ABSTRACT
MIL77-3 is one component of antibody cocktail that is produced in our lab and represents an effective regimen for animals suffering from Zaire Ebolavirus (EBOV) infection. MIL77-3 is engineered to increase its affinity for the FcγRIIIa (CD16a) by deleting the fucose in the framework region. The potential effects of this modification on host immune responses, however, remain largely unknown. Herein, we demonstrated that MIL77-3 recognized secreted glycoproptein (sGP), produced by EBOV, and formed the immunocomplex to potently augment antibody-dependent cytotoxicity of human peripheral blood-derived natural killer cells (pNKs), including CD56dim and CD56bright subpopulations, in contrast to the counterparts (Mab114, rEBOV548, fucosylated MIL77-3). Intriguingly, this effect was not observed when NK92-CD16a cell line was utilized and restored by the addition of beads-coupled or membrane-anchored sGP in combination with MIL77-3. Furthermore, sGP bound to unrecognized receptors on T cells contaminated in pNKs rather than NK92-CD16a cells. Administration of beads-coupled sGP/MIL77-3 complex in mice elicited NK activation. Overall, this work reveals an immune-stimulating function of sGP/MIL77-3 complex by triggering cytotoxic activity of NK cells, highlighting the necessity to evaluate the potential impact of MIL77-3 on host immune reaction in clinical trials. IMPORTANCE: Zaire Ebolavirus (EBOV) is highly lethal and causes sporadic outbreaks. The passive administration of monoclonal antibodies (mAbs) represents a promising treatment regimen against EBOV. Mounting evidence has shown that the efficacy of a subset of therapeutic mAbs in vivo is intimately associated with its capacity to trigger NK activity, supporting glycomodification of Fc region of anti-EBOV mAbs as a putative strategy to enhance Fc-mediated immune effector function as well as protection in vivo. Our work here uncovers the potential harmful influence of this modification on host immune responses, especially for mAbs with cross-reactivity to secreted glycoproptein (sGP) (e.g., MIL77-3), and highlights it is necessary to evaluate the NK-stimulating activity of a fucosylated mAb engaged with sGP when a new candidate is developed.
ABSTRACT
Background: Salmonella is a significant pathogens of foodborne illness. The widespread use of antibiotics in clinical practice and animal husbandry has resulted in increasing drug resistance of Salmonella. In this study, we examined the serotype distribution and drug resistance of Salmonella in pediatric patients with diarrhea in Chenzhou City to provide a basis for the scientific control and rational use of antibiotics in clinical practice in relation to Salmonellosis. Methods: Stool Salmonella spp. were collected from patients younger than 18 years of age who met the definition for foodborne illness at two sentinel hospitals from 2017 through 2022 tested Salmonella, and a descriptive analysis of the epidemiologic characteristics. Salmonella strains isolated from the stool underwent serology and drug-sensitivity tests. The following 14 antibiotics were used for the drug-sensitivity tests: ampicillin (AMP), ampicillin/sulbactam (AMS), cefazolin (CFZ), cefoxitin, cefotaxime, ceftazidime, imipenem (IPM), tetracycline (TET), nalidixic acid, ciprofloxacin, chloramphenicol (CHL), gentamicin, trimethoprim/sulfamethoxazole (SXT), and azithromycin. Results: Samples from 1,263 pediatric with diarrhea, and Salmonella was detected in 221 (17.5%) of these patients. Positive test results were principally observed in the second and third quarters of each year, accounting for 21.1% and 19.6% of the cases, respectively. The infection rates of infants aged less than 12 months and toddlers aged 1-3 years with diarrhea were the highest at 21.3% and 17.8%, respectively. The 221 Salmonella strains were divided into 32 serotypes, of which Salmonella Typhimurium (S. Typhimurium) was the dominant strain (79.2%). The resistance rates to TET (86.9%), AMP (75.6%), AMS (58.4%), CFZ (55.7%), CHL (54.3%), and SXT (45.2%) predominated, and the differences in the drug-resistance rates to 1st-, 2nd-, and 3rd-generation cephalosporins were high (2.3-55.7%). Only 0.9% of the strains were resistant to IPM. The multidrug resistance (MDR) rate was 76.5% (169/221), and 48.9% (108/221) of the strains were resistant to five or more classes of antibiotics, of which the most common drug-resistance profile was AMP-AMS-TET-CHL-CFZ-SXT, accounting for 10.9% of Salmonella strains (24/221). Conclusions: Foodborne salmonellosis tended to occur during the summer and autumn in children, and infants and toddlers were more likely to develop salmonellosis than children in the other age groups. The dominant Salmonella serotype was S. Typhimurium. The drug-resistance rate of the tested strains was high, and the MDR problem was severe. We recommend that in the treatment of salmonellosis, antibiotics be selected rationally based on the drug-resistance status of local Salmonella resistance situation to ensure safety and efficacy.
ABSTRACT
Bladder cancer(BC) is one of the most prevalent cancers in the urinary tract, with high recurrence and fatality rates. Research indicates that go-ichi-ni-san complex subunit 1 (GINS1) crucially influences cancer progression by regulating DNA replication through cell cycle modulation. Thus, suppressing the active proliferation of cells in tumor tissues may require silencing GINS1. However, the consequences of GINS1 in bladder cancer aren't to be determined. In this paper, we examine the role and mechanism of GINS1 in the development of bladder cancer. GINS1 expression levels and prognostic relevance in bladder cancer were validated using Western blotting, immunohistochemistry, and Kaplan-Meier survival analysis. The influence of GINS1 on bladder cancer was investigated using a variety of approaches, including cell transfection, cell counts, transwell migrations, colony formation, and flow cytometry. Immunohistochemistry studies demonstrate that GINS1 expression is increased in bladder cancer tissues. GINS1 silencing resulted in an arrest of the cell cycle at the phase of G0/G1, which inhibited BC cell growth both in vitro and in vivo. GINS1 knockdown also hindered the AKT/mTOR pathway. Furthermore, increased GINS1 expression affects the cell cycle and stimulates the AKT/mTOR pathway, allowing BC to develop more quickly. Consequently, GINS1 occurs as a latent therapeutic target, particularly for individuals with BC.
Subject(s)
Cell Proliferation , Chromosomal Proteins, Non-Histone , Proto-Oncogene Proteins c-akt , Signal Transduction , TOR Serine-Threonine Kinases , Urinary Bladder Neoplasms , Urinary Bladder Neoplasms/pathology , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/metabolism , Humans , Proto-Oncogene Proteins c-akt/metabolism , Proto-Oncogene Proteins c-akt/genetics , TOR Serine-Threonine Kinases/metabolism , TOR Serine-Threonine Kinases/genetics , Chromosomal Proteins, Non-Histone/metabolism , Chromosomal Proteins, Non-Histone/genetics , Cell Proliferation/genetics , Animals , Cell Line, Tumor , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-myc/genetics , Gene Expression Regulation, Neoplastic , Mice , Disease Progression , Mice, Nude , Male , Female , Prognosis , Mice, Inbred BALB C , DNA-Binding ProteinsABSTRACT
Testicular torsion is a critical urologic condition for which testicular detorsion surgery is considered irreplaceable as well as the golden method of reversal. However, the surgical treatment is equivalent to a blood reperfusion process, and no specific drugs are available to treat blood reperfusion injuries. Salidroside (SAL) is one of the main effective substances in rhodiola, which has been shown to have antioxidant and antiapoptosis activities. This study was designed to determine whether SAL exerted a protective effect on testicular ischemia-reperfusion (I/R) injury. In this study, the I/R injury model of the testes and reoxygenation (OGD/R) model were used for verification, and SAL was administered at doses of 100 mg/kg and 0.05 mmol/L, respectively. After the experiments, the testicular tissue and TM4 Sertoli cells were collected for histopathologic and biochemical analyses. The results revealed that SAL improves the structure of testicular tissue and regulates the oxidation-antioxidation system. To further understand the molecular mechanisms of SAL in treating testicular I/R injuries, transcriptomics and metabonomics analyses were integrated. The results show that the Nfr2/HO-1/GPX4/ferroptosis signaling pathway is enriched significantly, indicating that it may be the main regulatory pathway for SAL in the treatment of testicular I/R injuries. Thereafter, transfection with Nrf2 plasmid-liposome was used to reverse verify that the Nfr2/HO-1/GPX4/ferroptosis signaling pathway was the main pathway for SAL anti-testicular I/R injury treatment. Thus, it is suggested that SAL can protect against testicular I/R injuries by regulating the Nfr2/HO-1/GPX4 signaling pathway to inhibit ferroptosis and that SAL may be a potential drug for the treatment of testicular I/R injuries.
ABSTRACT
Cell-free DNA (cfDNA), a burgeoning class of molecular biomarkers, has been extensively studied across a variety of biomedical fields. As a key component of liquid biopsy, cfDNA testing is gaining prominence in disease detection and management due to the convenience of sample collection and the abundant wealth of genetic information it provides. However, the broader clinical application of cfDNA is currently impeded by a lack of standardization in the preanalytical procedures for cfDNA analysis. A number of fundamental challenges, including the selection of appropriate preanalytical procedures, prevention of short cfDNA fragment loss, and the validation of various cfDNA measurement methods, remain unaddressed. These existing hurdles lead to difficulties in comparing results and ensuring repeatability, thereby undermining the reliability of cfDNA analysis in clinical settings. This review discusses the crucial preanalytical factors that influence cfDNA analysis outcomes, including sample collection, transportation, temporary storage, processing, extraction, quality control, and long-term storage. The review provides clarification on achievable consensus and offers an analysis of the current issues with the goal of standardizing preanalytical procedures for cfDNA analysis.
ABSTRACT
Natural killer (NK) cells represent key player in immune surveillance to eliminate transformed or malignant cells. One of mechanisms of action of NK cells is antibody-dependent cell-mediated cytotoxicity (ADCC) by recognizing tumor antigens on the surface of cancer cells. However, the heterogeneity of tumor antigens and the scarcity of membrane surface targets significantly restrict this strategy. Recently, we constructed a new cargo by tethering a low pH insertion peptide (pHLIP) to the C terminus of the ectodomain of programed death ligand-1 (PD-L1) and demonstrated its ability to modulate immune responses. Herein, the potential application of PD-L1-pHLIP in cancer therapy was determined. pHLIP tethering had no effect on the binding capacity of PD-L1 protein to an anti-PD-L1 antibody (i.e. avelumab). Association of pHLIP rendered PD-L1 segment display on the surface of cellular membrane in the acidic buffer instead of the neutral solution. Importantly, plate-coated or beads-coupled PD-L1-pHLIP enable robust activation and expression of cytotoxic mediators of NK cells via engaging avelumab. Overall, this work provides proof of concept that recombinant PD-L1 protein decorated on the cellular membrane driven by pHLIP in combination with appropriate monoclonal antibody has potentials to elicit NK cytotoxicity, which may represent a novel and promising therapeutic avenue in cancer.
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In July to August 2022, Pakistan suffered historic flooding while record-breaking heatwaves swept southern China, causing severe socioeconomic impacts. Similar extreme events have frequently coincided between two regions during the past 44 years, but the underlying mechanisms remain unclear. Using observations and a suite of model experiments, here, we show that the upper-tropospheric divergent wind induced by convective heating over Pakistan excites a barotropic anomalous anticyclone over eastern China, which further leads to persistent heatwaves. Atmospheric model ensemble simulation indicates that this dynamic pathway linking Pakistan flooding and East Asian heatwaves is intrinsic to the climate system, largely independent of global sea surface temperature forcing. This dynamic connection is most active during July to August when convective variability is large over Pakistan and the associated divergent flow excites barotropic Rossby waves that propagate eastward along the upper troposphere westerly waveguide. This robust waveguide and the time delay offer hopes for improved subseasonal prediction of extreme events in East Asia.
ABSTRACT
The aim of this systematic review is to comprehensively assess the weight loss (WL) practices in different combat sports (CS). The review protocol was preregistered with PROSPERO [CRD42023487196]. Three databases were searched (Web of Science, EBSCOhost, and PubMed) until 8 December 2023. Eligible studies had to meet five criteria: they must have been (a) written in English, (b) published in a peer-reviewed journal, (c) used a survey design to investigate the WL practices of CS athletes, and (d) reported the WL methods used by athletes using a five-point scale. Twenty-six studies (3994 participants from 14 CS) were included. This review found that (1) WL is highly prevalent in CS athletes; (2) many CS athletes started losing weight for competition as teenagers two to three times a year; (3) CS athletes usually lose <5% body weight in 7-14 days before competition; (4) increasing exercise and gradually dieting are the most commonly used WL methods; and (5) the influence of scientific practitioners on athletes is negligible. The habitual practices of CS athletes may be relatively harmless, but in some special cases, CS athletes also perform extreme WL practices. Scientific practitioners have little influence on their WL practices, which may form a vicious cycle of non-qualified influence.
Subject(s)
Athletes , Weight Loss , Humans , Martial Arts/physiology , Male , Female , Adolescent , Exercise , Wrestling/physiology , Diet, Reducing , Adult , Young Adult , Boxing , SportsABSTRACT
Marburg virus (MARV) is one of the filovirus species that cause deadly hemorrhagic fever in humans, with mortality rates up to 90%. Neutralizing antibodies represent ideal candidates to prevent or treat virus disease. However, no antibody has been approved for MARV treatment to date. In this study, we identified a novel human antibody named AF-03 that targeted MARV glycoprotein (GP). AF-03 possessed a high binding affinity to MARV GP and showed neutralizing and protective activities against the pseudotyped MARV in vitro and in vivo. Epitope identification, including molecular docking and experiment-based analysis of mutated species, revealed that AF-03 recognized the Niemann-Pick C1 (NPC1) binding domain within GP1. Interestingly, we found the neutralizing activity of AF-03 to pseudotyped Ebola viruses (EBOV, SUDV, and BDBV) harboring cleaved GP instead of full-length GP. Furthermore, NPC2-fused AF-03 exhibited neutralizing activity to several filovirus species and EBOV mutants via binding to CI-MPR. In conclusion, this work demonstrates that AF-03 represents a promising therapeutic cargo for filovirus-caused disease.
Subject(s)
Ebolavirus , Hemorrhagic Fever, Ebola , Marburgvirus , Humans , Antibodies, Viral , Molecular Docking Simulation , Glycoproteins , Hemorrhagic Fever, Ebola/prevention & control , Ebolavirus/chemistryABSTRACT
BACKGROUND: Hepatoid adenocarcinoma (HAC) is rare in the urinary system, with only 7 reported cases in upper urinary tract. This report aimed to explore the genetic characteristics of ureteral HAC for first time, and to describe the treatment prognosis of ureteral HAC. CASE PRESENTATION: We present a rare case of ureteral HAC in a 53-year-old female, showing elevated serum levels of AFP and CEA, prolonged chronic irritation may be an important cause of her ureteral HAC. Radical nephroureterectomy was performed, the serum levels of AFP and CEA decreased significantly, and metastasis in lymph nodes was found at 9 months after surgery, she had no related symptoms after 18 months postoperatively without adjuvant chemotherapy. Three driver somatic mutations in cancer were identified by NGS testing, including: TP53D281H, KMT2DL1211Ifs*2, KMT2DT1843Nfs*5, demonstrating that ureteral HAC has the similar mutational features to upper tract urothelial carcinoma. Homologous-recombination deficiency (HRD) was positive in this tumor with no mutations in HRD-related genes, which was possibly induced by the copy number deletion of SETD2 gene. CONCLUSIONS: We report a rare case of ureteral HAC with elevated serum levels of AFP and CEA. NGS testing demonstrated that ureteral HAC has the similar mutational features to upper tract urothelial carcinoma, which is an important guide for the diagnosis and treatment of ureteral HAC.
Subject(s)
Adenocarcinoma , Carcinoma, Transitional Cell , Ureter , Urinary Bladder Neoplasms , Female , Humans , Middle Aged , Ureter/surgery , Ureter/pathology , alpha-Fetoproteins , Urinary Bladder Neoplasms/pathology , Adenocarcinoma/genetics , High-Throughput Nucleotide SequencingABSTRACT
Marburg virus (MARV), one member of the Filoviridae family, cause sporadic outbreaks of hemorrhagic fever with high mortality rates. No countermeasures are currently available for the prevention or treatment of MARV infection. Monoclonal antibodies (mAbs) are promising candidates to display high neutralizing activity against MARV infection in vitro and in vivo. Recently, growing evidence has shown that immune effector function including antibody-dependent cell-mediated cytotoxicity (ADCC) is also required for in vivo efficacy of a panel of antibodies. Glyco-engineered methods are widely utilized to augment ADCC function of mAbs. In this study, we generated a fucose-knockout MARV GP-specific mAb named AF-04 and showed that afucosylation dramatically increased its binding affinity to polymorphic FcγRIIIa (F176/V176) compared with the parental AF-03. Accordingly, AF-04-mediated NK cell activation and NFAT expression downstream of FcγRIIIa in effector cells were also augmented. In conclusion, this work demonstrates that AF-04 represents a novel avenue for the treatment of MARV-caused disease.
Subject(s)
Marburgvirus , Antibodies, Monoclonal/therapeutic useABSTRACT
BACKGROUND: Conducting of clinical trials for rare diseases faces multiple challenges. Patients' cognition and attitude toward clinical trials are crucial, which may affect their participation and compliance, and affect the schedule of clinical trials eventually. OBJECTIVE AND METHOD: This study aims to explore the knowledge and attitudes of clinical trials of patients with rare diseases or patients' guardians. An anonymous cross-sectional survey was conducted from November 1, 2021, to November 30, 2021. A total of 1131 valid questionnaires were included. Among them, 417 were filled in by the patients themselves, and 714 were answered by the patients' guardians. RESULTS: The average score of clinical trial knowledge of the patients (8.25) was lower than that of the guardians (8.85). The willingness of the patients to participate in clinical trials was high (4.28), and the willingness of the patients' guardians was also high for patients to participate in clinical trials (4.35). The main promoting factors of clinical trial participation were the possibility of curing the disease. The main hindering factors of participation in clinical trials were lack of access to clinical trial information and concern about the safety and effectiveness of the trial drug. CONCLUSIONS: In conclusion, most respondents had some basic knowledge of clinical trials and high willingness to participate in clinical trials. But there were some cognitive deficiencies about clinical trials and many hindering factors to participate in clinical trials. Clinical trials of rare diseases should be patient-centered and truly meet the unmet clinical, psychological, and social needs of patients with rare diseases.
Subject(s)
Patient Participation , Rare Diseases , Humans , Cross-Sectional Studies , Rare Diseases/drug therapy , Patient Participation/psychology , Attitude , ChinaABSTRACT
BACKGROUND: Visual vertigo (VV) is a disease characterized by various visual signal-induced discomforts, including dizziness, unsteady balance, activity avoiding, and so forth. Distinguishing it from other kinds of dizziness is important because it needs the combination of visual training and vestibular rehabilitation together. However, there is no appropriate tool to diagnose VV in China, thus we would like to introduce an effective tool to China. OBJECTIVE: The aim of this study was to establish the reliability and validity of the Chinese version of visual vertigo analogue scale (VVAS-CH) and to achieve its crosscultural adaptation in order to promote its further usage in China. METHODS: A total of 1681 patients complaining of vertigo or dizziness were enrolled and they were asked to complete the VVAS-CH. The cross-cultural adaptation, reliability and construct validity of the VVAS-CH were determined. RESULTS: Split-half reliability was 0.939, showing a good reliability. Factor analysis identified only one common factor for the nine items that explained 64.83% of the total variance. Most fit indices reached acceptable levels, proving the good fit of the VVAS-CH model. CONCLUSIONS: The VVAS-CH validated in this study can be used as an effective tool for diagnosing and evaluating VV in patients whose native language is Chinese.
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Macrophage-hitchhiked arsenic/AB bionic preparations were developed to improve the therapeutic effect on liver cancer by means of the tumor-targeting ability of macrophages in vivo. In vitro and in vivo cellular uptake assays demonstrated that arsenic/AB, with negatively charged particles of around 100-200 nm size, could hitchhike to macrophages. Dissolution experiments of arsenic/AB showed that arsenic/AB could delay the release of arsenic and ensure the safety of macrophages during its transport. Histological examination confirmed the safety of the preparations for major organs. In vivo distribution experiment showed that the arsenic/AB bionic preparations could rapidly accumulate in tumors, and in vivo treatment experiment showed a significant tumor inhibition of arsenic/AB. The therapeutic mechanism of liver cancer might be that the arsenic/AB bionic preparations could inhibit tumor growth by reducing inflammatory response and inhibiting CSF1 secretion to block CSF1R activation to induce more differentiation of tumor-associated macrophages (TAMs) towards the anti-tumor M1 phenotype. Therefore, we concluded that the arsenic/AB bionic preparations could improve the distribution of arsenic in vivo by hitchhiking on macrophages as well as make it have tumor targeting and deep penetration abilities, thus increasing the therapeutic effect of arsenic on liver cancer with reduced side effects.
Subject(s)
Arsenic , Liver Neoplasms , Humans , Arsenic/pharmacology , Bionics , Liver Neoplasms/drug therapy , Macrophages , Phenotype , Tumor MicroenvironmentABSTRACT
Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a rare variant of the inflammatory myofibroblastic tumor, characterized by more aggressive clinical course and nuclear membrane staining of anaplastic lymphoma kinase (ALK) with ALK rearrangement. An elderly male came to the clinic because of an accidental abdominal mass. Abdominal and pelvic enhanced CT revealed a tumor apparently orginated from mesenchymal tissue. Subsequently, the abdominal mass and multiple organ resection was performed, and the mass was pathologically confirmed as EIMS. The patient developed Clavien-Dindo Grade III postoperative complications and was discharged after his condition improved. He received doxorubicin monotherapy after operation, but only one cycle was administered due to severe vomiting. The follow-up of 5 months after operation showed no evidence of recurrence. Given the rarity of EIMS, and ALk inhibitors have a long and robust effect on patients with ALK gene tumors, it is very important for clinicians to be familiar with the clinicopathological features of EIMS, which will contribute to the accurate diagnosis of EIMS and reduce misdiagnosis.
ABSTRACT
As a key problem of auto-vehicle applications, the goal of Anomaly Obstacle Segmentation (AOS) is to detect some strange and unexpected obstacles (possibly are unseen previously) on the drivable area, thereby equipping the semantic perceptual model to be tolerant of unknown things. Due to its practicality, recently AOS is drawing attentions and a long line of works are proposed to tackle the obstacles with almost infinite diversity. However, these methods usually focus less on the priors of driving scenarios and involve image re-generation or the retraining of perceptual model, which lead to large computational quantity or the degradation of perceptual performance. In this paper, we propose to pay more attention to the characteristics of driving scenarios, lowering the difficulty of this tricky task. A training-free retrieval based method is thereby proposed to distinguish road obstacles from the surrounding road texture by computing the cosine similarity based on their appearance features, and significantly outperforms methods of the same category by around 20 percentage points. Besides, we find that there is a deep relation between our method and self-attention mechanism, and as a result a novel Transformer evolves from our retrieval based method, further boosting the performance.
ABSTRACT
Purpose: Recent studies had shown that gut microbiota played a significant role in the development of the immune system and may affect the course of airway allergic disease. We conducted this study to determine unique gut microbial associated with allergic disease in children by shotgun gene sequencing. Methods: We collected fecal samples from children with allergic asthma (n = 23) and allergic rhinitis (n = 18), and healthy control (n = 19). The gut microbiota of specimens was analyzed by high-throughput metagenomic shotgun gene sequencing. Results: The intestinal microbiota of children with allergic asthma and allergic rhinitis was characterized by increased microbial richness and diversity. Simpson and Shannon were significantly elevated in children with allergic asthma. Principal coordinates analysis (PCoA) showed that the gut microbial communities cluster patterns of children with asthma or rhinitis were significantly different from those of healthy controls. However, no significant difference was found between asthma group and rhinitis group At the phylum level, higher relative abundance of Firmicutes was found in the allergic rhinitis group and allergic asthma group, while the level of Bacteroidetes was significantly lower. At the genus level, Corynebacterium, Streptococcus, Dorea, Actinomyces, Bifidobacterium, Blautia, and Rothia were significantly enriched in the allergic asthma group. Finally, a random forest classifier model selected 16 general signatures to discriminate the allergic asthma group from the healthy control group. Conclusion: In conclusion, children in the allergic rhinitis group and allergic asthma group had altered gut microbiomes in comparison with the healthy control group. Compared to healthy children, the gut microbiome in children with allergic diseases has higher pro-inflammatory potential and increased production of pro-inflammatory molecules.
ABSTRACT
High-quality graphene-based van der Waals superlattices are crucial for investigating physical properties and developing functional devices. However, achieving homogeneous wafer-scale graphene-based superlattices with controlled twist angles is challenging. Here, we present a flat-to-flat transfer method for fabricating wafer-scale graphene and graphene-based superlattices. The aqueous solution between graphene and substrate is removed by a two-step spinning-assisted dehydration procedure with the optimal wetting angle. Proton-assisted treatment is further used to clean graphene surfaces and interfaces, which also decouples graphene and neutralizes the doping levels. Twist angles between different layers are accurately controlled by adjusting the macroscopic stacking angle through their wafer flats. Transferred films exhibit minimal defects, homogeneous morphology, and uniform electrical properties over wafer scale. Even at room temperature, robust quantum Hall effects are observed in graphene films with centimetre-scale linewidth. Our stacking transfer method can facilitate the fabrication of graphene-based van der Waals superlattices and accelerate functional device applications.
ABSTRACT
A palladium-catalyzed regioselective and asymmetric allylic alkylation of azlactones with MBH carbonates has been developed with chiral oxalamide-phosphine ligands. The corresponding reaction afforded a range of optically active γ-arylidenyl glutamic acid derivatives bearing an α-chiral quaternary stereocenter in good yields with excellent linear regio- and high enantioselectivity. This protocol furnishes an alternative approach for the construction of enantio-enriched unnatural α-amino acid derivatives.