Lower Average Concentrations Research Articles

Eocene to Early Miocene dinoflagellate cysts from the southern Gulf of Mexico

This paper documents the Eocene to Miocene dinoflagellate cyst assemblages found at Site 94 in the southern part of the Gulf of Mexico. Four unique dinoflagellate cyst assemblages representing depositional periods from the Early Eocene to the Early Miocene are defined in this study. The Early to Middle Eocene assemblage presents the highest average concentrations of dinoflagellate cysts, is dominated by Operculodinium, and contains few heterotrophic taxa. The Early Oligocene assemblage has medium concentration and is dominated by Deflandrea. The Late Oligocene also has high average concentrations of dinoflagellate cysts, is dominated by Homotryblium, and contains few heterotrophic taxa. The Early Miocene assemblage has lower average concentrations of dinoflagellate cysts, is dominated by Pyxidinopsis, and lacks heterotrophic taxa. Our palynological data is related to significant regional paleogeographic and paleoceanographic changes. Namely, the Early to Middle Eocene free flow of tropical water masses from the south and the Late Eocene restriction of this flow by a land bridge connecting northern South America to Cuba in the north. The Oligocene gradual return of the tropical water masses and finally, the Early Miocene emergence of the Florida Platform when the Gulf of Mexico reached modern oceanographic conditions. The stratigraphic ranges of selected dinoflagellate cysts fit in age with previous microfossil data from the site and allowed us to define the Early Oligocene - Late Oligocene transition. The presence of well-preserved dinoflagellate cysts allowed the identification of 60 species and the discovery of three new species: Achomosphaera psilata sp. nov., Carpatella reticulata sp. nov., and Hystrichosphaeropsis gulficum sp. nov.

High microplastic pollution in marine sediments associated with urbanised areas along the SW Bulgarian Black Sea coast

This study aims to provide baseline data on microplastic (MP) concentrations in beach and seabed sediments of the SW Black Sea coast, and to identify possible sources of MP pollution in the area. MP concentrations in beach sediments in urbanised coastal areas, as well as in all seabed sediments, were on average higher than in other parts of the Black Sea and most other European seas. Urban coastal areas showed the highest average MP concentrations (mean ± SD): 464.44 ± 272.50 MP·kg−1 dry sediment in beach samples, 825.93 ± 396.30 MP·kg−1 dry sediment in seabed samples, while coastal sediments in an area with no local anthropogenic activities had significantly lower average MP concentrations: 84.44 ± 147.57 MP·kg−1 in beach samples, and 550.62 ± 245.71 MP·kg−1 in seabed samples. Possible identified sources of MPs include sewage water discharges, urban waste, coastal fisheries and aquaculture, as well as accumulation of marine litter on beaches and in adjacent offshore areas, serving as sources of secondary MP pollution.

Risk assessment and quantification of elemental concentrations in river and stream in Nigeria

The rising prevalence of elements in surface water is becoming a major global environmental problem due to their resistance to change and capacity to accumulate in organisms. Humans are causing significant heavy metal contamination in the aquatic environment, which is killing aquatic creatures. The purpose of this study is to determine the elemental composition of surface water in Ogun State. Water samples were collected from a river that flows alongside Liberty Estate in Ewupe, Ado-Odo Ota Local Government Area, and a stream that runs alongside Pacific Estate in Iganmode. The element composition of water samples was determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Several components were found to exceed the limitations imposed by the World Health Organisation (WHO) and the Environmental Protection Agency (EPA). In River I, sodium (Na) had the highest apparent concentration, whereas titanium (Ti) had the lowest average concentration. In River II, silicon (Si) had the highest apparent concentration, whereas chromium (Cr) had the lowest average concentration. Titanium (Ti) had the lowest mean concentration value, whereas sodium (Na) appeared to have the highest concentration in stream I. Stream II has the highest concentration of sodium (Na), while Uranium (U) has the lowest average concentration value. Nonetheless, the incremental lifetime cancer risk (ILCR) values for adults and children who drink river and stream water are similar, ranging from 10–9 to 10–8. This implies a high carcinogenic risk (CR) linked with drinking water from both sources. Children who had access to both stream and river water demonstrated higher risk levels than adults. Routine studies of the state's streams and rivers should be conducted to avoid the subtle impact that may emanate from the water bodies.

Planted species influences soil phosphorus losses in a historically fertilized pasture system: A mesocosm study

AbstractThe gradual accumulation of phosphorus from historical fertilization can contribute to the eutrophication of surface waters by increasing the potential for subsurface leaching losses. Grazing lands areas are a priority for concern, and phytoremediation efforts in grazing lands have prioritized grasses that may be used as forage for cattle. This study investigated the influence of three different forage species—Paspalum notatum, Hemarthria altissima, and Cynodon nlemfuensis—on the loss of phosphorus in leachate from surface soils. The experiment used a nested pot mesocosm design that allowed us to monitor leachate volume and concentration biweekly over the course of 3 months. Pots containing P. notatum plants leached significantly more phosphorus than pots containing C. nlemfuensis or empty pots with no plants growing in them, despite losing an equivalent amount of water. H. altissima lost equivalent amounts of phosphorus in leachate water, but each H. altissima plant removed approximately 33.6 mg of phosphorus, approximately 2.5× that removed by P. notatum (13.4 mg). C. nlemfuensis had lower average leachate phosphorus concentrations at each biweekly sampling than either plant species (C. nlemfuensis‐P. notatum, padj = 0.001; C. nlemfuensis‐H. altissima, padj = 0.02), averaging only 0.110 ppm in leachate relative to 0.175 ppm and 0.200 ppm in pots beneath H. altissima and P. notatum, respectively. This, combined with C. nlemfuensis' slightly higher‐than‐average aboveground P content and overall aboveground biomass expression suggest it is the best possible phytoremediation candidate. As even minor leachate P loads can be critically threatening to neighboring oligotrophic water bodies, if the conservation of downstream environments is the priority, the short‐term threat of increased leachate must be considered. Further research is needed to explore the underlying mechanisms and field‐scale implications of these findings.

Air pollutant removal performance using a BiLSTM-based demand-controlled ventilation method after tunnel blasting

Efficient tunnel ventilation is essential for ensuring construction safety and protecting personnel health during tunnel construction. This study proposes a demand-controlled ventilation (DCV) method on the basis of deep learning algorithm to both improve pollutant removal efficiency and reduce energy consumption. The DCV method utilizes a two-layer bidirectional long short-term memory algorithm (BiLSTM) to predict pollutant concentrations. The air volume is dynamically adjusted based on the gaseous pollutant removal requirements. The coefficient of ventilation performance (COVP) is proposed to evaluate the performance of two ventilation methods (DCV and constant air-volume ventilation (CAV)) through computational fluid dynamics (CFD) simulations. The results show that the DCV results in a lower maximum average CO concentration and higher removal efficiency in the heading area (372.3 mg/m3) than the CAV does (404.1 mg/m3). The fan's energy consumption of DCV is 64.6% lower than that of CAV during a 1000 s ventilation period. The COVPs for both methods exhibit temporal variation and achieves their maximums (2.25 for DCV and 0.741 for CAV) after reaching the constraint conditions (air volume threshold). The DCV method expedites pollutant elimination, reduces construction waiting period, and minimizes energy consumption, providing a novel application of a deep learning algorithm in construction engineering.

Environmental and energy efficiency of a selected municipal wastewater treatment plant – a case study

Based on the analysis of environmental and energy efficiency in the years 2019–2021 in the selected sewage treatment plant (WWT) located in the southern Poland with mechanical-biological wastewater treatment, it was found that the highest level of pollution reduction of 98% enabled the highest BOD5 concentration to be reduced more than 800 times. The operation of the sewage treatment plant was characterized by variable efficiency of the treatment process, which was demonstrated by significant differences in chemical indicators (BOD5, COD, P, TSS and N). Low average concentration of total nitrogen below 4 mg l−1 occurred with a reduction of pollutants at a level not exceeding 90%. Noticeable energy consumption of 1.58 kWh m−3 related to the increase in the amount of treated sewage, confirmed by a moderate correlation, indicated the need to optimize the treatment process.

Chemical Analysis and Agricultural Utilizations of Dams Reservoir Sediments

Sediment samples were collected from King Talal Dam (KTD) and subjected to chemical, physical, and mineralogical study to test their suitability as soil replacement. The concentration of Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), Nickel (Ni), Arsenic (As), Cobalt (Co), and Zinc (Zn) was obtained by atomic absorption spectrophotometer, and the elements phosphorus (P) and boron (B) were determined by using the spectrophotometric technique. These elements concentration was compared with the average concentration of soil in near by area of Jordan valley, It was found that the concentration of Cu and Zn, P, Fe, Mn, and K is within the standard range for soil fertility, and the concentration of Pb, Ni, As, Co, and Cd is within the standard range of agricultural human health safety regulation’s, the highest concentration on of iron (Fe) and manganese (Mn) in sediment were found to be 1.48% and 15.0 ppm respectively. The lowest average concentration in KTD sediment was identified for cadmium (Cd) and arsenic (As) and was found to be <0.01 and <0.05 ppm respectively. The Laboratory tests carried out indicate that the water of King Talal Dam is free of heavy metals pollutants, and reservoir sediments can be used for soil replacement and amendment. It is highly recommended to keep the percentage of sediments of KTD to soil used in agriculture within the range of 25%-50%.

Diet supplementation with Saccharomyces cerevisiae influences the electrophoretic parameters in blood in young Charolaise bulls.

The objective of the research was to investigate the effect of Saccharomyces cerevisiae supplementation on some acute-phase proteins, haptoglobin and all electrophoretic parameters in young Charolaise bulls. Sixty bulls were divided into two equal groups: the control group (CG) receiving the base diet without yeast supplementation and the diet supplementation group (YG) receiving the base diet with 5g of Saccharomyces cerevisiae supplementation. The base diet was total mixed ration allocated at 11.85 kg per animal per day. Blood samples were collected from all bulls on day 0 before the start of the diet supplementation, and on days 20 and 40 after the start. Total proteins, albumin, globulin fraction (α1-, α2-, β1-, β2- and γ-globulins), albumin: globulin ratio (A: G) and haptoglobin were determined. Two-way analysis of variance showed a significant effect of the yeast feeding time on all studied parameters except α2-globulins in both groups. The YG showed a higher average concentration of total proteins, albumin and A: G and a lower average concentration of γ-globulins and haptoglobin than the CG. These results indicated the beneficial effect of the Saccharomyces cerevisiae on the inflammatory status of the young bulls, which showed an adequate response in serum levels of the acute-phase proteins tested.

Abstract PO5-14-11: Leveraging a pharmacokinetic/pharmacodynamic (PK/PD) model to guide dose optimization of palbociclib (palbo) in combination with vepdegestrant

Abstract Background: Vepdegestrant is a potent, selective, orally bioavailable PROteolysis TArgeting Chimeric (PROTAC) estrogen receptor (ER) degrader. A phase 3 study will evaluate the combination of vepdegestrant and palbo in participants with ER+, human epidermal growth factor receptor negative (HER2[-]) advanced/metastatic breast cancer (NCT05909397). The recommended starting dose of palbo is 125 mg once daily for 3 weeks followed by 1 week off treatment for each 28-day cycle in combination with aromatase inhibitors or fulvestrant.1 Neutropenia is the most frequently reported adverse event for patients receiving palbo in clinical trials.1 When co-administered with vepdegestrant in a phase 1b cohort of the first-in-human phase 1/2 study (NCT04072952), higher rates of medically manageable neutropenia and increased palbo concentrations were observed compared with historical studies of palbo administered with letrozole or fulvestrant.1 Reduced starting doses of palbo (100 mg, 75 mg) are planned to mitigate increased rates of Grade 4 neutropenia while maintaining similar palbo exposure when combined with vepdegestrant. The analysis objective was to leverage a PK/PD model to simulate palbo exposure and neutropenia taking into consideration the dose modification and management for hematologic toxicities provided in the palbo prescribing information.1 Methods: A Monte-Carlo simulation platform2 was utilized to monitor absolute neutrophil count (ANC) in 1000 patients with weekly monitoring over 4 cycles (112 days) of palbo administration. Simulated ANC was determined using a semi-mechanistic model of chemotherapy-induced myelosuppression as previously described.3 Palbo dose modification methods included both dose hold and reduction based on an individual’s ANC and thresholds for Grade 3 (< 1000 mm3) or Grade 4 (< 500 mm3) neutropenia. Simulated neutropenia and exposures from palbo starting doses of 100 mg and 75 mg in the presence of a 25%, 49%, and 67% increase in typical exposure were compared to a palbo starting dose of 125 mg in the absence of increased exposure (historical reference). Average concentration is calculated as the cumulative area under the curve divided by the simulation duration. Results: After a 4-cycle simulation, the 100 mg starting dose of palbo simulated across varying levels of increased exposure resulted in similar Grade 4 neutropenia incidence and average concentration compared to the reference simulation (< 12% difference). The 75 mg starting dose of palbo simulated across varying levels of increased exposure resulted in lower Grade 4 neutropenia incidence as well as lower average concentration compared to the reference simulation (Table 1). Conclusion: The PK/PD model simulation allows for relative comparison of Grade 4 neutropenia incidence and average palbo concentration between the planned reduced starting doses of palbo in the context of increased exposure relative to standard palbo dosing, i.e., without vepdegestrant. This simulation indicates a reduced dose of palbo (100 mg) in combination with vepdegestrant produces similar incidence of Grade 4 neutropenia and comparable average palbo concentration compared to historical reference providing additional support for the study lead-in of NCT05909397. Citations: 1. IBRANCE® (Palbociclib) [Package Insert]. New York, US: Pfizer, Inc. 2. Jermain et al. ACOP13 2023. 3. Friberg et al. J Clin Oncol 2002. Table 1. 4-cycle simulation results comparing reduced starting doses of palbociclib in the presence of increased typical exposure to a reference standard palbociclib dosing in the absence of increased exposure Citation Format: Brian Jermain, Derek Yang, Weiwei Tan, Julia Perkins-Smith, Justin Hoffman, Jason Williams. Leveraging a pharmacokinetic/pharmacodynamic (PK/PD) model to guide dose optimization of palbociclib (palbo) in combination with vepdegestrant [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-14-11.

Comparing methanol and glycerol as carbon sources for mainstream partial denitrification/anammox in an IFAS process.

This study explored the implementation of mainstream partial denitrification with anammox (PdNA) in the second anoxic zone of a wastewater treatment process in an integrated fixed film activated sludge (IFAS) configuration. A pilot study was conducted to compare the use of methanol and glycerol as external carbon sources for an IFAS PdNA startup, with a goal to optimize nitrogen removal while minimizing carbon usage. The study also investigated the establishment of anammox bacteria on virgin carriers in IFAS reactors without the use of seeding, and it is the first IFAS PdNA startup to use methanol as an external carbon source. The establishment of anammox bacteria was confirmed in both reactors 102 days after startup. Although the glycerol-fed reactor achieved a higher steady-state maximum ammonia removal rate because of anammox bacteria (1.6 ±0.3g/m2/day) in comparison with the methanol-fed reactor (1.2±0.2g/m2/day), both the glycerol- and methanol-fed reactors achieved similar average in situ ammonia removal rates of 0.39 ±0.2g/m2/day and 0.40 ±0.2g/m2/day, respectively. Additionally, when the upstream ammonia versus NOx (AvN) control system maintained an ideal ratio of 0.40-0.50 g/g, the methanol-fed reactor attained a lower average effluent TIN concentration (3.50 ±1.2mg/L) than the glycerol-fed reactor (4.43 ±1.6mg/L), which was prone to elevated nitrite concentrations in the effluent. Overall, this research highlights the potential for PdNA in IFAS configurations as an efficient and cost-saving method for wastewater treatment, with methanol as a viable carbon source for the establishment of anammox bacteria. PRACTITIONER POINTS: Methanol is an effective external carbon source for an anammox startup that avoids the need for costly alternative carbon sources. The methanol-fed reactor demonstrated higher TIN removal compared with the glycerol-fed reactor because of less overproduction of nitrite. Anammox bacteria was established in an IFAS reactor without seeding and used internally stored carbon to reduce external carbon addition. Controlling the influent ammonia versus NOx (AvN) ratio between 0.40 and 0.50 g/g allowed for low and stable TIN effluent conditions.

Temporal variation and pollution status of heavy metals in core sediments from Jiangsu intertidal area, China

Eight heavy metal concentrations were analyzed from a 60.35-m-long sediment core in the Jiangsu intertidal area, China. Based on the lithofacies characteristics, mean grain size, downcore distributions of elements, and accelerator mass spectrometry (AMS) 14C and optically stimulated luminescence (OSL) data, the sediments in the core were divided into three units that formed during marine isotope stages 4 (MIS 4), MIS 3, and MIS 1. Except for Cd, all the other heavy metals had the lowest average concentrations in U3, which formed during MIS 4 with the coarsest sediment, representing a fluvial deposit. Most of the heavy metals were positively correlated with Al, Fe, and the total organic carbon (TOC), indicating these metals had the same sources. Pearson's correlation coefficient, enrichment factor, geoaccumulation index, and principal component analysis suggested that there was no element enrichment or contamination in the core sediments and that all heavy metals were naturally sourced.

Robustness of point measurements of carbon dioxide concentration for the inference of ventilation rates in a wintertime classroom

Indoor air quality in schools and classrooms is paramount for the health and well-being of pupils and staff. Carbon dioxide sensors offer a cost-effective way to assess and manage ventilation provision. However, often only a single point measurement is available which might not be representative of the CO₂ distribution within the room. A relatively generic UK classroom in wintertime is simulated using Computational Fluid Dynamics. The natural ventilation provision is driven by buoyancy through high- and low-level openings in both an opposite-ended or single-ended configuration, in which only the horizontal location of the high-level vent is modified. CO₂ is modelled as a passive scalar and is shown not to be ‘well-mixed’ within the space. Perhaps surprisingly, the single-ended configuration leads to a ‘more efficient’ ventilation, with lower average CO₂ concentration. Measurements taken near the walls, often the location of CO₂ sensors, are compared with those made throughout the classroom and found to be more representative of the ventilation rate if made above the breathing zone. These findings are robust with respect to ventilation flow rates and to the flow patterns observed, which were tested by varying the effective vent areas and the ratio of the vent areas.

Exploring the potential of the Vanilla species from the Brazilian Atlantic Forest: Sensory description and consumer acceptance

AbstractThe present work aimed to explore, for the first time, the sensory potential of three native species of Vanilla collected in the Brazilian Atlantic Forest (V. bahiana, V. chamissonis, V. cribbiana). Ethanolic extracts of vanilla species were obtained from the ripe, enzymatically cured pods, and added to lactose‐free milk making vanilla flavored milk samples. Threshold estimation differences of “vanilla flavor,” and hedonic and sensory consumer perception of samples were evaluated. A 9‐point hedonic scale and the Rate‐All That‐Apply methodology were used for comparison to the commercial species (V. planifolia) and an artificial essence. All native species showed lower average threshold concentrations than the commercial species extract. There was no significant difference in the perception of “vanilla aroma” between V. cribbiana and the commercial species, and neither V. cribbiana nor V. chamissonis showed significant difference to the artificial essence or V. planifolia extract for “sweet taste.” Among the evaluated species, V. cribbiana seemed to show the greatest potential for market success.Practical ApplicationsThe species of Vanilla sp. explored in this work have already been chemically evaluated and presented the components related to the vanilla flavor. However, the mere presence of chemical compounds does not guarantee aroma perception. Their relative concentrations, among other factors that are difficult to determine chemically, are indispensable for generating an agreeable flavor. The only reliable way to determine the acceptability of the flavor is through sensory analysis, applied in this work to prove the commercial potential of native species. Vanilla species native to the Atlantic Forest showed the sensory potential to be used as substitutes for commercial species and to be applied in the genetic improvement of varieties. These native species may be introduced to “gourmet” consumers as vanilla flavors with different nuances. Their production may favor the areas where they are cultivated, bringing economic development to the population, and helping to maintain the forest areas.

Tensile failure mechanisms investigation of mesophase pitch-based carbon fibers based on continuous defective graphene nanoribbon model

Mesophase pitch (MPP)-based carbon fibers exhibit outstanding mechanical properties, notably an exceptionally high Young’s modulus. Despite extensive investigations into the microstructure of MPP-based carbon fibers, the influence of these factors on deformation mechanisms under tension remains unclear. This study employs the continuous defective graphene nanoribbons (dGNR) atomistic structure model for molecular dynamics simulations to explore the tensile failure mechanisms of MPP-based carbon fibers. In the simulation model, the structure of the defective region was generated through high-temperature annealing, and a transition region was introduced to prevent distortion and damage to the active graphene edges. The simulation reveals the evolutionary process of the microstructure of MPP-based carbon fibers under tension and achieves Young’s modulus predictions with greater accuracy than theoretical models. Additionally, the study shows that different strengths of interactions between adjacent graphene nanoribbons can lead to two distinct failure modes. Models with larger crystallite dimensions along the fiber axis and lower average defective concentrations exhibit geometric deformation coordination between adjacent nanoribbons, potentially elucidating the increasing strength trend in MPP-based carbon fibers with rising graphitization levels. Our simulations provide insights into the tensile failure mechanisms of MPP-based carbon fibers, offering valuable guidance for regulating their microstructure to enhance mechanical performance.

The links between positive human interaction and maternal behaviour and welfare of commercial breeding dams (Canis familiaris)

In dogs, maternal behaviour plays an essential role in offspring survival and can influence the development and behaviour of the neonate later in life. We investigated the effect of prepartum enrichment on maternal behaviour and welfare of breeding dams at a large-scale commercial dog breeding establishment. During the last four weeks of gestation, dams were exposed to either baseline management conditions (control N = 13) or an additional enrichment protocol based on positive human interaction (enriched N = 13). We then recorded the duration of mother-puppy interactions throughout the first three weeks postpartum. Hair samples for cortisol analysis were collected at four timepoints: 3rd week of gestation, last week of gestation, 4th week postpartum, and 8th week postpartum. Additionally, the behaviour of the dams was assessed during the 3rd week of gestation. We hypothesised that, compared to control dams, enriched mothers would show higher levels of maternal behaviour and lower post-treatment and post-partum levels of hair cortisol. With the exception of vertical nursing, all the recorded maternal behaviour variables declined over time. None of the maternal behaviour variables were significantly affected by the enrichment treatment. However, as litter size increased, enriched dams spent marginally more time nursing their puppies in a sitting or standing posture (vertical nursing). Similarly, as litter size increased, enriched dams had significantly lower average hair cortisol concentration (HCC) levels compared to dams in the control group. Furthermore, dams scoring higher in the pre-treatment behavioural assessment (being more social towards humans and other dogs, less fearful and reactive, and more willing to play and interact with unfamiliar stimuli) had lower HCC levels. HCC did not vary significantly across the four timepoints. Overall, these findings suggest that although higher HCC levels in dams bearing larger litters could be associated with elevated energy mobilisation during pregnancy and lactation, a potential stress-mitigating effect of the positive human interaction cannot be excluded. Further studies should investigate this potential stress-mitigating effect using additional welfare indicators.

Atmospheric black carbon in a key location of the Chilean Central Andes: Identifying patterns, sources, and potential impacts

Black carbon (BC) has been identified as one of the primary contributors to climate change, primarily due to its exceptional capacity to absorb solar radiation. This leads to a reduction in the albedo of ice and snow surfaces, consequently accelerating their melting. In this work, measurements of atmospheric BC are presented, carried out from October 2016 to December 2019 in Portillo, Chilean Central Andes, in the NUNATAK-1 laboratory refuge (3000 m.a.s.l). This site is close to the Chile-Argentina border and is situated along a heavily trafficked road connecting the two countries. Owing to weather conditions, this route operates on a seasonal schedule, remaining open 24 h during warmer months, while in winter, traffic is restricted to the hours between 8 a.m. and 8 p.m. Access to vehicles is prohibited during periods of heavy snowfall. BC concentrations were continuously monitored by a Multi-Angle Absorption Photometer (MAAP). The variability and temporal cycles of BC levels were investigated in relation to local vehicular activity and meteorological parameters, through multiple linear regression analysis. Results show that vehicular traffic variations led to a systematic pattern in the atmospheric BC measured, with a preponderant role of meteorological factors. During the summer months, BC levels reached their peak (mean of 0.77 μg m−3), with maximum values recorded during the nighttime and early morning hours. In line with this finding, summer counted the highest number of vehicles circulating in the area. In contrast, the winter months exhibited lower average BC atmospheric concentrations compared to summer months (0.35 μg m−3), characterized by a distinct hourly profile. In a complementary way, forward trajectories using the HYSPLIT model were performed for various meteorological conditions. The findings indicated that emissions from the study area had the potential to extend to neighboring glaciers. This impact on the basins' hydrology, vital and fragile components of the Andean region, magnifies climate change effects in these cryospheric zones. Notably, the latest IPCC report highlights limited research on aerosol effects on mountain snow and glaciers. This study also presents the first estimates of high-altitude BC source assessments in Chile and South America. These insights could enhance global atmospheric models in mountainous regions, enhancing their accuracy and utility.

Oral bioavailability and egg drug residue of lincomycin in laying hens after different treatment

Lincomycin (LCM) is an antibiotic used to treat severe bacterial infections in livestock and companion animals. In this study, we aimed to investigate the oral bioavailability of LCM with PK data after IV and PO administration and to compare differences in drug residue patterns in eggs. To ensure food safety, an additional study on egg residue was conducted using 3 different commercial LCM drugs. For bioavailability study, laying hens were divided into oral and intravenous (n=8/group) groups and received single dose (10 mg/kg) of LCM. The limits of quantification for LCM were 0.729 μg/mL and 0.009 mg/kg in plasma and eggs, respectively. The oral group exhibited a significantly lower average serum drug concentration than the IV group, with a bioavailability of 2.6%. Furthermore, the egg residue profiles confirmed reduced systemic drug exposure after oral administration. For the commercial LCM drug egg residue experiment, laying hens were divided into low- and high-dose groups (n=12/group) for each drug and treated with the recommended dosage and administration method for each respective drug. The eggs were collected and analyzed until 14 d after the last drug treatment. Despite differences in the LCM content and formulation among commercial drugs, all the tested commercial drugs showed average concentrations below the MRL in eggs within approximately 3 d after the last drug treatment. In this study, we have confirmed that LCM has a low oral absorption rate in laying hens, and this was consistent with the findings from the egg residue profiles. Further studies are requested to elucidate the exact reasons for evidently low oral drug absorption in laying hens.

Sebaran Particulate Matter (PM10, PM2,5, PM1, PM0,1) di SMP Negeri 1 Kota Jambi Menggunakan Model CFD (Computational Fluid Dynamics)

One source that contributes greatly to urban air quality is traffic. The proximity of schools to vehicles will put students at greater risk of exposure to high concentrations of particulate matter. SMP Negeri 1 Jambi City is an education center located in an urban area and adjacent to a busy road. CFD models are good at modeling the movement of pollutants in urban areas by taking into account the influence of buildings. The purpose of this study is to determine the concentration of PM10, PM2.5, PM1, and PM0.1 at SMPN 1 Jambi City based on direct measurement results and CFD modeling results and then see how accurate the modeled PM concentrations are when compared to the results of direct measurements. The results showed that the average concentrations of PM10, PM2.5, PM1, and PM0.1 from direct measurements were 20.66 µg/m3, 11.79 µg/m3, 8.74 µg/m3, and 1.96 µg/m3, respectively, while the modeling results showed lower average concentrations. The ratio of the difference between the measured and modeled PM concentrations is in the range of 11.67 - 233.45% and with the percentage of RMSPE obtained >30% (invalid), where the requirement for a modeling to be valid so that the results can be trusted in explaining the actual phenomenon is when the validity percentage is <30%.

A hydrogen diffusion model considering grain boundary characters based on crystal plasticity framework

The influence of grain boundaries (GBs) on hydrogen transportation is a crucial factor in understanding the mechanisms of hydrogen embrittlement (HE) in polycrystalline alloys. Crystal plasticity models have the advantages in simulating the effect of grain microstructure on hydrogen diffusion in polycrystals, but they have not yet been coupled with hydrogen diffusion models that can take into account GB characters. In this study, a hydrogen diffusion model that considers the effect of GBs on the transportation of hydrogen was developed to study the local hydrogen diffusion behavior in bi-crystalline and polycrystalline alloys. The simulation results showed the capability of the model in describing the influence of hydrogen on the material deformation. In addition, this study found that the hydrostatic stress determined the hydrogen concentration in the far-GB region, whereas the GB energy played a control role in and near the GB regions. Notably, hydrogen exhibits a preference for localization near high-angle grain boundaries (HAGBs) and triple junctions. In alloys with medium grain size, hydrogen typically had low average concentration with a more uniform distribution. Furthermore, the hydrogen-assisted crack growth mechanism was analyzed as the continuous coalescence of primary and secondary cracks along GBs. This work presents a hydrogen diffusion model that considers GB effects, and the proposed model has advantages in predicting the deformation and fracture of polycrystalline alloys in hydrogen environments.

Evaluation of Trace Elements in Coffee and Mixed Coffee Samples Using ICP-OES Method.

This research examines the concentration of 10 trace elements including arsenic (As), lead (Pb), chromium (Cr), zinc (Zn), iron (Fe), cobalt (Co), cadmium (Cd), nickel (Ni), manganese (Mn), and aluminum (Al) from among 36 different samples of coffee (3 brands and 2 types of simple and instant) and mixed coffee (3 brands and 4 types of simple, creamy, chocolate and sugar free) collected from market of Iran's and analyzed by using ICP-OES (inductively coupled plasma-optical emission spectrometry). The recovery, limit of quantification (LOQ), and limit of detection (LOD) ranged from 93.4 to 103.1%, 0.06 to 7.22, and 0.018 to 2.166 µg/kg, respectively. The findings showed that the highest and lowest average concentrations were 498.72 ± 23.07 μg/kg (Fe) and 3.01 ± 1.30 μg/kg (As) in coffee and mixed coffee samples. Also, in all samples, the maximum concentration of trace elements was related to Fe (1353.61 µg/kg) and the minimum concentration was related to Al, As, Co, Cr, Ni, Pb, and Zn that were not detected (ND). The samples of mixed coffee had highest levels of trace elements compared to coffee samples. In coffee samples, type of instant coffee had highest levels of trace elements compared to simple coffee and mixed coffee samples. The type of creamy mixed coffee had highest levels of trace elements (except Ni and Cr) compared to other type of mixed coffee samples. Finally, trace elements were less than the standard levels of Iran and other countries (in all samples); therefore, it does not threaten Iranian consumers.