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We read with interest the recent editorial, “The Hennepin Ketamine Study,” by Dr. Samuel Stratton commenting on the research ethics, methodology, and the current public controversy surrounding this study.1 As researchers and investigators of this study, we strongly agree that prospective clinical research in the prehospital environment is necessary to advance the science of Emergency Medical Services (EMS) and emergency medicine. We also agree that accomplishing this is challenging as the prehospital environment often encounters patient populations who cannot provide meaningful informed consent due to their emergent conditions. To ensure that fellow emergency medicine researchers understand the facts of our work so they may plan future studies, and to address some of the questions and concerns in Dr. Stratton’s editorial, the lay press, and in social media,2 we would like to call attention to some inaccuracies in Dr. Stratton’s editorial, and to the lay media stories on which it appears to be based.
Ho JD, Cole JB, Klein LR, Olives TD, Driver BE, Moore JC, Nystrom PC, Arens AM, Simpson NS, Hick JL, Chavez RA, Lynch WL, Miner JR. The Hennepin Ketamine Study investigators’ reply. Prehosp Disaster Med. 2019;34(2):111–113
In the current study, phage-exposed mimotopes as targets against tegumentary leishmaniasis (TL) were selected by means of bio-panning cycles employing sera of TL patients and healthy subjects, besides the immune stimulation of peripheral blood mononuclear cells (PBMCs) collected from untreated and treated TL patients and healthy subjects. The clones were evaluated regarding their specific interferon-γ (IFN-γ) and interleukin-4 (IL-4) production in the in vitro cultures, and selectivity and specificity values were calculated, and those presenting the best results were selected for the in vivo experiments. Two clones, namely A4 and A8, were identified and used in immunization protocols from BALB/c mice to protect against Leishmania amazonensis infection. Results showed a polarized Th1 response generated after vaccination, being based on significantly higher levels of IFN-γ, IL-2, IL-12, tumour necrosis factor-α (TNF-α) and granulocyte-macrophage colony-stimulating factor (GM-CSF); which were associated with lower production of specific IL-4, IL-10 and immunoglobulin G1 (IgG1) antibodies. Vaccinated mice presented significant reductions in the parasite load in the infected tissue and distinct organs, when compared with controls. In conclusion, we presented a strategy to identify new mimotopes able to induce Th1 response in PBMCs from TL patients and healthy subjects, and that were successfully used to protect against L. amazonensis infection.
Collagen associated with bone samples is frequently used for radiocarbon (14C) dating of bones recovered from archaeological sites. However, submersion and exposure to moisture favors the degradation of collagen, which leads to difficulty in reliably dating bones from tropical, humid, or previously submerged archaeological sites. In this paper, we characterized the preservation state of a series of bones, through parameters such as %C, %N, C/N ratio, and collagen recovery. We performed 14C analyses of three collagen fractions obtained through the pretreatment steps (total, ultrafiltered, and insoluble collagen) in order to link the preservation state and the reproducibility of 14C values obtained from the three fractions. Collagen ultrafiltration resulted in a decrease of C/N ratio, although collagen yield was reduced. When two or three collagen fractions were obtained, ages were reproducible and consistent with expected values, according to archaeological or hydrogeological criteria. The pretreatment steps were monitored by infrared spectroscopy in order to analyze the collagen fractions at the molecular level. The presence of collagen in the total and insoluble fractions was confirmed. Since many of the Mexican samples had poor ultrafiltered collagen yield (<3%) or nonexistent yield, our results show that if additional contextual information is carefully considered, the remnant collagen in the total and insoluble fraction can be dated, especially from sites where no other datable fraction exists.
The Nevado de Toluca is a stratovolcano located in the southwest of the Toluca Valley in central Mexico. At a height of around 4200 m there are two crater lakes: El Sol and La Luna. Since Precolumbian times, people in the surrounding valleys carried out rituals and deposited offerings into the lakes. After the Spanish conquest, these rituals were kept alive clandestinely. Currently, reminiscent of Mesoamerican rituals subsist. Due to the long duration of the ritual at the Nevado de Toluca, it is important to date the materials recovered in the underwater and terrestrial archaeological explorations. This article proposes a chronology of Prehispanic ritual activities performed in the Nevado de Toluca based on the characterization and radiocarbon (14C) dating performed to materials from the volcano’s lakes.
Multiwall carbon nanotubes (MWCNTs) are utilized to resolve low coupling coefficient issue by dispersing MWCNTs in poly(vinylidene fluoride) matrix to create stress reinforcing network, dispersant, and electron conducting functions for barium titanate (BT) nanoparticles. Various BT and MWCNT percentages of nanocomposite film are fabricated by FDM three-dimensional (3D) printing which can simplify the fabrication process as well as lower cost and design flexibility. Increasing MWCNTs and BT particles gradually increase piezoelectric coefficient (d31) by 0.13 pC/N with 0.4 wt%-MWCNTs/18 wt%-BT. These results provide not only a technique to print piezoelectric nanocomposites but also unique materials combination for sensor application.
To examine the causal directionality in the relationship between food insecurity and emotional well-being among US-based populations.
Systematic literature review from January 2006 to July 2016 using MEDLINE (PubMed), PsychInfo, Web of Science and CINHAL. Inclusion criteria were: written in English; examined a longitudinal association between food insecurity and emotional well-being.
Children and adults.
Twelve out of 4161 peer-reviewed articles met inclusion criteria. Three articles examined the effect of emotional well-being on food insecurity, five studies examined the effect of food insecurity on emotional well-being, and four studies examined a bidirectional relationship. Most studies (83 %) reported a positive relationship between negative emotional well-being and food insecurity over time.
Findings suggest a bidirectional association whereby food insecurity increases the risk of poor emotional health, and poor emotional health increases the risk of food insecurity. Better-constructed studies are needed to follow cohorts at risk for both food insecurity and poor emotional health to further understand the mediators and moderators of the relationships. Intervention studies designed to mitigate or reverse risks are also needed to determine best evidence for practice and policy.
The origins of the large Classic and Postclassic urban centres of Central Mexico remain poorly understood. Archaeological investigations at the Formative site of Tlalancaleca in Puebla (Mexico) provide the first detailed study of a large-scale urban centre of that period. Preliminary results suggest that the growth and development of this particular site may have influenced the subsequent growth of Teotihuacan itself. This study explores how urbanisation can be identified archaeologically by tracing the expansion of population and the emergence of monumental architecture.
Air pollution in Mexico City, which has more than 22 million inhabitants, continues to be one of the main environmental issues. Aerosol samples (PM10) collected in Mexico City and the city of Cuernavaca (a clean reference site) have been characterized using different techniques. This multifaceted approach addresses the source apportionment of the carbonaceous matter in PM10, as well as the airborne elements and ions. Accelerator mass spectrometry (AMS) radiocarbon analysis of total carbon, X-ray fluorescence (XRF), and ion chromatography were performed on aerosols collected at three sites in Mexico City and one site in Cuernavaca, during 2 months of the cold-dry season (November–December) in 2012. New results obtained for Mexico City are compared with previous reports. Average levels of PM10 were higher in Mexico City sites (43.3–60.8 μg/m3) than in Cuernavaca (32.2 μg/m3). According to the material balance, PM10 collected in Mexico City had a lower contribution of crustal material (31.2–36.8%) than Cuernavaca (46.9%). Average contributions of particulate carbonaceous matter to PM10 were similar in both cities, but much higher contributions of mineral salts, trace elements, and ions were observed in Mexico City in comparison to Cuernavaca. Total organic carbon (OC) and elemental carbon (EC) contents were higher in aerosols from Mexico City than those from Cuernavaca. The temporal variation results showed that within all locations studied the OC concentration was high compared to the EC. Results from a theoretical calculation of fossil carbon (FC) and biogenic carbon (BC) concentrations showed that FC and BC levels depend on the site: at Mexico City sites, FC was equal or higher than BC. At Cuernavaca, BC was always higher than FC.
In 2003, flooding occurred in the Ciudadela (Citadel) of Teotihuacan and saltpeter began to damage the Temple of the Feathered Serpent. Work done to solve this problem led to one of the most important archaeological discoveries made in this site in recent years: an intact tunnel sealed for more than a thousand years. The project created to study the tunnel was named Tlalocan or Path to the Underworld. More than 60,000 objects have been recovered after years of exploration and removing huge amounts of soil and stones. This paper presents the first results of accelerator mass spectrometry (AMS) radiocarbon dating performed on some of those materials recovered from the tunnel. With these findings, in combination with the archaeological data, based on stratigraphy and ceramic typology, a chronology of several events is proposed concerning the construction phases and ceremonial use, as well as partial and definitive closures of the tunnel. Every closure was accompanied by a deliberate and structured deposition of offerings and ritual refuse along the tunnel. The range of ages that covers the Bayesian calibration of samples collected along the tunnel is around 115 yr, from AD 125 to 240. Material collected at the surface of the chamber located at the end of the tunnel and under the pyramid gave ages in the interval between AD 400 and 534. All samples analyzed fall within the interval of time that covers the period of occupation of Teotihuacan.
We have assembled a new sample of some of the most FIR-luminous galaxies in the Universe and have imaged them in 1.1 mm dust emission and measured their redshifts 1 < z < 4 via CO emission lines using the 32-m Large Millimeter Telescope / Gran Telescopio Milimétrico (LMT/GTM). Our sample of 31 submm galaxies (SMGs), culled from the Planck and Herschel all-sky surveys, includes 14 of the 21 most luminous galaxies known, with LFIR > 1014L⊙ and SFR > 104M⊙/yr. These extreme inferred luminosities – and multiple / extended 1.1 mm images – imply that most or all are strongly gravitationally lensed, with typical magnification μ ~ 10 × . The gravitational lensing provides two significant benefits: (1) it boosts the S/N, and (2) it allows investigation of star formation and gas processes on sub-kpc scales.
The present work is a study on alkali activation of Mexican blast furnace slag, using sodium silicate. The aim is to produce an optimal specimen, homogeneous without carbonation, and with small fraction of crystalline phases, similar to CSH, which provide mechanical properties suitable to use in the construction industry. The samples were prepared using sodium silicate activator solutions with modulus (SiO2/Na2O) of 1.25, 1.5, and 1.75. The weight percentage of Na2O in the activator solutions was added at 4, 6 and 8% relative to the slag weight. The prepared samples were stored in sealed molds, at room temperature (20°C), during 7 days. The X-ray diffraction has revealed the presence of an amorphous phase, semi crystalline clinotobermorite phase and signals of calcium carbonate for the samples of 4 and 6 % of Na2O; in contrast with the 8% Na2O, where the latter signals almost disappeared. The specimen selected as optimal was prepared with an activator concentration of 8% of Na2O /Slag, and SiO2/Na2O of 1.25. A specimen under these optimal conditions was prepared with accelerated curing (40°C, humidity, 48 hours), and a compressive strength test was attained, with an average value of 52 MPa at 3 days.
In this paper, the formation of Langmuir-Blodgett films of poly(p-acryloylaminophenylmethylphosphonic) acid polymers, with general formula (C10H12NPO4)n are reported. The Langmuir-Blodgett (LB) technique was used for building ordered nanostructures in molecular assemblies of these polymers, which were able to form stable films. At the air-water interface, these polymers (with low and high molecular weight) formed Langmuir (L) monolayers, which were characterized by surface pressure versus molecular area (π-A) isotherms and Brewster´s Angle Microscopy (BAM). Using the LB method, molecular mono and multilayer films of these polymers were prepared and transferred onto glass substrates forming Z-type multilayers, with a transfer ratio close to unity. These LB films were characterized by Atomic Force Microscopy (AFM).
Stratigraphy, geochemistry and radiocarbon dating of a succession of sediment in the Santiaguillo Basin (central-northern Mexico) help reconstruct the millennial-scale dynamics of hydrological variability that occurred in the southern part of western subtropical North America since the late last glacial. Runoff was generally above average during the late last glacial from ~ 27 to 18 ka. Following this interval, runoff decreased and deposition of authigenic carbonate and aeolian transported sediment increased until ~ 4 ka. Heinrich 1 and 2, and Younger Dryas were intervals of reduced runoff and increased aeolian activity. The wetter climate of central-northern Mexico and arid conditions in north–northwestern Mexico during the late last glacial were probably related to formation of tropical cyclones in the eastern North Pacific during the autumn with restricted rainfall swaths and an absent/weaker North American Monsoon. Enhanced North American Monsoon and tropical cyclones with expanded rainfall swaths brought more summer and autumn precipitation to a broader region extending from the central-northern Mexico to the continental interiors of southwestern US during the early Holocene.
Six electric rays, Narcine leoparda, were caught off the coast of Manta, Ecuador between August 2013 and January 2014. These specimens represent the first record in Ecuadorian waters and the southernmost report in the eastern Pacific for the distribution of Narcine leoparda.