Actual Concentration Research Articles

Constructing the Electron-Rich Microenvironment of an All-Polymer-Based S-Scheme Homostructure for Accelerating Uranium Capture from Nuclear Wastewater.

Large quantities of uranium-containing radioactive wastewater are typically generated during nuclear fuel cycle processes. Despite significant efforts, efficient capture of migratable hexavalent uranium U(VI) is still a huge challenge due to its acidity, radioactivity, coexisting organics, and high impurity cation abundance in wastewater. Herein, we have fabricated all-polymer-based 0D/2D C4N/C6N7 homostructure hybrids with an S-scheme electronic configuration by coordinating the band engineering of semiconductors to enrich uranium species from the complex wastewater environment. The sample can capture over 97% of U(VI) in the actual concentration of nuclear industrial reprocessing wastewater; also, the U(VI) enrichment ratio still exceeds 95% when the irradiation dose (including α, β, and γ) is up to 100 kGy. Density functional theory and X-ray absorption spectroscopy demonstrate that the aggregation of charge carriers on the surface of the sample regulates the electron-rich microenvironment, thus accelerating the reduction conversion of single electron reaction uranium disproportionation. It is expected that this work can provide more insight into other functional materials, thereby promoting uranium removal advancements in nuclear wastewater.

Self-Calibrating Fluorimetric Analysis of Single-Wall Carbon Nanotube Samples for Electronics Applications

Semiconducting single-wall carbon nanotubes (SWCNTs) are a leading candidate to replace or supplement silicon in future generation chip manufacturing. Because they are produced as structural mixtures with varied electronic properties, SWCNTs must first be carefully sorted and purified. This requires new metrology tools that can reliably measure SWCNT sample compositions to guide sorting processes and confirm product purity. We describe here a novel, self-calibrating optical instrument designed for advanced characterization of SWCNT samples. This desktop system will quickly, sensitively, and non-destructively quantify the concentrations of multiple SWCNT (n,m) species. The key advance is adding variance spectroscopy to rapid excitation-emission fluorimetry. Variance spectroscopy is a recently developed method that can determine absolute concentrations of nanoparticles by analyzing statistical variations in the fluorescence signals from small volumes of dilute samples. Measurements are made by a small accessory module linked to a standard NanoSpectralyzer. It will automatically acquire and analyze variance spectra to find the sensitivity calibration factors needed to convert raw fluorescence intensities into actual concentrations of the different SWCNT species. Those measured calibration factors are valid for subsequent samples with similar processing histories, allowing rapid quantitation from quick excitation-emission scans. We expect that this analytical capability will support advances in basic carbon nanotube science and applications.

Nanoplastics enhanced the developmental toxicity of aromatic disinfection byproducts to a marine polychaete at non-feeding early life stage

Micro/nanoplastics can act as vectors for organic pollutants and enhance their toxicity, which has been attributed to the ingestion by organisms and the “Trojan horse effect”. In this study, we disclosed a non-ingestion pathway for the toxicity enhancement effect of nanoplastics. Initially, the combined toxicity of polystyrene microplastics (40 μm) or nanoplastics (50 nm) with three disinfection byproducts (DBPs) to a marine polychaete, Platynereis dumerilii, was investigated. No toxic effect was observed for the micro/nanoplastics alone. The microplastics showed no effect on the toxicity of the three DBPs, whereas the nanoplastics significantly enhanced the toxicity of two aromatic DBPs when the polychaete was in its non-feeding early life stage throughout the exposure period. The microplastics showed no interaction with the P. dumerilii embryos, whereas the nanoplastics agglomerated strongly on the embryonic chorion and fully encapsulated the embryos. This could contribute to higher actual exposure concentrations in the microenvironment around the embryos, as the concentrations of the two aromatic DBPs on the nanoplastics were 1200 and 120 times higher than those in bulk solution. Our findings highlight an important and previously overlooked mechanism by which nanoplastics and organic pollutants, such as DBPs, pose a higher risk to marine species at their vulnerable early life stages. This study may contribute to a broader understanding of the environmental impacts of plastic pollution and underscore the necessity to mitigate their risks associated with DBPs.

Comparative Acute Toxicity Studies of Chlorpyrifos Technical Grade with its Emulsifiable Concentrate (20% EC) on Labeo rohita, a Freshwater Major Carp, and Mystus vittatus, a Freshwater Catfish.

Chlorpyrifos is widely used across the world as an organophosphate insecticide and frequently contaminates freshwater bodies through runoff from agricultural fields. In the laboratory, static bioassays were undertaken to examine differences in acute toxicity caused by exposure to the technical grade (94% a.i.) and an emulsifiable concentrate (20% EC) of chlorpyrifos to two species of freshwater fish, Labeo rohita and Mystus vittatus. The recovery of actual chlorpyrifos concentrations varied from 83% (technical grade, T) to 89% (emulsifiable concentrate, F) after two hours in water. The susceptibilities of the two fish species to the two types of chlorpyrifos varied. The 96-h LC50 values for T and F chlorpyrifos in L. rohita were 68 and 36µg/L, respectively, and 120 and 62µg/L in M. vittatus, respectively. As the exposure period was extended, the LC50 values gradually decreased. LC50 values between the technical grade and formulation were compared following the criteria of Mayer et al. (1986), Schmuck et al. (1994), APHA (1995), and Demetrio et al. (2014). It was concluded from the study that the emulsifiable concentrate (20% EC) of chlorpyrifos was more toxic than technical-grade chlorpyrifos.

Centrifugation is an effective and inexpensive way to determine Batrachochytrium dendrobatidis quantity in water samples with low turbidity

Batrachochytrium dendrobatidis (Bd) is a pathogenic chytrid fungus that is particularly lethal for amphibians. Bd can extirpate amphibian populations within a few weeks and remain in water in the absence of amphibian hosts. Most efforts to determine Bd presence and quantity in the field have focused on sampling hosts, but these data do not give us a direct reflection of the amount of Bd in the water, which are useful for parameterizing disease models, and are not effective when hosts are absent or difficult to sample. Current methods for screening Bd presence and quantity in water are time, resource, and money intensive. Here, we developed a streamlined method for detecting Bd in water with low turbidity (e.g., water samples from laboratory experiments and relatively clear pond water from a natural lentic system). We centrifuged water samples with known amounts of Bd to form a pellet and extracted the DNA from that pellet. This method was highly effective and the resulting concentrations across all tested treatments presented a highly linear relationship with the expected values. While the experimentally derived values were lower than the inoculation doses, the values were highly correlated and a conversion factor allows us to extrapolate the actual Bd concentration. This centrifuge-based method is effective, repeatable, and would greatly expand the domain of tractable questions to be explored in the field of Bd ecology. Importantly, this method increases equity in the field, because it is time- and cost-efficient and requires few resources.

Real-time prediction of the chemical oxygen demand component parameters in activated sludge model using backpropagation neural network

Activated sludge models are increasingly being adopted to guide the operation of wastewater treatment plants. Chemical oxygen demand (COD) is an indispensable input for such models. To ensure that the activated sludge mathematical model can adapt to various water quality conditions and minimize prediction errors, it is essential to predict the parameters of the COD components in real-time based on the actual influent COD concentrations. However, conventional methods of determining the components' contributions are too intricate and time-consuming to be really useful. In this study, the chemical oxygen demand in the actual waste water treatment plant was disassembled and analyzed. The research involved determining the proportions of each COD component, assessing the reliability of the measurement parameters, and examining potential factors affecting measurement accuracy, including weather conditions, pipeline conditions, and residents' habits. Then, a backpropagation neural network was developed which can deliver real-time predictions for five important contributors to COD in real time. In addition, using the receiver operating characteristics curve and prediction accuracy to evaluate the performance of the prediction model. For all five components, which SS, XS, SI, XA, and XH, the prediction accuracy of model was more than 80 %. The maximum deviation values of these parameters fall within the range of the actual detected values, suggesting that the model's predictions align well with real-world observations, and demonstrated prediction performance adequate for practical application in wastewater treatment. This article can provide research basis for the engineering application of activated sludge model and help for the intelligent upgrading of waste water treatment plants.

Relevance of plasma lenvatinib concentrations and endogenous urinary cytochrome P450 3A activity biomarkers in clinical practice.

Lenvatinib (LEN), a multitarget tyrosine kinase inhibitor used in various cancer treatments, is mainly metabolized by cytochrome P450 3A (CYP3A) enzymes. The importance of therapeutic drug monitoring (TDM) in patients administered LEN has been proposed. Although some biomarkers of endogenous CYP3A activity have been reported, their utility in dosage adjustments has not been well evaluated. This study investigated the correlation between plasma LEN concentrations and endogenous urinary CYP3A biomarkers in clinical practice. Concentrations of plasma LEN (N = 225) and CYP3A biomarkers (cortisol, 6β-hydroxycortisol, deoxycholic acid, and 1β-hydroxydeoxycholic acid) in urine (N = 214) from 20 patients (hepatocellular carcinoma, N = 6; thyroid cancer, N = 3; endometrial cancer, N = 8; and renal cell carcinoma, N = 3) collected for consultation for up to 1 year were evaluated using liquid chromatography-tandem mass spectrometry. Moreover, plasma trough LEN concentrations were predicted using a three-compartment model with linear elimination for outpatients administered LEN before sample collection. Moderate correlations were observed between the quantified actual concentrations and the predicted trough concentrations of LEN, whereas there was no correlation with endogenous urinary CYP3A biomarkers. The utility of endogenous urinary CYP3A biomarkers could not be determined. However, TDM for outpatients administered orally available medicines may be predicted using a nonlinear mixed effect model (NONMEM). This study investigated the utility of endogenous urinary CYP3A biomarkers for personalized medicine and NONMEM for predicting plasma trough drug concentrations. These findings will provide important information for further clinical investigation and detailed TDM.

Prediction of free chloride concentration in fly ash concrete by machine learning methods

Free chloride concentration distribution is important for assessing the corrosion risk of steel bars in reinforced concrete structures under chloride environment. In this study, a group of 3150 free chloride concentration data sets were obtained. Afterwards, three machine learning methods, namely support vector regression (SVR), multilayer perceptron (MLP) and one-dimensional convolutional neural network (1D-CNN) were adopted to construct models to predict chloride concentration distribution. The results show that 1D-CNN and MLP models are better at predicting the chloride concentration in fly ash concrete, whereas the prediction capability of SVR is relatively poor. Moreover, free chloride concentration prediction based on unmeasured parameters was conducted. The results show that the 1D-CNN and MLP models both have high prediction abilities – that is, predicted results are consistent with experimental measurements, performing generally better than the time-varying model constructed based on Fick's second law. When the free chloride concentrations were higher than 0.1%, the SVR model had a better prediction effect, but had unsatisfactory results and differed significantly from the actual chloride concentration when at a lower concentration. Overall, the 1D-CNN model performs the best in predicting free chloride concentration of concrete at different penetration depths, exposure time and with different fly ash content.

Unexpected changes in source apportioned results derived from different ambient VOC metrics

Although most source apportionments of VOCs use mixing ratios, about 23 % of published studies use mass concentrations. Thus, systematically exploring the changes in VOC source apportioned results caused by metric differences is important to assess the differences in key precursor apportionment results given the observed increases in O3 pollution situation. Different monitoring instruments measured hourly VOC volumetric concentrations in three typical Chinese cities (i.e., Qingdao, Shijiazhuang, and Zhumadian). Converting volumetric to mass concentrations under standard and/or actual temperature–pressure conditions, VOC values with different metrics were obtained. The impacts of different metrics on the source apportionments were then investigated. Compared to the positive matrix factorization of the volumetric data (VC-PMF), the VOC species concentrations with low relative molecular mass (RMM) in the factor profiles substantially decreased in mass data analyses (MC-PMF). However, those species with high RMM substantially increased. There were no substantial differences in the apportioned source contributions based on standard and actual condition mass concentrations. However, the high-low rankings of percent contributions apportioned using the volumetric and mass data produced substantial differences. Compared with the VC-PMF results, the percent contributions of sources dominated by species with low RMM (e.g., natural gas usage and mixed sources containing natural gas usage) apportioned by MC-PMF decreased, while those of sources that emitted high RMM species (e.g., solvent usage and mixed sources containing solvent usage) increased. Source apportionments based on the volumetric concentration data had more practical significance compared to the mass concentration data results for control strategy development since the mass data analyses created issues.

Fluorescence Quenching for Determination of Catalyst Concentration in the Parahydrogen‐Induced Polarization Method SABRE

AbstractIn recent years, parahydrogen‐induced hyperpolarization has become a focus for future medical applications. Similar to the established dynamic nuclear polarization method, a biocompatible bolus from a hyperpolarized sample can be produced for in vivo studies. However, this requires removing toxic hydrogenation catalysts, which inevitably must be used. Additionally, the ratio between the substrate to be hyperpolarized (e. g. pyruvate) and a mandatory catalyst must also be maintained. Even the smallest differences can lead to a reduction in generated signal amplification. In particular, weighing small amounts of catalysts leads to inaccuracies in sample preparations. Fluorescence spectroscopy provides a rapid and sensitive enough approach to determine catalyst concentration. The Ir‐IMes metal complexes used in SABRE lead to a quenching of the fluorescence of the solvent, dependent on its concentration. This can be used to quickly estimate the actual concentration in a solution with very small quantities of catalysts. Hence, fluorescence spectroscopy offers a rapid and reliable quality control method for the preparation of samples to be hyperpolarized. In addition, it can also be used as a quality control method to assess filtration efficacy before administration of hyperpolarized samples.

Degradation Kinetics of Antifouling Biocides in Sediment During the Spiking Equilibrium Phase

The new generation of antifouling biocides, as well as other emerging contaminants, has not yet been included in sediment quality guidelines or present standard protocols for sediment spiking. Most of these biocides have short half-lives in water, but little information is available regarding their degradation in sediments. Thus, there is a need to establish a reliable duration of the equilibrium phase for sediment spiking prior to sediment toxicity testing to determine the actual exposure concentrations during ecotoxicological tests. This study aimed to evaluate the degradation of DCOIT, Irgarol, Diuron, and Dichlofluanid during a spiking equilibrium phase of 24 h at three different time intervals (0, 6, and 24 h) and concentrations (10, 100, and 1000 ng g-1), by applying kinetic degradation models. The models presented a better fit for the 1000 ng g-1 treatments, in which the half-lives of DCOIT and Diuron were < 5 h, Dichlofluanid < 2 h, and Irgarol < 6h. Our results also indicate that, except for Dichlofluanid, the degradation rates of the other antifouling biocides were reduced dramatically after 6 h of equilibrium. Therefore, an equilibrium phase of 24 h (or greater than 6 h) was considered viable for sediment spiking. Our findings provide valuable information to guide future sediment toxicity tests using these compounds.

Exploring sources of inaccuracy and irreproducibility in the CDC bottle bioassay through direct insecticide quantification

BackgroundThe Centers for Disease Control and Prevention (CDC) bottle bioassay is a commonly used susceptibility test for measuring insect response to insecticide exposure. However, inconsistencies and high variability in insect response when conducting CDC bottle bioassays have been reported in previous publications. We hypothesized that the CDC bottle bioassay results may be compromised when expected and actual insecticide concentrations in the bottles are not equivalent and that inadequate bottle cleaning and/or loss during insecticide introduction and bottle storage steps could be responsible. We explored this hypothesis by quantifying insecticides using gas chromatography tandem mass spectrometry (GC-MS/MS) in bottles that had been cleaned, prepared, and stored according to the CDC guidelines.MethodsWe investigated the bottle cleaning, preparation, and storage methods outlined in the CDC bottle bioassay procedure to identify sources of irreproducibility. We also investigated the effectiveness of cleaning bottles by autoclaving because this method is commonly used in insecticide assessment laboratories. The two insecticides used in this study were chlorpyrifos and lambda-cyhalothrin (λ-cyhalothrin). Insecticides were removed from glass bioassay bottles by rinsing with ethyl-acetate and n-hexane and then quantified using GC-MS/MS.ResultsThe CDC bottle bioassay cleaning methods did not sufficiently remove both insecticides from the glass bottles. The cleaning methods removed chlorpyrifos, which has higher water solubility, more effectively than λ-cyhalothrin. Chlorpyrifos experienced significant loss during the bottle-coating process whereas λ-cyhalothrin did not. As for bottle storage, no significant decreases in insecticide concentrations were observed for 6 h following the initial drying period for either insecticide.ConclusionsThe CDC bottle bioassay protocol is susceptible to producing inaccurate results since its recommended bottle cleaning method is not sufficient and semi-volatile insecticides can volatilize from the bottle during the coating process. This can lead to the CDC bottle bioassay producing erroneous LC50 values. High levels of random variation were also observed in our experiments, as others have previously reported. We have outlined several steps that CDC bottle bioassay users could consider that would lead to improved accuracy and reproducibility when acquiring toxicity data.Graphical

Cannabinoid Content and Label Accuracy of Various Hemp-Derived Haircare, Cosmetic, and Edible Products Available at Retail Stores and Online in the United States.

Aim: To evaluate the label accuracy and content of various hemp-derived cannabidiol (CBD) products (cannabinoid products with ≤0.3% Δ9-tetrahydrocannabinol [THC]), as well as evaluate advertised claims on product labels. Methods: Hemp haircare, cosmetics, and food/drink products that were advertised to contain CBD were purchased from retail stores in the Baltimore, Maryland area (purchased in July 2020) and online (purchased in August 2020). Cannabinoid concentrations were measured using gas chromatography-mass spectrometry. Percent deviations between labeled and actual CBD concentrations were determined. Label information such as references to the Food and Drug Administration (FDA), external testing claims, and other claims (i.e., cosmetic or beauty, therapeutic, health halo effect, or "other") were quantified. Results: Ninety-seven products were purchased (35 in-store, 62 online). Of the 71 products with a specific total CBD amount on the label, 35 (49%) were underlabeled (>10% more CBD than advertised), 27 (38%) were overlabeled (>10% less CBD than advertised), and 9 (12.7%) were accurately labeled (within ±10% of labeled CBD). The median (range) percentage deviations were -53% (-100%-76%) for haircare products, +18% (-100%-1076%) for cosmetics, and -1% (-100%-4468%) for food/drinks. CBD label accuracy did not differ significantly between products with external testing claims versus those without (t40 = 0.23, p = 0.82). Overall, 24% of the 97 (total) products made a cosmetic or beauty claim (e.g., "skin looks more youthful"), 40% made a therapeutic claim (e.g., "pain relief"), and 86% made a health halo effect claim (e.g., "paraben-free," "dye-free," etc.). Most products (63%) did not include a disclaimer that claims had not been evaluated by the FDA. Conclusions: Most of the products included in this sample were inaccurately labeled for CBD content, including those claiming to have been tested by third party laboratories. A notable finding was that 10 products did not contain any CBD. Many products made therapeutic claims or used marketing tactics to seemingly convey they were safe/healthy, but only about one-third included disclaimers that these statements had not been evaluated by the FDA. These findings highlight the need for proper regulatory oversight of cannabinoid-containing products to ensure quality assurance and deter misleading or unfounded health claims in product marketing.

Optimization of ecofriendly L-Fe/Ni nanoparticles prepared using extract of black tea leaves for removal of tetracycline antibiotics from groundwater by response surface methodology

This article focuses on employment of nanotechnologies in remediation of tetracycline antibiotics (TC) from groundwater by green synthesized bimetallic Fe/Ni supported by limestone particles. An in-situ green synthesis nanoparticles was prepared using black tea leaves extract to generate a L-Fe/Ni nanocomposite. The synthesized nanocomposite was characterized using several techniques, such as, X-Ray Diffraction (XRD), Scanning Electron microscopy (SEM), transmission electron microscope (TEM), Energy dispersive X-ray (EDX), FTIR (Fourier Transform-Infra Red) spectroscopy and surface area. We then use response surface methodology (RSM) to optimize the synthesis process and evaluate the effectiveness of the prepared nanocomposite for tetracycline remediation. We took different simulated concentrations of the TC contaminant without relying on actual TC concentrations in grounwater, the best removal of the TC contaminant in batch study was investigated with relying on the initial concentrations of TC and other experimental factors such as pH, adsorbent nanomaterial concentration and time. A pilot plant was then constructed to eliminate the TC contaminant from groundwater in different concentrations, where the removal efficiency was found decreased with increasing in the concentration of the TC Many parameters affecting the removal mechanisms in statistical and continuous systems were examined to select the best results that accomplish the maximum elimination rate. With the improved operating conditions, (L-Fe/Ni concentration: 1500 mg/L; concentration of TC: 20 mg/L; pH: 7.2; contact time: 128 min), removal percent of TC was found 87 % based on RSM system. The L-Fe/Ni reactive medium of continuous column has a main role in slowing down the movement of the TC plume. This study showed that the ecofriendly nanocomposite could be an appropriate and novel method for remediation of antibiotics and other contaminants in groundwater.

Assessment of coffee leaves nutritive value via portable X-ray fluorescence spectrometry and machine learning algorithms

Portable X-ray fluorescence (pXRF) spectrometry is a non-destructive technique that has been successfully used to analyze different matrices. Foliar analysis is challenging because some plant nutrients cannot be detected by pXRF. Even so, the uptake interactions among nutrients which reflect different concentrations of macro- and micronutrients can be accessed via pXRF, constituting a basis to obtain predictive models of plant nutrients. The objective of this work was to compare and assess the accuracy of linear regression and non-linear models (support vector machine – SVM; and random forest – RF) to predict the actual concentration of macro- (N, P, K, Ca, Mg, and S) and micronutrients (B, Cu, Fe, Zn, and Mn) in coffee leaves. A greenhouse experiment was conducted using Hoagland and Arnon solution to obtain leaves with contrasting elemental composition. Ground and oven-dried leaf samples were analyzed via pXRF using: i) a manufactured pXRF calibration developed for general earth-materials (Geoexploration mode); ii) the Spectrometer mode with varying voltage and current (15 kV and 25 μA; 10 kV and 10 μA). The same samples were also analyzed via conventional acid digestion and quantified via inductively coupled plasma-optical emission spectroscopy (ICP-OES). The best predictions were obtained using SVM and RF algorithms, with high R2 (0.82 to 0.99) and high residual prediction deviation (RPD) (2.35 to 9.34) values. However, some elements (e.g., K, Ca, Cu, Mn) were successfully predicted using linear models (LR and MLR). Even elements not detected (N and B) by pXRF were accurately predicted using the RF model. The pXRF operational conditions influenced the performance of the models. However, by parsimony, Geoexploration mode provided data for accurate prediction of macro- and micronutrients. This comprehensive study can potentially spark further investigations into examining coffee leaves from plants cultivated under various environmental and management conditions. Additionally, the methodological framework outlined here holds promise for ongoing experimentation across diverse crops, offering a streamlined, non-invasive, eco-friendly, and rapid approach for foliar analysis.

Doped SnO2 thin films fabricated at low temperature by atomic layer deposition with a precise incorporation of niobium atoms

Nb-doped SnO2 (NTO) thin films were synthesized by atomic layer deposition technique at low temperature (100 °C). For an efficient incorporation of the Nb atoms, i.e. fine control of their amount and distribution, various supercycle ratios and precursor pulse sequences were explored. The thin film growth process studied by in-situ QCM revealed that the Nb incorporation is highly impacted by the surface nature as well as the amount of species available at the surface. This was confirmed by the actual concentration of the Nb atom incorporated inside the thin film as determined by XPS. Highly transparent thin films which transmit more than 95% of the AM1.5 global solar irradiance over a wide spectral range (300–1000 nm) were obtained. In addition, the Nb atoms influenced the optical band gap, conduction band, and valence band levels. While SnO2 thin film were too resistive, films tuned to conductive nature upon Nb incorporation with controlled concentration. Optimal incorporation level was found to be ⩽1 at.% of Nb, and carrier concentration reached up 2.5 × 1018 cm−3 for the as-deposited thin films. As a result, the high optical transparency accompanied with tuned electrical property of NTO thin films fabricated by ALD at low temperature paves the way for their integration into temperature-sensitive, nanostructured optoelectrical devices.

Effects of microplastics on typical macrobenthos in sargassum ecosystems

Recently, microplastics (MPs) have attracted extensive attention to their wide distribution and potential toxicity in ecosystems. However, there was a lack of research focused on MPs in seaweed bed ecosystems. This study investigated the distribution and toxicity of MPs in macrobenthos in Sargassum ecosystem. According to the in-situ investigation results, the abundance of MPs in the sediment was 0.9–2.3 items/g, the indoor microcosmic experiment was constructed. After exposure to MPs (0, 2, and 20 items/g) for 30 days, the abundance of MPs in macrobenthos exhibits a concentration-dependent increase. However, there was no significant bioaccumulation of MPs at the trophic level. The indoor toxicity test revealed that MPs induced oxidative stress and altered intestinal microflora composition in macrobenthos, even at actual environmental concentrations (2 items/g). It may result in a perturbation of the organism's homeostatic equilibrium. High-concentration (20 items/g) MPs had a greater impact on alkaline phosphatase (AKP) in Mollusks. The increase in AKP activity could be indicative of an adaptive mechanism in some macrobenthos while the decline in AKP activity might signal a decrease in their survival. These results elucidated the fate of MPs in ecosystem and the ecological risks of MPs to large benthic animals on model environmental conditions.

Technical note: Quantifying radionuclide residues in hospital wastewater: A case study on [131I]I and [177mLu]Lu/[177Lu]Lu.

Historically, [131I]I has been a common isotope in radionuclide therapy, with [177Lu]Lu-labelled radiopharmaceuticals now seeing a surge in use. These can include no-carrier-added or carrier-added [177Lu]Lu with slight impurities of [177mLu]Lu with a significantly longer half-life than [131I]I. Wastewater from therapy wards can contain a mixture of these radioisotopes. In some countries, national regulations require wastewater to be stored in dedicated systems before it is discharged into the public sewage system. To fulfill legal requirements, the nuclide specific activity concentration must be verified. We evaluate a method for determining the activity concentration of [177mLu]Lu /[177Lu]Lu at equilibrium and [131I]I in pure and mixed samples in order to prove that the determined values are reliably below the limits for release. We analysed the emitted energy spectrum of 1L samples with a wastewater counter using an energy window-based approach by evaluating measurements from two different time points. Based on the law of decay and the time and energy-dependent measured values, equation systems were set up to calculate the count rates for [131I]I and [177mLu]Lu, which were converted into activity concentration using calibration factors. There is strong linear correlation between the nominal and determined activity concentrations (correlation coefficients R=0.99; coefficient of determinations R2=0.99). We underestimate the actual activity concentration by a median of -1.4% for [177mLu]Lu and overestimate the activity concentration for [131I]I by a median of 7.1%. We show that an undercut of the clearance levels for material release is measurable. We analyse and determine activity concentrations of mixed samples consisting of [131I]I and [177mLu]Lu/[177Lu]Lu in equilibrium. The method is simple to implement using a conventional wastewater counter, however with a slightly increased effort, as two samples and measurements are required. The methodology can be adapted for the analysis of other nuclide mixtures.

Toxic effects of a single sulfonamide antibiotic on two indicator organisms

The widespread use of antibiotics leads to more and more serious pollution of antibiotics in the environment, which has become a global ecological environment problem. Antibiotic pollution will affect the normal life activities of organisms and threaten human health through the food chain. In order to investigate the toxic effects of antibiotic pollution on different indicator organisms, Scenedesmus obliquus and Vibrio qinghaiensis sp-Q67 were used as indicator organisms. Eight widely used sulfonamides antibiotics (SAs), namely, sulfapyridine (SPY), sulfamethazine (SMR), sulfadimethazine (SM2), sulfamethoxazine (SMP), sulfamethoxazole (SMZ), sulfaquinoxaline (SQ), sulfamethoxine (SMM), sulfamethoxine (SMM), and sulfamethoxine (SMM), were studied by microplate toxicity test. The growth inhibition toxicity of sulfamide chloropyrazine sodium (2-SPZ) and its binary mixture to Cyanobacteria obliqua (96h) and Vibrio Qingqingensis Q67 (15min acute and 1h chronic); Based on the actual environmental concentration of SAs in Huixian wetland of Guilin, two groups of six-element mixtures were designed to study their combined toxicity to two different indicator organisms.

To Dilute or Not to Dilute: Nominal Titer Dosing for Genetic Medicines.

Recombinant adeno-associated virus (AAV) has become a popular platform for many gene therapy applications. The strength of AAV-based products is a critical quality attribute that affects the efficacy of the drug and is measured as the concentration of vector genomes, or physical titer. Because the dosing of patients is based on the titer measurement, it is critical for manufacturers to ensure that the measured titer of the drug product is close to the actual concentration of the batch. Historically, dosing calculations have been performed using the measured titer, which is reported on the drug product label. However, due to recent regulatory guidance, sponsors are now expected to label the drug product with nominal or "target" titer. This new expectation for gene therapy products can pose a challenge in the presence of process and analytical variability. In particular, the manufacturer must decide if a dilution of the drug substance is warranted at the drug product stage to bring the strength in line with the nominal value. In this paper, we present two straightforward statistical methods to aid the manufacturer in the dilution decision. These approaches use the understanding of process and analytical variability to compute probabilities of achieving the desired drug product titer. We also provide an approach for determining an optimal assay replication strategy for achieving the desired probability of meeting drug product release specifications.