Use of Private Sector Workforce Respiratory Disease Short-Term Disability Claims to Assess SARS-CoV-2, Mexico, 2020

We examined respiratory disease short-term disability claims submitted to the Mexican Social Security Institute during 2020. A total of 1,631,587 claims were submitted by 19.1 million insured workers. Cumulative incidence (8.5%) was 3.6 times higher than that for January 2015‒December-2019. Workers in healthcare, social assistance, self-service, and retail stores were disproportionately affected.     

Multi‐tissue cytogenetic analysis for the diagnosis of mosaic Down syndrome: A case report

Less than one percent of individuals with Down syndrome exhibit mosaicism, a biological phenomenon that describes an individual who has two or more genetically distinct cell lines. The percentage of mosaicism in different tissues can impact the presence of clinical findings and hinder cytogenetic diagnosis. We report a case of mosaicism for trisomy 21 diagnosed after multi‐tissue cytogenetic analysis of peripheral blood and buccal mucosa, associated with significant intellectual disability, dysmorphic facial features, congenital heart defects, macropenis, and imperforate anus.     

Coupled CH4 production and oxidation support CO2 supersaturation in a tropical flood pulse lake (Tonle Sap Lake,Cambodia)

Carbon dioxide (CO₂) supersaturation in lakes and rivers worldwide is commonly attributed to terrestrial–aquatic transfers of organic and inorganic carbon (C) and subsequent, in situ aerobic respiration. Methane (CH₄) production and oxidation also contribute CO₂ to freshwaters, yet this remains largely unquantified. Flood pulse lakes and rivers in the tropics are hypothesized to receive large inputs of dissolved CO₂ and CH₄ from floodplains characterized by hypoxia and reducing conditions. We measured stable C isotopes of CO₂ and CH₄, aerobic respiration, and CH₄ production and oxidation during two flood stages in Tonle Sap Lake (Cambodia) to determine whether dissolved CO₂ in this tropical flood pulse ecosystem has a methanogenic origin. Mean CO₂ supersaturation of 11,000 ± 9,000 μatm could not be explained by aerobic respiration alone. ¹³C depletion of dissolved CO₂ relative to other sources of organic and inorganic C, together with corresponding ¹³C enrichment of CH₄, suggested extensive CH₄ oxidation. A stable isotope-mixing model shows that the oxidation of ¹³C depleted CH₄ to CO₂ contributes between 47 and 67% of dissolved CO₂ in Tonle Sap Lake. ¹³C depletion of dissolved CO₂ was correlated to independently measured rates of CH₄ production and oxidation within the water column and underlying lake sediments. However, mass balance indicates that most of this CH₄ production and oxidation occurs elsewhere, within inundated soils and other floodplain habitats. Seasonal inundation of floodplains is a common feature of tropical freshwaters, where high reported CO₂ supersaturation and atmospheric emissions may be explained in part by coupled CH₄ production and oxidation.

Globally, most lakes and rivers are supersaturated with dissolved carbon dioxide (CO₂) relative to the atmosphere, highlighting their outsized role in transferring and transforming terrestrial carbon (C) (1–3). Terrestrial–aquatic transfers of C can include CO₂ dissolved in terrestrial ground and surface waters (3–6), dissolved inorganic carbon (DIC) from carbonate weathering (7, 8), or organic C from various sources that is subsequently respired in lakes and rivers (9, 10). Initially, oceanic export was thought to be the only fate for terrestrial–aquatic transfers of C, but a growing body of research on sediment burial of organic C and CO₂ emissions from freshwaters prompted the “active pipe” revision to this initial set of assumptions (11). Although freshwaters are now recognized as focal points for transferring and transforming C on the landscape, most of this research has been conducted within temperate freshwaters (2, 11, 12). Few studies focus on the mechanisms of CO₂ supersaturation in tropical lakes and rivers, with most conducted in just one watershed, the Amazon (4, 13–15).CO₂ supersaturation within tropical freshwaters is likely influenced by their unique flood pulse hydrology. The canonical flood pulse concept hypothesizes that annual flooding of riparian land will lead to organic C mobilization and respiration (16). Partial pressures of CO₂ (pCO₂) have been measured in excess of 44,000 μatm in the Amazon River (13), 16,000 μatm in the Congo River (17), and 12,000 μatm in the Lukulu River (17). Richey et al. (13), Borges et al. (18), and Zuidgeest et al. (17) have each shown that that riverine pCO₂ scales with the amount of land flooded in these watersheds. Yet it was only recently that Abril and Borges (19) proposed the importance of flooded land to the “active pipe.” These authors differentiate uplands that unidirectionally drain water downhill (via ground and surface water) from floodplains that bidirectionally exchange water with lakes and rivers (19). They conceptualize how floodplains combine high hydrologic connectivity, high rates of primary production, and high rates of respiration to transfer relatively large amounts of C to tropical freshwaters (19).Methanogenesis inevitably results on floodplains after dissolved oxygen (O₂) and other electron acceptors for anaerobic respiration such as iron and sulfate are consumed (16, 19). Horizontal gradients in dissolved O₂ and reducing conditions have been observed extending from the center of lakes and rivers through their floodplains in the Mekong (20, 21), Congo (22), Pantanal (23), and Amazon watersheds (4). CH₄ production and oxidation occur along such redox gradients (4, 16, 19, 23). CH₄ is produced by acetate fermentation (Eq. 1) and carbonate reduction (Eq. 2) within freshwaters (24, 25). CH₄ production coupled with aerobic oxidation results in CO₂ (Eq. 3 and ref. 25), yet no studies have quantified the relative contribution of coupled CH₄ production and oxidation to CO₂ supersaturation within tropical freshwaters.CH3COOH→CO2+CH4,[1]CO2+8H++8e−→CH4+2H2O,[2]CH4+2O2→CO2+2H2O.[3]The relative contribution of coupled CH₄ production and oxidation to CO₂ supersaturation within tropical freshwaters can be traced with stable C isotopes of CO₂ and CH₄. Methanogenesis results in CH₄ that is depleted in ¹³C (δ¹³C = −65 to −50‰ from acetate fermentation and −110 to −60‰ from carbonate reduction) compared to other potential sources of organic and inorganic C (δ¹³C = −37 to −7.7‰; see Materials and Methods) (24–26). The oxidation of this ¹³C-depleted CH₄ results in ¹³C-depleted CO₂ (24–26). At the same time, CH₄ oxidation enriches the ¹³C/¹²C of residual CH₄ as bacteria and archaea preferentially oxidize ¹²C-CH₄ (25). This means that the ¹³C/¹²C of CO₂ and CH₄ can serve as powerful tools to determine the source of CO₂ supersaturation within freshwaters.Tonle Sap Lake (TSL) is Southeast Asia’s largest lake and an understudied flood pulse ecosystem that supports a regionally important fishery (21, 22, 27). Each May through October, monsoonal rains and Himalayan snowmelt increase discharge in the Mekong River and cause one of its tributaries, the Tonle Sap River, to reverse course from southeast to northwest (21). During this course reversal, the Tonle Sap River floods TSL. The TSL flood pulse increases lake volume from 1.6 to 60 km³ and inundates 12,000 km² of floodplain for 3 to 6 mo per year (21, 27). Holtgrieve et al. (22) have shown that aerobic respiration is consistently greater than primary production in TSL (i.e., net heterotrophy), with the expectation of consistent CO₂ supersaturation. But, the partial pressures, C isotopic compositions, and ultimately the source of dissolved CO₂ in TSL remain unquantified.To quantify CO₂ supersaturation and its origins in TSL, we measured the partial pressures of CO₂ and CH₄ and compared their C isotopic composition to other potential sources of organic and inorganic C. We carried out these measurements in distinct lake environments during the high-water and falling-water stages of the flood pulse, hypothesizing that CH₄ production and oxidation on the TSL floodplain would support CO₂ supersaturation during the high-water stage. We found that coupled CH₄ production and oxidation account for a nontrivial proportion of the total dissolved CO₂ in all TSL environments and during both flood stages, showing that anaerobic degradation of organic C at aquatic–terrestrial transitions can support CO₂ supersaturation within tropical freshwaters.     

Assessment of the effects of skin microneedling as adjuvant therapy for facial melasma: a pilot study

Background

Melasma is a common chronic and relapsing acquired dyschromia. Skin microneedling was reported resulting sustained long-term improvement of recalcitrant melasma, however, the exact mechanism that promotes this skin lightening is not known. This study aimed to investigate clinical and histologic alterations promoted by skin microneedling in facial melasma.

Methods

Open pilot trial including six women with facial refractory melasma submitted to two sessions of microneedling (1.5 mm) each 30 days followed by daily triple combination and broad-spectrum sunscreen. Comparison of pretreatment (T0) and 15 days after last microneedling procedure (T45) was made by standardized pictures, skin colorimetry, MASI, MELASQoL and histological parameters (haematoxylin-eosin, picrosirius-red, periodic acid Schiff and Fontana-Masson staining).

Results

The age of the subjects varied from 34 to 46 years-old, the phototypes were III and IV (Fitzpatrick), and age of melasma onset was 20 to 38 years. Improvement of melasma was perceived in all subjects. There was a significant reduction of MASI score (?70%), MELASQoL (?55%) and increase in L* (+13%) colorimetric value (p <?0.03). All cases evidenced epithelium thickening, decrease in melanin pigmentation and densification of upper dermis collagen (p =?0.03). Patients were followed by 6 months under broad-spectrum sunscreen and triple combination without relapse.

Conclusion

In addition to classic treatment (broad-spectrum sunscreen and triple combination), skin microneedling promoted clinical and histological improvement of refractory facial melasma.

     

Recent trends in chemistry,structure, and various applications of 1-acyl-3-substituted thioureas: a detailed review

The interest in acyl thioureas has continually been escalating owing to their extensive applications in diverse fields, such as synthetic precursors of new heterocycles, pharmacological and materials science, and technology. These scaffolds exhibit a wide variety of biological activities such as antitumor, enzyme inhibitory, anti-bacterial, anti-fungal, and anti-malarial activities and find utilization as chemosensors, adhesives, flame retardants, thermal stabilizers, antioxidants, polymers and organocatalysts. In addition, the synthesis, and applications of coordination complexes of these ligands have also been overviewed. The current review is a continuation of our previous efforts in this area, focusing on the recent advancements during the period 2017 to present.

This review encapsulates the recently designed acyl thioureas, and their crystal structures, metal complexes and various applications from 2017 to present, including pharmacological aspects, chemosensing and heterogenous catalysis.