Europium insertion into MgAl hydrotalcite-like compound to promote the photocatalytic oxidation of nitrogen oxides.

Easy synthesis of efficient, non-toxic photocatalysts is a target to expand their potential applications. In this research, the role of Eu3+ doping in the non-toxic, affordable, and easily prepared MgAl hydrotalcite-like compounds (HTlcs) was explored in order to prepare visible light semiconductors. Eu doped MgAl-HTlcs (MA-xEu) samples were prepared using a simple coprecipitation method (water, room temperature and atmospheric pressure) and europium was successfully incorporated into MgAl HTlc frameworks at various concentrations, with x (Eu3+/M3+ percentage) ranging from 2 to 15. Due to the higher ionic radius and lower polarizability of Eu3+ cation, its presence in the metal hydroxide layer induces slight structural distortions, which eventually affect the growth of the particles. The specific surface area also increases with the Eu content. Moreover, the presence of Eu3+ 4f energy levels in the electronic structure enables the absorption of visible light in the doped MA-xEu samples and contributes to efficient electron-hole separation. The microstructural and electronic changes induced by the insertion of Eu enable the preparation of visible light MgAl-based HTlcs photocatalysts for air purification purposes. Specifically, the optimal HTlc photocatalyst showed improved NOx removal efficiency, ∼ 51% (UV-Vis) and 39% (visible light irradiation, 420 nm), with excellent selectivity (> 96 %), stability (> 7 h), and enhanced release of •O2- radicals. Such results demonstrate a simple way to design photocatalytic HTlcs suitable for air purification technologies.

Insomnia symptoms as a mediator between school connectedness and suicidal ideation in Chinese adolescents: A three-wave longitudinal model.

AIM: School connectedness is related to suicidal ideation (SI) in adolescents. However, little is known about the mediating role of insomnia symptoms in the school connectedness-SI link. This study aimed to examine the longitudinal mediating effect of insomnia symptoms on the relationship between school connectedness and SI as well as the moderating effect of sex using a three-wave longitudinal design. METHODS: A total of 3110 adolescents completed three online surveys. Data were collected over the course of 1 year, in three waves 6 months apart. Participants completed the School Connectedness Scale, Youth Self-Rating Insomnia Scale, Self-rating Idea of Suicide Scale, Beck Depression Inventory and a self-compiled demographic questionnaire. Linear regressions and mediation analyses were performed to examine the associations between school connectedness, insomnia symptoms and SI. RESULTS: School connectedness had a significant mediating effect on SI through insomnia symptoms (ßa×b = -.03, 95% confidence interval = -0.04, -0.02) after controlling for demographics and depressive symptoms. Mediation analyses showed that insomnia symptoms accounted for 23.1% of the total effects in the entire sample, with 13.3% in males and 27.3% in females. Sex had no significant moderating effect on the school connectedness-SI link association. CONCLUSIONS: The association between school connectedness and SI appears to be mediated by insomnia symptoms. Assessing and promoting school connectedness, as well as intervening and treating distress associated with insomnia, may have important clinical implications for reducing the risk of SI in adolescents.

Omics-based approaches for discovering active ingredients and regulating gut microbiota of Actinidia arguta exosome-like nanoparticles.

Exosome-like nanoparticles (ELNs) are novel naturally occurring plant ultrastructures and contain unique bioactive components. However, the potential applications and biological functions of plant ELNs, especially in the context of health promotion and disease prevention, remain largely unexplored. This study aimed to explore the biological activities and functional mechanisms of Actinidia arguta-derived exosome-like nanoparticles (AAELNs). We reported the development of AAELNs, which possess particle sizes of 157.8 nm and a negative surface charge of -23.07 mV, uptaking by RAW264.7 cells, and reduction of oxidative stress by decreasing the activity of GSH-Px and T-SOD and increasing the content of MDA. Through the use of high-throughput sequencing technology, 12 known miRNA families and 23 additional miRNAs were identified in AAELNs, GO and KEGG term enrichment analysis revealed the potential of AAELNs-miRNAs in modulating neural-relevant behaviors. Additionally, LC-MS/MS analysis detected a total of 32 major lipid classes, 430 lipid subclasses, and 1345 proteins in AAELNs. Furthermore, in vivo fluorescence disappearance and in vitro fermentation experiments demonstrated that AAELNs were able to enter the colon and improve the microbial structure. These findings suggest that AAELNs could serve as nanoshuttles in food, potentially offering health-enhancing properties.

Moderating and mediating effects of resilience between childhood trauma and psychotic-like experiences among college students.

BACKGROUND: Extensive literature revealed that childhood trauma serves as a significant risk factor for developing psychotic-like experiences (PLEs) among the general population. Resilience has been regarded as a protective factor against PLEs. However, it remains unclear what role resilience plays in the relationship between childhood trauma and PLEs. METHODS: A total of 4302 college students completed the web-based survey in January 2021. Participants completed self-report measures of sample characteristics variables, childhood trauma, and PLEs. Moderation and mediation analyses were adopted to examine the associations linking childhood trauma, resilience, and PLEs. RESULTS: PLEs were positively associated with childhood trauma while negatively associated with resilience. Resilience played a partially mediating role in the relationship between childhood trauma and PLEs. Additionally, resilience moderated the association of childhood trauma with PLEs. CONCLUSIONS: These findings indicated that resilience plays a crucial role in mediating the relationship between childhood trauma and PLEs, suggesting the potential clinical implication of enhancing resilience for the prevention and intervention of PLEs among college students.

Current Psychotic-Like Experiences Among Chinese College Students: Prevalence, Correlates, and Its Relationship with Suicidal Ideation.

Background: Current psychotic-like experiences (PLEs) are prevalent among adolescents. However, epidemiological data on the prevalence rate of current PLEs among college students and its clinical correlates are scarce and limited. To address this study gap, this study aimed to investigate the prevalence and correlates of current PLEs among Chinese college students. Methods: A cross-sectional study was designed with a sample of 18,578 college students in China. Each participant completed a survey on social-demographic characteristics variables, PLEs, sleep disturbance, depression, anxiety, and suicidal ideation. Logistic regression analyses were conducted to explore the influential factors for PLEs among all participants and suicidal ideation among those with PLEs. Results: Among Chinese college students, 40.3% of the participants reported having at least one PLE in the past month, while 7.5% had frequent PLEs. Males, age, residence location in town, left-behind experiences, poor family economic status, chronic physical illness, family history of mental disorder, BMI ≥ 28 [obesity], sleep disturbance, depression, anxiety, and suicidal ideation were independent correlates for frequent PLEs. Furthermore, the prevalence of suicidal ideation among participants with frequent PLEs was 32.1%. Lower grades, sleep disturbance, depression, and anxiety were independent predictors of suicidal ideation among college students who experience PLEs frequently. Conclusion: Current PLEs are widespread among Chinese college students. Suicidal ideation is largely prevalent among individuals who suffer frequent PLEs, suggesting that special measures and attention should be provided to these students based on relevant factors to prevent their suicidal ideation and behavior.

Optimising the acid-base ratio of Mg-Al layered double oxides to enhance CO2 capture performance: the critical role of calcination conditions.

The effect of calcination conditions (ramp rate, calcination temperature and time) on the formation of Mg2Al layered double oxides (Mg2Al LDOs) as well as their CO2 capture performance, has been systematically investigated. This study explores novel insights into the intricate relationship between these calcination conditions and the resulting surface characteristics, which play a vital role in CO2 capture efficiency. Notably, it is revealed that a rapid ramp rate (100 °C min-1) significantly increases surface area and hydroxyl concentration, leading to a 69% increase in CO2 capture efficiency compared to slower ramp rate. Conversely, short calcination times (1 h) and fast ramp rates (100 °C min-1) are observed to compromise CO2 adsorption due to the presence of dehydrated LDHs. A critical acid : base ratio of 0.37, achieved from a fast ramp rate (100 °C min-1) at 400 °C for 2 h, was found as a key threshold for optimising surface properties, effectively balancing favourable hydroxyl and less favourable strong acid sites, thereby maximizing CO2 capture performance.

Boosting the effectiveness of UV filters and sunscreen formulations using photostable, non-toxic inorganic platelets.

We have studied the size-dependent optical scattering of aqueous suspensions containing Mg2Al-LDH platelets, which exhibit high total- and side-scatterings. By incorporating 3 wt% Mg2Al-LDH platelets (280 nm) in a commercial sunscreen formulation, we achieved a twofold Sun Protection Factor boost, providing a promising, high-efficient and non-toxic strategy to enhance sunscreen effectiveness.

Quantum-improved phase estimation with a displacement-assisted SU(1,1) interferometer.

By performing two local displacement operations (LDOs) inside an SU(1,1) interferometer, called as the displacement-assisted SU(1,1) [DSU(1,1)], both the phase sensitivity based on homodyne detection and quantum Fisher information (QFI) with and without photon losses are investigated in this paper. In this DSU(1,1) interferometer, we focus our attention on the extent to which the introduced LDO affects the phase sensitivity and the QFI, even in the realistic scenario. Our analyses show that the estimation performance of DSU(1,1) interferometer is always better than that of SU(1,1) interferometer without the LDO, especially for the phase precision of the former in the ideal scenario closer to the Heisenberg limit via the increase of the LDO strength. Different from the latter, the robustness of the former can be also enhanced markedly by regulating and controlling the LDO. Our findings would open an useful view for quantum-improved phase estimation of optical interferometers.

Intrabasal Plane Defect Formation in NiFe Layered Double Hydroxides Enabling Efficient Electrochemical Water Oxidation.

Defect engineering has proven to be one of the most effective approaches for the design of high-performance electrocatalysts. Current methods to create defects typically follow a top-down strategy, cutting down the pristine materials into fragmented pieces with surface defects yet also heavily destroying the framework of materials that imposes restrictions on the further improvements in catalytic activity. Herein, we describe a bottom-up strategy to prepare free-standing NiFe layered double hydroxide (LDH) nanoplatelets with abundant internal defects by controlling their growth behavior in acidic conditions. Our best-performing nanoplatelets exhibited the lowest overpotential of 241 mV and the lowest Tafel slope of 43 mV/dec for the oxygen evolution reaction (OER) process, superior to the pristine LDHs and other reference cation-defective LDHs obtained by traditional etching methods. Using both material characterization and density functional theory (DFT) simulation has enabled us to develop relationships between the structure and electrochemical properties of these catalysts, suggesting that the enhanced electrocatalytic activity of nanoplatelets mainly results from their defect-abundant structure and stable layered framework with enhanced exposure of the (001) surface.

Internet addiction and suicidal ideation among Chinese college students: the mediating role of psychotic-like experiences.

Background: Individuals with Internet addiction (IA) are at significant risk of suicide-related behaviors. This study aimed to investigate the relationships among IA, psychotic-like experiences (PLEs), and suicidal ideation (SI) among college students. Methods: A total of 5,366 college students (34.4% male, mean age 20.02 years) were assessed using the self-compiled sociodemographic questionnaires, Revised Chinese Internet Addiction Scale (CIAS-R), 15-item Positive subscale of the Community Assessment of Psychic Experiences (CAPE-P15), Self-rating Idea of Suicide Scale (SIOSS), and 2-item Patient Health Questionnaire (PHQ-2). Results: The prevalence of IA and SI were 9.3 and 12.1% among Chinese college students, respectively. There were direct effects of IA and PLEs on SI. The total effect of IA on SI was 0.18 (p < 0.001). PLEs mediated the relationship between IA and SI (Indirect effect = 0.07). Conclusion: IA had both direct and indirect effects on SI. These findings enable us to elucidate the mechanism of how IA influences individual SI, which can provide vital information for developing and implementing targeted interventions and strategies to alleviate SI among Chinese college students.

Core-shell silica@CuxZnAl LDH catalysts for efficient CO2 hydrogenation to methanol.

The efficient production of methanol by reduction of CO2 using green hydrogen is a promising strategy from both a green chemistry and a carbon net zero perspective. Herein, we report the synthesis of well-dispersed core-shell catalyst precursors using silica@CuxZnAl-LDHs that can convert CO2 to methanol. The catalyst precursors can be formed using either a commercially available silica (ES757) or a mesoporous silica (e.g. MCM-48). These hybrid materials show significantly enhanced catalytic performance compared to the equivalent unsupported CuxZnAl LDH precursor. Space-time yields of up to 0.7 gMeOH gcat-1 h-1 under mild operating conditions were observed.

The MAGIC algorithm probability (MAP)-guided preemptive therapy of acute graft versus host disease with methylprednisolone: A randomized controlled trial.

Acute graft versus host disease (aGvHD) is a severe complication that arises in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) and remains the primary cause of nonrelapse mortality (NRM). The MAGIC algorithm probability (MAP) has been proposed to identify patients at intermediate and high risk of developing aGvHD. The levels of suppression of tumorigenicity 2 (ST2) and regenerating islet-derived 3α (Reg3α) were assessed, and MAP was calculated on days 7, 14, 21, and 28 after allo-HSCT. Based on the MAP results, patients were classified into low-, intermediate-, or high-risk groups for the development of aGvHD. Random assignment was performed to allocate intermediate- or high-risk patients to receive preemptive therapy with methylprednisolone or not. The 100-day cumulative incidences of grade 2 or higher (35.5% ± 8.6%) and grade 3 or higher (12.9% ± 6.0%) aGvHD in the methylprednisolone group were significantly lower than those in the control group (66.7% ± 7.9%, p = .01; 42.9% ± 8.4%, p = .01), and similar to those observed in the low-risk group (31.7% ± 7.3%, p = .75; 2.4% ± 2.4%, p = .08). The 6-month cumulative incidences of NRM were 14.1% ± 6.6%, 22.7% ± 7.1%, and 2.4% ± 2.4% in the methylprednisolone, control, and low-risk groups, respectively, with no significant difference between the methylprednisolone and control groups (p = .29). Methylprednisolone did not increase infections (p = .34). The 100-day cumulative incidences of cytomegalovirus (CMV) reactivation were 67.7% ± 8.4%, 65.6% ± 8.4%, and 46.3% ± 7.8% (p = .08), and those of grade 2 or higher hemorrhagic cystitis were 29.0% ± 8.2%, 45.2% ± 8.9% and 22.0% ± 6.5% (p = .11) in the methylprednisolone, control, and low-risk groups, respectively. MAP-guided preemptive therapy for aGvHD is promising. The long-term efficacy and safety remain to be investigated.

A latent profile analysis of sleep disturbance in relation to mental health among college students in China.

Aims: This study aimed to examine the subtype classification characteristics of sleep disturbance (SD) in college students and their associations with sample characteristic factors and mental health outcomes. Methods: The sample comprised 4,302 college students (Mean age = 19.92 ± 1.42 years, 58.6% females). The Youth Self-Rating Insomnia Scale, Beck Depression Inventory, 8-item Positive Subscale of the Community Assessment of Psychic Experiences, and 10-item Connor-Davidson Resilience Scale were used to assess adolescents' sleep disturbance, depressive symptoms, psychotic-like experiences (PLEs), and resilience. Latent profile analysis, logistic regression, and liner regression analysis were used to analyze the data. Results: Three subtypes of SD in college students were identified: the high SD profile (10.6%), the mild SD profile (37.5%), and the no SD profile (51.9%). Compared with college students in the "no SD" profile, risk factors for "high SD" include being male and poor parental marital status. Sophomores were found to predict the "high SD" profile or "mild SD" profile relative to the "no SD" profile. College students in the "mild SD" profile or "high SD" profile were more likely to have a higher level of depressive symptoms and PLEs, while a lower level of resilience. Conclusion: The findings highlighted that target intervention is urgently needed for male college students, sophomores, and those with poor parental marital status in the "mild SD" profile or "high SD" profile.

A novel conditioning regimen of chidamide, cladribine, gemcitabine, and busulfan in the autologous stem cell transplantation of aggressive T-cell lymphoma.

Background: The prognosis of patients with peripheral T-cell (PTCL) or lymphoblastic T-cell lymphoma (T-LBL) remains poor under current conditioning regimens before receiving autologous stem cell transplantation (ASCT). Methods: Patients with PTCL or T-LBL were enrolled to receive ASCT using the conditioning regimen of chidamide, cladribine, gemcitabine, and busulfan (ChiCGB). Positron emission tomography-computed tomography (PET/CT) was used to evaluate the response to ASCT. Overall survival (OS) and progression-free survival (PFS) were employed to assess the patient outcome, and adverse events were used to assess the regimen's safety. The survival curve was estimated via the Kaplan-Meier method. Results: Twenty-five PTCL and 11 T-LBL patients were recruited. The median time to neutrophile and platelet engraftments was 10 days (8-13 days) and 13 days (9-31 days), respectively. The 3-year PFS and OS were 81.3 ± 7.2% and 88.5 ± 5.4% for all patients; 92.0 ± 5.4% and 81.2 ± 8.8% for PTCL patients; and both 81.8 ± 11.6% for T-LBL patients, respectively. The 3-year PFS and OS were both 92.9 ± 4.9% for patients with complete response (CR) but 50.0 ± 17.7% and 75.0 ± 15.3% for patients with non-CR, respectively. Infection was the most common non-hematological toxicity, and all toxicities were mild and controllable. Conclusions: ChiCGB was a potentially effective and well-tolerated conditioning regimen to improve the prognosis of patients with aggressive T-cell lymphoma. Future randomized controlled trials are needed to assess ChiCGB as a conditioning regimen for ASCT.

Psychotic-like experiences during COVID-19 lockdown among adolescents: Prevalence, risk and protective factors.

OBJECTIVE: Although plenty of evidence has shown the huge negative impact of COVID-19 on individuals' mental health conditions, little is known about its impact on the psychotic-like experiences (PLEs) in the general population. We aim to explore the prevalence of PLEs and relevant influential factors among adolescents during COVID-19 lockdown. METHODS: A total of 3234 students completed one online survey between April to May 2020. PLEs were assessed using the 15-item Positive Subscale of the Community Assessment of Psychic Experiences (CAPE-P15). Resilience, social support, childhood trauma, and a series of socio-demographic factors were also evaluated. RESULTS: In this sample, 51.4 % adolescents reported having at least one PLE, while 11.6 % experienced PLEs frequently during COVID-19 lockdown. Senior high school students showed more frequent PLEs than college students (p < 0.001). Female gender (OR = 1.77), history of mental disorders (OR = 3.07) or chronic physical illness (OR = 2.04), having relatives or friends being infected with COVID-19 (OR = 3.12), longer daily exposure to media coverage of the COVID-19 (OR = 1.60), and more childhood trauma (OR = 1.54-3.49) were correlated with more frequent PLEs, while higher resilience (OR = 0.35-0.54) and more perceived social support (OR = 0.63-0.72) were associated with decreased odds for frequent PLEs. Additionally, there were several differences among the influential factors between senior high school and college students. CONCLUSIONS: PLEs were relatively common among Chinese adolescents, with higher prevalence among senior high school students during COVID-19 lockdown. Adolescents with specific characteristics should receive more attention in the development of intervention measures in mental health during pandemic lockdown.

Recent advances in direct air capture by adsorption.

Significant progress has been made in direct air capture (DAC) in recent years. Evidence suggests that the large-scale deployment of DAC by adsorption would be technically feasible for gigatons of CO2 capture annually. However, great efforts in adsorption-based DAC technologies are still required. This review provides an exhaustive description of materials development, adsorbent shaping, in situ characterization, adsorption mechanism simulation, process design, system integration, and techno-economic analysis of adsorption-based DAC over the past five years; and in terms of adsorbent development, affordable DAC adsorbents such as amine-containing porous materials with large CO2 adsorption capacities, fast kinetics, high selectivity, and long-term stability under ultra-low CO2 concentration and humid conditions. It is also critically important to develop efficient DAC adsorptive processes. Research and development in structured adsorbents that operate at low-temperature with excellent CO2 adsorption capacities and kinetics, novel gas-solid contactors with low heat and mass transfer resistances, and energy-efficient regeneration methods using heat, vacuum, and steam purge is needed to commercialize adsorption-based DAC. The synergy between DAC and carbon capture technologies for point sources can help in mitigating climate change effects in the long-term. Further investigations into DAC applications in the aviation, agriculture, energy, and chemical industries are required as well. This work benefits researchers concerned about global energy and environmental issues, and delivers perspective views for further deployment of negative-emission technologies.

Aged layered double hydroxide nanosheet-polyvinyl alcohol dispersions for enhanced gas barrier coating performance.

Whilst applying a coating layer to a polymer film is a routine approach to enhance the gas barrier properties of the film, it is counter-intuitive to consider that the gas barrier performance of the film would improve by ageing the coating dispersion for weeks before application. Herein, we report that the oxygen barrier performance of a 12 µm PET film coated with a dispersion of inorganic nanosheets in polyvinyl alcohol can be significantly enhanced by ageing this coating dispersion for up to 8 weeks before application. We found up to a 37-fold decrease in the oxygen transmission rate (OTR) of the PET coated film using aged dispersions of [Mg0.66Al0.33(OH)2](NO3)0.33 layered double hydroxide nanosheets (Mg2Al-LDH NS) in polyvinyl alcohol (PVA) compared to the film coated with an equivalent freshly prepared LDH/PVA dispersion. A limiting OTR value of 0.31 cc m-2 day-1 was achieved using the PET film coated with a 3 week aged LDH NS/PVA dispersion. X-ray diffraction experiments show that the degree of in plane alignment of LDH NS on the PET film surface increased significantly from 70.6 ± 0.6 to 86.7 ± 0.6 (%) (100% represents complete alignment of LDH NS platelets on the film surface) for the 4 week aged dispersion compared to the freshly prepared layer. We postulate that when the Mg2Al-LDH NS are aged in PVA the coiled PVA aggregates start to unwrap and attach onto the Mg2Al-LDH NS through hydrogen bonding and eventually form a hydrogen bonded ordered network that facilitates the alignment of nanosheet dispersions during the coating process. Our results suggest that the ageing of inorganic nanosheet dispersions in PVA or other potential hydrogen bonding adhesive systems could be a general approach to improve the alignment of the nanosheets on the polymer film surface once applied and thus improve their performance characteristics for barrier coating applications.

The effect of lipid metabolism regulator anthocyanins from Aronia melanocarpa on 3T3-L1 preadipocytes and C57BL/6 mice via activating AMPK signaling and gut microbiota.

This study investigated lipid metabolism regulation by anthocyanins from Aronia melanocarpa (AAM) in 3T3-L1 preadipocytes and high fat diet (HFD) mice. Ultra-performance liquid chromatography/ion mobility quadrupole time-of-flight mass spectrometry analysis identified the constituents of AAM, which decreased lipid content and inflammation in 3T3-L1 cells without cytotoxicity. Meanwhile, taking normal diet and orlistat mice as references, AAM supplementation improved blood lipid levels and adipocyte degeneration, promoted beneficial gut microbial growth, and maintained lipid metabolism in HFD mice. Furthermore, AAM activated the AMP-activated protein kinase (AMPK) signaling pathway, accompanied by the regulation of adipogenic transcription factors and their target genes in vitro and in vivo. Collectively, our data demonstrated that AAM exhibits anti-adipogenic activities that were partially mediated by the AMPK pathway and gut microbiota regulation. This study provides new insight into the regulation of lipid metabolism by AAM and suggests that AAM has potential therapeutic effects on hyperlipidemia.

Ni2Mn-layered double oxide electrodes in organic electrolyte based supercapacitors.

The development of future mobility (e.g. electric vehicles) requires supercapacitors with high voltage and high energy density. Conventional active carbon-based supercapacitors have almost reached their limit of energy density which is still far below the desired performance. Advanced materials, particularly metal hydroxides/oxides with tailored structure are promising supercapacitor electrodes to push the limit of energy density. To date, research has largely focused on evaluation of these materials in aqueous electrolyte, while this may enable high specific capacitance, it results in low working voltage window and poor cycle stability. Herein, we report the development of Ni2Mn-layered double oxides (Ni2Mn-LDOs) as mixed metal oxide-based supercapacitor electrodes for use in an organic electrolyte. Ni2Mn-LDO obtained by calcination of [Ni0.66Mn0.33(OH)2](CO3)0.175·nH2O at 400 °C produced the best performing Ni2Mn-LDOs with high working voltage of 2.5 V and a specific capacitance of 44 F g-1 (at 1 A g-1). We believe the performance of the Ni2Mn-LDOs is related to its unique porous structure, high surface area and the homogeneous mixed metal oxide network. Ni2Mn-LDO outperforms both the single metal oxides (NiO, MnO2) and the equivalent physical mixture of the two oxides. We propose this performance boost arises from synergy between NiO and MnO x due to a more effective homogeneous network of NiO/MnO x domains in the Ni2Mn-LDO. This work clearly shows the advantage of an LDO over the single component metal oxides as well as the physical mixture of mixed metal oxides and highlights the possibilities of development of further mixed metal oxides-based supercapacitors in organic electrolyte using LDH precursors.