Gissela Briceño-Vergel,1 Nancy Córdova-Limaylla,1 Rosa Aroste-Andía,3 Emily Hernández-Huamaní,3 Percy Gavilán-Chávez,3 Miriam Castro-Rojas,2 Luis Cervantes-Ganoza,4 César Cayo-Rojas1 1School of Stomatology, Universidad Privada San Juan Bautista, Lima, Peru; 2Faculty of Dentistry and Postgraduate School, Universidad Nacional Federico Villarreal, Lima, Peru; 3School of Stomatology, Universidad Privada San Juan Bautista, Ica, Peru; 4Faculty of Stomatology, Universidad Inca Garcilaso de la Vega, Lima, PeruCorrespondence: César Cayo-Rojas, Av. Jose Antonio Lavalle Avenue 302-304, (Ex Hacienda Villa), Chorrillos, Lima, Peru, Email cesarcayorojas@gmail.comBackground: The pandemic caused by Covid-19 impacted all areas of social, economic and educational activity. When there is a high risk of spreading highly infectious diseases, education is usually the first service to be suspended. The objective was to evaluate the sociodemographic factors associated with the satisfaction level of Peruvian dental students with virtual classes during the Covid-19 pandemic.Methods: This observational, cross-sectional, analytical study evaluated 237 dental students from the capital city and one Peruvian province using a validated 13-item questionnaire to measure the level of satisfaction with virtual classes. Pearson’s chi-square test and a logit model were used to evaluate the associated factors such as age group, sex, marital status, monthly family income, area of residence, place of origin, occupation and computer use, considering a significance level of p< 0.05.Results: Of all students, 50.6%, 40.1% and 9.3% presented a good, average and poor level of satisfaction, respectively, with the virtual classes received. In addition, those with a monthly family income of less than 500 US dollars were 3.15 times more likely to have poor satisfaction compared to those with a monthly family income of more than 1000 US dollars (AOR = 3.15; 95% CI: 1.23– 8.05). The rest of the variables evaluated were not considered influential factors in the levels of satisfaction with the virtual classes received.Conclusión: Of all students, 50.6% and 9.3% reported good and poor satisfaction with virtual classes during the COVID-19 pandemic, respectively. Monthly family income of less than 500 US dollars was an influential factor. In addition, the variables age group, sex, marital status, area of residence, place of origin, occupation and computer use were not found to be influential factors.Keywords: e-learning, online learning, sociodemographic factors, satisfaction level, virtual classrooms, dentistry, Covid − 19

Brigith R Luyo-Peñafiel,1 Gissela Briceño-Vergel,1 Marysela Irene Ladera-Castañeda,2 Nancy Córdova-Limaylla,1 Jose Luis Huamaní-Echaccaya,1 Leysi Romero-Velásquez,1 Emily Hernández-Huamaní,1 Miriam Castro-Rojas,2 Luis Cervantes-Ganoza,3 César Cayo-Rojas1 1School of Stomatology, Universidad Privada San Juan Bautista, Ica, Peru; 2Faculty of Dentistry and Postgraduate School, Research Team “salud Pública – Salud Integral”, Universidad Nacional Federico Villarreal, Lima, Peru; 3Faculty of Stomatology, Universidad Inca Garcilaso de la Vega, Lima, PeruCorrespondence: César Cayo-Rojas, School of Stomatology, Universidad Privada San Juan Bautista, Carretera Panamericana Sur Km. 300, La Angostura, Subtanjalla, Ica, Peru, Email cesarcayorojas@gmail.comBackground: Cleft lip and palate are relatively frequent craniofacial alterations caused by the lack of union of the frontonasal processes with the maxillary processes during the first weeks of intrauterine life. This study evaluated the sociodemographic factors associated with the level of knowledge about management of cleft lip and palate (CLP) patients in Peruvian dental students.Methods: This analytical, observational, cross-sectional and prospective study evaluated 191 dental students belonging to two branches of a private Peruvian university (one branch in the capital city and the other in a province), from September to November 2022. A validated questionnaire of 14 closed multiple-choice questions was used. A logit model was used to evaluate the influence of the variables: sex, age, academic year of study, marital status, relationship with CLP persons, place of origin and area of residence, on the level of knowledge of the students considering a significance level of p< 0.05.Results: Of the total, 77%, 22.5% and 0.5% presented a poor, fair and good level of knowledge, respectively, on the dental management of the patient with cleft lip and palate. In addition, those who lived in urban areas were 2.8 times more likely to have poor knowledge about the dental management of patients with CLP, compared to those who lived in non-urban areas (OR = 2.83; 95% CI: 1.26– 6.33). Finally, sex, age, marital status, place of origin, academic year of studies and relationship with CLP persons were not considered influential factors (p> 0.05).Conclusion: Most of the students showed a poor level of knowledge about the dental management of patients with cleft lip and palate, a risk factor being that the students live in an urban area. It is recommended that educational authorities include selected topics on CLP in subjects related to infant, child and adolescent care.Keywords: cleft lip, cleft palate, associated factors, dentistry, level of knowledge, Peru

Background: The bioeconomy, an evolving concept promoting sustainable use of renewable biological resources, confronts the challenge of balancing growth and sustainability across sectors like biotechnology, agriculture, and forestry. This study aims to elucidate the bioeconomy's dynamic nature, constructing a comprehensive theoretical model addressing these complexities. Methodology: Through an extensive literature review, foundational elements for this model were identified: defining the core concept, delineating relevant variables, specifying assumptions and parameters, and depicting relationships through equations or diagrams. Special attention was given to integrating Georgescu-Roegen's insights, emphasizing causal links, state variables, measurement scales, and validation plans. Results: The model incorporates Georgescu-Roegen's insights, highlighting the importance of clearly defining the bioeconomy for a comprehensive understanding. The proposed model leverages variables, assumptions, and equations within Georgescu-Roegen's framework, serving as a crucial tool for researchers, policymakers, and industry stakeholders. This approach facilitates research structuring, informed decision-making, and interdisciplinary collaboration. Conclusion: By addressing the bioeconomy's evolution, and cross-sectional boundaries, and adopting a broader perspective, this study contributes to policy development for a more sustainable and integrated bioeconomy. Based on empirical knowledge, this model provides not only a solid theoretical framework but also practical guidelines for advancing toward a balanced and resilient bioeconomy. [ABSTRACT FROM AUTHOR]

Special Core Analysis (SCAL) as a tool for characterization of conventional reservoirs in the laboratory reduces the petrophysical uncertainty and optimizes the resolution and precision of rock-fluid petrophysical models to refine reserve estimates, calculate oil in place, and select the best oil-field development mode. Within the SCAL program, measurements of fluid flow capacity through porous media (permeability [Darcy]) are used to characterize geological formations of interest, with the fluctuation of “pressure differential” values being decisive in the calculation of this property. This research focuses on determining the sources that generate these fluctuations and implements a significant reduction by varying certain parameters in the laboratory. Through detailed analysis of the experimental procedure and equipment operation, as well as a statistical analysis, the sources impacting the quality of the measurements were identified. It was found that the precision and accuracy of pressure differential values were considerably low and directly related to: (1) the pressure pulses created in the backpressure system; (2) the high dead volume in the signal conduction lines (piping); and (3) the influence of temperature variation of the measurement environment. Modifications were implemented both in the experimental protocol and the core-flooding equipment, and tests were conducted under the same conditions to observe the changes produced. It was possible to significantly reduce the standard deviation in the measurements of the pressure differential value from 7.08% to 1.45% with respect to the mean. Consequently, these modifications reduced data dispersion, obtaining more-accurate readings of the stability behaviour of the pressure differential value and, thus, generating more-reliable results. The relevance of this work is demonstrated by the improvement in quality and reliability of petrophysical measurements, in addition to the optimization of turnaround times considering that, by reducing dispersion of pressure differentials values, flow stability state in the porous medium is reached in less time, which is a critical condition for permeability evaluations.

The process of fused deposition material (FDM) was used to manufacture propellant grains of Acrylonitrile Butadiene Styrene (ABS) as novel rocket fuel grain, with three types of geometry in the burning port. These solid fuel grains were used to measure the typical characteristics of combustion in rocket motors such as thrust and pressure inside the combustion chamber, seeking to obtain preliminary characteristics of operation and analyze the effect of combustion port geometry on pressure and thrust, using Multivariate Analysis of Variance (MANOVA) as statistical method. Two of the three geometries were manufactured with a helical-finocyl configuration, specially designed to be fabricated by Direct Digital Manufacturing (DDM), the other one was a straight-bore geometry also by DDM. This characterization experiment was performed on a static hybrid rocket engine, designed to inject 99.98% pure nitrous oxide into a combustion chamber with capacity to withstand 6.9 MPa of pressure, with an easy-to-exchange nozzle, avoiding erosive behavior in the throat. Statistical analyses made with the ABS fuel grains, suggest a significant effect on rocket motor pressure and thrust, due to helical geometric changes made to the combustion port of solid fuel grains made by FDM manufacture process.

Bagrada hilaris is a polyphagous herbivore reported as an invasive pest in the United States. During the course of dissecting Burmeister hilaris unique crystals were observed in both the midgut and oviducts. Crystals were identified using X-ray diffraction techniques. Both acicular (i.e., needle-like, slender, and/or tapered) and cubic (i.e., cube shaped) crystals were observed in six of 75 individuals examined (8.0%). The crystals were mainly observed in females (6.7%), followed by males (1.3%) with no crystals observed in the minimal number of nymphs examined (0%). Crystals of both types were detected in the midgut and lateral oviducts of the females and midgut in males. The acicular crystals often appeared as distinct bundles when present in the midgut and oviducts. Crystals varied in size with the acicular crystals ranging from 0.12 mm to 0.5 mm in length although the cubic crystals ranged in length from 0.25 mm to over 1.0 mm with widths of ∼0.25 mm. The cubic crystals were identified as allantoin although the acicular crystals were most likely dl-allantoin in combination with halite. While allantoin in a soluble form is often found in insect tissues and excreta; being present as a crystal, especially in such a large form, is curious and raises some interesting questions. More research is warranted to further understand mechanisms associated with such crystal formation in B. hilaris and can lead to a better understanding of the excretory process in this species and the role allantoin plays in the elimination of excess nitrogen.

Bagrada hilaris is a polyphagous herbivore reported as an invasive pest in the United States. During the course of dissecting Burmeister hilaris unique crystals were observed in both the midgut and oviducts. Crystals were identified using X-ray diffraction techniques. Both acicular (i.e., needle-like, slender, and/or tapered) and cubic (i.e., cube shaped) crystals were observed in six of 75 individuals examined (8.0%). The crystals were mainly observed in females (6.7%), followed by males (1.3%) with no crystals observed in the minimal number of nymphs examined (0%). Crystals of both types were detected in the midgut and lateral oviducts of the females and midgut in males. The acicular crystals often appeared as distinct bundles when present in the midgut and oviducts. Crystals varied in size with the acicular crystals ranging from 0.12 mm to 0.5 mm in length although the cubic crystals ranged in length from 0.25 mm to over 1.0 mm with widths of ∼0.25 mm. The cubic crystals were identified as allantoin although the acicular crystals were most likely dl-allantoin in combination with halite. While allantoin in a soluble form is often found in insect tissues and excreta; being present as a crystal, especially in such a large form, is curious and raises some interesting questions. More research is warranted to further understand mechanisms associated with such crystal formation in B. hilaris and can lead to a better understanding of the excretory process in this species and the role allantoin plays in the elimination of excess nitrogen.

We compared the cost-effectiveness (CE) of an active case-finding (ACF) programme for household contacts of tuberculosis (TB) cases enrolled in first-line treatment to routine passive case-finding (PCF) within an established national TB programme in Peru. Decision analysis was used to model detection of TB in household contacts through: (1) self-report of symptomatic cases for evaluation (PCF), (2) a provider-initiated ACF programme, (3) addition of an Xpert MTB/RIF diagnostic test for a single sputum sample from household contacts, and (4) all strategies combined. CE was calculated as the incremental cost-effectiveness ratio (ICER) in terms of US dollars per disability-adjusted life years (DALYs) averted. Compared to PCF alone, ACF for household contacts resulted in an ICER of $2155 per DALY averted. The addition of the Xpert MTB/RIF diagnostic test resulted in an ICER of $3275 per DALY averted within a PCF programme and $3399 per DALY averted when an ACF programme was included. Provider-initiated ACF of household contacts in an urban setting of Lima, Peru can be highly cost-effective, even including costs to seek out contacts and perform an Xpert/MTB RIF test. ACF including Xpert MTB/RIF was not cost-effective if TB cases detected had high rates of default from treatment or poor outcomes.