Curvature-Induced Electron Spin Catalysis with Carbon Spheres.

Here, we report curvature-induced electron spin catalysis by using solid carbon spheres as catalysts, which were synthesized using positive curvature molecular hexabromocyclopentadiene as a precursor molecule, following a radical coupling mechanism. The curvature spin of carbon is regarded as an overlapping state of σ- and π-radical, which is identified by the inverse Laplace transform of pulse-electron paramagnetic resonance. The growth mechanism of carbon spheres abiding by Kroto's model, is supported by the density functional theory study of thermodynamics and kinetics calculations. The solid carbon spheres present excellent catalytic behaviour of oxidation coupling of amines to form corresponding imines with the conversion of >99%, selectivity of 98.7%, and yield of 97.7%, which is attributed to the predominantly curvature-induced electron spin catalysis of carbon, supported by the calculation of oxygen adsorption energy. This work proposes a view of curvature-induced spin catalysis of carbon, which opens up a research direction for curvature-induced electron spin catalysis.

Electron Spin Catalysis with Graphene Belts.

Here, we report kinetic studies using electron spin resonance spectroscopy on spin catalysis reactions caused by using graphene belts which were synthesized by a radical coupling method. The results show that σ-type free radical species provide the dominant sites for catalytic activity through the spin-spin interaction, although there are some other influencing factors. The spin catalysis mechanism can be applied both in the oxygen reduction reaction (ORR) and in organic synthesis. The graphene belt spin catalyst shows excellent performance with a high ORR half-wave potential of 0.81 V and long-term stability with almost no loss of activity after 50 000 cycles in alkaline media. It also shows excellent performance in a benzylamine coupling with molecular oxygen to generate the corresponding imine at an average conversion of ≈97.7 % and an average yield of ≈97.9 %. This work opens up a new research direction for understanding aerobic processes in the field of spin catalysis.

Early detection of T-cell lymphoma with T follicular helper phenotype by RHOA mutation analysis.

Angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma with T follicular helper phenotype (PTCL-TFH) are a group of complex clinicopathological entities that originate from T follicular helper cells and share a similar mutation profile. Their diagnosis is often a challenge, particularly at an early stage, because of a lack of specific histological and immunophenotypic features, paucity of neoplastic T cells and prominent polymorphous infiltrate. We investigated whether the lymphoma-associated RHOA Gly17Val (c.50G>T) mutation, occurring in 60% of cases, is present in the early "reactive" lesions, and whether mutation analysis could help to advance the early diagnosis of lymphoma. The RHOA mutation was detected by quantitative polymerase chain reaction with a locked nucleic acid probe specific to the mutation, and a further peptide nucleic acid clamp oligonucleotide to suppress the amplification of the wild-type allele. The quantitative polymerase chain reaction assay was highly sensitive and specific, detecting RHOA Gly17Val at an allele frequency of 0.03%, but not other changes in Gly17, nor in 61 controls. Among the 37 cases of AITL and PTCL-TFH investigated, RHOA Gly17Val was detected in 62.2% (23/37) of which 19 had multiple biopsies including preceding biopsies in ten and follow-up biopsies in 11 cases. RHOA Gly17Val was present in each of these preceding or follow-up biopsies including 18 specimens that showed no evidence of lymphoma by combined histological, immunophenotypic and clonality analyses. The mutation was seen in biopsies 0-26.5 months (mean 7.87 months) prior to the lymphoma diagnosis. Our results show that RHOA Gly17Val mutation analysis is valuable in the early detection of AITL and PTCL-TFH.

Inhibition of ALK2 with bicyclic pyridyllactams.

Activin receptor-like kinase 2 (ALK2) has been implicated as a key target in multiple rare diseases. Herein, we describe the design of a novel bicyclic lactam series of potent and selective ALK2 inhibitors. This manuscript details an improvement in potency of two orders of magnitude from the initial bicyclic structure as well as a two-fold improvement in cellular potency from the original monocyclic inhibitor. Furthermore, we provide a detailed strategy for progressing this project in the future.

Discovery of a novel 2-spiroproline steroid mimetic scaffold for the potent inhibition of 11ß-HSD1.

11ß-hydroxysteroid dehydrogenase 1 (11ß-HSD1) has been identified as the primary enzyme responsible for the activation of hepatic cortisone to cortisol in specific peripheral tissues, resulting in the concomitant antagonism of insulin action within these tissues. Dysregulation of 11ß-HSD1, particularly in adipose tissues, has been associated with a variety of ailments including metabolic syndrome and type 2 diabetes mellitus. Therefore, inhibition of 11ß-HSD1 with a small nonsteroidal molecule is therapeutically desirable. Implementation of a scaffold-hopping approach revealed a 3-point pharmacophore for 11ß-HSD1 that was utilized to design a 2-spiroproline derivative as a steroid mimetic scaffold. Reiterative optimization provided valuable insight into the bioactive conformation of our novel scaffold and led to the discovery of several leads, such as compounds 39 and 51. Importantly, deleterious hERG inhibition and pregnane X receptor induction were mitigated by the introduction of a 4-hydroxyl group to the proline ring system.

Discovery of 1'-(1-phenylcyclopropane-carbonyl)-3H-spiro[isobenzofuran-1,3'-pyrrolidin]-3-one as a novel steroid mimetic scaffold for the potent and tissue-specific inhibition of 11ß-HSD1 using a scaffold-hopping approach.

11ß-hydroxysteroid dehydrogenase 1 (11ß-HSD1) has been identified as the primary enzyme responsible for the activation of hepatic cortisone to cortisol in specific peripheral tissues resulting in the concomitant antagonism of insulin action within these tissues. Dysregulation of 11ß-HSD1, particularly in adipose tissues, has been associated with metabolic syndrome and type 2 diabetes mellitus. Therefore, inhibition of 11ß-HSD1 with a small nonsteroidal molecule is therapeutically desirable. Implementation of a scaffold-hopping approach revealed a three-point pharmacophore for 11ß-HSD1 that was utilized to design a steroid mimetic scaffold. Reiterative optimization provided valuable insight into the bioactive conformation of our novel scaffold and led to the discovery of INCB13739. Clinical evaluation of INCB13739 confirmed for the first time that tissue-specific inhibition of 11ß-HSD1 in patients with type 2 diabetes mellitus was efficacious in controlling glucose levels and reducing cardiovascular risk factors.

Novel tumour-infiltrating lymphocyte-related risk stratification based by flow cytometry for patients with de novo angioimmunoblastic T cell lymphoma.

Tumour-infiltrating lymphocytes (TILs) account for a large proportion of tumour microenvironment (TME) in angioimmunoblastic T cell lymphoma (AITL), and at present the significance of TIL in TME of AITL remains unclear. Overall, 50 de novo AITL patients undergoing lymph node flow cytometry from 2014 to 2019 were retrospectively analysed to assess the relationship between TILs and AITL prognosis. We found that high TIL-Bs (≥ 42.4%, p = 0.004) and high CD4:CD8 (≥ 0.85, p = 0.024) were independent favourable prognostic factors for de novo AITL in univariate or multivariate analyses. New TIL-related risk stratification was established based on TIL-Bs and CD4:CD8 factors. Patients in the low-risk group (TIL-Bs ≥ 42.4% and CD4:CD8 ≥ 0.85) had significantly better overall survival than the high-risk (TIL-Bs < 42.4% and CD4:CD8 < 0.85) (p < 0.001) or intermediate-risk group (TIL-Bs ≥ 42.4% and CD4:CD8 < 0.85 or TIL-Bs < 42.4% and CD4:CD8 ≥ 0.85) (p = 0.011). To our knowledge, our cohort is the largest one focusing on the TILs in de novo cases of AITL by analysing lymph node samples using flow cytometry, which is the first time to comprehensively consider humoral immunity and cellular immunity influence on AITL. Our new risk stratification was valuable and useful in evaluating prognosis of AITL and guiding immunotherapy strategies.

Angioimmunoblastic T-cell lymphoma contains multiple clonal T-cell populations derived from a common TET2 mutant progenitor cell.

Angioimmunoblastic T-cell lymphoma (AITL) is a neoplastic proliferation of T follicular helper cells with clinical and histological presentations suggesting a role of antigenic drive in its development. Genetically, it is characterized by a stepwise acquisition of somatic mutations, with early mutations involving epigenetic regulators (TET2, DNMT3A) and occurring in haematopoietic stem cells, with subsequent changes involving signaling molecules (RHOA, VAV1, PLCG1, CD28) critical for T-cell biology. To search for evidence of potential oncogenic cooperation between genetic changes and intrinsic T cell receptor (TCR) signaling, we investigated somatic mutations and T-cell receptor ß (TRB) rearrangement in 119 AITL, 11 peripheral T-cell lymphomas with T follicular helper phenotype (PTCL-TFH), and 25 PTCL-NOS using Fluidigm polymerase chain reaction (PCR) and Illumina MiSeq sequencing. We confirmed frequent TET2, DNMT3A, and RHOA mutations in AITL (72%, 34%, 61%) and PTCL-TFH (73%, 36%, 45%) and showed multiple TET2 mutations (2 or 3) in 57% of the involved AITL and PTCL-TFH. Clonal TRB rearrangement was seen in 76 cases with multiple functional rearrangements (2-4) in 18 cases (24%). In selected cases, we confirmed bi-clonal T-cell populations and further demonstrated that these independent T-cell populations harboured identical TET2 mutations by using BaseScope in situ hybridization, suggesting their derivation from a common TET2 mutant progenitor cell population. Furthermore, both T-cell populations expressed CD4. Finally, in comparison with tonsillar TFH cells, both AITL and PTCL-TFH showed a significant overrepresentation of several TRB variable family members, particularly TRBV19*01. Our findings suggest the presence of parallel neoplastic evolutions from a common TET2 mutant haematopoietic progenitor pool in AITL and PTCL-TFH, albeit to be confirmed in a large series of cases. The biased TRBV usage in these lymphomas suggests that antigenic stimulation may play an important role in predilection of T cells to clonal expansion and malignant transformation. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Parsaclisib Is a Next-Generation Phosphoinositide 3-Kinase δ Inhibitor with Reduced Hepatotoxicity and Potent Antitumor and Immunomodulatory Activities in Models of B-Cell Malignancy.

The clinical use of first-generation phosphoinositide 3-kinase (PI3K)δ inhibitors in B-cell malignancies is hampered by hepatotoxicity, requiring dose reduction, treatment interruption, and/or discontinuation of therapy. In addition, potential molecular mechanisms by which resistance to this class of drugs occurs have not been investigated. Parsaclisib (INCB050465) is a potent and selective next-generation PI3Kδ inhibitor that differs in structure from first-generation PI3Kδ inhibitors and has shown encouraging anti-B-cell tumor activity and reduced hepatotoxicity in phase 1/2 clinical studies. Here, we present preclinical data demonstrating parsaclisib as a potent inhibitor of PI3Kδ with over 1000-fold selectivity against other class 1 PI3K isozymes. Parsaclisib directly blocks PI3K signaling-mediated cell proliferation in B-cell lines in vitro and in vivo and indirectly controls tumor growth by lessening immunosuppression through regulatory T-cell inhibition in a syngeneic lymphoma model. Diffuse large B-cell lymphoma cell lines overexpressing MYC were insensitive to proliferation blockade via PI3Kδ signaling inhibition by parsaclisib, but their proliferative activities were reduced by suppression of MYC gene transcription. Molecular structure analysis of the first- and next-generation PI3Kδ inhibitors combined with clinical observation suggests that hepatotoxicity seen with the first-generation inhibitors could result from a structure-related off-target effect. Parsaclisib is currently being evaluated in multiple phase 2 clinical trials as a therapy against various hematologic malignancies of B-cell origin (NCT03126019, NCT02998476, NCT03235544, NCT03144674, and NCT02018861). SIGNIFICANCE STATEMENT: The preclinical properties described here provide the mechanism of action and support clinical investigations of parsaclisib as a therapy for B-cell malignancies. MYC overexpression was identified as a resistance mechanism to parsaclisib in DLBCL cells, which may be useful in guiding further translational studies for the selection of patients with DLBCL who might benefit from PI3Kδ inhibitor treatment in future trials. Hepatotoxicity associated with first-generation PI3Kδ inhibitors may be an off-target effect of that class of compounds.

Epidemiological and genetic investigation of a cluster of cases of severe fever with thrombocytopenia syndrome bunyavirus.

BACKGROUND: To analyze and discuss the transmission route of a cluster of cases of severe fever with thrombocytopenia syndrome bunyavirus (SFTSV). METHOD: We performed an epidemiological investigation and a genetic analysis of patients with severe fever with thrombocytopenia syndrome (SFTS) caused by SFTSV, their close contacts and the surrounding population. RESULTS: We found that all patients had contact with the blood of the first patient. The comparison of gene sequences in the three isolated SFTSV strains showed that the strains were closely related. Six close contacts and nine individuals in the surrounding population were positive for SFTSV IgM antibody. CONCLUSION: We suspect that the cluster outbreak was transmitted via blood and that the natural reservoir host of SFTSV exists in the patients' environment.

INCB040093 Is a Novel PI3Kδ Inhibitor for the Treatment of B Cell Lymphoid Malignancies.

Phosphatidylinositol 3-kinase delta (PI3Kδ) is a critical signaling molecule in B cells and is considered a target for development of therapies against various B cell malignancies. INCB040093 is a novel PI3Kδ small-molecule inhibitor and has demonstrated promising efficacy in patients with Hodgkin's lymphoma in clinical studies. In this study, we disclose the chemical structure and the preclinical activity of the compound. In biochemical assays, INCB040093 potently inhibits the PI3Kδ kinase, with 74- to >900-fold selectivity against other PI3K family members. In vitro and ex vivo studies using primary B cells, cell lines from B cell malignancies, and human whole blood show that INCB040093 inhibits PI3Kδ-mediated functions, including cell signaling and proliferation. INCB040093 has no significant effect on the growth of nonlymphoid cell lines and was less potent in assays that measure human T and natural killer cell proliferation and neutrophil and monocyte functions, suggesting that the impact of INCB040093 on the human immune system will likely be restricted to B cells. INCB040093 inhibits the production of macrophage-inflammatory protein-1ß (MIP-1beta) and tumor necrosis factor-ß (TNF-beta) from a B cell line, suggesting a potential effect on the tumor microenvironment. In vivo, INCB040093 demonstrates single-agent activity in inhibiting tumor growth and potentiates the antitumor growth effect of the clinically relevant chemotherapeutic agent, bendamustine, in the Pfeiffer cell xenograft model of non-Hodgkin's lymphoma. INCB040093 has a favorable exposure profile in rats and an acceptable safety margin in rats and dogs. Taken together, data presented in this report support the potential utility of orally administered INCB040093 in the treatment of B cell malignancies.

Tuning the K+ Concentration in the Tunnels of α-MnO2 To Increase the Content of Oxygen Vacancy for Ozone Elimination.

α-MnO2 is a promising material for ozone catalytic decomposition and the oxygen vacancy is often regarded as the active site for ozone adsorption and decomposition. Here, α-MnO2 nanowire with tunable K+ concentration was prepared through a hydrothermal process in KOH solution. High concentration K+ in the tunnel can expand crystal cell and break the charge balance, leading to a lower average oxidation state (AOS) of Mn, which means abundant oxygen vacancy. DFT calculation has also proven that the samples with higher K+ concentration exhibit lower formation energy for oxygen vacancy. Due to the enormous active oxygen vacancies existing in the α-MnO2 nanowire, the lifetime of the catalyst (corresponding to 100% ozone removal rate, 25 °C) is increased from 3 to 15 h. The FT-IR results confirmed that the accumulation of intermediate oxygen species on the catalyst surface is the main reason why it is deactivated after long time reaction. In this work, the performance of the catalyst has been improved because the abundant active oxygen vacancies are fabricated by the electrostatic interaction between oxygen atoms inside the tunnels and the introduced K+, which offers us a new perspective to design a high efficiency catalyst and may promote manganese oxide for practical ozone elimination.

[Serotonergic neurons in the median raphe nucleus mediate anxiety- and depression-like behavior].

Serotonin (5-hydroxtryptamine, 5-HT), one of the central neurotransmitters, is the most important modulator for emotion regulation, sensory processing, cognitive control, etc. The serotonergic neurons are limited in amount and mainly distributed in the dorsal raphe nucleus (DR) and the median raphe nucleus (MR) in the midline of the brain stem. Previous studies mainly focused on the function of 5-HT neurons in the DR, but little is known about 5-HT neurons in MR. In the present study, with Pet1-Cre transgenic mice and DREADDs technology, we specifically activated or silenced 5-HT neurons in the MR, and aimed to explore their roles in anxiety- and depressive-like behaviors. The results showed that silencing 5-HT neurons in the MR decreased anxiety-like behaviors in the open field and elevated plus maze tasks. Inhibition of 5-HT neurons in the MR decreased depressive-like behaviors in the sucrose preference and forced swim test, while activation of 5-HT neurons in the MR enhanced depressive-like behaviors in the sucrose preference test. These results suggest that the 5-HT neurons in the MR play a key role in regulating anxiety- and depression-like behaviors.

The Effect of Electrical Impedance Matching on the Electromechanical Characteristics of Sandwiched Piezoelectric Ultrasonic Transducers.

For achieving the power maximum transmission, the electrical impedance matching (EIM) for piezoelectric ultrasonic transducers is highly required. In this paper, the effect of EIM networks on the electromechanical characteristics of sandwiched piezoelectric ultrasonic transducers is investigated in time and frequency domains, based on the PSpice model of single sandwiched piezoelectric ultrasonic transducer. The above-mentioned EIM networks include, series capacitance and parallel inductance (I type) and series inductance and parallel capacitance (II type). It is shown that when I and II type EIM networks are used, the resonance and anti-resonance frequencies and the received signal tailing are decreased; II type makes the electro-acoustic power ratio and the signal tailing smaller whereas it makes the electro-acoustic gain ratio larger at resonance frequency. In addition, I type makes the effective electromechanical coupling coefficient increase and II type makes it decrease; II type make the power spectral density at resonance frequency more dramatically increased. Specially, the electro-acoustic power ratio has maximum value near anti-resonance frequency, while the electro-acoustic gain ratio has maximum value near resonance frequency. It can be found that the theoretically analyzed results have good consistency with the measured ones.

PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration.

Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

[Photoluminescence of Silicon Nitride-Based ZnO Thin Film Developed with RF Magnetron Sputtering].

Owing to its merits of high corrosion resistance, high temperature stability as well as good mechanical strength etc., silicon nitride membrane (SiN) has been widely used as the experimental carrier of transmission electron microscope (TEM), scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-Ray spectroscopy (EDX) and other characterization. In particular, SiN can be used as a low disturbing background for SEM observation. However, the poor luminescent property of SiN thin film has restricted its wide application in fluorescent devices. In order to enhance the fluorescence efficiency of silicon nitride membrane, a series of ZnO films were prepared on a SiNx film substrate with radio frequency magnetron sputtering (RF magnetron sputtering) technology during the experiment. Samples were then non-situ and in-situ annealed in nitrogen atmosphere, respectively. Then, atomic force microscope (AFM), scanning electron microscopy (SEM) and Raman spectroscopy (Raman) were applied to study the microstructure and photoluminescence (PL) properties of the prepared films. This paper also systemically studies the luminescence of the prepared thin films. The results show that, luminescent intensity increases after sputtering, while annealing further promoted the grain growth, a substantial increase in crystallization behavior and a decrease in grain boundary. The microstructure and luminescence properties of ZnO/SiN thin films prepared by RF magnetron sputtering were significantly influenced by annealing method. Compared with the SiNx film, near the band edge of the intrinsic emission intensity (about 380 nm) of untempered ZnO/SiNx films and N(2) atmosphere ex-situ annealed ZnO/SiNx films were increased by more than 7.7 times and 34.0 times. Compared with non-situ annealed films, in-situ annealed films contained more oxygen vacancy defects, thus showing a stronger visible light PL intensity. In-situ annealed films exhibited a higher photoluminescence capacity during the wavelength from 425 to 600 nm of visible light. These results can help to optimize the preparation parameters of silicon nitride based ZnO fluorescent films.

Polyaniline/Carbon Nitride Nanosheets Composite Hydrogel: A Separation-Free and High-Efficient Photocatalyst with 3D Hierarchical Structure.

A polyaniline (PANI)/carbon nitride nanosheets (CNNS) composite hydrogel with 3D hierarchical nanostructure is synthesized via in situ polymerization. The 3D hierarchical structure is robust and stable, making the composite hydrogel separation-free and easy to recycling. It is highly excellent in removing organic pollutant for PANI/CNNS composite hydrogel on account of the cooperation of adsorptive preconcentration and the following photocatalytic oxidation. Pollutants are first adsorbed and concentrated into the 3D hierarchical nanostructure of the composite hydrogel. Then the pollutants are in situ oxidized via photocatalysis. The promoted photocatalytic performance can be mainly ascribed to the outstanding interfacial charge separation and photoelectrochemical performance. A new idea of the construction of 3D hierarchical photocatalysts is presented, which can be applied in the sustainability field.

Gastrointestinal Lymphoma in Southwest China: Subtype Distribution of 1,010 Cases Using the WHO (2008) Classification in a Single Institution.

UNLABELLED: The gastrointestinal tract (GIT) is the most common anatomic site of extranodal non-Hodgkin lymphoma (NHL) involvement. The classification criteria of lymphoma have changed in recent decades, and few large-sample studies regarding subtype analysis of lymphoma have been performed in this site. AIM: Therefore, the present study was conducted to analyze the histological subtype distribution of the GIT. METHOD: All patients in a single institution with a diagnosis of primary NHL in the GIT were enrolled between January 2007 and April 2014. The patients were categorized according to the WHO (2008) classification of tumors of hematopoietic and lymphoid tissue. RESULT: A total of 1,010 eligible cases diagnosed as NHL were collected in this study. The male:female ratio was 1.7:1 and the median age was 55 years. The percent of patients with lymphoma involvement in the stomach was 52% (n = 522), and the remaining 48% (n = 484) had intestinal tract involvement. Histologically, diffuse large B cell lymphoma (DLBCL) was the most common subtype in all of the GIT lymphoma cases, and was also the most common subtype in cases involving the stomach (78%) and the intestinal tract (53%). The incidence of DLBCL and mucosa-associated lymphoid tissue lymphoma in the stomach was significantly higher than the incident in the intestinal tract (p < 0.01). T and NK cell lymphoma was significantly more common in the intestinal tract than in the stomach (p < 0.01). Extranodal NK/T cell lymphoma nasal type (ENKTL-N) was the most common subtype of T and NK cell lineage lymphoma in GIT and was also the second most common intestinal tract-involved lymphoma. CONCLUSION: DLBCL was the most frequent lymphoma in the stomach and in the intestinal tract. T and NK cell lineage lymphoma had a higher occurrence in the intestinal tract than in the stomach. ENKTL-N was the most frequent subtype of lymphoma derived from NK/T cell lineage, and was the second most common lymphoma among all intestinal tract lymphomas.

A highly efficient g-C3N4/SiO2 heterojunction: the role of SiO2 in the enhancement of visible light photocatalytic activity.

SiO2, an insulator, hardly has any photocatalytic acitivity due to its intrinsic property, and it is generally used as a hard template to increase the surface area of catalysts. However, in this work, we found that the surface state of the insulator SiO2 can promote the migration of photogenerated charge carriers, leading to the enhancement of the photooxidation ability of graphitic carbon nitride (g-C3N4). A one-pot calcination method was employed to prepare g-C3N4/SiO2 composites using melamine and SiO2 as precursors. The composites present considerably high photocatalytic degradation activities for 2,4-dichlorophenol (2,4-DCP) and rhodamine B (RhB) under visible light (λ > 420 nm) irradiation, which are about 1.53 and 4.18 times as high as those of bulk g-C3N4, respectively. The enhancement of the photocatalytic activity is due to the fact that the introduction of the insulator SiO2 in g-C3N4/SiO2 composites can greatly improve the specific surface area of the composites; more importantly, the impurity energy level of SiO2 can help accelerate the separation and transfer of electron-hole pairs of g-C3N4. Electron paramagnetic resonance (EPR) spectroscopy and trapping experiments with different radical scavengers show that the main active species of g-C3N4 are superoxide radicals, while holes also play a role in photodegradation. For g-C3N4/SiO2-5, besides superoxide radicals and holes, the effect of hydroxyl radicals was greatly improved. Finally, a possible mechanism for the photogenerated charge carrier migration of the g-C3N4/SiO2 photocatalyst was proposed.

The formation of heterointerface defects in Au/Cu films on Si substrates under direct current in a vacuum ultraviolet environment.

Au/Cu metallic films were deposited on p-Si(100) substrates with and without an Au upper layer by magnetron sputtering. The defect formation and nanoscale interfacial evolution at the Au/Cu and Cu/Si interfaces were studied by using Auger electron spectroscopy (AES) and high resolution transmission electron microscopy (HRTEM). The results showed that an increase in defects at the heterointerfaces and in the surface layer was induced by the effect of a direct current (DC) in a vacuum ultraviolet (UV) environment, which could provide more channels for the removal of atoms. The directed migration of atomic clusters in the films was caused by the effect of the DC, which also aggravated the defects' expansion and led to the formation of Au-Cu intermetallic compounds (IMCs). In addition, the voids formed at the interface between the Au/Cu films and the Si substrates were found to be mainly related to the generation of the material Au2Cu3.