Hallux Flexion Deformity Secondary to Fibula Harvesting in a 10-Year-Old Patient With Neurofibromatosis.

Hallux interphalangeal joint (IPJ) flexion contracture is an uncommon deformity with various underlying causes, including trauma, neurological disorders, and connective tissue pathologies. We present a unique case of a 10-year-old female patient with neurofibromatosis type 1 (NF1) and a history of fibula transposition surgery, resulting in a hallux IPJ flexion contracture. We believe that the loss of the proximal fibular attachment of the extensor hallucis longus (EHL) following fibula harvesting resulted in EHL weakness and unopposed flexor hallucis longus (FHL) pull that eventually led to the contracture. The patient underwent various diagnostic assessments, ruling out other potential causes of the deformity. This case emphasizes the importance of considering previous surgical interventions when encountering flexion contractures of the toes.

Key role of plankton species and nutrients on biomagnification of PAHs in the micro-food chain: A case study in plateau reservoirs of Guizhou, China.

There is considerable inconsistency in results pertaining to the biomagnification of PAHs in aquatic systems. Zooplankton specifically play an important role controlling the fate and distribution of organic contaminants up the food chain, particularly in large plateau reservoirs. However, it remains largely unknown how secondary factors affect the magnification of organic compounds in zooplankton. The present study assessed plankton species and nutrients affecting the trophic transfer of PAHs through the micro-food chain in plateau reservoirs, Guizhou Province China. Results show soluble ∑PAHs range from 99.9 - 147.3 ng L-1, and concentrations of ∑PAHs in zooplankton range from 1003.2 - 22441.3, with a mean of 4460.7 ng g-1 dw. Trophic magnification factors (TMFs) > 1 show biomagnifications of PAHs from phytoplankton to zooplankton. The main mechanisms for trophic magnification > 1 are 1) small Copepoda, Cladocera and Rotifera are prey for larger N. schmackeri and P. tunguidus, and 2) the δ15N and TLs of zooplankton are increasing with the increasing nutrients TN, NO3- and CODMn. As a result, log PAHs concentrations in zooplankton are positively correlated with the trophic levels (TLs) of zooplankton, and log BAFs of the PAHs in zooplankton are increasing with increasing TLs and log Kow. Temperature further enhances TMFs and biomagnifications of PAHs as noted by temperature related reductions in δ15N. There are also available soluble PAHs in the water column which are assimilated with increasing phytoplankton biomass within the taxa groups, diatoms, dinoflagellates and chlorophytes. Notable TMFs of PAHs in zooplankton in Guizhou plateau reservoirs are not significantly affected by phytoplankton and zooplankton biomass dilutions. The present study demonstrates the important roles of species selection, nutrients and temperature in the environmental fate of PAHs in freshwaters.

Validation of the familial chylomicronaemia syndrome (FCS) score in an ethnically diverse cohort from UK FCS registry: Implications for diagnosis and differentiation from multifactorial chylomicronaemia syndrome (MCS).

BACKGROUND AND AIMS: Prognosis and management differ between familial chylomicronaemia syndrome (FCS), a rare autosomal recessive disorder, and multifactorial chylomicronaemia syndrome (MCS) or severe mixed hyperlipidaemia. A clinical scoring tool to differentiate these conditions has been devised but not been validated in other populations. The objective of this study was to validate this score in the UK population and identify any additional factors that might improve it. METHODS: A retrospective validation study was conducted using data from 151 patients comprising 75 FCS and 76 MCS patients. All participants had undergone genetic testing for genes implicated in FCS. Validation was performed by standard methods. Additional variables were identified from clinical data by logistic regression analysis. RESULTS: At the recommended FCS score threshold ≥10 points, the sensitivity and specificity of the score in the UK population were 96% and 75%, respectively. The receiver operating characteristic (ROC) curve analysis yielded an area under the curve (AUC) of 0.88 (95% CI 0.83-0.94, p < 0.001). This study identified non-European (predominantly South Asian) ethnicity, parental consanguinity, body mass index (BMI) < 25 kg/m2, and recurrent pancreatitis as additional positive predictors, while BMI >30 kg/m2 was found to be a negative predictor for FCS. However, inclusion of additional FCS predictors had no significant impact on performance of standard FCS score. CONCLUSIONS: Our study validates the FCS score in the UK population to distinguish FCS from MCS. While additional FCS predictors were identified, they did not improve further the score diagnostic performance.

Bioadsorption, bioaccumulation and biodegradation of antibiotics by algae and their association with algal physiological state and antibiotic physicochemical properties.

Bioadsorption, bioaccumulation and biodegradation processes in algae, play an important role in the biomagnification of antibiotics, or other organic pollutants, in aquatic food chains. In this study, the bioadsorption, bioaccumulation and biodegradation of norfloxacin [NFX], sulfamethazine [SMZ] and roxithromycin [RTM]) is investigated using a series of culture experiments. Chlorella vulgaris was exposed to these antibiotics with incubation periods of 24, 72, 120 and 168 h. Results show the bioadsorption concentration of antibiotics in extracellular matter increases with increasing alkaline phosphatase activity (AKP/ALP). The bioaccumulation concentrations of NFX, SMZ and RTM within cells significantly increase after early exposure, and subsequently decrease. There is a significant positive antibiotics correlation to superoxide dismutase (SOD), the photosynthetic electron transport rate (ETR) and maximum fluorescence after dark adaptation (Fv/Fm), while showing a negative correlation to malondialdehyde (MDA). The biodegradation percentages (Pb) of NFX, SMZ and RTM range from 39.3 - 97.2, 41.3 - 90.5, and 9.3 - 99.9, respectively, and significantly increase with increasing Fv/Fm, density and chlorophyll-a. The accumulation of antibiotics in extracellular and intracellular substances of C. vulgaris is affected by antibiotic biodegradation processes associated with cell physiological state. The results succinctly explain relationships between algal growth during antibiotics exposure and the bioadsorption and bioaccumulation of these antibiotics in cell walls and cell matter. The findings draw an insightful understanding of the accumulation of antibiotics in algae and provide a scientific basis for the better utilization of algae treatment technology in antibiotic contaminated wastewaters. Under low dose exposures, the biomagnification of antibiotics in algae is affected by bioadsorption, bioaccumulation and biodegradation.

Untapped resource: the simulation-based healthcare environment as a means to study human stress.

The effects of 'stress' within the healthcare professions are wide-reaching, not least of all within the field of simulation-based healthcare education. Whilst this popular method of experiential learning offers a 'safe space' for participants to develop their skillset, it also has a more surreptitious action; namely, the incubation of simulation-related stress. Currently, research concerning the complex relationship between stress, learning, and performance is ambiguous, leaving fertile ground for simulationists to debate what level of stress is appropriate for an optimised educational experience. In this narrative review, we examine the human response to stress and outline the various methods that have been used by researchers to measure stress in a quantifiable and standardised way. We then provide a brief overview of simulation-based healthcare education before describing why stress responses have been of interest to healthcare educationalists for some time. Finally, we outline how simulation education environments might provide an ideal environment for studying the human response to stress generally, with ramifications extending beyond the field of medical education.

Combustion conditions influence toxicity of flame-generated soot to ocular (ARPE-19) cells.

Soot is a prevalent aerosol found both indoors and outdoors that has several sources, such as natural (e.g., wildfires), civilian (e.g., cooking), or military (e.g., burn pit operation). Additionally, within the sources, factors that influence the physicochemical properties of the soot include combustion temperature, oxygen availability, and fuel type. Being able to reproduce soot in the laboratory and systematically assess its toxicity is important in the pursuit of elucidating pathologies associated with its exposure. Of the organs of interest, we targeted the eye given the scant attention received. Yet, air pollution constituents such as soot have been linked to diseases such as age-related macular degeneration and proliferative vitreoretinopathy. We developed a bench-scale system to synthesize different types of soot, that is, soot with a systematically varied physical attributes or chemical composition. We used common analytical techniques to probe such properties, and used statistical analyses to correlate them with toxicity in vitro using ARPE-19 cells. Within the range of flame conditions studied, we find that soot toxicity increases with increasing oxygen concentration in fuel-rich premixed flames, and weakly increases with decreasing flame temperature. Additionally, soot particles produced in premixed flames are generally smaller in size, exhibit a lesser fractal structure, and are considerably more toxic to ARPE-19 cells than soot particles produced in non-premixed flames.

Safety and Immunogenicity of a Recombinant Two-Component SARS-CoV-2 Protein Vaccine: Randomized, Double-Blind, Placebo-Controlled Phase I and Phase II Studies.

INTRODUCTION: ReCOV is a recombinant protein vaccine that aims to induce cross-neutralization against SARS-CoV-2 variants. The phase I and phase II studies were conducted in New Zealand and the Philippines, respectively, for ReCOV primary series. METHODS: Both studies were randomized, double-blind, placebo-controlled designed among COVID-19 vaccine-naïve healthy adults who received two doses of study vaccination with a 21-day interval. In phase I, 100 younger (15-55 years) and older (56-80 years) subjects were 4:1 randomized to receive ReCOV (20 µg or 40 µg) or placebo. In the phase II study, 347 subjects (≥ 18 years) were 2:1 randomized to receive 40 µg ReCOV or placebo. Subjects that received ReCOV were followed up for 6 months after the second dosing. The safety outcomes included solicited and unsolicited AEs, SAEs, and AESIs. The immunogenicity outcomes were live-virus neutralizing antibody (NAb) against prototype, while pseudovirus NAbs against several SARS-CoV-2 variants were included in phase II as well. RESULTS: No related SAE, AESI, or AE leading to early discontinuation were reported. The AE incidences were higher in ReCOV groups than placebo group in phase I while they were similar between study groups in phase II. The majority of solicited AEs were mild or moderate with median duration of 1.0-4.0 days. The common (≥ 10%) solicited AEs in phase I were injection site reactions, headache, pyrexia, fatigue, and myalgia, and common reported (≥ 5%) ones in phase II included injection site pain, headache, and pyrexia. Robust neutralizing activities against the prototype were observed in ReCOV groups, peaking at 14 days post the second dosing: in phase I, the GMTs for 20 µg and 40 µg ReCOV groups were 1643.2 IU/mL (95% CI 1188.5, 2271.9) and 1289.2 IU/mL (95% CI 868.3, 1914.1) in younger adults, and 1122.3 IU/mL (95% CI 722.6, 1743.1) and 680.3 IU/mL (95% CI 440.2, 1051.4) in older adults, respectively, while in the ReCOV group of phase II, the GMTs for subjects with seronegative and seropositive status at baseline were 3741.0 IU/mL (95% CI 3113.4, 4495.0) and 6138.3 IU/mL (95% CI 5255.1, 7169.9), respectively. In phase II, substantial levels of pseudovirus NAbs against SARS-CoV-2 variants were demonstrated; the peak GMTs for prototype, Omicron BA.2, and BA.4/5 were 8857, 4441, and 2644, and 15,667.3, 7334.3, and 4478.8 among seronegative and seropositive subjects, respectively. The neutralization persisted till 6 months post the second dosing, with only 2.5- to 5.2-fold declines for Omicron variants. CONCLUSIONS: Two doses of 20 µg and 40 µg ReCOV are safe and immunogenic against SARS-CoV-2 prototype. The cross-neutralizing activities against Omicron variants support ReCOV advance to late-stage clinical trials. TRIAL REGISTRATION: Phase I study, clinicaltrials.gov NCT04818801; phase II study, clinicaltrials.gov NCT05084989.

Severe Hypertriglyceridaemia and Chylomicronaemia Syndrome-Causes, Clinical Presentation, and Therapeutic Options.

We have reviewed the genetic basis of chylomicronaemia, the difference between monogenic and polygenic hypertriglyceridaemia, its effects on pancreatic, cardiovascular, and microvascular complications, and current and potential future pharmacotherapies. Severe hypertriglyceridaemia (TG > 10 mmol/L or 1000 mg/dL) is rare with a prevalence of <1%. It has a complex genetic basis. In some individuals, the inheritance of a single rare variant with a large effect size leads to severe hypertriglyceridaemia and fasting chylomicronaemia of monogenic origin, termed as familial chylomicronaemia syndrome (FCS). Alternatively, the accumulation of multiple low-effect variants causes polygenic hypertriglyceridaemia, which increases the tendency to develop fasting chylomicronaemia in presence of acquired factors, termed as multifactorial chylomicronaemia syndrome (MCS). FCS is an autosomal recessive disease characterized by a pathogenic variant of the lipoprotein lipase (LPL) gene or one of its regulators. The risk of pancreatic complications and associated morbidity and mortality are higher in FCS than in MCS. FCS has a more favourable cardiometabolic profile and a low prevalence of atherosclerotic cardiovascular disease (ASCVD) compared to MCS. The cornerstone of the management of severe hypertriglyceridaemia is a very-low-fat diet. FCS does not respond to traditional lipid-lowering therapies. Several novel pharmacotherapeutic agents are in various phases of development. Data on the correlation between genotype and phenotype in FCS are scarce. Further research to investigate the impact of individual gene variants on the natural history of the disease, and its link with ASCVD, microvascular disease, and acute or recurrent pancreatitis, is warranted. Volanesorsen reduces triglyceride concentration and frequency of pancreatitis effectively in patients with FCS and MCS. Several other therapeutic agents are in development. Understanding the natural history of FCS and MCS is necessary to rationalise healthcare resources and decide when to deploy these high-cost low-volume therapeutic agents.

A randomized, double-blind, 3-arm, parallel study assessing the pharmacokinetics, safety, tolerability and immunogenicity of AVT04, an ustekinumab candidate biosimilar, in healthy adults.

BACKGROUND: This study assessed pharmacokinetic (PK) similarity, safety, and immunogenicity of AVT04, a candidate biosimilar, compared with reference product (RP) ustekinumab (EU-approved and US-licensed Stelara®). METHODS: Healthy subjects (N = 298) were randomized 1:1:1 to receive one 45 mg dose of AVT04, EU-RP, or US-RP. The primary PK parameters were Cmax and AUC0-inf. PK similarity was demonstrated if the 90% confidence intervals (CI) for the ratio of geometric means were all contained within the prespecified margins of 80% and 125%. Additional PK parameters, including AUC0-t, were also assessed. Safety and immunogenicity were also assessed until Day 92. RESULTS: After pre-specified protein content normalization, the 90% CI for the ratio of geometric means for primary PK parameters were all contained within the pre-specified bioequivalence margins of 80% and 125%, supporting demonstration of PK similarity between AVT04 and both EU- and US-RP. Secondary PK parameters supported the analysis. Safety and immunogenicity profiles were comparable across all three treatment arms, although the study was not powered to detect small differences in these parameters. CONCLUSION: Results supported a demonstration of PK similarity between candidate biosimilar AVT04, US-RP and EU-RP. Similar safety and immunogenicity were also shown.Clinical trial registration: www.clinicaltrials.gov identifier is NCT04744363.

Long-term effects of volanesorsen on triglycerides and pancreatitis in patients with familial chylomicronaemia syndrome (FCS) in the UK Early Access to Medicines Scheme (EAMS).

BACKGROUND AND AIMS: The VOL4002 study assessed the efficacy and safety of volanesorsen in 22 adults with genetically confirmed familial chylomicronaemia syndrome (FCS) treated in the UK Early Access to Medicines Scheme (EAMS), with ("prior exposure") or without ("treatment naive") previous treatment in the APPROACH and/or APPROACH-OLE volanesorsen phase 3 studies. METHODS: Data collection focused on triglyceride (TG) levels, platelet counts and pancreatitis events. Pancreatitis incidence during volanesorsen treatment was compared against the 5-year period preceding volanesorsen exposure. Volanesorsen 285 mg was self-administered subcutaneously once every 2 weeks. RESULTS: Individual patient volanesorsen exposure ranged from 6 to 51 months (total cumulative exposure, 589 months). Among treatment-naive patients (n = 12), volanesorsen treatment resulted in an averaged median 52% reduction (-10.6 mmol/L) from baseline (26.4 mmol/L) in TG levels at 3 months, which were maintained through time points over 15 months of treatment (47%-55% reductions). Similarly, prior-exposure patients (n = 10) experienced a 51% reduction (-17.8 mmol/L) from pre-treatment baseline (28.0 mmol/L), with reductions of 10%-38% over 21 months of treatment. A comparison of pancreatitis event rates found a 74% reduction from the 5-year period before (one event/2.8 years) and during (one event/11.0 years) volanesorsen treatment. Platelet declines were consistent with observations in phase 3 clinical trials. No patient recorded a platelet count <50 × 109/L. CONCLUSIONS: This longitudinal study supports the efficacy of volanesorsen in patients with FCS for lowering TG levels over treatment periods up to 51 months with no apparent safety signals related to increased duration of exposure.

The varved succession of Crawford Lake, Milton, Ontario, Canada as a candidate Global boundary Stratotype Section and Point for the Anthropocene series.

An annually laminated succession in Crawford Lake, Ontario, Canada is proposed for the Global boundary Stratotype Section and Point (GSSP) to define the Anthropocene as a series/epoch with a base dated at 1950 CE. Varve couplets of organic matter capped by calcite precipitated each summer in alkaline surface waters reflect environmental change at global to local scales. Spheroidal carbonaceous particles and nitrogen isotopes record an increase in fossil fuel combustion in the early 1950s, coinciding with early fallout from nuclear and thermonuclear testing - 239+240Pu and 14C:12C, the latter more than compensating for the effects of old carbon in this dolomitic basin. Rapid industrial expansion in the North American Great Lakes region led to enhanced leaching of terrigenous elements by acid precipitation during the Great Acceleration, and calcite precipitation was reduced, producing thin calcite laminae around the GSSP that is marked by a sharp decline in elm pollen (Dutch Elm disease). The lack of bioturbation in well-oxygenated bottom waters, supported by the absence of fossil pigments from obligately anaerobic purple sulfur bacteria, is attributed to elevated salinities and high alkalinity below the chemocline. This aerobic depositional environment, highly unusual in a meromictic lake, inhibits the mobilization of Pu, the proposed primary stratigraphic guide for the Anthropocene.

Are foot and ankle corticosteroid injections safe during the COVID-19 pandemic? A single center prospective observational study.

BACKGROUND: Intra-articular corticosteroid injections (ICSI) are commonly used in orthopedic practice. Due to concerns about their immunosuppressive effects, we conducted a prospective observational audit, to monitor for COVID-19 infection amongst a group of foot and ankle patients who received an ICSI during the pandemic. PATIENTS AND METHODS: Included were 68 patients (25 males - 43 females, mean age 59.1 years, SD 15.0, range 19 - 90 years) who received a fluoroscopy-guided ICSI within a two-month period during the pandemic. The American Society of Anaesthesiologists (ASA) grade was I in 35 % of patients, II in 58 % and III in 7 %. 16 % of patients had black, Asian or minority ethnic (BAME) background. The dose of methylprednisolone injected was 20 mg for 28 % of the patients, 40 mg for 29 % and 80 mg for 43 %. RESULTS: All patients were available for follow up at one and four weeks post-injection. None reported COVID-19 infection symptoms within this period. The only complication was a flare-up of joint pain. CONCLUSION: Our study showed that the risk of COVID-19 infection to patients receiving foot or ankle ICSI is low. The limitations of this work must be considered, but our findings support the judicious use of corticosteroid injections during the current crisis.

Annual-scale assessment of mid-20th century anthropogenic impacts on the algal ecology of Crawford Lake, Ontario, Canada.

Meromictic Crawford Lake, located in SW Ontario, Canada is characterized by varved sediments, making it suitable for high-resolution paleoecological studies. Freeze cores, the only coring method available that reliably preserves the fragile laminations representative of seasonal deposition in the lake, were used to document siliceous diatom and chrysophyte community structure at an annual resolution from 1930-1990CE. Stratigraphically constrained cluster analysis identified major assemblage changes that are believed to have been caused by local, regional and possibly global anthropogenic impacts. The assemblage changes within the siliceous algae are attributed to regional weather and increased industrial emissions and related effects of acid deposition on the lake's catchment associated with the Great Acceleration -the massive economic, industrial, and demographic expansion beginning in the mid-20th century. Observed increases in spheroidal carbonaceous particles (SCPs) in varved lake sediment dating to the early 1950s record rapidly expanding steel production without emission controls around 30 km upwind of the lake. The findings reported here reflect major changes in earth systems that the Anthropocene Working Group recommends for a proposed epoch to be termed the Anthropocene, providing support for the laminated sediments from Crawford Lake as a potential Global boundary Stratotype Section and Point (GSSP).

Functional connectivity signatures of major depressive disorder: machine learning analysis of two multicenter neuroimaging studies.

The promise of machine learning has fueled the hope for developing diagnostic tools for psychiatry. Initial studies showed high accuracy for the identification of major depressive disorder (MDD) with resting-state connectivity, but progress has been hampered by the absence of large datasets. Here we used regular machine learning and advanced deep learning algorithms to differentiate patients with MDD from healthy controls and identify neurophysiological signatures of depression in two of the largest resting-state datasets for MDD. We obtained resting-state functional magnetic resonance imaging data from the REST-meta-MDD (N = 2338) and PsyMRI (N = 1039) consortia. Classification of functional connectivity matrices was done using support vector machines (SVM) and graph convolutional neural networks (GCN), and performance was evaluated using 5-fold cross-validation. Features were visualized using GCN-Explainer, an ablation study and univariate t-testing. The results showed a mean classification accuracy of 61% for MDD versus controls. Mean accuracy for classifying (non-)medicated subgroups was 62%. Sex classification accuracy was substantially better across datasets (73-81%). Visualization of the results showed that classifications were driven by stronger thalamic connections in both datasets, while nearly all other connections were weaker with small univariate effect sizes. These results suggest that whole brain resting-state connectivity is a reliable though poor biomarker for MDD, presumably due to disease heterogeneity as further supported by the higher accuracy for sex classification using the same methods. Deep learning revealed thalamic hyperconnectivity as a prominent neurophysiological signature of depression in both multicenter studies, which may guide the development of biomarkers in future studies.

Neural suppression in odor recognition memory.

Little is known about the neural basis of lower- and higher-order olfactory functions such as odor memory, compared with other sensory systems. The aim of this study was to explore neural networks and correlates associated with 3 functions: passive smelling (PS), odor encoding (OE), and in particular odor recognition memory (ORM). Twenty-six healthy participants were examined using functional magnetic resonance imaging conducted across 3 sessions, one for each function. Independent component analysis revealed a difference between sessions where a distinct ORM component incorporating hippocampus and posterior cingulate showed delayed triggering dissociated from odor stimulation and recognition. By contrasting Hit for ORM (target odors correctly recognized as old) and a combination of PS and detected odors from OE, we found significantly lower activations in amygdala, piriform cortex, insula, thalamus, and the inferior parietal lobule. Region of interest analysis including anterior insula, posterior cingulate gyrus, dentate gyrus, left middle frontal gyrus, amygdala, and piriform cortex demonstrated that Hit were associated with lower activations compared with other memory responses. In summary, our findings suggest that successful recognition of familiar odors (odor familiarity) is associated with neural suppression in the abovementioned regions of interest. Additionally, network including the hippocampus and posterior cingulate is engaged in a postrecognition process. This process may be related to incidental encoding of less familiar and more novel odors (odor novelty) and should be subject for future research.

Biological testing during acute psychological stress: A hindrance or an opportunity?

All humans deal with acute psychological stress periodically. Some individuals are affected by needle phobia in which a heightened sense of arousal is precipitated by venepuncture. Acute psychological stress invokes a range of physiological changes including activation of the sympathetic-adrenal-medullary and hypothalamic-pituitary-adrenal axes. In this review article, we first examine the human response to acute stress. We then provide an overview of how psychological stress in a subject is likely to be a source of pre-analytical variability for certain measurands, and the major biochemical markers that have been studied in research aiming to quantify stress. As such, we highlight how stress can be a hindrance to the accurate interpretation of certain laboratory results (particularly cortisol, prolactin, metanephrines and growth hormone), and point out the role that biochemical analysis might play in future studies looking at the effects of stress on human behaviour.

Bioaccumulation and emission of organophosphate esters in plants affecting the atmosphere's phosphorus cycle.

The imbalance of atmospheric, terrestrial and aquatic phosphorus budgets remains a research conundrum and global concern. In this work, the uptake, distribution, bioaccumulation and emission of organophosphate esters (OPEs) by clove trees (Syzygium aromaticum), lemon trees (Citrus limon) and cape jasmine trees (Gardenia jasminoides var. fortuniana) was investigated as conduits for phosphorus transfer or sinks and sources. The objective was to assess the role OPEs in soils play as atmospheric phosphorus sources through plant bioaccumulation and emission. Results demonstrated OPEs in experimental soil plots ranging from 0.01 to 81.0 ng g-1 dry weight, were absorbed and transported through plants to the atmosphere. The total emission of OPEs varied greatly from 0.2 to 588.9 pg g-1 L-1 h-1, with a mean of 47.6 pg g-1 L-1 h-1. There was a negative linear relationship between the concentrations of total phosphorus and four OPEs, tri-iso-butyl phosphate, tri-n-butyl phosphate, tris (2-chloroisopropyl) phosphate and tripentyl phosphate. Trimethyl phosphate levels were positively correlated with total nitrogen, and the concentrations of tri-iso-butyl phosphate, tri-n-butyl phosphate, tris (2-chloroisopropyl) phosphate and tripentyl phosphate decreased along with available potassium in leaves after 72 h. There was a significantly positive linear relationship between higher emission concentrations of OPEs and the emission factor of OPEs concentration (F = 4.2, P = 0.002), with lower emissions of OPEs and the bioaccumulation of OPEs in leaves (F = 4.8, P = 0.004). OPEs releases to the atmosphere were enriched in aerosols, and participate in atmospheric chemical reactions like photolysis, thereby affecting the phosphorus balance and cycling in the atmosphere.

Microbial community day-to-day dynamics during a spring algal bloom event in a tributary of Three Gorges Reservoir.

The microbial food-loop is critical to energy flow in aquatic food webs. We tested the hypothesis that species composition and relative abundance in a microbial community would be modified by the development of toxic algal blooms either by enhanced carbon production or toxicity. This study tracked the response of the microbial community with respect to composition and relative abundance during a 7-day algal bloom event in the Three Gorges Reservoir in May 2018. Chlorophyll a biomass, microscopic identification and cell counting of algae and algal abundance (ind. L-1) and carbon, nutrient concentrations (total phosphorus and nitrogen, dissolved total phosphorus and nitrogen), and DNA high throughput sequencing were measured daily. Algal density (1.2 × 109 ind. L-1) and Chlorophyll a (219 µg L-1) peaked on May 20th-21st, when the phytoplankton community was dominated by Chlorella spp. and Microcystis spp. The concentrations of both dissolved total nitrogen and phosphorus declined during the bloom period. Based on DNA high throughput sequencing data, the relative abundance of eukaryotic phytoplankton, microzooplankton (20-200 µm), mesozooplankton (>200 µm), and fungal communities varied day by day while the prokaryotic community revealed a more consistent structure. Enhanced carbon production during the bloom was closely associated with increased heterotrophic microbial composition in both the prokaryotic and eukaryotic communities. A storm event, however, that caused surface cooling and deep mixing of the water column greatly modified the composition and relative abundance of species in the microbial loop. The high temporal variability and dynamics observed in this study suggest that many factors, and not just algal blooms, were interacting to determine the composition and relative abundance of species of the microbial loop.