Canopy level fog occurrence in a tropical lowland forest of French Guiana as a prerequisite for high epiphyte diversity

Fog frequency and the meteorological processes leading to fog formation have never been studied in depth in tropical lowland forest areas. This study provides detailed evidence of frequent fog occurrence in lowland valleys of central French Guiana. Fog frequency showed a clear diurnal course, with a maximum before sunrise; average fog duration was 4.6 h. The diurnal course of visibility was positively correlated with the diurnal course of humidity in the above-canopy air. Fog persistence correlated significantly with atmospheric parameters during the dry season, but not during the rainy season. The main trigger of fog development in the lowland forest seemed to be precipitation, leading to higher soil moisture, greater evapotranspiration and, thus, higher water content of air. An increasing temperature difference between valley and hill sites after sunset, together with more frequent down-slope winds during nights with long fog periods, points at some influence of katabatic flows. The frequent occurrence of fog in the valleys correlated with significantly higher epiphyte diversities in valley forests as compared to hill forests, and supported the occurrence of the hitherto undescribed, epiphyte-rich “tropical lowland cloud forest” (LCF) in the valleys. The higher epiphyte diversity in LCF coincided with significantly higher relative air humidity in LCF than in hill forest. The ecological benefits of fog for the epiphytes in LCF are surplus of moisture and delayed onset of the stress period, particularly in the dry season.     

Impact of high-fat and high-carbohydrate diets on liver metabolism studied in a rat model with a systems biology approach

The aim of the present study was to investigate the use of an integrated metabolomics and proteomics approach in the elucidation of diet-induced effects on hepatic metabolism in a rat model. Nuclear magnetic resonance (NMR)-based metabolomics of liver extracts revealed a pronounced effect of a high-fat diet on the hepatic betaine content, whereas a carbohydrate-rich diet induced increases in hepatic glucose. In addition, the metabolomic investigations revealed that the high-fat diet was associated with increased hepatic lipid levels, which was not evident with the carbohydrate-rich diet. The proteomic investigations revealed strong high-fat diet effects on the expression of 186 proteins in the liver including malate dehydrogenase. Comparison of malate dehydrogenase expression determined by proteomics and NMR metabolite profiles revealed correlations between malate dehydrogenase and lactate, glucose, and glutamine/glutamate signals, thereby demonstrating a diet-induced regulation that was evident at both proteomic and metabolomic levels.     

Effects of N‐source,light intensity and temperature on nitrogen metabolism of bahiagrass

Under greenhouse conditions, a study was made on the effects of nitrogen (N) source (N)O₃ or NH₄), mode of application (single vs. split) and nitrification inhibition on the N‐uptake and metabolism, of bahiagrass.

Variations in light and temperature in the greenhouse affected the N‐metabolism of bahiagrass plants. Nitrate fed plants had nitrate reductase activity (NRA) pattern different from that of NH₄‐fed plants. Amino‐N accumulation patterns were similar for plants under both N‐sources, although amino‐N levels in leaves of NH₄‐fed plants were much smaller than that of NO₃ plants. Nitrate accumulation in leaves showed inverse trend to that of roots in plants fed both NO₃ or NH₄. To the sharp peaks in NO₃ levels in roots due to increases in light and temperature corresponds a sharp decrease of its levels in leaves.

For both both NO₃ or NH₄ treatments, soluble‐N accumulated most in the rhizomes of bahiagrass plants, whereas protein N accumulated most in leaves, suggesting that rhizomes had a buffering effect on the NO₃ fluxes to leaves. This presumably resulted in a lag in the NRA response of the NO₃‐fed plants to increases in light and temperature.     

Effect of head and tail rope-assisted recovery of horses after elective and emergency surgery under general anaesthesia

The recovery phase is a critical period during equine anaesthesia. In an attempt to reduce the risk of recovery, several recovery systems, including head and tail ropes, have been developed over time. However, the clinical safety and efficacy of these systems have not been compared to a nonassisted group in a larger study. The objective of this comparative, retrospective, nonrandomised single-centre study was to determine whether the risk of developing fatal and nonfatal complications after general anaesthesia is reduced in horses assisted with head and tail ropes during recovery compared with horses recovering unassisted. Included were all horses undergoing general anaesthesia at the Large Animal Hospital, University of Copenhagen, Denmark, from 2010 to 2019. Analysed data included age, body mass, American Society of Anesthesiologists grade of physical status (ASA score), type of surgery and anaesthetic duration. Complications were divided into none, fatal and nonfatal. Logistic regression was performed to analyse the risk and predictors of fatal and nonfatal complications using the built-in R function ‘step’. Tukey’s honest significance difference test was applied to determine significance, set at P<0.05, within the categorical variables of the reduced models. The study included 1252 horses: 662 recovered with assistance (group A) and 590 without (group NA). Overall recovery-associated mortality was 1.4%: 0.6% in group A and 2.2% in group NA. Both emergency abdominal surgery (P = 0.004) and duration of surgery (P = 0.0001) affected the risk of fatal complications negatively. Assisted recovery (P = 0.02) significantly reduced the risk of fatal complications after emergency abdominal surgery. The limitation of the study was a lack of randomisation and potentially a larger proportion of sedation among assisted horses. It was concluded that emergency abdominal surgery and duration of anaesthesia are significant risk factors for fatal complications during recovery. Head and tail rope-assisted recovery is a significant factor of reducing fatal complications during recovery after emergency abdominal surgery.     

Serum Krebs von den Lungen-6 for Predicting the Severity of COVID-19 Lung Injury: A Systematic Review and Meta-Analysis

Introduction:Lung injury is common in COVID-19 patients. The severity of lung injury appears to be reflected in serum KL-6, a glycoprotein expressed on type II alveolar epithelium. This study aims to assess the role of serum KL-6 in reflecting the severity of lung injury in COVID-19 patients. Methods:A systematic search was conducted in Scopus, PubMed, Wiley Online Library, and ProQuest. Articles were screened based on several eligibility criteria and assessed for study quality using NOS. Results:This systematic review included four studies involving a total of 151 adult COVID-19 patients. Pooled analysis revealed that serum KL-6 was significantly higher in severe patients (SMD = 1.16; 95% CI = 0.69–1.63) with moderately high pooled sensitivity (79%; 95% CI = 61–91%) and specificity (86%; 95% CI = 72–95%). Conclusion:High serum KL-6 may depict more severe lung injury in COVID-19 patients with moderately high sensitivity and specificity. Key Words: Biomarker, COVID-19, Infectious disease, Krebs von den Lungen-6, Lung injury