A feasible strategy for designing cytochrome P450-mimic sandwich-like single-atom nanozymes toward electrochemical CO2 conversion.

Carbon dioxide electroreduction (CO2ER) presents a promising strategy for environmentally friendly CO2 utilization due to its low energy consumption. Single-atom nanozymes (SANs), amalgamating the benefits of single-atom catalysts and nanozymes, have become a hot topic in catalysis. Inspired by the intricate structure of cytochrome P450, we designed 81 sandwich-like SANs using Group-VIII transition metals (TMN4-S-TM'N4) and evaluated their performance in CO2ER using density functional theory (DFT). Our investigation revealed that most SANs display superior catalytic activity and improved specific product selectivity in comparison to the Cu (211) surface. Notably, IrN4-S-TMN4 (TM = Co, Rh, Pd) exhibited selective CO2 reduction to CO with remarkable limiting potentials (UL) of -0.11, -0.07, and -0.09 V, respectively, demonstrating potential as artificial CO dehydrogenases. Furthermore, RuN4-S-RuN4 exhibited formate dehydrogenase-like activity, resulting in selective production of HCOOH at a UL of -0.10 V. Machine learning analysis elucidated that the exceptional activity and selectivity of these SANs stemmed from precise modulation of electron density on sulfur atoms, achieved by varying transition metals in the subsurface. Our research not only identifies exceptional SANs for CO2ER but also provides insights into innovative methods for regulating non-bonding interactions and achieving sustainable CO2 conversion.

Enhancing CO2 electroreduction performance through transition metal atom doping and strain engineering in γ-GeSe: a first-principles study.

The development of electrocatalysts that exhibit stability, high activity, and selectivity for CO2 reduction reactions (CO2RR) remains a significant challenge. Single-atom catalysts (SACs) hold promise in addressing this challenge due to their high atomic utilization efficiency. In this study, we explore the potential of monolayer γ-GeSe doped with transition metals, referred to as TM@γ-GeSe, for facilitating electrocatalytic CO2RR. Among the 26 TM@γ-GeSe SACs systematically designed, we have identified four stable transition metal catalysts (TM = Rh, Pd, Pt, and Au). Mechanistic investigations into the CO2RR pathways reveal exceptional electrocatalytic activity for Rh@γ-GeSe and Pd@γ-GeSe, with limiting potentials of -0.26 and -0.35 V, respectively. Particularly, Pd@γ-GeSe exhibits outstanding product selectivity toward formic acid. The introduction of strain engineering induces modifications in the catalytic activity and selectivity of Rh@γ-GeSe. Notably, a 1% tensile strain promotes formic acid as the preferred product, thereby improving the specific product selectivity of Rh@γ-GeSe. Conversely, compressive strain reduces CO2RR activity while enhancing the hydrogen evolution reaction, leading to a decrease in CO2RR selectivity. Furthermore, we use the work function as a descriptor to elucidate the underlying mechanism of strain tunability. We hope that our theoretical study will offer valuable insights for the design of catalysts based on γ-GeSe for electrocatalytic CO2RR.

Rapid Thalidomide Racemization Is Related to Proton Tunneling Reactions via Water Bridges.

Quantum mechanical tunneling (QMT) can play an important role in light element-related chemical reactions; however, its influence on racemization is not fully understood. Herein, we demonstrate that the role of QMT is decisive for rapid racemization of the well-known thalidomide molecule in aqueous environments, increasing the reaction rate constants of the most likely racemization pathways by 87-149 times at approximately body temperature and achieving good agreement between theoretical calculations and experimental observations. In addition, the kinetic isotope effect values fit well with those of previous experiments. These results are attributed to enhanced tunneling probability due to the alteration of potential barriers for proton transfer reactions via water bridges. This work highlights the significance of the QMT effect in racemization and its potential impact on drug safety, providing a fundamental perspective for understanding chirality-related issues in biological systems.

CO2 electroreduction performance of PtS2 supported single transition metal atoms: a theoretical study.

Electrocatalytic CO2 reduction is a sustainable strategy to convert CO2 into valuable carbon products. Atomically dispersed single-atom catalysts (SACs) have great potential as effective electrocatalysts for the CO2 reduction reaction (CO2RR). Transition metal dichalcogenides (TMDs) are considered to be a kind of promising SAC supports. In this work, ten different 3d TM single atoms (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) embedded in PtS2 with single S-vacancy (TM-PtS2) were designed by density functional theory (DFT) as candidate electrocatalysts for the CO2RR. Possible reaction pathways of CO2 reduction to different C1 products were systematically investigated. The results show that for all these TM-PtS2 SACs, higher selectivity was achieved for CO2 reduction to C1 products than for the competing hydrogen evolution. HCOOH is the most favorable reduction product on PtS2-Sv supported Sc, Ti, V, Cr, Mn, Fe and Cu SACs, while multiple C1 products are generated on Co-, Ni- and Zn-PtS2. In particular, it is found that Sc-, V-, Fe-, Co- and Cu-PtS2 exhibit higher electrocatalytic performance for the CO2RR than Cu(211). Therefore, these five SACs are promising CO2RR electrocatalysts.

Genetic characteristics of Chinese patients with hemorrhagic cerebrovascular disease.

BACKGROUND: We investigate the clinical and genetic characteristics of hemorrhagic cerebrovascular disease in order to provide a new theoretical basis for the prevention and treatment of hereditary cerebrovascular disease. METHOD: Three hereditary cerebral hemorrhage cases were analyzed retrospectively. The patients' families were surveyed, the clinical characteristics summarized, and gene polymorphisms investigated. RESULTS: Among the three cases, two patients had familial cerebral cavernous hemangiomas, and genetic testing revealed a heterozygous mutation in the CCM1 gene, with a deletion of base (T) in exon 15 (c.1542delT). The last patient had hereditary cerebral hemorrhage with amyloidosis, Finnish type, and the proband, his mother, and his daughter were found to have a heterozygous G duplicate mutation at position 100 in exon 1 of the GSN gene (c.100dupG). CONCLUSIONS: Future screening for genetic mutations associated with a high-risk of hereditary cerebral hemorrhage can help identify individuals at risk for this condition and thereby reduce the occurrence and progression of the disease. Such screening will further enhance the precision in preventing and treating cerebrovascular diseases.

Thrombotic thrombocytopenic purpura with neurological impairment: A Review.

The last 2 decades have witnessed considerable advances in our understanding of thrombotic thrombocytopenic purpura (TTP). However, there is still some ambiguity regarding the precise nature of this disease, especially with respect to nervous system involvement and the correct nomenclature. This article seeks to summarize the clinical manifestations of TTP and the associated diseases. We describe TTP complicated with cerebrovascular disease, spinal cord injury, posterior reversible encephalopathy syndrome (PRES), anxious-depressive symptoms, and cognitive decline. TTP with spinal cord injury is rarely reported. For better clarity, we discuss the case of a 57-year-old woman who was diagnosed with neuromyelitis optica spectrum disease (NMOSD) with atypical TTP. The concurrent occurrence of NMOSD and TTP in this patient is consistent with the characteristics of acquired autoimmunity. We highlight the importance of early recognition of TTP in patients with atypical presentation who may not have the expected clinical or laboratory findings. This is particularly important in TTP patients with other concomitant autoimmune diseases or age-related comorbid conditions.

Paroxysmal limbs jitter accompanied by different imaging findings in a Chinese family with spinocerebellar ataxia 40: Clinical and neuroimaging studies.

Spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group accompanied by obvious pontocerebellar limitations. This condition is complex both genetically and phenotypically, making it difficult to describe all the variants simultaneously. Herein, we report a proband from a Chinese mainland family who was admitted to our hospital with paroxysmal limbs jitter and head-shaking. She had experienced broad-based gait, dysarthria, dysmetria, and tremor for about 20 years. Similar clinical symptoms were observed in the daughter, sister and deceased father of this proband. Magnetic resonance imaging showed varying degrees of cerebellar atrophy. The results of whole-exome sequencing (WES) indicated that the three affected members carried the c.590G>A mutation in the CCDC88C gene. Based on the diagnosis of SCA40, this proband was treated with aggressive management. Unfortunately, the proband died of suffocation due to laryngeal oedema. Paroxysmal limbs jitter may be a rare phenotype of SCA40 and may occur as a result of involuntary motion which should be differentiated from chorea and epilepsy. In patients with SCA40, pontocerebellar atrophy occurs to varying degrees. Even in the same family, the multiple patients diagnosed did not all exhibit pontocerebellar atrophy. Furthermore, WES is indispensable for the identification of some atypical phenotypes of SCA40.

Fluorescence polarization assay improves the rapid detection of human brucellosis in China.

BACKGROUND: Brucellosis is an infectious-allergic zoonotic disease caused by bacteria of the genus Brucella. Early diagnosis is the key to preventing, treating, and controlling brucellosis. Fluorescence polarization immunoassay (FPA) is a new immunoassay for relatively rapid and accurate detection of antibodies or antigens based on antigen-antibody interaction. However, there is no report on FPA-based detection of human brucellosis in China. Therefore, this study is to evaluate the value of FPA for the diagnosis of human brucellosis in China. METHODS: We recruited 320 suspected brucellosis cases who had the clinical symptoms and epidemiological risk factors between January and December, 2019. According to China Guideline for Human Brucellosis Diagnosis, the Rose Bengal test (RBT) was used for the screening test, and the serum agglutination test (SAT) was used as the confirmatory test. Brucellosis was confirmed only if the results of both tests were positive. Additionally, FPA and enzyme linked immune sorbent assay (ELISA) were compared with SAT, and their sensitivity, specificity, coincidence rate and consistency coefficient (Kappa value) as diagnostic tests were analyzed individually and in combination. The optimal cut-off value of FPA was also determined using the receiver operator characteristic (ROC) curve. RESULTS: The optimum cut-off value of FPA was determined to be 88.5 millipolarization (mP) units, with a sensitivity of 94.5% and specificity of 100.0%. Additionally, the coincidence rate with the SAT test was 96.6%, and the Kappa value (0.9) showed excellent consistency. The sensitivity and specificity of FPA and ELISA combined were higher at 98.0% and 100.0% respectively. CONCLUSIONS: When the cut-off value of FPA test is set at 88.5 mP, it has high value for the diagnosis of brucellosis. Additionally, when FPA and ELISA are combined, the sensitivity of diagnosis is significantly improved. Thus, FPA may have potential in the future as a diagnostic method for human brucellosis in China.

Unveiling the potential of superalkali cation Li3+ for capturing nitrogen.

The potential of the superalkali cation Li3+ for capturing N2 and its behavior in gaseous nitrogen have been theoretically studied at the MP2/6-311+G(d) level. The evolution of structures and stability of the Li3+(N2)n (n = 1-7) complexes shows that the N2 molecules tend to bind to different vertices of the Li3+ core, and that Li3+ might have the capacity to capture up to twelve nitrogen molecules in the first coordination shell. Based on natural population and molecular orbital analyses, Li3+ keeps its superatom identity in the lowest-lying Li3+(N2)n (n = 1-4) complexes. The change in the Gibbs free energies of possible fragmentation channels also indicates the thermodynamic stability of Li3+ in the (N2)n clusters when n ≤ 4. Different from the case of Li3+(H2O)n, where the electrostatic interaction is dominant, the electrostatic and polarization components are found to make nearly equal contributions to Li3+(N2)n complex formation. In addition, it can be concluded that the superalkali cation Li3+ surpasses heavy alkali metal cations in capturing N2 molecules, since it has a larger binding energy with N2 than Na+ and K+ ions.

Adsorption and activation of molecular oxygen over atomic copper(I/II) site on ceria.

Supported atomic metal sites have discrete molecular orbitals. Precise control over the energies of these sites is key to achieving novel reaction pathways with superior selectivity. Here, we achieve selective oxygen (O2) activation by utilising a framework of cerium (Ce) cations to reduce the energy of 3d orbitals of isolated copper (Cu) sites. Operando X-ray absorption spectroscopy, electron paramagnetic resonance and density-functional theory simulations are used to demonstrate that a [Cu(I)O2]3- site selectively adsorbs molecular O2, forming a rarely reported electrophilic η2-O2 species at 298 K. Assisted by neighbouring Ce(III) cations, η2-O2 is finally reduced to two O2-, that create two Cu-O-Ce oxo-bridges at 453 K. The isolated Cu(I)/(II) sites are ten times more active in CO oxidation than CuO clusters, showing a turnover frequency of 0.028 ± 0.003 s-1 at 373 K and 0.01 bar PCO. The unique electronic structure of [Cu(I)O2]3- site suggests its potential in selective oxidation.

Single-walled carbon nanotubes enhance the immune protective effect of a bath subunit vaccine for pearl gentian grouper against Iridovirus of Taiwan.

Iridovirus of Taiwan (TGIV) has been threatening the grouper farming since 1997, effective prophylaxis method is urgently needed. Subunit vaccine was proved to be useful to against the virus. Bath is the simplest method of vaccination and easy to be administrated without any stress to fish. In this research, we constructed a prokaryotic expression vector of TGIV's major capsid protein (MCP) to acquire the vaccine. Single-walled carbon nanotubes (SWCNTs) were used as the carrier to enhance the protective effect of bath vaccination for juvenile pearl gentian grouper (bath with concentrations of 5, 10, 20 mg/L for 6 h). Virus challenge was done after 28 days. Survival rates were calculated after 14 days. The level of antibody, activities of related enzymes in serums and expression of immune-related genes in kidneys and spleens were test. The results showed that vaccine with SWCNTs as carrier induced a higher level of antibody than that without. In addition, the activities of related enzymes (acid phosphatase, alkaline phosphatase, superoxide dismutase) and the expression of immune-related genes (Mx1, IgM, TNFαF, Lysozyme, CC chemokine 1, IL1-ß, IL-8) had a significantly increase. What's more, higher survival rates (42.10%, 77.77%, 89.47%) were provided by vaccine with SWCNTs than vaccine without SWCNTs (29.41%, 38.09%, 43.75%). This study suggests that the protective effect of vaccine that against TGIV with the method of bath vaccination could be enhanced by SWCNTs and SWCNTs could be a potential carrier for other subunit vaccines.

DFT study on the mechanism of bimetallic Pd-Zn-catalyzed cycloaddition of alkynyl aryl ethers with internal alkynes.

The reaction mechanism of bimetallic Pd-Zn-catalyzed cycloaddition of alkynyl aryl ethers with internal alkynes has been studied theoretically. Besides cycloaddition reaction, the dimerization of alkynyl aryl ethers was also considered. Both C6H5OC[triple bond, length as m-dash]CSiiPr3 and C6H5OC[triple bond, length as m-dash]CSiMe3 were chosen as the substrates. The reactions involve C-H activation of the substrate, acetic acid rotation, H transformation, MeC[triple bond, length as m-dash]CMe or substrate insertion into the Pd-phenyl bond and reductive elimination steps. It is found that cycloaddition is favored for C6H5OC[triple bond, length as m-dash]CSiiPr3, while dimerization is preferred for C6H5OC[triple bond, length as m-dash]CSiMe3, because the steric repulsion between two bulky SiiPr3 groups is relatively large and the steric repulsion between two small SiMe3 groups is relatively small. In addition, besides C6H5OC[triple bond, length as m-dash]CSiiPr3, four other substrates C6H5CH2C[triple bond, length as m-dash]CSiiPr3, C6H5C(O)C[triple bond, length as m-dash]CSiiPr3, C6H5SC[triple bond, length as m-dash]CSiiPr3 and C6H5N(H)C[triple bond, length as m-dash]CSiiPr3 have been calculated as the substrates for cycloaddition reaction with MeC[triple bond, length as m-dash]CMe. Among the five substrates, C6H5OC[triple bond, length as m-dash]CSiiPr3 has the lowest energy barrier (29.9 kcal mol-1), consistent with the experimental observation that C6H5OC[triple bond, length as m-dash]CSiiPr3 is the appropriate substrate for successful cycloaddition.

On single-electron magnesium bonding formation and the effect of methyl substitution.

The complexes formed between MgX2 (X = F, H) molecules and alkyl radicals Y [Y = CH3, CH2CH3, CH(CH3)2, and C(CH3)3] have been characterized by using quantum chemical methods. The binding distance in all cases is less than the sum of vdW radii of Mg and C, indicating the formation of a non-covalent interaction, namely single-electron magnesium bond. Energy decomposition analysis reveals that electrostatic and polarization contributions are the major components responsible for the stability of the studied complexes. According to interaction energy, atoms in molecules, and independent gradient model analyses, methyl substitution on electron donor Y imposes a positive effect on its complexation with MgX2. When compared with other nonbonded interactions, the single-electron magnesium bond is found to have strength comparable to those of the single-electron beryllium bond and π-magnesium bond.

Neuroacanthocytosis with unusual clinical features: A case report.

RATIONALE: Neuroacanthocytosis (NA) is a heterogeneous group of inherited neurodegenerative disorders characterized by misshapen spiculated erythorcytes and symptoms that resemble Huntington's disease. PATIENT CONCERNS: A 59-year-old female who developed hyperkinetic involuntary movements that became progressively more obvious during the course of a year. DIAGNOSES: Acanthocytes were observed in a peripheral blood smear. The patient had elevated levels of serum creatine kinase (CK). Gene sequencing did not reveal a genetic mutation. INTERVENTIONS: The patient was administered oral tiapride, alprazolam, B1 and B12 Vitamins. OUTCOMES: After 2 months of treatment the patient's symptoms were obviously alleviated. At the 6 month follow-up, the patient could feed herself and walk without assistance. LESSONS: The NA syndrome is extremely rare. It may be identified in the clinic based on abnormal orofacial movement, chorea, cognitive decline, elevated CK levels, and acanthocytosis. If available, protein- or genetic-based testing may provide a confirmatory diagnosis.

Limbic encephalitis associated with antibodies against the α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic acid receptor: a case report.

We report a case of a 51-year-old man with limbic encephalitis (LE) associated with antibodies against the α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic acid receptor (AMPAR). The patient presented with anterograde memory loss for 2 months. Cranial magnetic resonance and electroencephalogram were normal. AMPAR antibodies were found in blood serum and cerebrospinal fluid. All other test results were unremarkable. CT scans found a tumor in the right lobus superior pulmonis. A CT-guided needle biopsy was performed and pathological results showed small cell lung cancer (SCLC). The patient was diagnosed with LE associated with AMPAR antibodies and SCLC. Three months after immunotherapy and tumor removal, patient's memory was partially restored. We recommend that AMPAR antibodies should be detected in patients with classic LE with or without tumor. Prompt treatment of the tumor and immunotherapy are important.

Purulent meningitis caused by Rhodococcus equi: A case report.

RATIONALE: Purulent meningitis refers infection of the subarachnoid space by various purulent bacteria and the corresponding inflammation of the leptomeninges. However, purulent meningitis due to Rhodococcus equi is extremely rare. PATIENT CONCERNS: A 40-year-old man presented with fever and intermittent headache for 6 days. Two hours prior to admission, he developed epileptic seizures. DIAGNOSES: Brain computed tomography and magnetic resonance imaging showed intracerebral malacic lesions. Bacterial culture of cerebrospinal fluid revealed the presence of R. equi. A diagnosis of purulent meningitis caused by R. equi was made. INTERVENTIONS: The patient was treated with intravenous meropenem (1000 mg every 8 hours) for 19 days; then he was discharged and instructed to continue the intravenous meropenem for two weeks. After a follow-up period of 2 months, the patient had recovered completely. OUTCOMES: After a follow-up period of 2 months, the patient had recovered completely. LESSONS: Central nervous system infection caused by R. equi is rare. Early bacterial culture of CSF is important for timely diagnosis. With sufficient antibiotic therapy, the prognosis can be favorable.

Bubble-wrap carbon: an integration of graphene and fullerenes.

Graphene and fullerene, two types of C allotropes with very different structures and properties, have attracted considerable attention from the scientific community as new forms of carbon for several decades. It will be a great advantage to combine the geometrical features of the two. Herein, we report a series of novel two-dimensional carbon allotropes that possess fullerene-like hollow structures (bubbles) embedded in a graphene sheet. These carbon allotropes are both thermally and dynamically stable. Calculations using hybrid functionals show that these two-dimensional carbon allotropes could be metals or semiconductors depending on the size and the pattern of the bubbles. The band gap can be as large as 1.66 eV. Due to the unique atomic configuration, some bubble-wrap carbons have unusual negative Poisson's ratios. The combination of graphene and fullerenes provides an appealing approach to design carbon-based materials with dexterous properties. For example, the insertion of the metal atoms inside the bubbles may greatly enhance the functions of such materials in photovoltaics and catalysis.

Honeycomb Boron Allotropes with Dirac Cones: A True Analogue to Graphene.

We propose a series of planar boron allotropes with honeycomb topology and demonstrate that their band structures exhibit Dirac cones at the K point, the same as graphene. In particular, the Dirac point of one honeycomb boron sheet locates precisely on the Fermi level, rendering it as a topologically equivalent material to graphene. Its Fermi velocity (vf) is 6.05 × 105 m/s, close to that of graphene. Although the freestanding honeycomb B allotropes are higher in energy than α-sheet, our calculations show that a metal substrate can greatly stabilize these new allotropes. They are actually more stable than α-sheet sheet on the Ag(111) surface. Furthermore, we find that the honeycomb borons form low-energy nanoribbons that may open gaps or exhibit strong ferromagnetism at the two edges in contrast to the antiferromagnetic coupling of the graphene nanoribbon edges.

Higher frequency of brain abnormalities in neuromyelitis optica spectrum disorder patients without primary Sjögren's syndrome.

Neuromyelitis optica spectrum disorder often co-exists with primary Sjögren's syndrome. We compared the clinical features of 16 neuromyelitis optica spectrum disorder patients with (n = 6) or without primary Sjögren's syndrome (n = 10). All patients underwent extensive clinical, laboratory, and MRI evaluations. There were no statistical differences in demographics or first neurological involvement at onset between neuromyelitis optica spectrum disorder patients with and without primary Sjögren's syndrome. The laboratory findings of cerebrospinal fluid oligoclonal banding, serum C-reactive protein, antinuclear autoantibody, anti-Sjögren's-syndrome-related antigen A antibodies, anti-Sjögren's-syndrome-related antigen B antibodies, and anti-Sm antibodies were significantly higher in patients with primary Sjögren's syndrome than those without. Anti-aquaporin 4 antibodies were detectable in 67% (4/6) of patients with primary Sjögren's syndrome and in 60% (6/10) of patients without primary Sjögren's syndrome. More brain abnormalities were observed in patients without primary Sjögren's syndrome than in those with primary Sjögren's syndrome. Segments lesions (> 3 centrum) were noted in 50% (5/10) of patients without primary Sjögren's syndrome and in 67% (4/6) of patients with primary Sjögren's syndrome. These findings indicate that the clinical characteristics of neuromyelitis optica spectrum disorder patients with and without primary Sjögren's syndrome are similar. However, neuromyelitis optica spectrum disorder patients without primary Sjögren's syndrome have a high frequency of brain abnormalities.

Psychiatric symptoms and limb tremors associated with central pontine myelinolysis: A case of alcoholism without hyponatremia.

Central pontine myelinolysis (CPM), also known as osmotic demyelination syndrome, is a rare demyelinating disorder characterized by the loss of myelin in the center of the basis pontis. In this case report, an alcoholic patient with CPM and acquired demyelinating lesion of the basis pontis is described. The patient is a 70 year-old woman who presented with intermittent psychiatric symptoms and limb tremors following two months of alcohol abuse. During admission, magnetic resonance imaging (MRI) revealed hyperintensity on T2 weighted images and fluid-attenuated inversion-recovery imaging in the central pons without contrast enhancement. The patient's symptoms gradually improved following conservative treatment with vitamins B1 and B12. The one month follow-up MRI showed a significant reduction of the pontine injury.