Musculoskeletal disorders and quality of life for Chilean teachers during the COVID-19 pandemic at the academic year-end.

Introduction: Schoolteachers have reported multiple demands contributing to poor perceptions regarding their quality of life and high rates of musculoskeletal disorders. However, there are few studies about the association between musculoskeletal disorders and quality of life from the end of the academic period during the COVID-19 pandemic. Objective: Evaluate musculoskeletal disorders rates and their association with quality of life perceptions among teachers from the last academic period during the COVID-19 pandemic. Participants and methods: A total sample of 161 Chilean schoolteachers was included in a cross-sectional study musculoskeletal disorders prevalence was evaluated using the Standardized Nordic Questionnaire, and quality of life was evaluated through the Short-Form 12 Health Survey Instrument. A logistic regression was applied to evaluate the association between musculoskeletal disorders and quality of life perceptions adjusted by gender, age, and contract type. Results: 98% of teachers have suffered from some type of musculoskeletal disorders during the last 12 months, and 64% have had six or more painful regions. Women showed a higher musculoskeletal disorders rate than men. The group of teachers with the most musculoskeletal disorders (≥p50) saw significantly greater risk of low scores on the physical (OR: 2.16; p < 0.05) and mental components (OR: 4.86; p < 0.01) of quality of life, regardless of gender, age, and contract type. Conclusion: High musculoskeletal disorders rates suggest that preventive and informative actions must be taken regarding these disorders in order to protect teachers' mental and physical health, considering the effects of the school year and the COVID-19 health crisis.

The Legacy of President Lázaro Cárdenas for Health Care Reform in Today's Mexico.

Mexican President Andrés Manuel López Obrador's historic election victory in 2018 marked a sharp break from past decades of neoliberal socioeconomic policies. López Obrador campaigned on the promise of deep reform, with health care high on his agenda. The public health care sector had been decimated by decades of budget cuts, eroding workers' morale and patients' confidence, and crippling all aspects of the system. This article looks back to the creation of the nation's public health care system in the early twentieth century during the administration of President Lázaro Cárdenas (1934-1940). This "universal" system was designed to implement a central social justice goal of the Mexican Revolution of health care for all. The program rested on two pillars: providing care to the nation's vast, impoverished rural population and actively engaging communities in their own health care. Our objective is to critically assess the two presidents' health care initiatives within the distinct historical contexts of their administrations.

Mastitis granulomatosa: experiencia diagnóstica y terapéutica multidisciplinaria del Hospital Argerich de Buenos Aires / Granulomatous mastitis: Multidisciplinary diagnostic and therapeutic experience at Argerich Hospital in Buenos Aires

Introducción: la mastitis granulomatosa es una enfermedad inflamatoria crónica que se presenta como un tumor mamario doloroso, asociado a abscesos y fístulas, que puede simular un carcinoma. Su etiología no es clara y se postula un mecanismo autoinmune modulado por el bacilo Corynebacterium. No existen guías diagnósticas ni algoritmos terapéuticos. En nuestro estudio analizamos las presentaciones clínicas, imágenes, cultivos y hallazgos patológicos junto con los tratamientos, resultados y evolución. Material y métodos: realizamos un estudio descriptivo, retrospectivo y observacional de las pacientes con diagnóstico de mastitis granulomatosa tratadas en nuestro hospital en el periodo 2017-2022. Resultados: se evaluaron 51 pacientes con una edad media de 38,1 años; que habían tenido embarazos y lactancia, 88,2%. Clínica: tumor palpable abscedado y/o fistulizado, 74,5%; tumor palpable doloroso 13,8%; tumor asintomático, 11,7 %; eritema nodoso, 11,7%; imágenes BIRADS 4-5: 82,3%; tamaño promedio: 3,54 cm. Patología: vacuolas quísticas asociadas a Corynebacterium en 24 biopsias (47,1%); bacteriología: cultivos positivos para Corynebacterium en 13 de 47 muestras (27,6%). Tratamiento: antiobioterapia 92,1%; inmunosupresión, 78,4% y tratamiento quirúrgico 60,7 %. Tiempo medio de inmunosupresión con corticoides 7,09 meses y con metotrexato 9,27 meses. Complicaciones: 9,8%; secuelas estéticas: 39,2% tiempo libre de enfermedad: 14,04 meses. Recurrencias: 13,7 %. Conclusiones: la búsqueda bacteriológica y patológica del Corynebacterium junto a un abordaje multidisciplinario es esencial para un tratamiento a medida del paciente en pos de lograr el mayor éxito terapéutico.(AU)

Introduction: Granulomatous mastitis is a chronic inflammatory disease that presents as a painful breast mass, associated with abscesses and fistulas, which can mimic carcinoma. Etiology is still unclear, and an autoimmune response related to Corynebacterium is postulated. There are no diagnostic guidelines or therapeutic algorithms. In our study we analyzed the clinical presentations, images, cultures, and pathological findings together with the treatments, results, and evolution. Material and methods: We carried out a descriptive, retrospective, and observational study of patients diagnosed with granulomatous mastitis treated in our hospital in the period 2017-2022. Results: 51 women. Average age 38.1 years. Pregnancies and Lactation 88.2%. Clinic: Abscessed and/or fistulized palpable mass 74.5%, painful palpable mass 13.8%. Asymptomatic mass 11.7%. Erythema Nodosum 11.7% BIRADS images 4/5: 82.3%. Average size: 3.54 cm. Pathology: Cystic vacuoles associated with Corynebacterium in 24 biopsies (47.1%). Bacteriology: positive cultures for Corynebacterium in 13 of 47 samples (27.6%). Treatment: antibiotic therapy 92.1%, immunosuppression 78.4%, surgical treatment 60.7%. Mean time of immunosuppression with corticosteroids 7.09 months and with methotrexate 9.27 months. Complications: 9.8% Aesthetic sequelae: 39.2% Disease-free time: 14.04 months. Recurrences: 13.7%. Conclusions: The bacteriological and pathological search for Corynebacterium and a patient tailor made multidisciplinary approach is essential to achieve therapeutic success.(AU)

Oligo(phenyleneethynylene)s: Shape-Tunable Building Blocks for Supramolecular Self-Assembly.

Oligo(phenyleneethynylene)s (OPEs) have attracted widespread attention due to their remarkable (opto)electronic and photophysical properties, which have enabled numerous applications. The versatile functionalization possibilities of OPEs make them unique candidates to form various shape-persistent geometries, including linear, triangular, rectangular, hexagonal and macrocyclic. However, as a result of this structural variety, it is oftentimes challenging to correlate molecular design with self-assembly properties. In this minireview, we have classified OPEs based on their molecular shapes and correlated them with their self-assembly behavior in solution. Particularly, we provide important insights into the aggregation propensity of the different molecular shapes and how to tune the association strength using various non-covalent interactions. Our classification will enable a better understanding of the structure-property correlation in OPEs, which is key to develop supramolecular functional materials.

Impact of Antigen Exposure on Outcomes and Treatment Response in Fibrotic Hypersensitivity Pneumonitis.

BACKGROUND: Patients with fibrotic hypersensitivity pneumonitis (fHP) are frequently treated with immunosuppression to slow lung function decline; however, the impact of this treatment has not been studied across different types of antigen exposure. RESEARCH QUESTION: In patients with fHP, do disease outcomes and response to treatment vary by antigen type?. STUDY DESIGN AND METHODS: A multicenter interstitial lung disease database (Canadian Registry for Pulmonary Fibrosis) was used to identify patients with fHP. The causative antigen was categorized as avian, mold, unknown, or other. Treatment was defined as mycophenolate ≥ 1,000 mg/d or azathioprine ≥ 75 mg/d for ≥ 30 days. Statistical analysis included t tests, χ2 tests, and one-way analysis of variance. Unadjusted and adjusted competing risks and Cox proportional hazards models were used to assess survival. RESULTS: A total of 344 patients were identified with the following causative antigens: avian (n = 93; 27%), mold (n = 88; 26%), other (n = 15; 4%), and unknown (n = 148; 43%). Patient characteristics and lung function were similar among antigen groups with a mean FVC % predicted of 75 ± 20. The percent of patients treated with immunosuppression was similar between antigens with 58% of patients treated. There was no change in lung function or symptom scores with the initiation of immunosuppression in the full cohort. Immunosuppression was not associated with a change in survival for patients with avian or mold antigen (avian: hazard ratio, 0.41; 95% CI, 0.11-1.59; P = .20; mold: hazard ratio, 1.13; 95% CI, 0.26-4.97; P = .88). For patients with unknown causative antigen, survival was worse when treated with immunosuppression (hazard ratio, 2.65; 95% CI, 1.01-6.92; P = .047). INTERPRETATION: Response to immunosuppression varies by antigen type in patients with fHP. Additional studies are needed to test the role of immunosuppression in fHP, and particularly in those with an unknown antigen.

Sterically Allowed H-type Supramolecular Polymerizations.

The functionalization of π-conjugated scaffolds with sterically demanding substituents is a widely used tactic to suppress cofacial (H-type) stacking interactions, which may even inhibit self-assembly. Contrary to expectations, we demonstrate herein that increasing steric effects can result in an enhanced thermodynamic stability of H-type supramolecular polymers. In our approach, we have investigated two boron dipyrromethene (BODIPY) dyes with bulky phenyl (2) and mesityl (3) meso-substituents and compared their self-assembly in nonpolar media with that of a parent meso-methyl BODIPY 1 lacking bulky groups. While the enhanced steric demand induces pathway complexity, the superior thermodynamic stability of the H-type pathways can be rationalized in terms of additional enthalpic gain arising from intermolecular C-H⋅⋅⋅F-B interactions of the orthogonally arranged aromatic substituents, which overrule their inherent steric demand. Our findings underline the importance of balancing competing non-covalent interactions in self-assembly.

Comparison of Gonadotropin-Releasing Hormone versus Estrogen-Based Fixed-Time Artificial Insemination Protocols in Grazing Bos taurus Suckled Beef Cows.

Fixed-timed artificial insemination (FTAI) protocols for beef cattle in South America are primarily based on estradiol esters and intravaginal progesterone-releasing devices (IVPD). The objective of this study was to determine the optimal gonadotropin-releasing hormone (GnRH)-based protocol as an alternative to the use of estrogen-based protocols in grazing Bos taurus suckling beef cows. All cows received an IVPD on the day of protocol initiation and prostaglandin F2α (PG) plus equine chorionic gonadotropin (eCG) treatments at the time of IVPD removal. In Experiment 1, cows (n = 235) were randomly assigned to one of four treatments: (i) 7-day estradiol = 2 mg of estradiol benzoate (EB) at IVPD insertion on Day 9 and 1 mg of estradiol cypionate (ECP) at IVPD removal on Day 2; (ii) 7-day GnRH = 10 µg of GnRH at IVPD insertion on Day 10, IVPD removal on Day 3 and GnRH at FTAI; (iii) 7 & 7 estradiol = PG at IVPD insertion on Day 16, EB on Day 9 and ECP at IVPD removal on Day 2; (iv) 7 & 7 GnRH = PG at IVPD insertion on Day 17, GnRH on Day 10, IVPD removal on Day 3 and GnRH at FTAI. In Experiment 2, cows (n = 462) were randomly assigned to one of four treatments: (i) 6-day estradiol = EB at IVPD insertion on Day 9, IVPD removal on Day 3 and GnRH at FTAI; (ii) 7-day estradiol; (iii) 7-day GnRH; (iv) 7 & 7 GnRH. In Experiment 1, plasma progesterone concentrations and percentage of cows with a corpus luteum (CL) at IVPD removal, and pregnancy per AI (P/AI) were greater for cows subjected to GnRH-based protocols compared with cows subjected to estrogen-based protocols (p < 0.01). In Experiment 2, cows subjected to the 7 & 7 GnRH protocol had the greatest P/AI (p < 0.01). In summary, GnRH-based FTAI protocols resulted in similar or greater P/AI compared to estrogen-based FTAI protocols in grazing postpartum Bos taurus suckled beef cows. The greatest P/AI was attained with the 7 & 7 GnRH protocol.

Multi-chiral materials comprising metallosupramolecular and covalent helical polymers containing five axial motifs within a helix.

Supramolecular and covalent polymers share multiple structural effects such as communication mechanisms among monomer repeating units, which are related to their axial helical structure. Herein, a unique multi-helical material combining information from both metallosupramolecular and covalent helical polymers is presented. In this system, the helical structure described by the poly(acetylene) (PA) backbone (cis-cisoidal, cis-transoidal) guides the pendant groups in a fashion where a tilting degree emerges between a pendant and the adjacent ones. As a result, a multi-chiral material is formed comprising four or five axial motifs when the polyene skeleton adopts either a cis-transoidal or cis-cisoidal configuration: the two coaxial helices-internal and external-and the two or three chiral axial motifs described by the bispyridyldichlorido PtII complex array. These results show that complex multi-chiral materials can be obtained by polymerizing appropriate monomers that combine both point chirality and the ability to generate chiral supramolecular assemblies.

Amphiphile desymmetrisation-induced steric relief governs self-assembly pathways in aqueous media.

Herein, we show that a straightforward desymmetrisation of a bolaamphiphilic chromophore can tune aromatic interactions and exciton coupling upon self-assembly. As a result, multiple assembled states become accesible offering a facile approach to induce pathway complexity in aqueous media.

Pathway-Controlled Aqueous Supramolecular Polymerization via Solvent-Dependent Chain Conformation Effects.

Solute-solvent interactions play a critical role in multiple fields, including biology, materials science, and (physical) organic, polymer, and supramolecular chemistry. Within the growing field of supramolecular polymer science, these interactions have been recognized as an important driving force for (entropically driven) intermolecular association, particularly in aqueous media. However, to date, solute-solvent effects remain poorly understood in the context of complex self-assembly energy landscapes and pathway complexity. Herein, we unravel the role of solute-solvent interactions in controlling chain conformation effects, allowing energy landscape modulation and pathway selection in aqueous supramolecular polymerization. To this end, we have designed a series of oligo(phenylene ethynylene) (OPE)-based bolaamphiphilic Pt(II) complexes OPE2-4 bearing solubilizing triethylene glycol (TEG) chains of equal length on both molecule ends, but a different size of the hydrophobic aromatic scaffold. Strikingly, detailed self-assembly studies in aqueous media disclose a different tendency of the TEG chains to fold back and enwrap the hydrophobic molecular component depending on both the size of the core and the volume fraction of the co-solvent (THF). The relatively small hydrophobic component of OPE2 can be readily shielded by the TEG chains, leading to only one aggregation pathway. In contrast, the decreased capability of the TEG chains to effectively shield larger hydrophobic cores (OPE3 and OPE4) enables different types of solvent quality-dependent conformations (extended, partly back-folded and back-folded), which in turn induce various controllable aggregation pathways with distinct morphologies and mechanisms. Our results shed light on previously underappreciated solvent-dependent chain conformation effects and their role in governing pathway complexity in aqueous media.

Patient dissatisfaction associated with physician-patient linguistic discordance in California clinics: an analytical cross-sectional study.

BACKGROUND: Patient satisfaction is considered as a product of two psychological processes, a cognitive one, including expectations and perceptions, and an emotional one resulting from the congruence between expectation and subjective perception of the user. The objective was to identify the factors associated with the level of perceived satisfaction in patients treated in 36 nonprofit health clinics that offer comprehensive health care services in four counties in the state of California, United States. METHODS: Cross-sectional analytical study in 14 clinics in four California counties. It consisted of the application of a 30-item questionnaire to determine the degree of patient satisfaction with the clinic. The factorial composition of the quality of care and clinic quality components was analyzed and two factors with an Eigen value greater than 1 were obtained. RESULTS: A total of 846 responses were registered. Factor analysis identified two underlying dimensions: Physician Attitude and Empathy. It was found that the discordance in language between the physician and the patient generates a difference in the perception of satisfaction. Patients who prefer to speak English have better satisfaction than those who speak Spanish. Spanish speakers who do not have interpreter have lower satisfaction than those who do (p < 0,01). CONCLUSIONS: The most important sociodemographic cofactor was language. Satisfaction decreased in Spanish-speaking patients who were not proficient in the use of English since they expressed fewer comments and doubts.

Anticooperative Supramolecular Oligomerization Mediated by V-Shaped Monomer Design and Unconventional Hydrogen Bonds.

After more than three decades of extensive investigations on supramolecular polymers, strategies for self-limiting growth still remain challenging. Herein, we exploit a new V-shaped monomer design to achieve anticooperatively formed oligomers with superior robustness and high luminescence. In toluene, the monomer-oligomer equilibrium is shifted to the monomer side, enabling the elucidation of the molecular packing modes and the resulting (weak) anticooperativity. Steric effects associated with an antiparallel staircase organization of the dyes are proposed to outcompete aromatic and unconventional B-F⋅⋅⋅H-N/C interactions, restricting the growth at the stage of oligomers. In methylcyclohexane (MCH), the packing modes and the anticooperativity are preserved; however, pronounced solvophobic and chain-enwrapping effects lead to thermally ultrastable oligomers. Our results shed light on understanding anticooperative effects and restricted growth in self-assembly.

Bioinspired crowding directs supramolecular polymerisation.

Crowding effects are crucial to maintaining functionality in biological systems, but little is known about their role in analogous artificial counterparts. Within the growing field of supramolecular polymer science, crowding effects have hitherto remained underappreciated. Herein, we show that crowding effects exhibit strong and distinct control over the kinetics, accessible pathways and final outcomes of supramolecular polymerisation processes. In the presence of a pre-formed supramolecular polymer as crowding agent, a model supramolecular polymer dramatically changes its self-assembly behaviour and undergoes a morphological transformation from bundled fibres into flower-like hierarchical assemblies, despite no co-assembly taking place. Notably, this new pathway can only be accessed in crowded environments and when the crowding agent exhibits a one-dimensional morphology. These results allow accessing diverse morphologies and properties in supramolecular polymers and pave the way towards a better understanding of high-precision self-assembly in nature.

The burden of cardiovascular disease in Mexico 1990-2021. Summary of the Global Burden of Disease 2021 study.

BACKGROUND: Cardiovascular disease (CVD) is a major cause of mortality, with economic implications for the health system. OBJECTIVE: To characterize the burden of CVD in Mexico from 1990 to 2021 based on the Global Burden of Disease (GBD) study, to address the burden of health and disease, its implications for public health and for the development of the health care system. MATERIAL AND METHODS: CVD mortality in Mexico is described, and the extent to which population growth and aging explain the observed trends, sex differences, and geographic patterns is examined. RESULTS: CVD is the leading cause of mortality, mainly due to hypertensive heart disease, intracerebral hemorrhage, subarachnoid hemorrhage, ischemic heart disease and ischemic stroke. A change of trend was observed in men and women, with higher mortality in people older than 80 years and in the northern states of the country. CONCLUSIONS: Mexico must invest in public health programs to address modifiable risks, promote healthy aging, and reduce premature death due to CVD.

ANTECEDENTES: La enfermedad cardiovascular (ECV) es una causa importante de mortalidad, con implicaciones económicas para el sistema de salud. OBJETIVO: Caracterizar la carga de ECV en México de 1990 a 2021 con base en el estudio Global Burden of Disease (GBD), para abordar la carga de salud y enfermedad, sus implicaciones en la salud pública y el desarrollo del sistema de atención médica. MATERIAL Y MÉTODOS: Se describe la mortalidad de las ECV en México y se examina en qué medida el crecimiento y el envejecimiento de la población explican las tendencias, las diferencias por sexo y los patrones geográficos. RESULTADOS: Las ECV representan la primera causa de mortalidad, principalmente por cardiopatía hipertensiva, hemorragia intracerebral, hemorragia subaracnoidea, cardiopatía isquémica y accidente cerebrovascular isquémico. Se observó un cambio de tendencia en hombres y mujeres, mayor mortalidad en mayores de 80 años y en estados del norte del país. CONCLUSIONES: México debe invertir en programas de salud pública para abordar los riesgos modificables, promover el envejecimiento saludable y reducir la muerte prematura por ECV.

Impact of Hydrophobic/Hydrophilic Balance on Aggregation Pathways, Morphologies, and Excited-State Dynamics of Amphiphilic Diketopyrrolopyrrole Dyes in Aqueous Media.

We report the thermodynamic and kinetic aqueous self-assembly of a series of amide-functionalized dithienyldiketopyrrolopyrroles (TDPPs) that bear various hydrophilic oligoethylene glycol (OEG) and hydrophobic alkyl chains. Spectroscopic and microscopic studies showed that the TDPP-based amphiphiles with an octyl group form sheet-like aggregates with J-type exciton coupling. The effect of the alkyl chains on the aggregated structure and the internal molecular orientation was examined via computational studies combining MD simulations and TD-DFT calculations. Furthermore, solvent and thermal denaturation experiments provided a state diagram that indicates the formation of unexpected nanoparticles during the self-assembly into nanosheets when longer OEG side chains are introduced. A kinetic analysis revealed that the nanoparticles were obtained selectively as an on-pathway intermediate state toward the formation of thermodynamically controlled nanosheets. The metastable aggregates were used for seed-initiated supramolecular assembly, which allowed establishing control over the assembly kinetics and the aggregate size. The sheet-like aggregates prepared using the seeding method exhibited coherent vibration in the excited state, indicating a well-ordered orientation of the TDPP units. These results underline the significance of fine tuning of the hydrophobic/hydrophilic balance in the molecular design to kinetically control the assembly of amphiphilic π-conjugated molecules into two-dimensional nanostructures in aqueous media.

Exploiting halido ligands to control nucleation pathways and Pt⋯Pt interactions in supramolecular co-polymerizations.

We use different halido ligands to tune metal-metal interactions, nucleation pathways and hetero-seeded growth in supramolecular copolymerizations.

Thermoreversible Polymorph Transitions in Supramolecular Polymers of Hydrogen-Bonded Squaramides.

Hydrogen-bonded squaramide (SQ) supramolecular polymers exhibit uncommon thermoreversible polymorph transitions between particle- and fiber-like nanostructures. SQs 1-3, with different steric bulk, self-assemble in solution into particles (AggI) upon cooling to 298 K, and SQs 1 and 2, with only one dendronic group, show a reversible transformation into fibers (AggII) by further decreasing the temperature to 288 K. Nano-DSC and UV/Vis studies on SQ 1 reveal a concentration-dependent transition temperature and ΔH for the AggI-to-AggII conversion, while the kinetic studies on SQ 2 indicate the on-pathway nature of the polymorph transition. Spectroscopic and theoretical studies reveal that these transitions are triggered by the molecular reorganization of the SQ units changing from slipped to head-to-tail hydrogen bonding patterns. This work unveils the thermodynamic and kinetic aspects of reversible polymorph transitions that are of interest to develop stimuli-responsive systems.

A comparison of statistical methods for modeling count data with an application to hospital length of stay.

BACKGROUND: Hospital length of stay (LOS) is a key indicator of hospital care management efficiency, cost of care, and hospital planning. Hospital LOS is often used as a measure of a post-medical procedure outcome, as a guide to the benefit of a treatment of interest, or as an important risk factor for adverse events. Therefore, understanding hospital LOS variability is always an important healthcare focus. Hospital LOS data can be treated as count data, with discrete and non-negative values, typically right skewed, and often exhibiting excessive zeros. In this study, we compared the performance of the Poisson, negative binomial (NB), zero-inflated Poisson (ZIP), and zero-inflated negative binomial (ZINB) regression models using simulated and empirical data. METHODS: Data were generated under different simulation scenarios with varying sample sizes, proportions of zeros, and levels of overdispersion. Analysis of hospital LOS was conducted using empirical data from the Medical Information Mart for Intensive Care database. RESULTS: Results showed that Poisson and ZIP models performed poorly in overdispersed data. ZIP outperformed the rest of the regression models when the overdispersion is due to zero-inflation only. NB and ZINB regression models faced substantial convergence issues when incorrectly used to model equidispersed data. NB model provided the best fit in overdispersed data and outperformed the ZINB model in many simulation scenarios with combinations of zero-inflation and overdispersion, regardless of the sample size. In the empirical data analysis, we demonstrated that fitting incorrect models to overdispersed data leaded to incorrect regression coefficients estimates and overstated significance of some of the predictors. CONCLUSIONS: Based on this study, we recommend to the researchers that they consider the ZIP models for count data with zero-inflation only and NB models for overdispersed data or data with combinations of zero-inflation and overdispersion. If the researcher believes there are two different data generating mechanisms producing zeros, then the ZINB regression model may provide greater flexibility when modeling the zero-inflation and overdispersion.

Luminescence and Length Control in Nonchelated d8 -Metallosupramolecular Polymers through Metal-Metal Interactions.

Supramolecular polymers (SPs) of d8 transition metal complexes have received considerable attention by virtue of their rich photophysical properties arising from metal-metal interactions. However, thus far, the molecular design is restricted to complexes with chelating ligands due to their advantageous preorganization and strong ligand fields. Herein, we demonstrate unique pathway-controllable metal-metal-interactions and remarkable 3 MMLCT luminescence in SPs of a non-chelated PtII complex. Under kinetic control, self-complementary bisamide H-bonding motifs induce a rapid self-assembly into non-emissive H-type aggregates (1A). However, under thermodynamic conditions, a more efficient ligand coplanarization leads to superiorly stabilized SP 1B with extended Pt⋅⋅⋅Pt interactions and remarkably long 3 MMLCT luminescence (τ77 K =0.26 ms). The metal-metal interactions could be subsequently exploited to control the length of the emissive SPs using the seeded-growth approach.

Effect of Omicron on the prevalence of COVID-19 in international travelers at the Mexico city international airport. December 16th, 2021 to January 31st, 2022.

INTRODUCTION: SARS-CoV-2 continues to have a high rate of contagion worldwide. The new variant of concern, Omicron, has mutations that decrease the effectiveness of vaccines and evade antibodies from previous infections resulting in a fourth wave of the pandemic. It was identified in Mexico in December 2021. METHODS: The Traveler's Preventive Care Clinic from the Faculty of Medicine UNAM at Mexico City International Airport has performed rapid antigen and PCR SARS CoV2 tests since January 2021 to comply with the new travel requirements. Demographic and clinical characteristics were collected from each passenger and the fourth wave of the pandemic in Mexico mainly caused by Omicron was analyzed in the travelers. RESULTS: A total of 5176 travelers attended the clinic between the second half of December 2021 and January 2022. Ten percent of all the tests performed were positive (13% of PCR and 9.3% of antigens, p = 0.001). Most of the SARS CoV2 positive cases were asymptomatic (78%), with a ratio of 3.5:1 over the symptomatic. By age groups, this ratio was higher for those under 20 years old (8.7:1). DISCUSSION: This study shows the rapid escalation of positivity that occurred in Mexico, detected in travelers, from the second half of December 2020 and throughout the month of January 2021. The incidence of COVID-19 was extremely high in travelers who were mostly asymptomatic for the period under study.