Non-invasive phrenic nerve stimulation to avoid ventilator-induced diaphragm dysfunction in critical care

Background: Diaphragm muscle atrophy during mechanical ventilation begins within 24 h and progresses rapidly with significant clinical consequences. Electrical stimulation of the phrenic nerves using invasive electrodes has shown promise in maintaining diaphragm condition by inducing intermittent diaphragm muscle contraction. However, the widespread application of these methods may be limited by their risks as well as the technical and environmental requirements of placement and care. Non-invasive stimulation would offer a valuable alternative method to maintain diaphragm health while overcoming these limitations. Methods: We applied non-invasive electrical stimulation to the phrenic nerve in the neck in healthy volunteers. Respiratory pressure and flow, diaphragm electromyography and mechanomyography, and ultrasound visualization were used to assess the diaphragmatic response to stimulation. The electrode positions and stimulation parameters were systematically varied in order to investigate the influence of these parameters on the ability to induce diaphragm contraction with non-invasive stimulation. Results: We demonstrate that non-invasive capture of the phrenic nerve is feasible using surface electrodes without the application of pressure, and characterize the stimulation parameters required to achieve therapeutic diaphragm contractions in healthy volunteers. We show that an optimal electrode position for phrenic nerve capture can be identified and that this position does not vary as head orientation is changed. The stimulation parameters required to produce a diaphragm response at this site are characterized and we show that burst stimulation above the activation threshold reliably produces diaphragm contractions sufficient to drive an inspired volume of over 600 ml, indicating the ability to produce significant diaphragmatic work using non-invasive stimulation. Conclusion: This opens the possibility of non-invasive systems, requiring minimal specialist skills to set up, for maintaining diaphragm function in the intensive care setting

Survey and Molecular Characterization of Sarcocystidae protozoa in Wild Cricetid Rodents from Central and Southern Chile

In Chile, studies of parasites from the family Sarcocystidae (Apicomplexa) have mostly been related to domestic animals. We aimed to assess the presence of Sarcocystidae taxa in cricetid rodents from Central and Southern Chile. We studied 207 rodents, encompassing six species, from 13 localities. We isolated DNA from tissue samples, amplified the Sarcocystidae 18S rRNA gene with polymerase chain reaction, and performed phylogenetic analyses using maximum likelihood and Bayesian inferences. In addition, we examined blood smears and performed histological studies in organs from Sarcocystidae DNA-positive animals. Three specimens were DNA-positive and three genotypes were retrieved and named: Sarcocystis sp. P61, related to Sarcocystis strixi, was detected in two Abrothrix olivacea. Toxoplasmatinae gen. sp. P99 was retrieved from those same two specimens, and was related to Toxoplasma and other genera, although it branched independently. Besnoitia sp. R34 was detected in one Abrothrix hirta, and was clustered with congeneric species associated with rodents. No protozoa were found during microscopic studies; thus, it was not possible to confirm parasitic interactions rather than accidental encounters. However, the close relatedness of the retrieved genotypes to parasites of rodents supports the hypothesis of host–parasite associations. All three genotypes are suggested as potential new taxa, including a putative new genus.This research was funded by the ANID Programa Becas Doctorado Nacional under grant numbers 2019–21190078, 2020–21200182, and 2022-21220118; and Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT) under grant number 11170294.Peer reviewe

An exploratory study into the role and interplay of intrinsic and extrinsic cues in Australian consumers’ evaluations of fish.

This study explores the role and interplay of intrinsic and extrinsic cues when evaluating fish quality and in shaping consumers' attitudes toward fish consumption. A sensory analysis of nine different fish including five variants of barramundi was conducted to determine how consumers evaluated the fish on intrinsic cues. Focus groups were then conducted to explore the impact of extrinsic cues on attitudes and purchase intentions. While the sensory analysis revealed distinct differences between barramundi variants on intrinsic cues (notably taste), the focus groups revealed that, as a brand, barramundi is perceived much more favourably and consistently. Consumers used extrinsic cues, particularly country of origin, as surrogate indicators of quality. Aquaculture producers need to ensure intrinsic product quality and consistency, as while consumers use the extrinsic cue of "Australian grown" as a surrogate indicator of quality, as their familiarity and confidence with seafood grows, this overreliance on extrinsic cues may diminish

Kinetics of algor mortis. First steps for estimating time since death in animals

The time elapsed from death until the moment the corpse equals its temperature to ambient temperature is known as "Early Post Mortem Interval", and during this period the decrease in body temperature -algor mortis- is a useful routine measure to estimate postmortem interval (IPM) in human forensics. Early IPM for humans is 24 hours on average, but there is no information regarding animals that allow the use of algor mortis as an estimator of IPM. In this study, the core body and ambient temperature were measured continuously in 50 dead laboratory rats. Results showed that, on average, early IPM was 11 hours 14 minutes, ranging between 8 hours and 32 minutes and 17 hours with 7 minutes. An equation that estimates the IPM in rats was also obtained, minimizing residuals. This is the first experimental study aimed to obtain parameters to estimate the postmortem interval from algor mortis in animals

A simple model accounting for the uptake, transport, and deposition of wind-eroded mineral particles in the hyperarid coastal Atacama Desert of northern Chile

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Inter-annual variability of southerly winds in a coastal area of the Atacama Desert : implications for the export of aeolian sediments to the adjacent marine environment

The analysis of the aeolian content of marine cores collected off the coast of the Atacama Desert (Mejillones Bay, Chile) suggests that marine sediments can record inter-annual to inter-decadal variations in the regional southerly winds responsible for particle entrainment at the surface of the nearby desert. However, the establishment of a simple and direct correlation between the sediment and wind records is complicated by the difference of time scales between the erosion and accumulation processes. The aim of this work is to: (i) assess the inter-annual variability of the surface winds responsible for the sand movements; and (ii) determine whether the integration over periods of several months completely smoothes the rapid changes in characteristics of the transported and deposited aeolian material. To accomplish this aim, 14 years of 10 m hourly wind speed, measured at the Cerro Moreno (Antofagasta) Airport between 1991 and 2003 and at the Orica Station between 2000 and 2004, were analyzed. For each year, the wind speed statistical distribution can be represented by a combination of two to three Weibull functions. Winds of the lowest Weibull mode are too weak to move the sand grains at the surface of the pampa; this is not the case for the intermediate mode and especially for the highest speed mode which are able to erode the arid surface and transport particles to the bay. In each individual year of the period of study, the highest speed mode only accounted for a limited number of strong erosion events. Quantitative analysis of the distribution of the friction velocities and of their impact on erosion using a saltation model suggests that, although all wind speeds above threshold produce erosion events, values around 0.45 m sec-1 contribute less to the erosion flux. This gap allows separation of the erosion events into low and high saltation modes. The correlation (r = 0.997) between the importance of the third Weibull mode and the extent of higher rate saltation indicates that the inter-annual variability of the erosion at the surface of the pampa, as well as the transport of coarse particles (>100 mu m), are directly related to inter-annual variations in the prevalence of the strongest winds. Finally, a transport and deposition model is used to assess the possible impact of the wind inter-annual variability on the deposition flux of mineral particles in the bay. The results suggest that inter-annual differences in the wind speed distributions have a quantifiable effect on the intensity and size-distribution of this deposition flux. This observation suggests that a detailed analysis of the sediment cores collected from the bay could be used for reconstructing the inter-annual variability of past winds

Electroca rdiographic abnormalities in cocaine base paste consumers of Metropolitan Santiago Alteraciones electrocardiogrâficas en consumidores de pasta base de cocaína del Area Metropolitana

Background: The adverse effects of cocaine use mainly occur in the heart and central nervous system. Aim: To study the effects of cocaine base paste consumption on the cardiovascular system. Subjects and methods: Thirty five chronic cocaine base paste consumers, 26 male, aged 15 to 43 years old, were studied. A clinical assessment and a resting EKG were performed. Results were compared with those of 82 healthy controls. Results: Sixty percent of cocaine consumers had EKG abnormalities, compared with 43% of controls. Forty one percent of cocaine users and 33% of controls had a prolonged QTc. Likewise, 36% of cocaine users and 46% of controls had an incomplete right bundle branch block. Among cocaine users, an active nodal rhythm, an ischemic and a QS anteroseptal image were observed. Conclusions: A slightly higher frequency of EKG abnormalities were observed in chronic cocaine users, when compared with healthy controls

Inter-annual variability of southerly winds in a coastal area of the Atacama Desert: implications for the export of aeolian sediments to the adjacent marine environment

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Antioxidant Compound Adsorption in Polyvinylpolypyrrolidone from Chilean Carménère, Cabernet Sauvignon, and Merlot Grape Pomaces as Potential By-Products

Grape pomace (GP) is a by-product resulting from the winemaking process and its potential use as a source of bioactive compounds is well known. The GP bioactive compounds can be retained in the well-known polyvinylpolypyrrolidone (PVPP), industrially used in the clarification and stabilization of wine and other drinks. Thus, the polyphenolic compounds (PC) from the Chilean Carménère, Cabernet Sauvignon, and Merlot GP were extracted, and their compositions and antioxidant capacities (ORAC-FL) were determined. In addition, the retention capacity of the PC on PVPP (PC-PVPP) was evaluated. The bioactivities of GP extracts and PC-PVPP were estimated by the agar plate inhibition assay against pathogenic microorganisms. Results showed a high amount of TPC and antioxidant capacity in the three ethanolic GPs extracts. Anthocyanins, flavan-3-ol, and flavonols were the most abundant compounds in the GP extract, with retentions between 70 and 99% on PVPP. The GP extracts showed inhibition activity against B. cereus and P. syringae pv. actinidiae but the GP-PVPP had no antimicrobial activity. The high affinity of the identified PCs from GPs on PVPP polymer could allow the design of new processes and by-products for the food or cosmeceutical industry, promoting a circular economy by reducing and reusing wastes (GPs and PVPP) and organic solvents

Antifungal and antibacterial activities of Araucaria araucana (Mol.) K. Koch Heartwood lignans

Five lignans (secoisolariciresinol, pinoresinol, eudesmin, lariciresinol, and lariciresinol-4-methyl ether) were isolated from an MeOH extract from Araucaria araucana (Mol.) K. Koch wood for the first time in this species and their structures determined with spectroscopic methods. The antimicrobial activities of these compounds were determined for the bacteria Citrobacter sp., Bacillus subtilis, Escherichia coli, Micrococcus luteus, Staphylococcus aureus, and Pseudomonas aeruginosa, and for the white rooting and staining fungi Mucor miehei, Paecilomyces variotii, Ceratocystis pilifera, Trametes versicolor, and Penicillium notatum, and in addition, the MeOH extract was evaluated against Aspergillus niger, Candida albicans, Fusarium mondiforme, F sporotrichum and Trichophyton mentagrophytes. The most sensitive bacteria against pinoresinol were the Gram-positive. However, secoisolariciresinol exhibited a significant antifungal activity on fungi of white rooting and wood staining and this compound completely inhibited the mycelial growth of T versicolor and C, pilifera at 300 and 400 mu g per disc, respectively, whereas pinoresinol showed a moderate inhibitory activity. On the other hand, the MeOH extract had the highest activity against rooting and staining and pathogenic fungi as well as T versicolor, Fusarium spp. and Trichophyton mentagrophytes, inhibiting completely the growth at 400 mu g per disc