Control Levels Research Articles

Enhancing response inhibition behavior through tDCS intervention in college students with smartphone addiction

Smartphone addiction, emerging from excessive use of smartphones, poses a challenge to inhibitory control functions within society. This research employed transcranial direct current stimulation (tDCS) as an intervention alongside the stop signal task (SST) to explore behavioral distinctions between individuals with smartphone addiction and a non-addicted control group, focusing on the efficacy of tDCS intervention. The participant cohort comprised 80 individuals, divided into an addiction group (39 participants, with 19 receiving active tDCS and 20 receiving sham tDCS) and a control group (41 participants, with 20 receiving active tDCS and 21 receiving sham tDCS), with anodal stimulation applied over the right dorsolateral prefrontal cortex (dlPFC) and cathodal placement over the left arm. The findings indicate that university students struggling with smartphone addiction exhibit reduced inhibitory control compared to their non-addicted peers, while maintaining similar levels of general cognitive control. Remarkably, tDCS interventions were observed to enhance inhibitory control in both groups. Although the improvement in the addiction group appeared more pronounced numerically than in the control group, no significant interaction with group was noted. However, a higher percentage of participants in the smartphone addiction (SA) group exhibited enhanced response inhibition under active tDCS. This study demonstrates the inhibitory control deficits in individuals addicted to smartphones and underscores the potential of tDCS in enhancing response inhibition. It provides a valuable reference for future tDCS research targeting smartphone addiction and highlights the importance of developing healthier smartphone usage habits.

Association between physical activity and inhibitory control in children

ABSTRACT Evidence supports a positive association between physical activity and executive function in children. How physical activity performed in different contexts associates with inhibitory control remains unclear. This cross-sectional study examined associations between inhibitory control and four measures of physical activity (activity during PE, breaktime, outside school and in sport) in 340 primary school children (8.6 ± 1.6 years old, n = 197 female). In models adjusted for sex, age, adiposity and SES, greater activity during breaktime was associated with fewer commission errors in the sustained attention (β =−0.10, 95%CI: −0.19, −2.95e-03, p = .04) and inhibition tasks (β = −0.06, 95%CI: −0.11, −9.33e-03, p = .02). These results suggest that unsupervised active play at school is associated with higher levels of inhibitory control.

Halotolerant Microorganism-Based Soil Conditioner Application Improved the Soil Properties, Yield, Quality and Starch Characteristics of Hybrid Rice under Higher Saline Conditions.

Soil salinity represents a significant factor affecting agricultural productivity and crop quality. The present study was conducted to investigate the effects of soil conditioner (SC) comprising halotolerant microorganisms on the soil fertility, yield, rice quality, and the physicochemical and structural properties of starch in hybrid rice under saline conditions. The experimental treatments were composed of two high-quality hybrid rice varieties, i.e., 'Y Liangyou 957' (YLY957) and Jing Liangyou 534 (JLY534), and two soil amendment treatments, i.e., the application of SC at control levels and 2250 kg hm-2, or 'CK and SC', respectively. The crop was subjected to a mixture of fresh and sea water (EC 11 dS/m). The results demonstrated that the application of SC significantly enhanced the rice yield under salt stress conditions owing to an increase in the number of grains per panicle. Furthermore, SC was found to be effective in improving the organic matter and soil nutrient content. Furthermore, the application of SC resulted in an improvement in antioxidant defense, higher leaf SPAD values, and greater crop biomass, as well as the translocation of photo-assimilates at the heading stage. The application of SC not only improved the milling and appearance quality but also enhanced the taste value of rice by increasing the amylose and reducing the protein content. Furthermore, the application of SC also decreased the indentations on the surfaces of starch granules and cracks on the edges of the granules. The rice varieties subjected to SC exhibited excellent pasting properties, characterized by reduced proportions of amylopectin short chains and a lower gelatinization temperature and enthalpy of gelatinization. Overall, these findings serve to reinforce the efficacy of soil conditioner as a valuable tool to improve rice productivity and sustainability with improved rice grain quality under saline conditions.

Dual‐Modal Stretchable Sensing Patches for In Situ Monitoring of Electromyography and Acoustic Myography

AbstractElectromyography (EMG) and acoustic myography (AMG) play crucial roles in assessing muscle function, providing valuable insights into neural control, muscle activation, and fatigue levels. However, the current landscape reveals a gap in dual‐modal stretchable sensing patches, highlighting the need for comfortable and wearable solutions in the field of in situ monitoring of synchronous EMG and AMG sensing. In this work, a dual‐modal stretchable patch (DMSP) is developed that fully integrates a multi‐channel EMG electrode with AMG sensors. It possesses stable electromechanical properties even at strains exceeding 200%. With an overall modulus of under 40 kPa and a skin adhesion force surpassing 30 N m−1, the DMSP exhibits exceptional durability, enduring 1000 stretching cycles. The DMSP enables in situ simultaneous monitoring of EMG and AMG signals from sternocleidomastoid muscle during neck rotation where the mechanical strain reaches up to 30%. The DMSP proves instrumental in characterizing muscle activity, facilitating in‐depth research on muscle movement, and thus enhancing clinical outcomes in rehabilitation medicine and physical therapy.

Increasing salinity sequentially induces salt tolerance responses in Szarvasi-1 energy grass

Soil salinity causes severe physiological disorders, decline in biomass, and crop production worldwide becoming more critical with global climate change. Consequently, salt-tolerant varieties received major focus in all sectors of agriculture. Biomass plants such as Szarvasi-1 energy grass (Elymus elongatus subsp. ponticus cv. Szarvasi-1) may play an important role in energy production if they are tolerant to environmental stresses. In this study, Szarvasi-1 energy grass has been investigated to reveal its tolerance to 50–200 mM NaCl in hydroponics. Significant decline in stomatal conductance appeared at 100 mM NaCl treatment but fresh and dry weight and the maximal quantum efficiency of PSII decreased only at 200 mM NaCl. Relative water content and total chlorophyll concentration did not change compared to the control. Leaf water potential was maintained at the control level for one week NaCl exposure, decrease became significant only after two weeks. Malondialdehyde concentration did not refer to oxidative stress. In the element composition of the plants, remarkable increase was found only for Mo whereas Ca, K, S, P, Mn decreased compared to the control. K to Na ratio remained higher than one in the shoot even at 200 mM NaCl. Salt treatment caused temporal and concentration-dependent changes in the expression of genes in the phenylpropanoid pathway, Na transport, photosynthesis, and cellular protection and repair. Szarvasi-1 was found to be fairly tolerant to NaCl which induced a sequential response switching on vacuolar compartmentalization at 50 mM, Na efflux at 100 mM, and cellular protection and repair at 200 mM.

Relationship between glycaemic control and frailty in older Chinese patients: The mediating role of diabetes distress.

This study aimed to investigate the effects of glycaemic control and diabetes distress on frailty in older Chinese patients with diabetes, and to explore the mediating role of diabetes distress between glycaemic control and frailty. This is a descriptive, cross-sectional study. A total of 209 older patients with diabetes were recruited from a teaching hospital in Zhejiang Province. Data were collected from February to September 2022. A self-designed questionnaire was used to collect demographic and disease-related data. The Fried Scale and Diabetes Distress Scale were employed to assess frailty and diabetes distress, respectively The bootstrap method was used to examine the mediating effects of diabetes distress on glycaemic control and frailty. The STROBE checklist was adhered to in the reporting of this study (see details in File S1). The findings indicated a positive correlation between the level of glycaemic control and frailty, as well as between diabetes distress and frailty. Furthermore, diabetes distress was found to play a complete mediating role between glycaemic control and frailty. The study findings highlight the relationship between glycaemic control, diabetes distress and frailty offering a valuable reference for enhancing the management of frailty in older patients with diabetes. This study emphasizes the significance of managing glycaemic control and diabetes distress in older patients with diabetes to prevent frailty, and may contribute for healthcare professionals to developing effective measures to improve the frailty of older diabetic patients in clinical settings. This study was conducted with the participation of older patients with diabetes who contributed data by completing study questionnaires and undergoing physical assessments.

Investigating the modulation of the endocannabinoid system by probiotic Lactiplantibacillus plantarum IMC513 in a zebrafish model of di-n-hexyl phthalate exposure

Environmental pollutants used as plasticizers in food packaging and in thousands of everyday products have become harmful for their impact on human health. Among them, phthalates, recognized as emerging endocrine disruptors (EDs) can induce toxic effects leading to different health disorders. Only few studies evaluated the effects of di-n-hexyl phthalate (DnHP) in in vivo models and no studies have been conducted to investigate the effect of DnHP on the endocannabinoid system (ECS), one of the majors signaling pathways involved in the microbiota–gut–brain axis. Due to the current relevance of probiotic bacteria as beneficial dietary interventions, the present study was aimed at evaluating the potential neuroprotective impact of daily administration of Lactiplantibacillus (Lpb.) plantarum IMC513 on zebrafish adults exposed to DnHP, with a focus on ECS modulation. Gene expression analysis revealed a promising protective role of probiotic through the restoration of ECS genes expression to the control level, in the brain of zebrafish daily exposed to DnHP. In addition, the levels of main endocannabinoids were also modulated. These findings confirm the potential ability of probiotics to interact at central level by modulating the ECS, suggesting the use of probiotics as innovative dietary strategy to counteract alterations by EDs exposure.

A single intravenous reelin injection restores corticosterone-induced neurochemical and behavioral alterations in dams during the post-partum period.

Treatment with the synaptic plasticity protein reelin has rapid antidepressant-like effects in adult corticosterone (CORT)-induced depressed rats, whether administered repeatedly or acutely. However, these effects remain unexplored in the context of post-partum depression (PPD). This study investigated the antidepressant-like effect of a single injection of reelin in a CORT-induced model of PPD. Long-Evans female dams received either daily subcutaneous CORT (40 mg/kg) or saline injections (controls) from the post-partum day (PD) 2 to 22, and on PD22 were treated with a single intravenous reelin (3 μg) or vehicle injection. Reelin treatment fully normalized to control levels the CORT-induced increase in Forced Swim Test (FST) immobility and the decrease in reelin-positive cells in the subgranular zone of the intermediate hippocampus. It also increased the number of oxytocin-positive cells in the paraventricular nucleus (PVN), the number of reelin-positive cells in the dorsal and ventral hippocampus, and the dendritic complexity of newborn neurons in the intermediate hippocampus, causing a partial recovery compared to controls. None of these changes were associated with fluctuations in estrogen levels measured peripherally. This study brings new insights into the putative antidepressant-like effect of peripherally administered reelin in an animal model of PPD. Future studies should be conducted to investigate these effects on a dose-response paradigm and to further elucidate the mechanisms underlying the antidepressant-like effects of reelin.

Improvement of legal guarantees of legality in the service activity of administrative courts in Ukraine

The scientific article identifies the peculiarities of improving the service activity of administrative courts in Ukraine. Special guarantees include legal (legal) guarantees of legality of service activities of administrative courts in Ukraine, which represent specific legal means and internal legal mechanisms, which are a real embodiment of legality in the legal sphere. Legal guarantees of the legality of service activities of administrative courts in Ukraine include: completeness and effectiveness of legal norms; a high level of control and supervision over the implementation of legality; quality activity of competent authorities to ensure legality; improvement and improvement of legal practice; effectiveness of measures of legal responsibility. The author has highlighted the areas of effectiveness of the implementation of legal guarantees of the service activity of administrative courts in Ukraine, namely: to improve the administrative and legal regulation and the mechanism of control on the part of public administration subjects through the delimitation of their competence; the procedure for exercising the powers of state authorities and local self-government bodies regarding control in service activities; to develop and adopt the Law of Ukraine «On Judicial Services», in which to define an exhaustive list of government entities that would carry out control in this area, their powers, forms and procedures of such activity, methods, methods of implementation and responsibility in case of abuse of control, etc. ; strengthening public control and creating effective feedback with civil society organizations through the development and implementation of the project «Proliferation of non-state monitoring of service activities of administrative courts in Ukraine», which will improve the quality of the provision of court services by relevant entities of public administration, etc.

High mobility group box1 (HMGB1) is a potential disease biomarker in cell and mouse models of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a progressive muscle wasting disorder affecting 1:3500 male births and is associated with myofiber degeneration, regeneration, and inflammation. Glucocorticoid treatments have been the standard of care due to immunomodulatory/immunosuppressive properties but novel genetic approaches, including exon skipping and gene replacement therapy, are currently being developed. The identification of additional biomarkers to assess DMD-related inflammatory responses and the potential efficacy of these therapeutic approaches are thus of critical importance. The current study uses RNA sequencing of skeletal muscle from two mdx mouse models to identify high mobility group box1 (HMGB1) as a candidate biomarker potentially contributing to DMD-related inflammation. HMGB1 protein content was increased in a human iPSC-derived skeletal myocyte model of DMD and microdystrophin treatment decreased HMGB1 back to control levels. In vivo, HMGB1 protein levels were increased in vehicle treated B10-mdx skeletal muscle compared to B10-WT and significantly decreased in B10-mdx animals treated with adeno-associated virus (AAV)-microdystrophin. However, HMGB1 protein levels were not increased in D2-mdx skeletal muscle compared to D2-WT, demonstrating a strain-specific difference in DMD-related immunopathology.

Homeostatic Regulation of Spike Rate within Bursts in Two Distinct Preparations.

Homeostatic plasticity represents a set of mechanisms thought to stabilize some function of neural activity. Here, we identified the specific features of cellular or network activity that were maintained after the perturbation of GABAergic blockade in two different systems: mouse cortical neuronal cultures where GABA is inhibitory and motoneurons in the isolated embryonic chick spinal cord where GABA is excitatory (males and females combined in both systems). We conducted a comprehensive analysis of various spiking activity characteristics following GABAergic blockade. We observed significant variability in many features after blocking GABAA receptors (e.g., burst frequency, burst duration, overall spike frequency in culture). These results are consistent with the idea that neuronal networks achieve activity goals using different strategies (degeneracy). On the other hand, some features were consistently altered after receptor blockade in the spinal cord preparation (e.g., overall spike frequency). Regardless, these features did not express strong homeostatic recoveries when tracking individual preparations over time. One feature showed a consistent change and homeostatic recovery following GABAA receptor block. We found that spike rate within a burst (SRWB) increased after receptor block in both the spinal cord preparation and cortical cultures and then returned to baseline within hours. These changes in SRWB occurred at both single cell and population levels. Our findings indicate that the network prioritizes the burst spike rate, which appears to be a variable under tight homeostatic regulation. The result is consistent with the idea that networks can maintain an appropriate behavioral response in the face of challenges.

Parental SES and family support as predictors of educational level: Testing the buffering effect of effortful control and peer support.

Exposure to family risk factors increases adolescents' chances of attaining a lower educational level. However, some adolescents attain a high educational level despite being exposed to family risk factors such as a lower parental socioeconomic status (SES) or receiving less family support. Using data from the Dutch TRAILS cohort study (NT1 = 2175; Mage = 11.1, SD = 0.55, 50.8% female), we investigated if higher levels of effortful control and peer support can buffer against the negative effects of a lower parental SES and less family support on educational level. Two multinomial logistic regressions were performed (from early to mid-adolescence and from mid-adolescence to young adulthood) with post hoc tests to contrast four ordinal educational levels: practical vocational, theoretical vocational, higher general, and (pre-)university. Adolescents with a higher parental SES were consistently more likely to end up at a higher educational level, but family support was hardly associated with educational level. Neither effortful control nor peer support buffered the associations of parental SES and family support with educational level. Effortful control did have a positive direct (compensatory) effect on the educational level. We conclude that other individual competencies or more structural changes may be more helpful buffers for reducing socioeconomic inequalities in educational attainment.

Constructing a medium-entropy and A-site deficient perovskite oxide for efficient electrocatalytic oxygen evolution

Electrochemical water splitting has emerged as a promising alternative to traditional fossil fuels, providing an efficient and eco-friendly pathway to generate clean hydrogen energy. While the development of high-entropy oxides (HEOs) has introduced a paradigm of integrating multiple metal elements, medium-entropy oxides (MEOs) have been recognized as a more advantageous option partly due to the more controlled entropy levels in MEOs, allowing for a finely-tuned balance between compositional complexity and functional optimization. Building on this concept, this study introduces a medium-entropy perovskite oxide (Ba0.9La0.1)0.9Co0.6Fe0.2Ni0.2O3-δ (BLCFN-0.9), with A-site deficiency for optimizing oxygen evolution reaction (OER). Comprehensive analysis reveals that BLCFN-0.9 demonstrates superior OER activity with an impressively low overpotential of 294 mV to deliver a current density of 10 mA cm−2 in an alkaline electrolyte, outperforming other state-of-the-art perovskite oxide electrocatalysts. Notably, the BLCFN-0.9 electrocatalyst achieves the robust performance stability, maintaining a consistently low potential over 30 h. This study sheds light on the potential of medium-entropy perovskite oxides for advancing OER efficiency, opening a new avenue to the evolution of electrocatalysis through strategic material design.

Organ chips with integrated multifunctional sensors enable continuous metabolic monitoring at controlled oxygen levels

Despite remarkable advances in Organ-on-a-chip (Organ Chip) microfluidic culture technology, recreating tissue-relevant physiological conditions, such as the region-specific oxygen concentrations, remains a formidable technical challenge, and analysis of tissue functions is commonly carried out using one analytical technique at a time. Here, we describe two-channel Organ Chip microfluidic devices fabricated from polydimethylsiloxane and gas impermeable polycarbonate materials that are integrated with multiple sensors, mounted on a printed circuit board and operated using a commercially available Organ Chip culture instrument. The novelty of this system is that it enables the recreation of physiologically relevant tissue-tissue interfaces and oxygen tension as well as non-invasive continuous measurement of transepithelial electrical resistance, oxygen concentration and pH, combined with simultaneous analysis of cellular metabolic activity (ATP/ADP ratio), cell morphology, and tissue phenotype. We demonstrate the reliable and reproducible functionality of this system in living human Gut and Liver Chip cultures. Changes in tissue barrier function and oxygen tension along with their functional and metabolic responses to chemical stimuli (e.g., calcium chelation, oligomycin) were continuously and noninvasively monitored on-chip for up to 23 days. A physiologically relevant microaerobic microenvironment that supports co-culture of human intestinal cells with living Lactococcus lactis bacteria also was demonstrated in the Gut Chip. The integration of multi-functional sensors into Organ Chips provides a robust and scalable platform for the simultaneous, continuous, and non-invasive monitoring of multiple physiological functions that can significantly enhance the comprehensive and reliable evaluation of engineered tissues in Organ Chip models in basic research, preclinical modeling, and drug development.

Ribozyme-Mediated Gene-Fragment Complementation for Nondestructive Reporting of DNA Transfer within Soil.

Enzymes that produce volatile metabolites can be coded into genetic circuits to report nondisruptively on microbial behaviors in hard-to-image soils. However, these enzyme reporters remain challenging to apply in gene transfer studies due to leaky off states that can lead to false positives. To overcome this problem, we designed a reporter that uses ribozyme-mediated gene-fragment complementation of a methyl halide transferase (MHT) to regulate the synthesis of methyl halide gases. We split the mht gene into two nonfunctional fragments and attached these to a pair of splicing ribozyme fragments. While the individual mht-ribozyme fragments did not produce methyl halides when transcribed alone in Escherichia coli, coexpression resulted in a spliced transcript that translated the MHT reporter. When cells containing one mht-ribozyme fragment transcribed from a mobile plasmid were mixed with cells that transcribed the second mht-ribozyme fragment, methyl halides were only detected following rare conjugation events. When conjugation was performed in soil, it led to a 16-fold increase in methyl halides in the soil headspace. These findings show how ribozyme-mediated gene-fragment complementation can achieve tight control of protein reporter production, a level of control that will be critical for monitoring the effects of soil conditions on gene transfer and the fidelity of biocontainment measures developed for environmental applications.

LPG 18:0 is a general biomarker of asthma and inhibits the differentiation and function of regulatory T cells.

The diagnosis, severity assessment, and development of therapeutic strategies for asthma are crucial aspects of disease management. Since biomarkers are reliable tools in disease management, we aimed to identify and explore asthma-associated biomarkers and investigate their mechanisms. Lipidomics was used to profile serum glycerophospholipids in asthmatic patients and controls. The absolute concentration of lysophosphatidylglycerol (LPG) 18:0 was quantified in various asthma subtypes. Mouse asthma models were used to confirm its potential as a biomarker and investigate its mechanisms in vivo. The effects of LPG 18:0 on CD4+ T cell differentiation, proliferation, and apoptosis were assessed in vitro by flow cytometry, while mitochondrial dysfunction was evaluated through mitochondrial membrane potential, reactive oxygen species, and ATP production measurements. The intracellular mechanism of LPG 18:0 in Tregs was investigated using small molecule inhibitors. The serum glycerophospholipid profile varied between asthmatic patients and control group, with LPG 18:0 levels being notably higher in asthmatic patients, correlating with asthma severity and control level. In vivo and in vitro studies revealed that LPG18:0 impaired naïve CD4+ T cell differentiation into Tregs and compromised their suppressive function. Further investigation demonstrated that LPG18:0 treatment reduced the FOXP3 protein level via SIRT1-mediated deacetylation during Treg differentiation. This study identifies that serum levels of LPG 18:0 are generally elevated in asthmatics and serve as a biomarker for asthma. LPG 18:0 impairs Treg function via the NAD+/SIRT1/FOXP3 pathway. Our research reveals the potential of LPG18:0 as a biomarker for asthma, elucidating its role in asthma diagnosis and treatment.

Quantitative analysis of nonsteroidal anti-inflammatory drugs in dried blood spot from mountain ultra-trail runners. Contribution of pharmacokinetic models for the interpretation of the results.

Monitoring of drug use in athletes is of interest both for health and competition-related issues. Considering the advantages of Dried Blood Sampling (low invasiveness, easy sampling, long term storage), we have validated a quantitative LC-MS/HRMS method for the screening of 16 nonsteroidal anti-inflammatory drugs. For all drugs, accuracy and imprecision were within 15% for the 3 levels of quality control and lower than 20% for the lower limit of quantification. Application was performed from samples obtained for Ultra-Trail du Mont-Blanc® 2021 and 2022. A focus on ibuprofen and its metabolites (hydroxyibuprofen, carboxyibuprofen, ibuprofen glucuronide and hydroxyibuprofen glucuronide) was made because the results showed that it was the most detected nonsteroidal anti-inflammatory drug. Further, an interpretation of the ibuprofen concentrations was proposed either from experimental data obtained after an intake of ibuprofen by 10 control subjects, or from a pharmacokinetic modelling and simulations. Depending on the analytical performances of the method, we proposed possible detection windows for ibuprofen in runners. The pharmacokinetic model made it possible to consider two scenarios with and without modification of the total clearance of ibuprofen linked to a modification of the pharmacokinetics of the drugs due to the practice of a long and intense physical activity.

In situ X-ray diffraction and thermal simulation of material extrusion additive manufacturing of polymer

Material extrusion additive manufacturing (AM) has gradually become a dominant technology for the fabrication of complex-designed thermoplastic polymers that require a higher level of control over the morphological and mechanical properties. The polymer internal crystal structure formed during the AM process can present significant impacts on the mechanical properties of the individual filaments, as well as the whole structure. Currently, limited details are known about the crystal structure evolution during the material extrusion AM processes of polymers. A novel in situ synchrotron X-ray diffraction (XRD) experimental configuration was developed enabling us to capture the material evolution data throughout the extrusion AM process. The in situ time-resolved data was analysed to reveal nucleation and crystallization sequences during the continuous deposition, with the aid of both complimentary numerical simulations and post-process (ex situ) characterisations. The thermal simulations supported the prediction of the filament temperature profile over time and location during the AM process, while ex situ characterisations validated the correlation between polymer crystallinity (resulting from printing parameters) and corresponding mechanical properties. The results obtained from varied process parameters suggest that the processing temperature has a dominant influence on the crystal microstructure evolution compared to the deposition velocity. A lower processing temperature just above the melting temperature permitted favourable crystallization conditions. The overall analysis demonstrated prospects for enhancing polymer AM, to engineering mechanically hierarchical structures through correlative investigations.

Locus of control over global mine production– developments between 1985 and 2018 against a historical background

AbstractIt is a well-known fact that mine production has shifted from the industrialised countries of Europe, North America and Japan to emerging economies in Latin America, Africa and Asia and to Australia since the mid-20th century. The lack of self-sufficiency or high import dependence, in particular of the so-called critical metals, has become an issue of great political concern in these industrialised countries over the past 15 years. This study of six metals, cobalt, copper, iron ore, lithium, manganese and rare earths, contrasts this picture of geographical location of production with an analysis of where the control over mine production around the world is based, which we call the locus of control. Production might have moved out of the industrialised countries but control over production by companies based in the industrialised countries remains and has even increased between 1985 and 2018. We measure control as share of the total value of the production of the six metals. European transnational mining companies have increased their control from 14 to 18% while mining companies based in North America have lost control, a decline from 13 to 8%. When Australian companies, that have more than tripled their control in the same period, are added, control by the industrialised countries has increased to 44% of these six metals. Companies based in Latin America, Africa and Asia excluding China, taken together have maintained their control level, roughly a third of the total value of the six metals. Inside this group of countries African share has dwindled from 12 to 3% while Asian companies have more than doubled their share from 5 to 12%. Control by mining companies based in the republics of the former Soviet Union have been reduced from 25 to 7% while in the same period Chinese companies’ control has doubled from 6 to 12% of the total value of these six metals. Countries in Asia (excluding China) together with Latin American and African countries produce 51% of these six metals measured by the value at the mine stage. However, companies based in these countries control not more than 33% of the production.

Biodistribution of cerium dioxide and titanium dioxide nanomaterials in rats after single and repeated inhalation exposures

BackgroundPhysiologically based kinetic models facilitate the safety assessment of inhaled engineered nanomaterials (ENMs). To develop these models, high quality datasets on well-characterized ENMs are needed. However, there are at present, several data gaps in the systemic availability of poorly soluble particles after inhalation. The aim of the present study was therefore to acquire two comparable datasets to parametrize a physiologically-based kinetic model.MethodRats were exposed to cerium dioxide (CeO2, 28.4 ± 10.4 nm) and titanium dioxide (TiO2, 21.6 ± 1.5 nm) ENMs in a single nose-only exposure to 20 mg/m3 or a repeated exposure of 2 × 5 days to 5 mg/m3. Different dose levels were obtained by varying the exposure time for 30 min, 2 or 6 h per day. The content of cerium or titanium in three compartments of the lung (tissue, epithelial lining fluid and freely moving cells), mediastinal lymph nodes, liver, spleen, kidney, blood and excreta was measured by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) at various time points post-exposure. As biodistribution is best studied at sub-toxic dose levels, lactate dehydrogenase (LDH), total protein, total cell numbers and differential cell counts were determined in bronchoalveolar lavage fluid (BALF).ResultsAlthough similar lung deposited doses were obtained for both materials, exposure to CeO2 induced persistent inflammation indicated by neutrophil granulocytes influx and exhibited an increased lung elimination half-time, while exposure to TiO2 did not. The lavaged lung tissue contained the highest metal concentration compared to the lavage fluid and cells in the lavage fluid for both materials. Increased cerium concentrations above control levels in secondary organs such as lymph nodes, liver, spleen, kidney, urine and faeces were detected, while for titanium this was found in lymph nodes and liver after repeated exposure and in blood and faeces after a single exposure. Conclusion: We have provided insight in the distribution kinetics of these two ENMs based on experimental data and modelling. The study design allows extrapolation at different dose-levels and study durations. Despite equal dose levels of both ENMs, we observed different distribution patterns, that, in part may be explained by subtle differences in biological responses in the lung.