Effect of Oxide on Surface Tension of Molten Metal

Oxides as one of the commonly activating fluxes used in active tungsten inert gas welding (A-TIG welding) can dramatically increase the penetration depth to 2–4 times that of conventional welding. Using the oscillation principle of inviscid fluid, a robust method is developed to measure the average surface tension of molten metal during A-TIG welding for four different oxide activating fluxes of B2O3, TiO2, SiO2, and MgO. The experimental results suggest that the oxygen released from the decomposition of oxides is the dominant factor contributing to the change of the surface tension, which can result in the change of the temperature coefficient from negative to positive and alter the Marangoni convection, leading to the increase in the penetration depth. However, oxygen of small amount or large amount has a negligible effect on the sign change of the temperature coefficient. For oxides of low melting points, the interaction between the electrons outside the arc and the neutral particles (atoms and molecules) formed from the dissolution of the oxides causes the constriction of the arc; for oxides of high melting points, the decrease of the spot area in the anode due to high resistivity of the oxides leads to the constriction of the arc

Preformed Pt nanoparticles supported on nanoshaped CeO2 for total propane oxidation

Pt-based catalysts have been widely used for the removal of short-chain volatile organic compounds (VOCs), such as propane. In this study, we synthesized Pt nanoparticles with a size of ca. 2.4 nm and loaded them on various fine-shaped CeO2 with different facets to investigate the effect of CeO2 morphology on the complete oxidation of propane. The Pt/CeO2-o catalyst with {111} facets exhibited superior catalytic activity compared to the Pt/CeO2-r catalyst with {110} and {100} facets. Specifically, the turnover frequency (TOF) value of Pt/CeO2-o was 1.8 times higher than that of Pt/CeO2-r. Moreover, Pt/CeO2-o showed outstanding long-term stability during 50 h. X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed that the excellent performance of Pt/CeO2-o is due to the prevalence of metallic Pt species, which promotes C–C bond cleavage and facilitates the rapid removal of surface formate species. In contrast, a stronger metal–support interaction in Pt/CeO2-r leads to easier oxidation of Pt species and the accumulation of intermediates, which is detrimental to the catalytic activity. Our work provides insight into the oxidation of propane on different nanoshaped Pt/CeO2 catalysts.Peer ReviewedPostprint (published version

A wafer-scale two-dimensional platinum monosulfide ultrathin film via metal sulfurization for high performance photoelectronics

2D nonlayered materials have attracted enormous research interests due to their novel physical and chemical properties with confined dimensions. Platinum monosulfide as one of the most common platinum-group minerals has been less studied due to either the low purity in the natural product or the extremely high-pressure conditions for synthesis. Recently, platinum monosulfide (PtS) 2D membranes have emerged as rising-star materials for fundamental Raman and X-ray photoelectron spectral analysis as well as device exploration. However, a large-area homogeneous synthesis route has not yet been proposed and released. In this communication, we report a facile metal sulfurization strategy for the synthesis of a 4-inch wafer-scale PtS film. Enhanced characterization tools have been employed for thorough analysis of the crystal structure, chemical environment, vibrational modes, and atomic configuration. Furthermore, through theoretical calculations the phase diagram of the Pt–S compound has been plotted for showing the successful formation of PtS in our synthesis conditions. Eventually, a high-quality PtS film has been reflected in device demonstration by a photodetector. Our approach may shed light on the mass production of PtS films with precise control of their thickness and homogeneity as well as van der Waals heterostructures and related electronic devices

Visible light photocatalytic decarboxylative monofluoroalkenylation of α-amino acids with gem-difluoroalkenes

A novel, efficient and general visible-light photocatalytic decarboxylative monofluoroalkenylation of N-protected α-amino acids with gem-difluoroalkenes is reported, affording the corresponding α-amino monofluoroalkenes.</p

Oral mucosal manifestations of Sweet’s syndrome: a case report and literature review

Objective To explore the oral mucosal manifestations of Sweet’s syndrome and provide a reference for its early detection and correct diagnosis. Methods The oral mucosal manifestations of a 60-year-old female patient with Sweet’s syndrome are described in detail, followed by a discussion of the related literature. Results The patient had skin erythema of both lower extremities, which was accompanied by oral mucosal ulceration and pain for 3 days. The patient presented with mild cutaneous lesions and diffuse large-scale erosion in the oral mucosa with obvious pain. During the onset of the disease, the patient was accompanied by fever with a temperature of 38.5&#x00B0;C. After visiting the Department of Stomatology, laboratory tests showed an increase in C-reactive protein (35.2 mg/L) and an accelerated erythrocyte sedimentation rate (77.00 mm/h). Scattered red plaques and mild tenderness were observed in the knees and lower limbs. Histopathological examination of the skin lesions revealed scattered infiltration of immature neutrophils across the entire dermis. The patient responded well to glucocorticoid therapy. According to the clinical signs and laboratory examination, combined with the lesion histopathological results, a diagnosis of Sweet’s syndrome was given. The patient was administered 1 mL compound Betamethasone injection only once intramuscularly. In the meantime, the patient was asked to gargle with compound chlorhexidine solution and topically apply recombinant bovine basic fibroblast growth factor solution to the damaged mucosa three times a day for 1 week. After 4 days of medication, the patient’s body temperature had returned to normal and the oral lesions were significantly reduced. After 2 weeks, the erythema in the leg and knee had almost all subsided, and the oral mucosal lesions had disappeared. The patient was followed up 6 months after treatment, with no recurrence of skin lesions. After 2 years of follow-up, the disease was stable with no recurrence. A review of the relevant literature shows that Sweet’s syndrome is a rare inflammatory reactive dermatosis with unknown etiology, which can be divided into three clinical types: specific, tumor-related, and drug-induced. The male/female prevalence ratio is 1:4. The salient clinical manifestations are abrupt onset of painful erythematous plaques or nodules most commonly involving the extremities, often accompanied by pyrexia, elevated neutrophil count, elevation of the erythrocyte sedimentation rate, and positive C-reactive protein. The use of glucocorticoids is the most common treatment for this disease, and most patients see a rapid improvement in skin lesions; however, some may experience infection or recurrence after withdrawal. Some patients with Sweet’s syndrome are accompanied by oral lesions, but cases of oral mucosal damage have been rarely reported, and this condition is easily misdiagnosed. Conclusion Oral mucosal lesions may be extraterritorial manifestations of Sweet’s syndrome, and the patient’s systemic condition should be comprehensively considered. Skin biopsy should be completed as soon as possible to make a clear diagnosis, so as not to delay the disease

Geomagnetic pulsations caused by the Sumatra earthquake on December 26, 2004

A long period Pc5 pulsation was observed at Phimai in Thailand, shortly after the origin time of the Sumatra earthquake on December 26, 2004. The localized nature and the period of oscillations suggest that the long period magnetic pulsation was generated by dynamo action in the lower ionosphere, set up by an atmospheric pressure pulse which propagated vertically as an acoustic wave when the ocean floor suddenly moved vertically. It is speculated that a Pc3 type pulsation observed at Tong Hai in China, 10 degrees north of Phimai in latitude, was the result of magnetic field line resonance with a magnetosonic wave generated from the electric and magnetic fields of the dynamo current caused by the Earthquake.publishersversionPeer reviewe

Recruitment of MLL1 complex is essential for SETBP1 to induce myeloid transformation

Abnormal activation of SETBP1 due to overexpression or missense mutations occurs frequently in various myeloid neoplasms and associates with poor prognosis. Direct activation of Hoxa9/Hoxa10/Myb transcription by SETBP1 and its missense mutants is essential for their transforming capability; however, the underlying epigenetic mechanisms remain elusive. We found that both SETBP1 and its missense mutant SETBP1(D/N) directly interact with histone methyltransferase MLL1. Using a combination of ChIP-seq and RNA-seq analysis in primary hematopoietic stem and progenitor cells, we uncovered extensive overlap in their genomic occupancy and their cooperation in activating many oncogenic transcription factor genes including Hoxa9/Hoxa10/Myb and a large group of ribosomal protein genes. Genetic ablation of Mll1 as well as treatment with an inhibitor of the MLL1 complex OICR-9429 abrogated Setbp1/Setbp1(D/N)- induced transcriptional activation and transformation. Thus, the MLL1 complex plays a critical role in Setbp1-induced transcriptional activation and transformation and represents a promising target for treating myeloid neoplasms with SETBP1 activation

A wafer-scale two-dimensional platinum monosulfide ultrathin film via metal sulfurization for high performance photoelectronics

2D nonlayered materials have attracted enormous research interests due to their novel physical and chemical properties with confined dimensions. Platinum monosulfide as one of the most common platinum-group minerals has been less studied due to either the low purity in the natural product or the extremely high-pressure conditions for synthesis. Recently, platinum monosulfide (PtS) 2D membranes have emerged as rising-star materials for fundamental Raman and X-ray photoelectron spectral analysis as well as device exploration. However, a large-area homogeneous synthesis route has not yet been proposed and released. In this communication, we report a facile metal sulfurization strategy for the synthesis of a 4-inch wafer-scale PtS film. Enhanced characterization tools have been employed for thorough analysis of the crystal structure, chemical environment, vibrational modes, and atomic configuration. Furthermore, through theoretical calculations the phase diagram of the Pt-S compound has been plotted for showing the successful formation of PtS in our synthesis conditions. Eventually, a high-quality PtS film has been reflected in device demonstration by a photodetector. Our approach may shed light on the mass production of PtS films with precise control of their thickness and homogeneity as well as van der Waals heterostructures and related electronic devices.Web of Science331505149

Diastereomers of the pentacoordinate chiral phosphorus compounds in solution: absolute configurations and predominant conformations

The absolute structural information about four sets of diastereomers of pentacoordinate spirophosphoranes, derived separately from L (or D)-phenylglycine and L (or D)-phenylalanine, has been obtained by using vibrational circular dichroism (VCD) spectroscopic measurements and density functional theory (DFT) for the first time. Each compound contains a stereogenic centre at the phosphorus center and two at the amino acid ligands. Geometric searches at the B3LYP/6-311++ G** level have been performed for all possible low energy conformers whose vibrational absorption (VA) and VCD spectra have also been simulated. The good agreement between the experimental VA and VCD spectra in the dimethyl sulfoxide (DMSO) solution and the simulated ones allows us to assign the absolute configurations and predominant conformations of these pentacoordinate phosphorus compounds with high confidence. Solvent effects have been examined by using both the experimental measurements and theoretical calculations. The implicit continuous polarization model and the explicit solute-solvent intermolecular hydrogen-bonding model have been considered to understand the effects of DMSO on the spectra observed. The influence of basis sets and different functionals on the VA and VCD spectra of this type of coordination compounds has also been investigated.University of Alberta ; Natural Sciences and Engineering Research Council of Canada ; Alberta Ingenuity ; NSFC [20732004, 20972130, 20773098]; Petro-Canad