Perovskite Single Crystals by Vacuum Evaporation Crystallization.

Perovskite single crystals have attracted tremendous attention owing to their excellent optoelectronic properties and stability compared to typical multicrystal structures. However, the growth of high-quality perovskite single crystals (PSCs) generally relies on temperature gradients or the introduction of additives to promote crystal growth. In this study, a vacuum evaporation crystallization technique is developed that allows PSCs to be grown under extremely stable conditions at constant temperature and without requiring additives to promote crystal growth. The new method enables the growth of PSCs of unprecedented quality, that is, MAPbBr3 single crystals that exhibit an ultranarrow full width at half maximum of 0.00701°, which surpasses that of all previously reported values. In addition, the MAPbBr3 single crystals deliver exceptional optoelectronic performance, including a long carrier lifetime of 1006 ns, an ultralow trap-state density of 3.67 × 109 cm-3, and an ultrahigh carrier mobility of 185.86 cm2 V-1 s-1. This method is applicable to various types of PSCs, including organic-inorganic hybrids, fully inorganic structures, and low-dimensional structures.

Interface-Tension-Assisted Temperature-Gradient Crystallization of High-Quality MAPbBr3 Perovskite Single Crystals with Low Defect Densities.

Comprehensive understanding and precise manipulation of the crystallization process for organic-inorganic hybrid perovskite materials are crucial for advancing perovskite single-crystal optoelectronic technology. In this study, we theoretically and experimentally investigated the influence of interface tension on the synthesis of perovskite single crystals. On the basis of the understanding of the nucleation and growth mechanisms, we developed a polydimethylsiloxane-assisted temperature-gradient growth technique to prepare high-quality MAPbBr3 single crystals. Using this technique, we harvested some high-quality MAPbBr3 single crystals, with the narrowest reported full width at half-maximum (0.00806°) of X-ray diffraction rocking curve, the longest carrier lifetime of 1002 ns, and an ultralow trap-state density of 4.25 × 109 cm-3. Furthermore, the X-ray detector fabricated using our MAPbBr3 single crystal exhibited a high sensitivity of 7275 µC Gy1- cm2 and a low minimum detection limit of 0.67 µGy s-1. This paper presents a novel method to control the crystallization and growth processes of high-quality perovskite single crystals.

Mono- and Co-Doped Mn-Doped CsPbCl3 Perovskites with Enhanced Doping Efficiency and Photoluminescent Performance.

To investigate the effect of Mn and other metal dopants on the photoelectronic performance of CsPbCl3 perovskites, we conducted a series of theoretical analyses. Our findings showed that after Mn mono-doping, the CsPbCl3 lattice contracted and the bonding strength increased, resulting in a more compact structure of the metal octahedral cage. The relaxation of the metal octahedral cage, along with the Jahn-Teller effect, results in a decrease in lattice strain between the octahedra and a reduction in the energy of the entire lattice due to the deformation of the metal octahedron. These three factors work together to reduce intrinsic defects and enhance the stability and electronic properties of CsPbCl3 perovskites. The solubility of the Mn dopant is significantly increased when co-doped with Ni, Fe, and Co dopants, as it compensates for the lattice strain induced by Mn. Doping CsPbCl3 perovskites reduces the band gap due to the decreased contributions of 3d orbitals from the dopants. Our analyses have revealed that strengthening the CsPbCl3 lattice and reducing intrinsic defects can result in improved stability and PL properties. Moreover, increasing Mn solubility and decreasing the bandgap can enhance the PLQY of orange luminescence in CsPbCl3 perovskites. These findings offer valuable insights for the development of effective strategies to enhance the photoelectronic properties of these materials.

Solid-gas carbonate formation during dust events on Mars.

Electrostatic discharge experiments under simulated martian atmospheric conditions indicate that atmospheric CO2 has been sequestered into carbonate by the Mars dust activities during the Amazonia era.

A potential application for life-related organics detection on Mars by diffuse reflectance infrared spectroscopy.

Life information searching is a hot point for Mars exploration. Ancient Mars was very likely to reach a habitable environment, and there was a real possibility of arising life on Mars. However, the current Mars has a harsh environment. Under such conditions, life materials on Mars are supposed to have taken the form of relatively primitive microbial or organic residues, which might be preserved in some mineral matrices. Detection of these remnants is of great significance for understanding the origin and evolution of life on Mars. The best detection method is in-situ detection or sample return. Herein, diffuse reflectance infrared spectroscopy (DRIFTS) was used to detect characteristic spectra and the limit of detection (LOD) of potential representative organic compounds with associated minerals. In view of high oxidation due to the electrostatic discharge (ESD) during dust actives on Martian surface. The degradation of organic matter by ESD process was studied under simulated Mars conditions. Our results show that the spectral characteristics of organic matter are significantly different from that of associated minerals. The different organic samples have different mass loss and color change after ESD reaction. And the signal intensity of infrared diffuse reflection spectrum can also reflect the changes of organic molecules after ESD reaction. Our results indicated that the degradation products of organics rather than organic itself are most likely to be founded on current Martian surface.

A Mars Environment Chamber Coupled with Multiple In Situ Spectral Sensors for Mars Exploration.

Laboratory simulation is the only feasible way to achieve Martian environmental conditions on Earth, establishing a key link between the laboratory and Mars exploration. The mineral phases of some Martian surface materials (especially hydrated minerals), as well as their spectral features, are closely related to environmental conditions. Therefore, Martian environment simulation is necessary for Martian mineral detection and analysis. A Mars environment chamber (MEC) coupled with multiple in situ spectral sensors (VIS (visible)-NIR (near-infrared) reflectance spectroscopy, Raman spectroscopy, laser-induced breakdown spectroscopy (LIBS), and UV-VIS emission spectroscopy) was developed at Shandong University at Weihai, China. This MEC is a comprehensive research platform for Martian environmental parameter simulation, regulation, and spectral data collection. Here, the structure, function and performance of the MEC and the coupled spectral sensors were systematically investigated. The spectral characteristics of some geological samples were recorded and the effect of environmental parameter variations (such as gas pressure and temperature) on the spectral features were also acquired by using the in situ spectral sensors under various simulated Martian conditions. CO2 glow discharge plasma was generated and its emission spectra were assigned. The MEC and its tested functional units worked well with good accuracy and repeatability. China is implementing its first Mars mission (Tianwen-1), which was launched on 23 July 2020 and successfully entered into a Mars orbit on 10 February 2021. Many preparatory works such as spectral databases and prediction model building are currently underway using MECs, which will help us build a solid foundation for real Martian spectral data analysis and interpretation.

Portable Dielectric Barrier Discharge-Atomic Emission Spectrometer.

This paper describes the first demonstration of a portable dielectric barrier discharge-atomic emission spectrometer (DBD-AES). The instrument primarily consists of a miniature electro-thermal vaporizer (ETV), DBD, and optical signal acquisition units. It weighs only 4.5 kg and is powered by a 24 V DC battery with a maximum power consumption of 37 W. The accompanying software can be operated on a laptop computer. A specially designed quartz tube integrates the ETV unit with the DBD chamber. The effects of experimental parameters were investigated. The limit of detection (LOD) for mercury was 0.4 µg L-1 (1.2 pg) with a sampling volume of 3 µL. The instrument is applicable for multielement analysis, and the LODs ranged from 0.16 to 11.65 µg L-1 for Zn, Pb, Ag, Cd, Au, Cu, Mn, Fe, Cr, and As. The instrument was also validated by in-field analysis of seawater samples. The experimental results demonstrated the sensitivity, reliability, and practicality of the instrument.

Cold excitation and determination of hydrogen sulfide by dielectric barrier discharge molecular emission spectrometry.

A low-temperature microplasma generated in a dielectric barrier discharge (DBD) was used as a radiation source for the excitation of hydrogen sulfide and its determination by molecular emission spectrometry (MES). The excitation/emission chamber was enclosed to eliminate spectral interference from ambient air. The spectral emission lines of hydrogen sulfide were clearly discriminated from the background spectrum, and the emission line at 365.06 nm was selected for parameter optimization and quantitative analysis. The S(2-) ions in aqueous samples were reacted with acid to generate hydrogen sulfide and then determined. The experimental parameters affecting the determination of hydrogen sulfide and S(2-) were optimized. The limits of detection were 1.4 mg m(-3) for H2S and 11.2 mg L(-1) for S(2-). The repeatability of the method was satisfactory, as the RSD values were 2.3% for H2S and 1.8% for S(2-). The enclosed DBD-MES system was demonstrated to be a useful tool for the determination of hydrogen sulfide in gas samples and S(2-) in aqueous samples.

Activation of adenosine receptor potentiates the anticonvulsant effect of phenytoin against amygdala kindled seizures.

Drug resistance in epilepsy is considered as a complicated and multifactorial problem. Poor penetration of antiepileptic drugs (AEDs) across blood-brain barrier (BBB) into the brain, which results in insufficient level of the drugs at the targeted brain region, has been discussed as one mechanism contributing to pharmacoresistance of epilepsies. Therefore, modulating permeability of BBB is the effective treatment strategy since it facilitates the entry of AEDs into the central nervous system (CNS). Recently, signaling through receptors for the adenosine has been identified as a potent modulator of BBB permeability. This paper aimed to investigate the effects of auxiliary application of adenosine receptor (AR) agonist on amygdala-kindled seizures in adult male Wistar rats. When fully kindled seizures were achieved by daily electrical stimulation of the amygdala, rats were randomly divided into three groups: control, phenytoin, and phenytoin (PHT)+5'-N-ethylcarboxamidoadenosine (NECA) groups. NECA (0.08 mg/kg, i.v.) was applied to the PHT+NECA group after the administration of PHT (75 mg/kg, i.p. on the first day; 50mg/kg, i.p. on the following 9 days). Intravenous infusion of NECA resulted in a significant increase in brain PHT levels as compared with the PHT treatment alone. On the other hand, the auxiliary application of NECA dramatically decreased the frequency of generalized seizures and seizure stage, shortened duration of afterdischarge and generalized seizures, as well as the elevated the afterdischarge threshold and generalized seizures threshold. Our study demonstrated that auxiliary application of AR agonist enhanced brain antiepileptic drug levels and strengthened the anticonvulsant properties of PHT against amygdala kindled seizures.

Targeting the mTOR signaling network for Alzheimer's disease therapy.

The mammalian target of rapamycin (mTOR) is a highly conserved serine/threonine kinase that can sense environmental stimuli such as growth factors, energy state, and nutrients. It is essential for cell growth, proliferation, and metabolism, but dysregulation of mTOR signaling pathway is also associated with a number of human diseases. Encouraging data from experiments have provided sufficient evidence for the relationship between the mTOR signaling pathway and Alzheimer's disease (AD). Upregulation of mTOR signaling pathway is thought to play an important role in major pathological processes of AD. The mTOR inhibitors such as rapamycin have been proven to ameliorate the AD-like pathology and cognitive deficits effectively in a broad range of animal models. Application of mTOR inhibitors indicates the potential value of reducing mTOR activity as an innovative therapeutic strategy for AD. In this review, we will focus on the recent process in understanding mTOR signaling pathway and the vital involvement of this signaling pathway in the pathology of AD, and discuss the application of mTOR inhibitors as potential therapeutic agents for the treatment of AD.

Association of GWAS-linked loci with late-onset Alzheimer's disease in a northern Han Chinese population.

OBJECTIVE: Five genomewide association studies (GWAS) in white populations have recently identified and confirmed 9 novel Alzheimer's disease (AD) susceptibility loci (CLU, CR1, PICALM, BIN1, ABCA7, MS4A gene cluster, CD2AP, CD33, and EPHA1). These studies have been conducted almost exclusively in white populations and it is unclear whether these observations generalize to populations with different ethnicities. METHODS: We recruited 1224 unrelated northern Han Chinese subjects comprising 612 patients with a clinical diagnosis of late-onset AD (LOAD) according to the criteria of the National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association and 612 healthy age- and sex-matched control subjects. Because of our previous study investigating CLU, CR1, and PICALM in the Han population, we limited the current analysis to BIN1, ABCA7, MS4A gene cluster, CD2AP, CD33, and EPHA1. RESULTS: In a multivariate analysis, associations of MS4A6A (rs610932; odds ratio = 0.632, Bonferroni corrected P = .019) and CD33 (rs3865444; odds ratio = 1.492, Bonferroni corrected P = .017) with LOAD were replicated successfully. When these data were stratified by apolipoprotein E (APOE) ε4 status, both rs610932 and rs610932 were evident only among subjects without the APOE ε4 allele. For BIN1, assuming a dominant model of inheritance, a positive association for rs7561528 in APOE ε4 carriers was observed. This association, however, did not remain significant after Bonferroni correction. As for ABCA7, CD2AP, and EPHA1 single nucleotide polymorphisms from recent GWAS, despite the similar directional effects, no significant differences in genotype and estimated allele frequency distribution between patients and control subjects were observed. CONCLUSIONS: This study provides the first independent evidence that MS4A and CD33 loci are associated with the risk of LOAD in northern Han Chinese population. Genotypes at the two loci confer risk predominantly in APOE ε4-negative subjects.

Clusterin in Alzheimer's disease.

Clusterin, also known as apolipoprotein J, is a ubiquitous multifunctional glycoprotein. Following its identification in 1983, clusterin was found to be clearly increased in Alzheimer's disease (AD). Later research demonstrated that clusterin could bind amyloid-beta (Abeta) peptides and prevent fibril formation, a hallmark of AD pathology. In addition to preventing excessive inflammation, intracellular clusterin was found to reduce apoptosis and oxidative stress. Although early studies were inconclusive, two recent large-scale genome-wide association studies (GWAS) independently identified variants within the clusterin gene as risk factors for developing AD. This review focuses on the characteristics of clusterin and possible mechanisms of its relationship to AD.

Genetic association of SLC2A14 polymorphism with Alzheimer's disease in a Han Chinese population.

Glucose uptake and metabolism are impaired in Alzheimer's disease (AD) brain, which appear to be a cause, rather than a consequence of neurodegeneration. Recently, the gene of the 14th isoform of subfamily A of solute carrier family 2 (SLC2A14), encoding glucose transporter 14 (GLUT14), was identified for the association in vivo with AD pathology of Tau, and rs10845990 within SLC2A14 showed association with AD in Caucasians. In order to evaluate the involvement of the SLC2A14 polymorphism in the risk of developing late-onset Alzheimer's disease (LOAD) in Chinese, we performed an independent case-control association study in a Han Chinese population (597 LOAD cases and 605 healthy controls). There were significant differences in genotype and allele frequencies between LOAD cases and controls (genotype P = 0.015, allele P = 0.039). The G-carrying genotype (GT + GG) individuals showed a 1.41-fold increased risk compared with the TT genotype carriers (odds ratio (OR) = 1.41, 95 % confidence interval (CI) = 1.11-1.79, P = 0.005, Power = 83.6 %). After stratification by ApoE ε4-carrying status, rs10845990 polymorphism was only significantly associated with LOAD in non-ApoE ε4 allele carriers (P < 0.001). Multivariate logistic regression analysis also conferred this positive association between the SNP rs10845990 and LOAD in the dominant and additive model after adjustment for age, gender, and the ApoE ε4 carrier status. These results suggested that SLC2A14 polymorphism has a possible role in changing the genetic susceptibility to LOAD in a Han Chinese population.

Lack of association between rs597668 polymorphism near EXOC3L2 and late-onset Alzheimer's disease in Han Chinese.

Recently, an international genome-wide association study (GWAS) additionally found rs597668 near EXOC3L2/BLOC1S3/MARK4 was a new genome-wide significance locus associated with late-onset Alzheimer's disease (LOAD) in Caucasians. Follow-up replication studies were conducted almost exclusively in Caucasians, and the effects of the risk locus in other populations are as yet unknown. This study investigated the GWAS-associated locus near EXOC3L2 in 1205 unrelated Northern Han Chinese subjects comprising 598 LOAD patients and 607 healthy controls matched for gender and age. The results showed no significant differences in the genotypic or allelic distributions of rs597668 polymorphism between LOAD cases and healthy controls (genotype: P=0.653; allele: P=0.603), even after stratification for apolipoprotein E (APOE) ɛ4 status and statistical adjustment for age, gender and APOE ɛ4 status. This study suggests that the rs597668 polymorphism near EXOC3L2 may not play a major role in the susceptibility to LOAD in the Northern Han Chinese population.

Replication of the MTHFD1L gene association with late-onset Alzheimer's disease in a Northern Han Chinese population.

We conducted a replication study of the 2 genetic variants, rs11754661 and rs2073067, in MTHFD1L that have been recently reported to be associated with late-onset Alzheimer's disease (LOAD) in a genome-wide study in Caucasians. The associations were evaluated in a case-control sample comprising 1,189 Northern Han-Chinese individuals. The rs11754661 polymorphism is associated with LOAD (OR = 1.727; p = 0.016). For rs2073067, LOAD association was found only in APOEε4 carriers (OR = 0.400; p < 0.001). Haplotype analysis revealed the "AC" haplotype increased the risk of developing LOAD (OR = 1.730; p = 0.015). Our findings support a role of MTHFD1L gene in LOAD.

Blood clusterin levels, rs9331888 polymorphism, and the risk of Alzheimer's disease.

Variants in the clusterin gene have been associated with Alzheimer's disease (AD) through replicated genome-wide studies, but the underlying mechanisms remain unknown. In this study the association of the AD clusterin common risk polymorphism rs9331888 with blood clusterin levels was tested in 104 AD subjects and 104 healthy controls. Blood clusterin levels were significantly elevated in AD patients (p < 0.05). The rs9331888 AD-risk variant was associated with low clusterin mRNA and protein levels in an allele-dose dependent manner in both groups (p < 0.001). This study indicates that the rs9331888 AD-risk variant is associated with low blood clusterin levels.

Common variants in toll-like receptor 4 confer susceptibility to Alzheimer's disease in a Han Chinese population.

Toll-like receptor 4 (TLR4) represents a reasonable functional and positional candidate gene for Alzheimer's disease (AD) as it is located within the previous identified linkage region of AD on chromosome 9q, and functionally is involved in the microglia-mediated inflammatory response, amyloid-ß (Aß) plaque formation and Aß clearance. To test whether variants in the TLR4 gene are associated with late-onset AD (LOAD), we organized a multicenter study of 785 subjects (399 cases and 386 matched controls) in a Han Chinese population. Ten single nucleotide polymorphisms (SNPs) that span the TLR4 gene, from approximately 5 kb of the predicted 5'-untranslated region (UTR) to approximately 6 kb of the predicted 3'- UTR, were selected and their associations with LOAD risk factors were assessed. With respect to allelic diversity, the minor alleles of seven SNPs (rs10759930, rs1927914, rs1927911, rs12377632, rs2149356, rs7037117, and rs7045953) in TLR4 showed consistent protective effects against the risk of developing LOAD. With regard to genotypic diversity, individuals carrying at least one minor allele of each SNP above had a consistently lower risk of LOAD than those with no copies of the minor alleles (ORs ranging from 0.445 to 0.637). rs7045953, located in the 3'-UTR of TLR4, was most strongly associated with LOAD, and when incorporated into a haplotype with rs10759930, the strongest association was detected (P = 1.7x10-6, Pc s1.0x10-4). Our data suggests that the TLR4 gene contributes to the susceptibility for LOAD in Han Chinese.

Anticonvulsant effect of unilateral anterior thalamic high frequency electrical stimulation on amygdala-kindled seizures in rat.

Deep brain stimulation (DBS) is an emerging treatment of epilepsy. Anterior nucleus of the thalamus (ANT) is considered to be an attractive target due to its close connection to the limbic structures and wide regions of neocortex. In this study, we examined the effect of unilateral high frequency stimulation (HFS) of the ANT on amygdala-kindled seizures in Wistar rats. When fully-kindled seizures were achieved by daily amygdala kindling, HFS (15 min train of 100 µs pulses at 200 Hz and 450-800 µA) was delivered to the ipsilateral or contralateral ANT immediately before the kindling stimulation for 15 days. HFS of the ipsilateral ANT significantly decreased the incidence of generalized seizures and the mean behavioral seizure stage and afterdischarge duration (ADD), and shortened cumulative ADD and cumulative generalized seizure duration. Furthermore, HFS of the ipsilateral ANT significantly increased the afterdischarge threshold (ADT). Our data suggest that unilateral HFS of the ANT may be an effective method of inhibiting kindled seizures by suppressing the susceptibility to seizures and generating long lasting anti-epileptic effect preventing the recurrence of kindled seizures, providing an alternative to bilateral ANT DBS for refractory epilepsy.

Implication of IL-33 gene polymorphism in Chinese patients with Alzheimer's disease.

Interleukin-33 (IL-33), a newly described member of the IL-1 family, is located on chromosome 9p24, a chromosomal region of interest in Alzheimer's disease (AD) defined by many genome-wide studies. Three intronic rs1157505, rs11792633, and rs7044343 single nucleotide polymorphisms (SNPs) within IL-33 have recently been reported to be associated with risk of AD in Caucasian populations. In order to assess the involvement of the IL-33 polymorphisms in the risk of developing late onset AD (LOAD), we analyzed the genotype and allele distributions of these 3 polymorphisms in 704 Han Chinese subjects. The minor alleles of the rs11792633 polymorphism within IL-33 was significantly associated with a reduced risk of LOAD (odds ratio [OR] = 0.73, p = 0.005). Furthermore, rs11792633 polymorphism was still strongly associated with LOAD (dominant model: OR = 0.67, p = 0.015; recessive model: OR 0.57, p = 0.021; additive model: OR = 0.71, p = 0.004) after adjusting for age, gender, and the apolipoprotein E (APOE) ε4 status. Our results support the evidence that genetic variants of IL-33 affect susceptibility to LOAD in Han Chinese.

[The evaluation of hydrocarbon potential generation for source rocks by near-infrared diffuse reflection spectra].

Near-infrared (NIR) and mid-infrared (MIR) diffuse reflection spectra were compared and evaluated for hydrocarbon potential generation of source rocks. Near-infrared diffuse reflectance often exhibits significant differences in the spectra due to the non-homogeneous distribution of the particles, so the signal-to-noise ratio of NIR is much lower than MIR It is too difficult to get accurate results by NIR without using a strong spectral preprocessing method to remove systematic noise such as base-line variation and multiplicative scatter effects. In the present paper, orthogonal signal correction (OSC) and an improved algorithm of it, i.e. direct orthogonal signal correction (DOSC), are used as different methods to preprocess both the NIR and MIR spectra of the hydrocarbon source rocks. Another algorithm, wavelet multi-scale direct orthogonal signal correction (WMDOSC), which is a combination of discrete wavelet transform (DWT) and DOSC, is also used as a preprocessing method. Then, the calibration model of hydrocarbon source rocks before and after pretreatment was established by interval partial least square (iPLS). The experimental results show that WMDOSC is more successfully applied to preprocess the NIR spectra data of the hydrocarbon source rocks than other two algorithms, and NIR performed as good as MIR in the analysis of hydrocarbon potential generation of source rocks with WMDOSC-iPLS pretreatment calibration model.