Developing Salt-Rejecting Evaporators for Solar Desalination: A Critical Review.

Solar desalination, a green, low-cost, and sustainable technology, offers a promising way to get clean water from seawater without relying on electricity and complex infrastructures. However, the main challenge faced in solar desalination is salt accumulation, either on the surface of or inside the solar evaporator, which can impair solar-to-vapor efficiency and even lead to the failure of the evaporator itself. While many ideas have been tried to address this ″salt accumulation″, scientists have not had a clear system for understanding what works best for the enhancement of salt-rejecting ability. Therein, for the first time, we classified the state-of-the-art salt-rejecting designs into isolation strategy (isolating the solar evaporator from brine), dilution strategy (diluting the concentrated brine), and crystallization strategy (regulating the crystallization site into a tiny area). Through the specific equations presented, we have identified key parameters for each strategy and highlighted the corresponding improvements in the solar desalination performance. This Review provides a semiquantitative perspective on salt-rejecting designs and critical parameters for enhancing the salt-rejecting ability of dilution-based, isolation-based, and crystallization-based solar evaporators. Ultimately, this knowledge can help us create reliable solar desalination solutions to provide clean water from even the saltiest sources.

Nontarget Discovery of Per- and Polyfluoroalkyl Sulfonyl Halides in Soils by Integration of Derivatization and Specific Fragment-Based Liquid Chromatography-High Resolution Mass Spectrometry Screening.

Though long recognized as synthetic precursors to other poly- and perfluoroalkyl substances (PFASs), most poly- and perfluoroalkyl sulfonyl halides (PASXs) cannot be directly measured and have generally received minimal attention. Inspired by the redox reaction between sulfonyl halide groups and p-toluenethiol in organic chemistry, we developed a novel nontarget analysis strategy for PASXs by intergrating derivatization and specific fragment-based liquid chromatography-high resolution mass spectrometry screening for m/z 82.961 [SO2F-] and m/z 95.934 [S2O2-]. By using this strategy, we discovered 11 PASXs, namely, perfluoroalkyl sulfonyl fluorides (5), polyfluoroalkyl sulfonyl fluorides (2), unsaturated perfluoroalkyl sulfonyl fluoride (1), and perfluoroalkyl sulfonyl chlorides (3) in soil samples collected from an abandoned fluorochemical manufacturing park. These average ∑PASXs concentrations were 1120 µg kg-1 (range: 9.7-9860 µg kg-1), which were very likely to be the key intermediates and undesired byproducts of electrochemical fluorination processes. Spatial variation in the mass ratio of ∑PASXs to ∑PFSAs (range: 0.7-795%) also indicates their different transportation pathways. More importantly, the decline of PASXs and increase of perfluoroalkyl sulfonates (when compared to a prior study at this site) suggest the continued hydrolysis of PASXs and the relatively fast environmental transformation rates in the abandoned fluorochemical park soils. Overall, these findings demonstrated the utility of a novel nontarget analysis strategy, which may change most PASXs from inferred precursors to measured intermediates and further could be adapted for structures, distribution, and transformation studies of PFASXs in other matrices.

Management of Nontraumatic Spontaneous Renal Hemorrhage (Wünderlich Syndrome) through Robotic-Assisted Laparoscopic Nephrectomy: A Case Series.

BACKGROUND Wünderlich syndrome (WS) is a rare diagnosis of nontraumatic spontaneous renal hemorrhage into the subcapsular, perirenal, or pararenal spaces. Prompt and effective intervention is necessary for an accurate pathological diagnosis and preservation of life. In the current literature, open surgery is the primary option when conservative treatment fails, but there can be serious trauma and corresponding consequences. Herein, we present 3 cases of Wünderlich syndrome managed by robot-assisted laparoscopic nephrectomy via a retroperitoneal approach. CASE REPORT Patient 1 was a 44-year-old woman with right flank pain for 6 h. Patient 2 was a 53-year-old woman with a history of diabetes who had pain in her right flank pain and nausea for 1 day. Patient 3 was a 45-year-old man with left flank pain for 1 day. All cases of WS were confirmed by CT. All 3 patients were treated with retroperitoneal robot-assisted nephrectomy after conservative treatment failed. Pathological examination confirmed that patient 1 had angiomyolipoma, and patients 2 and 3 had renal clear cell carcinoma. At the 9-month follow-up, renal function was good and no evidence of recurrence or metastasis has been detected. CONCLUSIONS These cases have highlighted the importance of the clinical history and imaging findings in the diagnosis of Wünderlich syndrome, and show that rapid management can be achieved using robot-assisted laparoscopic nephrectomy. However, it is crucial to have a skilled surgical team and adequate preoperative preparation.

[Genetic origin analysis of regions of homozygosity in three cases].

OBJECTIVE: To explore the genetic characteristics of three fetuses with regions of homozygosity (ROH). METHODS: Three fetuses with ROH diagnosed at Nanjing Drum Tower Hospital on December 2, 2020, March 19, 2021, and May 27, 2022, respectively were selected as the study subjects. Clinical data of the fetuses were collected. Chromosomal microarray analysis (CMA) was used to detect the ROH, and tandem repeat sequences (STR)-based multiplex PCR assay was used to identify the mosaicism status in fetus 1. RESULTS: Partial maternal isodisomy (iUPD) (16) was found in fetus 1, for which trisomy rescue may be accountable. Meanwhile, the fetus also has confined placental mosaicism (CPM) but not true mosaicism. The formation mechanism of ROH for fetus 2 was identity by descent. Partial maternal iUPD (7) was found in fetus 3, which may be due to gametic recombination. CONCLUSION: The ROH of the three fetuses were inherited from both parents or the mother. Above findings suggested that it is justified to detect ROH on imprinting disorder-related chromosomes when potential uniparental disomy is suspected.

The effects of different types of Tai Chi exercises on preventing falls in older adults: a systematic review and network meta-analysis.

OBJECTIVES: Few studies comparing the effects of different types of Tai Chi exercises on preventing falls in older adults. We compared the effects for finding an optimal intervention. METHODS: We searched 12 databases, including PubMed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI) and so on, from their inception to January 13, 2023. Randomized controlled trials incorporating different types of Tai Chi for preventing falls in older adults were included. The outcome measures were the incidence of falls and Berg Balance Scale (BBS). Network meta-analysis (NMA) was conducted using Stata 15.1 based on a frequentist framework. RESULTS: Seventeen trials were eligible, including 3470 participants and four types of Tai Chi. They were 24-form simplified Tai Chi (24-form), Yang style Tai Chi (Yang style), Sun style Tai Chi (Sun style) and Tai Chi exercise program (TCEP). In paired meta-analysis, for incidence of falls, 24-form (Relative Risk (RR) = 0.59, 95% confidence interval (CI) [0.40, 0.86]) was more efficient than the control group. For BBS outcome, 24-form (MD (mean difference) = 2.32, 95% CI [1.42, 3.22]) was better than the control group. In the NMA, the results of incidence of falls were as follows: 24-form > Yang style > Sun style > control > TCEP. The rank probability of BBS was as follows: 24-form > TCEP > Yang style > control. CONCLUSION: Among the four types of Tai Chi studied, the 24-form simplified Tai Chi has shown better efficacy than other types.

First-Principles Insights into Tungsten Semicarbide-Based Single-Atom Catalysts: Single-Atom Migration and Mechanisms in Oxygen Reduction.

Understanding the structural evolution of single-atom catalysts (SACs) in catalytic reactions is crucial for unraveling their catalytic mechanisms. In this study, we utilize density functional theory calculations to delve into the active phase evolution and the oxygen reduction reaction (ORR) mechanism of tungsten semicarbide-based transition metal SACs (TM1/W2C). The stable crystal phases and optimal surface exposures of W2C are identified by using ab initio atomistic thermodynamics simulations. Focusing on the W-terminated (001) surface, we screen 13 stable TM1/W2C variants, ultimately selecting Pt1/W2C(001) as our primary model. The surface Pourbaix diagram, mapped for this model under ORR conditions, reveals dynamic Pt1 migration on the surface, triggered by surface oxidation. This discovery suggests a novel single-atom evolution pathway. Remarkably, this single-atom migration behavior is also discerned in seven other group VIII SACs, enhancing both their catalytic activity and their stability. Our findings offer insights into the evolution of active phases in SACs, considering substrate structural arrangement, single-atom incorporation, and self-optimization of catalysts under various conditions.

[Variant analysis and prenatal diagnosis for two Chinese pedigrees affected with Spinal muscular atrophy with respiratory distress type 1].

OBJECTIVE: To explore the genetic etiology of two children with Spinal muscular atrophy with respiratory distress type 1 (SMARD1), and prevent the recurrence of birth defects. METHODS: Two unrelated families who had visited the Obstetrics and Gynecology Medical Center of Drum Tower Hospital from August to November 2021 were selected as the study subjects. Copy number of SMN1 gene exon 7 for the probands and their parents was detected by multiple ligation-dependent probe amplification (MLPA). and whole exome sequencing (WES) was carried out to screen the variants in the probands. Sanger sequencing was used to validate the variants within the families. Pathogenicity of the variants were predicted by bioinformatic analysis. Based on the results, prenatal diagnosis was performed for the fetuses. RESULTS: Both probands were found to harbor compound heterozygous variants of the IGHMBP2 gene, which were inherited from their parents. Among these, c.1144C>T, c.866delG and c.1666C>G were previously unreported and respectively classified as pathogenic variant (PVS1+PM2_Supporting+PP3+PP4), likely pathogenic variant (PM1+PM2_Supporting+PM4+PP3+PP4) and likely pathogenic variant (PM1+PM2_Supporting+PP2+PP3+PP4) based on the ACMG guidelines. Through preimplantation genetic testing for monogenic (PGT-M) and interventional prenatal diagnosis, transmission of the variants within the families was successfully blocked. CONCLUSION: The SMARD1 in both children may be attributed to the compound heterozygous variants of the IGHMBP2 gene, which has facilitated the genetic diagnosis and counselling, and provided reference for delineating the molecular pathogenesis of this disease.

[Prenatal diagnosis and phenotypic analysis of two fetuses harboring heterozygous deletions of SHOX gene].

OBJECTIVE: To explore the clinical manifestations of two fetuses harboring heterozygous deletions of the SHOX gene. METHODS: Two pregnant women who had presented at the Prenatal Diagnosis Center of Nanjing Drum Tower Hospital respectively on June 24, 2022 and July 27, 2022 were selected as the study subjects. In case 1, prenatal ultrasonography had shown short femur and intrauterine growth retardation of the fetus. Case 2 had a history of spontaneous abortions due to structural chromosomal aberrations. Fetus 1 had undergone a test for the FGFR3 gene, and both fetuses were subjected to single nucleotide polymorphism-based microarray (SNP array) analysis. RESULTS: After excluding the influence of FGFR3 gene variant, fetus 1 was found to harbor a heterozygous 883 kb deletion at Xpter or Ypter, whilst fetus 2 was found to harbor a 5.75 Mb deletion in the Xpter region. Both deletions have encompassed the SHOX gene. The origin of the deletion in fetus 1 was unknown, whilst that in fetus 2 was inherited from its mother. Fetus 1 has been delivered at term with a normal phenotype, and fetus 2 was not born yet. CONCLUSION: The intrauterine and postnatal phenotypes of fetuses may be predicted by combining the ultrasound finding, parental phenotype and results of CMA, and the results can facilitate genetic counseling and decision making over the pregnancy.

Lightweight and Real-Time Infrared Image Processor Based on FPGA.

This paper presents an FPGA-based lightweight and real-time infrared image processor based on a series of hardware-oriented lightweight algorithms. The two-point correction algorithm based on blackbody radiation is introduced to calibrate the non-uniformity of the sensor. With precomputed gain and offset matrices, the design can achieve real-time non-uniformity correction with a resolution of 640×480. The blind pixel detection algorithm employs the first-level approximation to simplify multiple iterative computations. The blind pixel compensation algorithm in our design is constructed on the side-window-filtering method. The results of eight convolution kernels for side windows are computed simultaneously to improve the processing speed. Due to the proposed side-window-filtering-based blind pixel compensation algorithm, blind pixels can be effectively compensated while details in the image are preserved. Before image output, we also incorporated lightweight histogram equalization to make the processed image more easily observable to the human eyes. The proposed lightweight infrared image processor is implemented on Xilinx XC7A100T-2. Our proposed lightweight infrared image processor costs 10,894 LUTs, 9367 FFs, 4 BRAMs, and 5 DSP48. Under a 50 MHz clock, the processor achieves a speed of 30 frames per second at the cost of 1800 mW. The maximum operating frequency of our proposed processor can reach 186 MHz. Compared with existing similar works, our proposed infrared image processor incurs minimal resource overhead and has lower power consumption.

Developmental Shifts in the Microbiome of a Cosmopolitan Pest: Unraveling the Role of Wolbachia and Dominant Bacteria.

Wolbachia bacteria (phylum Proteobacteria) are ubiquitous intracellular parasites of diverse invertebrates. In insects, coevolution has forged mutualistic associations with Wolbachia species, influencing reproduction, immunity, development, pathogen resistance, and overall fitness. However, the impact of Wolbachia on other microbial associates within the insect microbiome, which are crucial for host fitness, remains less explored. The diamondback moth (Plutella xylostella), a major pest of cruciferous vegetables worldwide, harbors the dominant Wolbachia strain plutWB1, known to distort its sex ratio. This study investigated the bacterial community diversity and dynamics across different developmental life stages and Wolbachia infection states in P. xylostella using high-throughput 16S rDNA amplicon sequencing. Proteobacteria and Firmicutes dominated the P. xylostella microbiome regardless of life stage or Wolbachia infection. However, the relative abundance of dominant genera, including an unclassified genus of Enterobacteriaceae, Wolbachia, Carnobacterium, and Delftia tsuruhatensis, displayed significant stage-specific variations. While significant differences in bacterial diversity and composition were observed across life stages, Wolbachia infection had no substantial impact on overall diversity. Nonetheless, relative abundances of specific genera differed between infection states. Notably, Wolbachia exhibited a stable, high relative abundance across all stages and negatively correlated with an unclassified genus of Enterobacteriaceae, Delftia tsuruhatensis, and Carnobacterium. Our findings provide a foundational understanding of the complex interplay between the host, Wolbachia, and the associated microbiome in P. xylostella, paving the way for a deeper understanding of their complex interactions and potential implications for pest control strategies.

Natural Disinfection-like Process Unveiled in Soil Microenvironments by Enzyme-Catalyzed Chlorination.

Substantial natural chlorination processes are a growing concern in diverse terrestrial ecosystems, occurring through abiotic redox reactions or biological enzymatic reactions. Among these, exoenzymatically mediated chlorination is suggested to be an important pathway for producing organochlorines and converting chloride ions (Cl-) to reactive chlorine species (RCS) in the presence of reactive oxygen species like hydrogen peroxide (H2O2). However, the role of natural enzymatic chlorination in antibacterial activity occurring in soil microenvironments remains unexplored. Here, we conceptualized that heme-containing chloroperoxidase (CPO)-catalyzed chlorination functions as a naturally occurring disinfection process in soils. Combining antimicrobial experiments and microfluidic chip-based fluorescence imaging, we showed that the enzymatic chlorination process exhibited significantly enhanced antibacterial activity against Escherichia coli and Bacillus subtilis compared to H2O2. This enhancement was primarily attributed to in situ-formed RCS. Based on semiquantitative imaging of RCS distribution using a fluorescence probe, the effective distance of this antibacterial effect was estimated to be approximately 2 mm. Ultrahigh-resolution mass spectrometry analysis showed over 97% similarity between chlorine-containing formulas from CPO-catalyzed chlorination and abiotic chlorination (by sodium hypochlorite) of model dissolved organic matter, indicating a natural source of disinfection byproduct analogues. Our findings unveil a novel natural disinfection process in soils mediated by indigenous enzymes, which effectively links chlorine-carbon interactions and reactive species dynamics.

Micro(nano)-plastics exposure induced programmed cell death and corresponding influence factors.

Plastic products have played an indispensable role in our daily lives for several decades, primarily due to their cost-effectiveness and unmatched convenience. Nevertheless, recent developments in nanotechnology have propelled our attention toward a distinct category of plastic fine particulates known as micro(nano)-plastics (MPs/NPs). The investigation of the cytotoxic effects of MPs/NPs has emerged as a central and burgeoning area of research in environmental toxicology and cell biology. In the scope of this comprehensive review, we have meticulously synthesized recent scientific inquiries to delve into the intricate interplay between MPs/NPs and programmed cell death mechanisms, which encompass a range of highly regulated processes. First, the signaling pathways and molecular mechanisms of different programmed death modalities induced by MPs/NPs were elaborated, including apoptosis, autophagy, necroptosis, ferroptosis, and pyroptosis. The causes of different programmed deaths induced by MPs/NPs, such as size, surface potential, functional group modification, aging, biological crown, and co-exposure of MPs/NPs are further analyzed. In contrast, the various cellular programmed death modes induced by MPs/NPs are not alone most of the time, and lastly, the connections between different cellular programmed death modes induced by MPs/NPs, such as interconversion, mutual promotion, and mutual inhibition, are explained. Our primary objective is to unveil the multifaceted toxicological implications of MPs/NPs on the intricate web of cellular fate and biological homeostasis. This endeavor not only broadens our understanding of the potential risks associated with MPs/NPs exposure but also underscores the urgent need for comprehensive risk assessments and regulatory measures in the context of environmental health.

Long-term pulmonary iron oxide nanoparticles exposure disrupts hepatic iron-lipid homeostasis and increases plaque vulnerability in ApoE-/- mice.

Iron oxide nanoparticles (Fe3O4 NPs) have attracted great attention due to their extensive applications, which warranted their environmental concerns. Although recent advances have proposed the relevance of Fe3O4 NPs to cardiovascular disease, the intrinsic mechanisms underlying the effects of NPs remain indistinct. ApoE-/- mice were chosen as a long-term exposure model to explore the immanent association between respiratory exposure to Fe3O4 NPs and the development of cardiovascular diseases. Pulmonary exposure to 20 nm and 200 nm Fe3O4 NPS resulted in significant lung injury, and pulmonary histopathological examination displayed inflammatory cell infiltration, septal thickening and alveolar congestion. Intriguingly, liver iron deposition and variations in the hepatic lipid homeostasis were found in Fe3O4 NPs-exposed mice, eventually leading to dyslipidemia, hinting the potential cardiovascular toxicity of Fe3O4 NPs. In addition, we not only found that Fe3O4 NPs exposure increased aortic plaque area, but also increased M1 macrophages in the plaque, which yielding plaque vulnerability in ApoE-/- mice Of note, 20 nm Fe3O4 NPs showed enhanced capability on the progression of atherosclerosis than 200 nm Fe3O4 NPs. This study may propose the potential mechanism for adverse cardiovascular disease induced by Fe3O4 NPs and provide convincing evidence for the safety evaluation of Fe3O4 NPs.

High-Efficiency and Emission-Tunable Inorganic Blue Perovskite Light-Emitting Diodes Based on Vacuum Deposition.

The fabrication of perovskite light-emitting diodes (PeLEDs) with vacuum deposition shows great potential and commercial value in realizing large-area display panel manufacturing. However, the electroluminescence (EL) performance of vacuum-deposited PeLEDs still lags behind the counterparts fabricated by solution process, especially in the field of blue PeLEDs. Here, the fabrication of high-quality CsPbBr3- x Clx film through tri-source co-evaporation is reported to achieve high photoluminescence quantum yield (PLQY). Compared with the conventional traditional dual-source co-evaporation, the tri-source co-evaporation method allows for freely adjustable elemental ratios, enabling the introduction of the lattice-matched Cs4 Pb(Br/Cl)6 phase with the quantum-limited effect into the inorganic CsPb(Br/Cl)3 emitter. By adjusting the phase distribution, the surface defects of the emitter can be effectively reduced, leading to better blue emission and film quality. Further, the effects of Cs/Pb ratio and Br/Cl ratio on the PLQY and carrier recombination dynamics of perovskite films are investigated. By optimizing the deposition rate of each precursor source, spectrally stable blue PeLEDs are achieved with tunable emission ranging from 468 to 488 nm. Particularly, the PeLEDs with an EL peak at 488 nm show an external quantum efficiency (EQE) of 4.56%, which is the highest EQE value for mixed-halide PeLEDs fabricated by vacuum deposition.

Metabolic and Microbial Profiling of Soil Microbial Community under Per- and Polyfluoroalkyl Substance (PFAS) Stress.

Per- and polyfluoroalkyl substances (PFAS) represent significant stress to organisms and are known to disrupt microbial community structure and function. Nevertheless, a detailed knowledge of the soil microbial community responding to PFAS stress at the metabolism level is required. Here we integrated UPLC-HRMS-based metabolomics data with 16S rRNA and ITS amplicon data across soil samples collected adjacent to a fluoropolymer production facility to directly identify the biochemical intermediates in microbial metabolic pathways and the interactions with microbial community structure under PFAS stress. A strong correlation between metabolite and microbial diversity was observed, which demonstrated significant variations in soil metabolite profiles and microbial community structures along with the sampling locations relative to the facility. Certain key metabolites were identified in the metabolite-PFAS co-occurrence network, functioning on microbial metabolisms including lipid metabolism, amino acid metabolism, and secondary metabolite biosynthesis. These results provide novel insights into the impacts of PFAS contamination on soil metabolomes and microbiomes. We suggest that soil metabolomics is an informative and useful tool that could be applied to reinforce the chemical evidence on the disruption of microbial ecological traits.

Case report: A novel homozygous variant in ZP3 is associated with human empty follicle syndrome.

Empty follicle syndrome (EFS) is a rare condition in female infertility. It is characterized by the inability to retrieve oocytes from visibly large, normally developing follicles in the ovaries, despite ovarian stimulation. The genetic factors contributing to this syndrome remain unclear. This study focused on patients who underwent three consecutive ovarian stimulation procedures for oocyte retrieval but experienced unsuccessful outcomes, despite the presence of observable large follicles. Ultrasound examinations were conducted to assess follicular development during each procedure. In order to investigate potential genetic causes, we performed whole exome sequencing on peripheral blood samples from the patient. Interestingly, we identified that this patient carries a homozygous mutation in the ZP3 genes. Within the ZP3 gene, we identified a homozygous variant [NM_001110354.2, c.176T>A (p.L59H)] specifically located in the zona pellucida (ZP) domain. Further analysis, including bioinformatics methods and protein structure modeling, was carried out to investigate the conservation of the ZP3L59H variant across different species. This homozygous variant exhibited a high degree of conservation across various species. Importantly, the homozygous ZP3L59H variant was associated with the occurrence of empty follicle syndrome in affected female patients. The homozygous ZP3L59H variant represents a newly discovered genetic locus implicated in the development of human empty follicle syndrome. Our findings contribute to a deeper understanding of the role of zona pellucida-related genes in infertility and provide valuable insights for the genetic diagnosis of female infertility.

[Analysis of a Chinese pedigree affected with van der Woude syndrome due to variant of IRF6 gene].

OBJECTIVE: To explore the genetic characteristics of a Chinese pedigree affected with van der Woude syndrome (VWS). METHODS: A proband who had visited the Drum Tower Hospital Affiliated to Nanjing University Medical School in May 2020 for "two previous pregnancies with cleft lip and palate" was selected as the study subject. Trio-whole exome sequencing (trio-WES) was carried out for the patient. Candidate variants were verified by Sanger sequencing of her pedigree members (8 individuals from four generations) and bioinformatic analysis. Chromosomal microarray analysis (CMA) was used to rule out copy number variations in the fetuses. RESULTS: Trio-WES revealed that the proband and her father had both harbored a heterozygous c.742G>T (p.G248C) missense variant of the IRF6 gene, for which her mother was of the wild type. The variant was located in a region with important functions and has not been reported previously. Prediction with several software suggested that it is likely to have a significant impact on the protein structure/function and is highly correlated with the specific phenotypes in this pedigree. Sanger sequencing confirmed co-segregation of the genotypes and phenotypes in the pedigree. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), this variant was rated as likely pathogenic (PM1+PM2_Supporting+PP1+PP3+PP4). Based on the above results, pre-implantation genetic diagnosis was carried out for the proband, which has led to birth of a healthy offspring with normal results for both site testing and CMA. CONCLUSION: The IRF6: c.742G>T (p.G248C) heterozygous variant probably underlay the VWS in this pedigree. Above finding has also enabled reproductive guidance for the proband.

Exceptional Thermochemical Stability of Graphene on N-Polar GaN for Remote Epitaxy.

In this study, we investigate the thermochemical stability of graphene on the GaN substrate for metal-organic chemical vapor deposition (MOCVD)-based remote epitaxy. Despite excellent physical properties of GaN, making it a compelling choice for high-performance electronic and light-emitting device applications, the challenge of thermochemical decomposition of graphene on a GaN substrate at high temperatures has obstructed the achievement of remote homoepitaxy via MOCVD. Our research uncovers an unexpected stability of graphene on N-polar GaN, thereby enabling the MOCVD-based remote homoepitaxy of N-polar GaN. Our comparative analysis of N- and Ga-polar GaN substrates reveals markedly different outcomes: while a graphene/N-polar GaN substrate produces releasable microcrystals (µCs), a graphene/Ga-polar GaN substrate yields nonreleasable thin films. We attribute this discrepancy to the polarity-dependent thermochemical stability of graphene on the GaN substrate and its subsequent reaction with hydrogen. Evidence obtained from Raman spectroscopy, electron microscopic analyses, and overlayer delamination points to a pronounced thermochemical stability of graphene on N-polar GaN during MOCVD-based remote homoepitaxy. Molecular dynamics simulations, corroborated by experimental data, further substantiate that the thermochemical stability of graphene is reliant on the polarity of GaN, due to different reactions with hydrogen at high temperatures. Based on the N-polar remote homoepitaxy of µCs, the practical application of our findings was demonstrated in fabrication of flexible light-emitting diodes composed of p-n junction µCs with InGaN heterostructures.

Unraveling the complexities of Cd-aniline composite pollution: Insights from standalone and joint toxicity assessments in a bacterial community.

Cadmium (Cd) and aniline frequently co-occur in industrial settings but have rarely been addressed as composite toxicants in terms of the overall toxicity despite extensive knowledge of the environmental impact of each individual pollutant. In this study, we attempt to assess the relation of individual and combined toxic effects of Cd and aniline using a bacterial consortium cultured from soils as a model system. Results showed that the consortial bacteria exhibited drastically stronger tolerance to stand-alone Cd and aniline in comparison to literature data acquired from single species studies. When occurring simultaneously, the joint toxicity displayed a concentration-dependent behavior that wasn't anticipated based on individual chemical tests. Specifically, additive effects manifested with Cd and aniline at their IC10s, but changed to synergistic when the concentrations increased to IC20, and finally transitioned into antagonistic at IC30s and beyond. In addition, co-occurring aniline appeared to have retarded the cellular accumulation of Cd while increasing the enzymatic activities of superoxide dismutase and catalase relative to that in Cd-alone treatments. Finally, the bacterial community experienced distinct compositional changes under solo and combined toxicities with several genera exhibiting inconsistent behavior between treatments of single and composite toxicants. Findings from this study highlight the complexity of bacterial response to composite pollutions and point to the need for more comprehensive references in risk and toxicology assessment at multi-chemical contamination sites.

Long-Term Exposure of Graphene Oxide Suspension to Air Leading to Spontaneous Radical-Driven Degradation.

Understanding the environmental transformation and fate of graphene oxide (GO) is critical to estimate its engineering applications and ecological risks. While there have been numerous investigations on the physicochemical stability of GO in prolonged air-exposed solution, the potential generation of reactive radicals and their impact on the structure of GO remain unexplored. In this study, using liquid-PeakForce-mode atomic force microscopy and quadrupole time-of-flight mass spectroscopy, we report that prolonged exposure of GO to the solution leads to the generation of nanopores in the 2D network and may even cause the disintegration of its bulk structure into fragment molecules. These fragments can assemble themselves into films with the same height as the GO at the interface. Further mediated electrochemical analysis supports that the electron-donating active components of GO facilitate the conversion of O2 to •O2- radicals on the GO surface, which are subsequently converted to H2O2, ultimately leading to the formation of •OH. We experimentally confirmed that attacks from •OH radicals can break down the C-C bond network of GO, resulting in the degradation of GO into small fragment molecules. Our findings suggest that GO can exhibit chemical instability when released into aqueous solutions for prolonged periods of time, undergoing transformation into fragment molecules through self-generated •OH radicals. This finding not only sheds light on the distinctive fate of GO-based nanomaterials but also offers a guideline for their engineering applications as advanced materials.