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The diverse morphological configurations in teeth present clinical challenges in root canal treatment, complicating instrumentation and irrigation processes, which can lead to treatment failure. Understanding anatomical variations, such as C-shaped canals and radix entomolaris, enhances clinical skills and improves long-term endodontic treatment success rates. Cone-beam computed tomography (CBCT) offers superior diagnostic capabilities over conventional radiography, enabling the pre-operative detection of root configurations and canal numbers, facilitating personalized endodontic treatments. A total of 2173 teeth of a Mexican population, including 1057 first mandibular molars and 1116 s mandibular molars, were studied using only CBCT to identify C-shaped canals and radix configurations of patients who were treated from 2018 to 2023 at the Department of Radiology at the Faculty of Dentistry, Juarez University of the State of Durango, Mexico. C-shaped canals were identified in 160 teeth, with a prevalence of 0.2% in first mandibular molars and 14.1% in second mandibular molars. The highest frequency was in the left second mandibular molar (3.7) at 14.8%. Gender differences were significant, with higher prevalence in females (27.3%) compared to males (13.3%). The most common C-shaped canal configuration was type C2 (39.3%). Radix entomolaris was found in 52 teeth, with a prevalence of 3.4% in first mandibular molars and 1.4% in second mandibular molars. This research on a Mexican population using cone-beam computed tomography (CBCT) highlights significant findings in the prevalence and types of C-shaped canals and radix entomolaris in mandibular molars for this population. The left second mandibular molar (3.7) showed the highest prevalence at 14.8%, followed closely by the right second mandibular molar (4.7) at 13.5%, with a significant difference (p < 0.001). We found a significant difference in the prevalence of C-shaped canals between genders (p = 0.004, OR 1.78). Additionally, radix entomolaris (p < 0.001) was more frequently identified in first mandibular molars to a significant degree. These insights underscore the importance of CBCT in diagnosing complex root anatomies, which can greatly enhance the success rates of endodontic procedures by allowing for more tailored and precise treatments for this population.

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Some species of the Orchidaceae family are used in Mexican traditional medicine. However, there are no current and critical compilations of the medicinal uses and pharmacological effects of the members of the Orchidaceae family. This review provides a current, critical, and comprehensive analysis of the traditional medicinal uses, pharmacological reports, and active compounds isolated from Mexican orchids. A total of 62 Mexican orchids with medicinal potential have been recorded, of which 14 have scientific evidence. The remaining 48 plant species have ethnomedicinal information but have not been validated with scientific studies. These orchids are distributed in 14 states of the Mexican Republic, mainly in the southern region of Mexico. The most common pharmacological activities reported are anti-inflammatory, vasorelaxant, antinociceptive, antioxidant, spasmolytic, antihypertensive, and hallucinogenic activities. It is necessary to increase the number of pharmacological, phytochemical, and toxicological studies with medicinal orchids from Mexico because there are scientific studies on only 22.5% of these species. In further studies, it will be possible to evaluate the pharmacological effects of Mexican orchids in clinical trials. In addition, the mechanisms of action by which plant extracts and their active compounds exert medicinal effects remain to be studied. Plant extracts from orchids and their active compounds show promising antinociceptive and spasmolytic effects, respectively.

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BACKGROUND: The spatiotemporal progression and patterns of tissue deformation in ventilator-induced lung injury (VILI) remain understudied. Our aim was to identify lung clusters based on their regional mechanical behavior over space and time in lungs subjected to VILI using machine-learning techniques. RESULTS: Ten anesthetized pigs (27 ± 2 kg) were studied. Eight subjects were analyzed. End-inspiratory and end-expiratory lung computed tomography scans were performed at the beginning and after 12 h of one-hit VILI model. Regional image-based biomechanical analysis was used to determine end-expiratory aeration, tidal recruitment, and volumetric strain for both early and late stages. Clustering analysis was performed using principal component analysis and K-Means algorithms. We identified three different clusters of lung tissue: Stable, Recruitable Unstable, and Non-Recruitable Unstable. End-expiratory aeration, tidal recruitment, and volumetric strain were significantly different between clusters at early stage. At late stage, we found a step loss of end-expiratory aeration among clusters, lowest in Stable, followed by Unstable Recruitable, and highest in the Unstable Non-Recruitable cluster. Volumetric strain remaining unchanged in the Stable cluster, with slight increases in the Recruitable cluster, and strong reduction in the Unstable Non-Recruitable cluster. CONCLUSIONS: VILI is a regional and dynamic phenomenon. Using unbiased machine-learning techniques we can identify the coexistence of three functional lung tissue compartments with different spatiotemporal regional biomechanical behavior.

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Herein, we present an innovative synthetic approach for producing a diverse set of biobased oligomers. This method begins with olive oil and employs a wide variety of commercially available amino acids (AAs) as bio-organocatalysts, in addition to tetrabutylammonium iodide (TBAI) as a cocatalyst, to synthesize various biobased oligomers. These biobased oligomers were strategically prepared starting from epoxidized olive oil (EOO) and a variety of cyclic anhydrides (phthalic, PA; maleic, MA; succinic, SA; and glutaric, GA). Among the amino acids tested as bio-organocatalysts, L-glutamic acid (L-Glu) showed the best performance for the synthesis of both poly(EOO-co-PA) and poly(EOO-co-MA), exhibiting 100% conversion at 80 °C in 2 hours, whereas the formation of poly(EOO-co-SA) and poly(EOO-co-GA) required more extreme reaction conditions (72 hours under toluene reflux conditions). Likewise, we have succeeded in obtaining the trans isomer exclusively for the MA based-oligomer within the same synthetic framework. The obtained oligomers were extensively characterized using techniques including NMR, FT-IR, GPC and TGA. A series of computational simulations based on density functional theory (DFT) and post-Hartree Fock (post-HF) methods were performed to corroborate our experimental findings and to obtain an understanding of the reaction mechanisms.

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We characterize the effect of rubidium ions on water-ice nanoislands in terms of area, fractal dimension, and apparent height by low-temperature scanning tunneling microscopy. Water nanoislands on the pristine Cu(111) surface are compared to those at similar coverage on a Rb+ pre-covered Cu(111) surface to reveal the structure-giving effect of Rb+. The presence of Rb+ induces changes in the island shape, and hence, the water network, without affecting the nanoisland volume. The broad area distribution shifts to larger values while the height decreases from three bilayers to one or two bilayers. The nanoislands on the Rb+ pre-covered surface are also more compact, reflected in a shift in the fractal dimension distribution. We relate the changes to a weakening of the hydrogen-bond network by Rb+.

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OBJECTIVES: This manuscript aims to understand the association between self-rated health and ethnic-racial characteristics (i.e., skin color, self-ascription, and Indigenous language) in the context of the Mexican population. DESIGN: Logistic regression analyses, using the 2019 PRODER (N = 7187)-a representative survey at the national level. We centered the analysis on two measures of skin color: the interviewer assessment of color skin (that has been used in previous studies), and the ITA scale, a measure constructed from optical digital colorimeter readings (a novel method in ethnoraciality studies in Mexico, included in the PRODER survey). RESULTS: In comparison to the interviewer's assessment of skin color, the ITA score shows a significant association with self-rated health, even in the presence of individual conditions, sociodemographic traits, and life-course events. In contrast, ethnic-racial self-ascriptions and speaking of an Indigenous language do not show any statistical associations. CONCLUSION: Contrary to previous research, our results suggest a positive association between skin color and self-rated health, when the former is assessed with the colorimeter readings; it means that those with lighter color skin are more prone to report a better health perception. It has methodological implications in the way skin color is observed.

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The increase in the popularity and use of electronic cigarettes (e-cigarettes) has consistently risen worldwide and has become associated with adverse health outcomes. This study has identified the attitudes and perceptions of undergraduate students who vape in three universities in Mexico. A cross-sectional study involving 495 participants was conducted using a survey from October to December 2023. Three universities in different states in Mexico collaborated with colleges in Yucatan, Durango, and Nuevo Leon, Mexico. Descriptive statistics include frequencies and percentages, and four logistic regression models were employed. In the sample, 31% and 17.54% of participants reported smoking and vaping, respectively. Students who reported vaping in the last month reported that their first experience with vaping was at an average of 17.3 years of age, and of those, 71.26% (n = 62) reported having vaped for over 100 days, while the remaining 38% reported vaping for between 2 and 100 days. Students from Veracruz and Yucatan began vaping at a younger age than in the central and northern regions. There is a need to educate students about the dangers of the chemicals in the liquids they use, the secondary exposure vapers, and the health dangers they pose.

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Post-COVID-19, schools urgently need to enhance infection control and prevention (IPC) measures, including water, sanitation, and hygiene (WASH), to prepare for future outbreaks and pandemics. Particularly in Brazil, that is of particular concern, as students are still recovering from the 20th longest school closure in the world. Hence, the current study had two goals: (i) to describe WASH solutions outlined in policies released at the federal, state, and capital city levels in Brazil during the COVID-19 pandemic for the safe reopening of schools and (ii) to discuss their potential to enhance school's capacity to remain operational during a new pandemic or outbreak. With a qualitative exploratory approach, we performed content analysis to discuss the direction (what, where, how and for whom?) of 66 public policies by integrating four frameworks. Solutions were discussed in the light of the principles of human rights and the human rights to water and sanitation, international guidelines for WASH and IPC in schools and the Sphere minimum standards for humanitarian aid. One hundred and fifty-nine solutions, spanning five thematic areas and five population groups, including software and hardware interventions, were compiled for potential use in Brazil and beyond. While suggested solutions have the potential to provide a cleaner and safer learning environment, it is essential to exercise caution when implementing these measures and adapt them to the specific circumstances of each school.

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Recent studies have linked phenolic compounds to the inhibition of digestive enzymes. Propolis extract is consumed or applied as a traditional treatment for some diseases. More than 500 chemical compounds have been identified in propolis composition worldwide. This research aimed to determine Mexican propolis extracts' total phenolic content, total flavonoid content, antioxidant activity, and digestive enzyme inhibitory activity (ɑ-amylase and ɑ-glucosidase). In vitro assays measured the possible effect on bioactive compounds after digestion. Four samples of propolis from different regions of the state of Oaxaca (Mexico) were tested (Eloxochitlán (PE), Teotitlán (PT), San Pedro (PSP), and San Jerónimo (PSJ)). Ethanol extractions were performed using ultrasound. The extract with the highest phenolic content was PE with 15,362.4 ± 225 mg GAE/100 g. Regarding the flavonoid content, the highest amount was found in PT with 8084.6 ± 19 mg QE/100 g. ABTS•+ and DPPH• radicals were evaluated. The extract with the best inhibition concentration was PE with 33,307.1 ± 567 mg ET/100 g. After simulated digestion, phenolics, flavonoids, and antioxidant activity decreased by 96%. In contrast, antidiabetic activity, quantified as inhibition of ɑ-amylase and ɑ-glucosidase, showed a mean decrease in enzyme activity of approximately 50% after the intestinal phase. Therefore, it is concluded that propolis extracts could be a natural alternative for treating diabetes, and it would be necessary to develop a protective mechanism to incorporate them into foods.

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Abdominal obesity is highly prevalent in Mexico and has a poor prognosis in terms of the severity of coronavirus disease (COVID-19) and low levels of antibodies induced by infection and vaccination. We evaluated the humoral immune response induced by COVID-19 and five different vaccination schedules in Mexican individuals with abdominal obesity and the effects of other variables. This prospective longitudinal cohort study included 2084 samples from 389 participants. The levels of anti-S1/S2 and anti-RBD IgG antibodies were measured at various time points after vaccination. A high prevalence of hospitalization and oxygen use was observed in individuals with abdominal obesity (AO) who had COVID-19 before vaccination; however, they also had high levels of anti-S1/S2 and anti-RBD-neutralizing IgG antibodies. The same was true for vaccination-induced antibody levels. However, their longevity was low. Interestingly, we did not observe significant differences in vaccine reactogenicity between abdominally obese and abdominally non-obese groups. Finally, individuals with a higher body mass index, older age, and previous COVID-19 had higher levels of antibodies induced by COVID-19 and vaccination. Therefore, it is important to evaluate other immunological and inflammatory factors to better understand the pathogenesis of COVID-19 in the presence of risk factors and to propose effective vaccination schedules for vulnerable populations.

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Breast cancer is one of the main causes of death worldwide. Lately, there is great interest in developing methods that assess individual sensitivity and/or resistance of tumors to antineoplastics to provide personalized therapy for patients. In this study we used organotypic culture of human breast tumor slices to predict the experimental effect of antineoplastics on the viability of tumoral tissue. Samples of breast tumor were taken from 27 patients with clinically advanced breast cancer; slices were obtained and incubated separately for 48 h with paclitaxel, docetaxel, epirubicin, 5-fluorouracil, cyclophosphamide, and cell culture media (control). We determined an experimental tumor sensitivity/resistance (S/R) profile by evaluating tissue viability using the Alamar Blue® metabolic test, and by structural viability (histopathological analyses, necrosis, and inflammation). These parameters were related to immunohistochemical expression of the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. The predominant histological type found was infiltrating ductal carcinoma (85.2%), followed by lobular carcinoma (7.4%) and mixed carcinoma (7.4%). Experimental drug resistance was related to positive hormone receptor status in 83% of samples treated with cyclophosphamide (p = 0.027). Results suggest that the tumor S/R profile can help to predict personalized therapy or optimize chemotherapeutic treatments in breast cancer.

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Patent ductus arteriosus (PDA) is frequent in preterm newborns, and its incidence is inversely associated with the degree of prematurity. The first choice of pharmacological treatment is ibuprofen. Several genes, including EPAS1, have been proposed as probable markers associated with a genetic predisposition for the development of PDA in preterm infants. EPAS 1 NG_016000.1:g.84131C>G or rs7557402 has been reported to be probably benign and associated with familial erythrocytosis by the Illumina Clinical Services Laboratory. Other variants of EPAS1 have been previously reported to be benign for familial erythrocytosis because they decrease gene function and are positive for familial erythrocytosis because the overexpression of EPAS1 is a key factor in uncontrolled erythrocyte proliferation. However, this could be inconvenient for ductal closure, since for this process to occur, cell proliferation, migration, and differentiation should take place, and a decrease in EPAS1 gene activity would negatively affect these processes. Single-nucleotide polymorphisms (SNPs) in EPAS1 and TFAP2B genes were searched with high-resolution melting and Sanger sequencing in blood samples of preterm infants with hemodynamically significant PDA treated with ibuprofen at the National Institute of Perinatology. The variant rs7557402, present in the EPAS1 gene eighth intron, was associated with a decreased response to treatment (p = 0.007, OR = 3.53). The SNP rs7557402 was associated with an increased risk of pharmacological treatment failure. A probable mechanism involved could be the decreased activity of the product of the EPAS1 gene.

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Obesity is associated with an increased risk of contracting infections. This study aimed to estimate the risk of COVID-19 infection associated with obesity and to assess its role in the specific antibody response against SARS-CoV-2 in 2021. This study included 980 participants from the State of Mexico who participated in a serological survey where they were tested for SARS-CoV-2 IgG anti-S1/S2 and anti-RBD antibodies and asked for height, weight, and previous infection data via a questionnaire. Of the cohort of 980 participants, 451 (46.02%) were seropositive at the time of recruitment (45.2% symptomatic and 54.8% asymptomatic). The risk of SARS-CoV-2 infection with obesity was 2.18 (95% CI: 1.51-3.16), 2.58 (95% CI: 1.63-4.09), and 1.88 (95% CI: 1.18-2.98) for seropositive, asymptomatic, and symptomatic individuals, respectively, compared to those with normal weight. Anti-S1/S2 and anti-RBD IgG antibodies tended to be higher in overweight and obese participants in the seropositive group and stratified by different obesity classes. Additionally, there was a positive correlation between anti-S1/S2 and anti-RBD IgG antibodies and BMI in both men and women in the seropositive group. Obesity is an independent risk factor for SARS-CoV-2 infection when adjusted for confounding variables; however, the relationship between BMI and anti-S1/S2 and anti-RBD IgG antibody levels differed markedly in the presence or absence of symptoms.

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This study was to evaluate whether selenium and vitamin-E counteract the toxic effects of arsenic on reproductive aspects and physiological conditions of male goats. Male goats [Criollo, n = 20, 4-5 yr-old, 72 kg live weight (LW)] were distributed in homogeneous groups (n = 5), and received during 12 weeks: (1) Sodium arsenite 2 mg/kg of LW/day (AG, LW = 69 kg); (2) Sodium selenite 6 mg + vitamin-E 420 I.U. every 14 days during the 12 weeks (SG, LW = 68 kg); (3) Both AG and SG treatments (ASG, LW = 77 kg); and (4) 1 mL of physiological solution every 14 days during the 12 weeks (CG, LW = 72 kg). The animals had access to water from a well with a concentration of 35 µg/L of arsenic. The SG had the highest percentage of sperm viability (80.6%) followed by the CG, ASG (74.7; p > 0.05), and AG (64.3; p ≤ 0.05). The ASG and SG had a lower heart rate as compared to the CG and AG (58.8, 58 vs. 65.4, 63.5; respectively, p ≤ 0.05). The CG and SG showed a lower respiratory rate than the AG and ASG (19.2, 18.7 vs. 22.1, 21.0, respectively; p ≤ 0.05). Selenium and vitamin-E were efficient in reducing the damage caused by sodium arsenite in sperm quality and maintaining heart and respiratory rates and increases in odor in male goats.

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Biomass is widely considered as a raw material for the production of biochemicals and biofuels and among all the options for its use, the gasification process is the most popular due to its environmental advantages. The great arrival of sargassum to the coasts of the State of Quintana Roo, Mexico, which has taken place for several years, forces us to study its energy use. In this study, the experimental results of the gasification of four biomasses (pine sawdust, bamboo dust, rice husk, and cane bagasse) from three different bibliographical references were simulated and validated, using the Aspen Plus computer software. The simulation model used considers the combustion of 30% of the biomass and therefore an energy balance, in addition to an estimate of the tar generated in the process. Based on the comparison of the percentage molar composition and the heating value of the syngas obtained the performance of the process was evaluated, where the lowest error per difference was for the validation of rice husk (RH) with an ER of 0.35. Subsequently, the sargassum gasification simulation was carried out with information on the properties of this biomass from five bibliographic references, obtaining as a result a syngas with a lower heating value (LHV) that varies between 2.6 and 4.8 MJ/Nm3 for ER of 0.3 and 0.35, respectively.

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Objetivo: el estiramiento muscular se aplica con el propósito de aumentar el arco de movimiento. Para este propósito se usan diferentes técnicas, entre ellas: la facilitación neuromuscular propioceptiva (FNP) y el estiramiento dinámico, pero aún no se conoce cuál de ellas es más efectiva. El objetivo de esta investigación fue estimar la eficacia de la técnica sostener relajar en comparación con el estiramiento dinámico sobre la flexibilidad de los isquiotibiales en adultos jóvenes sanos. Metodología: ensayo clínico controlado aleatorizado, con enmascaramiento de dos brazos. En el estudio participaron un total de 32 voluntarios adultos jóvenes con edades entre los 18 y 30 años y fueron aleatorizados a dos grupos de intervención FNP (n = 16), dinámico (n = 16). La flexibilidad de la articulación de la rodilla se evaluó mediante el ángulo poplíteo a través de la goniometría. Resultados: los resultados de las medias edad, peso, talla e índice masa corporal son equivalentes, lo que indica grupos comparables entre sí. No se hallaron diferencias entre los grupos de estiramiento en los promedios ajustados -2.09 (IC95% -7.05 a 2.87). Conclusiones: tanto la técnica dinámica como la FNP aumentaron el arco de movimiento de rodilla, ambas técnicas de estiramiento mostraron diferencias con la línea de base. No se encontraron diferencias entre los grupos de estiramiento.

Objective: Muscle stretching is applied with the purpose of increasing range of motion. Different techniques are used for this purpose, including proprioceptive neuromuscular facilitation (PNF) and dynamic stretching, but it is still unclear which one is more effective. The objective of this research was to estimate the efficacy of the hold-relax technique compared to dynamic stretching on hamstring flexibility in healthy young adults. Methodology: Randomized controlled trial with blinding, consisting of two intervention arms. The study included a total of 32 young adult volunteers aged 18 to 30 years, who were randomized into two intervention groups: PNF (n = 16) and dynamic stretching (n = 16). Knee joint flexibility was assessed using the popliteal angle measured with a goniometer. Results: The mean age, weight, height, and body mass index were found to be equivalent, indicating comparable groups. No significant differences were found between the stretching groups in the adjusted means, with a mean difference of -2.09 (95 % CI -7.05 to 2.87). Conclusions: Both dynamic stretching and PNF demonstrated an increase in knee range of motion, with both stretching techniques showing differences from the baseline. No significant differences were found between the stretching groups.

Finalidade: O alongamento muscular é aplicado com a finalidade de aumentar a ampli-tude de movimento. Para tanto, diversas técnicas são utilizadas, dentre elas: facilitação neuromuscular proprioceptiva (FNP) e alongamento dinâmico, mas ainda não se sabe qual delas é mais eficaz. O objetivo desta investigação foi estimar a eficáciada técnica segurar-relaxar em comparação com o alongamento dinâmico na flexibilidade dos isquiotibiais em adultos jovens saudáveis. Metodologia: Ensaio clínico randomizado, cego, controlado por dois braços. Um total de 32 voluntários adultos jovens com idades entre 18 e 30 anos participaram do estudo e foram randomizados para dois grupos de intervenção FNP (n = 16), dinâmico (n = 16). A flexibilidade da articulação do joelho foi avaliada por meio do ângulo poplíteo por goniometria. Resultados: os resultados das médias de idade, peso, altura e índice de massa corporal são equivalentes, o que indica grupos comparáveis entre si. Não foram encontradas dife-renças entre os grupos de alongamento nas médias ajustadas - 2,09 (IC 95 % -7,05 a 2,87). Conclusões: tanto a técnica dinâmica quanto o PNF aumentaram a amplitude de mo-vimento do joelho, ambas as técnicas de alongamento apresentaram diferenças com a linha de base. Não foram encontradas diferenças entre os grupos de alongamento.

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The transformation of cooking oils and their waste into polyesters is a challenge for circular chemistry. Herein, we have used epoxidized olive oil (EOO), obtained from cooking olive oil (COO), and various cyclic anhydrides (such as phthalic anhydride PA, maleic anhydride MA, and succinic anhydride SA) as raw materials for the preparation of new bio-based polyesters. For the synthesis of these materials, we have used the bis(guanidine) organocatalyst 1 and tetrabutylammonium iodide (Bu4NI) as cocatalyst. The optimal reaction conditions for the preparation of poly(EOO-co-PA) and poly(EOO-co-MA) were 80 °C for 5 h using toluene as solvent; however, the synthesis of poly(EOO-co-SA) required more extreme reaction conditions. Furthermore, we have exclusively succeeded in obtaining the trans isomer for MA-polyester. The obtained biopolyesters were characterized by NMR, Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy analyses. Since there are few examples of functionalized and defined compounds based on olive oil, it is innovative and challenging to transform these natural-based compounds into products with high added value.

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INTRODUCTION: Dengue infection is generated by a complex interaction between DENV (Dengue Virus) and the host's immune response. Interleukin-10 is an immunoregulatory cytokine during DENV infection. The objective of this study was to investigate whether genetic variants in IL-10 could be useful as a predictive and susceptibility marker in the prognosis of DENV infection, particularly with serotype 1, and in participants with dengue without warning signs. MATERIAL AND METHODS: A study of cases (n = 365) and controls (n = 364) was carried out. Genotyping was performed by real-time PCR using TaqMan probes. Sample size power was calculated using Quanto software RESULTS: This is the first report showing the independent association of the T allele of rs1800871 (P = 0.023) and the A allele of rs1800872 (P = 0.010) with the risk of dengue infection. Statistical analysis established the genotypic association of IL-10 SNPs with DENV infection under different inheritance models. Our results also showed the association of the CC, TC, and CA haplotypes (P = 0.0064, P = 0.0032, and P = 0.0010 respectively) with infection. Furthermore, both polymorphic sites were associated with the risk of DwoWS and serotype 1 (Den-1) under different inheritance models. Finally, under the dominant model, we identified a positive correlation between IL-10 levels vs. IFN-γ and IL-8. CONCLUSION: Our results show the first independent association of the T and A alleles of the polymorphic sites rs1800871 and rs1800872, with dengue infection, particularly with Den-1, and in participants with DwoWs.

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The WHO has approved the use of several vaccines during the COVID-19 pandemic; experience over the last 2 years has indicated that dose demand can only be covered using more than one design. Therefore, having scientific evidence of the performance of the different vaccines applied in a country is highly relevant. In Mexico, 5 vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were used, allowing a cohort study to analyze the generation of anti-S1/S2 IgG antibodies and anti-RBD antibodies with neutralizing activity at 0, 21, 90, and 180 days after vaccination. Five groups of participants were formed on the basis of the type of vaccine received and were divided on the basis of whether they previously had or did not have COVID-19. After completing the vaccination schedule, the seroprevalence was 95.5, 97.5, 81.0, 95.2, and 90.0% (BNT162b2, AZD1222, Convidecia, Sputnik V, and CoronaVac, respectively). Among the participants without COVID-19 prior to vaccination, the largest amount of antibodies in the 90-day period was observed in the BNT162b2 group, and the amount of antibodies in the Sputnik V group decreased the least over time. Even though the percentages of seroconversion obtained in this study were lower than those currently reported in other parts of the world, the tested vaccines are able, in most cases, to induce a good production of IgG antibodies anti-S1/S2 and neutralizing capacity. The fact that there are people who have not produced antibodies during the study leaves open some questions that must be investigated to avoid the appearance of serious cases of COVID-19. IMPORTANCE Since the start of the vaccination programs against COVID-19 in 2020, it was evident that due to global shortages, the demand for the dose required in Mexico could only be covered by acquiring different vaccines. Therefore, determining the effectiveness of these and the longevity of acquired immunity is extremely important in a scenario where SARS-CoV-2 circulation becomes endemic and booster doses are required periodically. Our data reveal significant differences both in the generation of antibodies as well as in their longevity for the vaccines applied in the country but suggest that, in general, the Mexican population can reach a high capacity to neutralize the virus, therefore, regarding less the variant for which they were designed.

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The previous paucity of data and research on water, sanitation and hygiene (WASH) in schools in Brazil have been preventing an assessment of how safe and healthy schools are to reopen during the COVID-19 pandemic. This study aimed first to assess the current situation of WASH in schools in Brazil and, second, to evaluate to what extent Brazilian schools have been making any progress in providing WASH since the beginning of the COVID-19 pandemic. Data on WASH conditions in schools in Brazil was retrieved from the 2020 and 2021 Brazilian National School Census (BNSC). For the first objective, frequencies of 31 variables were calculated for the whole country and regions, considering all 173,700 schools from BNSC of 2021. Five main variables were considered as indicators of adequate WASH infrastructure in schools. T-test and ANOVA were used to assess differences in these five variables according to the locality, management model and regions. For the second objective only schools presented in both datasets (n = 170,422) were considered to compare WASH in schools pre- and peri-COVID-19 pandemic. Frequencies of 31 variables were calculated for the whole country and regions before and during the pandemic. Paired t-tests were conducted when differences in variables across the years were observed. At the present moment, the majority of schools in Brazil have bathrooms (97%), drinking water with quality suitable for human consumption (95%), improved sanitation facilities (78%) and solid waste collection (70%). Between 2020 and 2021, there was a mix of improvements and deterioration in the school's WASH infrastructure in all regions of the country. Overall, solely considering the WASH infrastructure, schools in the South and Southeast regions of the country are better prepared for the safe reopening. Nevertheless, public schools, schools located in rural areas and the North and Northeast regions of the country, are more in need of WASH interventions. Results indicate that little progress was achieved, and schools in Brazil are still in need of improvements.

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