Regeneration Method Research Articles

Fate of trimethoprim, sulfamethoxazole and caffeine after hydrothermal regeneration of activated carbon

Emerging contaminants are found in all parts of our environment. Adsorption of these contaminants by activated carbon in water treatment plants is well-known; however, a problem resides in the handling of the spent adsorbents. As current regenerative technologies are expensive, the adsorbents are often destructed or landfilled. Here, we examine a novel regeneration method for the used adsorbents with subcritical water – i.e., hydrothermal treatment. The degradation of three well-known emerging contaminants – caffeine, trimethoprim and sulfamethoxazole – was studied with regard to processing temperature (160–280 °C), concentration (2 and 20 mg/L), and the impact of adsorbents. In addition to trimethoprim in the mix at 20 mg/L, the other contaminants were entirely degraded at 280 °C. To obtain insight into transformation products formed during hydrothermal regeneration, we performed non-target and targeted analyses with LC-MS-QTOF using two types of columns, C18 and ZIC-HILIC. This approach ensured a wide range of hydrophilicities. Results showed more transformation products for trimethoprim (20) compared to sulfamethoxazole and caffeine (4). To assess the regeneration efficiencies of the activated carbons, we conducted three cycles of regeneration at 280 °C and between 61 and 120 % degradation was achieved. Moreover, only two transformation products were detected and readsorbed on the adsorbent after regeneration. Hydrothermal regeneration efficiently degraded the target emerging contaminants, suggesting a potential approach for enabling alternative, sequential uses for regenerated activated carbon.

Enhancing Methylene Blue Dye Removal using pyrolyzed Mytella falcata Shells: Characterization, Kinetics, Isotherm, and Regeneration through Photolysis and Peroxidation.

The potential of pyrolyzed Mytella falcata shells as an adsorbent for removing methylene blue dye molecules from aqueous solutions was investigated. The study found that the adsorbent produced at 600 °C of pyrolysis temperature, with an adsorbent mass of 0.5 g, particle diameter of 0.297-0.149 mm, and pH 12.0, demonstrated the highest dye molecule removal efficiency of 82.41%. The material's porosity was observed through scanning electron microscopy, which is favorable for adsorption, while Fourier-transform infrared spectroscopy and X-Ray diffraction analysis analyses confirmed the presence of calcium carbonate in the crystalline phases. The pseudo-second order model was found to be the best fit for the data, suggesting that the adsorption mechanism involves two steps: external diffusion and diffusion via the solid pores. The Redlich-Peterson isotherm model better represented the equilibrium data, and the methylene blue adsorption was found to be spontaneous, favorable, and endothermic. The hydrogen peroxide with UV oxidation was found to be the most efficient method of regeneration, with a regeneration percentage of 63% achieved using 600 mmol.L-1 of oxidizing agents. The results suggest that pyrolyzed Mytella falcata shells could serve as an ecologically viable adsorbent alternative, reducing the amount of waste produced in the local environment and at the same time removing pollutants from the water. The material's adsorption capacity remained almost constant in the first adsorption-oxidation cycles, indicating its potential for repeated use.

Let-7a promotes periodontal bone regeneration of bone marrow mesenchymal stem cell aggregates via the Fas/FasL-autophagy pathway.

Periodontal bone regeneration using bone marrow mesenchymal stem cell (BMMSC) transplantation is a promising method; however, the method for osteogenic differentiation of BMMSCs needs to be improved. In this research, we sought to identify the roles of let-7a in the osteogenesis of BMMSCs and to provide a potential method for periodontal bone regeneration. Our previous study revealed that Fas/FasL is a target of let-7a. In this study, we demonstrated that let-7a overexpression significantly enhanced BMMSC-CAs osteogenesis both invitro and invivo. Mechanistically, upregulation of Fas/FasL using the rfas/rfaslg plasmid obstructed the osteogenesis of BMMSCs by inhibiting autophagy. Furthermore, we confirmed that overexpression of let-7a activated autophagy and alleviated the inhibited osteogenesis by the autophagy inhibitor 3-MA and the rfas/rfaslg plasmid of BMMSCs. In general, our findings showed that let-7a promoted the osteogenesis of BMMSCs through the Fas/FasL-autophagy pathway, suggesting that the application of let-7a in BMMSC-CAs based periodontal bone regeneration could be a promising strategy.

Efficient Co‐Cu/MS Catalyst from the Sequential Adsorption and Carbonization of Melamine Foam for the Selective Oxidation of 5‐Hydroxymethylfurfural (HMF)

AbstractPolyethylenefuranoate, a suitable alternative for polyethylene terephthalate, can be synthesized from biomass‐derived 2,5‐furandicarboxylic acid (FDCA), which is obtained via the selective oxidation of 5‐hydroxymethylfurfural (HMF) over noble or non‐noble metal oxide catalysts. However, the FDCA yields using non‐noble metal catalysts can be improved. Hence, in this study, we developed a series of Co‐ and Cu‐embedded melamine sponge (MS)‐derived carbon catalysts (xCo‐Cu/MS) for HMF oxidation, wherein Co and Cu oxides with different Co : Cu ratios were embedded in carbonized MS. The metals were adsorbed on the MS, followed by carbonization. This strategy allowed the uniform distribution of metal clusters in the carbon texture, which enhanced the catalytic activity for HMF conversion and improved the FDCA yield. The good distribution and small crystal size of Co3O4 significantly increased the active surface area, enhancing the catalytic activity. Compared to Co‐Cu/MS catalysts, the 4Co‐Cu/activated carbon catalyst synthesized via impregnation afforded the maximum FDCA yield (93 %) with 100 % HMF conversion at 170 °C and 7 h. Moreover, oxidative regeneration using H2O2 proved to be the best regeneration method for the MS catalysts, with only a 5 % decrease in the FDCA yield after three cycles.

Organic Eutectic Salts‐Assisted Direct Lithium Regeneration for Extremely Low State of Health Ni‐Rich Cathodes

AbstractCurrently, the concept of direct regeneration has garnered considerable attention from the public due to its minimal environmental impact, high economic value, and stable performance of recycled materials. In this study, an organic lithium salt‐assisted eutectic salts direct regeneration (OAER) is proposed for replenishing lithium in an extremely low state of health Ni‐rich cathode (Low SOH NCM). The OAER method capitalizes on the favorable inherent properties of eutectic salts; moreover, the reactions of organic lithium salt create an oxidation environment and vacancies. By employing OAER, Low SOH NCM are able to be recovered, which originally has a capacity of only 46.8 mAh g−1, to 155.5 mAh g−1 with a capacity retention of 95.6% after 100 cycles. Notably, this performance is substantially higher than that achieved through conventional and purely eutectic salt regeneration methods and even slightly surpasses the current commercial NCM material. Considering the economic and environmental benefits of the OAER approach, it demonstrates potential for direct regeneration of Low SOH NCM and exhibits competitiveness for industrial applications.

Dental Tissue Engineering by Neural Differentiation of Dental Stem Cells and Nano-systems: A Review

Background: Pulpitis is a pulpal inflammation. It generally occurs when there is inflammation within a tooth as a result of anything like grinding or decay. After dental inflammation, microcirculation and sensory nerve activity seem to play the most critical role in reducing inflammation. Therefore, researchers emphasize the study of dental nerve activity, especially in acute clinical problems in inflamed teeth and pulp regeneration. This review aims to investigate the possibility of using dental stem cells to regenerate dental nerves in order to repair dentin-pulp complexes for maintaining and restoring tooth structure and function, which nanosystems can help in this matter. Materials and Methods: In this paper, we review the literature regarding the theory of dental tissue engineering by neural differentiation of dental stem cells and nano-systems, and the comprehensive search on PubMed, Scopus, and Web of Science was conducted up to July 2022. Results: According to recent studies, dental soft and hard tissue healing also includes nerve fibers. A deeper understanding of how dental nerves are implicated in pulpitis may assist endodontic treatment. Stem cell-based treatments may be used to regenerate dental nerves to repair dentin-pulp complexes to maintain and restore tooth structure and function. Conclusion: The emphasis on dental nerve regeneration appears to be a critical stage in fostering spontaneous tooth regeneration as well as a sustainable tooth regeneration method. It is essential to further investigate dental tissue engineering by neural differentiation of dental stem cells.

Optimal culture methods for plant regeneration via shoot organogenesis in the ‘Fuji’ apple

Optimal culture methods for plant regeneration via shoot organogenesis in the ‘Fuji’ apple

Oat (Avena sativa L.) In Vitro Cultures: Prospects and Challenges for Breeding

Plant in vitro cultures have been a crucial component of efforts to enhance crops and advance plant biotechnology. Traditional plant breeding is a time-consuming process that, depending on the crop, might take up to 25 years before an improved cultivar is available to farmers. This is a problematic technique since both beneficial qualities (such as pest resistance) and negative ones (such as decreased yield) can be passed down from generation to generation. In vitro cultures provide various advantages over traditional methods, including the capacity to add desirable characteristics and speed up the development of new cultivars. When it comes to oat (Avena sativa L.), the efficient method of plant regeneration is still missing compared to the most common cereals, possibly because this cereal is known to be recalcitrant to in vitro culture. In this review, an effort has been made to provide a succinct overview of the various in vitro techniques utilized or potentially involved in the breeding of oat. The present work aims to summarize the crucial methods of A. sativa L. cultivation under tissue culture conditions with a focus on the progress that has been made in biotechnological techniques that are used in the breeding of this species.

ASSESSMENT OF THE NATURAL REGENERATION STATUS OF IRVINGIA GABONENSIS (BUSH MANGO) IN THE KWANO FOREST OF GASHAKA GUMTI NATIONAL PARK, NIGERIA

The International Union for Conservation of Nature (IUCN) describes the bush mango (Irvingia gabonensis) species as currently listed in the “lower risk or near threatened” category of its red list and an important versatile tree species in the family Irvingiaceae. I. gabonensis regenerates through seeds and it produces seeds with good germination as such; its natural size in natural habitat is actively regenerating. The present study was conducted to assess the natural regeneration status of I. gabonensis in Kwano Forest of Gashaka Gumti National Park in Nigeria. Through the biophysical survey, the number of regenerants (seedling, saplings, poles, and adults) and trees per hectare (based on diameter classes) was assessed in the forest. The study revealed that there was an increasing trend of I. gabonensis seedlings with good regeneration status. While saplings and adults are fair in regeneration per hectare in Kwano forest, respectively. Furthermore, poles had poor regeneration potentials in the study area. Hence, collectively, there was an apparent diminishing of the natural regeneration trend of I. gabonensis trees among pole classes in the Kwano Forest as a result of constant invasion and disturbances of bush pigs feedings on the ripe fruits thereby creating a setback on regeneration trend. The information is a basis to conservationists toward preservation and sustainable use of the tree species. Hence, the need for concurrent development of possible and efficient alternative method of regeneration is necessary.

The effect of regeneration temperature on the adsorptive properties of Na-ETS-4 zeotype in successive adsorption/desorption cycles

In view of the sensitivity of Na-ETS-4 zeotype to temperature, the effect of regeneration temperature on its adsorptive performance was investigated in this work. Adsorption isotherms and uptake kinetics of nitrogen and methane were measured after applying a heat treatment at temperatures of 100, 135, and 165 ◦C along with vacuum as thermal activation. Increasing the initial activation temperature in the 100–165 ◦C range led to an increase in adsorption capacity due to the intra-pore water removal. At 100 kPa, methane uptake increased from 0.2 to 0.35 mol/kg and nitrogen uptake increased from 0.07 to 0.16 mol/kg. By applying successive regenerations at 100 and 135 ◦C, the equilibrium/kinetic adsorption properties did not change. However, by successive regeneration of the adsorbent at 165 ◦C, the equilibrium capacity (for methane from 0.35 to 0.1, for nitrogen from 0.16 to 0.1 mol/kg at 100 kPa) and diffusion time constant parameter (for methane from 0.02 to 7.16 × 10−5 s−1) decreased gradually. Also, structural changes of Na-ETS-4 under successive high-temperature (i.e., 165 ◦C) regeneration were studied by XRD. A gradual reduction of Na-ETS-4 crystallinity was revealed after each regeneration at 165 ◦C. However, Na-ETS-4 showed stable adsorption performance when using only vacuum as regeneration method.

Exploring synergistic sintering factors and nanopore regeneration of calcium-based thermochemical energy storage materials

Calcium-based thermochemical energy storage is essential for high-temperature solar energy utilization. However, performance decay is inevitable in repeated calcination/carbonation cycles, even for modified materials. In this study, the effects of synergistic sintering factors on performance decay are investigated, including chemical reaction, temperature and CO2 atmosphere. More importantly, rather than complicating the initial preparation process of the anti-sintering composites to achieve higher stability, a regeneration method is proposed to repair the nanopores of sintered composites and recover their performances. After using citric acid to dissolve materials with heavily sintered morphologies and reconstruct their porous structures, the energy storage densities of both the co-doped and benchmark materials increase by 2–4 times. The regenerated Al/Mg co-doped composite also shows high cyclic stability in subsequent long-term cycles. Furthermore, DFT calculations illustrate the strong atomic interaction between CaO and dopants. The economic analysis reveals that the regeneration costs of the co-doped composites are approximately one-half of their synthesis costs, making them a cost-efficient choice for long-term industrial application. This work expands the limited perspectives of current modification research on improving cyclic stability. It can guide the actual industrial applications of thermochemical energy storage, thus enhancing material reutilization and realizing costs reduction.

Usefulness of Wedge-Shaped Implants in the Full-Arch Rehabilitation of Severe Maxillary Atrophy: A Case Report.

The management of marked horizontal bone atrophy represents a critical challenge for traditional implantology procedures. For this purpose, clinicians have developed several protocols and procedures to allow the most suitable and accurate surgical and prosthetic implant rehabilitation. Despite the development of guided bone regeneration methods and the use of small-diameter implants, the rehabilitation of thin bone areas is a clinical dilemma for the medium- and long-term survival of implant-prosthetic therapies. This clinical case evaluates the use of wedge-shaped implants for the full-arch rehabilitation of an atrophic maxilla with a thin ridge. This treatment choice allowed a minimally invasive rehabilitation, avoiding regenerative bone surgery, while respecting biologic and prosthetic limits. Furthermore, evaluation of the implant stability quotient and marginal bone loss values during the first year of follow-up allowed analysis of the behavior of this rehabilitation in fullarch maxillary cases.

A comprehensive analysis of the minimum energy and thermodynamic efficiency of regenerating aqueous electrolyte solutions in air-conditioning systems

The regeneration of aqueous electrolyte solutions is a critical and energy-intensive process in air-conditioning systems. In this work, the minimum energy required for regenerating aqueous electrolyte solutions was derived and analyzed from the perspective of the driving force. The thermodynamic efficiency of electrodialysis and thermal regeneration was evaluated and compared. The results show that the minimum energy consumption of the thermally-driven method involving water vapor removal, such as traditional packed-bed thermal regeneration, is lower than that of pressure- and electrically-driven methods that involve liquid water removal, such as electrodialysis and reverse osmosis. Utilizing dry air, such as indoor exhaust and return air, proves to be an effective approach to saving energy during thermal regeneration. For pressure- and electrically-driven regeneration methods, multi-stage processes are necessary to achieve feasibility at high concentrations. However, the complexity and cost of such systems would be considered unacceptable for air-conditioning applications. Instead, single-effect thermal processes can attain high thermodynamic efficiency at high concentrations. The analysis indicates that the thermodynamic efficiency of actual thermal processes studied ranges from 9.1 % to 40.1 %, which is significantly higher than the thermodynamic efficiency of actual electrodialysis processes (which is lower than 4.7 %).

Propagation, development phases and domestication of <i>Cyperus</i> <i>rotundus</i> L. in the Western Highlands of Cameroon

Cyperus rotundus Linn. is a potentially valuable aromatic plant given its ability to synthesise essential oil and the variety of traditional uses associated with it. The valorisation of this plant would imply the exploitation of a significant quantity of its biomass, which cannot be obtained from the wild. The aim of this study was to determine the best methods for regeneration and the development phases of C. rotundus, in order to ensure the continuous availability of its biomass. The mode of natural regeneration and the state of domestication of C. rotundus by local populations were investigated through surveys of traditional healers and herbalists. In addition, ex situ regeneration trials were carried out using vegetative propagation from bulbs and seed germination. The vegetative propagation was assessed by estimating the lag time and percentage regeneration of the bulbs, while the seed germination percentage was evaluated. The development phases of the plant were identified following the BBCH (Biologische Bundesanstalt Bundessortenamt and CHemische Industrie) scale. The yield was calculated from the underground biomass of the bulbs produced at the end of the plant life cycle. The results showed that C. rotundus regenerates naturally from bulbs and rarely from seeds. In the Western Highlands of Cameroon, traditional practitioners and herbalists have begun domesticating C. rotundus on a small scale. Propagation attempts from seed were unsuccessful in the present study. However, from bulbs, a lag time of 10 days was observed and a regeneration percentage of 88% obtained after 47 days. Five phases of development were identified including emergence (0), bolting (1), flowering (2), maturation (3) and senescence (4). The production of bulbs, which are organs containing the essential oils, was observed from the bolting phase. The biomasses of about 383, 493 and 520 kg/ha were obtained during phase 1, 2 and 3 respectively. The best propagation method and the development phases of Cyperus rotundus investigated in this work could contribute to an advance in the domestication process in order to ensure its availability and sustainability.

Direct and rapid regeneration of spent LiFePO4 cathodes via a high-temperature shock strategy

The requirement for lithium-ion batteries is rising sharply in recent years due to rapid development of electric vehicles and new energy storage. However, this increase in number of lithium-ion batteries also leads to the production of a significant number of spent batteries. Considering the potential environment pollution and waste of resources, it is absolutely imperative to recover these spent lithium-ion batteries. Conventional direct regeneration method always undergoes a slow heating rate and prolonged calcination process, which consume high energy and time. Herein, we presented an efficient, low-cost and ultrafast regeneration strategy for rapid regeneration of the spent LiFePO4 in only 20 s. Compared of traditional method, this ultrafast method consumes less energy and takes shorter time. As a result, the lithium is completely replenished and the structure of LiFePO4 is well repaired, and it demonstrates excellent initial capacity of 152 mAh g−1 at 0.1C. Furthermore, RLFP-800 exhibits a good rate performance and long-cycling stability (400 cycles at 2C without capacity recession). It is expected that this rapid regeneration strategy can be developed for practical spent LiFePO4 regeneration at low cost.

3D-Printed Composite Bioceramic Scaffolds for Bone and Cartilage Integrated Regeneration.

Osteoarthritis may result in both cartilage and subchondral bone damage. It is a significant challenge to simultaneously repair cartilage due to the distinct biological properties between cartilage and bone. Here, strontium copper tetrasilicate/β-tricalcium phosphate (Wesselsite[SrCuSi4O10]/Ca3(PO4)2, WES-TCP) composite scaffolds with different WES contents (1, 2, and 4 wt %) were fabricated via a three-dimensional (3D) printing method for the osteochondral regeneration. The physicochemical properties and biological activities of the scaffolds were systematically investigated. 2WES-TCP (WES-TCP with 2 wt % WES) composite scaffolds not only improved the compressive strength but also enhanced the proliferation of both rabbit bone mesenchymal stem cells (rBMSCs) and chondrocytes, as well as their differentiation. The in vivo study further confirmed that WES-TCP scaffolds significantly promoted the regeneration of both bone and cartilage tissue in rabbit osteochondral defects compared with pure TCP scaffolds owing to the sustained and controlled release of bioactive ions (Si, Cu, and Sr) from bioactive scaffolds. These results show that 3D-printed WES-TCP scaffolds with bilineage bioactivities take full advantage of the bifunctional properties of bioceramics to reconstruct the complex osteochondral interface, which broadens the approach to engineering therapeutic platforms for biomedical applications.

Combined Method of Intensification of Borehole Uranium Mining in Ores with Low Filtration Characteristics

The purpose of this study is to develop an effective method for increasing the filtration characteristics of ores during borehole uranium mining, depending on the geological characteristics of ores and host rocks. At the same time, it is planned to increase the productivity of production and the pick-up rate of injection wells, increase the period of uninterrupted operation of equipment and reduce operating costs for production. The geotechnological parameters of borehole uranium mining on technological blocks of various mining and geological conditions are investigated and evaluated. Core material samples were taken and the structures and compositions of the host rocks of the Santonian, Maastrichtian and Campanian ore intervals were determined by microscopic method. Based on a comparative analysis of the methods used to intensify borehole production, a combined method for restoring the permeability of the productive horizon was developed. The effective parameters of the combined well regeneration method combining fluctuations of compressed air pulses with chemical reagents – solvents are calculated and justified. The possibility of reducing the processing time of wells by a new method and increasing the productivity of wells is discussed. The method of calculation and application of the combined method of intensification of borehole production of uranium in ores with low filtration characteristics has been developed.

An Injectable Composite Hydrogel of Verteporfin-Bonded Carboxymethyl Chitosan and Oxidized Sodium Alginate Facilitates Scarless Full-Thickness Skin Regeneration.

Full-thickness skin defect has always been a major challenge in clinics due to fibrous hyperplasia in the repair process. Hydrogel composite dressings loaded with anti-fibrotic drugs have been considered as a promising strategy for scarless skin regeneration. In this work, a hydrogel composite (VP-CMCS-OSA) of carboxymethyl chitosan (CMCS) and oxidized sodium alginate (OSA), with loading anti-fibrotic drug verteporfin (VP), is developed based on two-step chemical reactions. Verteporfin is bonded with carboxymethyl chitosan through EDC/NHS treatment to form VP-CMCS, and then VP-CMCS is crosslinked with oxidized sodium alginate by Schiff base reaction to form VP-CMCS-OSA hydrogel. The characterization by SEM, FTIR, and UV-Vis shows the microstructure and chemical bonding of VP-CMCS-OSA. VP-CMCS-OSA hydrogel demonstrates the properties of high tissue adhesion, strong self-healing, and tensile ability. In the full-thickness skin defect model, the VP-CMCS-OSA composite hydrogels hasten wound healing due to the synergistic effects of hydrogels and verteporfin administration. The histological examination reveals the regular collagen arrangement and more skin appendages after VP-CMCS-OSA composite hydrogel treatment, indicating the full-thickness skin regeneration without potential scar formation. The outcomes suggest that the verteporfin-loaded composite hydrogel could be a potential method for scarless skin regeneration.

Tracing immune cells around biomaterials with spatial anchors during large-scale wound regeneration

Skin scarring devoid of dermal appendages after severe trauma has unfavorable effects on aesthetic and physiological functions. Here we present a method for large-area wound regeneration using biodegradable aligned extracellular matrix scaffolds. We show that the implantation of these scaffolds accelerates wound coverage and enhances hair follicle neogenesis. We perform multimodal analysis, in combination with single-cell RNA sequencing and spatial transcriptomics, to explore the immune responses around biomaterials, highlighting the potential role of regulatory T cells in mitigating tissue fibrous by suppressing excessive type 2 inflammation. We find that immunodeficient mice lacking mature T lymphocytes show the typical characteristic of tissue fibrous driven by type 2 macrophage inflammation, validating the potential therapeutic effect of the adaptive immune system activated by biomaterials. These findings contribute to our understanding of the coordination of immune systems in wound regeneration and facilitate the design of immunoregulatory biomaterials in the future.

Assessing regeneration strategies for sustaining intensively used Chilgoza pine-dominated community forests in Afghanistan

Income from Chilgoza pine (Pinus gerardiana) nut harvests, grazing, and the collection of firewood support forest communities within Afghanistan's Eastern Forest Complex. Persistent instability, frequent incidence of armed conflict, limited capacity of Indigenous communities, and inaccessibility to scientific expertise on forest regeneration limit options for addressing forest degradation. Representatives from forest communities in 16 districts in Khost, Paktia, and Paktika Provinces were surveyed to assess community user perceptions of Chilgoza pine regeneration status, forest protection, and acceptability of potential regeneration strategies (rotational stand harvesting, group seed tree protection, individual seed tree protection, partial cone harvesting, and integrated method). Human activity management, primarily via fine systems and forest guards, was widely reported and was regarded as important in managed forests. Respondents who reported current implementation of regeneration methods were more likely to regard natural regeneration as important and most regarding natural regeneration as very important reported the use of partial cone crop harvest as the prevailing regeneration method. Among proposed strategies, partial cone harvesting was the most frequently chosen option where regeneration was regarded as very or somewhat important. In light of the previously reported decline of forests under prevailing management practices, these results indicate a general awareness of regeneration as a forest management issue but also a significant gap among forest users in identifying the limitations of partial cone crop harvesting without additional protection for seedlings, as a potential remedy. We offer integrated rotational harvesting and grazing management strategies as a means to promote sound silviculture practices and provide a next step for community-based forest management to sustain Chilgoza pine. The context of this work in a region where tribal politics has limited outsider input allows it to serve as a model to address natural resource management issues in similar conflict-prone settings.