Efficient carbene transfer reactivity mediated by Fe(II) complexes supported by bulky alkoxides.

Herein we describe the stoichiometric and catalytic carbene-transfer reactivity of iron(II) alkoxide complexes with iodonium ylide precursors. Treatment of PhIC(CO2Me)2 with styrene in the presence of catalytic amounts of several different Fe(OR)2(THF)2 precursors results in efficient cyclopropanation for a variety of styrenes. Computational and reactivity studies suggest a novel remote metallocarbene/vinyl radical intermediate, Fe(OR)2(κ2-(OC(OMe))2C), which could be responsible for the reactive nature of the catalyst.

Valorization of Agricultural Rice Straw as a Sustainable Feedstock for Rigid Polyurethane/Polyisocyanurate Foam Production.

Agricultural rice straw (RS), often discarded as waste in farmlands, represents a vast and underutilized resource. This study explores the valorization of RS as a potential feedstock for rigid polyurethane/polyisocyanurate foam (RPUF) production. The process begins with the liquefaction of RS to create an RS-based polyol, which is then used in a modified foam formulation to prepare RPUFs. The resulting RPUF samples were comprehensively characterized according to their physical, mechanical, and thermal properties. The results demonstrated that up to 50% by weight of petroleum-based polyol can be substituted with RS-based polyol to produce a highly functional RPUF. The obtained foams exhibited a notably low apparent density of 18-24 kg/m3, exceptional thermal conductivity ranging from 0.031-0.041 W/m-K, and a high compressive strength exceeding 250 kPa. This study underlines the potential of the undervalued agricultural RS as a green alternative to petroleum-based feedstocks to produce a high-value RPUF. Additionally, the findings contribute to the sustainable utilization of abundant agricultural waste while offering an eco-friendly option for various applications, including construction materials and insulation.

Whole Genome Sequencing Reveals High Genetic Diversity, Diverse Repertoire of Virulence-Associated Genes and Limited Antibiotic Resistance Genes among Commensal Escherichia coli from Food Animals in Uganda.

Commensal Escherichia coli with broad repertoire of virulence and antimicrobial resistance (AMR) genes pose serious public health risks as reservoirs of AMR and virulence. This study undertook whole genome characterization of commensal E. coli from food-producing animals in Uganda to investigate their genome variability (resistome and virulome). We established that the E. coli had high genomic diversity with 38 sequence types, 24 FimH types, and 33 O-antigen serotypes randomly distributed within three phylogroups (A, B1, and E). A greater proportion (≥93.65%) of the E. coli were resistant to amoxicillin/clavulanate and ampicillin antibiotics. The isolates were AmpC beta-lactamase producers dominated by blaEC-15 (71.88%) and tet(A) (20.31%) antimicrobial resistant genes besides a diverse armory of virulence-associated genes in the class of exotoxin, adhesins, iron uptake, and serine protease autotransporters which varied by host species. Cattle were found to be the major source of E. coli carrying Shiga toxin genes, whereas swine was the main source of E. coli carrying colicin-like Usp toxin gene. The study underscores the importance of livestock as the carrier of E. coli with antimicrobial resistance and a large repertoire of virulence traits with a potential of causing disease in animals and humans by acquiring more genetic traits.

Changes in Coleopteran assemblages over a successional chronosequence in a Mexican tropical dry forest.

Coleopterans are the most diverse animal group on Earth and constitute good indicators of environmental change. However, little information is available about Coleopteran communities' responses to disturbance and land-use change. Tropical dry forests have undergone especially extensive anthropogenic impacts in the past decades. This has led to mosaic landscapes consisting of areas of primary forest surrounded by pastures, agricultural fields and secondary forests, which negatively impacts many taxonomic groups. However, such impacts have not been assessed for most arthropod groups. In this work, we compared the abundance, richness and diversity of Coleopteran morphospecies in four different successional stages in a tropical dry forest in western Mexico, to answer the question: How do Coleopteran assemblages associate with vegetation change over the course of forest succession? In addition, we assessed the family composition and trophic guilds for the four successional stages. We found 971 Coleopterans belonging to 107 morphospecies distributed in 28 families. Coleopteran abundance and richness were greatest for pastures than for latter successional stages, and the most abundant family was Chrysomelidae, with 29% of the individuals. Herbivores were the most abundant guild, accounting for 57% of the individuals, followed by predators (22%) and saprophages (21%) beetles. Given the high diversity and richness found throughout the successional chronosequence of the studied tropical dry forest, in order to have the maximum number of species associated with tropical dry forests, large tracts of forest should be preserved so that successional dynamics are able to occur naturally.

Implementing High Q-Factor HTS Resonators to Enhance Probe Sensitivity in 13C NMR Spectroscopy.

Nuclear magnetic resonance spectroscopy (NMR) probes using thin-film high temperature superconducting (HTS) resonators provide exceptional mass sensitivity in small-sample NMR experiments for natural products chemistry and metabolomics. We report improvements in sensitivity to our 1.5 mm 13C-optimized NMR probe based on HTS resonators. The probe has a sample volume of 35 microliters and operates in a 14.1 T magnet. The probe also features HTS resonators for 1H transmission and detection and the 2H lock. The probe utilizes a 13C resonator design that provides greater efficiency than our previous design. The quality factor of the new resonator in the 14.1 T background field was measured to be 4,300, which is over 3x the value of the previous design. To effectively implement the improved quality factor, we demonstrate the effect of adding a shorted transmission line stub to increase the bandwidth and reduce the rise/fall time of 13C irradiation pulses. Initial NMR measurements verify 13C NMR sensitivity is significantly improved while preserving detection bandwidth. The probe will be used for applications in metabolomics.

Substance Use in Healthcare Professionals During the COVID-19 Pandemic in Latin America: A Systematic Review and a Call for Reports.

Background: The COVID-19 pandemic has generated a remarkable change in the behaviour of Healthcare workers (HCWs) around the world. However, there is a lack of evidence on substance use among HCWs in Latin America. Therefore, this study aimed to determine the current frequency of substance use among Latin American among HCWs. Methods: We searched 8 databases (PubMed, Scopus, ScientDirect, Web of Science, Cochrane, Scielo, LILACS and Latindex), 4 public prepublication servers (SocArXiv, medRxiv, bioRxiv and Preprints) and Google scholar from 1/9/2019 to 11/1/2021. We determined the frequency of each study based on original studies, scientific letters, and clinical trials in English, Spanish and Portuguese. Results: A total of 17 175 study articles were identified from electronic databases and preprints, and 2 cross-sectional studies conducted in 2020 were included in the qualitative analysis. Both studies included HCWs but did not perform a differential analysis. The first was developed by the Pan-American Health Organization and included interviewees from 35 countries, while the second was conducted with 1145 Brazilian participants. Both studies showed increases in substance use during the pandemic, with alcohol being the most commonly used substance (30%), but PAHO's study reported a 13.8% increase in self-reported heavy-episodic drinking, with differences among genders (males, 15.4%), age groups (highest increase in the 40-49 age group, 16.5%) and area of residence (urban with 14%). The second study showed that 21 32% of participants reported initiating psychoactive substance use, 29.3% added some substance to their initial use and 4% of them had to replace the substance, mainly due to difficulty of access. Other substances of abuse that showed significant increases were tobacco (0.5%) and marijuana (0.3%). Conclusion: Overall, despite the analysis of the 2 studies, the results provided are not a conclusive description of the frequency of substance use by HCWs in Latin America during the COVID-19 pandemic. Further research is required to understand the impact of the pandemic on drug abuse in the region. Protocol Registration: The protocol has been registered on 30 November 2021 on the International Prospective Register of Systematic Reviews (PROSPERO) with ID: CRD420212919700.

Addressing the Data Acquisition Paradigm in the Early Detection of Pediatric Foot Deformities.

The analysis of plantar pressure through podometry has allowed analyzing and detecting different types of disorders and treatments in child patients. Early detection of an inadequate distribution of the patient's weight can prevent serious injuries to the knees and lower spine. In this paper, an embedded system capable of detecting the presence of normal, flat, or arched footprints using resistive pressure sensors was proposed. For this purpose, both hardware- and software-related criteria were studied for an improved data acquisition through signal coupling and filtering processes. Subsequently, learning algorithms allowed us to estimate the type of footprint biomechanics in preschool and school children volunteers. As a result, the proposed algorithm achieved an overall classification accuracy of 97.2%. A flat feet share of 60% was encountered in a sample of 1000 preschool children. Similarly, flat feet were observed in 52% of a sample of 600 school children.

Influence of Land Use on the C and N Status of a C4 Invasive Grass in a Semi-Arid Region: Implications for Biomonitoring.

Biomonitoring of atmospheric pollution is an increasingly accepted practice. However, most existing biomonitors are usually epiphytic species from mesic environments. This work assessed the suitability of buffelgrass (Cenchrus ciliaris), an invasive C4 grass in northwestern Mexico, as a biomonitor, by means of the spatial distribution of the carbon and nitrogen content and isotopic signatures for grass samples collected from urban, agricultural, and natural areas throughout the state of Sonora. We found the highest tissue carbon content of 45.6% (on a dry weight basis) and highest nitrogen content of 3.31% for buffelgrass from the Yaqui Valley. We also found the lowest δ13C of -15.9‰, and the highest δ15N of 16.7‰ in the same region. In contrast, the lowest carbon and nitrogen content of 39.4 and 1.49% were found for Bahía de Kino and Río Sonora mountains, respectively. The lowest δ15N of 2.18‰ and the highest δ13C of -13.7‰ were measured for two remote locations. These results show the influence that pollutant emissions, including agriculture and transportation, have on elemental and isotopic composition of vegetation. Buffelgrass is most adequate for tracking carbon and nitrogen emissions in arid environments and for determining alterations on nitrogen soil reactions, as a first approximation for saturation.

Motor Impairment and Its Influence in Gait Velocity and Asymmetry in Community Ambulating Hemiplegic Individuals.

OBJECTIVES: To determine the most important motor impairments that are predictors of gait velocity and spatiotemporal symmetrical ratio in patients with stroke. DESIGN: Cross-sectional, descriptive analysis study. SETTING: Human performance laboratory of the University of Santo Tomas. PARTICIPANTS: Individuals with chronic stroke (N=55; 34 men, 21 women) who are community dwellers. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The gait velocity and spatiotemporal symmetrical ratio (step length; step, stance, swing, single-leg support, and double-leg support stance times) was determined using Vicon motion capture. We also calculated motor impairment of the leg and foot using Brunnstrom's stages of motor recovery, evaluated muscle strength using the scoring system described by Collin and Wade, and assessed spasticity using by the modified Ashworth Scale. RESULTS: Regression analysis showed that plantarflexor strength is a predictor of gait velocity and all temporospatial symmetry ratio. Knee flexor and extensor strength are predictors in single-leg support time and double-leg support time symmetry ratio, respectively. On the other hand, hip adductor and quadriceps spasticity are predictors of swing time and step length symmetry ratio. CONCLUSION: Different motor impairments are predictors of stroke gait abnormality. Interventions should be focused on these motor impairments to allow for optimal gait rehabilitation results.

13C-Optimized HTS NMR RF Coil Design at 21.1 T.

We present the design of a novel high-temperature superconductor double-sided racetrack resonator for a 13C optimized nuclear magnetic resonance (NMR) transmitter/receiver coil. The coils operate in a 21.1 T magnet and accommodate a 3 mm × 6.2 mm cross-section rectangular sample tube. The design includes the incorporation of revised finger lengths to improve the homogeneity of current density across the fingers, a new laser trimming approach for adjusting the resonance frequency, and improved ability to shift higher-order modes for suitability in 1H/13C NMR probes. Resonator design methodology, simulations and experimental results are presented.

Spatiotemporal parameters of gait in Filipino adults using the 3-D motion capture system

@#<p style="text-align: justify;"><strong>Background and Purpose:</strong> Gait is one of the outcome measures used in evaluation in the field of rehabilitation and there is a need for reference data of gait parameters primarily to understand the physiological significance of these parameters, describe their changes in pathologic gait for better understanding of pathophysiology and be able to provide the appropriate therapeutic approach. The purpose of this study was: 1) To derive a reference data of spatiotemporal parameters of gait among Filipinos, which include step time, stride time, stance time, swing time, single limb support time, double limb support time, cadence, speed, step length, stride length, and step width; 2) To determine correlation of age, gender, and anthropometric measures with spatiotemporal parameters, and 3) To determine<br />gait symmetry.</p><p style="text-align: justify;"><strong>Materials and Methods:</strong> In this cross-sectional study, 374 participants aged 20-69 years (males = 181, females = 193) were included. They were asked to walk in their comfortable speed. Spatiotemporal parameters were obtained using the Vicon motion capture system.</p><p style="text-align: justify;"><strong>Results:</strong> The walking speed, step length, stride length, and step width declined with age. Filipino men demonstrated higher values in all parameters except cadence which is higher in Filipino women. Height and leg length both have positive correlation with all parameters except for cadence. Weight has a positive correlation with all spatiotemporal parameters except for cadence, swing time, single limb support time, and speed. Cadence and stride length were symmetrical between right and left lower extremities.</p><p style="text-align: justify;"><strong>Conclusion:</strong> Spatiotemporal parameters among healthy Filipinos 20-69 years old were presented including their correlations with age, gender, and anthropometric measures. This can serve as a reference for future studies in gait where Filipinos are the participants.</p>

Prospects on Nano-Based Platforms for Antimicrobial Photodynamic Therapy Against Oral Biofilms.

Objective: This review clusters the growing field of nano-based platforms for antimicrobial photodynamic therapy (aPDT) targeting pathogenic oral biofilms and increase interactions between dental researchers and investigators in many related fields. Background data: Clinically relevant disinfection of dental tissues is difficult to achieve with aPDT alone. It has been found that limited penetrability into soft and hard dental tissues, diffusion of the photosensitizers, and the small light absorption coefficient are contributing factors. As a result, the effectiveness of aPDT is reduced in vivo applications. To overcome limitations, nanotechnology has been implied to enhance the penetration and delivery of photosensitizers to target microorganisms and increase the bactericidal effect. Materials and methods: The current literature was screened for the various platforms composed of photosensitizers functionalized with nanoparticles and their enhanced performance against oral pathogenic biofilms. Results: The evidence-based findings from the up-to-date literature were promising to control the onset and the progression of dental biofilm-triggered diseases such as dental caries, endodontic infections, and periodontal diseases. The antimicrobial effects of aPDT with nano-based platforms on oral bacterial disinfection will help to advance the design of combination strategies that increase the rate of complete and durable clinical response in oral infections. Conclusions: There is enthusiasm about the potential of nano-based platforms to treat currently out of the reach pathogenic oral biofilms. Much of the potential exists because these nano-based platforms use unique mechanisms of action that allow us to overcome the challenging of intra-oral and hard-tissue disinfection.

Isotopic biomonitoring of anthropic carbon emissions in a megalopolis.

Atmospheric pollution has become a serious threat for human health and the environment. However, the deployment, operation and maintenance of monitoring networks can represent a high cost for local governments. In certain locations, the use of naturally occurring plants for monitoring pollution can be a useful supplement of existing monitoring networks, and even provide information when other types of monitoring are lacking. In this work, we (i) determined the tissue carbon content and the δ13C values for the epiphytic CAM bromeliad Tillandsia recurvata and the relationship of both parameters with the existing CO concentrations in the Valley of Mexico basin and (ii) mapped the spatial distribution of such elemental and isotopic composition for this plant within the basin, in order to assess its potential as an atmospheric biomonitor of carbon monoxide, a pollutant with important repercussions on public health. The CO concentrations in the basin ranged from 0.41 ppm at rural locations to 0.81 ppm at urban sites. The carbon content of T. recurvata, which averaged 42.9 ± 0.34% (dry weight), was not influenced by the surrounding CO concentration. In contrast, the δ13C depended on the sites where the plants were collected. For example, the values were -13.2‰ in rural areas and as low as -17.5‰ in an urban site. Indeed, the isotopic values had a positive linear relationship with the atmospheric CO concentrations. Given the close relationship observed between the isotopic composition of T. recurvata with the CO concentrations in the Valley of Mexico, the δ13C values can be useful for the detection of atmospheric carbonaceous emissions.

Oil Bioremediation in a Tropical Contaminated Soil Using a Reactor.

This research was implemented in the Colombian Amazon forest area; to assess the effect of Tween-80® surfactant in the degradation of the Total Petroleum Hydrocarbons (TPH) in bioremediation treatments under aerobic conditions in the laboratory and pilot-scale. One control treatment, Natural Attenuation (AT) and four biostimulation treatments with leonardite with four different dosages of Tween-80® were proposed. The efficacy of organic stimulators and nonionic surfactant in soil microbiota was studied at laboratory and pilot scales, the latter in a passive aeration reactor. The test that presented a better performance was carried out with a Convective Flow Reactor (CFR) at pilot-scale. The results showed that bioremediation strategies improved the natural degradation process; the best outcomes were obtained in a treatment that includes Leonardite and Tween-80® (1.5 g/L) with 52% TPH degradation in 80 days (d).Tween-80® produced an effect in TPH solubility, and increased the production of CO2 in distinctive bioremediation treatments in both periods. The kinetics of CO2 production showed that the system required a periodic addition of a co-substrate as well as an increase of soil microbiota through the addition of compost (pilot scale). In this stage more than 76% of contaminant was degraded in 60d.

Comparative histological studies on properties of polysaccharides secreted by vomeronasal glands of eight Laurasiatheria species.

Most mammalian species have a vomeronasal organ that detects specific chemical substances, such as pheromones. Mucous fluid covering the vomeronasal sensory epithelium is secreted by vomeronasal glands, and the properties of these fluids have been suggested to be involved in chemical detection. Histological studies using periodic acid-Schiff (PAS) and Alcian blue pH 2.5 (AB) stains, which respectively detect natural and acidic polysaccharides, have suggested variations in the nature of the vomeronasal glands among species. Here, we investigated the responsivity of the vomeronasal glands to PAS and AB stains in eight Laurasiatheria species. All species studied herein possessed vomeronasal glands that stained positive for PAS, like other many reported species. The vomeronasal glands of dogs and minks - like rodents, were AB-negative, whereas those of cows, goats, sika deer, musk shrews and two bat species were positive. Considering the present findings and previous reports, the vomeronasal glands in most of Laurasiatheria species appear to be fundamentally abundant in acidic polysaccharides, whereas those in carnivores essentially contains neutral polysaccharides.

No country for new seeds: food and environmental security implications of Mexico's intended ban on GM crops.

An intended generalized ban on the "introduction and use of transgenic seeds" has been announced by the Mexican government, which, unlike the other agricultural programs under this administration, lacks a budget and rules of operation. In this policy brief we consider scenarios of implementing such an intended ban, de-regulating the use of genetically modified crops, or an intermediate scenario under the existing biosafety regulations. We recommend maintaining the status quo given its potential contributions to food and environmental security, in addition to a better economic outlook. However, a greater impulse needs to be given by the federal government to foment the domestic development of GM crops that are pertinent for Mexican agri-food needs, in addition to funding the development and implementation of various agro-ecological practices that increase biodiversity in food production units.

Modeling the Resonance Shifts Due to Coupling Between HTS Coils in NMR Probes.

Nuclear magnetic resonance (NMR) probes using thin-film HTS coils offer high sensitivity and are particularly suitable for small-sample applications. Typically, HTS probes are optimized for the detection of multiple nuclei and require several coils to be located within a small volume near the sample. Coupling between the coils shifts coil resonances and complicates coil trimming when tuning HTS probes. We have modeled the magnetic coupling between the coils of a 1.5-mm all-HTS NMR probe with 13C, 1H, and 2H channels. By measuring the magnetic coupling coefficients between individual coils, we solve the general coupling matrix given by KVL for six coupled resonators. Our results indicate that required trims can be accurately predicted by applying single coil trimming simulations to this magnetic coupling model. Use of the magnetic coupling model significantly improves the efficiency of tuning HTS probes.

Drying protocol does not alter plant δ13C and δ15N: a baseline survey for ecological studies.

Drying protocols might alter the isotopic signatures of plant samples given that high temperatures can volatilize various organic compounds or delay the halting of physiological processes at lower drying temperatures. We thus evaluated the effect of four drying protocols on the carbon and nitrogen isotopic signatures for 23 species of plants. In particular, leaves were either freeze-dried, placed in a herbarium drying stove (ca. 50°C), in a gravity convection oven (80°C), or microwaved (900 W) in 2-minute pulses, until constant weight. For each species, neither treatment led to significantly different δ13C values, which ranged from -31.7 to -12.4‰. The δ15N values of 21 of the species considered were not affected by the drying protocols, ranging from -11.6 to -8.8‰. For Tillandsia makoyana, significant differences were observed between the freeze dried and the microwaved samples and between the freeze dried samples and those dried at 50°C for Macroptilium gibbosifolium.

Characterization of nitrogen deposition in a megalopolis by means of atmospheric biomonitors.

An increase of nitrogen deposition resulting from human activities is not only a major threat for global biodiversity, but also for human health, especially in highly populated regions. It is thus important and in some instances legally mandated to monitor reactive nitrogen species in the atmosphere. The utilization of widely distributed biological species suitable for biomonitoring may be a good alternative. We assessed the suitability of an ensemble of atmospheric biomonitors of nitrogen deposition by means of an extensive sampling of a lichen, two mosses, and a bromeliad throughout the Valley of Mexico, whose population reaches 30 million, and subsequent measurements of nitrogen metabolism parameters. In all cases we found significant responses of nitrogen content, C:N ratio and the δ15N to season and site. In turn, the δ15N for the mosses responded linearly to the wet deposition. Also, the nitrogen content (R2 = 0.7), the C:N ratio (R2 = 0.6), and δ15N (R2 = 0.5) for the bromeliad had a linear response to NOx. However, the bromeliad was not found in sites with NOx concentrations exceeding 80 ppb, apparently of as a consequence of excess nitrogen. These biomonitors can be utilized in tandem to determine the status of atmospheric nitrogenous pollution in regions without monitoring networks for avoiding health problems for ecosystems and humans.