Intensive Sampling Research Articles

Unveiling the organic chemical composition and sources of organic carbon in PM2.5 at an urban site in Greater Cairo (Egypt): A comprehensive analysis of primary and secondary compounds

This work presents an exhaustive chemical characterization of the organic fraction of fine particulate matter (PM2.5) collected at an urban site in the Greater Cairo Area, Egypt, one of the most polluted megacities in the world. An intensive 2-month sampling campaign was conducted at an urban site in Giza (Dokki), from November 26, 2019, to January 28, 2020. Daily (24-h integrated) PM2.5 filter samples were then analyzed for their carbonaceous (OC, EC) and organic fractions including primary (n-alkanes, phthalates, fatty acids, polycyclic aromatic hydrocarbons, hopanes, sugars, and sugar alcohols) and secondary (isoprene and β-caryophyllene oxidation products, and dicarboxylic acids) compounds. Average organic (OC) and elemental carbon (EC) concentrations were 17.8 ± 6.6 μg/m3 and 4.4 ± 1.5 μg/m3, respectively. Biomass burning was confirmed by high daily concentration levels of levoglucosan, mannosan, and galactosan (sum equals to 288 ng/m3). Road traffic was also highlighted by the relative abundance of tetracosane and a carbon preference index close to unity as well as by the concentration ratios of PAHs and hopanes. Moreover, phthalates were identified for the first time in Cairo with high concentrations (654 ng/m3) that might be attributable to open waste burning activities. Fatty acids and sugars were also investigated and assigned to cooking activities and primary biogenic sources, respectively. The average concentration of isoprene and β-caryophyllene oxidation products were 0.89 ± 0.83 ng/m3, and 0.01 ± 0.02 ng/m3, respectively. These low values are expected since no pine trees or even forests exist in Egypt. The macrotracer approach was employed alongside Monte Carlo simulation to identify sources of primary OC and evaluate the uncertainties associated with source attribution and OC reconstruction. The findings revealed a strong contribution from cooking (31% of observed OC) and biomass burning (18%), with median reconstructed OC levels showing significant uncertainty (64%) as expected.

Predicting lake chlorophyll from stream phosphorus concentrations

AbstractExcess nutrient loads from streams drive primary production in downstream lakes, and managing these loads is key to achieving desired conditions in lakes. However, quantifying nutrient loads requires intensive sampling of both nutrient concentrations and streamflow. Total phosphorus measurements collected during routine stream monitoring are broadly available, but these data are thought to provide little information on annual nutrient loads because they are typically collected during low, baseflow conditions. Here, we demonstrate that these routine phosphorus measurements are correlated with annual nutrient loads. We also show that the average of these routine measurements of stream phosphorus within a watershed predict the average lake chlorophyll concentration in that same watershed. These relationships can then be used to set targets for stream phosphorus concentrations to achieve desired conditions in lakes.

Lower levels of household transmission of SARS-CoV-2 VOC Omicron compared to Wild-type: an interplay between transmissibility and immune status.

Knowledge of SARS-CoV-2 household transmission dynamics guides infection control and vaccination measures. This household cohort study prospectively assessed the impact of both the Omicron BA.2 variant and immunity on household transmission using dense saliva sampling and sequence analysis. Households consisting of a PCR-confirmed index and at least two household members were enrolled in March and April 2022 during the Omicron BA.2 wave in the Netherlands. SARS-CoV-2 PCR was performed on ten consecutive saliva samples. Serum-antibodies were measured at baseline and day 42. Household and per-person Secondary Attack Rate (SAR) were calculated to measure transmission. Whole genome sequencing was performed for phylogenetic analysis, followed by sensitivity analysis, to correct for multiple household introductions and index definition. Results were compared with the identical, early-pandemic, pre-immunisation predecessor study. Sixty-seven households were included, consisting of 241 individuals (median age 33.0 years (IQR 12.0-46.0)). Maximum household SAR was 59.7%, per-person SAR 41.5%. Paediatric index cases were more likely to transmit. Transmission was negatively affected by household members' immunity. Phylogenetic analysis showed multiple introductions in four households. Sensitivity analysis resulted in a minimal household SAR of 51.0% and per-person SAR of 28.5%. The Omicron BA.2 variant is highly transmissible within households. However, the transmission rate is lower compared to previous studies with other SARS-CoV-2 variants, highlighting the effect of immunity. Regardless of immune status, children have a crucial role in Omicron household transmission. Intensive sampling and phylogenetic analysis are beneficial for correctly calculating transmission rates, especially during periods of minimal behavioural restrictions.

Potential damage area detection of bridges based on single-temporal point cloud

Abstract With advantages of 3D representation, non-contact measurements and intensive sampling capability, it has been a research hotspot to detect the potential damage area of bridges with point cloud by TLS. However, TLS is commonly used to detect a potential damage area by comparing multi-temporal point cloud data, which limits the timeliness of bridge inspection. Therefore, aiming to accurately detect the potential damage areas of bridges with single-temporal point cloud, this paper proposes a normalized normal vector constrained coordinate transformation method. First, the distribution of sharp features is revealed in a single-temporal point cloud at potential damage areas, and a neighborhood growth method constrained by the normal distance is proposed to eliminate the sharp features in point cloud, which is prone to cause incorrect or missing curvature values from point cloud. Second, a normalized normal vector constrained coordinate transformation method is proposed to construct Gaussian curvature model, which can improve the accuracy of point cloud curvature and accurately detect the potential damage areas in bridges. At last, an evaluation criterion is proposed to quantify the bridge condition by integrating the characteristics of small-span concrete bridges in urban areas with actual damage data from the experimental bridges. The experimental results show that the proposed method can effectively detect the potential damage areas of the measured bridges.

Guidance Strategy and Fast Robustness Analysis for Space Debris Flyby

Envisioning the scenario of space debris inspection by orbital flyby, this paper investigates the guidance strategy and fast robustness analysis method considering the relative state constraints. First, the corrected state transition matrix is derived to predict and correct the perturbed relative state at the flyby moment. Based on the state transition matrix, a free-flight corridor model is established to characterize the maximum allowed magnitude of the deviation, which can quickly estimate the robustness of the trajectory under uncertainties and circumvent intensive numerical sampling. The corresponding optimization, with four norm-extreme constraints, can be solved by a proposed double-layer algorithm with proven convergence. Numerical simulations demonstrate that the guidance algorithm is effective, and the free-flight corridor can accurately and efficiently reflect the robustness of the nominal trajectory.

Intensive short-term sampling with long-term consequences: characterizing pollutant transport with implications for developing monitoring.

Riverine sampling of pollutants is commonly used to understand pollutants' transport pathways, relationships with hydrology, and overall presence in a waterbody. However, temporal gaps between sample collection introduce errors to these efforts, and guidance prescribing sampling frequency remains sparse. The magnitude of error often depends on a contaminant's transport mechanisms and local hydrologic conditions, making the creation of comprehensive sampling guidance difficult. This study analyzed a unique dataset that measured 18 analytes, including pesticides, nutrients, and pathogens, in three Iowa rivers for 90 consecutive days (May 4-August 1, 2000). This dataset provided a novel opportunity to relate pollutants to local hydrology and quantify errors associated with recurring sampling. Pesticide concentrations followed the spring flush phenomenon, where values were greatest during high streamflow in May and June but often depleted by July. Fecal coliform and total phosphorus (TP) also coincided with high flow, but unlike pesticides, their concentrations never diminished. Nitrate exhibited more complex behavior; concentrations were diluted during high flows and then increased as streamflow receded. Autocorrelations were significant for nitrate and atrazine in larger rivers but negligible for fecal coliform and TP. Loads were calculated for four pollutants with minimal non-detects (atrazine, fecal coliform, nitrate, and TP). We simulated intermittent sampling by selecting evenly spaced subsets of measured values to estimate loads, which were compared to the loads calculated using every daily sample to quantify error. This method typically overestimated nitrate loads but underestimated other pollutants, and errors often decreased in larger watersheds. Nitrate generally had the lowest error, while fecal coliform had the highest. We used these results to approximate the sampling frequency needed to bind errors within a certain threshold.

Comparison of microbiological loads of enteral products at two different ambient room temperatures.

Despite the high risk of bacterial contamination, no studies have been found that evaluate the optimal hanging time of open-system enteral sets under room temperature and intensive care conditions. This study aims to determine the differences in microbial loads of solutions taken from open-system enteral feeding sets hanging for 24 h under room temperature and intensive care conditions. This study is a descriptive type of research. The study sample consisted of a total of 40 samples, with 20 samples under room temperature (25.2-23.3°C) and 20 samples under intensive care conditions (21.1-24.2°C). A simple random sampling method was used for sample selection. The assessment of microbial quality was based on the US Food and Drug Administration online Bacteriological Analytical Manual. In this study, it was determined that 5% of the samples taken from intensive care and 15% of the samples taken at room temperature exceeded the accepted limit for aerobic mesophilic bacteria count. The count of catalase and coagulase-negative Staphylococcus spp was 5% in intensive care samples and 40% in room temperature samples. The total coliform count was not detected in intensive care samples but was 35% in room temperature samples. Escherichia coli was not detected in either group. Differences in microbial loads were observed when commercial enteral solutions were administered using open-system enteral feeding sets under room and intensive care conditions for 24 h. Therefore, large-scale studies are needed to determine the safe use of open-system enteral feeding sets under room temperature conditions.

Evaluation of Effective Half-Life and Its Impact on Time to Steady State for Oral MeltDose Tacrolimus (LCPT) in De Novo Kidney Transplant Recipients.

For extended-release drug formulations, effective half-life (t1/2eff) is a relevant pharmacokinetic parameter to inform dosing strategies and time to reach steady state. Tacrolimus, an immunosuppressant commonly used for the prophylaxis of organ rejection in transplant patients, is available as both immediate- and extended-release formulations. To the best of our knowledge, the t1/2eff of tacrolimus from these different formulations has not yet been assessed. The objective of this study was to characterize the t1/2eff and terminal half-life (t1/2z) of an extended-release once-daily tacrolimus formulation (LCPT) and twice-daily immediate-release tacrolimus (IR-Tac). A noncompartmental analysis of pharmacokinetic data obtained from a phase 2 study in de novo kidney transplant recipients receiving either LCPT or IR-Tac was conducted. Intensive blood sampling was performed on days 1, 7, and 14, and tacrolimus whole blood concentrations were measured using a validated liquid chromatography with tandem mass spectrometry method. T1/2eff was estimated using within-participant accumulation ratios. T1/2z was estimated by linear regression of the terminal phase of the concentration versus time profile. The median accumulation ratios of LCPT and IR-Tac on day 14 were 3.18 and 2.06, respectively.The median (interquartile range; IQR) t1/2eff for LCPT at day 14 of dosing was 48.4 (37.4-77.9) hours, whereas the t1/2z was 20.3 (17.6-22.9) hours. For IR-Tac, the median (IQR) t1/2eff and t1/2z on day 14 were 12.5 (8.8-23.0) hours and 12.2 (9.2-15.7) hours, respectively. Consistent with its prolonged release of tacrolimus, LCPT demonstrated a higher accumulation ratio and a longer t1/2eff compared with IR-Tac. These findings underscore the pharmacokinetic differences between different drug formulations of the same moiety and may help inform dose adjustments for LCPT in kidney transplantation.

Applying a Comprehensive Model for Single-Ring Infiltration: Assessment of Temporal Changes in Saturated Hydraulic Conductivity and Physical Soil Properties

Modeling agricultural systems, from the point of view of saving and optimizing water, is a challenging task, because it may require multiple soil physical and hydraulic measurements to investigate the entire crop cycle. The Beerkan method was proposed as a quick and easy approach to estimate the saturated soil hydraulic conductivity, Ks. In this study, a new complete three-dimensional model for Beerkan experiments recently proposed was used. It consists of thirteen different calculation approaches that differ in estimating the macroscopic capillary length, initial (θi) and saturated (θs) soil water contents, use transient or steady-state infiltration data, and different fitting methods to transient data. A steady-state version of the simplified method based on a Beerkan infiltration run (SSBI) was used as the benchmark. Measurements were carried out on five sampling dates during a single growing season (from November to June) in a long-term experiment in which two soil management systems were compared, i.e., minimum tillage (MT) and no tillage (NT). The objectives of this work were (i) to test the proposed new model and calculation approaches under real field conditions, (ii) investigate the impact of MT and NT on soil properties, and (iii) obtain information on the seasonal variability of Ks and other main soil physical properties (θi, soil bulk density, ρb, and water retention curve) under MT and NT. The results showed that the model always overestimated Ks compared to SSBI. Indeed, the estimated Ks differed by a factor of 11 when the most data demanding (A1) approach was considered by a factor of 4–8, depending on the transient or steady-state phase use, when A3 was considered and by a practically negligible factor of 1.0–1.9 with A4. A relatively higher seasonal variability was detected for θi at the MT than NT system. Under both MT and NT, ρb did not change between November and April but increased significantly until the end of the season. The selected calculation approaches provided substantially coherent information on Ks seasonal evolution. Regardless of the approach, the results showed a temporal stability of Ks at least from early April to June under NT; conversely, the MT system was, overall, more affected by temporal changes with a relative stability at the beginning and middle of the season. These findings suggest that a common sampling time for determining Ks could be set at early spring. Soil management affected the soil properties, because the NT system was significantly wetter and more compact than MT on four out of five dates. However, only NT showed a significantly increasing correlation between Ks and the modal pore diameter, suggesting the presence of a relatively smaller and better interconnected pore network in the no-tilled soil. This study confirms the need to test infiltration models under real field conditions to evaluate their pros and cons. The Beerkan method was effective for intensive soil sampling and accurate field investigations on the temporal variability of Ks.

The Dynamics of Trust and Trustworthiness Perceptions in a Government Agency: A Longitudinal Perspective

Although trust is widely recognized as key to effective public administration, little is known about trust dynamics, especially in typical governance relationships. We conducted an intensive longitudinal experience sampling study via a weekly survey of Florida residents’ ( N = 97) trust in and perceptions of the trustworthiness of the (US) National Hurricane Center over a 25-week hurricane season. We estimated two-level time series models to examine reciprocal relationships among four constructs: trust, ability, benevolence, and integrity. All four exhibited significant intraindividual variability such that participants demonstrated change in their ratings of the agency over time. Ability perceptions showed the greatest variability over the study duration. In line with classic models of trust, previous-week trustworthiness perceptions were significant predictors of subsequent trust. Our results also provide some support for self-reinforcing accounts of trust by demonstrating that previous-week trust predicted subsequent trustworthiness. Several of the one-week lagged relationships weakened substantially when tested with two-week lags, suggesting that trustworthiness is the stronger driver of trust. Overall, our results demonstrate that trust is not static, even in business-as-usual governance relationships. Results position perceptions of ability, benevolence, and integrity as partially responsible for changes in trust over time. Further, an exploratory analysis suggested that people who reported higher average integrity perceptions tended to have more stable trust. Thus, all the dimensions of trustworthiness serve as short-term levers for administrators seeking to positively manage relationships with the public, and integrity may be most critical for supporting steady levels of trust.

Linking summer nutrition to behavior and performance of black‐tailed deer

AbstractMany large‐herbivore populations are regulated at least in part by bottom‐up forces, and thus relationships between herbivores and their habitat are of fundamental importance to wildlife managers. Variation in nutritional resources—and how herbivores respond to that variation—influences rates of nutrient intake, which directly affect nutritional condition, pregnancy rates, timing of parturition, offspring birth mass, and survival. Accordingly, nutrition‐focused research holds great potential for uncovering the mechanisms that govern population performance of large herbivores and for assessing the nature and magnitude of bottom‐up limitations. We quantified relationships between the foodscape (i.e., spatiotemporal variation in forage quality and abundance) in southwestern Oregon, USA, and black‐tailed deer (Odocoileus hemionus columbianus) behavior and performance, with a focus on the influence of maternal nutrition on fawn survival. We hypothesized that black‐tailed deer performance (i.e., fawn birth mass and survival) is influenced by the availability of high‐quality forage during spring and summer and patterns of foodscape use exhibited by individual deer. From 2016–2023 we monitored movement and survival of adult female black‐tailed deer and their offspring. We also conducted intensive vegetation sampling and used generalized additive modeling to map the foodscape available to deer in spring and summer. Suitable forage biomass (i.e., maximum biomass of forage that together exceeded quality thresholds for supporting one fawn) was highly variable across space and time, and our top foodscape model explained 70% of the variation in suitable biomass (adjusted R2 = 0.70). We observed a strong, positive relationship between use of the foodscape by maternal females prior to parturition and fawn birth mass. Although maternal foodscape use after parturition did not influence the probability of fawn survival, survival increased with increasing birth mass. These results suggest that the effects of nutrition on fawn survival in our study system are indirectly mediated by maternal behavior (i.e., use of the foodscape) and the corresponding effects on birth mass of fawns. Our study adds to a growing body of literature supporting a fundamental link between foodscape use and population performance of large herbivores. Wildlife managers can use the dynamic models we developed to assess habitat quality and to make quantitative predictions about how different management actions (e.g., forest thinning) are likely to influence habitat quality and performance of black‐tailed deer.

Drug-Drug Interaction Between Dihydroartemisinin-Piperaquine and Sulfadoxine-Pyrimethamine During Malaria Chemoprevention in Pregnant Women.

Co-administration of dihydroartemisinin-piperaquine (DP) and sulfadoxine-pyrimethamine (SP) for intermittent preventive treatment of malaria in pregnancy (IPTp) may be superior in preventing adverse birth outcomes compared with either therapy alone, but potential drug-drug interactions require investigation. We conducted intensive and sparse pharmacokinetic (PK) studies in a subset of Ugandan women participating in a randomized controlled trial of monthly IPTp with SP vs. DP vs. DP + SP. Intensive PK sampling was performed from day 0 to 23 after dosing at 28 weeks gestation in 87 participants across treatment arms. Sparse sampling was performed on day 28 (trough) after dosing at 20 and 28 gestational weeks in additional 196 participants receiving SP vs. DP + SP. Intensive PK analysis demonstrated that compared with SP alone, co-administration of DP + SP was associated with lower maximal concentrations, the area under the concentration-time curves (AUC), and day 23 concentrations of sulfadoxine (25%, 25%, and 27%) and pyrimethamine (26%, 34%, and 32%) (P < 0.05 for all comparisons). Sparse PK results demonstrated participants co-administered DP + SP had lower trough concentrations after dosing at 20 and 28 gestational weeks for sulfadoxine (6%, P = 0.68 and 31%, P = 0.023, respectively) and pyrimethamine (18%, P = 0.032 and 33%, P < 0.001, respectively) compared with SP alone. Co-administration of DP + SP was associated with a 19% reduction in piperaquine AUC (P = 0.046), but no significant difference in other PK parameters compared with DP alone. In summary, co-administration of DP + SP was associated with significantly reduced SP exposure, with a greater magnitude during the third vs. second trimester. The clinical consequences of this interaction are yet unknown.

Protocol of clinical population pharmacokinetics/pharmacodynamics analysis of alkaloids from the leaves of alstonia scholaris in acute bronchitis patients

Objective: To validate whether orally administered Alkaloid Capsules from the leaves of Alstonia scholaris (CALAS) can improve the clinical indices of acute bronchitis and to investigate the alterations in the relationship between its composition and pharmacodynamic (PD) markers, thereby providing a clinical reference for the administration of this medication. Methods: This is a prospectively planned, blinded, placebo-controlled, parallel-grouped clinical trial with aggregated population pharmacokinetics/PD (PPK/PPD) data. A total of 55 subjects will be randomly allocated into four arms; specifically, 10 of the 55 subjects will be selected randomly for the placebo arm, and will be orally administered placebo (Tid), and 45 subjects will be randomly assigned to CALAS treatment groups (20 mg, 40 mg, and 80 mg Tid, at 15 subjects per group). The medication, presence of cough and phlegm, as well as body temperature of every subject will be recorded daily during treatment. About 3–4 blood samples will be collected from each subject at the following points for PPK/PPD parameters analysis: at pre-dose (0 h) and post-dose at 15 min, 40 min, 1 h, 1.5 h, 2 h, 3 h, 4 h, 6 h, 8 h, 12 h, 24 h, 30 h, and 48 h after last dosing. All the subjects will be subjected to a laboratory examination and efficacy evaluation on day 8. Discussion: A new integrating strategy to explore the relationship among drug components, action pathways, and clinical efficacy will be established through this study. We aim to explore the mechanism of action of CALAS in the treatment of acute bronchitis on the premise of definite active ingredients and reliable clinical efficacy. It is difficult to enrol patients in classical PK research because it adopts an intensive sampling method, and it cannot quantify the variability of PK parameters (Intra-individual variation, inter-individual variation and weekly variation). Moreover, the extrapolation and prediction of dosage regimens in different species and populations cannot be achieved. Therefore, the PPK/PPD method, which takes advantage of sparse data (3–5 time points sampling per patient), is adopted to determine the measurable pathological and physiological factors that can influence dose concentration to guide reasonable dose adjustment towards achieving optimal clinical effects.

Synthesis and characterization of molecularly imprinted polymer nanoparticles against porcine circovirus type 2 viral-like particles.

PCV2 is a significant epidemic agricultural pathogen that causes a variety of swine diseases. PCV2 infections have significant economic impact on the swine industry, making effective strategies for rapid detection of PCV2 in pigs essential. Herein, we report on the synthesis of the so-called nano-MIPs which can be utilized for molecular recognition of PCV2. The morphology and structure of nano-MIPs were characterized using scanning electron microscopy (SEM). Nano-MIPs are spherical with sizes around 120-150nm. Binding experiments demonstrate that the fluorescence intensity of PCV2 samples decreases proportionally to increasing the concentration of nano-MIPs due to quenching, while non-imprinted polymer nanoparticles (nano-NIPs) do not affect the signal. The Stern-Volmer constant of nano-MIPs binding to PCV2 was 1.3 × 10-3mL/µg, whereas nano-NIPs led to 7 × 10-5mL/µg, i.e., 1.8 orders of magnitude lower. The detection limit for binding MIP particles to PCV2 by fluorescence measurements is 47µg/mL. This affinity test allows for designing both direct and competitive quartz crystal microbalance (QCM) assays for PCV2 leading to QCM measurements. The QCM results show nano-MIPs binding to PCV2 immobilized on the sensor surface with appreciable reproducibility. QCM sensor characteristics reveal signal saturation above around 200µg/mL at a response of - 354Hz and an LOD of approximately 35µg/mL. Nano-MIPs also show selectivity factors of 2-5 for CSFV and PRRSV probably because the three viruses have similar diameters around 50nm.

Prevalence and abundance of plant-parasitic nematodes associated with corn (Zea mays L.) in Anuradhapura, Sri Lanka &amp;nbsp;

Plant parasitic nematodes (PPN) are important pests of corn (Zea mays L.) Globally, while corn production has recently expanded in Sri Lanka. The population abundance, distribution, and pathological effects of nematodes that adversely affect corn production in Sri Lanka are poorly understood. This study was conducted to identify the prevalence of major PPN genera, population abundance, and their reproduction associated with corn fields in the Anuradhapura district. Over 92% of the corn fields were positive for PPN from the fields sampled in February 2021. Major PPN genera identified were Pratylenchus (71.4%) Helicotylenchus (28.6%), Meloidogyne (21.4%), Criconemella (21.4%), and Hoplolaimus (35.7%). The mean population of the Pratylenchus was 2020 kg-1 of soil, which was above the threshold level (1000 Pratylenchus kg-1 of soil), while other genera were lower than the threshold. All genera, except Meloidogyne, were observed from the intensive sampling from the selected fields during the next cropping season from November 2021 (seedling stage) to February 2022 (harvesting stage). Pratylenchus abundance in all the fields was lower than the threshold at the seedling stage and it was 2 to 10 times higher during the harvesting stage, except in Kelenikawewa where the initial Pratylenchus population (1865 kg-1 of soil) was also above the threshold. According to our results, Pratylenchus have the potential to impact corn yield in Anuradhapura. Future field experiments will determine the impact of PPN on corn production in Sri Lanka.

Influence of NH3 flow rate on the photoelectric properties of high Al content p-AlGaN.

High Al content (60%) p-AlGaN with different NH3 flow rates was grown using metal-organic chemical vapor deposition (MOCVD), and changes in its photoelectric properties were studied using the Hall effect tester (Hall) and cathodoluminescence (CL) spectrometer. The results show that the film resistivity increases from 3.8 Ω·cm to 46.5 Ω·cm with increasing NH3 flow rate. The impurity peak intensity of p-AlGaN grown under high NH3 flow conditions is particularly high, indicating numerous point defects. The results of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) show a large number of Ga interstitial atoms (Gai) at the interface. As Gai acts as a donor, this may be the main reason for the increase in resistivity. And under high NH3 flow conditions, a lattice distortion and a high density of dislocation occur between p-AlGaN and p-GaN, which can lead to enhanced carrier scattering and decreased mobility. Additional validation via LED growth experiments indicates that the luminescence intensity of samples with low ammonia concentration increased by more than 13000 times.

The Addition of Transcriptomics to the Bead-Enabled Accelerated Monophasic Multi-Omics Method: A Step toward Universal Sample Preparation.

Omics-based measurements enable the study of biomolecules in a high-throughput fashion, leading to the characterization and quantification of biological systems. Multi-omics methods aim to incorporate several omics measurements for a more holistic approach, which is crucial for advancing our understanding of the diversity and redundancy of biological systems. Current multi-omics sample preparation methods have achieved proteomics, lipidomics, and metabolomics from individual samples; however, the bioinformatic tools currently available for interpreting data generated from these omics are limited. Alternately, transcriptomics has a wide arsenal of available bioinformatic tools offering intensive sample characterization but has yet to be incorporated into a unified, multi-omics sample preparation technique. Herein we describe the modified bead-enabled accelerated monophasic multi-omics (mBAMM) method, which incorporates RNA extraction for transcriptomics analysis. mBAMM was shown to enable RNA-seq without compromising the isolation of biomolecules for proteomics, lipidomics, and metabolomics. This methodology greatly improves sample characterization and represents a major innovation toward cohesive insights into biological systems.

Coarse bubble mixing in anoxic zone greatly stimulates nitrous oxide emissions from biological nitrogen removal process

The biological nitrogen removal process in wastewater treatment inevitably produces nitrous oxide (N2O), a potent greenhouse gas. Coarse bubble mixing is widely employed in wastewater treatment processes to mix anoxic tanks; however, its impacts on N2O emissions are rarely reported. This study investigates the effects of coarse bubble mixing on N2O emissions in a pilot-scale mainstream nitrite shunt reactor over a 50-day steady-state period. Online and offline N2O monitoring campaigns show that coarse bubble mixing in the anoxic zones significantly elevates N2O emissions, yielding an extremely high emission factor of 15.5 ± 3.5 %. Intensive sampling and isotopic analyses suggest that the elevated emissions are primarily due to the inhibition of the N2O denitrification process by oxygen in the anoxic phase introduced by coarse bubbling. Substituting coarse bubble mixing with submersible pump mixing resulted in a substantial reduction of N2O emissions, decreasing the emission factor by an order of magnitude to 1.2 ± 0.8 %. The findings reveal that a previously overlooked factor, coarse bubble mixing, can significantly stimulate N2O emissions. The use of coarse bubble mixing in anoxic tanks of biological nitrogen removal warrants caution.

Virulence of Puccinia coronata var avenae f. sp. avenae (oat crown rust) in Canada during 2016 to 2020 and comparison of extensive vs intensive sampling methods

Puccinia coronata var avenae f. sp. avenae (Pca), the causal fungus of crown rust of oats, is a significant threat to oat production in the eastern prairie region (Manitoba and eastern Saskatchewan; EPR), Ontario and Quebec (eastern Canada; EC), in Canada. Development of oat lines with effective resistance to Pca has been a priority for oat breeding programmes in Canada, and helped mitigate reductions in oat yield and quality. This requires knowledge of the virulence characteristics of the Pca population in Canada. Our objectives were to determine the incidence and severity of Pca in Canada, the presence and frequency of virulence and races in Pca populations and compare the traditional extensive sampling method (few isolates per field from many fields) to an intensive sampling method (many isolates per field from a few fields) for obtaining genetically diverse collections. The incidence and severity of crown rust of oat in Canada was lower in 2016 to 2020 than has been reported in previous years. Virulence to all the 24 Pc genes studied was observed over the 5 years in EC and the EPR. The most effective genes were Pc94, Pc98 and Pc101 in EC and Pc50, Pc96, Pc97 and Pc98 in the EPR. Approximately 81% of 424 races identified were of unique virulence phenotypes over the 5 years, indicating a highly variable Pca population in Canada. Races JTQG-91 and GTQG-91 were the most common races identified. Collections of Pca obtained using the extensive sampling method were observed to be more genetically diverse than collections obtained using the intensive sampling method in 2018 and 2020, but not in 2019.

Hexagonal Enhanced Porous GaN with Delayed Integrated Pulse Electrochemical (iPEC) Etching

This present study investigates the effect of time delay (Td) on the formation of porous GaN (P-GaN) using integrated pulse electrochemical (iPEC) etching. Porous GaN (P-GaN) was formed by etching an N-type GaN wafer with a 4% KOH electrolyte for 60 minutes under an ultraviolet (UV) lamp at a current density of 80 mA/cm2. A Td of 120 minutes was applied before electrochemically etching the P-GaN sample. The top view image of the field emission scanning electron microscopy (FESEM) revealed a significant difference when a Td was applied. A dense and uniform hexagonal P-GaN was obtained from the Td iPEC sample, while the non-Td sample exhibited a multi-layered hexagonal porous structure with unfinished pore-etched areas. Higher porosity and deeper pores were observed in the Td sample. Intense high-resolution X-ray diffraction (HR-XRD) peak intensity was observed in the Td iPEC sample with a lower full width half maximum (FWHM), indicating that the sample had better crystallinity. The Raman spectra of the sample anodized with a Td exhibited higher Raman peak intensity and a slight shift to a higher frequency concerning as-grown GaN, indicating better crystallinity and a tensile stress relaxation of 0.24 GPa. Post etching, a blue shift of the photoluminescence (PL) peak, from 364 nm (as-grown GaN) to 363 nm (P-GaN), was observed, and a small PL peak started to form around 385 nm compared to the as-grown GaN due to the relaxation of the tensile stress, which modified the bandgap. The PL peak intensity of the Td sample was higher than the non-Td sample, indicating that the porosity and uniformity allowed more light interaction with the material, resulting in more efficient photon absorption and emission. The results indicated that potentially efficient optoelectronics devices can be fabricated on a P-GaN using a combination of electroless and electrochemical etching of the GaN epitaxial layer.